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1.
Opt Express ; 27(15): 21896-21913, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31510258

RESUMO

Polarization demultiplexing is generally carried out by a multiple-input multiple-output (MIMO) based algorithm in polarization division multiplexing (PDM) coherent systems. However, in some extreme environments, the MIMO algorithm becomes inapplicable due to the ultra-fast rotation of the state of polarization (RSOP) and large polarization mode dispersion (PMD). In addition, the residual chromatic dispersion (RCD) is always present because of the mismatch of the compensated chromatic dispersion and real value induced in the optical fiber channel. According to the literature, the Kalman filter-based polarization demultiplexing algorithms possess very weak RCD tolerance. Faced with this dilemma, in this paper, a new Kalman filter structure is proposed, which can jointly compensate ultra-fast RSOP, large PMD and RCD. This Kalman filter structure enables the equalization of the RSOP in the time domain and compensation for RCD and PMD in the frequency domain. We verified the performance of the proposed Kalman scheme in the 28 Gbaud PDM-QPSK/16 QAM coherent system, with a comparison to constant modulus algorithm/multiple modulus algorithm (CMA/MMA). The simulation results confirm that, compared with CMA/MMA, the proposed Kalman scheme can provide a significant performance enhancement to cope with ultra-fast RSOP (up to 3 Mrad/s) and large PMD (more than 200 ps) with a large tolerance to RCD (over the range of ± 820 ps/nm in PDM-QPSK and ± 500 ps/nm in PDM-16 QAM).

2.
Opt Lett ; 44(12): 2994-2997, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31199364

RESUMO

A novel all-fiber broadband mode multiplexer based on an elliptical ring core fiber structure mode selective coupler (MSC) is proposed and analyzed numerically. The MSC is composed of a core-doped single-mode fiber and a polarization-maintaining elliptical ring-shaped core few-mode fiber (FMF). The mode multiplexing can be implemented by a single LP01 mode excitation that does not introduce insertion loss, which can simplify and promote the multiplexer. The high refractive index difference between the elliptical annular region and the cladding of the FMF, as well as the ellipticity of the ring-shaped core of the FMF could not only decompose the degenerate modes, but also reduce the mode coupling of the adjacent spatial modes to eliminate the multiple-input-multiple-output digital-signal processing in the receiver of the mode division multiplexing system. Finally, a seven-mode multiplexer is modeled and optimized for operation covering the C+L band. Furthermore, the multiplexer provides a high coupling efficiency (>64% for the worst case) for the seven spatial modes, LP01, LP11a, LP11b, LP21a, LP21b, LP31a, and LP31b, and relatively high mode extinction ratios of more than 15 dB in the C-band.

3.
Mol Ther ; 27(7): 1327-1338, 2019 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-31129118

RESUMO

Primary open-angle glaucoma (POAG) is considered a lifelong disease characterized by optic nerve deterioration and visual field damage. Although the disease progression can usually be controlled by lowering the intraocular pressure (IOP), therapeutic effects of current approaches do not last long. Gene therapy could be a promising method for persistent treatment of the disease. Our previous study demonstrated that gene transfer of exoenzyme C3 transferase (C3) to the trabecular meshwork (TM) to inhibit Rho GTPase (Rho), the upstream signal molecule of Rho-associated kinase (ROCK), resulted in lowered IOP in normal rodent eyes. In the present study, we show that the lentiviral vector (LV)-mediated C3 expression inactivates RhoA in human TM cells by ADP ribosylation, resulting in disruption of the actin cytoskeleton and altered cell morphology. In addition, intracameral delivery of the C3 vector to monkey eyes leads to persistently lowered IOP without obvious signs of inflammation. This is the first report of using a vector to transduce the TM of an alive non-human primate with a gene that alters cellular machinery and physiology. Our results in non-human primates support that LV-mediated C3 expression in the TM may have therapeutic potential for glaucoma, the leading cause of irreversible blindness in humans.

4.
Opt Express ; 27(8): 11557-11570, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31052999

RESUMO

We propose a joint blind equalization method for chromatic dispersion (CD) and ultra-fast rotation of state-of-polarization (RSOP) in a Stokes vector direct detection (SV-DD) system based on a new time-frequency domain Kalman filter structure. In an SV-DD system, the impairments induced by CD and RSOP possess a nonlinear form. Therefore, CD and RSOP cannot be treated sequentially, which causes difficulty in jointly equalizing these two impairments using an ordinary algorithm. The Kalman filter was proven to be effective in equalizing polarization effects in a coherent receiver. However, this approach has inherent limitations given that the Kalman filter was originally presented as a method implemented in the time domain whereas CD is eventually induced in the frequency domain. In this report, the proposed time-frequency domain Kalman filter can facilitate CD compensation in the frequency domain and RSOP equalization in the time domain by exploiting a sliding window structure. Both the CD compensation and the RSOP equalization are conducted in Stokes space when the proposed method is utilized, which is specially designed for an SV-DD system. The presented approach was checked using a 28 Gbaud 16-QAM SV-DD system simulation platform. The simulation results confirm that the method is very effective and has strong tolerance to CD (more than 2550 ps/nm, equivalent to a 150 km G. 652 fiber) combined with ultra-fast RSOP (up to 2 Mrad/s) for application in extreme polarization environments, like the transient lightning in a rainy day.

5.
BMJ Open ; 9(5): e028595, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31123001

RESUMO

INTRODUCTION: Antiplatelet therapy combining aspirin and clopidogrel is considered to be a key intervention for acute ischaemic minor stroke (AIMS) and transient ischaemic attack (TIA). However, the interindividual variability in response to clopidogrel resulting from the polymorphisms in clopidogrel metabolism-related genes has greatly limited its efficacy. To date, there are no reports on individualised antiplatelet therapy for AIMS and TIA based on the genetic testing and clinical features. Therefore, we conduct this randomised controlled trial to validate the hypothesis that the individualised antiplatelet therapy selected on the basis of a combination of genetic information and clinical features would lead to better clinical outcomes compared with the standard care based only on clinical features in patients with AIMS or TIA. METHODS AND ANALYSIS: This trial will recruit 2382 patients with AIMS or TIA who meet eligibility criteria. Patients are randomly assigned in a 1:1 ratio to pharmacogenetic group and standard group. Both groups receive a loading dose of 300 mg aspirin and 300 mg clopidogrel on day 1, followed by 100 mg aspirin per day on days 2-365. The P2Y12 receptor antagonist is selected by the clinician according to the genetic information and clinical features for pharmacogenetic group and clinical features for the standard group on days 2-21. The primary efficacy endpoint is a new stroke event (ischaemic or haemorrhagic) that happens within 1 year. The secondary efficacy endpoint is analysed as the individual or composite outcomes of the new clinical vascular event (ischaemic stroke, haemorrhagic stroke, myocardial infarction or vascular death). Baseline characteristics and outcomes after treatment will be evaluated. ETHICS AND DISSEMINATION: This protocol has been approved by the ethics committee of Yangpu Hospital, Tongji University School of Medicine (No. LL-2018-KY-012). We will submit the results of this trial for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ChiCTR1800019911; Pre-results.

6.
Sci Rep ; 9(1): 5067, 2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30911024

RESUMO

To achieve the best high spectral quantitative inversion of salt-affected soils, typical saline-sodic soil was selected from northeast China, and the soil spectra were measured; then, partial least-squares regression (PLSR) models and principle component regression(PCR) models were established for soil spectral reflectance and soil salinity, respectively. Modelling accuracies were compared between two models and conducted with different spectrum processing methods and different sampling intervals. Models based on all of the original spectral bands showed that the PLSR was superior to the PCR; however, after smoothing the spectra data, the PLSR did not continue outperforming the PCR. Models established by various transformed spectra after smoothing did not continue showing superiority of the PCR over the PLSR; therefore, we can conclude that the prediction accuracies of the models were not only determined by the smoothing methods, but also by spectral mathematical transformations. The best model was the PCR based on the median filtering data smoothing technique (MF) + log (1/X) + baseline correction transformation (R2 = 0.7206 and RMSE = 0.3929). To keep the information loss becoming too large, this suggested that an 8 nm sampling interval was the best when using soil spectra to predict soil salinity for both the PLSR and PCR models.

7.
Biomed Res Int ; 2019: 3080827, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30881985

RESUMO

Background: Urosepsis and septic shock are a critical situation leading to a mortality rate up to 30% in patients with obstructive diseases of the urinary tract. Aim: To analyze the bacterial distribution and drug resistance of pathogenic bacteria in patients with urosepsis and to provide a basis for the rational application of antibacterial drugs in clinical practice. Methods: A retrospective analysis of 94 hospitalized patients with urosepsis for 6 years was performed. The strain composition, resistance characteristics, and the antibiogram of common bacteria from positive blood and midstream urine culture were analyzed. Results: A total of 87 strains were isolated, including 65 strains (74.71%) of Gram-negative bacilli, 14 strains (16.09%) of Gram-positive cocci, and 8 strains (9.20%) of fungi. The Gram-negative bacilli included 42 strains of Escherichia coli (E. coli) (64.62%), among which 34 strains (80.95%) were producing ESBLs, and 14 strains (21.84%) of Klebsiella pneumoniae (K. pneumoniae), among which nine strains (64.29%) were producing ESBLs. The most common pathogenic bacteria, ESBL+ E. coli and K. pneumoniae strains, showed sensitivity towards imipenem, ertapenem, piperacillin/tazobactam, amikacin, and cefotetan, but were highly resistant to quinolones. The cure rate of urosepsis was 88.30%, and the susceptibility rate of septic shock was 45.47%. Significance: Gram-negative bacterial infections are the main cause of urosepsis. The mild patient group showed more E. coli (ESBL-) infections, and the number of ESBL producing E. coli isolated from the mild group showed higher drug resistance rates for aztreonam and levofloxacin compared with isolates from the severe group.


Assuntos
Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Sepse/tratamento farmacológico , Choque Séptico/tratamento farmacológico , Infecções Urinárias/tratamento farmacológico , Ertapenem/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/patogenicidade , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/patologia , Humanos , Imipenem/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Quinolonas/farmacologia , Sepse/microbiologia , Sepse/patologia , Choque Séptico/microbiologia , Choque Séptico/patologia , Infecções Urinárias/microbiologia , Infecções Urinárias/patologia
8.
Sensors (Basel) ; 19(2)2019 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-30669337

RESUMO

Real-time monitoring of wire rope tension is of great significance to the safe operation of mine hoist. Due to the longitudinal and lateral coupling vibration of wire ropes during the operation of hoist, there are high frequency components in measured tension signals of wire ropes, which cannot effectively characterize the actual lifting load. To overcome this problem, a particle damping sensor with a vibration dissipation function is designed in this paper. Multilayered steel balls are placed into the cylindrical cavity of the sensor. Damping vibration and energy dissipation will occur when the sensor is subjected to external excitation. Then, to obtain the optimal sensor characteristics, relevant parameters of the particles and the spoke structure are simulated. Finally, the sensor based on the optimized parameters is manufactured and tested in a coal mine. Compared with the general pressure sensor, the particle damping sensor can effectively eliminate the influence of wire ropes vibration on tension measurement and achieve accurate measurement results.

9.
Opt Express ; 26(18): 23507-23517, 2018 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-30184850

RESUMO

A lightweight convolutional (deep) neural networks (CNNs) based modulation format identification (MFI) scheme in 2D Stokes planes for polarization domain multiplexing (PDM) fiber communication system is proposed and demonstrated. Influences of the learning rate of CNN is discussed. Experimental verifications are performed for the PDM system at a symbol rate of 28GBaud. Six modulation formats are identified with a trained CNN from images of received signals. They are PDM-BPSK, PDM-QPSK, PDM-8PSK, PDM-16QAM, PDM-32QAM, and PDM-64QAM. By taking advantage of computer vision, the results show that the proposed scheme can significantly improve the identification performance over the existing techniques.

10.
Sensors (Basel) ; 18(9)2018 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-30200248

RESUMO

The real-time tension monitoring of wire ropes is a universal way to judge whether the hoist is overloaded in the special working environment of the coal mine. However, due to the strong drafts, unevenness of guide and flexible vibration of wire ropes, it is a challenge to monitor the tension with high accuracy. For this purpose, a new type of acoustic filtering sensor is designed in this study. To adapt to the violent vibration during the monitoring process, a structure with a cylindrical cavity and a narrow gap is designed in the sensor. The coupling between the internal fluid and sensor structure can greatly absorb the vibration energy. With the view of optimizing the filtering performance of the sensor, the influences on the filtering characteristics are presented and analyzed through employing different structural and acoustic parameters in simulations. Finally, acoustic filtering sensor prototypes based on optimized parameters are calibrated and tested in a real coal mine. The results have revealed that our acoustic filtering sensor can not only address the deficiencies of current pressure sensors in coal mining and achieve tension monitoring in real-time, but is also able to diagnose and forecast the occurrence of tension imbalance accidents.

11.
Zhongguo Gu Shang ; 31(7): 604-607, 2018 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-30103581

RESUMO

OBJECTIVE: To investigate clinical effects of calcaneal fracture with closed reduction and minimally invasive plate fixation assisted with bidirectional distractor distraction. METHODS: From September 2015 to October 2016, 11 male patients(13 feet) with calcaneal fractures treated with bidirectional distractor distraction assisted with minimally invasive plate fixation were retrospectively studied. They were aged from 24 to 57 years old with an average of 36.4 years old;8 feet were type IIand 5 feet were type III according to Sanders classification. Postoperative incision, fracture healing, Böhler angle, Gissane angle were observed and Maryland scoring system was used to evaluate clinical effects. RESULTS: All fractures healed well without incision inflammation and incision disunion. All patients were followed up from 12 to 15 months with an average of 13.5 months. Böhler angle were improved from (9.6±7.3)° before operation to (20.2±4.6) ° at 1 year after operation, and had statistical meaning; Gissane angle increased from (92.7 ±8.5)° before operation to (121.7 ±7.6) ° at 1 year after operation. Maryland score at 1 year after operation was 88.79±8.25, and 11 feet got excellent results and 2 feet moderate. CONCLUSIONS: Bidirectional distractor distraction assisted with minimally invasive plate fixation could effectively fix calcaneal fractures, reduce postoperative complications, and get satisfied results of postoperative images and functional recovery. It is one of effective methods for treating Sanders II and III calcaneal fractures.

12.
Opt Express ; 26(16): 21170-21183, 2018 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-30119421

RESUMO

In this paper, we highlight that it is inadequate to describe the rotation of the state of polarization (RSOP) in a fiber channel with the 2-parameter description model, which was mostly used in the literature. This inadequate model may result in problems in polarization demultiplexing (PolDemux) because the RSOP in a fiber channel is actually a 3-parameter issue that will influence the state of polarization (SOP) of the optical signal propagating in the fiber and is different from the 2-parameter SOP itself. Considering three examples of the 2-parameter RSOP models typically used in the literature, we provide an in-depth analysis of the reasons why the 2-parameter RSOP model cannot represent the RSOP in the fiber channel and the problems that arise for PolDemux in the coherent optical receiver. We present a 3-parameter solution for the RSOP in the fiber channel. Based on this solution, we propose a DSP tracking and equalization scheme for the fast time-varying RSOP using the extended Kalman filter (EKF). The proposed scheme is proved to be universal and can solve all the PolDemux problems based on the 2- or 3-parameter RSOP model and exhibits good performance in the time-varying RSOP scenarios.

13.
Cancer Med ; 7(8): 3763-3772, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30022623

RESUMO

CD164 was found to play a role in many malignant diseases. But the roles of CD164 in human bladder cancer have not yet been studied. The object of our study was to investigate the functions of CD164 in urothelial bladder carcinoma. The immunohistochemistry (IHC) was performed to evaluate the associations between the expression level of CD164 and clinical-pathological features of patients, and IHC was used to analyze the relationship between CD164 and CXCR4 in tumor tissues. Real-time qPCR and Western blot were used to measure the expression of relevant genes. The roles of CD164 in tumor cells and tissues were investigated by in vitro and in vivo experiments. The results of immunohistochemistry found that CD164 was associated with clinical and pathological features of patients. High level of CD164 was related to the distant metastasis and vascular invasion of bladder cancer patients. In vitro, by silencing of CD164, the proliferation, migration, and invasion of tumor cells were inhibited significantly by regulating related proteins such as Ki67, proliferating cell nuclear antigen, matrix metalloproteinases-2, and matrix metalloproteinases-9. In vivo, knocking-down of CD164 could reduce the growth and metastasis of tumors in mice. In addition, a co-expression was found between CD164 and CXCR4 in tumor tissues. In conclusion, our study demonstrated that CD164 was associated with the poor clinical outcomes of BC patients. Silencing of CD164 could inhibit the progression of tumors in vivo and in vitro, which may become an effective target in the treatment of bladder cancer.

14.
J Pharm Biomed Anal ; 159: 11-17, 2018 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-29960039

RESUMO

Paraquat is an effective herbicide chemical but a highly toxic compound for humans and animals. The measurement of paraquat concentration in blood is important to clinic or forensic practice. Herein, a method has been developed for the analysis of paraquat in human blood using dried blood spot (DBS) extraction and subsequent UHPLC-HRMS analysis. Three droplets (100 µL each) of blood were spotted on the Whatman® FTA classic card and then let dry by microwave irradiation (1200 W) for 5 min to prepare DBS. An 8 mm diameter punch was removed from the center of DBS and extracted with 190 µL of mobile phase (20 mM ammonium acetate with 0.1% formic acid and 5% acetonitrile in ultra-pure water) and 10 µL of internal standard (paraquat-d8, 100 ng/mL). After ultrasonic treatment for 10 min, the tube was centrifuged, and the supernatant was then filtered by 0.2 µm membrane and injected into the UHPLC-HRMS system. The method was validated considering the following parameters: selectivity, LOD and LLOQ, linearity, precision, accuracy. The method showed satisfactory linearity in the range of 1-1000 ng/mL, with high determination coefficient (0.9986). LOD was 0.5 ng/mL, and LLOQ was 1 ng/mL. Selectivity, intra and inter day precision and accuracy were acceptable. The validated method was then applied to authentic blood samples and has proved to be a simple, fast and reliable procedure for the determination of paraquat in blood.


Assuntos
Teste em Amostras de Sangue Seco/métodos , Herbicidas/sangue , Paraquat/sangue , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Humanos
15.
Nanoscale ; 10(31): 15071-15077, 2018 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-30059107

RESUMO

Mobility engineering is one of the most important challenges that determine the optoelectronic performance of two-dimensional (2D) materials. So far, charged-impurity scattering and electrical-contact barriers have been suppressed through high-κ dielectrics and seamless contact engineering, giving rise to carrier-mobility improvement in exfoliated 2D semiconducting MoS2. Here we demonstrate a facile and scalable technique to effectively suppress both Coulomb scattering and electron-phonon scattering via the HfO2 overlayer, resulting in a large mobility improvement in CVD-grown monolayer MoS2, in excess of 60 cm2 V-1 s-1. Surface passivation and suppression of Coulomb scattering can partially contribute to the mobility increase. Interestingly, we correlate the mobility increase with phonon quenching through Raman and temperature-dependent mobility measurements. The experimental method is facile, industrially scalable, and renders phonon engineering an additional leverage towards further improvements in 2D semiconductor mobility and device performance.

16.
Chin J Integr Med ; 2018 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-29915907

RESUMO

OBJECTIVE: To investigate the prevalence and spectrum of complementary and alternative medicine (CAM) application and its related-factors in Parkinson's disease (PD) patients in China. METHODS: A structured questionnaire regarding the use of CAMs was administered to PD patients by face-to-face interview. Demographic and social variables, clinical characteristics and treatments, and the related factors of PD were also surveyed. RESULTS: Ninety out of 113 patients (79.6%) reported that they had received CAMs treatment, of which 48.6% (55/113) patients had received CAMs treatment for PD. The top 3 kinds of CAMs for PD were Chinese materia medica, rehabilitation exercise, and acupuncture ordinally. The source of information regarding CAMs treatment mainly came from relatives and friends (51.8%, 73 cases), followed by physicians (31.9%, 45 cases), and medias such as television, newspapers or the internet (16.3%, 28 cases). Fifty percent of CAM users reported a good therapeutic efficacy, whereas 39% patients reported that they felt neither better nor worse after the treatment, while 11% patients claimed worsening of symptoms. Multiple correspondence analyses survey found the main factors affecting the selectivity of CAMs ranked in the following order: income, education, occupation, habitation, age at onset, Hoehn and Yahr staging, PD duration, and gender. CONCLUSION: CAMs, especially Chinese materia medica, rehabilitation exercise, and acupuncture, are widely used for PD patients in China.

17.
Appl Opt ; 57(10): 2474-2481, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29714230

RESUMO

We propose a design tool for the family of circular photonic crystal fiber (C-PCF) supporting orbital angular momentum modes. The calibrated normalized parameters for the C-PCF family are presented. The information about the cutoff condition of modes, the number of modes supported in fibers, and the effective index difference between adjacent modes can be obtained by using the design tool. Also, the mode properties, such as confinement loss, effective mode area (Aeff), and spin-orbital coupling are analyzed using the design tool. At the end of paper, we also give some fiber design examples by using the design tool.

18.
Viruses ; 10(5)2018 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-29772712

RESUMO

Here, we report the anti-human immunodeficiency virus (HIV) potency and underlying mechanisms of a Keggin polyoxometalate (PT-1, K6HPTi2W10O40). Our findings showed that PT-1 exhibited highly potent effects against a diverse group of HIV type 1 (HIV-1) strains and displayed low cytotoxicity and genotoxicity. The time-addition assay revealed that PT-1 acted at an early stage of infection, and these findings were supported by the observation that PT-1 had more potency against Env-pseudotyped virus than vesicular stomatitis virus glycoprotein (VSVG) pseudotyped virus. Surface plasmon resonance binding assays and flow cytometry analysis showed that PT-1 blocked the gp120 binding site in the CD4 receptor. Moreover, PT-1 bound directly to gp41 NHR (N36 peptide), thereby interrupting the core bundle formation of gp41. In conclusion, our data suggested that PT-1 may be developed as a new anti-HIV-1 agent through its effects on entry inhibition.


Assuntos
Antivirais/farmacologia , HIV-1/efeitos dos fármacos , Titânio/química , Compostos de Tungstênio/farmacologia , Internalização do Vírus/efeitos dos fármacos , Animais , Antivirais/química , Antivirais/toxicidade , Antígenos CD4/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citometria de Fluxo , Proteína gp120 do Envelope de HIV/metabolismo , Proteína gp41 do Envelope de HIV/biossíntese , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/metabolismo , HIV-1/fisiologia , Humanos , Masculino , Camundongos , Fragmentos de Peptídeos/metabolismo , Ligação Proteica/efeitos dos fármacos , Ressonância de Plasmônio de Superfície , Compostos de Tungstênio/química , Compostos de Tungstênio/toxicidade
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 202: 382-388, 2018 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-29807336

RESUMO

A novel fluorescent method based on tetracycline-binding aptamers and the luminescence of SYBR Green I (SGI) was established for the sensitive and selective detection of tetracycline. Under natural conditions, the aptamers of tetracycline show the G-quadruplex spatial structures while SGI is nearly nonfluorescent in aqueous solution. After mixture with the G-quadruplex structured aptamers, SGI can recognize and intercalate into the aptamers, resulting in a strong fluorescence emission. When the target tetracycline was added into the solution, the specific recognition and high-affinity binding of aptamers with tetracycline will induce the conformational changes of aptamers from G-quadruplex structures to hairpin structures. Thereafter, SGI will be released from the aptamer molecules, leading to the fluorescence decline. The quantitative detection of tetracycline can be achieved by measuring the fluorescence change of the system. Under the optimum conditions, the linear range of tetracycline in the milk was from 5 to 25 µg/mL, and the detection limit was as low as 0.10 µg/mL. The recoveries of the spiked milk samples were in the range of 98.98%-104.67% with the relative standard deviations (RSDs) of 0.16%-0.67%, and the results were in agreement with those from HPLC. Therefore, the biosensor based on the specific recognition of aptamers and the fluorescence properties of SGI can detect the tetracycline in milk accurately, rapidly and specifically.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais , Luminescência , Compostos Orgânicos/química , Tetraciclinas/análise , Animais , Dicroísmo Circular , Fluorescência , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Leite/química , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/química , Espectrometria de Fluorescência
20.
Opt Express ; 26(6): 7211-7226, 2018 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-29609407

RESUMO

A window-split frequency domain Kalman scheme is proposed in this paper for the equalization of large polarization mode dispersion (PMD) and ultra-fast rotation of state-of-polarization (RSOP) which is an extreme environment due to the Kerr effect and the Faraday effect under the lightning strike near the fiber cables. In order to carry out the proposed Kalman scheme, we give a simplified and equivalent fiber channel model as a replacement for the general model of the polarization effect of the co-existence of PMD and RSOP. With this fiber channel model, we can conduct compensation for PMD in the frequency domain and tracking RSOP in time domain. A half analytical and half empirical theory for the initialization of the process and measurement noise covariance is also presented in theory and verified by the numerical simulation. The performance of the proposed Kalman scheme is checked in the 28Gbaud PDM-QPSK coherent system built on both simulation and experiment platforms. The simulation and experiment results confirm that compared with the generally used constant modulus algorithm (CMA), the proposed scheme provides excellent performance and stability to cope with large range DGD from 20ps to 200ps and RSOP from 200krad/s to 2Mrad/s, with less computational complexity.

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