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1.
Acta Orthop Belg ; 88(4): 661-665, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36800648

RESUMO

There were 3 major anesthesia methods for discectomy: local, epidural and general. A lot of studies has been established to compare these three methods in different aspects, however, the result is still controversial. We conducted this network meta-analysis to evaluate these methods. Electronic databases including PubMed, EMBASE, Cochrane Library, were searched to identify clinical trials that reported the effects of local anesthesia general anesthesia and epidural anesthesia in lumbar disc herniation. Three indicators were included for evaluation: post-operative VAS score, complication, operation duration. In total, 12 studies and 2287 patients were included for this study. For complication, epidural anesthesia shows significantly lower rate compare to general anesthesia (OR: 0.45, 95% CI [0.24, 0.45], P=0.015), but local anesthesia didn't show significant result, no significant heterogeneity was observed between designs. For VAS score, epidural anesthesia showed a better effect (MD: -1.61, 95%CI [-2.24, -0.98]) compare to general anesthesia, and local anesthesia has a similar effect (MD: -0.91, 95%CI [-1.54, -0.27]). However this result showed a very high heterogeneity (I2=95%). For operation duration, local anesthesia showed a significant lesser time compare to general anesthesia (MD: -46.31(minutes), 95%CI [-73.73, -19.19]) but epidural anesthesia didn't have one, this result also showed a very high heterogeneity (I2=98%). Epidural anesthesia showed lesser post- operative complication compare to general anesthesia in lumbar disc herniation surgery.


Assuntos
Anestesia Epidural , Deslocamento do Disco Intervertebral , Humanos , Deslocamento do Disco Intervertebral/cirurgia , Anestesia Local , Metanálise em Rede , Anestesia Epidural/efeitos adversos , Anestesia Epidural/métodos , Complicações Pós-Operatórias , Anestesia Geral/efeitos adversos , Vértebras Lombares/cirurgia , Resultado do Tratamento
2.
Eur Spine J ; 29(5): 1147-1158, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32200495

RESUMO

PURPOSE: To evaluate the safety and efficacy of a system aiming to correct scoliosis called "electromagnetically controlled shape-memory alloy rods" (EC-SMAR) used in a rabbit model. METHODS: We heat-treated shape-memory alloy (SMA) rods to achieve a transition temperature between 34 and 47 °C and a C-shape austenite phase. We then developed a water-cooled generator capable of generating an alternating magnetic field (100 kHz) for induction heating. We next studied the efficacy of this system in vitro and determined some parameters prior to proceeding with animal experiments. We then employed a rabbit model, in which we fixed a straight rod along the spinous processes intraoperatively, and conducted induction heating postoperatively every 4 days for 1 month, while performing periodic X-ray assessments. RESULTS: Significant kyphotic deformations with Cobb angles of about 45° (p < 0.01) were created in five rabbits, and no complications occurred throughout the experiment. The rabbits are still very much alive and do not show any signs of discomfort. CONCLUSIONS: This is the first system that can modulate spinal deformation in a gradual, contactless, noninvasive manner through electromagnetic induction heating applied to SMA alloy rods. Although this study dealt with healthy spines, it provides promising evidence that this device also has the capacity to correct human kyphosis and even scoliosis in the future. These slides can be retrieved under Electronic Supplementary Material.


Assuntos
Escoliose , Ligas de Memória da Forma , Ligas , Animais , Níquel , Coelhos , Escoliose/cirurgia , Coluna Vertebral , Titânio
3.
Sensors (Basel) ; 20(9)2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32392724

RESUMO

This paper describes a novel sounding system for which the functions of the medium frequency (MF) radar and the ionosonde are integrated on the same hardware platform and antenna structure, namely the middle atmosphere-ionosphere (MAI) system. Unlike the common MF radar, MAI system adopts the pseudo-random (PRN) phase-coded modulation technology, which breaks the limitation of the traditional monopulse mode. Through the pulse compression, only a small peak power is needed to achieve the signal-to-noise ratio (SNR) requirement. The excellent anti-jamming performance is also very suitable for the ionospheric sounding. One transmitting and six receiving modes are adopted for the MF sounding. While neglecting the structure of the T/R switches, the coupling interference between the transmitter and the receiver may also be avoided. Moreover, by employing a miniaturized antenna array composed of progressive-wave antennas for the MF receiving and ionospheric sounding, the MAI system takes account of the requirements of the inversion algorithms of MF radar and the large bandwidth need for the ionospheric sounding concurrently. Such an antenna structure can also greatly simplify the system structure and minimize the difficulty of deployment. The experiments verified the availability of the system scheme and its engineering application significance. Through further analysis of the sounding data, the wind field of the mesosphere, the electron density of D layer and electron density profile from layers E to F were obtained at the identical location. The capability of MAI system can play an important role in studying the interaction and coupling mechanism between the mesosphere and ionosphere.

4.
Sensors (Basel) ; 19(4)2019 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-30769811

RESUMO

In this paper, complete complementary code (CCC) sequences are applied to a High Frequency (HF) ionospheric sounding network. Ionosondes distributed at multiple locations use the mutually orthogonal CCC sequences to conduct vertical soundings synchronously. At the same time, thanks to the omnidirectional antennas, every station can receive the oblique echoes transmitted from the others. Due to the orthogonality between the code sequences, both vertical and oblique ionograms can be simultaneously obtained and completely separated. Through this method, the sounding efficiency can be enhanced, and the inversion difficulty can be reduced. Further, by using the data assimilation method, vertical and oblique sounding results can be combined to obtain a wide range of regional ionospheric characteristics. To verify the performance of this kind of sounding network, validation experiments are implemented to demonstrate that vertical and oblique ionograms can be obtained independently at the same time and inverted separately and that the maps of foF2 parameters obtained by using the data assimilation method provide more details than single vertical or oblique sounding.

5.
Nature ; 467(7318): 943-6, 2010 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-20962841

RESUMO

Earth's diffuse aurora occurs over a broad latitude range and is primarily caused by the precipitation of low-energy (0.1-30-keV) electrons originating in the central plasma sheet, which is the source region for hot electrons in the nightside outer magnetosphere. Although generally not visible, the diffuse auroral precipitation provides the main source of energy for the high-latitude nightside upper atmosphere, leading to enhanced ionization and chemical changes. Previous theoretical studies have indicated that two distinct classes of magnetospheric plasma wave, electrostatic electron cyclotron harmonic waves and whistler-mode chorus waves, could be responsible for the electron scattering that leads to diffuse auroral precipitation, but it has hitherto not been possible to determine which is the more important. Here we report an analysis of satellite wave data and Fokker-Planck diffusion calculations which reveals that scattering by chorus is the dominant cause of the most intense diffuse auroral precipitation. This resolves a long-standing controversy. Furthermore, scattering by chorus can remove most electrons as they drift around Earth's magnetosphere, leading to the development of observed pancake distributions, and can account for the global morphology of the diffuse aurora.

6.
Cell Physiol Biochem ; 34(4): 1175-89, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25277442

RESUMO

BACKGROUND/AIMS: Apoptosis and autophagy are two patterns of programmed cell death which play important roles in the intervertebral disc degeneration. Oxidative stress is an important factor for the induction of programmed cell death. However, the cellular reactions linking autophagy to apoptosis of disc cells under oxidative stress have never been described. This study investigated the responses of autophagy and apoptosis and their interactions in the nucleus pulposus cells (NP cells) under oxidative stress, with the aim to better understand the mechanism of disc degeneration. METHODS: NP cells isolated from rat lumbar discs were subjected to different concentrations of H2O2 for various time periods. Cell viability was determined by CCK-8 assay, and their apoptosis and autophagy responses were evaluated by fluorescent analysis, flow cytometry and western blotting, et al. The interactions of autophagy and apoptosis and the possible signaling pathways were also investigated by using autophagy modulators. RESULTS: H2O2 increased the lysosomal membrane permeability in the NP cells and induced apoptosis through the mitochondrial pathway subsequently. Meanwhile, H2O2 stimulated an early autophagy response through the ERK/m-TOR signaling pathway. Autophagy inhibition significantly decreased the apoptosis incidence in the cells insulted by H2O2. CONCLUSION: These results suggested that controlling the autophagy response in the NP cells under oxidative stress should be beneficial for the survival of the cells and probably delay the process of disc degeneration.


Assuntos
Apoptose/fisiologia , Autofagia/fisiologia , Degeneração do Disco Intervertebral/patologia , Disco Intervertebral/patologia , Estresse Oxidativo/fisiologia , Animais , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Permeabilidade da Membrana Celular/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Peróxido de Hidrogênio/farmacologia , Disco Intervertebral/efeitos dos fármacos , Disco Intervertebral/metabolismo , Degeneração do Disco Intervertebral/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Serina-Treonina Quinases TOR/metabolismo
7.
Cytokine ; 70(2): 87-96, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25127907

RESUMO

Autophagy and apoptosis are important in maintaining the metabolic homeostasis of intervertebral disc cells, and transforming growth factor-ß1 (TGF-ß1) is able to delay intervertebral disc degeneration. This study determined the effect of TGF-ß1 on the crosstalk between autophagy and apoptosis in the disc cells, with the aim to provide molecular mechanism support for the prevention and treatment of disc degeneration. Annulus fibrosus (AF) cells were isolated and cultured under serum starvation. 10 ng/mL TGF-ß1 reduced the apoptosis incidence in the cells under serum starvation for 48 h, down-regulated the autophagy incidence in the cells pretreated with 3-methyladenine (3-MA) or Bafilomycin A (Baf A), partly rescued the increased apoptosis incidence in the cells pretreated with 3-MA, while further reduced the decreased apoptosis incidence in the cells pretreated with Baf A. Meanwhile, TGF-ß1 down-regulated the expressions of autophagic and apoptotic markers in the cells under starvation, partly down-regulated the expressions of Beclin-1, LC3 II/I and cleaved caspase-3 in the cells pretreated with 3-MA or Baf A, while significantly decreased the expression of Bax/Bcl-2 in the cells pretreated with Baf A. 3-MA blocked the phosphorylation of both AKT and mTOR and partly reduced the inhibitory effect of TGF-ß1 on the expression of LC3 II/I and cleaved caspase-3. TGF-ß1 enhanced the expression of p-ERK1/2 and down-regulated the expressions of LC3 II/I and cleaved caspase-3. U0126 partly reversed this inhibitory effect of TGF-ß1. In conclusion, TGF-ß1 protected against apoptosis of AF cells under starvation through down-regulating excessive autophagy. PI3K-AKT-mTOR and MAPK-ERK1/2 were the possible signaling pathways involved in this process.


Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Disco Intervertebral/citologia , Fator de Crescimento Transformador beta1/farmacologia , Animais , Meios de Cultura Livres de Soro , Citoproteção/efeitos dos fármacos , Imunofluorescência , Disco Intervertebral/efeitos dos fármacos , Disco Intervertebral/ultraestrutura , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Masculino , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fagossomos/efeitos dos fármacos , Fagossomos/ultraestrutura , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo
8.
Artigo em Inglês | MEDLINE | ID: mdl-38461448

RESUMO

This study investigates the efficiency and influence of microneedle parameters, specifically Needle Point Angle (a) and Needle Height (h), on the diffusion of Cannabidiol (CBD) across varying skin depths. Utilizing the Latin Hypercube Sampling method, twelve distinct cases were analyzed. Observations reveal a consistent high concentration of CBD delivered via the microneedle patch, with a notable decrease in concentration as the depth increases, displaying a non-linear trend. Multivariate polynomial regression offers a quantitative relationship between the variables, with the third-order bivariate fitting providing the most accurate representation. Compared to other CBD delivery mechanisms, microneedle patches present enhanced CBD concentrations, circumventing challenges faced by other methods such as dosage inaccuracy, systemic absorption issues, and CBD degradation. The results highlight the potential of microneedle patches as a promising avenue for optimized transdermal drug delivery.

9.
Artigo em Inglês | MEDLINE | ID: mdl-36834467

RESUMO

Artificial intelligence (AI)-enabled text-to-speech transformation has been widely employed to deliver online information in various fields. However, few studies have investigated the effect of the AI voice in environmental risk communication, especially in the field of climate change, an issue that poses a severe threat to global public health. To address this gap, the current study examines how the AI voice impacts the persuasive outcome of climate-related information and the potential mechanism that underlies this process. Based on the social and affect heuristics of voice, we propose a serial mediation model to test the effect of climate-related information delivered by different voice types (AI voice vs. human voice) in eliciting risk perception and motivating pro-environmental behavioral intention. Through an online auditory experiment (N = 397), we found the following. First, the AI voice was as effective as the human voice in eliciting risk perception and motivating pro-environmental behavioral intention. Second, compared with human voice, the AI voice yielded a listener's lower level of perceived identity oneness with the speaker, which decreased risk perception and subsequently inhibited pro-environmental behavioral intention. Third, compared with human voice, the AI voice produced a higher level of auditory fear, which increased risk perception and thereby led to stronger pro-environmental behavioral intention. The paradoxical role of the AI voice and its wise use in environmental risk communication for promoting global public health are discussed.


Assuntos
Percepção da Fala , Voz , Humanos , Intenção , Inteligência Artificial , Fala
10.
Fundam Res ; 3(2): 257-264, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38932924

RESUMO

Among the most intense emissions in the Earth's magnetosphere, electromagnetic ion cyclotron (EMIC) waves are regarded as a critical candidate contributing to the precipitation losses of ring current protons, which however lacks direct multi-point observations to establish the underlying physical connection. Based upon a robust conjunction between the satellite pair of Van Allen Probe B and NOAA-19, we perform a detailed analysis to capture simultaneous enhancements of EMIC waves and ring current proton precipitation. By assuming that the ring current proton precipitation is mainly caused by EMIC wave scattering, we establish a physical model between the wave-driven proton diffusion and the ratio of precipitated-to-trapped proton count rates, which is subsequently applied to infer the intensity of EMIC waves required to cause the observed proton precipitation. Our simulations indicate that the model results of EMIC wave intensity, obtained using either the observed or empirical Gaussian wave frequency spectrum, are consistent with the wave observations, within a factor of 1.5. Our study therefore strongly supports the dominant contribution of EMIC waves to the ring current proton precipitation, and offers a valuable means to construct the global profile of EMIC wave intensity using low-altitude NOAA POES proton measurements, which generally have a broad L-shell coverage and high time resolution in favor of near-real-time conversion of the global EMIC wave distribution.

11.
Front Psychol ; 13: 837820, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35185742

RESUMO

Individuals' unverified information sharing on social media, namely, sharing information without verification, is a major cause of the widespread misinformation amid the COVID-19 pandemic. The association between perceived information overload and unverified information sharing has been well documented in the cognitive overload approach. However, little is known about the underlying mechanism of this process. This study aims to explore the mediating role of anxiety and the moderating role of perceived herd between perceived information overload and unverified information sharing on WeChat. Anxiety demonstrates people's emotional response to the pandemic, whereas perceived herd describes a willingness to share certain information if it has been shared by many. The results of an online survey in China (N = 525) showed that perceived information overload was positively associated with unverified information sharing. In addition, this relationship was partially mediated by anxiety. Moreover, perceived herd positively moderated the link between anxiety and unverified information sharing, such that the indirect effect of perceived information overload on unverified information sharing via anxiety was significant in conditions where the level of perceived herd was high, whereas the indirect effect was not significant in conditions where the level of perceived herd was low. The moderated mediation model extends the cognitive overload approach and indicates that unverified information sharing is not only an individual strategy to cope with information overload but also a herding behavior to manage anxiety. Practical implications for curbing people's tendencies toward unverified information sharing on social media are discussed.

12.
Free Radic Biol Med ; 166: 226-237, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33636337

RESUMO

Oxidative stress plays an important role in the pathogenesis of osteoporosis and impaired bone formation. However, the mechanisms behind which oxidative stress represses bone formation remains unclear. TP53INP2, a target of the tumor suppressor p53, is ubiquitously expressed in various cell types including BMSCs and contributes to autophagosome formation by recruiting ubiquitinated substrates to autophagosomes for degradation. However, little is known about its function in BMSCs and its relation to osteoporosis. In this study, first, we verified that the expression of TP53INP2 was persistently decreased in BMSCs derived from osteoporosis patients and OVX mice, and that the antioxidant N-acetylcysteine could ameliorate this decreased TP53INP2 level in vitro. Second, we identified that the mRNA and protein levels of TP53INP2 decreased in BMSCs under H2O2 induced oxidative stress in a dose-dependent manner, with resultant co-location of LC3 and TP53INP2. Additionally, the autophagy-lysosome system was involved in the degradation process of TP53INP2 and applying autophagy inhibitors (Baf-A1) could significantly increase the TP53INP2 levels in murine and human BMSCs under oxidative stress. Third, gain- and loss-of-function assays revealed that knockdown of TP53INP2 inhibited osteogenic differentiation of BMSCs, while overexpression of TP53INP2 promoted osteogenic differentiation of BMSCs in vitro. Further analysis demonstrated that TP53INP2 promoted osteogenic differentiation of BMSCs by activating Wnt/ß-cantenin signaling. DKK1, an inhibitor of Wnt signaling, resulted in osteogenic defects of BMSCs that had over-expressed TP53INP2. Lithium, a Wnt/ß-catenin activator, improved the mineralization ability in TP53INP2-knockdown BMSCs. Moreover, restoring TP53INP2 levels recovered OVX-derived BMSCs osteogenic differentiation and attenuated bone loss in OVX mice. Taken together, our study indicated that oxidative stress-induced downregulation of TP53INP2 suppressed osteogenic differentiation of BMSCs during osteoporosis and was mediated by the autophagy degradation pathway. These findings may introduce a novel therapeutic target for osteoporosis.


Assuntos
Células-Tronco Mesenquimais , Osteoporose , Animais , Autofagia , Diferenciação Celular , Regulação para Baixo , Humanos , Peróxido de Hidrogênio/toxicidade , Camundongos , Proteínas Nucleares , Osteogênese , Osteoporose/genética , Estresse Oxidativo
13.
Sci Adv ; 7(28)2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34244139

RESUMO

Jupiter's rapidly rotating, strong magnetic field provides a natural laboratory that is key to understanding the dynamics of high-energy plasmas. Spectacular auroral x-ray flares are diagnostic of the most energetic processes governing magnetospheres but seemingly unique to Jupiter. Since their discovery 40 years ago, the processes that produce Jupiter's x-ray flares have remained unknown. Here, we report simultaneous in situ satellite and space-based telescope observations that reveal the processes that produce Jupiter's x-ray flares, showing surprising similarities to terrestrial ion aurora. Planetary-scale electromagnetic waves are observed to modulate electromagnetic ion cyclotron waves, periodically causing heavy ions to precipitate and produce Jupiter's x-ray pulses. Our findings show that ion aurorae share common mechanisms across planetary systems, despite temporal, spatial, and energetic scales varying by orders of magnitude.

14.
Medicine (Baltimore) ; 99(33): e18958, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32871967

RESUMO

We performed this meta-analysis to evaluate the effects of epidural anesthesia and local anesthesia on the surgical outcomes of lumbar disc herniation (DH).Electronic databases including PubMed, EMBASE, Cochrane Library, and the Chinese Academic Journal Full-text Database were searched to identify randomized controlled trials (RCTs) that reported on the effects of local anesthesia and epidural anesthesia in lumbar DH surgical management. Evaluation indicators included: onset time of anesthesia, patient satisfaction, and the rate of adverse effects. There were 6 RCTs with a total of 606 patients in this meta-analysis: 274 cases in the local anesthesia group and 332 in the epidural anesthesia group.This meta-analysis demonstrated that the epidural anesthesia group had a better analgesic effect, a lower adverse effect rate (mean difference [MD] = 0.21, 95% confidence interval [CI] [0.08, 0.54], P = .001) and a better satisfaction rate: (MD = 6.54, 95% CI [2.77, 15.45], P < .0001). The duration of anesthesia was not statistically significant.Epidural anesthesia is a better choice for lumbar DH surgery compared to local anesthesia.


Assuntos
Anestesia Epidural , Anestesia Local , Deslocamento do Disco Intervertebral/tratamento farmacológico , Deslocamento do Disco Intervertebral/cirurgia , Vértebras Lombares/cirurgia , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento
15.
J Int Med Res ; 48(6): 300060520935286, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32588694

RESUMO

OBJECTIVE: To evaluate the feasibility of locked intramedullary nailing, rather than locking plate fixation combined with fibular allograft augmentation, for initial varus proximal humeral fractures. METHODS: This prospective pilot study enrolled patients with initial varus proximal humeral fractures that were treated with a locking intramedullary nail. Radiography was performed to evaluate fracture healing. Data about the visual analogue scale (VAS) pain score, Constant Shoulder Score (CSS), Disabilities of the Arm, Shoulder and Hand (DASH) score, American Shoulder and Elbow Surgeons (ASES) score and shoulder range of motion (ROM) were recorded. RESULTS: Twenty patients, including eight with Neer two-part and 12 with three-part fractures, were followed-up, with a mean time of 12.3 months. All patients sustained fractures that healed without re-varus. During the last follow-up, the shoulder function of the patients had recovered well, with a mean VAS pain score of 1.4, a mean CSS of 83.1, a mean DASH score of 80.8, a mean ASES score of 84.0 and a satisfactory ROM. In one patient, the proximal locking screw came out and was removed via a second surgery. CONCLUSIONS: The use of a locking intramedullary nail alone for initial varus proximal humeral two-/three-part fractures was feasible. This treatment has advantages, such as preventing re-varus and causing milder surgical trauma, than that seen with a locking plate.


Assuntos
Fixação Intramedular de Fraturas , Fraturas do Ombro , Placas Ósseas , Fixação Interna de Fraturas , Humanos , Projetos Piloto , Estudos Prospectivos , Fraturas do Ombro/diagnóstico por imagem , Fraturas do Ombro/cirurgia , Resultado do Tratamento
16.
Nat Commun ; 11(1): 4847, 2020 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973130

RESUMO

Very-Low-Frequency (VLF) transmitters operate worldwide mostly at frequencies of 10-30 kilohertz for submarine communications. While it has been of intense scientific interest and practical importance to understand whether VLF transmitters can affect the natural environment of charged energetic particles, for decades there remained little direct observational evidence that revealed the effects of these VLF transmitters in geospace. Here we report a radially bifurcated electron belt formation at energies of tens of kiloelectron volts (keV) at altitudes of ~0.8-1.5 Earth radii on timescales over 10 days. Using Fokker-Planck diffusion simulations, we provide quantitative evidence that VLF transmitter emissions that leak from the Earth-ionosphere waveguide are primarily responsible for bifurcating the energetic electron belt, which typically exhibits a single-peak radial structure in near-Earth space. Since energetic electrons pose a potential danger to satellite operations, our findings demonstrate the feasibility of mitigation of natural particle radiation environment.

17.
J Orthop Surg Res ; 14(1): 241, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31358027

RESUMO

BACKGROUND: The aim of this study is to explore the effects of TGF-ß1 on autophagy and apoptosis induced by exogenous hydrogen peroxide (H2O2) in annulus fibrosus (AF) cells and possible signal pathways involved in this process. METHODS: AF cells were isolated from rat lumbar discs and subjected to different concentrations of exogenous H2O2 (50, 100, 200 µmol/L) for different time periods (0.5, 1, 2, and 4 h). Cell viability was determined by CCK-8 assay, and the levels of autophagy and apoptosis were evaluated by Western blotting and caspase 3, 8, 9 activity assay. By administration with different concentrations of TGF-ß1 (5, 10, 20 ng/mL), the effects of TGF-ß1 on autophagy and apoptosis induced by H2O2 were observed, and the possible signaling pathways were also investigated by using various apoptosis inhibitors or an autophagy inhibitor Bafilomycin A (Baf A) in AF cells. RESULTS: H2O2 significantly impaired cell viability in a dose- and time-dependent manner. H2O2 also induced a sudden and the highest level of autophagy at 1 h, and gradually increased apoptosis through ERK pathway. The mitochondrial pathway was involved in H2O2-induced apoptosis in AF cells. TGF-ß1 reduced the expression of p-ERK and downregulated the expressions of Beclin-1, LC3 II/I, and mitochondrial-related apoptotic proteins (Bax/Bcl-2, caspase-9). Meanwhile, TGF-ß1 downregulated the level of intracellular H2O2 through upregulating the expression level of glutathione peroxidase-1 (GPx-1). CONCLUSIONS: TGF-ß1 reduced autophagy and apoptosis induced by exogenous H2O2 through downregulating the expression of ERK in AF cells. TGF-ß1 could downregulate the level of ERK and intracellular H2O2 by upregulating GPx-1.


Assuntos
Anel Fibroso/metabolismo , Autofagia/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Estresse Oxidativo/fisiologia , Fator de Crescimento Transformador beta1/farmacologia , Animais , Anel Fibroso/efeitos dos fármacos , Anel Fibroso/patologia , Autofagia/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Relação Dose-Resposta a Droga , Peróxido de Hidrogênio/toxicidade , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley
18.
Nat Commun ; 10(1): 4672, 2019 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-31611553

RESUMO

Naturally occurring chorus emissions are a class of electromagnetic waves found in the space environments of the Earth and other magnetized planets. They play an essential role in accelerating high-energy electrons forming the hazardous radiation belt environment. Chorus typically occurs in two distinct frequency bands separated by a gap. The origin of this two-band structure remains a 50-year old question. Here we report, using NASA's Van Allen Probe measurements, that banded chorus waves are commonly accompanied by two separate anisotropic electron components. Using numerical simulations, we show that the initially excited single-band chorus waves alter the electron distribution immediately via Landau resonance, and suppress the electron anisotropy at medium energies. This naturally divides the electron anisotropy into a low and a high energy components which excite the upper-band and lower-band chorus waves, respectively. This mechanism may also apply to the generation of chorus waves in other magnetized planetary magnetospheres.

19.
Bioresour Technol ; 270: 588-595, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30266031

RESUMO

The aim of this work was to study the regulatory effect of nitrogen (N) deficiency on primary metabolites in Microcystis aeruginosa, and promote the utilization of the alga. Low-N and Non-N conditions, especially Non-N, reduced the cell growth and photosynthetic abilities compared to Normal-N, as N deficiency triggered the down-regulation of genes involving in the photosynthetic process. Non-N not changed lipid content, due to no up-regulation of genes that promoted lipid synthesis. Soluble protein content significantly decreased under Non-N, which may result from the declined expression of genes relating to amino acid and histidyl-transfer RNA synthesis. Soluble and insoluble carbohydrate content significantly increased under Non-N, as the expression variation of genes blocked sugar degradation and promoted lipopolysaccharide synthesis. Therefore, M. aeruginosa can be used as the feedstock to produce carbohydrates under N deficiency for bioethanol production, and the remainder lipids after carbohydrate extraction can be used to produce biodiesel.


Assuntos
Microcystis/metabolismo , Biocombustíveis , Metabolismo dos Carboidratos , Carboidratos , Metabolismo dos Lipídeos , Nitrogênio/metabolismo , Fotossíntese
20.
J Orthop Surg Res ; 12(1): 35, 2017 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-28231839

RESUMO

BACKGROUND: Lateral column tibial plateau fracture fixation with a locking screw plate has higher mechanical stability than other fixation methods. The objectives of the present study were to introduce two newly designed locking anatomic plates for lateral tibial plateau fracture and to demonstrate their characteristics of the fixation complexes under the axial loads. METHODS: Three different 3D finite element models of the lateral tibial plateau fracture with the bone plates were created. Various axial forces (100, 500, 1000, and 1500 N) were applied to simulate the axial compressive load on an adult knee during daily life. The equivalent maps of displacement and stress were output, and relative displacement was calculated along the fracture lines. RESULTS: The displacement and stresses in the fixation complexes increased with the axial force. The equivalent displacement or stress map of each fixation under different axial forces showed similar distributing characteristics. The motion characteristics of the three models differed, and the max-shear stress of trabecula increased with the axial load. CONCLUSIONS: These two novel plates could fix lateral tibial plateau fractures involving anterolateral and posterolateral fragments. Motions after open reduction and stable internal fixation should be advised to decrease the risk of trabecular microfracture. The relative displacement of the posterolateral fragments is different when using anterolateral plate and posterolateral plate, which should be considered in choosing the implants for different posterolateral plateau fractures.


Assuntos
Placas Ósseas , Fixação Interna de Fraturas/instrumentação , Fraturas da Tíbia/cirurgia , Adulto , Análise de Elementos Finitos , Fixação Interna de Fraturas/métodos , Humanos , Articulação do Joelho/fisiopatologia , Masculino , Teste de Materiais/métodos , Modelos Anatômicos , Desenho de Prótese , Estresse Mecânico , Fraturas da Tíbia/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Suporte de Carga
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