Role of endothelial glycocalyx in sliding friction at the catheter-blood vessel interface

Catheterization is a common medical operation to diagnose and treat cardiovascular diseases. The blood vessel lumen is coated with endothelial glycocalyx layer (EGL), which is important for the permeability and diffusion through the blood vessels wall, blood hemodynamics and mechanotransduction. However EGL's role in catheter-blood vessel friction is not explored. We use a porcine aorta to mimic the blood vessel and a catheter loop was made to rub in reciprocating sliding mode against it to understand the role of catheter loop curvature, stiffness, normal load, sliding speed and EGL on the friction properties. Trypsin treatment was used to cause a degradation of the EGL. Decrease in catheter loop stiffness and EGL degradation were the strongest factors which dramatically increased the coefficient of friction (COF) and frictional energy dissipation at the aorta-catheter interface. Increasing sliding speed caused an increase but increase in normal load first caused a decrease and then an increase in the COF and frictional energy. These results provide the basic data for safety of operation and damage control during catheterization in patients with degraded EGL

Atherosclerosis T1-weighted characterization (CATCH): evaluation of the accuracy for identifying intraplaque hemorrhage with histological validation in carotid and coronary artery specimens

Background: Coronary high intensity plaques (CHIPs) detected using cardiovascular magnetic resonance (CMR) coronary atherosclerosis T1-weighted characterization with integrated anatomical reference (CATCH) have been shown to be positively associated with high-risk morphology observed on intracoronary optical coherence tomography (OCT). This study sought to validate whether CHIPs detected on CATCH indicate the presence of intraplaque hemorrhage (IPH) through ex vivo imaging of carotid and coronary plaque specimens, with histopathology as the standard reference. Methods: Ten patients scheduled to undergo carotid endarterectomy underwent CMR with the conventional T1-weighted (T1w) sequence. Eleven carotid atherosclerotic plaques removed at carotid endarterectomy and six coronary artery endarterectomy specimens removed from patients undergoing coronary artery bypass grafting (CABG) were scanned ex vivo using both the conventional T1w sequence and CATCH. Both in vivo and ex vivo images were examined for the presence of IPH. The sensitivity, specificity, and Cohen Kappa (k) value of each scan were calculated using matched histological sections as the reference. k value between each scan in the discrimination of IPH was also computed. Results: A total of 236 in vivo locations, 328 ex vivo and matching histology locations were included for the analysis. Sensitivity, specificity, and k value were 76.7%, 95.3%, and 0.75 for in vivo T1w imaging, 77.2%, 97.4%, and 0.78 for ex vivo T1w imaging, and 95.0%, 92.1%, and 0.84 for ex vivo CATCH, respectively. Moderate agreement was reached between in vivo T1w imaging, ex vivo T1w imaging, and ex vivo CATCH for the detection of IPH: between in vivo T1w imaging and ex vivo CATCH (k = 0.68), between ex vivo T1w imaging and ex vivo CATCH (k = 0.74), between in vivo T1w imaging and ex vivo T1w imaging (k = 0.83). None of the coronary artery plaque locations showed IPH. Conclusion: This study demonstrated that carotid CHIPs detected by CATCH can be used to assess for IPH, a high-risk plaque feature

An Energy Storage System Sizing Method for Wind Power Integration

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Left Ventricular Aneurysm Repair: Off-pump Linear Plication versus On-pump Patch Plasty

Abstract Objective: The study aimed to compare the clinical outcomes of simplified linear plication and classic patch plasty in patients with left ventricular aneurysm (LVA). Methods: We retrospectively reviewed 282 patients undergoing LVA repair between 2006 and 2016. After propensity score matching, 45 pairs of patients receiving LVA surgery were divided into either a patch group (on-pump endoventricular patch plasty) or a plication group (off-pump linear plication). Then, their early surgical outcomes and long-term survival were compared in two matched groups. Results: The heart function improvement at discharge was similar in the two matched groups, while patients in the patch group more commonly suffered from low cardiac output syndrome (P=0.042) with higher proportion of intra-aortic balloon pumping assistance (P=0.034) than patients in the plication group. Compared with patients in the patch group, the patients in the plication group had shorter recovery times, regarding to mechanical ventilation, intensive care unit stay, and hospital stay (P<0.001, P<0.001, and P=0.001, respectively). No significant difference was found in the long-term survival (P=0.62). Conclusions: Off-pump linear plication presented acceptable results in terms of early outcomes and long-term survival. For high-risk patients, the simplified LVA repair technique may be an option

Patient-specific finite element analysis of frictional behavior in different esophageal regions during endoscopy

Endoscopy is a common and effective method to treat digestive system diseases. Not only can it detect the physiological state of the digestive tract, but also can conduct clinical operations. As a result, it’s of great significance to make clear the relationship between the clinical operation and the complications. Methods: Considering the difficulty in measuring the contact force and determining the stress distribution in real time during endoscopy, a specific-patient finite element model for the frictional behavior at the endoscope-esophagus interface was built in current study. By collecting the CT data of the patient, a 3D esophagus model was built and divided into three characteristic regions (narrow region, thoracic region and abdominal region) according to the physiological structure. Results: Results showed that the radius of the narrowest position was the dominant factor for the maximum von Mises stress when the endoscope passed through the narrow region. For abdominal region and thoracic region, with the increasing coefficient of friction (COF) and amplitude, the total force duo to frictional force (CFSM), frictional dissipation (FD), strain energy (SE) and maximum von Mises stress (Max) all increased correspondingly. Meanwhile, the region of stress concentration gradually approached the initial contact stage. Conclusions: The results can provide theoretical basis and technical support for clinical application and offer some suggestions for medical workers during endoscopy as well

Short and long-term outcomes after off-pump coronary endarterectomy stratified by different target vessels

Abstract Background The efficacy of off-pump coronary endarterectomy (CE) has been proven in patients with diffuse coronary artery disease (DCAD). However, the clinical benefits of of-pump CE stratified by different target vessels remain controversial. This retrospective study assessed the effect of the territory and number of CE on short- and long-term outcomes of DCAD. Methods From January 2012 to December 2014, 246 patients undergoing off-pump coronary artery bypass grafting (OPCABG) + CE were included. The patients were grouped by the territory and number of CE. The primary endpoints were postoperative acute myocardial infarction (PMI) and long-term major adverse cardiovascular and cerebrovascular events (MACCE). Results Sixty-five patients (26.42%) were in the left anterior descending branch (LAD) group (CE on LAD), 134(54.47%) in the right coronary artery (RCA) group (CE on RCA), and 47(19.10%) in the multi-vessels group. PMI in the LAD group, RCA group, and multi-vessels group were 3.08%, 6.72%, and 14.89%, respectively (P = 0.08). Multi-vessels CE (OR = 9.042, 95%CI 2.198–37.193, P = 0.002), CE-plaque length ≥ 3 cm (OR = 6.247, 95%CI 2.162–18.052, P < 0.001), and type 2 diabetes mellitus (2DM) (OR = 4.072, 95%CI 1.598–10.374, P = 0.003) were independent risk factors of PMI. The long-term (mean 76 months) MACCE in the LAD group, RCA group, and multi-vessels group were 13.85%, 17.91%, and 10.64%, respectively (P = 0.552). Cox analysis indicated that PMI (HR = 7.113, 95%CI 3.129–16.171, P < 0.001) and Age ≥ 65 years (HR = 2.488, 95%CI 1.214–5.099, P = 0.013) increased the risk of long-term MACCE. Conclusions Multi-vessel CE and CE-plaque length ≥ 3 cm significantly increased risk of PMI after OPCABG + CE, but the territory and number of CE did not affect long-term MACCE

A coumarin analogue NFA from endophytic Aspergillus fumigatus improves drought resistance in rice as an antioxidant

Abstract Background Drought and its resulting oxidative damage are the major yield limiting factors for crops in arid and semi-arid regions. Recent studies have found that endophytic fungi coexisting in plants can alleviate biotic or abiotic damage to plant growth and development. In order to screen for the endophytes associated with drought stress, 12 strains of endophytic fungi with high antioxidant activity isolated from riparian plants Myricaria laxiflora were evaluated for their effects in rice by the crude extracts. Results Of the 12 endophytic fungi, Aspergillus fumigatus SG-17 functioned most effectively, with the crude extract exhibiting relatively higher antioxidant capacity both in vivo and in vitro. The subsequent MS and NMR analysis showed that the primary substance responsible for the antioxidant activity in the extract was (Z)-N-(4-hydroxystyryl) formamide (NFA), an analogue of coumarin. Enzyme activity assay in nerve cells SH-SY5Y showed that NFA could maintain the membrane integrity and regulate the antioxidase activity under oxidative stress. In rice suffering drought stress, NFA effectively alleviated the harm by regulating the contents of NADPH oxidases, antioxidants and heat shock proteins, all of which are closely related with the reactive oxygen species pathway. Conclusion These findings indicated that some endophytes from plants often subjected to flooding and oxidative stress could enhance drought resistance by producing compounds such as NFA to regulate the oxidative pathway