RESUMO
Achieving water splitting to produce green H2 , using the noble-metal-free MoS2 , has attracted huge interest from researchers. However, tuning the number of MoS2 layers precisely while obtaining small lateral sizes to surge the H2 -evolution rate is a tremendous challenge. Here, a bottom-up strategy is designed for the in situ growth of ultrasmall lateral-sized MoS2 with tunable layers on CdS nanorods (CN) by controlling the decomposition temperature and concentration of substrate seed (NH4 )2 MoS4 . Here, the bilayer MoS2 and CN coupling (2L-MoS2 /CN) exhibits the optimum photocatalytic activity. Compared to thicker MoS2 , the 2L-MoS2 has sufficient reduction capacity to drive photocatalytic H2 evolution and the ultrasmall lateral size provides more active sites. Meanwhile, the indirect bandgap, in contrast to the direct bandgap of the monolayer MoS2 , suppresses the carrier recombination transferred to 2L-MoS2 . Under the synergistic effect of both, 2L-MoS2 /CN has fast surface chemical reactions, resulting in the photocatalytic H2 -evolution rate of up to 41.86 mmol g-1 h-1 . A novel strategy is provided here for tuning the MoS2 layers to achieve efficient H2 evolution.
RESUMO
The fabrication of periodic macroporous (PM) in Nb2O5 via morphological control is crucial for improving the photocatalytic hydrogen evolution efficiency. In this study, Nb2O5 with PM is synthesized using a straightforward colloidal crystal templating approach. This material features an open, interconnected macroporous architecture with nanoscale walls, high crystallinity, and substantial porosity. Extensive characterization reveals that this hierarchically structured Nb2O5 possesses abundant surface active sites and is capable of capturing light effectively, facilitating rapid mass transfer and diffusion of reactants and markedly suppressing the recombination of photoexcited charge carriers. Macroporous Nb2O5 exhibits superior water-splitting hydrogen evolution performance compared with its bulk and commercial counterparts, achieving a hydrogen production rate of 405 µmol g-1 h-1, surpassing that of bulk Nb2O5 (B-Nb2O5) and commercial Nb2O5 (C-Nb2O5) by factors of 5 and 33, respectively. This study proposes an innovative strategy for the design of hierarchically structured PM, thereby significantly advancing the hydrogen evolution potential of Nb2O5.
RESUMO
Plant height and tiller number are two major factors determining plant architecture and yield. However, in rice (Oryza sativa), the regulatory mechanism of plant architecture remains to be elucidated. Here, we reported a recessive rice mutant presenting dwarf and reduced tillering phenotypes (drt1). Map-based cloning revealed that the phenotypes are caused by a single point mutation in DRT1, which encodes the Class I formin protein O. sativa formin homolog 13 (OsFH13), binds with F-actin, and promotes actin polymerization for microfilament organization. DRT1 protein localized on the plasma membrane (PM) and chloroplast (CP) outer envelope. DRT1 interacted with rice phototropin 2 (OsPHOT2), and the interaction was interrupted in drt1. Upon blue light stimulus, PM localized DRT1 and OsPHOT2 were translocated onto the CP membrane. Moreover, deficiency of DRT1 reduced OsPHOT2 internalization and OsPHOT2-mediated CP relocation. Our study suggests that rice formin protein DRT1/OsFH13 is necessary for plant morphology and CP relocation by modulating the actin-associated cytoskeleton network.
Assuntos
Actinas , Oryza , Actinas/metabolismo , Oryza/metabolismo , Forminas/genética , Forminas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Cloroplastos/metabolismo , Mutação/genética , Regulação da Expressão Gênica de PlantasRESUMO
Macrohaplotype combines multiple types of phased DNA variants, increasing forensic discrimination power. High-quality long-sequencing reads, for example, PacBio HiFi reads, provide data to detect macrohaplotypes in multiploidy and DNA mixtures. However, the bioinformatics tools for detecting macrohaplotypes are lacking. In this study, we developed a bioinformatics software, MacroHapCaller, in which targeted loci (i.e., short TRs [STRs], single nucleotide polymorphisms, and insertion and deletions) are genotyped and combined with novel algorithms to call macrohaplotypes from long reads. MacroHapCaller uses physical phasing (i.e., read-backed phasing) to identify macrohaplotypes, and thus it can detect multi-allelic macrohaplotypes for a given sample. MacroHapCaller was validated with data generated from our designed targeted PacBio HiFi sequencing pipeline, which sequenced â¼8-kb amplicon regions harboring 20 core forensic STR loci in human benchmark samples HG002 and HG003. MacroHapCaller also was validated in whole-genome long-read sequencing data. Robust and accurate genotyping and phased macrohaplotypes were obtained with MacroHapCaller compared with the known ground truth. MacroHapCaller achieved a higher or consistent genotyping accuracy and faster speed than existing tools HipSTR and DeepVar. MacroHapCaller enables efficient macrohaplotype analysis from high-throughput sequencing data and supports applications using discriminating macrohaplotypes.
Assuntos
Haplótipos , Sequenciamento de Nucleotídeos em Larga Escala , Polimorfismo de Nucleotídeo Único , Poliploidia , Análise de Sequência de DNA , Software , Humanos , Análise de Sequência de DNA/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Algoritmos , Biologia Computacional/métodos , DNA/genética , DNA/análise , Repetições de Microssatélites/genética , Genética Forense/métodos , Técnicas de Genotipagem/métodosRESUMO
Water-to-land transition is a hallmark of terrestrialization for land plants and requires molecular adaptation to resist water deficiency. Lineages- or species-specific genes are widespread across eukaryotes, and yet the majority of those are functionally unknown and not annotated. Recent studies have revealed that some of such genes could play a role in adapting to environmental stress responses. Here, we identified a novel gene PpBCG1 (Bryophyte Co-retained Gene 1) in the moss Physcomitrium patens that was responsive to dehydration and rehydration. Under de- and rehydration treatments, PpBCG1 was significantly co-expressed with the dehydrin-encoding gene PpDHNA. Microarray data revealed that PpBCG1 was highly expressed in tissues of spores, female organ archegonia, and mature sporophytes. In addition, the Ppbcg1 mutant showed reduced ability of dehydration tolerance, whose plants were accompanied by a relatively low level of chlorophyll content during recovery. Comprehensive transcriptomics uncovered a detailed set of regulatory processes that were affected by the PpBCG1 disruption. Moreover, experimental evidence showed that PpBCG1 might function in the antioxidant activity, abscisic acid (ABA) pathway, and intracellular calcium (Ca2+) homeostasis to resist desiccation. Together, our study provides insights into the roles of one bryophyte co-retained gene in the desiccation tolerance.
RESUMO
Stress has been considered as a potential trigger for hair loss through the neuroendocrine-hair follicle (HF) axis. Neurotensin (NTS), a neuropeptide, is known to be dysregulated in the inflammatory-associated skin diseases. However, the precise role of NTS in stress-induced hair loss is unclear. To investigate the function and potential mechanisms of NTS in stress-induced hair growth inhibition, we initially detected the expression of neurotensin receptor (Ntsr) and NTS in the skin tissues of stressed mice by RNA-sequencing and ELISA. We found chronic restraint stress (CRS) significantly decreased the expression of both NTS and Ntsr in the skin tissues of mice. Intracutaneous injection of NTS effectively counteracted CRS-induced inhibition of hair growth in mice. Furthermore, NTS regulated a total of 1093 genes expression in human dermal papilla cells (HDPC), with 591 genes being up-regulated and 502 genes being down-regulated. GO analysis showed DNA replication, cell cycle, integral component of plasma membrane and angiogenesis-associated genes were significantly regulated by NTS. KEGG enrichment demonstrated that NTS also regulated genes related to the Hippo signalling pathway, axon guidance, cytokine-cytokine receptor interaction and Wnt signalling pathway in HDPC. Our results not only uncovered the potential effects of NTS on stress-induced hair growth inhibition but also provided an understanding of the mechanisms at the gene transcriptional level.
Assuntos
Cabelo , Neurotensina , Animais , Humanos , Camundongos , Alopecia/metabolismo , Folículo Piloso/metabolismo , Neuropeptídeos/metabolismo , Neurotensina/genética , Neurotensina/metabolismo , Neurotensina/farmacologia , Receptores de Neurotensina/genética , Receptores de Neurotensina/metabolismo , Cabelo/crescimento & desenvolvimento , Cabelo/metabolismoRESUMO
Highly ordered periodic macroporous structures have been extensively utilized to significantly enhance the photocatalytic activity. However, constructing 3D interconnected ordered porous ternary nanostructures with highly crystalline frameworks remains a formidable challenge. Here, we introduce the design and fabrication of 3D interconnected periodic macroporous NaNbO3 (PM NaNbO3) to effectively increase the density of surface-active sites and optimize the photogenerated carrier-transfer efficiency. By incorporating Pt as a cocatalyst, PM NaNbO3 exhibits an exceptional photocatalytic hydrogen generation rate of 10.04 mmol h-1 g-1, which is approximately six and five times higher than those of calcined NaNbO3 (C-NaNbO3) and hydrothermal NaNbO3 (H-NaNbO3), respectively. This outstanding performance can be attributed to the synergistic effects arising from its well-interconnected pore architecture, large surface area, enhanced light absorption capability, and improved charge carrier separation and transport efficiency. The findings presented in this study demonstrate an innovative approach toward designing hierarchically periodic macroporous materials for solar-driven hydrogen production.
RESUMO
Existing optical information hiding algorithms for multiple images require generating hidden keys for embedded images, resulting in the transmission of numerous keys. This challenge undermines the usage of these algorithms in low-quality networks. To address this issue and enhance transmission efficiency, we present a multi-image optical information hiding algorithm based on Fourier transformation principles, which is employed to generate hidden frequency maps and carrier frequency maps. Specific low-frequency information zones are extracted within these hidden frequency maps. A chaotic system integrates a phase mask, modulated with the low-frequency regions, positioned in the carrier frequency map's high-frequency sector. The final stego image is obtained by subjecting the carrier frequency map to inverse Fourier transformation. Experimental analysis shows that concealing three images takes only 0.0089 s, with extraction requiring 0.0658 s. Post-extraction PSNR values for hidden images exceed 32 dB. Robustness and anti-attack experiments were done to prove the security of this algorithm. The compared experiments between the proposed method and other state-of-the-art algorithms affirm the algorithm's attributes of simplicity, ease of implementation, robust security, and high efficiency. Importantly, the restoration process eliminates the necessity of transmitting hidden keys, reducing network burdens and enhancing both concealment and extraction efficiencies significantly.
RESUMO
Although the knee joint (KNJ) and temporomandibular joint (TMJ) all belong to the synovial joint, there are many differences in developmental origin, joint structure and articular cartilage type. Studies of joint development in embryos have been performed, mainly using poultry and rodents. However, KNJ and TMJ in poultry and rodents differ from those in humans in several ways. Very little work has been done on the embryonic development of KNJ and TMJ in large mammals. Several studies have shown that pigs are ideal animals for embryonic development research. Embryonic day 30 (E30), E35, E45, E55, E75, E90, Postnatal day 0 (P0) and Postnatal day 30 (P30) embryos/fetuses from the pigs were used for this study. The results showed that KNJ develops earlier than TMJ. Only one mesenchymal condensate of KNJ is formed on E30, while two mesenchymal condensates of TMJ are present on E35. All structures of KNJ and TMJ were formed on E45. The growth plate of KNJ begins to develop on E45 and becomes more pronounced from E55 to P30. From E75 to E90, more and more vascular-rich cartilage canals form in the cartilage regions of both joints. The cartilaginous canal of the TMJ divides the condyle into sections along the longitudinal axis of the condyle. This arrangement of cartilaginous canal was not found in the KNJ. The chondrification of KNJ precedes that of TMJ. Ossification of the knee condyle occurs gradually from the middle to the periphery, while that of the TMJ occurs gradually from the base of the mandibular condyle. In the KNJ, the ossification of the articular condyle is evident from P0 to P30, and the growth plate is completely formed on P30. In the TMJ, the cartilage layer of condyle becomes thinner from P0 to P30. There is no growth plate formation in TMJ during its entire development. There is no growth plate formation in the TMJ throughout its development. The condyle may be the developmental center of the TMJ. The chondrocytes and hypertrophic chondrocytes of the growth plate are densely arranged. The condylar chondrocytes of TMJ are scattered, while the hypertrophic chondrocytes are arranged. Embryonic development of KNJ and TMJ in pigs is an important bridge for translating the results of rodent studies to medical applications.
Assuntos
Articulação do Joelho , Articulação Temporomandibular , Animais , Suínos/embriologia , Articulação Temporomandibular/embriologia , Articulação Temporomandibular/crescimento & desenvolvimento , Articulação do Joelho/embriologia , Articulação do Joelho/crescimento & desenvolvimento , Cartilagem Articular/embriologia , Cartilagem Articular/crescimento & desenvolvimento , Feminino , Desenvolvimento Embrionário/fisiologia , Embrião de MamíferosRESUMO
Cathaya argyrophylla [Chun & Kuang.] is an ancient relict plant and its embryonic development is similar to that of Pinus species. This has important scientific value for studying the phylogeny of Pinaceae (Wu et al. 2023). In July 2022, root rot was detected in the seedling cultivation base of C. argyrophylla in Daozhen County, Guizhou Province, China (28.89 °N, 107.6 °E). The incidence of the disease was 30% (n = 100); the susceptible plants wilted, leaves withered, and roots showed brown-to-black lesions and rot. Ten root tissues were randomly collected from the edges of the lesions of six symptomatic susceptible plants. The tissues were sterilized with 75% alcohol for 30 seconds, followed by 2-minute immersion in 3% sodium hypochlorite. After washing with sterile water, the tissues were incubated on potato dextrose agar (PDA; BoWei, Shanghai) at 28 â for five days. Four single-spore cultures were obtained using a single-spore isolation method (Gong et al., 2010). Single-spore cultures grew rapidly on PDA. After five days of incubation, the colonies were white and pink, indicating a large amount of aerial mycelia. Microconidia were ovate or ellipsoid, measuring 5.0-10.0 × 1.5-3.0 µm (n = 50); Macroconidia were falcate, slightly curved or straight, measuring 19.5-28.5 × 2.0-6.0 µm (n = 50). Based on morphological features, the pathogen was considered to be Fusarium spp. (Leslie and Summerell 2006). Three representative strains, GF5, GF6, and GF7, were selected for molecular identification, and genomic DNA was extracted to confirm morphological diagnosis. The internal transcribed spacer (ITS) (White et al. 1990) was amplified using primers ITS1/ITS4, and the ß-tubulin gene (Varga et al. 2011) was amplified using primers Bt2a/Bt2b. The ITS and ß-tubulin sequences were aligned with GenBank, and amplification of the genes from the three isolates was consistent. The ITS (OP482273) and ß-tubulin (OR825353) sequences of GF5 were stored in GenBank, and their homology with Fusarium oxysporum HC131(accession numbers MW600442 and MW670451) was 99 to 100%. Maximum likelihood analysis using MEGA 11.0 showed that isolate GF5 belongs to F. oxysporum. The reconstructed phylogenetic tree confirmed the phylogenetic position of the isolate GF5. The pathogenicity test was carried out using GF5 and GF6 isolates. The taproots of ten 3-year-old C. argyrophylla plants were washed, and then the roots were immersed in a 2 × 106/mL conidial suspension for one hour. Ten plants with sterile water were used as controls. After planting in pots (30 × 25 cm) with sterilized forest soil, the plants were cultured in a greenhouse (25 â and 12-hour photoperiod). Thirty days after inoculation, all plants inoculated with the isolated pathogen showed wilting symptoms, and the roots showed typical root rot symptoms, whereas the control group showed no symptoms. The pathogens re-isolated from all inoculated plants were morphologically identical and had ITS sequences identical to F. oxysporum, validating Koch's hypothesis. The pathogenicity test was repeated twice and similar results were obtained. Although this fungus has been previously reported to cause root diseases in hosts, such as Musa nana Lour. and Pinus massoniana Lamb. (He et al. 2010; Luo et al. 2020), to our knowledge, this is the first report of F. oxysporum causing root rot in C. argyrophylla. These findings provide a basis for the development of management strategies for C. argyrophylla infection.
RESUMO
Tomato is a widely cultivated fruit and vegetable and is valued for its flavor, colour, and nutritional value. C6-aldehydes, such as (E)-2-hexenal, not only have antibacterial and antifungal properties but also function as signaling molecules that control the defense mechanisms of plants, including tomatoes. In this study, we used liquid chromatography-mass spectrometry (LC-MS) and RNA sequencing techniques to generate metabolome and transcriptome datasets that elucidate the molecular mechanisms regulating defense responses in tomato leaves exposed to (E)-2-hexenal. A total of 28.27 Gb of clean data were sequenced and assembled into 23,720 unigenes. In addition, a non-targeted metabolomics approach detected 739 metabolites. There were 233 significant differentially expressed genes (DEGs) (158 up-regulated, 75 down-regulated) and 154 differentially expressed metabolites (DEMs) (86 up-regulated, 69 down-regulated). Most nucleotides and amino acids (L-Phenylalanine, L-Asparagine, L-Histidine, L-Arginine, and L-Tyrosine) and their derivatives were enriched. The analyses revealed that mitogen-activated protein kinase (MPK), pathogenesis-related protein (PR), and endochitinase (CHIB) were primarily responsible for the adaptation of plant defense responses. Therefore, the extensive upregulation of these genes may be associated with the increased plant defense response. These findings help us comprehend the defense response of plants to (E)-2-hexenal and improve the resistance of horticultural plants.
Assuntos
Solanum lycopersicum , Transcriptoma , Solanum lycopersicum/genética , Fumigação , Metaboloma , Aldeídos/química , Mecanismos de Defesa , Regulação da Expressão Gênica de PlantasRESUMO
BACKGROUND: Solely relying on the tibial ankle surface (TAS) angle for determining the mechanical ankle axis might be insufficient. We introduce a novel method to determine the distance from the center of the talus to the tibial axis (TTD). This study aimed to investigate the association between clinical outcomes and radiological changes before and after supramalleolar osteotomy (SMO), including TAS angle, talar tilt (TT) angle, tibiotalar surface (TTS) angle and TTD. METHODS: Seventy patients who received SMO were enrolled. Radiological changes were measured using weight-bearing anteroposterior imaging. The percentage of talar center displacement (TTDP) was calculated as the difference between postoperative and preoperative TTD, divided by talar width (TW). Clinical assessments were performed using the American Orthopedic Foot and Ankle Society ankle-hindfoot (AOFAS) scale. Differences in the aforementioned indicators before and after the operation were analyzed. We defined ΔAOFAS, ΔTAS, ΔTT and ΔTTS as the difference between postoperative and preoperative values. RESULTS: ΔTTS correlated with ΔAOFAS (r = 0.40, p = 0.008), as did TTDP (r = 0.32, p = 0.035). No correlation was observed between ΔAOFAS and ΔTAS. In the comparison between groups, patients with a TTDP greater than 26.19 exhibited a significantly greater ΔAOFAS. The high intraclass correlation coefficient indicated good reliability of the novel method. CONCLUSION: Solely relying on the TAS angle for tibial correction was insufficient. We found TTD as a novel method to evaluate mechanical ankle joint axis. TTDP and ΔTTS both positively correlated with ΔAOFAS, indicating the usefulness of these radiologic parameters.
RESUMO
Aqueous Zn-ion batteries are an attractive electrochemical energy storage solution for their budget and safe properties. However, dendrites and uncontrolled side reactions in anodes detract the cycle life and energy density of the batteries. Grain boundaries in metals are generally considered as the source of the above problems but we present a diverse result. This study introduces an ultra-high proportion of grain boundaries on zinc electrodes through femtosecond laser bombardment to enhance stability of zinc metal/electrolyte interface. The ultra-high proportion of grain boundaries promotes the homogenization of zinc growth potential, to achieve uniform nucleation and growth, thereby suppressing dendrite formation. Additionally, the abundant active sites mitigate the side reactions during the electrochemical process. Consequently, the 15â µm Fs-Zn||MnO2 pouch cell achieves an energy density of 249.4â Wh kg-1 and operates for over 60 cycles at a depth-of-discharge of 23 %. The recognition of the favorable influence exerted by UP-GBs paves a new way for other metal batteries.
RESUMO
In a previous study, we observed that (E)-2-hexenal stimulated systemic resistance against B. cinerea in tomato plants. However, the molecular mechanisms underlying (E)-2-hexenal-mediated regulation of systemic immunity against B. cinerea remained unclear. In the current study, the global mechanism underlying (E)-2-hexenal-meidated regulation of biotic stress tolerance in tomato was investigated using RNA-seq- and LC-MS/MS- integrated transcriptomic and proteomic analyses. Compared to control plants, (E)-2-hexenal-treated plants exhibited reduced susceptibility to B. cinerea, with a 50.51% decrease in lesion diameters. Meanwhile, (E)-2-hexenal vapor fumigation significantly increased total phenolic content and activities of various antioxidant enzymes peroxidase (POD), phenylalanine ammonia lyase (PAL), and lipoxygenase (LOX). A total of 233 differentially expressed genes (DEGs) and 400 differentially expressed proteins (DEPs), respectively, were identified. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that (E)-2-hexenal treatment markedly affected the expression of genes involved in multiple metabolic pathways, especially glutathione metabolism, phenylpropanoid biosynthesis, plant hormone signal transduction, and MAPK signaling pathway. Notably, proteomic analysis revealed modulation of the activities of several defense response proteins, such as pathogenesis-related (PR) proteins (Solyc02g031950.3.1, Solyc02g031920.4.1, and Solyc04g064870.3.1), peroxidases (Solyc06g050440.3.1, Solyc01g105070.3.1, Solyc01g015080.3.1, Solyc03g025380.3.1 and Solyc06g076630.3.1). Our results provide a comprehensive analysis of the effects of (E)-2-hexenal treatment on the transcriptome and proteome of tomato plants, which might be used as a reference in further studies on plant defense responses against pathogens.
Assuntos
Solanum lycopersicum , Transcriptoma , Resistência à Doença/genética , Cromatografia Líquida , Proteômica , Proteínas de Plantas/genética , Espectrometria de Massas em Tandem , Mecanismos de DefesaRESUMO
Despite the intensive research in room-temperature phosphorescent (RTP) polymers, the synthesis of RTP polymers with well-defined macromolecular structures and multiple functions remains a challenge. Herein, reversible deactivation radical polymerization was demonstrated to offer a gradient copolymer (GCP) architecture with controlled heterogeneities, which combines hard segment and flexible segment. The GCPs would self-assemble into a multiphase nanostructure, featuring tunable stretchability, excellent RTP performance, and intrinsic healability without compromising light emission under stretching. The mechanical performance is tunable on demand with elongation at break ranging from 5.0% to 221.7% and Young's modulus ranging from 0.5 to 225.0 MPa.
RESUMO
BACKGROUND: α-fetoprotein (AFP) response has been demonstrated as a biomarker for unresectable hepatocellular carcinoma (uHCC) patients receiving immunotherapy, but its definition is still unclear. This exploratory study investigated the AFP trajectory and clinical outcomes of receiving atezolizumab plus bevacizumab (Atez/Bev) therapy. METHODS: This secondary analysis used the Atez/Bev arm data of phase III IMbrave150 study to distinguish potential AFP changing rate trajectories through latent class trajectory models. The multivariable Cox models were applied to calculate adjusted hazard ratios (HRs) and 95% CIs for clinical outcomes. RESULTS: Three distinct trajectories were identified among the uHCC patients with 7 times (range, 3 to 28) of AFP measurements: low-stable (50.0%, n = 132), sharp-falling (13.3%, n = 35), and high-rising (36.7%, n = 97). Compared with the high-rising class, HRs of disease progression were 0.52 (95% CI: 0.39, 0.70) and 0.26 (95% CI: 0.16, 0.43) for the low-stable class and sharp-falling class, respectively. In contrast, HRs of death were 0.59 (95% CI: 0.40, 0.81) and 0.30 (95% CI: 0.16, 0.57) for the two groups after propensity score adjustment. Besides, AFP trajectories had the highest relative importance of each covariate to survival. DISCUSSION: There are three distinct AFP trajectories in uHCC patients receiving Atez/Bev, and it is an independent biomarker for clinical outcomes.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , alfa-Fetoproteínas , Bevacizumab/uso terapêutico , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológicoRESUMO
Multifunctional electronic skins (e-skins) that can sense various stimuli have demonstrated increasing potential in many fields. However, most e-skins are human-oriented that cannot work in hash environments such as high temperature, underwater, and corrosive chemicals, impairing their applications, especially in human-machine interfaces, intelligent machines, robotics, and so on. Inspired by the crack-shaped sensory organs of spiders, an environmentally robust and ultrasensitive multifunctional e-skin is developed. By developing a polyimide-based metal crack-localization strategy, the device has excellent environment adaptability since polyimide has high thermal stability and chemical durability. The localized cracked part serves as an ultrasensitive strain sensing unit, while the non-cracked serpentine part is solely responsible for temperature. Since the two units are made of the same material and process, the signals are decoupled easily. The proposed device is the first multifunctional e-skin that can be used in harsh environments, therefore is of great potential for both human and robot-oriented applications.
Assuntos
Robótica , Dispositivos Eletrônicos Vestíveis , Humanos , Pele , Atenção à Saúde , SensaçãoRESUMO
Flexible pressure sensors play an increasingly important role in a wide range of applications such as human health monitoring, soft robotics, and human-machine interfaces. To achieve a high sensitivity, a conventional approach is introducing microstructures to engineer the internal geometry of the sensor. However, this microengineering strategy requires the sensor's thickness to be typically at hundreds to thousands of microns level, impairing the sensor's conformability on surfaces with microscale roughness like human skin. In this manuscript, a nanoengineering strategy is pioneered that paves a path to resolve the conflicts between sensitivity and conformability. A dual-sacrificial-layer method is initiated that facilitates ease of fabrication and precise assembly of two functional nanomembranes to manufacture the thinnest resistive pressure sensor with a total thickness of ≈850 nm that achieves perfectly conformable contact to human skin. For the first time, the superior deformability of the nanothin electrode layer on a carbon nanotube conductive layer is utilized by the authors to achieve a superior sensitivity (92.11 kPa-1 ) and an ultralow detection limit (<0.8 Pa). This work offers a new strategy that is able to overcome a key bottleneck for current pressure sensors, therefore is of potential to inspire the research community for a new wave of breakthroughs.
RESUMO
The exopolysaccharide galactosaminogalactan (GAG) has been well characterized in Aspergilli, especially the human pathogen Aspergillus fumigatus. It has been found that a five-gene cluster is responsible for GAG biosynthesis in Aspergilli to mediate fungal adherence, biofilm formation, immunosuppression or induction of host immune defences. Herein, we report the presence of the conserved GAG biosynthetic gene cluster in the insect pathogenic fungus Metarhizium robertsii to mediate either similar or unique biological functions. Deletion of the gene cluster disabled fungal ability to produce GAG on germ tubes, mycelia and appressoria. Relative to the wild type strain, null mutant was impaired in topical infection but not injection of insect hosts. We found that GAG production by Metarhizium is partially acetylated and could mediate fungal adherence to hydrophobic insect cuticles, biofilm formation, and penetration of insect cuticles. In particular, it was first confirmed that this exopolymer is responsible for the formation of appressorium mucilage, the essential extracellular matrix formed along with the infection structure differentiation to mediate cell attachment and expression of cuticle degrading enzymes. In contrast to its production during A. fumigatus invasive growth, GAG is not produced on the Metarhizium cells harvested from insect hemocoels; however, the polymer can glue germ tubes into aggregates to form mycelium pellets in liquid culture. The results of this study unravel the biosynthesis and unique function of GAG in a fungal system apart from the aspergilli species.
Assuntos
Interações Hospedeiro-Parasita/fisiologia , Metarhizium/metabolismo , Metarhizium/patogenicidade , Polissacarídeos/metabolismo , Virulência/fisiologia , Animais , Drosophila melanogaster/parasitologia , Proteínas Fúngicas/metabolismo , Mariposas/parasitologiaRESUMO
In order to compensate the optical system bias, which is caused by the change of elevation angle and thermal gradient during the optical alignment of the telescope, a novel high stiffness micro-nano positioning hexapod platform with flexure hinges is proposed in this paper. The novel flexure hinge has a mechanical limit, and its equivalent model is established and analyzed. In addition, in order to speed up the solution process, a novel simplified inverse kinematic model is developed based on the rigid body kinematic theory. Then, an effective rigid-flexible coupling simulation system is built to verify the correctness and applicability of the inverse kinematic model. Finally, a systematic experimental test method and a statistical-based data analysis theory are proposed. The experimental results show that the resolution and repeatability of translation and rotation and lateral stiffness are as follows: 0.3 mm and 0.5 arc sec, ± 0.5 µm and ±0.5 arc sec, 131.6Nâ µm-1 and 133.0Nâ µm-1. The proposed hexapod platform can be used to correct the optical system bias of large-aperture telescopes.