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1.
Sensors (Basel) ; 19(24)2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31817605

RESUMO

Fish and some amphibians can perform a variety of behaviors in confined and harsh environments by employing an extraordinary mechanosensory organ, the lateral line system (LLS). Inspired by the form-function of the LLS, a hydrodynamic artificial velocity sensor (HAVS) was presented in this paper. The sensors featured a polarized poly (vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)]/barium titanate (BTO) electrospinning nanofiber mat as the sensing layer, a polyimide (PI) film with arrays of circular cavities as the substrate, and a poly(methyl methacrylate) (PMMA) pillar as the cilium. The P(VDF-TrFE)/BTO electrospinning nanofiber mat demonstrated enhanced crystallinity and piezoelectricity compared with the pure P(VDF-TrFE) nanofiber mat. A dipole source was employed to characterize the sensing performance of the fabricated HAVS. The HAVS achieved a velocity detection limit of 0.23 mm/s, superior to the conventional nanofiber mat-based flow sensor. In addition, directivity was feasible for the HAVS, which was in accordance with the simulation results. The proposed bio-inspired flexible lateral line sensor with hydrodynamic perception ability shows promising applications in underwater robotics for real-time flow analysis.

2.
J Integr Plant Biol ; 61(4): 463-477, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30129698

RESUMO

Legumes can control the number of symbiotic nodules that form on their roots, thus balancing nitrogen assimilation and energy consumption. Two major pathways participate in nodulation: the Nod factor (NF) signaling pathway which involves recognition of rhizobial bacteria by root cells and promotion of nodulation, and the autoregulation of nodulation (AON) pathway which involves long-distance negative feedback between roots and shoots. Although a handful of genes have a clear role in the maintenance of nodule number, additional unknown factors may also be involved in this process. Here, we identify a novel function for a Lotus japonicus ALOG (Arabidopsis LSH1 and Oryza G1) family member, LjALOG1, involved in positively regulating nodulation. LjALOG1 expression increased substantially after inoculation with rhizobia, with high levels of expression in whole nodule primordia and in the base of developing nodules. The ljalog1 mutants, which have an insertion of the LORE1 retroelement in LjALOG1, had significantly fewer nodules compared with wild type, along with increased expression of LjCLE-RS1 (L. japonicus CLE Root Signal 1), which encodes a nodulation suppressor in the AON pathway. In summary, our findings identified a novel factor that participates in controlling nodulation, possibly by suppressing the AON pathway.


Assuntos
Lotus/genética , Família Multigênica , Nodulação/genética , Regulação da Expressão Gênica de Plantas , Lotus/microbiologia , Mutagênese Insercional/genética , Mutação/genética , Filogenia , Plantas Geneticamente Modificadas , Rhizobium/fisiologia , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/microbiologia , Análise de Sequência de DNA
3.
New Phytol ; 215(4): 1582-1593, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28691160

RESUMO

The diverse pigmentation patterns of flower corollas probably result from pollinator-mediated selection. Previous studies demonstrated that R2R3-MYB factors may have been recruited in the regulation of corolla pigmentation. However, how R2R3-MYBs became so diverse in their regulation of different pigmentation patterns remains unclear. Here, we studied a Lamiales species, Torenia fournieri, which has elaborate zygomorphic flowers with dorsal-ventral asymmetries in corolla pigmentation. We found recent gene duplication events in CYCLOIDEA-like (CYC-like) and RADIALIS-like (RAD-like) genes, and functionally analyzed three dorsal-specific expression factors: TfCYC1, TfCYC2, and TfRAD1. We found that the CYC-RAD module coordinates petal shape and corolla pigmentation, as ectopic expression of TfCYC2 or TfRAD1 disrupted the asymmetric corolla pigmentation pattern and produced strongly dorsalized flowers. Dorsal petal identity was lost when TfCYC2 was down-regulated or when TfRAD1 was knocked out. In T. fournieri, the diversified CYC and RAD genes have evolved regulatory loops, and TfCYC2 binds directly to the regulatory regions of an R2R3-MYB factor gene, TfMYB1, which might lead to its asymmetric expression and ultimately establish the asymmetric pigmentation pattern. These findings support the existence of a regulatory module that integrates dorsal-ventral patterning and asymmetric corolla pigmentation in T. fournieri.


Assuntos
Flores/anatomia & histologia , Lamiaceae/anatomia & histologia , Lamiaceae/fisiologia , Pigmentação , Proteínas de Plantas/metabolismo , Antocianinas/metabolismo , Vias Biossintéticas/genética , Padronização Corporal , Clonagem Molecular , Flores/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Lamiaceae/genética , Modelos Biológicos , Fenótipo , Filogenia , Proteínas de Plantas/genética , Ligação Proteica , Sequências Reguladoras de Ácido Nucleico/genética
4.
Nanomaterials (Basel) ; 14(14)2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-39057851

RESUMO

The rapid progress of flexible electronics has met the growing need for detecting human movement information in exoskeleton auxiliary equipment. This study provides a review of recent advancements in the design and fabrication of flexible electronics used for human motion detection. Firstly, a comprehensive introduction is provided on various self-powered wearable flexible sensors employed in detecting human movement information. Subsequently, the algorithms utilized to provide feedback on human movement are presented, followed by a thorough discussion of their methods and effectiveness. Finally, the review concludes with perspectives on the current challenges and opportunities in implementing self-powered wearable flexible sensors in exoskeleton technology.

5.
Biomimetics (Basel) ; 9(3)2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38534875

RESUMO

Hydrodynamic pressure sensors offer an auxiliary approach for ocean exploration by unmanned underwater vehicles (UUVs). However, existing hydrodynamic pressure sensors often lack the ability to monitor subtle hydrodynamic stimuli in deep-sea environments. In this study, we present the development of a deep-sea hydrodynamic pressure sensor (DSHPS) capable of operating over a wide range of water depths while maintaining exceptional hydrodynamic sensing performance. The DSHPS device was systematically optimized by considering factors such as piezoelectric polyvinylidene fluoride-trifluoroethylene/barium titanate [P(VDF-TrFE)/BTO] nanofibers, electrode configurations, sensing element dimensions, integrated circuits, and packaging strategies. The optimized DSHPS exhibited a remarkable pressure gradient response, achieving a minimum pressure difference detection capability of approximately 0.11 Pa. Additionally, the DSHPS demonstrated outstanding performance in the spatial positioning of dipole sources, which was elucidated through theoretical charge modeling and fluid-structure interaction (FSI) simulations. Furthermore, the integration of a high Young's modulus packaging strategy inspired by fish skull morphology ensured reliable sensing capabilities of the DSHPS even at depths of 1000 m in the deep sea. The DSHPS also exhibited consistent and reproducible positioning performance for subtle hydrodynamic stimulus sources across this wide range of water depths. We envision that the development of the DSHPS not only enhances our understanding of the evolutionary aspects of deep-sea canal lateral lines but also paves the way for the advancement of artificial hydrodynamic pressure sensors.

6.
J Integr Plant Biol ; 55(3): 221-31, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23009172

RESUMO

CYCLOIDEA (CYC)-like TCP genes play key roles in dorsoventral differentiation of zygomorphic flowers in Papilionoideae legumes. In this study, we analyzed the kew mutants whose flowers lost lateral identity, and investigated the diverse functions of three LjCYC genes during zygomorphic flower development in the model legume Lotus japonicus. We showed that kew1 and kew3 are allelic mutants of LjCYC3, a CYC-like TCP gene. Through transgenic experiments, it was shown that LjCYC1 possesses dorsal activity similar to LjCYC2, and that LjCYC3 alone is sufficient to confer lateral activity, and an epistatic effect between dorsal and lateral activities was identified. Sequence analysis revealed a striking alteration at the 3' end of the LjCYC3 open reading frame (ORF) in comparison with those of LjCYC1 and LjCYC2 ORFs. Furthermore, it was found that LjCYC proteins could interact with each other and possess different activities by means of a transcriptional activity assay. Our data demonstrate that the sequence variation and the subsequent alteration of protein property play important roles in the functional diversity of different LjCYC genes in controlling zygomorphic flower development in Lotus japonicus.


Assuntos
Flores/crescimento & desenvolvimento , Flores/metabolismo , Lotus/crescimento & desenvolvimento , Lotus/metabolismo , Proteínas de Plantas/metabolismo , Flores/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Lotus/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo
7.
J Integr Plant Biol ; 55(8): 682-95, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23931744

RESUMO

Phosphatidylserine (PS), a quantitatively minor membrane phospholipid, is involved in many biological processes besides its role in membrane structure. One PS synthesis gene, PHOSPHATIDYLSERINE SYNTHASE1 (PSS1), has been discovered to be required for microspore development in Arabidopsis thaliana L. but how PSS1 affects postembryonic development is still largely unknown. Here, we show that PSS1 is also required for inflorescence meristem and organ development in Arabidopsis. Disruption of PSS1 causes severe dwarfism, smaller lateral organs and reduced size of inflorescence meristem. Morphological and molecular studies suggest that both cell division and cell elongation are affected in the pss1-1 mutant. RNA in situ hybridization and promoter GUS analysis show that expression of both WUSCHEL (WUS) and CLAVATA3 (CLV3) depend on PSS1. Moreover, the defect in meristem maintenance is recovered and the expression of WUS and CLV3 are restored in the pss1-1 clv1-1 double mutant. Both SHOOTSTEMLESS (STM) and BREVIPEDICELLUS (BP) are upregulated, and auxin distribution is disrupted in rosette leaves of pss1-1. However, expression of BP, which is also a regulator of internode development, is lost in the pss1-1 inflorescence stem. Our data suggest that PSS1 plays essential roles in inflorescence meristem maintenance through the WUS-CLV pathway, and in leaf and internode development by differentially regulating the class I KNOX genes.


Assuntos
Arabidopsis/enzimologia , CDPdiacilglicerol-Serina O-Fosfatidiltransferase/metabolismo , Topos Floridos/crescimento & desenvolvimento , Meristema/crescimento & desenvolvimento , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , CDPdiacilglicerol-Serina O-Fosfatidiltransferase/genética , Divisão Celular , Crescimento Celular , Topos Floridos/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Pleiotropia Genética , Proteínas de Homeodomínio/genética , Ácidos Indolacéticos/metabolismo , Meristema/metabolismo , Mutação , Fenótipo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo
8.
J Integr Plant Biol ; 55(5): 419-33, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23331609

RESUMO

Transcription factors and phytohormones have been reported to play crucial roles to regulate leaf complexity among plant species. Using the compound-leafed species Lotus japonicus, a model legume plant with five visible leaflets, we characterized four independent mutants with reduced leaf complexity, proliferating floral meristem (pfm), proliferating floral organ-2 (pfo-2), fused leaflets1 (ful1) and umbrella leaflets (uml), which were further identified as loss-of-function mutants of Arabidopsis orthologs LEAFY (LFY), UNUSUAL FLORAL ORGANS (UFO), CUP-SHAPED COTYLEDON 2 (CUC2) and PIN-FORMED 1 (PIN1), respectively. Comparing the leaf development of wild-type and mutants by a scanning electron microscopy approach, leaflet initiation and/or dissection were found to be affected in these mutants. Expression and phenotype analysis indicated that PFM/LjLFY and PFO/LjUFO determined the basipetal leaflet initiation manner in L. japonicus. Genetic analysis of ful1 and uml mutants and their double mutants revealed that the CUC2-like gene and auxin pathway also participated in leaflet dissection in L. japonicus, and their functions might influence cytokinin biogenesis directly or indirectly. Our results here suggest that multiple genes were interplayed and played conserved functions in controlling leaf complexity during compound leaf development in L. japonicus.


Assuntos
Lotus/crescimento & desenvolvimento , Lotus/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Lotus/genética , Folhas de Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo
9.
Plant Physiol ; 152(2): 797-807, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19955265

RESUMO

The endogenous trans-acting small interfering RNA (ta-siRNA) pathway plays a conserved role in adaxial-abaxial patterning of lateral organs in simple-leafed plant species. However, its function in compound-leafed species is largely unknown. Using the compound-leafed species Lotus japonicus, we identified and characterized two independent mutants, reduced leaflet1 (rel1) and rel3, whose most conspicuous defects in compound leaves are abaxialized leaflets and reduction in leaflet number. Concurrent mutations in REL genes also compromise flower development and result in radial symmetric floral organs. Positional cloning revealed that REL1 and REL3 encode the homologs of Arabidopsis (Arabidopsis thaliana) SUPPRESSOR OF GENE SILENCING3 and ARGONAUTE7/ZIPPY, respectively, which are key components of the ta-siRNA pathway. These observations, together with the expression and functional data, demonstrated that the ta-siRNA pathway plays conserved yet distinct roles in the control of compound leaf and flower development in L. japonicus. Moreover, the phenotypic alterations of lateral organs in ta-siRNA-deficient mutants and the regulation of downstream targets by the ta-siRNA pathway in L. japonicus were similar to those in the monocots but different from Arabidopsis, indicating many parallels between L. japonicus and the monocots in the control of lateral organ development by the ta-siRNA pathway.


Assuntos
Flores/crescimento & desenvolvimento , Lotus/genética , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , RNA Interferente Pequeno , Proteínas de Arabidopsis , Sequência de Bases , Mapeamento Cromossômico , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Teste de Complementação Genética , Lotus/crescimento & desenvolvimento , Lotus/metabolismo , Dados de Sequência Molecular , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo , Alinhamento de Sequência
10.
Proc Natl Acad Sci U S A ; 105(30): 10414-9, 2008 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-18650395

RESUMO

Floral zygomorphy (flowers with bilateral symmetry) has multiple origins and typically manifests two kinds of asymmetries, dorsoventral (DV) and organ internal (IN) asymmetries in floral and organ planes, respectively, revealing the underlying key regulators in plant genomes that generate and superimpose various mechanisms to build up complexity and different floral forms during plant development. In this study, we investigate the loci affecting these asymmetries during the development of floral zygomorphy in pea (Pisum sativum L.). Two genes, LOBED STANDARD 1 (LST1) and KEELED WINGS (K), were cloned that encode TCP transcription factors and have divergent functions to constitute the DV asymmetry. A previously undescribed regulator, SYMMETRIC PETALS 1 (SYP1), has been isolated as controlling IN asymmetry. Genetic analysis demonstrates that DV and IN asymmetries could be controlled independently by the two kinds of regulators in pea, and their interactions help to specify the type of zygomorphy. Based on the genetic analysis in pea, we suggest that variation in both the functions and interactions of these regulators could give rise to the wide spectrum of floral symmetries among legume species and other flowering plants.


Assuntos
Regulação da Expressão Gênica de Plantas , Genes de Plantas , Pisum sativum/genética , Clonagem Molecular , Flores/genética , Variação Genética , Genoma de Planta , Genômica/métodos , Modelos Genéticos , Mutação , Fenótipo , Filogenia , Mapeamento Físico do Cromossomo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição
11.
J Integr Plant Biol ; 53(10): 770-82, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21902804

RESUMO

Previous studies have demonstrated that petal shape and size in legume flowers are determined by two separate mechanisms, dorsoventral (DV) and organ internal (IN) asymmetric mechanisms, respectively. However, little is known about the molecular mechanisms controlling petal development in legumes. To address this question, we investigated petal development along the floral DV axis in Lotus japonicus with respect to cell and developmental biology by comparing wild-type legumes to mutants. Based on morphological markers, the entire course of petal development, from initiation to maturity, was grouped to define 3 phases or 13 stages. In terms of epidermal micromorphology from adaxial surface, mature petals were divided into several distinct domains, and characteristic epidermal cells of each petal differentiated at stage 9, while epidermal cells of all domains were observed until stage 12. TCP and MIXTA-like genes were found to be differentially expressed in various domains of petals at stages 9 and 12. Our results suggest that DV and IN mechanisms interplay at different stages of petal development, and their interaction at the cellular and molecular level guides the elaboration of domains within petals to achieve their ideal shape, and further suggest that TCP genes determine petal identity along the DV axis by regulating MIXTA-like gene expression.


Assuntos
Flores/crescimento & desenvolvimento , Lotus/crescimento & desenvolvimento , Padronização Corporal/genética , Flores/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Lotus/genética , Mutação/genética , Epiderme Vegetal/citologia
12.
J Integr Plant Biol ; 52(6): 528-35, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20590983

RESUMO

Previous study has shown that during zygomorphic development in garden pea (Pisum sativum L.), the organ internal (IN) asymmetry of lateral and ventral petals was regulated by a genetic locus, SYMMETRIC PETAL 1 (SYP1), while the dorsoventral (DV) asymmetry was determined by two CYC-like TCP genes or the PsCYC genes, KEELED WINGS (K) and LOBED STANDARD 1 (LST1). In this study, two novel loci, ELEPHANT EAR-LIKE LEAF 1 (ELE1) and ELE2 were characterized. These mutants exhibit a similar defect of IN asymmetry as syp1 in lateral and ventral petals, but also display pleiotropic effects of enlarged organ size. Genetic analysis showed that ELE1 and ELE2 were involved in same genetic pathway and the enlarged size of petals but not compound leaves in ele2 was suppressed by introducing k and lst1, indicating that the enlargement of dorsal petal in ele2 requires the activities of K and LST1. An experimental framework of comparative genomic mapping approach was set up to map and clone LjELE1 locus in Lotus japonicus. Cloning the ELE1 gene will shed light on the underlying molecular mechanism during zygomorphic development and further provide the molecular basis for genetic improvement on legume crops.


Assuntos
Pisum sativum/genética , Proteínas de Plantas/genética , Mapeamento Cromossômico , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Mutação , Pisum sativum/anatomia & histologia
13.
ACS Appl Mater Interfaces ; 12(52): 58317-58325, 2020 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-33320517

RESUMO

Carbon-based piezoresistive nanomaterials are widely used for the fabrication of flexible sensors. Although our previous work demonstrated that an electrical breakdown (EBD) process can endow a graphene/polyimide (G/PI) composite with piezoresistivity, the formation of EBD-induced electrical traces with high consistency in bulk nanocomposites remains a technical challenge. With the aim of developing highly sensitive flexible strain sensors using a batch fabrication process, we introduce herein a microscale EBD (µEBD) method to form localized piezoresistors with diverse shapes in a G/PI thin film. The results of scanning electron microscopy, Raman spectroscopy, and electromechanical tests indicate that high piezoresistivity is derived from the high porosity of the carbonized conductive traces generated by the µEBD process. The gauge factor of the µEBD-treated G/PI strain sensor is over 20 times greater than that of the as-prepared G/PI film, and the sensitivities of the strain sensors can be tuned by varying the applied current in the µEBD process. We also demonstrate the potential applications of µEBD-treated G/PI strain sensors in the fields of finger gesture detection, sound pressure measurement, and airflow sensing.

14.
Bioinspir Biomim ; 14(6): 066004, 2019 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-31434068

RESUMO

With the assistance of mechanosensory lateral line system, fish can perceive minute water motions in complex underwater environments. Inspired by the constriction within canal nearby canal neuromast in fish lateral line system, we proposed a novel canal artificial lateral line (CALL) device with constriction in canal nearby the sensing element. The designed CALL device consisted of a poly(vinylidene fluoride-trifluoroethylene)/polyimide cantilever as the sensing element and a polydimethylsiloxane (PDMS) microfluid canal. Two types of CALL devices, i.e., CALL with straight canal (S-CALL) and CALL with constriction canal (C-CALL), were developed and characterized employing a dipole source. Experimental results showed that the proposed C-CALL device achieved a pressure gradient detection limit of 0.64 Pa m-1, which was much lower than the S-CALL device. It indicates that the constriction in the canal nearby the sensing element could enhance the hydrodynamic pressure sensing performance of the CALL device. In addition, the constriction could modify the frequency response of the CALL device, and the C-CALL device achieved higher voltage output than S-CALL in high-frequency domain.


Assuntos
Biomimética/instrumentação , Peixes/fisiologia , Animais , Desenho de Equipamento , Hidrodinâmica , Sistema da Linha Lateral , Reologia/instrumentação
15.
ACS Appl Mater Interfaces ; 11(7): 7379-7386, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30676033

RESUMO

Piezoelectric polymers with good flexibility have attracted tremendous attention in wearable sensors and energy harvesters. As the piezoelectricity of polymers such as polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE)] is lower than that of their ceramic counterparts, various approaches have been employed to improve the piezoelectric output of PVDF-based sensors, such as electrospinning, heat annealing, nanoconfinement, polymer blending, and nanoparticle addition. Here, we report two strategies to improve the piezoelectric sensing performance of polymer-based piezoelectric nanofibers, which include the formation of barium titanate (BTO)/P(VDF-TrFE) composite nanofibers and fabrication of penetrated electrodes to enlarge the interfacial area. BTO/P(VDF-TrFE) nanofibers with a BTO weight fraction of 5 wt % exhibit the maximum ß-phase crystallinity and piezoelectricity. The piezoelectric output of the BTO/P(VDF-TrFE) nanofiber mat is significantly improved compared with that of pristine P(VDF-TrFE), which is confirmed by piezoresponse force microscopy (PFM) and compression loading tests. In order to form the penetrated electrodes, oxygen (O2) plasma treatment is employed, followed by an electroless plating process. The BTO/P(VDF-TrFE) nanofibers with penetrated electrodes demonstrate increased dielectric constants and enhanced piezoelectric outputs. A BTO/P(VDF-TrFE) nanofiber-based sensor with penetrated electrodes is capable of discerning the energy of a free-falling ball as low as 0.6 µJ and sensing the movement of a walking ant.

16.
Polymers (Basel) ; 10(4)2018 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30966399

RESUMO

Piezoelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) nanofibers fabricated by electrospinning have drawn increasing levels of attention in the fields of flexible sensors and nanogenerators. However, the directional dependence of piezoelectricity of electrospun nanofibers remains elusive. In this study, the piezoelectric performances of individual nanofibers are characterized by piezoresponse force microscopy (PFM), while the effects of annealing on ß-phase crystallinities are investigated by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The experimental results reveal that the as-spun P(VDF-TrFE) nanofibers form higher content of ß-phase compared with spin-coated films, and the content of ß-phase increases by annealing. The annealed P(VDF-TrFE) nanofiber exhibits distinct vertical polarization switching characteristics. The high piezoelectric output in the thickness direction and low piezoelectric output in the longitudinal direction of the nanofiber mats further confirm that the preferential dipole orientation of electrospun P(VDF-TrFE) nanofibers is normal to the surface of the substrate. Highly aligned P(VDF-TrFE) nanofibers show directional strain sensing ability due to the piezoelectric and mechanical anisotropy.

17.
Am J Clin Nutr ; 105(6): 1291-1296, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28356277

RESUMO

Background: Evidence for the effect of dietary sodium intake on the risk of cardiovascular disease has been controversial. One of the main explanations for the conflicting results lies in the great variability associated with measurement methods for sodium intake. Spot urine collection is a convenient method commonly used for sodium estimation, but its validity for predicting 24-h urinary sodium excretion at the individual level has not been well evaluated among the general population.Objective: The aim of this study was to evaluate the validity of the Kawasaki, the International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT), and the Tanaka formulas in predicting 24-h urinary sodium excretion by using spot urine samples in Chinese adults.Design: We analyzed the relative and absolute differences and misclassification at the individual level from 3 commonly used methods for estimating sodium intake among 141 Chinese community residents.Results: The mean measured 24-h sodium excretion was 220.8 mmol/d. The median (95% CIs) differences between measured sodium and those estimated from the Kawasaki, INTERSALT, and Tanaka methods were 6.4 mmol/d (-17.5, 36.8 mmol/d), -67.3 mmol/d (-96.5, -46.9 mmol/d), and -42.9 mmol/d (-59.1, -24.8 mmol/d), respectively. The proportions of relative differences >40% with the Kawasaki, INTERSALT, and Tanaka methods were 31.2%, 41.1%, and 22.0%, respectively; and the absolute difference for the 3 methods was >51.3 mmol/d (3 g salt) in approximately half of the participants. The misclassification rate was 63.1% for the Kawasaki method, 78.7% for the INTERSALT method, and 66.0% for the Tanaka method at the individual level.Conclusion: The results from our study do not support the use of spot urine to estimate 24-h urinary sodium excretion at the individual level because of its poor performance with respect to misclassification. This trial was registered at www.chictr.org.cn as ChiCTR-IOR-16010278.


Assuntos
Cloreto de Sódio na Dieta/urina , Sódio/urina , Adulto , Povo Asiático , Pressão Sanguínea , Dieta , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Reprodutibilidade dos Testes , Sódio/administração & dosagem , Sódio/farmacocinética , Cloreto de Sódio na Dieta/administração & dosagem , Cloreto de Sódio na Dieta/farmacocinética , Sódio na Dieta/farmacocinética , Sódio na Dieta/urina
18.
J Plant Physiol ; 163(4): 436-44, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16455357

RESUMO

CENTRORADIALIS/TERMINAL FLOWER 1 (CEN/TFL1) genes play an important role in the phase transition of plant flowering. Here we characterized the expression pattern of a CEN/TFL1-like gene, Ljcen1, from Lotus japonicus. Sequence analysis revealed that Ljcen1 shared 67-76% identity to its homologs from a variety of plant species. Ljcen1 transcripts could be detected at the young root tip and reproductive shoot apical meristem of L. japonicus. RNA in situ hybridization analysis revealed that Ljcen1 was continuously expressed in the sub-domain of the primary inflorescence meristem and transiently expressed in the secondary inflorescence meristem. The ectopic expression of Ljcen1 in Arabidopsis driven by double CaMV 35S promoter delayed the flowering. These results suggested that Ljcen1 gene was involved in a conserved CEN/TFL1 pathway that functions in phase transition of shoot apical meristem in L. japonicus.


Assuntos
Lotus/crescimento & desenvolvimento , Proteínas de Plantas/fisiologia , Sequência de Aminoácidos , Arabidopsis/genética , Sequência de Bases , Flores/anatomia & histologia , Flores/genética , Flores/crescimento & desenvolvimento , Genes de Plantas , Lotus/genética , Lotus/metabolismo , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Brotos de Planta/anatomia & histologia , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plantas Geneticamente Modificadas/anatomia & histologia , Plantas Geneticamente Modificadas/metabolismo , Alinhamento de Sequência , Análise de Sequência
19.
Mol Plant ; 9(5): 722-736, 2016 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-26854849

RESUMO

In Papilionoideae legume, Lotus japonicus, the development of dorsal-ventral (DV) asymmetric flowers is mainly controlled by two TB1/CYCLOIDEA/PCF (TCP) genes, SQUARED STANDARD (SQU) and KEELED WINGS IN LOTUS (KEW), which determine dorsal and lateral identities, respectively. However, the molecular basis of how these two highly homologous genes orchestrate their diverse functions remains unclear. Here, we analyzed their expression levels, and investigated the transcriptional activities of SQU and KEW. We demonstrated that SQU possesses both activation and repression activities, while KEW acts only as an activator. They form homo- and heterodimers, and then collaboratively regulate their expression at the transcription level. Furthermore, we identified two types of post-transcriptional modifications, phosphorylation and ATP/GTP binding, both of which could affect their transcriptional activities. Mutations in ATP/GTP binding motifs of SQU and KEW lead to failure of phosphorylation, and transgenic plants bearing the mutant proteins display defective DV asymmetric flower development, indicating that the two conjugate modifications are essential for their diverse functions. Altogether, SQU and KEW activities are precisely modulated at both transcription and post-transcription levels, which might link DV asymmetric flower development to different physiological status and/or signaling pathways.


Assuntos
Flores/crescimento & desenvolvimento , Flores/metabolismo , Lotus/crescimento & desenvolvimento , Lotus/metabolismo , Proteínas de Plantas/metabolismo , Trifosfato de Adenosina/metabolismo , Flores/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Guanosina Trifosfato/metabolismo , Lotus/genética , Mutação/genética , Fosforilação/genética , Fosforilação/fisiologia , Proteínas de Plantas/genética , Ligação Proteica/genética , Ligação Proteica/fisiologia , Processamento de Proteína Pós-Traducional/genética , Processamento de Proteína Pós-Traducional/fisiologia
20.
Artigo em Inglês | MEDLINE | ID: mdl-15627706

RESUMO

The LjCYC1 (Lotus japonicus Cycloidea-like 1) gene, a homolog of CYC (Cycloidea) belonging to the TCP [TB1(teosinte branched 1), CYC, PCFs (PCF1 and PCF2)] gene family and encoding a predicted transcription factor and being proposed controlling different aspects of plant development, was isolated from the papilionaceous plant Lotus japonicus by screening the genomic DNA library, in order to test the functional conservation and divarication of CYC-like genes in legume. Sequence analyses indicate that LjCYC1 gene contains two exons and one intron and encodes a 370-AA peptide LjCYC1. The putative protein, LjCYC1, contains a TCP domain and an R domain, being a member of the CYC/TB1 subfamily of TCP family, and has 39.0% identity with and 42.6% similarity to CYC. LjCYC1-cDNA was cloned through RT-PCR. Different regions of the LjCYC1-cDNA were fused with the report gene GUS and then the fused constructs were transiently expressed in the onion epidermal cells through particle bombardment. Results of GUS and DAPI staining showed that the chimeric proteins with TCP domain were localized within the nucleus, confirming that LjCYC1 may act as a transcription factor. But the TCP domain itself could not confer the nuclear localization because the chimeric proteins with TCP domain alone were dispersed all over the transformed cells.


Assuntos
Genes de Plantas , Lotus/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Clonagem Molecular , Proteínas de Ligação a DNA , Dosagem de Genes , Lotus/química , Dados de Sequência Molecular , Sinais de Localização Nuclear , Fatores de Transcrição
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