Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
1.
Micromachines (Basel) ; 15(9)2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39337820

RESUMO

Two-hierarchical nanostructures, characterized by two distinct configurations along the height direction, exhibit immense potential for applications in various fields due to their significantly enhanced controllable degree compared to single-order structures. However, due to the limitations imposed by planar technology, the realization of two-hierarchical nanostructures encounters huge challenges. In this work, we developed a one-step etching method based on inductively coupled plasma reactive ion etching for two-hierarchical nanostructures. Thanks to the shrinking effect of the Cr mask and the generation of a passivation layer during etching, the target materials experienced two different states from vertical etching to shrink etching. Consequently, the achieved two-hierarchical nanostructure configuration features a cross-section of an upper triangle and a lower rectangle, showing higher controllable degrees compared to the one-order ones. Both the mask pattern and etching parameters play crucial roles, by which two-hierarchical structures with diversiform shapes can be constructed controllably. This method for two-hierarchical nanostructures offers advantages including excellent control over structural properties, high processing efficiency, uniformity across large areas, and universality in materials. This developed strategy not only presents a simple and rapid nanofabrication platform for realizing optoelectronic devices, but also provides innovative ideas for designing the next generation of high-performance devices.

2.
Eur J Med Res ; 28(1): 470, 2023 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-37898776

RESUMO

BACKGROUND: Insulin resistance (IR) had been reported to be associated with age; however, few studies have explored the association between IR and biological age (BA). The HOMA-IR value is a useful indicator of the extent of IR. This cross-sectional study is to explore the relationship between HOMA-IR and BA/advanced aging in the US population. METHODS: This study is a cross-sectional analysis of National Health and Nutrition Examination Survey (NHANES) data. The survey comprised 12,266 people from the NHANES, and their full HOMA-IR data as well as BA data were extracted. Four multiple linear regressions were performed to analyze the association between HOMA-IR and BA, and four multiple logistic regression models were performed to analyze the association between HOMA-IR and advanced aging. In addition, trend tests and stratified analysis were performed and smoothed fitted curves were plotted to test the robustness of the results. RESULTS: HOMA-IR was positively correlated with BA [ß: 0.51 (0.39, 0.63)], and it was the same to advanced aging [OR: 1.05 (1.02, 1.07)], and both showed a monotonically increasing trend. The trend tests showed that the results were stable (all P for trend < 0.0001). The smoothed fitted curves showed that there were non-linear relationships between HOMA-IR and BA/advanced aging. And the stratified analysis indicated that the relationship between HOMA-IR and BA/advanced aging remained robust in all subgroups. CONCLUSION: The study suggested that HOMA-IR is positively correlated with BA and advanced aging in the US adult population, with a monotonic upward trend. This is a new finding to reveal the relationship between HOMA-IR and age from new standpoint of BA rather than chronological age (CA). And it may contribute to a better understanding of human health aging and may aid future research in this field.


Assuntos
Resistência à Insulina , Adulto , Humanos , Estudos Transversais , Inquéritos Nutricionais , Envelhecimento , Inquéritos e Questionários
3.
Micromachines (Basel) ; 13(6)2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35744470

RESUMO

Three-dimensional (3D) nanostructures have attracted widespread attention in physics, chemistry, engineering sciences, and biology devices due to excellent functionalities which planar nanostructures cannot achieve. However, the fabrication of 3D nanostructures is still challenging at present. Reliable fabrication, improved controllability, and multifunction integration are desired for further applications in commercial devices. In this review, a powerful fabrication method to realize 3D nanostructures is introduced and reviewed thoroughly, which is based on atomic layer deposition assisted 3D assembly through various sacrificial templates. The aim of this review is to provide a comprehensive overview of 3D nanofabrication based on atomic layer assembly (ALA) in multifarious sacrificial templates for 3D nanostructures and to present recent advancements, with the ultimate aim to further unlock more potential of this method for nanodevice applications.

4.
Cancer Invest ; 39(5): 369-378, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33886387

RESUMO

OBJECTIVE: To evaluate the efficacy and safety of cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors combined with endocrine therapy (ET) for hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER-2-) advanced breast cancer (ABC) patients. METHODS: We searched clinical trials of CDK4/6 inhibitors combined with ET and calculated the clinical outcomes. RESULTS: HR+/HER-2- ABC patients treated with CDK4/6 inhibitors combined with ET had significantly prolonged progression-free survival (PFS) and improved objective response rate (ORR) and clinical benefit rate (CBR). CONCLUSIONS: CDK4/6 inhibitors combined with ET can bring more clinical benefits to ABC patients, and the safety profile is acceptable.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Receptores de Estrogênio/uso terapêutico , Receptores de Progesterona/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Feminino , Humanos
5.
Zookeys ; 996: 37-58, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33312045

RESUMO

In this study, four new dextral camaenid from China are reported, based on shell morphology, reproductive system anatomy, and molecular phylogenetic analyses: Camaena funingensis Zhou, Wang & Lin, sp. nov., Camaena gaolongensis Zhou, Wang & Lin, sp. nov., Camaena maguanensis Zhou, Wang & Hu, sp. nov., and Camaena yulinensis Zhou, Wang & Hu, sp. nov. Detailed descriptions of the morphological characteristics including shells and genitalia, DNA sequences, and living environments of the four new species are provided, with further comparisons with congeners.

6.
Integr Med Res ; 9(4): 100431, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32637314

RESUMO

BACKGROUND: The evidence of Acupuncture combined with speech rehabilitation training for post-stroke dysarthria is insufficient and there is no consensus on its efficacy. METHODS: We searched seven Chinese and English medicine databases for randomized controlled trials (RCTs) from their inception to November 2019. The primary outcome measure was the clinical response rate, assessed with the Frenchay Dysarthria Assessment (FDA) tool. We assessed risk of bias using the Cochrane risk-of-bias tool. We used GRADE to assess the certainty of evidence (CoE). RESULTS: Thirty studies were included in this systematic review, 23 of which were pooled in meta-analysis. Acupuncture combined with speech rehabilitation training is likely beneficial for was response rate (n = 1685; RR = 1.37; 95% CI [1.29, 1.46], P < 0.01, I 2 = 34%; 17 studies, low CoE) compared to speech rehabilitation treatment alone. CONCLUSION: The combination of acupuncture and speech rehabilitation training may improve total response rate of stroke patients with dysarthria. However, more RCTs with rigorous study design and validated outcome measures are needed to confirm the evidence.

7.
Nano Lett ; 19(7): 4551-4559, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31241975

RESUMO

With strong spin-orbit coupling (SOC), ultrathin two-dimensional (2D) transitional metal chalcogenides (TMDs) are predicted to exhibit weak antilocalization (WAL) effect at low temperatures. The observation of WAL effect in VSe2 is challenging due to the relative weak SOC and three-dimensional (3D) transport nature in thick VSe2. Here, we report on the observation of quasi-2D transport and WAL effect in sublimed-salt-assisted low-temperature chemical vapor deposition (CVD) grown few-layered high-quality VSe2 nanosheets. The WAL magnitudes in magnetoconductance can be perfectly fitted by the 2D Hikami-Larkin-Nagaoka (HLN) equation in the presence of strong SOC, by which the spin-orbit scattering length lSO and phase coherence length lϕ have been extracted. The phase coherence length lϕ shows a power law dependence with temperature, lϕ∼ T-1/2, revealing an electron-electron interaction-dominated dephasing mechanism. Such sublimed-salt-assisted growth of high-quality few-layered VSe2 and the observation of WAL pave the way for future spintronic and valleytronic applications.

8.
Nano Lett ; 19(6): 3432-3439, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-30608711

RESUMO

Controlling the spin angular momentum of light (or circular polarization state) plays a crucial role in the modern photonic applications such as optical communication, circular dichroism spectroscopy, and quantum information processing. However, the conventional approaches to manipulate the spin of light require naturally occurring chiral or birefringent materials of bulky sizes due to the weak light-matter interactions. Here we experimentally demonstrate an approach to implement spin-selective transmission in the infrared region based on chiral folded metasurfaces that are capable of transmitting one spin state of light while largely prohibiting the other. Due to the intrinsic chirality of the folded metasurface, a remarkable circular dichroism as large as 0.7 with the maximum transmittance exceeding 92% is experimentally demonstrated. The giant circular dichroism is interpreted within the framework of charge-current multipole expansion. Moreover, the intrinsic chirality can be readily controlled by manipulating the folding angle of the metasurface with respect to the cardinal plane. Benefiting from its strong chirality and spin-dependent transmission characteristics, the proposed folded metasurface may be applied to a range of novel photon-spin selective devices for optical communication technologies and biophotonics.

9.
Hortic Res ; 5: 23, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29736248

RESUMO

Litchi is one of the most important subtropical evergreen fruit trees in southern Asia. Previous studies indicated that high-temperature conditions encourage growth of rudimentary leaves in panicles and suppress flowering. We have demonstrated that methyl viologen dichloride hydrate (MV) and sodium nitroprusside (SNP) promoted flowering in litchi partially by inhibiting the growth of rudimentary leaves via reactive oxygen species (ROS) and nitric oxide (NO). In the present study, we examined the microstructure and ultrastructure, programmed cell death (PCD) ratio, nuclei morphology of the rudimentary leaves, and the expression of senescence-related genes after the treatment with ROS or NO. The results showed that chromatins of the ROS- or NO-treated cells in the rudimentary leaves were condensed. Fusion of the cytoplasm-digesting vesicles with the vacuole and degradation of cytoplasm forming scattered debris were found in those of the treated cells. Treatment with ROS or NO increased the cell PCD ratio. Morphology of the nuclei stained by propidium iodide (PI) showed that nuclei shape became irregular after the ROS or NO treatment. Further, the expression levels of LcRboh, LcMC-1-like, and LcPirin were higher in the ROS- and NO-treated rudimentary leaves than those in the control ones, suggesting that these genes may be involved in the ROS and NO-induced senescence and abscission of the rudimentary leaves in litchi. Our results suggested that ROS and NO play an important role in inducing the senescence of the rudimentary leaves, and ROS- and NO-induced PCD may be involved in the regulation of the rudimentary leaf growth in litchi.

11.
Sci Rep ; 7(1): 15590, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-29142227

RESUMO

The phylogeographic structure of the land snail Camaena cicatricosa was analyzed in this study based on mitochondrial gene (COI and 16srRNA, mt DNA) and internal transcribed spacer (ITS2) sequences in 347 individuals. This snail is the vector of the zoonotic food-borne parasite Angiostrongylus cantonensis and one of the main harmful snails distributed exclusively in China. The results revealed significant fixation indices of genetic differentiation and high gene flow between most populations except several populations. An isolation-by-distance test showed no significant correlation between genetic distance and geographical distance among C. cicatricosa populations, which suggested that gene flow was not restricted by distance. The levels of haplotype and nucleotide diversity of C. cicatricosa were generally high, except those in some special populations, according to the mt DNA and ITS2 data. Furthermore, the phylogenetic trees and asteroid networks of haplotypes indicated nonobvious genetic structure, the same as results got based on the synonymous and non synonymous sites of 347 sequences of the COI gene. All lines of evidence indicated that climatic changes and geographical and human barriers do not substantially affect the current population structure and distribution of the investigated snails.


Assuntos
DNA Intergênico/genética , DNA Mitocondrial/genética , Genética Populacional , Caramujos/genética , Animais , China , Estruturas Genéticas , Variação Genética/genética , Haplótipos/genética , Humanos , Filogeografia , RNA Ribossômico 16S/genética
12.
Zhongguo Yi Liao Qi Xie Za Zhi ; 41(4): 302-305, 2017 Jul 30.
Artigo em Chinês | MEDLINE | ID: mdl-29862796

RESUMO

The craniospinal radiotherapy method was studied by using the whole body positioning frame and base dose plan compensation (BDPC) technique.11 patients with central nervous system malignancies in our hospital were studied. Use whole body positioning frame with the head-neck shoulder and body membrane to immobilize posture, then use BDPC for the intensity-modulated radiotherapy. Target area conformability index(CI), homogeneity index (HI), dose of endangerment organ (OAR) and beam connecting dose distribution are evaluated. The use of base-dosecompensation intensity-modulated plan combined with whole-body positioning technology improves the target area conformability and target uniformity, simplifies the design of craniospinal radiotherapy, improves the placement accuracy and ensure good placement repeatability. We measure beam connecting dose distribution. Cold and hot spots do not appear, and calculated values are basically identical. The application of whole-body positioning technique combined with BDPC optimization method in the treatment of the craniospinal radiotherapy meets the clinical requirements of dosimetry. Moreover, it is simple and can improve the treatment planning efficiency.


