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1.
J Nanosci Nanotechnol ; 20(6): 3568-3575, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31748053

RESUMO

Ultrafine nanoporous copper (UNP Cu) with a characteristic pore size of about 12 nm and a ligament size of about 14 nm was fabricated from amorphous Mg65Cu25Y10 precursor alloys after dealloying in a 0.1 M H2SO4 solution modified by poly(vinyly alcohol) polymers with a molecular weight of 105000 g/mol (PVA-124). The suppression of the surface diffusion from PVA-124 reduced the size of the nanopores and ligaments to 20 nm when the concentration of the added PVA-124 exceeded 0.1 g L-1. When the concentration of the added PVA-124 exceeded 2 g L-1, PVA-124 triggered the polymerization process. The resultant polymer surface layer on the fcc Cu ligaments was shown to reduce the rate of selective dissolution. It was also shown that extending the immersion time resulted in a suppression of coarsening. The introduction of PVA-124 polymer into acids resulted in a higher viscosity of the dealloying solutions, particularly when the concentration of PVA-124 was higher than 1.0 g L-1. This viscosity was shown not only to reduced rate of diffusion of Cu adatoms in PVA-124 solutions, but also forced the accumulation of Cu adatoms to form small scale UNP Cu.

2.
Emerg Microbes Infect ; 8(1): 367-376, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31851879

RESUMO

The dimorphic fungus Talaromyces marneffei (TM) is a common cause of HIV-associated opportunistic infections in Southeast Asia. Cotrimoxazole (CTX) inhibits folic acid synthesis which is important for the survival of many bacteria, protozoa, and fungi and has been used to prevent several opportunistic infections among HIV/AIDS patients. We question whether CTX is effective in preventing TM infection. To investigate this question, we conducted an 11-year (2005-2016) retrospective observational cohort study of all patients on the Chinese national antiretroviral therapy (ART) programme in Guangxi, a province with high HIV and TM burden in China. Survival analysis was conducted to investigate TM cumulative incidence, and Cox regression and propensity score matching (PSM) were used to evaluate the effect of CTX on TM incidence. Of the 3359 eligible individuals contributing 10,504.66 person-years of follow-up, 81.81% received CTX within 6 months after ART initiation, and 4.73% developed TM infection, contributing 15.14/1,000 person-year TM incidence rate. CTX patients had a significantly lower incidence of TM infection than non-CTX patients (4.11% vs. 7.53%; adjusted hazard ratio (aHR) = 0.50, 95% CI 0.35-0.73). CTX reduced TM incidence in all CD4+ cell subgroups (<50 cells/µL, 50-99 cells/µL, 100-199 cells/µL), with the highest reduction observed in patients with a baseline CD4+ cell count <50 cells/µL in both Cox regression and the PSM analyses. In conclusion, in addition to preventing other HIV-associated opportunistic infections, CTX prophylaxis has the potential to prevent TM infection in HIV/AIDS patients receiving ART.

3.
Nanomaterials (Basel) ; 9(5)2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31091819

RESUMO

Evolution behavior of the nanoporous architectures has been investigated via potentiostatic electrochemical dealloying of dual-phase AgxSn100-x (x = 20, 30, 40 at.%) alloys, which consist of ß-Sn and ε-Ag3Sn phases with different volume fractions in 1.2 M HCl solution. The results show that the open-circuit potentials and corrosion potentials of dual-phase Ag-Sn alloys are determined by the less noble ß-Sn phases rather than chemical compositions of the Ag-Sn precursor alloys. The potentiodynamic polarization curves show that the anodic dissolution of Ag-Sn alloys is divided into two stages including the first preferential dissolution of ß-Sn phases and secondary dealloying of ε-Ag3Sn phases, which is associated with the order of the nanoporous evolution. Nanoporous silver (NPS) can be fabricated by potentiostatic dealloying of dual-phase Ag-Sn alloys in HCl solution. The dealloying of two phases is asynchronous: The less noble ß-Sn phases are preferentially etched to generate the larger pores, and then the more noble ε-Ag3Sn phases are dealloyed to form the finer nanoporous structure. The significant surface diffusion of Ag adatoms at the applied potential higher than the pitting potential of ε-Ag3Sn phases during the dealloying results in the coarsening of nanoporous ligaments with a time dependence of d(t) ∝ t0.1. The fractions and the difference in electrochemical stabilities of the ß-Sn and ε-Ag3Sn phases in dual-phase AgxSn100-x (x = 20, 30, 40 at.%) precursor alloys determines the final nanoporous structure.

4.
Sci Rep ; 9(1): 7816, 2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31127157

RESUMO

Previous studies investigating HIV-infected patients suggested a direct link between underweight and the mortality rate of AIDS. However, there was a lack of evidence showing the optimal range of initial body mass index (BMI) patients maintain during antiretroviral therapy (ART). We aimed to evaluate associations of the BMI values pre-ART and during the entire ART duration with mortality among HIV-positive individuals. In total, 5101 HIV/AIDS patients, including 1439 (28.2%) underweight, 3047 (59.7%) normal-weight, 548 (10.7%) overweight and 67 (1.3%) obese patients, were included in this cohort. The cumulative mortality of underweight, normal-weight, and overweight were 2.4/100 person-years (95% CI 1.9-2.9), 1.1/100 person-years (95% CI 0.9-1.3), and 0.5/100 person-years (95% CI 0.1-0.9), respectively. Cumulative mortality was lower in both the normal-weight and overweight populations than in the underweight population, with an adjusted hazard ratio (AHR) of 0.5 (95% CI 0.4-0.7, p < 0.001) and 0.3 (95% CI 0.1-0.6, p = 0.002), respectively. Additionally, in the 1176 patients with available viral load data, there was significant difference between the underweight and normal-weight groups after adjustment for all factors, including viral load (p = 0.031). This result suggests that HIV-infected patients in Guangxi maintaining a BMI of 19-28 kg/m2, especially 24-28 kg/m2, have a reduced risk of death.

5.
BMJ Open ; 9(4): e023140, 2019 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-30944128

RESUMO

OBJECTIVE: To characterise the association between duration of exposure to antiretroviral treatment (ART) and liver damage in HIV patients with an initially normal baseline liver function and without hepatitis B virus (HBV)/hepatitis C virus (HCV) infection. METHODS: A retrospective cohort study was conducted in HIV-infected individuals with normal liver function parameters at ART initiation and without HBV/HCV infection, from 14 April 2004 to 13 April 2015 in Guigang city, Guangxi, China. The association between duration of ART and liver damage (grade II-IV liver enzyme elevation [LEE] and/or total bilirubin elevation [TBE]), was analysed. Cox regression was used to examine the factors related to liver damage. RESULTS: Of 2119 eligible patients, 12.41% (263/2119) developed liver damage (grade II-IV LEE/TBE) and contributed 4.11/100 person-years crude incidence rate. The highest liver damage incidence was observed in patients with 6-12 months' ART (15.16/100 person-years). The incidence decreased to 5.56/100 person-years in patients with 12-18 months' ART and 3.13/100 person years in patients with 18-24 months' ART, and then maintained at a relatively low and stable level in patients with 2 years' ART or longer (average of 3.65/100 person-years). Cox regression analysis revealed that current WHO disease stage II, III or IV (compared with stage I) were the risk factors for liver damage, while baseline disease stage II, III (compared with stage I) and current regimen 3TC+AZT+NVP were the protective factors for liver damage. CONCLUSIONS: Liver damage always exists among HIV-infected patients on ART with normal baseline liver function and without HBV/HCV infection. Nevertheless, cumulative ART duration does not increase the risk of liver damage. ART could tend to be long-term, however, monitoring and management of liver damage among patients on ART are also important in clinical therapy.

