Channel prior convolutional attention for medical image segmentation

Characteristics such as low contrast and significant organ shape variations are often exhibited in medical images. The improvement of segmentation performance in medical imaging is limited by the generally insufficient adaptive capabilities of existing attention mechanisms. An efficient Channel Prior Convolutional Attention (CPCA) method is proposed in this paper, supporting the dynamic distribution of attention weights in both channel and spatial dimensions. Spatial relationships are effectively extracted while preserving the channel prior by employing a multi-scale depth-wise convolutional module. The ability to focus on informative channels and important regions is possessed by CPCA. A segmentation network called CPCANet for medical image segmentation is proposed based on CPCA. CPCANet is validated on two publicly available datasets. Improved segmentation performance is achieved by CPCANet while requiring fewer computational resources through comparisons with state-of-the-art algorithms. Our code is publicly available at \url{https://github.com/Cuthbert-Huang/CPCANet}

A single dose of DNA vaccine based on conserved H5N1 subtype proteins provides protection against lethal H5N1 challenge in mice pre-exposed to H1N1 influenza virus

<p>Abstract</p> <p>Background</p> <p>Highly pathogenic avian influenza virus subtype H5N1 infects humans with a high fatality rate and has pandemic potential. Vaccination is the preferred approach for prevention of H5N1 infection. Seasonal influenza virus infection has been reported to provide heterosubtypic immunity against influenza A virus infection to some extend. In this study, we used a mouse model pre-exposed to an H1N1 influenza virus and evaluated the protective ability provided by a single dose of DNA vaccines encoding conserved H5N1 proteins.</p> <p>Results</p> <p>SPF BALB/c mice were intranasally infected with A/PR8 (H1N1) virus beforehand. Six weeks later, the mice were immunized with plasmid DNA expressing H5N1 virus NP or M1, or with combination of the two plasmids. Both serum specific Ab titers and IFN-γ secretion by spleen cells in vitro were determined. Six weeks after the vaccination, the mice were challenged with a lethal dose of H5N1 influenza virus. The protective efficacy was judged by survival rate, body weight loss and residue virus titer in lungs after the challenge. The results showed that pre-exposure to H1N1 virus could offer mice partial protection against lethal H5N1 challenge and that single-dose injection with NP DNA or NP + M1 DNAs provided significantly improved protection against lethal H5N1 challenge in mice pre-exposed to H1N1 virus, as compared with those in unexposed mice.</p> <p>Conclusions</p> <p>Pre-existing immunity against seasonal influenza viruses is useful in offering protection against H5N1 infection. DNA vaccination may be a quick and effective strategy for persons innaive to influenza A virus during H5N1 pandemic.</p

Productivity Evaluation Method of Horizontal Well Volume Fracturing in Tight Oil Reservoir

Tight oil resources in north Songliao basin is rich and abundant, which is the most important energy sources foundation of stable and raising oil production in Daqing oil field. However, it is difficult to develop such oil resources by the regular ways for the poor reservoir property and thin reservoir thickness. Using the way of horizontal well by volume fracturing can increase contract area of well and the reservoir, improve reservoir flow performance and reach the high oil production, which has showed good results up till now. The accurate productivity evaluation of volume fracturing horizontal well is an important content of reservoir and production engineering field, which is also to develop solutions and decision-making basis. The current formula of horizontal well in low permeability reservoirs production did not consider the effect of seepage volume form fracturing, so it is poorly adapt to calculate the productivity of volume fracturing horizontal well. Based on the tight oil reservoir geological characteristics and seepage characteristics, equation are solved coupling with flow through fractures in the substrate, productivity prediction model is established and the innovation is based on considering horizontal well reservoir heterogeneity, fracturing scale and any artificial fracture distribution form, the results of which can provides a reliable theoretical basis for tight oil reservoir developed effectively

Mechanistic Insights Into the Interaction Between Transcription Factors and Epigenetic Modifications and the Contribution to the Development of Obesity

Objective: The development of obesity is inseparable from genetic and epigenetic factors, and transcription factors (TFs) play an essential role in these two mechanisms. This review analyzes the interaction of TFs with epigenetic modifications and the epigenetic mechanisms underlying peroxisome proliferator-activated receptor (PPAR)γ, an important transcription factor, in the development of obesity.Methods: We describe the relationship between TFs and different epigenetic modifications and illustrate the several mechanisms described. Next, we summarize the epigenetic mechanisms of PPARs, an important class of transcription factors involved in obesity, that induce obesity with different triggering factors. Finally, we discuss the mechanisms of epigenetic modification of PPAR-related ligands in lipid metabolism and propose future avenues of research.Results: TFs participate in epigenetic modifications in different forms, causing changes in gene expression. The interactions between the different epigenetic modifications and PPARs are important biological developments that affect fat tissue differentiation, lipogenesis, and lipid metabolism, thereby inducing or inhibiting the development of obesity. We then highlight the need for more research to understand the role of epigenetic modifications and PPARs.Conclusions: Epigenetic mechanisms involved in the regulation of PPARs may be excellent therapeutic targets for obesity treatment. However, there is a need for a deeper understanding of how PPARs and other obesity-related transcription factors interact with epigenetic modifications

The Influences of Drought and Land-Cover Conversion on Inter-Annual Variation of NPP in the Three-North Shelterbelt Program Zone of China Based on MODIS Data

Terrestrial ecosystems greatly contribute to carbon (C) emission reduction targets through photosynthetic C uptake.Net primary production (NPP) represents the amount of atmospheric C fixed by plants and accumulated as biomass. The Three-North Shelterbelt Program (TNSP) zone accounts for more than 40% of China’s landmass. This zone has been the scene of several large-scale ecological restoration efforts since the late 1990s, and has witnessed significant changes in climate and human activities.Assessing the relative roles of different causal factors on NPP variability in TNSP zone is very important for establishing reasonable local policies to realize the emission reduction targets for central government. In this study, we examined the relative roles of drought and land cover conversion(LCC) on inter-annual changes of TNSP zone for 2001–2010. We applied integrated correlation and decomposition analyses to a Standardized Evapotranspiration Index (SPEI) and MODIS land cover dataset. Our results show that the 10-year average NPP within this region was about 420 Tg C. We found that about 60% of total annual NPP over the study area was significantly correlated with SPEI (p<0.05). The LCC-NPP relationship, which is especially evident for forests in the south-central area, indicates that ecological programs have a positive impact on C sequestration in the TNSP zone. Decomposition analysis generally indicated that the contributions of LCC, drought, and other Natural or Anthropogenic activities (ONA) to changes in NPP generally had a consistent distribution pattern for consecutive years. Drought and ONA contributed about 74% and 23% to the total changes in NPP, respectively, and the remaining 3% was attributed to LCC. Our results highlight the importance of rainfall supply on NPP variability in the TNSP zone

Occurrence of multi-mycotoxin in paddy rice in Guangdong Province

Objective To understand the contamination pattern of mycotoxin in paddy rice in the main rice-growing regions of Guangdong Province, and analyze the distribution difference of mycotoxin in different areas, so as to provide basis for the implementation of precise prevention and control measures. Methods A total of 120 paddy rice samples were collected from eight cities in the Pearl River Delta, northern, eastern and western Guangdong during 2018 and 2019, and were analyzed for 16 mycotoxins by multiple reaction monitoring mode of ultra performance liquid chromatography-tandem mass spectrometer. Results Among the 120 paddy rice samples, 19.17% (23/120) were positive for mycotoxins, and the main polluants were aflatoxins and fumonisins. FB1 were detected in 9.17% (11/120) of the samples, followed by 8.33% (10/120) for AFB1. Two samples had the AFB1 concentrations above the tolerance limit of 10 μg/kg. The detection values were 73.90 and 18.80 μg/kg, respectively. Among 6 trichothecene mycotoxins, only deoxynivalenol (1.67%, 2/120) and its acetyl derivatives[0.83% (1/120) for 3-Ac-DON and 0.83% (1/120) for 15-Ac-DON] were found. ZEN was found in 3.33% (4/120) of the samples. Additionally, 1.67% (2/120) of the paddy rice samples were positive for sterigmatocystin. The ochratoxin A, nivalenol, T-2 and HT-2 mycotoxins were not found in the paddy rice samples. The co-occurrence of two or more mycotoxins was confirmed in 8.33% (10/120) of the paddy rice samples, mainly combination was AFB1 and other mycotoxins. The contamination patterns were different in the eight cities. The paddy rice samples from Zhanjiang was mainly contaminated by FB1, FB2, DON and 3-Ac-DON. Samples from Heyuan were mainly contaminated by AFB1, AFB2, sterigmatocystin, FB1 and FB2. The concentration levels of ZEN, DON and 3-Ac-DON were relatively higher in samples from Shaoguan. Conclusion The paddy rice samples from Guangdong Province were contaminated by multiple mycotoxins, and the pollution patterns were different in different areas. In terms of the co-occurence of mycotoxins, some measures should be conducted to assess the exposure risk, reduce the damage, and protect the consumers food safety

Numerical analysis of thermoelectric power generation coupled with temperature-dependent material properties

Thermoelectric generator (TEG) with improved performance is a promising technology in power supply and energy harvesting. Existing studies primarily adopt constant material properties to investigate TEG performance. However, thermoelectric (TE) material properties are subjected to considerable variations with temperature. Thus, reasonable doubts have risen concerning the influence level of temperature-dependent material properties on TEG performance. To solve this problem, an efficient and a comprehensive one-dimensional numerical model is developed to fully consider the third-order polynomial temperature-dependent thermal conductivity, Seebeck coefficient, and electrical resistivity. Control volume and finite difference algorithms are compared, and experiments are conducted to verify the developed numerical model. The temperature distribution along the TE leg obviously differs from the parabolic shape, which is a classic temperature distribution under the assumption of constant material properties. Insights find that the local change rate of thermal conductivity and Thomson effect are the essential reasons for the abovementioned phenomenon. It has been found that Thomson heat is released in the part of the leg near the cold-end, whereas it is absorbed in the remaining parts of the leg near the hot-end. The electric power on the basis of constant material properties is confirmed to be accurate enough by the developed numerical model, but the parabolic shape of the TE efficiency can be only obtained when temperature-dependent material properties are considered. Furthermore, it is wise to improve the TE efficiency by structural optimization. The present work provides an efficient and a comprehensive one-dimensional numerical model to include temperature-dependent material properties. New insights into the temperature and heat flux distribution, Thomson influence, and structural optimization potential are also presented for the in-depth understanding of the TE conversion process