The aim of the study was to explore the coping strategy and the effects of self‐efficacy of Chinese undergraduate nursing students when they face the stress in clinical practice. Convenience sampling ...was used to recruit undergraduate nursing students in Mainland China who have practiced 3 months in hospitals in their final college year. Self‐report questionnaires including demographics, Perceived Stress Scale, coping behaviour inventory and Generalized Self‐Efficacy Scale were collected. The results showed that during clinical practice, assignments and workload were the most common stress to students; transference was the most frequently used coping strategy by students. Self‐efficacy not only had a positive main effect in predicting the frequency of use of staying optimistic and problem solving strategies but also moderated the effects of stress from taking care of patients on transference strategy, as well as stress from assignments and workload on problem solving strategy. It is essential to bolster the students' self‐efficacy to reduce stress and adopt positively the coping strategies during clinical practice.
Face recognition techniques have been developed significantly in recent years. However, recognizing faces with partial occlusion is still challenging for existing face recognizers, which is heavily ...desired in real-world applications concerning surveillance and security. Although much research effort has been devoted to developing face de-occlusion methods, most of them can only work well under constrained conditions, such as all of faces are from a pre-defined closed set of subjects. In this paper, we propose a robust LSTM-Autoencoders (RLA) model to effectively restore partially occluded faces even in the wild. The RLA model consists of two LSTM components, which aims at occlusion-robust face encoding and recurrent occlusion removal respectively. The first one, named multi-scale spatial LSTM encoder, reads facial patches of various scales sequentially to output a latent representation, and occlusion-robustness is achieved owing to the fact that the influence of occlusion is only upon some of the patches. Receiving the representation learned by the encoder, the LSTM decoder with a dual channel architecture reconstructs the overall face and detects occlusion simultaneously, and by feat of LSTM, the decoder breaks down the task of face de-occlusion into restoring the occluded part step by step. Moreover, to minimize identify information loss and guarantee face recognition accuracy over recovered faces, we introduce an identity-preserving adversarial training scheme to further improve RLA. Extensive experiments on both synthetic and real data sets of faces with occlusion clearly demonstrate the effectiveness of our proposed RLA in removing different types of facial occlusion at various locations. The proposed method also provides significantly larger performance gain than other de-occlusion methods in promoting recognition performance over partially-occluded faces.
Arsenic (As) contamination in paddy soil can cause phytotoxicity and elevated As accumulation in rice grain. Rice varieties vary in As uptake and tolerance, but the underlying mechanisms remain ...unclear. In this study, the aus variety Kasalath was found to be more tolerant to arsenate As(V) than the japonica variety Nipponbare, but the two varieties showed similar arsenite As(III) tolerance. Nipponbare took up more phosphate (Pi) and As(V) than Kasalath. The expression of genes for Pi transporters or Pi homeostasis regulation was quantified. Nipponbare showed 2- to 3-fold higher expression of the Pi transporter genes OsPT2 and OsPT8 than Kasalath. Two ospt8 mutants were isolated from the Kasalath background and compared with an ospt8 mutant in the Nipponbare background. Mutation in OsPT8 in both backgrounds decreased As(V) uptake by 33–57%, increased As(V) tolerance assayed by root elongation by >100-fold, and abolished the varietal differences in As(V) uptake and tolerance. The results show that OsPT8 plays a key role in As(V) uptake and that As(V) uptake mediated by OsPT8 exerts a profound toxic effect on root elongation. The results also suggest that differential OsPT8 expression explains the varietal differences in As(V) uptake and tolerance between Kasalath and Nipponbare.
Rice is a major source of inorganic arsenic (iAs) in the human diet because paddy rice is efficient at accumulating As. Rice As speciation is dominated by iAs and dimethylarsinic acid (DMA). Here we ...review the global pattern in rice As speciation and the factors causing the variation. Rice produced in Asia shows a strong linear relationship between iAs and total As concentration with a slope of 0.78. Rice produced in Europe and the United States shows a more variable, but generally hyperbolic relationship with DMA being predominant in U.S. rice. Although there is significant genotypic variation in grain As speciation, the regional variations are primarily attributed to environmental factors. Emerging evidence also indicates that methylated As species in rice are derived from the soil, while rice plants lack the As methylation ability. Soil flooding and additions of organic matter increase microbial methylation of As, although the microbial community responsible for methylation is poorly understood. Compared with iAs, methylated As species are taken up by rice roots less efficiently but are transported to the grain much more efficiently, which may be an important factor responsible for the spikelet sterility disorder (straight-head disease) in rice. DMA is a weak carcinogen, but the level of ingestion from rice consumption is much lower than that of concern. Questions that require further investigations are identified.
Microbial arsenic (As) methylation and demethylation are important components of the As biogeochemical cycle. Arsenic methylation is enhanced under flooded conditions in paddy soils, producing mainly ...phytotoxic dimethylarsenate (DMAs) that can cause rice straighthead disease, a physiological disorder occurring widely in some rice growing regions. The key microbial groups responsible for As methylation and demethylation in paddy soils are unknown. Three paddy soils were incubated under flooded conditions. DMAs initially accumulated in the soil porewater, followed by a rapid disappearance coinciding with the production of methane. The soil from a rice straighthead disease paddy field produced a much larger amount of DMAs than the other two soils. Using metabolic inhibition, quantification of functional gene transcripts, microbial enrichment cultures and
C-labeled DMAs, we show that sulfate-reducing bacteria (SRB) and methanogenic archaea are involved in As methylation and demethylation, respectively, controlling the dynamics of DMAs in paddy soils. We present a model of As biogeochemical cycle in paddy soils, linking the dynamics of changing soil redox potential with arsenite mobilization, arsenite methylation and subsequent demethylation driven by different microbial groups. The model provides a basis for controlling DMAs accumulation and incidence of straighthead disease in rice.
Current definitions of essential or beneficial elements for plant growth rely on narrowly defined criteria that do not fully represent a new vision for plant nutrition and compromise fertilizer ...regulation and practice. A new definition of what is a plant nutrient that is founded in science and relevant in practice has the potential to revitalize innovation and discovery. A proposed new definition might read:
A mineral plant nutrient is an element which is essential or beneficial for plant growth and development or for the quality attributes of the plant or harvested product, of a given plant species, grown in its natural or cultivated environment. A plant nutrient may be considered essential if the life cycle of a diversity of plant species cannot be completed in the absence of the element. A plant nutrient may be considered beneficial if it does not meet the criteria of essentiality, but can be shown to benefit plant growth and development or the quality attributes of a plant or its harvested product
. It includes elements currently identified as essential, elements for which a clear plant metabolic function has been identified, as well as elements that have demonstrated clear benefits to plant productivity, crop quality, resource use efficiency, stress tolerance or pest and disease resistance. We propose an open scientific debate to refine and implement this updated definition of plant nutrients. Other outcomes of this debate could be a more precise definition of the experimental evidence required to classify an element as a plant nutrient, and an independent scientific body to regularly review the list of essential and beneficial nutrients. The debate could also attempt to refine the definition of plant nutrients to better align with nutrients deemed essential for animal and human nutrition, thus following a more holistic ’one nutrition‘ concept.
Cadmium (Cd) and arsenic (As) are loaded into rice grain via two pathways: i) root uptake from the soil and then translocation to the grain, and ii) remobilization of Cd and As previously accumulated ...within the vegetative tissues to the grain. However, the relative contributions of the two pathways are not well understood in soil-grown rice plants. In this study, we used eight different water management regimes applied at different growth periods to manipulate the concentrations of Cd and As in porewater and then established a mathematical model to estimate the relative importance of the two pathways. Different water management regimes had dramatic and opposite effects on the solubility of Cd and As in soil, and their subsequent accumulation in both straw and grain. Water management applied at different growth periods had markedly different impacts on grain Cd and As concentrations. Water management during grain filling had a much greater impact on grain Cd than on grain As concentrations, whereas water treatment during the vegetative growth stage had a larger effect on grain As concentrations. Under the typical water management practice (i.e. flooding through the vegetative stage followed by drainage during grain filling), grain filling is the key period for the accumulation of Cd in the grain, with 98% of the grain Cd from root uptake during this period and the contribution of remobilization being very limited. In contrast, 95% of the grain As was remobilized from that accumulated within the plant prior to the grain filling, with the tillering, jointing, and heading period each contributing 20–40% of the grain As, whereas root uptake during grain filling contributed minor. These differences can be harnessed to design a segmented water management strategy to control grain Cd and As accumulation simultaneously.
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•The contributions of root uptake and remobilization of Cd/As to rice grain were estimated.•98% of the grain Cd is from rice root uptake from porewater during grain filling.•95% of the grain As is the remobilization of As accumulated prior to grain filling.•Grain filling is the key period for grain Cd but the vegetative growth period is key for grain As.•A segmented water management can be tailored to control grain Cd and As simultaneously.
Copper (Cu) is an essential micronutrient for all living organisms but is also highly toxic in excess. Cellular homoeostasis of Cu is maintained by various transporters and metallochaperones. Here, ...we investigated the biological function of OsCOPT7, a member of the copper transporters (COPT) family, in Cu homoeostasis in rice. OsCOPT7 was mainly expressed in the roots and the expression was upregulated by Cu deficiency. OsCOPT7 was localized at the tonoplast and the endoplasmic reticulum. Knockout of OsCOPT7 increased Cu accumulation in the roots but decreased Cu concentrations in the shoots and grain. The knockout mutants contained higher concentrations of Cu in the roots cell sap but markedly lower concentrations of Cu in the xylem sap than wild‐type plants. Seed setting and grain yield were reduced significantly in the knockout mutants grown in a low Cu soil. Knockout mutants were more tolerant to Cu toxicity. Yeast two‐hybrid and bimolecular fluorescence complementation assays showed that OsCOPT7 interacts physically with the rice Cu chaperone antioxidant protein 1 (OsATX1). Taken together, our results indicate that OsCOPT7 is a specific Cu transporter functioning to export Cu from the vacuoles and the ER and plays an important role in controlling the root‐to‐shoot Cu translocation in rice.
Summary statement
Copper (Cu) is an essential micronutrient for all living organisms but is also highly toxic in excess. Cellular homoeostasis of Cu is maintained by various transporters and metallochaperones. We show that OsCOPT7 is a Cu transporter functioning to export Cu from the vacuoles and the endoplasmic reticulum and plays an important role in controlling the root‐to‐shoot Cu translocation in rice.
Agricultural soils are under threat of toxic metal/metalloid contamination from anthropogenic activities, leading to excessive accumulation of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) ...in food crops that poses significant risks to human health. Understanding how these toxic metals and their methylated species are taken up, translocated, and detoxified is prerequisite to developing strategies to limit their accumulation for safer food. Toxic metals are taken up and transported across different cellular compartments and plant tissues via various transporters for essential or beneficial nutrients, e.g. As by phosphate and silicon transporters, and Cd by manganese (Mn), zinc (Zn), and iron (Fe) transporters. These transport processes are subjected to interactions with nutrients and the regulation at the transcriptional and post-translational levels. Complexation with thiol-rich compounds, such as phytochelatins, and sequestration in the vacuoles are the common mechanisms for detoxification and for limiting their translocation. A number of genes involved in toxic metal uptake, transport, and detoxification have been identified, offering targets for genetic manipulation via gene editing or transgenic technologies. Natural variations in toxic metal accumulation exist within crop germplasm, and some of the quantitative trait loci underlying these variations have been cloned, paving the way for marker-assisted breeding of low metal accumulation crops. Using plants to extract and remove toxic metals from soil is also possible, but this phytoremediation approach requires metal hyperaccumulation for efficiency. Knowledge gaps and future research needs are also discussed.
Accumulation of toxic metals and metalloids, such as arsenic, cadmium, lead, and mercury in food crops, can affect food safety and human health. This review discusses the molecular mechanisms and regulation of their uptake, transport, and detoxification as well as crop improvement strategies to reduce their accumulation in the edible parts. The potential of using metal-accumulating plants to clean up contaminated soil is also discussed.
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