370 research outputs found
Distribution Aligned Diffusion and Prototype-guided network for Unsupervised Domain Adaptive Segmentation
The Diffusion Probabilistic Model (DPM) has emerged as a highly effective
generative model in the field of computer vision. Its intermediate latent
vectors offer rich semantic information, making it an attractive option for
various downstream tasks such as segmentation and detection. In order to
explore its potential further, we have taken a step forward and considered a
more complex scenario in the medical image domain, specifically, under an
unsupervised adaptation condition. To this end, we propose a Diffusion-based
and Prototype-guided network (DP-Net) for unsupervised domain adaptive
segmentation. Concretely, our DP-Net consists of two stages: 1) Distribution
Aligned Diffusion (DADiff), which involves training a domain discriminator to
minimize the difference between the intermediate features generated by the DPM,
thereby aligning the inter-domain distribution; and 2) Prototype-guided
Consistency Learning (PCL), which utilizes feature centroids as prototypes and
applies a prototype-guided loss to ensure that the segmentor learns consistent
content from both source and target domains. Our approach is evaluated on
fundus datasets through a series of experiments, which demonstrate that the
performance of the proposed method is reliable and outperforms state-of-the-art
methods. Our work presents a promising direction for using DPM in complex
medical image scenarios, opening up new possibilities for further research in
medical imaging
Branched-Chain Amino Acid Negatively Regulates KLF15 Expression via PI3K-AKT Pathway.
Recent studies have linked branched-chain amino acid (BCAA) with numerous metabolic diseases. However, the molecular basis of BCAA's roles in metabolic regulation remains to be established. KLF15 (Krüppel-like factor 15) is a transcription factor and master regulator of glycemic, lipid, and amino acids metabolism. In the present study, we found high concentrations of BCAA suppressed KLF15 expression while BCAA starvation induced KLF15 expression, suggesting KLF15 expression is negatively controlled by BCAA.Interestingly, BCAA starvation induced PI3K-AKT signaling. KLF15 induction by BCAA starvation was blocked by PI3K and AKT inhibitors, indicating the activation of PI3K-AKT signaling pathway mediated the KLF15 induction. BCAA regulated KLF15 expression at transcriptional level but not post-transcriptional level. However, BCAA starvation failed to increase the KLF15-promoter-driven luciferase expression, suggesting KLF15 promoter activity was not directly controlled by BCAA. Finally, fasting reduced BCAA abundance in mice and KLF15 expression was dramatically induced in muscle and white adipose tissue, but not in liver. Together, these data demonstrated BCAA negatively regulated KLF15 expression, suggesting a novel molecular mechanism underlying BCAA's multiple functions in metabolic regulation
Myocardial Stunning-Induced Left Ventricular Dyssynchrony On Gated Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging
Objectives Myocardial stunning provides additional nonperfusion markers of coronary artery disease (CAD), especially for severe multivessel CAD. The purpose of this study is to assess the influence of myocardial stunning to the changes of left ventricular mechanical dyssynchrony (LVMD) parameters between stress and rest gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI).
Patients and methods A total of 113 consecutive patients (88 males and 25 females) who had undergone both stress and rest 99mTc-sestamibi gated SPECT MPI were retrospectively enrolled. Suspected or known patients with CAD were included if they had exercise stress MPI and moderate to severe myocardial ischemia. Segmental scores were summed for the three main coronary arteries according to standard myocardial perfusion territories, and then regional perfusion, wall motion, and wall thickening scores were measured. Myocardial stunning was defined as both ischemia and wall dysfunction within the same coronary artery territory. Patients were divided into the stunning group (n=58) and nonstunning group (n=55).
Results There was no significant difference of LVMD parameters between stress and rest in the nonstunning group. In the stunning group, phase SD and phase histogram bandwidth of contraction were significantly larger during stress than during rest (15.05±10.70 vs. 13.23±9.01 and 46.07±34.29 vs. 41.02±32.16, PP\u3c0.05).
Conclusion Both systolic and diastolic LVMD parameters deteriorate with myocardial stunning. This kind of change may have incremental values to diagnose CAD
SunSat Design Competition 2014-2015 First Place Winner – Team CAST: Multi-Rotary Joints SPS
Space Power Satellite (SPS) is a huge spacecraft designed to collect solar energy in space for supplying electric power to the electric grid on the ground. The SPS concept was first proposed by Dr. Peter Glaser in 1968.
Various studies on SPS in various countries have been produced over the past forty years. Today, there are multiple variations on this early concept, both in innovation and in optimization. Because of the huge size, immense mass and high power of these SPS installations, there are many technological difficulties.
Here, a new Multi-Rotary Joints SPS (MR-SPS) concept is proposed. The large solar array is taken apart to illustrate the many small solar sub-arrays, and to show that each solar sub-array has two middle-power rotary joints. The extreme technical difficulty of high-power rotary joints is simplified by many middle-power rotary joints. The single-point failure problem existing in traditional SPS concept is also solved.
At the same time, the modular solar arrays can be more easily assembled in GEO where the power can best be generated and continuously transmitted. Based on our new concept, a whole system full-life NPV analysis method has been developed to evaluate the economics. Our primary results show that the investment is near 30 billion US dollars, with development and transportation costs representing the main portions. When the price of power and the development and construction costs are fixed, the cost of capital becomes an important parameter in influencing the NPV.
Click here to see the China Academy of Space Technology\u27s (CAST) video: Multi-Rotary Joints SPS - 2015 SunSat Design Competitio
NMD-12: A New Machine-Learning Derived Screening Instrument to Detect Mild Cognitive Impairment and Dementia
Introduction
Using machine learning techniques, we developed a brief questionnaire to aid neurologists and neuropsychologists in the screening of mild cognitive impairment (MCI) and dementia. Methods
With the reduction of the survey size as a goal of this research, feature selection based on information gain was performed to rank the contribution of the 45 items corresponding to patient responses to the specified questions. The most important items were used to build the optimal screening model based on the accuracy, practicality, and interpretability. The diagnostic accuracy for discriminating normal cognition (NC), MCI, very mild dementia (VMD) and dementia was validated in the test group. Results
The screening model (NMD-12) was constructed with the 12 items that were ranked the highest in feature selection. The receiver-operator characteristic (ROC) analysis showed that the area under the curve (AUC) in the test group was 0.94 for discriminating NC vs. MCI, 0.88 for MCI vs. VMD, 0.97 for MCI vs. dementia, and 0.96 for VMD vs. dementia, respectively. Discussion
The NMD-12 model has been developed and validated in this study. It provides healthcare professionals with a simple and practical screening tool which accurately differentiates NC, MCI, VMD, and dementia
How anaerobic treatment is controlling the volatile components and key odorants of purple-colored leaf tea
Special purple-colored leaf tea products rich in γ-aminobutyric acid (GABA) have recently gained popularity. Although anaerobic treatment could effectively increase the GABA content in tea products, it also imparted an unknown unpleasant aroma. This study aimed to elucidate the dynamic effects of anaerobic treatment on volatile components during the purple-colored leaf tea processing and reveal the key aroma-active components. A total of 112 volatile components were identified, and it was found that anaerobic treatment could facilitate the accumulation of 2-heptanol, (E)− 2-hexenal, ethyl salicylate, phenylethyl alcohol, and (E,E)− 2,4-decadienal, but inhibited the formation of (Z)− 3-hexenyl acetate and methyl jasmonate. Moreover, 17 potent odorants including (E)-β-ionone, linalool, hexanal, 2-heptanol, (Z)− 3-nonen-1-ol, and (E,E)− 2,4-decadienal were distinguished as the key odorants of purple-colored leaf tea products rich in GABA based on gas chromatography–olfactometry and odor activity value analysis. These results provide new insights into the effect of anaerobic treatment on tea volatile metabolites.Universidade de Vigo/CISU
Tuning Thermal Conductivity of Hybrid Perovskites through Halide Alloying
Tuning the thermal transport properties of hybrid halide perovskites is
critical for their applications in optoelectronics, thermoelectrics, and
photovoltaics. Here, we demonstrate an effective strategy to modulate the
thermal transport property of hybrid perovskites by halide alloying. A highly
tunable thermal conductivity of mixed-halide hybrid perovskites is achieved due
to halide-alloying and structural distortion. Our experimental measurements
show that the room temperature thermal conductivity of MAPb(BrxI1-x)3 (x = 0-1)
can be largely modulated from 0.27 W/mK (x = 0.5) to 0.47 W/mK (x = 1).
Molecular dynamics simulations further demonstrate that the thermal
conductivity reduction of hybrid halide perovskites results from the
suppression of the mean free paths of the low-frequency acoustic and optical
phonons. It is found that halide alloying and the induced structural distortion
can largely increase the scatterings of optical and acoustic phonons,
respectively. The confined diffusion of MA+ cations in the octahedra cage is
found to act as an additional thermal transport channel in hybrid perovskites
and can contribute around 10-20% of the total thermal conductivity. Our
findings provide a strategy for tailoring the thermal transport in hybrid
halide perovskites which may largely benefit their related applications
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