BACKGROUND Superimposed high-frequency jet ventilation(SHFJV)is suitable for respiratory motion reduction and essential for effective lung tumor ablation.Fluid filling of the target lung wing one-lung flooding(OLF)is ...BACKGROUND Superimposed high-frequency jet ventilation(SHFJV)is suitable for respiratory motion reduction and essential for effective lung tumor ablation.Fluid filling of the target lung wing one-lung flooding(OLF)is necessary for therapeutic ultrasound applications.However,whether unilateral SHFJV allows adequate hemodynamics and gas exchange is unclear.AIM To compared SHFJV with pressure-controlled ventilation(PCV)during OLF by assessing hemodynamics and gas exchange in different animal positions.METHODS SHFJV or PCV was used alternatingly to ventilate the non-flooded lungs of the 12 anesthetized pigs during OLF.The animal positions were changed from left lateral position to supine position(SP)to right lateral position(RLP)every 30 min.In each position,ventilation was maintained for 15 min in both modalities.Hemodynamic variables and arterial blood gas levels were repeatedly measured.RESULTS Unilateral SHFJV led to lower carbon dioxide removal than PCV without abnormally elevated carbon dioxide levels.SHFJV slightly decreased oxygenation in SP and RLP compared with PCV;the lowest values of PaO_(2) and PaO_(2)/FiO_(2) ratio were found in SP[13.0;interquartile range(IQR):12.6-5.6 and 32.5(IQR:31.5-38.9)kPa].Conversely,during SHFJV,the shunt fraction was higher in all animal positions(highest in the RLP:0.30).CONCLUSION In porcine model,unilateral SHFJV may provide adequate ventilation in different animal positions during OLF.Lower oxygenation and CO_(2) removal rates compared to PCV did not lead to hypoxia or hypercapnia.SHFJV can be safely used for lung tumor ablation to minimize ventilation-induced lung motion.展开更多
BACKGROUND Sudden sensorineural hearing loss(SSNHL),characterized by a rapid and unexplained loss of hearing,particularly at moderate to high frequencies,presents a significant clinical challenge.The therapeutic use o...BACKGROUND Sudden sensorineural hearing loss(SSNHL),characterized by a rapid and unexplained loss of hearing,particularly at moderate to high frequencies,presents a significant clinical challenge.The therapeutic use of methylprednisolone sodium succinate(MPSS)via different administration routes,in combination with conventional medications,remains a topic of interest.AIM To compare the therapeutic efficacy of MPSS administered via different routes in combination with conventional drugs for the treatment of mid-to high-frequency SSNHL.METHODS The medical records of 109 patients with mid-to high-frequency SSNHL were analyzed.The patients were divided into three groups based on the route of administration:Group A[intratympanic(IT)injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection],Group B(intravenous injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection),and Group C(single IT injection of MPSS).The intervention effects were compared and analyzed.RESULTS The posttreatment auditory thresholds in Group A(21.23±3.34)were significantly lower than those in Groups B(28.52±3.36)and C(30.23±4.21;P<0.05).Group A also exhibited a significantly greater speech recognition rate(92.23±5.34)than Groups B and C.The disappearance time of tinnitus,time to hearing recovery,and disappearance time of vertigo in Group A were significantly shorter than those in Groups B and C(P<0.05).The total effective rate in Group A(97.56%)was significantly greater than that in Groups B and C(77.14%and 78.79%,χ^(2)=7.898,P=0.019).Moreover,the incidence of adverse reactions in Groups A and C was significantly lower than that in Group B(4.88%,3.03%vs 2.57%,χ^(2)=11.443,P=0.003),and the recurrence rate in Group A was significantly lower than that in Groups B and C(2.44%vs 20.00%vs 21.21%,χ^(2)=7.120,P=0.028).CONCLUSION IT injection of MPSS combined with conventional treatment demonstrates superior efficacy and safety compared to systemic administration via intravenous infusion and a single IT injection of MPSS.This approach effectively improves patients'hearing and reduces the risk of disease recurrence.展开更多
Rapid acquisition of the kinematic deformation field and seismic intensity distribution of large earthquakes is crucial for postseismic emergency rescue,disaster assessment,and future seismic risk research.The advance...Rapid acquisition of the kinematic deformation field and seismic intensity distribution of large earthquakes is crucial for postseismic emergency rescue,disaster assessment,and future seismic risk research.The advancement of GNSS observation and data processing makes it play an important role in this field,especially the high-frequency GNSS.We used the differential positioning method to calculate the 1 HZ GNSS data from 98 sites within 1000 km of the M_(S)7.4 Maduo earthquake epicenter.The kinematic deformation field and the distribution of the seismic intensity by using the peak ground velocity derived from displacement waveforms were obtained.The results show that:1)Horizontal coseismic response deformation levels ranging from 25 mm to 301 mm can be observed within a 1000 km radius from the epicenter.Coseismic response deformation on the east and west sides shows bilateral asymmetry,which markedly differs from the symmetry presented by surface rupture.2)The seismic intensity obtained through high-frequency GNSS and field investigations exhibits good consistency of the scope and orientation in the high seismic intensity area,although the former is generally slightly smaller than the latter.3)There may exist obstacles on the eastern side of the seismogenic fault.The Maduo earthquake induced a certain tectonic stress loading effect on the western Kunlun Pass-Jiangcuo fault(KPJF)and Maqin-Maqu segment,resulting in higher seismic risk in the future.展开更多
The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex orientations.The vibration caused by the high-frequency units during regular operation is ...The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex orientations.The vibration caused by the high-frequency units during regular operation is supported by the foundation of the units,and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts,leading to variations in the dynamic response of the foundation.The high-frequency units yield significantly diverse outcomes under different startup conditions and times,resulting in failure to meet operational requirements,influencing the normal function of the tunnel,and causing harm to the foundation structure,personnel,and property in severe cases.This article formulates a finite element numerical computation model for solid elements using three-dimensional elastic body theory and integrates field measurements to substantiate and ascertain the crucial parameter configurations of the finite element model.By proposing a comprehensive startup timing function for high-frequency dynamic machines under different startup conditions,simulating the frequency andmagnitude variations during the startup process,and suggesting functions for changes in frequency and magnitude,a simulated startup schedule function for high-frequency machines is created through coupling.Taking into account the selection of the transient dynamic analysis step length,the dynamic response results for the lower dynamic foundation during its fundamental frequency crossing process are obtained.The validation checks if the structural magnitude surpasses the safety threshold during the critical phase of unit startup traversing the structural resonance region.The design recommendations for high-frequency units’dynamic foundations are provided,taking into account the startup process of the machine and ensuring the safe operation of the tunnel.展开更多
High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is...High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is becoming more and more vital for the development of wind power.The HFO phenomenon of wind turbines under different scenarios usually has different mechanisms.Hence,engineers need to acquire the working mechanisms of the different HFO damping technologies and select the appropriate one to ensure the effective implementation of oscillation damping in practical engineering.This paper introduces the general assumptions of WPGS when analyzing HFO,systematically summarizes the reasons for the occurrence of HFO in different scenarios,deeply analyses the key points and difficulties of HFO damping under different scenarios,and then compares the technical performances of various types of HFO suppression methods to provide adequate references for engineers in the application of technology.Finally,this paper discusses possible future research difficulties in the problem of HFO,as well as the possible future trends in the demand for HFO damping.展开更多
Dielectric barrier discharge(DBD)plasma excited by a high-frequency alternating-current(AC)power supply is widely employed for the degradation of volatile organic compounds(VOCs).However,the thermal effect generated d...Dielectric barrier discharge(DBD)plasma excited by a high-frequency alternating-current(AC)power supply is widely employed for the degradation of volatile organic compounds(VOCs).However,the thermal effect generated during the discharge process leads to energy waste and low energy utilization efficiency.In this work,an innovative DBD thermally-conducted catalysis(DBD-TCC)system,integrating high-frequency AC-DBD plasma and its generated thermal effects to activate the Co/SBA-15 catalyst,was employed for toluene removal.Specifically,Co/SBA-15 catalysts are closely positioned to the ground electrode of the plasma zone and can be heated and activated by the thermal effect when the voltage exceeds 10 k V.At12.4 k V,the temperature in the catalyst zone reached 261℃ in the DBD-TCC system,resulting in an increase in toluene degradation efficiency of 17%,CO_(2)selectivity of 21.2%,and energy efficiency of 27%,respectively,compared to the DBD system alone.In contrast,the DBD thermally-unconducted catalysis(DBD-TUC)system fails to enhance toluene degradation due to insufficient heat absorption and catalytic activation,highlighting the crucial role of AC-DBD generated heat in the activation of the catalyst.Furthermore,the degradation pathway and mechanism of toluene in the DBD-TCC system were hypothesized.This work is expected to provide an energy-efficient approach for high-frequency AC-DBD plasma removal of VOCs.展开更多
The present study aimed to dynamically observe the segmental and global myocardial movements of the left ventricle during coronary artery bypass grafting by transesophageal speckle-tracking echocardiography,and to ass...The present study aimed to dynamically observe the segmental and global myocardial movements of the left ventricle during coronary artery bypass grafting by transesophageal speckle-tracking echocardiography,and to assess the effect of sevoflurane on cardiac function.Sixty-four patients scheduled for the off-pump coronary artery bypass grafting were randomly divided into a sevoflurane-based anesthesia(AS)group and a propofolbased total intravenous anesthesia(AA)group.The AS group demonstrated a higher absolute value of left ventricular global longitudinal strain than that of the AA group at both T1(after harvesting all grafts and before coronary anastomosis)and T_(2)(30 min after completing all coronary anastomoses)(P<0.05).Moreover,strain improvement in the segment with the highest preoperative strain was significantly reduced in the AS group,compared with the AA group at both T1 and T_(2)(P<0.01).The flow of the left internal mammary artery-left anterior descending artery graft was superior,and the postoperative concentration of troponin T decreased rapidly in the AS group,compared with the AA group(P<0.05).Compared with total intravenous anesthesia,sevoflurane resulted in a significantly higher global longitudinal strain,stroke volume,and cardiac output.Sevoflurane also led to an amelioration in the condition of the arterial graft.Furthermore,sevoflurane significantly reduced strain improvement in the segmental myocardium with a high preoperative strain value.The findings need to be replicated in larger studies.展开更多
Objective To explore the value of deep learning(DL)models semi-automatic training system for automatic optimization of clinical image quality control of transthoracic echocardiography(TTE).Methods Totally 1250 TTE vid...Objective To explore the value of deep learning(DL)models semi-automatic training system for automatic optimization of clinical image quality control of transthoracic echocardiography(TTE).Methods Totally 1250 TTE videos from 402 patients were retrospectively collected,including 490 apical four chamber(A4C),310 parasternal long axis view of left ventricle(PLAX)and 450 parasternal short axis view of great vessel(PSAX GV).The videos were divided into development set(245 A4C,155 PLAX,225 PSAX GV),semi-automated training set(98 A4C,62 PLAX,90 PSAX GV)and test set(147 A4C,93 PLAX,135 PSAX GV)at the ratio of 5∶2∶3.Based on development set and semi-automatic training set,DL model of quality control was semi-automatically iteratively optimized,and a semi-automatic training system was constructed,then the efficacy of DL models for recognizing TTE views and assessing imaging quality of TTE were verified in test set.Results After optimization,the overall accuracy,precision,recall,and F1 score of DL models for recognizing TTE views in test set improved from 97.33%,97.26%,97.26%and 97.26%to 99.73%,99.65%,99.77%and 99.71%,respectively,while the overall accuracy for assessing A4C,PLAX and PSAX GV TTE as standard views in test set improved from 89.12%,83.87%and 90.37%to 93.20%,90.32%and 93.33%,respectively.Conclusion The developed DL models semi-automatic training system could improve the efficiency of clinical imaging quality control of TTE and increase iteration speed.展开更多
Congenital heart disease(CHD)is the most common type of birth defect,representing a significant cause of peri-natal morbidity and mortality.Early diagnosis of such anomalies is crucial for improving outcomes.Current p...Congenital heart disease(CHD)is the most common type of birth defect,representing a significant cause of peri-natal morbidity and mortality.Early diagnosis of such anomalies is crucial for improving outcomes.Current pro-tocols recommend a qualitative assessment of cardiac structures using two-dimensional ultrasound(2DUS)and color Doppler imaging.In cases of suspected abnormalities,quantitative assessments through cardiac structure measurements and reference curves can aid in accurate diagnosis.Similar to centiles widely employed in obste-trics,Z-scores provide more precise quantification of various cardiac structures,particularly at the extremes of the curve.While the development of reference curves and Z-scores has progressed over the past two decades,a lack of standardization in measurements and statistical methodology for their determination is evident.Establishing reference curves requires adherence to specific recommendations to improve their accuracy.The purpose of this study is to provide a narrative review of the major studies that have generated reference values for cardiac struc-tures using 2DUS and Z-scores,to evaluate their methodology,and to provide a summary of the results.展开更多
Artificial intelligence(AI)technology has been increasingly used in medical field with its rapid developments.Echocardiography is one of the best imaging methods for clinical diagnosis of heart diseases,and combining ...Artificial intelligence(AI)technology has been increasingly used in medical field with its rapid developments.Echocardiography is one of the best imaging methods for clinical diagnosis of heart diseases,and combining with AI could further improve its diagnostic efficiency.Though the applications of AI in echocardiography remained at a relatively early stage,a variety of automated quantitative and analytical techniques were rapidly emerging and initially entered clinical practice.The status of clinical applications of AI in echocardiography were reviewed in this article.展开更多
Background Atrial septal defect(ASD)is one of the most common congenital heart diseases.The diagnosis of ASD via transthoracic echocardiography is subjective and time-consuming.Methods The objective of this study was ...Background Atrial septal defect(ASD)is one of the most common congenital heart diseases.The diagnosis of ASD via transthoracic echocardiography is subjective and time-consuming.Methods The objective of this study was to evaluate the feasibility and accuracy of automatic detection of ASD in children based on color Doppler echocardiographic static images using end-to-end convolutional neural networks.The proposed depthwise separable convolution model identifies ASDs with static color Doppler images in a standard view.Among the standard views,we selected two echocardiographic views,i.e.,the subcostal sagittal view of the atrium septum and the low parasternal four-chamber view.The developed ASD detection system was validated using a training set consisting of 396 echocardiographic images corresponding to 198 cases.Additionally,an independent test dataset of 112 images corresponding to 56 cases was used,including 101 cases with ASDs and 153 cases with normal hearts.Results The average area under the receiver operating characteristic curve,recall,precision,specificity,F1-score,and accuracy of the proposed ASD detection model were 91.99,80.00,82.22,87.50,79.57,and 83.04,respectively.Conclusions The proposed model can accurately and automatically identify ASD,providing a strong foundation for the intelligent diagnosis of congenital heart diseases.展开更多
A high-frequency magnetic probe is designed and developed on the XuanL ong-50(EXL-50)spherical torus to measure high-frequency magnetic field fluctuation.The magnetic loop,radio filters,radio-frequency limiter,and dat...A high-frequency magnetic probe is designed and developed on the XuanL ong-50(EXL-50)spherical torus to measure high-frequency magnetic field fluctuation.The magnetic loop,radio filters,radio-frequency limiter,and data acquisition system of the probe are comprehensively examined.The fluctuation data from the EXL-50 plasma are analyzed in the time–frequency domain using fast Fourier transforms.Moreover,distinct high-frequency instabilities are detected using this diagnostic system.In particular,significant frequency chirping is observed,which is consistent with the bumpon-tail drive instability predicted using the Berk–Breizman model.展开更多
Magneto-dielectric properties of Co_(2)Z ferrite materials are tuned via Gd doping for applications in high-frequency antennas and filters in the present work.Ba_(3)Co_(2)Fe_(24-x)Gd_(x)O_(41)(x=0.00,0.05,0.10,0.15,an...Magneto-dielectric properties of Co_(2)Z ferrite materials are tuned via Gd doping for applications in high-frequency antennas and filters in the present work.Ba_(3)Co_(2)Fe_(24-x)Gd_(x)O_(41)(x=0.00,0.05,0.10,0.15,and 0.20)materials are successfully prepared by using solid-state method at 925℃for 4 h with 2.5-wt%Bi_(2)O_(3)sintering aids.The content of Gd^(3+)ion can affect micromorphology,grain size,bulk density,and magneto-dielectric properties of the ferrite.With Gd^(3+)ion content increasing,saturation magnetization(Ms)first increases and then decreases.The maximum value of Ms is 44.86 emu/g at x=0.15.Additionally,sites occupied by Gd^(3+)ions can change magnetic anisotropy constant of the ferrite.Magnetocrystalline anisotropy constant(K_1)is derived from initial magnetization curve,and found to be related to spin-orbit coupling and intersublattice interactions between metal ions.The real part of magnetic permeability(μ′)and real part of dielectric permittivity(ε′)are measured in a frequency range of 10 MHz-1 GHz.When x=0.15,material has excellent magneto-dielectric properties(μ′≈12.2 andε′≈17.61),low magnetic loss(tanδμ≈0.03 at 500 MHz),and dielectric loss(tanδε≈0.04 at 500 MHz).The results show that Gd-doped Co_(2)Z ferrite has broad application prospects in multilayer filters and high-frequency antennas.展开更多
A new type of Ni/MgO catalyst was prepared using atmospheric high-frequency discharge cold plasma. The influences of conventional method, plasma method, and plasma plus calcination method on the catalytic activity wer...A new type of Ni/MgO catalyst was prepared using atmospheric high-frequency discharge cold plasma. The influences of conventional method, plasma method, and plasma plus calcination method on the catalytic activity were studied and the CO2 reforming of methane was chosen as the probe reaction. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy, and CO2 temperature-programmed surface reaction techniques. The results suggested that the nickel-based catalyst prepared by plasma plus calcination method possessed a smaller particle size and a higher dispersion of active component, better low-temperature activity and enhanced anti-coking ability. The conversion of CO2 and CH4 was 90.70% and 89.37%, respectively, and the reaction lasted for 36 h without obvious deactivation under 101.325 kPa and 750°C with CO2/CH4 = 1/1.展开更多
BACKGROUND: Deep-brain stimulation has proven to be beneficial in the treatment of Parkinson's disease (PD) patients. OBJECTIVE: To investigate the effects of high-frequency stimulation (HFS) to the subthalamic...BACKGROUND: Deep-brain stimulation has proven to be beneficial in the treatment of Parkinson's disease (PD) patients. OBJECTIVE: To investigate the effects of high-frequency stimulation (HFS) to the subthalamic nucleus (STN) on neuronal apoptosis and apoptosis-related gene expression in the substantia nigra pars compacta, and to analyze the neuroprotective effect of HFS-STN. DESIGN, TIME AND SETTING: Neuronal morphology experiments were performed in the Beijing Neurosurgical Institute from May to December in 2005. MATERIALS: Forty healthy, adult, Sprague Dawley rats were used to establish a PD model with a unilateral microinjection of 6-hydroxydopamine into two target areas of the right medial forebrain bundle. 6-hydroxydopamine was purchased from Sigma (USA); high-frequency electrical stimulator was produced by World Precision Instruments (USA); Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) kit was a product of Nanjing Jiancheng Technology Co., Ltd. (China); and Bcl-2 and Bax protein assay kit were purchased from Wuhan Boster Bioengineering Co., Ltd. (China). METHODS: Forty rats were randomly divided into three groups. The stimulation group (n = 15) received HFS-STN on the day of PD modeling. The PD model group (n = 15) was used to establish the PD model. The control group (n = 10) was injected with normal saline containing 0.2 g/L ascorbic acid into two areas of the right medial forebrain bundle. MAIN OUTCOME MEASURES: Survival of dopaminergic neurons in the substantia nigra pars compacta was determined using Nissl staining. Apoptosis of dopaminergic neurons was detected using TUNEL techniques. Expression of anti-apoptotic protein, Bcl-2, and pro-apoptotic protein, Bax, were assayed by immunohistochemistry. RESULTS: Following 6-hydroxydopamine injection, the number of substantia nigra pars compacta neurons was reduced in the stimulation and PD model groups, compared to the control group. At 2 and 4 weeks post-surgery, the grey value of Nissl stained images was significantly less in the PD model and stimulation groups (P 〈 0.05), and the stimulation group exhibited greater grey values compared to the model group (P 〈 0.05). At 2 and 4 weeks post-surgery, the number of apoptotic neurons was significantly less in the stimulation group compared to the model group (P 〈 0.05). In addition, Bcl-2 and Bax expression, as well as the Bcl-2/Bax ratio, was much higher in the stimulation group compared to the model group (P 〈 0.05). CONCLUSION: HFS-STN has a neuroprotective effect on dopaminergic neurons in the substantia nigra pars compacta of PD rats by promoting Bcl-2 expression, inhibiting Bax expression, and reducing the number of apoptotic dopaminergic neurons.展开更多
Most of model cotton varieties used in tissue culture have glands on both the reproductive and vegetative parts of the plant.These glands contain compounds that are toxic to human and non-ruminant animals.The presence...Most of model cotton varieties used in tissue culture have glands on both the reproductive and vegetative parts of the plant.These glands contain compounds that are toxic to human and non-ruminant animals.The presence of these compounds limits their usage as food and feed.To obtain a glandless cotton variety with high-frequency somatic embryo production ability,27 glandless varieties展开更多
The effects of cardiomyocyte grafting on left ventricular (LV) remodeling and function in rats with chronic myocardial infarction were evaluated using high-frequency ultrasound. Chronic myocardial infarction was ind...The effects of cardiomyocyte grafting on left ventricular (LV) remodeling and function in rats with chronic myocardial infarction were evaluated using high-frequency ultrasound. Chronic myocardial infarction was induced in 50 Wister rats by ligating the left anterior descending artery. They were randomized into two groups: a trial group that received neonatal rat cardiomyocyte trans- plantation (n=25) and a control group which were given intramyocardial injection of culture medium (n=25). The left ventricular (LV) geometry and function were evaluated by high-frequency ultrasound before and 4 weeks after the cell transplantation. After the final evaluation, all rats were sacrificed for histological study. The results showed that 4 weeks after the cell transplantation, as compared with the control group, the LV end-systolic dimension, end-diastolic dimension, end-systolic volume and end-diastolic volume were significantly decreased and the LV anterior wall end-diastolic thickness, LV ejection fraction and fractional shortening were significantly increased in the trial group (P〈0.01). Histological study showed that transplanted neonatal rat cardiomyocytes were found in all host hearts and identified by Brdu staining. It was suggested that transplantation of neonatal rat cardiomyocytes can reverse cardiac remodeling and improve heart function in chronic myocardial infarction rats. High-frequency ultrasound can be used as a reliable technique for the non-invasive evaluation of the effect of cardiomyocyte transplantation.展开更多
AIM: To compare the corneal endothelial cell counts pre-and post-operation, ultrastructure of anterior lens capsule and surgical completion after diathermic highfrequency capsulorhexis(DHC) and continuous curviline...AIM: To compare the corneal endothelial cell counts pre-and post-operation, ultrastructure of anterior lens capsule and surgical completion after diathermic highfrequency capsulorhexis(DHC) and continuous curvilinear capsulorrhexis(CCC) applied in phacoemulsification(PHACO) of white cataract surgery.METHODS: Sixty-six eyes of 66 patients(33 males and 33 females) with cataract aged between 60 and 80 y(mean 72.5±5.5) were recruited and undergone the surgery from June 2014 to November 2016. Anterior lens capsule, derived from two kinds of capsulorhexis, were randomly divided into two groups according to random number table. The ultrastructure of the capsule edge and its closer tissue were observed by transmission electron microscopy(TEM) and optical microscopy respectively. The surgical completion conditions and corneal endothelial cell counts were analyzed pre-and post-operation after two capsulorhexis.RESULTS: The capsule derived from CCC had smooth edge, well-organized cellular structure and the cells filling into the cutting edge under TEM and optical microscopy. The capsule derived from DHC had an approximate 60 banded area of cell degeneration and necrosis, with dentiform prominences at the edge of the capsule, and no cell structure was observed at this area. The corneal endothelial cell counts of both groups were slightly declined 1 wk post-operation compared with that of preoperation. There was no statistical difference between the two groups(t=1.63, P〉0.05).CONCLUSION: DHC shows good clinical value in white mature and hypermature cataract surgery.展开更多
It is difficult to conduct shaking table tests that require large-displacement high-frequency seismic excitation due to the limited capacity of existing electrohydraulic servo systems.To address this problem,a double-...It is difficult to conduct shaking table tests that require large-displacement high-frequency seismic excitation due to the limited capacity of existing electrohydraulic servo systems.To address this problem,a double-layer shaking table(DLST)is proposed.The DLST has two layers of one table each(i.e.,an upper table and lower table)and aims at reproducing target seismic excitation on the upper table.The original signal is separated into two signals(i.e.,a high-frequency signal and low-frequency signal)through a fast Fourier transform/inverse fast Fourier transform process,and these signals are applied to the two tables separately.The actuators connected to different tables only need to generate large-displacement low-frequency or small-displacement high-frequency movements.The three-variable control method is used to generate large-displacement but low-frequency motion of the lower table and high-frequency but small-displacement motion of the upper table relative to the table beneath.A series of simulations are carried out using MATLAB/Simulink.The simulation results suggest that the DLST can successfully generate large-displacement high-frequency excitation.The control strategy in which the lower table tracks the low-frequency signal and the upper table tracks the original signal is recommended.展开更多
High-frequency magnetic properties, such as core loss, coercivity and amplitude permeabilityof a newly-developed nanocrystalline Fe72.5Cu1Nb2V2Si13.5B9 alloy in the wide ranges of f =20-103 kHz, Bm = 0.01~0.6 T and Bm...High-frequency magnetic properties, such as core loss, coercivity and amplitude permeabilityof a newly-developed nanocrystalline Fe72.5Cu1Nb2V2Si13.5B9 alloy in the wide ranges of f =20-103 kHz, Bm = 0.01~0.6 T and Bmf = 10~40 (T.kHz) have been measured. A largeamount of experimental data have been fitted by a computer, thus obtaining several expressionsrepresenting the influence of frequency on high-frequency magnetic properties, that are useful inpractical applications.展开更多
文摘BACKGROUND Superimposed high-frequency jet ventilation(SHFJV)is suitable for respiratory motion reduction and essential for effective lung tumor ablation.Fluid filling of the target lung wing one-lung flooding(OLF)is necessary for therapeutic ultrasound applications.However,whether unilateral SHFJV allows adequate hemodynamics and gas exchange is unclear.AIM To compared SHFJV with pressure-controlled ventilation(PCV)during OLF by assessing hemodynamics and gas exchange in different animal positions.METHODS SHFJV or PCV was used alternatingly to ventilate the non-flooded lungs of the 12 anesthetized pigs during OLF.The animal positions were changed from left lateral position to supine position(SP)to right lateral position(RLP)every 30 min.In each position,ventilation was maintained for 15 min in both modalities.Hemodynamic variables and arterial blood gas levels were repeatedly measured.RESULTS Unilateral SHFJV led to lower carbon dioxide removal than PCV without abnormally elevated carbon dioxide levels.SHFJV slightly decreased oxygenation in SP and RLP compared with PCV;the lowest values of PaO_(2) and PaO_(2)/FiO_(2) ratio were found in SP[13.0;interquartile range(IQR):12.6-5.6 and 32.5(IQR:31.5-38.9)kPa].Conversely,during SHFJV,the shunt fraction was higher in all animal positions(highest in the RLP:0.30).CONCLUSION In porcine model,unilateral SHFJV may provide adequate ventilation in different animal positions during OLF.Lower oxygenation and CO_(2) removal rates compared to PCV did not lead to hypoxia or hypercapnia.SHFJV can be safely used for lung tumor ablation to minimize ventilation-induced lung motion.
文摘BACKGROUND Sudden sensorineural hearing loss(SSNHL),characterized by a rapid and unexplained loss of hearing,particularly at moderate to high frequencies,presents a significant clinical challenge.The therapeutic use of methylprednisolone sodium succinate(MPSS)via different administration routes,in combination with conventional medications,remains a topic of interest.AIM To compare the therapeutic efficacy of MPSS administered via different routes in combination with conventional drugs for the treatment of mid-to high-frequency SSNHL.METHODS The medical records of 109 patients with mid-to high-frequency SSNHL were analyzed.The patients were divided into three groups based on the route of administration:Group A[intratympanic(IT)injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection],Group B(intravenous injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection),and Group C(single IT injection of MPSS).The intervention effects were compared and analyzed.RESULTS The posttreatment auditory thresholds in Group A(21.23±3.34)were significantly lower than those in Groups B(28.52±3.36)and C(30.23±4.21;P<0.05).Group A also exhibited a significantly greater speech recognition rate(92.23±5.34)than Groups B and C.The disappearance time of tinnitus,time to hearing recovery,and disappearance time of vertigo in Group A were significantly shorter than those in Groups B and C(P<0.05).The total effective rate in Group A(97.56%)was significantly greater than that in Groups B and C(77.14%and 78.79%,χ^(2)=7.898,P=0.019).Moreover,the incidence of adverse reactions in Groups A and C was significantly lower than that in Group B(4.88%,3.03%vs 2.57%,χ^(2)=11.443,P=0.003),and the recurrence rate in Group A was significantly lower than that in Groups B and C(2.44%vs 20.00%vs 21.21%,χ^(2)=7.120,P=0.028).CONCLUSION IT injection of MPSS combined with conventional treatment demonstrates superior efficacy and safety compared to systemic administration via intravenous infusion and a single IT injection of MPSS.This approach effectively improves patients'hearing and reduces the risk of disease recurrence.
基金supported by Grants from the National Natural Science Foundation of China(42004010)the Beijing Natural Science Foundation(8204077)。
文摘Rapid acquisition of the kinematic deformation field and seismic intensity distribution of large earthquakes is crucial for postseismic emergency rescue,disaster assessment,and future seismic risk research.The advancement of GNSS observation and data processing makes it play an important role in this field,especially the high-frequency GNSS.We used the differential positioning method to calculate the 1 HZ GNSS data from 98 sites within 1000 km of the M_(S)7.4 Maduo earthquake epicenter.The kinematic deformation field and the distribution of the seismic intensity by using the peak ground velocity derived from displacement waveforms were obtained.The results show that:1)Horizontal coseismic response deformation levels ranging from 25 mm to 301 mm can be observed within a 1000 km radius from the epicenter.Coseismic response deformation on the east and west sides shows bilateral asymmetry,which markedly differs from the symmetry presented by surface rupture.2)The seismic intensity obtained through high-frequency GNSS and field investigations exhibits good consistency of the scope and orientation in the high seismic intensity area,although the former is generally slightly smaller than the latter.3)There may exist obstacles on the eastern side of the seismogenic fault.The Maduo earthquake induced a certain tectonic stress loading effect on the western Kunlun Pass-Jiangcuo fault(KPJF)and Maqin-Maqu segment,resulting in higher seismic risk in the future.
基金Smart Integration Key Technologies and Application Demonstrations of Large Scale Underground Space Disaster Prevention and Reduction in Guangzhou International Financial City([2021]–KJ058).
文摘The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex orientations.The vibration caused by the high-frequency units during regular operation is supported by the foundation of the units,and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts,leading to variations in the dynamic response of the foundation.The high-frequency units yield significantly diverse outcomes under different startup conditions and times,resulting in failure to meet operational requirements,influencing the normal function of the tunnel,and causing harm to the foundation structure,personnel,and property in severe cases.This article formulates a finite element numerical computation model for solid elements using three-dimensional elastic body theory and integrates field measurements to substantiate and ascertain the crucial parameter configurations of the finite element model.By proposing a comprehensive startup timing function for high-frequency dynamic machines under different startup conditions,simulating the frequency andmagnitude variations during the startup process,and suggesting functions for changes in frequency and magnitude,a simulated startup schedule function for high-frequency machines is created through coupling.Taking into account the selection of the transient dynamic analysis step length,the dynamic response results for the lower dynamic foundation during its fundamental frequency crossing process are obtained.The validation checks if the structural magnitude surpasses the safety threshold during the critical phase of unit startup traversing the structural resonance region.The design recommendations for high-frequency units’dynamic foundations are provided,taking into account the startup process of the machine and ensuring the safe operation of the tunnel.
基金supported in part by the Fundamental Research Funds for the Central Universities under Grant 2682023CX019National Natural Science Foundation of China under Grant U23B6007 and Grant 52307141Sichuan Science and Technology Program under Grant 2024NSFSC0115。
文摘High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is becoming more and more vital for the development of wind power.The HFO phenomenon of wind turbines under different scenarios usually has different mechanisms.Hence,engineers need to acquire the working mechanisms of the different HFO damping technologies and select the appropriate one to ensure the effective implementation of oscillation damping in practical engineering.This paper introduces the general assumptions of WPGS when analyzing HFO,systematically summarizes the reasons for the occurrence of HFO in different scenarios,deeply analyses the key points and difficulties of HFO damping under different scenarios,and then compares the technical performances of various types of HFO suppression methods to provide adequate references for engineers in the application of technology.Finally,this paper discusses possible future research difficulties in the problem of HFO,as well as the possible future trends in the demand for HFO damping.
基金supported by National Natural Science Foundation of China(No.52177130)the Key Projects for Industrial Prospects and Core Technology Research in Suzhou City(No.SYC2022029)。
文摘Dielectric barrier discharge(DBD)plasma excited by a high-frequency alternating-current(AC)power supply is widely employed for the degradation of volatile organic compounds(VOCs).However,the thermal effect generated during the discharge process leads to energy waste and low energy utilization efficiency.In this work,an innovative DBD thermally-conducted catalysis(DBD-TCC)system,integrating high-frequency AC-DBD plasma and its generated thermal effects to activate the Co/SBA-15 catalyst,was employed for toluene removal.Specifically,Co/SBA-15 catalysts are closely positioned to the ground electrode of the plasma zone and can be heated and activated by the thermal effect when the voltage exceeds 10 k V.At12.4 k V,the temperature in the catalyst zone reached 261℃ in the DBD-TCC system,resulting in an increase in toluene degradation efficiency of 17%,CO_(2)selectivity of 21.2%,and energy efficiency of 27%,respectively,compared to the DBD system alone.In contrast,the DBD thermally-unconducted catalysis(DBD-TUC)system fails to enhance toluene degradation due to insufficient heat absorption and catalytic activation,highlighting the crucial role of AC-DBD generated heat in the activation of the catalyst.Furthermore,the degradation pathway and mechanism of toluene in the DBD-TCC system were hypothesized.This work is expected to provide an energy-efficient approach for high-frequency AC-DBD plasma removal of VOCs.
基金supported by Jiangsu Province Hospital(the First Affiliated Hospital of Nanjing Medical University)Clinical Capacity Enhancement and was awarded to the first author,Chanjuan Gong(Grant No.JSPH-MC-2022-4).
文摘The present study aimed to dynamically observe the segmental and global myocardial movements of the left ventricle during coronary artery bypass grafting by transesophageal speckle-tracking echocardiography,and to assess the effect of sevoflurane on cardiac function.Sixty-four patients scheduled for the off-pump coronary artery bypass grafting were randomly divided into a sevoflurane-based anesthesia(AS)group and a propofolbased total intravenous anesthesia(AA)group.The AS group demonstrated a higher absolute value of left ventricular global longitudinal strain than that of the AA group at both T1(after harvesting all grafts and before coronary anastomosis)and T_(2)(30 min after completing all coronary anastomoses)(P<0.05).Moreover,strain improvement in the segment with the highest preoperative strain was significantly reduced in the AS group,compared with the AA group at both T1 and T_(2)(P<0.01).The flow of the left internal mammary artery-left anterior descending artery graft was superior,and the postoperative concentration of troponin T decreased rapidly in the AS group,compared with the AA group(P<0.05).Compared with total intravenous anesthesia,sevoflurane resulted in a significantly higher global longitudinal strain,stroke volume,and cardiac output.Sevoflurane also led to an amelioration in the condition of the arterial graft.Furthermore,sevoflurane significantly reduced strain improvement in the segmental myocardium with a high preoperative strain value.The findings need to be replicated in larger studies.
文摘Objective To explore the value of deep learning(DL)models semi-automatic training system for automatic optimization of clinical image quality control of transthoracic echocardiography(TTE).Methods Totally 1250 TTE videos from 402 patients were retrospectively collected,including 490 apical four chamber(A4C),310 parasternal long axis view of left ventricle(PLAX)and 450 parasternal short axis view of great vessel(PSAX GV).The videos were divided into development set(245 A4C,155 PLAX,225 PSAX GV),semi-automated training set(98 A4C,62 PLAX,90 PSAX GV)and test set(147 A4C,93 PLAX,135 PSAX GV)at the ratio of 5∶2∶3.Based on development set and semi-automatic training set,DL model of quality control was semi-automatically iteratively optimized,and a semi-automatic training system was constructed,then the efficacy of DL models for recognizing TTE views and assessing imaging quality of TTE were verified in test set.Results After optimization,the overall accuracy,precision,recall,and F1 score of DL models for recognizing TTE views in test set improved from 97.33%,97.26%,97.26%and 97.26%to 99.73%,99.65%,99.77%and 99.71%,respectively,while the overall accuracy for assessing A4C,PLAX and PSAX GV TTE as standard views in test set improved from 89.12%,83.87%and 90.37%to 93.20%,90.32%and 93.33%,respectively.Conclusion The developed DL models semi-automatic training system could improve the efficiency of clinical imaging quality control of TTE and increase iteration speed.
文摘Congenital heart disease(CHD)is the most common type of birth defect,representing a significant cause of peri-natal morbidity and mortality.Early diagnosis of such anomalies is crucial for improving outcomes.Current pro-tocols recommend a qualitative assessment of cardiac structures using two-dimensional ultrasound(2DUS)and color Doppler imaging.In cases of suspected abnormalities,quantitative assessments through cardiac structure measurements and reference curves can aid in accurate diagnosis.Similar to centiles widely employed in obste-trics,Z-scores provide more precise quantification of various cardiac structures,particularly at the extremes of the curve.While the development of reference curves and Z-scores has progressed over the past two decades,a lack of standardization in measurements and statistical methodology for their determination is evident.Establishing reference curves requires adherence to specific recommendations to improve their accuracy.The purpose of this study is to provide a narrative review of the major studies that have generated reference values for cardiac struc-tures using 2DUS and Z-scores,to evaluate their methodology,and to provide a summary of the results.
