6 research outputs found
DualToken-ViT: Position-aware Efficient Vision Transformer with Dual Token Fusion
Self-attention-based vision transformers (ViTs) have emerged as a highly
competitive architecture in computer vision. Unlike convolutional neural
networks (CNNs), ViTs are capable of global information sharing. With the
development of various structures of ViTs, ViTs are increasingly advantageous
for many vision tasks. However, the quadratic complexity of self-attention
renders ViTs computationally intensive, and their lack of inductive biases of
locality and translation equivariance demands larger model sizes compared to
CNNs to effectively learn visual features. In this paper, we propose a
light-weight and efficient vision transformer model called DualToken-ViT that
leverages the advantages of CNNs and ViTs. DualToken-ViT effectively fuses the
token with local information obtained by convolution-based structure and the
token with global information obtained by self-attention-based structure to
achieve an efficient attention structure. In addition, we use position-aware
global tokens throughout all stages to enrich the global information, which
further strengthening the effect of DualToken-ViT. Position-aware global tokens
also contain the position information of the image, which makes our model
better for vision tasks. We conducted extensive experiments on image
classification, object detection and semantic segmentation tasks to demonstrate
the effectiveness of DualToken-ViT. On the ImageNet-1K dataset, our models of
different scales achieve accuracies of 75.4% and 79.4% with only 0.5G and 1.0G
FLOPs, respectively, and our model with 1.0G FLOPs outperforms LightViT-T using
global tokens by 0.7%
Polymersomes with aggregation-induced emission based on amphiphilic block copolypeptoids
International audienc
Fe<sup>3+</sup>@polyDOPA‑<i>b</i>‑polysarcosine, a T<sub>1</sub>‑Weighted MRI Contrast Agent via Controlled NTA Polymerization
α-Amino acid <i>N</i>-thiocarboxyanhydrides (NTAs)
are promising cyclic monomers to synthesize polypeptides and polypeptoids
via controlled ring-opening polymerizations. Superior to <i>N</i>-carboxyanhydrides requiring protection on hydroxyl groups, NTAs
are able to tolerate such nucleophiles. In this work, we report the
synthesis of NTA monomers containing unprotected phenolic hydroxyl
groups of 3,4-dihydroxy-l-phenylalanine (DOPA) and l-tyrosine (Tyr). Their controlled ROPs and sequential copolymerizations
with polysarcosine (PSar) yield PDOPA, PTyr, and PDOPA-<i>b</i>-polysarcosine (PDOPA-<i>b</i>-PSar) products quantitatively
with designable degrees of polymerization. Micellar nanoparticles
of Fe<sup>3+</sup>@PDOPA-<i>b</i>-PSar have been prepared
thanks to the strong chelation of ironÂ(III) cation by catechol ligands
that act as T1-weighted magnetic resonance imaging (MRI) contrast
agents. For instance, Fe<sup>3+</sup>@PDOPA<sub>10</sub>-<i>b</i>-PSar<sub>50</sub> exhibits higher longitudinal relaxivity (<i>r</i><sub>1</sub> = 5.6 mM<sup>–1</sup> s<sup>–1</sup>) than commercial Gd<sup>3+</sup>-based compounds. Effective MRI
contrast enhancement in vivo of nude mice with a moderate duration
(150 min) and 3D magnetic resonance angiography in rabbit illustrated
by using volume rendering and maximal intensity projection techniques
ignite the clinical application of Fe<sup>3+</sup>-based polypeptÂ(o)Âides
in diagnostic radiology as Gd-free MRI contrast agents
Fe<sup>3+</sup>@polyDOPA‑<i>b</i>‑polysarcosine, a T<sub>1</sub>‑Weighted MRI Contrast Agent via Controlled NTA Polymerization
α-Amino acid <i>N</i>-thiocarboxyanhydrides (NTAs)
are promising cyclic monomers to synthesize polypeptides and polypeptoids
via controlled ring-opening polymerizations. Superior to <i>N</i>-carboxyanhydrides requiring protection on hydroxyl groups, NTAs
are able to tolerate such nucleophiles. In this work, we report the
synthesis of NTA monomers containing unprotected phenolic hydroxyl
groups of 3,4-dihydroxy-l-phenylalanine (DOPA) and l-tyrosine (Tyr). Their controlled ROPs and sequential copolymerizations
with polysarcosine (PSar) yield PDOPA, PTyr, and PDOPA-<i>b</i>-polysarcosine (PDOPA-<i>b</i>-PSar) products quantitatively
with designable degrees of polymerization. Micellar nanoparticles
of Fe<sup>3+</sup>@PDOPA-<i>b</i>-PSar have been prepared
thanks to the strong chelation of ironÂ(III) cation by catechol ligands
that act as T1-weighted magnetic resonance imaging (MRI) contrast
agents. For instance, Fe<sup>3+</sup>@PDOPA<sub>10</sub>-<i>b</i>-PSar<sub>50</sub> exhibits higher longitudinal relaxivity (<i>r</i><sub>1</sub> = 5.6 mM<sup>–1</sup> s<sup>–1</sup>) than commercial Gd<sup>3+</sup>-based compounds. Effective MRI
contrast enhancement in vivo of nude mice with a moderate duration
(150 min) and 3D magnetic resonance angiography in rabbit illustrated
by using volume rendering and maximal intensity projection techniques
ignite the clinical application of Fe<sup>3+</sup>-based polypeptÂ(o)Âides
in diagnostic radiology as Gd-free MRI contrast agents