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1.
Opt Express ; 27(15): 20763-20773, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31510165

RESUMO

In this paper, a highly-sensitive distributed shape sensor based on a multicore fiber (MCF) and phase-sensitive optical time-domain reflectometry (φ-OTDR) is proposed and experimentally demonstrated. The implemented system features a high strain sensitivity (down to ∼0.3 µÉ›) over a 24 m-long MCF with a spatial resolution of 10 cm. The results demonstrate good repeatability of the relative fiber curvature and bend orientation measurements. Changes in the fiber shape are successfully retrieved, showing detectable displacements of the free moving fiber end as small as 50 µm over a 60 cm-long fiber. In addition, the proposed technique overcomes cross-sensitivity issues between strain and temperature. To the best of our knowledge, the results presented in this work provide the first demonstration of distributed shape sensing based on φ-OTDR using MCFs. This high-sensitivity technique proves to be a promising approach for a wide range of new applications such as dynamic, long distance and three-dimensional distributed shape sensing.

2.
Opt Lett ; 43(19): 4574-4577, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30272686

RESUMO

Different approaches to implement unipolar Golay coding in Brillouin optical time-domain analysis based on a differential pulse pair (DPP) are investigated. The analysis points out that dedicated post-processing procedures must be followed to secure the sharp spatial resolution associated with the DPP method. Moreover, a novel hybrid Golay-DPP coding scheme is proposed, offering 1.5 dB signal-to-noise ratio improvement with respect to traditional unipolar Golay coding, while halving the measurement time, constituting a 3 dB overall coding gain enhancement. Proof-of-concept experiments validate the proposed technique, demonstrating a 50 cm spatial resolution over a 10.164 km long sensing fiber with a frequency uncertainty of 1.4 MHz.

3.
Nat Commun ; 9(1): 2990, 2018 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-30065245

RESUMO

The distributed fibre sensing technology based on backward stimulated Brillouin scattering (BSBS) is experiencing a rapid development. However, all reported implementations of distributed Brillouin fibre sensors until today are restricted to detecting physical parameters inside the fibre core. On the contrary, forward stimulated Brillouin scattering (FSBS), due to its resonating transverse acoustic waves, is being studied recently to facilitate innovative detections in the fibre surroundings, opening sensing domains that are impossible with BSBS. Nevertheless, due to the co-propagating behaviour of the pump and scattered lights, it is a challenge to position-resolve FSBS information along a fibre. Here we show a distributed FSBS analysis based on recovering the FSBS induced phase change of the propagating light waves. A spatial resolution of 15 m is achieved over a length of 730 m and the local acoustic impedances of water and ethanol in a 30 m-long uncoated fibre segment are measured, agreeing well with the standard values.

4.
Opt Express ; 26(13): 16505-16523, 2018 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-30119480

RESUMO

The performance of unipolar unicolor coded Brillouin optical time-domain analysis (BOTDA) is evaluated based on both Simplex and Golay codes. Four major detrimental factors that limit the system performance, including decoded-gain trace distortion, coding pulse power non-uniformity, polarization pulling and higher-order non-local effects, are thoroughly investigated. Through theoretical analysis and an experimental validations, solutions and optimal design conditions for unipolar unicolor coded BOTDA are clearly established. First, a logarithmic normalization approach is proposed to resolve the linear accumulated Brillouin amplification without distortion. Then it is found out that Simplex codes are more robust to pulse power non-uniformity compared to Golay codes; whilst the use of a polarization scrambler must be preferred in comparison to a polarization switch to mitigate uncompensated fading induced by polarization pulling in the decoded traces. These optimal conditions enables the sensing performance only limited by higher-order non-local effects. To secure systematic errors below 1.3 MHz on the Brillouin frequency estimation, while simultaneously reaching the maximum signal-to-noise ratio (SNR), a mathematical model is established to trade-off the key parameters in the design, i.e., the single-pulse Brillouin amplification, code length and probe power. It turns out that the optimal SNR performance depends in inverse proportion on the value of maximum single-pulse Brillouin amplification, which is ultimately determined by the spatial resolution. The analysis here presented is expected to serve as a quantitative guideline to design a distortion-free coded BOTDA system operating at maximum SNR.

5.
Opt Express ; 26(11): 14661-14677, 2018 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-29877403

RESUMO

The performance of post-processing techniques carried out on the Brillouin gain spectrum to estimate the Brillouin frequency shift (BFS) in standard Brillouin distributed sensors is evaluated. Curve fitting methods with standard functions such as polynomial and Lorentzian, as well as correlation techniques such as Lorentzian Cross-correlation and Cross Reference Plot Analysis (CRPA), are considered for the analysis. The fitting procedures and key parameters for each technique are optimized, and the performance in terms of BFS uncertainty, BFS offset error and processing time is compared by numerical simulations and through controlled experiments. Such a quantitative comparison is performed in varying conditions including signal-to-noise ratio (SNR), frequency measurement step, and BGS truncation. It is demonstrated that the Lorentzian cross-correlation technique results in the largest BFS offset error due to truncation, while exhibiting the smallest BFS uncertainty and the shortest processing time. A novel approach is proposed to compensate such a BFS offset error, which enables the Lorentzian cross-correlation technique to completely outperform other fitting methods.

6.
Int J Mol Med ; 42(2): 1199, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29749426

RESUMO

Subsequently to the publication of this article, the authors have realized that an address affiliation associated with certain of the authors had been omitted. The authors' affiliation information should have appeared as follows (the omitted address affiliation is featured in bold): Yi­Ying Yang1,2*, Xiu­Ting Sun1,2*, Zheng­Xun Li1,2, Wei­Yan Chen3, Xiang Wang4, Mei­Ling Liang5, Hui Shi1,2, Zhi­Sheng Yang1,2 and Wu­Tao Zeng1,2 1Department of Cardiology, The First Affiliated Hospital, Sun Yat­Sen University; 2Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou, Guangdong 510080; 3Intensive Care Unit, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510260; 4Department of Cardiology, Laiwu City People's Hospital, Laiwu, Shandong 27110; 5Department of Cardiology, Sun Yat­Sen Cardiovascular Hospital, Shenzhen, Guangdong 518020, P.R. China *Contributed equally. The authors regret this error in the affiliations, and apologize for any inconvenience caused. [the original article was published in the International Journal of Molecular Medicine 41: 1283­1292, 2018; DOI: 10.3892/ijmm.2017.3322].

7.
Int J Mol Med ; 41(3): 1283-1292, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29286068

RESUMO

Angiotensin-(1-7) [Ang-(1-7)], a heptapeptide mainly generated from cleavage of AngⅠ and AngⅡ, possesses physiological and pharmacological properties, including anti­inflammatory and antidiabetic properties. Activation of the phosphoinositide 3-kinase and protein kinase B (PI3K̸Akt) signaling pathway has been confirmed to participate in cardioprotection against hyperglycaemia-induced injury. The aim of the present study was to test the hypothesis that Ang-(1-7) protects H9c2 cardiomyoblast cells against high glucose (HG)-induced injury by activating the PI3K̸Akt pathway. To examine this hypothesis, H9c2 cells were treated with 35 mmol/l (mM) glucose (HG) for 24 h to establish a HG-induced cardiomyocyte injury model. The cells were co-treated with 1 µmol/l (µM) Ang-(1-7) and 35 mM glucose. The findings of the present study demonstrated that exposure of H9c2 cells to HG for 24 h markedly induced injury, as evidenced by an increase in the percentage of apoptotic cells, generation of reactive oxygen species and level of inflammatory cytokines, as well as a decline in cell viability and mitochondrial luminosity. These injuries were significantly attenuated by co-treatment of the cells with Ang-(1-7) and HG. In addition, PI3K̸Akt phosphorylation was suppressed by HG treatment, but this effect was abolished when the H9c2 cells were co-treated with Ang-(1-7) and HG. Furthermore, the cardioprotection of Ang-(1-7) against HG-induced injury in H9c2 cardiomyoblasts was highly attenuated in the presence of either D-Ala7-Ang-(1-7) (A-779, an antagonist of the Mas receptor) or LY294002 (an inhibitor of PI3K̸Akt). In conclusion, the present study provided new evidence that Ang-(1-7) protects H9c2 cardiomyoblasts against HG-induced injury by activating the PI3K̸Akt signaling pathway.


Assuntos
Angiotensina I/farmacologia , Cardiotônicos/farmacologia , Hiperglicemia/patologia , Miócitos Cardíacos/enzimologia , Miócitos Cardíacos/patologia , Fragmentos de Peptídeos/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Citoproteção/efeitos dos fármacos , Glucose/toxicidade , Inflamação/patologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Ratos , Espécies Reativas de Oxigênio/metabolismo
8.
Mol Med Rep ; 17(1): 1461-1468, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29257199

RESUMO

The transplantation of mesenchymal stem cells (MSCs) has been a reported method for alleviating atherosclerosis (AS). Because the availability of bone marrow­derived MSCs (BM­MSCs) is limited, the authors used this study to explore the use of a new type of MSC, human induced pluripotent stem cell­derived MSCs (iPSC­MSCs), to evaluate whether these cells could alleviate AS. iPSC­MSCs were intravenously administered to ApoE knock out mice fed on a high­fat diet (HFD) for 12 weeks. It was reported that systematically administering iPSC­MSCs clearly reduced the size of plaques. In addition, the numbers of macrophages and lipids in plaques were lower in the HFD + iPSC­MSCs group than in the HFD group. Furthermore, iPSC­MSCs attenuated AS­associated inflammation by decreasing the levels of inflammatory cytokines, such as tumor necrosis factor­α and interleukin­6, in serum. In addition, the expression of Notch1 was higher in the HFD group, and injecting iPSC­MSCs reversed this effect. In conclusion, the current study provides the first evidence indicating that iPSC­MSCs may be a new optional MSC­based strategy for treating AS.


Assuntos
Aterosclerose/terapia , Células-Tronco Pluripotentes Induzidas/citologia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/citologia , Animais , Aterosclerose/sangue , Aterosclerose/complicações , Aterosclerose/imunologia , Células Cultivadas , Citocinas/sangue , Citocinas/imunologia , Humanos , Células-Tronco Pluripotentes Induzidas/imunologia , Inflamação/sangue , Inflamação/complicações , Inflamação/imunologia , Inflamação/terapia , Masculino , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/imunologia , Camundongos , Camundongos Endogâmicos C57BL
9.
Opt Express ; 25(7): 7604-7615, 2017 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-28380880

RESUMO

This paper proposes a novel method based on differential π-phase-shift long-pulse-width pair to narrow the Brillouin gain spectrum for improving the frequency accuracy in Brillouin optical time-domain analysis (BOTDA) system. This is the first approach to reduce the bandwidth of Brillouin gain spectrum for distributed sensing to the best of our knowledge. The temporal and spectral Brillouin responses for the proposal are analytically solved, and the key parameters such as pulse width and the length of π-phase-shift pulse section are investigated. Theoretical analysis and experimental results demonstrate that the proposal could achieve 17 MHz Brillouin gain spectrum bandwidth and a fixed spatial resolution of 2.5 m simultaneously, without signal-to-noise ratio penalty. This Brillouin gain spectrum is 3 times narrower than that obtained using standard single-pulse based BOTDA method with same spatial resolution, resulting in3times frequency accuracy improvement. Furthermore, such a significantly narrowed Brillouin gain spectrum provides more tolerance to the small temperature change when hot spots are introduced, giving rise to the sharper rising/falling edge of the Brillouin frequency shift profile along the sensing fiber. This way, more precise temperature/strain measurement can be obtained.

10.
Opt Express ; 24(18): 21046-58, 2016 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-27607708

RESUMO

The tolerance of the non-local effect in the BOTDA method using a dual-tone probe wave with fixed frequency separation is theoretically and experimentally investigated in this paper. The presented analysis points out that when the sensing fiber consists of two long fiber segments with large BFS difference (> 100 MHz), there will always be only one probe tone interacting with the pump pulse in the front fiber segment. Therefore, although the pulse distortion problem can still be overcome in this case, the conventional non-local effect would impose systematic error on the estimated BFS of the hotspot located at the end of the front fiber segment. For the purpose of avoiding the impact of non-local effect and eliminating the pump distortion problem simultaneously when using high probe power, a novel method based on a four-tone probe wave is proposed, in which the probe light consists of two pairs of orthogonally-polarized dual-tone probe waves with opposite frequency scanning direction. The experimental results demonstrate that the proposed method is capable of realizing 2 m spatial resolution over 104-km-long sensing fiber without the impact of non-local effect.

11.
Eur J Clin Pharmacol ; 72(11): 1327-1334, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27488389

RESUMO

PURPOSE: The aim of this study was to investigate whether any of the single-nucleotide polymorphisms (SNPs) in the POR gene were significantly associated with CYP activity and expression, and could contribute to the total variability in stable warfarin maintenance doses in Han Chinese. METHODS: A total of 408 patients treated at the First Affiliated Hospital of Sun Yat-Sen University were eligible for the study and had attained a stable warfarin maintenance dose at the start of the investigation. Demographics, warfarin maintenance doses, and concomitant medications were documented. Genomic DNA was extracted from peripheral blood samples and genotyped for ten SNPs (CYP 2C9*2 and *3, CYP4F2 rs2108622, VKORC1 -1639C>T, and potential POR genes of rs10239977, rs3815455, rs41301394, rs56256515, rs1057868, and rs2286823) using the Sequenom MassARRAY genotyping system. RESULTS: A predictive model of warfarin maintenance dose was established and indicated that age, gender, body surface area, aspirin use, CYP2C9*3, CYP4F2 rs2108622, VKORC1 -1639C>T, and POR*37 831-35C>T accounted for 42.4 % of dose variance in patients undergoing anticoagulant treatment. The contribution of POR*37 831-35C>T to warfarin dose variation was only 3.9 %. CONCLUSIONS: For the first time, the SNP POR*37 831-35C>T was confirmed as a minor but statistically significant factor associated with interindividual variation in warfarin maintenance dose in Han Chinese. The POR*37 gene polymorphism should be considered in future algorithms for faster and more reliable achievement of stable warfarin maintenance doses.


Assuntos
Anticoagulantes/administração & dosagem , Grupo com Ancestrais do Continente Asiático/genética , Sistema Enzimático do Citocromo P-450/genética , Modelos Biológicos , Varfarina/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/uso terapêutico , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Varfarina/uso terapêutico , Adulto Jovem
12.
Opt Express ; 24(10): 10188-204, 2016 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-27409845

RESUMO

Systematic errors induced by distortions in the pump pulse of conventional Brillouin distributed fiber sensors are thoroughly investigated. Experimental results, supported by a theoretical analysis, demonstrate that the two probe sidebands in standard Brillouin optical time-domain analyzers provide a non-zero net gain on the pump pulse, inducing severe distortions of the pump when scanning the pump-probe frequency offset, especially at high probe power levels. Compared to the impact of non-local effects reported in the state-of-the-art, measurements here indicate that for probe powers in the mW range (below the onset of amplified spontaneous Brillouin scattering), the obtained gain and loss spectra show two strong side-lobes that lead to significant strain/temperature errors. This phenomenon is not related to the well-known spectral hole burning resulting from pump depletion, but it is strictly related to the temporal and spectral distortions that the pump pulse experiences when scanning the Brillouin gain/loss spectrum. As a solution to this problem, a novel scanning scheme for Brillouin sensing is proposed. The method relies on a fixed frequency separation between the two probe sidebands, so that a flat zero net gain is achieved on the pump pulse when scanning the pump-probe frequency offset. The proposed technique is experimentally validated, demonstrating its ability to completely cancel out non-local effects up to a probe power ultimately limited by the onset of amplified spontaneous Brillouin scattering. The method allows for one order of magnitude improvement in the figure-of-merit of optimized long-range Brillouin distributed fiber sensors, enabling measurements along a 100 km-long sensing fiber with 2 m spatial resolution and with no need of added features for performance enhancement.

13.
Opt Express ; 24(1): 586-97, 2016 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-26832289

RESUMO

The robustness of bipolar pulse coding against pump depletion issues in Brillouin distributed fiber sensors is theoretically and experimentally investigated. The presented analysis points out that the effectiveness of bipolar coding in Brillouin sensing can be highly affected by the power unbalance between -1's and + 1's elements resulting from depletion and amplification of coded pump pulses. In order to increase robustness against those detrimental effects and to alleviate the probe power limitation imposed by pump depletion, a technique using a three-tone probe is proposed. Experimental results demonstrate that this method allows increasing the probe power by more than 12.5 dB when compared to the existing single-probe tone implementation. This huge power increment, together with the 13.5 dB signal-to-noise enhancement provided by 512-bit bipolar Golay codes, has led to low-uncertainty measurements (< 0.9 MHz) of the local Brillouin peak gain frequency over a real remoteness of 100 km, using a 200 km-long fiber-loop and 2 m spatial resolution. The method is evaluated with a record figure-of-merit of 380'000.

14.
Opt Express ; 24(2): 1543-58, 2016 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-26832533

RESUMO

The detrimental impact of the second echo phenomenon that commonly exists in Brillouin echoes distributed sensing (BEDS) methods is thoroughly investigated by further developing the analytical model of the Brillouin gain on the probe wave. The presented analysis not only points out that the most severe impact imposed by the second echo occurs when the length of the heated/stressed fiber section is exactly equal to the spatial resolution, but also quantifies the systematic error on the estimated Brillouin frequency shift, the maximum of which could reach up to 8.5 MHz. A novel parabolic-amplitude four-section pulse is proposed, which can compensate the impact of the second echo optically, without using extra measurement time and post-processing. The key parameters of the proposed pulse are optimized by combining an upgraded mathematical model and the iterative algorithm. The experimental results show a good agreement with the analysis about the behavior of the second echo, and demonstrate that the proposed technique is capable of providing sub-meter spatial resolution and the natural linewidth of Brillouin gain spectrum simultaneously, while completely eliminating the impact of the second echo.

15.
Opt Express ; 22(3): 2881-8, 2014 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-24663580

RESUMO

We propose and demonstrate a distributed Brillouin fiber sensor using Stokes and anti-Stokes differential pulse pair based on double- sideband probe wave, in which the two sidebands of probe wave are used to balance the power of two pump pulses. The spatial resolution is determined by the slightly width difference of the two balanced pulses, without Brillouin gain spectrum broadening. The pulses perform gain-loss process in optical field before the probe signal being detected, without any post-processing or extra measurement time. The proposed technique can achieve high spatial resolution, natural Brillouin gain spectrum linewidth, normal measurement time and long sensing range simultaneously.

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