Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Adv ; 5(9): eaax0800, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31523711

RESUMO

Mobile gravimetry is important in metrology, navigation, geodesy, and geophysics. Atomic gravimeters could be among the most accurate mobile gravimeters but are currently constrained by being complex and fragile. Here, we demonstrate a mobile atomic gravimeter, measuring tidal gravity variations in the laboratory and surveying gravity in the field. The tidal gravity measurements achieve a sensitivity of 37 µGal/ Hz (1 µGal = 10 nm/s2) and a long-term stability of better than 2 µGal, revealing ocean tidal loading effects and recording several distant earthquakes. We survey gravity in the Berkeley Hills with an uncertainty of around 0.04 mGal and determine the density of the subsurface rocks from the vertical gravity gradient. With simplicity and sensitivity, our instrument paves the way for bringing atomic gravimeters to field applications.

2.
Biochem Biophys Res Commun ; 519(2): 430-437, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31522815

RESUMO

Osteoarthritis (OA) is a common and frequently-occurring disease in middle-aged and older people. A growing number of studies have shown that microRNAs (miRNAs) are involved in the development of OA. However, the role and mechanism of miR-33b-3p in OA remain ill-defined. The levels of miR-33b-3p and DNA methyltransferase 3A (DNMT3A) mRNA were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The levels of DNMT3A protein, matrix metalloprotein 13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motif-5 (ADAMTS-5), collagen II, aggrecan, cleaved Caspase-3, B-cell lymphoma-2 (Bcl-2) and BCL2-Associated X (Bax) were measured by Western blot assay. Cell proliferation and cell apoptosis were assessed by Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis, respectively. The targeting relationship between miR-33b-3p and DNMT3A was verified by dual-luciferase reporter assay. The expression of miR-33b-3p was decreased and the expression of DNMT3A was increased in OA cartilage tissues and IL-1ß-induced chondrocytes. There was an inverse correlation between miR-33b-3p and DNMT3A in OA cartilage tissues. MiR-33b-3p overexpression or DNMT3A knockdown inhibited extracellular matrix (ECM) degradation and cell apoptosis and promoted cell proliferation in IL-1ß-induced chondrocytes. Moreover, DNMT3A was confirmed to be a direct target of miR-33b-3p. Upregulation of DNMT3A weakened the effects of miR-33b-3p overexpression on cartilage ECM degradation, cell proliferation and apoptosis in IL-1ß-activated chondrocytes. MiR-33b-3p overexpression suppressed cartilage ECM degradation and cell apoptosis, and promoted cell proliferation by directly targeting DNMT3A in IL-1ß-stimulated chondrocytes.

3.
Rev Sci Instrum ; 90(7): 073103, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31370459

RESUMO

Atom interferometers require precise control of digital, analog, and radio frequency signals for effective operation. In this paper, we propose and implement a control system for mobile atom interferometers. The system consists of a microcontroller and peripherals to synthesize radio frequency signals and to read or write analog signals. We use the system to operate a mobile atomic gravimeter by controlling 7 analog outputs, 16 digital outputs, 2 radio frequency channels, and 1 analog input. Our control system eliminates dead time between repetitions of the measurement and, consequently, improves the sampling rate of our atomic gravimeter, while maintaining the sensitivity per repetition compared to the system based on a desktop computer.

4.
Biomed Pharmacother ; 118: 109180, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31302422

RESUMO

BACKGROUND: Astragalus polysaccharide (APS) is a traditional Chinese herbal medicine with anti-inflammatory and anti-aging activities. OBJECTIVE: This study aimed to explore the effect and associated mechanisms of APS on LPS-induced injury in ATDC5 cells, to evaluate the potential of APS for use as an adjuvant therapy for osteoarthritis (OA). MATERIALS AND METHODS: ATDC5 cells were pre-treated with APS and stimulated with lipopolysaccharide (LPS). Cell viability, ROS generation as well as the expression of IL-6, TNF-α, iNOS and Cox-2 were evaluated by performing CCK8 assay, ROS detection, ELISA, western blot and qRT-PCR. The expression of NF-κB and p38MAPK signal pathways related proteins and KLF4 was measured through western blot. RESULTS: LPS increased the expression of IL-6 and TNF-α, elevated the expression of Cox-2, iNOS and increased ROS generation. APS treatment significantly alleviated LPS-induced damage in ATDC5 cells. Besides, miR-92a was down-regulated while KLF4 was up-regulated by APS. At the same time, the targeting relationship between miR-92a and KLF4 was demonstrated. The inhibitory effects of APS on LPS-induced injury in ATDC5 cells were attenuated by the combination of KLF4 siRNA. In addition, LPS induced NF-κB and p38MAPK signal pathways were decreased by APS treatment. Also, the inhibitory effect of APS on NF-κB and p38MAPK signal pathways was reversed by KLF4 siRNA. CONCLUSIONS: The present study reveals that APS protects ATDC5 cells against LPS induced-injury by regulation of miR-92a/KLF4 axis and suppressing NF-κB and p38MAPK signal pathways.

5.
Cancer Med ; 8(8): 3981-3991, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31150156

RESUMO

Osteosarcoma is the most common type of primary malignant tumor of skeletal with poor prognosis in children and adolescents. Accumulating evidence indicates that CBX2 is overexpressed in multiple human neoplasm and play a critical role in tumorigenesis and progression. However, its functional role and upstream regulation mechanism in osteosarcoma remain unknown. In the present study, tissue microarray (TMA) analysis was performed to determine the association between CBX2 expression and clinical prognosis of osteosarcoma patients by immunohistochemistry. We also investigated the functional role of CBX2 using small interfering RNA (siRNA) in vitro and in vivo. Additionally, we confirmed the direct binding between CBX2 and let-7a via qPCR, western blot and luciferase reporter assay. We found that CBX2 is dramatically upregulated in osteosarcoma tissues and high CBX2 expression was correlated with metastasis, recurrence, and chemotherapy response, as well as unfavorable prognosis in patients with osteosarcoma. Similar results were observed in a sarcoma cohort from The Cancer Genome Atlas (TCGA) dataset. Further experiments revealed that CBX2 knockdown significantly impeded osteosarcoma cell proliferation and invasion ability in vitro, and suppressed the tumor growth in tumor xenografts model. Mechanistically, we confirmed that CBX2 is a functional target of miRNA let-7a. Overexpression of let-7a inhibits osteosarcoma cell proliferation, which was reversed by CBX2 overexpression. Taken together, our study demonstrates that let-7a/CBX2 plays a crucial role in osteosarcoma progression. CBX2 could serve as a promising prognostic biomarker and potential therapeutic target for osteosarcoma patients.

6.
J Mol Neurosci ; 68(2): 181-190, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30911940

RESUMO

Microglial activation and inflammatory response played an important role in the secondary injury of spinal cord injury (SCI). Several microRNAs were associated with this procedure, but the underlying molecular mechanism was poorly understood. Sprague-Dawley (SD) rats were divided into four groups: SCI group (n = 7), agomiR-325-3p group (n = 7), and their control groups. Expression of miR-325-3p and proteins in epidermal growth factor receptor (EGFR)/mitogen-activated protein kinase (MAPK) signaling pathway was evaluated in microglia from SCI rats and primary microglia/BV2 cells activated by lipopolysaccharide (LPS). Concentrations of interleukin-1ß (IL-1ß) and tumor necrosis factor α (TNF-α) in supernatants were measured by ELISA. Low expression of miR-325-3p and activation of EGFR/MAPK was observed in microglia of SCI and LPS-induced primary microglia. Overexpression of miR-325-3p in LPS-induced BV2 cells inhibited microglial activation and release of TNF-α and IL-1ß. Luciferase reporter assay confirmed that miR-325-3p negatively regulated EGFR by targeting its 3'-untranslated regions. Additionally, agomiR-325-3p inhibited the activation of microglia and EGFR/MAPK, alleviating the inflammatory response. These results indicated that miR-325-3p attenuated secondary injury after SCI through inhibition of EGFR/MAPK signaling pathway, the microglial activation, and the release of inflammatory cytokines, suggesting that miR-325-3p may be employed as a therapeutic target for SCI.


