The vector hydrophone can simultaneously measure the sound pressure and particle vibration velocity in the sound field, and its dipole directivity can overcome the ambiguity of port and starboard. In ...the isotropic noise field, the vector hydrophone can obtain a combined gain of 3-4.8dB. In general, vector hydrophones are often applied in the form of an array, which is ideal deep-sea acoustic equipment. Array gain describes the improvement of output signal-to-noise ratio (SNR) of an array compared with the input SNR of a single element, which reflects the sonar target detection performance to some extent. In this paper, we make full use of the multi-channel output of the vector hydrophone vertical array (VHVA). Combined with the sound pressure-vibration velocity joint processing technology, we discuss the additional gain for different vector combinations. The trial results of a 16-element VHVA in the South China Sea validate that the array gain of VHVA can be significantly increased by 2-3dB compared with the traditional sound pressure hydrophone vertical array. The research results in this paper provide a new idea for improving the target detection performance for VHVA.
Micro-ultrasound (micro-US) is a novel 29-MHz ultrasound technique that provides 3-4 times higher resolution than traditional ultrasound, potentially enabling low-cost, accurate diagnosis of prostate ...cancer. Accurate prostate segmentation is crucial for prostate volume measurement, cancer diagnosis, prostate biopsy, and treatment planning. However, prostate segmentation on micro-US is challenging due to artifacts and indistinct borders between the prostate, bladder, and urethra in the midline. This paper presents MicroSegNet, a multi-scale annotation-guided transformer UNet model designed specifically to tackle these challenges. During the training process, MicroSegNet focuses more on regions that are hard to segment (hard regions), characterized by discrepancies between expert and non-expert annotations. We achieve this by proposing an annotation-guided binary cross entropy (AG-BCE) loss that assigns a larger weight to prediction errors in hard regions and a lower weight to prediction errors in easy regions. The AG-BCE loss was seamlessly integrated into the training process through the utilization of multi-scale deep supervision, enabling MicroSegNet to capture global contextual dependencies and local information at various scales. We trained our model using micro-US images from 55 patients, followed by evaluation on 20 patients. Our MicroSegNet model achieved a Dice coefficient of 0.939 and a Hausdorff distance of 2.02 mm, outperforming several state-of-the-art segmentation methods, as well as three human annotators with different experience levels. Our code is publicly available at https://github.com/mirthAI/MicroSegNet and our dataset is publicly available at https://zenodo.org/records/10475293.
A novel red long-lasting phosphor CaAl2Si2O8:Mn2+ was successfully synthesized by sol-gel method. X-ray diffractometer(XRD) and fluorescence spectrometer were used to characterize the structure and ...photoluminescence of the persistent phosphors, respectively. Under UV light irradiation, this phosphor showed obvious long-lasting phosphorescence that can be clearly seen with naked eyes in a dark room for 18 min after the irradiation source has been removed. Thermoluminescence measurement showed that the phosphor has an appropriate energy depth of 0.43 ev.
A fast method for detecting minority structures in a graph Zhou, Fangfang; Chen, Qi'an; Cui, Yunlong ...
Proceedings of the 13th International Symposium on Visual Information Communication and Interaction,
12/2020
Conference Proceeding
A graph contains plentiful structures. Some minority structures are important, such as high degree nodes and bridges. Detecting these minority structures is beneficial to accelerate computational ...graph analysis and improve the comprehension of graph visualization. Regarding four typical minority structures, this paper proposes two algorithms to detect these structures fast and efficiently. A set of experiments demonstrate the effectiveness of the proposed algorithms.
The chiral edge current is the boundary manifestation of the Chern number of
a quantum anomalous Hall (QAH) insulator. Its direct observation is assumed to
require well-quantized Hall conductance, ...and is so far lacking. The recently
discovered van der Waals antiferromagnet MnBi$_2$Te$_4$ is theorized as a QAH
in odd-layers but has shown Hall resistivity below the quantization value at
zero magnetic field. Here, we perform scanning superconducting quantum
interference device (sSQUID) microscopy on these seemingly failed QAH
insulators to image their current distribution. When gated to the charge
neutral point, our device exhibits edge current, which flows unidirectionally
on the odd-layer boundary both with vacuum and with the even-layer. The
chirality of such edge current reverses with the magnetization of the bulk.
Surprisingly, we find the edge channels coexist with finite bulk conduction
even though the bulk chemical potential is in the band gap, suggesting their
robustness under significant edge-bulk scattering. Our result establishes the
existence of chiral edge currents in a topological antiferromagnet and offers
an alternative for identifying QAH states.
