BACKGROUND Fatty liver(FL) is now a worldwide disease. For decades, researchers have been kept trying to elucidate the mechanism of FL at the molecular level, but rarely involve the study of morphology and medical phy...BACKGROUND Fatty liver(FL) is now a worldwide disease. For decades, researchers have been kept trying to elucidate the mechanism of FL at the molecular level, but rarely involve the study of morphology and medical physics. Traditionally, it was believed that hemodynamic changes occur only when fibrosis occurs, but it has been proved that these changes already show in steatosis stage, which may help to reveal the pathogenesis and its progress. Because the pseudolobules are not formed during the steatosis stage, this phenomenon may be caused by the compression of the liver microcirculation and changes in the hemodynamics.AIM To understand the pathogenesis of hepatic steatosis and to study the hemodynamic changes associated with hepatic steatosis.METHODS Eight-week-old male C57 BL/6 mice were divided into three groups randomly(control group, 2-wk group, and 4-wk group), with 16 mice per group. A hepatic steatosis model was established by subcutaneous injection of carbon tetrachloride in mice. After establishing the model, liver tissue from mice was stained with hematoxylin and eosin(HE), and oil red O stains. Blood was collected from the angular vein, and hemorheological parameters were estimated. A two-photon fluorescence microscope was used to examine the flow properties of red blood cells in the hepatic sinusoids.RESULTS Oil red O staining indicated lipid accumulation in the liver after CCl_4 treatment.HE staining indicated narrowing of the hepatic sinusoidal vessels. No significant difference was observed between the 2-wk and 4-wk groups of mice onmorphological examination. Hemorheological tests included whole blood viscosity(mPas, γ = 10 s-1/γ = 100 s-1)(8.83 ± 2.22/4.69 ± 1.16, 7.73 ± 2.46/4.22 ±1.32, and 8.06 ± 2.88/4.22 ± 1.50), red blood cell volume(%)(51.00 ± 4.00, 42.00 ±5.00, and 40.00 ± 3.00), the content of plasma fibrinase(g/L)(3.80 ± 0.50, 2.90 ±0.80, and 2.30 ± 0.70), erythrocyte deformation index(%)(44.49 ± 5.81, 48.00 ±15.29, and 44.36 ± 15.01), erythrocyte electrophoresis rate(mm/s per V/m)(0.55 ±0.11, 0.50 ± 0.11, and 0.60 ± 0.20), revealing pathological changes in plasma components and red blood cells of hepatic steatosis. Assessment of blood flow velocity in the hepatic sinusoids with a laser Doppler flowmeter(mL/min per100 g)(94.43 ± 14.64, 80.00 ± 12.12, and 67.26 ± 5.92) and two-photon laser scanning microscope(μm/s)(325.68 ± 112.66, 213.53 ± 65.33, and 173.26 ± 44.02)revealed that as the modeling time increased, the blood flow velocity in the hepatic sinusoids decreased gradually, and the diameter of the hepatic sinusoids became smaller(μm)(10.28 ± 1.40, 6.84 ± 0.93, and 5.82 ± 0.79).CONCLUSION The inner diameter of the hepatic sinusoids decreases along with the decrease in the blood flow velocity within the sinusoids and the changes in the systemic hemorheology.展开更多
The liver comprises cell layers of hepatocytes called trabeculae, which are separated by vascular sinusoids. Under- standing the structure of hepatic trabeculae and liver sinusoids in hematoxylin and eosin (HE)-staine...The liver comprises cell layers of hepatocytes called trabeculae, which are separated by vascular sinusoids. Under- standing the structure of hepatic trabeculae and liver sinusoids in hematoxylin and eosin (HE)-stained liver specimens is important for the differential diagnosis of liver diseases. In this study, we develop an approach to extracting liver sinusoids from HE-stained images. The proposed approach involves: 1) a new orientation-selective filter (OS filter) for edge enhancement and image denoising, 2) the clustering of image pixels to identify candidate sinusoids, and 3) a classification procedure that discards unlikely candidates and selects the final sinusoid areas. Experimental studies using a database of 16 images with a resolution of 512 × 512 pixels showed that the proposed approach could segment liver sinusoid pixels with 81% of specificity and 94% of sensitivity. A comparison with a method based on bilateral filters showed that this method improved the sensitivity for all images with an average improvement of 4% and no difference in specificity. The results were presented to a group of pathologists and they confirmed that the images were highly representative of the tissue morphology features.展开更多
Model based implementation of a novel nonlinear adaptive filter for extraction of time varying sinusoids using Xilinx system generator has been presented in this work. The practicality of this filter model along with ...Model based implementation of a novel nonlinear adaptive filter for extraction of time varying sinusoids using Xilinx system generator has been presented in this work. The practicality of this filter model along with its performance makes it one of the foremost candidates to be applied on nonlinear systems for the purpose of estimation and extraction using reconfigurable hardware like FPGA. A design implementation and verification approach has been discussed for more efficient implementation. Timing and power analysis has been performed and the architecture has been optimized for speed and power to perform at higher frequency when integrated on a Xilinx FPGA. The proposed hardware oriented architecture has been successfully implemented and simulated. The simulation results to track a noisy input have also been shown to demonstrate the exceptional performance of the hardware based architecture developed.展开更多
Objective: To evaluate the effect of Semen Persicae combined with cultured Cordyceps on Reversing Capillarization of Sinusoids in patients with hepato-cirrhosis. Methods: Forty-four patients were treated for 3 months...Objective: To evaluate the effect of Semen Persicae combined with cultured Cordyceps on Reversing Capillarization of Sinusoids in patients with hepato-cirrhosis. Methods: Forty-four patients were treated for 3 months, the clinical and pathological effects were observed. Results: Patients were improved clinically.Pathological examination on liver biopsy of 6 patients also showed improvement in of capillarization of sinusoid,which mainly manifested by reduction of enlarged interhepatocellular spaces and collagen fiber in it, increase of lipid droplets within fat-storing cells (FSC), and decrease of proliferation of Kupffer cells. Conclusion: The combined treatment used could reverse the capillarization of sinusoid, and the mechanism might be related with its inhibition on activity and function of FSC.展开更多
BACKGROUND Portal hypertension(PH),a major complication of cirrhosis,arises from increased intrahepatic resistance and splanchnic vasodilation.Epoxyeicosatrienoic acids(EETs)improve hepatic microcirculation,but their ...BACKGROUND Portal hypertension(PH),a major complication of cirrhosis,arises from increased intrahepatic resistance and splanchnic vasodilation.Epoxyeicosatrienoic acids(EETs)improve hepatic microcirculation,but their effects are rapidly inactivated by soluble epoxide hydrolase(sEH),an enzyme upregulated in the cirrhotic liver.Inhibiting sEH increases EET levels,reducing portal pressure and fibrosis.Dipeptidyl peptidase-4 inhibitors(DPP4-Is)and angiotensin II blockers have been reported to suppress sEH and enhance EET activity.Angiotensin receptorneprilysin inhibitors(ARNIs)also lower portal pressure.However,the combined effect of DPP4-I and ARNI on the sEH-EET axis in PH and liver fibrosis remains uninvestigated.AIM To study the effects of vildagliptin,a DPP4-I and sacubitril/valsartan,an ARNI on PH and liver fibrosis in cirrhotic rats.METHODS Two rodent models of liver cirrhosis:(1)Choline-deficient,L-amino acid-defined,high-fat diet(CDAHFD)diet-fed rats;and(2)Bile duct ligation-induced rats were treated with vildagliptin(10 mg/kg/day),sacubitril/valsartan(30 mg/kg/day),or a combination of both drugs.Hemodynamic parameters,sEH activity,EET levels,vascular remodeling,and fibrosis were assessed using enzyme-linked immunosorbent assay,quantitative real-time polymerase chain reaction,Western blotting,histology,and immunofluorescence.RESULTS In CDAHFD-fed models,both DPP4-I and ARNI significantly reduced portal pressure in cirrhotic rats by decreasing intrahepatic vascular resistance without affecting systemic hemodynamics.These agents downregulated sEH expression and activity,increasing EET levels,and improved endothelial function via nitric oxide signaling enhancement.They also suppressed sinusoidal capillarization,pathological angiogenesis,and Hedgehog signaling,while restoring sinusoidal endothelial markers.Additionally,DPP4-I and ARNI attenuated liver fibrosis and stellate cell activation,reducing profibrotic gene expression.These effects were additive by the combination of both drugs.Similar effects were observed in bile duct ligation-induced PH,confirming their therapeutic potential in managing both PH and liver fibrosis through modulation of the sEH-EET pathway.CONCLUSION Combined DPP4-I with ARNI therapy ameliorates PH and fibrosis via sEH suppression and EET restoration,offering a promising treatment strategy for cirrhosis-related PH.展开更多
To enable optimal navigation for unmanned surface vehicle(USV),we proposed an adaptive hybrid strategy-based sparrow search algorithm(SSA)for efficient and reliable path planning.The proposed method began by enhancing...To enable optimal navigation for unmanned surface vehicle(USV),we proposed an adaptive hybrid strategy-based sparrow search algorithm(SSA)for efficient and reliable path planning.The proposed method began by enhancing the fitness function to comprehensively account for critical path planning metrics,including path length,turning angle,and navigation safety.To improve search diversity and effectively avoid premature convergence to local optima,chaotic mapping was employed during the population initialization stage,allowing the algorithm to explore a wider solution space from the outset.A reverse inertia weight mechanism was introduced to dynamically balance exploration and exploitation across different iterations.The adaptive adjustment of the inertia weight further improved convergence efficiency and enhanced global optimization performance.In addition,a Cauchy-Gaussian hybrid update strategy was incorporated to inject randomness and variation into the search process,which helped the algorithm escape local minima and maintain a high level of solution diversity.This approach significantly enhanced the robustness and adaptability of the optimization process.Simulation experiments confirmed that the improved SSA consistently outperformed benchmark algorithms such as the original SSA,PSO,and WMR-SSA.Compared with the three algorithms,in the simulated sea area,the path lengths of the proposed algorithm are reduced by 21%,21%,and 16%,respectively,and under the actual sea simulation conditions,the path lengths are reduced by 13%,15%,and 11%,respectively.The results highlighted the effectiveness and practicality of the proposed method,providing an effective solution for intelligent and autonomous USV navigation in complex ocean environments.展开更多
BACKGROUND Air embolism(AE)is a rare but potentially fatal complication of intestinal endoscopy(IE).CASE SUMMARY Herein,we report the case of an 18-year-old woman who underwent a successful Kasai portoenterostomy(KPE)...BACKGROUND Air embolism(AE)is a rare but potentially fatal complication of intestinal endoscopy(IE).CASE SUMMARY Herein,we report the case of an 18-year-old woman who underwent a successful Kasai portoenterostomy(KPE)for biliary atresia but died of AE during intraoperative IE for stone removal at the portoenterostomy site.Our review of the English literature identified only four similar cases of fatal AE during IE in patients undergoing KPE.The common clinical setting in the five patients,including our case,was high-pressure air insufflation into the blind closed afferent loop of the KPE to secure visibility.We hypothesize that the highly pressurized air injected into the closed loop entered the bile canaliculi—previously opened by KPE for bile drainage—passed through the tiny,microscopic pores of the fenestrated liver sinusoid endothelial cells,and finally entered the bloodstream with ease,resulting in fatal AE.CONCLUSION Meticulous performance of IE,especially on the KPE blind loop,is warranted owing to the risk of AE.展开更多
BACKGROUND The progression of non-alcoholic fatty liver disease(NAFLD)to non-alcoholic steatohepatitis(NASH)and liver fibrosis remains poorly understood,though liver sinusoidal endothelial cells(LSECs)are thought to p...BACKGROUND The progression of non-alcoholic fatty liver disease(NAFLD)to non-alcoholic steatohepatitis(NASH)and liver fibrosis remains poorly understood,though liver sinusoidal endothelial cells(LSECs)are thought to play a central role in disease pathogenesis.AIM To investigate the role of TSC22D1 in NAFLD fibrosis through its regulation of LSEC dysfunction and macrophage polarization.METHODS We analysed single-cell transcriptomic data(GSE129516)from NASH and normal INTRODUCTION Non-alcoholic fatty liver disease(NAFLD)is a global health issue associated with increasing rates of obesity and metabolic syndrome.NAFLD encompasses a spectrum of conditions,ranging from simple steatosis to more severe manifestations such as non-alcoholic steatohepatitis(NASH),fibrosis,cirrhosis,and hepatocellular carcinoma.Liver fibrosis represents a critical stage in NAFLD progression because of its strong association with impaired liver function,progression to end-stage liver disease,and increased disease-related mortality[1].The pathogenesis of NAFLD is multifactorial and involves complex interactions between genetic predispositions,insulin resistance,dietary factors,and chronic inflammation[2].Liver sinusoidal endothelial cells(LSECs),which are highly specialized endothelial cells lining the hepatic sinusoids,critically contribute to both the pathogenesis and progression of NAFLD[3,4].In NAFLD,LSECs undergo structural alterations such as reduced fenestrations,which impair hepatic microcirculation and hinder the exchange of lipids and other substances,thereby promoting lipid accumulation in hepatocytes[5].Furthermore,dysfunctional LSECs exacerbate hepatic inflammation and fibrogenesis by releasing pro-inflammatory cytokines and fibrogenic mediators,such as transforming growth factor-β(TGF-β).These factors activate hepatic stellate cells(HSCs),resulting in the pathological accumulation of extracellular matrix components[6].LSECs are also highly susceptible to oxidative stress,further aggravating hepatic injury[7,8].Importantly,LSECs influence macrophage polarization by producing chemotactic and immunomodulatory factors,thereby promoting the recruitment and activation of M1-type pro-inflammatory CONCLUSION In conclusion,this study provides a comprehensive understanding of the role of TSC22D1 in the pathogenesis of NAFLD fibrosis.We elucidated the mechanisms through which TSC22D1 drives LSEC microvascularization and EndMT,as well as its role in promoting the secretion of TWEAK,which induces macrophage polarization towards the M1 phenotype.These findings offer novel insights into the pathophysiology of NAFLD,particularly the interplay between endothelial dysfunction,inflammation,and fibrosis.Importantly,our results highlight the potential of TSC22D1 as a therapeutic target for NAFLD.Future research should focus on validating these mechanisms in human clinical cohorts and deve-loping targeted interventions,such as TSC22D1 inhibitors or modulators of the TWEAK/FN14 signalling pathway,to translate these findings into effective treatments for NAFLD progression to fibrosis.展开更多
Monitoring shear deformation of sliding zones is of great significance for understanding the landslide evolution mechanism,in which fiber optic strain sensing has shown great potential.However,the cor-relation between...Monitoring shear deformation of sliding zones is of great significance for understanding the landslide evolution mechanism,in which fiber optic strain sensing has shown great potential.However,the cor-relation between strain measurements of quasi-distributed fiber Bragg grating(FBG)sensing arrays and shear displacements of surrounding soil remains elusive.In this study,a direct shear model test was conducted to simulate the shear deformation of sliding zones,in which the soil internal deformation was captured using FBG strain sensors and the soil surface deformation was measured by particle image velocimetry(PIV).The test results show that there were two main slip surfaces and two secondary ones,developing a spindle-shaped shear band in the soil.The formation of the shear band was successfully captured by FBG sensors.A sinusoidal model was proposed to describe the fiber optic cable deformation behavior.On this basis,the shear displacements and shear band widths were calculated by using strain measurements.This work provides important insight into the deduction of soil shear deformation using soil-embedded FBG strain sensors.展开更多
A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/...A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/Al laminated composites,and the effect of sinusoidal vibration of crystallization roller on composite microstructure was investigated in detail.The results show that the metallurgical bonding of titanium and aluminum is realized by mesh interweaving and mosaic meshing,instead of transition bonding by forming metal compound layer.The meshing depth between titanium and aluminum layers (6.6μm) of cast-rolling materials with strong vibration of crystallization roller (amplitude 0.87 mm,vibration frequency 25 Hz) is doubled compared with that of traditional cast-rolling materials (3.1μm),and the composite interfacial strength(27.0 N/mm) is twice as high as that of traditional cast-rolling materials (14.9 N/mm).This is because with the action of high-speed superposition of strong tension along the rolling direction,strong pressure along the width direction and rolling force,the composite linearity evolves from "straight line" with traditional casting-rolling to "curved line",and the depth and number of cracks in the interface increases greatly compared with those with traditional cast-rolling,which leads to the deep expansion of the meshing area between interfacial layers and promotes the stable enhancement of composite quality.展开更多
Nonlinear behavior is important in the vibration test of engineering structures. In this study, a constant response vibration test is proposed for nonlinear element extraction. The method is based on the principle of ...Nonlinear behavior is important in the vibration test of engineering structures. In this study, a constant response vibration test is proposed for nonlinear element extraction. The method is based on the principle of Harmonic Balance Method (HBM). The stiffness or damping can be regarded as constant for particular steady displacement or velocity response. The displacement or velocity is controlled as a constant in the test. Then the measured Frequency Response Function(FRF) is obtained. The equivalent stiffness or damping is estimated using FRFs for a particular vibration response level. The displacement-dependent stiffness and velocity-dependent damping are fitted to describe the unknown non-linearity. The nonlinear spring and damping force can be obtained by combining the fitting results with HBM using first-order expansion. Constant response vibration test is illustrated through experimental setup to verify its effectiveness. Experimental results show that the procedure is capable of achieving an accurate parameter identification of nonlinear damping and stiffness, which is hopeful for industrial application.展开更多
BACKGROUND Neoadjuvant chemotherapy can cause hepatic sinusoidal obstruction syndrome(SOS)in patients with colorectal cancer liver metastases and increases posto-perative morbidity and mortality.AIM To evaluate T1 map...BACKGROUND Neoadjuvant chemotherapy can cause hepatic sinusoidal obstruction syndrome(SOS)in patients with colorectal cancer liver metastases and increases posto-perative morbidity and mortality.AIM To evaluate T1 mapping based on gadoxetic acid-enhanced magnetic resonance imaging(MRI)for diagnosis of hepatic SOS induced by monocrotaline.METHODS Twenty-four mice were divided into control(n=10)and experimental(n=14)groups.The experimental groups were injected with monocrotaline 2 or 6 days before MRI.MRI parameters were:T1 relaxation time before enhancement;T1 relaxation time 20 minutes after enhancement(T_(1post));a reduction in T1 relaxation time(△T_(1)%);and first enhancement slope percentage of the liver parenchyma(ESP).Albumin and bilirubin score was determined.Histological results served as a reference.Liver parenchyma samples from the control and experimental groups were analyzed by western blotting,and organic anion transporter polypeptide 1(OATP1)was measured.RESULTS T_(1post),△T_(1)%,and ESP of the liver parenchyma were significantly different between two groups(all P<0.001)and significantly correlated with the total histological score of hepatic SOS(r=-0.70,0.68 and 0.79;P<0.001).△T_(1)%and ESP were positively correlated with OATP1 levels(r=0.82,0.85;P<0.001),whereas T_(1post) had a negative correlation with OATP1 levels(r=-0.83;P<0.001).INTRODUCTION Hepatic sinusoidal obstruction syndrome(SOS)is also known as hepatic veno-occlusive disease of the liver[1].The main pathological feature of hepatic SOS is damage to liver terminal vessels,and the clinical symptoms of it include ascites and abdominal pain[2].It was first proposed in 1979 as an early complication of hematopoietic stem cell transplantation[3].The prevalence ranges from 5%to 60%,and hepatic SOS is a potentially severe complication and can even lead to death in severe cases[4].Recently,systemic neoadjuvant chemotherapy became widely regarded as one of the causes hepatic SOS in the patients with advanced metastatic colorectal cancer[5,6],especially those were treated with oxaliplatin[7,8].Oxaliplatin-based preoperative chemotherapy is used for patients with colorectal liver metastases as the standard regimen[8,9],because it could improve tumor resection outcome by shrinking the metastatic sites and reducing recurrence rate[10].Nevertheless,chemotherapy-induced hepatic SOS has been associated with a higher risk of postresection morbidity[11],such as intraoperative bleeding,intraoperative transfusions,and postoperative liver failure[12].Therefore,it is important to detect and diagnose of hepatic SOS timely.Currently,the gold standard is still based on liver biopsy[13],but it is an invasive procedure and has several limitations and complications,such as hemorrhage[14].A noninvasive diagnostic modality is needed for the assessment of hepatic SOS.Some noninvasive tools have been used for diagnosis of hepatic SOS.Researchers have utilized a preoperative platelet count and aspartate aminotransferase to platelet ratio index[15].In addition,some imaging methods such as shear wave ultrasonography,computed tomography,and gadoxetic acid-enhanced magnetic resonance imaging(MRI)have been promoted as useful methods for evaluation of hepatic SOS[16-18].Recent studies with monocrotaline(MCT)-treated rats were conducted to investigate diagnosis and prediction of severity of SOS.For example,intravoxel incoherent motion diffusion-weighted imaging,non-Gaussian diffusion models,and T1 rho quantification[19,20].The MCT-induced hepatic SOS animal model was reproducible,with a detailed pathological scoring criteria[21].Gadoxetic acid is a hepatocyte-specific contrast substance,which can provide parenchymal contrast in the hepato-biliary phase.It is reported that gadoxetic acid is absorbed into the liver parenchyma via organic anion transporter polypeptide 1(OATP1)on the hepatocyte membranes[22-24].Recently,several authors have described the feasibility of gadoxetic acid-enhanced MRI for the diagnosis of oxaliplatin-induced hepatic SOS[25].They mainly diagnosed hepatic SOS based on the signal intensity of the hepatobiliary specific phase.However,there were several limitations due to the inconsistency between signal intensity of the liver parenchyma and the concentration of contrast agent for evaluation of the degree of hepatic SOS[26].Therefore,we measured T1 relaxation time on parametric mapping because it is linearly related to the concentration of the contrast agent and is not affected by other factors[27].Yang et al[28]demonstrated T1 mapping on gadoxetic acid-enhanced MRI for the assessment of oxaliplatin-induced liver injury in a C57BL/6 mouse model.However,the main pathological changes in their model were hepatocyte degeneration and fibrosis.Therefore,we aimed to explore the effectiveness of T1 mapping based on gadoxetic acid-enhanced MRI for the diagnosis of hepatic SOS in a C57BL/6 mouse model,as well as a possible relation between OATP1 Levels and MRI parameters.展开更多
Colorectal cancer hepatic metastases represent the final stage of a multi-step biological process.This process starts with a series of mutations in colonic epithelial cells,continues with their detachment from the lar...Colorectal cancer hepatic metastases represent the final stage of a multi-step biological process.This process starts with a series of mutations in colonic epithelial cells,continues with their detachment from the large intestine,dissemination through the blood and/or lymphatic circulation,attachment to the hepatic sinusoids and interactions with the sinusoidal cells,such as sinusoidal endothelial cells,Kupffer cells,stellate cells and pit cells.The metastatic sequence terminates with colorectal cancer cell invasion,adaptation and colonisation of the hepatic parenchyma.All these events,termed the colorectal cancer invasion-metastasis cascade,include multiple molecular pathways,intercellular interactions and expression of a plethora of chemokines and growth factors,and adhesion molecules,such as the selectins,the integrins or the cadherins,as well as enzymes including matrix metalloproteinases.This review aims to present recent advances that provide insights into these cell-biological events and emphasizes those that may be amenable to therapeutic targeting.展开更多
In order to describe pavement roughness more intuitively and effectively, a method of pavement roughness simulation, i.e., the stochastic sinusoidal wave, is introduced. The method is based on the primary idea that pa...In order to describe pavement roughness more intuitively and effectively, a method of pavement roughness simulation, i.e., the stochastic sinusoidal wave, is introduced. The method is based on the primary idea that pavement roughness is denoted as the sum of numerous sines or cosines with stochastic phases, and uses the discrete spectrum to approach the target stochastic process. It is a discrete numerical method used to simulate pavement roughness. According to a given pavement power spectral density （PSD） coefficient, under the condition that the character of displacement frequency based on the time domain model is in accordance with the given pavement surface spectrum, the pavement roughness is optimized to stochastic equivalent vibrations by computer simulation, and the curves that describe pavement roughness under each grade are obtained. The results show that the stochastic sinusoidal wave is suitable for simulation of measured pavement surface spectra based on the time domain model. The method of the stochastic sinusoidal wave is important to the research on vehicle ride comfort due to its rigorous mathematical derivation, extensive application range and intuitive simulation curve. Finally, a roughness index defined as the nominal roughness index （NRI） is introduced, and it has correlation with the PSD coefficient.展开更多
白鲨优化算法是受白鲨捕猎行为的启发设计的一种新元启发式算法。该算法在求解高维优化问题时,易进入早熟状态,寻优结果精度较低。为此,文章提出一种改进的白鲨优化(improved white shake optimizer,IWSO)算法。首先使用Sinusoidal混沌...白鲨优化算法是受白鲨捕猎行为的启发设计的一种新元启发式算法。该算法在求解高维优化问题时,易进入早熟状态,寻优结果精度较低。为此,文章提出一种改进的白鲨优化(improved white shake optimizer,IWSO)算法。首先使用Sinusoidal混沌映射初始化种群,以提高种群多样性及初始解在解空间的分布性;其次,引入鸟群搜索行为,赋予白鲨游动速度自适应动态惯性权重,以提高算法的收敛速度;最后,在位置更新阶段引入精英白鲨余弦变异策略,利用余弦函数的周期性特征,驱使白鲨个体在精英白鲨的有限邻域内进行精细化开发,以提高收敛精度。在23个著名基准函数和CEC2014函数上做了性能对比实验,其结果表明,IWSO算法优于6种对比算法,适合求解函数优化问题。展开更多
Applying the atomic sparse decomposition in the distribution network with harmonics and small current grounding to decompose the transient zero sequence current that appears after the single phase to ground fault occu...Applying the atomic sparse decomposition in the distribution network with harmonics and small current grounding to decompose the transient zero sequence current that appears after the single phase to ground fault occurred. Based on dictionary of Gabor atoms and matching pursuit algorithm, the method extracts the atomic components iteratively from the feature signals and translated them to damped sinusoidal components. Then we can obtain the parametrical and analytical representation of atomic components. The termination condition of decomposing iteration is determined by the threshold of the initial residual energy with the purpose of extract the features more effectively. Accordingly, the proposed method can extract the starting and ending moment of disturbances precisely as well as their magnitudes, frequencies and other features. The numerical examples demonstrate its effectiveness.展开更多
基金Beijing Municipal Natural Science Foundation,No.7162098
文摘BACKGROUND Fatty liver(FL) is now a worldwide disease. For decades, researchers have been kept trying to elucidate the mechanism of FL at the molecular level, but rarely involve the study of morphology and medical physics. Traditionally, it was believed that hemodynamic changes occur only when fibrosis occurs, but it has been proved that these changes already show in steatosis stage, which may help to reveal the pathogenesis and its progress. Because the pseudolobules are not formed during the steatosis stage, this phenomenon may be caused by the compression of the liver microcirculation and changes in the hemodynamics.AIM To understand the pathogenesis of hepatic steatosis and to study the hemodynamic changes associated with hepatic steatosis.METHODS Eight-week-old male C57 BL/6 mice were divided into three groups randomly(control group, 2-wk group, and 4-wk group), with 16 mice per group. A hepatic steatosis model was established by subcutaneous injection of carbon tetrachloride in mice. After establishing the model, liver tissue from mice was stained with hematoxylin and eosin(HE), and oil red O stains. Blood was collected from the angular vein, and hemorheological parameters were estimated. A two-photon fluorescence microscope was used to examine the flow properties of red blood cells in the hepatic sinusoids.RESULTS Oil red O staining indicated lipid accumulation in the liver after CCl_4 treatment.HE staining indicated narrowing of the hepatic sinusoidal vessels. No significant difference was observed between the 2-wk and 4-wk groups of mice onmorphological examination. Hemorheological tests included whole blood viscosity(mPas, γ = 10 s-1/γ = 100 s-1)(8.83 ± 2.22/4.69 ± 1.16, 7.73 ± 2.46/4.22 ±1.32, and 8.06 ± 2.88/4.22 ± 1.50), red blood cell volume(%)(51.00 ± 4.00, 42.00 ±5.00, and 40.00 ± 3.00), the content of plasma fibrinase(g/L)(3.80 ± 0.50, 2.90 ±0.80, and 2.30 ± 0.70), erythrocyte deformation index(%)(44.49 ± 5.81, 48.00 ±15.29, and 44.36 ± 15.01), erythrocyte electrophoresis rate(mm/s per V/m)(0.55 ±0.11, 0.50 ± 0.11, and 0.60 ± 0.20), revealing pathological changes in plasma components and red blood cells of hepatic steatosis. Assessment of blood flow velocity in the hepatic sinusoids with a laser Doppler flowmeter(mL/min per100 g)(94.43 ± 14.64, 80.00 ± 12.12, and 67.26 ± 5.92) and two-photon laser scanning microscope(μm/s)(325.68 ± 112.66, 213.53 ± 65.33, and 173.26 ± 44.02)revealed that as the modeling time increased, the blood flow velocity in the hepatic sinusoids decreased gradually, and the diameter of the hepatic sinusoids became smaller(μm)(10.28 ± 1.40, 6.84 ± 0.93, and 5.82 ± 0.79).CONCLUSION The inner diameter of the hepatic sinusoids decreases along with the decrease in the blood flow velocity within the sinusoids and the changes in the systemic hemorheology.
文摘The liver comprises cell layers of hepatocytes called trabeculae, which are separated by vascular sinusoids. Under- standing the structure of hepatic trabeculae and liver sinusoids in hematoxylin and eosin (HE)-stained liver specimens is important for the differential diagnosis of liver diseases. In this study, we develop an approach to extracting liver sinusoids from HE-stained images. The proposed approach involves: 1) a new orientation-selective filter (OS filter) for edge enhancement and image denoising, 2) the clustering of image pixels to identify candidate sinusoids, and 3) a classification procedure that discards unlikely candidates and selects the final sinusoid areas. Experimental studies using a database of 16 images with a resolution of 512 × 512 pixels showed that the proposed approach could segment liver sinusoid pixels with 81% of specificity and 94% of sensitivity. A comparison with a method based on bilateral filters showed that this method improved the sensitivity for all images with an average improvement of 4% and no difference in specificity. The results were presented to a group of pathologists and they confirmed that the images were highly representative of the tissue morphology features.
文摘Model based implementation of a novel nonlinear adaptive filter for extraction of time varying sinusoids using Xilinx system generator has been presented in this work. The practicality of this filter model along with its performance makes it one of the foremost candidates to be applied on nonlinear systems for the purpose of estimation and extraction using reconfigurable hardware like FPGA. A design implementation and verification approach has been discussed for more efficient implementation. Timing and power analysis has been performed and the architecture has been optimized for speed and power to perform at higher frequency when integrated on a Xilinx FPGA. The proposed hardware oriented architecture has been successfully implemented and simulated. The simulation results to track a noisy input have also been shown to demonstrate the exceptional performance of the hardware based architecture developed.
文摘Objective: To evaluate the effect of Semen Persicae combined with cultured Cordyceps on Reversing Capillarization of Sinusoids in patients with hepato-cirrhosis. Methods: Forty-four patients were treated for 3 months, the clinical and pathological effects were observed. Results: Patients were improved clinically.Pathological examination on liver biopsy of 6 patients also showed improvement in of capillarization of sinusoid,which mainly manifested by reduction of enlarged interhepatocellular spaces and collagen fiber in it, increase of lipid droplets within fat-storing cells (FSC), and decrease of proliferation of Kupffer cells. Conclusion: The combined treatment used could reverse the capillarization of sinusoid, and the mechanism might be related with its inhibition on activity and function of FSC.
文摘BACKGROUND Portal hypertension(PH),a major complication of cirrhosis,arises from increased intrahepatic resistance and splanchnic vasodilation.Epoxyeicosatrienoic acids(EETs)improve hepatic microcirculation,but their effects are rapidly inactivated by soluble epoxide hydrolase(sEH),an enzyme upregulated in the cirrhotic liver.Inhibiting sEH increases EET levels,reducing portal pressure and fibrosis.Dipeptidyl peptidase-4 inhibitors(DPP4-Is)and angiotensin II blockers have been reported to suppress sEH and enhance EET activity.Angiotensin receptorneprilysin inhibitors(ARNIs)also lower portal pressure.However,the combined effect of DPP4-I and ARNI on the sEH-EET axis in PH and liver fibrosis remains uninvestigated.AIM To study the effects of vildagliptin,a DPP4-I and sacubitril/valsartan,an ARNI on PH and liver fibrosis in cirrhotic rats.METHODS Two rodent models of liver cirrhosis:(1)Choline-deficient,L-amino acid-defined,high-fat diet(CDAHFD)diet-fed rats;and(2)Bile duct ligation-induced rats were treated with vildagliptin(10 mg/kg/day),sacubitril/valsartan(30 mg/kg/day),or a combination of both drugs.Hemodynamic parameters,sEH activity,EET levels,vascular remodeling,and fibrosis were assessed using enzyme-linked immunosorbent assay,quantitative real-time polymerase chain reaction,Western blotting,histology,and immunofluorescence.RESULTS In CDAHFD-fed models,both DPP4-I and ARNI significantly reduced portal pressure in cirrhotic rats by decreasing intrahepatic vascular resistance without affecting systemic hemodynamics.These agents downregulated sEH expression and activity,increasing EET levels,and improved endothelial function via nitric oxide signaling enhancement.They also suppressed sinusoidal capillarization,pathological angiogenesis,and Hedgehog signaling,while restoring sinusoidal endothelial markers.Additionally,DPP4-I and ARNI attenuated liver fibrosis and stellate cell activation,reducing profibrotic gene expression.These effects were additive by the combination of both drugs.Similar effects were observed in bile duct ligation-induced PH,confirming their therapeutic potential in managing both PH and liver fibrosis through modulation of the sEH-EET pathway.CONCLUSION Combined DPP4-I with ARNI therapy ameliorates PH and fibrosis via sEH suppression and EET restoration,offering a promising treatment strategy for cirrhosis-related PH.
基金supported by Shandong Provincial Department of Science and Technology Project(No.2022C01246)National Undergraduate Innovation Training Project(Nos.202410390028,202310390026)+1 种基金Fujian Provincial Undergraduate Innovation Training Project(No.202410390093)Jimei University Innovation Training Project(Nos.2024xj224,2023xj179).
文摘To enable optimal navigation for unmanned surface vehicle(USV),we proposed an adaptive hybrid strategy-based sparrow search algorithm(SSA)for efficient and reliable path planning.The proposed method began by enhancing the fitness function to comprehensively account for critical path planning metrics,including path length,turning angle,and navigation safety.To improve search diversity and effectively avoid premature convergence to local optima,chaotic mapping was employed during the population initialization stage,allowing the algorithm to explore a wider solution space from the outset.A reverse inertia weight mechanism was introduced to dynamically balance exploration and exploitation across different iterations.The adaptive adjustment of the inertia weight further improved convergence efficiency and enhanced global optimization performance.In addition,a Cauchy-Gaussian hybrid update strategy was incorporated to inject randomness and variation into the search process,which helped the algorithm escape local minima and maintain a high level of solution diversity.This approach significantly enhanced the robustness and adaptability of the optimization process.Simulation experiments confirmed that the improved SSA consistently outperformed benchmark algorithms such as the original SSA,PSO,and WMR-SSA.Compared with the three algorithms,in the simulated sea area,the path lengths of the proposed algorithm are reduced by 21%,21%,and 16%,respectively,and under the actual sea simulation conditions,the path lengths are reduced by 13%,15%,and 11%,respectively.The results highlighted the effectiveness and practicality of the proposed method,providing an effective solution for intelligent and autonomous USV navigation in complex ocean environments.
文摘BACKGROUND Air embolism(AE)is a rare but potentially fatal complication of intestinal endoscopy(IE).CASE SUMMARY Herein,we report the case of an 18-year-old woman who underwent a successful Kasai portoenterostomy(KPE)for biliary atresia but died of AE during intraoperative IE for stone removal at the portoenterostomy site.Our review of the English literature identified only four similar cases of fatal AE during IE in patients undergoing KPE.The common clinical setting in the five patients,including our case,was high-pressure air insufflation into the blind closed afferent loop of the KPE to secure visibility.We hypothesize that the highly pressurized air injected into the closed loop entered the bile canaliculi—previously opened by KPE for bile drainage—passed through the tiny,microscopic pores of the fenestrated liver sinusoid endothelial cells,and finally entered the bloodstream with ease,resulting in fatal AE.CONCLUSION Meticulous performance of IE,especially on the KPE blind loop,is warranted owing to the risk of AE.
基金Supported by the Changzhou Science and Techology Program,No.CJ20241048Changzhou High-Level Medical Talents Training Project,No.2022CZBJ105+1 种基金Development Foundation of the Affiliated Hospital of Xuzhou Medical University,No.XYFC202304 and No.XYFM202307The Open Project of Jiangsu Provincial Key Laboratory of Laboratory Medicine,No.JSKLM-Z-2024-002.
文摘BACKGROUND The progression of non-alcoholic fatty liver disease(NAFLD)to non-alcoholic steatohepatitis(NASH)and liver fibrosis remains poorly understood,though liver sinusoidal endothelial cells(LSECs)are thought to play a central role in disease pathogenesis.AIM To investigate the role of TSC22D1 in NAFLD fibrosis through its regulation of LSEC dysfunction and macrophage polarization.METHODS We analysed single-cell transcriptomic data(GSE129516)from NASH and normal INTRODUCTION Non-alcoholic fatty liver disease(NAFLD)is a global health issue associated with increasing rates of obesity and metabolic syndrome.NAFLD encompasses a spectrum of conditions,ranging from simple steatosis to more severe manifestations such as non-alcoholic steatohepatitis(NASH),fibrosis,cirrhosis,and hepatocellular carcinoma.Liver fibrosis represents a critical stage in NAFLD progression because of its strong association with impaired liver function,progression to end-stage liver disease,and increased disease-related mortality[1].The pathogenesis of NAFLD is multifactorial and involves complex interactions between genetic predispositions,insulin resistance,dietary factors,and chronic inflammation[2].Liver sinusoidal endothelial cells(LSECs),which are highly specialized endothelial cells lining the hepatic sinusoids,critically contribute to both the pathogenesis and progression of NAFLD[3,4].In NAFLD,LSECs undergo structural alterations such as reduced fenestrations,which impair hepatic microcirculation and hinder the exchange of lipids and other substances,thereby promoting lipid accumulation in hepatocytes[5].Furthermore,dysfunctional LSECs exacerbate hepatic inflammation and fibrogenesis by releasing pro-inflammatory cytokines and fibrogenic mediators,such as transforming growth factor-β(TGF-β).These factors activate hepatic stellate cells(HSCs),resulting in the pathological accumulation of extracellular matrix components[6].LSECs are also highly susceptible to oxidative stress,further aggravating hepatic injury[7,8].Importantly,LSECs influence macrophage polarization by producing chemotactic and immunomodulatory factors,thereby promoting the recruitment and activation of M1-type pro-inflammatory CONCLUSION In conclusion,this study provides a comprehensive understanding of the role of TSC22D1 in the pathogenesis of NAFLD fibrosis.We elucidated the mechanisms through which TSC22D1 drives LSEC microvascularization and EndMT,as well as its role in promoting the secretion of TWEAK,which induces macrophage polarization towards the M1 phenotype.These findings offer novel insights into the pathophysiology of NAFLD,particularly the interplay between endothelial dysfunction,inflammation,and fibrosis.Importantly,our results highlight the potential of TSC22D1 as a therapeutic target for NAFLD.Future research should focus on validating these mechanisms in human clinical cohorts and deve-loping targeted interventions,such as TSC22D1 inhibitors or modulators of the TWEAK/FN14 signalling pathway,to translate these findings into effective treatments for NAFLD progression to fibrosis.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.42225702 and 42077235)the Open Research Project Program of the State Key Laboratory of Internet of Things for Smart City(University of Macao)(Grant No.SKL-IoTSC(UM)-2021-2023/ORP/GA10/2022)。
文摘Monitoring shear deformation of sliding zones is of great significance for understanding the landslide evolution mechanism,in which fiber optic strain sensing has shown great potential.However,the cor-relation between strain measurements of quasi-distributed fiber Bragg grating(FBG)sensing arrays and shear displacements of surrounding soil remains elusive.In this study,a direct shear model test was conducted to simulate the shear deformation of sliding zones,in which the soil internal deformation was captured using FBG strain sensors and the soil surface deformation was measured by particle image velocimetry(PIV).The test results show that there were two main slip surfaces and two secondary ones,developing a spindle-shaped shear band in the soil.The formation of the shear band was successfully captured by FBG sensors.A sinusoidal model was proposed to describe the fiber optic cable deformation behavior.On this basis,the shear displacements and shear band widths were calculated by using strain measurements.This work provides important insight into the deduction of soil shear deformation using soil-embedded FBG strain sensors.
基金Funded by the Hebei Province Natural Science Foundation (No.E2017203043)National Natural Science Foundation of China(No.U1604251)。
文摘A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/Al laminated composites,and the effect of sinusoidal vibration of crystallization roller on composite microstructure was investigated in detail.The results show that the metallurgical bonding of titanium and aluminum is realized by mesh interweaving and mosaic meshing,instead of transition bonding by forming metal compound layer.The meshing depth between titanium and aluminum layers (6.6μm) of cast-rolling materials with strong vibration of crystallization roller (amplitude 0.87 mm,vibration frequency 25 Hz) is doubled compared with that of traditional cast-rolling materials (3.1μm),and the composite interfacial strength(27.0 N/mm) is twice as high as that of traditional cast-rolling materials (14.9 N/mm).This is because with the action of high-speed superposition of strong tension along the rolling direction,strong pressure along the width direction and rolling force,the composite linearity evolves from "straight line" with traditional casting-rolling to "curved line",and the depth and number of cracks in the interface increases greatly compared with those with traditional cast-rolling,which leads to the deep expansion of the meshing area between interfacial layers and promotes the stable enhancement of composite quality.
文摘Nonlinear behavior is important in the vibration test of engineering structures. In this study, a constant response vibration test is proposed for nonlinear element extraction. The method is based on the principle of Harmonic Balance Method (HBM). The stiffness or damping can be regarded as constant for particular steady displacement or velocity response. The displacement or velocity is controlled as a constant in the test. Then the measured Frequency Response Function(FRF) is obtained. The equivalent stiffness or damping is estimated using FRFs for a particular vibration response level. The displacement-dependent stiffness and velocity-dependent damping are fitted to describe the unknown non-linearity. The nonlinear spring and damping force can be obtained by combining the fitting results with HBM using first-order expansion. Constant response vibration test is illustrated through experimental setup to verify its effectiveness. Experimental results show that the procedure is capable of achieving an accurate parameter identification of nonlinear damping and stiffness, which is hopeful for industrial application.
基金the National Science Foundation for Young Scientists of China,No.81701682.
文摘BACKGROUND Neoadjuvant chemotherapy can cause hepatic sinusoidal obstruction syndrome(SOS)in patients with colorectal cancer liver metastases and increases posto-perative morbidity and mortality.AIM To evaluate T1 mapping based on gadoxetic acid-enhanced magnetic resonance imaging(MRI)for diagnosis of hepatic SOS induced by monocrotaline.METHODS Twenty-four mice were divided into control(n=10)and experimental(n=14)groups.The experimental groups were injected with monocrotaline 2 or 6 days before MRI.MRI parameters were:T1 relaxation time before enhancement;T1 relaxation time 20 minutes after enhancement(T_(1post));a reduction in T1 relaxation time(△T_(1)%);and first enhancement slope percentage of the liver parenchyma(ESP).Albumin and bilirubin score was determined.Histological results served as a reference.Liver parenchyma samples from the control and experimental groups were analyzed by western blotting,and organic anion transporter polypeptide 1(OATP1)was measured.RESULTS T_(1post),△T_(1)%,and ESP of the liver parenchyma were significantly different between two groups(all P<0.001)and significantly correlated with the total histological score of hepatic SOS(r=-0.70,0.68 and 0.79;P<0.001).△T_(1)%and ESP were positively correlated with OATP1 levels(r=0.82,0.85;P<0.001),whereas T_(1post) had a negative correlation with OATP1 levels(r=-0.83;P<0.001).INTRODUCTION Hepatic sinusoidal obstruction syndrome(SOS)is also known as hepatic veno-occlusive disease of the liver[1].The main pathological feature of hepatic SOS is damage to liver terminal vessels,and the clinical symptoms of it include ascites and abdominal pain[2].It was first proposed in 1979 as an early complication of hematopoietic stem cell transplantation[3].The prevalence ranges from 5%to 60%,and hepatic SOS is a potentially severe complication and can even lead to death in severe cases[4].Recently,systemic neoadjuvant chemotherapy became widely regarded as one of the causes hepatic SOS in the patients with advanced metastatic colorectal cancer[5,6],especially those were treated with oxaliplatin[7,8].Oxaliplatin-based preoperative chemotherapy is used for patients with colorectal liver metastases as the standard regimen[8,9],because it could improve tumor resection outcome by shrinking the metastatic sites and reducing recurrence rate[10].Nevertheless,chemotherapy-induced hepatic SOS has been associated with a higher risk of postresection morbidity[11],such as intraoperative bleeding,intraoperative transfusions,and postoperative liver failure[12].Therefore,it is important to detect and diagnose of hepatic SOS timely.Currently,the gold standard is still based on liver biopsy[13],but it is an invasive procedure and has several limitations and complications,such as hemorrhage[14].A noninvasive diagnostic modality is needed for the assessment of hepatic SOS.Some noninvasive tools have been used for diagnosis of hepatic SOS.Researchers have utilized a preoperative platelet count and aspartate aminotransferase to platelet ratio index[15].In addition,some imaging methods such as shear wave ultrasonography,computed tomography,and gadoxetic acid-enhanced magnetic resonance imaging(MRI)have been promoted as useful methods for evaluation of hepatic SOS[16-18].Recent studies with monocrotaline(MCT)-treated rats were conducted to investigate diagnosis and prediction of severity of SOS.For example,intravoxel incoherent motion diffusion-weighted imaging,non-Gaussian diffusion models,and T1 rho quantification[19,20].The MCT-induced hepatic SOS animal model was reproducible,with a detailed pathological scoring criteria[21].Gadoxetic acid is a hepatocyte-specific contrast substance,which can provide parenchymal contrast in the hepato-biliary phase.It is reported that gadoxetic acid is absorbed into the liver parenchyma via organic anion transporter polypeptide 1(OATP1)on the hepatocyte membranes[22-24].Recently,several authors have described the feasibility of gadoxetic acid-enhanced MRI for the diagnosis of oxaliplatin-induced hepatic SOS[25].They mainly diagnosed hepatic SOS based on the signal intensity of the hepatobiliary specific phase.However,there were several limitations due to the inconsistency between signal intensity of the liver parenchyma and the concentration of contrast agent for evaluation of the degree of hepatic SOS[26].Therefore,we measured T1 relaxation time on parametric mapping because it is linearly related to the concentration of the contrast agent and is not affected by other factors[27].Yang et al[28]demonstrated T1 mapping on gadoxetic acid-enhanced MRI for the assessment of oxaliplatin-induced liver injury in a C57BL/6 mouse model.However,the main pathological changes in their model were hepatocyte degeneration and fibrosis.Therefore,we aimed to explore the effectiveness of T1 mapping based on gadoxetic acid-enhanced MRI for the diagnosis of hepatic SOS in a C57BL/6 mouse model,as well as a possible relation between OATP1 Levels and MRI parameters.
文摘Colorectal cancer hepatic metastases represent the final stage of a multi-step biological process.This process starts with a series of mutations in colonic epithelial cells,continues with their detachment from the large intestine,dissemination through the blood and/or lymphatic circulation,attachment to the hepatic sinusoids and interactions with the sinusoidal cells,such as sinusoidal endothelial cells,Kupffer cells,stellate cells and pit cells.The metastatic sequence terminates with colorectal cancer cell invasion,adaptation and colonisation of the hepatic parenchyma.All these events,termed the colorectal cancer invasion-metastasis cascade,include multiple molecular pathways,intercellular interactions and expression of a plethora of chemokines and growth factors,and adhesion molecules,such as the selectins,the integrins or the cadherins,as well as enzymes including matrix metalloproteinases.This review aims to present recent advances that provide insights into these cell-biological events and emphasizes those that may be amenable to therapeutic targeting.
文摘In order to describe pavement roughness more intuitively and effectively, a method of pavement roughness simulation, i.e., the stochastic sinusoidal wave, is introduced. The method is based on the primary idea that pavement roughness is denoted as the sum of numerous sines or cosines with stochastic phases, and uses the discrete spectrum to approach the target stochastic process. It is a discrete numerical method used to simulate pavement roughness. According to a given pavement power spectral density （PSD） coefficient, under the condition that the character of displacement frequency based on the time domain model is in accordance with the given pavement surface spectrum, the pavement roughness is optimized to stochastic equivalent vibrations by computer simulation, and the curves that describe pavement roughness under each grade are obtained. The results show that the stochastic sinusoidal wave is suitable for simulation of measured pavement surface spectra based on the time domain model. The method of the stochastic sinusoidal wave is important to the research on vehicle ride comfort due to its rigorous mathematical derivation, extensive application range and intuitive simulation curve. Finally, a roughness index defined as the nominal roughness index （NRI） is introduced, and it has correlation with the PSD coefficient.
文摘白鲨优化算法是受白鲨捕猎行为的启发设计的一种新元启发式算法。该算法在求解高维优化问题时,易进入早熟状态,寻优结果精度较低。为此,文章提出一种改进的白鲨优化(improved white shake optimizer,IWSO)算法。首先使用Sinusoidal混沌映射初始化种群,以提高种群多样性及初始解在解空间的分布性;其次,引入鸟群搜索行为,赋予白鲨游动速度自适应动态惯性权重,以提高算法的收敛速度;最后,在位置更新阶段引入精英白鲨余弦变异策略,利用余弦函数的周期性特征,驱使白鲨个体在精英白鲨的有限邻域内进行精细化开发,以提高收敛精度。在23个著名基准函数和CEC2014函数上做了性能对比实验,其结果表明,IWSO算法优于6种对比算法,适合求解函数优化问题。
文摘Applying the atomic sparse decomposition in the distribution network with harmonics and small current grounding to decompose the transient zero sequence current that appears after the single phase to ground fault occurred. Based on dictionary of Gabor atoms and matching pursuit algorithm, the method extracts the atomic components iteratively from the feature signals and translated them to damped sinusoidal components. Then we can obtain the parametrical and analytical representation of atomic components. The termination condition of decomposing iteration is determined by the threshold of the initial residual energy with the purpose of extract the features more effectively. Accordingly, the proposed method can extract the starting and ending moment of disturbances precisely as well as their magnitudes, frequencies and other features. The numerical examples demonstrate its effectiveness.
