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1.
Neural Netw ; 175: 106307, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38626617

RESUMO

Weakly supervised temporal action localization aims to locate the temporal boundaries of action instances in untrimmed videos using video-level labels and assign them the corresponding action category. Generally, it is solved by a pipeline called "localization-by-classification", which finds the action instances by classifying video snippets. However, since this approach optimizes the video-level classification objective, the generated activation sequences often suffer interference from class-related scenes, resulting in a large number of false positives in the prediction results. Many existing works treat background as an independent category, forcing models to learn to distinguish background snippets. However, under weakly supervised conditions, the background information is fuzzy and uncertain, making this method extremely difficult. To alleviate the impact of false positives, we propose a new actionness-guided false positive suppression framework. Our method seeks to suppress false positive backgrounds without introducing the background category. Firstly, we propose a self-training actionness branch to learn class-agnostic actionness, which can minimize the interference of class-related scene information by ignoring the video labels. Secondly, we propose a false positive suppression module to mine false positive snippets and suppress them. Finally, we introduce the foreground enhancement module, which guides the model to learn the foreground with the help of the attention mechanism as well as class-agnostic actionness. We conduct extensive experiments on three benchmarks (THUMOS14, ActivityNet1.2, and ActivityNet1.3). The results demonstrate the effectiveness of our method in suppressing false positives and it achieves the state-of-the-art performance. Code: https://github.com/lizhilin-ustc/AFPS.

2.
J Ethnopharmacol ; 328: 118126, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38556140

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: The repairment of myelin sheaths is crucial for mitigating neurological impairments of intracerebral hemorrhage (ICH). However, the current research on remyelination processes in ICH remains limited. A representative traditional Chinese medicine, Buyang Huanwu decoction (BYHWD), shows a promising therapeutic strategy for ICH treatment. AIM OF THE STUDY: To investigate the pro-remyelination effects of BYHWD on ICH and explore the underlying mechanisms. MATERIALS AND METHODS: The collagenase-induced mice ICH model was created for investigation. BYHWD's protective effects were assessed by behavioral tests and histological staining. Transmission electron microscopy was used for displaying the structure of myelin sheaths. The remyelination and oligodendrocyte differentiation were evaluated by the expressions of myelin proteolipid protein (PLP), myelin basic protein (MBP), MBP/TAU, Olig2/CC1, and PDGFRα/proliferating cell nuclear antigen (PCNA) through RT-qPCR and immunofluorescence. Transcriptomics integrated with disease database analysis and experiments in vivo and in vitro revealed the microRNA-related underlying mechanisms. RESULTS: Here, we reported that BYHWD promoted the neurological function of ICH mice and improved remyelination by increasing PLP, MBP, and TAU, as well as restoring myelin structure. Besides, we showed that BYHWD promoted remyelination by boosting the differentiation of PDGFRα+ oligodendrocyte precursor cells into olig2+/CC1+ oligodendrocytes. Additionally, we demonstrated that the remyelination effects of BYHWD worked by inhibiting G protein-coupled receptor 17 (GPR17). miRNA sequencing integrated with miRNA database prediction screened potential miRNAs targeting GPR17. By applying immunofluorescence, RNA in situ hybridization and dual luciferase reporter gene assay, we confirmed that BYHWD suppressed GPR17 and improved remyelination by increasing miR-760-3p. CONCLUSIONS: BYHWD improves remyelination and neurological function in ICH mice by targeting miR-760-3p to inhibit GPR17. This study may shed light on the orchestration of remyelination mechanisms after ICH, thus providing novel insights for developing innovative prescriptions with brain-protective properties.


Assuntos
Medicamentos de Ervas Chinesas , MicroRNAs , Remielinização , Camundongos , Animais , Receptor alfa de Fator de Crescimento Derivado de Plaquetas , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Hemorragia Cerebral/tratamento farmacológico , Hemorragia Cerebral/metabolismo , Receptores Acoplados a Proteínas G/genética , MicroRNAs/genética , Proteínas do Tecido Nervoso
3.
Adv Sci (Weinh) ; : e2400094, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38400587

RESUMO

Numerous organic electrolytes additives have been reported to improve Zn anode performance in aqueous Zn metal batteries (AZMBs). However, the modification mechanism needs to be further revealed in consideration of different environments for electrolytes and electrodes during the charge-discharge process. Herein, sulfur-containing zwitter-molecule (methionine, Met) is used as an additive for ZnSO4 electrolytes. In electrolytes, Met reduces the H2 O coordination number and facilitates the desolvation process by virtue of functional groups (─COOH, ─NH2 , C─S─C), accelerating Zn2+ transference kinetics and decreasing the amount of active water. On electrodes, Met prefers to adsorb on Zn (002) plane and further transforms into a zincophilic protective layer containing C─SOx ─C through an in situ electrochemical oxidization, suppressing H2 evolution/corrosion reactions and guiding dendrite-free Zn deposition. By using Met-containing ZnSO4 electrolytes, the Zn//Zn cells show superior cycling performance under 30 mA cm-2 /30 mA h cm-2 . Moreover, the full cells Zn//NH4 V4 O10 full cells using the modified electrolytes exhibit good performance at temperatures from -8 to 60 °C. Notably, a high energy density of 105.30 W h kg-1 can be delivered using a low N/P ratio of 1.2, showing a promising prospect of Met electrolytes additives for practical use.

4.
Integr Zool ; 19(2): 183-199, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37231642

RESUMO

Understanding the competition and coexistence of flagship carnivores is key to creating strategies for their conservation in the face of global carnivore declines. Although studies exploring the dynamics and competition between tigers (Panthera tigris) and leopards (P. pardus) span decades, there is a lack of understanding regarding the factors that influence their coexistence mechanisms on a broad scale, as well as the drivers determining their exploitative and interference competition. We gathered a comprehensive list of research papers among which 36 papers explored the interspecific interactions between tigers and leopards and tested the influence of biotic and abiotic factors on the coexistence mechanisms along three dimensions using multiple response variables regression models; we also tested the influence of ecological drivers determining the exploitative or interference competition between tigers and leopards. Elevation and ungulate density were the most important predictors in regulating the coexistence mechanisms. Tigers and leopards exhibited more positive relations/higher overlaps as elevation increased in the spatial niche. In addition, they showed a higher dietary overlap in the prey-rich regions. We determined that interference competition between tigers and leopards was less frequently observed in habitats with dense tree cover and homogeneous vegetation structures. Meanwhile, studies with multiple metrics would promote the detection of interference competition. Our study provides new insight into the competitive interactions and coexistence mechanisms of tigers and leopards on a broad scale. Policy-makers and managers should pay more attention to the factors of elevation, prey abundance, and habitat structures for the conservation of tigers and leopards.


Assuntos
Panthera , Animais , Ásia , Simpatria , Árvores
5.
Regen Ther ; 25: 77-84, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38111468

RESUMO

Introduction: Angiogenesis plays an important role in the repair of urethral injury, and stem cells and their secretomes can promote angiogenesis. We obtained pediatric urethral mesenchymal stem-like cells (PU-MSLCs) in an earlier study. This project studied the pro-angiogenic effect of PU-MSLC-derived small extracellular vesicles (PUMSLC-sEVs) and the underlying mechanisms. Materials and methods: PUMSLCs and PUMSLC-sEVs were cultivated and identified. Then, biological methods such as the ethynyl deoxyuridine (EdU) incorporation assay, Cell Counting Kit-8 (CCK-8) assay, scratch wound assay, Transwell assay, and tube formation assay were used to study the effect of PUMSLC-sEVs on the proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs). We explored whether the proangiogenic effect of PUMSLC-sEVs is related to CD73 and whether adenosine (ADO, a CD73 metabolite) promoted angiogenesis. GraphPad Prism 8 software was used for data analysis. Results: We observed that PUMSLC-sEVs significantly promoted the proliferation, migration, and tube-forming abilities of HUVECs. PUMSLC-sEVs delivered CD73 molecules to HUVECs to promote angiogenesis. The angiogenic ability of HUVECs was enhanced after treatment with extracellular ADO produced by CD73, and PUMSLC-sEVs further promoted angiogenesis by activating Adenosine Receptor A2A (A2AR). Conclusions: These observations suggest that PUMSLC-sEVs promote angiogenesis, possibly through activation of the CD73/ADO/A2AR signaling axis.

6.
Infect Drug Resist ; 16: 7581-7586, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38107434

RESUMO

Background: Streptococcus constellatus rarely causes pyopneumothorax, which is a serious state and requires a surgery. However, not every patient can tolerate surgery and individualized solutions are needed. Furthermore, many known situations are risk factors of S. constellatus infection, but S. constellatus pyopneumothorax associated with Hashimoto's thyroiditis has not been reported. Case Presentation: We present the case of a 74-year-old male with multiple encapsulated pyopneumothorax caused by S. constellatus. Given his respiratory failure, we provided two-stage percutaneous right empyema radiography for catheter drainage in the radiology interventional department instead of surgery. Moreover, an occult Hashimoto's thyroiditis was discovered in the patient, which was possibly associated with S. constellatus pyopneumothorax. Levothyroxine was administered to improve his situation. Conclusion: To our knowledge, it is the first case described in this context. We provided an alternative treatment for S. constellatus encapsulated pyopneumothorax in patient who might not tolerate surgery. We also revealed the possible relationship between S. constellatus pyopneumothorax and Hashimoto's thyroiditis.

7.
Ecol Evol ; 13(10): e10634, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37859829

RESUMO

Environmental filtering is deemed to play a predominant role in regulating the abundance and distribution of animals during the urbanization process. However, the current knowledge about the effects of urbanization on the population densities of terrestrial mammals is limited. In this study, we compared two invasive mammals (dogs Canis lupus familiaris and cats Felis silvestris) and three indigenous mammals (Siberian weasels Mustela sibirica, Amur hedgehogs Erinaceus amurensis, and Tolai hares Lepus tolai) in response to urbanization using camera trap distance sampling (CTDS) in the rural-urban landscape of Tianjin, China. We used generalized additive mixed models (GAMMs) to test the specific responses of their densities to levels of urbanization. Invasive dogs (2.63 individuals/km2, 95% CI: 0.91-7.62) exhibited similar density estimations to cats (2.15 individuals/km2, 95% CI: 1.31-3.50). Amur hedgehogs were the most abundant species (6.73 individuals/km2, 95% CI: 3.15-14.38), followed by Tolai hares (2.22 individuals/km2, 95% CI: 0.87-5.68) and Siberian weasels (2.15 individuals/km2, 95% CI: 1.06-4.36). The densities of cats, Siberian weasels, and Amur hedgehogs increased with the level of urbanization. The population densities of dogs and cats were only influenced by urban-related variables, while the densities of Siberian weasels and Amur hedgehogs were influenced by both urban-related variables and nature-related variables. Our findings highlight that the CTDS is a suitable and promising method for wildlife surveys in rural-urban landscapes, and urban wildlife management needs to consider the integrated repercussions of urban- and nature-related factors, especially the critical impacts of green space habitats at finer scales.

8.
Nat Commun ; 14(1): 6689, 2023 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-37865633

RESUMO

Interlayer decoupling plays an essential role in realizing unprecedented properties in atomically thin materials, but it remains relatively unexplored in the bulk. It is unclear how to realize a large crystal that behaves as its monolayer counterpart by artificial manipulation. Here, we construct a superlattice consisting of alternating layers of NbSe2 and highly porous hydroxide, as a proof of principle for realizing interlayer decoupling in bulk materials. In (NaOH)0.5NbSe2, the electric decoupling is manifested by an ideal 1D insulating state along the interlayer direction. Vibration decoupling is demonstrated through the absence of interlayer models in the Raman spectrum, dominant local modes in heat capacity, low interlayer coupling energy and out-of-plane thermal conductivity (0.28 W/mK at RT) that are reduced to a few percent of NbSe2's. Consequently, a drastic enhancement of CDW transition temperature (>110 K) and Pauling-breaking 2D superconductivity is observed, suggesting that the bulk crystal behaves similarly to an exfoliated NbSe2 monolayer. Our findings provide a route to achieve intrinsic 2D properties on a large-scale without exfoliation.

10.
Phytomedicine ; 121: 155086, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37783132

RESUMO

BACKGROUND: Astragaloside IV (AS-IV) is the main active component of "Astragalus membranaceus (Fisch.) Bunge, a synonym of Astragalus propinquus Schischkin (Fabaceae)", which demonstrated to be useful for the treatment of intracerebral hemorrhage (ICH). However, due to the low bioavailability and barrier permeability of AS-IV, the gut microbiota may be an important key regulator for AS-IV to work. OBJECTIVE: To explore the influences of gut microbiota on the effects of AS-IV on ICH. METHODS: Mice were randomly divided into five groups: sham, ICH, and AS-IV-treated groups (25 mg/kg, 50 mg/kg, and 100 mg/kg). Behavioral tests, brain histopathology, and immunohistochemistry analysis were used to evaluate the degree of brain injury. Western blot was employed to verify peri­hematoma inflammation. The plasma lipopolysaccharide (LPS) leakage, the fluorescein isothiocyanate-dextran permeability, the colonic histopathology, and immunohistochemistry were detected to evaluate the barrier function of intestinal mucosal. Moreover, 16S rDNA sequencing and metabolomic analysis was applied to screen differential bacteria and metabolites, respectively. The correlation analysis was adopted to determine the potential relationship between differential bacteria and critical metabolites or neurological deficits. RESULTS: AS-IV alleviated neurological deficits, neuronal injury and apoptosis, and blood-brain barrier disruption. This compound reduced tumor necrosis factor (TNF)-α expression, increased arginase (Arg)-1 and interleukin (IL)-33 levels around the hematoma. Next, 16S rRNA sequencing indicated that AS-IV altered the gut microbiota, and inhibited the production of conditional pathogenic bacteria. Metabolomic analysis demonstrated that AS-IV regulated the serum metabolic profiles, especially the aminoacid metabolism and peroxisome proliferator-activated receptor (PPAR) signaling pathway. Additionally, AS-IV mitigated intestinal barrier damage and LPS leakage. CONCLUSION: This study provides a new perspective on the use of AS-IV for the treatment of ICH. Among them, gut microbiota and its metabolites may be the key regulator of AS-IV in treating ICH.


Assuntos
Microbioma Gastrointestinal , Lipopolissacarídeos , Camundongos , Animais , Lipopolissacarídeos/farmacologia , RNA Ribossômico 16S , Hemorragia Cerebral/tratamento farmacológico , Bactérias , Hematoma
11.
Nat Commun ; 14(1): 4700, 2023 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-37543693

RESUMO

A comorbidity of chronic pain is sleep disturbance. Here, we identify a dual-functional ensemble that regulates both pain-like behaviour induced by chronic constrictive injury or complete Freund's adjuvant, and sleep wakefulness, in the nucleus accumbens (NAc) in mice. Specifically, a select population of NAc neurons exhibits increased activity either upon nociceptive stimulation or during wakefulness. Experimental activation of the ensemble neurons exacerbates pain-like (nociceptive) responses and reduces NREM sleep, while inactivation of these neurons produces the opposite effects. Furthermore, NAc ensemble primarily consists of D1 neurons and projects divergently to the ventral tegmental area (VTA) and preoptic area (POA). Silencing an ensemble innervating VTA neurons selectively increases nociceptive responses without affecting sleep, whereas inhibiting ensemble-innervating POA neurons decreases NREM sleep without affecting nociception. These results suggest a common NAc ensemble that encodes chronic pain and controls sleep, and achieves the modality specificity through its divergent downstream circuit targets.


Assuntos
Dor Crônica , Núcleo Accumbens , Camundongos , Animais , Núcleo Accumbens/fisiologia , Área Tegmentar Ventral/fisiologia , Neurônios , Sono/fisiologia
12.
Entropy (Basel) ; 25(8)2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37628212

RESUMO

Remote sensing images are important data sources for land cover mapping. As one of the most important artificial features in remote sensing images, buildings play a critical role in many applications, such as population estimation and urban planning. Classifying buildings quickly and accurately ensures the reliability of the above applications. It is known that the classification accuracy of buildings (usually indicated by a comprehensive index called F1) is greatly affected by image quality. However, how image quality affects building classification accuracy is still unclear. In this study, Boltzmann entropy (an index considering both compositional and configurational information, simply called BE) is employed to describe image quality, and the potential relationships between BE and F1 are explored based on images from two open-source building datasets (i.e., the WHU and Inria datasets) in three cities (i.e., Christchurch, Chicago and Austin). Experimental results show that (1) F1 fluctuates greatly in images where building proportions are small (especially in images with building proportions smaller than 1%) and (2) BE has a negative relationship with F1 (i.e., when BE becomes larger, F1 tends to become smaller). The negative relationships are confirmed using Spearman correlation coefficients (SCCs) and various confidence intervals via bootstrapping (i.e., a nonparametric statistical method). Such discoveries are helpful in deepening our understanding of how image quality affects building classification accuracy.

13.
Int J Biol Macromol ; 253(Pt 1): 126545, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37652342

RESUMO

Understanding the physiological and molecular regulation of tick feeding is necessary for developing intervention strategies to curb disease transmission by ticks. Pharmacological activation of ATP-gated inward rectifier potassium (KATP) channels reduced fluid secretion from isolated salivary gland and blood feeding in the lone star tick, Amblyomma americanum, yet the temporal expression pattern of KATP channel proteins remained unknown. KATP channels were highly expressed in type II and III acini in off-host stage and early feeding phase ticks, yet expression was reduced in later stages of feeding. We next assessed KATP channel regulation of the secreted proteome of tick saliva. LC-MS/MS analysis identified 40 differentially secreted tick saliva proteins after exposure to KATP activators or inhibitors. Secretion of previously validated tick saliva proteins that promote tick feeding, AV422, AAS27, and AAS41 were significantly reduced by upwards of 8 log units in ticks exposed to KATP channel activators when compared to untreated ticks. Importantly, activation of KATP channels inhibited tick feeding and vice versa for KATP channel inhibitors. Data indicate KATP channels regulate tick feeding biology by controlling secretion of pro-feeding proteins that are essential during early feeding phases, which provides insights into physiological and molecular regulation of tick feeding behavior.


Assuntos
Ixodidae , Canais de Potássio Corretores do Fluxo de Internalização , Carrapatos , Animais , Amblyomma , Ixodidae/metabolismo , Canais KATP/metabolismo , Cromatografia Líquida , Espectrometria de Massas em Tandem , Carrapatos/metabolismo , Proteínas e Peptídeos Salivares , Trifosfato de Adenosina/metabolismo
14.
Sci Total Environ ; 904: 166322, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37586518

RESUMO

The Beijiang River, one of the Pearl River tributaries located in Guangdong, China, plays a critical role in providing water and fishery resources for the Pearl River Delta and receiving a large amount of domestic and industrial wastewater. However, due to the lack of historical monitoring data, we are unable to fully understand the relationship between the industrial and agricultural development and the environment. In this study, fish specimens collected from the Beijiang River Basin over a span of nearly 60 years (1963-2021) are used as research objects and the concentrations of ten trace metals (TMs) in two locally dominant fish species were determined by an inductively coupled plasma mass spectrometer. The human health risks caused by consuming fishes were assessed. Results show a correlation between the levels of TMs in fish muscle and the degree of industrialization. The concentrations of Cr, Mn, Ni, and Cu peaked during the period of 1981-1983, when China's industrial development was rapidly expanding while the environmental protection facilities were incomplete. However, with the implementation of Ecological Civilization policy, the levels of Cr, Mn, Ni, Cu, Cd, and Ba showed a downward trend in the period from 2018 to 2021. Cu concentrations in both fish muscle and viscera exhibit analogous change patterns across different periods, indicating that Cu serves as a significant indicator of TM pollution in the Beijiang River Basin. The presence of TMs in fish muscle often exhibits long-term enrichment, while those in the viscera demonstrate short-term accumulation. Based on the estimated daily intake, the target hazard quotient (THQ), and total THQ value, the overall health risk associated with TMs in fish from the Beijiang River Basin is low. However, certain TMs in the fish rebounded during 2018-2021, posing a potential risk for aquatic biology and ecosystems, which is worth our attention.


Assuntos
Metais Pesados , Oligoelementos , Poluentes Químicos da Água , Animais , Humanos , Rios , Metais Pesados/análise , Monitoramento Ambiental/métodos , Seguimentos , Ecossistema , Peixes , Medição de Risco , China , Oligoelementos/análise , Poluentes Químicos da Água/análise
15.
Mitochondrial DNA B Resour ; 8(8): 815-818, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37545549

RESUMO

Cymbidium wenshanense Y. S. Wu et F. Y. Liu is of significant ornamental and breeding value. In this study, Illumina high-throughput sequencing was used to sequence and analyze the complete chloroplast genome of C. wenshanense, and the phylogenetic relationships between this and other Orchidaceae species were established. The whole chloroplast genome was 156,292 bp in length and contained 84 mRNA genes, 45 tRNA genes, and 4 rRNA genes. The phylogenetic tree of 11 Orchidaceae species revealed C. wenshanense to be most closely related to Cymbidium mastersii.

16.
Pharm Biol ; 61(1): 1054-1064, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37416997

RESUMO

CONTEXT: Hydroxysafflor yellow A (HSYA) is the main bioactive ingredient of safflower (Carthamus tinctorius L., [Asteraceae]) for traumatic brain injury (TBI) treatment. OBJECTIVE: To explore the therapeutic effects and underlying mechanisms of HSYA on post-TBI neurogenesis and axon regeneration. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomly assigned into Sham, controlled cortex impact (CCI), and HSYA groups. Firstly, the modified Neurologic Severity Score (mNSS), foot fault test, hematoxylin-eosin staining, Nissl's staining, and immunofluorescence of Tau1 and doublecortin (DCX) were used to evaluate the effects of HSYA on TBI at the 14th day. Next, the effectors of HSYA on post-TBI neurogenesis and axon regeneration were screened out by pathology-specialized network pharmacology and untargeted metabolomics. Then, the core effectors were validated by immunofluorescence. RESULTS: HSYA alleviated mNSS, foot fault rate, inflammatory cell infiltration, and Nissl's body loss. Moreover, HSYA increased not only hippocampal DCX but also cortical Tau1 and DCX following TBI. Metabolomics demonstrated that HSYA significantly regulated hippocampal and cortical metabolites enriched in 'arginine metabolism' and 'phenylalanine, tyrosine and tryptophan metabolism' including l-phenylalanine, ornithine, l-(+)-citrulline and argininosuccinic acid. Network pharmacology suggested that neurotrophic factor (BDNF) and signal transducer and activator of transcription 3 (STAT3) were the core nodes in the HSYA-TBI-neurogenesis and axon regeneration network. In addition, BDNF and growth-associated protein 43 (GAP43) were significantly elevated following HSYA treatment in the cortex and hippocampus. DISCUSSION AND CONCLUSIONS: HSYA may promote TBI recovery by facilitating neurogenesis and axon regeneration through regulating cortical and hippocampal metabolism, BDNF and STAT3/GAP43 axis.


Assuntos
Lesões Encefálicas Traumáticas , Chalcona , Ratos , Masculino , Animais , Ratos Sprague-Dawley , Fator Neurotrófico Derivado do Encéfalo , Axônios , Regeneração Nervosa , Lesões Encefálicas Traumáticas/tratamento farmacológico , Quinonas/farmacologia , Chalcona/farmacologia , Metabolômica
17.
PeerJ ; 11: e15490, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37273531

RESUMO

Ornamental foliage plants have long been cultivated for their attractive leaves. Variation in leaf traits of ornamental foliage plants is one of the goals in breeding. MYB transcription factors regulate many aspects of leaf development, and thus influence morphological traits of leaves. However, little is known about the function of MYB transcription factors in leaf development of Cymbidium, one of the most economically important ornamental plants in the world. In the present study, a MYB transcription factor, CcMYB24, was identified and the corresponding gene cloned from a new orchid mutant, TRIR-2, which produces more leaves than control plants. The CcMYB24 showed a higher expression level in 'TRIR-2' than in control plants, and the protein was located in the nucleus. The sequence of CcMYB24 showed a high similarity with RAX2-like genes which belong to the R2R3-MYB gene family in other Cymbidium plants. Overexpression of CcMYB24 resulted in a phenotype with an increased number of leaves, elevated chlorophyll content, and decreased contents of carotenoids and flavonoids in Arabidopsis. These results provide functional evidence for the role of CcMYB24 in promoting the production of leaves in 'TRIR-2'. Understanding the role of CcMYB24 in Cymbidium will be beneficial for the molecular breeding of ornamental foliage plants.


Assuntos
Arabidopsis , Fatores de Transcrição , Fatores de Transcrição/genética , Arabidopsis/genética , Antocianinas , Proteínas de Plantas/genética , Regulação da Expressão Gênica de Plantas , Melhoramento Vegetal , Folhas de Planta/genética
18.
J Am Chem Soc ; 145(24): 13134-13146, 2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37278596

RESUMO

Stable metal nitrides (MN) are promising materials to fit the future "green" ammonia-hydrogen nexus. Either through catalysis or chemical looping, the reductive hydrogenation of MN to MN1-x is a necessary step to generate ammonia. However, encumbered by the formation of kinetically stable M-NH1─3 surface species, this reduction step remains challenging under mild conditions. Herein, we discovered that deleterious Ti-NH1─3 accumulation on TiN can be circumvented photochemically with supported single atoms and clusters of platinum (Pt1-Ptn) under N2-H2 conditions. The photochemistry of TiN selectively promoted Ti-NH formation, while Pt1-Ptn effectively transformed any formed Ti-NH into free ammonia. The generated ammonia was found to originate mainly from TiN reduction with a minor contribution from N2 activation. The knowledge accrued from this fundamental study could serve as a springboard for the development of MN materials for more efficient ammonia production to potentially disrupt the century-old fossil-powered Haber-Bosch process.

19.
Small ; 19(36): e2302357, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37127849

RESUMO

Low-dimensional hybrid metal halide (LDHMH) materials have attracted considerable attention owing to their intriguing optical properties. To the best of the knowledge, this is the first study to successfully demonstrate both self-trap exciton (STE) and afterglow emissions in Zr-based LDHMH materials. The obtained pure (Ph3 S)2 ZrCl6 crystals showed near-ultraviolet phosphorescence and a green afterglow owing to the organic cation Ph3 S+ , while the Bi-doped and Sb-doped crystals exhibited both STE and afterglow emissions. However, the Te-doped crystals showed only a broad yellow STE emission owing to the [TeCl6 ]2- octahedron. In addition, all the crystals showed good stability. Notably, Sb-doped crystals produced white light, which can be adjusted between cold white and warm white using different excitations. Finally, this strategy for both STE and afterglow emissions can be applied to other LDHMH materials for optical applications.

20.
Nat Commun ; 14(1): 2596, 2023 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-37147283

RESUMO

The interplay between quantum interference, electron-electron interaction (EEI), and disorder is one of the central themes of condensed matter physics. Such interplay can cause high-order magnetoconductance (MC) corrections in semiconductors with weak spin-orbit coupling (SOC). However, it remains unexplored how the magnetotransport properties are modified by the high-order quantum corrections in the electron systems of symplectic symmetry class, which include topological insulators (TIs), Weyl semimetals, graphene with negligible intervalley scattering, and semiconductors with strong SOC. Here, we extend the theory of quantum conductance corrections to two-dimensional (2D) electron systems with the symplectic symmetry, and study experimentally such physics with dual-gated TI devices in which the transport is dominated by highly tunable surface states. We find that the MC can be enhanced significantly by the second-order interference and the EEI effects, in contrast to the suppression of MC for the systems with orthogonal symmetry. Our work reveals that detailed MC analysis can provide deep insights into the complex electronic processes in TIs, such as the screening and dephasing effects of localized charge puddles, as well as the related particle-hole asymmetry.

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