108 research outputs found
Characteristics’ relation model of asphalt pavement performance based on factor analysis
Pavement performance of asphalt is an important criterion for road engineering quality evaluation. Proposed research paper designed an orthogonal experiment using three asphalt mixtures, including SMA-13, AC-20 and ATB-25 to get their relation models and evaluate pavement performances. Totally twenty-seven samples from private companies have been selected and seven crucial parameters are analyzed via factor analysis. Further analysis concluded three main factors corresponding to the three main pavement performance parameters (i) high-temperature stability (ii) durability and (iii) shear resistance. Based on scores of each asphalt mixture’s 3D scatter-map is plotted. Analysis found the relationship between three above-mentioned parameters. Relationship between the three main performance parameters has been established using graphical analysis. A separation plane can define the different types of asphalt mixtures’ scatter distribution area, and get the regression equation for the plane. Based on the equation for the plane a more intuitionistic model has been made which describes the relationship of asphalt pavement performance. Keywords: Road engineering, Asphalt, Index correlation, Surface fitting, 3D-mode
Numerical Simulation of the Effect of Temperature- dependent Acoustic and Thermal Parameters on the Focal Temperature and Thermal Lesion of Biological Tissue Irradiated by HIFU
Introduction: Accurate temperature and thermal lesion prediction is very important for high-intensity focused ultrasound (HIFU) in the treatment of tumors. The traditional focal temperature and thermal lesion prediction methods usually use constant acoustic and thermal parameters. However, HIFU irradiation of biological tissue will cause its temperature rise and change the tissue characteristic parameters, which will affect the sound field and temperature field.Material and Methods: The constant acoustic and thermal parameters, dynamic acoustic and thermal parameters, constant acoustic and dynamic thermal parameters, dynamic acoustic and constant thermal parameters were used for simulation by Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation and Pennes biological heat transfer equation (PBHTE), and their effects and differences on the focal temperature and thermal lesion of biological tissue were compared and analyzed.Results: The focal temperature predicted by constant acoustic parameters was less than that predicted by dynamic acoustic parameters, and the thermal lesion area predicted by constant acoustic parameters was also smaller than that predicted by dynamic acoustic parameters. On the premise of using dynamic acoustic parameters, the focal temperature predicted by dynamic thermal parameters was higher than that predicted by constant thermal parameters. When the acoustic parameters remained constant, the focal temperature predicted by dynamic thermal parameters was lower than that predicted by constant thermal parameters, but their predicted thermal lesion areas were almost the same.Conclusion: The temperature-dependent acoustic and thermal parameters should be considered when predicting focal temperature and thermal lesion of biological tissue, so that doctors can use the appropriate thermal dose in the surgical treatment of HIFU
Stability of lineage-specific attributes in senescent human peripheral glia
Senescent and non-senescent human Schwann cells (hSCs) established in culture are virtually undistinguishable without the aid of specific tests such as detection of senescence-associated β-galactosidase (SA-βGal) activity. In most cultures, the rate of cell division is maintained high up until the second passage but cells cease to proliferate rapidly thereafter and the populations become senescent. By passage-5 no further expansion is possible and the cells manifest abnormalities such as vacuolization of the cytoplasm, aberrant nuclei (including multinucleation), and clustering. Arrival to senescence in hSC populations cannot be prevented by overexpression of hTERT and indefectibly occur under standard culture conditions regardless of the age of the donor. Even though senescent hSCs remain viable for prolonged periods of time, it is unclear whether they maintain attributes specific to cells of the SC lineage. To address this question, we performed a careful analysis of the progression of hSCs towards senescence to evaluate changes in proliferation rates, viability, purity and expression of SC-specific markers. We also obtained the transcriptomes of hSCs collected at different rounds of subculture and performed a stringent bioinformatics analysis to identify SC-specific and regulatory genes. We found that the hSC transcriptome was very stable and that hSCs maintained their expected identity (or transcriptional signature) regardless of subculture and the continued influence of mitogenic factors. Strikingly, the transcriptomes of low passage (proliferative) and late passage (senescent) hSCs were essentially undistinguishable with the exception of <100 differentially expressed genes known to play a role in replicative senescence, cell cycle arrest, chromatin organization and telomere maintenance. Senescent hSCs expressed invariable levels of SC-specific markers such as S100β and aligned to each other forming typical bundles at confluency. Most importantly, they maintained their ability to engulf and digest myelin granules, which is a function proper of SCs during nerve repair. To conclude, our studies show the value of combining transcriptomics (RNAseq) profiling and cell-based assays to understand hSC senescence. The stability of the hSC transcriptome in the face of expansion and mitogenic stimulation adds a level of safety for the use of these glial cells in autotransplantation therapy.Fil: Monje, Paula. Indiana University. School of Medicine; Estados UnidosFil: Andersen, Natalia Denise. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. University of Miami; Estados UnidosFil: Sant, David. University of Miami; Estados UnidosFil: Peng, Kevin. Indiana University. School of Medicine; Estados UnidosFil: Wang, Gaofeng. University of Miami; Estados UnidosFil: Xu, Xiao-Ming. Indiana University. School of Medicine; Estados UnidosXV European Meetingon Glial Cells in Health and DiseaseMarseillesFranciaEuropean Glial Meetin
A Novel Macroblock Level Rate Control Method for Stereo Video Coding
To compress stereo video effectively, this paper proposes a novel macroblock (MB) level rate control method based on binocular perception. A binocular just-notification difference (BJND) model based on the parallax matching is first used to describe binocular perception. Then, the proposed rate control method is performed in stereo video coding with four levels, namely, view level, group-of-pictures (GOP) level, frame level, and MB level. In the view level, different proportions of bitrates are allocated for the left and right views of stereo video according to the prestatistical rate allocation proportion. In the GOP level, the total number of bitrates allocated to each GOP is computed and the initial quantization parameter of each GOP is set. In the frame level, the target bits allocated to each frame are computed. In the MB level, visual perception factor, which is measured by the BJND value of MB, is used to adjust the MB level bit allocation, so that the rate control results in line with the human visual characteristics. Experimental results show that the proposed method can control the bitrate more accurately and get better subjective quality of stereo video, compared with other methods
Expanding Language-Image Pretrained Models for General Video Recognition
Contrastive language-image pretraining has shown great success in learning
visual-textual joint representation from web-scale data, demonstrating
remarkable "zero-shot" generalization ability for various image tasks. However,
how to effectively expand such new language-image pretraining methods to video
domains is still an open problem. In this work, we present a simple yet
effective approach that adapts the pretrained language-image models to video
recognition directly, instead of pretraining a new model from scratch. More
concretely, to capture the long-range dependencies of frames along the temporal
dimension, we propose a cross-frame attention mechanism that explicitly
exchanges information across frames. Such module is lightweight and can be
plugged into pretrained language-image models seamlessly. Moreover, we propose
a video-specific prompting scheme, which leverages video content information
for generating discriminative textual prompts. Extensive experiments
demonstrate that our approach is effective and can be generalized to different
video recognition scenarios. In particular, under fully-supervised settings,
our approach achieves a top-1 accuracy of 87.1% on Kinectics-400, while using
12 times fewer FLOPs compared with Swin-L and ViViT-H. In zero-shot
experiments, our approach surpasses the current state-of-the-art methods by
+7.6% and +14.9% in terms of top-1 accuracy under two popular protocols. In
few-shot scenarios, our approach outperforms previous best methods by +32.1%
and +23.1% when the labeled data is extremely limited. Code and models are
available at https://aka.ms/X-CLIPComment: Accepted by ECCV2022, Ora
Elucidating the dynamic immune responses within the ocular mucosa of rainbow trout (Oncorhynchus mykiss) after infection with Flavobacterium columnare
The eye of vertebrates is constantly faced with numerous challenges from aquatic or airborne pathogens. As a crucial first line of defense, the ocular mucosa (OM) protects the visual organ from external threats in vertebrates such as birds and mammals. However, the understanding of ocular mucosal immunity in early vertebrates, such as teleost fish, remains limited, particularly concerning their resistance to bacterial infections. To gain insights into the pivotal role of the OM in antibacterial immunity among teleost fish, we developed a bacterial infection model using Flavobacterium columnare in rainbow trout (Oncorhynchus mykiss). Here the qPCR and immunofluorescence results showed that F. columnare could invade trout OM, suggesting that the OM could be a primary target and barrier for the bacteria. Moreover, immune-related genes (il-6, il-8, il-11, cxcl10, nod1, il1-b, igm, igt, etc.) were upregulated in the OM of trout following F. columnare infection, as confirmed by qPCR, which was further proved through RNA-seq. The results of transcriptome analyses showed that bacterial infection critically triggers a robust immune response, including innate, and adaptive immune-related signaling pathways such as Toll-like, NOD-like, and C-type lectin receptor signaling pathway and immune network for IgA production, which underscores the immune role of the OM in bacterial infection. Interestingly, a substantial reduction in the expression of genes associated with visual function was observed after infection, indicating that bacterial infection could impact ocular function. Overall, our findings have unveiled a robust mucosal immune response to bacterial infection in the teleost OM for the first time, providing valuable insights for future research into the mechanisms and functions of ocular mucosal immunity in early vertebrate species
- …