文摘Artificial intelligence(AI)technology has been increasingly used in medical field with its rapid developments.Echocardiography is one of the best imaging methods for clinical diagnosis of heart diseases,and combining with AI could further improve its diagnostic efficiency.Though the applications of AI in echocardiography remained at a relatively early stage,a variety of automated quantitative and analytical techniques were rapidly emerging and initially entered clinical practice.The status of clinical applications of AI in echocardiography were reviewed in this article.
基金the National Natural Science Foundation of China(61975056)the Shanghai Natural Science Foundation(19ZR1416000)+1 种基金the Science and Technology Commission of Shanghai Municipality(20440713100)the Scientific Development funds for Local Region from the Chinese Government in 2023(XZ202301YD0032C).
文摘Background Atrial septal defect(ASD)is one of the most common congenital heart diseases.The diagnosis of ASD via transthoracic echocardiography is subjective and time-consuming.Methods The objective of this study was to evaluate the feasibility and accuracy of automatic detection of ASD in children based on color Doppler echocardiographic static images using end-to-end convolutional neural networks.The proposed depthwise separable convolution model identifies ASDs with static color Doppler images in a standard view.Among the standard views,we selected two echocardiographic views,i.e.,the subcostal sagittal view of the atrium septum and the low parasternal four-chamber view.The developed ASD detection system was validated using a training set consisting of 396 echocardiographic images corresponding to 198 cases.Additionally,an independent test dataset of 112 images corresponding to 56 cases was used,including 101 cases with ASDs and 153 cases with normal hearts.Results The average area under the receiver operating characteristic curve,recall,precision,specificity,F1-score,and accuracy of the proposed ASD detection model were 91.99,80.00,82.22,87.50,79.57,and 83.04,respectively.Conclusions The proposed model can accurately and automatically identify ASD,providing a strong foundation for the intelligent diagnosis of congenital heart diseases.
基金supported by National Natural Science Foundation of China(No.11706151)。
文摘A high-frequency magnetic probe is designed and developed on the XuanL ong-50(EXL-50)spherical torus to measure high-frequency magnetic field fluctuation.The magnetic loop,radio filters,radio-frequency limiter,and data acquisition system of the probe are comprehensively examined.The fluctuation data from the EXL-50 plasma are analyzed in the time–frequency domain using fast Fourier transforms.Moreover,distinct high-frequency instabilities are detected using this diagnostic system.In particular,significant frequency chirping is observed,which is consistent with the bumpon-tail drive instability predicted using the Berk–Breizman model.
基金the National Key Research and Development Program of China(Grant No.2022YFB3504800)the National Natural Science Foundation of China(Grant Nos.61901142,52003256,and 51902037)the Natural Science Foundation of Shanxi Province,China(Grant No.201901D211259)。
文摘Magneto-dielectric properties of Co_(2)Z ferrite materials are tuned via Gd doping for applications in high-frequency antennas and filters in the present work.Ba_(3)Co_(2)Fe_(24-x)Gd_(x)O_(41)(x=0.00,0.05,0.10,0.15,and 0.20)materials are successfully prepared by using solid-state method at 925℃for 4 h with 2.5-wt%Bi_(2)O_(3)sintering aids.The content of Gd^(3+)ion can affect micromorphology,grain size,bulk density,and magneto-dielectric properties of the ferrite.With Gd^(3+)ion content increasing,saturation magnetization(Ms)first increases and then decreases.The maximum value of Ms is 44.86 emu/g at x=0.15.Additionally,sites occupied by Gd^(3+)ions can change magnetic anisotropy constant of the ferrite.Magnetocrystalline anisotropy constant(K_1)is derived from initial magnetization curve,and found to be related to spin-orbit coupling and intersublattice interactions between metal ions.The real part of magnetic permeability(μ′)and real part of dielectric permittivity(ε′)are measured in a frequency range of 10 MHz-1 GHz.When x=0.15,material has excellent magneto-dielectric properties(μ′≈12.2 andε′≈17.61),low magnetic loss(tanδμ≈0.03 at 500 MHz),and dielectric loss(tanδε≈0.04 at 500 MHz).The results show that Gd-doped Co_(2)Z ferrite has broad application prospects in multilayer filters and high-frequency antennas.
基金supported by the National Natural Science Foundation of China(No.11075113)the Doctoral R&D Foundation of Yibin University(2010B12)
文摘A new type of Ni/MgO catalyst was prepared using atmospheric high-frequency discharge cold plasma. The influences of conventional method, plasma method, and plasma plus calcination method on the catalytic activity were studied and the CO2 reforming of methane was chosen as the probe reaction. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy, and CO2 temperature-programmed surface reaction techniques. The results suggested that the nickel-based catalyst prepared by plasma plus calcination method possessed a smaller particle size and a higher dispersion of active component, better low-temperature activity and enhanced anti-coking ability. The conversion of CO2 and CH4 was 90.70% and 89.37%, respectively, and the reaction lasted for 36 h without obvious deactivation under 101.325 kPa and 750°C with CO2/CH4 = 1/1.