Assuntos
Receptores ErbB/metabolismo , Sistema de Sinalização das MAP Quinases , MicroRNAs/genética , Microglia/metabolismo , Traumatismos da Medula Espinal/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Receptores ErbB/genética , Interleucina-1beta/metabolismo , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , MicroRNAs/metabolismo , Microglia/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Traumatismos da Medula Espinal/genética
7.
Technol Cancer Res Treat ; 17: 1533033818811143, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30482097

RESUMO

Osteosarcoma is a highly malignant bone tumor. However, due to the high complexity of the occurrence and metastasis of osteosarcoma, the exact mechanism promoting its development and progression remains to be elucidated. This study highlights the causal link between solute carrier family 25 member 22 (SLC25A22) and the development, progression, and metastasis of osteosarcoma. SLC25A22 is upregulated in human osteosarcoma and predicts a poor prognosis. The upregulation of SLC25A22 in osteosarcoma tissues was significantly associated with cell proliferation, invasion, and metastasis. Studies of functional gain (overexpression) and loss (knockdown) showed that SLC25A22 significantly increases the ability of osteosarcoma cells to proliferate, as well as invade and metastasize in vitro. At the same time, the expression of SLC25A22 promoted the progression of the cellcycle of osteosarcoma cell lines and inhibited the apoptosis of osteosarcoma cells. Analysis using a mouse xenograft model showed that xenografts of SLC25A22 stable overexpressing osteosarcoma cells had a significant increase in tumor volume and weight compared to the control group. Lung metastasis models in mice showed that expression of SLC25A22 promoted lung metastasis of osteosarcoma in vivo. Furthermore, SLC25A22 inhibited phosphatase and tensin homolog expression and increased phosphorylation of protein kinase b (Akt) and Focal Adhesion Kinase (FAK) in the phosphatase and tensin homolog signaling pathway. In summary, SLC25A22 is highly expressed in osteosarcoma, promoting osteosarcoma cell proliferation and invasion by inhibiting the phosphatase and tensin homolog signaling pathway.

8.
Biosci Rep ; 2018 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-30135141

RESUMO

Various of microRNAs (miRNAs) have been reported to regulate the chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), however, whether miR-134 plays a role in this biological process remains undetermined. In this present study, we firstly evaluated the chondrogenic differentiation of BMSCs by Alcian blue staining, and examined the miR-134 expression by qRT-PCR during this process. And miR-134 inhibitor was used to investigate the functions of miR-134 in chondrogenic differentiation of BMSCs by Alcian blue staining, qRT-PCR and western blot. Subsequently, the correlation between miR-134 and SMAD6 was assessed via bioinformatics analysis and dual luciferase reporter assay. Finally, the roles of SMAD6 in chondrogenic differentiation of BMSCs was also determined through Alcian blue staining, qRT-PCR and western blot. As results showed that miR-134 expression was significantly downregulated during chondrogenic differentiation, and inhibition of miR-134 obviously promoted chondrogenic differentiation. Dual luciferase reporter assay indicated that miR-134 could directly targeted the 3'-UTR of SMAD6, inhibited miR-134 expression in BMSCs could upregulate SMAD6 expression. Moreover, we found that overexpression of SMAD6 significantly promoted chondrogenic differentiation, and this SMAD6 induced promotion of chondrogenic differentiation could be reversed by miR-134 mimics. In conclusion, our findings suggested that miR-134 may act as a negative regulator during chondrogenic differentiation of BMSCs by interacting with SMAD6.

