Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Assunto da revista
País de afiliação
Intervalo de ano de publicação
1.
Sci Rep ; 13(1): 21379, 2023 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-38049489

RESUMO

African desert dust is emitted and long-range transported with multiple effects on climate, air quality, cryosphere, and ecosystems. On 21-23 February 2021, dust from a sand and dust storm in northern Africa was transported to Finland, north of 60°N. The episode was predicted 5 days in advance by the global operational SILAM forecast, and its key features were confirmed and detailed by a retrospective analysis. The scavenging of dust by snowfall and freezing rain in Finland resulted in a rare case of substantial mineral dust contamination of snow surfaces over a large area in the southern part of the country. A citizen science campaign was set up to collect contaminated snow samples prepared according to the scientists' instructions. The campaign gained wide national interest in television, radio, newspapers and social media, and dust samples were received from 525 locations in Finland, up to 64.3°N. The samples were utilised in investigating the ability of an atmospheric dispersion model to simulate the dust episode. The analysis confirmed that dust came from a wide Sahara and Sahel area from 5000 km away. Our results reveal the features of this rare event and demonstrate how deposition samples can be used to evaluate the skills and limitations of current atmospheric models in simulating transport of African dust towards northern Europe.

2.
Sci Rep ; 12(1): 5597, 2022 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-35379883

RESUMO

The aridification of Central Asia since the Eocene has widespread evidence, but climate-controlled environmental reorganizations during the Oligocene remain ambiguous. We employed environmental magnetic, mineralogical and geochemical methods on a latest Eocene to late Oligocene terrestrial sequence in Inner Mongolia, China, to examine how global climatic trends and regional factors influenced the evolution of moisture and weathering in the region. Highlighting the climatic influence, our weathering and rainfall proxy data document the drawdown of atmospheric CO2 and global cooling during the early Oligocene semi-arid phase, which culminated in the Early Oligocene Aridification Event at 31 Ma. Moreover, for the first time in the terrestrial eastern Central Asian setting, we provide geochemical and geophysical evidence for a second major Oligocene aridification event nearly synchronous to the mid-Oligocene Glacial Maximum at around 28 Ma. These aridification events were interrupted by periods of increased rainfall and weathering and can be associated with the terminations of glacial events seen in marine oxygen isotope records.


Assuntos
Poeira , China
3.
Front Med (Lausanne) ; 6: 123, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31245375

RESUMO

Magnetic iron oxide nanoparticles, magnetite/maghemite, have been identified in human tissues, including the brain, meninges, heart, liver, and spleen. As these nanoparticles may play a role in the pathogenesis of neurodegenerative diseases, a pilot study explored the occurrence of these particles in the cervical (neck) skin of 10 patients with Parkinson's disease and 10 healthy controls. Magnetometry and transmission electron microscopy analyses revealed magnetite/maghemite nanoparticles in the skin samples of every study participant. Regarding magnetite/maghemite concentrations of the single-domain particles, no significant between-group difference was emerged. In low-temperature magnetic measurement, a magnetic anomaly at ~50 K was evident mainly in the dermal samples of the Parkinson group. This anomaly was larger than the effect related to the magnetic ordering of molecular oxygen. The temperature range of the anomaly, and the size-range of magnetite/maghemite, both refute the idea of magnetic ordering of any iron phase other than magnetite. We propose that the explanation for the finding is interaction between clusters of superparamagnetic and single-domain-sized nanoparticles. The source and significance of these particles remains speculative.

4.
Anticancer Res ; 36(5): 2297-306, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27127136

RESUMO

BACKGROUND/AIM: Harmans are condensation products of acetaldehyde and biogenic amines in saliva. Like other monoamine oxidase inhibitors, harmans help maintain behavioral sensitization to nicotine and mediate the addictive potential of cigarette smoke-derived acetaldehyde. The aim of this study was to test the hypothesis that effective elimination of acetaldehyde in saliva by slow-release L-cysteine (Acetium™ lozenge; Biohit Oyj, Helsinki, Finland) blocks the formation of harmans and eliminates acetaldehyde-enhanced nicotine addiction in smokers. STUDY DESIGN: A double-blind, randomized, placebo-controlled trial comparing Acetium lozenges and placebo in smoking intervention was undertaken. MATERIALS AND METHODS: A cohort of 423 cigarette smokers were randomly allocated to intervention (n=212) and placebo arms (n=211). Smoking-related data were recorded by questionnaires, together with nicotine dependence testing by Fagerström scale. The participants used a smoking diary to record the daily number of cigarettes, test lozenges and sensations of smoking. The data were analyzed separately for point prevalence of abstinence and prolonged abstinence endpoints. RESULTS: Altogether, 110 study participants completed the trial per protocol, 234 had minor violations, and the rest (n=79) were lost to follow-up. During the 6-month trial, 65 participants quit smoking; 38 (17.9%) in the intervention arm and 27 (12.8%) in the placebo arm [odds ratio (OR)=1.48; 95% confidence intervals (CI)=0.87-2.54; p=0.143]. Success in the per protocol group was better (42.9% vs. 31.1%, respectively; OR=1.65, 95% CI=0.75-3.62; p=0.205) than in the modified intention-to-treat group: 13.5% vs. 7.4% (p=0.128). CONCLUSION: If the efficacy of Acetium lozenge can be confirmed in an adequately powered study, this new approach would represent a major breakthrough in smoking quit intervention because slow-release L-cysteine is non-toxic with no side-effects or limitations of use.


Assuntos
Acetaldeído/análise , Cisteína/administração & dosagem , Saliva/química , Fumaça , Produtos do Tabaco , Dispositivos para o Abandono do Uso de Tabaco , Administração Oral , Adulto , Testes Respiratórios , Monóxido de Carbono/análise , Preparações de Ação Retardada , Método Duplo-Cego , Feminino , Seguimentos , Harmina/análogos & derivados , Harmina/biossíntese , Humanos , Masculino , Prontuários Médicos , Pessoa de Meia-Idade , Abandono do Hábito de Fumar , Inquéritos e Questionários , Resultado do Tratamento
5.
J Med Chem ; 48(13): 4231-6, 2005 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-15974576

RESUMO

Novel 1-R-imidazole-2-nitrolic acids and 1-R-imidazole-5-nitrolic acids (R: H, Me, Bn) were synthesized from oximes by treatment with a mixture of fuming nitric acid and acetic acid. The effects of these potential nitric oxide-donating compounds were tested on ocular variables such as intraocular pressure and formation of cyclic guanosine-3,5'-monophosphate in the incubation of porcine iris-ciliary body.


Assuntos
Humor Aquoso/fisiologia , Imidazóis/síntese química , Imidazóis/farmacologia , Nitroglicerina/síntese química , Nitroglicerina/farmacologia , Animais , Humor Aquoso/efeitos dos fármacos , GMP Cíclico/metabolismo , Desenho de Fármacos , Iris/efeitos dos fármacos , Iris/fisiologia , Modelos Moleculares , Estrutura Molecular , Nitratos/metabolismo , Nitritos/metabolismo , Suínos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA