50 research outputs found

    THE LOCAL BIOMECHANICAL ANALYSIS OF LOWER LIMB ON COUNTER-MOVEMENT JUMP BETWEEN BAREFOOT AND SHOD PEOPLE WITH DIFFERENT FOOT MORPHOLOGY

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    The aim of this study was to explore the kinematic variations in knee and ankle joints and the ground reaction force between habitually barefoot (HBM) and shod males (HSM) during countermovement jump. Twenty-eight males (14 HBM,14 HSM) participated in this experiment. An 8-camera Vicon motion system was used to collect the kinematic data of knee and ankle joints from 3 dimensions and the force plate was used to collect the ground reaction force in take-off phase. Results in take-off phase showed that HSM produced two peak forces to take off and showed significantly greater knee ROM in sagittal plane, as well as greater ankle inversion and external rotation. In conclusion, the foot morphological differences can result in the different influence on jump performance. The relevant practioner should pay close attention to the effect of foot morphology on jump in training

    Automated Quantitative Analysis of Blood Flow in Extracranial–Intracranial Arterial Bypass Based on Indocyanine Green Angiography

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    Microvascular imaging based on indocyanine green is an important tool for surgeons who carry out extracranial–intracranial arterial bypass surgery. In terms of blood perfusion, indocyanine green images contain abundant information, which cannot be effectively interpreted by humans or currently available commercial software. In this paper, an automatic processing framework for perfusion assessments based on indocyanine green videos is proposed and consists of three stages, namely, vessel segmentation based on the UNet deep neural network, preoperative and postoperative image registrations based on scale-invariant transform features, and blood flow evaluation based on the Horn–Schunck optical flow method. This automatic processing flow can reveal the blood flow direction and intensity curve of any vessel, as well as the blood perfusion changes before and after an operation. Commercial software embedded in a microscope is used as a reference to evaluate the effectiveness of the algorithm in this study. A total of 120 patients from multiple centers were sampled for the study. For blood vessel segmentation, a Dice coefficient of 0.80 and a Jaccard coefficient of 0.73 were obtained. For image registration, the success rate was 81%. In preoperative and postoperative video processing, the coincidence rates between the automatic processing method and commercial software were 89 and 87%, respectively. The proposed framework not only achieves blood perfusion analysis similar to that of commercial software but also automatically detects and matches blood vessels before and after an operation, thus quantifying the flow direction and enabling surgeons to intuitively evaluate the perfusion changes caused by bypass surgery

    Sequence-Specific Detection of DNA Strands Using a Solid-State Nanopore Assisted by Microbeads

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    Simple, rapid, and low-cost detection of DNA with specific sequence is crucial for molecular diagnosis and therapy applications. In this research, the target DNA molecules are bonded to the streptavidin-coated microbeads, after hybridizing with biotinylated probes. A nanopore with a diameter significantly smaller than the microbeads is used to detect DNA molecules through the ionic pulse signals. Because the DNA molecules attached on the microbead should dissociate from the beads before completely passing through the pore, the signal duration time for the target DNA is two orders of magnitude longer than free DNA. Moreover, the high local concentration of target DNA molecules on the surface of microbeads leads to multiple DNA molecules translocating through the pore simultaneously, which generates pulse signals with amplitude much larger than single free DNA translocation events. Therefore, the DNA molecules with specific sequence can be easily identified by a nanopore sensor assisted by microbeads according to the ionic pulse signals

    Application of positive pulse to extract ions from HiPIMS ionization region

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    High power impulse magnetron sputtering (HiPIMS) is a promising physical vapor deposition technique with one of the main drawbacks being its relatively low deposition rate. In this article, a method was propose by using a positive ions extraction pulse (Uextract) which would be immediately applied to the sputtering target after the HiPIMS negative pulse to extract out the ions from the ionization region near the HiPIMS target. The Particle-InCell/Monte Carlo Collision (PIC-MCC) simulation, experiments, and theoretical study were conducted to investigate the ions extraction process. It is demonstrated that the higher potential moved from the target area to the substrate direction and the peak ion density was driven to the substrate direction, after applying the positive ions extraction pulse to the target. The measured ion-energy distribution function (IEDF) characteristics verified that the ions extraction method works. The experimental results indicated that the Ti + ion flux dramatically increased when the Uextract was over 50 V. Good agreement between the experimental and simulation results was obtained, validating the simulation conclusion. Finally, the microscopic mechanism of ions extraction is proposed

    Aescin Protects Neuron from Ischemia-Reperfusion Injury via Regulating the PRAS40/mTOR Signaling Pathway

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    Ischemic stroke is one of the major causes of disability; widely use of endovascular thrombectomy or intravenous thrombolysis leads to more attention on ischemia-reperfusion injury (I/R injury). Aescin, a natural compound isolated from the seed of the horse chestnut, has been demonstrated anti-inflammatory and antiedematous effects previously. This study was aimed at determining whether aescin could induce protective effects against ischemia-reperfusion injury and exploring the underlying mechanisms in vitro. Primary cultured neurons were subjected to 2 hours of oxygen-glucose deprivation (OGD) followed by 24 hours of simulated reperfusion. Aescin, which worked in a dose-dependent manner, could significantly attenuate neuronal death and reduce lactate dehydrogenase (LDH) release after OGD and simulated reperfusion. Aescin treatment at a concentration of 50 μg/ml provided protection with fewer side effects. Results showed that aescin upregulated the phosphorylation level of PRAS40 and proteins in the mTOR signaling pathway, including S6K and 4E-BP1. However, PRAS40 knockdown or rapamycin treatment was able to undermine and even abolish the protective effects of aescin; meanwhile, the levels of phosphorylation PRAS40 and proteins in the mTOR signaling pathway were obviously decreased. Hence, our study demonstrated that aescin provided neuronal protective effects against I/R injury through the PRAS40/mTOR signaling pathway in vitro. These results might contribute to the potential clinical application of aescin and provide a therapeutic target on subsequent cerebral I/R injury

    Bipolar high power impulse magnetron sputtering for energetic ion bombardment during TiN thin film growth without the use of a substrate bias

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    The effect of applying a positive voltage pulse (Urev = 10–150 V) directly after the negative high power impulse magnetron sputtering (HiPIMS) pulse (bipolar HiPIMS) is investigated for the reactive sputter deposition of TiN thin films. Energy-resolved mass spectroscopy analyses are performed to gain insight in the effect on the ion energy distribution function of the various ions. It is demonstrated that the energy of a large fraction of the ions can be tuned by a reverse target potential and gain energy corresponding to the applied Urev. Microscopy observations and x-ray reflectometry reveal densification of the films which results in an increase in the film hardness from 23.9 to 34 GPa as well as an increase in compressive film stress from 2.1 GPa to 4.7 GPa when comparing conventional HiPIMS with bipolar HiPIMS (Urev = 150 V)

    Histone Deacetylase Inhibitor Scriptaid Alleviated Neurological Dysfunction after Experimental Intracerebral Hemorrhage in Mice

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    Objectives. To investigate the role of Scriptaid in reducing brain injury after intracerebral hemorrhage (ICH) in mice. Methods. An ICH model was constructed by injecting autologous blood into the right basal ganglia in mice. The animals were administered 3.5 mg/kg of Scriptaid intraperitoneally after ICH. The hematoma volume and hemoglobin level were measured to examine hematoma resolution. A behavior test and brain edema and white matter injury examinations indicated brain injury after ICH. Results. Scriptaid treatment promoted hematoma resolution and reduced the hematoma volume 7 d after ICH compared with the vehicle group (P<0.05). Scriptaid treatment also alleviated the brain water content in the ipsilateral basal ganglia (P<0.05) and cortex (P<0.01) 3 d after ICH. In addition, Scriptaid improved neurological function recovery and alleviated white matter injury 35 d after ICH. Conclusions. Scriptaid can protect against brain injury after ICH and may be considered a new medical therapy method for ICH

    Impact of geriatric nutritional risk index on prognosis in peripheral artery disease patients undergoing endovascular therapy

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    Abstract The prevalence of peripheral artery disease continues to rise, with major amputations and mortality remaining prominent. Frailty is a significant risk factor for adverse outcomes in the management of the vascular disease. The geriatric nutritional risk index has been used to predict adverse outcomes in lower extremity peripheral artery disease and is a nutrition‐based surrogate for frailty. The authors recruited 126 patients with peripheral artery disease who underwent endovascular stent implantation. As in previous reports, malnutrition was diagnosed by the geriatric nutritional risk index. The authors used Kaplan‐Meier and multivariate Cox proportional hazards regression analyses to analyze the risk of major adverse limb events, which included mortality, major amputation, and target limb revascularization. There were 67 major adverse limb events during a median follow‐up of 480 days. Malnutrition on the basis of the geriatric nutritional risk index was present in 31% of patients. Cox regression analysis showed that malnutrition based on the geriatric nutritional risk index was an independent predictor of major adverse limb events. Kaplan‐Meier analysis showed that major adverse limb events increased with worsening malnutrition. Our single‐center, retrospective evaluation of geriatric nutritional risk index (as a synonym for body health) correlates with an increased risk of major adverse limb events. Future directions should focus not only on identifying these patients but also on modifying risk factors to optimize long‐term outcomes

    The Effect of Muscles Fatigue on the Knee’s Kinetics and Kinematics Characteristics

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    Badminton is very popular on college campuses. In badminton, the anterior cruciate ligament of the players has a higher risk of injury. There are many studies investigating the impact of fatigue on the injury of professional athletes, but few studies focused on college students. We hypothesized that the knee joint would experience greater ground reaction forces, valgus moments, and flexion moments of lunge contact in amateur after fatigue than those indicators before fatigue. Ten male badminton amateurs were enrolled in this study. They performed a lunge to hit the shuttlecock at the designated position and then quickly returned to the starting position before and after fatigue. Fatigue was induced by repeated isokinetic flexion/extension of the knee. Lower body kinematics and ground reaction force (GRF) were collected and further used to calculate the lower body joint moments from initial contact to maximum knee flexion. Compared to the pre-fatigue condition, the peak flexion moment (p = 0.012) and peak abduction moment of knee joint (p = 0.01), and maximum horizontal ground reaction force (p = 0.027) increased significantly at the initial contact (p = 0.01). After muscle fatigue, the knee buckling moment and valgus moment increased significantly at initial contact, and the horizontal backward maximum GRF also increased significantly. These changes might increase the injury risk of anterior cruciate ligament (ACL). The fatigue of the muscles around the knee joint did not change the maximum GRF in the vertical direction at the moment of contact. Combined with the results of our study, badminton coaches and teachers should increase the training of lower extremity muscle strength and endurance in our daily class and training, and also should pay special attention to the coordinated development of muscles
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