139 research outputs found
Multi Task Consistency Guided Source-Free Test-Time Domain Adaptation Medical Image Segmentation
Source-free test-time adaptation for medical image segmentation aims to
enhance the adaptability of segmentation models to diverse and previously
unseen test sets of the target domain, which contributes to the
generalizability and robustness of medical image segmentation models without
access to the source domain. Ensuring consistency between target edges and
paired inputs is crucial for test-time adaptation. To improve the performance
of test-time domain adaptation, we propose a multi task consistency guided
source-free test-time domain adaptation medical image segmentation method which
ensures the consistency of the local boundary predictions and the global
prototype representation. Specifically, we introduce a local boundary
consistency constraint method that explores the relationship between tissue
region segmentation and tissue boundary localization tasks. Additionally, we
propose a global feature consistency constraint toto enhance the intra-class
compactness. We conduct extensive experiments on the segmentation of benchmark
fundus images. Compared to prediction directly by the source domain model, the
segmentation Dice score is improved by 6.27\% and 0.96\% in RIM-ONE-r3 and
Drishti GS datasets, respectively. Additionally, the results of experiments
demonstrate that our proposed method outperforms existing competitive domain
adaptation segmentation algorithms.Comment: 31 pages,7 figure
PL-CVIO: Point-Line Cooperative Visual-Inertial Odometry
Low-feature environments are one of the main Achilles' heels of geometric
computer vision (CV) algorithms. In most human-built scenes often with low
features, lines can be considered complements to points. In this paper, we
present a multi-robot cooperative visual-inertial navigation system (VINS)
using both point and line features. By utilizing the covariance intersection
(CI) update within the multi-state constraint Kalman filter (MSCKF) framework,
each robot exploits not only its own point and line measurements, but also
constraints of common point and common line features observed by its neighbors.
The line features are parameterized and updated by utilizing the Closest Point
representation. The proposed algorithm is validated extensively in both
Monte-Carlo simulations and a real-world dataset. The results show that the
point-line cooperative visual-inertial odometry (PL-CVIO) outperforms the
independent MSCKF and our previous work CVIO in both low-feature and
rich-feature environments
High-Throughput Screening of Transition Metal Single-Atom Catalysts for Nitrogen Reduction Reaction
The discovery of metals as catalytic centers for nitrogen reduction reactions
has stimulated great enthusiasm for single-atom catalysts. However, the poor
activity and low selectivity of available SACs are far away from the industrial
requirement. Through the high throughout first principles calculations, the
doping engineering can effectively regulate the NRR performance of b-Sb
monolayer. Especially, the origin of activated N2 is revealed from the
perspective of the electronic structure of the active center. Among the 24
transition metal dopants, Re@Sb and Tc@Sb showed the best NRR catalytic
performance with a low limiting potential. The Re@Sb and Tc@Sb also could
significantly inhibit HER and achieve a high theoretical Faradaic efficiency of
100%. Our findings not only accelerate discovery of catalysts for ammonia
synthesis but also contribute to further elucidate the structure-performance
correlations
YOLObile: Real-Time Object Detection on Mobile Devices via Compression-Compilation Co-Design
The rapid development and wide utilization of object detection techniques
have aroused attention on both accuracy and speed of object detectors. However,
the current state-of-the-art object detection works are either
accuracy-oriented using a large model but leading to high latency or
speed-oriented using a lightweight model but sacrificing accuracy. In this
work, we propose YOLObile framework, a real-time object detection on mobile
devices via compression-compilation co-design. A novel block-punched pruning
scheme is proposed for any kernel size. To improve computational efficiency on
mobile devices, a GPU-CPU collaborative scheme is adopted along with advanced
compiler-assisted optimizations. Experimental results indicate that our pruning
scheme achieves 14 compression rate of YOLOv4 with 49.0 mAP. Under our
YOLObile framework, we achieve 17 FPS inference speed using GPU on Samsung
Galaxy S20. By incorporating our proposed GPU-CPU collaborative scheme, the
inference speed is increased to 19.1 FPS, and outperforms the original YOLOv4
by 5 speedup. Source code is at:
\url{https://github.com/nightsnack/YOLObile}
Myeloid Hypoxia-Inducible Factor HIF1A Provides Cardio-Protection During Ischemia and Reperfusion
The transcription factor hypoxia-inducible factor HIF1A induces cardioprotection from ischemia and reperfusion injury. Here, we investigate tissue-specific pathways that are critical for HIF1A-elicited tissue protection. Initial studies showed that mice with induced global Hif1a deletion (Hif1aloxP/loxP UbiquitinCre+) have exaggerated myocardial injury during in situ ischemia and reperfusion. Surprisingly, this phenotype was mirrored only in mice with myeloid-specific Hif1a deletion (Hif1aloxP/loxP LysM Cre+). In contrast, mice with myocardial specific (Hif1aloxP/loxP Myosin Cre+), or vascular Hif1a deletion (Hif1aloxP/loxP VEcadherin Cre+) experienced similar levels of injury as controls. Subsequent studies using adoptive transfer of Hif1a-deficient polymorphonuclear neutrophils (PMNs) prior to myocardial injury demonstrated increased reperfusion injury. On the contrary, the adoptive transfer of PMNs treated ex vivo with the hypoxia inducible factor (HIF) stabilizer dimethyloxalylglycine (DMOG) was associated with attenuated myocardial injury. Furthermore, DMOG-mediated cardioprotection was abolished in Hif1aloxP/loxP LysM Cre+ mice, but not in Hif2aloxP/loxP LysM Cre+ mice. Finally, studies of PMN-dependent HIF1A target genes implicated the neuronal guidance molecule netrin-1 in mediating the cardioprotective effects of myeloid HIF1A. Taken together, the present studies identified a functional role for myeloid-expressed HIF1A in providing cardioprotection during ischemia and reperfusion injury, which is mediated, at least in part, by the induction of the netrin-1 neuronal guidance molecule in neutrophils
Terahertz Radiation from Combined Metallic Slit Arrays
We report an approach to efficiently generate terahertz radiation from a combined periodic structure. The proposed configuration is composed of two metallic slit arrays deliberately designed with different periodic length, slit width and depth. We found that the combination of the two slit arrays could provide special electromagnetic modes, which exhibit nonradiative property above the surface of one slit array and radiative property inside the other one. An electron beam holding proper energy could resonate with those modes to generate strong and directional electromagnetic radiations in the terahertz regime, indicating that the approach has the potential in developing high-performance terahertz radiation sources
Transcriptional Responses of Different Brain Cell Types to Oxygen Decline
Brain hypoxia is associated with a wide range of physiological and clinical conditions. Although oxygen is an essential constituent of maintaining brain functions, our understanding of how specific brain cell types globally respond and adapt to decreasing oxygen conditions is incomplete. In this study, we exposed mouse primary neurons, astrocytes, and microglia to normoxia and two hypoxic conditions and obtained genome-wide transcriptional profiles of the treated cells. Analysis of differentially expressed genes under conditions of reduced oxygen revealed a canonical hypoxic response shared among different brain cell types. In addition, we observed a higher sensitivity of neurons to oxygen decline, and dissected cell type-specific biological processes affected by hypoxia. Importantly, this study establishes novel gene modules associated with brain cells responding to oxygen deprivation and reveals a state of profound stress incurred by hypoxia
Unveiling the origin of catalytic sites of Pt nanoparticles decorated on oxygen-deficient vanadium-doped cobalt hydroxide nanosheet for hybrid sodium-air batteries
Highly active bifunctional electrocatalysts are crucial for improving the performance of rechargeable metal-air batteries. However, most reported bifunctional electrocatalysts feature poor electrocatalytic activity and stability toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Here, we have reported the first-ever study of an effective one-step reduction-assisted exfoliation method to exfoliate bulk vanadium-doped cobalt hydroxide (V-doped Co(OH)2, denoted as V-Co(OH)2) into ultrathin nanosheets with abundant oxygen vacancies (V-Co(OH)2-Ov) and simultaneously anchor them with highly dispersed ultrafine Pt nanoparticles (NPs) with a nominal size of 0.8-2.4 nm (denoted as Pt/V-Co(OH)2-Ov). The Pt/V-Co(OH)2-Ov catalyst exhibits improved catalytic performance in ORR/OER. X-ray absorption spectroscopy analysis and theoretical calculations reveal the strong interfacial electronic interactions between Pt NPs and V-Co(OH)2-Ov, which synergistically improves oxygen intermediates' adsorption/desorption, enhancing the ORR and OER performance. Using Pt/V-Co(OH)2-Ov as a catalyst in the air cathode, a hybrid sodium-air battery displays a record value of an ultralow charging-discharging voltage gap of 0.07 V at a current density of 0.01 mA cm-2 with remarkable stability of up to 1000 cycles. This reduction-assisted exfoliation approach provides a new strategy to generate oxygen vacancies in metal hydroxides, which act as anchoring sites for deposition of sub-nanometal NPs via a strong interfacial effect
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