Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Zhonghua Yi Xue Za Zhi ; 102(1): 73-79, 2022 Jan 04.
Artigo em Chinês | MEDLINE | ID: mdl-34991241

RESUMO

Objective: To clarify the effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) on cognitive function in cerebral ischemic rats, and to explore its underlying mechanism by RNA sequencing. Methods: Thirty male Sprague-Dawley (SD) rats underwent transient middle cerebral artery occlusion (tMCAO). According to the Bederson score, 10 rats with a score of 1-3 were excluded, and the remaining 20 rats were then randomly divided into the tMCAO group (n=10) and the rTMS group (n=10). Meanwhile, 10 rats with sham operation were assigned to the sham group (n=10). Rats in the rTMS group received 20 Hz rTMS from day 7 to day 28 after surgery. From day 28 to day 33 after the operation, Morris water maze test was performed to detect the cognitive function of rats in each group. The cortical tissues around the infarcts from the rTMS tMCAO groups were taken for RNA sequencing analysis, with 3 rats in each group. Results: The escape latency of rats in the rTMS group[ (53±4)s] and the group [(51±5)s] were significantly shorter than that of the tMCAO group[ (58±4)s, P<0.05)]. The times that the rats crossed the original platform in 60 seconds in the rTMS group[2.5 (1.5-3.0)] and sham group[3.0 (1.5-3.0)] were more than that of the tMCAO group [1.0(0.5-1.5)] (P<0.05). RNA sequencing detected 16 significantly differentially expressed genes, including 9 up-regulated genes and 7 down-regulated genes. GO analysis showed that the functions of up-regulated genes were mainly concentrated in the processes of chemical homeostasis and cell metal ion homeostasis. While the functions of down-regulated genes mainly enriched in the inflammatory response. Conclusion: Twenty Hz rTMS can improve the cognitive function of rats with cerebral infarction, and its underlying mechanism may be related to maintaining chemical and metal ion homeostasis and regulating the polarization of microglia to reduce neuroinflammation.


Assuntos
Estimulação Magnética Transcraniana , Animais , Cognição , Masculino , Ratos , Ratos Sprague-Dawley , Análise de Sequência de RNA
2.
Phys Rev Lett ; 127(3): 031102, 2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34328784

RESUMO

We report observations of gamma-ray emissions with energies in the 100-TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their positional coincidences, we associate one with a pulsar PSR J2032+4127 and the other mainly with a pulsar wind nebula PWN G75.2+0.1, with the pulsar moving away from its original birthplace situated around the centroid of the observed gamma-ray emission. This work would stimulate further studies of particle acceleration mechanisms at these gamma-ray sources.

3.
Phys Rev Lett ; 126(14): 141101, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33891464

RESUMO

We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources and compatible with expectations from the hadronic emission scenario in which gamma rays originate from the decay of π^{0}'s produced through the interaction of protons with the interstellar medium in the Galaxy. This is strong evidence that cosmic rays are accelerated beyond PeV energies in our Galaxy and spread over the Galactic disk.

4.
Phys Rev Lett ; 123(5): 051101, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31491288

RESUMO

We report on the highest energy photons from the Crab Nebula observed by the Tibet air shower array with the underground water-Cherenkov-type muon detector array. Based on the criterion of a muon number measured in an air shower, we successfully suppress 99.92% of the cosmic-ray background events with energies E>100 TeV. As a result, we observed 24 photonlike events with E>100 TeV against 5.5 background events, which corresponds to a 5.6σ statistical significance. This is the first detection of photons with E>100 TeV from an astrophysical source.

5.
Phys Rev Lett ; 120(3): 031101, 2018 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-29400499

RESUMO

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disk center in the "away" ("toward") interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54±0.21_{stat}±0.20_{syst} (1.62±0.15_{stat}±0.22_{syst}) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.

6.
Phys Rev Lett ; 111(1): 011101, 2013 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-24027782

RESUMO

We report on a clear solar-cycle variation of the Sun's shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun's shadow, using the potential field source surface model and the current sheet source surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun's shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun's shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun's shadow observed in the TeV cosmic-ray flux.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...