9.
Biomed Pharmacother ; 103: 1238-1245, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29864904

RESUMO

Long non-coding RNA P73 antisense RNA 1 T (lncRNA TP73-AS1) has been shown to involve in the progression of numerous tumors. Nevertheless, the expression as well as the functional mechanisms of TP73-AS1 in osteosarcoma (OS) are still largely unknown. This study aimed to explore the roles and underlying mechanism of TP73-AS1 in OS progression. In thye present study, TP73-AS1 expression was significantly increased in OS tissues and cell lines. High TP73-AS1 expression was associated with poor overall survival of OS patients. TP73-AS1 knockdown suppressed OS cells proliferation and invasion in vitro as well as tumor growth in vivo. Furthermore, we identified that miR-142 could act as a direct target for TP73-AS1 and miR-142 inhibition reversed the suppression of OS cells proliferation and invasion induced by TP73-AS1 knockdown. In addition, we showed that TP73-AS1 could function as a sponge of miR-142 to positively regulate Rac1 in OS cells. Thus, our data suggested that TP73-AS1 served as an oncogenic lncRNA in OS progression, and could be regarded as an efficient therapeutic target in the treatment of OS.


Assuntos
Técnicas de Silenciamento de Genes , MicroRNAs/metabolismo , Osteossarcoma/genética , Osteossarcoma/patologia , RNA Longo não Codificante/metabolismo , Animais , Sequência de Bases , Linhagem Celular Tumoral , Proliferação de Células/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , MicroRNAs/genética , Invasividade Neoplásica , Prognóstico , RNA Longo não Codificante/genética , Regulação para Cima/genética , Adulto Jovem , Proteínas rac1 de Ligação ao GTP/metabolismo
10.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 32(2): 182-186, 2018 Feb 01.
Artigo em Chinês | MEDLINE | ID: mdl-29806409

RESUMO

Objective: To evaluate the effectiveness of Ilizarov technique combined with soft tissue release and muscle strength balance in the treatment of spastic clubfoot in adolescents with cerebral palsy. Methods: A retrospective analysis of clinical data of 29 cases (33 feet) of cerebral palsy spastic clubfoot deformity conformed to the selection criteria between June 2011 and September 2016. Among them, 17 were male (20 feet) and 12 were female (13 feet) with an age range from 13 to 28 years (mean, 17.6 years). According to Diméglio classification, 19 feet were rated as gradeⅡ and 14 feet as grade Ⅲ. All patients were treated with soft tissue release and muscle balance, while using Ilizarov technique to correct varus deformity. Began to gradually adjust the external fixator after 5-7 days of operation, until to reach satisfactory foot ankle form. Orthopedic brace was used after removal of external fixator, and the wearing time gradually reduced to completely abandon the brace. Results: All 29 patients (33 feet) were followed up 12-22 months with an average of 18 months. All patients restored line plantar foot without needle infection and nerve or vessel injury. One foot had a mild relapse of deformity at 6 months after removal of external fixator, and the gait restored to normal after symptomatic treatment. The rest of 32 feet had no deformity recurrence during the follow-up. At last follow-up, International Club Foot Study Group (ICFSG) score (5.21±3.91) was significantly lower than the preoperative score (36.73±4.80), and the difference was significant ( t=47.227, P=0.000). The results were excellent in 27 feet, good in 3 feet, and fair in 3 feet, and the excellent and good rate was 90.91%. The patients were very satisfied in 27 feet and satisfied in 6 feet by self-evaluation of effectiveness. Conclusion: Ilizarov technique is effective in treatment of clubfoot. And it is also a feasible method to treat spastic clubfoot in adolescents with cerebral palsy when combined with appropriate soft tissue surgery according to the patient's symptoms and signs.


