181 research outputs found
SVH-B interacts directly with p53 and suppresses the transcriptional activity of p53
AbstractWe previously reported that inhibition of SVH-B, a specific splicing variant of SVH, results in apoptotic cell death. In this study, we reveal that this apoptosis may be dependent on the presence of p53. Co-immunoprecipitation and GST pull-down assays have demonstrated that SVH-B directly interacts with p53. In both BEL-7404 cells and p53-null Saos-2 cells transfected with a temperature-sensitive mutant of p53, V143A, ectopically expressed SVH-B suppresses the transcriptional activity of p53, and suppression of SVH by RNA interference increases the transcriptional activity of p53. Our results suggested the function of SVH-B in accelerating growth and inhibition of apoptosis is related to its inhibitory binding to p53
Safe, Efficient, and Comfortable Velocity Control based on Reinforcement Learning for Autonomous Driving
A model used for velocity control during car following was proposed based on
deep reinforcement learning (RL). To fulfil the multi-objectives of car
following, a reward function reflecting driving safety, efficiency, and comfort
was constructed. With the reward function, the RL agent learns to control
vehicle speed in a fashion that maximizes cumulative rewards, through trials
and errors in the simulation environment. A total of 1,341 car-following events
extracted from the Next Generation Simulation (NGSIM) dataset were used to
train the model. Car-following behavior produced by the model were compared
with that observed in the empirical NGSIM data, to demonstrate the model's
ability to follow a lead vehicle safely, efficiently, and comfortably. Results
show that the model demonstrates the capability of safe, efficient, and
comfortable velocity control in that it 1) has small percentages (8\%) of
dangerous minimum time to collision values (\textless\ 5s) than human drivers
in the NGSIM data (35\%); 2) can maintain efficient and safe headways in the
range of 1s to 2s; and 3) can follow the lead vehicle comfortably with smooth
acceleration. The results indicate that reinforcement learning methods could
contribute to the development of autonomous driving systems.Comment: Submitted to IEEE transaction on IT
Attention Consistency Refined Masked Frequency Forgery Representation for Generalizing Face Forgery Detection
Due to the successful development of deep image generation technology, visual
data forgery detection would play a more important role in social and economic
security. Existing forgery detection methods suffer from unsatisfactory
generalization ability to determine the authenticity in the unseen domain. In
this paper, we propose a novel Attention Consistency Refined masked frequency
forgery representation model toward generalizing face forgery detection
algorithm (ACMF). Most forgery technologies always bring in high-frequency
aware cues, which make it easy to distinguish source authenticity but difficult
to generalize to unseen artifact types. The masked frequency forgery
representation module is designed to explore robust forgery cues by randomly
discarding high-frequency information. In addition, we find that the forgery
attention map inconsistency through the detection network could affect the
generalizability. Thus, the forgery attention consistency is introduced to
force detectors to focus on similar attention regions for better generalization
ability. Experiment results on several public face forgery datasets
(FaceForensic++, DFD, Celeb-DF, and WDF datasets) demonstrate the superior
performance of the proposed method compared with the state-of-the-art methods.Comment: The source code and models are publicly available at
https://github.com/chenboluo/ACM
Hierarchical Vector Quantized Transformer for Multi-class Unsupervised Anomaly Detection
Unsupervised image Anomaly Detection (UAD) aims to learn robust and
discriminative representations of normal samples. While separate solutions per
class endow expensive computation and limited generalizability, this paper
focuses on building a unified framework for multiple classes. Under such a
challenging setting, popular reconstruction-based networks with continuous
latent representation assumption always suffer from the "identical shortcut"
issue, where both normal and abnormal samples can be well recovered and
difficult to distinguish. To address this pivotal issue, we propose a
hierarchical vector quantized prototype-oriented Transformer under a
probabilistic framework. First, instead of learning the continuous
representations, we preserve the typical normal patterns as discrete iconic
prototypes, and confirm the importance of Vector Quantization in preventing the
model from falling into the shortcut. The vector quantized iconic prototype is
integrated into the Transformer for reconstruction, such that the abnormal data
point is flipped to a normal data point.Second, we investigate an exquisite
hierarchical framework to relieve the codebook collapse issue and replenish
frail normal patterns. Third, a prototype-oriented optimal transport method is
proposed to better regulate the prototypes and hierarchically evaluate the
abnormal score. By evaluating on MVTec-AD and VisA datasets, our model
surpasses the state-of-the-art alternatives and possesses good
interpretability. The code is available at
https://github.com/RuiyingLu/HVQ-Trans
Reflection-mode submicron-resolution in vivo photoacoustic microscopy
Submicron-resolution photoacoustic microscopy (PAM) currently exists only in transmission mode, due to the technical difficulties of combining high numerical-aperture (NA) optical illumination with high NA acoustic detection. The lateral resolution of reflection-mode PAM has not reached <2 μm in the visible light range. Here we develop the first reflection-mode submicron-resolution PAM system with a new compact design. By using a parabolic mirror to focus and reflect the photoacoustic waves, sufficient signals were collected for good sensitivity without distorting the optical focusing. By imaging nanospheres and a resolution test chart, the lateral resolution was measured to be ∼0.5 μm with an optical wavelength of 532 nm, an optical NA of 0.63. The axial resolution was measured at 15 μm. Here the axial resolution was measured by a different experiment with the lateral resolution measurement. But we didn’t describe the details of axial resolution measurement due to space limit. The maximum penetration was measured at ∼0.42 mm in optical-scattering soft tissue. As a comparison, both the submicron-resolution PAM and a 2.4 μm-resolution PAM were used to image a mouse ear in vivo with the same optical wavelength and similar pulse energy. Capillaries were resolved better by the submicron-resolution PAM. Therefore, the submicron-resolution PAM is suitable for in vivo high-resolution imaging, or even subcellular imaging, of optical absorption
Structural analysis of a novel rabbit monoclonal antibody R53 targeting an epitope in HIV-1 gp120 C4 region critical for receptor and co-receptor binding
The fourth conserved region (C4) in the HIV-1 envelope glycoprotein (Env) gp120 is a structural element that is important for its function, as it binds to both the receptor CD4 and the co-receptor CCR5/CXCR4. It has long been known that this region is highly immunogenic and that it harbors B-cell as well as T-cell epitopes. It is the target of a number of antibodies in animal studies, which are called CD4-blockers. However, the mechanism by which the virus shields itself from such antibody responses is not known. Here, we determined the crystal structure of R53 in complex with its epitope peptide using a novel anti-C4 rabbit monoclonal antibody R53. Our data show that although the epitope of R53 covers a highly conserved sequence (433)AMYAPPI(439), it is in the gp120 trimer and in the CD4-bound conformation. Our results suggest a masking mechanism to explain how HIV-1 protects this critical region from the human immune system
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