586 research outputs found
Flexible supporting and fixing method for hybrid ultrasonic motor using longitudinal and torsional vibration modes
A new flexible supporting and fixing method for hybrid ultrasonic motor using longitudinal and torsional vibration modes is presented. A motor base is used to support and fix the motor, which has dual concentric bearings in opposite shell sides and a fixing slot. The axis of the motor has two extended parts outside the both sides of the motor. Once the motor has been assembled completely, the two extended parts of the motor axis will be inserted into the concentric bearings, which support the motor and restrict several degrees of freedom (DOFs) of the motor, such as the translational DOFs along X and Y axes, the rotational DOFs around X and Y axes. The motor has a flexible fixing sheet which placed near the piezoelectric ceramics, and the flexibility of the fixing is discussed by analyzing the thickness and the foot length of fixing sheet. The fixing sheet is fixed on the fixing slot with glue, which restricts the translational DOF along Z axis and rotational DOF around Z axis of the stator. The experiment results show that there is little influence on the motor working performance by using this supporting and fixing method; the motor can work smoothly and steadily and the maximum speed of the motor can exceed 2000 r/min
Study of the cytological features of bone marrow mesenchymal stem cells from patients with neuromyelitis optica.
Neuromyelitis optica (NMO) is a refractory autoimmune inflammatory disease of the central nervous system without an effective cure. Autologous bone marrow‑derived mesenchymal stem cells (BM‑MSCs) are considered to be promising therapeutic agents for this disease due to their potential regenerative, immune regulatory and neurotrophic effects. However, little is known about the cytological features of BM‑MSCs from patients with NMO, which may influence any therapeutic effects. The present study aimed to compare the proliferation, differentiation and senescence of BM‑MSCs from patients with NMO with that of age‑ and sex‑matched healthy subjects. It was revealed that there were no significant differences in terms of cell morphology or differentiation capacities in the BM‑MSCs from the patients with NMO. However, in comparison with healthy controls, BM‑MSCs derived from the Patients with NMO exhibited a decreased proliferation rate, in addition to a decreased expression of several cell cycle‑promoting and proliferation‑associated genes. Furthermore, the cell death rate increased in BM‑MSCs from patients under normal culture conditions and an assessment of the gene expression profile further confirmed that the BM‑MSCs from patients with NMO were more vulnerable to senescence. Platelet‑derived growth factor (PDGF), as a major mitotic stimulatory factor for MSCs and a potent therapeutic cytokine in demyelinating disease, was able to overcome the decreased proliferation rate and increased senescence defects in BM‑MSCs from the patients with NMO. Taken together, the results from the present study have enabled the proposition of the possibility of combining the application of autologous BM‑MSCs and PDGF for refractory and severe patients with NMO in order to elicit improved therapeutic effects, or, at the least, to include PDGF as a necessary and standard growth factor in the current in vitro formula for the culture of NMO patient‑derived BM‑MSCs
Towards offering more useful data reliably to mobile cloudfrom wireless sensor network
The integration of ubiquitous wireless sensor network (WSN) and powerful mobile cloud computing (MCC) is a research topic that is attracting growing interest in both academia and industry. In this new paradigm, WSN provides data to the cloud, and mobile users request data from the cloud. To support applications involving WSN-MCC integration, which need to reliably offer data that are more useful to the mobile users from WSN to cloud, this paper first identifies the critical issues that affect the usefulness of sensory data and the reliability of WSN, then proposes a novel WSN-MCC integration scheme named TPSS, which consists of two main parts: 1) TPSDT (Time and Priority based Selective Data Transmission) for WSN gateway to selectively transmit sensory data that are more useful to the cloud, considering the time and priority features of the data requested by the mobile user; 2) PSS (Priority-based Sleep Scheduling) algorithm for WSN to save energy consumption so that it can gather and transmit data in a more reliable way. Analytical and experimental results demonstrate the effectiveness of TPSS in improving usefulness of sensory data and reliability of WSN for WSN-MCC integration
GDNF stimulates the proliferation of cultured mouse immature Sertoli cells via its receptor subunit NCAM and ERK1/2 signaling pathway
<p>Abstract</p> <p>Background</p> <p>The proliferation and final density of Sertoli cells in the testis are regulated by hormones and local factors. Glial cell line-derived neurotrophic factor (GDNF), a distantly related member of the transforming growth factor-β superfamily, and its receptor subunits GDNF family receptor alpha 1 (GFRα1), RET tyrosine kinase, and neural cell adhesion molecule (NCAM) have been reported to be expressed in the testis and involved in the regulation of proliferation of immature Sertoli cells (ISCs). However, the expression patterns of these receptor subunits and the downstream signaling pathways have not been addressed in ISCs.</p> <p>Results</p> <p>In the present study, we have reported that the proliferation of cultured ISCs was significantly enhanced by GDNF. The receptor subunits GFRα1 and NCAM but not RET were expressed in ISCs, and the stimulatory effect of GDNF on the proliferation of ISCs was significantly reduced by anti-NCAM antibody blocking or siRNA that specifically targets NCAM mRNA. Additionally, the ERK1/2 inhibitor, PD98059, completely abolished the mitogenic effect of GDNF on ISCs.</p> <p>Conclusions</p> <p>GDNF stimulates the proliferation of ISCs via its receptor subunit NCAM and the consequent activation of the ERK1/2 signaling pathway.</p
Textured BST Thin Film on Silicon Substrate: Preparation and Its Applications for High Frequency Tunable Devices
The dielectric properties of Ba0.5Sr0.5TiO3 (BST) thin films are sensitive to the relative crystallographic orientation of the films. LaNiO3 (LNO) and MgO were deposited as buffer layer on Si substrate before BST. The effect of buffer layer such as LNO, MgO and MgO/LNO bilayer on the microstructure and dielectric properties of BST were extensively investigated. The preferred (100) orientation of LNO by radio frequency (RF) magnetron sputtering was dominated by the substrate temperature and highly (100)-oriented LNO thin films were grown on Si substrates at 300°C. The oriented (100) growth of sputtered BST thin films was strongly affected by the orientation of LNO thin films and the tunability of BST thin film was greatly improved with the insertion of (100)-textured LNO buffer layer. In addition, MgO, as a buffer layer, was deposited by RF magnetron sputtering. The results show that the crystallization of BST was also enhanced by the insertion of MgO buffer layer, which enhances the oriental growth of BST along (100). Also, the tunability of the BST thin films was improved and the dielectric loss greatly decreased. Finally, CPW with BST/MgO multilayer was fabricated and the scattering (S) parameters were tested
Chinese as a Second Language Pronunciation Teaching Survey
This survey study aims to provide an overview of Chinese as a
second language (CSL) pronunciation teaching in the higher
educational institutions in the US. 80 respondents participated in and completed an online survey. The survey elicited the participants’ responses in the following constructs: the context of Chinese pronunciation teaching, the status of Chinese pronunciation teaching, the CSL learners’ motivation and goal of Chinese pronunciation teaching, approach of pinyin teaching, difficulties in segments and suprasegmentals, and issues related to the training of Chinese pronunciation teaching. Not only have the findings from the study shed new light on many important issues in Chinese pronunciation teaching, they also have important pedagogical implications for all parties in CSL teaching: learners, instructors, researchers, textbook compilers, and administrators. While this study raises more questions
than answers in Chinese pronunciation teaching, the survey highlights some critical issues that entail the joint efforts of the CSL field and points to the direction of further studies on Chinese pronunciation and Chinese pronunciation teaching
A Reusable AI-Enabled Defect Detection System for Railway Using Ensembled CNN
Accurate Defect detection is crucial for ensuring the trustworthiness of
intelligent railway systems. Current approaches rely on single deep-learning
models, like CNNs, which employ a large amount of data to capture underlying
patterns. Training a new defect classifier with limited samples often leads to
overfitting and poor performance on unseen images. To address this, researchers
have advocated transfer learning and fine-tuning the pre-trained models.
However, using a single backbone network in transfer learning still may cause
bottleneck issues and inconsistent performance if it is not suitable for a
specific problem domain. To overcome these challenges, we propose a reusable
AI-enabled defect detection approach. By combining ensemble learning with
transfer learning models (VGG-19, MobileNetV3, and ResNet-50), we improved the
classification accuracy and achieved consistent performance at a certain phase
of training. Our empirical analysis demonstrates better and more consistent
performance compared to other state-of-the-art approaches. The consistency
substantiates the reusability of the defect detection system for newly evolved
defected rail parts. Therefore we anticipate these findings to benefit further
research and development of reusable AI-enabled solutions for railway systems.Comment: 28 pages, 13 Figures, Applied Intelligence Journal, Springer Natur
Exploring User Perceptions of Virtual Reality Scene Design in Metaverse Learning Environments
Metaverse learning environments allow for a seamless and intuitive transition
between activities compared to Virtual Reality (VR) learning environments, due
to their interconnected design. The design of VR scenes is important for
creating effective learning experiences in the Metaverse. However, there is
limited research on the impact of different design elements on user's learning
experiences in VR scenes. To address this, a study was conducted with 16
participants who interacted with two VR scenes, each with varying design
elements such as style, color, texture, object, and background, while watching
a short tutorial. Participant rankings of the scenes for learning were obtained
using a seven-point Likert scale, and the Mann-Whitney U test was used to
validate differences in preference between the scenes. The results showed a
significant difference in preference between the scenes. Further analysis using
the NASA TLX questionnaire was conducted to examine the impact of this
difference on cognitive load, and participant feedback was also considered. The
study emphasizes the importance of careful VR scene design to improve the
user's learning experience.Comment: 6 pages,3 figures, accepted to present at IEEE 42nd International
Conference on Consumer Electronic
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