Epigenetic Landscape of Plants Zhang, Xiaoyu
Science (American Association for the Advancement of Science),
04/2008, Volume:
320, Issue:
5875
Journal Article
Peer reviewed
In plants, DNA methylation, histone modifications, and RNA interference play critically important roles in regulating chromatin structure, thereby profoundly affecting transcription and other ...molecular events. Recent advances in microarray and high-throughput sequencing technologies have enabled genome-wide studies of these pathways in great detail. The vast amounts of "epigenomic" data generated so far have provided new insights into the mechanisms and functions of these pathways and have broadened our understanding of the structure and organization of plant chromatin as a whole.
Patent classification is of great importance to effective patent analysis. Traditional manual classification suffers from the problem of low efficiency and high expense. To address this issue, an ...interactive patent classification algorithm based on multi-classifier fusion and active learning is proposed in this paper, which comprises the construction and update of classification model. For model construction, a sub-classifier is trained for each class of the patents by means of support vector machine. Via multi-classifier fusion, the sub-classifiers are effectively combined to acquire enhanced classifiers, based on which the classification decision can be made. For model update, active learning is used to select the most informative patents for labeling, in which dynamic batch sampling is presented to cope with the problem of redundancy in traditional batch mode. Using dynamic certainty propagation, the selected patents become more informative for active learning. By iterating model construction and update, the classification performance can be gradually refined. The interactive classification algorithm is applied to both synthetic data and patents, and its effectiveness is demonstrated by the encouraging results.
The slow hydrogen oxidation reaction (HOR) kinetics under alkaline conditions remain a critical challenge for the practical application of alkaline exchange membrane fuel cells. Herein, Ru/RuO2 ...in‐plane heterostructures are designed with abundant active Ru–RuO2 interface domains as efficient electrocatalysts for the HOR in alkaline media. The experimental and theoretical results demonstrate that interfacial Ru and RuO2 domains at Ru–RuO2 interfaces are the optimal H and OH adsorption sites, respectively, endowing the well‐defined Ru(100)/RuO2(200) interface as the preferential region for fast alkaline hydrogen electrocatalysis. More importantly, the metallic Ru domains become electron deficient due to the strong interaction with RuO2 domains and show substantially improved inoxidizability, which is vital to maintain durable HOR electrocatalytic activity. The optimal Ru/RuO2 heterostructured electrocatalyst exhibits impressive alkaline HOR activity with an exchange current density of 8.86 mA cm−2 and decent durability. The exceptional electrocatalytic performance of Ru/RuO2 in‐plane heterostructure can be attributed to the robust and multifunctional Ru–RuO2 interfaces endowed by the unique metal–metal oxide domains.
A Ru/RuO2 in‐plane heterostructure is designed as an efficient electrocatalyst toward the alkaline hydrogen oxidation reaction (HOR). The interfacial Ru and RuO2 domains are the optimal H and OH adsorption sites, respectively. The Ru domains are electron deficient and show substantially improved inoxidizability. The results highlight the significance of establishing robust and multifunctional heterointerfaces toward fast alkaline HOR and beyond.
Measurement of viscosity of crude oil is critical for reservoir simulators. Computational modeling is a useful tool for correlation of crude oil viscosity to reservoir conditions such as pressure, ...temperature, and fluid compositions. In this work, multiple distinct models are applied to the available dataset to predict heavy-oil viscosity as function of a variety of process parameters and oil properties. The computational techniques utilized in this work are Decision Tree (DT), MLP, and GRNN which were utilized in estimation of heavy crude oil samples collected from middle eastern oil fields. For the estimation of viscosity, the firefly algorithm (FA) was employed to optimize the hyper-parameters of the machine learning models. The RMSE error rates for the final models of DT, MLP, and GRNN are 40.52, 25.08, and 30.83, respectively. Also, the R2-scores are 0.921, 0. 978, and 0.933, respectively. Based on this and other criteria, MLP is chosen as the best model for this study in estimating the values of crude oil viscosity.
Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and ...regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges.
•A MET-based PBK model is proposed for exposure assessment at varying physical activity levels.•An Excel-based operational tool enables users to generate exposure levels related to MET.•Intensive ...physical activities reduce the potentials for chemical bioaccumulation in the human body.
Physical activity levels have the potential to impact human internal exposure to environmental chemicals. However, the current lack of simple modeling approaches hinders the high-throughput screening of chemical exposure at different physical activity levels. To address this gap, this study proposes a straightforward model for assessing human internal exposure to chemicals. Our approach is based on the physiologically based kinetic (PBK) model and utilizes the metabolic equivalent of task (MET) to characterize internal exposure to chemicals at varying activity levels. To facilitate the application of this model, we have developed an Excel-based operation tool, allowing users to easily modify the MET value and generate simulation results for different physical activity levels. The simulation results demonstrate that as physical activity levels increase, the biotransfer factors (BTFs) of chemicals decrease, suggesting that higher physical activity levels reduce the bioaccumulation potential of chemicals. The intensified physical activity enhances the overall elimination kinetics of chemicals from the human body. However, the simulated concentrations of chemicals in the human body increase with higher physical activity levels, due to the significantly increased external exposure to chemicals, such as through inhalation. Our proposed modeling approach, along with the operational tool, enables high-throughput simulation of human chronic internal exposure to chemicals at different physical activity levels, where the findings can assist in screening chemicals for further health risk assessment. To accomplish this, the model incorporates certain assumptions and utilizes generic model input values. However, due to the intricate nature of the interaction between external and internal exposures at different physical activity levels, validating the simulation through experimental studies becomes challenging and is not performed in this study. For future studies, we recommend incorporating more MET-related physiological input variables, improving energy balance estimates, comprehending external exposure estimates, and conducting cohort studies to enhance and validate the proposed modeling approach.
A method is proposed to improve the photo/electroluminescence efficiency and stability of CsPbI3 perovskite nanocrystals (NCs) by using SrCl2 as a co‐precursor. The SrCl2 is chosen as the dopant to ...synthesize the CsPbI3 NCs. Because the ion radius of Sr2+ (1.18 Å) is slightly smaller than that of Pb2+ (1.19 Å) ions, divalent Sr2+ cations can partly replace the Pb2+ ions in the lattice structure of perovskite NCs and cause a slight lattice contraction. At the same time, Cl− anions from SrCl2 are able to efficiently passivate surface defect states of CsPbI3 nanocrystals, thus converting nonradiative trap states to radiative states. The simultaneous Sr2+ ion doping and surface Cl− ion passivation result in the enhanced photoluminescence quantum yield (up to 84%), elongated emission lifetime, and improved stability. Sr2+‐doped CsPbI3 NCs are employed to produce light‐emitting devices with a high external quantum yield of 13.5%.
SrCl2 is introduced as a co‐precursor in the synthesis of CsPbI3 perovskite nanocrystals to realize their simultaneous Sr2+ cation doping and surface Cl− anion passivation. The stability of the nanocrystals is improved, and light‐emitting devices with a high external quantum efficiency of 13.5% are realized.
Pesticide application techniques are critical not only for integrated pest management (IPM) but also for food and environmental safety. Assessing pesticide application efficiency on plants can help ...optimize IPM and reduce pesticide environmental impacts. With hundreds of pesticides registered for use in agriculture, this study proposed a modeling approach based on plant uptake models for generalizing routes of plant chemical exposures that can correspond to different types of pesticide application methods and evaluating their respective efficiency on plants. Three representative pesticide application methods (i.e., drip irrigation, foliar spray, and broadcast application) were selected for modeling simulations. The simulation results for three representative pesticides (i.e., halofenozide, pymetrozine, and paraquat) revealed that the soil-based transpiration exposure route facilitated the bioaccumulation of moderately lipophilic compounds in leaves and fruits. While the plant surface-based exposure route (i.e., leaf cuticle penetration) made it easier for highly lipophilic compounds to enter plants, moderately lipophilic pesticides (i.e., log KOW ∼ 2) were more soluble in phloem sap, which enhanced their subsequent transport within plant tissues. In general, moderately lipophilic pesticides had the highest simulated residue concentrations in plant tissues for the three specific application methods, indicating they had the highest application efficiency due to their enhanced uptake routes (via transpiration and surface penetration) and increased solubility in xylem and phloem saps. Compared to foliar spray and broadcast application, drip irrigation produced higher residue concentrations for a wide variety of pesticides, exhibiting the highest application efficiency for many pesticides, especially for moderately lipophilic compounds. Future research should incorporate plant growth stages, crop safety, pesticide formulations, and multiple application events into the modeling approach for understanding pesticide application efficiency evaluation.
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•A modeling approach generalized routes of plant chemical exposure for evaluating pesticide application efficiency.•Drip irrigation, foliar spray, and broadcast application methods were selected for modeling simulations.•Moderately lipophilic pesticides (log KOW: 0 – 3) exhibited high pesticide application efficiency.•High pesticide application efficiency may indicate potential food safety concerns.
China is currently vigorously implementing the “energy conservation and emission reduction” and “dual carbon” strategies. As the most resource-advantaged light metal material in China, Magnesium (Mg) ...alloy is progressively expanding its application in automobile, rail transportation, aerospace, medical, and electronic products. Chongqing University, Shanghai Jiaotong University, and Australian National University have conducted extensive research on the preparation, properties, and processes of Mg alloys. In the past 20 years, the proportion of Mg alloy in the automotive industry has gradually expanded, whereas currently the design and development of Mg alloy parts for automobiles has rarely been reported. Thus, the application models and typical parts cases of Mg alloy are summarized mainly from the four systems of the whole vehicle (body system, chassis system, powertrain system, interior, and exterior system). Subsequently, two actual original equipment manufacturers (OEM) cases are used to introduce the development logic of reliable die-cast Mg alloy, including forward design, formability analysis, process design analysis, structural redesign, manufacturing, and testing, aiming to share the methods, processes, and focus of attention of automotive OEMs for developing Mg alloy parts to enhance the confidence and motivation of applying Mg alloy in automotive field. Eventually, the multiple challenges faced by Mg alloy materials are sorted out and how to face these challenges are discussed. National policies and regulations, environmental protection and energy saving, and consumer demand will continue to promote the application of Mg.
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•Intestinal oxidative stress depends on the balance of ROS.•The antioxidant defense system protects intestine from oxidative stress damage.•Phytochemicals with health effects could be ...developed to nutritional supplements.
Oxidative stress occurs when there exists an imbalance between the generation and elimination of reactive oxygen species (ROS). As inevitable exposure to foreign substances and microbial pathogens, intestine is a key resource of ROS. Disproportionate generation and long-term exposure to ROS lead to various intestinal diseases, such as inflammatory bowel diseases (IBD), enteric infections, ischemic intestinal injury and colorectal cancers. Natural nutrients including vitamins, proteins, fats, minerals and phytochemicals provide numerous evidences that they can protect the health of intestine and alleviate the damage caused by oxidative stress, which can be developed as novel functional foods. This review summarized the recent research progress on the insights of the causes, mechanisms of intestinal oxidative stress and the health intervention effects of nutrients. This review has also given the prospects that the new discovered nutrients with health benefits might be developed as novel functional foods or possible nutraceutical agents.
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