基金Postdoctoral Science Foundation of China, No. 20070420399
文摘BACKGROUND: Deep-brain stimulation has proven to be beneficial in the treatment of Parkinson's disease (PD) patients. OBJECTIVE: To investigate the effects of high-frequency stimulation (HFS) to the subthalamic nucleus (STN) on neuronal apoptosis and apoptosis-related gene expression in the substantia nigra pars compacta, and to analyze the neuroprotective effect of HFS-STN. DESIGN, TIME AND SETTING: Neuronal morphology experiments were performed in the Beijing Neurosurgical Institute from May to December in 2005. MATERIALS: Forty healthy, adult, Sprague Dawley rats were used to establish a PD model with a unilateral microinjection of 6-hydroxydopamine into two target areas of the right medial forebrain bundle. 6-hydroxydopamine was purchased from Sigma (USA); high-frequency electrical stimulator was produced by World Precision Instruments (USA); Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) kit was a product of Nanjing Jiancheng Technology Co., Ltd. (China); and Bcl-2 and Bax protein assay kit were purchased from Wuhan Boster Bioengineering Co., Ltd. (China). METHODS: Forty rats were randomly divided into three groups. The stimulation group (n = 15) received HFS-STN on the day of PD modeling. The PD model group (n = 15) was used to establish the PD model. The control group (n = 10) was injected with normal saline containing 0.2 g/L ascorbic acid into two areas of the right medial forebrain bundle. MAIN OUTCOME MEASURES: Survival of dopaminergic neurons in the substantia nigra pars compacta was determined using Nissl staining. Apoptosis of dopaminergic neurons was detected using TUNEL techniques. Expression of anti-apoptotic protein, Bcl-2, and pro-apoptotic protein, Bax, were assayed by immunohistochemistry. RESULTS: Following 6-hydroxydopamine injection, the number of substantia nigra pars compacta neurons was reduced in the stimulation and PD model groups, compared to the control group. At 2 and 4 weeks post-surgery, the grey value of Nissl stained images was significantly less in the PD model and stimulation groups (P 〈 0.05), and the stimulation group exhibited greater grey values compared to the model group (P 〈 0.05). At 2 and 4 weeks post-surgery, the number of apoptotic neurons was significantly less in the stimulation group compared to the model group (P 〈 0.05). In addition, Bcl-2 and Bax expression, as well as the Bcl-2/Bax ratio, was much higher in the stimulation group compared to the model group (P 〈 0.05). CONCLUSION: HFS-STN has a neuroprotective effect on dopaminergic neurons in the substantia nigra pars compacta of PD rats by promoting Bcl-2 expression, inhibiting Bax expression, and reducing the number of apoptotic dopaminergic neurons.
文摘Most of model cotton varieties used in tissue culture have glands on both the reproductive and vegetative parts of the plant.These glands contain compounds that are toxic to human and non-ruminant animals.The presence of these compounds limits their usage as food and feed.To obtain a glandless cotton variety with high-frequency somatic embryo production ability,27 glandless varieties
文摘The effects of cardiomyocyte grafting on left ventricular (LV) remodeling and function in rats with chronic myocardial infarction were evaluated using high-frequency ultrasound. Chronic myocardial infarction was induced in 50 Wister rats by ligating the left anterior descending artery. They were randomized into two groups: a trial group that received neonatal rat cardiomyocyte trans- plantation (n=25) and a control group which were given intramyocardial injection of culture medium (n=25). The left ventricular (LV) geometry and function were evaluated by high-frequency ultrasound before and 4 weeks after the cell transplantation. After the final evaluation, all rats were sacrificed for histological study. The results showed that 4 weeks after the cell transplantation, as compared with the control group, the LV end-systolic dimension, end-diastolic dimension, end-systolic volume and end-diastolic volume were significantly decreased and the LV anterior wall end-diastolic thickness, LV ejection fraction and fractional shortening were significantly increased in the trial group (P〈0.01). Histological study showed that transplanted neonatal rat cardiomyocytes were found in all host hearts and identified by Brdu staining. It was suggested that transplantation of neonatal rat cardiomyocytes can reverse cardiac remodeling and improve heart function in chronic myocardial infarction rats. High-frequency ultrasound can be used as a reliable technique for the non-invasive evaluation of the effect of cardiomyocyte transplantation.
基金Supported by the Shaanxi Provincial Department of Science and Technology Agency Project (No.2017SF-288)
文摘AIM: To compare the corneal endothelial cell counts pre-and post-operation, ultrastructure of anterior lens capsule and surgical completion after diathermic highfrequency capsulorhexis(DHC) and continuous curvilinear capsulorrhexis(CCC) applied in phacoemulsification(PHACO) of white cataract surgery.METHODS: Sixty-six eyes of 66 patients(33 males and 33 females) with cataract aged between 60 and 80 y(mean 72.5±5.5) were recruited and undergone the surgery from June 2014 to November 2016. Anterior lens capsule, derived from two kinds of capsulorhexis, were randomly divided into two groups according to random number table. The ultrastructure of the capsule edge and its closer tissue were observed by transmission electron microscopy(TEM) and optical microscopy respectively. The surgical completion conditions and corneal endothelial cell counts were analyzed pre-and post-operation after two capsulorhexis.RESULTS: The capsule derived from CCC had smooth edge, well-organized cellular structure and the cells filling into the cutting edge under TEM and optical microscopy. The capsule derived from DHC had an approximate 60 banded area of cell degeneration and necrosis, with dentiform prominences at the edge of the capsule, and no cell structure was observed at this area. The corneal endothelial cell counts of both groups were slightly declined 1 wk post-operation compared with that of preoperation. There was no statistical difference between the two groups(t=1.63, P〉0.05).CONCLUSION: DHC shows good clinical value in white mature and hypermature cataract surgery.
基金Scientific Research Fund of the Institute of Engineering Mechanics,China Earthquake Administration under Grant No.2019EEEVL0502Natural Science Foundation of China under Grant No.52078275+1 种基金the Institute for Guo Qiang,Tsinghua University under Grant No.2019GQC0001Beijing Natural Science Foundation under Grant No.JQ18029。
文摘It is difficult to conduct shaking table tests that require large-displacement high-frequency seismic excitation due to the limited capacity of existing electrohydraulic servo systems.To address this problem,a double-layer shaking table(DLST)is proposed.The DLST has two layers of one table each(i.e.,an upper table and lower table)and aims at reproducing target seismic excitation on the upper table.The original signal is separated into two signals(i.e.,a high-frequency signal and low-frequency signal)through a fast Fourier transform/inverse fast Fourier transform process,and these signals are applied to the two tables separately.The actuators connected to different tables only need to generate large-displacement low-frequency or small-displacement high-frequency movements.The three-variable control method is used to generate large-displacement but low-frequency motion of the lower table and high-frequency but small-displacement motion of the upper table relative to the table beneath.A series of simulations are carried out using MATLAB/Simulink.The simulation results suggest that the DLST can successfully generate large-displacement high-frequency excitation.The control strategy in which the lower table tracks the low-frequency signal and the upper table tracks the original signal is recommended.
文摘High-frequency magnetic properties, such as core loss, coercivity and amplitude permeabilityof a newly-developed nanocrystalline Fe72.5Cu1Nb2V2Si13.5B9 alloy in the wide ranges of f =20-103 kHz, Bm = 0.01~0.6 T and Bmf = 10~40 (T.kHz) have been measured. A largeamount of experimental data have been fitted by a computer, thus obtaining several expressionsrepresenting the influence of frequency on high-frequency magnetic properties, that are useful inpractical applications.