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| 1 | 为弥漫的甲状腺腺病理的评估的 ARFI elastography : 初步的结果显示文摘 AIM:To assess whether acoustic radiation force impulse(ARFI)elastography can differentiate normal from pathological thyroid parenchyma.METHODS:We evaluated 136 subjects(mean age 45.8±15.6 years,106 women and 30 men):44(32.3%) without thyroid pathology,48(35.3%)with BasedowGraves’disease(GD),37(27.2%)with chronic autoimmune thyroiditis(CAT;diagnosed by specific tests),4(2.9%)with diffuse thyroid goiter and 3(2.2%)cases with thyroid pathology induced by amiodarone.In all patients,10 elastographic measurements were made in the right thyroid lobe and 10 in the left thyroid lobe,using a 1-4.5 MHZ convex probe and a 4-9 MHz linear probe,respectively.Median values were calculated for thyroid stiffness and expressed in meters/second(m/s).RESULTS:Thyroid stiffness(TS)assessed by means of ARFI in healthy subjects(2±0.40 m/s)was significantly lower than in GD(2.67±0.53 m/s)(P<0.0001) and CAT patients(2.43±0.58 m/s)(P=0.0002),but the differences were not significant between GDvs CAT patients(P=0.053).The optimal cut-off value for the prediction of diffuse thyroid pathology was 2.36 m/s.For this cut-off value,TS had 62.5%sensitivity,79.5% specificity,87.6%predictive positive value,55.5% negative predictive value and 72.7%accuracy for the presence of diffuse thyroid gland pathology(AUROC=0.804).There were no significant differences between the TS values obtained with linear vs convex probes and when 5 vs 10 measurements were taken in each lobe(median values).CONCLUSION:ARFI seems to be a useful method for the assessment of diffuse thyroid gland pathology. | Ioan Sporea Roxana Sirli Simona Bota Mihaela Vlad Alina Popescu Ioana Zosin | 2012 | World Journal of Radiology2012，4，4： | 25 |
| 2 | Is ARFI elastography reliable for predicting fibrosis severity in chronic HCV hepatitis?显示文摘AIM:To determine whether acoustic radiation force impulse(ARFI) elastography is a reliable method for predicting fibrosis severity in patients with chronic hepatitis C virus(HCV) hepatitis.METHODS:We performed a multicenter study including 274 subjects with HCV chronic hepatitis in which we compared ARFI with liver biopsy(LB).In each patient we performed LB(evaluated according to the Metavir score) and ARFI measurements(using a Siemens Acuson S2000TM ultrasound system:10 valid measurements were performed and median values were calculated and expressed in meters/second(m/s).RESULTS:A direct,strong,correlation(Spearman r = 0.707) was found between ARFI measurements and fibrosis(P < 0.0001).For predicting the presence of fibrosis(F ≥ 1 Metavir),significant fibrosis(F ≥ 2),severe fibrosis(F ≥ 3) and cirrhosis(F = 4),the cutoff values of 1.19,1.21,1.58 and 1.82 m/s were determined,respectively,liver stiffness measurements had 73%,84%,84% and 91% Se respectively;93%,91%,94%,90% Sp,respectively;with AUROCs of 0.880,0.893,0.908 and 0.937,respectively.CONCLUSION:ARFI measurement is a reliable method for predicting the severity of fibrosis in HCV | Ioan Sporea Roxana Sirli Simona Bota Carmen Fierbinteanu-Braticevici Alina Popescu Radu Badea Monica Lupsor Ana Petrisor Mirela Dnil | 2011 | World Journal of Radiology2011，3，7： | 24 |
| 3 | Effect of alcohol consumption on liver stiffness measured by transient elastography显示文摘AIM:To determine the evolution of transient elastography(TE) in patients with alcoholic liver disease according to alcohol cessation or continuation.METHODS:We retrospectively selected in our local database all patients who had two TE between June 2005 and November 2010 with chronic alcohol excessive consumption and excluded those with associated cause of liver disease.TE was performed at least one week apart by senior operator.TE examinations with less than ten successful measures or with an interquartile range above 30% were excluded.We retrospectively reviewed file of all patients to include only patient followed up by trained addictologist and for which definite information on alcohol consumption was available.Concomitant biological parameters [aspartate amino transferase(AST),alanine amino transferase and gamma-glutamyl transpeptidase(GGT)] within 4 wk of initial and final TE were recorded.Putative fibrosis score according to initial and final TE were determined with available cut-off for alcoholic liver disease and hepatitis C.Initial and final putative fibrosis score were compared according to alcohol consumption during follow-up.RESULTS:During the study period 572 patients had TE examination for alcoholic liver disease and 79 of them had at least two examinations.Thirty-seven patients met our criteria with a median follow-up of 32.5 wk.At the end of the study,13(35%) were abstinent,and 24(65%) relapsers.Eight patients had liver biopsy during follow-up.TE decreased significantly during follow-up in 85% of abstinent patients [median(range):-4.9(-6.1,-1.9)],leading to a modification of the putative fibrosis stage in 28%-71% of patient according to different cut-off value.In relapsers TE increased in 45% and decreased in 54% of patient.There was no statistical difference between initial and final TE in relapsers.In the overall population,using 22.6 kPa as cut-off for cirrhosis,4 patients had cirrhosis at initial TE and 3 patients had cirrhosis at final TE.Using 19.5 kPa as cut-off for cirrhosis,7 patients had cirrhosis at initial TE and 5 patients had cirrhosis at final TE.Using 12.5 kPa as cut-off for cirrhosis,16 patients had cirrhosis at initial TE and 15 patients had cirrhosis at final TE.Evolution of biological data was in accordance with the relapse or abstinent status:abstinence ratio(duration of abstinence/duration follow-up) was correlated with AST ratio(r =-0.465,P = 0.007) and GGT ratio(r =-0.662,P<0.0001).GGT was correlated with initial(r = 0.488,P = 0.002) and final TE(r = 0.49,P<0.005).Final TE was correlated with AST(r = 0.362,P<0.05).Correlation between TE ratio and AST ratio(r = 0.44,P = 0.01) revealed that TE varied proportionally to AST for all patients irrespective of their alcohol status.The same relationship was observed between TE ratio and GGT ratio(r = 0.65,P<0.0001).Evolution of TE was significantly correlated with the ratio of time of abstinence to observation time(r =-0.387,P = 0.016) and the evolution of liver enzymes.CONCLUSION:TE significantly decreased with abstinence.Results of TE in alcoholic liver disease cannot be interpreted without taking into account alcohol consumption and liver enzymes. | Edouard Bardou-Jacquet Ludivine Legros Draman Soro Marianne Latournerie Anne Guillygomarc'h Caroline Le Lan Pierre Brissot Dominique Guyader Romain Moirand | 2013 | World Journal of Gastroenterology2013，19，4： | 20 |
| 4 | Elastography-based screening for esophageal varices in patients with advanced chronic liver disease显示文摘Elastography-based liver stiffness measurement(LSM) is a non-invasive tool for estimating liver fibrosis but also provides an estimate for the severity of portal hypertension in patients with advanced chronic liver disease(ACLD). The presence of varices and especially of varices needing treatment(VNT) indicates distinct prognostic stages in patients with compensated ACLD(cACLD). The Baveno VI guidelines suggested a simple algorithm based on LSM < 20 kPa(by transient elastography, TE) and platelet count > 150 G/L for ruling-out VNT in patients with cACLD. These(and other) TE-based LSM cut-offs have been evaluated for VNT screening in different liver disease etiologies. Novel point shear-wave elastography(pSWE) and two-dimensional shear wave elastography(2D-SWE) methodologies for LSM have also been evaluated for their ability to screen for 'any' varices and for VNT. Finally, the measurement of spleen stiffness(SSM) by elastography(mainly by pSWE and 2D-SWE) may represent another valuable screening tool for varices. Here, we summarize the current literature on elastography-based prediction of 'any' varices and VNT. Finally,we have summarized the published LSM and SSM cut-offs in clinically useful scale cards. | Rafael Paternostro Thomas Reiberger Theresa Bucsics | 2019 | World Journal of Gastroenterology2019，25，3： | 20 |
| 5 | Management of small hepatocellular carcinoma in cirrhosis:Focus on portal hypertension显示文摘The incidence of hepatocellular carcinoma(HCC) is rising worldwide being currently the fifth most common cancer and third cause of cancer-related mortality.Early detection of HCC through surveillance programs have enabled the identification of small nodules with higher frequency,and nowadays account for 10%-15% of patients diagnosed in the West and almost 30% in Japan.Patients with small HCC can be candidates for potential curative treatments:liver transplantation,surgical resection and percutaneous ablation,depending on the presence of portal hypertension and co-morbidities.This review will analyze recent advancements in the clinical management of these individuals,focusing on issues related to the role of portal hypertension,the debate between resection and ablative therapies and the future impact of molecular technologies. | Virginia Hernandez-Gea Fanny Turon Annalisa Berzigotti Augusto Villanueva | 2013 | World Journal of Gastroenterology2013，19，8： | 20 |
| 6 | Real time shear wave elastography in chronic liver diseases:Accuracy for predicting liver fibrosis,in comparison with serum markers显示文摘AIM:To evaluate the correlation between liver stiffness measurement(LSM)by real-time shear wave elastography(SWE)and liver fibrosis stage and the accuracy of LSM for predicting significant and advanced fibrosis,in comparison with serum markers.METHODS:We consecutively analyzed 70 patients with various chronic liver diseases.Liver fibrosis was staged from F0 to F4 according to the Batts and Ludwig scoring system.Significant and advanced fibrosis was defined as stage F≥2 and F≥3,respectively.The accuracy of prediction for fibrosis was analyzed using receiver operating characteristic curves.RESULTS:Seventy patients,15 were belonged to F0-F1 stage,20 F2,13 F3 and 22 F4.LSM was increased with progression of fibrosis stage(F0-F1:6.77±1.72,F2:9.98±3.99,F3:15.80±7.73,and F4:22.09±10.09,P<0.001).Diagnostic accuracies of LSM for prediction of F≥2 and F≥3 were 0.915(95%CI:0.824-0.968,P<0.001)and 0.913(95%CI:0.821-0.967,P<0.001),respectively.The cut-off values of LSM for prediction of F≥2 and F≥3 were 8.6kPa with 78.2%sensitivity and 93.3%specificity and10.46 kPa with 88.6%sensitivity and 80.0%specificity,respectively.However,there were no significant differences between LSM and serum hyaluronic acid and typeⅣcollagen in diagnostic accuracy.CONCLUSION:SWE showed a significant correlation with the severity of liver fibrosis and was useful and accurate to predict significant and advanced fibrosis,comparable with serum markers. | Jae Yoon Jeong Tae Yeob Kim Joo Hyun Sohn Yongsoo Kim Woo Kyoung Jeong Young-Ha Oh Kyo-Sang Yoo | 2014 | World Journal of Gastroenterology2014，20，38： | 19 |
| 7 | Mobile-robotic machining for large complex components:A review study显示文摘Even though the robotic machining has achieved great success in machining of small components, it lacks the competence to machine large complex components, such as wind turbine blade, train carriage, and aircraft wing. In order to cope with this issue,the mobile machining robot system, which consists of a robot arm integrated with a mobile platform, is proposed to achieve the large workspace and high dexterity, and thus has the potential to machine the large complex components. However, due to the limitation of motion accuracy and structural stiffness, the current mobile-robots are hard to satisfy the high precision requirement of machining tasks. In this paper, some historical mobile-robotic machining systems are reviewed firstly, followed by some key techniques related to structure optimization, dynamics of the machining process, localization, and control techniques, which are fundamental for the structural stiffness and motion accuracy of mobile-robots. Finally, the prospect of mobile-robotic machining and the open questions are addressed. | TAO Bo ZHAO XingWei DING Han | 2019 | Science China(Technological Sciences)2019，62，8： | 17 |
| 8 | Noninvasive Measurement of Liver Fibrosis by Transient Elastography and Influencing Factors in Patients with Chronic Hepatitis B―A Single Center Retrospective Study of 466 Patients显示文摘The noninvasive measurement of liver stiffness (LS) was evaluated by transient elastogra-phy (FibroScan) and the possible influencing factors from the patients' clinical situations including age,gender,liver inflammation represented by alanine transaminase (ALT) and total billirubin (TBIL) level,HBV replication (HBV DNA loads),portal vein pressure (portal vessel diameter,PVD),splenic thick-ness (SPT) and body mass index (BMI) were analyzed in patients with chronic hepatitis B (CHB).A to-tal of 466 patients including 31 patients with acute-on-chronic liver failure (ACLF),and 435 patients with chronic hepatitis B (CHB) among which 82 patients were diagnosed with liver cirrhosis (LC) by clinical manifestations and liver B-type ultrasonic inspection were enrolled at Tongji Hospital from April to December 2009.LS was measured by a FibroScan device (EchoSens,France).Simultaneously,ALT and TBIL levels,HBV DNA loads,PVD,SPT and BMI in all patients were also tested.Forty-one healthy volunteers served as controls.The values of LS were correlated positively with ages of CHB patients and significantly higher in males than in females.In patients with BMI>28 kg/m2 (obesity) and abnormal levels of ALT and TBIL,LS values were significantly increased as compared with those hav-ing normal levels of ALT and TBIL.The patients with ACLF had the highest LS value.Furthermore,LS values in the patients with LC were significantly higher than those in patients without LC.It is concluded that noninvasive measurement of liver fibrosis by FibroScan provides an alternative method to evaluate liver fibrosis of patients with CHB.In order to properly illustrate the stiffness value taken by transient elastography,patients' gender should be taken into consideration and it is also suggested to avoid possible influencing factors including liver inflammation (high levels of ALT and TBIL) and obesity (high BMI). | 丁红芳 吴婷 马科 王晓晶 武泽光 郭威 齐俊英 宁琴 | 2012 | Journal of Huazhong University of Science and Technology(Medical Sciences)2012，32，1： | 15 |
| 9 | Clinical application of liver stiffness measurement using transient elastography in chronic liver disease from longitudinal perspectives显示文摘Accurate determination of the presence and degree of fibrosis in liver is of great importance, because the prognosis and management strategies for chronic liver disease depend mainly on these factors. To date, liver biopsy (LB) remains the 'gold standard' for assessing the severity of liver fibrosis; however, LB is often limited by its invasiveness, sampling error, and intra/ inter-observer variability in histological interpretation. Furthermore, repeated LB examinations within a short time interval are indeed ineligible in a real clinical practice. Thus, due to the pressing need for non-invasive surrogates for liver fibrosis, transient elastography (TE),as a novel ultrasound based technology, has allowed a noninvasive measurement of liver stiffness and has gained in popularity over recent years. In the past few years, additional roles for transient TE beyond the initial purpose of a non-invasive surrogate for LB have included the prediction of the most two critical consequences of fibrosis progression: the development of portal hypertension-related complications and hepatocellular carcinoma. This indicates that the role of transient TE is not merely limited to reducing the need for LB, but transient TE can enable the establishment of tailored management strategies by providing more detailed prognostic information. In particular, under the concept in which the clinical course of liver fibrosis is dynamic and bidirectional, especially when appropriate intervention is commenced, transient TE can be used to track the dynamic changes in fibrotic burden during antiviral or antifibrotic treatment. This review discussed extended applications of transient TE in prediction of the development of real clinical endpoints from a longitudinal perspective. | Beom Kyung Kim James Fung Man-Fung Yuen Seung Up Kim | 2013 | World Journal of Gastroenterology2013，19，12： | 14 |
| 10 | Insulin resistance is associated with subclinical vascular disease in humans显示文摘Insulin resistance is associated with subclinical vascular disease that is not justified by conventional cardiovascular risk factors,such as smoking or hypercholesterolemia.Vascular injury associated to insulin resistance involves functional and structural damage to the arterial wall that includes impaired vasodilation in response to chemical mediators,reduced distensibility of the arterial wall(arterial stiffness),vascular calcification,and increased thickness of the arterial wall.Vascular dysfunction associated to insulin resistance is present in asymptomatic subjects and predisposes to cardiovascular diseases,such as heart failure,ischemic heart disease,stroke,and peripheral vascular disease.Structural and functional vascular disease associated to insulin resistance is highly predictive of cardiovascular morbidity and mortality.Its pathogenic mechanisms remain undefined.Prospective studies have demonstrated that animal protein consumption increases the risk of developing cardiovascular disease and predisposes to type 2 diabetes(T2D)whereas vegetable protein intake has the opposite effect.Vascular disease linked to insulin resistance begins to occur early in life.Children and adolescents with insulin resistance show an injured arterial system compared with youth free of insulin resistance,suggesting that insulin resistance plays a crucial role in the development of initial vascular damage.Prevention of the vascular dysfunction related to insulin resistance should begin early in life.Before the clinical onset of T2D,asymptomatic subjects endure a long period of time characterized by insulin resistance.Latent vascular dysfunction begins to develop during this phase,so that patients with T2D are at increased cardiovascular risk long before the diagnosis of the disease. | María M Adeva-Andany Eva Ameneiros-Rodríguez Carlos Fernández-Fernández Alberto Domínguez-Montero Raquel Funcasta-Calderón | 2019 | World Journal of Diabetes2019，10，2： | 14 |
| 11 | Performance of transient elastography in assessing liver fibrosis in patients with autoimmune hepatitis-primary biliary cholangitis overlap syndrome显示文摘AIM To investigate the performance of transient elastography(TE) for diagnosis of fibrosis in patients with autoimmune hepatitis-primary biliary cholangitis(AIHPBC) overlap syndrome.METHODS A total of 70 patients with biopsy-proven AIH-PBC overlap syndrome were included. Spearman correlation test was used to analyze the correlation of liver stiffness measurement(LSM) and fibrosis stage. Independent samples Student's t-test or one-way analysis of variance was used to compare quantitative variables. Receiver operating characteristics(ROC) curve was used to calculate the optimal cut-off values of LSM for predicting individual fibrosis stages. A comparison on the diagnostic accuracy for severe fibrosis was made between LSM and other serological scores.RESULTS Patients with AIH-PBC overlap syndrome had higher median LSM than healthy controls(11.3 ± 6.4 k Pa vs 4.3 ± 1.4 k Pa, P < 0.01). LSM was significantly correlated with fibrosis stage(r = 0.756, P < 0.01). LSM values increased gradually with an increased fibrosis stage. The areas under the ROC curves of LSM for stages F ≥ 2, F ≥ 3, and F4 were 0.837(95%CI: 0.729-0.914), 0.910(0.817-0.965), and 0.966(0.893-0.995), respectively. The optimal cut-off values of LSM for fibrosis stages F ≥ 2, F ≥ 3, and F4 were 6.55, 10.50, and 14.45 k Pa, respectively. LSM was significantly superior to fibrosis-4, glutaglumyl-transferase/platelet ratio, and aspartate aminotransferase-to-platelet ratio index scores in detecting severe fibrosis(F ≥ 3)(0.910 vs 0.715, P < 0.01; 0.910 vs 0.649, P < 0.01; 0.910 vs 0.616, P < 0.01, respectively).CONCLUSION TE can accurately detect hepatic fibrosis as a noninvasive method in patients with AIH-PBC overlap syndrome. | Hui-Min Wu Li Sheng Qi Wang Han Bao Qi Miao Xiao Xiao Can-Jie Guo Hai Li Xiong Ma De-Kai Qiu Jing Hua | 2018 | World Journal of Gastroenterology2018，24，6： | 13 |
| 12 | Synchronization of the four identical unbalanced rotors in a vibrating system of plane motion显示文摘A new mechanism is proposed to implement the synchronization of the four unbalanced rotors in a vibrating system, which consists of a main rigid frame (MRF) and two accessorial rigid frames (ARF). An analytical approach is developed to study the coupling dynamic characteristics of the four unbalanced rotors, which converts the problem of synchronization of the four unbalanced rotors into the existence and the stability of zero solutions for the non-dimensional differential equations of the angular velocity disturbance parameters (NDDEDP). The stability of zero solutions of the NDDEDP is decomposed into that of its generalized system and a system of the three first order differential equations for the disturbance parameters of the phase differences. The coupling dynamic characteristic of the four unbalanced rotors includes the inertia coupling, the stiffness coupling of angular velocity and the load torque coupling. The