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1.
FASEB J ; 37(9): e23111, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37531300

RESUMO

The post-transfer developmental capacity of bovine somatic cell nuclear transfer (SCNT) blastocysts is reduced, implying that abnormalities in gene expression regulation are present at blastocyst stage. Chromatin accessibility, as an indicator for transcriptional regulatory elements mediating gene transcription activity, has heretofore been largely unexplored in SCNT embryos, especially at blastocyst stage. In the present study, single-cell sequencing assay for transposase-accessible chromatin (scATAC-seq) of in vivo and SCNT blastocysts were conducted to segregate lineages and demonstrate the aberrant chromatin accessibility of transcription factors (TFs) related to inner cell mass (ICM) development in SCNT blastocysts. Pseudotime analysis of lineage segregation further reflected dysregulated chromatin accessibility dynamics of TFs in the ICM of SCNT blastocysts compared to their in vivo counterparts. ATAC- and ChIP-seq results of SCNT donor cells revealed that the aberrant chromatin accessibility in the ICM of SCNT blastocysts was due to the persistence of chromatin accessibility memory at corresponding loci in the donor cells, with strong enrichment of trimethylation of histone H3 at lysine 4 (H3K4me3) at these loci. Correction of the aberrant chromatin accessibility through demethylation of H3K4me3 by KDM5B diminished the expression of related genes (e.g., BCL11B) and significantly improved the ICM proliferation in SCNT blastocysts. This effect was confirmed by knocking down BCL11B in SCNT embryos to down-regulate p21 and alleviate the inhibition of ICM proliferation. These findings expand our understanding of the chromatin accessibility abnormalities in SCNT blastocysts and BCL11B may be a potential target to improve SCNT efficiency.


Assuntos
Cromatina , Técnicas de Transferência Nuclear , Animais , Bovinos , Cromatina/genética , Cromatina/metabolismo , Blastocisto/metabolismo , Desenvolvimento Embrionário/genética , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo
2.
Small ; 19(46): e2303985, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37442792

RESUMO

Potassium-ion batteries (PIBs) have broad application prospects in the field of electric energy storage systems because of its abundant K reserves, and similar "rocking chair" operating principle as lithium-ion batteries (LIBs). Aiming to the large volume expansion and sluggish dynamic behavior of anode materials for storing large sized K-ion, bismuth telluride (Bi2 Te3 ) nanoplates hierarchically encapsulated by reduced graphene oxide (rGO), and nitrogen-doped carbon (NC) are constructed as anodes for PIBs. The resultant Bi2 Te3 @rGO@NC architecture features robust chemical bond of Bi─O─C, tightly physicochemical confinement effect, typical conductor property, and enhanced K-ion adsorption ability, thereby producing superior electrochemical kinetics and outstanding morphological and structural stability. It is visually elucidated via high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) that conversion-alloying dual-mechanism plays a significant role in K-ion storage, allowing 12 K-ion transport per formular unit employing Bi as redox site. Thus, the high first reversible specific capacity of 322.70 mAh g-1 at 50 mA g-1 , great rate capability and cyclic stability can be achieved for Bi2 Te3 @rGO@NC. This work lays the foundation for an in-depth understanding of conversion-alloying mechanism in potassium-ion storage.

3.
Biol Reprod ; 109(3): 282-298, 2023 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-37498179

RESUMO

In vitro maturation of mammalian oocytes is an important means in assisted reproductive technology. Most bovine immature oocytes complete nuclear maturation, but less than half develop to the blastocyst stage after fertilization. Thus, inefficient in vitro production is mainly caused by a suboptimal in vitro culture process, in which oocyte quality appears to be the limiting factor. In our study, a potential maternal regulator, C-X-C motif chemokine ligand 12, was identified by analyzing transcriptome data. C-X-C motif chemokine ligand 12 supplementation promoted the developmental potential of oocytes by improving protein synthesis and reorganizing cortical granules and mitochondria during in vitro maturation, which eventually increased blastocyst formation efficiency and cell number after parthenogenesis, fertilization, and cloning. All these promoting effects by C-X-C motif chemokine ligand 12 were achieved by activating SH2 domain-containing tyrosine phosphatase 2, thereby promoting the mitogen-activated protein kinase signaling pathway. These findings provide an in vitro maturation system that closely resembles the maternal environment to provide high-quality oocytes for in vitro production.


