219 research outputs found
FedA3I: Annotation Quality-Aware Aggregation for Federated Medical Image Segmentation against Heterogeneous Annotation Noise
Federated learning (FL) has emerged as a promising paradigm for training
segmentation models on decentralized medical data, owing to its
privacy-preserving property. However, existing research overlooks the prevalent
annotation noise encountered in real-world medical datasets, which limits the
performance ceilings of FL. In this paper, we, for the first time, identify and
tackle this problem. For problem formulation, we propose a contour evolution
for modeling non-independent and identically distributed (Non-IID) noise across
pixels within each client and then extend it to the case of multi-source data
to form a heterogeneous noise model (i.e., Non-IID annotation noise across
clients). For robust learning from annotations with such two-level Non-IID
noise, we emphasize the importance of data quality in model aggregation,
allowing high-quality clients to have a greater impact on FL. To achieve this,
we propose Federated learning with Annotation quAlity-aware AggregatIon, named
FedA3I, by introducing a quality factor based on client-wise noise estimation.
Specifically, noise estimation at each client is accomplished through the
Gaussian mixture model and then incorporated into model aggregation in a
layer-wise manner to up-weight high-quality clients. Extensive experiments on
two real-world medical image segmentation datasets demonstrate the superior
performance of FedAI against the state-of-the-art approaches in dealing
with cross-client annotation noise. The code is available at
https://github.com/wnn2000/FedAAAI.Comment: Accepted at AAAI'2
C2FTrans: Coarse-to-Fine Transformers for Medical Image Segmentation
Convolutional neural networks (CNN), the most prevailing architecture for
deep-learning based medical image analysis, are still functionally limited by
their intrinsic inductive biases and inadequate receptive fields. Transformer,
born to address this issue, has drawn explosive attention in natural language
processing and computer vision due to its remarkable ability in capturing
long-range dependency. However, most recent transformer-based methods for
medical image segmentation directly apply vanilla transformers as an auxiliary
module in CNN-based methods, resulting in severe detail loss due to the rigid
patch partitioning scheme in transformers. To address this problem, we propose
C2FTrans, a novel multi-scale architecture that formulates medical image
segmentation as a coarse-to-fine procedure. C2FTrans mainly consists of a
cross-scale global transformer (CGT) which addresses local contextual
similarity in CNN and a boundary-aware local transformer (BLT) which overcomes
boundary uncertainty brought by rigid patch partitioning in transformers.
Specifically, CGT builds global dependency across three different small-scale
feature maps to obtain rich global semantic features with an acceptable
computational cost, while BLT captures mid-range dependency by adaptively
generating windows around boundaries under the guidance of entropy to reduce
computational complexity and minimize detail loss based on large-scale feature
maps. Extensive experimental results on three public datasets demonstrate the
superior performance of C2FTrans against state-of-the-art CNN-based and
transformer-based methods with fewer parameters and lower FLOPs. We believe the
design of C2FTrans would further inspire future work on developing efficient
and lightweight transformers for medical image segmentation. The source code of
this paper is publicly available at https://github.com/xianlin7/C2FTrans
SAMUS: Adapting Segment Anything Model for Clinically-Friendly and Generalizable Ultrasound Image Segmentation
Segment anything model (SAM), an eminent universal image segmentation model,
has recently gathered considerable attention within the domain of medical image
segmentation. Despite the remarkable performance of SAM on natural images, it
grapples with significant performance degradation and limited generalization
when confronted with medical images, particularly with those involving objects
of low contrast, faint boundaries, intricate shapes, and diminutive sizes. In
this paper, we propose SAMUS, a universal model tailored for ultrasound image
segmentation. In contrast to previous SAM-based universal models, SAMUS pursues
not only better generalization but also lower deployment cost, rendering it
more suitable for clinical applications. Specifically, based on SAM, a parallel
CNN branch is introduced to inject local features into the ViT encoder through
cross-branch attention for better medical image segmentation. Then, a position
adapter and a feature adapter are developed to adapt SAM from natural to
medical domains and from requiring large-size inputs (1024x1024) to small-size
inputs (256x256) for more clinical-friendly deployment. A comprehensive
ultrasound dataset, comprising about 30k images and 69k masks and covering six
object categories, is collected for verification. Extensive comparison
experiments demonstrate SAMUS's superiority against the state-of-the-art
task-specific models and universal foundation models under both task-specific
evaluation and generalization evaluation. Moreover, SAMUS is deployable on
entry-level GPUs, as it has been liberated from the constraints of long
