313 research outputs found
Clathrin-mediated Endocytosis with Cell Confinement and during Neutrophil Polarization
Clathrin-mediated endocytosis (CME) is one of the major pathway through which cells internalize nutrients and membrane proteins. It occurs on the membrane via clathrin-coated pits (CCPs). In this thesis, we studied CCPs' behavior when cells are under spatial constraints. In the first two projects, the constraint was applied using micro-contact printing. CCPs presented differential phenotypes on different-sized but the same shaped cells. In particular, CCPs were smaller with larger spreading area. We further showed that this might be due to the higher cortical tension associated with large spreading area. Seeding cells on anisotropic fibronectin patterns, we were able to manipulate where and how long CCPs appear on the cell. Together, these results showed that CCPs' distribution and behavior are regulated by mechanical cues in a cell.
In the last project, HL-60 differentiated neutrophils were used as the experimental system. They undergo rapid polarization in the presence of N-formylmethionyl-leucyl-phenylalanine (fMLP), during which cells not only present anisotropic morphology but also have asymetric distribution of cellular structures and signaling molecules. We found that CCPs did not have as polarized distribution upon the stimulation of fMLP, but they revealed differential interation with formyl peptitde recepter, actin, and β-arrestin with and without fMLP. Disruption of CME blocked effective neutrophil polarization as well as major signaling pathways. The results suggest a regulatory role of CME in neutrophil polarization.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/144015/1/xinyutan_1.pd
The Atomic Characterization of Weighted Local Hardy Spaces and Its Applications
The purpose of this paper is to obtain atomic decomposition characterization
of the weighted local Hardy space with
. We apply the discrete version of
Calder\'on's identity and the weighted Littlewood--Paley--Stein theory to prove
that coincides with the
weighted atomic local Hardy space
for . The atomic
decomposition theorems in our paper improve the previous atomic decomposition
results of local weighted Hardy spaces in the literature. As applications, we
derive the boundedness of inhomogeneous Calder\'on--Zygmund singular integrals
and local fractional integrals on weighted local Hardy spaces.Comment: 30 page
Small pyramidal textured ultrathin crystalline silicon solar cells with double-layer passivation
Ultrathin crystalline silicon solar cells are a promising technology roadmap to achieve more cost effectiveness. However, experimental reports on ultrathin crystalline silicon cells with thickness less than 20 μm are rare. Here, we experimentally fabricate and investigate ultrathin monocrystalline silicon solar cells consisting of 16 μm-silicon base thickness and low-cost front random pyramidal texture with the feature size of 1-2 μm. The normalized light absorption is calculated to explain the measured external quantum efficiency. The achieved efficiency is 15.1% for the single-layer passivated textured solar cell. In addition, via double-layer passivation of Al2O3/SiNx, the efficiency is further increased to 16.4% for the best textured cell, which significantly improves the absolute efficiency with Δη = 1.3%
The Construction of China’s Environmental Legislation Public Participation System
China’s environmental legislation could be enhanced by the public participation and conversation, consultation mechanism, and the mechanisms could be hearing, the legislative forum and Legislative demonstration.Key words: Environmental legislation; public participate; consultation mechanis
Scalable surface code decoders with parallelization in time
Fast classical processing is essential for most quantum fault-tolerance
architectures. We introduce a sliding-window decoding scheme that provides fast
classical processing for the surface code through parallelism. Our scheme
divides the syndromes in spacetime into overlapping windows along the time
direction, which can be decoded in parallel with any inner decoder. With this
parallelism, our scheme can solve the decoding throughput problem as the code
scales up, even if the inner decoder is slow. When using min-weight perfect
matching and union-find as the inner decoders, we observe circuit-level
thresholds of and , respectively, which are almost identical
to and for the batch decoding.Comment: Main text: 6 pages, 3 figures. Supplementary material: 18 pages, 14
figures. V2: added data and updated general formalis
LightRW: FPGA Accelerated Graph Dynamic Random Walks
Graph dynamic random walks (GDRWs) have recently emerged as a powerful
paradigm for graph analytics and learning applications, including graph
embedding and graph neural networks. Despite the fact that many existing
studies optimize the performance of GDRWs on multi-core CPUs, massive random
memory accesses and costly synchronizations cause severe resource
underutilization, and the processing of GDRWs is usually the key performance
bottleneck in many graph applications. This paper studies an alternative
architecture, FPGA, to address these issues in GDRWs, as FPGA has the ability
of hardware customization so that we are able to explore fine-grained pipeline
execution and specialized memory access optimizations. Specifically, we propose
{LightRW}, a novel FPGA-based accelerator for GDRWs. LightRW embraces a series
of optimizations to enable fine-grained pipeline execution on the chip and to
exploit the massive parallelism of FPGA while significantly reducing memory
accesses. As current commonly used sampling methods in GDRWs do not efficiently
support fine-grained pipeline execution, we develop a parallelized reservoir
sampling method to sample multiple vertices per cycle for efficient pipeline
execution. To address the random memory access issues, we propose a
degree-aware configurable caching method that buffers hot vertices on-chip to
alleviate random memory accesses and a dynamic burst access engine that
efficiently retrieves neighbors. Experimental results show that our
optimization techniques are able to improve the performance of GDRWs on FPGA
significantly. Moreover, LightRW delivers up to 9.55x and 9.10x speedup over
the state-of-the-art CPU-based MetaPath and Node2vec random walks,
respectively. This work is open-sourced on GitHub at
https://github.com/Xtra-Computing/LightRW.Comment: Accepted to SIGMOD 202
NBMOD: Find It and Grasp It in Noisy Background
Grasping objects is a fundamental yet important capability of robots, and
many tasks such as sorting and picking rely on this skill. The prerequisite for
stable grasping is the ability to correctly identify suitable grasping
positions. However, finding appropriate grasping points is challenging due to
the diverse shapes, varying density distributions, and significant differences
between the barycenter of various objects. In the past few years, researchers
have proposed many methods to address the above-mentioned issues and achieved
very good results on publicly available datasets such as the Cornell dataset
and the Jacquard dataset. The problem is that the backgrounds of Cornell and
Jacquard datasets are relatively simple - typically just a whiteboard, while in
real-world operational environments, the background could be complex and noisy.
Moreover, in real-world scenarios, robots usually only need to grasp fixed
types of objects. To address the aforementioned issues, we proposed a
large-scale grasp detection dataset called NBMOD: Noisy Background Multi-Object
Dataset for grasp detection, which consists of 31,500 RGB-D images of 20
different types of fruits. Accurate prediction of angles has always been a
challenging problem in the detection task of oriented bounding boxes. This
paper presents a Rotation Anchor Mechanism (RAM) to address this issue.
Considering the high real-time requirement of robotic systems, we propose a
series of lightweight architectures called RA-GraspNet (GraspNet with Rotation
Anchor): RARA (network with Rotation Anchor and Region Attention), RAST
(network with Rotation Anchor and Semi Transformer), and RAGT (network with
Rotation Anchor and Global Transformer) to tackle this problem. Among them, the
RAGT-3/3 model achieves an accuracy of 99% on the NBMOD dataset. The NBMOD and
our code are available at https://github.com/kmittle/Grasp-Detection-NBMOD
Cold atmospheric plasma induces apoptosis in human colon and lung cancer cells through modulating mitochondrial pathway
Cold atmospheric plasma (CAP) is an emerging and promising oncotherapy with considerable potential and advantages that traditional treatment modalities lack. The objective of this study was to investigate the effect and mechanism of plasma-inhibited proliferation and plasma-induced apoptosis on human lung cancer and colon cancer cells in vitro and in vivo. Piezobrush® PZ2, a handheld CAP unit based on the piezoelectric direct discharge technology, was used to generate and deliver non-thermal plasma. Firstly, CAPPZ2 treatment inhibited the proliferation of HT29 colorectal cancer cells and A549 lung cancer cells using CCK8 assay, caused morphological changes at the cellular and subcellular levels using transmission electron microscopy, and suppressed both types of tumor cell migration and invasion using the Transwell migration and Matrigel invasion assay. Secondly, we confirmed plasma-induced apoptosis in the HT29 and A549 cells using the AO/EB staining coupled with flow cytometry, and verified the production of apoptosis-related proteins, such as cytochrome c, PARP, cleaved caspase-3 and caspase-9, Bcl-2 and Bax, using western blotting. Finally, the aforementioned in vitro results were tested in vivo using cell-derived xenograft mouse models, and the anticancer effect was confirmed and attributed to CAP-mediated apoptosis. The immunohistochemical analysis revealed that the expression of cleaved caspase-9, caspase-3, PARP and Bax were upregulated whereas that of Bcl-2 downregulated after CAP treatment. These findings collectively suggest that the activation of the mitochondrial pathway is involved during CAPPZ2-induced apoptosis of human colon and lung cancer cells in vitro and in vivo
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