170 research outputs found
Can We Solve 3D Vision Tasks Starting from A 2D Vision Transformer?
Vision Transformers (ViTs) have proven to be effective, in solving 2D image
understanding tasks by training over large-scale image datasets; and meanwhile
as a somehow separate track, in modeling the 3D visual world too such as voxels
or point clouds. However, with the growing hope that transformers can become
the "universal" modeling tool for heterogeneous data, ViTs for 2D and 3D tasks
have so far adopted vastly different architecture designs that are hardly
transferable. That invites an (over-)ambitious question: can we close the gap
between the 2D and 3D ViT architectures? As a piloting study, this paper
demonstrates the appealing promise to understand the 3D visual world, using a
standard 2D ViT architecture, with only minimal customization at the input and
output levels without redesigning the pipeline. To build a 3D ViT from its 2D
sibling, we "inflate" the patch embedding and token sequence, accompanied with
new positional encoding mechanisms designed to match the 3D data geometry. The
resultant "minimalist" 3D ViT, named Simple3D-Former, performs surprisingly
robustly on popular 3D tasks such as object classification, point cloud
segmentation and indoor scene detection, compared to highly customized
3D-specific designs. It can hence act as a strong baseline for new 3D ViTs.
Moreover, we note that pursing a unified 2D-3D ViT design has practical
relevance besides just scientific curiosity. Specifically, we demonstrate that
Simple3D-Former naturally enables to exploit the wealth of pre-trained weights
from large-scale realistic 2D images (e.g., ImageNet), which can be plugged in
to enhancing the 3D task performance "for free"
Taking a Respite from Representation Learning for Molecular Property Prediction
Artificial intelligence (AI) has been widely applied in drug discovery with a
major task as molecular property prediction. Despite the boom of AI techniques
in molecular representation learning, some key aspects underlying molecular
property prediction haven't been carefully examined yet. In this study, we
conducted a systematic comparison on three representative models, random
forest, MolBERT and GROVER, which utilize three major molecular
representations, extended-connectivity fingerprints, SMILES strings and
molecular graphs, respectively. Notably, MolBERT and GROVER, are pretrained on
large-scale unlabelled molecule corpuses in a self-supervised manner. In
addition to the commonly used MoleculeNet benchmark datasets, we also assembled
a suite of opioids-related datasets for downstream prediction evaluation. We
first conducted dataset profiling on label distribution and structural
analyses; we also examined the activity cliffs issue in the opioids-related
datasets. Then, we trained 4,320 predictive models and evaluated the usefulness
of the learned representations. Furthermore, we explored into the model
evaluation by studying the effect of statistical tests, evaluation metrics and
task settings. Finally, we dissected the chemical space generalization into
inter-scaffold and intra-scaffold generalization and measured prediction
performance to evaluate model generalizbility under both settings. By taking
this respite, we reflected on the key aspects underlying molecular property
prediction, the awareness of which can, hopefully, bring better AI techniques
in this field
Point Contrastive Prediction with Semantic Clustering for Self-Supervised Learning on Point Cloud Videos
We propose a unified point cloud video self-supervised learning framework for
object-centric and scene-centric data. Previous methods commonly conduct
representation learning at the clip or frame level and cannot well capture
fine-grained semantics. Instead of contrasting the representations of clips or
frames, in this paper, we propose a unified self-supervised framework by
conducting contrastive learning at the point level. Moreover, we introduce a
new pretext task by achieving semantic alignment of superpoints, which further
facilitates the representations to capture semantic cues at multiple scales. In
addition, due to the high redundancy in the temporal dimension of dynamic point
clouds, directly conducting contrastive learning at the point level usually
leads to massive undesired negatives and insufficient modeling of positive
representations. To remedy this, we propose a selection strategy to retain
proper negatives and make use of high-similarity samples from other instances
as positive supplements. Extensive experiments show that our method outperforms
supervised counterparts on a wide range of downstream tasks and demonstrates
the superior transferability of the learned representations.Comment: Accepted by ICCV 202
Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos
Recently, the community has made tremendous progress in developing effective
methods for point cloud video understanding that learn from massive amounts of
labeled data. However, annotating point cloud videos is usually notoriously
expensive. Moreover, training via one or only a few traditional tasks (e.g.,
classification) may be insufficient to learn subtle details of the
spatio-temporal structure existing in point cloud videos. In this paper, we
propose a Masked Spatio-Temporal Structure Prediction (MaST-Pre) method to
capture the structure of point cloud videos without human annotations. MaST-Pre
is based on spatio-temporal point-tube masking and consists of two
self-supervised learning tasks. First, by reconstructing masked point tubes,
our method is able to capture the appearance information of point cloud videos.
Second, to learn motion, we propose a temporal cardinality difference
prediction task that estimates the change in the number of points within a
point tube. In this way, MaST-Pre is forced to model the spatial and temporal
structure in point cloud videos. Extensive experiments on MSRAction-3D,
NTU-RGBD, NvGesture, and SHREC'17 demonstrate the effectiveness of the proposed
method.Comment: Accepted by ICCV 202
Molecular cloning and in silico analysis of the duck (Anas platyrhynchos) MEF2A gene cDNA and its expression profile in muscle tissues during fetal development
The role of myogenic enhancer transcription factor 2a (MEF2A) in avian muscle during fetal development is unknown. In this work, we cloned the duck MEF2A cDNA sequence (GenBank accession no. HM460752) and examined its developmental expression profiles in cardiac muscle, non-vascular smooth muscle and skeletal muscle. Duck MEF2A cDNA comprised 1479 bp encoding 492 amino acid residues. In silico analysis showed that MEF2A contained MADS (MCM1, AGAMOUS, DEFICIENS and SRF - serum response factor), MEF2 and mitogen-activated protein kinase (MAPK) transcription domains with high homology to related proteins in other species. Modified sites in these domains were conserved among species and several variants were found. Quantitative PCR showed that MEF2A was expressed in all three muscles at each developmental stage examined, with the expression in smooth muscle being higher than in the other muscles. These results indicate that the conserved domains of duck MEF2A, including the MADS and MEF2 domains, are important for MEF2A transcription factor function. The expression of MEF2A in duck smooth muscle and cardiac muscle suggests that MEF2A plays a role in these two tissues
Case Report: Camrelizumab combined with gemcitabine and oxaliplatin in the treatment of advanced intrahepatic cholangiocarcinoma: a case report and literature review
Intrahepatic cholangiocarcinoma (ICC) is one of the most common invasive malignant tumors, with a 5-year survival rate of less than 5%. Currently, radical surgical resection is the preferred treatment for ICC. However, most patients are only diagnosed at an advanced stage and are therefore not eligible for surgery. Herein, we present a case of advanced ICC in which radical surgery was not possible due to tumor invasion of the second porta hepatis and right hepatic artery. Six treatment cycles with a gemcitabine and oxaliplatin (GEMOX) regimen combined with camrelizumab immunotherapy achieved a partial response and successful tumor conversion, as tumor invasion of the second porta hepatis and right hepatic artery was no longer evident. The patient subsequently underwent successful radical surgical resection, including hepatectomy, caudate lobe resection, and cholecystectomy combined with lymph node dissection. Cases of patients with advanced ICC undergoing surgical resection after combined immunotherapy and chemotherapy are rare. The GEMOX regimen combined with camrelizumab demonstrated favorable antitumor efficacy and safety, suggesting that it might be a potential feasible and safe conversion therapy strategy for patients with advanced ICC
Construction of a eukaryotic expression vector for pEGFP-FST and its biological activity in duck myoblasts
Background: Follistatin (FST), a secreted glycoprotein, is
intrinsically linked to muscle hypertrophy. To explore the function of
duck FST in myoblast proliferation and differentiation, the pEGFP-FST
eukaryotic expression vector was constructed and identified. The
biological activities of this vector were analyzed by transfecting
pEGFP-FST into cultured duck myoblasts using Lipofectamine\u2122 2000
and subsequently determining the mRNA expression profiles of FST and
myostatin (MSTN). Results: The duck pEGFP-FST vector was successfully
constructed and was confirmed to have high liposome-mediated
transfection efficiency in duck myoblasts. Additionally, myoblasts
transfected with pEGFP-FST had a higher biological activity.
Significantly, the overexpression of FST in these cells significantly
inhibited the mRNA expression of MSTN (a target gene that is negatively
regulated by FST). Conclusions: The duck pEGFP-FST vector has been
constructed successfully and exhibits biological activity by promoting
myoblast proliferation and differentiation in vitro
The relationship between frequent premature ventricular complexes and epicardial adipose tissue volume
BackgroundEpicardial adipose tissue (EAT) is related to atrial fibrillation. The association between EAT volume and premature ventricular complexes (PVCs) remains unclear. Our study aimed to investigate the effect of EAT volume on the risk of frequent PVCs and burden levels of PVCs.MethodsThis observational study retrospectively recruited consecutive patients who had consultation between 2019 and 2021 at the First Affiliated Hospital of Zhengzhou University. Frequent PVC patients (n = 402) and control patients (n = 402) undergoing non-contrast computed tomography (CT) were enrolled. We selected evaluation criteria for the conduct of a 1:1 propensity score matching (PSM) analysis. Multivariable logistic analysis was used to investigate factors related to frequent PVCs. Furthermore, the determinants of EAT volume and the burden levels of PVCs were evaluated.ResultsPatients with PVCs had a significantly larger EAT volume than control patients. EAT volume was significantly larger in male PVC patients with BMI ≥24 kg/m2, diabetes mellitus, and E/A ratio <1. EAT volume was independently associated with PVCs. Moreover, the larger EAT volume was an independent predictor for the high burden level of PVCs. We revealed that the risk of high PVC burden level was increased with the rising of EAT volume by restricted cubic splines.ConclusionsEAT volume was larger in frequent PVC patients than in control patients, regardless of other confounding factors. A large EAT volume was independently associated with high burden levels of PVCs. EAT volume may be a new mechanism to explain the pathogenesis of PVCs
Indigo: a natural molecular passivator for efficient perovskite solar cells
Organic–inorganic hybrid lead halide perovskite solar cells have made unprecedented progress in improving photovoltaic efficiency during the past decade, while still facing critical stability challenges. Herein, the natural organic dye Indigo is explored for the first time to be an efficient molecular passivator that assists in the preparation of high-quality hybrid perovskite film with reduced defects and enhanced stability. The Indigo molecule with both carbonyl and amino groups can provide bifunctional chemical passivation for defects. In-depth theoretical and experimental studies show that the Indigo molecules firmly binds to the perovskite surfaces, enhancing the crystallization of perovskite films with improved morphology. Consequently, the Indigo-passivated perovskite film exhibits increased grain size with better uniformity, reduced grain boundaries, lowered defect density, and retarded ion migration, boosting the device efficiency up to 23.22%, and ˜21% for large-area device (1 cm2). Furthermore, the Indigo passivation can enhance device stability in terms of both humidity and thermal stress. These results provide not only new insights into the multipassivation role of natural organic dyes but also a simple and low-cost strategy to prepare high-quality hybrid perovskite films for optoelectronic applications based on Indigo derivatives.Peer ReviewedPostprint (author's final draft
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