sequence encoding. The code, data, and models will be released at
https://github.com/xianlin7/SAMUS
Effects of Root-Zone Temperature and N, P, and K Supplies on Nutrient Uptake of Cucumber (Cucumis sativus L.) Seedlings in Hydroponics
The nutrient uptake and allocation of cucumber (Cucumis sativus L.) seedlings at different root-zone temperatures (RZT) and different concentrations of nitrogen (N), phosphorus (P), and potassium (K) nutrients were examined. Plants were grown in a nutrient solution for 30 d at two root-zone temperatures (a diurnally fluctuating ambient 10°C-RZT and a constant 20° C-RZT) with the aerial parts of the plants maintained at ambient temperature (10°C -30°C). Based on a Hoagland nutrient solution, seven N, P, and K nutrient concentrations were supplied to the plants at each RZT. Results showed that total plant and shoot dry weights under each nutrient treatment were significantly lower at low root-zone temperature (10°C-RZT) than at elevated root-zone temperature (20°C-RZT). But higher root dry weights were obtained at 10°C-RZT than those at 20°C-RZT. Total plant dry weights at both 10°C-RZT and 20°C-RZT were increased with increased solution N concentration, but showed different responses under P and K treatments. All estimated nutrient concentrations (N, P, and K) and uptake by the plant were obviously influenced by RZT. Low root temperature (10°C-RZT) caused a remarkable reduction in total N, P, and K uptake of shoots in all nutrient treatments, and more nutrients were accumulated in roots at 10 degrees C-RZT than those at 20°C-RZT. N, P, and K uptakes and distribution ratios in shoots were both improved at elevated root-zone temperature (20° C-RZT). N supplies were favorable to P and K uptake at both 10°C-RZT and 20°C-RZT, with no significantly positive correlation between N and P, or N and K uptake. In conclusion, higher RZT was more beneficial to increase of plant biomass and mineral nutrient absorption than was increase of nutrient concentration. Among the three element nutrients, increasing N nutrient concentration in solution promoted better tolerance to low RZT in cucumber seedlings than increasing P and K. In addition, appropriately decreased P concentration favors plant growth
Does the Short Term Fluctuation of Mineral Element Concentrations in the Closed Hydroponic Experimental Facilities Affect the Mineral Concentrations in Cucumber Plants Exposed to Elevated CO\u3csub\u3e2\u3c/sub\u3e?
Aims
Studies dealing with plants’ mineral nutrient status under elevated atmospheric CO2concentration (eCO2) are usually conducted in closed hydroponic systems, in which nutrient solutions are entirely renewed every several days. Here, we investigated the contribution of the fluctuation of concentrations of N ([N]), P ([P]), and K ([K]) in nutrient solutions in this short period on their concentrations in cucumber plants exposed to different [CO2] and N levels. Methods
Cucumber (Cucumis sativus L.) plants were hydroponically grown under two [CO2] and three N levels. [N], [P], and [K] in nutrient solutions and cucumber plants were analyzed. Results
The transpiration rate (Tr) was significantly inhibited by eCO2, whereas Tr per plant was increased due to the larger leaf area. Elevated [CO2] significantly decreased [N] in low N nutrient solutions, which imposed an additional decrease in [N] in plants. [P] in nutrient solutions fluctuated slightly, so the change of [P] in plants might be attributed to the dilution effect and the demand change under eCO2. [K] in moderate and high N nutrient solutions were significantly decreased, which exacerbated the [K] decrease in plants under eCO2. Conclusions
The short-term fluctuation of [N] and [K] in nutrient solutions is caused by the asynchronous uptakes of N, K, and water under eCO2, which has an appreciable influence on [N] and [K] in plants besides the dilution effect. This defect of the closed hydroponic system may let us exaggerate the negative impact of eCO2 itself on [N] and [K] in plants
Federated Learning with Imbalanced and Agglomerated Data Distribution for Medical Image Classification
Federated learning (FL), training deep models from decentralized data without
privacy leakage, has drawn great attention recently. Two common issues in FL,
namely data heterogeneity from the local perspective and class imbalance from
the global perspective have limited FL's performance. These two coupling
problems are under-explored, and existing few studies may not be sufficiently
realistic to model data distributions in practical sceneries (e.g. medical
sceneries). One common observation is that the overall class distribution
across clients is imbalanced (e.g. common vs. rare diseases) and data tend to
be agglomerated to those more advanced clients (i.e., the data agglomeration
effect), which cannot be modeled by existing settings. Inspired by real medical
imaging datasets, we identify and formulate a new and more realistic data
distribution denoted as L2 distribution where global class distribution is
highly imbalanced and data distributions across clients are imbalanced but
forming a certain degree of data agglomeration. To pursue effective FL under
this distribution, we propose a novel privacy-preserving framework named FedIIC
that calibrates deep models to alleviate bias caused by imbalanced training. To
calibrate the feature extractor part, intra-client contrastive learning with a
modified similarity measure and inter-client contrastive learning guided by
shared global prototypes are introduced to produce a uniform embedding
distribution of all classes across clients. To calibrate the classification
heads, a softmax cross entropy loss with difficulty-aware logit adjustment is
constructed to ensure balanced decision boundaries of all classes. Experimental
results on publicly-available datasets demonstrate the superior performance of
FedIIC in dealing with both the proposed realistic modeling and the existing
modeling of the two coupling problems
Interactive Effects of the CO\u3csub\u3e2\u3c/sub\u3e Enrichment and Nitrogen Supply on the Biomass Accumulation, Gas Exchange Properties, and Mineral Elements Concentrations in Cucumber Plants at Different Growth Stages
The concentration changes of mineral elements in plants at different CO2 concentrations ([CO2]) and nitrogen (N) supplies and the mechanisms which control such changes are not clear. Hydroponic trials on cucumber plants with three [CO2] (400, 625, and 1200 µmol mol−1) and five N supply levels (2, 4, 7, 14, and 21 mmol L−1) were conducted. When plants were in high N supply, the increase in total biomass by elevated [CO2] was 51.7% and 70.1% at the seedling and initial fruiting stages, respectively. An increase in net photosynthetic rate (Pn) by more than 60%, a decrease in stomatal conductance (Gs) by 21.2–27.7%, and a decrease in transpiration rate (Tr) by 22.9–31.9% under elevated [CO2] were also observed. High N supplies could further improve the Pn and offset the decrease of Gs and Tr by elevated [CO2]. According to the mineral concentrations and the correlation results, we concluded the main factors affecting these changes. The dilution effect was the main factor driving the reduction of all mineral elements, whereas Tr also had a great impact on the decrease of [N], [K], [Ca], and [Mg] except [P]. In addition, the demand changes of N, Ca, and Mg influenced the corresponding element concentrations in cucumber plants
Sleep duration in Chinese adolescents: biological, environmental, and behavioral predictors
AbstractObjectiveTo examine sleep duration-related risk factors from multidimensional domains among Chinese adolescents.MethodsA random sample of 4801 adolescents aged 11–20 years participated in a cross-sectional survey. A self-reported questionnaire was used to collect information about the adolescents' sleep behaviors and possible related factors from eight domains.ResultsIn all, 51.0% and 9.8% of adolescents did not achieve optimal sleep duration (defined as <8.0 h per day) on weekdays and on weekends, respectively. According to multivariate logistic regression models, after adjusting for all possible confounders, 17 factors were associated with sleep duration <8 h. Specifically, 13 factors from five domains were linked to physical and psychosocial condition, environment, and behaviors. These factors were overweight/obesity, chronic pain, bedtime anxiety/excitement/depression, bed/room sharing, school starting time earlier than 07:00, cram school learning, more time spent on homework on weekdays, television viewing ≥2 h/day, physical activity <1 h/day, irregular bedtime, and shorter sleep duration of father.ConclusionBiological and psychosocial conditions, sleep environments, school schedules, daily activity and behaviors, and parents' sleep habits significantly may affect adolescents' sleep duration, indicating that the existing chronic sleep loss in adolescents could be, at least partly, intervened by improving adolescents' physical and psychosocial conditions, controlling visual screen exposure, regulating school schedules, improving sleep hygiene and daytime behaviors, and changing parents' sleep habits
Bisacurone gel ameliorated burn wounds in experimental rats via its anti-inflammatory, antioxidant, and angiogenic properties
ABSTRACT Purpose: To investigate putative mechanism of wound healing for chitosan-based bisacurone gel against secondary burn wounds in rats. Methods: A second-degree burn wound with an open flame using mixed fuel (2 mL, 20 seconds) was induced in Sprague Dawley rats (male, 180-220 g, n = 15, each) followed by topical treatments with either vehicle control (white petroleum gel, 1%), silver sulfadiazine (1%) or bisacurone gel (2.5, 5, or 10%) for 20 days. Wound contraction rate and paw withdrawal threshold were monitored on various days. Oxidative stress (superoxide dismutase, glutathione, malondialdehyde, and nitric oxide), pro-inflammatory cytokines (tumour necrosis factor-alpha, interleukins by enzyme-linked immunosorbent assay), growth factors (transforming growth factor-β, vascular endothelial growth factor C using real time polymerase chain reaction and Western blot assay) levels, and histology of wound skin were assessed at the end. Results: Bisacurone gel showed 98.72% drug release with a 420.90–442.70 cps viscosity. Bisacurone gel (5 and 10%) significantly (p < 0.05) improved wound contraction rate and paw withdrawal threshold. Bisacurone gel attenuated oxidative stress, pro-inflammatory cytokines, and water content. It also enhanced angiogenesis (hydroxyproline and growth factor) and granulation in wound tissue than vehicle control. Conclusions: These findings suggested that bisacurone gel can be a potential candidate to treat burn wounds via its anti-inflammatory, antioxidant, and angiogenic properties
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