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1.
JAMA ; 324(18): 1844-1854, 2020 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-33170240

RESUMO

Importance: Electronic cigarettes (e-cigarettes) for smoking cessation remain controversial. Objective: To evaluate e-cigarettes with individual counseling for smoking cessation. Design, Setting, and Participants: A randomized clinical trial enrolled adults motivated to quit smoking from November 2016 to September 2019 at 17 Canadian sites (801 individuals screened; 274 ineligible and 151 declined). Manufacturing delays resulted in early termination (376/486 participants, 77% of target). Outcomes through 24 weeks (March 2020) are reported. Interventions: Randomization to nicotine e-cigarettes (n = 128), nonnicotine e-cigarettes (n = 127), or no e-cigarettes (n = 121) for 12 weeks. All groups received individual counseling. Main Outcomes and Measures: The primary end point was point prevalence abstinence (7-day recall, biochemically validated using expired carbon monoxide) at 12 weeks, changed from 52 weeks following early termination. Participants missing data were assumed to be smoking. The 7 secondary end points, examined at multiple follow-ups, were point prevalence abstinence at other follow-ups, continuous abstinence, daily cigarette consumption change, serious adverse events, adverse events, dropouts due to adverse effects, and treatment adherence. Results: Among 376 randomized participants (mean age, 52 years; 178 women [47%]), 299 (80%) and 278 (74%) self-reported smoking status at 12 and 24 weeks, respectively. Point prevalence abstinence was significantly greater for nicotine e-cigarettes plus counseling vs counseling alone at 12 weeks (21.9% vs 9.1%; risk difference [RD], 12.8 [95% CI, 4.0 to 21.6]) but not 24 weeks (17.2% vs 9.9%; RD, 7.3 [95% CI, -1.2 to 15.7]). Point prevalence abstinence for nonnicotine e-cigarettes plus counseling was not significantly different from counseling alone at 12 weeks (17.3% vs 9.1%; RD, 8.2 [95% CI, -0.1 to 16.6]), but was significantly greater at 24 weeks (20.5% vs 9.9%; RD, 10.6 [95% CI, 1.8 to 19.4]). Adverse events were common (nicotine e-cigarette with counseling: 120 [94%]; nonnicotine e-cigarette with counseling: 118 [93%]; counseling only: 88 [73%]), with the most common being cough (64%) and dry mouth (53%). Conclusions and Relevance: Among adults motivated to quit smoking, nicotine e-cigarettes plus counseling vs counseling alone significantly increased point prevalence abstinence at 12 weeks. However, the difference was no longer significant at 24 weeks, and trial interpretation is limited by early termination and inconsistent findings for nicotine and nonnicotine e-cigarettes, suggesting further research is needed. Trial Registration: ClinicalTrials.gov Identifier: NCT02417467.


Assuntos
Aconselhamento , Sistemas Eletrônicos de Liberação de Nicotina , Abandono do Hábito de Fumar/métodos , Redução do Consumo de Tabaco/estatística & dados numéricos , Tabagismo/terapia , Adulto , Terapia Combinada , Término Precoce de Ensaios Clínicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Autorrelato , Dispositivos para o Abandono do Uso de Tabaco
2.
Philos Trans A Math Phys Eng Sci ; 360(1790): 61-88, 2002 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-16210171

RESUMO

The slow (diffusion-limited) oxidation of metal nanoparticles has previously been proposed as the mechanism for ball lightning energy release, and argued to be the result of a normal lightning strike on soil. Here this basic model of networked nanoparticles is detailed further, and extended to lightning strikes on metal structures, and also to the action of other storm-related discharges or man-made discharges. The basic model predicted the important properties of "average" observed ball lightning, and the extension in this paper also covers high-energy examples of ball lightning. Laboratory checks of the theory are described, and predictions given of what conditions are necessary for observing ball lightning in the laboratory. Key requirements of the model are a sheltered region near the strike foot and starting materials which can generate a metal vapour under intensive heating, including soil, wood or a metal structure. The evolution of hydrocarbons (often plastics) along with metal vapour can ensure the local survival of the metal vapour even in an oxidizing atmosphere. Subsequent condensation of this vapour to metallic nanoparticles in networks provides the coherence of a ball structure, which also releases light over an extended time. Also discussed is the passage of ball lightning through a sheet of building material, including glass, and its occasional charring of flesh on close contact.


Assuntos
Atmosfera , Raio , Metais/química , Modelos Químicos , Nanoestruturas/química , Solo , Madeira , Microscopia Eletrônica de Varredura , Oxirredução
3.
Philos Trans A Math Phys Eng Sci ; 360(1790): 11-35, 2002 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-16210169

RESUMO

The observations in the first section of this paper were sent to John Abrahamson in response to the publication of a recent paper on ball lightning, with the correspondents either reading the original paper, or reports of it in popular science articles. A selection of the cases has been made, including those which showed interesting detail possibly useful in debating ball lightning mechanisms. Any inserted text within parenthesis is the observer's response to follow-up queries from J.A. The age of the observer (where noted) is that at the time of the observation. Three observations (1 q-s) did not show motion independent of their surroundings, but have been included because of their other similarities to ball lightning. It is interesting to note the high proportion (greater than 0.5) of scientifically or technically trained observers in this collection. The data presented in the second section of this paper come from both letters and interviews. Our interview questionnaire consisted of 46 questions and was mostly carried out in quiet conditions. Observations in 2 a, e, h, l, m, q-t were corrected during several (two or three) interviews. Heading each observation case we note the most unusual property of the object. Ball lightning appears in Russia and the Ukraine usually in summer (June-August), and more rarely in spring (March-May), or autumn (September-November). It appears usually during the daytime, 13:00-17:00 h, when most summer thunderstorms take place. Observers in their descriptions usually use the term "morning" to describe the period from 06:00 to 11:00 h, "daytime" for 12:00-18:00 h, and "evening" for 19:00-21:00 h. The term "time' means the local time, and sometimes it is difficult to compare it with the local geographic time due to frequent official state summer-winter time changes. The decree time in Russia can in general differ from the geographic time by 1-2 h.


Assuntos
Raio , Feminino , Humanos , Entrevistas como Assunto , Masculino , Federação Russa , Inquéritos e Questionários , Ucrânia
4.
Philos Trans A Math Phys Eng Sci ; 360(1790): 97-106, 2002 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-16210173

RESUMO

A compilation of 17 observations of ball lightning showing the most energetic effects is presented along with estimates of their energy content. These observations were chosen from several thousand for the much stronger interaction of each ball lightning on its surroundings, and the method of energy estimation outlined. The case is put that some of the observations show a higher energy than self-contained chemical energy could provide. Comments have been added to the paper, arguing that the energy estimations themselves should be consistent with whatever model is used for ball lightning. For example, the presence of reacting nanoparticles releasing chemical energy may bring about the same observed effects with lower estimated energy.


Assuntos
Eletroquímica , Raio , Modelos Químicos
5.
Philos Trans A Math Phys Eng Sci ; 360(1790): 3, 2002 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-16210167

Assuntos
Raio
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