Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 138
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Angew Chem Int Ed Engl ; 63(25): e202406374, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38627207

RESUMO

Zeolitic octahedral metal oxide is a newly synthesized all-inorganic zeolitic material and has been used for adsorption, separation, and catalysis. Herein, a new zeolitic octahedral metal oxide was synthesized and characterized. The porous framework was established through the assembly of [P2Mo13O50] clusters with PO4 linkers. Guest molecules occupied the framework, which could be removed through heat treatment, thereby opening the micropores. The pore characteristics were controlled by the cations within the micropore, enabling the adjustment of the interactions with alkynes and alkenes. This resulted in good separation performance of ethylene/acetylene and propylene/propyne even under high temperature and humidity conditions. The high stability of the material enabled the efficient recovery and reuse without discernible loss in the separation performance. Due to the relatively weak interaction between the adsorbed alkyne and the framework, the adsorbent facilitated the recovery of a highly pure alkyne. This feature enhances the practical applicability of the material in various industrial processes.

2.
Syst Biol ; 71(3): 690-705, 2022 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-34524452

RESUMO

Integrative taxonomy is central to modern taxonomy and systematic biology, including behavior, niche preference, distribution, morphological analysis, and DNA barcoding. However, decades of use demonstrate that these methods can face challenges when used in isolation, for instance, potential misidentifications due to phenotypic plasticity for morphological methods, and incorrect identifications because of introgression, incomplete lineage sorting, and horizontal gene transfer for DNA barcoding. Although researchers have advocated the use of integrative taxonomy, few detailed algorithms have been proposed. Here, we develop a convolutional neural network method (morphology-molecule network [MMNet]) that integrates morphological and molecular data for species identification. The newly proposed method (MMNet) worked better than four currently available alternative methods when tested with 10 independent data sets representing varying genetic diversity from different taxa. High accuracies were achieved for all groups, including beetles (98.1% of 123 species), butterflies (98.8% of 24 species), fishes (96.3% of 214 species), and moths (96.4% of 150 total species). Further, MMNet demonstrated a high degree of accuracy ($>$98%) in four data sets including closely related species from the same genus. The average accuracy of two modest subgenomic (single nucleotide polymorphism) data sets, comprising eight putative subspecies respectively, is 90%. Additional tests show that the success rate of species identification under this method most strongly depends on the amount of training data, and is robust to sequence length and image size. Analyses on the contribution of different data types (image vs. gene) indicate that both morphological and genetic data are important to the model, and that genetic data contribute slightly more. The approaches developed here serve as a foundation for the future integration of multimodal information for integrative taxonomy, such as image, audio, video, 3D scanning, and biosensor data, to characterize organisms more comprehensively as a basis for improved investigation, monitoring, and conservation of biodiversity. [Convolutional neural network; deep learning; integrative taxonomy; single nucleotide polymorphism; species identification.].


Assuntos
Borboletas , Animais , Biodiversidade , Borboletas/genética , DNA/genética , Código de Barras de DNA Taxonômico/métodos , Redes Neurais de Computação , Filogenia
3.
Langmuir ; 39(29): 10163-10177, 2023 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-37436774

RESUMO

Au nanoparticles are efficient catalysts for selective oxidations. The interaction between Au nanoparticles and supports is critical for achieving high catalytic activity. Herein, Au nanoparticles are supported on a zeolitic octahedral metal oxide based on Mo and V. The charge of Au is controlled by the surface oxygen vacancies of the supports, and the redox property of the zeolitic vanadomolybdate is highly dependent on Au loading. The Au-supported zeolitic vanadomolybdate is used as a heterogeneous catalyst for alcohol oxidation under mild conditions with molecular oxygen as an oxidant. The supported Au catalyst can be recovered and reused without the loss of activity.

4.
Chemistry ; 28(41): e202200618, 2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-35581526

RESUMO

Zeolitic octahedral metal oxides are inorganic crystalline microporous materials with adsorption and redox properties. New ϵ-Keggin nickel molybdate-based zeolitic octahedral metal oxides have been synthesized. 31 P NMR spectroscopy shows that reduction of MoVI -based molybdates forms an ϵ-Keggin polyoxometalate that immediately transfers to the solid phase. Investigation of the formation process indicates that a low Ni concentration, insoluble reducing agent, and long synthesis time are the critical factors for obtaining the zeolite octahedral metal oxides rather than the ϵ-Keggin polyoxometalate molecule. The synthesized zeolitic nickel molybdate with Na+ is used as the adsorbent, which effectively separates C2 hydrocarbon mixtures.

