ABSTRACT
Spintronics, a technology harnessing electron spin for information transmission, offers a promising avenue to surpass the limitations of conventional electronic devices. While the spin directly interacts with the magnetic field, its control through the electric field is generally more practical, and has become a focal point in the field. Here, we propose a mechanism to realize static and almost uniform effective magnetic field by gate-electric field. Our method employs two-dimensional altermagnets with valley-mediated spin-layer coupling (SLC), in which electronic states display valley-contrasted spin and layer polarization. For the low-energy valley electrons, a uniform gate field is approximately identical to a uniform magnetic field, leading to predictable control of spin. Through symmetry analysis and ab initio calculations, we predict altermagnetic monolayer Ca(CoN)_{2} and its family materials as potential candidates hosting SLC. We show that an almost uniform magnetic field (B_{z}) indeed is generated by gate field (E_{z}) in Ca(CoN)_{2} with B_{z}âE_{z} in a wide range, and B_{z} reaches as high as about 10^{3} T when E_{z}=0.2 eV/Å. Furthermore, owing to the clean band structure and SLC, one can achieve perfect and switchable spin and valley currents and significant tunneling magnetoresistance in Ca(CoN)_{2} solely using the gate field. Our work provides new opportunities to generate predictable control of spin and design spintronic devices that can be controlled by purely electric means.
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Cadmium (Cd) is readily absorbed by tobacco and accumulates in the human body through smoke inhalation, posing threat to human health. While there have been many studies on the negative impact of cadmium in tobacco on human health, the specific adaptive mechanism of tobacco roots to cadmium stress is not well understood. In order to comprehensively investigate the effects of Cd stress on the root system of tobacco, the combination of transcriptomic, biochemical, and physiological methods was utilized. In this study, tobacco growth was significantly inhibited by 50 µM of Cd, which was mainly attributed to the destruction of root cellular structure. By comparing the transcriptome between CK and Cd treatment, there were 3232 up-regulated deferentially expressed genes (DEGs) and 3278 down-regulated DEGs. The obvious differential expression of genes related to the nitrogen metabolism, metal transporters and the transcription factors families. In order to mitigate the harmful effects of Cd, the root system enhances Cd accumulation in the cell wall, thereby reducing the Cd content in the cytoplasm. This result may be mediated by plant hormones and transcription factor (TF). Correlational statistical analysis revealed significant negative correlations between IAA and GA with cadmium accumulation, indicated by correlation coefficients of -0.91 and -0.93, respectively. Conversely, ABA exhibited a positive correlation with a coefficient of 0.96. In addition, it was anticipated that 3 WRKY TFs would lead to a reduction in Cd accumulation. Our research provides a theoretical basis for the systematic study of the specific physiological processes of plant roots under Cd stress.
Subject(s)
Cadmium , Plant Growth Regulators , Transcription Factors , Transcriptome , Cadmium/toxicity , Cadmium/metabolism , Transcription Factors/metabolism , Transcription Factors/genetics , Transcriptome/drug effects , Plant Growth Regulators/metabolism , Nicotiana/genetics , Nicotiana/drug effects , Stress, Physiological , Plant Roots/drug effects , Plant Roots/metabolism , Gene Expression Regulation, Plant/drug effectsABSTRACT
Terrestrial ecosystem respiration increases exponentially with temperature, constituting a positive feedback loop accelerating global warming. However, the response of ecosystem respiration to temperature strongly depends on water availability, yet where and when the water effects are important, is presently poorly constrained, introducing uncertainties in climate-carbon cycle feedback projections. Here, we disentangle the effects of temperature and precipitation (a proxy for water availability) on ecosystem respiration by analysing eddy covariance CO2 flux measurements across 212 globally distributed sites. We reveal a threshold precipitation function, determined by the balance between precipitation and ecosystem water demand, which separates temperature-limited and water-limited respiration. Respiration is temperature limited for precipitation above that threshold function, whereas in drier areas water limitation reduces the temperature sensitivity of respiration and its positive feedback to global warming. If the trend of expansion of water-limited areas with warming climate over the last decades continues, the positive feedback of ecosystem respiration is likely to be weakened and counteracted by the increasing water limitation.
ABSTRACT
Background and Objective: Chronic atrophic gastritis (CAG) is a complex chronic disease caused by multiple factors that frequently occurs disease in the clinic. The worldwide prevalence of CAG is high. Interestingly, clinical CAG patients often present with a variety of symptom phenotypes, which makes it more difficult for clinicians to treat. Therefore, there is an urgent need to improve our understanding of the complexity of the clinical CAG population, obtain more accurate disease subtypes, and explore the relationship between clinical symptoms and medication. Therefore, based on the integrated platform of complex networks and clinical research, we classified the collected patients with CAG according to their different clinical characteristics and conducted correlation analysis on the classification results to identify more accurate disease subtypes to aid in personalized clinical treatment. Method: Traditional Chinese medicine (TCM) offers an empirical understanding of the clinical subtypes of complicated disorders since TCM therapy is tailored to the patient's symptom profile. We gathered 6,253 TCM clinical electronic medical records (EMRs) from CAG patients and manually annotated, extracted, and preprocessed the data. A shared symptom-patient similarity network (PSN) was created. CAG patient subgroups were established, and their clinical features were determined through enrichment analysis employing community identification methods. Different clinical features of relevant subgroups were correlated based on effectiveness to identify symptom-botanical botanical drugs correspondence. Moreover, network pharmacology was employed to identify possible biological relationships between screened symptoms and medications and to identify various clinical and molecular aspects of the key subtypes using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Results: 5,132 patients were included in the study: 2,699 males (52.60%) and 2,433 females (47.41%). The population was divided into 176 modules. We selected the first 3 modules (M29, M3, and M0) to illustrate the characteristic phenotypes and genotypes of CAG disease subtypes. The M29 subgroup was characterized by gastric fullness disease and internal syndrome of turbidity and poison. The M3 subgroup was characterized by epigastric pain and disharmony between the liver and stomach. The M0 subgroup was characterized by epigastric pain and dampness-heat syndrome. In symptom analysis, The top symptoms for symptom improvement in all three subgroups were stomach pain, bloating, insomnia, poor appetite, and heartburn. However, the three groups were different. The M29 subgroup was more likely to have stomach distention, anorexia, and palpitations. Citrus medica, Solanum nigrum, Jiangcan, Shan ci mushrooms, and Dillon were the most popular botanical drugs. The M3 subgroup has a higher incidence of yellow urine, a bitter tongue, and stomachaches. Smilax glabra, Cyperus rotundus, Angelica sinensis, Conioselinum anthriscoides, and Paeonia lactiflora were the botanical drugs used. Vomiting, nausea, stomach pain, and appetite loss are common in the M0 subgroup. The primary medications are Scutellaria baicalensis, Smilax glabra, Picrorhiza kurroa, Lilium lancifolium, and Artemisia scoparia. Through GO and KEGG pathway analysis, We found that in the M29 subgroup, Citrus medica, Solanum nigrum, Jiangcan, Shan ci mushrooms, and Dillon may exert their therapeutic effects on the symptoms of gastric distension, anorexia, and palpitations by modulating apoptosis and NF-κB signaling pathways. In the M3 subgroup, Smilax glabra, Cyperus rotundus, Angelica sinensis, Conioselinum anthriscoides, and Paeonia lactiflora may be treated by NF-κB and JAK-STAT signaling pathway for the treatment of stomach pain, bitter mouth, and yellow urine. In the M0 subgroup, Scutellaria baicalensis, Smilax glabra, Picrorhiza kurroa, Lilium lancifolium, and Artemisia scoparia may exert their therapeutic effects on poor appetite, stomach pain, vomiting, and nausea through the PI3K-Akt signaling pathway. Conclusion: Based on PSN identification and community detection analysis, CAG population division can provide useful recommendations for clinical CAG treatment. This method is useful for CAG illness classification and genotyping investigations and can be used for other complicated chronic diseases.
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The rapid development of neuromorphic computing has led to widespread investigation of artificial synapses. These synapses can perform parallel in-memory computing functions while transmitting signals, enabling low-energy and fast artificial intelligence. Robots are the most ideal endpoint for the application of artificial intelligence. In the human nervous system, there are different types of synapses for sensory input, allowing for signal preprocessing at the receiving end. Therefore, the development of anthropomorphic intelligent robots requires not only an artificial intelligence system as the brain but also the combination of multimodal artificial synapses for multisensory sensing, including visual, tactile, olfactory, auditory, and taste. This article reviews the working mechanisms of artificial synapses with different stimulation and response modalities, and presents their use in various neuromorphic tasks. We aim to provide researchers in this frontier field with a comprehensive understanding of multimodal artificial synapses.
ABSTRACT
Alveolar bone defect repair remains a persistent clinical challenge for periodontitis treatment. The use of peripheral functional seed cells is a hot topic in periodontitis. Herein, we explored the cellular behaviors and osteogenic ability of adipose-derived mesenchymal stem cells (ADSCs) treated with black phosphorus quantum dots (BPQDs). Additionally, macrophage polarization, osteogenic effects and angiogenesis were investigated through the paracrine pathway regulated by BPQD-modified ADSCs. Our results demonstrated that BPQDs showed good biocompatibility with ADSCs and BPQD-modified ADSCs could improve the bone repair in vivo inflammatory microenvironment by regulating osteogenesis and osteoimmunomodulation. The BPQDs increased the osteogenic differentiation of ADSCs via the Wnt/ß-catenin and BMP2/SMAD5/Runx2 signaling pathway. In addition, BPQD-modified ADSCs promoted the osteogenic effect of BMSCs and facilitated the polarization of macrophages from M1 towards M2 phenotype transformation through the paracrine pathway in the periodontitis microenvironment. This strategy provides a novel idea for treatment of alveolar bone defects for periodontitis in the foreseeable future.
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This paper considers estimating functional-coefficient models in panel quantile regression with individual effects, allowing the cross-sectional and temporal dependence for large panel observations. A latent group structure is imposed on the heterogenous quantile regression models so that the number of nonparametric functional coefficients to be estimated can be reduced considerably. With the preliminary local linear quantile estimates of the subject-specific functional coefficients, a classic agglomerative clustering algorithm is used to estimate the unknown group structure and an easy-to-implement ratio criterion is proposed to determine the group number. The estimated group number and structure are shown to be consistent. Furthermore, a post-grouping local linear smoothing method is introduced to estimate the group-specific functional coefficients, and the relevant asymptotic normal distribution theory is derived with a normalisation rate comparable to that in the literature. The developed methodologies and theory are verified through a simulation study and showcased with an application to house price data from UK local authority districts, which reveals different homogeneity structures at different quantile levels.
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Vascularization plays a significant role in promoting the expedited process of bone regeneration while also enhancing the stability and viability of artificial bone implants. Although titanium alloy scaffolds were designed to mimic the porous structure of human bone tissues to facilitate vascularization in bone repair, their biological inertness restricted their broader utilization. The unique attribute of Metal-organic framework (MOF) MIL-53(Fe), known as "breathing", can facilitate the efficient adsorption of extracellular matrix proteins and thus provide the possibility for efficient interaction between scaffolds and cell adhesion molecules, which helps improve the bioactivity of the titanium alloy scaffolds. In this study, MIL-53(Fe) was synthesized in situ on the scaffold after hydrothermal treatment. The MIL-53(Fe) endowed the scaffold with superior protein absorption ability and preferable biocompatibility. The scaffolds have been shown to possess favorable osteogenesis and angiogenesis inducibility. It was indicated that MIL-53(Fe) modulated the mechanotransduction process of endothelial cells and induced increased cell stiffness by promoting the adsorption of adhesion-mediating extracellular matrix proteins to the scaffold, such as laminin, fibronectin, and perlecan et al., which contributed to the activation of the endothelial tip cell phenotype at sprouting angiogenesis. Therefore, this study effectively leveraged the intrinsic "breathing" properties of MIL-53 (Fe) to enhance the interaction between titanium alloy scaffolds and vascular endothelial cells, thereby facilitating the vascularization inducibility of the scaffold, particularly during the sprouting angiogenesis phase. This study indicates that MIL-53(Fe) coating represents a promising strategy to facilitate accelerated and sufficient vascularization and uncovers the scaffold-vessel interaction from a biomechanical perspective.
Subject(s)
Neovascularization, Physiologic , Tissue Scaffolds , Titanium , Titanium/chemistry , Humans , Tissue Scaffolds/chemistry , Neovascularization, Physiologic/drug effects , Endothelial Cells/drug effects , Metal-Organic Frameworks/chemistry , Metal-Organic Frameworks/pharmacology , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Osteogenesis/drug effects , Alloys/chemistry , Human Umbilical Vein Endothelial Cells , Prostheses and Implants , Mechanotransduction, Cellular , Cell Adhesion/drug effects , Tissue Engineering/methodsABSTRACT
The abuse or misuse of antibiotics in clinical and agricultural settings severely endangers human health and ecosystems, which has raised profound concerns for public health worldwide. Trace detection and reliable discrimination of commonly used fluoroquinolone (FQ) antibiotics and their analogues have consequently become urgent to guide the rational use of antibiotic medicines and deliver efficient treatments for associated diseases. Herein, we report a wearable eye patch integrated with a quadruplex nanosensor chip for noninvasive detection and discrimination of primary FQ antibiotics in tears during routine eyedrop treatment. A set of dual-mode fluorescent nanoprobes of red- or green-emitting CdTe quantum dots integrated with lanthanide ions and a sensitizer, adenosine monophosphate, were constructed to provide an enhanced fluorescence up to 45-fold and nanomolar sensitivity toward major FQs owing to the aggregation-regulated antenna effect. The aggregation-driven, CdTe-Ln(III)-based microfluidic sensor chip is highly specific to FQ antibiotics against other non-FQ counterparts or biomolecular interfering species and is able to accurately discriminate nine types of FQ or non-FQ eyedrop suspensions using linear discriminant analysis. The prototyped wearable sensing detector has proven to be biocompatible and nontoxic to human tissues, which integrates the entire optical imaging modules into a miniaturized, smartphone-based platform for field use and reduces the overall assay time to â¼5 min. The practicability of the wearable eye patch was demonstrated through accurate quantification of antibiotics in a bactericidal event and the continuous profiling of FQ residues in tears after using a typical prescription antibiotic eyedrop. This technology provides a useful supplement to the toolbox for on-site and real-time examination and regulation of inappropriate daily drug use that might potentially lead to long-term antibiotic abuse and has great implications in advancing personal healthcare techniques for the regulation of daily medication therapy.
Subject(s)
Anti-Bacterial Agents , Fluoroquinolones , Quantum Dots , Tears , Wearable Electronic Devices , Humans , Anti-Bacterial Agents/analysis , Tears/chemistry , Tears/drug effects , Fluoroquinolones/analysis , Quantum Dots/chemistry , Tellurium/chemistry , Cadmium Compounds/chemistry , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Fluorescent Dyes/chemistry , Biosensing Techniques , Lab-On-A-Chip DevicesABSTRACT
Background: SLC30A5, a member of the solute transporter protein family, is implicated in tumorigenesis and cancer progression. This study aimed to explore the expression and prognostic significance of SLC30A family genes in pan-cancer, with a specific emphasis on SLC30A5 in hepatocellular carcinoma (HCC). Methods: Expression patterns and prognostic implications of SLC30A family genes were assessed across 33 cancer types, especially HCC. Co-expression analysis explored the relationship between SLC30A5 and immune cell infiltration, immune checkpoints, pathway molecules related to tumor angiogenesis and epithelial-mesenchymal transition (EMT). The role of SLC30A5 in HCC was evaluated through in vitro and in vivo assays, including CCK8 viability assay, EdU cell proliferation assay, colony formation assay, apoptosis assay, wound healing assay, transwell migration assay, and xenograft mouse model assay using Huh7 cells with targeted knockdown of SLC30A5. Results: SLC30A family genes exhibited overexpression in various tumors. In HCC, upregulation of SLC30A5 expression correlated with adverse prognosis. Significant associations were observed between SLC30A5 expression and immune cell infiltration, immune checkpoints, molecules involved in angiogenesis, and EMT. SLC30A5 overexpression was associated with advanced disease stages, higher histological grades, and vascular invasion. Single-cell RNA sequencing data (GSE112271) revealed notable SLC30A5 expression in malignant cells. In vitro and in vivo assays demonstrated that SLC30A5 knockdown in Huh7 cells reduced proliferation, migration, and invasion while promoting apoptosis. Conclusions: This study highlights the clinical relevance of SLC30A5 in HCC, emphasizing its role in cell proliferation and migration. SLC30A5 emerges as a promising candidate for a prognostic marker and a potential target in HCC.
ABSTRACT
Silicon (Si) can significantly improve the salt tolerance of plants, but its mechanism remains unclear. In this study, role of abscisic acid (ABA) in Si derived salt resistance in tobacco seedling was investigated. Under salt stress, the photosynthetic rate, stomatal conductance, and transpiration rate of tobacco seedlings were reduced by 86.17%, 80.63%, and 67.54% respectively, resulting in a decrease in biomass. The application of Si found to mitigate these stress-induced markers. However, positive role of Si was mainly attributed to the enhanced expression of aquaporin genes, which helped in enhancing root hydraulic conductance (Lpr) and ultimately maintaining the leaf relative water content (RWC). Moreover, sodium tungstate, an ABA biosynthesis inhibitor, was used to test the role of ABA on Si-regulating Lpr. The results indicated that the improvement of Lpr by Si was diminished in the presence of ABA inhibitor. In addition, it was observed that the ABA content was increased due to the Si-upregulated of ABA biosynthesis genes, namely NtNCED1 and NtNCED5. Conversely, the expression of ABA metabolism gene NtCYP7O7A was found to be reduced by Si. Together, this study suggested that Si increased ABA content, leading to enhanced efficiency of water uptake by the roots, ultimately facilitating an adequate water supply to maintain leaf water balance. As a result, there was an improvement in salt resistance in tobacco seedling.
ABSTRACT
BACKGROUND: In developing countries, including China, solid-fuel-based heating and cooking is common. For older people, the multimorbidity prevalence is exceptionally high. Nevertheless, studies on the associations of indoor solid fuels use, especially switching fuels types, on multimorbidity in middle-aged and older people is scarce. METHODS: Data from five waves of the China Health and Retirement Longitudinal Study were used in this study. Indoor fuels were classified as solid or clean fuels. Physical-psychological-cognitive multimorbidity (PPC-multimorbidity) was defined as the simultaneous presence of three disease types (physical illness, psychological disorders, cognitive impairment). Using Cox proportional risk models, hazard ratios (HRs) and 95â¯% confidence intervals (95â¯% CI) were calculated to investigate the associations of heating- and cooking-related baseline indoor fuels and switching indoor fuels with PPC-multimorbidity incidence. RESULTS: In the heating (n=3121, mean age=56.55 years, male proportion=54.25â¯%) and cooking (n=3574, mean age=56.67 years, male proportion=52.94â¯%) analyses, 75.07â¯% and 45.64â¯% of the participants used solid fuels at baseline, and 564 (18.07â¯%) and 613 (17.15â¯%) PPC-multimorbidity cases were diagnosed during follow-up, respectively. Participants with baseline heating- and cooking-based solid fuels use had greater PPC-multimorbidity incidences [HRs (95â¯% CIs): 1.23 (0.98, 1.55) and 1.44 (1.21, 1.73)], respectively. Additionally, combined baseline heating- and cooking-based solid fuels use was associated with even greater PPC-multimorbidity incidence [HR (95â¯% CI): 1.55 (1.18, 2.04)]. Persistent solid fuels use obviously increased the PPC-multimorbidity incidence [HRs (95â¯% CIs): 2.43 (1.67, 3.55) for heating and 2.63 (2.03, 3.40) for cooking]. Moreover, switching from solid to clean fuels was associated with a significantly decreased PPC-multimorbidity incidence [HRs (95â¯% CIs): 0.27 (0.20, 0.35) for heating and 0.36 (0.28, 0.46) for cooking]. CONCLUSIONS: Long-term solid-fuels use is associated with an increased PPC-multimorbidity incidence, and switching to cleaner fuels is associated with a decreased PPC-multimorbidity incidence in adults aged ≥45 years.
Subject(s)
Air Pollution, Indoor , Cooking , Heating , Multimorbidity , Humans , Male , Prospective Studies , China/epidemiology , Air Pollution, Indoor/statistics & numerical data , Female , Middle Aged , Incidence , Aged , Longitudinal Studies , Mental Disorders/epidemiologyABSTRACT
Microbial fuel cells (MFCs) have the dual advantage of mitigating Cr(â ¥) wastewater ecological threats while generating electricity. However, the low electron transfer efficiency and the limited enrichment of active electrogens are barriers to MFCs advancement. This study describes the synthesis of the TP-PDA-RGO@CC negative electrode using tea polyphenol as a reducing agent and polydopamine-doped graphene, significantly enhances the roughness and hydrophilicity of the anode. The charge transfer resistance was reduced by 94%, and the peak MFC power was 1375.80 mW m-2. Under acidic conditions, the Cr(â ¥) reduction rate reached 92% within 24 h, with a 52% increase in coulombic efficiency. Biodiversity analysis shows that the TP-PDA-RGO@CC anode could enrich electrogens, thereby boosting the electron generation mechanism at the anode and enhancing the reduction efficiency of Cr(â ¥) in the cathode chamber. This work emphasizes high-performance anode materials for efficient pollutant removal, energy conversion, and biomass reuse.
Subject(s)
Bioelectric Energy Sources , Chromium , Electrodes , Graphite , Indoles , Polymers , Polyphenols , Tea , Polyphenols/chemistry , Polymers/chemistry , Indoles/chemistry , Chromium/chemistry , Graphite/chemistry , Tea/chemistry , Wastewater/chemistry , Water Pollutants, Chemical/chemistry , Oxidation-ReductionABSTRACT
The rapid rise of antibiotic resistance and slow discovery of new antibiotics have threatened global health. While novel phage lysins have emerged as potential antibacterial agents, experimental screening methods for novel lysins pose significant challenges due to the enormous workload. Here, the first unified software package, namely DeepLysin, is developed to employ artificial intelligence for mining the vast genome reservoirs ("dark matter") for novel antibacterial phage lysins. Putative lysins are computationally screened from uncharacterized Staphylococcus aureus phages and 17 novel lysins are randomly selected for experimental validation. Seven candidates exhibit excellent in vitro antibacterial activity, with LLysSA9 exceeding that of the best-in-class alternative. The efficacy of LLysSA9 is further demonstrated in mouse bloodstream and wound infection models. Therefore, this study demonstrates the potential of integrating computational and experimental approaches to expedite the discovery of new antibacterial proteins for combating increasing antimicrobial resistance.
ABSTRACT
Enhancing the stability of multienzyme cascade reactions in metal-organic frameworks (MOFs) is a challenging task in the fields of biotechnology and chemistry. However, addressing this challenge could yield far-reaching benefits across the application range in the biomedical, food, and environmental sectors. In this study, multienzyme partitioning immobilization that sequentially immobilizes cascade enzymes with hierarchical MOFs is proposed to reduce substrate diffusion resistance. Conversion results of ginsenosides indicate that this strategy improves the cascade efficiency up to 1.26 times. The substrate diffusion model is used to investigate the dual-interenzyme mass transfer behavior of substrates in the restricted domain space and evaluate the substrate channeling effect under partitioning immobilization. Molecular docking and kinetic simulations reveal that the MOFs effectively limit the conformational changes of cascade enzymes at high temperatures and in organic solvents while maintaining a large pocket of active centers. This phenomenon increased efficient substrate docking to the enzyme molecules, further optimizing cascade efficiency. The results of the immobilization of GOX and horseradish peroxidase as model enzymes indicate that the partitioned MOF immobilization strategy could be used for universal adaptation of cascade enzymes.
Subject(s)
Enzymes, Immobilized , Horseradish Peroxidase , Metal-Organic Frameworks , Molecular Docking Simulation , Metal-Organic Frameworks/chemistry , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Horseradish Peroxidase/chemistry , Horseradish Peroxidase/metabolism , Kinetics , Ginsenosides/chemistry , Ginsenosides/metabolism , Enzyme StabilityABSTRACT
Cadmium (Cd), which accumulates in tobacco leaves, enters the human body through inhalation of smoke, causing harmful effects on health. Therefore, identifying the pivotal factors that govern the absorption and resistance of Cd in tobacco is crucial for mitigating the harmful impact of Cd. In the present study, four different Cd-sensitive varieties, namely, ZhongChuan208 (ZC) with resistance, ZhongYan100 (ZY), K326 with moderate resistance, and YunYan87 (YY) with sensitivity, were cultivated in hydroponic with different Cd concentrations (20⯵M, 40⯵M, 60⯵M and 80⯵M). The results indicated that plant growth was significantly decreased by Cd. Irrespective of the Cd concentration, ZC exhibited the highest biomass, while YY had the lowest biomass; ZY and K326 showed intermediate levels. Enzymatic (APX, CAT, POD) and nonenzymatic antioxidant (Pro, GSH) systems showed notable variations among varieties. The multifactor analysis suggested that the ZC and ZY varieties, with higher levels of Pro and GSH content, contribute to a decrease in the levels of MDA and ROS. Among all the Cd concentrations, ZC exhibited the lowest Cd accumulation, while YY showed the highest. Additionally, there were significant differences observed in Cd distribution and translocation factors among the four different varieties. In terms of Cd distribution, cell wall Cd accounted for the highest proportion of total Cd, and organelles had the lowest proportion. Among the varieties, ZC showed lower Cd levels in the cell wall, soluble fraction, and organelles. Conversely, YY exhibited the highest Cd accumulation in all tissues; K326 and ZY had intermediate levels. Translocation factors (TF) varied among the varieties under Cd stress, with ZC and ZY showing lower TF compared to YY and K326. This phenomenon mainly attributed to regulation of the NtNramp3 and NtNramp5 genes, which are responsible for the absorption and transport of Cd. This study provides a theoretical foundation for the selection and breeding of tobacco varieties that are resistant to or accumulate less Cd.
Subject(s)
Nicotiana , Nicotiana/chemistry , Nicotiana/genetics , Nicotiana/growth & development , Nicotiana/metabolism , Cadmium/toxicity , Drug Resistance , Gene Expression Regulation, Plant/drug effects , Stress, Physiological/drug effects , Antioxidants/metabolism , Cation Transport Proteins/metabolismABSTRACT
Numerous studies shown that silicon (Si) enhanced plants' resistance to cadmium (Cd). Most studies primarily focused on investigating the impact of Si on Cd accumulation. However, there is a lack of how Si enhanced Cd resistance through regulation of water balance. The study demonstrated that Si had a greater impact on increasing fresh weight compared to dry weight under Cd stress. This effect was mainly attributed to Si enhanced plant relative water content (RWC). Plant water content depends on the dynamic balance of water loss and water uptake. Our findings revealed that Si increased transpiration rate and stomatal conductance, leading to higher water loss. This, in turn, negatively impacted water content. The increased water content caused by Si could ascribe to improve root water uptake. The Si treatment significantly increased root hydraulic conductance (Lpr) by 131 % under Cd stress. This enhancement was attributed to Si upregulation genes expression of NtPIP1;1, NtPIP1;2, NtPIP1;3, and NtPIP2;1. Through meticulously designed scientific experiments, this study showed that Si enhanced AQP activity, leading to increased water content that diluted Cd concentration and ultimately improved plant Cd resistance. These findings offered fresh insights into the role of Si in bolstering plant resistance to Cd.
Subject(s)
Aquaporins , Cadmium , Nicotiana , Plant Roots , Seedlings , Silicon , Water , Cadmium/toxicity , Silicon/pharmacology , Silicon/chemistry , Plant Roots/metabolism , Plant Roots/drug effects , Seedlings/drug effects , Seedlings/metabolism , Nicotiana/drug effects , Nicotiana/metabolism , Aquaporins/metabolism , Water/chemistry , Plant Proteins/metabolism , Gene Expression Regulation, Plant/drug effects , Plant Transpiration/drug effectsABSTRACT
This paper studies the projection test for high-dimensional mean vectors via optimal projection. The idea of projection test is to project high-dimensional data onto a space of low dimension such that traditional methods can be applied. We first propose a new estimation for the optimal projection direction by solving a constrained and regularized quadratic programming. Then two tests are constructed using the estimated optimal projection direction. The first one is based on a data-splitting procedure, which achieves an exact t-test under normality assumption. To mitigate the power loss due to data-splitting, we further propose an online framework, which iteratively updates the estimation of projection direction when new observations arrive. We show that this online-style projection test asymptotically converges to the standard normal distribution. Various simulation studies as well as a real data example show that the proposed online-style projection test retains the type I error rate well and is more powerful than other existing tests.
ABSTRACT
To test independence between two high-dimensional random vectors, we propose three tests based on the rank-based indices derived from Hoeffding's D, Blum-Kiefer-Rosenblatt's R and Bergsma-Dassios-Yanagimoto's τ*. Under the null hypothesis of independence, we show that the distributions of the proposed test statistics converge to normal ones if the dimensions diverge arbitrarily with the sample size. We further derive an explicit rate of convergence. Thanks to the monotone transformation-invariant property, these distribution-free tests can be readily used to generally distributed random vectors including heavily tailed ones. We further study the local power of the proposed tests and compare their relative efficiencies with two classic distance covariance/correlation based tests in high dimensional settings. We establish explicit relationships between D,R,τ* and Pearson's correlation for bivariate normal random variables. The relationships serve as a basis for power comparison. Our theoretical results show that under a Gaussian equicorrelation alternative, (i) the proposed tests are superior to the two classic distance covariance/correlation based tests if the components of random vectors have very different scales; (ii) the asymptotic efficiency of the proposed tests based on D,τ* and R are sorted in a descending order.
ABSTRACT
Retinal degeneration, a leading cause of irreversible low vision and blindness globally, can be partially addressed by retina prostheses which stimulate remaining neurons in the retina. However, existing electrode-based treatments are invasive, posing substantial risks to patients and healthcare providers. Here, we introduce a completely noninvasive ultrasonic retina prosthesis, featuring a customized ultrasound two-dimensional array which allows for simultaneous imaging and stimulation. With synchronous three-dimensional imaging guidance and auto-alignment technology, ultrasonic retina prosthesis can generate programmed ultrasound waves to dynamically and precisely form arbitrary wave patterns on the retina. Neuron responses in the brain's visual center mirrored these patterns, evidencing successful artificial vision creation, which was further corroborated in behavior experiments. Quantitative analysis of the spatial-temporal resolution and field of view demonstrated advanced performance of ultrasonic retina prosthesis and elucidated the biophysical mechanism of retinal stimulation. As a noninvasive blindness prosthesis, ultrasonic retina prosthesis could lead to a more effective, widely acceptable treatment for blind patients. Its real-time imaging-guided stimulation strategy with a single ultrasound array, could also benefit ultrasound neurostimulation in other diseases.