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1.
J Am Chem Soc ; 145(12): 6927-6943, 2023 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-36942998

RESUMO

Electrochemical partial oxidation of methane to methanol is a promising approach to the transformation of stranded methane resources into a high-value, easy-to-transport fuel or chemical. Transition metal oxides are potential electrocatalysts for this transformation. However, a comprehensive and systematic study of the dependence of methane activation rates and methanol selectivity on catalyst morphology and experimental operating parameters has not been realized. Here, we describe an electrochemical method for the deposition of a family of thin-film transition metal (oxy)hydroxides as catalysts for the partial oxidation of methane. CoOx, NiOx, MnOx, and CuOx are discovered to be active for the partial oxidation of methane to methanol. Taking CoOx as a prototypical methane partial oxidation electrocatalyst, we systematically study the dependence of activity and methanol selectivity on catalyst film thickness, overpotential, temperature, and electrochemical cell hydrodynamics. Optimal conditions of low catalyst film thickness, intermediate overpotentials, intermediate temperatures, and fast methanol transport are identified to favor methanol selectivity. Through a combination of control experiments and DFT calculations, we show that the oxidized form of the as-deposited (oxy)hydroxide catalyst films are active for the thermal oxidation of methane to methanol even without the application of bias potential, demonstrating that high valence transition metal oxides are intrinsically active for the activation and oxidation of methane to methanol at ambient temperatures. Calculations uncover that electrocatalytic oxidation enables reaching an optimum potential window in which methane activation forming methanol and methanol desorption are both thermodynamically favorable, methanol desorption being favored by competitive adsorption with hydroxide anion.

2.
AIDS Care ; 28(7): 927-31, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26754350

RESUMO

It has become popular for men who have sex with men (MSM) to use mobile-phone geosocial networking applications (mobile apps) to find sex partners. A cross-sectional online survey was conducted in Taiwan to compare the sexual and substance-use behaviors of MSM seeking sex partners through the internet and mobile apps. Of the 1060 participants, 65.8% used the internet via computer and 37.7% used a mobile app to find sexual partners, while 30.3% used recreational drugs or alcohol in the previous 6 months. MSM who exclusively used mobile apps to seek sex partners were significantly more likely than MSM seeking sex via computer to be older, to have used recreational drugs or alcohol, and to have sex with HIV-positive partners. Additionally, using mobile apps to seek sex partners was significantly associated with having sex with online partners through either mobile apps or computer-based internet use (adjusted odds ratio (AOR), 7.12 [3.87-13.11]), self-reporting as HIV-positive (AOR, 2.24 [1.12-4.12]), using recreational drugs (AOR, 1.67 [1.21-2.32]), having disclosed HIV status to sexual partners (AOR, 1.44 [1.03-2.02]), and having sex with HIV-positive partners (AOR, 1.81 [1.06-3.10]). In conclusion, the mobile apps may serve as a feasible platform for HIV-positive MSM to find other HIV-positive partners.


Assuntos
Telefone Celular/estatística & dados numéricos , Computadores/estatística & dados numéricos , Infecções por HIV , Homossexualidade Masculina , Adulto , Fatores Etários , Estudos Transversais , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Infecções por HIV/psicologia , Soropositividade para HIV/epidemiologia , Soropositividade para HIV/psicologia , Seleção por Sorologia para HIV/psicologia , Seleção por Sorologia para HIV/estatística & dados numéricos , Homossexualidade Masculina/psicologia , Homossexualidade Masculina/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Aplicativos Móveis , Assunção de Riscos , Parceiros Sexuais/psicologia , Taiwan/epidemiologia
3.
Hu Li Za Zhi ; 63(3): 25-30, 2016 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-27250956

RESUMO

Adhering to ethics protocols has become increasingly important in the process of doing research in Taiwan since the introduction of research-ethics mechanisms. Adhering to these protocols affects research on Taiwan's indigenous peoples due to the vulnerability of indigenous groups and to their increasing rights consciousness. The present paper explains the context of group rights from a national self-determination perspective and then discusses the current indigenous research-ethics mechanisms in Taiwan. The ethical guidelines for indigenous research in Canada, TCPS2 2014-Tri-Council Policy Statement: Ethical Conduct for Research Involving Humans are referenced as a model for protocols that may foster positive and mutually trusting relationships between academic researchers and indigenous communities in Taiwan.


Assuntos
Ética em Pesquisa , Grupos Populacionais , Humanos , Autonomia Pessoal , Taiwan
4.
J Am Soc Mass Spectrom ; 33(10): 1891-1903, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36111786

RESUMO

Collision-induced dissociation (CID) tandem mass spectrometry is commonly used for carbohydrate structural determinations. In the CID tandem mass spectrometry approach, carbohydrates are dissociated into fragments, and this is followed by the structural identification of fragments through subsequent CID. The success of the structural analysis depends on the structural correlation of fragments before and after dissociation, that is, structural memory of fragments. Fragments that completely lose the memory of their original structures cannot be used for structural analysis. By contrast, fragments with extremely strong correlations between the structures before and after fragmentation retain the information on their original structures as well as have memories of their precursors' entire structures. The CID spectra of these fragments depend on their own structures and on the remaining parts of the precursor structures, making structural analysis impractical. For effective structural analysis, the fragments produced from a precursor must have good structural memory, meaning that the structures of these fragments retain their original structure, and they must not be strongly affected by the remaining parts of the precursors. In this study, we found that most of the carbohydrate fragments produced by low-energy CID have good memory in terms of linkage position and anomericity. Fragments with ugly memory, where fragment structures change with the remaining parts of the precursors, can be attributed to C ion formation in a linear form. Fragments with ugly memory can be changed to have good memory by preventing linear C ion generation by using an alternative CID sequence, or the fragments of ugly memory can become useful in structural analysis when the contribution of linear C ions in fragmentation patterns is understood.


Assuntos
Carboidratos , Espectrometria de Massas em Tandem , Íons/química , Espectrometria de Massas em Tandem/métodos
5.
AIDS Educ Prev ; 28(6): 539-556, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27925489

RESUMO

With the rapid proliferation and adoption of social media among healthcare professionals and organizations, social media-based HIV/AIDS intervention programs have become increasingly popular. However, the question of the effectiveness of the HIV/AIDS messages disseminated on social media has received scant attention in the literature. The current study applies content analysis to examine the relationship between Facebook messaging strategies employed by 110 HIV/AIDS nonprofit organizations and audience reactions in the form of liking, commenting, and sharing behavior. The results reveal that HIV/AIDS nonprofit organizations often use informational messages as one-way communication with their audience instead of dialogic interactions. Some specific types of messages, such as medication-focused messages, engender better audience engagement; in contrast, event-related messages and call-to-action messages appear to translate into lower corresponding audience reactions. The findings provide guidance to HIV/AIDS organizations in developing effective social media communication strategies.


Assuntos
Comunicação , Infecções por HIV/prevenção & controle , Comunicação em Saúde/métodos , Organizações sem Fins Lucrativos , Mídias Sociais , Rede Social , Síndrome da Imunodeficiência Adquirida , Infecções por HIV/psicologia , Humanos
6.
Chem Asian J ; 9(9): 2444-8, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25044373

RESUMO

The pyrrolidine-camphorsulfonamide-based catalyst 1 a catalyzes the enantioselective conjugate addition of nitroalkanes to α,ß-unsaturated aldehydes in the presence of five equivalents of water in iPrOH to give the corresponding chiral Michael adducts in good yields and high enantioselectivities (up to 99% ee) with a catalyst loading as low as 1 mol%.

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