Denoising diffusion probabilistic models (DDPMs) have achieved unprecedented success in computer vision. However, they remain underutilized in medical imaging, a field crucial for disease diagnosis ...and treatment planning. This is primarily due to the high computational cost associated with (1) the use of large number of time steps (e.g., 1,000) in diffusion processes and (2) the increased dimensionality of medical images, which are often 3D or 4D. Training a diffusion model on medical images typically takes days to weeks, while sampling each image volume takes minutes to hours. To address this challenge, we introduce Fast-DDPM, a simple yet effective approach capable of improving training speed, sampling speed, and generation quality simultaneously. Unlike DDPM, which trains the image denoiser across 1,000 time steps, Fast-DDPM trains and samples using only 10 time steps. The key to our method lies in aligning the training and sampling procedures. We introduced two efficient noise schedulers with 10 time steps: one with uniform time step sampling and another with non-uniform sampling. We evaluated Fast-DDPM across three medical image-to-image generation tasks: multi-image super-resolution, image denoising, and image-to-image translation. Fast-DDPM outperformed DDPM and current state-of-the-art methods based on convolutional networks and generative adversarial networks in all tasks. Additionally, Fast-DDPM reduced training time by a factor of 5 and sampling time by a factor of 100 compared to DDPM. Our code is publicly available at: https://github.com/mirthAI/Fast-DDPM.
Boundary helical Luttinger liquid (HLL) with broken bulk time-reversal symmetry belongs to a unique topological class which may occur in antiferromagnets (AFM). Here, we search for signatures of HLL ...on the edge of a recently discovered topological AFM, MnBi2Te4 even-layer. Using scanning superconducting quantum interference device, we directly image helical edge current in the AFM ground state appearing at its charge neutral point. Such helical edge state accompanies an insulating bulk which is topologically distinct from the ferromagnetic Chern insulator phase as revealed in a magnetic field driven quantum phase transition. The edge conductance of the AFM order follows a power-law as a function of temperature and source-drain bias which serves as strong evidence for HLL. Such HLL scaling is robust at finite fields below the quantum critical point. The observed HLL in a layered AFM semiconductor represents a highly tunable topological matter compatible with future spintronics and quantum computation.
AIM: TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) has been reported to specifically induce apoptosis of cancer cells although only a small percentage of cell lines were sensitive ...to it. Cell lines not responding to TRAIL in vitro were said to be more prone to apoptosis when TRAIL was combined with another anticancer agent.Generally, factors affecting drug-sensitivity involve many apoptosis-related proteins, including p53. The expression of wild-type p53 gene was proposed as an important premise for tumor cells responding to chemotherapy. The present study was to investigate the cell killing action of TRAIL on colon cancer cell line SW480, its synergistic effect with doxorubicin, and the possible mechanisms.METHODS: SW480 cells were cultured in the regular condition and incubated with different levels of agents.Morphologic changes in these cells after treatment were observed under phase-contrast microscope and cytotoxicity by TRAIL alone and in combination with doxorubicin was quantified by a 1-day microculture tetrazolium dye (MTT) assay. In addition, flow cytometry assay (FCM) and transmission electron microscopy were used to detect apoptosis among these cells. Variation of p53 protein level among different groups according to concentrations of agents was measured by Western blot assay.RESULTS: (1) SW480 cells were not sensitive to TRAIL,with IC50>l mg·L^1 and dose-independent cytotoxicity. (2)SW480 cells were sensitive to doxorubicin at a certain degree,with dose-dependent cytotoxicity and IC50=65.25±3.48μmol·L^-1. (3) TRAIL could synergize with doxorubicin to kill SW480 cells effectively, which was represented by the boosted killing effect of doxorubicin on theses cells. IC50 of doxorubicin against SW480 cells sharply reduced when it was combined with TRAIL. (4) Subtoxic TRAIL (100 μg·L^-1),combined with subtoxic doxorubicin (0.86 μmol·L^-1), could kill SW480 cells sufficiently. Cytotoxicity by MTT assay arrived at 80.12±2.67 %, which was significantly higher than that by TRAIL or doxorubicin alone, with P=0.006 and 0.003 respectively. This killing effect was partly due to apoptosis. It was proved by large amounts of apoptotic cells under phase-contrast microscopy, cell apoptosis rate of 76.82±1.93 % by FCM assay and typical apoptotic morphology observed through transmission electron microscopy. Increase of apoptosis after combined treatment had no relation with protein level of p53 (p>0.05).CONCLUSION: SW480 cells are not sensitive to TRAIL, but TRAIL can synergize with lower concentra~on of doxorubidn to induce apoptosis effectively. The status of p53 protein is not involved in the mechanism of synergistic apoptosis. It suggests the potential therapeutic applicability of the combination of TRAIL with doxorubidn against colon cancers.
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