6.
J Nanosci Nanotechnol ; 19(7): 3825-3831, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30764940

RESUMO

Novel Ti-Cu-O nanotubes with the diameter of approximately 22 nm, the length of about 360 nm and the wall thickness of approximately 6 nm, were in-situ fabricated by one-step anodic oxidation of Ti60Cu40 amorphous alloy in the ethylene glycol containing F-. The Ti-Cu-O nanotubes exhibited superior electrocatalytic performance for glucose oxidation with an ultrahigh sensitivity of 403.9 µA cm-2 mM-1 in a linear range covering from 10 µM to 0.2 mM and low detection limit of 1.40 µM (at signal/noise ratio (S/N) = 3) at the potential of 0.6 V (vs. SCE). Moreover, the Ti-Cu-O nanotubes demonstrated a long-term stability and a good selectivity to uric acid and ascorbic acid. The superior catalytic performance of Ti-Cu-O nanotubes is attributed to the synergistic effect of Cu species existence in different valences and the tubular microstructure with large specific area. All results suggest that the Ti-Cu-O nanotubes could be potential materials for non-enzymatic glucose sensor.

7.
Cell Death Dis ; 9(9): 898, 2018 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-30185779

RESUMO

Both alcohol and hepatitis C virus (HCV) infection could induce cellular autophagy in liver cells, which is considered to be essential for productive HCV replication. However, whether alcohol-induced autophagy is involved in the pathogenesis of HCV infection is still poorly understood. Alcohol treatment could induce autophagy in Huh7 cells (a hepatoma cell line that supports HCV JFH-1 replication), evidenced by the increase of LC3B-II levels, the conversion of LC3B-I to LC3B-II, and the formation of GFP-LC3 puncta as well as the decrease of p62 level in alcohol-treated cells compared with control cells. Alcohol treatment also significantly increased PIASy (a member of the PIAS family) expression, which can act as a SUMO (small ubiquitin-like modifier protein) E3 ligase to regulate a broader range of cellular processes including autophagy. Overexpression or the silencing expression of PIASy in alcohol-treated Huh7 cells could increase or decrease autophagic activation caused by alcohol treatment, respectively, and thus affect HCV replication correspondingly. In the absence of alcohol, overexpression or silencing expression of PIASy increase or decrease the level of cellular autophagy, judged by the changes of LC3B-II and p62 levels in the presence or absence of chloroquine (CQ), a lysosome inhibitor. More importantly, in the presence of 3-methyladenine (3-MA), an inhibitor in the early stage of autophagy, the effects of overexpression or silencing expression of PIASy on HCV replication were largely blocked. Furthermore, PIASy could selectively drive the accumulation of SUMO1-conjugated proteins, along with upregulation of the expression of several important autophagy factors, including ATG7 and ATG5-ATG12. In conclusion, alcohol promotes HCV replication through activation of autophagy in Huh7 cells, which partly attributes to its induction of PIASy expression. PIASy-enhanced accumulation of SUMO1-conjugated proteins may contribute to its inducing effect of autophagy. Our findings provide a novel mechanism for the action of alcohol-promoting HCV replication in the context of cellular autophagy.


Assuntos
Autofagia/efeitos dos fármacos , Carcinoma Hepatocelular/genética , Etanol/farmacologia , Hepacivirus/genética , Proteínas de Ligação a Poli-ADP-Ribose/genética , Proteínas Inibidoras de STAT Ativados/genética , Regulação para Cima/efeitos dos fármacos , Replicação Viral/genética , Carcinoma Hepatocelular/virologia , Linhagem Celular Tumoral , Hepatite C/genética , Hepatite C/virologia , Hepatócitos/virologia , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/virologia , Proteínas Associadas aos Microtúbulos/genética , Ativação Transcricional/genética
8.
Nanomaterials (Basel) ; 8(8)2018 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-30061477

RESUMO

Nanoporous golf ball-shaped powders with a surface porous layer consisting of fcc Cu and Cu3Au phases have been fabricated by selectively dissolving gas-atomized Ti60Cu39Au1 powders in 0.13 M HF solution. The distribution profiles of the Ti2Cu and TiCu intermetallic phases and powder size play an important role of the propagation of the selective corrosion frontiers. The final nanoporous structure has a bimodal characteristic with a finer nanoporous structure at the ridges, and rougher structure at the shallow pits. The powders with a size of 18⁻75 m dealloy faster due to their high crystallinity and larger powder size, and these with a powder size of smaller than 18 m tend to deepen uniformly. The formation of the Cu3Au intermetallic phases and the finer nanoporous structure at the ridges proves that minor Au addition inhibits the fast diffusion of Cu adatoms and decreases surface diffusion by more than two orders. The evolution of the surface nanoporous structure with negative tree-like structures is considered to be controlled by a percolation dissolution mechanism.

9.
Gene ; 662: 21-27, 2018 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-29627523

RESUMO

BACKGROUND: Identification of new HIV infections (HIV incidence) is critical for monitoring AIDS epidemic and assessing the effectiveness of intervention measures. However, current methods for distinguishing new infections from newly diagnosed HIV-1 patients are still imperfect. We explored utilizing miRNAs as biomarker to identify HIV new infections. METHODS: According to the HIV-1 status and the estimated duration of infection (EDI), we enrolled participants and divided them into three groups: healthy control, new infection (within 1 year), and old infection (longer than 1 year). Participants were assigned into screening set or validation set. miRNA microarray was performed in screening set and the differentially expressed miRNAs were screened out. The differentially expressed miRNAs were further confirmed in validation set and HIV-1 IIIB-MT2 cells infection system. RESULTS: In screening set, 5 miRNAs including miR-1291, miR-3609, miR-3162-3p, miR-874-5p and miR-4258 were screened out for their differential expression in plasma among three groups. In validation set, down- trend of miR-3162-3p was validated from healthy control, new infection to old infection groups. In HIV-1 IIIB-MT2 system, the levels of miR-3162-3p also decreased along with infection duration in vitro. Sensitivity and specificity for miR-3162-3p to distinguish new infection from old infection were 100.0% and 71.43%, respectively, with the cut-off value of 0.916. CONCLUSION: miR-3162-3p in plasma could be a potential microRNA biomarker to identify HIV new infections in HIV-1 infected patients.


Assuntos
Infecções por HIV/diagnóstico , Infecções por HIV/genética , HIV-1/isolamento & purificação , MicroRNAs/sangue , Biomarcadores/sangue , Estudos de Casos e Controles , China , Feminino , Perfilação da Expressão Gênica , Infecções por HIV/sangue , Humanos , Masculino , MicroRNAs/genética , Sensibilidade e Especificidade
10.
BMC Public Health ; 18(1): 450, 2018 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-29618343

RESUMO

BACKGROUND: Female sex workers (FSW) are a population that are at high risk for HIV infection, and their HIV/AIDS knowledge levels and sexual behaviors are of concern. This study describes changes in HIV prevalence and factors associated among female sex workers in Guigang City, Guangxi, one of the highest HIV prevalence areas in China. METHODS: Data were derived from an annual cross-sectional venue-based survey, 2008 to 2015, in the form of sentinel surveillance. The participants were recruited using cluster sampling. FSW aged 16 years and above who completed a questionnaire and HIV testing. Both descriptive and multi-level analyses were used to explore factors associated with changes in HIV prevalence. RESULTS: Seven thousand four hundred ninety-six FSW were recruited in this study. HIV prevalence among FSW in Guigang City fell into two periods, one with an increasing trend (2008-2011) and one with a decline (2012-2015). Differences between these time periods included age, relationship status, HIV knowledge, consistent condom use, lifetime illicit drug use, history of sexually transmitted infection in the past year, HIV testing, receipt of a condom distribution and education program or HIV counseling and testing, and peer education services. CONCLUSIONS: Since 2012, a reduction in HIV prevalence among FSW in Guigang City has been observed. The decline of HIV prevalence was associated with coinciding changes in demographic characteristics of FSW, improvement of HIV knowledge and safer sexual behaviors, and a program that promotes condom use, HIV counseling & testing, and peer education.


Assuntos
Infecções por HIV/epidemiologia , Vigilância de Evento Sentinela , Profissionais do Sexo/estatística & dados numéricos , Adolescente , Adulto , China/epidemiologia , Estudos Transversais , Feminino , Humanos , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Inquéritos e Questionários , Adulto Jovem
11.
Materials (Basel) ; 11(3)2018 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-29562692

RESUMO

Thin cupric oxide (Cu2O) nanobelts with width of few tens of nanometers to few hundreds of nanometers were fabricated in anhydrous ethanol on nanoporous copper templates that was prepared via dealloying amorphous Ti40Cu60 ribbons in hydrofluoric acid solutions at 348 K. The Cu2O octahedral particles preferentially form in the water, and nanobelts readily undergo the growth along the lengthwise and widthwise in the anhydrous ethanol. The ethanol molecules serve as stabilizing or capping reagents, and play a key role of the formation of two-dimensional Cu2O nanobelts. Cu atoms at weak sites (i.e., twin boundary) on the nanoporous Cu ligaments are ionized to form Cu2+ cations, and then react with OH- to form Cu2O and H2O. The two-dimensional growth of Cu2O nanostructure is preferred in anhydrous ethanol due to the suppression of random growth of Cu2O nanoarchitectures by ethanol. Cu2O nanobelts have superior photodegradation performance of methyl orange, three times higher than nanoporous Cu.

12.
J Med Virol ; 90(6): 1112-1120, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29446489

RESUMO

Alcohol could compromise the anti-hepatitis C virus (HCV) function of interferon-alpha (IFN-α). However, little information is available about the effect of alcohol on interferon-lambda (IFN-λ, type III IFN), a novel candidate for development of therapy for HCV infection. Huh7 cells were infected with HCV JFH-1 virus, then treated with alcohol, and/or IFN-λ1. RT-PCR and Western blot were used to detect the levels of HCV and key cellular factors. Overexpression or silencing expression was performed to verify the role of key factors in alcohol-attenuated anti-HCV function of IFN-λ1. Alcohol treatment compromised anti-HCV effect of IFN-λ1 in HCV JFH-1-infected Huh7 cells, evidenced by the significantly increased levels of HCV RNA, and HCV core protein in alcohol-/IFN-λ1-treated cells compared to cells with IFN-λ1 treatment alone. Investigation of the mechanisms responsible for the alcohol action revealed that alcohol enhanced the expression of protein inhibitor of activated STAT (PIASy). Overexpression of PIASy compromised anti-HCV ability of IFN-λ1, whereas silencing expression of PIASy partly restored the alcohol-attenuated anti-HCV effect of IFN-λ1. More importantly, overexpression of PIASy significantly down-regulated the level of IFN-λ1-indcued phosphorylation of STAT1 (p-STAT1), an important adaptor in IFN-λ pathway, as well as reduced the expression of IFN-λ1-induced IFN-stimulated genes 56 (ISG56), and myxovirus resistance 1 (Mx1), two antiviral effectors in in IFN-λ pathway. These findings indicate that alcohol, through inducing the expression of negative regulator in IFN-λ pathway, inhibits IFN-λ-mediated anti-HCV action in human hepatic cells, which may lead to the poor efficacy of IFN-λ-based therapy against HCV infection.


Assuntos
Álcoois/metabolismo , Hepacivirus/imunologia , Hepatócitos/imunologia , Interleucinas/antagonistas & inibidores , Proteínas de Ligação a Poli-ADP-Ribose/biossíntese , Proteínas Inibidoras de STAT Ativados/biossíntese , Regulação para Cima , Western Blotting , Linhagem Celular , Perfilação da Expressão Gênica , Hepacivirus/crescimento & desenvolvimento , Hepatócitos/efeitos dos fármacos , Hepatócitos/virologia , Humanos , Interferons , RNA Viral/análise , Reação em Cadeia da Polimerase em Tempo Real , Proteínas do Core Viral/análise
13.
AIDS Patient Care STDS ; 31(9): 384-393, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28891716

RESUMO

In China, rural areas are a weak link of HIV/AIDS prevention and control. From September 2011, an innovative "county-township-village" allied intervention was implemented in Longzhou County, Guangxi, which assigned the tasks of HIV/AIDS prevention and control to the county Centers for Disease Control and Prevention (CDC), township hospitals, and village clinics, respectively, instead of traditional intervention in which the county CDC undertook the entire work. A 6-year consecutive cross-sectional survey, including 3-year traditional intervention (2009-2011) and 3-year innovative intervention (2012-2014), was conducted to evaluate the effects of the new intervention. Compared to traditional intervention, the innovative intervention achieved positive effects in decreasing risky behaviors. Among female sex workers, condom use rate in the last month increased from 72.06% to 96.82% (p < 0.01). Among drug users, having commercial sex rate in the last year reduced from 17.20% to 5.94% and condom use rate increased from 14.06% to 76.09% (p < 0.01). The risk ratio of HIV infection during innovative intervention was 0.631 (95% confidence interval 0.549-0.726) compared with traditional one. Cost-effectiveness analysis indicates that innovative intervention restores each disability-adjusted life year costing an average of $124.26. Taken together, Longzhou's innovative intervention has achieved good effects on HIV/AIDS prevention and control and provides a good reference for rural China.


Assuntos
Preservativos/estatística & dados numéricos , Infecções por HIV/prevenção & controle , Avaliação de Programas e Projetos de Saúde/métodos , População Rural , Sexo Seguro/estatística & dados numéricos , Profissionais do Sexo , Adulto , China/epidemiologia , Análise Custo-Benefício , Estudos Transversais , Feminino , Infecções por HIV/etnologia , Humanos , Pessoa de Meia-Idade , Assunção de Riscos , Trabalho Sexual
14.
Am J Trop Med Hyg ; 97(3): 799-805, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28820678

RESUMO

It is a daunting task to eradicate tuberculosis completely in Heng County due to a large transient population, human immunodeficiency virus/tuberculosis coinfection, and latent infection. Thus, a high-precision forecasting model can be used for the prevention and control of tuberculosis. In this study, four models including a basic autoregressive integrated moving average (ARIMA) model, a traditional ARIMA-generalized regression neural network (GRNN) model, a basic GRNN model, and a new ARIMA-GRNN hybrid model were used to fit and predict the incidence of tuberculosis. Parameters including mean absolute error (MAE), mean absolute percentage error (MAPE), and mean square error (MSE) were used to evaluate and compare the performance of these models for fitting historical and prospective data. The new ARIMA-GRNN model had superior fit relative to both the traditional ARIMA-GRNN model and basic ARIMA model when applied to historical data and when used as a predictive model for forecasting incidence during the subsequent 6 months. Our results suggest that the new ARIMA-GRNN model may be more suitable for forecasting the tuberculosis incidence in Heng County than traditional models.


Assuntos
Modelos Biológicos , Modelos Estatísticos , Tuberculose/epidemiologia , China/epidemiologia , Simulação por Computador , Humanos , Incidência
15.
Materials (Basel) ; 10(9)2017 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-28846622

RESUMO

Nanoporous structures were fabricated from Fe76Si9B10P5 amorphous alloy annealed at 773 K by dealloying in 0.05 M H2SO4 solution, as a result of preferential dissolution of α-Fe grains in form of the micro-coupling cells between α-Fe and cathodic residual phases. Nanoporous Fe-Si-B-P powders exhibit much better degradation performance to methyl orange and direct blue azo dyes compared with gas-atomized Fe76Si9B10P5 amorphous powders and commercial Fe powders. The degradation reaction rate constants of nanoporous powders are almost one order higher than those of the amorphous counterpart powders and Fe powders, accompanying with lower activation energies of 19.5 and 26.8 kJ mol-1 for the degradation reactions of methyl orange and direct blue azo dyes, respectively. The large surface area of the nanoporous structure, and the existence of metalloids as well as residual amorphous phase with high catalytic activity are responsible for the enhanced azo-dyes degradation performance of the nanoporous Fe-Si-B-P powders.

16.
Nanomaterials (Basel) ; 7(6)2017 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-28594378

RESUMO

Nanoporous electrodes have been fabricated by selectively dissolving the less noble α-Fe crystalline phase from nanocrystalline Fe85.2B14-xPxCu0.8 alloys (x= 0, 2, 4 at.%). The preferential dissolution is triggered by the weaker electrochemical stability of α-Fe nanocrystals than amorphous phase. The final nanoporous structure is mainly composed of amorphous residual phase and minor undissolved α-Fe crystals and can be predicted from initial microstructure of nanocrystalline precursor alloys. The structural inheritance is proved by the similarity of the size and outlines between nanopores formed after dealloying in 0.1 M H2SO4 and α-Fe nanocrystals precipitated after annealing of amorphous Fe85.2B14-xPxCu0.8 (x = 0, 2, 4 at.%) alloys. The Redox peak current density of the nanoporous electrodes obtained from nanocrystalline Fe85.2B10P4Cu0.8 alloys is more than one order higher than those of Fe plate electrode and its counterpart nanocrystalline alloys due to the large surface area and nearly-amorphous nature of ligaments.

17.
Nanomaterials (Basel) ; 8(1)2017 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-29301227

RESUMO

Two types of cupric oxide (Cu2O) nanoarchitectures (nanobelts and nanopetal networks) have been achieved via immersion nanoporous copper (NPC) templates in anhydrous ethanol. NPC templates with different defect densities have been prepared by dealloying amorphous Ti60Cu40 ribbons in a mixture solution of hydrofluoric acid and polyvinylpyrrolidone (PVP) with different ratios of HF/PVP. Both a water molecule reactant acting as OH- reservoir and the ethanol molecule serving as stabilizing or capping reagent for inhibiting the random growth of Cu2Oplayed a role of the formation of 2-dimensional Cu2O nanoarchitectures. Cu2O nanobelts are preferred to form in anhydrous ethanol on the NPC templates from Ti60Cu40 ribbons dealloying in the solution with low HF concentration and small addition of PVP; and Cu2O nanopetals are tended to grow in anhydrous ethanol from the NPC templates from Ti60Cu40 ribbons dealloying in the solution with high HF concentration and large addition of PVP. With increasing the immersion time in anhydrous ethanol, Cu2O nanopetals united together to create porous networks about 300 nm in thickness. The defect sites (i.e., twin boundary) on nanoporous Cu ligaments preferentially served as nucleation sites for Cu2O nanocrystals, and the higher defect density leads to the formation of uniform Cu2O layer. Synergistic effect of initial microstructure of NPC templates and stabilizing agent of ethanol molecule results in different Cu2O nanoarchitectures.

18.
PLoS One ; 11(6): e0156768, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27258555

RESUMO

BACKGROUND: Hepatitis is a serious public health problem with increasing cases and property damage in Heng County. It is necessary to develop a model to predict the hepatitis epidemic that could be useful for preventing this disease. METHODS: The autoregressive integrated moving average (ARIMA) model and the generalized regression neural network (GRNN) model were used to fit the incidence data from the Heng County CDC (Center for Disease Control and Prevention) from January 2005 to December 2012. Then, the ARIMA-GRNN hybrid model was developed. The incidence data from January 2013 to December 2013 were used to validate the models. Several parameters, including mean absolute error (MAE), root mean square error (RMSE), mean absolute percentage error (MAPE) and mean square error (MSE), were used to compare the performance among the three models. RESULTS: The morbidity of hepatitis from Jan 2005 to Dec 2012 has seasonal variation and slightly rising trend. The ARIMA(0,1,2)(1,1,1)12 model was the most appropriate one with the residual test showing a white noise sequence. The smoothing factor of the basic GRNN model and the combined model was 1.8 and 0.07, respectively. The four parameters of the hybrid model were lower than those of the two single models in the validation. The parameters values of the GRNN model were the lowest in the fitting of the three models. CONCLUSIONS: The hybrid ARIMA-GRNN model showed better hepatitis incidence forecasting in Heng County than the single ARIMA model and the basic GRNN model. It is a potential decision-supportive tool for controlling hepatitis in Heng County.


Assuntos
Hepatite/epidemiologia , Modelos Teóricos , China/epidemiologia , Humanos , Incidência , Saúde Pública
19.
J Nanosci Nanotechnol ; 14(10): 7879-83, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25942885

RESUMO

Amorphous binary Ti(100-x)Cu(x) (x = 40, 50 and 60 at%) alloys, as the starting materials, were dealloyed in 0.03 and 0.13 M HF solutions under a free immersion condition, and a uniform nanoporous structure with a pore size of 71-220 nm and ligament size of 72-209 nm was obtained after immersion for 43.2 ks. The evolution of nanoporosity underwent more uniformly due to the absence of the intermetallics and defects such as grain boundary, segregation in the chemical composition in the amorphous precursors. The pore size and the ligament size increased with the immersion times and the concentration of the treatment solutions. The pore size increased with the dealloying times exponentially with an exponent of 0.41-0.79. The evolution of nanoporosity was influenced by the alloy compositions, and the formation of the ligaments was controlled by surface diffusion of the Cu adatoms, and also influenced by the coverage of noble Cu contents in Ti-Cu alloys.

20.
J Hazard Mater ; 262: 589-97, 2013 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-24095999

RESUMO

Hybrid nanomaterials comprising phosphotungstic acid (PTA) and MIL-101(Cr) were prepared through one-pot synthesis and post-modification methods and then were used as adsorbents of dibenzothiophene (DBT) from simulated diesel fuels. Samples obtained by different ways (encapsulation and impregnation) were characterized by nitrogen adsorption, transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR) and series of adsorption experiments. The equilibrium adsorption capacities of PTA@MIL-101(Cr) illustrated that the direct introduction of PTA into MIL-101(Cr) during synthesis resulted in a 10.7% increase compared with MIL-101(Cr). However, porous hybrid adsorbent PTA/MIL-101(Cr) prepared via post-modification method exhibited lower adsorption capacity than virgin MIL-101(Cr). The theoretical maximum adsorption capacity (Q0) of PTA@MIL-101(Cr) is 136.5mg S/g adsorbent, 4.2 times of MIL-101(Cr). Even in competitive adsorption between aromatic compounds, which possess strong affinity with MOFs, and DBT, PTA@MIL-101(Cr) and MIL-101(Cr) remained their effectiveness in removal of DBT in the system. Based on these results, it can be presumed that MIL-101(Cr), modified properly, can be used as a promising adsorbent for eliminating aromatics and S-compounds in commercial fuels simultaneously.


Assuntos
Poluentes Atmosféricos/química , Cromo/química , Complexos de Coordenação/química , Nanoestruturas/química , Ácido Fosfotúngstico/química , Tiofenos/química , Adsorção , Poluição do Ar/prevenção & controle , Gasolina , Estruturas Metalorgânicas
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