Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nat Commun ; 15(1): 4554, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38811587

RESUMO

High-entropy alloys (HEAs) provide new research avenues for alloy combinations in the periodic table, opening numerous possibilities in novel-alloy applications. However, their electrical characteristics have been relatively underexplored. The challenge in establishing an HEA electrical conductivity model lies in the changes in electronic characteristics caused by lattice distortion and complexity of nanostructures. Here we show a low-frequency electrical conductivity model for the Nb-Mo-Ta-W HEA system. The cocktail effect is found to explain trends in electrical-conductivity changes in HEAs, while the magnitude of the reduction is understood by the calculated plasma frequency, free electron density, and measured relaxation time by terahertz spectroscopy. As a result, the refractory HEA Nb15Mo35Ta15W35 thin film exhibits both high hardness and excellent conductivity. This combination of Nb15Mo35Ta15W35 makes it suitable for applications in atomic force microscopy probe coating, significantly improving their wear resistance and atomic-scale image resolution.

2.
Rev Sci Instrum ; 95(1)2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38214591

RESUMO

An economical and stable single-shot pulse picker design without dispersion, nonlinear effect, and limitation on wavelength is proposed. This design is composed of a periodic pulse blocker (PPB), a control unit, and a mechanical shutter. It has successfully been applied to the commercial high-fluence femtosecond laser with 11-mm beam diameter, 2-mJ pulse energy, and 1-kHz repetition rate. Significantly, by incorporating commercial optical choppers equipped with custom-designed chopper blades in the PPB, this design can accommodate lasers with fluences reaching 610 mJ/cm2 and the standard 1 kHz repetition rate typical of high-fluence lasers. Furthermore, the proposed design provides a cost-effective substitute compared to using electro-optic modulators or acousto-optic modulators.

3.
Phys Chem Chem Phys ; 24(21): 12816-12826, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35608151

RESUMO

Borophene (B), with remarkably unique chemical binding in its crystallographic structural phases including anisotropic structures, theoretically has high Young's modulus and thermal conductivity. Moreover, it is metallic in nature, and has recently joined the family of two-dimensional (2D) materials and is poised to be employed in flexible hetero-layered devices and sensors in fast electronic gadgets and excitonic devices. Interfacial coupling helps individual atomic sheets synergistically work in tandem, and is very crucial in controllable functionality. Most of the microscopic and spectroscopic scans reveal surface information; however, information regarding interfacial coupling is difficult to obtain. Electronic signatures of dynamic inter-layer coupling in B/boron nitride (BN) and B/molybdenum disulfide (MoS2) have been detected in the form of distinct peaks in differential current signals obtained from scanning tunneling spectroscopy (STS) and conducting atomic force microscopy (CAFM). These unique sets of observed peaks represent interfacial coupling quantum states. The peaks in the electronic density of states (DOS) obtained via density functional theory (DFT) band structure calculations matched well with the electronic signatures of coupling quantum states. In our calculations, we found that the DOS peak evolves when the component layers are brought to compromised distances. While B/BN exhibits green sensitivity indicating mid-gap formation, B/MoS2 bestows red sensitivity indicating band-gap excitation of MoS2. Molecular detection of methylene blue (MB) based on surface-enhanced Raman spectroscopy (SERS) was carried out with borophene-based hetero-layered stacks as molecular anchoring platforms.

4.
Mol Plant Microbe Interact ; 33(2): 256-271, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31809253

RESUMO

Rhizosphere interactions between microorganisms and plants have great influence on plant health. Bacillus cereus C1L, an induced systemic resistance (ISR)-eliciting rhizobacterium from Lilium formosanum, can protect monocot and dicot plants from disease challenges. To identify the ISR-involved bacterial genes, the systemic protection effect of transposon-tagged mutants of B. cereus C1L against southern corn leaf blight (SCLB) was surveyed, and a mutant of the ptsG gene encoding glucose-specific permease of the phosphotransferase system was severely impaired in the abilities of disease suppression and root colonization. The ptsG mutant lost the preferential utilization of glucose and showed reduction of glucose-assisted growth in minimal medium. A promoter-based reporter assay revealed that ptsG expression could be activated by certain sugar constituents of maize root exudates, among which B. cereus C1L exhibited the highest chemotactic response toward glucose, whereas neither of them could attract the ptsG mutant. Additionally, ptsG deficiency almost completely abolished glucose uptake of B. cereus C1L. Metabolite analysis indicated that the lack of ptsG undermined glucose-induced accumulation of acetoin and 2,3-butanediol in B. cereus C1L, both eliciting maize ISR against SCLB. Pretreatments with B. cereus C1L, ptsG mutant, acetoin, and 2,3-butanediol enhanced defense-related reactive oxygen species accumulation and callose deposition at different levels that were positively correlated to their ISR-eliciting activities. Thus, glucose uptake-mediating ptsG participates in ISR elicitation by endowing B. cereus C1L with the full capacities for root colonization and beneficial glucose metabolite production, providing a clue regarding how ISR-mediating rhizobacteria create a mutually beneficial relationship with various plant species.


Assuntos
Resistência à Doença , Interações Hospedeiro-Patógeno , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato , Plantas , Bacillus cereus/enzimologia , Bacillus cereus/genética , Bacillus cereus/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Resistência à Doença/genética , Glucose/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Mutação , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/genética , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/metabolismo , Plantas/imunologia , Plantas/microbiologia
5.
Biochem Biophys Res Commun ; 473(4): 808-813, 2016 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-27040766

RESUMO

Bispecific antibodies (bsAbs) are second generation antibodies for therapeutic application in immunotherapy. One of the major strategies of the bsAb platform is the recruitment of immune effector T cells by incorporating an anti-CD3 domain. A bispecific T-cell engager (BiTE), with one end having an affinity for CD3 and the other end with affinity for CD19, has been approved in the US and Europe for the treatment of acute lymphoblastic leukemia. However, due to their small size and lack of Fc region, these single-chain variable fragment (scFv) bsAbs have short half-lives in vivo. Additionally, poor solubility, structural instability, and low production yields have also become major challenges in the bulk production process. To overcome these challenges, we have engineered a tetravalent bsAb with bivalent binding specificity for the CD20 and CD3 antigen in an immunoglobulin G (IgG) format. The fusion of the anti-CD3 scFvs to the CD20 antibody via a linker-hinge domain (LHD) results in improved antibody stabilization and properties. Here we demonstrate this antibody's highly efficient cancer cell elimination in a dose-dependent manner in a CD20-expressing B lymphoblastoid cell line in vitro. Our data suggest the potential clinical application of this bsAb for the treatment of CD20-expressing B cell malignancies.


Assuntos
Anticorpos Monoclonais/administração & dosagem , Antígenos CD20/imunologia , Complexo CD3/imunologia , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/imunologia , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Desenho de Fármacos , Estabilidade de Medicamentos , Humanos , Células Jurkat , Linfoma de Células B/patologia , Engenharia de Proteínas , Resultado do Tratamento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA