Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
1.
Mater Horiz ; 11(2): 468-479, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-37965678

RESUMO

To cope with sophisticated application scenarios, carbon materials can provide opportunities for integrating multi-functionalities into superior electromagnetic interference (EMI) shielding properties. Nevertheless, carbon materials usually possess high electrical conductivity, which allows them to counteract electromagnetic waves by reflection. Moreover, the identification of factors that dominate the shielding mechanisms has typically been result-oriented, leading to a reliance on a trial-and-error approach for the development of shielding materials. Thus, it is crucial to identify the dominant factors for EMI shielding and elucidate the mechanism underlying the coordination of the balance between reflection and absorption in carbon materials. In this study, we developed a promising and viable approach to create Co@CNTs embedded in carbonized wood (CW) via chemical vapor deposition, producing Co@CNTs/CW foams. The CNTs, densely grown on the CW surface, tightly encapsulated the Co nanoparticles within them. By manipulating the Co content, the defect density and CNT length varied within the Co@CNTs. Through first-principles calculations, these variations substantially influenced the work function, charge density, and dipole moment of the Co@CNTs. Thus, defect-induced and interfacial polarizations were improved, inducing a transformation of the shielding mechanism from reflection to absorption. Regarding the Co@CNTs/CW foams, while high conductivity was essential for achieving satisfactory shielding performance, the enhanced polarization loss dominated the contribution of absorption to the overall shielding effectiveness. Taking advantage of the enhanced polarizations, the Co@CNTs/CW foams exhibited an impressive shielding effectiveness of 42.0 dB, along with an absorptivity of 0.64, which were instrumental in effectively minimizing secondary reflections. Remarkably, these as-prepared foams possessed outstanding hydrophobicity and Joule heating features with a water contact angle of 138° and a saturation temperature of 85.5 °C (2.5 V). Through the stimulation of voltage-driven Joule heating, the absorptivity of Co@CNTs/CW foams can be significantly enhanced to a range of 0.61 to 0.73, irrespective of the Co content. This research would provide a new avenue for designing carbon materials with an absorption-dominated mechanism integrated into EMI shielding performance.

2.
Front Oral Health ; 4: 1212728, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37377523

RESUMO

Objectives: Periodontitis disproportionately affects different racial and ethnic populations. We have previously reported the higher levels of Porphyromonas gingivalis and lower ratios of Streptococcus cristatus to P. gingivalis may contribute to periodontal health disparities. This prospective cohort study was designed to investigate if ethnic/racial groups responded differently to non-surgical periodontal treatment and if the treatment outcomes correlated to the bacterial distribution in patients with periodontitis before treatment. Methods: This prospective cohort pilot study was carried out in an academic setting, at the School of Dentistry, University of Texas Health Science Center at Houston. Dental plaque was collected from a total of 75 African Americans, Caucasians and Hispanics periodontitis patients in a 3-year period. Quantitation of P. gingivalis and S. cristatus was carried out using qPCR. Clinical parameters including probing depths and clinical attachment levels were determined before and after nonsurgical treatment. Data were analyzed using one-way ANOVA, the Kruskal-Wallis test, the paired samples t-test and the chi-square test. Results: The gains in clinical attachment levels after treatment significantly differed amongst the 3 groups-Caucasians responded most favorably, followed by African-Americans, lastly Hispanics, while numbers of P. gingivalis were highest in Hispanics, followed by African-Americans, and lowest in Caucasians (p = 0.015). However, no statistical differences were found in the numbers of S. cristatus amongst the 3 groups. Conclusion: Differential response to nonsurgical periodontal treatment and distribution of P. gingivalis are present in different ethnic/racial groups with periodontitis.

3.
Front Cell Infect Microbiol ; 13: 1137067, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36875522

RESUMO

The present study aimed at identifying risk factors associated with periodontitis development and periodontal health disparities with emphasis on differential oral microbiota. The prevalence of periodontitis is recently rising dentate adults in the US, which presents a challenge to oral health and overall health. The risk of developing periodontitis is higher in African Americans (AAs), and Hispanic Americans (HAs) than in Caucasian Americans (CAs). To identify potentially microbiological determinations of periodontal health disparities, we examined the distribution of several potentially beneficial and pathogenic bacteria in the oral cavities of AA, CA, and HA study participants. Dental plaque samples from 340 individuals with intact periodontium were collected prior to any dental treatment, and levels of some key oral bacteria were quantitated using qPCR, and the medical and dental histories of participants were obtained retrospectively from axiUm. Data were analyzed statistically using SAS 9.4, IBM SPSS version 28, and R/RStudio version 4.1.2. Amongst racial/ethnic groups: 1) neighborhood medium incomes were significantly higher in the CA participants than the AA and the HA participants; 2) levels of bleeding on probing (BOP) were higher in the AAs than in the CAs and HAs; 3) Porphyromonas gingivalis levels were higher in the HAs compared to that in the CAs; 4) most P. gingivalis detected in the AAs were the fimA genotype II strain that was significantly associated with higher BOP indexes along with the fimA type IV strain. Our results suggest that socioeconomic disadvantages, higher level of P. gingivalis, and specific types of P. gingivalis fimbriae, particularly type II FimA, contribute to risks for development of periodontitis and periodontal health disparities.


Assuntos
Fímbrias Bacterianas , Microbiota , Adulto , Humanos , Estudos Retrospectivos , Genótipo , Boca
4.
Front Cell Infect Microbiol ; 11: 789919, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34869082

RESUMO

Periodontitis disproportionately affects different racial and ethnic populations. In this study, we used qPCR to determine and compare oral microbial profiles in dental plaque samples from 191 periodontitis patients of different ethnic/racial backgrounds. We also obtained the periodontal parameters of these patients retrospectively using axiUm and performed statistical analysis using SAS 9.4. We found that in this patient cohort, neighborhood median incomes were significantly higher among Caucasians Americans (CAs) than among African Americans (AAs) and Hispanic Americans (HAs). Levels of total bacteria and Porphyromonas gingivalis, a keystone periodontal pathogen, were not evenly distributed among the three groups. We confirmed our previous findings that Streptococcus cristatus reduces P. gingivalis virulence potential and likely serves as a beneficial bacterium. We also showed the ratio of S. cristatus to P. gingivalis to be significantly higher in CAs than in HAs and AAs. Our results suggest that higher levels of P. gingivalis and lower ratios of S. cristatus to P. gingivalis may contribute to periodontal health disparities.


Assuntos
Periodontite , Humanos , Periodontite/epidemiologia , Porphyromonas gingivalis/genética , Estudos Retrospectivos , Fatores de Risco , Virulência
5.
Front Med (Lausanne) ; 7: 571069, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33251228

RESUMO

Objectives: The 2019 novel coronavirus disease (COVID-19) pandemic is the biggest public health crises in the 21st century. While most patients infected with the COVID-19 virus have no to moderate symptoms, there is currently limited clinical information about these patients. Methods: In this study, we retrospectively investigated 41 patients infected with the COVID-19 virus in Nanchang, Jiangxi province, China, from February 4 to March 2, 2020. Nanchang is about 260 km southeast of Wuhan, the initial epicenter of the COVID-19 pandemic. We retrieved information on patient demographics, physical examination results, epidemiology, clinical manifestations, underlying conditions, laboratory analyses, radiological images, and treatment outcomes. Results: Most patients (70.7%) had a history of close contact with patients with confirmed COVID-19, and 16 patients (39.0%) showed a high degree of family clustering. All 41 patients had no to moderate symptoms. The median age was 39.9 years and common symptoms of illness were fever (69.2%), cough (65.4%), and fatigue (19.2%). The dominant patient group was middle-aged women, with hypertension (14.6%) and chronic liver disease (12.2%) as the most frequent underlying conditions. All patients recovered, with the mean time of viral nucleic acid clearance at 10.6 days. Chest CT scans presented ground-glass opacities in 53.7% of patients while 26.8% had normal CT images. Laboratory results showed that lymphocyte counts, lymphocyte percentages, ESR, CRP, IgG, Fib, and cytokines were correlated to patients' conditions. Approximately 60-90% of patients had abnormally high levels of cytokines IL-4, IL-6, IL-10, and/or TNF-α. Conclusions: Our results showed variable clinical and laboratory presentations among this group of patients infected with the COVID-19 virus. Though all 41 patients recovered, our results suggest that cytokine levels and other biochemical indicators should be monitored for patients infected with the COVID-19 virus showing no to moderate symptoms to ensure quick access for critical medical attention, if needed.

6.
Curr Microbiol ; 77(8): 1532-1539, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32246181

RESUMO

Pseudomonas aeruginosa is a serious nosocomial pathogen with high morbidity and mortality due to the increasing resistance to antibiotics in recent years. qnrVC genes have been proven as a source of antibiotic resistance, but relationship with Pseudomonas aeruginosa remains not clear. We aimed to investigate the prevalence and molecular characteristics of qnrVC genes in P. aeruginosa clinical isolates. A total of 874 nonduplicate clinical isolates were collected in Guangdong, China, between January 2011 and June 2015. The presence of qnrVC genes and their genotypes were determined using PCR amplification and DNA sequencing. Antibiotic susceptibilities were tested, and the genetic relatedness of qnrVC-positive isolates were analyzed by multi-locus sequence typing (MLST) and pulsed field gel electrophoresis (PFGE). Consequently, we found 2.3% of P. aeruginosa isolates were present with qnrVC genes, displaying more resistant to various antibiotics. Phylogenetic analysis of qnrVC-positive strains revealed that antibacterial resistance among qnrVC-positive P. aeruginosa isolates in Guangdong probably emerged from multiple sources and was not spread by clonal strains.


Assuntos
Proteínas de Bactérias/genética , Infecções por Pseudomonas/epidemiologia , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana , China/epidemiologia , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla/genética , Feminino , Genótipo , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Filogenia , Prevalência , Pseudomonas aeruginosa/classificação , Pseudomonas aeruginosa/efeitos dos fármacos
7.
Sci Rep ; 9(1): 15600, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31666625

RESUMO

Human derived composite amnion-chorion membrane (ACM) has been used to facilitate wound healing due to reported anti-inflammatory properties and promotion of cell proliferation. This study aimed to assess the antimicrobial properties of the ACM using novel methods to visualize the antimicrobial efficacy of membranes in situ at different time points. Porcine Pericardium Collagen Membranes (PPCM) served as membrane controls. Circular pieces of the membranes were used in three different assays: insert, agar contact and glass-bottom well assays. Streptococcus gordonii were spotted onto the membranes and the plates were subsequently centrifuged to ensure direct bacterial contact with the membranes in the insert and agar contact assays, thus better mimicking bacterial adherence in the oral cavity. After incubation at 37 °C for 8, 24, and 48 hours, the membranes were dyed with the Live/Dead BacLight Bacterial Viability fluorescence stain and analyzed via confocal microscopy. The results demonstrated that the ACM completely inhibited bacterial growth at all time points, whereas the PPCM did not demonstrate any antimicrobial properties. Within the limits of this study, the ACM showed extremely high antimicrobial efficacy against oral streptococci. In addition, our methods may be useful in assessing antimicrobial properties for biomaterials with minimum diffusion ability, when traditional assessment methods are not applicable.


Assuntos
Âmnio/metabolismo , Córion/metabolismo , Streptococcus gordonii/fisiologia , Âmnio/diagnóstico por imagem , Animais , Córion/diagnóstico por imagem , Humanos , Viabilidade Microbiana , Microscopia Confocal , Suínos
8.
Med Sci Monit ; 24: 8033-8041, 2018 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-30412518

RESUMO

BACKGROUND Recent studies have shown that some members of the tripartite motif-containing protein (TRIM) family function as important regulators in several tumors. However, the clinical significance of TRIM15 in gastric adenocarcinoma has not been elucidated. In the present study, we aimed to examine the expression pattern of TRIM15 and explore whether the TRIM15 expression is correlated with clinicopathological characteristics of patients with gastric adenocarcinoma. MATERIAL AND METHODS The expression pattern of TRIM15 was examined in gastric adenocarcinoma tissues and adjacent normal stomach tissues by using immunohistochemistry staining. The prognostic role of TRIM15 in gastric cancer patients was evaluated by univariate and multivariate analyses. Clinical outcomes were assessed by the Kaplan-Meier analysis and log-rank test. The effects of TRIM15 on cancer cell proliferation and invasion were tested through cellular experiments. RESULTS TRIM15 was highly expressed in normal stomach tissues compared to tumor tissues. TCGA database showed that higher TRIM15 RNA transcription indicates poorer overall survival of gastric cancer patients. Besides, low expression of TRIM15 was significantly associated with advanced tumor invasion depth and advanced TNM stage. Moreover, gastric cancer patients with lower KDM5B expression had poorer overall survival, and TRIM15 was identified as an independent prognosis factor according to multivariate analysis. Using the gastric cancer cell lines, we found that overexpression of TRIM15 can inhibits tumor cell invasion. CONCLUSIONS Our study demonstrated that low expression of TRIM15 in gastric adenocarcinoma tissues was significantly associated with poorer prognosis of patients, indicating the potential of TRIM15 as a novel clinical biomarker and therapeutic target.


Assuntos
Proteínas de Ligação a DNA/biossíntese , Neoplasias Gástricas/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Adulto , Idoso , Biomarcadores Tumorais/metabolismo , Proliferação de Células/genética , Proteínas de Ligação a DNA/genética , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Invasividade Neoplásica , Prognóstico , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia
9.
Sci Rep ; 8(1): 1495, 2018 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-29367679

RESUMO

Cryptococcosis is a globally distributed infectious fungal disease. However, much remains unknown about its molecular epidemiology in many parts of the world. In this study, we analyzed 86 clinical Cryptococcus neoformans isolates from 14 regions in Jiangxi Province in south central China. Each isolate was from a different patient and 35 of the 86 (40.7%) patients were infected with HIV. All strains belonged to serotype A and mating type α (MATα). Genotyping based on DNA sequences at seven nuclear loci revealed eight sequence types (STs) among the 86 isolates, including two novel STs that have not been reported from other parts of the world. ST5 was the dominant genotype and our comparative analyses showed that these genotypes in Jiangxi likely originated by dispersal from other regions within and outside of China and/or mutations from another genotype within Jiangxi. Though none of the isolates was resistant to the five tested antifungal drugs (flucytosine, amphotericin B, fluconazole, itraconazole, and voriconazole), obvious differences in their minimum inhibitory concentrations were observed, even among isolates of the same ST. Our results suggest that continuous monitoring should be conducted to understand the changing dynamics of C. neoformans in this and other regions.


Assuntos
Antifúngicos/farmacologia , Criptococose/epidemiologia , Cryptococcus neoformans/genética , Farmacorresistência Fúngica/genética , Genes Fúngicos Tipo Acasalamento , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , China/epidemiologia , Criptococose/genética , Criptococose/microbiologia , Cryptococcus neoformans/classificação , Cryptococcus neoformans/isolamento & purificação , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Filogenia , Sorotipagem , Adulto Jovem
10.
Biomed Res Int ; 2015: 610281, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26583119

RESUMO

As one tumor marker of HCC, Golgi Protein 73 (GP73) is given more promise in the early diagnosis of HCC, and aptamers have been developed to compete with antibodies as biorecognition probes in different detection system. In this study, we utilized GP73 to screen specific ssDNA aptamers by SELEX technique. First, GP73 proteins were expressed and purified by prokaryotic expression system and Nickle ion affinity chromatography, respectively. At the same time, the immunogenicity of purified GP73 was confirmed by Western blotting. The enriched ssDNA library with high binding capacity for GP73 was obtained after ten rounds of SELEX. Then, thirty ssDNA aptamers were sequenced, in which two ssDNA aptamers with identical DNA sequence were confirmed, based on the alignment results, and designated as A10-2. Furthermore, the specific antibody could block the binding of A10-2 to GP73, and the specific binding of A10-2 to GP73 was also supported by the observation that several tumor cell lines exhibited variable expression level of GP73. Significantly, the identified aptamer A10-2 could distinguish normal and cancerous liver tissues. So, our results indicate that the aptamer A10-2 might be developed into one molecular probe to detect HCC from normal liver specimens.


Assuntos
Biomarcadores Tumorais/genética , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Proteínas de Membrana/genética , Anticorpos/genética , Aptâmeros de Nucleotídeos/genética , Carcinoma Hepatocelular/diagnóstico , Linhagem Celular Tumoral , DNA de Cadeia Simples/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/diagnóstico , Técnica de Seleção de Aptâmeros
11.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 31(2): 255-8, 2015 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-25652870

RESUMO

OBJECTIVE: To prepare the polyclonal antibodies against Golgi protein 73 (GP73) and preliminarily establish the particle-enhanced turbidimetric immunoassay. METHODS: New Zealand rabbits were immunized with recombinant GP73 protein to obtain the polyclonal antibodies. The antibodies were purified and covalently attached to latex particles. Under the optimized reaction conditions, the covalent latex-antibody complexes were prepared to establish the GP73 particle-enhanced turbidimetric immunoassay. RESULTS: The titer of purified polyclonal antibodies reached 16 000. The best reaction conditions were that the concentration of EDAC/NHS was 10 mg/mL, the reaction solution was PBS (pH6), reaction time was 3 hours at room temperature. Under such conditions, the coupling efficiency was the highest. The particle-enhanced turbidimetric assay showed a good specificity and sensitivity with a good linear relationship in the range of 6.25-200 ng/mL. The determination limit was 10 ng/mL. CONCLUSION: The study has successfully purified anti-GP73 antibodies, prepared the covalent latex-antibody complexes and established particle-enhanced turbidimetric immunoassay.


Assuntos
Anticorpos/análise , Imunoensaio/métodos , Neoplasias Hepáticas/sangue , Proteínas de Membrana/imunologia , Animais , Anticorpos/imunologia , Humanos , Imunoensaio/instrumentação , Neoplasias Hepáticas/diagnóstico , Proteínas de Membrana/sangue , Coelhos
12.
J Colloid Interface Sci ; 428: 141-5, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24910046

RESUMO

Rare-earth-doped LaPO4 crystals have been attracting considerable interest. In this work, we reported the fast syntheses of LaPO4 and Eu-doped LaPO4 crystals via a simple oil-bath route, employing La(NO3)3 and KH2PO4 as the original reactants, Eu2O3 as the dopant. The reaction was carried out in ethylene glycol system at 120°C for 30 min without any assistance of surfactants or templates. X-ray powder diffraction analyses showed that pure monoclinic LaPO4 form was obtained in the system without Eu(3+) ions, and the above phase was not changed after integrating Eu(3+) ions into LaPO4 matrix. However, electron microscopy observations discovered that the integration of Eu(3+) ions into LaPO4 matrix obviously changed the morphology and size of the final La(1-x)Eu(x)PO4 crystals. With the increase in Eu(3+) amount from 0 to 0.35, the shape of the final product varied from homogeneous egg-like nanospheroids, to irregular grains with microscales, and to homogeneous microspheroids. Also, the Eu(3+) ion content in La(1-x)Eu(x)PO4 markedly affected the photoluminescence properties of the final product. When x=0.2, the product exhibited the strongest PL emission.

13.
J Nanosci Nanotechnol ; 14(7): 5529-34, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24758061

RESUMO

SnO2:Eu3+ nanorods have been successfully synthesized by annealing products from microwave-induced KCl-assisted solution combustion reaction, which uses tin (IV) chloride pentahydrate and europium nitrate as cationic source, ethyl glycol as fuel and ammonium nitrate as combustion-supporting agent. The structural and photoluminescent properties of SnO2:Eu3+ nanorods were investigated by high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), selected area electron diffractometry (SAED), X-ray diffractometry (XRD) and photoluminescence spectroscopy. The phase transformation in the synthetic process was observed by X-ray diffraction pattern. Accordingly, the growth mechanism of SnO2:Eu3+ nanorods was discussed. The results showed that the SnO2:Eu3+ nanorods were rutile-structured single crystals with 10-15 nm in diameter and 200-250 nm in length. Proper addition of KCl into redox mixture solution is critical to the formation of SnO2:Eu3+ nanorods. The doped Eu3+ concentration has obvious effect on the photoluminescence of SnO2:Eu3+ nanorods. The approach is convenient, inexpensive and efficient for the high yield preparation of SnO2:Eu3+ nanorods.

14.
J Int Acad Periodontol ; 14(3): 56-61, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22908534

RESUMO

OBJECTIVE: To determine if a novel formulation is effective in killing oral biofilm streptococci in vitro and in vivo. METHODS: Efficacy of 0.5% levulinic acid and 0.05% sodium dodecyl sulfate (SDS) in killing Streptococcus gordonii CH1, Streptococcus gordonii DL1, Streptococcus mitis NCTC10712, Streptococcus oralis KS32AR, Streptococcus mutans BM71, and Streptococcus mutans GS5 in their biofilm form was measured in vitro, using microtiter plates and subsequent counts on Mitis-Salivarius agar plates. The safety and efficacy in vivo were evaluated using a mouse model. RESULTS: Our anti-microbial formulation completely eliminated all the biofilm streptococcal species tested within 30 seconds (a reduction of 10(7) CFU/ml), whereas the positive control Listerine only demonstrated moderate reduction in vitro. Application of the formulation twice a day for 7 days in the murine oral cavity resulted in significantly more reduction of established S. gordonii DL1 oral biofilm bacteria than Listerine. The formulation did not cause any adverse effect in the murine oral cavity within a 2-week period. CONCLUSIONS: We have demonstrated that the novel mouth rinse exhibits high efficacy in killing oral bacteria in their biofilm forms, results in no adverse effect in vivo, and contains alcohol-free components.


Assuntos
Placa Dentária/microbiologia , Antissépticos Bucais/química , Antissépticos Bucais/farmacologia , Streptococcus/efeitos dos fármacos , Animais , Biofilmes/efeitos dos fármacos , Contagem de Colônia Microbiana , Combinação de Medicamentos , Ácidos Levulínicos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Segurança , Dodecilsulfato de Sódio/farmacologia
15.
J Environ Sci (China) ; 24(12): 2180-90, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23534216

RESUMO

Sulfated BiWO (SBiWO) was synthesized by an impregnation method to enhance the visible-light-driven photoactivities of BiWO (BiWO). The characterization results verified that sulfate anion mainly anchored on the catalyst surface greatly extended the visible-light-responsive range without destroying the crystal lattice. Moreover, the SBiWO-based photoactivities were evaluated with the removal of Malachite Green (MG) under UV-Vis irradiation emitted from two microwave-powered electrodeless discharge lamps (MPEDL2) and under visible light (lamda > 420 nm). The results demonstrated that the kinetic constant was increased 2.25 times, varying from 0.1478 (BiWO) to 0.3328 min(-1) (SBiWO-1). Similar results were also obtained for the visible light-driven reaction. Furthermore, radical scavengers such as t-butanol restricted the visible-light induced degradation of MG over BiWO and SBiWO-1. This indicated that the sulfating process increased the generation of reactive oxygen species, which was further verified by molecular probe with salicylic acid. Thus, more blue-shifting at lam = 618 nm was observed over SBiWO. On the basis of the above results, the photocatalytic mechanism over the sulfated catalyst was also discussed.


Assuntos
Bismuto/química , Poluentes Ambientais/química , Fotólise , Corantes de Rosanilina/química , Ésteres do Ácido Sulfúrico/síntese química , Catálise , Poluentes Ambientais/efeitos da radiação , Corantes de Rosanilina/efeitos da radiação , Raios Ultravioleta
16.
Chem Commun (Camb) ; 47(20): 5891-3, 2011 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-21487616

RESUMO

Urchin-like Ni-P microstructures with room-temperature magnetism have been successfully synthesized via a simple water-DMF solvothermal route. The as-obtained product exhibits good capacity to rapidly remove heavy-metal ions such as Cd(2+) and Pb(2+) ions from water and can be easily recycled owing to their magnetism.

17.
J Colloid Interface Sci ; 356(2): 490-5, 2011 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-21329936

RESUMO

In this paper, LaPO(4) nanorods have been successfully synthesized via a simple water-ethyleneglycol (H(2)O-EG) mixed-solvothermal route, employing lanthanum nitrate (La(NO(3))(3)·xH(2)O) as a La(3+) ion source and monobasic sodium phosphate (NaH(2)PO(4)·2H(2)O) as a PO(4)(3-) ion source. The as-obtained products were characterized by means of X-ray powder diffraction (XRD), energy dispersive spectrometry (EDS), (high resolution) transmission electron microscopy (HR/TEM), selected area electron diffraction (SAED) and field emission scanning electron microscopy (FESEM). Some factors influencing the formation of LaPO(4) nanorods, including the reaction temperature, the volume ratio of water/EG and the original amount of H(2)PO(4)(-) ions, were investigated. Experiments showed that the volume ratio of water/EG and the original amount of H(2)PO(4)(-) ions could markedly affect the morphology of the final product.

18.
Nanoscale ; 3(1): 196-200, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21049133

RESUMO

In this paper, we employed a facile hydrothermal route to successfully synthesize nanosized nickel phosphide particles with controlled phases via selecting different surfactants at different temperatures and times. The phases of the as-obtained products were determined by X-ray powder diffraction (XRD) patterns and Rietveld refinement of XRD data. The morphologies of the products were characterized by (high resolution) transmission electron microscopy (HR/TEM) and field emission scanning electron microscopy (FESEM). Experiments indicated that pure Ni2P phase could be prepared when nontoxic red phosphorus and nickel dichloride were used as starting materials in the presence of polyvinylpyrrolidone (PVP, 30 K), sodium dodecylbenzene sulfonate (SDBS), cetyltrimethylammonium bromide (CTAB) or polyethylene glycol 10000 (PEG-10000) at 160 °C for 10 h. When acrylamide (AM) was selected as the surfactant, however, pure Ni12P5 phase could be prepared by prolonging the reaction time to 20 h at 160 °C, or enhancing the reaction temperature to 180 °C for 10 h. Furthermore, the experiments indicated that the pure Ni2P phase possessed a stronger photocatalytic degradation ability than the pure Ni12P5 phase.


Assuntos
Nanopartículas/química , Níquel/química , Fósforo/química , Benzenossulfonatos/química , Catálise , Cetrimônio , Compostos de Cetrimônio/química , Nanopartículas/ultraestrutura , Tamanho da Partícula , Fotólise , Polietilenoglicóis/química , Povidona/química , Temperatura , Difração de Raios X
19.
J Nanosci Nanotechnol ; 10(10): 6465-72, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21137748

RESUMO

Single-crystalline NbSe2 nanobelt, nanorod (containing nanotube), and microplate films were grown on Nb substrates by a surface-assisted chemical-vapor-transport (CVT), respectively. The nanobelts have a rectangular section of 50 x 250 to 300 x 4500 nm2, and a length up to 330 microm. The nanorods have a hexagonal section with a diameter of about 0.1-0.5 microm, and a length up to 15 microm. The nanotubes have rectangular, pentagonal or round sections with a diameter of about 0.4-0.5 microm, a tube-wall thickness of about 45 nm, and a length up to several microns. The microplates have a hexagonal section with a diameter of about 0.05-10 microm and a thickness of about 100 to 600 nm. Field-emission experiments using the films as cold electron cathodes showed that they had notable emission currents and low turn-on fields, suggesting their potential applications in field emission devices.

20.
Ultrason Sonochem ; 17(3): 509-14, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19751989

RESUMO

In the present paper, we reported the successful synthesis of dumbbell-like YF(3) nanostructures with a high yield in a mixed system of water/N,N-dimethylformamide (DMF) under the assistance of ultrasound waves of 40kHz with the ultrasonic power of 100% (200W) at 65 degrees C for 2h, employing Y(2)O(3) (99.99%) and NH(4)F as the starting reactants. The product was characterized by means of powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), selected area electron diffraction (SAED) pattern and field-emission scanning electron microscopy (SEM). Some factors influencing the morphology of YF(3) nanostructures, including the ultrasonic time and power, the amount of NH(4)F, and the ratio of water/DMF, were systematically investigated. Research showed that the morphology of YF(3) could be tuned by the volume ratio of water/DMF. The roles of DMF and the ultrasonic wave in the formation of YF(3) nanostructures were discussed.


Assuntos
Fluoretos/química , Nanoestruturas/química , Ultrassom , Ítrio/química , Dimetilformamida/química , Cinética , Microscopia Eletrônica de Varredura , Água/química , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...