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Among arthropod vectors, ticks transmit the most diverse human and animal pathogens, leading to an increasing number of new challenges worldwide. Here we sequenced and assembled high-quality genomes of six ixodid tick species and further resequenced 678 tick specimens to understand three key aspects of ticks: genetic diversity, population structure, and pathogen distribution. We explored the genetic basis common to ticks, including heme and hemoglobin digestion, iron metabolism, and reactive oxygen species, and unveiled for the first time that genetic structure and pathogen composition in different tick species are mainly shaped by ecological and geographic factors. We further identified species-specific determinants associated with different host ranges, life cycles, and distributions. The findings of this study are an invaluable resource for research and control of ticks and tick-borne diseases.
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Variação Genética/genética , Doenças Transmitidas por Carrapatos/microbiologia , Carrapatos/genética , Animais , Linhagem Celular , Vetores de Doenças , Especificidade de Hospedeiro/genéticaRESUMO
Adeno-associated virus (AAV) has emerged as a leading platform for in vivo gene therapy, particularly in ocular diseases. AAV-based therapies are characterized by low pathogenicity and broad tissue tropism and have demonstrated clinical success as exemplified by Luxturna being the first gene therapy to be approved by the U.S. Food and Drug Administration to treat RPE65-associated Leber congenital amaurosis (LCA). However, several challenges remain in the development of AAV-based gene therapies, including immune responses, limited cargo capacity, and the need for enhanced transduction efficiency, especially for intravitreal delivery to photoreceptors and retinal pigment epithelium (RPE) cells. This review explores the biology of AAVs in the context of gene therapy, innovations in capsid engineering, and clinical advancements in AAV-based ocular gene therapy. We highlight ongoing clinical trials targeting inherited retinal diseases and acquired conditions, discuss immune-related limitations, and examine novel strategies for enhancing AAV vector performance to address current barriers.
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The programmed self-assembly of patchy nanoparticles (NPs) through a bottom-up approach is an efficient strategy for producing highly organized materials with a predetermined architecture. Herein, we report the preparation of di- and trivalent silica NPs with polystyrene (PS)/poly(4-vinylbenzyl azide) (PVBA) patches and assemble them in a THF mixture by lowering the solvent quality. Silica-PS/PVBA colloidal hybrid clusters were synthesized through the seeded growth emulsion copolymerization of styrene and 4-vinylbenzyl azide (VBA) in varying ratios. Subsequently, macromolecules on silica NPs originating from the copolymerization of growing PS or PVBA chains with the surface-grafted MMS compatibilizer are engineered by fine-tuning of polymer compositions or adjustment of solvent qualities. Moreover, multistage silica regrowth of tripod and tetrapod allowed a fine control of the patch-to-particle size ratio ranging from 0.69 to 1.54. Intriguingly, patchy silica NPs (1-, 2-, 3-PSNs) rather than hybrid clusters are successfully used as templates for multistep regrowth experiments, leading to the formation of silica NPs with a new morphology and size controllable PVBA/PS patches. Last but not least, combined with mesoscale dynamics simulations, the self-assembly kinetics of 2-PSN and 3-PSN into linear colloidal polymers and honeycomb-like lattices are studied. This work paves a new avenue for constructing colloidal polymers with a well-defined sequence and colloidal crystals with a predetermined architecture.
