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Abstract Epigenetic modifications are crucial for plant development. EFD ( E xine F ormation D efect) encodes a SAM-dependent methyltransferase that is essential for the pollen wall pattern formation and male fertility in Arabidopsis. In this study, we find that the expression of DRM2, a de novo DNA methyltransferase in plants, complements for the defects in efd, suggesting its potential de novo DNA methyltransferase activity. Genetic analysis indicates that EFD functions through HB21, as the knockout of HB21 fully restores fertility in efd mutants. DNA methylation and histone modification analyses reveal that EFD represses the transcription of HB21 through epigenetic mechanisms. Additionally, we demonstrate that HB21 directly represses the expression of genes crucial for pollen formation and anther dehiscence, including CalS5, RPG1/SWEET8, CYP703A2 and NST2. Collectively, our findings unveil a double negative regulatory cascade mediated by epigenetic modifications that coordinates anther development, offering insights into the epigenetic regulation of this process.

The migration and redistribution of refrigerant are critical factors that affect the refrigeration system performance. To improve the defrosting and start-up heating performance, it is essential to investigate the transient distribution characteristics of refrigerant mass. However, quantitative studies on the transient distribution of refrigerant during defrosting and start-up heating stages in heat pump systems are scarce. The dynamic characteristics of defrosting and start-up heating cannot be deeply understood from the perspective of refrigerant migration. Therefore, the purpose of this paper is to experimentally study the transient distribution characteristics of refrigerants during defrosting and start-up heating stages for different defrosting strategies. Based on the refrigerant-side dynamic characteristics, the defrosting cycle is divided into three stages for the defrosting strategy with the indoor fan off, the indoor coil charging stage, accumulator charging stage, and wet compression stage. Additionally, for the defrosting strategy with the indoor fan on, it is divided into two stages: the indoor coil charging stage and the outdoor coil discharging stage. For the defrosting strategy with the indoor fan off, the wet compression phenomenon occurs at 240 s, which poses significant challenges to the stability of the compressor. At the end of defrosting, the accumulator retains the most refrigerant for both defrosting strategies. From the perspective of refrigerant transient distribution, the start-up heating stage is the process of refrigerant migration from the accumulator to indoor and outdoor coils. The two main factors that affect start-up heating performance are heating the indoor coil metal, and vaporizing the liquid refrigerant in the accumulator. For the defrosting strategy with indoor fan on, the energy consumption of heating the indoor coil and vaporizing the liquid refrigerant is reduced by 45.7 % and 48.9 % during start-up heating. Based on the transient refrigerant distribution experiment, some methods to improve defrosting and start-up heating are also proposed. This study can provide useful insights into the transient distribution of refrigerants and provide guidance for defrosting optimization.

In order to obtain mannanase-producing Lactobacillus acidophilus strain, the mannanase expression vector was constructed and transformed into L. acidophilus. The enzymatic properties of mannanase produced by recombinant L. acidophilus were analyzed, and the acid resistance of recombinant L. acidophilus and anti-protease activity of mannanase were determined. The results showed that the mannanase activity produced by recombinant L. acidophilus was 353 U/ml after fermentation for 24 h. The optimum catalytic pH and temperature of mannanase was 5.5 and 55 ℃, respectively. The recombinant L. acidophilus had certain acid resistance at pH 2.0 to 4.5, and the survival rate was 77.3% at pH 2.0 for 2 h. After mannanase solution was treated with pepsin and trypsin for 160 min, the relative activities of mannanase were 65% and 28%, respectively. The results indicated that the mannanase had certain anti-pepsin and partial anti-trypsin degradation ability.

For finned-tube heat exchangers, owing to the extremely different refrigerant pressure drop characteristics between condensation and evaporation processes, the optimum refrigerant circuits of these two conditions are different. However, for a typical heat pump type air conditioner, refrigerant circuit of the conventional heat exchanger (CHX) is fixed no matter what operation condition is conducted. To solve this problem, a modified variable-circuit heat exchanger (VCHX) is developed for air conditioner outdoor unit applications. The VCHX, for which the refrigerant circuit can be easily switched by using a globe valve, could provide better matching characteristics between refrigerant circuit and operation condition variations. With a developed simulation model, refrigerant circuit of the VCHX is optimized by using the entropy generation minimization theory. Then, comparative experimental works were conducted to investigate the performance of VCHX and CHX systems in detail. Experimental results show that the presented VCHX is more suitable for high heating capacity and low cooling capacity applications. Based on the Chinese APF (annual performance factor) Standard, the VCHX system yields 6.5% higher APF value over CHX system. Significantly, economic analysis indicates that the investment payback period of VCHX system is 1.46 year, which is much lower than the designed lifetime of a residential air conditioner. In general, the VCHX technique has a great application potential for improving the overall performance of a heat pump type air conditioner.

Background: Polygenic risk score (PRS) can evaluate the individual-level genetic risk of breast cancer. However, standalone single nucleotide polymorphisms (SNP) data used for PRS may not provide satisfactory prediction accuracy. Additionally, current PRS models based on linear regression have insufficient power to leverage non-linear effects from thousands of associated SNPs. Here, we proposed a transcriptional risk score (TRS) based on multiple omics data to estimate the risk of breast cancer. Methods: The multiple omics data and clinical data of breast invasive carcinoma (BRCA) were collected from the cancer genome atlas (TCGA) and the gene expression omnibus (GEO). First, we developed a novel TRS model for BRCA utilizing single omic data and LightGBM algorithm. Subsequently, we built a combination model of TRS derived from each omic data to further improve the prediction accuracy. Finally, we performed association analysis and prognosis prediction to evaluate the utility of the TRS generated by our method. Results: The proposed TRS model achieved better predictive performance than the linear models and other ML methods in single omic dataset. An independent validation dataset also verified the effectiveness of our model. Moreover, the combination of the TRS can efficiently strengthen prediction accuracy. The analysis of prevalence and the associations of the TRS with phenotypes including case-control and cancer stage indicated that the risk of breast cancer increases with the increases of TRS. The survival analysis also suggested that TRS for the cancer stage is an effective prognostic metric of breast cancer patients. Conclusions: Our proposed TRS model expanded the current definition of PRS from standalone SNP data to multiple omics data and outperformed the linear models, which may provide a powerful tool for diagnostic and prognostic prediction of breast cancer.

Abstract The potential role of DNA methylation from paracancerous tissues in cancer diagnosis has not been explored until now. In this study, we built classification models using well-known machine learning models based on DNA methylation profiles of paracancerous tissues. We evaluated our methods on nine cancer datasets collected from The Cancer Genome Atlas (TCGA) and utilized fivefold cross-validation to assess the performance of models. Additionally, we performed gene ontology (GO) enrichment analysis on the basis of the significant CpG sites selected by feature importance scores of XGBoost model, aiming to identify biological pathways involved in cancer progression. We also exploited the XGBoost algorithm to classify cancer types using DNA methylation profiles of paracancerous tissues in external validation datasets. Comparative experiments suggested that XGBoost achieved better predictive performance than the other four machine learning methods in predicting cancer stage. GO enrichment analysis revealed key pathways involved, highlighting the importance of paracancerous tissues in cancer progression. Furthermore, XGBoost model can accurately classify nine different cancers from TCGA, and the feature sets selected by XGBoost can also effectively predict seven cancer types on independent GEO datasets. This study provided new insights into cancer diagnosis from an epigenetic perspective and may facilitate the development of personalized diagnosis and treatment strategies.

Tin is one of the few rare metals with important strategic position in our country' but the technical limitations of the comprehensive utilization have led to the increasing scarcity of in ore resources' the large loss rate of useful components' and the increase in the amount of tailings over the years. Tailings not only occupy a lot of land' but also pollute the surrounding environment. Therefore, it has great significance of the green utilization of tin tailings resources to ensure the safety of tin mineral resources in China. In this paper, the current situation and characteristics of tin tailings resources at home and abroad was in reduced. It was summarized that it the key of secondary benefication of the in tailings is to solve the influence of sulfide minerals iron and manganese mineras and slime on comprehensive recovery of tine cassiterite and co-associated valuable components. Meanwhile, the technological characteristics and cases of tin tailings research status are also summarized. At present, the main methods to re-use tin tailings include recovery valuable metals by gravity separation, magnetic separation, flotation and combined beneficiation and metallurgy, used tailings as building materials or mining tailings as a whole, and treated waste stone containing tin as a special tailings to pre-concentrated. The common collectors and regulators of cassiterite flotation and their action mechanism were summarized. The researches which should be strengthen in the future were proposed, including enhancing the recovery of tine cassiterite, enhancing the new gravity separation equipment of cassiterite separation, enhancing the development of new green reagents, and enhancing development of new flotation equipment. The future development trend based on the research hot topic was proposed, with a view to providing reference for the green and efficient utilization of in tailings. [ABSTRACT FROM AUTHOR]