Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 77
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Nat Mater ; 22(5): 591-598, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37012436

RESUMO

Large spin-orbit torques (SOTs) generated by topological materials and heavy metals interfaced with ferromagnets are promising for next-generation magnetic memory and logic devices. SOTs generated from y spin originating from spin Hall and Edelstein effects can realize field-free magnetization switching only when the magnetization and spin are collinear. Here we circumvent the above limitation by utilizing unconventional spins generated in a MnPd3 thin film grown on an oxidized silicon substrate. We observe conventional SOT due to y spin, and out-of-plane and in-plane anti-damping-like torques originated from z spin and x spin, respectively, in MnPd3/CoFeB heterostructures. Notably, we have demonstrated complete field-free switching of perpendicular cobalt via out-of-plane anti-damping-like SOT. Density functional theory calculations show that the observed unconventional torques are due to the low symmetry of the (114)-oriented MnPd3 films. Altogether our results provide a path toward realization of a practical spin channel in ultrafast magnetic memory and logic devices.

2.
Inorg Chem ; 63(6): 2997-3004, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38291727

RESUMO

The construction of low-cost and highly efficient oxygen evolution electrocatalysts is paramount for clean and sustainable hydrogen energy. In recent years, metal-organic framework (MOF) OER electrocatalysts have attracted tremendous research attention. Herein, we report a simple and facile strategy to construct bimetallic MOFs (named CoMn0.01) for enhancing OER catalytic performance. Significantly, CoMn0.01 exhibited remarkable OER activity (255 mV at 10 mA cm-2) and a low Tafel slope of 66 mV dec-1, superior to those of commercial benchmark electrocatalysts (RuO2, 352 mV, 178 mV dec-1). Besides, the catalyst demonstrated outstanding longevity for 144 h at a current density of 100 mA cm -2. Mn doping can regulate the electronic structure of Co MOFs, which optimizes charge transfer capability and improves conductivity.

3.
J Clin Nurs ; 33(2): 740-751, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37888145

RESUMO

AIMS AND OBJECTIVES: This study aimed to describe the knowledge, attitudes and practices (KAP) of nurses in implementing advance directives (ADs) for older patients and analyze the influencing factors before the establishment of the first advance directives act in China. DESIGN: Multicenter cross-sectional survey. The standards for reporting the STROBE checklist are used. METHODS: This cross-sectional study developed a self-designed structured questionnaire to assess nurses' knowledge, attitudes and practices about ADs. Nurses were recruited by stratified random sampling through the Nursing Departments of 12 hospitals in southwest China and were asked to fill out the questionnaire face to face about knowledge, attitudes and practices. Data were analyzed following descriptive statistics, rank-sum test and multiple linear regression. RESULTS: This study included 950 nurses. The study found that nurses were extremely supportive of ADs. Unmarried nurses had better knowledge of ADs than married ones. Nevertheless, there was a discrepancy between the participants' knowledge, attitude and practice. The participants' practice was lower (4.3%) compared with their attitude (81.9%) and knowledge (42.2%). Knowledge on, attitudes towards and standardized procedures for ADs in the workplace affected nursing practice. CONCLUSIONS: The study recommends that courses on ADs and appropriate support from medical institutions should be provided to nurses to increase their knowledge and confidence in implementing ADs. Healthcare professionals should be sufficiently equipped to implement ADs and handle their execution appropriately to provide adequate end-of-life care corresponding to patients' wishes. RELEVANCE TO CLINICAL PRACTICE: The study results inform rich insights as it discusses the numerous interrelating factors influencing these three fundamental aspects that affect the success of any AD policy by surveying the knowledge, attitudes and practices of clinical nurses. Furthermore, our results hint at distinct areas of improvement in the nursing practice to facilitate the wider implementation and acceptance of ADs in China. PATIENT OR PUBLIC CONTRIBUTION: This study involved no patient.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Enfermeiras e Enfermeiros , Humanos , Estudos Transversais , Competência Clínica , Diretivas Antecipadas , Inquéritos e Questionários , Atitude do Pessoal de Saúde
4.
Nano Lett ; 23(9): 3781-3787, 2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37115910

RESUMO

van der Waals (vdW) assembly of two-dimensional (2D) materials allows polar layer stacking to realize novel properties switchable by the induced electric polarization. Here, based on symmetry analyses and density-functional calculations, we explore the emergence of the anomalous Hall effect (AHE) in antiferromagnetic MnBi2Te4 films assembled by polar layer stacking. We demonstrate that breaking P̂T̂ symmetry in an MnBi2Te4 bilayer produces a magnetoelectric effect and a spontaneous AHE switchable by electric polarization. We find that reversible polarization at one of the interfaces in a three-layer MnBi2Te4 film drives a metal-insulator transition, as well as switching between the AHE and quantum AHE (QAHE). Finally, we predict that engineering interlayer polarization in a three-layer MnBi2Te4 film allows converting MnBi2Te4 from a trivial insulator to a Chern insulator. Overall, our work emphasizes the topological properties in 2D vdW antiferromagnets induced by polar layer stacking, which do not exist in a bulk material.

5.
Zhongguo Zhong Yao Za Zhi ; 49(5): 1327-1334, 2024 Mar.
Artigo em Zh | MEDLINE | ID: mdl-38621980

RESUMO

This study aims to investigate whether baicalin induces ferroptosis in HepG2 cells and decipher the underlying mechanisms based on network pharmacology and cell experiments. HepG2 cells were cultured in vitro and the cell viability was detected by the cell counting kit-8(CCK-8). The transcriptome data of hepatocellular carcinoma were obtained from the Cancer Genome Atlas(TCGA), and the ferroptosis gene data from FerrDb V2. The DEG2 package was used to screen the differentially expressed genes(DEGs), and the common genes between DEGs and ferroptosis genes were selected as the target genes that mediate ferroptosis to regulate hepatocellular carcinoma progression. The functions and structures of the target genes were analyzed by Gene Ontology(GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment with the thresholds of P<0.05 and |log_2(fold change)|>0.5. DCFH-DA probe was used to detect the changes in the levels of cellular reactive oxygen species(ROS) in each group. The reduced glutathione(GSH) assay kit was used to measure the cellular GSH level, and Fe~(2+) assay kit to determine the Fe~(2+) level. Real-time quantitative PCR(RT-PCR) was employed to measure the mRNA levels of glutathione peroxidase 4(GPX4) and solute carrier family 7 member 11(SLC7A11) in each group. Western blot was employed to determine the protein levels of GPX4, SLC7A11, phosphatidylinositol 3-kinase(PI3K), p-PI3K, protein kinase B(Akt), p-Akt, forkhead box protein O3a(FoxO3a), and p-FoxO3a in each group. The results showed that treatment with 200 µmol·L~(-1) baicalin for 48 h significantly inhibited the viability of HepG2 cells. Ferroptosis in hepatocellular carcinoma could be regulated via the PI3K/Akt signaling pathway. The cell experiments showed that baicalin down-regulated the expression of SLC7A11 and GPX4, lowered the GSH level, and increased ROS accumulation and Fe~(2+) production in HepG2 cells. However, ferrostatin-1, an ferroptosis inhibitor, reduced baicalin-induced ROS accumulation, up-regulated the expression of SLC7A11 and GPX4, elevated the GSH level, and decreased PI3K, Akt, and FoxO3a phosphorylation. In summary, baicalin can induce ferroptosis in HepG2 cells by inhibiting the ROS-mediated PI3K/Akt/FoxO3a pathway.


Assuntos
Carcinoma Hepatocelular , Ferroptose , Flavonoides , Neoplasias Hepáticas , Humanos , Proteínas Proto-Oncogênicas c-akt/genética , Fosfatidilinositol 3-Quinases/genética , Espécies Reativas de Oxigênio , Células Hep G2 , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Transdução de Sinais
6.
Phys Rev Lett ; 131(24): 246301, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38181146

RESUMO

Valleytronics is a research field utilizing a valley degree of freedom of electrons for information processing and storage. A strong valley polarization is critical for realistic valleytronic applications. Here, we predict a tunneling valley Hall effect (TVHE) driven by tilted Dirac fermions in all-in-one tunnel junctions based on a two-dimensional (2D) valley material. Different doping of the electrode and spacer regions in these tunnel junctions results in momentum filtering of the tunneling Dirac fermions, generating a strong transverse valley Hall current dependent on the Dirac-cone tilting. Using the parameters of an existing 2D valley material, we demonstrate that such a strong TVHE can host a giant valley Hall angle even in the absence of the Berry curvature. Finally, we predict that resonant tunneling can occur in a tunnel junction with properly engineered device parameters such as the spacer width and transport direction, providing significant enhancement of the valley Hall angle. Our work opens a new approach to generate valley polarization in realistic valleytronic systems.

7.
Phys Rev Lett ; 130(21): 216702, 2023 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-37295086

RESUMO

Ferromagnets are known to support spin-polarized currents that control various spin-dependent transport phenomena useful for spintronics. On the contrary, fully compensated antiferromagnets are expected to support only globally spin-neutral currents. Here, we demonstrate that these globally spin-neutral currents can represent the Néel spin currents, i.e., staggered spin currents flowing through different magnetic sublattices. The Néel spin currents emerge in antiferromagnets with strong intrasublattice coupling (hopping) and drive the spin-dependent transport phenomena such as tunneling magnetoresistance (TMR) and spin-transfer torque (STT) in antiferromagnetic tunnel junctions (AFMTJs). Using RuO_{2} and Fe_{4}GeTe_{2} as representative antiferromagnets, we predict that the Néel spin currents with a strong staggered spin polarization produce a sizable fieldlike STT capable of the deterministic switching of the Néel vector in the associated AFMTJs. Our work uncovers the previously unexplored potential of fully compensated antiferromagnets and paves a new route to realize the efficient writing and reading of information for antiferromagnetic spintronics.

8.
Langmuir ; 39(49): 17947-17958, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38038632

RESUMO

Developing a photocatalyst that can effectively utilize the full solar spectrum remains a high-priority objective in the ongoing pursuit of efficient light-to-chemical energy conversion. Herein, the ternary nanocomposite g-C3N4/RGO/W18O49 (CN/RGO/WO) was constructed and characterized by a variety of techniques. Remarkably, under the excitation of photon energies ranging from the ultraviolet (UV) to the near-infrared (NIR) region, the photocatalytic performance of the CN/RGO/WO nanocomposite exhibited a significant enhancement compared with single component g-C3N4 or W18O49 nanosheets for the degradation of methyl orange (MO). The MO photodegradation rate of the optimal CN/1.0 wt% RGO/45.0 wt% WO catalyst reached 0.816 and 0.027 min-1 under UV and visible light excitation, respectively. Even under low-energy NIR light, which is not sufficient to excite g-C3N4, the MO degradation rate can still reach 0.0367 h-1, exhibiting a significant enhancement than pure W18O49. The outstanding MO removal rate and stability were demonstrated by CN/RGO/WO nanocomposites, which arise from the synergistic effect of localized surface plasmon resonance effect induced by W18O49 under vis-NIR excitation and the Z-scheme nanoheterojunction of W18O49 and g-C3N4. In this work, we have exploited the great potential of integrating nonmetallic plasmonic nanomaterials and good conductor RGO to construct high-performance g-C3N4-based full-solar spectral broadband photocatalysts.

9.
Nano Lett ; 22(8): 3349-3355, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35380845

RESUMO

Magnetic skyrmions are chiral nanoscale spin textures which are usually induced by the Dzyaloshinskii-Moriya interaction (DMI). Recently, magnetic skyrmions have been observed in two-dimensional (2D) van der Waals (vdW) ferromagnetic materials, such as Fe3GeTe2. The electric control of skyrmions is important for their potential application in low-power memory technologies. Here, we predict that DMI and magnetic skyrmions in a Fe3GeTe2 monolayer can be controlled by ferroelectric polarization of an adjacent 2D vdW ferroelectric In2Se3. Based on density functional theory and atomistic spin-dynamics modeling, we find that the interfacial symmetry breaking produces a sizable DMI in a Fe3GeTe2/In2Se3 vdW heterostructure. We show that the magnitude of DMI can be controlled by ferroelectric polarization reversal, leading to creation and annihilation of skyrmions. Furthermore, we find that the sign of DMI in a In2Se3/Fe3GeTe2/In2Se3 heterostructure changes with ferroelectric switching reversing the skyrmion chirality. The predicted electrically controlled skyrmion formation may be interesting for spintronic applications.

10.
Cancer Cell Int ; 21(1): 640, 2021 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-34856991

RESUMO

BACKGROUND: Osteosarcoma (OS) metastasis is the most common cause of cancer-related mortality, however, no sufficient clinical biomarkers have been identified. In this study, we identified five genes to help predict metastasis at diagnosis. METHODS: We performed weighted gene co-expression network analysis (WGCNA) to identify the most relevant gene modules associated with OS metastasis. An important machine learning algorithm, the support vector machine (SVM), was employed to predict key genes for classifying the OS metastasis phenotype. Finally, we investigated the clinical significance of key genes and their enriched pathways. RESULTS: Eighteen modules were identified in WGCNA, among which the pink, red, brown, blue, and turquoise modules demonstrated good preservation. In the five modules, the brown and red modules were highly correlated with OS metastasis. Genes in the two modules closely interacted in protein-protein interaction networks and were therefore chosen for further analysis. Genes in the two modules were primarily enriched in the biological processes associated with tumorigenesis and development. Furthermore, 65 differentially expressed genes were identified as common hub genes in both WGCNA and protein-protein interaction networks. SVM classifiers with the maximum area under the curve were based on 30 and 15 genes in the brown and red modules, respectively. The clinical significance of the 45 hub genes was analyzed. Of the 45 genes, 17 were found to be significantly correlated with survival time. Finally, 5/17 genes, including ADAP2 (P = 0.0094), LCP2 (P = 0.013), ARHGAP25 (P = 0.0049), CD53 (P = 0.016), and TLR7 (P = 0.04) were significantly correlated with the metastatic phenotype. In vitro verification, western blotting, wound healing analyses, transwell invasion assays, proliferation assays, and colony formation assays indicated that ARHGAP25 promoted OS cell migration, invasion, proliferation, and epithelial-mesenchymal transition. CONCLUSION: We identified five genes, namely ADAP2, LCP2, ARHGAP25, CD53, and TLR7, as candidate biomarkers for the prediction of OS metastasis; ARHGAP25 inhibits MG63 OS cell growth, migration, and invasion in vitro, indicating that ARHGAP25 can serve as a promising specific and prognostic biomarker for OS metastasis.

11.
Phys Rev Lett ; 126(5): 057601, 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33605764

RESUMO

Ferroelectric tunnel junctions (FTJs), which consist of two metal electrodes separated by a thin ferroelectric barrier, have recently aroused significant interest for technological applications as nanoscale resistive switching devices. So far, most existing FTJs have been based on perovskite-oxide barrier layers. The recent discovery of the two-dimensional (2D) van der Waals ferroelectric materials opens a new route to realize tunnel junctions with new functionalities and nm-scale dimensions. Because of the weak coupling between the atomic layers in these materials, the relative dipole alignment between them can be controlled by applied voltage. This allows transitions between ferroelectric and antiferroelectric orderings, resulting in significant changes of the electronic structure. Here, we propose to realize 2D antiferroelectric tunnel junctions (AFTJs), which exploit this new functionality, based on bilayer In_{2}X_{3} (X=S, Se, Te) barriers and different 2D electrodes. Using first-principles density functional theory calculations, we demonstrate that the In_{2}X_{3} bilayers exhibit stable ferroelectric and antiferroelectric states separated by sizable energy barriers, thus supporting a nonvolatile switching between these states. Using quantum-mechanical modeling of the electronic transport, we explore in-plane and out-of-plane tunneling across the In_{2}S_{3} van der Waals bilayers, and predict giant tunneling electroresistance effects and multiple nonvolatile resistance states driven by ferroelectric-antiferroelectric order transitions. Our proposal opens a new route to realize nanoscale memory devices with ultrahigh storage density using 2D AFTJs.

12.
Phys Rev Lett ; 127(13): 136803, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34623838

RESUMO

The low in-plane symmetry in layered 1T'-ReS_{2} results in strong band anisotropy, while its manifestation in the electronic properties is challenging to resolve due to the lack of effective approaches for controlling the local current path. In this work, we reveal the giant transport anisotropy in monolayer to four-layer ReS_{2} by creating directional conducting paths via nanoscale ferroelectric control. By reversing the polarization of a ferroelectric polymer top layer, we induce a conductivity switching ratio of >1.5×10^{8} in the ReS_{2} channel at 300 K. Characterizing the domain-defined conducting nanowires in an insulating background shows that the conductivity ratio between the directions along and perpendicular to the Re chain can exceed 5.5×10^{4} in monolayer ReS_{2}. Theoretical modeling points to the band origin of the transport anomaly and further reveals the emergence of a flat band in few-layer ReS_{2}. Our work paves the path for implementing highly anisotropic 2D materials for designing novel collective phenomena and electron lensing applications.

13.
Int J Mol Sci ; 22(8)2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33920853

RESUMO

A self-nanoemulsifying drug delivery system (SNEDDS) was developed to enhance the absorption of heparin after oral administration, in which heparin was compounded with phospholipids to achieve better fat solubility in the form of heparin-phospholipid (HEP-Pc) complex. HEP-Pc complex was prepared using the solvent evaporation method, which increased the solubility of heparin in n-octanol. The successful preparation of HEP-Pc complex was confirmed by differential scanning calorimetry (DSC), Fourier-transform infrared (FT-IR) spectroscopy, NMR, and SEM. A heparin lipid microemulsion (HEP-LM) was prepared by high-pressure homogenization and characterized. HEP-LM can enhance the absorption of heparin after oral administration, significantly prolong activated partial thromboplastin time (APTT) and thrombin time (TT) in mice, and reduce fibrinogen (FIB) content. All these outcomes indicate that HEP-LM has great potential as an oral heparin formulation.


Assuntos
Sistemas de Liberação de Medicamentos , Emulsões/química , Heparina/farmacologia , Nanopartículas/química , Fosfolipídeos/química , Administração Oral , Animais , Anticoagulantes/farmacologia , Varredura Diferencial de Calorimetria , Heparina/administração & dosagem , Masculino , Camundongos , Nanopartículas/ultraestrutura , Tamanho da Partícula , Espectroscopia de Prótons por Ressonância Magnética , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Phys Rev Lett ; 124(6): 067203, 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32109084

RESUMO

Antiferromagnetic (AFM) spintronics exploits the Néel vector as a state variable for novel spintronic devices. Recent studies have shown that the fieldlike and antidamping spin-orbit torques (SOTs) can be used to switch the Néel vector in antiferromagnets with proper symmetries. However, the precise detection of the Néel vector remains a challenging problem. In this Letter, we predict that the nonlinear anomalous Hall effect (AHE) can be used to detect the Néel vector in most compensated antiferromagnets supporting the antidamping SOT. We show that the magnetic crystal group symmetry of these antiferromagnets combined with spin-orbit coupling produce a sizable Berry curvature dipole and hence the nonlinear AHE. As a specific example, we consider the half-Heusler alloy CuMnSb, in which the Néel vector can be switched by the antidamping SOT. Based on density-functional theory calculations, we show that the nonlinear AHE in CuMnSb results in a measurable Hall voltage under conventional experimental conditions. The strong dependence of the Berry curvature dipole on the Néel vector orientation provides a new detection scheme of the Néel vector based on the nonlinear AHE. Our predictions enrich the material platform for studying nontrivial phenomena associated with the Berry curvature and broaden the range of materials useful for AFM spintronics.

15.
Br J Nutr ; 123(5): 481-488, 2020 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-31623699

RESUMO

The present study was conducted to evaluate the effects of glucose, soya oil or glutamine on jejunal morphology, protein metabolism and protein expression of the mammalian target of rapamycin complex 1 (mTORC1) signalling pathway in jejunal villus or crypt compartment of piglets. Forty-two 21 d-weaned piglets were randomly allotted to one of the three isoenergetic diets formulated with glucose, soya oil or glutamine for 28 d. On day 14 or 28, the proteins in crypt enterocytes were analysed with isobaric tags for relative and absolute quantification and proteins involved in mTORC1 signalling pathway in villus or crypt compartment cells were determined by Western blotting. Our results showed no significant differences (P > 0·05) in jejunal morphology among the three treatments on day 14 or 28. The differentially expressed proteins mainly took part in a few network pathways, including antimicrobial or inflammatory response, cell death and survival, digestive system development and function and carbohydrate metabolism. On day 14 or 28, there were higher protein expression of eukaryotic initiation factor-4E binding protein-1 in jejunal crypt compartment of piglets supplemented with glucose or glutamine compared with soya oil. On day 28, higher protein expression of phosphor-mTOR in crypt compartment was observed in piglets supplemented with glucose compared with the soya oil. In conclusion, the isoenergetic glucose, soya oil or glutamine did not affect the jejunal morphology of piglets; however, they had different effects on the protein metabolism in crypt compartment. Compared with soya oil, glucose or glutamine may be better energy supplies for enterocytes in jejunal crypt compartment.


Assuntos
Suplementos Nutricionais , Glucose/farmacologia , Glutamina/farmacologia , Óleo de Soja/farmacologia , Serina-Treonina Quinases TOR/metabolismo , Animais , Enterócitos/metabolismo , Jejuno/metabolismo , Transdução de Sinais/efeitos dos fármacos , Suínos , Desmame
16.
Phys Rev Lett ; 122(7): 077203, 2019 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-30848649

RESUMO

Topological antiferromagnetic (AFM) spintronics is an emerging field of research, which exploits the Néel vector to control the topological electronic states and the associated spin-dependent transport properties. A recently discovered Néel spin-orbit torque has been proposed to electrically manipulate Dirac band crossings in antiferromagnets; however, a reliable AFM material to realize these properties in practice is missing. In this Letter, we predict that room-temperature AFM metal MnPd_{2} allows the electrical control of the Dirac nodal line by the Néel spin-orbit torque. Based on first-principles density functional theory calculations, we show that reorientation of the Néel vector leads to switching between the symmetry-protected degenerate state and the gapped state associated with the dispersive Dirac nodal line at the Fermi energy. The calculated spin Hall conductivity strongly depends on the Néel vector orientation and can be used to experimentally detect the predicted effect using a proposed spin-orbit torque device. Our results indicate that AFM Dirac nodal line metal MnPd_{2} represents a promising material for topological AFM spintronics.

17.
Sheng Li Xue Bao ; 71(4): 537-546, 2019 Aug 25.
Artigo em Zh | MEDLINE | ID: mdl-31440750

RESUMO

Intermittent hypoxia (IH) has preventive and therapeutic effects on hypertension, myocardial infarction, cerebral ischemia and depression, but its effect on post-traumatic stress disorder (PTSD) has not been known. In this study, we used inescapable electric foot shock combined with context recapture to build PTSD mouse model. The levels of fear and anxiety were valued by the open field, the elevated plus maze (EPM) and the fear conditioning tests; the level of spatial memory was valued by Y maze test; the number of Fos positive neurons in hippocampus, amygdala and medial prefrontal cortex was valued by immunohistochemical staining; and the protein expressions of hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and brain derived neurotrophic factor (BDNF) in these brain area were valued by Western blot. The results showed that IH and model (foot shock) had an interaction on percentage of entering open arms (OE%) in EPM and freezing time and the number of fecal pellets in fear conditioning test. IH increased OE% in EPM and reduced the freezing time and the number of fecal pellets in fear conditioning test in PTSD model mice. At the same time, IH reduced the number of Fos positive neurons in the hippocampus, amygdala and medial prefrontal cortex of PTSD model mice, and increased the protein expression levels of HIF-1α, VEGF and BDNF in these brain tissues. In conclusion, IH pretreatment can relieve fear and anxiety behavior in post-traumatic stress model mice, suggesting that IH may be an effective means of preventing PTSD.


Assuntos
Ansiedade/terapia , Medo , Hipóxia , Transtornos de Estresse Pós-Traumáticos/terapia , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Camundongos , Fator A de Crescimento do Endotélio Vascular/metabolismo
18.
Phys Chem Chem Phys ; 20(36): 23301-23310, 2018 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-30175345

RESUMO

Theoretical study of the electronic structures of protein is a fundamental challenge in computational biochemistry due to the large size of the systems. The electronic structure of a protein is important for some of the important protein functionalities, such as photosynthesis. In this study, we explored the charge-patching method to calculate the electronic structure of polypeptides. This method generates the charge densities of the systems by patching the charge motifs calculated from small prototype systems. The method was tested on a range of polypeptides, including the glycine polypeptide in 27-ribbon, α-helix, 310-helix, and ß-strand structures. After the charge density profiles of these systems were obtained, the electronic structures of these glycine polypeptides were further calculated based on density functional theory (DFT) using a folded-spectrum method. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were analyzed and compared with conventional direct DFT calculations. The charge-patching method results were found to be in good agreement with the directed DFT results.


Assuntos
Peptídeos/química , Teoria Quântica , Elétrons , Conformação Proteica
19.
J Nanosci Nanotechnol ; 18(12): 8216-8224, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30189940

RESUMO

To enhance solar energy utilization efficiency, goal-directed design of architectures by combining nanocomponents of radically different properties, such as plasmonic, upconversion, and photocatalytic properties may provide a promising method to utilize the most energy in sunlight. In this work, a new strategy was adopted to fabricate a series of plasmonic Ag nanoparticles decorated GdF3:Yb3+, Er3+, Tm3+-core@porous-TiO2-shell ellipsoids, which exhibit high surface area, good stability, broadband absorption from ultraviolet to near infrared, and excellent photocatalytic activity. The results showed that photocatalytic activities of the as-obtained photocatalysts was higher than that of pure GdF3:Yb3+, Er3+, Tm3+ and GdF3:Yb3+, Er3+, Tm3+@TiO2 samples through the comparison of photodegradation rates of methyl orange under UV, visible, and NIR irradiation. The possible photocatalytic mechanism indicates that hydroxyl radicals and superoxide radical play a pivotal role in the photodegradation. Furthermore, the materials also showed exceptionally high stability and reusability under UV, visible, and NIR irradiation. All these results reveal that core-shell hierarchical ellipsoids exhibit great prospects for developing efficient solar photocatalysts.

20.
J Nanosci Nanotechnol ; 18(12): 8302-8306, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30189951

RESUMO

A hard template strategy is developed to fabricate the LuBO3: Eu3+/Tb3+ hollow microspheres using a novel multi-step transformation synthetic route for the first time with polystyrene (PS) spheres as the template, followed by the combination of a facile homogeneous precipitation method, an ion-exchange process, and a calcination process. The results show that the as-obtained LuBO3: Eu3+/Tb3+ hollow spheres have a uniform morphology with an average diameter of 1.8 µm and shell thickness of about 80 nm. When used as luminescent materials, the emission colors of LuBO3: Eu3+/Tb3+ samples can be tuned from red, through orange, yellow and green-yellow, to green by simply adjusting the relative doping concentrations of the activator ions under the excitation of ultraviolet (UV) light, which might have potential applications in the field such as light display systems and optoelectronic devices.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA