Cross-Modal Learning with 3D Deformable Attention for Action Recognition

An important challenge in vision-based action recognition is the embedding of spatiotemporal features with two or more heterogeneous modalities into a single feature. In this study, we propose a new 3D deformable transformer for action recognition with adaptive spatiotemporal receptive fields and a cross-modal learning scheme. The 3D deformable transformer consists of three attention modules: 3D deformability, local joint stride, and temporal stride attention. The two cross-modal tokens are input into the 3D deformable attention module to create a cross-attention token with a reflected spatiotemporal correlation. Local joint stride attention is applied to spatially combine attention and pose tokens. Temporal stride attention temporally reduces the number of input tokens in the attention module and supports temporal expression learning without the simultaneous use of all tokens. The deformable transformer iterates L times and combines the last cross-modal token for classification. The proposed 3D deformable transformer was tested on the NTU60, NTU120, FineGYM, and Penn Action datasets, and showed results better than or similar to pre-trained state-of-the-art methods even without a pre-training process. In addition, by visualizing important joints and correlations during action recognition through spatial joint and temporal stride attention, the possibility of achieving an explainable potential for action recognition is presented.Comment: 10 pages, 8 figure

Efficient solvent-assisted external treatment for planar heterojunction small-molecule organic solar cells

We developed a novel solvent-assisted treatment (SAT) technique to modify the nanomorphology of the planar heterojunction (PHJ) bilayer active layers (ZnPc/C-60) of organic photovoltaics (OPVs). The SAT technique uses organic solvent vapors under reduced pressures, which partially dissolves one component (the donor molecule, ZnPc, in this study) of PHJ layers prepared by vacuum deposition. Because of the partial mixing of the two layers, the PHJ layers develop a bulk heterojunction (BHJ)-like intermixed morphology. The performance of the resulting OPVs is considerably improved because of (i) the increased interfacial area of ZnPc/C-60, (ii) the healing of the intrinsic micropores within the active layers, which originate from the deposition process, and (iii) enhanced light absorption due to the rearrangement of ZnPc molecules. After the SAT, the power conversion efficiency (PCE) of OPVs improved more than three-fold (2.58%), with an open-circuit voltage (V-OC) of 0.61 V, a short-circuit current (J(SC)) of 7.50 mA cm(-2), and a fill factor (FF) of 0.56, as compared to that of the as-prepared PHJ-OPVs (PCE = 0.83%, with V-OC = 0.38 V. J(SC) = 5.3 mA cm(-2), and FF = 0.42). Our unique SAT technique provides an alternative route for controlling the nanomorphology of organic thin films by vacuum deposition, which may be very difficult to achieve using more conventional methods

High-resolution photoacoustic and ultrasound endoscope based on the transparent ultrasound transducer

Photoacoustic (PA) imaging has become one of the promising biomedical imaging technologies in the past decade, thanks to its advantages of structural, functional, imaging capabilities and seamless integration with conventional ultrasound imaging. Endoscopic photoacoustic and ultrasound (ePAUS) is the combination of PA imaging technology and endoscopic ultrasound (EUS). In the design of the ePAUS, it is ideal to align the optical beam of the laser and the acoustic beam of the transducer on the same axis to achieve high spatial resolution and long imaging range. Existing ePAUS uses a ring transducer or a beam combiner to obtain a coaxial or rather an off-axis arrangement. However, the ring transducer has a problem in that the diameter and acoustic side lobes are large, and the beam combiner has a disadvantage in that the structure is complicated and the acoustic loss due to multiple acoustic reflections is large. Our approach to solving this problem is the development of ePAUS based on a miniaturized transparent ultrasonic transducer (TUT). In this study, lead-magnesium- niobate lead-titanate and Indium Tin Oxide-based ultra-small TUT was fabricated, and the performance of center frequency of 28.1 MHz and bandwidth of 51.5% was obtained. Thereafter, quasi-focus was used by combining a multimode optical fiber and a gradient index lens, and coaxial alignment was achieved by arranging the optical axis perpendicular to the optically transparent TUT. This results in high spatial resolution and long imaging distances, and the imaging performance of the probe is demonstrated by imaging the rectum and vagina of the rat in vivo.2

Fabrication of Efficient Formamidinium Tin Iodide Perovskite Solar Cells through SnF2-Pyrazine Complex

To fabricate efficient formamidinium tin iodide (FASnI(3)) perovskite solar cells (PSCs), it is essential to deposit uniform and dense perovskite layers and reduce Sn4+ content. Here we used solvent-engineering and nonsolvent dripping process with SnF2 as an inhibitor of Sn4+. However, excess SnF2 induces phase separation on the surface of the perovskite film. In this work, we report the homogeneous dispersion of SnF2 via the formation of the SnF2-pyrazine complex. Consequently, we fabricated FASnI(3) PSCs with high reproducibility, achieving a high power conversion efficiency of 4.8%. Furthermore, the encapsulated device showed a stable performance for over 100 days, maintaining, 98% of its initial efficiency.clos

Controllable synthesis of single crystalline Sn-based oxides and their application in perovskite solar cells

We synthesized single-crystalline Sn-based oxides for use as electron-transporting layers (ETLs) in perovskite solar cells (PSCs). The control of the Zn-to-Sn cation ratio (Zn/Sn = 0-2) in a fixed concentration of hydrazine solution leads to the formation of various types of Sn-based oxides, i.e., spherical SnO2 and Zn2SnO4 nanoparticles (NPs), SnO2 nanorods, and Zn2SnO4 nanocubes. In particular, a ratio of Zn/Sn = 1 results in nanocomposites of single-crystalline SnO2 nanorods and Zn2SnO4 nanocubes. This is related to the concentration of free hydrazine unreacted with Zn and Sn ions in the reaction solution, because the resulting OH- concentration affects the growth rate of intermediate phases such as ZnSn(OH)(6), Zn(OH)(4)(2-) and Sn(OH)(6)(2-). Additionally, we propose plausible pathways for the formation of Sn-based oxides in hydrazine solution. The Sn-based oxides are applied as ETLs and annealed at a low temperature below 150 degrees C in PSCs. The PSCs fabricated by using the nanocomposite ETLs consisting of single-crystalline SnO2 nanorods and Zn2SnO4 nanocubes exhibit superior device performance to TiO2-based PSCs due to their excellent charge collection ability and optical properties, achieving a power conversion efficiency of >= 17%.clos

Fabrication of Efficient Formamidinium Tin Iodide Perovskite Solar Cells through SnF₂–Pyrazine Complex

To fabricate efficient formamidinium tin iodide (FASnI₃) perovskite solar cells (PSCs), it is essential to deposit uniform and dense perovskite layers and reduce Sn⁴⁺ content. Here we used solvent-engineering and nonsolvent dripping process with SnF₂ as an inhibitor of Sn⁴⁺. However, excess SnF₂ induces phase separation on the surface of the perovskite film. In this work, we report the homogeneous dispersion of SnF₂ via the formation of the SnF₂–pyrazine complex. Consequently, we fabricated FASnI₃ PSCs with high reproducibility, achieving a high power conversion efficiency of 4.8%. Furthermore, the encapsulated device showed a stable performance for over 100 days, maintaining 98% of its initial efficiency

Blood Test for Breast Cancer Screening through the Detection of Tumor-Associated Circulating Transcripts

Liquid biopsy has been emerging for early screening and treatment monitoring at each cancer stage. However, the current blood-based diagnostic tools in breast cancer have not been sufficient to understand patient-derived molecular features of aggressive tumors individually. Herein, we aimed to develop a blood test for the early detection of breast cancer with cost-effective and high-throughput considerations in order to combat the challenges associated with precision oncology using mRNA-based tests. We prospectively evaluated 719 blood samples from 404 breast cancer patients and 315 healthy controls, and identified 10 mRNA transcripts whose expression is increased in the blood of breast cancer patients relative to healthy controls. Modeling of the tumor-associated circulating transcripts (TACTs) is performed by means of four different machine learning techniques (artificial neural network (ANN), decision tree (DT), logistic regression (LR), and support vector machine (SVM)). The ANN model had superior sensitivity (90.2%), specificity (80.0%), and accuracy (85.7%) compared with the other three models. Relative to the value of 90.2% achieved using the TACT assay on our test set, the sensitivity values of other conventional assays (mammogram, CEA, and CA 15-3) were comparable or much lower, at 89%, 7%, and 5%, respectively. The sensitivity, specificity, and accuracy of TACTs were appreciably consistent across the different breast cancer stages, suggesting the potential of the TACTs assay as an early diagnosis and prediction of poor outcomes. Our study potentially paves the way for a simple and accurate diagnostic and prognostic tool for liquid biopsy