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Identifying ideal thermoelectric materials presents a formidable challenge due to the intricate coupling relationship between thermal conductivity and power factor. Here, based on first-principles calculations, along with self-consistent phonon theory and the Boltzmann transport equation, we theoretically investigate the thermoelectric properties of alkali metal phosphides M3P (M = Na and K). The evident 'avoided crossing' phenomenon indicates the phonon glass behavior of M3P (M = Na and K). Due to the strong lattice anharmonicity induced by alkali metal elements, accounting for quartic anharmonic corrections, the lattice thermal conductivities of Na3P and K3P at room temperature are merely 0.25 and 0.12 W m-1 K-1, respectively. Furthermore, the high degeneracy and 'pudding-mold-type' band structure lead to high p-type PF in M3P (M = Na and K). At 300 K, the p-type power factors (PF) of Na3P and K3P can reach 3.90 and 0.80 mW mK-2, respectively. The combination of ultralow κL and high PF leads to excellent thermoelectric figure of merit (ZT) values of 1.70 (3.38) and 1.18 (2.13) for p-type Na3P and K3P under optimal doping concentration at 300 K (500 K), respectively, surpassing traditional thermoelectric materials. These findings demonstrate that M3P (M = Na and K) exhibits behavior similar to phonon-glass electron crystals, thereby indicating a direction for the search for high-performance thermoelectric materials.
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Guiding and dynamically modulating topological defects are critical challenges in defect engineering of liquid crystals. Here, we employ molecular dynamics simulations to investigate the transition dynamics and relative kinetic stability of defect patterns in two-dimensional nematic Gay-Berne liquid crystals confined within rectangular geometries. We observe the formation of various defect patterns including long-axis, diagonal, X-shaped, composite, and bend configurations under different confinement conditions. The competition between boundary effects and the uniformity of nematic orientation induces the continuous realignment of liquid crystal molecules, facilitating the spatially continuous transformation of defect patterns over time. This transition involves changes in both defect types and their locations, typically initiating from defect regions. Furthermore, we demonstrate that the relative stability of these defect patterns can be effectively controlled by adjusting confinement parameters and external field conditions. Our findings provide fundamental insights into the transition kinetics of defect patterns in confined nematic liquid crystals, thereby enhancing our ability to manipulate topological defects for advanced applications.
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KEY MESSAGE: CsDGAT1A and CsDGAT2D play a positive regulatory role in cucumber's response to low-temperature stress and positively regulate the synthesis of triacylglycerol (TAG). Triacylglycerol (TAG), a highly abundant and significant organic compound in plants, plays crucial roles in plant growth, development, and stress responses. The final acetylation step of TAG synthesis is catalyzed by diacylglycerol acyltransferases (DGATs). However, the involvement of DGATs in cucumber's low-temperature stress response remains unexplored. This study focused on two DGAT genes, CsDGAT1A and CsDGAT2D, investigating their function in enhancing cucumber's low-temperature stress tolerance. Our results revealed that both proteins were the members of the diacylglycerol acyltransferase family and were predominantly localized in the endoplasmic reticulum. Functional analysis demonstrated that transient silencing of CsDGAT1A and CsDGAT2D significantly compromised cucumber's low-temperature stress tolerance, whereas transient overexpression enhanced it. Furthermore, the TAG content quantification indicated that CsDGAT1A and CsDGAT2D promoted TAG accumulation. In conclusion, this study elucidates the lipid metabolism mechanism in cucumber's low-temperature stress response and offers valuable insights for the cultivation of cold-tolerant cucumber plants.
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Temperatura Baixa , Cucumis sativus , Diacilglicerol O-Aciltransferase , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas , Triglicerídeos , Cucumis sativus/genética , Cucumis sativus/enzimologia , Triglicerídeos/metabolismo , Triglicerídeos/biossíntese , Diacilglicerol O-Aciltransferase/genética , Diacilglicerol O-Aciltransferase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Estresse Fisiológico/genética , Resposta ao Choque Frio/genéticaRESUMO
OBJECTIVE: Pulmonary infection is one of the leading causes of death in patients with ANCA-associated vasculitis (AAV). It is sometimes difficult to differentiate pulmonary infection from pulmonary involvement of vasculitis in AAV patients. Fiberoptic bronchoscopy and bronchoalveolar lavage fluid (BALF) assays are useful diagnostic methods. In addition to conventional microbiological tests (CMTs), metagenomic next-generation sequencing (mNGS) facilitates rapid and sensitive detection of various pathogens. The current study aimed to evaluate the advantages of additional BALF mNGS in the management of pulmonary infection in AAV patients. METHODS: 27 patients with active AAV and suspected pulmonary infection whose BALF samples were tested by mNGS and CMTs and 17 active AAV patients whose BALF were tested by CMTs alone were retrospectively recruited. The results of microbiological tests, and adjustments of treatment following BALF mNGS, were described. The durations of antimicrobial treatment and in-hospital mortality in patients were compared. RESULTS: Among the 27 patients whose BALF samples were tested by mNGS, 25.9% of patients did not have evidence of pathogenic microorganism in their BALF samples, 55.6% had polymicrobial infections, including bacteria, fungi and viruses. Of these 27 patients, 40.7% did not have evidence of pathogenic microorganism in their BALF or serum samples according to CMTs. Patients in the BALF mNGS/CMT group received a significantly shorter duration of antibacterial and total antimicrobial treatment than patients in the CMT alone group (17.3 ± 14.7 vs. 27.9 ± 19.0 days, P = 0.044; 18.9 ± 15.0 vs. 29.5 ± 17.7 days, P = 0.040, respectively). Fewer patients in the BALF mNGS/CMT group died than in the CMT alone group (4/27 vs. 7/17, P = 0.049). CONCLUSION: Compared with CMT alone, additional mNGS tests may shorten the duration of antimicrobial treatment and possibly decrease death from severe infection by providing precise and quick diagnosis of infection.
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Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos , Líquido da Lavagem Broncoalveolar , Sequenciamento de Nucleotídeos em Larga Escala , Metagenômica , Humanos , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/diagnóstico , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/tratamento farmacológico , Masculino , Feminino , Pessoa de Meia-Idade , Líquido da Lavagem Broncoalveolar/microbiologia , Estudos Retrospectivos , Idoso , Metagenômica/métodos , Broncoscopia , Mortalidade Hospitalar , Infecções Respiratórias/microbiologia , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/tratamento farmacológico , AdultoRESUMO
If pharmaceutical wastewater is not managed effectively, the presence of residual antibiotics will result in significant environmental contamination. In addition, inadequate utilization of agricultural waste represents a squandering of resources. The objective of this research was to assess the efficacy of iron-doped biochar (Fe-BC) derived from peanut shells in degrading high concentrations of Tetracycline (TC) wastewater through activated peroxymonosulfate. Fe-BC demonstrated significant efficacy, achieving a removal efficiency of 87.5% for TC within 60 min without the need to adjust the initial pH (20 mg/L TC, 2 mM PMS, 0.5 g/L catalyst). The degradation mechanism of TC in this system involved a dual action, namely Reactive Oxygen Species (ROS) and electron transfer. The primary active sites were the Fe species, which facilitated the generation of SO4â¢-, â¢OH, O2â¢-, and 1O2. The presence of Fe species and the C=C structure in the Fe-BC catalyst support the electron transfer. Degradation pathways were elucidated through the identification of intermediate products and calculation of the Fukui index. The Toxicity Estimator Software Tool (T.E.S.T.) suggested that the intermediates exhibited lower levels of toxicity. Furthermore, the system exhibited exceptional capabilities in real water and circulation experiments, offering significant economic advantages. This investigation provides an efficient strategy for resource recycling and the treatment of high-concentration antibiotic wastewater.
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Carvão Vegetal , Ferro , Espécies Reativas de Oxigênio , Tetraciclina , Águas Residuárias , Tetraciclina/química , Carvão Vegetal/química , Espécies Reativas de Oxigênio/química , Águas Residuárias/química , Ferro/química , Poluentes Químicos da Água/química , Peróxidos/química , Transporte de ElétronsRESUMO
Circularly polarized luminescence (CPL) has numerous applications in optical data storage, quantum computing, bioresponsive imaging, liquid crystal displays, and backlights in three-dimensional (3D) displays. In addition to their competitive optical properties, carbon dots (CDs) benefit from simple and low-cost preparation, facile post-modification, and excellent resistance to photo- and chemical bleaching after carbonization. Combining the superior optical performance with polarization peculiarities through hierarchical structure engineering is imperative for the development of CDs. In this study, hydrophobic interactions of aromatic ligands, which participate in the surface-ligand post-modification process on the ground-state chiral carbon core, are employed to drive the oriented assembly. Furthermore, the residual chiral amides on CDs form multiple hydrogen bonds during gradual aggregation, causing the assembled materials to form an asymmetric bending structure. Superficial ligands interfere with the optical dynamics of the exciton radiation transition and stabilize the excited state of the assembled materials to achieve a circularly polarized signal. The linkage ligands overcome the frequent aggregation-induced quenching phenomenon that present difficulties in conventional CDs, facilitate the assembly of self-supporting films, and improve chiral optical expression. The full-color and white CPL are manipulated by simply adjusting the functional groups of the ligands, which also illustrates the versatility of the post-modification strategy. Finally, large chiral flexible films and multicolor chiral light-emitting diodes based on the stable chiral powder phosphors were constructed, thereby providing feasible materials and technical support for flexible 3D displays.
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Clostridioides difficile infection (CDI) causes severe diarrhea and colitis, leading to significant morbidity, mortality, and high medical costs worldwide. Oral vancomycin, a first-line treatment for CDI, is associated with a high risk of recurrence, necessitating novel therapies for primary and recurrent CDI. A novel small-molecule compound, CDBN-YGXZ, was synthesized by modifying the benzene ring of nitazoxanide with lauric acid. The mechanism of action of CDBN-YGXZ was validated using a pyruvate:ferredoxin/flavodoxin oxidoreductase (PFOR) inhibition assay. The efficacy of CDBN-YGXZ was evaluated using the MIC test and CDI infection model in mice and hamsters. Furthermore, metagenomics was used to reveal the underlying reasons for the effective reduction or prevention of CDI after CDBN-YGXZ treatment. The inhibitory activity against PFOR induced by CDBN-YGXZ. MIC tests showed that the in vitro activity of CDBN-YGXZ against C. difficile ranging from 0.1 to 1.5 µg/mL. In the mouse and hamster CDI models, CDBN-YGXZ provided protection during both treatment and relapse, while vancomycin treatment resulted in severe relapse and significant clinical scores. Compared with global effects on the indigenous gut microbiota induced by vancomycin, CDBN-YGXZ treatment had a mild influence on gut microbes, thus resulting in the disappearance or reduction of CDI recurrence. CDBN-YGXZ displayed potent activity against C. difficile in vitro and in vivo, reducing or preventing relapse in infected animals, which could merit further development as a potential drug candidate for treating CDI.
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Clostridioides difficile , Infecções por Clostridium , Cricetinae , Animais , Camundongos , Vancomicina/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/prevenção & controle , RecidivaRESUMO
BACKGROUND: The purpose of this study was to investigate the role of hsa_circRNA_102051 in colorectal cancer (CRC) and its effect on the stemness of tumor cells. METHODS: CircRNA microarray was under analysis to screen differentially expressed novel circRNAs in the pathology of CRC. Quantitative real-time PCR was used to detect the relative RNA expression in CRC cells and samples. The effects of hsa_circRNA_102051 on biological functions in CRC cells were accessed both in vitro and in vivo. FISH, RIP and luciferase reporter assay were conducted to confirm the regulatory correlations between hsa_circRNA_102051 and miR-203a, as well as miR-203a and BPTF. Xenograft models were applied to further verify the impacts and fluctuations of hsa_circRNA_102051/miR-203a/BPTF. Moreover, the mechanism how hsa_circRNA_102051 affected the Notch signals was also elucidated. RESULTS: Hsa_circRNA_102051 was up-regulated in CRC tissues and cell lines, capable to promote the growth and invasion of CRC. In addition, hsa_circRNA_102051 could enhance stemness of CRC cells. BPTF was identified as downstream factors of hsa_circRNA_102051, and miR-203a was determined directly targeting both hsa_circRNA_102051 and BPTF as an intermediate regulator. Hsa_circRNA_102051 in CRC could block miR-203a expression, and subsequently activated BPTF. Hsa_circRNA_102051/miR-203a/BPTF axis modulated stemness of CRC cells by affecting Notch pathway. CONCLUSIONS: Our findings provided new clues that hsa_circRNA_102051 might be a potential predictive or prognostic factor in CRC, which induced the fluctuation of downstream miR-203a/BPTF, and subsequently influenced tumor growth, activities and stemness. Thereinto, the Notch signals were also involved. Hence, the hsa_circRNA_102051/miR-203a/BPTF axis could be further explored as a therapeutic target for anti-metastatic therapy in CRC patients.
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A liposome-based micromotor system that utilizes regional enzymatic conversion and gas generation to achieve directional motion in water is presented. Constituted mainly of a low-melting lipid and a high-melting lipid together with cholesterol, these liposomes maintain stable Janus configuration at room temperature as a result of lipid liquid-liquid phase separation. Local placement of enzymes such as horseradish peroxidase is realized via affinity binding between avidin and biotin, the latter as a lipid conjugate sorted specifically into one domain of these Janus liposomes as a minor component. In the presence of the substrate, hydrogen peroxide, these enzyme-decorated Janus liposomes undergo directional motion, yielding velocities exceeding thermal diffusion by three folds in some cases. Experimental details on liposome size control, motor assembly, and substrate distribution are presented; effects of key experimental factors on liposome motion, such as substrate concentration and liposome Janus ratio, are also examined. This work thus provides a viable approach to building asymmetrical lipid-assembled, enzyme-attached colloids and, in addition, stresses the importance of asymmetry in achieving particle directional motion.
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Biotina , Lipossomos , Lipossomos/química , Biotina/química , Avidina/química , Movimento (Física) , Lipídeos/químicaRESUMO
The formation and transformation of defects in confined liquid crystals are fascinating fundamental problems in soft matter. Here, we use molecular dynamics (MD) simulations to study ellipsoidal liquid crystals (LCs) confined in a spherical cavity, which significantly affects the orientation and translation of LC molecules near the surface. The liquid-crystal droplet can present the isotropic to smectic-B phase transition through the smectic-A phase, as the number density of the LC molecules increases. We further find the change of LC structure from bipolar to watermelon-striped during the phase transition from smectic-A (SmA) to smectic-B (SmB) phases. Our results reveal the transition from bipolar defects to the inhomogeneous structures with the coexistence of nematic and smectic phases in smectic liquid-crystal droplets. We also study the influence of the sphere size in the range of 10σ0 ≤ Rsphere ≤ 50σ0 on the structural inhomogeneities. It shows a weak dependence on the sphere size. We further focus on how the structures can be affected by the interaction strength εGB-LJ. Interestingly, we find the watermelon-striped structure can be changed into a configuration with four defects at the vertices of a tetrahedron upon increasing the interaction strength. The liquid crystals at a strong interaction strength of εGB-LJ = 10.0ε0 show the two-dimensional nematic phase at the surface. We further present an explanation for the origin of the striped-pattern formation. Our results highlight the potential for using confinement to control these defects and their associated nanostructural heterogeneity.
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We report an efficient alkyl transfer strategy for the direct ß-alkylation of chalcones using commercially available alkyl bromides as alkyl reagents. In this transformation, the ortho-phosphanyl substituent in the chalcones is crucial for controlling their reactivity and selectivity. It also serves as a reliable alkyl transfer shuttle to transform electrophilic alkyl bromides into nucleophilic alkyl species in the form of quaternary phosphonium salts and transfer the alkyl group effectively to the ß-position of the chalcones. This alkyl transfer strategy can be further extended to the alkenylation of ortho-phosphanyl benzaldehydes to assemble functionalized polyenes.
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Chalconas , Brometos , Catálise , Sais , AlquilaçãoRESUMO
Small yellow croaker (Larimichthys polyactis) is one of the most economically important marine fishery species. L. polyactis aquaculture has experienced stress response and the frequent occurrence of diseases, bringing huge losses to the aquaculture industry. Little is known about the regulation mechanism of heat stress response in L. polyactis. In this study, to provide an overview of the heat-tolerance mechanism of L. polyactis, the transcriptome and proteome of the liver of L. polyactis on the 6 h after high temperature (32 °C) treatment were analyzed using Illumina HiSeq 4000 platform and isobaric tag for relative and absolute quantitation (iTRAQ). A total of 3700 upregulated and 1628 downregulated genes (differentially expressed genes, DEGs) were identified after heat stress in L. polyactis. Also, 198 differentially expressed proteins (DEPs), including 117 upregulated and 81 downregulated proteins, were identified. Integrative analysis revealed that 72 genes were significantly differentially expressed at transcriptome and protein levels. Functional analysis showed that arginine biosynthesis, tyrosine metabolism, pentose phosphate pathway, starch and sucrose metabolism, and protein processing in the endoplasmic reticulum were the main pathways responding to heat stress. Among the pathways, protein processing in the endoplasmic reticulum was enriched by most DEGs/DEPs, which suggests that this pathway may play a more important role in the heat stress response. Further insights into the pathway revealed that transcripts and proteins, especially HSPs and PDIs, were differentially expressed in response to heat stress. These findings contribute to existing data describing the fish response to heat stress and provide information about protein levels, which are of great significance to a deeper understanding of the heat stress responding regulation mechanism in L. polyactis and other fish species.
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Perciformes , Transcriptoma , Animais , Proteoma/genética , Resposta ao Choque Térmico , Fígado/metabolismo , Perciformes/genética , Perfilação da Expressão Gênica/veterináriaRESUMO
With the widespread use of sulfonamide antibiotics (SAs), SAs are detected as residues in aquatic environments, posing a serious threat to human life and safety. Because of their high water solubility, fast transmission rate, and strong antibacterial properties, the safe disposal of SAs has become a key constraint for water quality assurance. Therefore, an ultrasound (US)-assisted zero-valent iron (ZVI)/persulfate (PS) system was proposed to explore the rapid and effective degradation of SAs. Comparative experiments were performed to study the removal of sulfadiazine (SDZ) by US, ZVI, PS, US/ZVI, US/PS, ZVI/PS, and US-ZVI/PS systems, respectively. Experimental results indicated that the highest removal efficiency of SDZ was ahieved in US-ZVI/PS system (97.4%), which were 2-44 times higher than that in other systems. Furthermore, the degradation efficiency of five typical SAs was achieved over 95%, demonstrating the effectiveness of the US ZVI/PS system for SAs removal. Also, quantum chemical computations for potential reactive sites of SAs and intermediate product detection by HPLCâMS/MS were performed. The radical attack on active sites of SAs, such as N atom (number 7), was the main reason for SAs removal in US-ZVI/PS system. Besides, the common degradation pathways of six typical SAs were defined as S-N bond cleavage, C-N bond cleavage, benzene ring hydroxylation, aniline oxidation, and R substituent oxidation. Interestingly, the unique pathway of "SO2 group extraction" was observed in the degradation of six-membered ring SAs. Therefore, the US-ZVI/PS system is a promising and cost-effective method for the removal of SAs and other refractory pollutants.
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Antibacterianos , Espectrometria de Massas em Tandem , Humanos , Sulfanilamida , Sulfadiazina , Sulfonamidas , FerroRESUMO
Integration of hexagonal boron nitride (h-BN) with plasmonic nanostructures that possess nanoscale field confinement will enable unusual properties; hence, the manipulation and understanding of the light interactions are highly desirable. Here, we demonstrate the surface plasmonic coupling of Au nanoparticles (ANPs) with ultrathin h-BN nanosheets (BNNS) in nonspecific nanocomposites leading to a great enhancement of the Raman signal of E2g in both experimental and theoretical manner. The nanocomposites were fabricated from liquid-exfoliated atomically thin BNNS and diblock copolymer-based ANPs with excellent dispersion through a self-assembly approach. By precisely varying the size of ANPs from 3 to 9 nm, the Raman signal of BNNS was improved from 1.7 to 71. In addition, the underlying mechanism has been explored from the aspects of electromagnetic field coupling strength between the localized surface plasmons excited from ANPs and the surrounding dielectric h-BN layers, as well as the charge transfer at the BNNS/ANPs interfaces. Moreover, we also demonstrate its capability to detect dye molecules as a surface enhanced Raman scattering (SERS) substrate. This work provides a basis for the self-assembly of BNNS hierarchical nanocomposites allowing for plasmon-mediated modulation of their optoelectronic properties, thereby showing the great potential not only in the field of SERS but also in large-scale h-BN-based plasmonic devices.
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Confined liquid crystals (LCs) exhibit complex and intriguing structures, which are fascinating fundamental problems in soft matter. The helical structure of cylindrical cavities is of great importance in LC studies, particularly for their application in optical devices. In this study, we employ molecular dynamics simulations to explore the behavior of achiral smectic-B LCs confined in narrow cylindrical cavities, where geometric frustration plays an important role. By increasing the cylinder size, LCs exhibit a transition from multi-helical to layered structures. Notably, we observe two stable structures, namely the helical structure and the layered structure, at moderate cylinder size. We also investigate the effects of the arrangement of cylindrical wall particles (hexagonal or square array) and anchoring strength on the LC structure. Our findings reveal that both the hexagonal array and strong anchoring strength promote the formation of helical structures. Our study provides novel insights into the confinement physics of LCs and highlights the potential for achieving helical structures in achiral LCs, which will expand the future applications of LCs.
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Normally, defects in two-dimensional, circular, confined liquid crystals can be classified into four types based on the position of singularities formed by liquid crystal molecules, i.e., the singularities located inside the circle, at the boundary, outside the circle, and outside the circle at infinity. However, it is considered difficult for small aspect ratio liquid crystals to generate all these four types of defects. In this study, we use molecular dynamics simulation to investigate the defect formed in Gay-Berne, ellipsoidal liquid crystals, with small aspect ratios confined in a circular cavity. As expected, we only find two types of defects (inside the circle and at the boundary) in circular, confined, Gay-Berne ellipsoids under static conditions at various densities, aspect ratios, and interactions between the wall and liquid crystals. However, when introducing an external field to the system, four types of defects can be observed. With increasing the strength of the external field, the singularities in the circular, confined system change from the inside to the boundary and the outside, and the farthest position that the singularities can reach depends on the strength of the external field. We further introduce an alternating, triangular wave, external field to the system to check if we can observe the transformation of different defects within an oscillating period. We find that the position of the singularities greatly depends on the oscillating intensity and oscillating period. By changing the oscillating intensity and oscillating period of the external field, the defect types can be adjusted, and the transformation between different defects can be easily observed. This provides a feasible way to modulate liquid crystal defects and investigate the transformation between different defects.
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Pest management has long been a critical aspect of crop protection. Insect behavior is of great research value as an important indicator for assessing insect characteristics. Currently, insect behavior research is increasingly based on the quantification of behavior. Traditional manual observation and analysis methods can no longer meet the requirements of data volume and observation time. In this paper, we propose a method based on region localization combined with an improved 3D convolutional neural network for six grooming behaviors of Bactrocera minax: head grooming, foreleg grooming, fore-mid leg grooming, mid-hind leg grooming, hind leg grooming, and wing grooming. The overall recognition accuracy reached 93.46%. We compared the results obtained from the detection model with manual observations; the average difference was about 12%. This shows that the model reached a level close to manual observation. Additionally, recognition time using this method is only one-third of that required for manual observation, making it suitable for real-time detection needs. Experimental data demonstrate that this method effectively eliminates the interference caused by the walking behavior of Bactrocera minax, enabling efficient and automated detection of grooming behavior. Consequently, it offers a convenient means of studying pest characteristics in the field of crop protection.