Assuntos
Oócitos , Domínios de Homologia de src , Bovinos , Animais , Ligantes , Oócitos/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Quimiocinas/metabolismo , Tirosina/metabolismo , Técnicas de Maturação in Vitro de Oócitos/veterinária , Blastocisto/metabolismo , Fertilização in vitro , Mamíferos/metabolismo
4.
Analyst ; 148(14): 3295-3305, 2023 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-37318011

RESUMO

Highly sensitive protein biomarker detection is critical for the diagnosis of gastric cancer (GC), however the accurate and sensitive detection of low-abundance proteins in early-stage GC is still a challenge. Herein, a surface-enhanced Raman scattering frequency shift assay was performed on a developed microfluidic chip for the detection of GC protein biomarkers carcinoembryonic antigen (CEA) and vascular endothelial growth factor (VEGF). The chip is made up of three groups of parallel channels and each parallel channel consists of two reaction regions, enabling the simultaneous analysis of multiple biomarkers in multiple samples. The presence of CEA and VEGF in the sample can be captured by the 4-mercaptobenzoic acid (4-MBA)-conjugated antibody functionalized gold nano-sheet (GNS-) substrate, resulting in the Raman frequency shift. As a result, a typical Raman frequency shift of 4-MBA presented a linear relationship with the concentration of CEA and VEGF. The limit of detection (LOD) of the proposed SERS microfluidic chip reaches as low as 0.38 pg mL-1 for CEA and 0.82 pg mL-1 for VEGF. During the detection process, only one step of sample addition is involved, which eliminates the multiple reaction step-induced nonspecific adsorption and significantly increases the convenience and specificity. In addition, serum samples from GC patients and healthy subjects were tested and the results were in good agreement with the current gold-standard method ELISA, suggesting the potential application of the SERS microfluidic chip in clinical settings for early diagnosis and prognosis of GC.


Assuntos
Nanopartículas Metálicas , Neoplasias Gástricas , Humanos , Biomarcadores Tumorais , Antígeno Carcinoembrionário , Fator A de Crescimento do Endotélio Vascular , Microfluídica , Neoplasias Gástricas/diagnóstico , Limite de Detecção , Análise Espectral Raman/métodos
5.
J Am Chem Soc ; 144(11): 4863-4873, 2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35258958

RESUMO

Phase engineering of nanomaterials provides a promising way to explore the phase-dependent physicochemical properties and various applications of nanomaterials. A general bottom-up synthesis method under mild conditions has always been challenging globally for the preparation of the semimetallic phase-transition-metal dichalcogenide (1T'-TMD) monolayers, which are pursued owing to their unique electrochemical property, unavailable in their semiconducting 2H phases. Here, we report the general scalable colloidal synthesis of nanosized 1T'-TMD monolayers, including 1T'-MoS2, 1T'-MoSe2, 1T'-WS2, and 1T'-WSe2, which are revealed to be of high phase purity. Moreover, the surfactant-reliant stacking-hinderable growth mechanism of 1T'-TMD nano-monolayers was unveiled through systematic experiments and theoretical calculations. As a proof-of-concept application, the 1T'-TMD nano-monolayers are used for electrocatalytic hydrogen production in an acidic medium. The 1T'-MoS2 nano-monolayers possess abundant in-plane electrocatalytic active sites and high conductivity, coupled with the contribution of the lattice strain, thus exhibiting excellent performance. Importantly, the catalyst shows impressive endurability in electroactivity. Our developed general scalable strategy could pave the way to extend the synthesis of other broad metastable semimetallic-phase TMDs, which offer great potential to explore novel crystal phase-dependent properties with wide application development for catalysis and beyond.

6.
Small ; 18(8): e2104296, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34873861

RESUMO

The investigation of carbonaceous-based anode materials will promote the fast application of low-cost potassium-ion batteries (PIBs). Here a nitrogen and oxygen co-doped yolk-shell carbon sphere (NO-YS-CS) is constructed as anode material for K-ion storage. The novel architecture, featuring with developed porous structure and high surface specific area, is beneficial to achieving excellent electrochemical kinetics behavior and great electrode stability from buffering the large volume expansion. Furthermore, the N/O heteroatoms co-doping can not only boost the adsorption and intercalation ability of K-ion but also increase the electron transfer capability. It is also demonstrated by experimental results and DFT calculations that K-ion insertion/extraction proceeds through both intercalation and surface capacitive adsorption mechanisms. As expected, the NO-YS-CS electrodes show high initial charge capacity of 473.7 mAh g-1 at 20 mA g-1 , ultralong cycling life over 2500 cycles with the retention of 85.8% at 500 mA g-1 , and superior rate performance (183.3 mAh g-1 at 1.0 A g-1 ). The K-ion full cell, with a high energy density of 271.4 Wh kg-1 and an excellent cyclic stability over 500 cycles, is successfully fabricated with K2 Fe[Fe(CN)6 ] cathode. This work will provide new insight on the synthesis and mechanism understanding of high-performance hard carbon anode for PIBs.

7.
Neuropediatrics ; 53(6): 436-439, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35777662

RESUMO

INTRODUCTION: Focal cortical dysplasia (FCD) is a most common cause of intractable focal epilepsy in children. Surgery is considered as a radical option for such patients with the prerequisite of lesion detection. Magnetic resonance imaging (MRI) plays a significant role in detection of FCDs in epilepsy patients; however, the detection of FCDs even in epilepsy dedicated MRI sequence shows relatively low positive rate. Last year, Middlebrooks et al introduced the novel three-dimensional Edge-Enhancing Gradient Echo (3D-EDGE) MRI sequence and using this sequence successfully identified five cases of FCDs which indicates its potential role in those epilepsy patients who may have FCDs. CASE PRESENTATION: We present a 14-year-old, right-handed, male patient who has suffered from drug-resistant epilepsy over the past 3 years. It was unable to localize the lesion of the seizure, even using the series of epilepsy dedicated MRI sequences. Inspired by the previous report, the lesion of the seizure was successfully targeted by 3D-EDGE sequence. Combined with intraoperative navigation and precisely removed the lesion. He was uneventfully recovered with no signs of cerebral dysfunction and no seizure recurrence 8 months after surgery. CONCLUSION: The 3D-EDGE sequences show a higher sensitivity for FCD detection in epilepsy patients compared with a series of epilepsy-dedicated MRI protocols. We confirmed that the study by Middlebrooks et al is of great clinical value. If the findings on routine MRI sequences or even epilepsy-dedicated MRI sequences were reported as negative, however, the semiology, video-electroencephalography, and fluorodeoxyglucose-positron emission tomography results suggest a local abnormality, and the results are concordant with each other, a 3D-EDGE sequence may be a good option.


Assuntos
Epilepsia Resistente a Medicamentos , Epilepsias Parciais , Epilepsia , Malformações do Desenvolvimento Cortical , Criança , Humanos , Masculino , Adolescente , Malformações do Desenvolvimento Cortical/diagnóstico por imagem , Malformações do Desenvolvimento Cortical/cirurgia , Malformações do Desenvolvimento Cortical/patologia , Imageamento por Ressonância Magnética/métodos , Eletroencefalografia , Epilepsia/diagnóstico por imagem , Epilepsia/etiologia , Convulsões , Epilepsia Resistente a Medicamentos/diagnóstico por imagem , Epilepsia Resistente a Medicamentos/etiologia , Epilepsia Resistente a Medicamentos/cirurgia , Estudos Retrospectivos
8.
J Vasc Res ; 58(3): 180-190, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33794525

RESUMO

Hypertension is considered a risk factor for a series of systematic diseases. Known factors including genetic predisposition, age, and diet habits are strongly associated with the initiation of hypertension. The current study aimed to investigate the role of miR-22-3p in hypertension. In this study, we discovered that the miR-22-3p level was significantly decreased in the thoracic aortic vascular tissues and aortic smooth muscle cells (ASMCs) of spontaneously hypertensive rats. Functionally, the overexpression of miR-22-3p facilitated the switch of ASMCs from the synthetic to contractile phenotype. To investigate the underlying mechanism, we predicted 11 potential target mRNAs for miR-22-3p. After screening, chromodomain helicase DNA-binding 9 (CHD9) was validated to bind with miR-22-3p. Rescue assays showed that the co-overexpression of miR-22-3p and CHD9 reversed the inhibitory effect of miR-22-3p mimics on cell proliferation, migration, and oxidative stress in ASMCs. Finally, miR-22-3p suppressed vascular remodeling and oxidative stress in vivo. Overall, miR-22-3p regulated ASMC phenotype switch by targeting CHD9. This new discovery provides a potential insight into hypertension treatment.


Assuntos
Caderinas/metabolismo , Hipertensão/metabolismo , MicroRNAs/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Estresse Oxidativo , Remodelação Vascular , Animais , Aorta Torácica/metabolismo , Aorta Torácica/patologia , Aorta Torácica/fisiopatologia , Caderinas/genética , Movimento Celular , Proliferação de Células , Modelos Animais de Doenças , Regulação da Expressão Gênica , Hipertensão/genética , Hipertensão/patologia , Hipertensão/fisiopatologia , MicroRNAs/genética , Músculo Liso Vascular/fisiopatologia , Miócitos de Músculo Liso/patologia , Ratos Endogâmicos SHR , Ratos Sprague-Dawley , Transdução de Sinais
9.
J Am Chem Soc ; 142(19): 8953-8961, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32307986

RESUMO

Metal-organic framework (MOF) heterostructures have shown promising applications in gas adsorption, gas separation, catalysis, and energy, arising from the synergistic effect of each component. However, owing to the difficulty in controlling the size, shape, nucleation, and growth of MOFs, it remains a great challenge to construct MOF heterostructures with precisely controlled orientation, morphology, dimensionality, and spatial distribution of each component. Here, we report a seeded epitaxial growth method to prepare a series of hierarchical MOF heterostructures by engineering the structures, sizes, dimensionalities, morphologies, and lattice parameters of both MOF seeds and the secondary MOFs. In these heterostructures, PCN-222 (also known as MOF-545) nanorods selectively grow along the major axis of the ellipsoid-like PCN-608 nanoparticles, on the two end facets of the hexagonal prism-like NU-1000 nanorods, and on the two basal planes of the hexagonal PCN-134 nanoplates, while Zr-BTB nanosheets selectively grow on the six edge facets of PCN-134 nanoplates. The selective epitaxial growth of MOFs opens the way to synthesize different hierarchical heterostructures with tunable architectures and dimensionalities, which could process various promising applications.

10.
J Am Chem Soc ; 142(15): 7161-7167, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32207969

RESUMO

Understanding the reaction mechanism for the catalytic process is essential to the rational design and synthesis of highly efficient catalysts. MoS2 has been reported to be an efficient catalyst toward the electrochemical hydrogen evolution reaction (HER), but it still lacks direct experimental evidence to reveal the mechanism for MoS2-catalyzed electrochemical HER process at the atomic level. In this work, we develop a wet-chemical synthetic method to prepare the single-layer MoS2-coated polyhedral Ag core-shell heterostructure (Ag@MoS2) with tunable sizes as efficient catalysts for the electrochemical HER. The Ag@MoS2 core-shell heterostructures are used as ideal platforms for the real-time surface-enhanced Raman spectroscopy (SERS) study owing to the strong electromagnetic field generated in the plasmonic Ag core. The in situ SERS results provide solid Raman spectroscopic evidence proving the S-H bonding formation on the MoS2 surface during the HER process, suggesting that the S atom of MoS2 is the catalytic active site for the electrochemical HER. It paves the way on the design and synthesis of heterostructures for exploring their catalytic mechanism at atomic level based on the in situ SERS measurement.

11.
Mol Hum Reprod ; 25(8): 471-482, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31041452

RESUMO

Accumulated evidence indicates that sperm-borne small RNA plays a crucial role in embryonic development, especially the absence of the sperm-borne small RNA might be a major cause of the abnormal development of cloned embryos. In this study, we found that sperm-borne small RNA can affect abnormal pronuclear-like structures, postpone the timing of first embryo cleavage and enhance developmental competence of bovine somatic cell nuclear transfer (SCNT) embryos. In addition, the supplementation of sperm-borne small RNA can significantly increase live birth rates and decrease the birth weights of cloned offspring. To investigate the underlying mechanisms, the levels of α-tubulin K40 acetylation (Ac α-tubulin K40) and histone H3 lysine 9 trimethylation (H3K9me3) during early embryo development were investigated in SCNT embryos with sperm-borne small RNA supplementation (termed as T-NT), compared to those normal SCNT embryos and embryos obtained from standard IVF. The results showed that sperm-borne small RNA can significantly decrease the H3K9me3 levels at the pronuclear and two-cell stages, while significantly increase Ac α-tubulin K40 levels at anaphase and telophase of bovine SCNT embryos during the first cleavage. Collectively, our study for the first time demonstrates that sperm-borne small RNA plays a crucial role in the developmental competence of SCNT embryos by regulating H3K9me3 and Ac α-tubulin K40. Further studies will be required to determine how sperm small RNA regulate the H3K9me3 and Acα-tubulin K40. Our study suggests that the supplementation of sperm-borne small RNA is a potential application to improve the cloning efficiency.


Assuntos
Técnicas de Transferência Nuclear , Espermatozoides/metabolismo , Tubulina (Proteína)/metabolismo , Acetilação , Animais , Apoptose/fisiologia , Blastocisto/citologia , Blastocisto/metabolismo , Bovinos , Epigênese Genética/genética , Imunofluorescência , Histonas/metabolismo , Masculino , Microscopia Confocal , Reação em Cadeia da Polimerase , Processamento de Proteína Pós-Traducional , Tubulina (Proteína)/genética
12.
Small ; 14(48): e1803233, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30334350

RESUMO

Durability is still one of the key obstacles for the further development of photocatalytic energy-conversion systems, especially low-dimensional ones. Encouragingly, recent studies show that nanoinsulators such as SiO2 and MgO exhibit substantially enhanced photocatalytic durability than the typical semiconductor p25 TiO2 . Extending this knowledge, MgO-Au plasmonic defect nanosystems are developed that combine the stable photoactivity from MgO surface defects with energy-focusing plasmonics from Au nanoparticles (NPs), where Au NPs are anchored onto monodispersed MgO nanotemplates. Theoretical calculations reveal that the midgap defect (MGD) states in MgO are generated by oxygen vacancies, which provide the main avenues for upward electron transitions under photoexcitation. These electrons drive stable proton photoreduction to H2 gas via water splitting. A synergistic interaction between Au's localized plasmons and MgO's oxygen vacancies is observed here, which enhances MgO's photoactivity and stability simultaneously. Such co-enhancement is attributed to the stable longitudinal-plasmon-free Au NPs, which provide robust hot electrons capable of overcoming the interband transition barrier (≈1.8 eV) to reach proton reduction potential for H2 generation. The demonstrated plasmonic defect nanosystems are expected to open a new avenue for developing highly endurable photoredox systems for the integration of multifunctionalities in energy conversion, environmental decontamination, and climate change mitigation.

13.
Tumour Biol ; 37(8): 11007-15, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26894601

RESUMO

The PI3K/Akt/mTOR axis in ovarian cancer is frequently activated and implicated in tumorigenesis. Specific targeting of this pathway is therefore an attractive therapeutic approach for ovarian cancer. However, ovarian cancer cells are resistant to PP242, a dual inhibitor of mTORC1 and mTORC2. Interestingly, blockage of GLS1 with a selective inhibitor, CB839, or siRNA dramatically sensitized the PP242-induced cell death, as evident from increased PARP cleavage. The anti-cancer activity of CB-839 and PP242 was abrogated by the addition of the TCA cycle product α-ketoglutarate, indicating the critical function of GLS1 in ovarian cancer cell survival. Finally, glutaminolysis inhibition activated apoptosis and synergistically sensitized ovarian cancer cells to priming with the mTOR inhibitor PP242. GLS1 inhibition significantly reduced phosphorylated STAT3 expression in ovarian cancer cells. These findings show that targeting glutamine addiction via GLS1 inhibition offers a potential novel therapeutic strategy to overcome resistance to PI3K/Akt/mTOR inhibition.


Assuntos
Resistencia a Medicamentos Antineoplásicos/fisiologia , Glutaminase/metabolismo , Neoplasias Ovarianas/metabolismo , Fator de Transcrição STAT3/metabolismo , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Benzenoacetamidas/farmacologia , Western Blotting , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Citometria de Fluxo , Técnicas de Silenciamento de Genes , Glutamina/metabolismo , Humanos , Indóis/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/farmacologia , Purinas/farmacologia , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/fisiologia , Serina-Treonina Quinases TOR/antagonistas & inibidores , Tiadiazóis/farmacologia
14.
Inorg Chem ; 55(6): 2765-70, 2016 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-26962880

RESUMO

High-quality α-MnSe nanocubes were successfully prepared for the first time by an effective hot injection synthesis strategy. This approach was simple but robust and had been applied to the controllable synthesis of different sizes and diverse morphologies of α-MnSe nanostructures. The crystal phases, compositions, and microstructures of these nanostructures had been systematically characterized with a series of techniques. As a proof-of-concept application, the as-prepared α-MnSe nanocubes were used as an anode material for a lithium ion battery, which exhibited superior rate ability and ultralong cycle stability in half-cell and full-cell tests. Importantly, the phase transition from α-MnSe to ß-MnSe during the electrochemical process was proved by ex situ X-ray diffraction and selected area electron diffraction. The excellent electrochemical performance of α-MnSe endowed its potential as an anode material candidate for high performance lithium storage.

15.
Chemistry ; 21(34): 11954-60, 2015 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-26100433

RESUMO

Various lanthanide oxides (Sm2 O3 and Gd2 O3 ) nanostructures were synthesized by a facile hydrothermal method. The loss of surfactants on the nanocrystals surface, followed by the resultant assembly is responsible for the formation of ultrathin nanosheets. Owing to strong surface effects, the different morphologies of the Sm2 O3 :5 % Eu and Gd2 O3 :5 % Eu nanocrystals present unique photoluminescence properties. As a proof-of-concept application, the as-obtained Sm2 O3 and Gd2 O3 ultrathin nanosheets exhibit promising pH-controlled anticancer drug-delivery behavior.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Gadolínio/química , Elementos da Série dos Lantanídeos/química , Nanopartículas/química , Nanoestruturas/química , Óxidos/síntese química , Antineoplásicos/química , Sistemas de Liberação de Medicamentos , Gadolínio/metabolismo , Concentração de Íons de Hidrogênio , Luminescência , Óxidos/química , Tamanho da Partícula , Samário/química , Propriedades de Superfície
16.
Small ; 10(22): 4727-34, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25302745

RESUMO

Tetrapod-shaped CdS colloidal nanocrystals are synthesized using a facile, phosphine-free synthesis approach at low temperature. The arm length and diameter of CdS tetrapods can be easily tuned by using different source of sulphureous precursors, i.e., sulfur powder, thioacetamide, and sodium diethyldithiocarbamate. Moreover, the growth of Au nanoparticles onto CdS to form metal-semiconductor hybrid nanocrystals is also demonstrated. The tetrapod-shaped CdS nanocrystals exhibit strong arm-diameter-dependent absorption and photoluminescence characteristics. Importantly, the as-obtained CdS tetrapods exhibit promising photocatalytic activity for the water-splitting reaction in photoelectrochemical cells.


Assuntos
Compostos de Cádmio/química , Temperatura Baixa , Ouro/química , Nanopartículas Metálicas/química , Fosfinas/química , Sulfetos/química , Coloides , Microscopia Eletrônica de Transmissão
17.
Materials (Basel) ; 17(7)2024 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-38611996

RESUMO

Due to its inherent high hardness, strength, and plasticity, tantalum-tungsten (Ta-W) alloy poses a considerable challenge in machining, resulting in pronounced tool wear, diminished tool lifespan, and suboptimal surface quality. This study undertook experiments utilizing uncoated carbide tools, TiAlN-coated carbide tools, and AlTiN-coated carbide tools for machining Ta-2.5W alloy. The investigation delved into the intricacies of surface temperature, tool longevity, and the distinctive wear characteristics under varying coating materials and cutting parameters. Concurrently, a comprehensive exploration of the wear mechanisms affecting the tools was conducted. Among the observed wear modes, flank wear emerged as the predominant issue for turning tools. Across all three tool types, adhesive wear and diffusion wear were identified as the principal wear mechanisms, with the TiAlN-coated tools displaying a reduced level of wear compared to their AlTiN-coated counterparts. The experimental findings conclusively revealed that TiAlN-coated carbide tools exhibited an extended tool lifespan in comparison to uncoated carbide tools and AlTiN-coated carbide tools, signifying superior cutting performance.

18.
J Colloid Interface Sci ; 656: 168-176, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-37989050

RESUMO

The manipulation of oxygen vacancies (OVs) in metal oxides has progressively emerged as a versatile strategy for improving their catalytic performance. In this study, we aim to enhance the oxygen evolution reaction (OER) performance of cerium oxide (CeO2) by doping heteroatoms (Fe, Co, Ni) to generate additional OVs. We systematically analyzed both the morphology and electronic structure of the obtained CeO2 catalysts. The experimental results revealed the self-assembly of two-dimensional (2D) CeO2 nanosheets, with an approximate thickness of ∼1.7 nm, into 2D nanosheet assemblies (NSAs). Moreover, the incorporation of heteroatoms into the CeO2 matrix promoted the formation of OVs, resulting in a significant enhancement of the OER performance of CeO2. Among them, the Co-doped CeO2 NSAs sample displayed the highest activity and durability, with almost negligible activity loss during extended operating periods. The roles of heteroatom doping in improving OER activity were explored by DFT calculations. The produced OVs improve the adsorption of hydroxyl groups (OH-), promote the deprotonation process, and increase more active sites. These findings suggest that doping CeO2 with heteroatoms is a promising strategy for improving electrocatalytic OER activity, with great potential for the development of clean energy technologies, including but not limited to water splitting and fuel cells.

19.
Talanta ; 270: 125563, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38134815

RESUMO

Colorectal cancer (CRC) remains a significant contributor to the global mortality rate, and a single biomarker cannot meet the specificity required for CRC screening. To this end, we developed a multiplexed, pump-free surface-enhanced Raman scattering (SERS) microfluidic chip (LoC-SERS) using a one-step recognition release mechanism; the aptamer-functionalized novel Au nanocrown array (AuNCA) was used as the detection element embedded in the detection zone of the platform for rapid and specific detection of protein markers in multiple samples simultaneously. Here, the corresponding aptamer specifically captured the protein marker, causing the complementary strand of the aptamer carrying the Raman signal molecule to be shed, reducing the SERS signal. Based on this platform, sensitive and specific detection of the target can be accomplished within 15 min with detection limits of 0.031 pg/mL (hnRNP A1) and 0.057 pg/mL (S100P). Meanwhile, the platform was consistent with ELISA results when used to test clinical. By substituting different aptamers, this platform can provide a new solution for the rapid and sensitive detection of protein markers, which has promising applications in future disease detection.


Assuntos
Aptâmeros de Nucleotídeos , Nanopartículas Metálicas , Neoplasias , Biomarcadores Tumorais , Proteínas , Análise Espectral Raman/métodos , Ouro , Limite de Detecção
20.
ACS Nano ; 18(4): 3801-3813, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38236141

RESUMO

Sodium-ion batteries (SIBs) have been extensively studied owing to the abundance and low-price of Na resources. However, the infeasibility of graphite and silicon electrodes in sodium-ion storage makes it urgent to develop high-performance anode materials. Herein, α-MnSe nanorods derived from δ-MnO2 (δ-α-MnSe) are constructed as anodes for SIBs. It is verified that α-MnSe will be transferred into ß-MnSe after the initial Na-ion insertion/extraction, and δ-α-MnSe undergoes typical conversion mechanism using a Mn-ion for charge compensation in the subsequent charge-discharge process. First-principles calculations support that Na-ion migration in defect-free α-MnSe can drive the lattice distortion to phase transition (alpha → beta) in thermodynamics and dynamics. The formed ß-MnSe with robust lattice structure and small Na-ion diffusion barrier boosts great structure stability and electrochemical kinetics. Hence, the δ-α-MnSe electrode contributes excellent rate capability and superior cyclic stability with long lifespan over 1000 cycles and low decay rate of 0.0267% per cycle. Na-ion full batteries with a high energy density of 281.2 Wh·kg-1 and outstanding cyclability demonstrate the applicability of δ-α-MnSe anode.

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