non-dimensional inertia coupling matrix is symmetric, the non dimensional matrix of the stiffness coupling of angular velocity is antisymmetric and its diagonal elements are all negative. Hence, the general system of the NDDEDP automatically satisfies the generalized Lyapunov equations when the non-dimensional inertia coupling matrix is positive definite and its elements are all positive. Using Routh-Hurwitz criterion the condition of stability of differential equations for the disturbance parameters of the phase differences is obtained. The load torque coupling makes the vibrating system have the dynamic characteristic of selecting motions and self-synchronization of the four unbalanced rotors arises from the dynamic characteristic of selecting motion of the vibrating system. When the two coefficients of coupling cosine effect of phase angles are all greater than 0 and the three indexes of synchronization are all far greater than 1, the vibrating system can implement an elliptical motion of the main rigid frame required in engineering. Numeric results show that the structural parameters of the proposed mechanism can guarantee the non-dimensional inertia matrix to be always positive definite. Computer simulation is carried out to verify the results of the theoretical investigation. | ZHAO ChunYu, WEN BangChun & ZHANG XueLiang School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110004, China | 2010 | Science China(Technological Sciences)2010，53，2： | 12 |
| 13 | Human immunodeficiency virus and hepatotropic viruses comorbidities as the inducers of liver injury progression显示文摘Hepatotropic viruses induced hepatitis progresses much faster and causes more liver-related health problems in people co-infected with human immunodeficiency virus(HIV). Although treatment with antiretroviral therapy has extended the life expectancy of people with HIV, liver disease induced by hepatitis B virus(HBV) and hepatitis C virus(HCV) causes significant numbers of non-acquired immune deficiency syndrome(AIDS)-related deaths in coinfected patients. In recent years, new insights into the mechanisms of accelerated fibrosis and liver disease progression in HIV/HCV and HIV/HBV co-infections have been reported. In this paper, we review recent studies examining the natural history and pathogenesis of liver disease in HIV-HCV/HBV co-infection in the era of direct acting antivirals(DAA) and antiretroviral therapy(ART). We also review the novel therapeutics for management of HIV/HCV and HIV/HBV coinfected individuals. | Murali Ganesan Larisa Y Poluektova Kusum K Kharbanda Natalia A Osna | 2019 | World Journal of Gastroenterology2019，25，4： | 12 |
| 14 | Environmental Adaptive Control of a Snake-like Robot With Variable Stiffness Actuators显示文摘This work investigates adaptive stiffness control and motion optimization of a snake-like robot with variable stiffness actuators. The robot can vary its stiffness by controlling magnetorheological fluid(MRF) around actuators. In order to improve the robot's physical stability in complex environments, this work proposes an adaptive stiffness control strategy. This strategy is also useful for the robot to avoid disturbing caused by emergency situations such as collisions. In addition, to obtain optimal stiffness and reduce energy consumption, both torques of actuators and stiffness of the MRF braker are considered and optimized by using an evolutionary optimization algorithm. Simulations and experiments are conducted to verify the proposed adaptive stiffness control and optimization methods for a variable stiffness snake-like robots. | Dong Zhang Hao Yuan Zhengcai Cao | 2020 | IEEE/CAA Journal of Automatica Sinica2020，7，3： | 11 |
| 15 | Dynamic characteristics of a novel damped outrigger system显示文摘This paper presents exact analytical solutions for a novel damped outrigger system, in which viscous dampers are vertically installed between perimeter columns and the core of a high-rise building. An improved analytical model is developed by modeling the effect of the damped outrigger as a general rotational spring acting on a Bernoulli-Euler beam. The equivalent rotational spring stiffness incorporating the combined effects of dampers and axial stiffness of perimeter columns is derived. The dynamic stiffness method(DSM) is applied to formulate the governing equation of the damped outrigger system. The accuracy and effi ciency are verifi ed in comparison with those obtained from compatibility equations and boundary equations. Parametric analysis of three non-dimensional factors is conducted to evaluate the infl uences of various factors, such as the stiffness ratio of the core to the beam, position of the damped outrigger, and the installed damping coeffi cient. Results show that the modal damping ratio is signifi cantly infl uenced by the stiffness ratio of the core to the column, and is more sensitive to damping than the position of the damped outrigger. The proposed analytical model in combination with DSM can be extended to the study of structures with more outriggers. | Tan Ping Fang Chuangjie Zhou Fulin | 2014 | Earthquake Engineering and Engineering Vibration2014，13，2： | 11 |
| 16 | One-dimensional dynamic compressive behavior of dry calcareous sand at high strain rates显示文摘Calcareous sand has distinct characteristics in comparison with silica sand, such as dynamic behavior at high strain rates(HSRs). This is closely related to pile driving, aircraft wheel loading and mining activities. To understand the response of calcareous sand at HSRs, a series of dynamic tests is performed using the split Hopkinson pressure bar(SHPB) with steel sleeve, including 6 validation tests of bar-against-bar and 16 comparative tests relevant to the relative density and strain rate of calcareous and silica sands.The apparent dynamic stiffness of calcareous sand is approximately 10% of that for silica sand due to different particle shapes and mineral compositions. The axial stress-strain response of silica sand is mainly governed by the deformation of individual grain and soil skeleton, and particle crushing. However, porous calcareous sand shows yielding and strain-hardening responses that are always followed by particle crushing. As the applied loading increases, the particle crushing of calcareous sand develops from local instability to whole breakage. Calcareous sand has lower viscous flow effects compared with silica sand at HSRs. | Yaru Lv Jiagui Liu Ziming Xiong | 2019 | Journal of Rock Mechanics and Geotechnical Engineering2019，11，1： | 10 |
| 17 | Study of detection times for liver stiffness evaluation by shear wave elastography显示文摘AIM:To investigate enough valid measurements(VMs)to assess liver fibrosis in chronic hepatitis B patients(CHB).METHODS:One hundred and twelve CHB patients(25women,87 men)with a mean age of 38.43 years received liver stiffness evaluations using real-time shear wave elastography for 10 VMs.All patients underwent liver biopsy.Based on the biopsy pathology,the liver stiffness data obtained from different VMs(1,2,3,5and 10 times)were compared for the evaluation of liver fibrosis.The correlation between the elastic modulus means of the liver obtained from different VMs of detection at each pathological stage was analysed.The receiver operating characteristic(ROC)curve was employed to determine the diagnostic performance of different VMs of detection,and the areas under the ROC curve of different groups were compared.RESULTS:The liver stiffness values obtained from 1 VM,2 VMs,3 VMs,5 VMs and all 10 VMs for stage F0 were 6.95±2.01 kPa,6.87±1.83 kPa,6.90±1.88 kPa,6.95±1.93kPa and 7.15±1.89 kPa,respectively(F=0.043,P=0.996).For stage F1,these values were 7.12±1.72 kPa,7.24±1.72 kPa,7.21±1.74 kPa,7.10±1.78 kPa and7.04±1.70 kPa,respectively(F=0.075,P=0.990).For stage F2,they were 9.37±3.87 kPa,9.18±3.68 kPa,9.19±3.81 kPa,9.18±3.81 kPa and 9.19±3.53 kPa,respectively(F=0.012,P=1.000).For stage F3,these were 11.91±3.88 kPa,11.78±4.04 kPa,11.83±4.07kPa,11.94±4.17 kPa and 12.00±4.02 kPa,respectively(F=0.010,P=1.000).For stage F4,the readings were 19.30±7.63 kPa,19.40±7.36 kPa,19.54±7.43kPa,19.73±7.21 kPa and 20.25±7.22 kPa,respectively(F=0.054,P=0.995).There were no significant differences between these groups.Intraclass correlation coefficients among different pathological stages(F0-F4)with different detection VMs were 0.995,0.993,0.996,0.994 and 0.996,respectively.The mean elasticity values from 1 VM,2 VMs,3 VMs,5 VMs and 10 VMs can accurately distinguish fibrosis stages(F0 vs F1234,F01 vs F234,F012 vs F34 and F0123 vs F4)with no significant differences in the five groups(P>0.05 for all).CONCLUSION:One VM may be sufficient to assess liver fibrosis by using SWE without any significant loss of accuracy in patients with CHB.However,future studies of larger patient samples are necessary for the validation of this method. | Ze-Ping Huang Xin-Ling Zhang Jie Zeng Jian Zheng Ping Wang Rong-Qin Zheng | 2014 | World Journal of Gastroenterology2014，20，28： | 10 |
| 18 | Noninvasive assessment of portal hypertension in cirrhosis:Liver stiffness and beyond显示文摘Liver stiffness measurement(LSM)is a good,but still limited tool to noninvasively assess complications and prognosis in patients with advanced liver disease.This review aims to consider the role of LSM for the diagnosis of portal hypertension-related complications and for assessment of prognosis in cirrhotic patients,and to highlight the drawbacks as well as some alternatives for improving the performance.Hence,this field is far from being closed,and deserves more attention.There is still a place for more carefully designed studies to find new,innovative and reliable approaches. | Horia Stefanescu Bogdan Procopet | 2014 | World Journal of Gastroenterology2014，20，45： | 9 |
| 19 | New Method to Improve Dynamic Stiffness of Electro-hydraulic Servo Systems显示文摘Most current researches working on improving stiffness focus on the application of control theories.But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated,so the control action is lagged.Thus dynamic performance against force disturbance and dynamic load stiffness can't be improved evidently by advanced control algorithms.In this paper,the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is analyzed.On this basis,the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put forward.And a scheme using double servo valves to realize flow feedforward compensation is presented,in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in time.The two valves are arranged in parallel to control the cylinder jointly.Furthermore,the model of flow compensation is derived,by which the product of the amplitude and width of the valve's pulse command signal can be calculated.And determination rules of the amplitude and width of pulse signal are concluded by analysis and simulations.Using the proposed scheme,simulations and experiments at different positions with different force changes are conducted.The simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling time.That is,system dynamic load stiffness is evidently raised.This paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems. | BAI Yanhong QUAN Long | 2013 | Chinese Journal of Mechanical Engineering2013，26，5： | 9 |
| 20 | High precision and efficiency robotic milling of complex parts:Challenges,approaches and trends显示文摘Due to the advantages of large workspace,low cost and the integrated vision/force sensing,robotic milling has become an important way for machining of complex parts.In recent years,many scholars have studied the problems existing in the applications of robotic milling,and lots of results have been made in the dynamics,pose planning,deformation control etc.,which provides theoretical guidance for high precision and high efficiency of robotic milling.From the perspective of complex parts robotic milling,this paper focuses on machining process planning and control techniques including the analysis of the robot-workspace,robot trajectory planning,vibration monitoring and control,deformation monitoring and compensation.As well as the principles of these technologies such as robot stiffness characteristics,dynamic characteristics,chatter mechanisms,and deformation mechanisms.The methods and characteristics related to the theory and technology of robotic milling of complex parts are summarized systematically.The latest research progress and achievements in the relevant fields are reviewed.It is hoped that the challenges,strategies and development related to robotic milling could be clarified through the carding work in this paper,so as to promote the application of related theories and technologies in high efficiency and precision intelligent milling with robot for complex parts. | Zerun ZHU Xiaowei TANG Chen CHEN Fangyu PENG Rong YAN Lin ZHOU Zepeng LI Jiawei WU | 2022 | Chinese Journal of Aeronautics2022，35，2： | 9 |
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