Assuntos
Paralisia Cerebral/complicações , Pé Torto Equinovaro/cirurgia , Fixadores Externos , Técnica de Ilizarov , Espasticidade Muscular/cirurgia , Força Muscular/fisiologia , Adolescente , Adulto , Braquetes , Feminino , Seguimentos , Marcha , Hallux Varus , Humanos , Extremidade Inferior , Masculino , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
11.
Front Pharmacol ; 9: 64, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29472860

RESUMO

Lipopolysaccharide (LPS) can induce bone loss by stimulating bone resorption. Natural compounds have great potential for the treatment of osteolytic bone diseases. Magnesium lithospermate B (MLB) plays an important role in protecting against oxidative damage and also has potential anti-inflammatory pharmacological properties. However, its role in LPS-induced bone loss is still unknown. In the present study, we observed the effects of MLB on LPS-induced bone damage and investigated the possible mechanisms. The bone loss models were established by LPS administration in male Sprague-Dawley rats. MLB (200 mg/kg body weight) was given by subcutaneous injection. MicroCT analysis, biomarker assay, histological examination and immunohistochemical staining were performed at the 8th weeks. In addition, RAW264.7 cells were treated with LPS in the presence or absence of MLB. The osteoclast formation, resorption activity and differentiation-related genes [(receptor activator of nuclear factor kappa-B (RANK), Traf6, Fra-1, and c-src)] expression were evaluated. LPS induced bone loss shown as the decrease in bone volume fraction and trabecular number, and increase in trabecular separation. LPS also markedly enhanced the osteoclast formation and resorption activity compared with the control. MLB significantly abolished the LPS-induced bone microstructure damage (p < 0.05) and osteoclast formation. MLB also inhibited the increases of serum tartrate-resistant acid phosphatase 5b, RANK ligand (RANKL) and TNF-α level enhanced by LPS (p < 0.05). Immunohistochemical staining indicated that MLB attenuated the high expression of RANKL and RANK stimulated by LPS. In addition, MLB significantly abolished the LPS-enhanced osteoclast formation, resorption activity, RANK, Traf6, Fra-1, and c-src expression in vitro. Our data demonstrate that MLB can suppress LPS-induced bone loss via inhibiting RANKL/RANK related osteoclast formation.

12.
Appl Opt ; 57(5): 1247-1253, 2018 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-29469871

RESUMO

A precise 3D surface measurement method for large stepped structures without height ambiguity is proposed based on optical-frequency-comb-referenced frequency-sweeping interferometry and Fourier-transformed fractional phase retrieval. Unlike other interferometry that depends on the absolute phase value for several certain wavelengths, this method obtains results from the phase change during frequency sweeping and thus remains free from the confined non-ambiguity range. By reference to an optical frequency comb, the relative uncertainty from the tunable laser frequency was reduced by three orders of magnitude, and the sweeping frequency range can be precisely determined. Besides, the fractional phase can be rapidly retrieved in only one step using a Fourier transform method, with advantages of high accuracy and immunity to light intensity fluctuation and mechanical vibration noise. Samples of step heights from 1 µm to 1 mm were measured, and the standard uncertainty was 45 nm. This permits applications such as quality assurance in microelectronics production and micro-electro-mechanical system (MEMS) manufacture.

13.
Biomed Pharmacother ; 97: 905-910, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29136768

RESUMO

Spinal cord injury (SCI) is a devastating physical trauma worldwide. The mechanisms of SCI are still not clear and the effective treatment is limited. Lipoxin A4 (LXA4) possesses anti-inflammatory and neuroprotective effects. The present study was designed to further evaluate the molecular mechanisms of LXA4-induced protective effects in a rat model of SCI. We found that LXA4 increased Basso, Beattie and Bresnahan (BBB) scores, increased mechanical paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) to a radiant heat, reduced the lesion volume, decreased Bax mRNA expression and increased Bcl-2 expression after SCI. The phosphorylation of Akt and protein expression of Nrf2 and HO-1 were reduced after SCI. LXA4 treatment significantly inhibited the reduction of Akt phosphorylation and Nrf2 and HO-1 protein expression. Injection of LY294002 notably inhibited the phosphorylation of Akt, and the expression of total Akt and Nrf2 and HO-1 after SCI in LXA4-treated rats. LY294002 prohibited LXA4-induced effects after SCI. shNrf2 injection markedly decreased both Nrf2 and HO-1 expression in LXA4-treated rats after SCI. ZnPP notably decreased HO-1 expression but did not markedly affect Nrf2 expression. shNrf2 and ZnPP prohibited LXA4-induced increase of BBB scores, and PWT and PWL, decrease of lesion volume of spinal cord, reduction of Bax expression and increase of Bcl-2 expression. The results indicate that LXA4 protects against SCI through Akt/Nrf2/HO-1 signaling. The data provide novel insights into the mechanisms of LXA4-mediated neuprotective effects against SCI and suggest that LXA4 may be a potential therapeutic agent for SCI and its associated complications.


Assuntos
Lipoxinas/farmacologia , Fármacos Neuroprotetores/farmacologia , Traumatismos da Medula Espinal/tratamento farmacológico , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Cromonas/farmacologia , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Heme Oxigenase-1/metabolismo , Masculino , Morfolinas/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Traumatismos da Medula Espinal/fisiopatologia
14.
Biomed Pharmacother ; 95: 207-214, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28843909

RESUMO

RSF1 (HBXAP), is a member of ATP-dependent chromatin remodeling factor. Dysregulated RSF1 has been reported to be related to tumor progression. However, the function of RSF1 in osteosarcoma (OS) remains unclear. In this study, we showed that RSF1 expression was upregulated in OS cells. RSF1 inhibition suppressed OS cell proliferation and invasion. We further showed that MAPK/Erk signaling pathway was inactivated by RSF1 suppression. In addition, RSF1 was identified as a direct target of miR-193a-3p. Clinically, RSF1 was increased and associated with advanced clinical features and poor overall survival of OS patients. MiR-193a-3p expression was decreased and associated with advanced clinical features and poor overall survival of OS patients. In addition, we found that miR-193a-3p was negatively correlated with RSF1 expression in OS tissues. Moreover, our data showed that XIST could function as competing endogenous RNA to repress miR-193a-3p, which regulated its downstream target RSF1. In conclusion, our findings demonstrated that the XIST/miR-193a-3p/RSF1 axis might contribute to the progression and act as a therapeutic target of OS patients.


Assuntos
Neoplasias Ósseas/metabolismo , MicroRNAs/fisiologia , Proteínas Nucleares/fisiologia , Oncogenes/fisiologia , Osteossarcoma/metabolismo , RNA Longo não Codificante/fisiologia , Transativadores/fisiologia , Adulto , Animais , Neoplasias Ósseas/genética , Neoplasias Ósseas/mortalidade , Linhagem Celular Tumoral , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Nus , Osteossarcoma/genética , Osteossarcoma/mortalidade , Transdução de Sinais/fisiologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Adulto Jovem
15.
Appl Opt ; 56(11): 3109-3115, 2017 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-28414369

RESUMO

The absolute group refractive index of air at 194061.02 GHz is measured in real time using frequency-sweeping interferometry calibrated by an optical frequency comb. The group refractive index of air is calculated from the calibration peaks of the laser frequency variation and the interference signal of the two beams passing through the inner and outer regions of a vacuum cell when the frequency of a tunable external cavity diode laser is scanned. We continuously measure the refractive index of air for 2 h, which shows that the difference between measured results and Ciddor's equation is less than 9.6×10-8, and the standard deviation of that difference is 5.9×10-8. The relative uncertainty of the measured refractive index of air is estimated to be 8.6×10-8. The data update rate is 0.2 Hz, making it applicable under conditions in which air refractive index fluctuates fast.

16.
Appl Opt ; 56(10): 2649-2652, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28375231

RESUMO

We present a hybrid laser frequency stabilization method combining modulation transfer spectroscopy (MTS) and frequency modulation spectroscopy (FMS) for the cesium D2 transition. In a typical pump-probe setup, the error signal is a combination of the DC-coupled MTS error signal and the AC-coupled FMS error signal. This combines the long-term stability of the former with the high signal-to-noise ratio of the latter. In addition, we enhance the long-term frequency stability with laser intensity stabilization. By measuring the frequency difference between two independent hybrid spectroscopies, we investigate the short-and long-term stability. We find a long-term stability of 7.8 kHz characterized by a standard deviation of the beating frequency drift over the course of 10 h and a short-term stability of 1.9 kHz characterized by an Allan deviation of that at 2 s of integration time.

17.
Appl Opt ; 55(34): D29-D34, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27958436

RESUMO

We present an optically stabilized Erbium fiber frequency comb with a broad repetition rate tuning range based on a hybrid mode-locked oscillator. We lock two comb modes to narrow-linewidth reference lasers in turn to investigate the best performance of control loops. The control bandwidth of fast and slow piezoelectric transducers reaches 70 kHz, while that of pump current modulation with phase-lead compensation is extended to 32 kHz, exceeding laser intrinsic response. Eventually, simultaneous lock of both loops is realized to totally phase-stabilize the comb, which will facilitate precision dual-comb spectroscopy, laser ranging, and timing distribution. In addition, a 1.8-MHz span of the repetition rate is achieved by an automatic optical delay line that is helpful in manufacturing a secondary comb with a similar repetition rate. The oscillator is housed in a homemade temperature-controlled box with an accuracy of ±0.02 K, which not only keeps high signal-to-noise ratio of the beat notes with reference lasers, but also guarantees self-starting at the same mode-locking every time.

18.
Oncol Lett ; 12(3): 1840-1848, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27602115

RESUMO

There is increasing evidence that microRNAs (miRs) are implicated in tumor development and progression; however, their specific roles in osteosarcoma are not well understood. The aim of the present study was to investigate the role of miR-506 in the pathogenesis of osteosarcoma. The expression levels of miR-506 and astrocyte elevated gene-1 (AEG-1) mRNA were detected using quantitative polymerase chain reaction, and the protein levels of AEG-1, ß-catenin, c-myc and cyclin D1 were determined using western blot analysis. The effects of miR-506 and AEG-1 on cell viability, colony forming ability and apoptosis were assessed using MTT assay, colony formation assay, and flow cytometry, respectively. Lucifer reporter assays were used to demonstrate whether AEG-1 is a direct target of miR-506. The present study identified that miR-506 was downregulated in osteosarcoma tissues and cells. Overexpression of miR-506 suppressed the proliferation and induced apoptosis in osteosarcoma cells in vitro and inhibited tumor formation in vivo. Overexpression of miR-506 significantly inhibited the luciferase activity of AEG-1 with a wild-type 3'-untranslated region, providing clear evidence that AEG-1 was a direct and functional downstream target of miR-506. Similar to the overexpression of miR-506, downregulation of AEG-1 lead to an inhibitory effect on osteosarcoma in vitro. Furthermore, overexpression of miR-506 or downregulation of AEG-1 inhibited the Wnt/ß-catenin signaling pathway, and inhibition of this pathway by ß-catenin small interfering RNA or CGP049090, a small molecule inhibitor, suppressed cell proliferation and induced apoptosis in vitro. Overall, the present data indicated that miR-506 functions as a tumor suppressor by targeting AEG-1 in osteosarcoma via the regulation of the Wnt/ß-catenin signaling pathway.

19.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 30(12): 1452-1456, 2016 Dec 08.
Artigo em Chinês | MEDLINE | ID: mdl-29786332

RESUMO

OBJECTIVE: To investigate the application value of the Ilizarov technique for infection after the limb salvage operation of primary bone tumor. METHODS: A retrospective analysis was made on the clinical data of 6 patients with infection treated with Ilizarov technique after limb salvage operation of primary bone tumor between July 2012 and April 2015. There were 4 males and 2 females, aged 18-40 years (mean, 28 years). Tumor types included 3 cases of osteosarcoma and 3 cases of giant cell tumor of bone. Tumor located at the left distal femur in 2 cases, at the right distal femur in 1 case, at the left proximal tibia in 1 case, and at the right proximal tibia in 2 cases. Six cases had recurring infection after debridement. The patients underwent operation 2 to 5 times (mean, 3.5 times). The time from tumor resection to visiting was 8-20 months (mean, 14.3 months). During operation, the internal implant was removed; infection and necrotic tissue was removed thoroughly; and the Ilizarov external fixator was installed. After operation, gentamycin normal saline was used for 2 to 3 weeks, and the sensitive antibiotic intravenous infusion was performed at the same time. After 1 week, the osteotomy lengthening was used. RESULTS: All 6 patients were followed up for 6 to 18 months (mean, 12.2 months). Pin tract infection occurred in 1 case after operation; primary healing of incision was obtained in the other patients, and no related complications occurred. The external fixation time ranged from 6 to 16 months (mean, 11.5 months). The healing indexes ranged from 34 to 62 days/cm (mean, 52.0 days/cm). After removal of the external fixator, the knee range of motion ranged from 0 to 5° (mean, 3°) in extension, and from 120 to 130° (mean, 125°) in flexion. The American musculo-skeletal tumor society system (MSTS) function scoring was excellent in 3 patients, good in 2 patients, and fair in 1 patient, with an excellent and good rate of 83.3%. During follow-up period, there was no recurrence of infection; and no recurrence or metastasis was found in 3 patients with osteosarcoma. CONCLUSIONS: Infection can be cured by Ilizarov technique after limb salvage operation of bone tumor.


Assuntos
Neoplasias Ósseas/cirurgia , Técnica de Ilizarov , Salvamento de Membro , Adolescente , Adulto , Feminino , Humanos , Masculino , Recidiva Local de Neoplasia , Estudos Retrospectivos , Tíbia , Resultado do Tratamento , Adulto Jovem
20.
Zhongguo Gu Shang ; 28(7): 617-21, 2015 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-26399103

RESUMO

OBJECTIVE: To radiographically analyze the osseous fixation zone for the iliac crest external fixation with Schanz screws and in order to guide their placement. METHODS: Nine adults with 2.0-mm-slice continuous pelvic axial CT scans were selected as research subjects. Each CT scan data was imported into MIMICS 10.0. The osseous fixation zone the upper portion of the anterior column of the acetabulum which is located between the anterior superior iliac spine and the gluteal medius pillar and between the iliac crest and the acetabulum-for the iliac crest external fixation with Schanz screws was reconstructed into true sagittal and true coronal planes by using the software. Then the measurements were taken on the reconstructed planes with measuring tools. Finally, the measured data was analyzed. RESULTS: The palpable iliac crest segment, which was of 49.6 mm width and located 16.5 mm posterior to the anterior superior iliac spine could be used to locate the start points of the Schanz screws. Under the above-mentioned iliac crest segment, the osseous zone was deep, got ample bony materials and could intraosseously contain Schanz screws with 5.0 mm diameter. The screws could be safely inserted to a minimal depth of 71.7 mm towards the acetabular dome and to a maximal depth of 143.5 mm posterior to the acetabulum. CONCLUSION: The study can guide the effective insertion of the iliac crest Schanz screws. By setting a suitable start point in the above-mentioned iliac crest region and angling correctly relative to the acetabulum,the Schanz screw can be inserted into the relative strong cancellous bone above or posterior to the acetabulum with a considerable depth, to getting more bone engagement.


Assuntos
Fraturas Ósseas/cirurgia , Ílio/cirurgia , Adulto , Idoso , Parafusos Ósseos , Feminino , Fixação de Fratura , Fraturas Ósseas/diagnóstico por imagem , Humanos , Ílio/diagnóstico por imagem , Ílio/lesões , Masculino , Pessoa de Meia-Idade , Procedimentos Ortopédicos , Tomografia Computadorizada por Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA