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












Base de dados
Intervalo de ano de publicação
1.
Food Funct ; 2024 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-39385719

RESUMO

Correction for 'A comparative study of the hypolipidemic effects and mechanisms of action of Laminaria japonica- and Ascophyllum nodosum-derived fucoidans in apolipoprotein E-deficient mice' by Tian Liu et al., Food Funct., 2024, 15, 5955-5971, https://doi.org/10.1039/D3FO05521C.

2.
Angew Chem Int Ed Engl ; : e202415092, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39290153

RESUMO

Chiral supramolecular aggregates have the potential to explore circularly polarized lasing with large dissymmetry factors. However, the controllable assembly of chiral superstructures towards deterministic circularly polarized laser emission remains elusive. Here, we design a pair of chiral organic molecules capable of stacking into a pair of definite helical superstructures in microcrystals, which enables circularly polarized lasing with deterministic chirality and high dissymmetry factors. The microcrystals function as optical cavities and gain media simultaneously for laser oscillations, while the supramolecular helices endow the laser emission with strong and opposite chirality. As a result, the microcrystals of two enantiomers allow for circularly polarized laser emission with opposite chirality and high dissymmetry factors up to ~1.0. This work demonstrates the chiral supramolecular assemblies as an excellent platform for high-performance circularly polarized lasers.

3.
J Am Chem Soc ; 146(32): 22583-22589, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39102645

RESUMO

Circularly polarized (CP) lasers hold tremendous potential for advancing spin information communication and display technologies. Organic materials are emerging candidates for high-performance CP lasers because of their abundant chiral structures and excellent gain characteristics. However, their dissymmetry factor (glum) in CP emission is typically low due to the weak chiral light matter interactions. Here, we presented an effective approach to significantly amplifying glum by leveraging the intrinsic 2D-chiroptical response of an anisotropic organic supramolecular crystal. The organic complex microcrystal was designed to exhibit large 2D-chiroptical activities through strong coupling interactions between their remarkable linear birefringence (LB) and high degree of fluorescence linear polarization. Such 2D-chiroptical response can be further enhanced by the stimulated emission resulted from an increased degree of linear polarization, yielding a nearly pure CP laser with an exceptionally high glum of up to 1.78. Moreover, exploiting the extreme susceptibility of LB to temperature, we demonstrate a prototype of temperature-controlled chiroptical switches. These findings offer valuable insights for harnessing organic crystals to facilitate the development of high-performance CP lasers and other chiroptical devices.

4.
Food Funct ; 15(11): 5955-5971, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38738998

RESUMO

The structural characteristics of fucoidans exhibit species and regional diversity. Previous studies have demonstrated that Laminaria japonica- and Ascophyllum nodosum-derived fucoidans have type I and type II fucosyl chains, respectively. These chemical differences may contribute to distinct hypolipidemic effects and mechanisms of action. Chemical analysis demonstrated that the percentage contents of sulfate, glucuronic acid, and galactose were higher in L. japonica-derived fucoidans than those of A. nodosum-derived fucoidans. In hyperlipidemic apolipoprotein E-deficient mice, both A. nodosum- and L. japonica-derived fucoidans significantly decreased the plasma and hepatic levels of total cholesterol and triglyceride, leading to the reduction of atherosclerotic plaques. Western blotting experiments demonstrated that these fucoidans significantly enhanced the expression and levels of scavenger receptor B type 1, cholesterol 7 alpha-hydroxylase A1, and peroxisome proliferator-activated receptor (PPAR)-α, contributing to circulating lipoprotein clearance and fatty acid degradation, respectively. Differentially, L. japonica-derived fucoidan significantly increased the LXR/ATP-binding cassette G8 signaling pathway in the small intestine, as revealed by real-time quantitative PCR, which may lead to further cholesterol and other lipid excretion. Collectively, these data are useful for understanding the hypolipidemic mechanisms of action of seaweed-derived fucoidans, and their potential application for the prevention and/or treatment of atherosclerotic cardiovascular diseases.


Assuntos
Apolipoproteínas E , Ascophyllum , Hipolipemiantes , Laminaria , Polissacarídeos , Animais , Laminaria/química , Ascophyllum/química , Camundongos , Polissacarídeos/farmacologia , Polissacarídeos/química , Hipolipemiantes/farmacologia , Apolipoproteínas E/genética , Masculino , Camundongos Endogâmicos C57BL , Triglicerídeos/sangue , Triglicerídeos/metabolismo , Colesterol/sangue , Colesterol/metabolismo , Camundongos Knockout , PPAR alfa/metabolismo , PPAR alfa/genética , Hiperlipidemias/tratamento farmacológico , Hiperlipidemias/metabolismo , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Fígado/metabolismo , Fígado/efeitos dos fármacos , Humanos , Algas Comestíveis
5.
Ann Hematol ; 103(8): 2993-3004, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38662205

RESUMO

The prognosis of patients diagnosed with relapsed or refractory (R/R) T-lymphoblastic leukemia/lymphoma (T-ALL/LBL) has consistently been unsatisfactory, with limited treatment options. As reports, the CAG regimen can serve as a salvage treatment for R/R T-ALL/LBL, but there remains a subset of patients who do not benefit from it. Recent studies have indicated that daratumumab (Dara) and venetoclax (Ven) may offer promising therapeutic benefits for T-ALL/LBL. In light of these findings, we conducted a safety and efficacy evaluation of the enhanced treatment regimen, combining Dara and Ven with aclarubicin, cytarabine, granulocyte colony-stimulating factor, and etoposide (CAGE), in patients suffering from R/R T-ALL/LBL. The participants in this phase I trial were patients with R/R T-ALL/LBL who fail to standard treatment regimens. During each 28-day cycle, the patients were treated by Dara, Ven, cytarabine, aclarubicin, granulocyte colony-stimulating factor, etoposide. The primary endpoint of this study was the rate of remission. This report presents the prospective outcomes of 21 patients who received the salvage therapy of Dara and Ven combined with the CAGE regimen (Dara + Ven + CAGE). The objective remission rate (ORR) was determined to be 57.1%, while the complete remission (CR) rate was 47.6%. Notably, patients with the early T-cell precursor (ETP) subtype exhibited a significantly higher remission rate in the bone marrow compared to non-ETP patients (100% vs. 44.4%, p = 0.044). The Dara + Ven + CAGE regimen demonstrated a favorable remission rate in patients with R/R T-ALL/LBL. Moreover, the treatment was well-tolerated.


Assuntos
Anticorpos Monoclonais , Protocolos de Quimioterapia Combinada Antineoplásica , Compostos Bicíclicos Heterocíclicos com Pontes , Citarabina , Etoposídeo , Sulfonamidas , Humanos , Sulfonamidas/administração & dosagem , Sulfonamidas/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Etoposídeo/administração & dosagem , Etoposídeo/efeitos adversos , Etoposídeo/uso terapêutico , Citarabina/administração & dosagem , Citarabina/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/efeitos adversos , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Aclarubicina/administração & dosagem , Aclarubicina/uso terapêutico , Adulto Jovem , Terapia de Salvação , Idoso , Adolescente
6.
Adv Mater ; 35(52): e2305260, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37754067

RESUMO

Spin-polarized lasers, arising from stimulated emission of imbalanced spin populations, play a vital role in spin-optoelectronics. It is usually tackled by external spin injection, inevitably suffering from additional losses across the barriers from injection sources to gain materials. Herein, spin-polarized coherent light emission is self-triggered from the 1D-anchoring-3D perovskites, where the imbalanced populations in achiral 3D perovskites are endowed with the spin selectivity of exciton chirality (EC) underpinned by chiral 1D perovskites. Efficient transfer of EC is enabled by rapid energy transfer, thereby creating an imbalance of the spin population of excited states. Stimulated emission of such populations brings self-triggered spin-polarized amplified spontaneous emission in the composite perovskites, yielding a higher degree of polarization (DOP) than that based on optical spin injection into bare achiral 3D perovskites. Chemical diversity of composite perovskites not only enables to adjust band gap for broadband output of spin-polarized light signals but also promises to manipulate radiative decay and spin relaxation toward remarkably increased DOP. These results highlight the importance of EC transfer mechanism for spin-polarized lasing and represent a crucial step toward the development of chiral-spintronics.

8.
J Oncol ; 2022: 2900310, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36483984

RESUMO

Objective: The objective is to explore the effectiveness and safety of CAR T-cell therapy in advanced relapsed/refractory central nervous system B-cell lymphoma and compare the impact of autologous stem cell transplantation (ASCT) plus CAR T-cell therapy versus sequential CART therapy on the survival of patients. Methods: The retrospective analysis was based on the data of 17 patients with advanced relapsed/refractory central nervous system B-cell lymphoma. Bridging chemotherapy was applied before CAR T-cell infusion to further reduce the tumor burden. For patients with autologous hematopoietic stem cell successful collection, CD19/20/22CAR T-cell immunotherapy following ASCT was performed with the thiotepa-containing conditioning regimen, while sequential CD19/CD20/CD22CAR T-cell therapy was applied. For lymphodepletion, patients received bendamustine or fludarabine monotherapy or fludarabine combined with cyclophosphamide pre-CART-cell infusion. Results: Out of the 17 patients, 8 completed ASCT plus CART cell therapy, while 9 patients completed CART cell alone therapy. In efficacy assessment at 3 months after infusion, the objective response rate (ORR) was 12/17 (71%) and the complete response rate (CRR) was 11/17 (65%). The CRR of the ASCT group and non-ASCT was 100% and 44.4%, respectively (P < 0.01). The median progression-free survival was 16.3 (2.6-24.5) months, and the median overall survival was 19.3 (6-24.5) months. Patients who underwent ASCT plus CART cell therapy had significantly longer PFS (P < 0.01) and OS (P < 0.01). Grade 3 or higher immune effector cell-associated neurologic toxicity syndrome (≥grade 3 ICANS) and cytokine release syndrome (≥grade 3 CRS) events occurred in 29% and 41% of the patients, respectively. No treatment-related death occurred. Conclusion: The CAR T-cell therapy could augment its efficacy in the treatment of advanced relapsed/refractory CNS B-cell lymphoma, while ASCT in combination with CART can induce durable responses and OS with a manageable side effect.

9.
Eur J Radiol ; 157: 110567, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36283194

RESUMO

OBJECTIVES: Flow cytometry (FC) is a critical diagnostic approach for guiding targeted chemotherapy and cellular immunotherapy for relapsed and refractory lymphoma patients. The aim of the study was to investigate the value of ultrasound-guided fine needle aspiration (FNA) to improve the quality of FC specimens in relapsed and refractory diffuse large B-cell lymphoma (R/R DLBCL). METHODS: Twenty patients with R/R DLBCL after standard treatment were included. The primary lesions of all cases were confirmed by pathology. FNA and core needle biopsy (CNB) were both used for ultrasound-guided puncture, the specimens obtained by FNA are directly examined by FC, and the specimens by CNB were subjected to FC after grinding. The accuracy of FC with the two methods were evaluated using histopathology as the gold standard. RESULTS: Of the 20 R/R DLBCL cases, 19 were diagnosed as DLBCL pathologically and one was diagnosed as inflammatory granuloma. Among the specimens obtained by CNB, 14 cases examined by FC after grinding showed abnormal mature B cells, five cases were missed, all cases are not misdiagnosed. Among the specimens obtained by FNA, 18 cases showed FC-confirmed abnormal mature B cells, one case was missed, all cases are not misdiagnosed. The sensitivity, specificity, and accuracy of FC with CNB and FNA were 73.68 % (14/19) vs 94.73 % (18/19), 100 % (1/1) vs 100 % (1/1), and 75 % (15/20) vs 97.14 % (19/20), respectively. The sensitivity of the two puncture methods of FC of DLBCL was statistically different (p < 0.001). CONCLUSION: Sampling with ultrasound-guided FNA is of great value to improve the quality of FC specimens. FNA can significantly improve the sensitivity and accuracy of FC diagnosis in R/R DLBCL.


Assuntos
Linfoma Difuso de Grandes Células B , Linfoma não Hodgkin , Humanos , Biópsia por Agulha Fina/métodos , Sensibilidade e Especificidade , Biópsia Guiada por Imagem , Biópsia com Agulha de Grande Calibre/métodos , Ultrassonografia de Intervenção , Linfoma Difuso de Grandes Células B/diagnóstico por imagem , Estudos Retrospectivos
10.
J Environ Sci (China) ; 64: 190-196, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29478639

RESUMO

A co-current flow rotating packed bed was applied to remove volatile organic compounds (VOCs) by sodium hypochlorite (NaClO) and surfactant (sodium dodecyl benzene sulfonate, SDBS) from air stream. Xylene was used as a model VOC herein. The effect of pH, concentration of NaClO and SDBS solution, liquid flow rate, gas flow rate and rotational speed on xylene removal efficiency and overall mass transfer coefficient (KGa) were discussed. Then, a correlation for KGa of the co-current rotating packed bed was proposed by fitting the experimental data of KGa and independent variables of liquid/gas ratio, rotational speed, pH, NaClO concentration and treatment time, which was in good agreement with the experimental data (the deviation≤±30%).


Assuntos
Filtros de Ar , Poluentes Atmosféricos/química , Hipoclorito de Sódio/química , Tensoativos/química , Compostos Orgânicos Voláteis/química
11.
Carbohydr Polym ; 175: 557-564, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28917901

RESUMO

Bone disease is a public health problem around the word, and it is urgent to develop novel tissue engineering scaffolds for the complicated cranial bone regeneration. The present work developed a novel triple crosslinked polysaccharides based injectable hydrogel to composite bio-glass (BG) for cranial bone repair. Dynamic mechanical analysis showed the storage modulus (G') of the hydrogel reached to ∼4000Pa. While after compositing BG, G' exceeded 4500Pa. The degradation behavior of the hydrogel is influenced by hydrogel composition, crosslinking methods and degradation environment. Through compositing BG for rat cranial bone repair, excellent bone regeneration effect was achieved (chunks of "white" new tissue was detected in the defected site, HE histopathological analysis confirmed the new tissue was bone tissue). Thus, the hydrogel is suitable as the carrier of BG for bone repair, demonstrating the prepared triple crosslinked hydrogel is potential for bone tissue engineering applications.


Assuntos
Regeneração Óssea , Cerâmica , Hidrogéis/química , Polissacarídeos/química , Engenharia Tecidual , Alicerces Teciduais , Animais , Ratos
12.
J Mater Chem B ; 5(20): 3739-3748, 2017 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32264062

RESUMO

Current hydrogels based on chondroitin sulfate (ChS) generally lack the necessary strength and precise mechanical tunability. Addressing these limitations, covalent cross-linking has evolved to produce hydrogels with desirable properties. However, such a methodology always precludes injection and self-healing. In this study, we employ DA click chemistry and dynamic acylhydrazone bond cross-linking for hydrogel formation that overcomes the limitations of current ChS hydrogels. Dynamic acylhydrazone bonds afford the hydrogel injectability and self-healing ability, while DA click chemistry facilitates the employment of covalent crosslinking for stabilization in vivo and modulating hydrogel properties in vivo. The study reveals that the obtained hydrogel possesses highly tunable viscoelastic and rheological properties, swelling and degradation behavior, and injectability and self-healing ability compared with ChS hydrogels cross-linked by single DA click chemistry or acylhydrazone bonds. Meanwhile, this hydrogel shows increased viability and reduced apoptosis of rat mesenchymal stem cells, and excellent tissue adhesive ability in vivo. The hydrogel was loaded with BMP-4 and used as a scaffold for rat cranial bone tissue engineering. The results demonstrated that new bone tissue was detected in the defected area of the cranial bone. Thus, this cytocompatible, injectable and self-healing hydrogel with tunable properties can be used as a scaffold for cranial bone tissue engineering and promote bone formation.

13.
Sci Rep ; 5: 9810, 2015 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-25961417

RESUMO

Many-body problem on the honeycomb lattice systems have been the subject of considerable experimental and theoretical interest. Here we investigate the phase transitions of the ionic Hubbard model on the honeycomb lattice with an alternate ionic potential for the half filling and hole doping cases by means of cellular dynamical mean field theory combining with continue time quantum Monte Carlo as an impurity solver. At half filling, as the increase of the interaction at a fixed ionic potential, we find the single particle gap decreases firstly, reaches a minimum at a critical interaction Uc, then increases upturn. At Uc, there is a band insulator to Mott insulator transition accompanying with the presence of the antiferromagnetic order. Away from half filing, the system shows three phases for the different values of hole density and interaction, paramagnetic metal, antiferromagnetic metal and ferromagnetic metal. Further, we present the staggered particle number, the double occupancy, the staggered magnetization, the uniform magnetization and the single particle spectral properties, which exhibit characteristic features for those phases.

14.
Sci Rep ; 4: 6918, 2014 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-25370072

RESUMO

Quantum magnetic phase transition in square-octagon lattice was investigated by cellular dynamical mean field theory combining with continuous time quantum Monte Carlo algorithm. Based on the systematic calculation on the density of states, the double occupancy and the Fermi surface evolution of square-octagon lattice, we presented the phase diagrams of this splendid many particle system. The competition between the temperature and the on-site repulsive interaction in the isotropic square-octagon lattice has shown that both antiferromagnetic and paramagnetic order can be found not only in the metal phase, but also in the insulating phase. Antiferromagnetic metal phase disappeared in the phase diagram that consists of the anisotropic parameter λ and the on-site repulsive interaction U while the other phases still can be detected at T = 0.17. The results found in this work may contribute to understand well the properties of some consuming systems that have square-octagon structure, quasi square-octagon structure, such as ZnO.

15.
Sci Rep ; 4: 5367, 2014 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-24947369

RESUMO

Bilayer honeycomb lattice, with inter-layer tunneling energy, has a parabolic dispersion relation, and the inter-layer hopping can cause the charge imbalance between two sublattices. Here, we investigate the metal-insulator and magnetic phase transitions on the strongly correlated bilayer honeycomb lattice by cellular dynamical mean-field theory combined with continuous time quantum Monte Carlo method. The procedures of magnetic spontaneous symmetry breaking on dimer and non-dimer sites are different, causing a novel phase transition between normal anti-ferromagnet and layer anti-ferromagnet. The whole phase diagrams about the magnetism, temperature, interaction and inter-layer hopping are obtained. Finally, we propose an experimental protocol to observe these phenomena in future optical lattice experiments.

16.
Sci Rep ; 4: 4829, 2014 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-24777282

RESUMO

The Shastry-Sutherland lattice, one of the simplest systems with geometrical frustration, which has an exact eigenstate by putting singlets on diagonal bonds, can be realized in a group of layered compounds and raises both theoretical and experimental interest. Most of the previous studies on the Shastry-Sutherland lattice are focusing on the Heisenberg model. Here we opt for the Hubbard model to calculate phase diagrams over a wide range of interaction parameters, and show the competing effects of interaction, frustration and temperature. At low temperature, frustration is shown to favor a paramagnetic metallic ground state, while interaction drives the system to an antiferromagnetic insulator phase. Between these two phases, there are an antiferromagnetic metal phase and a paramagnetic insulator phase (which should consist of a small plaquette phase and a dimer phase) resulting from the competition of the frustration and the interaction. Our results may shed light on more exhaustive studies about quantum phase transitions in geometrically frustrated systems.

17.
Chemphyschem ; 12(15): 2763-70, 2011 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-21882333

RESUMO

We report on the preparation and characterization of CeO(2) nanofibers (CeO(2)-NFs) and nanocubes (CeO(2)-NCs), as well as Sm- and Gd-doped CeO(2) nanocubes (Sm-CeO(2)-NCs and Gd-CeO(2)-NCs), synthesized by a simple hydrothermal process for CO catalytic oxidation. The samples were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, and photoluminescence spectroscopy. Their oxygen-storing capacity (OSC) was examined by means of hydrogen temperature-programmed reduction (H(2)-TPR) and oxygen pulse techniques. Their catalytic properties for CO catalytic oxidation were comparatively investigated. The results showed that the CeO(2)-NFs possessed a higher catalytic activity compared to the CeO(2)-NCs because of their smaller size and the greater number of oxygen vacancies. The activity of the Sm-CeO(2)-NCs was higher than that of the CeO(2)-NCs due to an increase in the number of oxygen vacancies, which results from the substitution of Ce(4+) species with Sm(3+) ions. In contrast, Gd doping had a negative effect on the CO catalytic oxidation due to the special electron configuration of Gd(3+) (4f(7)). Our work demonstrates that the oxygen vacancies in pure CeO(2) and the electron configuration of the dopants in doped CeO(2) play an important role in CO oxidation.

18.
Huan Jing Ke Xue ; 32(12): 3657-61, 2011 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-22468535

RESUMO

Manganese oxide octahedral molecular sieves (OMS-2) for VOCs catalytic combustion were synthesized by refluxing method. The crystal structure, particle morphology, pore structure and H2-reduction ability were characterized by XRD, SEM, N2 adsorption-desorption and H2-TPR techniques. The catalytic activities of the OMS-2 calcined at different temperatures in benzene combustion and the stability of the sample calcined at 300 degrees C were evaluated. The results indicated that the effect of calcinations temperature on the surface characters of catalysts was remarkable. With higher calcination temperature, the samples showed lower surface area and pore volume, but larger average pore size. At the same time, high calcination temperature leaded to low activity. The benzene conversion of the sample calcined at 300 degrees C was 50% degrees C at 200 degrees C and 90% at 250 degrees C, respectively. The catalytic activity exhibited only 5% reduction after reaction at 260 degrees C for 70 h, which indicated that the as-made catalysts were very stable after calcination at 300 degrees C.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Poluição do Ar/prevenção & controle , Benzeno/isolamento & purificação , Compostos de Manganês/química , Óxidos/química , Compostos Orgânicos Voláteis/isolamento & purificação , Poluentes Atmosféricos/química , Benzeno/química , Catálise , Oxirredução , Compostos Orgânicos Voláteis/química
19.
J Nanosci Nanotechnol ; 9(2): 799-802, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19441395

RESUMO

Mesoporous carbon and mesoporous silica were prepared respectively with a same rosin-silica nanocomposite gel which was synthesized by cogelating tetra-ethyl-oxy-silane (silica source) and rosin (carbon source). Carbonizing the gel in nitrogen and then etching away silica with alkaline solution, mesoporous carbon with specific surface area larger than 800 m2/g was obtained. If calcining the gel at high temperature in air for given time, porous silica with surface area higher than 700 m2/g was done. BET measurement was employed to investigate the pore distribution and surface area of the samples. Most of the pores in both the porous carbon and porous silica were mesoscale, which makes the materials potential in enzyme supports for bio-catalyzed reaction or adsorbents for contaminants with large molecular size.

20.
Nanotechnology ; 20(8): 085611, 2009 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-19417459

RESUMO

A facile procedure for large-scale preparation of porous ZnO 1D nanomaterials with good electrical conductivity has been demonstrated for the first time. Porous ultrathin Ga-doped ZnO nanoneedles can be prepared by calcining the precursor of ultrathin Ga-doped basic zinc carbonate (BZC) nanoneedles obtained from BZC 3D superstructures, which are synthesized by a simple chemical co-precipitation method at room temperature, without using any catalyst, template or surfactant. There is evidence that the growth mechanisms of the BZC 3D superstructures and nanoneedles are correlated with the concentrations of ammonium ions and ethanol in the synthesis solution. The as-prepared porous Ga-doped ZnO nanoneedles have a thickness of only a couple of nanometers, consisting of many fine nanoparticles in a few nanometers. Electrical conductivity measurements indicate that porous ultrathin ZnO nanoneedles have a volume resistivity similar to that of the spherical Ga-doped ZnO nanoparticles. The porous nanostructures and good electrical conductivity make the porous ultrathin ZnO 1D nanoneedles promising candidates for applications in electrochemical fields.


Assuntos
Carbonatos/química , Cristalização/métodos , Gálio/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Compostos de Zinco/química , Óxido de Zinco/química , Condutividade Elétrica , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Porosidade , Propriedades de Superfície
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...