Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
1.
Med Sci Monit ; 21: 782-90, 2015 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-25774950

RESUMO

BACKGROUND: The common and effective treatment for degenerative lumbar diseases is lumbar spinal fusion. Controversy still exists on the choice for instrumentation with spinal fusion procedures. Therefore, we conducted this meta-analysis exclusively of RCTs to compare the clinical outcomes of patients receiving bilateral versus unilateral pedicle screw fixation (PSF). MATERIAL AND METHODS: After systematic review of published and unpublished literature, a meta-analysis was conducted to compare the 2 treatment strategies. The methodological quality of the literature was assessed using the PEDro critical appraisal tool. RESULTS: Data synthesis showed less blood loss (P<0.001) and shorter operative time (P<0.001) in patients receiving unilateral PSF compared to bilateral PSF. However, there was no significant difference in fusion rates and functional outcomes between the 2 groups. CONCLUSIONS: The meta-analysis indicated no significant difference in fusion rates and functional outcomes between the 2 treatment procedures, but unilateral PS fixation reduced blood loss and operative time.


Assuntos
Degeneração do Disco Intervertebral/cirurgia , Vértebras Lombares/cirurgia , Parafusos Pediculares , Fusão Vertebral/métodos , Perda Sanguínea Cirúrgica , Hospitalização , Humanos , Tempo de Internação , Duração da Cirurgia , Parafusos Pediculares/efeitos adversos , Cuidados Pós-Operatórios , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento
2.
Nanomaterials (Basel) ; 14(12)2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38921916

RESUMO

A series of TiN/ITO composite films with various thickness of ITO buffer layer were fabricated in this study. The enhancement of optical properties was realized in the composite thin films. The absorption spectra showed that absorption intensity in the near-infrared region was obviously enhanced with the increase of ITO thickness due to the coupling of surface plasma between TiN and ITO. The epsilon-near-zero wavelength of this composite can be tuned from 935 nm to 1895 nm by varying the thickness of ITO thin films. The nonlinear optical property investigated by Z-scan technique showed that the nonlinear absorption coefficient (ß = 3.03 × 10-4 cm/W) for the composite was about 14.02 times greater than that of single-layer TiN films. The theoretical calculations performed by finite difference time domain were in good agreement with those of the experiments.

3.
PLoS One ; 19(4): e0300616, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38598530

RESUMO

This paper presents a groundbreaking Ku-band 20W RF front-end power amplifier (PA), designed to address numerous challenges encountered by satellite communication systems, including those pertaining to stability, linearity, cost, and size. The manuscript commences with an exhaustive discussion of system design and operational principles, emphasizing the intricacies of low-noise amplification, and incorporating key considerations such as noise factors, stability analysis, gain, and gain flatness. Subsequently, an in-depth study is conducted on various components of the RF chain, including the pre-amplification module, driver-amplification module, and final-stage amplification module. The holistic design extends to the inclusion of the display and control unit, featuring the power-control module, monitoring module, and overall layout design of the PA. It is meticulously tailored to meet the specific demands of satellite communication. Following this, a thorough exploration of electromagnetic simulation and measurement results ensues, providing validation for the precision and reliability of the proposed design. Finally, the feasibility of that design is substantiated through systematic system design, prototype production, and exhaustive experimental testing. It is noteworthy that, in the space-simulation environmental test, emphasis is placed on the excellent performance of the Star Ku-band PA within the 13.75GHz to 14.5GHz frequency range. Detailed power scan measurements reveal a P1dB of 43dBm, maintaining output power flatness < ± 0.5dBm across the entire frequency and temperature spectrum. Third-order intermodulation scan measurements indicate a third-order intermodulation of ≤ -23dBc. Detailed results of power monitoring demonstrate a range from +18dBm to +54dBm. Scans of spurious suppression and harmonic suppression, meanwhile, show that the PA evinces spurious suppression ≤ -65dBc and harmonic suppression ≤ -60dBc. Rigorous phase-scan measurements exhibit a phase-shift adjustment range of 0° to 360°, with a step of 5.625°, and a phase-shift accuracy of 0.5dB. Detailed data from gain-scan measurements show a gain-adjustment range of 0dB to 30dB, with a gain flatness of ± 0.5dB. Attenuation error is ≤ 1%. These test parameters perfectly align with the practical application requirements of the technical specifications. When compared to existing Ku-band PAs, our design reflects a deeper consideration of specific requirements in satellite communication, ensuring its outstanding performance and uniqueness. This PA features good stability, high linearity, low cost, and compact modularity, ensuring continuous and stable power output. These features position the proposed system as a leader within the market. Successful orbital deployment not only validates its operational stability; it also makes a significant contribution to the advancement of China's satellite PA technology, generating positive socio-economic benefits.


Assuntos
Amplificadores Eletrônicos , Comunicações Via Satélite , Reprodutibilidade dos Testes , Desenho de Equipamento , Simulação por Computador
4.
Nanomaterials (Basel) ; 13(10)2023 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-37242047

RESUMO

The nonlinear optical (NLO) response of indium tin oxide films covered with Au@Ag colloid layer was characterized by a femtosecond single-beam open aperture (OA) Z-scan technique in this study. As the Au@Ag thickness increased, the transition from saturated absorption (SA) to reverse saturated absorption (RSA) was found in these ITO matrix composites. The nonlinear absorption coefficient for these composite materials can be regulated from -6.85 × 10-7 m/W to 26.06 × 10-7 m/W. In addition, this work also characterized the structure, morphology, and other optical properties of the specimen, and the finite-difference time-domain (FDTD) results were consistent with the experimental results. The NLO response of the ITO/Au@Ag composites can be attributed to the phase properties, synergistic competition effect, strong interaction based on the epsilon-near-zero (ENZ) mode, and localized surface plasmon resonance (LSPR) between the indium tin oxide films and Au@Ag.

5.
World Neurosurg ; 167: e1253-e1260, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36075355

RESUMO

PURPOSE: In this study, a large diameter visible trephine was designed and used in percutaneous endoscopic lumbar interbody fusion to increase endoscopic bone decompression efficiency. Large diameter visible trephine-related technical notes and preliminary clinical experience are described. METHODS: A large diameter visible trephine was designed with normal diameter visible trephine as template. A total of 38 patients with lumbar degenerative diseases who underwent single-level percutaneous endoscopic lumbar interbody fusion with large or normal diameter visible trephine were included into a retrospective study. Operation time, bone decompression time, blood loss, intraoperative fluoroscopy, bone decompression fluoroscopy, and dura or nerve injury cases were recorded and analyzed statistically. Visual Analog Scale (VAS) scores and Oswestry Disability Index (ODI) were used to analyze the clinical outcomes of the 2 groups. RESULTS: The baseline data of the 2 groups were statistically similar. There was no significant difference in postoperative VAS and ODI scores between the 2 groups. Operation time and bone decompression time of large diameter visible trephine group were significantly shorter than that of normal diameter visible trephine group (P < 0.05). Intraoperative fluoroscopy times and bone decompression fluoroscopy times of large diameter visible trephine group were significantly more than that of normal diameter visible trephine group (P < 0.05). Blood loss of the 2 groups were not statistically different. There were no dura or nerve injury cases in the 2 groups. CONCLUSIONS: For percutaneous endoscopic lumbar interbody fusion, the large diameter visible trephine is a safe and efficient endoscopic bone decompression tool under fluoroscopic guidance.


Assuntos
Fusão Vertebral , Humanos , Resultado do Tratamento , Estudos Retrospectivos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Endoscopia , Procedimentos Cirúrgicos Minimamente Invasivos
6.
Life Sci ; 236: 116948, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31605711

RESUMO

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Given the comments of Dr Elisabeth Bik regarding this article "… the Western blot bands in all 400+ papers are all very regularly spaced and have a smooth appearance in the shape of a dumbbell or tadpole, without any of the usual smudges or stains. All bands are placed on similar looking backgrounds, suggesting they were copy/pasted from other sources, or computer generated", the journal requested the authors to provide the raw data. However, the authors were not able to fulfil this request and therefore the Editor-in-Chief decided to retract the article.


Assuntos
Apoptose/efeitos dos fármacos , Autofagia , Fármacos do Sistema Nervoso Central/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Ginsenosídeos/farmacologia , Peróxido de Hidrogênio/toxicidade , MicroRNAs/genética , Animais , Oxidantes/toxicidade , Células PC12 , Ratos , Transdução de Sinais
7.
Nanomaterials (Basel) ; 9(6)2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31167393

RESUMO

Sub-wavelength artificial photonic structures can be introduced to tailor and modulate the spectrum of materials, thus expanding the optical applications of these materials. On the basis of SiO2/Cu/ITO arrays, a hybrid coupled resonance (HCR) mechanism, including the epsilon-near-zero (ENZ) mode of ITO, local surface plasmon resonance (LSPR) mode and the microstructural gap resonance (GR) mode, was proposed and researched by systematically regulating the array period and layer thickness. The optical absorptions of the arrays were simulated under different conditions by the finite-difference time-domain (FDTD) method. ITO films were prepared and characterized to verify the existence of ENZ mode and Mie theory was used to describe the LSPR mode. The cross-sectional electric field distribution was analyzed while SiO2/Cu/ITO multilayers were also fabricated, of which absorption was measured and calculated by Macleod simulation to prove the existence of GR and LSPR mode. Finally, the broad-band tailoring of optical absorption peaks from 673 nm to 1873 nm with the intensities from 1.8 to 0.41 was realized, which expands the applications of ITO-based plasmonic metamaterials in the near infrared (NIR) region.

8.
Zhongguo Gu Shang ; 32(10): 933-936, 2019 Oct 25.
Artigo em Zh | MEDLINE | ID: mdl-32512965

RESUMO

OBJECTIVE: To investigate the clinical effects of percuteneous endoscopic interlaminar discectomy(PEID)and fenestration discectomy(FD) for the treatment of L5S1 lumbar disc herniation(LDH). METHODS: A retrospective analysis was made on 86 patients with L5S1 LDH from January 2014 to March 2017 and followed up. According to the different surgical methods, the patients were divided into PEID group(43 cases) and FD group(43 cases). All operations were performed under general anesthesia. Forty-three patients in PEID group underwent percuteneous endoscopic interlaminar discectomy (PEID) and other 43 patients in FD group underwent classical fenestration discectomy (FD). Operative incision, operative time, intraoperative blood loss, duration of hospitalization, time of lying in bed after surgery, complication were compared between two groups. Pre- and postoperative visual analogue scale(VAS) of affected extremity pain and lumbar pain were recorded. Postoperative creatine kinase (CK) was observed in two groups. Modified Macnab criteria was used to evaluate the clinical effects. MRI was used to observe the survival rate of paraspinal muscle after operation. RESULTS: The length of skin incision, intraoperative blood loss, duration of hospitalization, time of lying in bed after surgery of PEID group and FD group were(0.7±0.1) cm, (8.0±3.0) ml, (3.0±1.5) d, (1.0±0.5) d and(5.0±1.8) cm, (62.0±50.5) ml, (11.0±2.5) d, (3.0±0.8) d, there was significant differences between two groups(P<0.05). VAS of affected extremity at 24 hours and 1 year after operation was obviously decreased in two groups(P<0.05), but there was no significant difference between groups(P>0.05). VAS of lumbar pain in PEID group and FD group were respectively (2.99±0.32), (5.44±1.31) scores at 24 hours after operation, and (1.56±0.60), ( 3.05±0.24) at 1 year after operation, there was significant differences between two groups(P<0.05). CK at 24, 48 hours after operation of FD group were obviously increased(P<0.05). According the modified Macnab criteria to evaluate the clinical effect, the rate of excellent and good of PEID group and FD group were 93% and 95%, respectively. The survival rate of paraspinal muscle by MRI in PEID group at 1 year after operation was higher than that in FD group(P<0.05). No complications such as spinal dura mater tearing, nerve root injury, vascular injury, intervertebral space infection were found in two groups. CONCLUSIONS: Both of the two methods are safe and can obtain satisfactory effect, but PEID is more in line with concept of minimally invasive and has more advantages in paraspinal muscle protection, operative incision, intraoperative blood loss, duration of hospitalization, time of lying in bed after operation.


Assuntos
Discotomia Percutânea , Discotomia , Deslocamento do Disco Intervertebral , Humanos , Deslocamento do Disco Intervertebral/cirurgia , Vértebras Lombares , Neuroendoscopia , Estudos Retrospectivos , Resultado do Tratamento
9.
Mol Med Rep ; 18(6): 5221-5228, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30280196

RESUMO

Emerging evidence has demonstrated that the dysregulation of microRNA (miRNA/miR) serves a crucial role in the tumorigenesis and tumor development of osteosarcoma (OS), primarily by affecting various pathological behaviors. Therefore, better knowledge of miRNA in OS may provide novel insights into the pathogenesis of OS, and may facilitate the development of promising therapeutics for patients with this disease. MiRNA­944 is frequently dysregulated in human cancers. However, the expression levels, functions and underlying mechanisms of miR­944 in OS remain largely elusive. In the present study, reverse transcription­quantitative polymerase chain reaction (RT­qPCR) was performed to detect miR­944 expression in OS tissues and cell lines. The regulatory influence of miR­944 in OS proliferation and invasion was determined with MTT and Transwell invasion assays. In addition, the mechanisms underlying the action of miR­944 in OS cells were elucidated through a series of experiments, including bioinformatics analysis, luciferase reporter assay, RT­qPCR and western blot analysis. Spearman's correlation analysis was utilized to examine the relationship between miR­944 and VEGF expression levels, and rescue experiments were applied to further verify whether VEGF mediates the role of miR­944 in OS. The results demonstrated that miR­944 was downregulated in cancer tissues and cell lines. Furthermore, exogenous miR­944 expression inhibited cell proliferation and invasion in OS in vitro. Vascular endothelial growth factor (VEGF) was identified as a direct target of miR­944 in OS and was overexpressed in cancer tissues. VEGF expression was inversely correlated with miR­944 expression in cancer tissues. Rescue experiments demonstrated that overexpression of VEGF partially prevented the miR­944­induced inhibition of OS cell proliferation and invasion. These results suggested that miR­944 may serve a tumor suppressive role in OS by directly targeting VEGF. Therefore, miR­944 may be a promising target in the treatment of OS.


Assuntos
Neoplasias Ósseas/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Osteossarcoma/genética , Interferência de RNA , Fatores de Crescimento do Endotélio Vascular/genética , Regiões 3' não Traduzidas , Biomarcadores Tumorais , Neoplasias Ósseas/mortalidade , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Humanos , Osteossarcoma/mortalidade , Osteossarcoma/patologia , Prognóstico
12.
Neural Regen Res ; 11(11): 1816-1823, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28123427

RESUMO

Some studies have indicated that the Wnt/ß-catenin signaling pathway is activated following spinal cord injury, and expression levels of specific proteins, including low-density lipoprotein receptor related protein-6 phosphorylation, ß-catenin, and glycogen synthase kinase-3ß, are significantly altered. We hypothesized that methylprednisolone treatment contributes to functional recovery after spinal cord injury by inhibiting apoptosis and activating the Wnt/ß-catenin signaling pathway. In the current study, 30 mg/kg methylprednisolone was injected into rats with spinal cord injury immediately post-injury and at 1 and 2 days post-injury. Basso, Beattie, and Bresnahan scores showed that methylprednisolone treatment significantly promoted locomotor functional recovery between 2 and 6 weeks post-injury. The number of surviving motor neurons increased, whereas the lesion size significantly decreased following methylprednisolone treatment at 7 days post-injury. Additionally, caspase-3, caspase-9, and Bax protein expression levels and the number of apoptotic cells were reduced at 3 and 7 days post-injury, while Bcl-2 levels at 7 days post-injury were higher in methylprednisolone-treated rats compared with saline-treated rats. At 3 and 7 days post-injury, methylprednisolone up-regulated expression and activation of the Wnt/ß-catenin signaling pathway, including low-density lipoprotein receptor related protein-6 phosphorylation, ß-catenin, and glycogen synthase kinase-3ß phosphorylation. These results indicate that methylprednisolone-induced neuroprotection may correlate with activation of the Wnt/ß-catenin signaling pathway.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA