液压系统压力脉动的机理

主要对液压系统中压力产生脉动的机理进行分析 ,从而找出流体压力脉动的各种原因 ,总结出脉动压力的基本种类与特征 ,典型故障时的压力脉动波形 ,并对压力脉动的频率成分进行了分析 .

Primary Mechanisms for Novel Compound Pivanampeta Against Atherosclerosis in Rat and Rabbit Model of Atherosclerosis

Aim To investigate the anti-atherosclerotic mechanisms of the novel compoundpivanampeta in the early and later stages of atherosclerosis evolution. Methods Rats or rabbits wererandomly assigned to the control, the model and the pivanampeta-treated groups. The rats or rabbitsin the model group and the pivanampeta-treated group were fed with hypercholesterol diet. Thecarotids of rabbits were cut into pieces and stained with HE. The rat or rabbit serum levels of TC,LDL-CHO, HDL-CHO, IL-8, ET-1, PGI_2, TXA_2, and NO were assayed. The expressions of MCP-1 and IL-8mRNA on rabbit carotid were determined by semi-quantitative RT-PCR. Results Pivanampeta exerted aninhibitory effect on TXA_2 formation without PGI_2 production in the early and later stages ofatherosclerosis. The significantly increased release of NO and the decreased release of IL-8 in theanimals in pivanampeta-treated group were both detected in the rat atherosclerosis model. In therabbit atherosclerosis model the expressions of IL-8 and MCP-1 mRNA in pivanampeta-treated groupwere decreased significantly. However, the treatment with pivanampeta had no effect on the levels ofplasma cholesterol, MDA and SOD. Conclusion The increase of serum NO contents and the decrease ofplasma TXA_2 level, as well as its inhibition of expression of IL-8 and MCP-1 are probably involvedin the mechanisms underlying the anti-atherosclerotic effects of pivanampeta.

Anomalous origin of left pulmonary artery branch from the aorta with Fallot's tetralogy:one case report

We report the case of a ten-year-old boy who had often presented with respiratory distress since born. Chest X-ray showed an enlarged right ventricle. Echocardiography demonstrated characteristic features of Fallot＇s tetralogy and the left pulmonary artery could not be visualized. However, cardiac catheterization disclosed that the left pulmonary artery had an anomalous origin in the ascending aorta. The patient underwent total surgical correction of the defects. Nine days later, he was discharged. We present the results of a literature review of the incidence, physiopathological, clinical, diagnostic, and surgical characteristics of this rare disease.

Apopotic gene Bax expression in carotid plaque

The expression of BAX in carotid atherosclerosis and its regulation is far from defined. Objectives To investigate BAX expression in stable/fibrous and instable/vulnerable carotid plaque and its clinical significance. Methods 25 cases of carotid plaque specimens obtained from endarterectomy were divided into two groups, stable/fibrous 14 cases, vulnerable/instable 11 cases; aortic artery and its branches from hepatic transplantation donors 6 case as control The expression of proapoptotic BAX was detected by immunohistochemistry （IHC）, in situ hybridization （ISH） and in situ TdT dUTP nick end labeling （TUNEL）. Results 5 cases of BAX （ ＋ ） were detected by ICH and ISH, 4 case of TUNEL （ ＋ ） were detected by TUNEL in stable/fibrous carotid plaque , while 10 cases were BAX （ ＋ ）by IHC（P 〈 0.05 ） , 11 case by ISH and 9 case by TUNEL were detected in instable/vulnerable carotid plaque （P 〈0.01 ）, respectively. The intensity of BAX （ ＋ ） cells by IHC and ISH was 8.63±2.62 and 10.32 ± 3.12 in fibrous plaques,whereas 122 ±21.64 and 152 ± 23.35 in vulnerable plaques, respectively. No expression of BAX was found in controlled group. Conclusion The higher expression of Bax in vulnerable carotid plaque may be one mechanisms in molecular pathogenesis of carotid atherosclerosis which affect plaque stability and be the cause of higher incidence of stroke than fibrous carotid plaques, the regulation of BAX expression in different stage of atherosclerosis may provide targets in gene therapy for carotid atherosclerosis.

Successful management of hepatic artery pseudoaneurysm complicating chronic pancreatitis by stenting

A 41-year old alchoholic male with a history of chronic pancreatitis was admitted for nausea, vomiting and weight loss. Angiogram was performed and demonstrated an aneurysmal sac with a narrow neck originating from the inferior aspect of the distal portion of the proper hepatic artery. The origin of the pseudoaneurysm was covered with a 5 mm × 2.5 cm Viabahn cover stent （Gore）. A repeat angiogram showed some leak and a second stent （6 mm × 2.3 cm） was deployed and overlapped with the first stent by 3 mm. Contrast was injected and a repeat angiogram demonstrated complete exclusion of the aneurysm. A repeat computerized axial tomography （CAT） scan of the abdomen after 24 h showed successful stenting. The patient had an uneventful post-operative course.

Single low shear stress results in atherosclerosis in vivo

Objective: Whether single low shear stress can result in atherosclerosis without hyperliposis-diet in vivo or not is unknown. Methods: Based on an electromagnetic blood flow meter and a method to determine the pulsatile shear stress from blood flow rate waveform and its software,we developed an in vivo pulsatile blood flow rate-shear stress determining system.The left external carotid arteries of 20 adult New Zealand white rabbits were ligated and the rabbits were fed with a standard chow for 2,4,8 or 12 weeks,then the common carotid arteries of 2 sides in each rabbit were harvested for morphologic test. Results: The ligation reduced pulsatile shear stress of left common carotid significantly,for example,τ_ mean changed from(21.16±7.17) dynes/cm 2 to(3.13±2.28) dynes/cm 2(p=2.176E-21),meanwhile,the pulsatile shear stress of right common carotid did not change significantly,which lasted more than 12 weeks.Atherosclerotic plaques were found after 8 and 12 weeks in pulsatile-low-shear-stress left(not normal-shear-stress right) common carotid arteries.Conclusion:Single pulsatile low shear stress can result in atherosclerosis.It supports the pulsatile low shear stress(not hypolipidemia) is the key risk factor for atherosclerosis.

Elevated plasma level of matrix metalloproteinases-9 and its significance in patients with abdominal aortic aneurysms

Objective: To investigate the changes of the plasma level of MMP-9 (Matrix Metalloproteinase-9, MMP-9) in the patients with abdominal aortic aneurysms (AAAs) before and after the treatment, and evaluate the significance of MMP-9 in the pathogenesis of AAAs. Methods: Blood samples of 35 patients with AAAs and 10 patients with the arterial occlusive diseases (AODs) , which enrolled into the Vascular Surgery Center of Colonge University Hospital from February to August of 2002, were collected before and one month after surgical repair or less-invasive endovascular exclusion. The plasma concentrations of MMP-9 of all the collected samples were measured by means of enzyme-linked immunosorbent assay(ELISA), and compared between the two groups patients at different time point. Results: The mean plasma concentration of MMP-9 of AAAs was significantly higher than that of AODs prior to treatment [(90.3±9.1) ng/ml vs (23.6±7.3) ng/ml, P<0.05], and no apparent difference was showed in the patients with AODs [(23.6±7.3) ng/ml vs (25.3±5.8) ng/ml, P>0.05)] before and after the surgical bypass operation. However, in the patients with AAAs the plasma concentration of MMP-9 was apparently decreased one month after the surgical repair or endovascular exclusion compared with before [(28.6±8.4) ng/ml vs (90.3±9.1) ng/ml, P<0.05)]. No meaningful difference of the mean plasma MMP-9 concentration was seen between two groups after the both being successfully treated [(28.6±8.4) ng/ml vs (25.3±5.8) ng/ml, P>0.05]. Conclusion: Apparent elevation of plasma concentration of MMP-9 in the AAAs and its dramatic decrease after being treated implicated that MMP-9 might play an important role in the formation and development of AAAs. Meanwhile, to investigate the changes of MMP-9 level of AAAs could provide an practical way to facilitate the earlier diagnosis and long term surveillance for AAAs. More importantly, pharmacologic prevention and treatment of AAAs, in which the MMP-9 serves as effective target, might be possible in the future.

Network pharmacology based method for mechanistic investigation of the Compound Xintahua in the treatment of atherosclerosis

Objective:To explore the pharmacological basis of the Compound Xintahua (XTH) action in Atherosclerosis (AS) therapy, a network interaction analysis was conducted at the molecular level. Methods:TCMSP database and literature mining were used to analyze the main effective components in XTH, and the targets were predicted by Swiss Target Prediction server according to AS mechanism. The potential targets were introduced into the FunRich database for target annotation and analysis, the path analysis was finally performed based on the FunRich databases. To determine the mechanism of action of XTH. Results:A total of 316 compounds, 117 targets, and 290 signaling pathways were identified. And 16 effective compounds, 39 common targets, and 43 pathways were associated with AS. Conclusions:The results showed that the flavonoids, phenols, organic acids and terpenoids of XTH could participate in the process of lipid metabolism, angiogenesis, oxidation, inflammation, endocrine metabolism, cell proliferation and apoptosis, It was further found that they could play the role of anti-Atherosclerosis through multi-component, multi-target, and multi-channel synergistically.

The right hepatic artery syndrome

Various benign and malignant conditions could cause biliary obstruction. Compression of extrahepatic bile duct (EBD) by right hepatic artery was reported as a right hepatic artery syndrome but all cases were compressed EBD from stomach side. Our case compressed from dorsum was not yet reported, so it was thought to be a very rare case. We present here the first case of bile duct obstruction due to the compression of EBD from dorsum by right hepatic artery.

Autopsy study of anatomical features of the posterior gastric artery for surgical contribution

AIM： To investigate features of the posterior gastric arten/（PGA） with respect to incidence, location and size by using autopsy subjects. METHODS： Autopsies were performed on 72 cadavers of adults with no history of abdominal operations. The localization of the PGA, the distance between the root of the splenic artery and the origin of the PGA, and the external diameter of the PGA were examined. RESULTS： The PGA was recognized in all patients. In 70 （97.2%） cadavers, the PGA branched from the splenic artery, and one female in this group had two PGAs. In 1 （1.4%） patient, the PGA originated from the root of the celiac trunk and in another （1.4%） patient, the PGA branched from the superior polar artery. Overall, the PGA extended for a length of 5.8-12.2 （mean, 8.4） cm from the root of the splenic artery, and the external diameter of the PGA was 1.2-3.2 （mean, 2） mm. CONCLUSION： The anatomical features of the PGA can be readily observed and characterized by autopsy. This study has provided valuable information on the features of the PGA useful in the planning of surgical treatment.

Size and spatial distribution of landslides induced by the2015 Gorkha earthquake in the Bhote Koshi river watershed

The Mw 7.8 Gorkha earthquake in Nepal on April 25, 2015, produced thousands of landslides in the Himalayan mountain range. After the earthquake, two field investigations along Araniko Highway were conducted. Then, using remote sensing technology and geographic information system(GIS)technology, 1481 landslides were identified along the Bhote Koshi river. Correlations between the spatial distribution of landslides with slope gradient and lithology were analyzed. The power-law relationship of the size distribution of earthquake-induced landslides was examined in both the Higher Himalaya and Lesser Himalaya. Possible reasons for the variability of the power exponent were explored by examining differences in the geological situations of these areas. Multi-threshold cellular automata were introduced to model the complexity of system components. Most of the landslides occurred at slope gradients of 30°–40°, and the landslide density was positively correlated with slope gradient. Landslides in hard rock areas were more common than in soft rock areas. The cumulative number-area distribution of landslides induced by the Gorkha earthquake exhibited a negative power-law relationship, but the power exponents were different: 1.13 in the Higher Himalaya, 1.36 and Lesser Himalaya. Furthermore,the geological conditions were more complex and varied in the Lesser Himalaya than in the Higher Himalaya, and the cellular automata simulation results indicated that, as the complexity of system components increased, the power exponent increased.Therefore, the variability of the power exponent of landslide size distribution should ascribe to the complexity of geological situations in the Bhote Koshi river watershed.

Success in Treating Hepatoblastoma by Transcatheter Arterial Infusion Combined with Radical Resection:a Case Report

Hepatoblastoma is the most common malignant hepatic tumor in children. About 50% of the cases occur before the age of 18 months and almost all before the age of 2 years. We present an extremely rare case of hepatoblastoma in an 11-year-old girl, which was pathologically verified and treated twice with transcatheter arterial infusion combined with radical resection. To date she has been followed-up for 15 years and has shown normal development after the operation. She has received no chemotherapy or radiation and has displayed no evidence of metastatic or recurrent disease.

Osteoporosis as A Source of Tissue Mineralization Research on Osteoporosis Therapy and Dissolution of Arterial Mineralization

Based on research conducted by the author in the last thirty-five years, this article presents the physicochemical mechanisms of the osteoporosis process, transport of substances created as its result, and the phenomena of tissue mineralization resulting from osteoporosis. Examination of bones, joint cartilage, arteries, veins, parts of heart, thyroid, salivary glands, various tumors and others was conducted with the use of biological and polarizing microscopy, SEM, EDS, ASA, IR, Raman spectroscopy, and X-ray diffraction. Several devices of the same kind, e.g. different types of SEM, were used. Specimens used for examination were obtained from post-surgery and post rnortem materials. Examination of human bones focused on their mineralization and demineralization （osteoporosis）. Examination of the mineralization of other tissues was conducted in terms of the ageing of human body. Obtained results show that the process of osteoporosis leads not just to mechanical degradation of bones, but through the transport of ions （mainly Ca and P）, it also causes mineralization of soft tissue. Such mineralization occurs in mineralization centers that have been classified in regard to genetics. Tissue mineralization in its first stage is latent and consists of including atoms, mainly Ca and P, into the biological structures of compounds that build the tissues. Latent mineralization may evolve into the next stage--apparent mineralization. Both types of mineralization cause many health issues and may lead to death. This article also presents initial results of research on dissolution of aortic mineralization.

Construction Method of 3D Aorta Model

With the help of engineering technologies, there are varieties of medical supports such as surgical simulations, preoperative plans, intraoperative supports, and diagnostic explanations. In order to perform preoperative plans, the simulation model of the target organ is necessary, and is usually generated from some fine images obtained by imaging devices such as CT （computed tomography） or MRI （magnetic resonance imaging）. These devices, however, are very large and it is difficult to use them during the surgery although there is a kind of MRI that can be used during operations. On the other hand, there is a device called Ultrasonography （US Echo）. It is so handy and can be easily used during operations without radiation or magnetic effect. US images, however, are not usually used for the construction of 3D model for preoperative plans since there are so many noises in the image, and the quality of the image is not so good compared to the images obtained by CT or MRI. Therefore, the authors have tried to construct 3D volumetric shape model from just two 2D US （ultrasound） images, which are the horizontal and vertical cross-section images of the target organ. Their concrete target organ and surgery are the aorta and AAE （annuloaortic ectasia）, respectively. With some technologies of image processing, the boundary of the aorta is extracted for both cross-section images, and the thickness of the aorta is estimated. These processes are applied to not only the aorta wall but also the aorta valve. Finally, the aorta shape model can be constructed by inserting the estimated horizontal aorta images into the estimated vertical one. The constructed model has three dimensions so that it can be viewed from any point of view.

Sensorless Control of Switched Reluctance Motor Drive Systems

This paper presents a sliding mode observer for sensorless operation of SRM （switched reluctance motor） drive. Design of such an observer depends mainly on the nonlinear model of SRM. In this technique, neither extra hardware nor huge memory space are not required but it only requires active phase measurements. Furthermore, PI （proportional integral） and adaptive FLPI （fuzzy logic PI） controllers are suggested to operate individually along with the SMO （sliding mode observer） to cover a full speed range of sensorless controller. Both controller schemes operate in PWM （pulse width modulation） control mode. The proposed observer is implemented and tested using a digital signal processor. All results obtained with both simulation and experimental investigations corroborate the superior performance of the adaptive fuzzy logic controller （FLPI） when compared with those of PI controller.

Internal flow structure,fault detection,and performance optimization of centrifugal pumps

This review mainly summarizes the latest developments in the internal flow field and external characteristics of centrifugal pumps.In particular,the latest findings of centrifugal pumps focused on turbulence and cavitation models,flow visualization methods,and fault detection based on noise and vibration.The external characteristics,cavitation,and vibration of the centrifugal pump were extensively discussed.In addition,advanced multi-objective optimization methods for improving impeller’s efficiency and reducing net positive suction head(NPSH)were briefed.Although some progress was made in this field,there remain many unsolved problems,such as monitoring and modeling of cavitation,rotational stall phenomenon,and discrepancies between simulation and measurement.In the future,researchers are encouraged to employ multi-dimensional flow visualization technologies and high-performance computing facilities to advance existing understandings on these issues and create new research directions.

On Existence and Uniqueness of Random Impulsive Differential Equations

This paper studies existence and uniqueness for random impulsive differential equations.The authors first generalize a random fixed point theorem of Schaefer's type.Then the authors shall rely on the generalized Schaefer's type random fixed point theorem to discuss the existence of the system.In addition,the authors study the existence and uniqueness of random impulsive differential equations by applying random Banach fixed point theorem and obtain some less conservative results.Finally,an example is given to illustrate the effectiveness of the results.

Individual aortic baroreceptors are sensitive to different ranges of blood pressures

Many receptors,including thermal receptors and mechanical receptors,are only activated by stimuli within a clearly defined range of intensities.Differences in the receptive ranges enable individual receptors and their sensory centers to precisely detect the intensity of the stimulus and changes in intensity.Baroreceptors are the sensory terminals of the baroreflex.It is well understood that an increasing number of baroreceptors are recruited to produce afferent action potentials as the blood pressure increases,indicating that individual baroreceptors have different pressure thresholds.The present study revealed that individual baroreceptors could stop their afferent signals when the blood pressure exceeds a certain level,indicating that individual baroreceptors are sensitive to a specific range of blood pressure.The receptive ranges of individual baroreceptors differ in terms of the total range,the lower threshold,and the upper threshold.Of 85 baroreceptors examined in this study,the upper thresholds for about half were within the physiological blood pressure range.These results indicate that supraphysiological blood pressure is unlikely to be encoded by the recruitment of more baroreceptors.Instead,supraphysiological blood pressure levels might be signaled by an increase in the frequency of action potentials or by other mechanisms.In conclusion,our results indicate that rabbit baroreceptors are activated by blood pressure levels within specific receptive ranges.These findings should encourage further studies to examine the role of population coding of blood pressure by baroreceptors in the baroreflex.