Assuntos
Radiação Cranioespinal , Radioterapia de Intensidade Modulada , Humanos , Radiometria , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
13.
Nano Lett ; 16(11): 6870-6878, 2016 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-27786486

RESUMO

The capabilities to tune the conduction properties of materials by doping or electric fields are essential for the design of electronic devices. However, in two-dimensional materials substitutional doping has been achieved in only a few systems, such as Nb substitutional doping in MoS2. Surface charge transfer is still one of the popular ways to control whether the conduction is dominated by holes or electrons. Here, we demonstrate that a capping layer of cross-linked poly(methyl methacrylate) modifies the potential in a black phosphorus (BP) layer so that conduction in the absence of an external electric field is dominated by electrons, rather than holes. Using this technique to form adjoining regions dominated by hole and electron conduction, a family of novel planar devices, such as BP-gated diodes, BP bidirectional rectifier, and BP logic inverters, can be fabricated. The devices are potentially useful for electronic applications, including rectification and switching.

14.
Sci Rep ; 6: 28764, 2016 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-27357610

RESUMO

One of the key motivations in producing 3D structures has always been the realization of metamaterials with effective constituent properties that can be tuned in all propagation directions at various frequencies. Here, we report the investigation of spatially oriented "Nanograter" structures with orientation-dependent responses over a wide spectrum by focused-ion-beam based patterning and folding of thin film nanostructures. Au nano units of different shapes, standing along specifically designated orientations, were fabricated. Experimental measurements and simulation results show that such structures offer an additional degree of freedom for adjusting optical properties with the angle of inclination, in additional to the size of the structures. The response frequency can be varied in a wide range (8 µm-14 µm) by the spatial orientation (0°-180°) of the structures, transforming the response from magnetic into electric coupling. This may open up prospects for the fabrication of 3D nanostructures as optical interconnects, focusing elements and logic elements, moving toward the realization of 3D optical circuits.

15.
Sci Rep ; 3: 3191, 2013 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-24217130

RESUMO

We demonstrate the optical orbital angular momentum conservation during the transfer process from subwavelength plasmonic vortex lens (PVLs) to light and the generating process of surface plasmon polaritons (SPPs). Illuminating plasmonic vortex lenses with beams carrying optical orbital angular momentum, the SP vortices with orbital angular momentum were generated and inherit the optical angular momentum of light beams and PVLs. The angular momentum of twisting SP electromagnetic field is tunable by the twisted metal/dielectric interfaces of PVLs and angular momentum of illuminating singular light. This work may open the door for several possible applications of SP vortices in subwavelength region.

16.
ACS Appl Mater Interfaces ; 5(13): 6097-107, 2013 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-23749192

RESUMO

An ultrathin layer is investigated for its potential application of replacing conventional diffusion barriers and promoting interface adhesion for nanoelectric circuits with porous ultralow dielectrics. The porous ultralow dielectric (k ≈ 2.5) substrate is silanized by 3-aminopropyltrimethoxysilane (APTMS) to form the nanoadhesive layer by performing oxygen plasma modification and tailoring the silanization conditions appropriately. The high primary amine content is obtained in favor of strong interaction between amino groups and copper. And the results of leakage current measurements of metal-oxide-semiconductor capacitor structure demonstrate that the aminosilanization nanoadhesive layer can block copper diffusion effectively and guarantee the performance of devices. Furthermore, the results of four-point bending tests indicate that the nanoadhesive layer with monolayer structure can provide the satisfactory interface toughness up to 6.7 ± 0.5 J/m(2) for Cu/ultralow-k interface. Additionally, an annealing-enhanced interface toughness effect occurs because of the formation of Cu-N bonding and siloxane bridges below 500 °C. However, the interface is weakened on account of the oxidization of amines and copper as well as the breaking of Cu-N bonding above 500 °C. It is also found that APTMS nanoadhesive layer with multilayer structure provides relatively low interface toughness compared with monolayer structure, which is mainly correlated to the breaking of interlayer hydrogen bonding.

17.
J Nanosci Nanotechnol ; 13(2): 1199-202, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23646602

RESUMO

The movement of the magnetic domain wall could result in the changing of the contact resistance. Such a resistance change is named as the domain wall Magnetoresistance (DWMR), which can be used as a basic signal of nanodevices. For application, a large DWMR is necessary to improve the device performance. An approach to improve the DWMR value is to fabricate magnetic structures with narrow contact width. However, due to the proximity effect during the process of electron beam lithography (EBL), it is not easy to fabricate sub-20 nm width structures by EBL technique directly. In this paper, we investigated the fabrication of sub-20 nm width nanocontact structures by combined techniques of EBL and shadow evaporation. Upon optimizing the resist thickness, opening width, and the evaporation angle, the contact width was tuned and the corresponding variation trends with these parameters were explored. Using the optimized fabrication conditions, 14 nm wide ferromagnetic contact structures were successfully fabricated.

18.
Nanotechnology ; 23(27): 275503, 2012 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-22706679

RESUMO

Metamaterials (MMs) have shown huge potential in sensing applications by detecting their optical properties, which can be designed to operate at frequencies from visible to mid-IR. Here we constructed complementary split ring resonator (CSRR) based metamaterials in nanoscale with unit length of 100 nm and slit width of 30 nm, and observed obvious responses in the visible waveband from 600 to 900 nm. These visible responses show a good tunability with the structure's geometry, and are well suited for dielectric detection. We demonstrated good refractive index sensing of CSRR based metamaterials in the visible region under both 0° and 90° polarized incidence. Our results extend the study of CSRR based metamaterials to the visible region, which is expected to deepen the understanding of the response mechanism of CSRRs and benefit their sensing applications in the visible region.


Assuntos
Nanopartículas/química , Nanopartículas/ultraestrutura , Nanotecnologia/instrumentação , Refratometria/instrumentação , Transdutores , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Espalhamento de Radiação
19.
Biosci Rep ; 32(2): 139-51, 2012 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21679158

RESUMO

RDR6 (RNA-dependent RNA polymerase 6) is not only involved in virus resistance but also plays an important role in natural plant development. In the present study, a novel RDR gene, named GhRDR6 (Gossypium hirsutum RDR6), was isolated from cotton (G. hirsutum L.). Alignment and evolutionary relationship analyses showed that GhRDR6 was more closely related to RDR6 than to other RDRs. Expression analysis indicated that this single-copy gene is constitutively expressed in the roots, stems and leaves. Semi-quantitative RT-PCR (reverse transcription-PCR) showed that GhRDR6 was up-regulated by the application of various phytohormones, including MeJA [methyl JA (jasmonate)], ABA (abscisic acid), JA, α-naphthylacetic acid, gibberellins and ET (ethylene). In addition, GhRDR6 expression increased in response to wounding, cold (4°C) and NaCl treatments, but not by drought. Furthermore, overexpression of GhRDR6 in transgenic Nicotiana benthamiana plants resulted in root lengths longer than the wide-type during the seeding stage. Interestingly, the GhRDR6-overexpressing plants displayed reduced tolerance to oxidative damage, resulting in reduced ABA-sensitivity, but they tolerated freezing. Moreover, resistance to potato virus Y was enhanced in transgenic N. benthamiana plants. These results suggest that GhRDR6 may play an important role in plant defence responses and a pivotal role in plant development.


Assuntos
Regulação da Expressão Gênica de Plantas , Gossypium/enzimologia , Gossypium/genética , RNA Polimerase Dependente de RNA/genética , Sequência de Aminoácidos , Clonagem Molecular , Secas , Congelamento , Genes de Plantas , Gossypium/química , Gossypium/crescimento & desenvolvimento , Dados de Sequência Molecular , Doenças das Plantas/genética , Plantas Geneticamente Modificadas/enzimologia , Plantas Geneticamente Modificadas/genética , RNA Polimerase Dependente de RNA/química , RNA Polimerase Dependente de RNA/metabolismo , Alinhamento de Sequência
20.
Chem Commun (Camb) ; 47(33): 9408-10, 2011 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-21773610

RESUMO

We report thickness-dependent morphologies of a Pd film on n-layer graphenes. Via Raman spectroscopy-based technique, obvious charge transfer has been observed among Pd and graphenes, which is also dependent on the layer number. With the increase of the layer number, the Pd film becomes coarser, and the electron transfer becomes lower.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA