Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Biochem Biophys Res Commun ; 705: 149742, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38460438

RESUMEN

l-norleucine, an isomer of leucine, stimulates the anabolic process of insulin. However, it is not known if and how it improves insulin sensitivity and insulin resistance. This experiment describes the generation of an insulin resistance model using high glucose-induced cells and the administration of 1.0 mmol/L l-norleucine for 48 h, to observe the effects on metabolism and gene expression in skeletal muscle cells. The results showed that l-norleucine significantly increased mitochondrial ATP content, decreased the amount of reactive oxygen species (ROS) and promoted the expression of mitochondrial generation-related genes TFAM, AMPK, PGC-1α in cells under high glucose treatment; at the same time, l-norleucine also increased glucose uptake, suggesting that l-norleucine increased insulin sensitivity and improved insulin resistance. This study suggesting that l-norleucine improves insulin resistance by ameliorating oxidative stress damage of mitochondria, improving mitochondrial function, and improving insulin sensitivity in skeletal muscle cell caused by high glucose, rather than by altering mitochondrial efficiency.


Asunto(s)
Resistencia a la Insulina , Humanos , Resistencia a la Insulina/fisiología , Músculo Esquelético/metabolismo , Mitocondrias/metabolismo , Insulina/metabolismo , Norleucina/metabolismo , Norleucina/farmacología , Glucosa/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Mitocondrias Musculares/metabolismo
2.
J Funct Biomater ; 14(12)2023 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-38132817

RESUMEN

In biomaterial-based bone tissue engineering, optimizing scaffold structure and composition remains an active field of research. Additive manufacturing has enabled the production of custom designs in a variety of materials. This study aims to improve the design of calcium-phosphate-based additively manufactured scaffolds, the material of choice in oral bone regeneration, by using a combination of in silico and in vitro tools. Computer models are increasingly used to assist in design optimization by providing a rational way of merging different requirements into a single design. The starting point for this study was an in-house developed in silico model describing the in vitro formation of neotissue, i.e., cells and the extracellular matrix they produced. The level set method was applied to simulate the interface between the neotissue and the void space inside the scaffold pores. In order to calibrate the model, a custom disk-shaped scaffold was produced with prismatic canals of different geometries (circle, hexagon, square, triangle) and inner diameters (0.5 mm, 0.7 mm, 1 mm, 2 mm). The disks were produced with three biomaterials (hydroxyapatite, tricalcium phosphate, and a blend of both). After seeding with skeletal progenitor cells and a cell culture for up to 21 days, the extent of neotissue growth in the disks' canals was analyzed using fluorescence microscopy. The results clearly demonstrated that in the presence of calcium-phosphate-based materials, the curvature-based growth principle was maintained. Bayesian optimization was used to determine the model parameters for the different biomaterials used. Subsequently, the calibrated model was used to predict neotissue growth in a 3D gyroid structure. The predicted results were in line with the experimentally obtained ones, demonstrating the potential of the calibrated model to be used as a tool in the design and optimization of 3D-printed calcium-phosphate-based biomaterials for bone regeneration.

3.
Front Nutr ; 10: 1288837, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37841409

RESUMEN

[This corrects the article DOI: 10.3389/fnut.2022.915865.].

4.
Chem Commun (Camb) ; 59(89): 13348-13351, 2023 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-37872783

RESUMEN

A TTPP probe was developed to distinguish G-quadruplexes (G4s) from other nucleic acid topologies through longer fluorescence lifetimes and higher quantum yields. In fluorescence lifetime imaging microscopy, TTPP enabled the visualization of cytoplasmic G4s in live cells, and showed the potential to detect cell apoptosis and ferroptosis by tracking cytoplasmic G4s.


Asunto(s)
G-Cuádruplex , Ácidos Nucleicos , Colorantes Fluorescentes , Citoplasma , Citosol
5.
Int J Mol Sci ; 24(18)2023 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-37762513

RESUMEN

Salicylic acid (SA) serves as a pivotal plant hormone involved in regulating plant defense mechanisms against biotic stresses, but the extent of its biological significance in relation to peanut resistance is currently lacking. This study elucidated the involvement of salicylic acid (SA) in conferring broad-spectrum disease resistance in peanuts through the experimental approach of inoculating SA-treated leaves. In several other plants, the salicylate hydroxylase genes are the typical susceptible genes (S genes). Here, we characterized two SA hydroxylase genes (AhS5H1 and AhS5H2) as the first S genes in peanut. Recombinant AhS5H proteins catalyzed SA in vitro, and showed SA 5-ydroxylase (S5H) activity. Overexpression of AhS5H1 or AhS5H2 decreased SA content and increased 2,5-DHBA levels in Arabidopsis, suggesting that both enzymes had a similar role in planta. Moreover, overexpression of each AhS5H gene increased susceptibility to Pst DC3000. Analysis of the transcript levels of defense-related genes indicated that the expression of AhS5H genes, AhNPR1 and AhPR10 was simultaneously induced by chitin. Overexpression of each AhS5H in Arabidopsis abolished the induction of AtPR1 or AtPR2 upon chitin treatment. Eventually, AhS5H2 expression levels were highly correlated with SA content in different tissues of peanut. Hence, the expression of AhS5H1 and AhS5H2 was tissue-specific.


Asunto(s)
Arabidopsis , Arachis , Arachis/genética , Arabidopsis/genética , Quitina , Resistencia a la Enfermedad/genética , Ácido Salicílico/farmacología
6.
Angew Chem Int Ed Engl ; 62(44): e202312170, 2023 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-37710398

RESUMEN

Regulating autophagy to control the homeostatic recycling process of cancer cells is a promising anticancer strategy. Golgi apparatus is a substrate of autophagy but the Golgi-autophagy (Golgiphagy) mediated antitumor pathway is rarely reported. Herein, we have developed a novel Golgi-targeted platinum (II) complex Pt3, which is ca. 20 times more cytotoxic to lung carcinoma than cisplatin and can completely eliminate tumors after intratumoral administration in vivo. Its nano-encapsulated system for tail vein administration also features a good anti-tumor effect. Mechanism studies indicate that Pt3 induces substantial Golgi stress, indicated by the fragmentation of Golgi structure, down-regulation of Golgi proteins (GM130, GRASP65/55), loss of Golgi-dependent transport and glycosylation. This triggers Golgiphagy but blocks the subsequent fusion of autophagosomes with lysosomes, that is a dual role in autophagy regulation, resulting in loss of proteostasis and apoptotic cell death. As far as we know, Pt3 is the first Golgi-targeted Pt complex that can trigger Golgi stress-mediated dual-regulation of autophagic flux and autophagy-apoptosis crosstalk for highly efficient cancer therapy.


Asunto(s)
Antineoplásicos , Neoplasias , Platino (Metal)/farmacología , Autofagia , Aparato de Golgi/metabolismo , Cisplatino/farmacología , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Antineoplásicos/metabolismo , Neoplasias/metabolismo
7.
Artículo en Inglés | MEDLINE | ID: mdl-37141070

RESUMEN

In order to improve the traditional common space pattern (CSP) algorithm pattern in EEG feature extraction, this study proposes a feature extraction method of EEG signals based on permutation conditional mutual information common space pattern (PCMICSP), which used the sum of the permutation condition mutual information matrices of each lead to replacing the mixed spatial covariance matrix in the traditional CSP algorithm, and its eigenvectors and eigenvalues are used to construct a new spatial filter. Then the spatial features in the different time domains and frequency domains are combined to construct the two-dimensional pixel map, Finally, a convolutional neural network (CNN) is used for binary classification. The EEG signals of 7 community elderly before and after spatial cognitive training in virtual reality (VR) scenes were used as the test data set. The average classification accuracy of the PCMICSP algorithm for pre-test and post-test EEG signals is 98%, which was higher than that of CSP based on CMI (conditional mutual information), CSP based on MI (mutual information), and traditional CSP in the combination of four frequency bands. Compared with the traditional CSP method, PCMICSP can be used as a more effective method to extract the spatial features of EEG signals. Therefore, this paper provides a new approach to solving the strict linear hypothesis of CSP and can be used as a valuable biomarker for the spatial cognitive evaluation of the elderly in the community.


Asunto(s)
Interfaces Cerebro-Computador , Procesamiento de Señales Asistido por Computador , Humanos , Anciano , Electroencefalografía/métodos , Algoritmos , Cognición , Imaginación
8.
Plant Dis ; 107(8): 2506-2508, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36774571

RESUMEN

Streptomyces atratus PY-1 exhibited promising antimicrobial properties; in particular, it is highly inhibitory to Plasmopara viticola, which causes downy mildew of grape. It is very necessary to carry out systematic and in-depth research on the PY-1 strain for the improvement, application, and promotion of biocontrol agents. The PY-1 genome was fully sequenced and assembled. We present the draft genome sequence of PY-1, with a size of 9, 254, and 781 bp. Preliminary analysis on the PY-1 genome sequence shows that at least 35 gene clusters are involved in the biosynthesis of polyketides, terpenes, and nonribosomally synthesized peptides.


Asunto(s)
Antiinfecciosos , Oomicetos , Peronospora , Enfermedades de las Plantas/genética , Oomicetos/genética , Antiinfecciosos/farmacología
9.
Angew Chem Int Ed Engl ; 62(8): e202216917, 2023 02 13.
Artículo en Inglés | MEDLINE | ID: mdl-36546893

RESUMEN

Zinc homeostatic medicine is of great potential for cancer chemo-immunotherapy; however, there are few reports on antitumor compounds that can trigger Zn2+ -mediated immune responses. In this work, we developed a novel cyclometalated PtIV -terthiophene complex, Pt3, that not only induces DNA damage and cellular metabolism dysregulation, but also disrupts zinc homeostasis as indicated by the abnormal transcriptional level of zinc regulatory proteins, excess accumulation of Zn2+ in cytoplasm, and down-regulation of metallothioneins (MTs), which further caused redox imbalance. The simultaneous disruption of zinc and redox homeostasis in response to Pt3 treatment activated gasdermin-D mediated pyroptosis accompanied by cytoskeleton remodeling, thus releasing pro-inflammatory cytokines to promote dendritic cell (DC) maturation and T cell tumor-infiltration, eventually eliminating both primary and distant tumors in vivo. As far as we know, this is the first metal complex that can regulate zinc homeostasis to activate antitumor immunity.


Asunto(s)
Platino (Metal) , Zinc , Zinc/metabolismo , Homeostasis , Metalotioneína/genética
10.
Chem Sci ; 13(38): 11360-11367, 2022 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-36320579

RESUMEN

Regulation of tumor hypoxia and redox homeostasis is a promising strategy for cancer therapy. Nanocatalytic medicine has played more and more important roles in this field because it can cleverly convert the efficiency and selectivity of catalysis into high therapeutic efficiency. Herein, we developed a platinum(iv)-ruthenium hybrid prodrug, named as Pt-Ru, for efficient chemo-catalytic synergistic therapy of hypoxic tumors. The ruthenium hybridization endowed the Pt(iv) prodrug with multi-enzyme catalytic activity, that is, mimicking catalase (CAT) to generate O2 in situ, mimicking peroxidase (POD) to produce reactive oxygen species, and mimicking glutathione peroxidase (GPx) to deplete GSH, thus effectively overcoming tumor hypoxia and cisplatin resistance. As a result, Pt-Ru treatment led to a superior anticancer efficacy to cisplatin both in vitro and in vivo. This work suggested redox homeostasis regulation as a tantalizing angle for developing the next generation of platinum drugs.

11.
Front Nutr ; 9: 915865, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35967814

RESUMEN

Natural plant herbs have many active compounds to prevent poultry diseases and improve poultry products. However, most herbs are supplied for human medicine. Thus, for economic and sustainable development purposes, the dregs of Cardamine hupingshanensis (DCH) were developed as a feed additive to improve the egg quality of laying hens in this work. Results showed that the contents of selenium in hen serum and eggs were increased under DCH feeding. Subsequently, DCH also promotes the antioxidant capacity and immunity of laying hens through the increase of superoxide dismutase (SOD), catalase (CAT), and immunoglobulin G (IgG) by ELISA detection. Finally, production performance and egg quality were further graded by monitoring the product condition and scoring the indexes of egg quality, which also displayed that DCH as a feed additive significantly improved the egg quality by enhancing yolk color, eggshell thickness, and egg shape index.

12.
Chem Sci ; 13(28): 8371-8379, 2022 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-35919711

RESUMEN

Thrombin Binding Aptamer (TBA) is a monomolecular well-defined two G-tetrad antiparallel G-quadruplex DNA that inhibits the activity of human α-thrombin. In this report, we synthesized a quasi-cross-shaped platinum(ii) compound (L'2LPt) with one cyclometalated and two carbene ligands. We found L'2LPt has selective affinity to bind the TBA G-quadruplex. A fibrinogen clotting assay revealed that L'2LPt can abrogate the inhibitory activity of TBA against thrombin. We solved the 1 : 1 L'2LPt-TBA complex structure by NMR, which revealed a unique self-adaptive property of L'2LPt upon binding to TBA. In the complex, a carbene ligand of L'2LPt rotates to pair with the cyclometalated ligand to form a plane stacking over half of the TBA G-tetrad and covered by lateral TT loops. It is notable that the heavy atom Pt stays out of the G-tetrad. Meanwhile, the other carbene ligand remains relatively perpendicular and forms a hydrogen bond with a guanine to anchor the L'2LPt position. This structure exhibits a quasi-cross-shaped Pt(ii) compound bound to the G-quadruplex with an unusual "wall-mounted" binding mode. Our structures provide insights into the specific recognition of antiparallel G-quadruplex DNA by a self-adaptive Pt(ii) compound and useful information for the design of selective G-quadruplex targeting non-planar molecules.

13.
Int J Mol Sci ; 23(3)2022 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-35163275

RESUMEN

Rice plants contain high basal levels of salicylic acid (SA), but some of their functions remain elusive. To elucidate the importance of SA homeostasis in rice immunity, we characterized four rice SA hydroxylase genes (OsSAHs) and verified their roles in SA metabolism and disease resistance. Recombinant OsSAH proteins catalyzed SA in vitro, while OsSAH3 protein showed only SA 5-hydroxylase (SA5H) activity, which was remarkably higher than that of other OsSAHs that presented both SA3H and SA5H activities. Amino acid substitutions revealed that three amino acids in the binding pocket affected SAH enzyme activity and/or specificity. Knockout OsSAH2 and OsSAH3 (sahKO) genes conferred enhanced resistance to both hemibiotrophic and necrotrophic pathogens, whereas overexpression of each OsSAH gene increased susceptibility to the pathogens. sahKO mutants showed increased SA and jasmonate levels compared to those of the wild type and OsSAH-overexpressing plants. Analysis of the OsSAH3 promoter indicated that its induction was mainly restricted around Magnaporthe oryzae infection sites. Taken together, our findings indicate that SA plays a vital role in immune signaling. Moreover, fine-tuning SA homeostasis through suppression of SA metabolism is an effective approach in studying broad-spectrum disease resistance in rice.


Asunto(s)
Resistencia a la Enfermedad/fisiología , Oryza/genética , Ácido Salicílico/metabolismo , China , Ciclopentanos , Dioxigenasas , Expresión Génica/genética , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/genética , Hidroxilación , Oryza/efectos de los fármacos , Oryza/metabolismo , Oxilipinas , Enfermedades de las Plantas/genética , Inmunidad de la Planta/efectos de los fármacos , Inmunidad de la Planta/fisiología , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente/metabolismo , Ácido Salicílico/farmacología
14.
Molecules ; 26(24)2021 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-34946657

RESUMEN

The rapid emergence of bacterial coinfection caused by cytosolic bacteria has become a huge threat to public health worldwide. Past efforts have been devoted to discover the broad-spectrum antibiotics, while the emergence of antibiotic resistance encourages the development of antibacterial agents. In essence, bacterial virulence is a factor in antibiotic tolerance. However, the discovery and development of new antibacterial drugs and special antitoxin drugs is much more difficult in the antibiotic resistance era. Herein, we hypothesize that antitoxin hemolytic activity can serve as a screening principle to select antibacterial drugs to combat coinfection from natural products. Being the most abundant natural drug of plant origins, flavonoids were selected to assess the ability of antibacterial coinfections in this paper. Firstly, we note that four flavonoids, namely, baicalin, catechin, kaempferol, and quercetin, have previously exhibited antibacterial abilities. Then, we found that baicalin, kaempferol, and quercetin have better inhibitions of hemolytic activity of Hla than catechin. In addition, kaempferol and quercetin, have therapeutic effectivity for the coinfections of Staphylococcus aureus and Pseudomonas aeruginosa in vitro and in vivo. Finally, our results indicated that kaempferol and quercetin therapied the bacterial coinfection by inhibiting S. aureus α-hemolysin (Hla) and reduced the host inflammatory response. These results suggest that antitoxins may play a promising role as a potential target for screening flavonoids to combat bacterial coinfection.


Asunto(s)
Antibacterianos , Proteínas Bacterianas , Flavonoides , Proteínas Hemolisinas , Pseudomonas aeruginosa/metabolismo , Staphylococcus aureus/metabolismo , Antibacterianos/química , Antibacterianos/farmacología , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/metabolismo , Evaluación Preclínica de Medicamentos , Flavonoides/química , Flavonoides/farmacología , Proteínas Hemolisinas/antagonistas & inhibidores , Proteínas Hemolisinas/metabolismo
15.
Angew Chem Int Ed Engl ; 60(28): 15340-15343, 2021 07 05.
Artículo en Inglés | MEDLINE | ID: mdl-33899272

RESUMEN

G-quadruplexes (G4s) are prevalent in oncogenes and are potential antitumor drug targets. However, binding selectivity of compounds to G4s still faces challenges. Herein, we report a platinum(II) complex (Pt1), whose affinity to G4-DNA is activated by adaptive binding and selectivity controlled by binding kinetics. The resolved structure of Pt1/VEGF-G4 (a promoter G4) shows that Pt1 matches 3'-G-tetrad of VEGF-G4 through Cl- -dissociation and loop rearrangement of VEGF-G4. Binding rate constants are determined by coordination bond breakage/formation, correlating fully with affinities. The selective rate-determining binding step, Cl- -dissociation upon G4-binding, is 2-3 orders of magnitude higher than dsDNA. Pt1 potently targets G4 in living cells, effectively represses VEGF expression, and inhibits vascular growth in zebrafish. We show adaptive G4-binding activation and controlled by kinetics, providing a complementary design principle for compounds targeting G4 or similar biomolecules.


Asunto(s)
Antineoplásicos/farmacología , G-Cuádruplex/efectos de los fármacos , Compuestos Organoplatinos/farmacología , Antineoplásicos/química , Sitios de Unión/efectos de los fármacos , Células HeLa , Humanos , Cinética , Estructura Molecular , Compuestos Organoplatinos/química
16.
IEEE J Biomed Health Inform ; 25(9): 3278-3287, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33373308

RESUMEN

Combing brain-computer interfaces (BCI) and virtual reality (VR) is a novel technique in the field of medical rehabilitation and game entertainment. However, the limitations of BCI such as a limited number of action commands and low accuracy hinder the widespread use of BCI-VR. Recent studies have used hybrid BCIs that combine multiple BCI paradigms and/or the multi-modal biosensors to alleviate these issues, which may become the mainstream of BCIs in the future. The main purpose of this review is to discuss the current status of multi-modal BCI-VR. This study first reviewed the development of the BCI-VR, and explored the advantages and disadvantages of incorporating eye tracking, motor capture, and myoelectric sensing into the BCI-VR system. Then, this study discussed the development trend of the multi-modal BCI-VR, hoping to provide a pathway for further research in this field.


Asunto(s)
Interfaces Cerebro-Computador , Realidad Virtual , Electroencefalografía , Humanos , Interfaz Usuario-Computador
17.
Zhonghua Nan Ke Xue ; 26(8): 717-721, 2020 Aug.
Artículo en Chino | MEDLINE | ID: mdl-33377733

RESUMEN

OBJECTIVE: To investigate the factors influencing the recovery from childhood inguinal herniorrhaphy (IH)-induced vas deferens obstruction following microscopic vasovasostomy. METHODS: We retrospectively analyzed the clinical data on 41 cases of microscopic vasovasostomy for obstructive azoospermia in our hospital from July 2015 to September 2018. All the patients had a history of inguinal hernia treated by IH in the childhood. We performed scrotal ultrasonography, semen analysis and seminal plasma biochemistry to confirm vas deferens obstruction preoperatively. If sperm was observed for ≥2 times in semen examination after vasovasostomy, we considered the vas deferens successfully unobstructed. RESULTS: Microscopic vasovasostomy was successfully completed in 39 of the cases, of which2 were lost to follow-up, with a follow-up rate of 94.8% (37/39). The patients, at the mean age of (25.54 ± 2.85) years and with body mass index (BMI) of (24.92 ± 2.79) kg/m2 and post-IH time of (18.97 ± 2.58) years, were followed up for (13.05 ± 3.74) months. Successful recovery from vas deferens obstruction was observed in 78.4% (29/37) of the patients after IH, 80.0% (16/20) in the < 26-year-olds, 76.5% (13/17) in the ≥26-year-olds (P = 0.795), 75.0% (12/16) in those with BMI < 24.92 kg/m2 , 81.0% (17/21) in those with BMI ≥24.92 kg/m2 (P = 0.807), 78.6% (11/14) in those with post-IH time of < 19 years, 18.3% (18/23) in those with post-IH time of ≥19 years (P = 0.982), 60.0% (12/20) in those with sperm and 82.4% (14/17) in those without sperm found intraoperatively (P = 0.428), 42.9% (3/7) in those treated by unilateral and 82.4% (26/30) in those by bilateral vasovasostomy (P = 0.027). Multivariate logistic regression analysis showed a close correlation between the operation side and postoperative recovery from vas deferens obstruction (P = 0.022). CONCLUSIONS: For male patients undergoing microscopic vasovasostomy for childhood IH-induced vas deferens obstruction, the operation side is an independent factor influencing postoperative recovery, while age, BMI, post-IH time, and intraoperative presence or absence of sperm are not significantly correlated with it.


Asunto(s)
Enfermedades de los Genitales Masculinos/cirugía , Hernia Inguinal/complicaciones , Conducto Deferente/cirugía , Vasovasostomía , Adulto , Niño , Enfermedades de los Genitales Masculinos/etiología , Herniorrafia , Humanos , Masculino , Estudios Retrospectivos , Conducto Deferente/fisiopatología , Adulto Joven
18.
J Org Chem ; 85(16): 10719-10727, 2020 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-32664733

RESUMEN

A range of indolizine smoothly underwent visible-light-induced intermolecular [3+2] annulations with internal alkynes to afford pyrrolo[2,1,5-cd]indolizine in good to excellent yields with high regioselectivity. Through this cascade reaction, a series of fluoroactive fused indolizines with a large π-system were conveniently synthesized. The usage of visible light as energy source with air as a stoichiometric oxidant under simple conditions makes this process attractive and practical.

19.
IUCrdata ; 5(Pt 11): x201433, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36340012

RESUMEN

The asymmetric unit of the title compound, [PtCl2(C15H20N2S)], comprises one PtII ion, one N-heterocyclic carbene(NHC)-thio-ether ligand and two chloride ions. The PtII ion is four-coordinated by one C atom and one S atom of the NHC-thio-ether ligand, and by two chloride ions, forming an approximately square-planar geometry. In the crystal, the mol-ecules are linked via C-H⋯Cl and C-H⋯π inter-actions, forming a layer parallel to the ab plane.

20.
Nanotechnology ; 29(8): 085604, 2018 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-29300178

RESUMEN

FeCo-C core-shell nanoparticles (NPs) with diameters of 10-50 nm have been fabricated on a large scale by one-step metal-organic chemical vapor deposition using the mixture of cobalt acetylacetonate and iron acetylacetonate as the precursor. The Fe/Co molar ratio of the alloy nanocores and graphitization degree of C shells, and thus the magnetic and electric properties of the core-shell NPs, can be tuned by the deposition temperature ranging from 700 °C to 900 °C. Comparative tests reveal that a relatively high Fe/Co molar ratio and low graphitization degree benefit the microwave absorption (MA) performance of the core-shell NPs. The composite with 20 wt% core-shell NP obtained at 800 °C and 80 wt% paraffin exhibits an optimal reflection loss [Formula: see text] of -60.4 dB at 7.5 GHz with a thickness of 3.3 mm, and an effective absorption bandwidth (frequency range for RL ≤10 dB) of 9.2 GHz (8.8-18.0 GHz) under an absorber thickness of 2.5 mm. Our study provides a facile route for the fabrication of alloy-C core-shell nanostructures with high MA performance.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...