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1.
Wei Sheng Yan Jiu ; 53(4): 623-630, 2024 Jul.
Artículo en Zh | MEDLINE | ID: mdl-39155232

RESUMEN

OBJECTIVE: To understand the nutritional components of common cooked foods in Hubei Province. METHODS: Forty-nine common cooked foods consumed by residents in Hubei Province were collected, and their edible parts were homogenized and tested for various nutrient contents according to the national standard method. The nutrient-rich foods index(NRF)model was used to calculate the NRF index(NRF 9.3) of various cooked foods, and the nutritional value of common cooked foods in Hubei Province was evaluated. RESULTS: The result of the nutrient-rich food index model showed that the NRF 9.3 index of all cooked dishes ranged from-176.9 to 224.4, the NRF 9.3 index ranking of all types of cooked food was mainly related to cooking method. The NRF 9.3 index of cold mixed vegetable dishes was generally higher than the 75th percentile value(66.9) of the monitoring result, indicating higher nutritional value. The mean NRF 9.3 index of fish and shrimp cooked foods(72.4)monitored in this study was higher than that of meat cooked foods(21.5). The sodium content of pickled vegetables and some pre-packaged cooked foods was relatively high, RESULTS: ing in negative NRF 9.3 index and lower nutritional value. The NRF 9.3 index of Xiangyang beef noodles(33.1)and tofu noodles(37.1)was higher than that of beef offal noodles(5.1). CONCLUSION: Vegetables and fish and shrimp are better sources of nutrition, and "cold and dressed with sauce" are a better way to cook. Pickled vegetables contain too many restricted nutrients, and their consumption frequency and amount should be reduced.


Asunto(s)
Culinaria , Análisis de los Alimentos , Valor Nutritivo , Verduras , Culinaria/métodos , China , Análisis de los Alimentos/métodos , Verduras/química , Nutrientes/análisis , Humanos , Animales , Carne/análisis
2.
Int J Neurosci ; 130(2): 186-192, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31696761

RESUMEN

Background and Purpose: Oxidative stress is involved in the development of infections. However, whether oxidative stress indicators can be used as markers of stroke-associated infection (SAI) is still unclear. The purpose of this study was to test the predictive values of superoxide dismutase (SOD) and malondialdehyde (MDA) levels for SAI incidence.Methods: A total of 45 consecutive patients with ischemic stroke who were admitted to our hospital were enrolled. A prospective study was carried out to observe the occurrence of SAI during the first 7 days after stroke. Accordingly, the patients were divided into SAI and non-SAI groups. The relationship between SOD and MDA serum levels and SAI was analyzed.Results: The patients in the SAI group had significantly higher serum SOD levels than those in the non-SAI group (41.638 ± 3.428 U/ml vs. 36.542 ± 9.114 U/ml, p = 0.033). However, there were no significant differences in MDA levels between the SAI and non-SAI group (p > 0.05). The discriminating ability of serum SOD level for SAI was measured using an ROC curve. Serum level of SOD >38.16 U/ml was useful in diagnosing SAI with a sensitivity of 88% and a specificity of 61%. Kaplan-Meier curves showed that the group with serum SOD level >38.16 U/ml had higher rates of SAI incidence (χ2 = 9.688, p = 0.002; log rank test). Furthermore, Cox regression analysis indicated that a serum SOD level >38.16 U/ml was an independent risk factor for SAI (hazard ratio = 5.836; 95% CI, 1.298-26.244; p = 0.021).Conclusions: Acute-phase serum SOD level could be a predictor of SAI.


Asunto(s)
Isquemia Encefálica/sangre , Infecciones/sangre , Infecciones/diagnóstico , Inflamación/sangre , Estrés Oxidativo , Accidente Cerebrovascular/sangre , Superóxido Dismutasa/sangre , Anciano , Biomarcadores/sangre , Isquemia Encefálica/complicaciones , Femenino , Humanos , Infecciones/etiología , Inflamación/etiología , Masculino , Malondialdehído/sangre , Persona de Mediana Edad , Estrés Oxidativo/fisiología , Estudios Prospectivos , Sensibilidad y Especificidad , Accidente Cerebrovascular/complicaciones
3.
Neuroimmunomodulation ; 26(5): 234-238, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31661704

RESUMEN

OBJECTIVE: To explore the diversity and clinical features of anti-glutamate decarboxylase (GAD) antibody-associated neurological diseases. METHODS: Clinical data of a series of 5 patients positive for anti-GAD antibodies were retrospectively analyzed. RESULTS: All 5 patients were female, with a median age of 41.5 years (range 19-60 years). Their neurological symptoms included stiff-person syndrome (SPS), encephalitis, myelitis, cramp, visual loss, and paresthesia. Three patients (60%) were diagnosed with tumors, 2 cases of thymic tumor and 1 of breast cancer. On immunohistochemistry for tumor pathology, expression of GAD65 was found only in 1 patient. Four patients (80%) had abnormal brain MRI findings. All patients received immunotherapy and improved significantly after treatment, but 4 (80%) then experienced a relapse. CONCLUSIONS: Neurological manifestations in anti-GAD-positive patients are diverse and include SPS, encephalitis, myelitis, cramp, visual loss, and paresthesia.


Asunto(s)
Autoanticuerpos/inmunología , Enfermedades Autoinmunes del Sistema Nervioso/fisiopatología , Glutamato Descarboxilasa/inmunología , Síndromes Paraneoplásicos del Sistema Nervioso/fisiopatología , Adulto , Enfermedades Autoinmunes del Sistema Nervioso/diagnóstico por imagen , Enfermedades Autoinmunes del Sistema Nervioso/inmunología , Encéfalo/diagnóstico por imagen , Neoplasias de la Mama/metabolismo , Encefalitis/diagnóstico por imagen , Encefalitis/inmunología , Encefalitis/fisiopatología , Femenino , Glutamato Descarboxilasa/metabolismo , Humanos , Imagen por Resonancia Magnética , Persona de Mediana Edad , Calambre Muscular/inmunología , Calambre Muscular/fisiopatología , Mielitis/inmunología , Mielitis/fisiopatología , Síndromes Paraneoplásicos del Sistema Nervioso/diagnóstico por imagen , Síndromes Paraneoplásicos del Sistema Nervioso/inmunología , Parestesia/inmunología , Parestesia/fisiopatología , Recurrencia , Estudios Retrospectivos , Síndrome de la Persona Rígida/inmunología , Síndrome de la Persona Rígida/fisiopatología , Neoplasias del Timo/metabolismo , Trastornos de la Visión/inmunología , Trastornos de la Visión/fisiopatología , Adulto Joven
4.
Yi Chuan ; 39(10): 888-896, 2017 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-29070484

RESUMEN

As it is well known, proper exercise benefits our mind and body, especially the skeletal muscle. Exercise increases the capacity of muscle metabolism, enhances the biological function of mitochondria, regulates the transformation of muscle fiber types and increases the muscle power. In recent years, more and more researches show that epigenetic regulation plays an important role in strengthening the muscle, and these studies mainly include DNA methylation, histone modification, and regulation of miRNA expression. In order to adapt to the body movement, these three epigenetic patterns change the metabolic capacity of skeletal muscle, mitochondrial biological function and muscle fiber types by regulating the gene expression of skeletal muscle. In this review, we summarize research progresses of exercise-induced epigenetic regulation of gene expression of skeletal muscle, in order to provide a reference for further studies of how sports improve our body health.


Asunto(s)
Epigénesis Genética , Ejercicio Físico , Regulación de la Expresión Génica , Músculo Esquelético/metabolismo , Metilación de ADN , Humanos
5.
ACS Appl Mater Interfaces ; 16(9): 11957-11972, 2024 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-38393750

RESUMEN

The usage of a conductive hydrogel in wearable sensors has been thoroughly researched recently. Nonetheless, hydrogel-based sensors cannot simultaneously have excellent mechanical property, high sensitivity, comfortable wearability, and rapid self-healing performance, which result in poor durability and reusability. Herein, a robust conductive hydrogel derived from one-pot polymerization and subsequent solvent replacement is developed as a wearable sensor. Owing to the reversible hydrogen bonds cross-linked between polymer chains and clay nanosheets, the resulting conductive hydrogel-based sensor exhibits outstanding flexibility, self-repairing, and fatigue resistance performances. The embedding of graphene oxide nanosheets offers an enhanced hydrogel network and easy release of wearable sensor from the target position through remote irradiation, while Li+ ions incorporated by solvent replacement endow the wearable sensor with low detection limit (sensing strain: 1%), high conductivity (4.3 S m-1) and sensitivity (gauge factor: 3.04), good freezing resistance, and water retention. Therefore, the fabricated wearable sensor is suitable to monitor small and large human motions on the site and remotely under subzero (-54 °C) or room temperature, indicating lots of promising applications in human-motion monitoring, information encryption and identification, and electronic skins.


Asunto(s)
Hidrogeles , Humanos , Arcilla , Conductividad Eléctrica , Enlace de Hidrógeno , Movimiento (Física) , Solventes
6.
J Neurol ; 271(8): 5046-5054, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38801431

RESUMEN

OBJECTIVE: The aim of our study was to analyze the characteristics of patients with autoimmune encephalitis (AE) to identify prognostic factors associated with the development of drug-resistant epilepsy (DRE). METHODS: In this retrospective observational cohort study, we enrolled adult patients with AE between January 2016 and December 2022. The patients were categorized into two groups based on the presence or absence of DRE at the last follow-up. The predictors of the development of DRE were investigated using logistic regression analysis. RESULTS: Among 121 AE patients, 75.2% (n = 91) experienced acute symptomatic seizures, and 29.8% (n = 36) developed DRE at the last follow-up. On multivariate regression analysis, the factors associated with DRE were antibody negativity (OR 3.628, 95% CI 1.092-12.050, p = 0.035), focal seizure (OR 6.431, 95% CI 1.838-22.508, p = 0.004), refractory status epilepticus (OR 8.802, 95% CI 2.445-31.689, p = 0.001), interictal epileptiform discharges on EEG (OR 6.773, 95% CI 2.206-20.790, p = 0.001), and T2/FLAIR hyperintensity in the limbic system (OR 3.286, 95% CI 1.060-10.183, p = 0.039). CONCLUSIONS: In this study, the risk of developing DRE was mainly observed among AE patients who were negative for antibodies or had focal seizures, refractory status epilepticus, interictal epileptiform discharges on EEG, and T2/FLAIR hyperintensity in the limbic system.


Asunto(s)
Epilepsia Refractaria , Encefalitis , Humanos , Masculino , Femenino , Epilepsia Refractaria/fisiopatología , Epilepsia Refractaria/etiología , Epilepsia Refractaria/diagnóstico , Estudios Retrospectivos , Adulto , Persona de Mediana Edad , Encefalitis/complicaciones , Encefalitis/diagnóstico , Pronóstico , Enfermedad de Hashimoto/complicaciones , Enfermedad de Hashimoto/fisiopatología , Anciano , Electroencefalografía , Estudios de Cohortes , Adulto Joven
7.
Seizure ; 120: 180-188, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39029408

RESUMEN

OBJECTIVE: To expand the clinical phenotype and mutation spectrum of familial mesial temporal lobe epilepsy (FMTLE) and provide a new perspective for exploring the pathological mechanisms of epilepsy caused by leucine-rich glioma inactivated 1 (LGI1) variants. METHODS: We reported clinical data from two families with FMTLE and screened patients for variants in the LGI1 gene using Whole-exome sequencing and Sanger sequencing. The clinical features of FMTLE were analysed. The pathogenicity of the causative loci was assessed according to the American College of Medical Genetics and Genomics guidelines, and potential pathogenic mechanisms were predicted through multiple bioinformatics and molecular dynamics software. RESULTS: We identified two novel LGI1 truncating variants within two large families with FMTLE: LGI1 (c.1174C>T, p.Q392X) and LGI1 (c.703C>T, p.Q235X). Compared to previous reports, we found that focal to bilateral tonic-clonic seizures are a common type of seizure in FMTLE. The clinical phenotypes of patients with FMTLE caused by LGI1 variants were relatively mild, and all patients responded well to valproic acid. Bioinformatics analyses and molecular dynamics simulations showed that protein structure and interactions were considerably weakened or damaged as a result of both variants. CONCLUSION: This study presents the first report identifying LGI1 as a potential novel pathogenic gene within FMTLE families, thereby broadening the mutation spectrum associated with FMTLE. The findings of this study offer novel insights and avenues for understanding the intricate molecular mechanisms underlying LGI1 variants and their correlations with patient phenotypes. This study proposes the possibility of familial focal epilepsy syndromes overlapping.


Asunto(s)
Epilepsia del Lóbulo Temporal , Péptidos y Proteínas de Señalización Intracelular , Linaje , Fenotipo , Adulto , Femenino , Humanos , Masculino , Adulto Joven , Epilepsia del Lóbulo Temporal/genética , Epilepsia del Lóbulo Temporal/fisiopatología , Epilepsia del Lóbulo Temporal/congénito , Péptidos y Proteínas de Señalización Intracelular/genética , Mutación , Niño , Adolescente
8.
J Nanosci Nanotechnol ; 13(1): 279-87, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23646727

RESUMEN

Organic dispersion agents can effectively decrease the surface roughness of films. Here, films containing organic dispersion agents are used to produce metal-insulator-metal structures. It was found that addition of Triton caused films to become denser, and thicker, and the leak current of devices to decrease by 10 times compared with that without Triton because of its uniform dispersion in the films. The resulting films were used as the insulator layer of thin film transistors containing a semiconductor layer of evaporated pentacene. The interface between the insulator and semiconductor layers was found to affect the arrangement of pentacene, and O2 plasma was used to improve the interface activity to increase the order of the pentacene molecules and enhance the carrier mobility of the devices.


Asunto(s)
Cristalización/métodos , Membranas Artificiales , Nanoestructuras/química , Nanoestructuras/ultraestructura , Dióxido de Silicio/química , Transistores Electrónicos , Transporte de Electrón , Diseño de Equipo , Análisis de Falla de Equipo , Ensayo de Materiales , Tamaño de la Partícula , Transición de Fase
9.
J Nanosci Nanotechnol ; 13(1): 365-9, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23646739

RESUMEN

We propose a multi-layer dye-sensitized solar cell (DSSC). Conventional DSSC components use a singular TiO2 particle size and a mono-layer active layer, but we demonstrate a multi-layer and multi-scale TiO2 particle based DSSC. Doping with large TiO2 particles can produce light scattering inside the DSSC component. Light scattering effects reduce TiO2 absorption at wavelengths of 200-300 nm. The unabsorbed light zig-zags between the Pt back electrode layer and the substrate, and enhances the Ru-dye absorption. To enhance the scattering, we doped the active layer with 20 wt% of large diameter TiO2. The multi-layer DSSC increases efficiency by about 15% compared with standard DSSCs.


Asunto(s)
Colorantes/química , Suministros de Energía Eléctrica , Nanoestructuras/química , Nanoestructuras/ultraestructura , Energía Solar , Titanio/química , Diseño de Equipo , Análisis de Falla de Equipo , Tamaño de la Partícula , Porosidad
10.
Ann Transl Med ; 11(7): 288, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-37090053

RESUMEN

Autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A) is an antibody-related astrocytic disease for which a specific GFAP antibody serves as a biological marker. Indeed, cerebral spinal fluid positive and/or seropositivity for GFAP is an important basis for its diagnosis. However, because patients with autoimmune encephalitis or demyelinating diseases can have a similar antibody profile, termed overlapping autoimmune syndrome, it remains a challenge for clinicians to diagnose and suitably classify autoimmune GFAP-A. To further understand the significance of GFAP antibody detection in neuroimmune diseases, this article discusses GFAP antibodies in autoimmune GFAP-A, progress for detection of GFAP antibodies, diagnostic significance of GFAP antibodies in prototypical disease, as well as overlapping syndrome.

11.
Micromachines (Basel) ; 14(5)2023 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-37241543

RESUMEN

The structure used in this study is as follows: substrate/PMMA/ZnS/Ag/MoO3/NPB/Alq3/LiF/Al. Here, PMMA serves as the surface flattening layer, ZnS/Ag/MoO3 as the anode, NPB as the hole injection layer, Alq3 as the emitting layer, LiF as the electron injection layer, and aluminum as the cathode. The properties of the devices with different substrates were investigated using P4 and glass, developed in the laboratory, as well as commercially available PET. After film formation, P4 creates holes on the surface. The light field distribution of the device was calculated at wavelengths of 480 nm, 550 nm, and 620 nm using optical simulation. It was found that this microstructure contributes to light extraction. The maximum brightness, external quantum efficiency, and current efficiency of the device at a P4 thickness of 2.6 µm were 72,500 cd/m2, 1.69%, and 5.68 cd/A, respectively. However, the maximum brightness of the same structure with PET (130 µm) was 9500 cd/m2. The microstructure of the P4 substrate was found to contribute to the excellent device performance through analysis of the AFM surface morphology, film resistance, and optical simulation results. The holes formed by the P4 substrate were created solely by spin-coating the material and then placing it on a heating plate to dry, without any special processing. To confirm the reproducibility of the naturally formed holes, devices were fabricated again with three different emitting layer thicknesses. The maximum brightness, external quantum efficiency, and current efficiency of the device at an Alq3 thickness of 55 nm were 93,400 cd/m2, 1.7%, and 5.6 cd/A, respectively.

12.
J Nanosci Nanotechnol ; 12(4): 3070-6, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22849067

RESUMEN

A novel approach has been developed to fabricate hills-like hierarchical structured TiO2 photoanodes for dye-sensitized solar cells (DSSCs). The appropriately aggregated TiO2 clusters in the photoanode layer could cause stronger light scattering and higher dye loading that increases the efficiency of photovoltaic device. For detailed light-harvesting study, different molecular weights of polyvinyl alcohol (PVA) were used as binders for TiO2 nanoparticles (P-25 Degussa) aggregation. A series of TiO2 films with dissimilar morphology, the reflection of TiO2 films, absorbance of attached dye, amount of dye loading, and performance of fabricated DSSC devices, were measured and investigated. An optimized device had energy conversion efficiency of 4.47% having a higher dye loading and good light harvesting, achieving a 23% increase of short-circuit current J(sc) in DSSCs.

13.
Membranes (Basel) ; 12(12)2022 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-36557145

RESUMEN

We use polyethylene glycol as an additive to explore how the hydrogen bonding of this additive changes the properties of SA8 blended sulfonated polyetheretherketone (SPEEK) composite films. We mixed a 5%wt polyethylene glycol solution into a 12.5%wt SA8 solution, and then prepared a film with a total weight of 40 g at a ratio of 1:99. The SA8 (PEG) solution was prepared and then mixed with 5%wt SPEEK solution, and a film-forming solution with a total weight of 8g in different mixing ratios was created. Polyethylene glycol (PEG) was mixed into the sulfonated polyarylether polymer SA8 to form physical cross-linking. Therefore, the sulfonated polyether ether ketone SPEEK was mixed in, and it exhibited good thermal stability and dimensional stability. However, there was some decrease in proton conductivity as the proportion of SPEEK increased. Although SPEEK mixed with sulfonated polymer reduces the proton conductivity, the physical cross-linking of PEG can improve the proton conductivity of the composite membrane, and adding SPEEK can not only solve the problem of the high sulfonation film swelling phenomenon, it can also improve the dimensional stability of the film through the hydrogen bonding force of PEG and obtain a composite film with excellent properties.

14.
Membranes (Basel) ; 12(10)2022 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-36295733

RESUMEN

This study fabricated a composite ePTFE-backed proton-exchange membrane by filling the pores on the ePTFE backing with sulfonated polyarylene ethers through an externally supplied electric field. The morphology changes were observed under an SEM. The results suggested that the application of an electric field had led to the effective filling of pores by polymers. In addition, the composite membrane featured good dimensional stability and swelling ratio, and its water uptake, proton conductivity and component efficiency increased with voltage. It is found in this study that the external application of an electric field resulted in the effective filling of pores in the ePTFE by sulfonated polyarylene ether polymers and, thus, an improved composite membrane performance.

15.
Membranes (Basel) ; 12(6)2022 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-35736289

RESUMEN

In this study, a series of high molecular weight ionomers of hexaarylbenzene- and fluorene-based poly(arylene ether)s were synthesized conveniently through condensation and post-sulfonation modification. The use a of blending method might increase the stacking density of chains and affect the formation both of interchain and intrachain proton transfer clusters. Multiscale phase separation caused by the dissolution and compatibility differences of blend ionomer in high-boiling-point solvents was examined through analysis and simulations. The blend membranes produced in this study exhibited a high proton conductivity of 206.4 mS cm−1 at 80 °C (increased from 182.6 mS cm−1 for precursor membranes), excellent thermal resistance (decomposition temperature > 200 °C), and suitable mechanical properties with a tensile strength of 73.8−77.4 MPa. As a proton exchange membrane for fuel cell applications, it exhibits an excellent power efficiency of approximately 1.3 W cm−2. Thus, the ionomer membranes have strong potential for use in proton exchange membrane fuel cells and other electrochemical applications.

16.
Membranes (Basel) ; 11(8)2021 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-34436389

RESUMEN

Series of partially fluorinated sulfonated poly(arylene ether)s were synthesized through nucleophilic substitution polycondensation from three types of diols and superhydrophobic tetra-trifluoromethyl-substituted difluoro monomers with postsulfonation to obtain densely sulfonated ionomers. The membranes had similar ion exchange capacities of 2.92 ± 0.20 mmol g-1 and favorable mechanical properties (Young's moduli of 1.60-1.83 GPa). The membranes exhibited considerable dimensional stability (43.1-122.3% change in area and 42.1-61.5% change in thickness at 80 °C) and oxidative stability (~55.5%). The proton conductivity of the membranes, higher (174.3-301.8 mS cm-1) than that of Nafion 211 (123.8 mS cm-1), was the percent conducting volume corresponding to the water uptake. The membranes were observed to comprise isolated to tailed ionic clusters of size 15-45 nm and 3-8 nm, respectively, in transmission electron microscopy images. A fuel cell containing one such material exhibited high single-cell performance-a maximum power density of 1.32 W cm2 and current density of >1600 mA cm-2 at 0.6 V. The results indicate that the material is a candidate for proton exchange membranes in fuel cell applications.

17.
Polymers (Basel) ; 13(21)2021 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-34771406

RESUMEN

Aromatic polyimine (PIM) was prepared through condensation polymerization between p-phenylene diamine and terephthalaldehyde via Schiff reactions. PIM can be physically crosslinked with ferrous ions into gel. The gel-composites, calcined at two consecutive stages, with temperatures ranging from 600 to 1000 °C, became Fe- and N-doped carbonaceous organic frameworks (FeNC), which demonstrated both graphene- and carbon nanotube-like morphologies and behaved as an electron-conducting medium. After the two-stage calcination, one at 1000 °C in N2 and the other at 900 °C in a mixture of N2 and NH3, an FeNC composite (FeNC-1000A900) was obtained, which demonstrated a significant O2 reduction peak in its current-voltage curve in the O2 atmosphere, and thus, qualified as a catalyst for the oxygen reduction reaction. It also produced a higher reduction current than that of commercial Pt/C in a linear scanning voltage test, and the calculated e-transferred number reached 3.85. The max. power density reached 400 mW·cm-2 for the single cell using FeNC-1000A900 as the cathode catalyst, which was superior to other FeNC catalysts that were calcined at lower temperatures. The FeNC demonstrated only 10% loss of the reduction current at 1600 rpm after 1000 redox cycles, as compared to be 25% loss for the commercial Pt/C catalyst in the durability test.

18.
Polymers (Basel) ; 13(14)2021 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-34301136

RESUMEN

Oleic acid (OA)-modified Fe3O4 nanoparticles were successfully covered with polyanilines (PANIs) via inverse suspension polymerization in accordance with SEM and TEM micrographs. The obtained nanoparticles were able to develop into a ferrite (α-Fe) and α″-Fe16N2 mixture with a superparamagnetic property and high saturated magnetization (SM) of 245 emu g-1 at 950 °C calcination under the protection of carbonization materials (calcined PANI) and other iron-compounds (α″-Fe16N2). The SM of the calcined iron-composites slightly decreases to 232 emu g-1 after staying in the open air for 3 months. The calcined mixture composite can be ground into homogeneous powders without the segregation of the iron and carbon phases in the mortar without significantly losing magnetic activities.

19.
Polymers (Basel) ; 12(3)2020 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-32182689

RESUMEN

Calcination reduction reaction is used to prepare Pt/EB (emeraldine base)-XC72 (Vulcan carbon black) composites as the cathode material of a proton exchange membrane fuel cell (PEMFC). The EB-XC72 core-shell composite obtained from directly polymerizing aniline on XC72 particles is able to chelate and capture the Pt-ions before calcination. X-ray diffraction spectra demonstrate Pt particles are successfully obtained on the EB-XC72 when the calcined temperature is higher than 600 °C. Micrographs of TEM and SEM illustrate the affluent, Pt nanoparticles are uniformly distributed on EB-XC72 at 800 °C (Pt/EB-XC72/800). More Pt is deposited on Pt/EB-XC72 composite as temperatures are higher than 600 °C. The Pt/EB-XC72/800 catalyst demonstrates typical type of a cyclic voltammograms (C-V) curve of a Pt-catalyst with clear Pt-H oxidation and Pt-O reduction peaks. The highest number of transferred electrons during ORR approaches 3.88 for Pt/EB-XC72/800. The maximum power density of the single cell based on Pt/EB-XC72/800 reaches 550 mW cm-2.

20.
Materials (Basel) ; 13(7)2020 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-32224884

RESUMEN

The small sized copper nanoparticles (Cu-NPs), prepared in the presence of triethylene tetramine (TETA) and assisted with microwave irradiation, have an extremely low melting temperature. Melting of the small sizezd Cu-NPs can be triggered by the heat generated from the e-beam irradiation during SEM and TEM image construction. The dispersed Cu atoms around the agglomerated big Cu particles can undergo recrystallization immediately due to the strong driving force of the huge temperature difference to normal melting temperature (Tm = 1085 °C). Some of the Cu-NPs with bigger sizes also recrystallize and agglomerate into dense, big particles. According to X-ray diffraction patterns, these particles can agglomerate into compact, ordered Cu crystals in less than five minutes at 60 °C. The melting and recrystallization related endothermic and exothermic phase transitions of Cu-NPs can be found from differential scanning calorimeter (DSC) thermograms and optical microscopic pictures.

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