5.
Inorg Chem ; 61(26): 10133-10143, 2022 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-35737438

RESUMO

Synthetic conditions for the zeolitic octahedral metal oxide based on vanadotungstate are studied. The temperature, time, acidity, W/V ratio, cation species, and concentration affect the resulting materials. The study shows that mixing tungstate and VO2+ in an aqueous solution generates cubane units ([W4O16]8-) at room temperature. The cubane units assemble with VO2+ immediately to form a solid with an amorphous phase and nonporosity, which further crystallizes under a hydrothermal condition to form the crystalline microporous vanadotungstate. The zeolitic vanadotungstates act as effective adsorbents for the separation of propylene/propane. The active materials effectively separate propylene/propane even at high temperatures and high humidities.

6.
Angew Chem Int Ed Engl ; 61(37): e202209121, 2022 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-35852031

RESUMO

Separation of CO2 /C2 H2 to obtain pure C2 H2 presents a challenge for the chemical industry. CO2 -selective adsorbents are favored because of the convenient separation process. However, there are only a few CO2 -selective adsorbents that can effectively isolate CO2 from CO2 /C2 H2 , and there is almost no research on CO2 /C2 H2 separation under harsh conditions, such as with high temperatures and humidities. Herein, a zeolitic octahedral metal oxide based on ϵ-Keggin polyoxometalates is utilized for separations of CO2 /C2 H2 at high temperatures and humidities. Single gas adsorption measurements show that the material only adsorbs CO2 with almost no C2 H2 taken up. Dynamic competitive adsorption experiments show that the material efficiently separates CO2 /C2 H2 , and highly pure C2 H2 is obtained directly. The robust material maintains a high separation performance at 333 K with 18.12 % water. The high stability of the material enables reuse without loss of separation performance.

7.
Cancer Cell Int ; 21(1): 584, 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-34717645

RESUMO

BACKGROUND: Hypopharyngeal cancer (HPC) is associated with a poor prognosis and a high recurrence rate. Immune escape is one of the reasons for the poor prognosis of malignant tumors. Programmed cell death ligand 1 (PD-L1) and programmed cell death-1 (PD-1) have been shown to play important roles in immune escape. However, the role of PD-1/PD-L1 in HPC remains unclear. In this experiment, we investigated the effect of exosomes from HPC patient serum on CD8+ T cell function and PD-1/PD-L1 expression and, thus, on prognosis. We hope to provide guidance for the identification of new targets for HPC immunotherapy. METHODS: PD-1 and CD8 expression in 71 HPC tissues and 16 paracarcinoma tissues was detected by immunohistochemistry. Concurrently, the clinicopathological data of the patients were obtained to conduct correlation analysis. Exosomes were isolated from serum and then identified by Western blotting (WB), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). Flow cytometry was used to assess the activity of CD8+ T cells after exosome stimulation. The effects of exosomes on the ability of CD8+ T cells to kill FaDu cells were assessed by CCK-8 assay. The expression of IL-10 and TGF-ß1 was measured by enzyme-linked immunosorbent assay (ELISA). PD-L1 expression in HPC tissue samples was evaluated by immunohistochemistry, and the relationship between PD-1/PD-L1 expression and prognosis was investigated with patient specimens. RESULTS: PD-1 expression was significantly upregulated on CD8+ T cells in tumor tissues compared with those in normal tissues. The overall survival (OS) and disease-free survival (DFS) of PD-1-overexpressing patients were decreased. Serum exosomes from patients can elevate PD-1 expression on CD8+ T cells and suppress their killing capacity and secretory function. The rate of positive PD-L1 expression was increased in HPC tissues compared with paracancerous tissues. The DFS and OS of the PD-1(+)-PD-L1(+) group were significantly lower than those of the PD-1(-)-PD-L1(-) group. CONCLUSION: Our findings indicate that serum exosomes from HPC patients can inhibit CD8+ T cell function and that the PD-1-PD-L1 pathway plays an important role in the immune escape of HPC. Exosomes combined with immunotherapy may guide the treatment of patients with advanced disease in the future.

8.
Chemistry ; 27(51): 13067-13071, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34216062

RESUMO

Zeolitic vanadotungstates with tunable microporosity have potential interests in gas separation. The pore openings of the materials are in between the diameters of normal butane and isobutane, which causes the materials only adsorb normal butane. The breakthrough experiments show that the materials effectively separate normal butane from the normal butane and isobutane mixture even at high temperatures. The robust materials can be reused without loss of the separation performance.

9.
Artigo em Inglês | MEDLINE | ID: mdl-34431438

RESUMO

Metal tetrakis(1-methylpyridinium-4-yl)porphyrins were immobilized on sulfonated SBA-15 (MTMPyP-SO3-pr-SBA-15, M = Fe, Mn, Zn) for oxidative degradation of 2,4,6-tribromophenol in the presence of humic substances. The influence of the central metal of metalloporphyrins, pH, and catalyst dosage on the 2,4,6-tribromophenol degradation was investigated. FeTMPyP-SO3-pr-SBA-15 and MnTMPyP-SO3-pr-SBA-15 showed the catalytic activities. The activity of MnTMPyP-SO3-pr-SBA-15 was more strongly inhibited by humic substances than that of FeTMPyP-SO3-pr-SBA-15. Kinetic study indicated that humic substances suppressed the generation of high valent metal-oxo species in MnTMPyP-SO3-pr-SBA-15 at slightly acid condition. There was a clear linear relationship between the content of phenolic-OH and aromatic-C in humic substances and the corresponding inhibition ability. The inhibition by humic substances is probably ascribed to the coordination of humic substances with the monopersulfate species of MnTMPyP-SO3-pr-SBA-15, which prevented the formation of the reactive Mn-oxo species.


Assuntos
Substâncias Húmicas , Porfirinas , Estresse Oxidativo , Fenóis , Compostos de Piridínio , Dióxido de Silício
10.
Angew Chem Int Ed Engl ; 60(33): 18328-18334, 2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34056813

RESUMO

Separation of C2 hydrocarbons, C2 H6 , C2 H4 , and C2 H2 , remains significant challenges in chemical industry. However, there are only few adsorbents that can effectively isolate C2 hydrocarbons from their mixtures particularly at a high temperature. Herein, we design a zeolitic octahedral metal oxide based on ϵ-Keggin polyoxometalates with metal ion linkers. Single gas adsorption of the material shows the different adsorption performances for the C2 hydrocarbons and the strong interaction of the material with the C2 hydrocarbons. Dynamic competitive adsorption experiments show that the material efficiently separates each of the binary C2 hydrocarbon mixtures and even the ternary C2 hydrocarbon mixtures with high selectivity. The material keeps high separation performance even the temperature was increased to 85 °C. The material is stable and is able to be reused without loss of the separation performance.

11.
Inorg Chem ; 59(22): 16557-16566, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33100003

RESUMO

Transition-metal oxide molecular wires are inorganic 1D polymers with elemental diversity. The properties of the materials are tuned by tuning the chemical compositions. The phosphovanadomolybdate molecular wire is synthesized, which is an isostructural material of the phosphomolybdate molecular wire. V is randomly located in the crystal to form {[(HPIIIO3)(MoVI5O15)(VVO3)]3-}n, which is incorporated into the material after the formation of the phosphomolybdate molecular wire. The heat-triggered redox reaction via the intramolecular electron-transfer and oxygen-transfer procedure is promoted after V substitution. Oxygen transfers from {VVO6} to {HPIIIO3}, and an electron transfers from {HPIIIO3} to {VVO6} with oxidation of the triangle {HPIIIO3} to the corner-sharing tetrahedral {PV2O7} and reduction of the octahedral {VVO6} to the pyramidal {VIVO5}. The material shows catalytic activity for the aerobic oxidation of alcohol to aldehyde, and good activity with high selectivity is obtained.

12.
Sensors (Basel) ; 20(17)2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32872218

RESUMO

Due to the limitation of less information in a single image, it is very difficult to generate a high-precision 3D model based on the image. There are some problems in the generation of 3D voxel models, e.g., the information loss at the upper level of a network. To solve these problems, we design a 3D model generation network based on multi-modal data constraints and multi-level feature fusion, named as 3DMGNet. Moreover, 3DMGNet is trained by self-supervised method to achieve 3D voxel model generation from an image. The image feature extraction network (2DNet) and 3D feature extraction network (3D auxiliary network) are used to extract the features of the image and 3D voxel model. Then, feature fusion is used to integrate the low-level features into the high-level features in the 3D auxiliary network. To extract more effective features, each layer of the feature map in feature extraction network is processed by an attention network. Finally, the extracted features generate 3D models by a 3D deconvolution network. The feature extraction of 3D model and the generation of voxelization play an auxiliary role in the training of the whole network for the 3D model generation based on an image. Additionally, a multi-view contour constraint method is proposed, to enhance the effect of the 3D model generation. In the experiment, the ShapeNet dataset is adapted to prove the effect of the 3DMGNet, which verifies the robust performance of the proposed method.

13.
BMC Genet ; 20(1): 91, 2019 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-31801457

RESUMO

BACKGROUND: The plant-specific Teosinte branched1/Cycloidea/Proliferating cell factor (TCP) family of transcription factors is involved in the regulation of cell growth and proliferation, performing diverse functions in plant growth and development. In addition, TCP transcription factors have recently been shown to be targets of pathogenic effectors and are likely to play a vital role in plant immunity. No comprehensive analysis of the TCP family members in potato (Solanum tuberosum L.) has been undertaken, however, and whether their functions are conserved in potato remains unknown. RESULTS: To assess TCP gene evolution in potato, we identified TCP-like genes in several publicly available databases. A total of 23 non-redundant TCP transcription factor-encoding genes were identified in the potato genome and subsequently subjected to a systematic analysis that included determination of their phylogenetic relationships, gene structures and expression profiles in different potato tissues under basal conditions and after hormone treatments. These assays also confirmed the function of the class I TCP StTCP23 in the regulation of plant growth and defence. CONCLUSIONS: This is the first genome-wide study including a systematic analysis of the StTCP gene family in potato. Identification of the possible functions of StTCPs in potato growth and defence provides valuable information for our understanding of the classification and functions of the TCP genes in potato.


Assuntos
Resistência à Doença/genética , Perfilação da Expressão Gênica/métodos , Solanum tuberosum/crescimento & desenvolvimento , Fatores de Transcrição/genética , Sequenciamento Completo do Genoma/métodos , Evolução Molecular , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla , Família Multigênica , Imunidade Vegetal , Proteínas de Plantas/genética , Solanum tuberosum/genética , Estresse Fisiológico
14.
Inorg Chem ; 58(18): 12272-12279, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31465205

RESUMO

Phosphomolybdates with different P species exhibiting a 1D molecular structure are synthesized. The materials are constructed by a {[MoVI6O21]6-}n molecular tube as a shell with trapping a redox-active species P in the center. The building units ([(HPIIIO3)MoVI6O18]2- or [(PV2O7)MoVI12O36]4-) form at room temperature, which further polymerize linearly along the c-axis. Interestingly, the material shows an unusual heat-triggered intramolecular redox property, which undergoes an electron-transfer-oxygen-transfer procedure from [{(HPIIIO3)MoVI6O18]2-}n to {[(PV2O7)MoVI12O36]4-}n/2. The crystal structure of the material is stable during the oxidation reaction, while the central P is oxidized and the local structure changes.

15.
Inorg Chem ; 58(9): 6283-6293, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31013070

RESUMO

The design and development of zeolitic transition metal oxides for selective oxidation are interesting due to the combination of the redox properties and microporosities. Redox-active zeolitic transition metal oxides based on ε-Keggin iron molybdates were synthesized. O2 can be activated by the materials via an electron-transfer-based process, and the materials can be oxidized even at room temperature. The materials are oxidized and reduced reversibly while the crystal structures are maintained. V is uniformly incorporated in the materials without changing the basic structures, and the redox properties of the materials are tuned by V. The materials are used as robust catalysts for ethyl lactate oxidation to form ethyl pyruvate using O2 as an oxidant.

16.
Sensors (Basel) ; 18(11)2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30388781

RESUMO

Urban land cover and land use mapping plays an important role in urban planning and management. In this paper, novel multi-scale deep learning models, namely ASPP-Unet and ResASPP-Unet are proposed for urban land cover classification based on very high resolution (VHR) satellite imagery. The proposed ASPP-Unet model consists of a contracting path which extracts the high-level features, and an expansive path, which up-samples the features to create a high-resolution output. The atrous spatial pyramid pooling (ASPP) technique is utilized in the bottom layer in order to incorporate multi-scale deep features into a discriminative feature. The ResASPP-Unet model further improves the architecture by replacing each layer with residual unit. The models were trained and tested based on WorldView-2 (WV2) and WorldView-3 (WV3) imageries over the city of Beijing. Model parameters including layer depth and the number of initial feature maps (IFMs) as well as the input image bands were evaluated in terms of their impact on the model performances. It is shown that the ResASPP-Unet model with 11 layers and 64 IFMs based on 8-band WV2 imagery produced the highest classification accuracy (87.1% for WV2 imagery and 84.0% for WV3 imagery). The ASPP-Unet model with the same parameter setting produced slightly lower accuracy, with overall accuracy of 85.2% for WV2 imagery and 83.2% for WV3 imagery. Overall, the proposed models outperformed the state-of-the-art models, e.g., U-Net, convolutional neural network (CNN) and Support Vector Machine (SVM) model over both WV2 and WV3 images, and yielded robust and efficient urban land cover classification results.

17.
Hum Brain Mapp ; 38(2): 831-841, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27699945

RESUMO

This study investigated interactive exchange in lovers and the associated interpersonal brain synchronization (IBS) using functional near-infrared spectroscopy (fNIRS)-based hyperscanning. Three types of female-male dyads, lovers, friends, and strangers, performed a cooperation task during which brain activity was recorded in right frontoparietal regions. We measured better cooperative behavior in lover dyads compared with friend and stranger dyads. Lover dyads demonstrated increased IBS in right superior frontal cortex, which also covaried with their task performance. Granger causality analyses in lover dyads revealed stronger directional synchronization from females to males than from males to females, suggesting different roles for females and males during cooperation. Our study refines the theoretical explanation of romantic interaction between lovers. Hum Brain Mapp 38:831-841, 2017. © 2016 Wiley Periodicals, Inc.


Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Comportamento Cooperativo , Amor , Espectroscopia de Luz Próxima ao Infravermelho , Análise de Variância , Feminino , Humanos , Relações Interpessoais , Masculino , Tempo de Reação/fisiologia , Caracteres Sexuais , Estatísticas não Paramétricas , Adulto Jovem
18.
Chemistry ; 23(69): 17497-17503, 2017 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-28885750

RESUMO

The extended 1D tungstophosphite molecular wire is obtained by connection of polyoxometalates. Self-assembly of a triangular PIII O3 unit with tungstate produces a hexagonal [HPIII W6 O21 ]2- building block, which then connects linearly to form the molecular wire. The surface property of the molecular wire is tuned to hydrophobic using organoammonium cations, and the surface-modified material disperses easily in organic media. The multifunctional material, which possesses nanostructure, hydrophobicity, and redox properties simultaneously, is suitable for olefin epoxidation in organic solvent.

19.
Chemistry ; 23(8): 1972-1980, 2017 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-27935181

RESUMO

An all-inorganic soft framework is rare but interesting for both fundamental research and practical applications. Here, an all-inorganic soft framework based on a transition metal oxide is reported. The periodic connection of a one-dimensional anionic tungstoselenate molecular wire building block with a CoII ion is used to construct the crystalline material. The crystal structure of the material was determined by high-angle annular dark-field scanning transmission electron microscopy combined with several characterization techniques. The soft framework of the material enables water adsorption/desorption with a change in its structure, leading to a high level of water adsorption. The framework of the material is flexible, and the structure of the molecular wire building block is stable during the water adsorption/desorption process.

20.
Inorg Chem ; 56(22): 14306-14314, 2017 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-29099177

RESUMO

The structural determination of nanomaterials and their application in energy storage and transfer are of great importance. Herein, a layered zirconomolybdate with a two-dimensional structure was synthesized. Atomic resolution electron microscopy was utilized for direct visualization of the structure that was further confirmed by powder X-ray diffraction and X-ray absorption near-edge structure analyses. The structure of the molecular sheet was stable at a high temperature in an oxidative atmosphere. The electrochemical performance of the material was evaluated with a Li battery composed of the calcined material as a cathode. Li ions were reversibly inserted and extracted between the layers without collapse of the structure of the material. The electrochemical properties of the material were derived from the reversible redox activity of the Mo ions and Zr ions in the material as well as the flexibility of the molecular layer of the material.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA