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Sample records for adhered fbg strain

  1. Strain evaluation of strengthened concrete structures using FBG sensors

    NASA Astrophysics Data System (ADS)

    Lau, Kin-tak; Zhou, Li-min; Ye, Lin

    1999-12-01

    Fibre-optic Bragg Grating (FBG) sensor presents a great deal of potential in monitoring the internal status of the concrete structures after repairing or strengthening by an external adhered reinforcement. It can be used in a variety of configurations ranging from pointwise to multi-point strain measurement in order to investigate the strain distribution of the structures. In this paper, an experimental investigation on the rectangular notched-concrete beam, which was strengthened by glass fibre composites with the embedment of multiplexing FBG sensors is presented. Three point bending test was performed to investigate the strain profile of the specimen. Frequency modulated continuous wave (FMCW) technique was used to measure the strain variation of the fibre-grating regions. The results give a good agreement with the electrical resistance strain gauge in early loading condition. The difference of the strain-measuring results between the strain-gauge and FBG sensor was increased when further increasing the applied load. It was suspected that the micro/marco cracks occurred on the concrete surface and that the externally bonded strain-measuring device cannot be detected.

  2. Strain evaluation of strengthened concrete structures using FBG sensors

    SciTech Connect

    Lau Kintak; Zhou Limin; Ye Lin

    1999-12-02

    Fibre-optic Bragg Grating (FBG) sensor presents a great deal of potential in monitoring the internal status of the concrete structures after repairing or strengthening by an external adhered reinforcement. It can be used in a variety of configurations ranging from pointwise to multi-point strain measurement in order to investigate the strain distribution of the structures. In this paper, an experimental investigation on the rectangular notched-concrete beam, which was strengthened by glass fibre composites with the embedment of multiplexing FBG sensors is presented. Three point bending test was performed to investigate the strain profile of the specimen. Frequency modulated continuous wave (FMCW) technique was used to measure the strain variation of the fibre-grating regions. The results give a good agreement with the electrical resistance strain gauge in early loading condition. The difference of the strain-measuring results between the strain-gauge and FBG sensor was increased when further increasing the applied load. It was suspected that the micro/marco cracks occurred on the concrete surface and that the externally bonded strain-measuring device cannot be detected.

  3. Multiplexed FBG strain measurement system

    NASA Astrophysics Data System (ADS)

    Helsztynski, Jerzy; Lewandowski, Lech; Jasiewicz, Wieslaw; Jedrzejewski, Kazimierz P.

    2008-11-01

    The idea and, design and realization of fiber Bragg grating multiplexing system is given. Special Bragg gratings with very long and linear side slopes were practically realized. They were tuned for different wavelengths distanced 9nm in each measurement channel. The system was applied for strain control. Special spectrophotometer with linear photodiode array was made. For flexible distributed multiplexing of many sensor channels fiber-optic switches were used.

  4. FlexPatch: a rugged miniature FBG strain sensor

    NASA Astrophysics Data System (ADS)

    Ferguson, Steve; Snyder, Don; Graver, Tom; Méndez, Alexis

    2007-04-01

    The design and development of a novel opto-mechanical strain sensor-called FlexPatch-based on the use of an optical fiber Bragg grating (FBG) mounted into a custom-made miniature metallic flexure is reported. The FBG sensing element is attached to a carrier flexure using proprietary bonding process which ensures a linear, drift-free and repeatable strain response even under severe moisture and temperature conditions. The sensor is uncompensated for temperature effects, but has undergone extensive mechanical and environmental testing and is qualified for use in a strain range of +/- 2,500μɛ with a gage factor of 1.2pm/μɛ over a temperature range from -40° to 120°C, and a fatigue life >100x10 6 cycles. The FlexPatch is intended for use in diverse sensing and monitoring applications and can be installed onto surfaces by epoxy bonding or spot welding.

  5. Nickel plating of FBG strain sensors for nuclear applications

    NASA Astrophysics Data System (ADS)

    Perry, Marcus; Niewczas, Pawel; Johnston, Michael; Mackersie, John

    2011-05-01

    We present a method for plating FBG strain sensors with a strongly-bonded, hermetic nickel layer, without exposure of the fiber to corrosive environments. A 1μm thick, highly adhesive chrome layer is deposited onto bare fibers via evaporation. Addition of an inert and electrically conductive gold layer then allows the fiber to be electroplated with a 50-100μm nickel layer. Finite element models have confirmed that nickel plated FBG sensors can be brazed into steel structures and used to monitor local strain and temperature. Embedding gratings that are temperature and radiation resistant will be particularly applicable to the structural health monitoring of steel prestressing tendons used in the concrete containments of nuclear power plants and other safety-significant structures.

  6. Design and application of FBG strain experimental apparatus in high temperature

    NASA Astrophysics Data System (ADS)

    Xia, Zhongcheng; Liu, Yueming; Gao, Xiaoliang

    2014-09-01

    Fiber Bragg Grating (FBG) sensing technology has many applications, and it's widely used in detection of temperature, strain and etc. Now the application of FBG sensor is limited to the temperature below 200°C owing to the so called High Temperature Erasing Phenomenon. Strain detection over 200°C is still an engineering challenge since high temperature has a bad influence on the sensor, testing equipment and test data, etc, thus effective measurement apparatus are needed to ensure the accuracy of the measurement over 200°C, but there are no suitable FBG strain experimental apparatus in high temperature to date. In this paper a high temperature FBG strain experimental apparatus has been designed to detect the strain in high temperature. In order to verify working condition of the high temperature FBG strain, an application of FBG strain sensing experiment was given in this paper. The high temperature FBG strain sensor was installed in the apparatus, the internal temperature of experimental apparatus was controlled from -20 to 300°C accurately, and strain loading was given by the counterweight, then the data was recorded through electrical resistance strain measurement and optical sensing interrogator. Experimental data result shows that the high temperature FBG strain experimental apparatus can work properly over 200°C. The design of the high temperature FBG strain experimental apparatus are demonstrated suitable for high temperature strain gauges and FBG strain sensors , etc, which can work under the temperature of -20 ~ 300°C, the strain of -1500 ~ +1500μepsilon and the wavelength resolution of 1pm.

  7. Influence of metal bonding layer on strain transfer performance of FBG

    NASA Astrophysics Data System (ADS)

    Liu, Hao; Chen, Weimin; Zhang, Peng; Liu, Li; Shu, Yuejie; Wu, Jun

    2013-01-01

    Metal bonding layer seriously affects the strain transfer performance of Fiber Bragg Grating (FBG). Based on the mode of FBG strain transfer, the influence of the length, the thickness, Poisson's ratio, elasticity modulus of metal bonding layer on the strain transfer coefficient of FBG is analyzed by numerical simulation. FBG is packaged to steel wire using metal bonding technology of FBG. The tensile tests of different bonding lengths and elasticity modulus are carried out. The result shows the strain transfer coefficient of FBGs are 0.9848,0.962 and their average strain sensitivities are 1.076 pm/μɛ,1.099 pm/μɛ when the metal bonding layer is zinc, whose lengths are 15mm, 20mm, respectively. The strain transfer coefficient of FBG packaged by metal bonding layer raises 8.9 percent compared to epoxy glue package. The preliminary experimental results show that the strain transfer coefficient increases with the length of metal bonding layer, decreases with the thickness of metal bonding layer and the influence of Poisson's ratio can be ignored. The experiment result is general agreement with the analysis and provides guidance for metal package of FBG.

  8. Monitoring of hardening and hygroscopic induced strains in a calcium phosphate bone cement using FBG sensor.

    PubMed

    Bimis, A; Karalekas, D; Bouropoulos, N; Mouzakis, D; Zaoutsos, S

    2016-07-01

    This study initially deals with the investigation of the induced strains during hardening stage of a self-setting calcium phosphate bone cement using fiber-Bragg grating (FBG) optical sensors. A complementary Scanning Electron Microscopy (SEM) investigation was also conducted at different time intervals of the hardening period and its findings were related to the FBG recordings. From the obtained results, it is demonstrated that the FBG response is affected by the microstructural changes taking place when the bone cement is immersed into the hardening liquid media. Subsequently, the FBG sensor was used to monitor the absorption process and hygroscopic response of the hardened and dried biocement when exposed to a liquid/humid environment. From the FBG-based calculated hygric strains as a function of moisture concentration, the coefficient of moisture expansion (CME) of the examined bone cement was obtained, exhibiting two distinct linear regions.

  9. Monitoring of hardening and hygroscopic induced strains in a calcium phosphate bone cement using FBG sensor.

    PubMed

    Bimis, A; Karalekas, D; Bouropoulos, N; Mouzakis, D; Zaoutsos, S

    2016-07-01

    This study initially deals with the investigation of the induced strains during hardening stage of a self-setting calcium phosphate bone cement using fiber-Bragg grating (FBG) optical sensors. A complementary Scanning Electron Microscopy (SEM) investigation was also conducted at different time intervals of the hardening period and its findings were related to the FBG recordings. From the obtained results, it is demonstrated that the FBG response is affected by the microstructural changes taking place when the bone cement is immersed into the hardening liquid media. Subsequently, the FBG sensor was used to monitor the absorption process and hygroscopic response of the hardened and dried biocement when exposed to a liquid/humid environment. From the FBG-based calculated hygric strains as a function of moisture concentration, the coefficient of moisture expansion (CME) of the examined bone cement was obtained, exhibiting two distinct linear regions. PMID:26807773

  10. On the use of optical fiber Bragg grating (FBG) sensor technology for strain modal analysis

    NASA Astrophysics Data System (ADS)

    Peeters, Bart; dos Santos, Fábio Luis Marques; Pereira, Andreia; Araujo, Francisco

    2014-05-01

    This paper discusses the use of optical fiber Bragg grating (FBG) strain sensors for structural dynamics measurements. For certain industrial applications, there is an interest to use strain sensors rather than or in combination with accelerometers for experimental modal analysis. Classical electrical strain gauges can be used hereto, but optical strain sensors are an interesting alternative with some very specific advantages. This paper gives an overview of dynamic strain measurements in industrial applications, discusses the benefits of FBG sensors and reviews their measurement principle. Finally, the concept of strain modal analysis is introduced and a helicopter main rotor blade vibration testing and analysis case study is presented.

  11. Cracking monitoring by FBG strain sensor in the small scale dam model

    NASA Astrophysics Data System (ADS)

    Ren, Liang; Li, Hongnan; Li, Dongsheng

    2009-03-01

    Accurate measurement of strain variation and effective prediction of failure within models has been a major objective for strain sensors in dam model tests. In this paper, a FBG strain sensor with enhanced strain sensitivity and packaged by two gripper tubes is presented and applied in the seismic tests of a small scale dam model. This paper discusses the principle of enhanced sensitivity of the FBG strain sensor. Calibration experiments were conducted to evaluate the sensor's strain transferring characteristics on plates of different material. This paper also investigates the applicability of the FBG strain sensors in seismic tests of a dam model by conducting a comparison between the test measurements of FBG sensors and analytical predictions, monitoring the failure progress and predicting the cracking inside the dam model. Results of the dam model tests prove that this FBG strain sensor has the advantages of small size, high precision and embedability, demonstrate promising potential in cracking and failure monitoring and in identification of the dam model.

  12. Temperature-compensated strain measurement of full-scale small aircraft wing structure using low-cost FBG interrogator

    NASA Astrophysics Data System (ADS)

    Kim, J. H.; Lee, Y. G.; Park, Y.; Kim, C. G.

    2013-04-01

    Recently, health and usage monitoring systems (HUMS) are being studied to monitor the real-time condition of aircrafts during flight. HUMSs can prevent aircraft accidents and reduce inspection time and cost. Fiber Bragg grating (FBG) sensors are widely used for aircraft HUMSs with many advantages such as light weight, small size, easy-multiplexing, and EMI immunity. However, commercial FBG interrogators are too expensive to apply for small aircrafts. Generally the cost of conventional FBG interrogators is over 20,000. Therefore, cost-effective FBG interrogation systems need to be developed for small aircraft HUMSs. In this study, cost-effective low speed FBG interrogator was applied to full-scale small aircraft wing structure to examine the operational applicability of the low speed FBG interrogator to the monitoring of small aircrafts. The cost of the developed low speed FBG interrogator was about 10,000, which is an affordable price for a small aircraft. 10 FBG strain sensors and 1 FBG temperature sensor were installed on the surface of the full-scale wing structure. Load was applied to the tip of the wing structure, and the low speed interrogator detected the change in the center wavelength of the FBG sensors at the sampling rate of 10Hz. To assess the applicability of the low-cost FBG interrogator to full-scale small aircraft wing structure, a temperature-compensated strain measurement algorithm was verified experimentally under various loading conditions of the wing structure with temperature variations.

  13. Analysis, compensation, and correction of temperature effects on FBG strain sensors

    NASA Astrophysics Data System (ADS)

    Haber, T. C.; Ferguson, S.; Guthrie, D.; Graver, T. W.; Soller, B. J.; Mendez, Alexis

    2013-05-01

    One of the most common fiber optic sensor (FOS) types used are fiber Bragg gratings (FBG), and the most frequently measured parameter is strain. Hence, FBG strain sensors are one of the most prevalent FOS devices in use today in structural sensing and monitoring in civil engineering, aerospace, marine, oil and gas, composites and smart structure applications. However, since FBGs are simultaneously sensitive to both temperature and strain, it becomes essential to utilize sensors that are either fully temperature insensitive or, alternatively, properly temperature compensated to avoid erroneous measurements. In this paper, we introduce the concept of measured "total strain", which is inherent and unique to optical strain sensors. We review and analyze the temperature and strain sensitivities of FBG strain sensors and decompose the total measured strain into thermal and non-thermal components. We explore the differences between substrate CTE and System Thermal Response Coefficients, which govern the type and quality of thermal strain decomposition analysis. Finally, we present specific guidelines to achieve proper temperature-insensitive strain measurements by combining adequate installation, sensor packaging and data correction techniques.

  14. Strain Measurement Using FBG on COPV in Stress Rupture Test

    NASA Technical Reports Server (NTRS)

    Banks, Curtis; Grant, Joseph

    2007-01-01

    to better predict the remaining life of the STS COPVs. The primary test objective is obtaining data to verify the hypothesis of a radially oriented thru-thickness stress-riser in the COPV composite whose magnitude is a function of the applied pressure and the load history. The anticipated load dependent response follows from the constitutive behavior of the composite overwrap so data to quantify its nonlinear and time dependent response will be sought. The objective of the Fiber Braggs Gratings (FBGs) were to advance the state-of-the-art by developing techniques using FBG sensors that are capable of assessing stress-rupture degradation in Kevlar COPVs in a health monitoring mode (1). Moreover, they sought to answer questions of how embedded sensors affect overall integrity of the structure. And lastly, they sought to provide an important link in the overall stress rupture study that will help close the loop on the COPV fabrication process. NDE inspection methods will be used from start to finish and FBG will be an integral link within the overall chain.

  15. Modal macro-strain vector based damage detection methodology with long-gauge FBG sensors

    NASA Astrophysics Data System (ADS)

    Xu, Bin; Liu, Chongwu W.; Masri, Sami F.

    2009-07-01

    Advances in optic fiber sensing technology provide easy and reliable way for the vibration-based strain measurement of engineering structures. As a typical optic fiber sensing techniques with high accuracy and resolution, long-gauge Fiber Bragg Grating (FBG) sensors have been widely employed in health monitoring of civil engineering structures. Therefore, the development of macro strain-based identification methods is crucial for damage detection and structural condition evaluation. In the previous study by the authors, a damage detection algorithm for a beam structure with the direct use of vibration-based macro-strain measurement time history with neural networks had been proposed and validated with experimental measurements. In this paper, a damage locating and quantifying method was proposed using modal macrostrain vectors (MMSVs) which can be extracted from vibration induced macro-strain response measurement time series from long-gage FBG sensors. The performance of the proposed methodology for damage detection of a beam with different damage scenario was studied with numerical simulation firstly. Then, dynamic tests on a simply-supported steel beam with different damage scenarios were carried out and macro-strain measurements were employed to detect the damage severity. Results show that the proposed MMSV based structural identification and damage detection methodology can locate and identify the structural damage severity with acceptable accuracy.

  16. Distributed strain measurement system in one-dimensional by means of multipoint FBG sensing

    NASA Astrophysics Data System (ADS)

    Yin, Hao; Zhu, Jun; Tang, Haiyu; Wang, Hui; Zhang, Zhao; Shui, Tao; Yu, Benli

    2013-12-01

    In this paper, we described a distributed strain measurement scheme in one-dimensional. The sensing information of FBG is demodulated by a CCD spectrometer, the discrete strain is achieved by fitting and processing discrete signal demodulated utilizing labVIEW virtual instrument technology. Then it could be achieved by Using polynomial fitting method to one-dimensional discrete strain distributed detection. Experimentally, measurement was implemented in Cantilever to prove the system performance. The experimental result shows that the system can reflect the strain distribution in one-dimensional and an order strain modal characteristics of cantilever accurately. The detection system can achieve real-time and dynamic measurements, the response time for 2kHz, the response accuracy for 4μɛ.

  17. Oil pipeline geohazard monitoring using optical fiber FBG strain sensors (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Salazar-Ferro, Andres; Mendez, Alexis

    2016-04-01

    Pipelines are naturally vulnerable to operational, environmental and man-made effects such as internal erosion and corrosion; mechanical deformation due to geophysical risks and ground movements; leaks from neglect and vandalism; as well as encroachments from nearby excavations or illegal intrusions. The actual detection and localization of incipient and advanced faults in pipelines is a very difficult, expensive and inexact task. Anything that operators can do to mitigate the effects of these faults will provide increased reliability, reduced downtime and maintenance costs, as well as increased revenues. This talk will review the on-line monitoring of an extensive network of oil pipelines in service in Colombia using optical fiber Bragg grating (FBG) strain sensors for the measurement of strains and bending caused by geohazard risks such as soil movements, landslides, settlements, flooding and seismic activity. The FBG sensors were mounted on the outside of the pipelines at discrete locations where geohazard risk was expected. The system has been in service for the past 3 years with over 1,000 strain sensors mounted. The technique has been reliable and effective in giving advanced warning of accumulated pipeline strains as well as possible ruptures.

  18. Development of tube-packaged FBG strain sensor and application in the vibration experiment of submarine pipeline model

    NASA Astrophysics Data System (ADS)

    Ren, Liang; Li, Hong-Nan; Sun, Li; Li, Dong-Sheng

    2005-02-01

    Optical fiber sensors have received increasing attention in the fields of aeronautic and civil engineering for their superior ability of explosion proof, immunity to electromagnetic interference and high accuracy, especially fitting for measurement applications in harsh environment. In this paper, a novel FBG (fiber Bragg grating) strain sensor, which was packaged in a 1.2mm stainless steel tube by epoxy resin, was developed. Experiments were conducted on the universal material testing machine to calibrate its strain transferring characteristics. The sensor has the advantages of small size, high precision and flexible use, and demonstrates promising potentials. Ten of tube-packaged strain FBG sensors were applied in the vibration experiment of submarine pipeline model. The strain measured by FBG sensor agrees well with the electric resistance strain sensor.

  19. Development of tube-packaged FBG strain sensor and application in the vibration experiment of submarine pipeline model

    NASA Astrophysics Data System (ADS)

    Ren, Liang; Li, Hong-Nan; Sun, Li; Li, Dong-Sheng

    2005-05-01

    Optical fiber sensors have received increasing attention in the fields of aeronautic and civil engineering for their superior ability of explosion proof, immunity to electromagnetic interference and high accuracy, especially fitting for measurement applications in harsh environment. In this paper, a novel FBG (fiber Bragg grating) strain sensor, which was packaged in a 1.2mm stainless steel tube by epoxy resin, was developed. Experiments were conducted on the universal material testing machine to calibrate its strain transferring characteristics. The sensor has the advantages of small size, high precision and flexible use, and demonstrates promising potentials. Ten of tube-packaged strain FBG sensors were applied in the vibration experiment of submarine pipeline model. The strain measured by FBG sensor agrees well with the electric resistance strain sensor.

  20. Longitudinal force measurement in continuous welded rail with bi-directional FBG strain sensors

    NASA Astrophysics Data System (ADS)

    Wang, Ping; Xie, Kaize; Shao, Liyang; Yan, Lianshan; Xu, Jingmang; Chen, Rong

    2016-01-01

    In this work, a new method has been proposed to accurately determine longitudinal force measurement in continuous welded rail (CWR) with bi-directional fiber Bragg grating (B-FBGs) strain sensors (vertically and longitudinally installed according to the axis of rail). The response of B-FBGs has been theoretically analyzed by binding on CWR under different restrained conditions, where the coefficient of strain sensitivity of FBG is calibrated by its temperature sensitivity. Then the proposed sensor structure has been installed at two elaborately selected points on the subgrade on a Chinese high-speed railway in field. The experiment lasts for about 23 h. During the experiment, the rail temperature varied by about 7.8 °C and the differentials of relative value of wavelength change of B-FBGs of two points were 1.7850 × 10-5 and 1.4969 × 10-5. The maximum difference between the experimental and theoretical results is 13.8 kN. The experimental results agree with the theoretical analysis very well. To guarantee the measurement accuracy of over 95%, the ratio of strain sensitivity coefficients of two FBG sensors of B-FBGs structure at one test point shall be within 0.78 ˜ 1.22.

  1. Research on the FBG strain gauge used for the safety monitoring of high-temperature pressure pipes

    NASA Astrophysics Data System (ADS)

    Cai, Qing-mu; Liu, Yue-ming; He, Zheng-yan; Chen, Zhong-you; Huang, Chang-qing; Lou, Jun; Tian, Wei-jian

    2012-10-01

    High temperature pressure pipes were widely used in the chemical, oil companies and power plants, but the pipe burst incidents occurred from time to time, which had caused some damages on people's lives and property. Thus, in this paper, with the aim to solve this problem, a FBG (FBG: Fiber Bragg Grating) strain gauge structure which consists of three FBGs is designed and fabricated based on the theoretical strain and stress analysis. The strain gauge can be used for the real-time surface strain monitoring of high temperature pressure pipes. In the strain gauge, the elastic hightemperature alloy(10MoWVNb) is chosen as the substrate. The three FBGs with a similar performance are fabricated on the substrate with the high-temperature glue. Among the three FBGs, FBG1 is used for the horizontal strain sensing of high temperature pressure pipes., FBG2 is used for the longitudinal strain of high temperature pressure pipes, and FGB3 is used for temperature compensation. The strain gauge has a feature of high temperature resistance, temperature compensation and two-dimensional strain measurement. The experiment result shows that : the sensing ranges of temperature is 0~300°C, the transverse strain sensitivity is 1.110nm/μɛ, the temperature sensitivity is 0.0213nm/°C; The longitudinal strain sensitivity is 1.104nm/μɛ, the temperature sensitivity is 0.0212nm/°C; the temperature sensitivity is 0.0103nm/°C. Therefore, the strain gauge can meet the needs of the high temperature and pressure pipes.

  2. Correlation-based methods in calibrating an FBG sensor with strain field non-uniformity

    NASA Astrophysics Data System (ADS)

    Cieszczyk, S.

    2015-12-01

    Fibre Bragg gratings have many sensing applications, mainly for measuring strain and temperature. The physical quantity that influences grating uniformly along its length causes a related shift of the Bragg wavelength. Many peak detection algorithms have been proposed, among which the most popular are the detection of maximum intensity, the centroid detection, the least square method, the cross-correlation, auto-correlation and fast phase correlation. Nonuniform gratings elongation is a cause of spectrum deformation. The introduction of non-uniformity can be intentional or appear as an unintended effect of placing sensing elements in the tested structure. Heterogeneous impacts on grating may result in additional errors and the difficulty in tracking the Bragg wavelength based on a distorted spectrum. This paper presents the application of correlation methods of peak wavelength shifts estimation for non-uniform Bragg grating elongation. The autocorrelation, cross-correlation and fast phase correlation algorithms are considered and experimental spectra measured for axisymmetric strain field along the Bragg grating are analyzed. The strain profile consists of constant and variable components. The results of this study indicate the properties of correlation algorithms applied to moderately non-uniform elongation of an FBG sensor.

  3. Thermal characterization of FBG strain gauges for the monitoring of the cupola of Duomo di Milano

    NASA Astrophysics Data System (ADS)

    Cigada, Alfredo; Comolli, Lorenzo; Giussani, Alberto; Roncoroni, Fabio; Zenucchi, Fabio

    2011-05-01

    The incoming restoration works of Duomo di Milano main spire requires a continuous structural health monitoring of the cupola supporting it. For reasons mainly connected to the lightning hazard, fiber optic sensors have been selected, based on FBG technology. Strain of the lower part of the vaulting-rigs inside the octagonal cupola is the measurement of interest. Being the expected signals very small and the thermal disturbances very important, a thermal characterization of two types of commercial strain gauges was carried out in laboratory with a thermal chamber and a block of the same marble used for the Duomo construction. This allowed to find a relationship later used to compensate any thermal effects, leading to the extraction of the mechanical load contribution only. An uncertainty analysis gave a result of 5 to 10 μm/m in the tested temperature range -5 °C to +40 °C. The future work will expand the monitoring system to more measurement points and it is expected this can provide an important diagnostic tool during restoration operations.

  4. Damage Detection Based on Static Strain Responses Using FBG in a Wind Turbine Blade.

    PubMed

    Tian, Shaohua; Yang, Zhibo; Chen, Xuefeng; Xie, Yong

    2015-08-14

    The damage detection of a wind turbine blade enables better operation of the turbines, and provides an early alert to the destroyed events of the blade in order to avoid catastrophic losses. A new non-baseline damage detection method based on the Fiber Bragg grating (FBG) in a wind turbine blade is developed in this paper. Firstly, the Chi-square distribution is proven to be an effective damage-sensitive feature which is adopted as the individual information source for the local decision. In order to obtain the global and optimal decision for the damage detection, the feature information fusion (FIF) method is proposed to fuse and optimize information in above individual information sources, and the damage is detected accurately through of the global decision. Then a 13.2 m wind turbine blade with the distributed strain sensor system is adopted to describe the feasibility of the proposed method, and the strain energy method (SEM) is used to describe the advantage of the proposed method. Finally results show that the proposed method can deliver encouraging results of the damage detection in the wind turbine blade.

  5. Damage Detection Based on Static Strain Responses Using FBG in a Wind Turbine Blade

    PubMed Central

    Tian, Shaohua; Yang, Zhibo; Chen, Xuefeng; Xie, Yong

    2015-01-01

    The damage detection of a wind turbine blade enables better operation of the turbines, and provides an early alert to the destroyed events of the blade in order to avoid catastrophic losses. A new non-baseline damage detection method based on the Fiber Bragg grating (FBG) in a wind turbine blade is developed in this paper. Firstly, the Chi-square distribution is proven to be an effective damage-sensitive feature which is adopted as the individual information source for the local decision. In order to obtain the global and optimal decision for the damage detection, the feature information fusion (FIF) method is proposed to fuse and optimize information in above individual information sources, and the damage is detected accurately through of the global decision. Then a 13.2 m wind turbine blade with the distributed strain sensor system is adopted to describe the feasibility of the proposed method, and the strain energy method (SEM) is used to describe the advantage of the proposed method. Finally results show that the proposed method can deliver encouraging results of the damage detection in the wind turbine blade. PMID:26287200

  6. Damage Detection Based on Static Strain Responses Using FBG in a Wind Turbine Blade.

    PubMed

    Tian, Shaohua; Yang, Zhibo; Chen, Xuefeng; Xie, Yong

    2015-01-01

    The damage detection of a wind turbine blade enables better operation of the turbines, and provides an early alert to the destroyed events of the blade in order to avoid catastrophic losses. A new non-baseline damage detection method based on the Fiber Bragg grating (FBG) in a wind turbine blade is developed in this paper. Firstly, the Chi-square distribution is proven to be an effective damage-sensitive feature which is adopted as the individual information source for the local decision. In order to obtain the global and optimal decision for the damage detection, the feature information fusion (FIF) method is proposed to fuse and optimize information in above individual information sources, and the damage is detected accurately through of the global decision. Then a 13.2 m wind turbine blade with the distributed strain sensor system is adopted to describe the feasibility of the proposed method, and the strain energy method (SEM) is used to describe the advantage of the proposed method. Finally results show that the proposed method can deliver encouraging results of the damage detection in the wind turbine blade. PMID:26287200

  7. Application of an ultra-high-resolution FBG strain sensor for crustal deformation measurements at the Aburatsubo Bay, Japan

    NASA Astrophysics Data System (ADS)

    Tokunaga, T.; Liu, Q.; He, Z.; Mogi, K.; Matsui, H.; Wang, H. F.; Kato, T.

    2011-12-01

    For crustal deformation measurements, high-resolution strain sensors on the order of tens of nano-strains are desirable. Current sensors for this purpose include quartz-tube extensometers, free-space laser interferometers, and borehole strainmeters. The former two sensors show quite high strain resolution, however, these are large in size, from tens to hundreds of meter long, and hence, are difficult to measure spatial strain distribution. The optical fiber strain sensors have advantages of multiplexing capability and relatively low cost, and are widely adopted in the applications for structural health monitoring of civil structures such as bridges and buildings. Thus, as long as the strain resolution can be high enough to meet the requirement of crustal deformation measurements, fiber strain sensors can be an attractive tool. We have been developing an ultra-high strain-resolution fiber Bragg grating (FBG) sensor for static strain measurement, interrogated by a narrow line-width tunable laser. The sensor consists of a pair of FBGs, one for strain sensing and the other for temperature compensation. The Bragg wavelength difference between the two FBGs is evaluated using a cross-correlation algorithm. We already demonstrated that an ultra-high resolution corresponding to 2.6 nano-strain was obtained in the case where no strain was applied to the sensor, which was considered to be the ultimate performance of our measurement system. By directly applying variable strains to the developed sensor with a piezo-stage, a resolution of 17.6 nano-strain was demonstrated. This time, the sensor was installed into the vault at Aburatsubo, Japan, to measure crustal deformation caused by ocean tide, and the measured data were compared with the results obtained by a quartz-tube extensometer at the site, which has been measured by the University of Tokyo's Earthquake Research Institute. The deformation induced by oceanic tide was measured by the FBG sensor with the resolution about

  8. Wavelet analysis on vibration modal frequency measurement at a low level of strain of the turbine blade using FBG sensors

    NASA Astrophysics Data System (ADS)

    Huang, Xue-feng; Liu, Yan; Luo, Dan; Wang, Guan-qing; Ding, Ning; Xu, Jiang-rong; Huang, Xue-jing

    2010-01-01

    Vibration modal frequency measurement of a turbine blade was investigated by using fiber Bragg grating (FBG) sensors for their adaptation for a low level of strain at high frequency. However, the signal-to-noise ratio was so low that it was very difficult to identify dominant modal frequency from a raw signal acquired. An attempt was made to solve this problem. First, a bi-linear transform elliptic filter with pass-band and stop-band was proposed to remove electromagnetic interference noise. Second, discrete stationary wavelet transform with a soft threshold was utilized to de-noise the high-frequency part. Third, wavelet packet transform was exploited to decompose the time signal and to obtain the power spectrum and identification of dominant modal frequency. Experimental and analytic results demonstrated that four stages of dominant modal frequencies of the turbine blade without any constraint condition (free vibration) and three stages of dominant modal frequencies with a constraint condition (A-type vibration) were obtained, respectively. To testify to the validity of analytic results, a professional computer random signal and vibration analysis system (CRAS) was used to measure modal frequency. The results illustrated that modal frequencies obtained by the CRAS platform yielded close agreement with those based on FBG sensors. Obviously, wavelet analysis is successfully employed to decode vibration modal frequency from a raw signal of FBG sensors.

  9. Swept optical SSB-SC modulation technique for high-resolution large-dynamic-range static strain measurement using FBG-FP sensors.

    PubMed

    Huang, Wenzhu; Zhang, Wentao; Li, Fang

    2015-04-01

    This Letter presents a static strain demodulation technique for FBG-FP sensors using a suppressed carrier LiNbO(3) (LN) optical single sideband (SSB-SC) modulator. A narrow-linewidth tunable laser source is generated by driving the modulator using a linear chirp signal. Then this tunable single-frequency laser is used to interrogate the FBG-FP sensors with the Pound-Drever-Hall (PDH) technique, which is beneficial to eliminate the influence of light intensity fluctuation of the modulator at different tuning frequencies. The static strain is demodulated by calculating the wavelength difference of the PDH signals between the sensing FBG-FP sensor and the reference FBG-FP sensor. As an experimental result using the modulator, the linearity (R2) of the time-frequency response increases from 0.989 to 0.997, and the frequency-swept range (dynamic range) increases from hundreds of MHz to several GHz compared with commercial PZT-tunable lasers. The high-linearity time-wavelength relationship of the modulator is beneficial for improving the strain measurement resolution, as it can solve the problem of the frequency-swept nonlinearity effectively. In the laboratory test, a 0.67 nanostrain static strain resolution, with a 6 GHz dynamic range, is demonstrated.

  10. A High-Resolution Demodulation Algorithm for FBG-FP Static-Strain Sensors Based on the Hilbert Transform and Cross Third-Order Cumulant

    PubMed Central

    Huang, Wenzhu; Zhen, Tengkun; Zhang, Wentao; Zhang, Fusheng; Li, Fang

    2015-01-01

    Static strain can be detected by measuring a cross-correlation of reflection spectra from two fiber Bragg gratings (FBGs). However, the static-strain measurement resolution is limited by the dominant Gaussian noise source when using this traditional method. This paper presents a novel static-strain demodulation algorithm for FBG-based Fabry-Perot interferometers (FBG-FPs). The Hilbert transform is proposed for changing the Gaussian distribution of the two FBG-FPs’ reflection spectra, and a cross third-order cumulant is used to use the results of the Hilbert transform and get a group of noise-vanished signals which can be used to accurately calculate the wavelength difference of the two FBG-FPs. The benefit by these processes is that Gaussian noise in the spectra can be suppressed completely in theory and a higher resolution can be reached. In order to verify the precision and flexibility of this algorithm, a detailed theory model and a simulation analysis are given, and an experiment is implemented. As a result, a static-strain resolution of 0.9 nε under laboratory environment condition is achieved, showing a higher resolution than the traditional cross-correlation method. PMID:25923938

  11. A High-Resolution Demodulation Algorithm for FBG-FP Static-Strain Sensors Based on the Hilbert Transform and Cross Third-Order Cumulant.

    PubMed

    Huang, Wenzhu; Zhen, Tengkun; Zhang, Wentao; Zhang, Fusheng; Li, Fang

    2015-01-01

    Static strain can be detected by measuring a cross-correlation of reflection spectra from two fiber Bragg gratings (FBGs). However, the static-strain measurement resolution is limited by the dominant Gaussian noise source when using this traditional method. This paper presents a novel static-strain demodulation algorithm for FBG-based Fabry-Perot interferometers (FBG-FPs). The Hilbert transform is proposed for changing the Gaussian distribution of the two FBG-FPs' reflection spectra, and a cross third-order cumulant is used to use the results of the Hilbert transform and get a group of noise-vanished signals which can be used to accurately calculate the wavelength difference of the two FBG-FPs. The benefit by these processes is that Gaussian noise in the spectra can be suppressed completely in theory and a higher resolution can be reached. In order to verify the precision and flexibility of this algorithm, a detailed theory model and a simulation analysis are given, and an experiment is implemented. As a result, a static-strain resolution of 0.9 nε under laboratory environment condition is achieved, showing a higher resolution than the traditional cross-correlation method. PMID:25923938

  12. Performance of a Distributed Simultaneous Strain and Temperature Sensor Based on a Fabry-Perot Laser Diode and a Dual-Stage FBG Optical Demultiplexer

    PubMed Central

    Kim, Suhwan; Kwon, Hyungwoo; Yang, Injae; Lee, Seungho; Kim, Jeehyun; Kang, Shinwon

    2013-01-01

    A simultaneous strain and temperature measurement method using a Fabry-Perot laser diode (FP-LD) and a dual-stage fiber Bragg grating (FBG) optical demultiplexer was applied to a distributed sensor system based on Brillouin optical time domain reflectometry (BOTDR). By using a Kalman filter, we improved the performance of the FP-LD based OTDR, and decreased the noise using the dual-stage FBG optical demultiplexer. Applying the two developed components to the BOTDR system and using a temperature compensating algorithm, we successfully demonstrated the simultaneous measurement of strain and temperature distributions under various experimental conditions. The observed errors in the temperature and strain measured using the developed sensing system were 0.6 °C and 50 με, and the spatial resolution was 1 m, respectively. PMID:24284773

  13. High strain FBG sensors for structural fatigue testing of military aircraft

    NASA Astrophysics Data System (ADS)

    Tejedor, S.; Kopczyk, J.; Nuyens, T.; Davis, C.

    2012-02-01

    This paper reports on a series of tests investigating the performance of Draw Tower Gratings (DTGs) combined with custom-designed broad area packaging and bonding techniques for high-strain sensing applications on Defence platforms. The sensors and packaging were subjected to a series of high-strain static and cyclic loading tests and a summary of these results is presented.

  14. An ultra-high-resolution FBG static-strain sensor for geophysics applications

    NASA Astrophysics Data System (ADS)

    Liu, Qingwen; He, Zuyuan; Tokunaga, Tomochika; Hotate, Kazuo

    2010-09-01

    We report an ultra-high-resolution static-strain measurement with a pair of fiber Bragg gratings (FBGs), one for strain sensing and the other for compensating the error due to temperature disturbance and source drift. The difference between the two FBGs' Bragg wavelengths is evaluated by utilizing a cross-correlation algorithm. The mechanism of noise suppression by the cross-correlation algorithm is quantitatively analyzed and the factor that determines the ability of noise suppression of this algorithm is revealed. The temperature dependence is further subtracted by using a vector operation. When no strain is applied, an ultra-high wavelength resolution corresponding to 2.6 nɛ was obtained, which gives the ultimate performance of the measurement system. With a variable strain applied with a piezo-stage, a resolution of 17.6 nɛ was demonstrated. This is the first demonstration, to the best of our knowledge, that a real-static strain down to 10 nɛ is measured, providing a powerful technique for the measurement in geophysics application.

  15. Temperature and humidity dependent performance of FBG-strain sensors embedded in carbon/epoxy composites

    NASA Astrophysics Data System (ADS)

    Frövel, Malte; Carrión, Gabriel; Gutiérrez, César; Moravec, Carolina; Pintado, José María

    2009-03-01

    Fiber Bragg Grating Sensors, FBGSs, are very promising for Structural Health Monitoring, SHM, of aerospace vehicles due to their capacity to measure strain and temperature, their lightweight harnesses, their multiplexing capacities and their immunity to electromagnetic interferences, within others. They can be embedded in composite materials that are increasingly forming an important part of aerospace structures. The use of embedded FBGSs for SHM purposes is advantageous, but their response under all operative environmental conditions of an aerospace structure must be well understood for the necessary flight certification of these sensors. This paper describes the first steps ahead for a possible in future flight certification of FBGSs embedded in carbon fiber reinforced plastics, CFRP. The investigation work was focused on the validation of the dependence of the FBGS's strain sensitivity in tensile and compression load, in dry and humid condition and in a temperature range from -150°C to 120°C. The test conditions try to simulate the in service temperature and humidity range and static load condition of military aircraft. FBGSs with acrylic and with polyimide coating have been tested. The FBGSs are embedded in both, unidirectional and quasi isotropic carbon/epoxy composite material namely M21/T800 and also MTM-45-1/IM7. Conventional extensometers and strain gages have been used as reference strain sensors. The performed tests show an influence of the testing temperatures, the dry or wet specimen condition, the load direction and the coating material on the sensor strain sensitivity that should be taken into account when using these sensors.

  16. Strain measurements using FBG on composite over wrap pressure vessels (COPV) in stress rupture test

    NASA Astrophysics Data System (ADS)

    Grant, Joseph; Banks, Curtis

    2007-04-01

    Thirty six Fiber Optic Braggs Grating sensors were used during an ambient temperature hydrostatic pressurization testing of a Space Transportation System (STS) 40-inch Kevlar Composite Over-wrapped Pressure Vessel (COPV). The 40-inch vessel was of the same design and approximate age as the STS Main Propulsion System (MPS) and Orbiter Maneuvering System (OMS) vessels. The sensors were surfaces mounted to on the vessel to measure strain during a stress rupture event. The Bragg signals were linear with the applied pressure. The results indicated that the vessel was under an uneven force distribution at various locations on the vessel.

  17. Torsion measurement by using FBG sensors

    NASA Astrophysics Data System (ADS)

    Tian, Xiaogeng; Tao, Xiaoming

    2000-05-01

    In this paper we studied the potential of using FBG strain sensors to measure the torsion deformation theoretically and experimentally. FBG strain sensors are bonded on the surface of a shaft. When the shaft under torsion there is strain induced in the FBG sensor and the Bragg wavelength will shift accordingly. According to the wavelength shift and photoelastic properties of the FBG sensor bonded on the shaft the torsion deformation of the shaft can be obtained. In order to minimize the measurement error the optimal direction of the FBG sensor was obtained. The influence of the orientation deviation of the FBG sensor was discussed in detail. The feasibility of this method is demonstrated by experiment and the test results agree with the theoretical analysis very well.

  18. Design and proposal of dual line-of-defense perimeter watchdog incorporating optimally designed FBG based accelerometers and strain sensors using single optical fiber

    NASA Astrophysics Data System (ADS)

    Khan, Mohd. Mansoor; Sonkar, Ramesh Kumar

    2015-06-01

    Paper presents Opto-Mechanical intrusion sensor fence with FBGs attached to mechanical accelerometers and strain sensors, optimized on SolidWorks 2013 for desired frequency to 35 Hz, picking up accelerations/ strains and its deployment for perimeter security. The accelerometer structure consists of inertial mass supported by an L-shaped modified cantilever beam having non-uniform cross section area connected to base by a thin neck element which acts as strain concentrated centre hence an optimum zone for FBG sensors placement. Bragg wavelength shifts were obtained on Optigrating software for the obtained strain values on mechanical assembly of fence. CFD wind analysis is performed on the assembly to obtain the spot for accelerometer's placement to avoid false alarms up to wind velocities of 20 m/s.

  19. DFB fiber laser static strain sensor based on beat frequency interrogation with a reference fiber laser locked to a FBG resonator.

    PubMed

    Huang, Wenzhu; Feng, Shengwen; Zhang, Wentao; Li, Fang

    2016-05-30

    We report on a high-resolution static strain sensor developed with distributed feedback (DFB) fiber laser. A reference FBG resonator is used for temperature compensation. Locking another independent fiber laser to the resonator using the Pound-Drever-Hall technique results in a strain power spectral density better than Sε(f) = (4.6 × 10-21) ε2/Hz in the frequency range from 1 Hz to 1 kHz, corresponding to a minimum dynamic strain resolution of 67.8 pε/√Hz. This frequency stabilized fiber laser is proposed to interrogate the sensing DFB fiber laser by the beat frequency principle. As a reasonable DFB fiber laser setup is realized, a narrow beat frequency line-width of 3.23 kHz and a high beat frequency stability of 0.036 MHz in 15 minutes are obtained in the laboratory test, corresponding to a minimum static strain resolution of 270 pε. This is the first time that a sub-0.5 nε level for static strain measurement using DFB fiber laser is demonstrated.

  20. DFB fiber laser static strain sensor based on beat frequency interrogation with a reference fiber laser locked to a FBG resonator.

    PubMed

    Huang, Wenzhu; Feng, Shengwen; Zhang, Wentao; Li, Fang

    2016-05-30

    We report on a high-resolution static strain sensor developed with distributed feedback (DFB) fiber laser. A reference FBG resonator is used for temperature compensation. Locking another independent fiber laser to the resonator using the Pound-Drever-Hall technique results in a strain power spectral density better than Sε(f) = (4.6 × 10-21) ε2/Hz in the frequency range from 1 Hz to 1 kHz, corresponding to a minimum dynamic strain resolution of 67.8 pε/√Hz. This frequency stabilized fiber laser is proposed to interrogate the sensing DFB fiber laser by the beat frequency principle. As a reasonable DFB fiber laser setup is realized, a narrow beat frequency line-width of 3.23 kHz and a high beat frequency stability of 0.036 MHz in 15 minutes are obtained in the laboratory test, corresponding to a minimum static strain resolution of 270 pε. This is the first time that a sub-0.5 nε level for static strain measurement using DFB fiber laser is demonstrated. PMID:27410147

  1. Adherence characteristics of attaching and effacing strains of Escherichia coli from rabbits.

    PubMed Central

    Robins-Browne, R M; Tokhi, A M; Adams, L M; Bennett-Wood, V; Moisidis, A V; Krejany, E O; O'Gorman, L E

    1994-01-01

    Twelve strains of Escherichia coli previously reported to cause diarrhea in rabbits were examined for properties associated with virulence. Ten strains met the criteria for classification as enteropathogenic E. coli in that they were diarrheagenic strains that evoked attaching-effacing lesions in the small intestine and did not produce detectable enterotoxins or cytotoxins. These bacteria exhibited a variety of patterns when investigated for adherence to HEp-2 epithelial cells. Although several strains displayed localized and/or diffuse adherence to epithelial cells, they did not hybridize with DNA probes that recognize the genes responsible for these phenotypes in diarrheagenic E. coli from humans. The bacteria also varied in their ability to bind to erythrocytes and intestinal brush borders from various animal species. Six strains adhered to rabbit brush borders; two of these also adhered to brush borders from other animals. Two strains that did not adhere to rabbit brush borders adhered to those from guinea pigs or sheep. Only one of the strains investigated carried AF/R1 fimbriae, which are believed to govern the host specificity of this category of diarrheagenic E. coli. This strain was E. coli RDEC-1, which remains the only E. coli strain to date that is known to carry fimbriae of this type. The results indicate that although diarrheagenic E. coli strains from rabbits may have common properties associated with the ability to produce attaching-effacing lesions, they differ from each other and from enteropathogenic E. coli of humans in terms of some of the adhesins that mediate binding to eukaryotic cells. Images PMID:8168918

  2. Adherence of Staphylococcus aureus slime-producing strain variants to biomaterials used in orthopaedic surgery.

    PubMed

    Gracia, E; Fernández, A; Conchello, P; Laclériga, A; Paniagua, L; Seral, F; Amorena, B

    1997-01-01

    The adherence of Staphylococcus aureus to biomaterials used in orthopaedic surgery (polymethylmethacrylate, fresh bone, steel and titanium alloys) and to glass was studied in vitro at 1, 2, 6, 24 and 48 h of incubation. Nonslime-producing strains (72, 80 and 510) and slime-producing variants of these strains were used. An automated and fast method of ATP-bioluminiscence was applied to determine bacterial viability. The lowest adherence corresponded to polymethylmethacrylate and bone, and the highest to metals. Significant adherence was detected in all cases after 6 h and was strain dependent, being lowest for strain 72. In most cases, adherence of nonslime-producing variants was not significant compared with controls, and slime-producing were more adherent than nonslime-producing variants. These differences were maximal at 6 h or 48 h, depending on the strain and the material. The findings suggest that the appearance of slime-producing cells within a given nonslime-producing bacterial population may jeopardise postoperative immune systems and antibiotic efficacy as a consequence of biofilm formation on implants and prostheses.

  3. Effects of saliva or serum coating on adherence of Streptococcus oralis strains to titanium.

    PubMed

    Dorkhan, Marjan; Chávez de Paz, Luis E; Skepö, Marie; Svensäter, Gunnel; Davies, Julia R

    2012-02-01

    The use of dental implants to treat tooth loss has increased rapidly over recent years. 'Smooth' implants showing high long-term success rates have successively been replaced by implants with rougher surfaces, designed to stimulate rapid osseointegration and promote tissue healing. If exposed in the oral cavity, rougher surfaces may promote bacterial adhesion leading to formation of microbial biofilms which can induce peri-implant inflammation. Streptococcus oralis is an early colonizer of oral surfaces and has been recovered from titanium surfaces in vivo. The purpose of this study was to examine the adherence of clinical strains of S. oralis to titanium with smooth or moderately rough surface topography and to determine the effect of a saliva- or serum-derived coating on this process. Adherence was studied using a flow-cell system with confocal laser scanning microscopy, while putative adhesins were analysed using proteomics of bacterial cell wall proteins. This showed that adherence to moderately rough surfaces was greater than to smooth surfaces. Serum did not promote binding of any of the studied S. oralis strains to titanium, whereas a saliva coating increased adherence in two of three strains tested. The higher level of adherence to the moderately rough surfaces was maintained even in the presence of a saliva coating. The S. oralis strains that bound to saliva expressed an LPXTG-linked protein which was not present in the non-adherent strain. Thus strains of S. oralis differ in their capacity to bind to saliva-coated titanium and we propose that this is due to differential expression of a novel adhesin. PMID:22075030

  4. Relative adherence of Bacteroides species and strains to Actinomyces viscosus on saliva-coated hydroxyapatite

    SciTech Connect

    Li, J.; Ellen, R.P. )

    1989-09-01

    The study was designed to compare the adherence of several Bacteroides species to A. viscosus. Using 3H, we labeled 24 laboratory strains, including 13 Bacteroides species and 11 fresh clinical isolates of three Bacteroides species. Their adherence to A. viscosus bound to a saliva-coated mineral surface was quantified by liquid scintillation. Adherence relative to a standard strain, B. gingivalis 2561, was compared. Among the lab bacteroides, those of B. gingivalis (eight strains) were the greatest binders (mean, 80.5 {plus minus} 12.4%). Strains of other lab bacteroides bound less well (mean, 33.4 {plus minus} 6.3%). The difference in means was statistically significant (p less than 0.01). The mean for B. gingivalis strains was also significantly greater than that for strains of B. intermedius (51.7 {plus minus} 6.2%). Attachment of B. gingivalis was saturable in experiments in which either input concentration or time was the independent variable, indicating that B. gingivalis cells do not accumulate in this vitro simulation of plaque formation by binding to each other. Subculture did not seem to affect the degree of binding.

  5. A mechanical method to tuning a FBG-PZT voltage sensor

    NASA Astrophysics Data System (ADS)

    Ribeiro, Bessie A.; Werneck, Marcelo M.

    2015-09-01

    When using a Fiber Bragg Grating (FBG) for strain measurements it is always necessary to compensate the FBG against temperature fluctuations. In this paper it is shown an innovative method for mechanically compensating an FBG in a high voltage measurement application using an FBG-PZT sensor. The system takes advantage of a mechanical assembly that, as the PZT displaces, the screw where the FBG is bonded on displace in the opposite direction, keeping the FBG length constant. A theoretical analysis is done and experimental results are shown.

  6. Complete Genome Sequence of Crohn's Disease-Associated Adherent-Invasive E. coli Strain LF82

    PubMed Central

    de Vallée, Amélie; Dossat, Carole; Vacherie, Benoit; Zineb, El Hajji; Segurens, Beatrice; Barbe, Valerie; Sauvanet, Pierre; Neut, Christel; Colombel, Jean-Frédéric; Medigue, Claudine; Mojica, Francisco J. M.; Peyret, Pierre; Bonnet, Richard; Darfeuille-Michaud, Arlette

    2010-01-01

    Background Ileal lesions of Crohn's disease (CD) patients are abnormally colonized by pathogenic adherent-invasive Escherichia coli (AIEC) able to invade and to replicate within intestinal epithelial cells and macrophages. Principal Findings We report here the complete genome sequence of E. coli LF82, the reference strain of adherent-invasive E. coli associated with ileal Crohn's disease. The LF82 genome of 4,881,487 bp total size contains a circular chromosome with a size of 4,773,108 bp and a plasmid of 108,379 bp. The analysis of predicted coding sequences (CDSs) within the LF82 flexible genome indicated that this genome is close to the avian pathogenic strain APEC_01, meningitis-associated strain S88 and urinary-isolated strain UTI89 with regards to flexible genome and single nucleotide polymorphisms in various virulence factors. Interestingly, we observed that strains LF82 and UTI89 adhered at a similar level to Intestine-407 cells and that like LF82, APEC_01 and UTI89 were highly invasive. However, A1EC strain LF82 had an intermediate killer phenotype compared to APEC-01 and UTI89 and the LF82 genome does not harbour most of specific virulence genes from ExPEC. LF82 genome has evolved from those of ExPEC B2 strains by the acquisition of Salmonella and Yersinia isolated or clustered genes or CDSs located on pLF82 plasmid and at various loci on the chromosome. Conclusion LF82 genome analysis indicated that a number of genes, gene clusters and pathoadaptative mutations which have been acquired may play a role in virulence of AIEC strain LF82. PMID:20862302

  7. Studies on deformation/pore pressure coupling processes at Japanese URLs and the development of ultra-high resolution FBG strain sensors for rock mechanics (Invited)

    NASA Astrophysics Data System (ADS)

    Tokunaga, T.; Matsui, H.; Zuyuan, H.; Kashiwai, Y.

    2009-12-01

    with the opposite side of the fault. The transient increase of pore pressure by pumping activity is intuitively thought to be opposite in the polarity of change, however, it is interpreted to be related to the coupling process between deformation of rock masses and the change of pore pressure. Our numerical simulation supports our interpretation based on the deformation/pore pressure coupling process. This result strongly suggests that spatially high-density, high-resolution strain measurements together with pore pressure measurements in the subsurface can provide us quite exciting information on the behavior of rock mass deformation and fluid flow processes in the subsurface environments. For this purpose, we have started our new project on the development of multiplexed, high-accuracy, Fiber Bragg Grating (FBG) strain sensors for geo-engineering application. The target specifications are 10 nanostrain in strain resolution, 10 to 100 m in total length, 0.1 to 1 m in spatial resolution, and 10 to 100 in measurement points. We expect to finish this development in JFY 2011 and are hoping to deploy our sensors to both Mizunami in Japan and Homestake in US very near future.

  8. Use of bovine primary mammary epithelial cells for the comparison of adherence and invasion ability of Staphylococcus aureus strains.

    PubMed

    Hensen, S M; Pavicić, M J; Lohuis, J A; Poutrel, B

    2000-03-01

    Adherence and invasion of epithelial cells are thought to play a role in the pathogenesis of Staphylococcus aureus mastitis. A cell culture model with primary mammary epithelial cells originating from the secretory tissue from the bovine udder was used to study adherence and invasion of S. aureus. The cells were characterized with antibodies against several cell markers that had been validated on histologic cryostat sections of bovine mammary tissue. All cells stained positively with the anticytokeratin antibodies, which are restricted to epithelial cells. The cell cultures contained a small number of alpha-smooth-muscle-actin positive cells (< 1%), probably myoepithelial cells. The use of bovine primary mammary epithelial cells and bovine S. aureus isolates, which were cultured in milk serum, results in a system similar to in vivo. Strain differences for adherence and invasion of S. aureus strains cultured in milk serum were studied. In addition, the correlation between adherence and invasion was evaluated. The number of adhered and invaded bacteria was strain dependent. The percentage of adherence after 5 min of incubation was correlated to the percentage of adherence after 3 h of incubation (r = 0.94; Pearson's correlation test). Fourteen of the 20 strains were able to invade epithelial cells. The percentage of invasion was correlated to the percentage of adherence after 5 min and to the percentage adherence after 3 h (r = 0.95 and 0.90, respectively; Pearson's correlation test). Results indicate that strain differences of adherence and invasion exist for S. aureus and that the invasion is a post adherence event.

  9. Guided wave damage detection with PZT-FBG sensing

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoyi; Tian, Zhenhua; Lin, Bin; Yu, Lingyu

    2016-04-01

    This paper presents guided waves based damage detection by using a hybrid PZT actuator and optic fiber Bragg grating (FBG) sensors. In the hybrid sensing, a piezoelectric wafer (PZT) is used to generate incident guided waves based on the piezoelectric principle. Meanwhile, multiple fiber Bragg grating sensors (FBG) are adopted as receivers to measure the high-frequency small-strain guided waves base on the full width half maximum (FWHM) principle. If the inspected structure has damage such as hole, crack and notch, the incident guided waves will be reflected or scattered by the damage. Through multiple FBG sensors at different locations, the damage induced waves can be acquired and further processed for damage detection. In this research, two configurations are explored, the rosette and line arrangements of multiple sensors. The sensing and wave source localization on aluminum plate are demonstrated. The results show that wave source can be successfully detected by using both the FBG rosette and the FBG array.

  10. Adherence of gram-positive and gram-negative bacterial strains to human lung fibroblasts in vitro.

    PubMed

    Martin, D; Mathieu, L G; Lecomte, J; deRepentigny, J

    1986-01-01

    The adherence to eukaryotic cells of Escherichia coli, Neisseria gonorrhoeae, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis and the yeast Candida albicans was studied by light microscopy with an in vitro micromethod involving different cell lines. The method is inexpensive, consumes little time and material, and is reproducible. It was used to show that the gram-positive Cowan I strain of S. aureus, which naturally forms protein A on its surface, adheres in much larger numbers to human lung fibroblasts than the protein A-free Wood 46 strain, the strain of S. epidermidis, and the encapsulated Smith strain. The presence of a capsule on the latter strain apparently prevented its attachment to the fibroblasts. Among the gram-negative species studied, a piliated clinical isolate of N. gonorrhoeae, displaying the opaque colonial phenotype, adhered in larger numbers than another isolate lacking pili and displaying the transparent phenotype. E. coli K12 attached slightly to the cell line, whereas P. aeruginosa adhered to it moderately. One strain of C. albicans tested did not attach in any detectable numbers. No clear correlation between bacterial cell surface hydrophobicity, as evaluated by the hexadecane assay, and adherence to eukaryotic cells could be demonstrated for these microorganisms. With our method, bacterial attachment proceeded best at 37 degrees C and did not require more than 1 h of contact with the cell monolayer. The method described revealed differences in the adherence to eukaryotic cells, not only among species, but also between strains of the same species.

  11. Diffusely Adhering Escherichia coli Strains Induce Attaching and Effacing Phenotypes and Secrete Homologs of Esp Proteins

    PubMed Central

    Beinke, Christina; Laarmann, Sven; Wachter, Clemens; Karch, Helge; Greune, Lilo; Schmidt, M. Alexander

    1998-01-01

    Recent epidemiological studies indicate that Escherichia coli strains which exhibit the diffuse-adherence phenotype (DAEC strains) represent a potential cause of diarrhea in infants. We investigated the interaction of DAEC strains isolated from diarrhea patients in Brazil and in Germany with epithelial cells in tissue culture. The investigated strains were identified as DAEC strains by (i) their attachment pattern, (ii) presence of genes associated with the Dr family of adhesins, and (iii) lack of genetic markers for other diarrhea-associated E. coli categories. Several clinical DAEC isolates were shown to secrete similar patterns of proteins into tissue culture medium. Protein secretion was found to be regulated by environmental parameters, namely, medium, temperature, pH, and iron concentration. DAEC strains secreting these proteins induced accumulation of actin and tyrosine-phosphorylated proteins at sites of bacterial attachment, leading to the formation of pedestals and/or extended surface structures. These changes were phenotypically similar to the attaching and effacing (A/E) lesions observed with enteropathogenic and some enterohemorrhagic E. coli strains carrying the locus of enterocyte effacement (LEE) pathogenicity island. Proteins homologous to the EspA, EspB, and EspD proteins, necessary for signal transduction events inducing A/E lesions, were identified by sequence analysis and cross-reaction of specific antibodies. However, initially nonadhering strains secreting these proteins induced signal transduction events only after prolonged infection. These results indicate that secretion of the Esp proteins alone is not sufficient for efficient signal transduction. This study further shows that some DAEC strains are likely to contain a homolog(s) of the LEE locus which may contribute to the pathogenic potential of DAEC. PMID:9453606

  12. Capacity of Listeria monocytogenes Strains from the 2011 Cantaloupe Outbreak To Adhere, Survive, and Grow on Cantaloupe.

    PubMed

    Martinez, Mira Rakic; Osborne, Jason; Jayeola, Victor Oladimeji; Katic, Vera; Kathariou, Sophia

    2016-05-01

    The 2011 listeriosis outbreak attributed to whole cantaloupe involved several genetically distinct strains of serotypes 1/2a and 1/2b that had not been previously reported in invasive listeriosis outbreaks. Here we investigated the potential of strains from the 2011 cantaloupe outbreak to adhere, survive, and grow on cantaloupe rind and flesh and in juice extracted from cantaloupe at different temperatures (4, 8, and 25°C). All strains were able to adhere and grow, with ∼10-fold increases after 7 days at 4 or 8°C and after 24 h at 25°C, with a propensity for more growth on rind than on flesh or in extract. No significant differences in growth potential were noted among the different strains or between them and unrelated strains from other listeriosis outbreaks involving celery, deli meats, or hot dogs. Similarly to the cantaloupe outbreak strains, these other strains exhibited greater propensity for growth on rind than on flesh or in extract. Rinsing of cantaloupe fragments in sterile water resulted in temporary reductions of the populations by 50- to 100-fold, suggesting the potential of such washing to reduce risk if the produce is promptly consumed. The absence of marked differences in adherence or growth between the cantaloupe outbreak strains and strains from other outbreaks highlights the need to further characterize the 2011 cantaloupe outbreak strains and elucidate potential biological attributes that contributed to their implication in the outbreak. PMID:27296422

  13. In vitro probiotic characterization of Lactobacillus strains from fermented radish and their anti-adherence activity against enteric pathogens.

    PubMed

    Damodharan, Karthiyaini; Palaniyandi, Sasikumar Arunachalam; Yang, Seung Hwan; Suh, Joo-Won

    2015-11-01

    In this study, we evaluated the probiotic properties of Lactobacillus plantarum, Lactobacillus pentosus, and Lactobacillus fermentum strains isolated from fermented radish. All the strains survived the simulated oro-gastrointestinal transit condition and showed significantly higher adherence to Caco-2 cells compared with the probiotic strain Lactobacillus rhamnosus GG. The strains showed broad-spectrum antimicrobial activity, autoaggregation, and coaggregation capacity with pathogens. Furthermore, the Lactobacillus strains inhibited the adherence of Yersinia enterocolitica subsp. enterocolitica, Shigella boydii, and Salmonella choleraesuis to the Caco-2 cell line. The strains possessed bile salt hydrolase activity and their cholesterol-lowering activity in vitro was above 50% in the presence of bile. Strains of L. plantarum and L. pentosus possessed the plantaricin-encoding plnEF gene. In addition, the Lactobacillus strains maintained about 80% cell viability after freeze-drying in the presence of a combination of 5% skim milk and 5% maltodextrin as cryoprotectant, and 70% recovery of cell viability was observed in the absence of any cryoprotectant.

  14. A tip deflection calculation method for a wind turbine blade using temperature compensated FBG sensors

    NASA Astrophysics Data System (ADS)

    Choi, Ki-Sun; Huh, Yong-Hak; Kwon, Il-Bum; Yoon, Dong-Jin

    2012-02-01

    The tip deflections of wind turbine blades should be monitored continuously to prevent catastrophic failures of wind turbine power plants caused by blades hitting the tower. In this paper, a calculation method for wind turbine blade tip deflection is proposed using a finite difference method based on arbitrary beam bending and moment theory using measured strains. The blade strains were measured using fiber optic Bragg grating sensors. In order to confirm this method, a 100 kW composite wind turbine blade was manufactured with epoxy molded fiber optic Bragg grating (FBG) sensors installed in the shear web of the blade. A number of these sensors, normal FBG probes, were fabricated to only measure strains and the other sensors, temperature compensated FBG probes, were prepared to also measure strain and temperature. Because the output signals of FBG sensors are dependent on strains as well as temperatures, the sensor output signals should be compensated by the temperatures to obtain accurate strains. These FBG sensors were attached on the lower and upper parts of the web at one meter intervals throughout the entire length of the blade. To evaluate the measurement accuracy of the FBG sensors, conventional electrical strain gauges were also bonded onto the surface of the web beside each FBG sensor. By performing a static load test of the blade, the calculated tip deflection of the blade was well determined within an average error of 2.25%.

  15. A comparison of adherence by four strains of Staphylococcus intermedius and Staphylococcus hominis to canine corneocytes collected from normal dogs and dogs suffering from atopic dermatitis.

    PubMed

    McEwan, N A; Kalna, G; Mellor, D

    2005-06-01

    The aim of this study was to compare the adherence of four strains of Staphylococcus intermedius and a single strain of Staphylococcus hominis to corneocytes from both normal dogs and dogs suffering from atopic dermatitis. Cells from the skin surface, corneocytes, were collected from 10 normal dogs and 10 dogs suffering from atopic dermatitis. Four strains of S. intermedius, three isolated from canine pyoderma skin lesions (strains A, B and C), and one isolated form from canine synovial membrane sample from a case of septic arthritis (strain D) were compared. S. hominis, which is not normally associated with canine disease, was also evaluated for its ability to adhere to canine corneocytes. S. hominis did not adhere to canine corneocytes. All four strains of S. intermedius adhered well to canine corneocytes collected from both normal and atopic dogs. All strains of S. intermedius showed statistically greater adherence to corneocytes collected from atopic dogs compared with those collected from normal dogs. It was concluded that the adherence assay employed here showed that S. hominis does not adhere to canine corneocytes, S. intermedius adheres preferentially to atopic corneocytes.

  16. Susceptibility of adherent organisms from Pseudomonas aeruginosa and Staphylococcus aureus strains isolated from burn wounds to antimicrobial agents.

    PubMed

    Trafny, E A

    1998-08-01

    To assess the bactericidal effects of ciprofloxacin, netilymicin, and polymyxin B on adherent Pseudomonas aeruginosa organisms and also the bactericidal effects of ciprofloxacin, vancomycin and teicoplanin on adherent Staphylococcus aureus cells, a simple end-point microplate assay, based on the method described by Miyake et al. was used in the present study. As results of the assay, the minimal inhibitory concentration (MICADH) values are taken, which express the susceptibility of the bacterial cells spontaneously released from the surface of adherent microcolonies to antimicrobial agents. Also, a minimal bactericidal concentration (MBCADH) value was read, which is defined as the lowest antibiotic concentration required to kill the sessile bacterial cells. For twenty P. aeruginosa strains and nineteen S. aureus strains isolated from burn wounds, an enhanced resistance against bactericidal action of the applied antibiotics was observed when bacterial cells were attached to polystyrene surface. The MICADH values were comparable with the conventional MIC values only for ciprofloxacin and netilmicin for P. aeruginosa strains. The MBCADH values exceeded many times the conventional MBC values for the majority of strains. The validity of the assay was estimated in the experiment designed to determine the concentration of ciprofloxacin that should be released topically from the collagen dressing to prevent the biomaterial from microbial colonization and allow the decontamination of the wound.

  17. Serotype, antimicrobial resistance, and adherence properties of Escherichia coli strains associated with outbreaks of diarrheal illness in children in the United States.

    PubMed Central

    Moyenuddin, M; Wachsmuth, I K; Moseley, S L; Bopp, C A; Blake, P A

    1989-01-01

    Since most recorded outbreaks of diarrhea in U.S. infants attributed to Escherichia coli occurred before currently available pathogenicity assays existed, we examined the characteristics of nonenterotoxigenic E. coli strains isolated from 50 outbreaks of diarrheal disease in U.S. infants between 1934 and 1987. We assayed the strains for enteropathogenic E. coli (EPEC) serotype, localized adherence (LA) and diffuse adherence to tissue cultures, the presence of EPEC adherence factor genes, Shiga-like (Vero) toxin production, and antimicrobial resistance. EPEC serotypes were identified in 28 outbreaks (56%). LA to HeLa cells was found in 23 outbreak strains and correlated 100% with the EPEC adherence factor probe. LA was observed in 21 of 28 EPEC and 2 of 22 non-EPEC strains; however, 5 of 23 strains that were LA positive for HeLa cells did not adhere to HEp-2 or HL cells. One strain was diffuse adherence positive, and none was Shiga-like toxin positive. Multiple resistance was common in EPEC (64%), LA-positive (74%), and LA-positive EPEC (76%) strains but not in others (10%). EPEC serotypes or LA was found in 60% (n = 30) of the outbreak strains. The remaining E. coli strains may represent nonpathogenic normal flora, as-yet-undefined pathogens, or pathogens that have lost virulence-associated traits during storage or subculturing. PMID:2685024

  18. Impact of Biohybrid Magnetite Nanoparticles and Moroccan Propolis on Adherence of Methicillin Resistant Strains of Staphylococcus aureus.

    PubMed

    El-Guendouz, Soukaina; Aazza, Smail; Lyoussi, Badiaa; Bankova, Vassya; Lourenço, João P; Costa, Ana M Rosa; Mariano, José F; Miguel, Maria G; Faleiro, Maria L

    2016-01-01

    Biofilm bacteria are more resistant to antibiotics than planktonic cells. Propolis possesses antimicrobial activity. Generally, nanoparticles containing heavy metals possess antimicrobial and antibiofilm properties. In this study, the ability of adherence of Methicillin Resistant Strains of Staphylococcus aureus (MRSA) to catheters treated with magnetite nanoparticles (MNPs), produced by three methods and functionalized with oleic acid and a hydro-alcoholic extract of propolis from Morocco, was evaluated. The chemical composition of propolis was established by gas chromatography mass spectrometry (GC-MS), and the fabricated nanostructures characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Mossbauer spectroscopy and Fourrier transform infrared spectroscopy (FTIR). The capacity for impairing biofilm formation was dependent on the strain, as well as on the mode of production of MNPs. The co-precipitation method of MNPs fabrication using Fe(3+) and Na₂SO₃ solution and functionalized with oleic acid and propolis was the most effective in the impairment of adherence of all MRSA strains to catheters (p < 0.001). The adherence of the strain MRSA16 was also significantly lower (p < 0.001) when the catheters were treated with the hybrid MNPs with oleic acid produced by a hydrothermal method. The anti-MRSA observed can be attributed to the presence of benzyl caffeate, pinocembrin, galangin, and isocupressic acid in propolis extract, along with MNPs. However, for MRSA16, the impairment of its adherence on catheters may only be attributed to the hybrid MNPs with oleic acid, since very small amount, if any at all of propolis compounds were added to the MNPs. PMID:27618006

  19. Impact of Biohybrid Magnetite Nanoparticles and Moroccan Propolis on Adherence of Methicillin Resistant Strains of Staphylococcus aureus.

    PubMed

    El-Guendouz, Soukaina; Aazza, Smail; Lyoussi, Badiaa; Bankova, Vassya; Lourenço, João P; Costa, Ana M Rosa; Mariano, José F; Miguel, Maria G; Faleiro, Maria L

    2016-01-01

    Biofilm bacteria are more resistant to antibiotics than planktonic cells. Propolis possesses antimicrobial activity. Generally, nanoparticles containing heavy metals possess antimicrobial and antibiofilm properties. In this study, the ability of adherence of Methicillin Resistant Strains of Staphylococcus aureus (MRSA) to catheters treated with magnetite nanoparticles (MNPs), produced by three methods and functionalized with oleic acid and a hydro-alcoholic extract of propolis from Morocco, was evaluated. The chemical composition of propolis was established by gas chromatography mass spectrometry (GC-MS), and the fabricated nanostructures characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Mossbauer spectroscopy and Fourrier transform infrared spectroscopy (FTIR). The capacity for impairing biofilm formation was dependent on the strain, as well as on the mode of production of MNPs. The co-precipitation method of MNPs fabrication using Fe(3+) and Na₂SO₃ solution and functionalized with oleic acid and propolis was the most effective in the impairment of adherence of all MRSA strains to catheters (p < 0.001). The adherence of the strain MRSA16 was also significantly lower (p < 0.001) when the catheters were treated with the hybrid MNPs with oleic acid produced by a hydrothermal method. The anti-MRSA observed can be attributed to the presence of benzyl caffeate, pinocembrin, galangin, and isocupressic acid in propolis extract, along with MNPs. However, for MRSA16, the impairment of its adherence on catheters may only be attributed to the hybrid MNPs with oleic acid, since very small amount, if any at all of propolis compounds were added to the MNPs.

  20. Structural behavior of concrete box bridge using embedded FBG sensors

    NASA Astrophysics Data System (ADS)

    Chung, Wonseok; Kang, Donghoon

    2012-04-01

    For the structural monitoring of railway bridges, electromagnetic interference (EMI) is a significant problem as modern railway lines are powered by high-voltage electric power feeding systems. Fiber optic sensing systems are free from EMI and have been successfully applied in civil engineering fields. This study presents the application of fiber Bragg grating (FBG)-based sensing systems to precast concrete box railway bridges. A 20 m long full-scale precast concrete box railway girder was fabricated and tested in order to identify its static performance. The experimental program involved the measurement of the nonlinear static behavior until failure. Multiplexed FBG strain sensors were embedded along the length of steel rebar and a strain-induced wavelength shift was measured in order to monitor internal strains. The measured values from the FBG-based sensors are compared with the results using electric signal-based sensors. The results show that the FBG sensing system is promising and can improve the efficiency of structural monitoring for modern railway bridges.

  1. Adherence characteristics of Listeria strains isolated from three ready-to-eat meat processing plants.

    PubMed

    Kushwaha, Kalpana; Muriana, Peter M

    2009-10-01

    Over 1,560 non-food contact surface swabs and raw meat ingredient samples were collected from three ready-to-eat meat processing plants (520 from each plant) from 1998 to 1999, resulting in the recovery of 259 isolates of Listeria obtained from postprocess areas including drains, floors, garbage bins, cart wheels, walls, equipment surfaces, tables, brooms, pallet jacks, hoses, ladders, and waste chutes. We further examined 246 of the 259 isolates for adherence phenotype and used PCR to identify those that were Listeria monocytogenes. Adherence was classified as weak, moderate, or strong depending on results obtained with all Listeria isolates by using a fluorescent microplate adherence assay. Among the 246 isolates, there were 61 weakly, 148 moderately, and 37 strongly adherent Listeria, of which 130 (53%) were found to be L. monocytogenes. Plants A and B provided similar recoveries of 39 (7.5%) and 43 (8.3%) Listeria-positive isolates, including 9 (23.1% of Listeria) and 41 (95.3% of Listeria) identified as L. monocytogenes, respectively, that were weakly or moderately adherent. In plant C, we recovered 164 Listeria-positive samples (31.5% isolation rate), which included 80 L. monocytogenes-positive samples (49.8% of Listeria spp.), 52 of which were moderately adherent, as well as all 9 strongly adherent isolates of L. monocytogenes obtained in this study. Adherence properties of Listeria may allow persistence and recurrence in plant environments, potentially increasing the chance of eventual product contamination, and this emphasizes the need for sanitary approaches to prevent colonization by Listeria as well as product antimicrobial interventions should the sanitation barrier be breached.

  2. Ultra-compact strain- and temperature-insensitive torsion sensor based on a line-by-line inscribed phase-shifted FBG.

    PubMed

    Huang, Bo; Shu, Xuewen

    2016-08-01

    A novel temperature- and strain-independent optical fiber torsion sensor based on a phase-shifted fiber Bragg grating (PSFBG) inscribed by the line-by-line (LbL) technique in a standard single-mode fiber with a femtosecond laser has been proposed and experimentally demonstrated. The strong birefringence created by the LbL inscription technique leads to the significant polarization splitting of the transmission peak of the PSFBG. By simply monitoring the variation of the amplitude difference between the two polarization-peaks, the fiber torsion angle and the fiber torsion direction can be simultaneously deduced without temperature and strain confusion. The torsion sensor exhibits a high torsion sensitivity of up to -1032.71 dB/(rad/mm), with the distinct advantages of low manufacture cost, small dimension (just ~1.72mm), and extremely robust and simple structure, which make it very attractive for practical applications. To the best of our knowledge, this is the smallest torsion sensor ever reported. PMID:27505735

  3. Adaptive dynamic FBG interrogation utilising erbium-doped fibre

    NASA Astrophysics Data System (ADS)

    John, R. N.; Read, I.; MacPherson, W. N.

    2013-04-01

    A dynamic fibre Bragg grating interrogation scheme is investigated using two-wave mixing in erbium-doped fibre, capable of adapting to quasistatic strain and temperature drifts. An interference pattern set up in the erbium-doped fibre creates, due to the photorefractive effect, a dynamic grating capable of wavelength demodulating the FBG signal. The presence of a dynamic grating was verified and then dynamic strain signals from a fibre stretcher were measured. The adaptive nature of the technique was successfully demonstrated by heating the FBG while it underwent dynamic straining leading to detection unlike an alternative arrayed waveguide grating system which simultaneously failed detection. Two gratings were then wavelength division multiplexed with the signal grating receiving approximately 30dB greater signal showing that there was little cross talk in the system.

  4. Restoration of Reflection Spectra in a Serial FBG Sensor Array of a WDM/TDM Measurement System

    PubMed Central

    Hwang, Dusun; Seo, Dae-Cheol; Kwon, Il-Bum; Chung, Youngjoo

    2012-01-01

    A restoration method for reflection spectra in a serial FBG sensor array with spectral shadowing is proposed and experimentally demonstrated in a WDM/TDM combined multiplexing system. The SNR of each FBG sensor is formulated and analyzed as a function of the number and reflectivities of serial FBG sensors. The maximum number of FBG sensors in a single fiber line can be determined by the approximate formula. In the test using two FBG sensors, the restored reflection spectrum of second FBG sensor is shown to be very well matched with the original reflection spectrum. Using the proposed restoration method, the maximum peak detection error in a strain experiment is suppressed drastically by almost seven-fold, from 0.074 nm to 0.011 nm.

  5. FBG/DFB-induced chaotic self-mixing analysis and sensing applications

    NASA Astrophysics Data System (ADS)

    Tosi, Daniele

    2013-09-01

    Optical feedback induced by a highly reflective fiber Bragg grating (FBG) onto a distributed feedback (DFB) laser is investigated. In static strain conditions, the covariance matrix of the chaotic noise generated by DFB/FBG self-mixing interference is decomposed into its eigenvalues. Then, by observing the eigenvalue pattern, it is possible to detect the strain applied to FBG independently from source power and electrical noise level. Furthermore, by employing a Capon spectral estimator, and splitting and filtering out the self-mixing eigenvalues, it is possible to dynamically detect acoustic signals in harsh signal-to-noise conditions. This technique provides dual static and dynamic FBG interrogation independent on optical power and fiber link losses variations.

  6. Characterization of the Adherence of Clostridium difficile Spores: The Integrity of the Outermost Layer Affects Adherence Properties of Spores of the Epidemic Strain R20291 to Components of the Intestinal Mucosa

    PubMed Central

    Mora-Uribe, Paola; Miranda-Cárdenas, Camila; Castro-Córdova, Pablo; Gil, Fernando; Calderón, Iván; Fuentes, Juan A.; Rodas, Paula I.; Banawas, Saeed; Sarker, Mahfuzur R.; Paredes-Sabja, Daniel

    2016-01-01

    Clostridium difficile is the causative agent of the most frequently reported nosocomial diarrhea worldwide. The high incidence of recurrent infection is the main clinical challenge of C. difficile infections (CDI). Formation of C. difficile spores of the epidemic strain R20291 has been shown to be essential for recurrent infection and transmission of the disease in a mouse model. However, the underlying mechanisms of how these spores persist in the colonic environment remains unclear. In this work, we characterized the adherence properties of epidemic R20291 spores to components of the intestinal mucosa, and we assessed the role of the exosporium integrity in the adherence properties by using cdeC mutant spores with a defective exosporium layer. Our results showed that spores and vegetative cells of the epidemic R20291 strain adhered at high levels to monolayers of Caco-2 cells and mucin. Transmission electron micrographs of Caco-2 cells demonstrated that the hair-like projections on the surface of R20291 spores are in close proximity with the plasma membrane and microvilli of undifferentiated and differentiated monolayers of Caco-2 cells. Competitive-binding assay in differentiated Caco-2 cells suggests that spore-adherence is mediated by specific binding sites. By using spores of a cdeC mutant we demonstrated that the integrity of the exosporium layer determines the affinity of adherence of C. difficile spores to Caco-2 cells and mucin. Binding of fibronectin and vitronectin to the spore surface was concentration-dependent, and depending on the concentration, spore-adherence to Caco-2 cells was enhanced. In the presence of an aberrantly-assembled exosporium (cdeC spores), binding of fibronectin, but not vitronectin, was increased. Notably, independent of the exosporium integrity, only a fraction of the spores had fibronectin and vitronectin molecules binding to their surface. Collectively, these results demonstrate that the integrity of the exosporium layer of

  7. Distributed deformation measurement of large space deployable mechanism based on FBG sensors

    NASA Astrophysics Data System (ADS)

    Dong, Yanfang; Zhou, Zude; Liu, Yi; Liu, Mingyao; Li, Ruiya; Li, Tianliang

    2015-10-01

    Space deployable mechanisms are widely used, important and multi-purpose components in aerospace fields. In order to ensure the mechanism in normal situation after unfolded, detecting the deformation caused by huge temperature difference in real-time is necessary. This paper designed a deployable mechanism setup, completed its distributed deformation measurement by means of fiber Bragg grating (FBG) sensors and BP neural network, proved the mechanism distributed strain takes place sequence and FBG sensor is capable for space deployable mechanisms deformation measuring.

  8. FBG sensor for temperature-independent high sensitive pressure measurement with aid of a Bourdon tube

    NASA Astrophysics Data System (ADS)

    Srimannarayana, K.; Vengal Rao, P.; Sai Shankar, M.; Kishore, P.

    2014-05-01

    A temperature independent high sensitive pressure sensing system using fiber Bragg grating (FBG) and `C' shaped Bourdon tube (CBT) is demonstrated. The sensor is configured by firmly fixing the FBG (FBG1) between free and fixed ends of the CBT. Additional FBG (FBG2) in line to the FBG1 is introduced which is shielded from the external pressure, tend to measure only the ambient temperature fluctuations. The CBT has an elliptical cross section where its free end is sealed and the fixed end is open for subjecting the liquid or gas pressure to be measured. With the application of pressure, the free end of CBT tends to straighten out results in an axial strain in FBG1 causes red shift in Bragg wavelength. The pressure can be determined by measuring the shift of the Bragg wavelength. The experimental pressure sensitivity is found to be 66.9 pm/psi over a range of 0 to 100 psi. The test results show that the Bragg wavelength shift is linear corresponds to change in applied pressure and well agreed with the simulated results. This simple and high sensitive design is capable of measuring static/dynamic pressure and temperature simultaneously which suits for industrial applications.

  9. Activities of fosfomycin and rifampin on planktonic and adherent Enterococcus faecalis strains in an experimental foreign-body infection model.

    PubMed

    Oliva, Alessandra; Furustrand Tafin, Ulrika; Maiolo, Elena Maryka; Jeddari, Safaa; Bétrisey, Bertrand; Trampuz, Andrej

    2014-01-01

    Enterococcal implant-associated infections are difficult to treat because antibiotics generally lack activity against enterococcal biofilms. We investigated fosfomycin, rifampin, and their combinations against planktonic and adherent Enterococcus faecalis (ATCC 19433) in vitro and in a foreign-body infection model. The MIC/MBClog values were 32/>512 μg/ml for fosfomycin, 4/>64 μg/ml for rifampin, 1/2 μg/ml for ampicillin, 2/>256 μg/ml for linezolid, 16/32 μg/ml for gentamicin, 1/>64 μg/ml for vancomycin, and 1/5 μg/ml for daptomycin. In time-kill studies, fosfomycin was bactericidal at 8× and 16× MIC, but regrowth of resistant strains occurred after 24 h. With the exception of gentamicin, no complete inhibition of growth-related heat production was observed with other antimicrobials on early (3 h) or mature (24 h) biofilms. In the animal model, fosfomycin alone or in combination with daptomycin reduced planktonic counts by ≈4 log10 CFU/ml below the levels before treatment. Fosfomycin cleared planktonic bacteria from 74% of cage fluids (i.e., no growth in aspirated fluid) and eradicated biofilm bacteria from 43% of cages (i.e., no growth from removed cages). In combination with gentamicin, fosfomycin cleared 77% and cured 58% of cages; in combination with vancomycin, fosfomycin cleared 33% and cured 18% of cages; in combination with daptomycin, fosfomycin cleared 75% and cured 17% of cages. Rifampin showed no activity on planktonic or adherent E. faecalis, whereas in combination with daptomycin it cured 17% and with fosfomycin it cured 25% of cages. Emergence of fosfomycin resistance was not observed in vivo. In conclusion, fosfomycin showed activity against planktonic and adherent E. faecalis. Its role against enterococcal biofilms should be further investigated, especially in combination with rifampin and/or daptomycin treatment.

  10. Adherence to abiotic surface induces SOS response in Escherichia coli K-12 strains under aerobic and anaerobic conditions.

    PubMed

    Costa, Suelen B; Campos, Ana Carolina C; Pereira, Ana Claudia M; de Mattos-Guaraldi, Ana Luiza; Júnior, Raphael Hirata; Rosa, Ana Cláudia P; Asad, Lídia M B O

    2014-09-01

    During the colonization of surfaces, Escherichia coli bacteria often encounter DNA-damaging agents and these agents can induce several defence mechanisms. Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species (ROS) generated by chemical and physical agents or by metabolism. In this work, we have evaluated whether the interaction with an abiotic surface by mutants derived from E. coli K-12 deficient in some enzymes that are part of BER causes DNA damage and associated filamentation. Moreover, we studied the role of endonuclease V (nfi gene; 1506 mutant strain) in biofilm formation. Endonuclease V is an enzyme that is involved in DNA repair of nitrosative lesions. We verified that endonuclease V is involved in biofilm formation. Our results showed more filamentation in the xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) than in the wild-type strain (AB1157). By contrast, the mutant nfi did not present filamentation in biofilm, although its wild-type strain (1466) showed rare filaments in biofilm. The filamentation of bacterial cells attaching to a surface was a consequence of SOS induction measured by the SOS chromotest. However, biofilm formation depended on the ability of the bacteria to induce the SOS response since the mutant lexA Ind(-) did not induce the SOS response and did not form any biofilm. Oxygen tension was an important factor for the interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, our results showed that the presence or absence of oxygen did not affect the viability of BW9091 and BW535 strains. The nfi mutant and its wild-type did not exhibit decreased biofilm formation under anaerobic conditions. Scanning electron microscopy was also performed on the E. coli K-12 strains that had adhered to the glass, and we observed the presence of a structure similar to an extracellular matrix that depended on the

  11. Study on Dynamic Response Measurement of the Submarine Pipeline by Full-Term FBG Sensors

    PubMed Central

    Zhou, Jinghai; Sun, Li; Li, Hongnan

    2014-01-01

    The field of structural health monitoring is concerned with accurately and reliably assessing the integrity of a given structure to reduce ownership costs, increase operational lifetime, and improve safety. In structural health monitoring systems, fiber Bragg grating (FBG) is a promising measurement technology for its superior ability of explosion proof, immunity to electromagnetic interference, and high accuracy. This paper is a study on the dynamic characteristics of fiber Bragg grating (FBG) sensors applied to a submarine pipeline, as well as an experimental investigation on a laboratory model of the pipeline. The dynamic response of a submarine pipeline under seismic excitation is a coupled vibration of liquid and solid interaction. FBG sensors and strain gauges are used to monitor the dynamic response of a submarine pipeline model under a variety of dynamic loading conditions and the maximum working frequency of an FBG strain sensor is calculated according to its dynamic strain responses. Based on the theoretical and experimental results, it can be concluded that FBG sensor is superior to strain gauge and satisfies the demand of dynamic strain measurement. PMID:24971391

  12. A Monitoring Method Based on FBG for Concrete Corrosion Cracking.

    PubMed

    Mao, Jianghong; Xu, Fangyuan; Gao, Qian; Liu, Shenglin; Jin, Weiliang; Xu, Yidong

    2016-07-14

    Corrosion cracking of reinforced concrete caused by chloride salt is one of the main determinants of structure durability. Monitoring the entire process of concrete corrosion cracking is critical for assessing the remaining life of the structure and determining if maintenance is needed. Fiber Bragg Grating (FBG) sensing technology is extensively developed in photoelectric monitoring technology and has been used on many projects. FBG can detect the quasi-distribution of strain and temperature under corrosive environments, and thus it is suitable for monitoring reinforced concrete cracking. According to the mechanical principle that corrosion expansion is responsible for the reinforced concrete cracking, a package design of reinforced concrete cracking sensors based on FBG was proposed and investigated in this study. The corresponding relationship between the grating wavelength and strain was calibrated by an equal strength beam test. The effectiveness of the proposed method was verified by an electrically accelerated corrosion experiment. The fiber grating sensing technology was able to track the corrosion expansion and corrosion cracking in real time and provided data to inform decision-making for the maintenance and management of the engineering structure.

  13. A Monitoring Method Based on FBG for Concrete Corrosion Cracking

    PubMed Central

    Mao, Jianghong; Xu, Fangyuan; Gao, Qian; Liu, Shenglin; Jin, Weiliang; Xu, Yidong

    2016-01-01

    Corrosion cracking of reinforced concrete caused by chloride salt is one of the main determinants of structure durability. Monitoring the entire process of concrete corrosion cracking is critical for assessing the remaining life of the structure and determining if maintenance is needed. Fiber Bragg Grating (FBG) sensing technology is extensively developed in photoelectric monitoring technology and has been used on many projects. FBG can detect the quasi-distribution of strain and temperature under corrosive environments, and thus it is suitable for monitoring reinforced concrete cracking. According to the mechanical principle that corrosion expansion is responsible for the reinforced concrete cracking, a package design of reinforced concrete cracking sensors based on FBG was proposed and investigated in this study. The corresponding relationship between the grating wavelength and strain was calibrated by an equal strength beam test. The effectiveness of the proposed method was verified by an electrically accelerated corrosion experiment. The fiber grating sensing technology was able to track the corrosion expansion and corrosion cracking in real time and provided data to inform decision-making for the maintenance and management of the engineering structure. PMID:27428972

  14. A Monitoring Method Based on FBG for Concrete Corrosion Cracking.

    PubMed

    Mao, Jianghong; Xu, Fangyuan; Gao, Qian; Liu, Shenglin; Jin, Weiliang; Xu, Yidong

    2016-01-01

    Corrosion cracking of reinforced concrete caused by chloride salt is one of the main determinants of structure durability. Monitoring the entire process of concrete corrosion cracking is critical for assessing the remaining life of the structure and determining if maintenance is needed. Fiber Bragg Grating (FBG) sensing technology is extensively developed in photoelectric monitoring technology and has been used on many projects. FBG can detect the quasi-distribution of strain and temperature under corrosive environments, and thus it is suitable for monitoring reinforced concrete cracking. According to the mechanical principle that corrosion expansion is responsible for the reinforced concrete cracking, a package design of reinforced concrete cracking sensors based on FBG was proposed and investigated in this study. The corresponding relationship between the grating wavelength and strain was calibrated by an equal strength beam test. The effectiveness of the proposed method was verified by an electrically accelerated corrosion experiment. The fiber grating sensing technology was able to track the corrosion expansion and corrosion cracking in real time and provided data to inform decision-making for the maintenance and management of the engineering structure. PMID:27428972

  15. Condition monitoring of reciprocating seal based on FBG sensors

    NASA Astrophysics Data System (ADS)

    Zhao, Xiuxu; Zhang, Shuanshuan; Wen, Pengfei; Zhen, Wenhan; Ke, Wei

    2016-07-01

    The failure of hydraulic reciprocating seals will seriously affect the normal operation of hydraulic reciprocating machinery, so the potential fault condition monitoring of reciprocating seals is very important. However, it is extremely difficult because of the limitation of reciprocating motion and the structure constraints of seal groove. In this study, an approach using fiber Bragg grating (FBG) sensors is presented. Experimental results show that the contact strain changes of a reciprocating seal can be detected by FBG sensors in the operation process of the hydraulic cylinders. The failure condition of the reciprocating seal can be identified by wavelet packet energy entropy, and the center frequency of power spectrum analysis. It can provide an effective solution for the fault prevention and health management of reciprocating hydraulic rod seals.

  16. Mannitol promotes adherence of an outbreak strain of Burkholderia multivorans via an exopolysaccharide-independent mechanism that is associated with upregulation of newly identified fimbrial and afimbrial adhesins.

    PubMed

    Denman, Carmen C; Brown, Alan R

    2013-04-01

    Burkholderia multivorans, a member of the Burkholderia cepacia complex (Bcc), is an important pathogen of the cystic fibrosis (CF) lung. Mannitol, approved as an inhaled osmolyte therapy for use in CF patients, promotes exopolysaccharide (EPS) production by the Bcc. In the present study, we investigated the role of mannitol-induced EPS in the adherence of B. multivorans. We report that mannitol promoted adherence of two representative B. multivorans strains. However, whilst this enhanced adherence was largely EPS-dependent in an environmental isolate, it was EPS-independent within a CF outbreak strain, suggesting strain-to-strain variation in adhesins. Genome sequencing of the outbreak strain enabled the identification of two distinct loci encoding putative fimbrial and afimbrial adhesins. The putative fimbriae-encoding locus was found to be widely distributed amongst clinical and environmental B. multivorans. In contrast, the locus encoding the putative afimbrial adhesin (of the filamentous haemagglutinin family, FHA) was restricted to clinical isolates. Both loci contributed to biofilm formation and mucin adherence. Furthermore, we report that mannitol promoted expression of both loci, and that the locus encoding the putative FHA-family adhesin is a key determinant of the enhanced adherence observed following growth in mannitol. Our studies provide the first characterization, to our knowledge, of B. multivorans adhesins, and in so doing highlight the strain-dependent role of EPS in the Bcc and the difficulties in assigning phenotypic traits to Bcc EPS due to the wider response to mannitol. Our observations also highlight the need to monitor the microbiological effects of inhaled mannitol therapy in Bcc-infected CF patients.

  17. Feasibility study of detection of chatter by using FBG during boring

    NASA Astrophysics Data System (ADS)

    Zhu, P. Y.; Peng, W.; Yuan, L.; Hu, Z. J.

    2013-10-01

    A novel real-time monitoring system based on Fiber Bragg Grating (FBG) sensor has been developed to detect chatter in boring process. In the system, a boring bar with large length-to-diameter ratio (FSTUP3225R/L-16S) was the test subject. The FBG sensor was installed on the surface of the boring bar with the length of 225mm. A classical strain gauge was employed to measure the vibratory strain and compare the results with the ones from FBG sensor. The measurements were carried out using various cutting parameters to obtain the desired chatter phenomenon. The analysis of the experimental data was verified the chatter happened during the deep hole boring. Comparison between the experimental results from two kinds of sensors demonstrated that the measurement technique could be used to detect the dynamic strain, as well as the permitting one to research the method to identify boring chatter on-line be using optical fiber sensor system.

  18. Inverse thermoelastic analysis for thermal and mechanical loads identification using FBG data

    NASA Astrophysics Data System (ADS)

    Nakamura, Toshiya; Kamimura, Yukihiro; Igawa, Hirotaka; Morino, Yoshiki

    2014-12-01

    Fiber Bragg Grating (FBG) sensors have widely been used to monitor temperature and strain distributions as a part of the structural health monitoring system. Since FBG has the sensitivity to the variations in both temperature and strain, a compensation is required to separate the strain or temperature data from the sensor output which is the shift of the grating's Bragg wavelength. The present study develops a computational inverse thermoelastic analysis method to separately identify the thermal and mechanical boundary conditions (loads) from the output of the FBG sensor. Numerical study has been made for a corrugate-core sandwich integral thermal protection system (TPS) to examine the method. The discussion is focused on the computational stability. The results reveal that the identification of the mechanical load is less stable than that of the heat flux. It is also shown that the condition number of a coefficient matrix serves as the index of the stability of the inverse analysis.

  19. Nonintrusive FBG tube pressure transducers with high overpressure ability

    NASA Astrophysics Data System (ADS)

    Saxena, Indu F.; Hui, Kaleonui J.

    2010-04-01

    Fiber optic sensors offer several advantages over their electrical counterparts, especially for applications in hostile, spark-sensitive environments, because no electrical power is required at the sensors. In addition, the installation of fiber sensors external to fluid carrying conduits facilitates access for troubleshooting and replacement, unlike in-line diaphragm-based sensors. Furthermore, glass fiber pressure sensors have a much higher operating temperature range, which makes them more practical for flammability-prone environments. Multiple fiber Bragg grating (FBG) sensors can be multiplexed along a single fiber optic cable, as opposed to traditional resistive strain gauges, which require individual shielded metal cabling. Applications for such fiber-optic pressure detection systems include the pressure monitoring of flow in fuel lines and their pressure valves. This paper characterizes the application of FBG sensors, with remote access capability, for the nonintrusive pressure monitoring of different types of metallic pipes. We show that pressure changes smaller than one psi can be detected with a tunable diode laser-based detection system. Standard metal pipes of steel, inconel, copper-nickel alloy and titanium are characterized, and the resilience of FBG sensors to an overpressure of up to 1500 psi is demonstrated.

  20. Use of FBG sensors for health monitoring of pipelines

    NASA Astrophysics Data System (ADS)

    Felli, Ferdinando; Paolozzi, Antonio; Vendittozzi, Cristian; Paris, Claudio; Asanuma, Hiroshi

    2016-04-01

    The infrastructures for oil and gas production and distribution need reliable monitoring systems. The risks for pipelines, in particular, are not only limited to natural disasters (landslides, earthquakes, extreme environmental conditions) and accidents, but involve also the damages related to criminal activities, such as oil theft. The existing monitoring systems are not adequate for detecting damages from oil theft, and in several occasion the illegal activities resulted in leakage of oil and catastrophic environmental pollution. Systems based on fiber optic FBG (Fiber Bragg Grating) sensors present a number of advantages for pipeline monitoring. FBG sensors can withstand harsh environment, are immune to interferences, and can be used to develop a smart system for monitoring at the same time several physical characteristics, such as strain, temperature, acceleration, pressure, and vibrations. The monitoring station can be positioned tens of kilometers away from the measuring points, lowering the costs and the complexity of the system. This paper describes tests on a sensor, based on FBG technology, developed specifically for detecting damages of pipeline due to illegal activities (drilling of the pipes), that can be integrated into a smart monitoring chain.

  1. Highly sensitive contact pressure measurements using FBG patch in endotracheal tube cuff

    NASA Astrophysics Data System (ADS)

    Correia, R.; Blackman, O. R.; Hernandez, F. U.; Korposh, S.; Morgan, S. P.; Hayes-Gill, B. R.; James, S. W.; Evans, D.; Norris, A.

    2016-05-01

    A method for measuring the contact pressure between an endotracheal tube cuff and the trachea was designed and developed by using a fibre Bragg grating (FBG) based optical fibre sensor. The FBG sensor is encased in an epoxy based UV-cured cuboid patch and transduces the transversely loaded pressure into an axial strain that induces wavelength shift of the Bragg reflection. The polymer patch was created by using a PTFE based mould and increases tensile strength and sensitivity of the bare fibre FBG to pressure to 2.10×10-2 nm/kPa. The characteristics of the FBG patch allow for continuous measurement of contact pressure. The measurement of contact pressure was demonstrated by the use of a 3D printed model of a human trachea. The influence of temperature on the measurements is reduced significantly by the use of a second FBG sensor patch that is not in contact with the trachea. Intracuff pressure measurements performed using a commercial manometer agreed well with the FBG contact pressure measurements.

  2. Prototype fiber Bragg Grattings (FBG) sensor based on intensity modulation of the laser diode low frequency vibrations measurement

    NASA Astrophysics Data System (ADS)

    Setiono, Andi; Ula, Rini Khamimatul; Hanto, Dwi; Widiyatmoko, Bambang; Purnamaningsih, Retno Wigajatri

    2016-02-01

    In general, Fiber Bragg Grating (FBG) sensor works based on observation of spectral response characteristic to detect the desired parameter. In this research, we studied intensity response characteristic of FBG to detect the dynamic strain. Experiment result show that the reflected intensity had linier relationships with dynamic strain. Based on these characteristics, we developed the FBG sensor to detect low frequency vibration. This sensor is designed by attaching the FBG on the bronze cantilever with dimensions of 85×3×0.5 mm. Measurement results showed that the sensor was able to detect vibrations in the frequency range of 7-10 Hz at temperature range of 25-45 ˚C. The measured frequency range is still within the frequency range of digging activity, therefore this vibration sensor can be applied for oil pipelines vandalisation detection system.

  3. Adherence Reduction of Campylobacter jejuni and Campylobacter coli Strains to HEp-2 Cells by Mannan Oligosaccharides and a High-Molecular-Weight Component of Cranberry Extract.

    PubMed

    Ramirez-Hernandez, Alejandra; Rupnow, John; Hutkins, Robert W

    2015-08-01

    Campylobacter infections are a leading cause of human bacterial gastroenteritis in the United States and are a major cause of diarrheal disease throughout the world. Colonization and subsequent infection and invasion of Campylobacter require that the bacteria adhere to the surface of host cells. Agents that inhibit adherence could be used prophylactically to reduce Campylobacter carriage and infection. Mannan oligosaccharides (MOS) have been used as a feed supplement in livestock animals to improve performance and to replace growth-promoting antibiotics. However, MOS and other nondigestible oligosaccharides may also prevent pathogen colonization by inhibiting adherence in the gastrointestinal tract. In addition, plant extracts, including those derived from cranberries, have been shown to have antiadherence activity against pathogens. The goal of this study was to assess the ability of MOS and cranberry fractions to serve as antiadherence agents against strains of Campylobacter jejuni and Campylobacter coli. Adherence experiments were performed using HEp-2 cells. Significant reductions in adherence of C. jejuni 29438, C. jejuni 700819, C. jejuni 3329, and C. coli 43485 were observed in the presence of MOS (up to 40 mg/ml) and with a high-molecular-weight fraction of cranberry extract (up to 3 mg/ml). However, none of the tested materials reduced adherence of C. coli BAA-1061. No additive effect in adherence inhibition was observed for an MOS-cranberry blend. These results suggest that both components, MOS and cranberry, could be used to reduce Campylobacter colonization and carriage in livestock animals and potentially limit human exposure to this pathogen.

  4. Adherence Reduction of Campylobacter jejuni and Campylobacter coli Strains to HEp-2 Cells by Mannan Oligosaccharides and a High-Molecular-Weight Component of Cranberry Extract.

    PubMed

    Ramirez-Hernandez, Alejandra; Rupnow, John; Hutkins, Robert W

    2015-08-01

    Campylobacter infections are a leading cause of human bacterial gastroenteritis in the United States and are a major cause of diarrheal disease throughout the world. Colonization and subsequent infection and invasion of Campylobacter require that the bacteria adhere to the surface of host cells. Agents that inhibit adherence could be used prophylactically to reduce Campylobacter carriage and infection. Mannan oligosaccharides (MOS) have been used as a feed supplement in livestock animals to improve performance and to replace growth-promoting antibiotics. However, MOS and other nondigestible oligosaccharides may also prevent pathogen colonization by inhibiting adherence in the gastrointestinal tract. In addition, plant extracts, including those derived from cranberries, have been shown to have antiadherence activity against pathogens. The goal of this study was to assess the ability of MOS and cranberry fractions to serve as antiadherence agents against strains of Campylobacter jejuni and Campylobacter coli. Adherence experiments were performed using HEp-2 cells. Significant reductions in adherence of C. jejuni 29438, C. jejuni 700819, C. jejuni 3329, and C. coli 43485 were observed in the presence of MOS (up to 40 mg/ml) and with a high-molecular-weight fraction of cranberry extract (up to 3 mg/ml). However, none of the tested materials reduced adherence of C. coli BAA-1061. No additive effect in adherence inhibition was observed for an MOS-cranberry blend. These results suggest that both components, MOS and cranberry, could be used to reduce Campylobacter colonization and carriage in livestock animals and potentially limit human exposure to this pathogen. PMID:26219363

  5. The Adherent/Invasive Escherichia coli Strain LF82 Invades and Persists in Human Prostate Cell Line RWPE-1, Activating a Strong Inflammatory Response

    PubMed Central

    Aleandri, Marta; Marazzato, Massimiliano; Conte, Antonietta L.; Ambrosi, Cecilia; Nicoletti, Mauro; Zagaglia, Carlo; Gambara, Guido; Palombi, Fioretta; De Cesaris, Paola; Ziparo, Elio; Palamara, Anna T.; Riccioli, Anna

    2016-01-01

    Adherent/invasive Escherichia coli (AIEC) strains have recently been receiving increased attention because they are more prevalent and persistent in the intestine of Crohn's disease (CD) patients than in healthy subjects. Since AIEC strains show a high percentage of similarity to extraintestinal pathogenic E. coli (ExPEC), neonatal meningitis-associated E. coli (NMEC), and uropathogenic E. coli (UPEC) strains, here we compared AIEC strain LF82 with a UPEC isolate (strain EC73) to assess whether LF82 would be able to infect prostate cells as an extraintestinal target. The virulence phenotypes of both strains were determined by using the RWPE-1 prostate cell line. The results obtained indicated that LF82 and EC73 are able to adhere to, invade, and survive within prostate epithelial cells. Invasion was confirmed by immunofluorescence and electron microscopy. Moreover, cytochalasin D and colchicine strongly inhibited bacterial uptake of both strains, indicating the involvement of actin microfilaments and microtubules in host cell invasion. Moreover, both strains belong to phylogenetic group B2 and are strong biofilm producers. In silico analysis reveals that LF82 shares with UPEC strains several virulence factors: namely, type 1 pili, the group II capsule, the vacuolating autotransporter toxin, four iron uptake systems, and the pathogenic island (PAI). Furthermore, compared to EC73, LF82 induces in RWPE-1 cells a marked increase of phosphorylation of mitogen-activated protein kinases (MAPKs) and of NF-κB already by 5 min postinfection, thus inducing a strong inflammatory response. Our in vitro data support the hypothesis that AIEC strains might play a role in prostatitis, and, by exploiting host-cell signaling pathways controlling the innate immune response, likely facilitate bacterial multiplication and dissemination within the male genitourinary tract. PMID:27600504

  6. Genetic relatedness and virulence properties of enteropathogenic Escherichia coli strains of serotype O119:H6 expressing localized adherence or localized and aggregative adherence-like patterns on HeLa cells.

    PubMed

    Garcia, Bruna G; Ooka, Tadasuke; Gotoh, Yasuhiro; Vieira, Mônica A M; Yamamoto, Denise; Ogura, Yoshitoshi; Girão, Dennys M; Sampaio, Suely C F; Melo, Alexis Bonfim; Irino, Kinue; Hayashi, Tetsuya; Gomes, Tânia A T

    2016-05-01

    Enteropathogenic Escherichia coli (EPEC) induce attaching and effacing (A/E) lesions in enterocytes and produce the bundle-forming pilus (BFP) contributing to the localized adherence (LA) pattern formation on HeLa cells. Enteroaggregative E. coli (EAEC) produce aggregative adherence (AA) on HeLa cells and form prominent biofilms. The ability to produce LA or AA is an important hallmark to classify fecal E. coli isolates as EPEC or EAEC, respectively. E. coli strains of serotype O119:H6 exhibit an LA+ phenotype and have been considered as comprising a clonal group of EPEC strains. However, we have recently identified O119:H6 EPEC strains that produce LA and an AA-like pattern concurrently (LA/AA-like+). In this study, we evaluated the relatedness of three LA/AA-like+ and three LA+ O119:H6 strains by comparing their virulence and genotypic properties. We first found that the LA/AA-like+ strains induced actin accumulation in HeLa cells (indicative of A/E lesions formation) and formed biofilms on abiotic surfaces more efficiently than the LA+ strains. MLST analysis showed that the six strains all belong to the ST28 complex. All strains carried multiple plasmids, but as plasmid profiles were highly variable, this cannot be used to differentiate LA/AA-like+ and LA+ strains. We further obtained their draft genome sequences and the complete sequences of four plasmids harbored by one LA/AA-like+ strain. Analysis of these sequences and comparison with 37 fully sequenced E. coli genomes revealed that both O119:H6 groups belong to the E. coli phylogroup B2 and are very closely related with only 58-67 SNPs found between LA/AA-like+ and LA+ strains. Search of the draft sequences of the six strains for adhesion-related genes known in EAEC and other E. coli pathotypes detected no genes specifically present in LA/AA-like+ strains. Unexpectedly however, we found that a large plasmid distinct from pEAF is responsible for the AA-like phenotype of the LA/AA-like+ strains. Although we

  7. Early-age monitoring of cement structures using FBG sensors

    NASA Astrophysics Data System (ADS)

    Wang, Chuan; Zhou, Zhi; Zhang, Zhichun; Ou, Jinping

    2006-03-01

    With more and more broad applications of the cement-based structures such as neat cement paste, cement mortar and concrete in civil engineering, people hope to find out what their performances should like. The in-service performances of cement-based structures are highly affected by their hardening process during the early-age. But it is still a big problem for traditional sensors to be used to monitor the early curing of cement-based structures due to such disadvantages as difficulties to install sensors inside the concrete, limited measuring points, poor durability and interference of electromagnetic wave and so on. In this paper, according to the sensing properties of the Fiber Bragg Grating sensors and self-characters of the cement-based structures, we have successfully finished measuring and monitoring the early-age inner-strain and temperature changes of the neat cement paste, concrete with and without restrictions, mass concrete structures and negative concrete, respectively. Three types of FBG-based sensors have been developed to monitor the cement-based structures. Besides, the installation techniques and the embedding requirements of FBG sensors in cement-based structures are also discussed. Moreover, such kind of technique has been used in practical structure, 3rd Nanjing Yangtze Bridge, and the results show that FBG sensors are well proper for measuring and monitoring the temperature and strain changes including self-shrinkage, dry shrinkage, plastic shrinkage, temperature expansion, frost heaving and so on inside different cement-based structures. This technique provides us a new useful measuring method on early curing monitoring of cement-based structures and greater understanding of details of their hardening process.

  8. Spectra analysis of nonuniform FBG-based acousto-optic modulator by using Fourier mode coupling theory.

    PubMed

    Liu, Chao; Pei, Li; Li, Zhuoxuan; Ning, Tigang; Yu, Shaowei; Kang, Zexin

    2013-05-10

    Fourier mode coupling theory was first employed in the spectral analysis of several nonuniform fiber Bragg grating (FBG)-based acousto-optic modulators (NU-FBG-AOMs) with the effects of Gaussian-apodization (GA), phase shift (PS), and linear chirp (LC). Because of the accuracy and simplicity of the algorithm applied in this model, the modulation performances of these modulators can be acquired effectively and efficiently. Based on the model, the reflected spectra of these modulators were simulated under various acoustic frequencies and acoustically induced strains. The simulation results of the GA-FBG-AOM and PS-FBG-AOM showed that the wavelength spacing between the primary reflection peak and the secondary reflection peak is proportional to the acoustic frequency, and the reflectivity of reflection peaks depends on the acoustically induced strains. But for the LC-FBG-AOM, the wavelength spacing between the neighboring reflection peaks increased linearly and inversely with the acoustic frequency, and the extinction ratio of each peak relates to the acoustically induced strain. These numerical analysis results, which were effectively used in the designs and fabrications of these NU-FBG-AOMs, can broaden the AOM-based application scope and shed light on the performance optimization of optical wavelength-division multiplex system.

  9. Serial FBG sensor network allowing overlapping spectra

    NASA Astrophysics Data System (ADS)

    Abbenseth, S.; Lochmann, S.; Ahrens, A.; Rehm, B.

    2016-05-01

    For structure or material monitoring low impact serial fiber Bragg grating (FBG) networks have attracted increasing research interest. Common sensor networks using wavelength division multiplexing (WDM) for FBG interrogation are limited in their efficiency by the spectral width of their light source, the FBG tuning range and the spectral guard bands. Overlapping spectra are strictly forbidden in this case. Applying time division multiplexing (TDM) or active resonator schemes may overcome these restrictions. However, they introduce other substantial disadvantages like signal roundtrip dependency or sophisticated control of active resonating structures. Code division multiplexing (CDM) as a means of FBG interrogation by simple autocorrelation of appropriate codes has been shown to be superior in this respect. However, it came at the cost of a second spectrometer introducing additional equalization efforts. We demonstrate a new serial FBG sensor network utilizing CDM signal processing for efficient sensor interrogation without the need of a second spectrometer and additional state of polarization (SOP) controlling components. It allows overlapping spectra even when all sensing FBGs are positioned at the same centre wavelength and it shows a high degree of insensitivity to SOP. Sequence inversed keyed (SIK) serial signal processing utilizing quasi-orthogonal balanced codes ensures simple and quick sensor interrogation with high signal-to-interference/noise ratio.

  10. Screening of Lactobacillus strains for their ability to produce conjugated linoleic acid in milk and to adhere to the intestinal tract.

    PubMed

    Sosa-Castañeda, J; Hernández-Mendoza, A; Astiazarán-García, H; Garcia, H S; Estrada-Montoya, M C; González-Córdova, A F; Vallejo-Cordoba, B

    2015-10-01

    Conjugated linoleic acid (CLA) has been shown to provide beneficial effects on health; however, the amount consumed in food is far from that required for the desired effects. Thus, increasing the CLA content in dairy foods through milk fermentation with specific lactic acid bacteria (LAB) offers an interesting alternative. Moreover, some LAB may be able to adhere to the intestinal mucosa and produce CLA through endogenous synthesis. Therefore, the objective of this study was to screen LAB isolates for their ability to produce CLA in skim milk and in simulated gastrointestinal conditions. Additionally, the ability of selected CLA-producing LAB to adhere to the intestinal mucosa in a murine model was assessed. Results showed that of 13 strains of Lactobacillus tested, only 4 were able to produce CLA in skim milk supplemented with linoleic acid (13.44 ± 0.78 to 50.9 ± 0.26 µg/mL). Furthermore, these 4 Lactobacillus strains were able to survive and produce CLA in simulated gastrointestinal conditions and to adhere to the intestinal mucosa of Wistar rats after 7 d of oral inoculation with fluorescently labeled bacteria. Accordingly, these 4 Lactobacillus strains may be used to manufacture fermented dairy foods to increase CLA content, and consumption of these fermented milks may result in CLA produced endogenously by these LAB.

  11. Scanning and transmission electron microscopic study of adherence of Escherichia coli O103 enteropathogenic and/or enterohemorrhagic strain GV in enteric infection in rabbits.

    PubMed Central

    Licois, D; Reynaud, A; Federighi, M; Gaillard-Martinie, B; Guillot, J F; Joly, B

    1991-01-01

    The GV strain (serotype O103:H2:K-), originally isolated from a diarrheic rabbit, is an enteropathogenic Escherichia coli strain that produces diarrhea without synthesizing the classical enterotoxins and that is not invasive. This strain is characterized by a 117-kb plasmid (pREC-1). Histological study of the gut by scanning electron microscopy and transmission electron microscopy was performed on the GV strain, on a derivative strain cured of pREC-1, and on transconjugants obtained by transfer of pREC-1 to nonpathogenic strains E. coli K-12 and 6100, not belonging to the O103 serogroup. The GV strain adhered to the epithelial cells of the ileum and large intestine, whereas the cured GV strain did not. Transfer of plasmid pREC-1 to E. coli K-12 or 6100 allowed the bacteria to attach to the intestinal mucosa in the same manner as that of the wild-type GV strain. Thus, pREC-1 seems to play an important role in attachment to and colonization of the intestinal tract of rabbits by E. coli serogroup O103. Scanning electron microscopy showed numerous bacteria attached together and closely associated with intestinal villi. Transmission electron microscopy revealed effacing lesions characteristic of enteropathogenic E. coli strains: effacing of microvilli and cuplike projections (pedestal formations) associated with an acute inflammatory and hemorrhagic response. In contrast with the results reported for rabbit pathogenic O15 strains, it appeared that the Peyer's patches were not involved in the early stages of infection with the O103 GV strain. This strain may represent a model for the study of the virulence and pathogenic effects of enteropathogenic and enterohemorrhagic E. coli strains. Images PMID:1894377

  12. Detection by molecular hybridization of pap, afa, and sfa adherence systems in Escherichia coli strains associated with urinary and enteral infections.

    PubMed

    Archambaud, M; Courcoux, P; Labigne-Roussel, A

    1988-01-01

    The genetic determinants responsible for the adherence of Escherichia coli to uroepithelial cells have been identified in recent years by genetic and molecular methods. Specific DNA probes for each of the three operons which have been cloned so far (pap, afa, sfa/foc operons) have been used in colony hybridization experiments to detect the presence of each of these operons in the chromosomal DNA of 443 strains of E. coli; 186 strains were from patients with urinary tract infections (pyelonephritis, 106 strains; cystitis, 59; asymptomatic bacteriuria, 21) and 257 were strains from the stools of healthy subjects (61) or from patients with various enteral infections (196). E. coli strains harbouring the pap operon were found more frequently in the urine of patients with pyelonephritis (p less than 0.001) and cystitis (p less than 0.01) than in control stools. The presence of two operons (pap + afa) or (pap + sfa/foc) was only observed in uropathogenic strains (p less than 0.02). Pap and sfa/foc operons were never found in strains causing enteral infection; however, the afa operon was found in 7.6% of the enteropathogenic E. coli.

  13. Identification of plasmid-encoded mannose-resistant hemagglutinin and HEp-2 and HeLa cell adherence factors of two diarrheagenic Escherichia coli strains belonging to an enteropathogenic serogroup.

    PubMed Central

    Pal, R; Ghose, A C

    1990-01-01

    Two Escherichia coli strains (B/M 369 and C-35) belonging to enteropathogenic serogroup O86 were isolated from patients with infantile diarrhea and studied with respect to their cellular adherence properties. Both strains exhibited adherence (Ad+) to HEp-2 and HeLa cell monolayers in vitro and expressed mannose-resistant hemagglutinating (MRHA+) activity towards human, chicken, and sheep (but not mouse, rabbit, or guinea pig) erythrocytes. Cellular adherence properties of both strains could be substantially reduced by pronase treatment and by heat treatment (100 degrees C for 5 min) of bacteria. Electron microscopic examination failed to reveal fimbria- or pilus-like structures on the bacterial cell surface. Conjugation experiments conducted with these strains suggested that both MRHA and HEp-2 and HeLa cell adherence factors were encoded by the same plasmid, with a size of 55 to 57 megadaltons (MDa). Further biochemical studies indicated that the cellular adherence factors were associated with cell surface structures of bacteria that were proteinaceous in nature. An antiserum, rendered specific for the 57-MDa plasmid (pRP201) products of B/M 369 by adsorption, reacted with both MRHA+ Ad+ strains, B/M 369 and C-35, but not with their 57- or 55-MDa plasmidless MRHA- Ad- transconjugants or with other MRHA- Ad- E. coli strains. Immunological studies showed that the absorbed antiserum recognized two proteins with subunit molecular sizes of 18 and 14.5 kDa that were present on the cell surfaces of both strains. Furthermore, the absorbed antiserum at subagglutinating dilutions did inhibit, although only partially, the MRHA and HEp-2 and HeLa cell adherence activities of both E. coli strains. All these results would indicate that some of the E. coli strains belonging to enteropathogenic serogroups express their adherence potential through factors that were hitherto unrecognized. Images PMID:1969390

  14. Truncated enterohemorrhagic Escherichia coli (EHEC) O157:H7 intimin (EaeA) fusion proteins promote adherence of EHEC strains to HEp-2 cells.

    PubMed Central

    McKee, M L; O'Brien, A D

    1996-01-01

    Intimin, the product of the eaeA gene in enterohemorrhagic Escherichia coli O157:H7 (EHEC), is required for intimate adherence of these organisms to tissue culture cells and formation of the attaching and effacing lesion in the gnotobiotic pig. Because of the importance of intimin in the pathogenesis of EHEC O157:H7 infection in this animal model, we began a structure-function analysis of EaeA. For this purpose, we constructed amino-terminal fusions of the intimin protein with six histidine residues to form two independent fusions. The longer fusion, RIHisEae, contained 900 of the 935 predicted amino acids and included all but the extreme amino terminus. The second fusion, RVHdHisEae, consisted of the carboxyl two-thirds of the protein. Purified extracts of either construct enhanced binding of wild-type 86-24 to HEp-2 cells and conferred HEp-2 cell adherence on 86-24eaeDelta10, an eaeA deletion mutant, and B2F1, an EHEC O91:1-121 eaeA mutant strain. When 86-24eaeDelta10 was transformed with either of the plasmids encoding the intimin fusion proteins, the transformant behaved like the wild-type parent strain and displayed localized adherence to HEp-2 cells, with positive fluorescent-actin staining. In addition, polyclonal antisera raised against RIHisEae reacted with both fusion constructs and recognized an outer membrane protein of the same mass as intimin (97 kDa) in EHEC and enteropathogenic E. coli but not E. coli K-12. The intimin-specific antisera also blocked adherence of EHEC to HEp-2 cells. Thus, intimin (i) is a 97-kDa outer membrane protein in EHEC that serves as a requisite adhesin for attachment of the bacteria to epithelial cells, even when the protein is truncated by one-third at its amino terminus and (ii) can be added exogenously to specifically facilitate HEp-2 cell adherence of EHEC but not E. coli K-12. PMID:8675331

  15. Association of IL-8-inducing strains of diffusely adherent Escherichia coli with sporadic diarrheal patients with less than 5 years of age.

    PubMed

    Meraz, Ismail Mustafa; Arikawa, Kentaro; Nakamura, Hiromi; Ogasawara, Jun; Hase, Atsushi; Nishikawa, Yoshikazu

    2007-02-01

    The role of diffusely adherent Escherichia coli (DAEC) in diarrheal disease has been controversial. However, DAEC strains were recently implicated in diarrheal disease in developing countries. To clarify whether DAEC are prevalent among sporadic cases of diarrheal illness in Osaka City, Japan, E. coli strains isolated between July 1997 and March 2000 during diarrheagenic E. coli (DEC) investigation were retrospectively examined. DAEC strains were recognized among 41 (4.4%) of 924 patients and formed the biggest subgroup of DEC. Previously, we reported that some DAEC strains caused epithelial cells to secrete as much IL-8 as enteroaggregative E. coli strains did. In this study, we attempted to evaluate epidemiologically whether the ability of DAEC to induce IL-8 was involved in the pathogenesis. Relationship among patient age, symptoms, Afa adhesins, season and IL-8 induction were examined. The subgroup of DAEC that possessed Afa genes and/or induced a high level of IL-8 was significantly prevalent among patients age 1 to 4 years; however total DAEC was not significantly high among the children compared to other age group. IL-8 inducing DAEC seems to play a role in causing sporadic diarrheal illnesses, particularly in pediatric fields. Investigations highlighting the relationship between IL-8 induction and enteropathogenicity are clearly necessary to confirm the role of DAEC in infectious enteritis.

  16. The micronutrient zinc inhibits EAEC strain 042 adherence, biofilm formation, virulence gene expression, and epithelial cytokine responses benefiting the infected host.

    PubMed

    Medeiros, Pedro; Bolick, David T; Roche, James K; Noronha, Francisco; Pinheiro, Caio; Kolling, Glynis L; Lima, Aldo; Guerrant, Richard L

    2013-10-01

    Enteroaggregative Escherichia coli (EAEC) is a major pathogen worldwide, associated with diarrheal disease in both children and adults, suggesting the need for new preventive and therapeutic treatments. We investigated the role of the micronutrient zinc in the pathogenesis of an E. coli strain associated with human disease. A variety of bacterial characteristics-growth in vitro, biofilm formation, adherence to IEC-6 epithelial cells, gene expression of putative EAEC virulence factors as well as EAEC-induced cytokine expression by HCT-8 cells-were quantified. At concentrations (≤ 0.05 mM) that did not alter EAEC growth (strain 042) but that are physiologic in serum, zinc markedly decreased the organism's ability to form biofilm (P<0.001), adhere to IEC-6 epithelial cells (P<0.01), and express putative EAEC virulence factors (aggR, aap, aatA, virK) (P<0.03). After exposure of the organism to zinc, the effect on virulence factor generation was prolonged (> 3 h). Further, EAEC-induced IL-8 mRNA and protein secretion by HCT-8 epithelial cells were significantly reduced by 0.05 mM zinc (P<0.03). Using an in vivo murine model of diet-induced zinc-deficiency, oral zinc supplementation (0.4 µg/mouse daily) administered after EAEC challenge (10 (10) CFU/mouse) significantly abrogated growth shortfalls (by>90%; P<0.01); furthermore, stool shedding was reduced (days 9-11) but tissue burden of organisms in the intestine was unchanged. These findings suggest several potential mechanisms whereby physiological levels of zinc alter pathogenetic events in the bacterium (reducing biofilm formation, adherence to epithelium, virulence factor expression) as well as the bacterium's effect on the epithelium (cytokine response to exposure to EAEC) to alter EAEC pathogenesis in vitro and in vivo. These effects may help explain and extend the benefits of zinc in childhood diarrhea and malnutrition.

  17. Deflection estimation of a wind turbine blade using FBG sensors embedded in the blade bonding line

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Woo; Kang, Woo-Ram; Jeong, Min-Soo; Lee, In; Kwon, Il-Bum

    2013-12-01

    Estimating the deflection of flexible composite wind turbine blades is very important to prevent the blades from hitting the tower. Several researchers have used fiber Bragg grating (FBG) sensors—a type of optical fiber sensor (OFS)—to monitor the structural behavior of the blades. They can be installed on the surface and/or embedded in the interior of composites. However, the typical installation positions of OFSs present several problems, including delamination of sensing probes and a higher risk of fiber breakage during installation. In this study, we proposed using the bonding line between the shear web and spar cap as a new installation position of embedded OFSs for estimating the deflection of the blades. Laboratory coupon tests were undertaken preliminarily to confirm the strain measuring capability of embedded FBG sensors in adhesive layers, and the obtained values were verified by comparison with results obtained by electrical strain gauges and finite element analysis. We performed static loading tests on a 100 kW composite wind turbine blade to evaluate its deflections using embedded FBG sensors positioned in the bonding line. The deflections were estimated by classical beam theory considering a rigid body rotation near the tip of the blade. The evaluated tip deflections closely matched those measured by a linear variable differential transformer. Therefore, we verified the capability of embedded FBG sensors for evaluating the deflections of wind turbine blades. In addition, we confirmed that the bonding line between the shear web and spar cap is a practical location to embed the FBG sensors.

  18. Feeding the probiotic Enterococcus faecium strain NCIMB 10415 to piglets specifically reduces the number of Escherichia coli pathotypes that adhere to the gut mucosa.

    PubMed

    Bednorz, Carmen; Guenther, Sebastian; Oelgeschläger, Kathrin; Kinnemann, Bianca; Pieper, Robert; Hartmann, Susanne; Tedin, Karsten; Semmler, Torsten; Neumann, Konrad; Schierack, Peter; Bethe, Astrid; Wieler, Lothar H

    2013-12-01

    Feed supplementation with the probiotic Enterococcus faecium for piglets has been found to reduce pathogenic gut microorganisms. Since Escherichia coli is among the most important pathogens in pig production, we performed comprehensive analyses to gain further insight into the influence of E. faecium NCIMB 10415 on porcine intestinal E. coli. A total of 1,436 E. coli strains were isolated from three intestinal habitats (mucosa, digesta, and feces) of probiotic-supplemented and nonsupplemented (control) piglets. E. coli bacteria were characterized via pulsed-field gel electrophoresis (PFGE) for clonal analysis. The high diversity of E. coli was reflected by 168 clones. Multilocus sequence typing (MLST) was used to determine the phylogenetic backgrounds, revealing 79 sequence types (STs). Pathotypes of E. coli were further defined using multiplex PCR for virulence-associated genes. While these analyses discerned only a few significant differences in the E. coli population between the feeding groups, analyses distinguishing clones that were uniquely isolated in either the probiotic group only, the control group only, or both groups (shared group) revealed clear effects at the habitat level. Interestingly, extraintestinal pathogenic E. coli (ExPEC)-typical clones adhering to the mucosa were significantly reduced in the probiotic group. Our data show a minor influence of E. faecium on the overall population of E. coli in healthy piglets. In contrast, this probiotic has a profound effect on mucosa-adherent E. coli. This finding further substantiates a specific effect of E. faecium strain NCIMB 10415 in piglets against pathogenic E. coli in the intestine. In addition, these data question the relevance of data based on sampling fecal E. coli only.

  19. Miniature fiber Bragg grating sensor interrogator (FBG-Transceiver) system for use in aerospace and automotive health monitoring systems

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar A.; Kempen, Cornelia; Panahi, Allan; Lopatin, Craig

    2007-09-01

    Fiber Bragg grating sensors (FBGs) have gained rapid acceptance in aerospace and automotive structural health monitoring applications for the measurement of strain, stress, vibration, acoustics, acceleration, pressure, temperature, moisture, and corrosion distributed at multiple locations within the structure using a single fiber element. The most prominent advantages of FBGs are: small size and light weight, multiple FBG transducers on a single fiber, and immunity to radio frequency interference. A major disadvantage of FBG technology is that conventional state-of-the-art fiber Bragg grating interrogation systems are typically bulky and heavy bench top instruments that are assembled from off-the-shelf fiber optic and optical components integrated with a signal electronics board into an instrument console. Based on the need for a compact FBG interrogation system, this paper describes recent progress towards the development of a miniature fiber Bragg grating sensor interrogator (FBG-Transceiver TM) system based on multi-channel integrated optic sensor (InOSense) microchip technology. The hybrid InOSense microchip technology enables the integration of all of the functionalities, both passive and active, of conventional bench top FBG sensor interrogators systems, packaged in a miniaturized, low power operation, 2-cm x 5-cm small form factor (SFF) package suitable for the long-term structural health monitoring in applications where size, weight, and power are critical for operation. The sponsor of this program is NAVAIR under a DOD SBIR contract.

  20. Structural Stability Monitoring of a Physical Model Test on an Underground Cavern Group during Deep Excavations Using FBG Sensors.

    PubMed

    Li, Yong; Wang, Hanpeng; Zhu, Weishen; Li, Shucai; Liu, Jian

    2015-08-31

    Fiber Bragg Grating (FBG) sensors are comprehensively recognized as a structural stability monitoring device for all kinds of geo-materials by either embedding into or bonding onto the structural entities. The physical model in geotechnical engineering, which could accurately simulate the construction processes and the effects on the stability of underground caverns on the basis of satisfying the similarity principles, is an actual physical entity. Using a physical model test of underground caverns in Shuangjiangkou Hydropower Station, FBG sensors were used to determine how to model the small displacements of some key monitoring points in the large-scale physical model during excavation. In the process of building the test specimen, it is most successful to embed FBG sensors in the physical model through making an opening and adding some quick-set silicon. The experimental results show that the FBG sensor has higher measuring accuracy than other conventional sensors like electrical resistance strain gages and extensometers. The experimental results are also in good agreement with the numerical simulation results. In conclusion, FBG sensors could effectively measure small displacements of monitoring points in the whole process of the physical model test. The experimental results reveal the deformation and failure characteristics of the surrounding rock mass and make some guidance for the in situ engineering construction.

  1. Structural Stability Monitoring of a Physical Model Test on an Underground Cavern Group during Deep Excavations Using FBG Sensors

    PubMed Central

    Li, Yong; Wang, Hanpeng; Zhu, Weishen; Li, Shucai; Liu, Jian

    2015-01-01

    Fiber Bragg Grating (FBG) sensors are comprehensively recognized as a structural stability monitoring device for all kinds of geo-materials by either embedding into or bonding onto the structural entities. The physical model in geotechnical engineering, which could accurately simulate the construction processes and the effects on the stability of underground caverns on the basis of satisfying the similarity principles, is an actual physical entity. Using a physical model test of underground caverns in Shuangjiangkou Hydropower Station, FBG sensors were used to determine how to model the small displacements of some key monitoring points in the large-scale physical model during excavation. In the process of building the test specimen, it is most successful to embed FBG sensors in the physical model through making an opening and adding some quick-set silicon. The experimental results show that the FBG sensor has higher measuring accuracy than other conventional sensors like electrical resistance strain gages and extensometers. The experimental results are also in good agreement with the numerical simulation results. In conclusion, FBG sensors could effectively measure small displacements of monitoring points in the whole process of the physical model test. The experimental results reveal the deformation and failure characteristics of the surrounding rock mass and make some guidance for the in situ engineering construction. PMID:26404287

  2. Structural Stability Monitoring of a Physical Model Test on an Underground Cavern Group during Deep Excavations Using FBG Sensors.

    PubMed

    Li, Yong; Wang, Hanpeng; Zhu, Weishen; Li, Shucai; Liu, Jian

    2015-01-01

    Fiber Bragg Grating (FBG) sensors are comprehensively recognized as a structural stability monitoring device for all kinds of geo-materials by either embedding into or bonding onto the structural entities. The physical model in geotechnical engineering, which could accurately simulate the construction processes and the effects on the stability of underground caverns on the basis of satisfying the similarity principles, is an actual physical entity. Using a physical model test of underground caverns in Shuangjiangkou Hydropower Station, FBG sensors were used to determine how to model the small displacements of some key monitoring points in the large-scale physical model during excavation. In the process of building the test specimen, it is most successful to embed FBG sensors in the physical model through making an opening and adding some quick-set silicon. The experimental results show that the FBG sensor has higher measuring accuracy than other conventional sensors like electrical resistance strain gages and extensometers. The experimental results are also in good agreement with the numerical simulation results. In conclusion, FBG sensors could effectively measure small displacements of monitoring points in the whole process of the physical model test. The experimental results reveal the deformation and failure characteristics of the surrounding rock mass and make some guidance for the in situ engineering construction. PMID:26404287

  3. On-line structural health and fire monitoring of a composite personal aircraft using an FBG sensing system

    NASA Astrophysics Data System (ADS)

    Chandler, K.; Ferguson, S.; Graver, T.; Csipkes, A.; Mendez, A.

    2008-03-01

    We report in this paper on the design and development of a novel on-line structural health monitoring and fire detection system based on an array of optical fiber Bragg grating (FBG) sensors and interrogation system installed on a new, precommercial compact aircraft. A combined total of 17 FBG sensors - strain, temperature and high-temperature - were installed at critical locations in an around the wings, fuselage and engine compartment of a prototype, Comp Air CA 12 all-composite, ten-passenger personal airplane powered by a 1,650 hp turbine engine. The sensors are interrogated online and in real time by a swept laser FBG interrogator (Micron Optics sm125-700) mounted on board the plane. Sensors readings are then combined with the plane's avionics system and displayed on the pilot's aviation control panel. This system represents the first of its kind in commercial, small frame, airplanes and a first for optical fiber sensors.

  4. [Monitoring of Crack Propagation in Repaired Structures Based on Characteristics of FBG Sensors Reflecting Spectra].

    PubMed

    Yuan, Shen-fang; Jin, Xin; Qiu, Lei; Huang, Hong-mei

    2015-03-01

    In order to improve the security of aircraft repaired structures, a method of crack propagation monitoring in repaired structures is put forward basing on characteristics of Fiber Bragg Grating (FBG) reflecting spectra in this article. With the cyclic loading effecting on repaired structure, cracks propagate, while non-uniform strain field appears nearby the tip of crack which leads to the FBG sensors' reflecting spectra deformations. The crack propagating can be monitored by extracting the characteristics of FBG sensors' reflecting spectral deformations. A finite element model (FEM) of the specimen is established. Meanwhile, the distributions of strains which are under the action of cracks of different angles and lengths are obtained. The characteristics, such as main peak wavelength shift, area of reflecting spectra, second and third peak value and so on, are extracted from the FBGs' reflecting spectral which are calculated by transfer matrix algorithm. An artificial neural network is built to act as the model between the characteristics of the reflecting spectral and the propagation of crack. As a result, the crack propagation of repaired structures is monitored accurately and the error of crack length is less than 0.5 mm, the error of crack angle is less than 5 degree. The accurately monitoring problem of crack propagation of repaired structures is solved by taking use of this method. It has important significance in aircrafts safety improvement and maintenance cost reducing.

  5. An optimized FBG-based fatigue monitoring strategy on deepwater risers

    NASA Astrophysics Data System (ADS)

    Li, Xuan; Ren, Peng; Zhou, Zhi; Ou, Jinping

    2014-11-01

    For the sake of the increasing demands of oil and gas essential, scientists and engineers have exerted great efforts in obtaining natural resources deposited in the deep water. Risers, as the channel between platform and wellhead, play a key role in oil and gas transportation. Subjected to coarse environmental conditions and uncertain loading patterns, risers would display complex dynamic behaviors which could result in severe fatigue damages. Recently, riser response is commonly measured using passive and durable Fiber Bragg Grating (FBG) strain sensors for industry safety, especially for Integrity Management (IM). However, for technique difficulties as well as economical consideration, it is impossible to execute distributed fatigue monitoring on the whole riser, which makes it essential to find out an optimized method utilizing the least number of sensors and reconstruct the global response of risers. This paper propose a method which combines H2 norms and Kalman filter to give optimal state estimation of risers based on limited FBG-based dynamic strain information. The H2 norms are used to give guideline for optimized sensor placement. Meanwhile, Kalman filter realize the global response reconstruction of risers as well as minimize the environmental disturbance. The accuracy and efficiency of the method has been verified by a numerical case. This study provides an FBG-based early warning technique for industry application of deepwater risers in future.

  6. Monitoring the Corrosion Process of Reinforced Concrete Using BOTDA and FBG Sensors

    PubMed Central

    Mao, Jianghong; Chen, Jiayun; Cui, Lei; Jin, Weiliang; Xu, Chen; He, Yong

    2015-01-01

    Expansion and cracking induced by the corrosion of reinforcement concrete is the major factor in the failure of concrete durability. Therefore, monitoring of concrete cracking is critical for evaluating the safety of concrete structures. In this paper, we introduce a novel monitoring method combining Brillouin optical time domain analysis (BOTDA) and fiber Bragg grating (FBG), based on mechanical principles of concrete expansion cracking. BOTDA monitors concrete expansion and crack width, while FBG identifies the time and position of cracking. A water-pressure loading simulation test was carried out to determine the relationship between fiber strain, concrete expansion and crack width. An electrical accelerated corrosion test was also conducted to evaluate the ability of this novel sensor to monitor concrete cracking under practical conditions. PMID:25884790

  7. In Vivo Pattern Classification of Ingestive Behavior in Ruminants Using FBG Sensors and Machine Learning

    PubMed Central

    Pegorini, Vinicius; Karam, Leandro Zen; Pitta, Christiano Santos Rocha; Cardoso, Rafael; da Silva, Jean Carlos Cardozo; Kalinowski, Hypolito José; Ribeiro, Richardson; Bertotti, Fábio Luiz; Assmann, Tangriani Simioni

    2015-01-01

    Pattern classification of ingestive behavior in grazing animals has extreme importance in studies related to animal nutrition, growth and health. In this paper, a system to classify chewing patterns of ruminants in in vivo experiments is developed. The proposal is based on data collected by optical fiber Bragg grating sensors (FBG) that are processed by machine learning techniques. The FBG sensors measure the biomechanical strain during jaw movements, and a decision tree is responsible for the classification of the associated chewing pattern. In this study, patterns associated with food intake of dietary supplement, hay and ryegrass were considered. Additionally, two other important events for ingestive behavior were monitored: rumination and idleness. Experimental results show that the proposed approach for pattern classification is capable of differentiating the five patterns involved in the chewing process with an overall accuracy of 94%. PMID:26569250

  8. Monitoring the corrosion process of reinforced concrete using BOTDA and FBG sensors.

    PubMed

    Mao, Jianghong; Chen, Jiayun; Cui, Lei; Jin, Weiliang; Xu, Chen; He, Yong

    2015-04-15

    Expansion and cracking induced by the corrosion of reinforcement concrete is the major factor in the failure of concrete durability. Therefore, monitoring of concrete cracking is critical for evaluating the safety of concrete structures. In this paper, we introduce a novel monitoring method combining Brillouin optical time domain analysis (BOTDA) and fiber Bragg grating (FBG), based on mechanical principles of concrete expansion cracking. BOTDA monitors concrete expansion and crack width, while FBG identifies the time and position of cracking. A water-pressure loading simulation test was carried out to determine the relationship between fiber strain, concrete expansion and crack width. An electrical accelerated corrosion test was also conducted to evaluate the ability of this novel sensor to monitor concrete cracking under practical conditions.

  9. In Vivo Pattern Classification of Ingestive Behavior in Ruminants Using FBG Sensors and Machine Learning.

    PubMed

    Pegorini, Vinicius; Karam, Leandro Zen; Pitta, Christiano Santos Rocha; Cardoso, Rafael; da Silva, Jean Carlos Cardozo; Kalinowski, Hypolito José; Ribeiro, Richardson; Bertotti, Fábio Luiz; Assmann, Tangriani Simioni

    2015-01-01

    Pattern classification of ingestive behavior in grazing animals has extreme importance in studies related to animal nutrition, growth and health. In this paper, a system to classify chewing patterns of ruminants in in vivo experiments is developed. The proposal is based on data collected by optical fiber Bragg grating sensors (FBG) that are processed by machine learning techniques. The FBG sensors measure the biomechanical strain during jaw movements, and a decision tree is responsible for the classification of the associated chewing pattern. In this study, patterns associated with food intake of dietary supplement, hay and ryegrass were considered. Additionally, two other important events for ingestive behavior were monitored: rumination and idleness. Experimental results show that the proposed approach for pattern classification is capable of differentiating the five patterns involved in the chewing process with an overall accuracy of 94%. PMID:26569250

  10. Ultrasonic Sensitivity of Strain-Insensitive Fiber Bragg Grating Sensors and Evaluation of Ultrasound-Induced Strain

    PubMed Central

    Tsuda, Hiroshi; Kumakura, Kenji; Ogihara, Shinji

    2010-01-01

    In conventional ultrasound detection in structures, a fiber Bragg grating (FBG) is glued on or embedded in the structure. However, application of strain to the structure can influence the sensitivity of the FBG toward ultrasound and can prevent its effective detection. An FBG can work as a strain-insensitive ultrasound sensor when it is not directly glued to the monitored structure, but is instead applied to a small thin plate to form a mobile sensor. Another possible configuration is to affix an FBG-inscribed optical fiber without the grating section attached to the monitored structure. In the present study, sensitivity to ultrasound propagated through an aluminum plate was compared for a strain-insensitive FBG sensor and an FBG sensor installed in a conventional manner. Strains induced by ultrasound from a piezoelectric transducer and by quasi-acoustic emission of a pencil lead break were also quantitatively evaluated from the response amplitude of the FBG sensor. Experimental results showed that the reduction in the signal-to-noise ratio for ultrasound detection with strain-insensitive FBG sensors, relative to traditionally-installed FBG sensors, was only 6 dB, and the ultrasound-induced strain varied within a range of sub-micron strains. PMID:22163523

  11. Rethinking adherence.

    PubMed

    Steiner, John F

    2012-10-16

    In 2012, the Centers for Medicare & Medicaid Services (CMS) will introduce measures of adherence to oral hypoglycemic, antihypertensive, and cholesterol-lowering drugs into its Medicare Advantage quality program. To meet these quality goals, delivery systems will need to develop and disseminate strategies to improve adherence. The design of adherence interventions has too often been guided by the mistaken assumptions that adherence is a single behavior that can be predicted from readily available patient characteristics and that individual clinicians alone can improve adherence at the population level.Effective interventions require recognition that adherence is a set of interacting behaviors influenced by individual, social, and environmental forces; adherence interventions must be broadly based, rather than targeted to specific population subgroups; and counseling with a trusted clinician needs to be complemented by outreach interventions and removal of structural and organizational barriers. To achieve the adherence goals set by CMS, front-line clinicians, interdisciplinary teams, organizational leaders, and policymakers will need to coordinate efforts in ways that exemplify the underlying principles of health care reform.

  12. Spectra power and bandwidth of fiber Bragg grating under influence of gradient strain

    NASA Astrophysics Data System (ADS)

    Liu, Qinpeng; Qiao, Xueguang; Jia, Zhen'an; Fu, Haiwei

    2016-09-01

    The reflective spectrum power and the bandwidth of the fiber Bragg grating (FBG) under gradient strain are researched and experimentally demonstrated. The gradient strain is applied on the FBG, which can induce FBG bandwidth broadening, resulting in the variation of reflective power. Based on the coupled-mode theory and transfer matrix method, the segmental linear relationship between the gradient strain, the reflective power, and the bandwidth is simulated and analyzed, and the influence of the FBG length on the reflective spectrum is analyzed. In the experiment, the strict gradient stain device is designed; the experimental results indicate that the reflective optic power and the bandwidth of the FBG under gradient stain are concerned with the length of the FBG. Experimental results are well consistent with the theoretical analysis, which have important guiding significance in the FBG dynamic sensing.

  13. High resolution interrogation system for fiber Bragg grating (FBG) sensor application using radio frequency spectrum analyser

    NASA Astrophysics Data System (ADS)

    Muhammad, F. D.; Zulkifli, M. Z.; Harun, S. W.; Ahmad, H.

    2013-05-01

    In this paper, we propose a fiber Bragg grating (FBG) interrogation system for high resolution sensor application based on radio frequency (RF) generation technique by beating a single longitudinal mode (SLM) fiber ring laser with an external tunable laser source (TLS). The external TLS provides a constant wavelength (CW), functioning as the reference signal for the frequency beating technique. The TLS used has a constant output power and wavelength over time. The sensor signal is provided by the reflected wavelength of a typical fiber Bragg grating (FBG) in the SLM fiber ring laser, which consists of a 1 m long highly doped Erbium doped fiber as the gain medium. The key to ensure the SLM laser oscillation is the role of graphene as saturable absorber which is opposed to the commonly used unpumped erbiumdoped fiber and this consequently contributes to the simple and short cavity design of our proposed system. The signal from the SLM fiber ring laser, which is generated by the FBG in response to external changes, such as temperature, strain, air humidity and air movement, is heterodyned with the CW signal from the TLS at a 6 GHz photodetector using a 3-dB fused coupler to generate the frequency beating. This proposed system is experimentally demonstrated as a temperature sensor and the results shows that the frequency response of the system towards the changes in temperature is about 1.3 GHz/°C, taking into account the resolution bandwidth of 3 MHz of the radio frequency spectrum analyzer (RFSA).

  14. Research on FBG-based longitudinal-acousto-optic modulator with Fourier mode coupling method.

    PubMed

    Li, Zhuoxuan; Pei, Li; Liu, Chao; Ning, Tigang; Yu, Shaowei

    2012-10-20

    Fourier mode coupling model was first applied to achieve the spectra property of a fiber Bragg grating (FBG)-based longitudinal-acousto-optic modulator. Compared with traditional analysis algorithms, such as the transfer matrix method, the Fourier mode coupling model could improve the computing efficiency up to 100 times with a guarantee of accuracy. In this paper, based on the theoretical analysis of this model, the spectra characteristics of the modulator in different frequencies and acoustically induced strains were numerically simulated. In the experiment, a uniform FBG was modulated by acoustic wave (AW) at 12 different frequencies. In particular, the modulator responses at 563 and 885.5 KHz with three different lead zirconate titanate (PZT) loads applied were plotted for illustration, and the linear fitting of experimental data demonstrated a good match with the simulation result. The acoustic excitation of the longitudinal wave is obtained using a conic silica horn attached to the surface of a shear-mode PZT plate paralleled to the fiber axis. This way of generating longitudinal AW with a transversal PZT may shed light on the optimal structural design for the FBG-based longitudinal-acousto-optic modulator.

  15. Guided wave diagnosis in composite grid structure with embedded FBG sensors

    NASA Astrophysics Data System (ADS)

    Amano, Masataro; Arai, Takeo; Takeda, Nobuo

    2007-04-01

    The authors tried to construct a structural health monitoring (SHM) system to identify damage in composite grid structure called Advanced Grid Structure (AGS) by using two types of guided waves, compressional and flexural waves, propagating along ribs of AGS. Fiber Bragg grating (FBG) sensors network embedded in AGS is utilized as their receivers. AGS is defined as trussed structures whose ribs are made of Carbon fiber reinforced plastic (CFRP). AGS has often been applied to aerospace structures because it is structurally effective and redundant. The authors had reported one possible method of SHM of AGS by monitoring of static strain distribution with embedded FBG sensors network in AGS. In this paper, we propose another possible method of SHM of AGS. We utilized two types of guided waves, compressional and flexural waves, for damage diagnosis. First, we verified our proposed system experimentally. The results confirmed that FBG sensors could measure both elastic waves and two types of guided waves were generated with the proposed system. Then, some basic characteristics of compressional and flexural wave propagations were clarified experimentally to find that compressional wave has directionality and flexural wave has isotropy. Based on the characteristics, the authors proposed two types of damage diagnosis methods with compressional and flexural waves, respectively. Moreover, those proposed methods were applied to two specific damage types, rib crack and debonding between ribs and skin. The specific damage diagnosis methods were verified experimentally to find that damages could be detected by those methods.

  16. Validation of long-term measurements from FBG sensors

    NASA Astrophysics Data System (ADS)

    Abdel-Jaber, Hiba; Glisic, Branko

    2016-04-01

    Temperature monitoring has been of increased importance in recent years due to the need for temperature measurements in order to compensate other measurement parameters, such as strain, and the increased attention to understanding thermal behaviors of structures in order to assess their performance and condition. To ensure the accuracy of thermal compensation and study of thermal behavior, reliable long-term temperature measurements are required. In this paper, two methods that are aimed at validating long-term temperature measurements are created and their application is presented. The methods differ in the type of data they use for the purpose of validation. The first method relies on the existence of two independent temperature sensors at the same location. Validation is performed by comparing the measurements from the two sensors to one another, and discrepancies between the two data sets indicate malfunction or drift in at least one of the sensors. The second method is applicable to the more general case where only one temperature sensor is available at a given location. The method thus utilizes ambient temperature data from a nearby weather tower to validate measurements from the sensor. The two methods are applied to temperature measurements from FBG sensors installed on Streicker Bridge on the Princeton University campus. The methods successfully identified and characterized malfunction and drift in some of the sensors and confirmed stable measurements in other sensors.

  17. Isolation of an Escherichia coil strain mutant unable to form biofilm on polystyrene and to adhere to human pneumocyte cells: involvement of tryptophanase.

    PubMed

    Di Martino, P; Merieau, A; Phillips, R; Orange, N; Hulen, C

    2002-02-01

    Escherichia coli adherence to biotic and abiotic surfaces constitutes the first step of infection by promoting colonization and biofilm formation. The aim of this study was to gain a better understanding of the relationship between E. coli adherence to different biotic surfaces and biofilm formation on abiotic surfaces. We isolated mutants defective in A549 pneumocyte cells adherence, fibronectin adherence, and biofilm formation by random transposition mutagenesis and sequential passages over A549 cell monolayers. Among the 97 mutants tested, 80 were decreased in biofilm formation, 8 were decreased in A549 cells adherence, 7 were decreased in their adherence to fibronectin, and 17 had no perturbations in either of the three phenotypes. We observed a correlation between adherence to fibronectin or A549 cells and biofilm formation, indicating that biotic adhesive factors are involved in biofilm formation by E. coli. Molecular analysis of the mutants revealed that a transposon insertion in the tnaA gene encoding for tryptophanase was associated with a decrease in both A549 cells adherence and biofilm formation by E. coli. The complementation of the tnaA mutant with plasmid-located wild-type tnaA restored the tryptophanase activity, epithelial cells adherence, and biofilm formation on polystyrene. The possible mechanism of tryptophanase involvement in E. coli adherence and biofilm formation is discussed.

  18. Prospects for new antimicrobials based on N,N-dimethylbiguanide complexes as effective agents on both planktonic and adhered microbial strains.

    PubMed

    Olar, Rodica; Badea, Mihaela; Marinescu, Dana; Chifiriuc, Carmen-Mariana; Bleotu, Coralia; Grecu, Maria Nicoleta; Iorgulescu, Emilia Elena; Bucur, Marcela; Lazar, Veronica; Finaru, Adriana

    2010-07-01

    Metal-free N,N-dimethylbiguanidium acetate and novel complexes M(DMBG)(2)(CH(3)COO)(2).nH(2)O (M: Mn(II), Ni(II), Cu(II) and Zn(II)) were screened for their antimicrobial properties against Gram-positive (Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus), Gram-negative (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa) bacteria and fungal (Candida albicans) strains. The ability of compounds to inhibit the microbial adherence ability to the inert substratum as well as their cytotoxicity was also assessed. Our results are demonstrating that some of the tested compounds are exhibiting potent antimicrobial activity accompanied by low cytotoxicity on HeLa cells. The complexes were characterized using microanalytical, IR, EPR, (1)H NMR as well as UV-vis methods. The redox behaviour of complexes was investigated by cyclic voltammetry. The new derivative (HDMBG)(CH(3)COO) crystallizes in the monoclinic P2(1)/n space group as X-ray single-crystal data indicate.

  19. Monitoring diesel engine parameters based on FBG probe

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Jiang, Qi; Wang, Bao-yan; Wang, Jun-jie

    2016-09-01

    This paper proposes an unprecedented systematic approach for real-time monitoring the temperature and flow of diesel engine by using embedded fiber Bragg grating (FBG). By virtue of FBG's temperature effect, we design a novel sensitive FBG temperature sensing probe to measure the temperature of cylinder head and inlet flow of diesel engine. We also establish the corresponding software platform for intuitive data analysis. The experimental and complementary simulation results simultaneously demonstrate that the FBG-based optical fiber technique possesses extraordinary reproducibility and sensitivity, which makes it feasible to monitor the temperature and inlet flow of diesel engine. Our work can provide an effective way to evaluate the thermal load of cylinder head in diesel engine.

  20. A short baseline strainmeter using fiber-optic Bragg-Grating (FBG) sensor and a nano-optic interferometer

    NASA Astrophysics Data System (ADS)

    Coutant, O.; Demengin, M.; Le Coarer, E.; Gaffet, S.

    2013-12-01

    Strain recordings from tiltmeters or borehole volumetric strainmeters on volcanoes reveal extremely rich signal of deformation associated with eruptive processes. The ability to detect and record signals of the order of few tens of nanostrain is complementary to other monitoring techniques, and of great interest to monitor and model the volcanic processes. Strain recording remains however a challenge, for both the instrumental and the installation point of view. We present in this study the first results of strain recordings, using a new fiber-optic Bragg-Grating (FBG) sensor. FBG sensors are known for many years and used as strain gauges in civil engineering. They are however limited in this case to microstrain capability. We use here a newly developped interferometer named SWIFTS whose main characteristics are i) an extremely high optical wavelength precision and ii) a small design and low power requirements allowing an easy field deployment. Our FBG sensor uses a short baseline, 3cm long Bragg network. We show preliminary results obtained from a several months recordings in the low noise underground laboratory at Rustrel (LSBB), south of France.

  1. Design and Experiment of FBG-Based Icing Monitoring on Overhead Transmission Lines with an Improvement Trial for Windy Weather

    PubMed Central

    Zhang, Min; Xing, Yimeng; Zhang, Zhiguo; Chen, Qiguan

    2014-01-01

    A scheme for monitoring icing on overhead transmission lines with fiber Bragg grating (FBG) strain sensors is designed and evaluated both theoretically and experimentally. The influences of temperature and wind are considered. The results of field experiments using simulated ice loading on windless days indicate that the scheme is capable of monitoring the icing thickness within 0–30 mm with an accuracy of ±1 mm, a load cell error of 0.0308v, a repeatability error of 0.3328v and a hysteresis error is 0.026%. To improve the measurement during windy weather, a correction factor is added to the effective gravity acceleration, and the absolute FBG strain is replaced by its statistical average. PMID:25615733

  2. Fiber Bragg grating dynamic strain sensor using an adaptive reflective semiconductor optical amplifier source.

    PubMed

    Wei, Heming; Tao, Chuanyi; Zhu, Yinian; Krishnaswamy, Sridhar

    2016-04-01

    In this paper, a reflective semiconductor optical amplifier (RSOA) is configured to demodulate dynamic spectral shifts of a fiber Bragg grating (FBG) dynamic strain sensor. The FBG sensor and the RSOA source form an adaptive fiber cavity laser. As the reflective spectrum of the FBG sensor changes due to dynamic strains, the wavelength of the laser output shifts accordingly, which is subsequently converted into a corresponding phase shift and demodulated by an unbalanced Michelson interferometer. Due to the short transition time of the RSOA, the RSOA-FBG cavity can respond to dynamic strains at high frequencies extending to megahertz. A demodulator using a PID controller is used to compensate for low-frequency drifts induced by temperature and large quasi-static strains. As the sensitivity of the demodulator is a function of the optical path difference and the FBG spectral width, optimal parameters to obtain high sensitivity are presented. Multiplexing to demodulate multiple FBG sensors is also discussed. PMID:27139682

  3. High-speed system for FBG-based measurements of vibration and sound

    NASA Astrophysics Data System (ADS)

    Karabacak, Devrez M.; Ibrahim, Selwan K.; Koumans, Yorick; Meulblok, Bastiaan; Knoppers, Rik

    2016-05-01

    Fiber Bragg Gratings (FBGs) allow for optical detection of localized physical effects without the need to couple the light out and back into a fiber, enabling robust and multiplexed sensor systems. The need of combining wide bandwidth and high resolution for dynamic sensing applications, like acoustics and vibrations, has presented significant challenges for FBG-based solutions. Here, we present a novel FBG-based measurement system enabled by using high-speed and highprecision tunable laser-based optical interrogation scheme. Multiple levels of integrated wavelength referencing coupled with low-noise high-speed electronics allow for spectral feature tracking at a resolution of <20 fm at kHz-frequencies. In combination with fiber accelerometers that employ unique force transmission mechanisms, amplifying strain on the Bragg grating and increasing the resonance frequency of the transducer, resolutions <10 μg (150 Hz bandwidth) to submg resolution in kHz-frequencies is achieved. Similarly, compact wavelength-multiplexed hydrophones with wide range linearity and dynamic range, sub-Pa resolution and flat-sensitivity down to static pressures are demonstrated. The sensors are demonstrated to be customizable to application-specific requirements, and designed to be scalable to large quantity reproducible manufacturing. In contrast to interferometry-based solutions, the tunable swept-laser detection scheme in combination with strain-based FBG sensors provides a cost-effective system that allows for easy scaling of sensor counts per fiber with multiple fibers being simultaneously recorded. Finally, the integrated high accuracy triggering and hybrid measurement capabilities present the potential to monitor sounds and vibrations in a wide range of applications from seismic surveys to machine and structural monitoring applications in harsh environments.

  4. Multiepitope fusion antigen induces broadly protective antibodies that prevent adherence of Escherichia coli strains expressing colonization factor antigen I (CFA/I), CFA/II, and CFA/IV.

    PubMed

    Ruan, Xiaosai; Knudsen, David E; Wollenberg, Katie M; Sack, David A; Zhang, Weiping

    2014-02-01

    Diarrhea is the second leading cause of death in children younger than 5 years and continues to be a major threat to global health. Enterotoxigenic Escherichia coli (ETEC) strains are the most common bacteria causing diarrhea in developing countries. ETEC strains are able to attach to host small intestinal epithelial cells by using bacterial colonization factor antigen (CFA) adhesins. This attachment helps to initiate the diarrheal disease. Vaccines that induce antiadhesin immunity to block adherence of ETEC strains that express immunologically heterogeneous CFA adhesins are expected to protect against ETEC diarrhea. In this study, we created a CFA multiepitope fusion antigen (MEFA) carrying representative epitopes of CFA/I, CFA/II (CS1, CS2, and CS3), and CFA/IV (CS4, CS5, and CS6), examined its immunogenicity in mice, and assessed the potential of this MEFA as an antiadhesin vaccine against ETEC. Mice intraperitoneally immunized with this CFA MEFA exhibited no adverse effects and developed immune responses to CFA/I, CFA/II, and CFA/IV adhesins. Moreover, after incubation with serum of the immunized mice, ETEC or E. coli strains expressing CFA/I, CFA/II, or CFA/IV adhesins were significantly inhibited in adherence to Caco-2 cells. Our results indicated this CFA MEFA elicited antibodies that not only cross-reacted to CFA/I, CFA/II and CFA/IV adhesins but also broadly inhibited adherence of E. coli strains expressing these seven adhesins and suggested that this CFA MEFA could be a candidate to induce broad-spectrum antiadhesin protection against ETEC diarrhea. Additionally, this antigen construction approach (creating an MEFA) may be generally used in vaccine development against heterogenic pathogens. PMID:24351757

  5. HIV Medication Adherence

    MedlinePlus

    HIV Treatment HIV Medication Adherence (Last updated 3/1/2016; last reviewed 3/1/2016) Key Points Medication adherence means sticking ... exactly as prescribed. Why is adherence to an HIV regimen important? Adherence to an HIV regimen gives ...

  6. Efficiency of vanilla, patchouli and ylang ylang essential oils stabilized by iron oxide@C14 nanostructures against bacterial adherence and biofilms formed by Staphylococcus aureus and Klebsiella pneumoniae clinical strains.

    PubMed

    Bilcu, Maxim; Grumezescu, Alexandru Mihai; Oprea, Alexandra Elena; Popescu, Roxana Cristina; Mogoșanu, George Dan; Hristu, Radu; Stanciu, George A; Mihailescu, Dan Florin; Lazar, Veronica; Bezirtzoglou, Eugenia; Chifiriuc, Mariana Carmen

    2014-01-01

    Biofilms formed by bacterial cells are associated with drastically enhanced resistance against most antimicrobial agents, contributing to the persistence and chronicization of the microbial infections and to therapy failure. The purpose of this study was to combine the unique properties of magnetic nanoparticles with the antimicrobial activity of three essential oils to obtain novel nanobiosystems that could be used as coatings for catheter pieces with an improved resistance to Staphylococcus aureus and Klebsiella pneumoniae clinical strains adherence and biofilm development. The essential oils of ylang ylang, patchouli and vanilla were stabilized by the interaction with iron oxide@C14 nanoparticles to be further used as coating agents for medical surfaces. Iron oxide@C14 was prepared by co-precipitation of Fe+2 and Fe+3 and myristic acid (C14) in basic medium. Vanilla essential oil loaded nanoparticles pelliculised on the catheter samples surface strongly inhibited both the initial adherence of S. aureus cells (quantified at 24 h) and the development of the mature biofilm quantified at 48 h. Patchouli and ylang-ylang essential oils inhibited mostly the initial adherence phase of S. aureus biofilm development. In the case of K. pneumoniae, all tested nanosystems exhibited similar efficiency, being active mostly against the adherence K. pneumoniae cells to the tested catheter specimens. The new nanobiosystems based on vanilla, patchouli and ylang-ylang essential oils could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with anti-adherence and anti-biofilm properties.

  7. Efficiency of vanilla, patchouli and ylang ylang essential oils stabilized by iron oxide@C14 nanostructures against bacterial adherence and biofilms formed by Staphylococcus aureus and Klebsiella pneumoniae clinical strains.

    PubMed

    Bilcu, Maxim; Grumezescu, Alexandru Mihai; Oprea, Alexandra Elena; Popescu, Roxana Cristina; Mogoșanu, George Dan; Hristu, Radu; Stanciu, George A; Mihailescu, Dan Florin; Lazar, Veronica; Bezirtzoglou, Eugenia; Chifiriuc, Mariana Carmen

    2014-01-01

    Biofilms formed by bacterial cells are associated with drastically enhanced resistance against most antimicrobial agents, contributing to the persistence and chronicization of the microbial infections and to therapy failure. The purpose of this study was to combine the unique properties of magnetic nanoparticles with the antimicrobial activity of three essential oils to obtain novel nanobiosystems that could be used as coatings for catheter pieces with an improved resistance to Staphylococcus aureus and Klebsiella pneumoniae clinical strains adherence and biofilm development. The essential oils of ylang ylang, patchouli and vanilla were stabilized by the interaction with iron oxide@C14 nanoparticles to be further used as coating agents for medical surfaces. Iron oxide@C14 was prepared by co-precipitation of Fe+2 and Fe+3 and myristic acid (C14) in basic medium. Vanilla essential oil loaded nanoparticles pelliculised on the catheter samples surface strongly inhibited both the initial adherence of S. aureus cells (quantified at 24 h) and the development of the mature biofilm quantified at 48 h. Patchouli and ylang-ylang essential oils inhibited mostly the initial adherence phase of S. aureus biofilm development. In the case of K. pneumoniae, all tested nanosystems exhibited similar efficiency, being active mostly against the adherence K. pneumoniae cells to the tested catheter specimens. The new nanobiosystems based on vanilla, patchouli and ylang-ylang essential oils could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with anti-adherence and anti-biofilm properties. PMID:25375335

  8. Development of a FBG vortex flow sensor for high-temperature applications

    NASA Astrophysics Data System (ADS)

    Cheng, L. K.; Schiferli, W.; Nieuwland, R. A.; Franzen, A.; den Boer, J. J.; Jansen, T. H.

    2011-05-01

    A robust fibre optic flow sensor has been developed to measure liquid or gas flows at ambient temperatures up to 300 ºC and pressures up to 100 bar. While such environmental conditions are typical in pressurized steam systems in the oil and gas industry (downhole and surface), wider applications are envisaged. The flow sensor uses a specially-designed bluff body to generate vortex-induced pressure fluctuations as a function of flow. The pressure fluctuations result in mechanical strain fluctuations in the sensor plate which is attached to the bluff-body. This is detected by means of a Fibre Bragg Grating (FBG). The frequency of the pressure fluctuations is proportional to the flow velocity and is measured by analyzing the spectrum of the FBG sensor signal. Flow velocity measurements ranging from ~1 m/s to ~25 m/s have been demonstrated. Special mechanical design, gluing and packaging processes have been developed to enable applications at high temperatures and high pressures (HPHT). Although the working principle is the same as for conventional vortex flow meters, this flow sensor does not require electronics, which is a great advantage at high temperatures.

  9. Comparative Analysis of Super-Shedder Strains of Escherichia coli O157:H7 Reveals Distinctive Genomic Features and a Strongly Aggregative Adherent Phenotype on Bovine Rectoanal Junction Squamous Epithelial Cells

    PubMed Central

    Cote, Rebecca; Katani, Robab; Moreau, Matthew R.; Kudva, Indira T.; Arthur, Terrance M.; DebRoy, Chitrita; Mwangi, Michael M.; Albert, Istvan; Raygoza Garay, Juan Antonio; Li, Lingling; Brandl, Maria T.; Carter, Michelle Q.; Kapur, Vivek

    2015-01-01

    Shiga toxin-producing Escherichia coli O157:H7 (O157) are significant foodborne pathogens and pose a serious threat to public health worldwide. The major reservoirs of O157 are asymptomatic cattle which harbor the organism in the terminal recto-anal junction (RAJ). Some colonized animals, referred to as “super-shedders” (SS), are known to shed O157 in exceptionally large numbers (>104 CFU/g of feces). Recent studies suggest that SS cattle play a major role in the prevalence and transmission of O157, but little is known about the molecular mechanisms associated with super-shedding. Whole genome sequence analysis of an SS O157 strain (SS17) revealed a genome of 5,523,849 bp chromosome with 5,430 open reading frames and two plasmids, pO157 and pSS17, of 94,645 bp and 37,446 bp, respectively. Comparative analyses showed that SS17 is clustered with spinach-associated O157 outbreak strains, and belongs to the lineage I/II, clade 8, D group, and genotype 1, a subgroup of O157 with predicted hyper-virulence. A large number of non-synonymous SNPs and other polymorphisms were identified in SS17 as compared with other O157 strains (EC4115, EDL933, Sakai, TW14359), including in key adherence- and virulence-related loci. Phenotypic analyses revealed a distinctive and strongly adherent aggregative phenotype of SS17 on bovine RAJ stratified squamous epithelial (RSE) cells that was conserved amongst other SS isolates. Molecular genetic and functional analyses of defined mutants of SS17 suggested that the strongly adherent aggregative phenotype amongst SS isolates is LEE-independent, and likely results from a novel mechanism. Taken together, our study provides a rational framework for investigating the molecular mechanisms associated with SS, and strong evidence that SS O157 isolates have distinctive features and use a LEE-independent mechanism for hyper-adherence to bovine rectal epithelial cells. PMID:25664460

  10. Analysis of the performance of temperature compensation for fiber Bragg grating strain sensor

    NASA Astrophysics Data System (ADS)

    Meng, Fanyong; Jia, Limin

    2015-07-01

    FBG(fiber Bragg grating) strain sensor are widely applied in structure health monitoring, the temperature compensation problem is a key issue that impact the performance of the strain sensor, many kinds of temperature compensation method also have been put forward, but the compensation result get from these method can't meet the engineering requirements very well, especially when the ambient temperature changes rapidly due to the sunshine, the wind, the rain or other factors, and these impact can't avoid when monitoring an open-air structure project. Through engineering case and experiments test found that, the inaccurate compensation temperature is the key reason lead to test result error, and closer analysis could found that the temperature from strain sensitive FBG and temperature sensitive FBG have non synchronous phenomenon, and the error could be reach 1 degrees Celsius, so use the temperature from the same moment to compensate the strain calculation also can't get accurate results. The author thinks that the temperature non synchronous phenomenon may be caused by the temperature sensitive FBG and strain sensitive FBG have different package structure or package material, also may be installed on different positions, because all of these factors may lead to inconsistent temperature response speed between the two FBG when the ambient temperature changed rapidly. In order to confirm this conclusion, designed a FBG strain sensor package structure, the temperature sensitive FBG and strain sensitive FBG are packaged in one and the same structure with special stress isolation mechanism. Through temperature chamber test and engineering simulation experiment verified that the compensation temperature error could be reduced to 0.1 degrees Celsius, this will greatly improve the accuracy of temperature compensation for the FBG strain sensor.

  11. In-situ monitoring of curing and ageing effects in FRP plates using embedded FBG sensors

    NASA Astrophysics Data System (ADS)

    Xian, Guijun; Wang, Chuan; Li, Hui

    2010-04-01

    In recent years, fiber reinforced polymer (FRP) composites have been widely applied in civil engineering for retrofitting or renewal of existing structures. Since FRP composite may degrade when exposed to severe outdoor environments, a serious concern has been raised on its long term durability. In the present study, fiber Bragg grating (FBG) sensors were embedded in glass-, carbon- and basalt-fiber reinforced epoxy based FRP plates with wet lay-up technology, to in-situ monitor the stain changes in FRPs during the curing, and water immersion and freeze-thaw ageing processes. The study demonstrates that the curing of epoxy resin brings in a slight tension strain (e.g., 10 ~ 30 μɛ) along the fiber direction and a high contraction (e.g., ~ 1100μɛ) in the direction perpendicular to the fibers, mainly due to the resin shrinkage. The cured FRP strips were then subjected to distilled water immersion at 80oC and freeze-thaw cycles from -30°C to 30°C. Remarkable strain changes of FRPs due to the variation of the temperatures during freeze-thaw cycles indicate the potential property degradation from fatigue. The maximum strain change is dependent on the fiber types and directions to the fiber. Based on the monitored strain values with temperature change and water uptake content, CTE (coefficient of thermal expansion) and CME (coefficient of moisture expansion) are exactly determined for the FRPs.

  12. FBG Interrogation Method with High Resolution and Response Speed Based on a Reflective-Matched FBG Scheme.

    PubMed

    Cui, Jiwen; Hu, Yang; Feng, Kunpeng; Li, Junying; Tan, Jiubin

    2015-07-08

    In this paper, a high resolution and response speed interrogation method based on a reflective-matched Fiber Bragg Grating (FBG) scheme is investigated in detail. The nonlinear problem of the reflective-matched FBG sensing interrogation scheme is solved by establishing and optimizing the mathematical model. A mechanical adjustment to optimize the interrogation method by tuning the central wavelength of the reference FBG to improve the stability and anti-temperature perturbation performance is investigated. To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out. The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%. Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively.

  13. FBG Interrogation Method with High Resolution and Response Speed Based on a Reflective-Matched FBG Scheme

    PubMed Central

    Cui, Jiwen; Hu, Yang; Feng, Kunpeng; Li, Junying; Tan, Jiubin

    2015-01-01

    In this paper, a high resolution and response speed interrogation method based on a reflective-matched Fiber Bragg Grating (FBG) scheme is investigated in detail. The nonlinear problem of the reflective-matched FBG sensing interrogation scheme is solved by establishing and optimizing the mathematical model. A mechanical adjustment to optimize the interrogation method by tuning the central wavelength of the reference FBG to improve the stability and anti-temperature perturbation performance is investigated. To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out. The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%. Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively. PMID:26184195

  14. Eikenella corrodens adherence to human buccal epithelial cells.

    PubMed Central

    Yamazaki, Y; Ebisu, S; Okada, H

    1981-01-01

    The mechanism of Eikenella corrodens adherence to human buccal epithelial cells in vitro was studied. Initial experiments to determine the optimal conditions for adherence of E. corrodens to buccal epithelial cells showed that adherence was dependent on time, temperature, bacterial concentration, and pH. Different strains of E. corrodens varied in their ability to adhere, and strain 1073 showed the greatest ability in adherence. Strain 1073 was selected for studies of adherence mechanisms. Trypsin treatment or heating (100 degrees C, 10 min) of the bacterial cells abolished their capacity to adhere to buccal epithelial cells. Treatment of buccal epithelial cells with trypsin also abolished adherence of E. corrodens 1073, whereas neuraminidase treatment of buccal epithelial cells enhanced the adherence. The adherence was inhibited by ethylenediaminetetraacetic acid and restored by adding Ca2+. The adherence was remarkably inhibited by sugars containing D-galactose and n-acetyl-D-galactosamine. Treatment of neuraminidase-treated epithelial cells with sodium metaperiodate or alpha- and beta-galactosidase did not decrease the adherence. These data suggest that adherence of E. corrodens 1073 to human buccal epithelial cells may require the interaction of lectin-like proteins on the bacterial surface with galactose-like receptors on the surface of epithelial cells. PMID:6260661

  15. Treatment adherence in psychoses.

    PubMed

    David, Anthony S

    2010-12-01

    A well-conducted randomised controlled trial of an intervention to improve treatment adherence in psychosis published in this issue shows beneficial effects on self- and observer-rated adherence and trends towards fewer hospital readmissions. Partial adherence is the single most important barrier to optimal treatment. National Institute for Health and Clinical Excellence guidelines on adherence need to be revised.

  16. Design and realization of high precision FBG rain gauge based on triangle cantilever beam and its performance research

    NASA Astrophysics Data System (ADS)

    Lan, Ruo-ming; Cao, Yu-qiang

    2015-05-01

    A novel fiber Bragg grating (FBG) rain gauge is proposed in this paper to achieve high precision rainfall measurement. One core sensitive FBG, a temperature compensation FBG and a mechanical transition system construct this novel FBG rain gauge. Sensing principle of this FBG rain gauge is explained in detail, and its theoretical calculation model is also established, which shows that the relationship between center wavelength of sensitive FBG and external rainfall has very good linearity. To verify its detection performance, the calibration experiment on one prototype of this FBG rain gauge is carried out. After experiment data analysis, the detection precision of this FBG rain gauge is 15.4 μm which is almost two orders of magnitude higher than that of the existing rainfall measurement device. The experimental data confirm that this FBG rain gauge can achieve rainfall measurement with high precision.

  17. Persistent and transient Listeria monocytogenes strains from retail deli environments vary in their ability to adhere and form biofilms and rarely have inlA premature stop codons.

    PubMed

    Wang, Jingjin; Ray, Andrea J; Hammons, Susan R; Oliver, Haley F

    2015-02-01

    Based on recent risk assessments, up to 83% of listeriosis cases from deli meat in the United States are predicted to be from ready-to-eat deli meats contaminated during processing at retail grocery stores. Listeria monocytogenes is known to use sanitizer tolerance and biofilm formation to survive, but interplay of these mechanisms along with virulence potential and persistence mechanisms specific to deli environments had yet to be elucidated. In this study, 442 isolates from food and nonfood contact surfaces in 30 retail delis over 9 months were tested for inlA premature stop codons (PMSCs); inlA encodes InlA, which is necessary to cause listeriosis. A total of 96 isolates, composed of 23 persistent and 73 transient strains, were tested for adhesion and biofilm-forming ability and sanitizer tolerance. Only 10/442 isolates had inlA PMSCs (p<0.001). Strains with PMSCs were not persistent, even in delis with other persistent strains. Most (7/10) PMSC-containing isolates were collected from food contact surfaces (p<0.001); 6/10 PMSC-containing isolates were found in moderate prevalence delis (p<0.05). Persistent strains had enhanced adhesion on day 1 of a 5-day adhesion-biofilm formation assay. However, there was no significant difference in sanitizer tolerance between persistent and transient strains. Results suggest that foods contaminated with persistent L. monocytogenes strains from the retail environment are (1) likely to have wild-type virulence potential and (2) may persist due to increased adhesion and biofilm formation capacity rather than sanitizer tolerance, thus posing a significant public health risk. PMID:25569840

  18. Adherence of Mycoplasma hyopneumoniae to cell monolayers.

    PubMed

    Zielinski, G C; Young, T; Ross, R F; Rosenbusch, R F

    1990-03-01

    This work was an attempt to develop an in vitro adherence model for Mycoplasma hyopneumoniae, using monolayers of human and porcine lung fibroblasts and porcine kidney cells. Mycoplasma hyopneumoniae grown in Friis mycoplasma broth was radiolabeled with 35[S]-methionine, washed, concentrated, and inoculated on the monolayers. After 15 minutes of centrifugation to facilitate adherence, monolayers were washed 3 times, dissolved with 0.1N NaOH, and suspended in scintillation liquid, and the radioactivity was determined in a liquid scintillation counter. Adherence, measured as a percentage of counts added, varied according to the mycoplasma strain and the cell line used. Comparison of strains J, 144L, and 232 of M hyopneumoniae revealed 7.5 +/- 5.9, 31.9 +/- 13, and 9.6 +/- 5% adherence to porcine kidney cells, respectively. Slightly different, but proportionally the same relationships were obtained with swine or human fibroblasts. Adherence was decreased slightly by repeated washings of the mycoplasma-treated cell monolayers; however, a plateau was reached, indicating irreversibility of the adherence process. Pretreatment of cell monolayers with nonlabeled organisms substantially blocked adherence by labeled organisms. Dilution of labeled organisms resulted in an increased proportion adhering. Therefore, it appears that the adherence was a receptor-dependent event. Treatment of the mycoplasmas with trypsin prior to the inoculation of monolayers resulted in a marked reduction in adherence. Treatment of the mycoplasmas with hyperimmune swine serum against M hyopneumoniae or normal swine serum resulted in 80 to 90% reduction of adherence; however, no inhibition occurred when mycoplasmas were treated with purified IgG from the hyperimmune serum.

  19. Orthodontic mechanics using mini-implant measured by FBG

    NASA Astrophysics Data System (ADS)

    Trannin, Pamela G.; Milczewski, Maura S.; de Oliveira, Walmir; Guariza Filho, Odilon; Lopes, Stephani C. P. S.; Kalinowski, Hypolito J.

    2015-07-01

    The magnitude of the force generated during orthodontic mechanics anchored in mini-implant in a maxilla model was analyzed. Data was collected during the insertion of the mini-implant and at the moment of applying forces to the structure of the maxilla and dentition. To obtain quantitative results, the Fibre Bragg Gratings (FBG) were inserted in an elastomeric material reproducing a maxilla model. It was observed levels of forces of approximately 3,78N next to the root of first premolar by the insertion of the mini-implant and different levels of the force to different orthodontic mechanics applied on the dental system.

  20. Oscillatory behaviour in Type IA FBG: ruling out chemical complexity

    NASA Astrophysics Data System (ADS)

    Simpson, George; Kalli, Kyriacos; Canning, John; Lacraz, Amedee

    2015-09-01

    Type IA FBG are regenerated gratings that appear in hydrogenated germanosilicate fibre of all types during prolonged UV exposure. The gratings are characterised by a large Bragg wavelength shift and a concomitant increase in the mean fibre core index. Modulated index changes are complex by comparison and significantly weaker, often characterised by oscillatory growth behaviour. Low thermal stability of Type IA gratings suggests a possible chemical role similar to thermally processed optical fibres where autocatalysis has been observed. We show that GeOH and SiOH formation are not out-of-phase and follow each other, with no evidence of autocatalysis, ruling out a chemical origin.

  1. Biofilm-forming ability and adherence to poly-(methyl-methacrylate) acrylic resin materials of oral Candida albicans strains isolated from HIV positive subjects

    PubMed Central

    Uzunoglu, Emel; Dolapci, Istar; Dogan, Arife

    2014-01-01

    PURPOSE This study evaluated the adhesion to acrylic resin specimens and biofilm formation capability of Candida albicans strains isolated from HIV positive subjects' oral rinse solutions. MATERIALS AND METHODS The material tested was a heat-cured acrylic resin (Acron Duo). Using the adhesion and crystal violet assays, 14 oral Candida albicans isolated from HIV-positive subjects and 2 references Candida strains (C. albicans ATCC 90028 and C. albicans ATCC 90128) were compared for their biofilm production and adhesion properties to acrylic surfaces in vitro. RESULTS There were no significant differences in adhesion (P=.52) and biofilm formation assays (P=.42) by statistical analysis with Mann-Whitney test. CONCLUSION Denture stomatitis and increased prevalence of candidal carriage in HIV infected patients is unlikely to be related to the biofilm formation and adhesion abilities of C. albicans to acrylic resin materials. PMID:24605203

  2. [The Research on Optic Fiber FBG Corrosion Sensor Based on the Analysis of the Spectral Characteristics].

    PubMed

    Zhang, Jun; Zeng, Jie; Wang, Bo; Wang, Wen-juan; Liang, Da-kai; Liu, Xiao-ying

    2016-03-01

    Aiming at meeting the need of aluminum corrosion monitoring in aerospace field, a pre-load type fiber grating corrosion sensor based on an aluminum thin tube structure is proposed. The corrosion sensor of aluminum alloy structure in-service monitoring mechanism is studied, a theoretical model about the relation of FBG reflection spectral characteristics and aluminum thickness variation is also obtained. Optical fiber grating corrosion monitoring test system based on the capillary structure of aluminum alloy is constructed by acid-base environment. The problem of cross sensitivity of temperature and strain is solved by configuring an optical fiber grating which is not affected by strain and only sensitive to temperature inside the aluminum alloy tube. The results shows that he aluminum tube packaging design not only can sense the effects of corrosion on the mechanical properties, but also can interference shielding effect of corrosion on the tube optical fiber sensing device. With the deepening of the metal tube corrosion and aluminum alloy tube thickness gradually thinning, fiber grating reflective spectrum gradually shift to the short wavelength and the wall thickness and the grating center wavelength offset has a good monotonic relation. These characteristics can provide useful help to further research corrosion online monitoring based on optic fiber sensor. PMID:27400537

  3. Adherence of Clostridium thermocellum to cellulose.

    PubMed Central

    Bayer, E A; Kenig, R; Lamed, R

    1983-01-01

    The adherence of Clostridium thermocellum, a cellulolytic, thermophilic anaerobe, to its insoluble substrate (cellulose) was studied. The adherence phenomenon was determined to be selective for cellulose. The observed adherence was not significantly affected by various parameters, including salts, pH, temperature, detergents, or soluble sugars. A spontaneous adherence-defective mutant strain (AD2) was isolated from the wild-type strain YS. Antibodies were prepared against the bacterial cell surface and rendered specific to the cellulose-binding factor (CBF) by adsorption to mutant AD2 cells. By using these CBF-specific antibodies, crossed immunoelectrophoresis of cell extracts revealed a single discrete precipitation peak in the parent strain which was absent in the mutant. This difference was accompanied by an alteration in the polypeptide profile whereby sonicates of strain YS contained a 210,000-molecular-weight band which was missing in strain AD2. The CBF antigen could be removed from cell extracts by adsorption to cellulose. A combined gel-overlay--immunoelectrophoretic technique demonstrated that the cellulose-binding properties of the CBF were accompanied by carboxymethylcellulase activity. During the exponential phase of growth, a large part of the CBF antigen and related carboxymethylcellulase activity was associated with the cells of wild-type strain YS. However, the amounts decreased in stationary-phase cells. Cellobiose-grown mutant AD2 cells lacked the cell-associated CBF, but the latter was detected in the extracellular fluid. Increased levels of CBF were observed when cells were grown on cellulose. In addition, mutant AD2 regained cell-associated CBF together with the property of cellulose adherence. The presence of the CBF antigen and related adherence characteristics appeared to be a phenomenon common to other naturally occurring strains of this species. Images PMID:6630152

  4. Micro-structured femtosecond laser assisted FBG hydrogen sensor.

    PubMed

    Karanja, Joseph Muna; Dai, Yutang; Zhou, Xian; Liu, Bin; Yang, Minghong

    2015-11-30

    We discuss hydrogen sensors based on fiber Bragg gratings (FBGs) micro-machined by femtosecond laser to form microgrooves and sputtered with Pd/Ag composite film. The atomic ratio of the two metals is controlled at Pd:Ag = 3:1. At room temperature, the hydrogen sensitivity of the sensor probe micro-machined by 75 mW laser power and sputtered with 520 nm of Pd/Ag film is 16.5 pm/%H. Comparably, the standard FBG hydrogen sensitivity becomes 2.5 pm/%H towards the same 4% hydrogen concentration. At an ambient temperature of 35°C, the processed sensor head has a dramatic rise in hydrogen sensitivity. Besides, the sensor shows good response and repeatability during hydrogen concentration test. PMID:26698733

  5. A novel high-sensitivity FBG pressure sensor

    NASA Astrophysics Data System (ADS)

    Yao, Zhenhua; Fu, Tao; Leng, Jinsong

    2007-07-01

    A novel pressure sensor based on FBG is designed in this paper. Not only in normal environment, also does it accurately work in water and petrol where other conventional sensors can not work normally. In this paper, the principle of the novel sensor is introduced, and two experiments are further performed: One is keeping the sensor flatly in the gastight silo whose pressure is supplied by an air compressing engine, and the other one is keeping the sensor in liquid. The analysis of the result data demonstrates that the sensor possesses high sensitivity, high linearity, high precision and repeatability. Its experimental linearity and sensitivity approach 0.99858 and 5.35×10 -3MPa -1, respectively. It is also discussed using the sensor to measure the volume in tank.

  6. Novel tunable Fabry-Perot filters for FBG sensing system

    NASA Astrophysics Data System (ADS)

    Wu, Wei; Tong, Xinglin; Liu, Xin; Chen, Ting

    2008-12-01

    Tunable filters with a wide tunable rang have been found wide applications and be the key component in fiber optical communication system and fiber sensor system. It is hard to fabricate a fiber Fabry-Perot tunable filter. In this paper, the principles of Fabry-Perot filter is introduced, and a novel tunable Fabry-Perot filter is designed and fabricated. The fabricated process of the tunable filter is described and the transmission spectrum of tunable F-P filter in experiment is given and discussed. The tunable F-P filter has the advantages of simple structure, low modulated voltage and cost effectiveness. The filter can be applied to wavelength interrogation in fiber Bragg grating (FBG) sensing system to detect the drift of the fiber Bragg wavelength.

  7. Fiber laser strain sensor based in the measurement of a Sagnac interferometer optical power spectrum

    NASA Astrophysics Data System (ADS)

    Durán Sánchez, M.; Álvarez Tamayo, R. I.; Pottiez, O.; Kuzin, E. A.; Ibarra-Escamilla, B.; Barcelata Pinzón, A.

    2014-06-01

    In this paper a linear cavity Erbium doped fiber (EDF) laser based in a fiber Bragg grating (FBG) and a fiber optical loop mirror with a high birefringence fiber in the loop (Hi-Bi FOLM) is used as a strain sensor. The Fabry-Perot cavity is formed by the FBG and the Hi-Bi FOLM, used as a measurement system of strain variations produced on the FBG, used as a strain sensor device. Usually, fiber laser sensor experimental setups determine the measured variable magnitude by using of an optical spectrum analyzer (OSA). Hi-Bi FOLM transmission spectrum wavelength displacement by fiber loop temperature variations measurement can be an attractive application exploiting the characteristics of FOLM transmission spectrum behavior due to Hi-Bi fiber loop temperature variations to determine the FBG strain applied through the maximal optical power monitoring by simple use of a photodetector and a temperature meter.

  8. Genetic algorithm-support vector regression for high reliability SHM system based on FBG sensor network

    NASA Astrophysics Data System (ADS)

    Zhang, XiaoLi; Liang, DaKai; Zeng, Jie; Asundi, Anand

    2012-02-01

    Structural Health Monitoring (SHM) based on fiber Bragg grating (FBG) sensor network has attracted considerable attention in recent years. However, FBG sensor network is embedded or glued in the structure simply with series or parallel. In this case, if optic fiber sensors or fiber nodes fail, the fiber sensors cannot be sensed behind the failure point. Therefore, for improving the survivability of the FBG-based sensor system in the SHM, it is necessary to build high reliability FBG sensor network for the SHM engineering application. In this study, a model reconstruction soft computing recognition algorithm based on genetic algorithm-support vector regression (GA-SVR) is proposed to achieve the reliability of the FBG-based sensor system. Furthermore, an 8-point FBG sensor system is experimented in an aircraft wing box. The external loading damage position prediction is an important subject for SHM system; as an example, different failure modes are selected to demonstrate the SHM system's survivability of the FBG-based sensor network. Simultaneously, the results are compared with the non-reconstruct model based on GA-SVR in each failure mode. Results show that the proposed model reconstruction algorithm based on GA-SVR can still keep the predicting precision when partial sensors failure in the SHM system; thus a highly reliable sensor network for the SHM system is facilitated without introducing extra component and noise.

  9. Dynamic optical arbitrary waveform generation with amplitude controlled by interference of two FBG arrays.

    PubMed

    Zhang, Ailing; Li, Changxiu

    2012-10-01

    In this paper, a novel structure of dynamic optical arbitrary waveform generation (O-AWG) with amplitude controlled by interference of two fiber Bragg grating (FBG) arrays is proposed. The FBG array consists of several FBGs and fiber stretchers (FSs). The amplitude is controlled by FSs through interference of two FBG arrays. The phase is controlled by FSs simultaneously. As a result, optical pulse trains with various waveforms as well as pulse trains with nonuniform pulse intensity, pulse spacing and pulse width in each period are obtained via FSs adjustment to change the phase shift of signal in each array. PMID:23188271

  10. Biofilm formation and fibrinogen and fibronectin binding activities by Corynebacterium pseudodiphtheriticum invasive strains.

    PubMed

    Souza, Monica Cristina; dos Santos, Louisy Sanches; Sousa, Leonardo Paiva; Faria, Yuri Vieira; Ramos, Juliana Nunes; Sabbadini, Priscila Soares; da Santos, Cíntia Silva; Nagao, Prescilla Emy; Vieira, Verônica Viana; Gomes, Débora Leandro Rama; Hirata Júnior, Raphael; Mattos-Guaraldi, Ana Luiza

    2015-06-01

    Biofilm-related infections are considered a major cause of morbidity and mortality in hospital environments. Biofilms allow microorganisms to exchange genetic material and to become persistent colonizers and/or multiresistant to antibiotics. Corynebacterium pseudodiphtheriticum (CPS), a commensal bacterium that colonizes skin and mucosal sites has become progressively multiresistant and responsible for severe nosocomial infections. However, virulence factors of this emergent pathogen remain unclear. Herein, we report the adhesive properties and biofilm formation on hydrophilic (glass) and hydrophobic (plastic) abiotic surfaces by CPS strains isolated from patients with localized (ATCC10700/Pharyngitis) and systemic (HHC1507/Bacteremia) infections. Adherence to polystyrene attributed to hydrophobic interactions between bacterial cells and this negatively charged surface indicated the involvement of cell surface hydrophobicity in the initial stage of biofilm formation. Attached microorganisms multiplied and formed microcolonies that accumulated as multilayered cell clusters, a step that involved intercellular adhesion and synthesis of extracellular matrix molecules. Further growth led to the formation of dense bacterial aggregates embedded in the exopolymeric matrix surrounded by voids, typical of mature biofilms. Data also showed CPS recognizing human fibrinogen (Fbg) and fibronectin (Fn) and involvement of these sera components in formation of "conditioning films". These findings suggested that biofilm formation may be associated with the expression of different adhesins. CPS may form biofilms in vivo possibly by an adherent biofilm mode of growth in vitro currently demonstrated on hydrophilic and hydrophobic abiotic surfaces. The affinity to Fbg and Fn and the biofilm-forming ability may contribute to the establishment and dissemination of infection caused by CPS.

  11. Effects of a pharmaceutical care model on medication adherence and glycemic control of people with type 2 diabetes

    PubMed Central

    Chung, Wen Wei; Chua, Siew Siang; Lai, Pauline Siew Mei; Chan, Siew Pheng

    2014-01-01

    Background Diabetes mellitus is a lifelong chronic condition that requires self-management. Lifestyle modification and adherence to antidiabetes medications are the major determinants of therapeutic success in the management of diabetes. Purpose To assess the effects of a pharmaceutical care (PC) model on medication adherence and glycemic levels of people with type 2 diabetes mellitus. Patients and methods A total of 241 people with type 2 diabetes were recruited from a major teaching hospital in Malaysia and allocated at random to the control (n=121) or intervention (n=120) groups. Participants in the intervention group received PC from an experienced pharmacist, whereas those in the control group were provided the standard pharmacy service. Medication adherence was assessed using the Malaysian Medication Adherence Scale, and glycemic levels (glycated hemoglobin values and fasting blood glucose [FBG]) of participants were obtained at baseline and after 4, 8, and 12 months. Results At baseline, there were no significant differences in demographic data, medication adherence, and glycemic levels between participants in the control and intervention groups. However, statistically significant differences in FBG and glycated hemoglobin values were observed between the control and intervention groups at months 4, 8, and 12 after the provision of PC (median FBG, 9.0 versus 7.2 mmol/L [P<0.001]; median glycated hemoglobin level, 9.1% versus 8.0% [P<0.001] at 12 months). Medication adherence was also significantly associated with the provision of PC, with a higher proportion in the intervention group than in the control group achieving it (75.0% versus 58.7%; P=0.007). Conclusion The provision of PC has positive effects on medication adherence as well as the glycemic control of people with type 2 diabetes. Therefore, the PC model used in this study should be duplicated in other health care settings for the benefit of more patients with type 2 diabetes. PMID:25214772

  12. A sliding-mode-based observer to identify faults in FBG sensors embedded in composite structures

    NASA Astrophysics Data System (ADS)

    Cazzulani, Gabriele; Cinquemani, Simone; Ronchi, Marco

    2016-04-01

    Optical strain gauges, such as Fiber Bragg Gratings (FBG), have a great potential for smart structures, thanks to their small transversal size and the possibility to make an array of many sensors. They can be embedded in composite structures and their effect on the structure is nearly negligible. These advantages make them very interesting in the field of active vibration suppression. Unfortunately their low reliability is an obstacle to their use in such applications. For this reason, this paper introduces a fault identification algorithm to identify online those sensors which are not working correctly. The algorithm is based on the use of a sliding mode observer to estimate the coherence of measurements, and then to highlight possible faults. Once identified, the corresponding sensors can be excluded from the feedback loop of the control algorithm to avoid unwanted behaviors or instabilities. Numerical and experimental tests have been carried out on a carbon fiber structure considering different fault conditions. Results show it is possible to identify the faulty sensors and thus improve the signals used in the feedback loop.

  13. Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials.

    PubMed

    Rodriguez, George; Jaime, Marcelo; Balakirev, Fedor; Mielke, Chuck H; Azad, Abul; Marshall, Bruce; La Lone, Brandon M; Henson, Bryan; Smilowitz, Laura

    2015-06-01

    A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersive line. Signals are recorded using a single 35 GHz photodetector and a 50 G Samples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO3. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ΔL/L<10-4) in the material. A second application used FBG sensing of pressure dynamics to nearly 2 GPa in the thermal ignition of the high explosive PBX-9501 is also demonstrated. Both applications demonstrate the use of this FBG interrogation system in dynamical extreme conditions that would otherwise not be possible using traditional FBG interrogation approaches that are deemed too slow to resolve such events.

  14. Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials.

    PubMed

    Rodriguez, George; Jaime, Marcelo; Balakirev, Fedor; Mielke, Chuck H; Azad, Abul; Marshall, Bruce; La Lone, Brandon M; Henson, Bryan; Smilowitz, Laura

    2015-06-01

    A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersive line. Signals are recorded using a single 35 GHz photodetector and a 50 G Samples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO3. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ΔL/L<10-4) in the material. A second application used FBG sensing of pressure dynamics to nearly 2 GPa in the thermal ignition of the high explosive PBX-9501 is also demonstrated. Both applications demonstrate the use of this FBG interrogation system in dynamical extreme conditions that would otherwise not be possible using traditional FBG interrogation approaches that are deemed too slow to resolve such events. PMID:26072789

  15. Bacterial adherence to anodized titanium alloy

    NASA Astrophysics Data System (ADS)

    Pérez-Jorge Peremarch, C.; Pérez Tanoira, R.; Arenas, M. A.; Matykina, E.; Conde, A.; De Damborenea, J. J.; Gómez Barrena, E.; Esteban, J.

    2010-11-01

    The aim of this study was to evaluate Staphylococcus sp adhesion to modified surfaces of anodized titanium alloy (Ti-6Al-4V). Surface modification involved generation of fluoride-containing titanium oxide nanotube films. Specimens of Ti-6Al-4V alloy 6-4 ELI-grade 23- meets the requirements of ASTM F136 2002A (AMS 2631B class A1) were anodized in a mixture of sulphuric/hydrofluoric acid at 20 V for 5 and 60 min to form a 100 nm-thick porous film of 20 nm pore diameter and 230 nm-thick nanotube films of 100 nm in diameter. The amount of fluorine in the oxide films was of 6% and of 4%, respectively. Collection strains and six clinical strains each of Staphylococcus aureus and Staphylococcus epidermidis were studied. The adherence study was performed using a previously published protocol by Kinnari et al. The experiments were performed in triplicates. As a result, lower adherence was detected for collection strains in modified materials than in unmodified controls. Differences between clinical strains were detected for both species (p<0.0001, Kruskal-Wallis test), although global data showed similar results to that of collection strains (p<0.0001, Kruskal-Wallis test). Adherence of bacteria to modified surfaces was decreased for both species. The results also reflect a difference in the adherence between S. aureus and S. epidermidis to the modified material. As a conclusion, not only we were able to confirm the decrease of adherence in the modified surface, but also the need to test multiple clinical strains to obtain more realistic microbiological results due to intraspecies differences.

  16. Fiber Bragg Grating (FBG) sensors as flatness and mechanical stretching sensors

    NASA Astrophysics Data System (ADS)

    Abbaneo, D.; Abbas, M.; Abbrescia, M.; Abdelalim, A. A.; Abi Akl, M.; Aboamer, O.; Acosta, D.; Ahmad, A.; Ahmed, W.; Ahmed, W.; Aleksandrov, A.; Aly, R.; Altieri, P.; Asawatangtrakuldee, C.; Aspell, P.; Assran, Y.; Awan, I.; Bally, S.; Ban, Y.; Banerjee, S.; Barashko, V.; Barria, P.; Bencze, G.; Beni, N.; Benussi, L.; Bhopatkar, V.; Bianco, S.; Bos, J.; Bouhali, O.; Braghieri, A.; Braibant, S.; Buontempo, S.; Calabria, C.; Caponero, M.; Caputo, C.; Cassese, F.; Castaneda, A.; Cauwenbergh, S.; Cavallo, F. R.; Celik, A.; Choi, M.; Choi, S.; Christiansen, J.; Cimmino, A.; Colafranceschi, S.; Colaleo, A.; Conde Garcia, A.; Czellar, S.; Dabrowski, M. M.; De Lentdecker, G.; De Oliveira, R.; De Robertis, G.; Dildick, S.; Dorney, B.; Elmetenawee, W.; Endroczi, G.; Errico, F.; Fenyvesi, A.; Ferry, S.; Furic, I.; Giacomelli, P.; Gilmore, J.; Golovtsov, V.; Guiducci, L.; Guilloux, F.; Gutierrez, A.; Hadjiiska, R. M.; Hassan, A.; Hauser, J.; Hoepfner, K.; Hohlmann, M.; Hoorani, H.; Iaydjiev, P.; Jeng, Y. G.; Kamon, T.; Karchin, P.; Korytov, A.; Krutelyov, S.; Kumar, A.; Kim, H.; Lee, J.; Lenzi, T.; Litov, L.; Loddo, F.; Madorsky, A.; Maerschalk, T.; Maggi, M.; Magnani, A.; Mal, P. K.; Mandal, K.; Marchioro, A.; Marinov, A.; Masod, R.; Majumdar, N.; Merlin, J. A.; Mitselmakher, G.; Mohanty, A. K.; Mohamed, S.; Mohapatra, A.; Molnar, J.; Muhammad, S.; Mukhopadhyay, S.; Naimuddin, M.; Nuzzo, S.; Oliveri, E.; Pant, L. M.; Paolucci, P.; Park, I.; Passeggio, G.; Passamonti, L.; Pavlov, B.; Philipps, B.; Piccolo, D.; Pierluigi, D.; Postema, H.; Puig Baranac, A.; Radi, A.; Radogna, R.; Raffone, G.; Ranieri, A.; Rashevski, G.; Riccardi, C.; Rodozov, M.; Rodrigues, A.; Ropelewski, L.; RoyChowdhury, S.; Russo, A.; Ryu, G.; Ryu, M. S.; Safonov, A.; Salva, S.; Saviano, G.; Sharma, A.; Sharma, A.; Sharma, R.; Shah, A. H.; Shopova, M.; Sturdy, J.; Sultanov, G.; Swain, S. K.; Szillasi, Z.; Talvitie, J.; Tatarinov, A.; Tuuva, T.; Tytgat, M.; Vai, I.; Van Stenis, M.; Venditti, R.; Verhagen, E.; Verwilligen, P.; Vitulo, P.; Volkov, S.; Vorobyev, A.; Wang, D.; Wang, M.; Yang, U.; Yang, Y.; Yonamine, R.; Zaganidis, N.; Zenoni, F.; Zhang, A.

    2016-07-01

    A novel approach which uses Fiber Bragg Grating (FBG) sensors has been utilized to assess and monitor the flatness of Gaseous Electron Multipliers (GEM) foils. The setup layout and preliminary results are presented.

  17. V-groove-based compact FBG package for thermal tuning and mechanical stability

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Fang, Wei; Wang, Di; Chen, Di-Jun; Cai, Hai-Wen; Qu, Rong-Hui

    2016-04-01

    We demonstrated a V-groove-based fiber Bragg grating (FBG) package that has been glue-filled and cured to make it a bulky component with much improved mechanical stability. The V-groove can be executed with many types of materials including plastics, ceramics, semiconductors, and metals, providing an easy method for redesigning the thermal tuning performance of FBGs by selecting among a wide variety of materials and processes. We achieved more than 10-nm thermal wavelength tuning and thermal sensitivity ranging from 15 to 160 pm/K. The original FBG spectrum can be maintained without any degradation because the fiber is buried in the V-groove. The compact package does not increase the original grating length and turns the FBG into a planar waveguide grating, improving FBG applications in telecommunications, external cavity lasers, and sensing areas.

  18. Integrated FBG sensors interrogator in silicon photonic platform using active interferometer monitoring

    NASA Astrophysics Data System (ADS)

    Marin, Y. E.; Nannipieri, T.; Di Pasquale, F.; Oton, C. J.

    2016-05-01

    We experimentally demonstrate the feasibility of Fiber Bragg Grating sensors interrogation using integrated unbalanced Mach-Zehnder Interferometers (MZI) and phase sensitive detection in silicon-on-insulator (SOI) platform. The Phase- Generated Carrier (PGC) demodulation technique is used to detect phase changes, avoiding signal fading. Signal processing allows us to extract the wavelength shift from the signal patterns, allowing accurate dynamic FBG interrogation. High resolution and low cost chips with multiple interrogators and photodetectors on board can be realized by exploiting the advantages of large scale fabrication capabilities of well-established silicon based industrial infrastructures. Simultaneous dynamic reading of a large number of FBG sensors can lead to large volume market applications of the technology in several strategic industrial fields. The performance of the proposed integrated FBG interrogator is validated by comparing with a commercial FBG readout based on a spectrometer and used as a reference.

  19. Adherence of Bilophila wadsworthia to cultured human embryonic intestinal cells.

    PubMed

    Gerardo, S H; Garcia, M M; Wexler, H M; Finegold, S M

    1998-02-01

    Adherence of Bilophila wadsworthia to the cultured human embryonic intestinal cell line, Intestine 407 (Int 407), varied among the strains tested from strongly adherent (76-100% cells positive for one or more adherent bacteria) to non- or weakly adherent (0-25% positive cells). Although negative staining revealed that infrequent cells of an adherent strain, WAL 9077, the adherent type-strain, WAL 7959, and a non-adherent strain, WAL 8448, expressed loosely associated fimbrial structures, a role for these structures in adhesion could not be confirmed with either scanning or thin-section electron micrography. Ruthenium red staining of thin-section preparations and subsequent electron microscopy failed to reveal an extensive extracellular polysaccharide layer. SDS-PAGE analysis of crude outer membrane fractions of WAL 9077 and WAL 8448 demonstrated clear differences in their major and minor outer membrane protein components. Thus, we postulate that the adherence of B. wadsworthia to Int 407 cells is mediated by an outer membrane or cell wall component. PMID:16887620

  20. FBG1 Is the Final Arbitrator of A1AT-Z Degradation

    PubMed Central

    Wen, John H.; Wen, Hsiang; Gibson-Corley, Katherine N.; Glenn, Kevin A.

    2015-01-01

    Alpha-1 antitrypsin deficiency is the leading cause of childhood liver failure and one of the most common lethal genetic diseases. The disease-causing mutant A1AT-Z fails to fold correctly and accumulates in the endoplasmic reticulum (ER) of the liver, resulting in hepatic fibrosis and hepatocellular carcinoma in a subset of patients. Furthermore, A1AT-Z sequestration in hepatocytes leads to a reduction in A1AT secretion into the serum, causing panacinar emphysema in adults. The purpose of this work was to elucidate the details by which A1AT-Z is degraded in hepatic cell lines. We identified the ubiquitin ligase FBG1, which has been previously shown to degrade proteins by both the ubiquitin proteasome pathway and autophagy, as being key to A1AT-Z degradation. Using chemical and genetic approaches we show that FBG1 degrades A1AT-Z through both the ubiquitin proteasome system and autophagy. Overexpression of FBG1 decreases the half-life of A1AT-Z and knocking down FBG1 in a hepatic cell line, and in mice results in an increase in ATAT. Finally, we show that FBG1 degrades A1AT-Z through a Beclin1-dependent arm of autophagy. In our model, FBG1 acts as a safety ubiquitin ligase, whose function is to re-ubiquitinate ER proteins that have previously undergone de-ubiquitination to ensure they are degraded. PMID:26295339

  1. FBG1 Is the Final Arbitrator of A1AT-Z Degradation.

    PubMed

    Wen, John H; Wen, Hsiang; Gibson-Corley, Katherine N; Glenn, Kevin A

    2015-01-01

    Alpha-1 antitrypsin deficiency is the leading cause of childhood liver failure and one of the most common lethal genetic diseases. The disease-causing mutant A1AT-Z fails to fold correctly and accumulates in the endoplasmic reticulum (ER) of the liver, resulting in hepatic fibrosis and hepatocellular carcinoma in a subset of patients. Furthermore, A1AT-Z sequestration in hepatocytes leads to a reduction in A1AT secretion into the serum, causing panacinar emphysema in adults. The purpose of this work was to elucidate the details by which A1AT-Z is degraded in hepatic cell lines. We identified the ubiquitin ligase FBG1, which has been previously shown to degrade proteins by both the ubiquitin proteasome pathway and autophagy, as being key to A1AT-Z degradation. Using chemical and genetic approaches we show that FBG1 degrades A1AT-Z through both the ubiquitin proteasome system and autophagy. Overexpression of FBG1 decreases the half-life of A1AT-Z and knocking down FBG1 in a hepatic cell line, and in mice results in an increase in ATAT. Finally, we show that FBG1 degrades A1AT-Z through a Beclin1-dependent arm of autophagy. In our model, FBG1 acts as a safety ubiquitin ligase, whose function is to re-ubiquitinate ER proteins that have previously undergone de-ubiquitination to ensure they are degraded.

  2. Fusion of a FBG-based health monitoring system for wind turbines with a fiber-optic lightning detection system

    NASA Astrophysics Data System (ADS)

    Krämer, Sebastian G. M.; Wiesent, Benjamin; Müller, Mathias S.; Puente León, Fernando; Méndez Hernández, Yarú

    2008-04-01

    Wind turbine blades are made of composite materials and reach a length of more than 42 meters. Developments for modern offshore turbines are working on about 60 meters long blades. Hence, with the increasing height of the turbines and the remote locations of the structures, health monitoring systems are becoming more and more important. Therefore, fiber-optic sensor systems are well-suited, as they are lightweight, immune against electromagnetic interference (EMI), and as they can be multiplexed. Based on two separately existing concepts for strain measurements and lightning detection on wind turbines, a fused system is presented. The strain measurement system is based on a reflective fiber-Bragg-grating (FBG) network embedded in the composite structure of the blade. For lightning detection, transmissive &fiber-optic magnetic field sensors based on the Faraday effect are used to register the lightning parameters and estimate the impact point. Hence, an existing lightning detection system will be augmented, due to the fusion, by the capability to measure strain, temperature and vibration. Load, strain, temperature and impact detection information can be incorporated into the turbine's monitoring or SCADA system and remote controlled by operators. Data analysis techniques allow dynamic maintenance scheduling to become a reality, what is of special interest for the cost-effective maintenance of large offshore or badly attainable onshore wind parks. To prove the feasibility of this sensor fusion on one optical fiber, interferences between both sensor systems are investigated and evaluated.

  3. Medication adherence: WHO cares?

    PubMed

    Brown, Marie T; Bussell, Jennifer K

    2011-04-01

    The treatment of chronic illnesses commonly includes the long-term use of pharmacotherapy. Although these medications are effective in combating disease, their full benefits are often not realized because approximately 50% of patients do not take their medications as prescribed. Factors contributing to poor medication adherence are myriad and include those that are related to patients (eg, suboptimal health literacy and lack of involvement in the treatment decision-making process), those that are related to physicians (eg, prescription of complex drug regimens, communication barriers, ineffective communication of information about adverse effects, and provision of care by multiple physicians), and those that are related to health care systems (eg, office visit time limitations, limited access to care, and lack of health information technology). Because barriers to medication adherence are complex and varied, solutions to improve adherence must be multifactorial. To assess general aspects of medication adherence using cardiovascular disease as an example, a MEDLINE-based literature search (January 1, 1990, through March 31, 2010) was conducted using the following search terms: cardiovascular disease, health literacy, medication adherence, and pharmacotherapy. Manual sorting of the 405 retrieved articles to exclude those that did not address cardiovascular disease, medication adherence, or health literacy in the abstract yielded 127 articles for review. Additional references were obtained from citations within the retrieved articles. This review surveys the findings of the identified articles and presents various strategies and resources for improving medication adherence.

  4. Effects of penicillin and erythromycin on adherence of invasive and noninvasive isolates of Streptococcus pyogenes to laminin.

    PubMed

    Šmitran, Aleksandra; Vuković, Dragana; Gajić, Ina; Marinković, Jelena; Ranin, Lazar

    2015-08-01

    This study investigated the possible relationship between the invasiveness of group A Streptococcus (GAS) strains and their abilities to adhere to laminin and assessed the effects of subinhibitory concentrations of penicillin and erythromycin on the ability of GAS to adhere to laminin. The adherence of noninvasive and highly invasive isolates of GAS to laminin was significantly higher than the adherence displayed by isolates of low invasiveness. Antibiotic treatment caused significant reductions in adherence to laminin in all three groups of strains. Penicillin was more successful in reducing the adherence abilities of the tested GAS strains than erythromycin.

  5. New technique for fabrication of low loss high temperature stable high reflectivity FBG sensor arrays

    NASA Astrophysics Data System (ADS)

    Mihailov, Stephen J.; Grobnic, Dan; Walker, Robert B.; Hnatovsky, Cyril A.; Ding, Huimin; Coulas, David; Lu, Ping

    2016-05-01

    Fiber Bragg gratings (FBG) arrays in silica based optical fibers are increasingly used in applications involving system monitoring in extreme high temperature environments. Where operational temperatures are < 600 °C, traditional UVlaser inscribed FBGs are not appropriate since the induced Type I index change is erased. Instead two competing FBG technologies exist: 1) regenerative FBGs resulting from high temperature annealing of a UV-laser written grating in a hydrogen loaded fiber and 2) FBGs written with femtosecond infrared pulse duration radiation (fs-IR), either using the point-by-point method or using the phase mask approach. Regenerative gratings possess low reflectivity and are cumbersome to produce, requiring high temperature processing in an oxygen free environment. Multiple pulse Type II femtosecond IR laser induced gratings made with a phase mask, while having very good thermal stability, also tend to have high insertion loss (~ 1dB/grating) limiting the number of gratings that can be concatenated in a sensor array. Recently it has been shown that during multiple pulse type II thermally stable fs-IR FBG production, two competing process occur: an initial induced fs-IR type I FBG followed by a thermally stable high insertion loss type II FBG. In this paper, we show that if only a type I FBG is written using type II intensity conditions but limited numbers of pulses and then annealed above 600 °C, the process results in a type II grating that is stable up to 1000 °C with very low insertion loss ideal for an FBG sensor array.

  6. FBG pressure sensor of high pressure electric oil pumps for prestressing

    NASA Astrophysics Data System (ADS)

    Guo, Zhenwu; Liu, Guangwei; Meng, Qingbin; Ge, Fuwei; Li, Weixiang

    2013-03-01

    Prestressed concrete structure is getting more and more extensive application in architecture, hydraulic engineering and traffic engineering because of its significant advantages of crack later or not cracks completely. It is an internal stress concrete structure that a certain force relies on prestressing tendons. The effectivity of the prestressing tendon in concrete structure is directly related to the reliability, applicability and viability of the whole concrete structure. So it is a key program to apply accurate prestress to the prestressing tendon. According to the pressure sensing principle of the fiber Bragg grating (FBG), a circular plate diaphragm-based FBG sensor for high pressure electric oil pumps that is the pressure source device of the prestressed concrete structure was presented. To overcome the cross sensitivity of temperature and pressure, two FBGs were integrated in the sensor, one of the FBGs isolated from the pressure is used as temperature compensation grating, it is called temperature-FBG comparing to another FBG called pressure-FBG. The elastic diaphragm was chosen as the pressure sensing element whose distortion displace is proportional to the difference of the two sides' pressure of the diaphragm. A certain stress is applied to the pressure-FBG which is stuck to the center of the diaphragm, and then the reflection wavelength of the pressure-FBG is inverse proportional to load of the diaphragm. The results indicated that the linearity is up to 99.99%, and the pressure sensitivity coefficient is 0.024nm/MPa within the measurement scope of 0-70MPa.

  7. Adherence to Insulin Therapy.

    PubMed

    Sarbacker, G Blair; Urteaga, Elizabeth M

    2016-08-01

    IN BRIEF Six million people with diabetes use insulin either alone or in combination with an oral medication. Many barriers exist that lead to poor adherence with insulin. However, there is an underwhelming amount of data on interventions to address these barriers and improve insulin adherence. Until pharmacological advancements create easier, more acceptable insulin regimens, it is imperative to involve patients in shared decision-making. PMID:27574371

  8. Demodulation of a fiber Bragg grating strain sensor by a multiwavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Cong, Shan; Sun, Yunxu; Zhao, Yuxi; Pan, Lifeng

    2012-04-01

    A fiber Bragg grating (FBG) sensors system utilizing a multi-wavelength erbium-doped fiber lasers (EDFL) with frequency shifter is proposed. The system is one fiber laser cavity with two FBG sensors as its filters. One is for strain sensing, and the other one is for temperature compensation. A frequency shifter is used to suppress the mode competition to lase two wavelengths that correspond with FBGs. The wavelength shift of the EDFL represents the sensing quantity, which is demodulated by Fiber Fabry-Perot (FFP) filter. The sensor's response to strain is measured by experiment. Because of exploiting the dual-wavelength fiber laser with a frequency shifter forming the feedback as the light source, many advantages of this system are achieved, especially high signal-to-noise ratio, high detected power, and low power consuming comparing with conventional FBG sensor system utilizing broadband light as the light source. What's more, this structure is also easy to combine with FBG array.

  9. Demodulation of a fiber Bragg grating strain sensor by a multiwavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Cong, Shan; Sun, Yunxu; Zhao, Yuxi; Pan, Lifeng

    2011-11-01

    A fiber Bragg grating (FBG) sensors system utilizing a multi-wavelength erbium-doped fiber lasers (EDFL) with frequency shifter is proposed. The system is one fiber laser cavity with two FBG sensors as its filters. One is for strain sensing, and the other one is for temperature compensation. A frequency shifter is used to suppress the mode competition to lase two wavelengths that correspond with FBGs. The wavelength shift of the EDFL represents the sensing quantity, which is demodulated by Fiber Fabry-Perot (FFP) filter. The sensor's response to strain is measured by experiment. Because of exploiting the dual-wavelength fiber laser with a frequency shifter forming the feedback as the light source, many advantages of this system are achieved, especially high signal-to-noise ratio, high detected power, and low power consuming comparing with conventional FBG sensor system utilizing broadband light as the light source. What's more, this structure is also easy to combine with FBG array.

  10. Fabrication and characterisation of FBG sensors in low loss polymer optical fibre

    NASA Astrophysics Data System (ADS)

    Lacraz, Amédée.; Theodosiou, Andreas; Polis, Michalis; Kalli, Kyriacos

    2016-05-01

    In this paper, we report on an effective way to locally alter the refractive index of a low-loss polymer optical fibre (POF), in order to fabricate novel fibre optical sensors. Such refractive index modifications, if reproduced periodically, create fibre Bragg gratings (FBGs) that find diverse applications in telecommunications and sensing. With a femtosecond laser set-up, we were able to inscribe refractive index changes in the core of the fibre on an area as small as a μm2. This technique can be effectively used to produce FBGs with a tailored length and strength and, so, with desired optical properties. The fibre used was a large core, graded index, multimode perfluorinated fibre. FBGs resonate at different wavelengths depending on the mode distribution in multimode fibres, because the effective refractive index depends on the spatial distribution of the light inside the core. Therefore, the reflection spectrum from the grating degenerates into multiple resonances, each associated with a different mode. The detection of the reflected modes was performed with a custom made software that was able to track a specific reflected mode even when the FBG underwent perturbation, such as temperature or strain changes. Moreover, a key advantage of low-loss fibre is the possibility to use long lengths of fibre and to be able to inscribe several FBGs in a single piece of fibre. With our detection system, we managed to track the perturbation of individual FBGs in a fibre array of multiple gratings. The combination of our femtosecond inscription setup and a mode detection system is encouraging for the development of low loss POF sensing devices.

  11. Monitoring of fatigue damage in composite lap-joints using guided waves and FBG sensors

    NASA Astrophysics Data System (ADS)

    Karpenko, Oleksii; Khomenko, Anton; Koricho, Ermias; Haq, Mahmoodul; Udpa, Lalita

    2016-02-01

    Adhesive bonding is being increasingly employed in many applications as it offers possibility of light-weighting and efficient multi-material joining along with reduction in time and cost of manufacturing. However, failure initiation and progression in critical components like joints, specifically in fatigue loading is not well understood, which necessitates reliable NDE and SHM techniques to ensure structural integrity. In this work, concurrent guided wave (GW) and fiber Bragg grating (FBG) sensor measurements were used to monitor fatigue damage in adhesively bonded composite lap-joints. In the present set-up, one FBG sensor was strategically embedded in the adhesive bond-line of a lap-joint, while two other FBGs were bonded on the surface of the adherends. Full spectral responses of FBG sensors were collected and compared at specific intervals of fatigue loading. In parallel, guided waves were actuated and sensed using PZT wafers mounted on the composite adherends. Experimental results demonstrated that time-of-flight (ToF) of the fundamental modes transmitted through the bond-line and spectral response of FBG sensors were sensitive to fatigue loading and damage. Combination of guided wave and FBG measurements provided the desired redundancy and synergy in the data to evaluate the degradation in bond-line properties. Measurements taken in the presence of continuously applied load replicated the in-situ/service conditions. The approach shows promise in understanding the behavior of bonded joints subjected to complex loading.

  12. Concept and design of an FBG emulator for a scanning laser-based fiber optic interrogator

    NASA Astrophysics Data System (ADS)

    Kuhenuri, Nader; Putzer, Philipp; Koch, Alexander W.; Obermaier, Johannes; Schweyer, Sebastian; Hurni, Andreas

    2014-06-01

    The Hybrid Sensor Bus is a space-borne temperature monitoring system for telecommunication satellites com­ bining electrical and fiber-optical Fiber Bragg Grating (FBG) sensors. Currently, there is no method available for testing the functionality and robustness of the system without setting up an actual sensor-network implying numerous FBG sensors in which each has to be heated/cooled individually. As a verification method of the mentioned system, FBG reflection based scanning laser interrogator, an FBG­ emulator is implemented to emulate the necessary FBG sensors. It is capable of immediate emulation of any given FBG spectrum, thus, any temperature. The concept provides advantages like emulating different kinds of FBGs with any peak shape, variable Bragg-wavelength λB, maximal-reflectivity τmax, spectral-width and degradation characteristics. Further, it facilitates an efficient evaluation of different interrogator peak-finding algorithms and the capability of emulating up to 10000 sample points per second is achieved. In the present paper, different concepts will be discussed and evaluated yielding to the implementation of a Variable Optical Attenuator (VOA) as the main actuator of the emulator. The actuator choice is further restricted since the emulator has to work with light in unknown polarization state. In order to implement a fast opto-ceramic VOA, issues like temperature dependencies, up to 200 V driving input and capacitive load have to be overcome. Furthermore, a self-calibration procedure mitigates problems like attenuation losses and long-term drift.

  13. High-strain fiber bragg gratings for structural fatigue testing of military aircraft

    NASA Astrophysics Data System (ADS)

    Davis, Claire; Tejedor, Silvia; Grabovac, Ivan; Kopczyk, James; Nuyens, Travis

    2012-09-01

    This paper reports on an experimental program of work which investigates the reliability, durability, and packaging of fiber Bragg gratings (FBGs) for application as distributed strain sensors during structural fatigue testing of military platforms. The influence of the FBG fabrication process on sensor reliability is investigated. In addition, methodologies for broad-area packaging and surface-mounting of FBG sensing arrays to defense platforms are developed and tested.

  14. Noise reduction of FBG sensor signal by using a wavelet transform

    NASA Astrophysics Data System (ADS)

    Cho, Yo-Han; Song, Minho

    2011-05-01

    We constructed a FBG (fiber Bragg grating) sensor system based on a fiber-optic Sagnac interferometer. A fiber-optic laser source is used as a strong light source to attain high signal-to-noise ratio. However the unstable output power and coherence noises of the fiber laser made it hard to separate the FBG signals from the interference signals of the fiber coils. To reduce noises and extract FBG sensor signals, we used a Gaussian curve-fitting and a wavelet transform. The wavelet transform is a useful tool for analyzing and denoising output signals. The feasibility of the wavelet transform denoising process is presented with the preliminary experimental results, which showed much better accuracy than the case with only the Gaussian curve-fitting algorithm.

  15. Fully distributed chirped FBG sensor and application in laser-induced interstitial thermotherapy

    NASA Astrophysics Data System (ADS)

    Li, Chenglin; Chen, Na; Chen, Zhenyi; Wang, Tingyun

    2009-11-01

    In the laser induced interstitial thermotherapy (LITT), real-timely detecting the temperature distribution of the cured tissue is a bottleneck. In this paper, a fully distributed chirped Fiber Bragg grating (FBG) sensor, which is of small size, immune from electromagnetic interference (EMI) and high sensitivity, is proposed to solve this problem. An experiment simulation of LITT is set up, and only one chirped FBG is used to detect the dynamic spectral variation with different laser power. Meanwhile, a high-efficiency spectra inversion algorithm named MSAE of FBG is utilized to demodulate the system and obtain the temperature distribution. The spatial resolution is 0.25mm and the running time of demodulation is tens of seconds, which can help doctors control the laser parameters such as the laser power and the treatment time to guarantee the security of the therapy.

  16. Non-contact FBG sensing based steam turbine rotor dynamic balance vibration detection system

    NASA Astrophysics Data System (ADS)

    Li, Tianliang; Tan, Yuegang; Cai, Lin

    2015-10-01

    This paper has proposed a non-contact vibration sensor based on fiber Bragg grating sensing, and applied to detect vibration of steam turbine rotor dynamic balance experimental platform. The principle of the sensor has been introduced, as well as the experimental analysis; performance of non-contact FBG vibration sensor has been analyzed in the experiment; in addition, turbine rotor dynamic vibration detection system based on eddy current displacement sensor and non-contact FBG vibration sensor have built; finally, compared with results of signals under analysis of the time domain and frequency domain. The analysis of experimental data contrast shows that: the vibration signal analysis of non-contact FBG vibration sensor is basically the same as the result of eddy current displacement sensor; it verified that the sensor can be used for non-contact measurement of steam turbine rotor dynamic balance vibration.

  17. Low velocity impact localization system using FBG array and MVDR beamforming algorithm

    NASA Astrophysics Data System (ADS)

    Sai, Yaozhang; Jiang, Mingshun; Sui, Qingmei; Jia, Lei; Lu, Shizeng

    2015-12-01

    This paper proposes an impact localization system based on the fiber Bragg grating (FBG) array and minimum variance distortionless response (MVDR) beamforming algorithm. The linear FBG array, which contains seven FBG sensors, is used for detecting impact signals. Morlet wavelet transform is applied for extracting narrow-band signals of impact signals. According to the MVDR beamforming algorithm, the system realizes single-impact and multi-impact localizations. The localization system is verified on a 500 mm×500 mm×2 mm carbon fiber reinforced polymer (CFRP) plate for single-impact and multi-impact localizations. The average locating error and the maximum locating error are 6.8 mm and 9.9 mm, respectively.

  18. Effects of the inclined femto laser incidence at the phase mask on FBG carving

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Wu, Shengli; Zhang, Jintao; Ren, Wenyi

    2015-12-01

    The inclined incidence of the femto laser on the phase mask in fiber Bragg grating (FBG) carving has a significant effect on the quality of FBG fabrication. Based on that the infrared femto laser has highly spatial coherence and the order walk-off will happen behind the phase mask, the interferogram generated at the fiber core by the inclined femto laser beam has been analyzed using the multi-beam interference principle. The influence of beam inclination on the coherence of the 0th and ± 1st orders diffraction with different exposure distance, the visibility of interferogram and the frequency component of the transverse interferogram intensity has also been analyzed. It is meaningful for the FBG fabricating with the femto laser.

  19. Adherence to Sublingual Immunotherapy.

    PubMed

    Incorvaia, Cristoforo; Mauro, Marina; Leo, Gualtiero; Ridolo, Erminia

    2016-02-01

    Adherence is a major issue in any medical treatment. Allergen immunotherapy (AIT) is particularly affected by a poor adherence because a flawed application prevents the immunological effects that underlie the clinical outcome of the treatment. Sublingual immunotherapy (SLIT) was introduced in the 1990s, and the early studies suggested that adherence and compliance to such a route of administration was better than the traditional subcutaneous route. However, the recent data from manufacturers revealed that only 13% of patients treated with SLIT reach the recommended 3-year duration. Therefore, improved adherence to SLIT is an unmet need that may be achieved by various approaches. The utility of patient education and accurate monitoring during the treatment was demonstrated by specific studies, while the success of technology-based tools, including online platforms, social media, e-mail, and a short message service by phone, is currently considered to improve the adherence. This goal is of pivotal importance to fulfill the object of SLIT that is to modify the natural history of allergy, ensuring a long-lasting clinical benefit, and a consequent pharmaco-economic advantage, when patients complete at least a 3-year course of treatment. PMID:26758865

  20. Adherence to HEp-2 cells and enteropathogenic potential of Aeromonas spp.

    PubMed

    Grey, P A; Kirov, S M

    1993-04-01

    Aeromonas strains (total = 60) of clinical, water and food origin were tested for adherence to HEp-2 cells. Environmental strains were selected (except for A. caviae) to include primarily those expressing other virulence-associated properties. Adhesion was markedly species-dependent (A. veronii biotype sobria, 15 of 26 [58%]. A caviae, 4 of 12 [33%] and A. hydrophila, 2 of 8 [11%]). A. veronii biotype sobria were adhesive, irrespective of source (62 and 54% for clinical and environmental strains, respectively). Adherent strains of this species were enterotoxin-positive and most (13 of 15) grew at 43 degrees C. A. caviae isolated from clinical specimens contained a higher proportion (75%) of adherent strains than environmental strains (13%). Virulent subsets of A. veronii biotype sobria and A. caviae are adherent to HEp-2 cells. The HEp-2 assay is a useful model for investigating mechanisms of adherence and enteropathogenicity of virulent Aeromonas species.

  1. Self-compensated high-speed FBG interrogation using closed-loop tracking system

    NASA Astrophysics Data System (ADS)

    Kempen, Lothar U.; Mendoza, Edgar A.; Saxena, Indu F.

    2007-09-01

    A system for interrogation of high-frequency events with an FBG array in the presence of large quasi-static fluctuations has been developed at Intelligent Optical Systems (IOS). The system allows highly sensitive detection of periodic or transient events up to the MHz range while automatically compensating for slow changes in the FBG center frequency using a closed loop tracking system. Both the high frequency signal and the low frequency parts of the sensor spectrum are available for further processing. The system components, setup, and applications are presented and discussed.

  2. Research of difference absorption optical fiber CO gas sensor based on FBG

    NASA Astrophysics Data System (ADS)

    Wang, Yanju; Liu, Zhihua; Kang, Yueyi; Wang, Yutian

    2009-07-01

    Based on analysis of the near infrared spectral absorption of CO molecule and considering factors such as compatibility with the transmission characteristics of silica optical fiber and the price, a kind of allfiber remote sensor utilizing Fiber Bragg Grating(FBG) filters and 1.567μm high power light-emitting diode (LED) was developed for real time absorption measurement. FBG has a low insert loss and can be produced easily compared with dielectric interference filters. Theory and experiment proved that the system has simple construct and high sensibility.

  3. Adherence to treatment in adolescents

    PubMed Central

    Taddeo, Danielle; Egedy, Maud; Frappier, Jean-Yves

    2008-01-01

    Health care professionals must be alert to the high prevalence of low adherence to treatment during adolescence. Low adherence increases morbidity and medical complications, contributes to poorer quality of life and an overuse of the health care system. Many different factors have an impact on adherence. However, critical factors to consider in teens are their developmental stage and challenges, emotional issues and family dysfunction. Direct and indirect methods have been described to assess adherence. Eliciting an adherence history is the most useful way for clinicians to evaluate adherence, and could be the beginning of a constructive dialogue with the adolescent. Interventions to improve adherence are multiple – managing mental health issues appropriately, building a strong relationship, customizing the treatment regimen if possible, empowering the adolescent to deal with adherence issues, providing information, ensuring family and peer support, and motivational enhancement therapy. Evaluation of adherence at regular intervals should be an important aspect of health care for adolescents. PMID:19119348

  4. Design and application of a fiber Bragg grating strain sensor with enhanced sensitivity in the small-scale dam model

    NASA Astrophysics Data System (ADS)

    Ren, Liang; Chen, Jianyun; Li, Hong-Nan; Song, Gangbing; Ji, Xueheng

    2009-03-01

    Accurate measurement of strain variation and effective prediction of failure within models have been major objectives for strain sensors in dam model tests. In this paper, a fiber Bragg grating (FBG) strain sensor with enhanced strain sensitivity that is packaged by two gripper tubes is presented and applied in the seismic tests of a small-scale dam model. This paper discusses the principle of enhanced sensitivity of the FBG strain sensor. Calibration experiments and reliability tests were conducted to evaluate the sensor's strain transferring characteristics on plates of different material. This paper also investigates the applicability of the FBG strain sensors in seismic tests of a dam model by conducting a comparison between the test measurements of FBG sensors and analytical predictions, monitoring the failure progress and predicting the cracking inside the dam model. Results of the dam model tests prove that the FBG strain sensor has the advantages of small size, high precision, and embeddability. It has a promising potential in the cracking and failure monitoring and identification of the dam model.

  5. Experimental qualification by extensive evaluation of fibre optic strain sensors

    NASA Astrophysics Data System (ADS)

    Schilder, Constanze; Kusche, Nadine; Schukar, Vivien G.; Münzenberger, Sven; Habel, Wolfgang R.

    2013-09-01

    Fibre optic strain sensors used in practical applications have to provide reliable measurements. Therefore, the applied sensor and the sensor systems must be validated experimentally. This can be achieved with facilities which use physically independent measurement systems in order to avoid the influences caused by the application of a reference sensor. This paper describes the testing methods of the specially developed validation facility KALFOS for the qualification and evaluation of surface-applied strain sensors. For reliable sensor results, the performance of fibre optic strain patches with and without FBG under combined thermal and mechanical loading was investigated. Additionally, the strain gauge factor of the fibre optic strain patches with FBG was determined experimentally and compared to the specified strain gauge factor. These results will be the basis for the development of guidelines and standards concerning the application of the sensors.

  6. Evaluation of the performance of orthodontic devices using FBG sensors

    NASA Astrophysics Data System (ADS)

    Carvalho, L.; Roriz, P.; Frazão, O.; Marques, M. B.

    2015-04-01

    Cross-bite, as a malocclusion effect, is defined as a transversal changing of the upper dental arch, in relation to the lower arch, and may be classified as skeletal, dental or functional. As a consequence, the expansion of maxilla is an effective clinical treatment used to correct transversal maxillary discrepancy. The maxillary expansion is an ancient method used in orthodontics, for the correction of the maxillary athresia with posterior crossbite, through the opening of the midpalatal suture (disjunction), using orthodontic- orthopaedic devices. Same controversial discussion arises among the clinicians, about the effects of each orthodontic devices as also about the technique to be employed. The objective of this study was to compare the strain field induced by two different orthodontic devices, named disjunctor with and without a connecting bar, in an acrylic model jaw, using fiber Bragg grating sensors to measure the strain patterns. The orthodontic device disjunctor with the bar, in general, transmits higher forces and strain to teeth and maxillae, than with the disjunctor without bar. It was verified that the strain patterns were not symmetric between the left and the right sides as also between the posterior and anterior regions of the maxillae. For the two devices is also found that in addition a displacement in the horizontal plane, particularly in posterior teeth, also occurs a rotation corresponding to a vestibularization of the posterior teeth and their alveolar processes.

  7. Temperature insensitive magnetic field sensor based on an etched TCFMI cascaded with a FBG

    NASA Astrophysics Data System (ADS)

    Yan, Guofeng; Zhang, Liang; He, Sailing

    2015-08-01

    In this paper, a dual-parameter measurement scheme based on an etched thin core fiber modal interferometer (TCMI) cascaded with a fiber Bragg grating (FBG) is proposed and experimentally demonstrated for simultaneous measurement of magnetic field and temperature. The magnetic fluid cladding surrounding the TCFMI was used as a magnetic field-to-refractive index transducer. To depress the temperature influence on the performance of such sensors, an FBG was inscribed in the leading SMF of the TCFMI. Experimental results show that, the reflection of the FBG has a magnetic field intensity and temperature sensitivities of -0.017 dB/Oe and 0.133 dB/°, respectively, while the Bragg wavelength of the FBG only has a temperature sensitivity of 13.23 pm/°. By monitoring the reflection wavelength and intensity of the Bragg mode, the intensity of the magnetic field and the temperature variance can be measured, which enables magnetic field sensing under strict temperature environments. Meanwhile the reflective sensing probe is more compact and practical for applications in hard-to-reach conditions.

  8. Enhanced strain and temperature sensing by reduced graphene oxide coated etched fiber Bragg gratings.

    PubMed

    S, Sridevi; Vasu, K S; Asokan, S; Sood, A K

    2016-06-01

    This Letter reports on an etched fiber Bragg grating (eFBG) sensor coated with reduced graphene oxide (RGO) having enhanced sensitivity for physical parameters such as strain and temperature. The synergetic effect of the changes in grating pitch and refractive index of RGO with change in temperature or strain enhances the shift in Bragg wavelength (λB). The RGO-coated eFBG sensors exhibit a strain sensitivity of 5.5 pm/μϵ (∼5 times that of bare fiber Bragg gratings) and temperature sensitivity of 33 pm/°C (∼3 times that of bare fiber Bragg gratings). The resolutions of ∼1  μϵ and ∼0.3°C have been obtained for strain and temperature respectively, using RGO-coated eFBG sensors. PMID:27244425

  9. Enhanced strain and temperature sensing by reduced graphene oxide coated etched fiber Bragg gratings.

    PubMed

    S, Sridevi; Vasu, K S; Asokan, S; Sood, A K

    2016-06-01

    This Letter reports on an etched fiber Bragg grating (eFBG) sensor coated with reduced graphene oxide (RGO) having enhanced sensitivity for physical parameters such as strain and temperature. The synergetic effect of the changes in grating pitch and refractive index of RGO with change in temperature or strain enhances the shift in Bragg wavelength (λB). The RGO-coated eFBG sensors exhibit a strain sensitivity of 5.5 pm/μϵ (∼5 times that of bare fiber Bragg gratings) and temperature sensitivity of 33 pm/°C (∼3 times that of bare fiber Bragg gratings). The resolutions of ∼1  μϵ and ∼0.3°C have been obtained for strain and temperature respectively, using RGO-coated eFBG sensors.

  10. Field monitoring of static, dynamic, and statnamic pile loading tests using fibre Bragg grating strain sensors

    NASA Astrophysics Data System (ADS)

    Li, Jin; Correia, Ricardo P.; Chehura, Edmon; Staines, Stephen; James, Stephen W.; Tatam, Ralph; Butcher, Antony P.; Fuentes, Raul

    2009-10-01

    Pile loading test plays an important role in the field of piling engineering. In order to gain further insight into the load transfer mechanism, strain gauges are often used to measure local strains along the piles. This paper reports a case whereby FBG strain sensors was employed in a field trial conducted on three different types of pile loading tests in a glacial till. The instrumentation systems were configured to suit the specific characteristic of each type of test. Typical test results are presented. The great potential of using FBG sensors for pile testing is shown.

  11. Filamentous hemagglutinin has a major role in mediating adherence of Bordetella pertussis to human WiDr cells.

    PubMed Central

    Urisu, A; Cowell, J L; Manclark, C R

    1986-01-01

    [35S]methionine-labeled Bordetella pertussis adhered to monolayers of WiDr cells, an epitheliumlike cell line from a human intestinal carcinoma. Adherence was proportional to the density of the WiDr cells and to the concentration of B. pertussis in the assay. Adherence of virulent phase I strains Tohama phase I, 114, and BP338 was much greater than adherence of avirulent strains Tohama phase III and 423 phase IV. Mutants deficient in the production of the filamentous hemagglutinin (FHA) were hemagglutination negative and adhered to WiDr cells much less efficiently than the parent strains. Preincubation of B. pertussis cells with FHA increased their hemagglutination activity and adherence to WiDr cells. Goat antibody to FHA inhibited, in a dose-dependent manner, the adherence of strain Tohama I but not the adherence of FHA-deficient mutant Tohama 325. At similar protein concentrations, normal goat antibody, goat antibody to pertussis toxin, or the Fab fragments of goat antibody to serotype 2 fimbriae had no effect on adherence. Also, an FHA-positive strain without fimbriae showed high adherence, while a fimbriated FHA-deficient mutant adhered poorly. Our data indicate that FHA plays a major role in adherence of B. pertussis to human WiDr cells. Fimbriae do not appear to mediate attachment of B. pertussis to WiDr cells. PMID:2872165

  12. A soft self-repairing for FBG sensor network in SHM system based on PSO-SVR model reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoli; Wang, Peng; Liang, Dakai; Fan, Chunfeng; Li, Cailing

    2015-05-01

    Structural health monitoring (SHM) system takes advantage of an array of sensors to continuously monitor a structure and provide an early prediction such as the damage position and damage degree etc. Such a system requires monitoring the structure in any conditions including bad condition. Therefore, it must be robust and survivable, even has the self-repairing ability. In this study, a model reconstruction predicting algorithm based on particle swarm optimization-support vector regression (PSO-SVR) is proposed to achieve the self-repairing of the Fiber Bragg Grating (FBG) sensor network in SHM system. Furthermore, an eight-point FBG sensor SHM system is experimented in an aircraft wing box. For the damage loading position prediction on the aircraft wing box, six kinds of disabled modes are experimentally studied to verify the self-repairing ability of the FBG sensor network in the SHM system, and the predicting performance are compared with non-reconstruction based on PSO-SVR model. The research results indicate that the model reconstruction algorithm has more excellence than that of non-reconstruction model, if partial sensors are invalid in the FBG-based SHM system, the predicting performance of the model reconstruction algorithm is almost consistent with that no sensor is invalid in the SHM system. In this way, the self-repairing ability of the FBG sensor is achieved for the SHM system, such the reliability and survivability of the FBG-based SHM system is enhanced if partial FBG sensors are invalid.

  13. Medication adherence: process for implementation

    PubMed Central

    Mendys, Phil; Zullig, Leah L; Burkholder, Rebecca; Granger, Bradi B; Bosworth, Hayden B

    2014-01-01

    Improving medication adherence is a critically important, but often enigmatic objective of patients, providers, and the overall health care system. Increasing medication adherence has the potential to reduce health care costs while improving care quality, patient satisfaction and health outcomes. While there are a number of papers that describe the benefits of medication adherence in terms of cost, safety, outcomes, or quality of life, there are limited reviews that consider how best to seamlessly integrate tools and processes directed at improving medication adherence. We will address processes for implementing medication adherence interventions with the goal of better informing providers and health care systems regarding the safe and effective use of medications. PMID:25114513

  14. Dynamic Response and Signal to Noise Ratio Investigation of NIR-FBG Dynamic Sensing System for Monitoring Thin- walled Composite Plate

    NASA Astrophysics Data System (ADS)

    Hafizi, Z. M.; Epaarachchi, J.

    2015-12-01

    Optical fiber systems for dynamic response measurement become an attractive study nowadays especially in the field of Structural Health Monitoring (SHM). This work presents the investigation of an optical fiber sensor system utilizing Near Infra-Red Fiber Bragg Grating (NIR-FBG) sensor for SHM of a thin-walled composite structure. In this study, a comparison between the experimental result and simulation study using finite element analysis has been presented. By comparing both results, the FBG dynamic sensing system was shown to have an excellent capability in acquiring dynamic response due to flexural wave propagations. In the meantime, a signal to noise ratio (SNR) study was also performed to several FBG dynamic sensor systems; particularly to see the comparison between NIR-FBG sensor and 1550 nm FBG sensor. Furthermore, with a proper configuration, an NIR-FBG system was proved to have better performance than the 1550 nm based FBG sensor.

  15. High resolution strain sensor for earthquake precursor observation and earthquake monitoring

    NASA Astrophysics Data System (ADS)

    Zhang, Wentao; Huang, Wenzhu; Li, Li; Liu, Wenyi; Li, Fang

    2016-05-01

    We propose a high-resolution static-strain sensor based on a FBG Fabry-Perot interferometer (FBG-FP) and a wavelet domain cross-correlation algorithm. This sensor is used for crust deformation measurement, which plays an important role in earthquake precursor observation. The Pound-Drever-Hall (PDH) technique based on a narrow-linewidth tunable fiber laser is used to interrogate the FBG-FPs. A demodulation algorithm based on wavelet domain cross-correlation is used to calculate the wavelength difference. The FBG-FP sensor head is fixed on the two steel alloy rods which are installed in the bedrock. The reference FBG-FP is placed in a strain-free state closely to compensate the environment temperature fluctuation. A static-strain resolution of 1.6 n(epsilon) can be achieved. As a result, clear solid tide signals and seismic signals can be recorded, which suggests that the proposed strain sensor can be applied to earthquake precursor observation and earthquake monitoring.

  16. Reflective SOA fiber cavity adaptive laser source for measuring dynamic strains

    NASA Astrophysics Data System (ADS)

    Wei, Heming; Tao, Chuanyi; Krishnaswamy, Sridhar

    2016-04-01

    Smart sensors based on Optical fiber Bragg gratings (FBGs) are suitable for structural health monitoring of dynamic strains in civil, aerospace, and mechanical structures. In these structures, dynamic strains with high frequencies reveal acoustic emissions cracking or impact loading. It is necessary to find a practical tool for monitoring such structural damages. In this work, we explore an intelligent system based on a reflective semiconductor optical amplifier (RSOA)- FBG composed as a fiber cavity for measuring dynamic strain in intelligent structures. The ASE light emitted from a RSOA laser and reflected by a FBG is amplified in the fiber cavity and coupled out by a 90:10 coupler, which is demodulated by a low frequency compensated Michelson interferometer using a proportional-integral-derivative (PID) controller and is monitored via a photodetector. As the wavelength of the FBG shifts due to dynamic strain, the wavelength of the optical output from the laser cavity shifts accordingly, which is demodulated by the Michelson Interferometer. Because the RSOA has a quick transition time, the RSOA- FBG fiber cavity shows an ability of high frequency response to the FBG reflective spectrum shift, with frequency response extending to megahertz.

  17. A portable multi-function weight-in-motion (WIM) sensor system based on fiber Bragg grating (FBG) technology

    NASA Astrophysics Data System (ADS)

    Zhang, Hongtao; Wei, Zhanxiong; Zhao, Qiming; Guan, Liang; Zou, Jilin; Fan, Lingling; Yang, Shangming; Song, Dongcao; Recine, Gregory; Cui, Hong-Liang

    2008-04-01

    A portable, multi-function WIM sensing system based on Fiber Bragg Grating (FBG) technology is developed to measure the total weight, the distribution of weight of vehicle in motion (the weights of left front, right front, left rear and right rear wheels respectively), the distance of wheels axles and distance between left and right wheels. Currently the speed of vehicle to be tested can be up to 15 mph, the full scope of measurement for this system is 4000 lbs, and the static sensitivity of sensor head is 20 lbs. This system has been tested respectively at Stevens' campus and Army base. Compared to other schemes, our method has a number of advantages such as immune to electromagnetic interference, high repeatability, lightweight, low power consumption, high sensitivity to dynamic strain caused by load of vehicles in high-speed. The accuracy of whole system can be improved by simulating the mathematical model of sensor heads and improving the quality of manufacture as well as the calibration condition in the future.

  18. Up-taper-based Mach-Zehnder interferometer for temperature and strain simultaneous measurement.

    PubMed

    Kang, Zexin; Wen, Xiaodong; Li, Chao; Sun, Jiang; Wang, Jing; Jian, Shuisheng

    2014-04-20

    A novel all-fiber sensing configuration for simultaneous measurements of temperature and strain based on the up-taper Mach-Zehnder interferometer (MZI) with an in-line embedded fiber Bragg grating (FBG) is proposed and experimentally demonstrated. This configuration consists of two up-tapers fabricated by an excessive fusion splicing method and a short segment of inscribed FBG. Due to the different responses of the up-taper MZI and the FBG to the uniform variation of temperature and strain, the simultaneous measurement for these two variables could be achieved by real-time monitoring the transmission spectrum. For 0.01 nm wavelength resolution, a resolution of 0.311°C in temperature can be achieved, and the average strain resolution is 10.07 με. PMID:24787597

  19. Comparison of strain sensitivity of bare and structure-integrated fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Lebid, Solomija Y.; Hofmann, Detlef; Basedau, Frank; Daum, Werner

    2003-07-01

    For the last decade sensor architectures with embedded fibers found their application in large structure monitoring and proved their capability to replace existing techniques for monitoring of linear strain, temporary or permanent none-uniform strain and load, temperature, vibrations, bending, or complex strain-temperature, vibrations-temperature influences, etc. Such sensor architectures, called smart structures, use different sensing mechanisms, in one of which - fiber Bragg grating (FBG) - is applied as a sensitive element. Because of high sensitivity, absolute measurement ability, possibility to work reliable in adverse environment, such as electromagnetic fields, radiation, extreme temperature, and quick response time, FBGs are object of numerous research of leading laboratories worldwide. Some problems are still remaining in this field, although there have been some ways found to solve part of them. This paper discusses some aspects of different fixing mechanisms of FBG and provides evaluation and comparison of methods of FBG integration in sensor housing or in sensor architecture.

  20. Vibration monitoring of a helicopter blade model using the optical fiber distributed strain sensing technique.

    PubMed

    Wada, Daichi; Igawa, Hirotaka; Kasai, Tokio

    2016-09-01

    We demonstrate a dynamic distributed monitoring technique using a long-length fiber Bragg grating (FBG) interrogated by optical frequency domain reflectometry (OFDR) that measures strain at a speed of 150 Hz, spatial resolution of 1 mm, and measurement range of 20 m. A 5 m FBG is bonded to a 5.5 m helicopter blade model, and vibration is applied by the step relaxation method. The time domain responses of the strain distributions are measured, and the blade deflections are calculated based on the strain distributions. Frequency response functions are obtained using the time domain responses of the calculated deflection induced by the preload release, and the modal parameters are retrieved. Experimental results demonstrated the dynamic monitoring performances and the applicability to the modal analysis of the OFDR-FBG technique. PMID:27607270

  1. Materials Adherence Experiment: Technology

    SciTech Connect

    Jenkins, P.P.; Landis, G.A.; Oberle, L.G.

    1997-12-31

    NASA`s Mars Pathfinder mission, launched December 4, 1996, reflects a new philosophy of exploiting new technologies to reduce mission cost and accelerate the pace of space exploration. Pathfinder will demonstrate a variety of new technologies aimed at reducing the cost of Mars exploration. Chief among these will be the demonstration of a solar-powered spacecraft on the surface of Mars. The Materials Adherence Experiment on Pathfinder was designed to measure the degradation of solar arrays due to dust settling out of the atmosphere and blocking light to the solar array, lowering the array power output.

  2. Pulling on adhered vesicles

    NASA Astrophysics Data System (ADS)

    Smith, Ana-Suncana; Goennenwein, Stefanie; Lorz, Barbara; Seifert, Udo; Sackmann, Erich

    2004-03-01

    A theoretical model describing pulling of vesicles adhered in a contact potential has been developed. Two different regimes have been recognized. For weak to middle-strength adhesive potentials, locally stable shapes are found in a range of applied forces, separated from the free shape by an energy barrier. The phase diagram contains regions with either a unique bound shape or an additional meta-stable shape. Upon pulling, these shapes unbind discontinuously since the vesicle disengage from the surface while still possessing a finite adhesion area (Smith 2003a). In a strong adhesion regime, a competition between adhesion and tether formation is observed. A critical onset force is identified where a tether spontaneously appears as a part of a second order shape transition. Further growth of a tether is followed by a detachment process which terminates at a finite force when a vesicle continuously unbinds from the substrate (Smith 2003b). Both critical forces, as well as all shape parameters, are calculated as a function of the reduced volume and the strength of adhesive potential. Analogous experimental study has been performed where a vertical magnetic tweezers are used in combination with micro-interferometric and confocal techniques to reproduce the same symmetry as in the theoretical investigation. Giant vesicles are bound to the substrate by numerous specific bonds formed between ligands and receptors incorporated into the vesicle and the substrate, respectively. Application of a constant force is inducing a new thermodynamic equilibrium of the system where the vesicle is partially unbound from the substrate (Goennenwein 2003). The shapes of vesicles are compared prior and during application of the force. Very good agreement is obtained, particularly in the middle-strength adhesion regime (Smith 2003c). References: 1. A.-S. Smith, E. Sackmann, U. Seifert: Effects of a pulling force on the shape of a bound vesicle, Europhys. Lett., 64, 2 (2003). 2. A.-S. Smith

  3. Rockfall hazard alarm strategy based on FBG smart passive net structure

    NASA Astrophysics Data System (ADS)

    Li, Sheng; Ma, Junjie; Hu, Jun

    2015-03-01

    In order to realize working state remote monitoring for a passive net, alarm timely and correctly for the rockfall invasion, and solve the disadvantages in the existing means, such as needing power supply in situ, vulnerability to electromagnetic interference and environmental climate impact, a smart passive net structure based on the optical fiber sensing technology was designed which equipped with intercepting and sensing functions. The wire rope net as one part of the smart passive net was weaved with two kinds of optical fiber sensing elements, namely, fiber Bragg grating (FBG) perimeter severity sensors and optical fiber monitoring net with each end of the tail fiber containing an FBG probe. Based on the proposed smart structure, a combination alarm strategy for rockfall was proposed, which can distinguish transmission bug, whether the rockfall invasion or net broken occurs. Through a designed simulation test, the effectiveness of the proposed alarm strategy was certificated.

  4. Single-frequency Yb-doped fiber laser with distributed feedback based on a random FBG

    NASA Astrophysics Data System (ADS)

    Abdullina, S. R.; Vlasov, A. A.; Lobach, I. A.; Belai, O. V.; Shapiro, D. A.; Babin, S. A.

    2016-07-01

    Single-frequency operation of a 1.03 μm fiber laser with random distributed feedback (RDFB) is demonstrated. The laser cavity is based on a 4 cm long fiber Bragg grating (FBG) consisting of 10 homogeneous subgratings with random phase and amplitude of refractive index modulation inscribed in a polarization maintaining (PM) Yb-doped fiber. Such RDFB laser generates single longitudinal mode with output power up to 25 mW, which is 3.5 times higher than that for a DFB laser based on regular π-shifted FBG of the same length in the same fiber. The single-frequency linewidth is measured to be  <100 kHz in both cases. The observed difference of the DFB and RDFB lasers is confirmed by numerical simulation showing different longitudinal distribution of intra-cavity radiation in these cases, analogous to those in the experiment.

  5. Fiber-optic ultrasonic sensing systems using PS-FBG for damage monitoring in composite materials

    NASA Astrophysics Data System (ADS)

    Okabe, Yoji; Wu, Qi

    2015-07-01

    Fiber-optic ultrasonic sensing systems have been developed for structural health monitoring of composite structures by introduction of phase-shifted fiber Bragg gratings (PS-FBGs). The systems can achieve the compatibility of high sensitivity and broadband performance. First, PS-FBG balanced sensing system was developed and succeeded in detection of small acoustic emission signals of composite laminates. Next, erbium fiber ring laser sensing system with inbuilt PS-FBG was developed. This system has high robustness due to its self-adjustment function for environmental disturbances and achieved much higher sensitivity and ultra-broadband respondency than piezoelectric ceramic sensors. These systems have large potential to realize the ultrasonic SHM.

  6. Acoustic emission location on aluminum alloy structure by using FBG sensors and PSO method

    NASA Astrophysics Data System (ADS)

    Lu, Shizeng; Jiang, Mingshun; Sui, Qingmei; Dong, Huijun; Sai, Yaozhang; Jia, Lei

    2016-04-01

    Acoustic emission location is important for finding the structural crack and ensuring the structural safety. In this paper, an acoustic emission location method by using fiber Bragg grating (FBG) sensors and particle swarm optimization (PSO) algorithm were investigated. Four FBG sensors were used to form a sensing network to detect the acoustic emission signals. According to the signals, the quadrilateral array location equations were established. By analyzing the acoustic emission signal propagation characteristics, the solution of location equations was converted to an optimization problem. Thus, acoustic emission location can be achieved by using an improved PSO algorithm, which was realized by using the information fusion of multiple standards PSO, to solve the optimization problem. Finally, acoustic emission location system was established and verified on an aluminum alloy plate. The experimental results showed that the average location error was 0.010 m. This paper provided a reliable method for aluminum alloy structural acoustic emission location.

  7. Improvement of FBG peak wavelength demodulation using digital signal processing algorithms

    NASA Astrophysics Data System (ADS)

    Harasim, Damian; Gulbahar, Yussupova

    2015-09-01

    Spectrum reflected or transmitted by fiber Bragg grating (FBG) in laboratory environment usually has smooth shape with high signal to noise ratio, similar to Gaussian curve. However, in some applications reflected spectrum could included some strong noise, especially where sensing array contains large number of FBGs or while is used broadband, low power source. This paper presents a possibility for extraction fiber Bragg grating peak wavelength from spectra with weak signal to noise radio with most frequently using digital signal processing algorithms. The accuracy of function minimum, centroid and Gaussian fitting methods for peak wavelength detection is compared. The linearity of processing characteristics of extended FBG measured for reference high power and second, low power source is shown and compared.

  8. A novel MUX/DEMUX based on few-mode FBG for mode division multiplexing system

    NASA Astrophysics Data System (ADS)

    Han, Yueyu; Hu, Guijun

    2016-05-01

    In this paper, a novel mode multiplexer/demultiplexer (MUX/DEMUX) based on few-mode fiber Bragg gratings (FBG) has been proposed. The principle of the MUX/DEMUX based on few-mode FBG has been described in detail, and crosstalk of better than -20 dB is obtained experimentally. Then a 2×2 division multiplexing (MDM) system has been established with the MUX/DEMUX we proposed. The transmission experiment of 2×10 Gbps PRBS has been achieved successfully, which are carried by LP01 mode and LP11 mode, respectively. When the receiver sensitivity is greater than -14 dB m and -10 dB m, the BER can both reach 10-3 for B2B and 10 km transmission, respectively.

  9. CFRP damage identification system based on FBG sensors and ELM method

    NASA Astrophysics Data System (ADS)

    Lu, Shizeng; Jiang, Mingshun; Jia, Lei; Sui, Qingmei; Sai, Yaozhang

    2015-02-01

    The identification of the damage state of Carbon fiber-reinforced plastic (CFRP) structure is the necessary information for ensuring the safety of CFRP structure. In this paper, the structural damage identification system using fiber Bragg grating (FBG) sensors and the damage identification method were investigated. FBG sensors were used to detect the structural dynamic response signal, which was generated by an active actuation way. Fourier transform and principal component analysis (PCA) were used to extract the damage characteristic. After that, the structural damage identification model was constructed based on extreme learning machine (ELM), whose input is the damage characteristic and output is the damage state. Finally, the damage identification system was established and verified on a CFRP plate with 160 mm160 mm experiment area. The experimental results showed that the identification accuracy was more than 90 %. This paper provided a reliable method for CFRP structural damage identification.

  10. Cable television monitoring system based on fiber laser and FBG sensor

    NASA Astrophysics Data System (ADS)

    Peng, Peng-Chun; Huang, Jun-Han; Wu, Shin-Shian; Yang, Wei-Yuan; Shen, Po-Tso

    2015-05-01

    We propose and experimentally demonstrate a cable television monitoring system based on a linear-cavity fiber laser and fiber Bragg grating (FBG) sensors. The linear-cavity fiber laser comprises a hybrid amplifier with an erbium-doped fiber amplifier and a semiconductor optical amplifier, a fiber loop mirror with a polarization controller and an optical coupler as a cavity mirror, and the FBG sensors acting as another cavity mirrors. Experimental results showed the feasibility of the monitoring system with sufficient of signal-to-noise ratio over 30 dB and stable output power, and the link of cable television signals on fiber link can monitored in real time. Excellent performances of carrier-to-noise ratio after long-distance transmission are obtained for cable television applications.

  11. In-vivo determination of chewing patterns using FBG and artificial neural networks

    NASA Astrophysics Data System (ADS)

    Pegorini, Vinicius; Zen Karam, Leandro; Rocha Pitta, Christiano S.; Ribeiro, Richardson; Simioni Assmann, Tangriani; Cardozo da Silva, Jean Carlos; Bertotti, Fábio L.; Kalinowski, Hypolito J.; Cardoso, Rafael

    2015-09-01

    This paper reports the process of pattern classification of the chewing process of ruminants. We propose a simplified signal processing scheme for optical fiber Bragg grating (FBG) sensors based on machine learning techniques. The FBG sensors measure the biomechanical forces during jaw movements and an artificial neural network is responsible for the classification of the associated chewing pattern. In this study, three patterns associated to dietary supplement, hay and ryegrass were considered. Additionally, two other important events for ingestive behavior studies were monitored, rumination and idle period. Experimental results show that the proposed approach for pattern classification has been capable of differentiating the materials involved in the chewing process with a small classification error.

  12. Surface deformation monitoring and reconstruction of honeycomb structure based on FBG sensors

    NASA Astrophysics Data System (ADS)

    Liu, Shulin; Lu, Jiyun; Zheng, Zhaoyu

    2015-07-01

    Honeycomb structure with high stiffness and light weight is expected to be more applied in the field of morphing wing. We propose a surface reconstruction algorithm based on FBG sensors to reconstruct the surface deformation of honeycomb structure real-timely and rapidly. When flexible honeycomb cores are driven by SMA actuators, the surface curvature monitored by FBG sensing array can be inferred from the changes of central wavelength. According to the surface reconstruction algorithm we proposed, the surface shape can be reconstructed. Composite single-row honeycomb structure specimen consisting of 8 cores, whose cell walls length and thickness is 8mm and 2mm respectively, is bended by electrified SMA actuators into the new steady shape. The experiment shows that the reconstructed surface shape has great agreement with the visual recording surface shape and the error is 5.76% on average.

  13. Dynamic optical arbitrary waveform shaping based on cascaded optical modulators of single FBG.

    PubMed

    Chen, Jingyuan; Li, Peili

    2015-08-10

    A dynamic optical arbitrary waveform generation (O-AWG) with amplitude and phase independently controlled in optical modulators of single fiber Bragg Grating (FBG) has been proposed. This novel scheme consists of several optical modulators. In the optical modulator (O-MOD), a uniform FBG is used to filter spectral component of the input signal. The amplitude is controlled by fiber stretcher (FS) in Mach-Zehnder interference (MZI) structure through interference of two MZI arms. The phase is manipulated via the second FS in the optical modulator. This scheme is investigated by simulation. Consequently, optical pulse trains with different waveforms as well as pulse trains with nonuniform pulse intensity, pulse spacing and pulse width within each period are obtained through FSs adjustment to alter the phase shifts of signal in each O-MOD. PMID:26367920

  14. Design and development of a low power, low cost, portable fiber Bragg grating (FBG) sensor interrogation system

    NASA Astrophysics Data System (ADS)

    Cai, Zhaohui; Phua, Jiliang; Hao, Jianzhong; Dong, Bo; Wang, Xian; Meng, Yu Song; Chiam, Tat Meng

    2011-11-01

    In this paper, the design and development of a low power, low cost and portable FBG Interrogation System is presented. The FBG interrogator consists of a spectral analyzer module, a photo detection module, and an electronic processing module. By using volume holographic phase grating as the continuous dispersion spectral element, our interrogator can achieve a maximum scanning frequency as high as 5 KHz for a single channel with a total power requirement of 25 W.

  15. Design and development of a low power, low cost, portable fiber Bragg grating (FBG) sensor interrogation system

    NASA Astrophysics Data System (ADS)

    Cai, Zhaohui; Phua, Jiliang; Hao, Jianzhong; Dong, Bo; Wang, Xian; Meng, Yu Song; Chiam, Tat Meng

    2012-01-01

    In this paper, the design and development of a low power, low cost and portable FBG Interrogation System is presented. The FBG interrogator consists of a spectral analyzer module, a photo detection module, and an electronic processing module. By using volume holographic phase grating as the continuous dispersion spectral element, our interrogator can achieve a maximum scanning frequency as high as 5 KHz for a single channel with a total power requirement of 25 W.

  16. FBG feedback's effects on distributed Bragg reflector fiber laser's polarization modes' beat

    NASA Astrophysics Data System (ADS)

    Li, Yunbo; Yu, Kuanglu; Lao, Yiqin; Cheng, Linghao; Wu, Chongqing; Zhao, Yao; Shang, Chao

    2015-09-01

    Distributed Bragg reflector (DBR) fiber optic laser has recently been extensively explored as a powerful sensor for various measurands, thanks to its high sensitivity, excellent signal-to-noise ratio, and inherent electronic magnetic immunity. The phase noise and linewidth of the laser's beat note limits this sensor's performances. We report in this letter, our recent experiments on noise reduction employing optical feedback from an external FBG. We also investigated the sensitivity reduction of the DBR sensor after feedback is introduced.

  17. Multi FBG femtosecond laser inscription in FPI based pressure sensors for temperature distribution

    NASA Astrophysics Data System (ADS)

    Poeggel, Sven; Duraibabu, Dinesbabu; Lacraz, Amedee; Kalli, Kyriacos; Tosi, Daniele; Leen, Gabriel; Lewis, Elfed

    2015-09-01

    We present in this paper an optical fiber pressure and temperature sensor (OFPTS) with multi Fibre Bragg Grating (FBG) array. The sensor based on an extrinsic Fabry Perot interferometer and is fabricated from silica glass. A femtosecond laser (FSL) was used to inscribe multiple FBGs proximately close to the diaphragm, parallel to each other. This concepts allows a chain of FBGs with miniature active length which can be a significant important tool for medical application, like radio frequency ablation (RFA) cancer treatment.

  18. A Magnetic Field Sensor Based on a Magnetic Fluid-Filled FP-FBG Structure.

    PubMed

    Xia, Ji; Wang, Fuyin; Luo, Hong; Wang, Qi; Xiong, Shuidong

    2016-04-29

    Based on the characteristic magnetic-controlled refractive index property, in this paper, a magnetic fluid is used as a sensitive medium to detect the magnetic field in the fiber optic Fabry-Perot (FP) cavity. The temperature compensation in fiber Fabry-Perot magnetic sensor is demonstrated and achieved. The refractive index of the magnetic fluid varies with the applied magnetic field and external temperature, and a cross-sensitivity effect of the temperature and magnetic field occurs in the Fabry-Perot magnetic sensor and the accuracy of magnetic field measurements is affected by the thermal effect. In order to overcome this problem, we propose a modified sensor structure. With a fiber Bragg grating (FBG) written in the insert fiber end of the Fabry-Perot cavity, the FBG acts as a temperature compensation unit for the magnetic field measurement and it provides an effective solution to the cross-sensitivity effect. The experimental results show that the sensitivity of magnetic field detection improves from 0.23 nm/mT to 0.53 nm/mT, and the magnetic field measurement resolution finally reaches 37.7 T. The temperature-compensated FP-FBG magnetic sensor has obvious advantages of small volume and high sensitivity, and it has a good prospect in applications in the power industry and national defense technology areas.

  19. In vivo experiments of laser thermotherapy on liver tissue with FBG temperature distribution sensor

    NASA Astrophysics Data System (ADS)

    Chen, Na; Chen, Shaofeng; Zhu, Hongfei; Liu, Shupeng; Chen, Zhenyi; Pang, Fufei; Wang, Tingyun

    2012-06-01

    In this paper, we report an in vivo experimental study of liver tissue during Laser Induced Interstitial Thermotherapy (LITT). Single FBG was used in the experiments to measure the temperature distribution profile of the bio tissue in real time. Ideally, the goal of LITT is to kill pathological tissue thoroughly and minimize its damage to surrounding healthy tissue, especially vital organs. The extent of treated tissue damage in the therapy is mainly dependent on the irradiation time and the laser power density at the tissue surface. Therefore, monitoring the dynamic change of the exact temperature distribution of the tissue is a key point for the safety of this treatment. In our experiments, FBG was embedded in the laser irradiated bio tissues and used as fully distributed temperature sensor. During the therapy, its reflection spectra were recorded and transmitted to PC in real time. The temperature profile along the FBG axial was reconstructed from its reflection spectrum by the spectra inversion program running on the PC. We studied the dependence of the temperature distribution and the laser output power experimentally and compared the results of in vivo and in vitro under similar laser irradiating conditions. Experimental results demonstrate the effectiveness of this method. Due to influence of body temperature, the in vivo measured temperature is higher than the in vitro one with an almost constant temperature difference value, but the slope and trend of the measured temperature curves in vivo and in vitro are almost identical.

  20. A Magnetic Field Sensor Based on a Magnetic Fluid-Filled FP-FBG Structure

    PubMed Central

    Xia, Ji; Wang, Fuyin; Luo, Hong; Wang, Qi; Xiong, Shuidong

    2016-01-01

    Based on the characteristic magnetic-controlled refractive index property, in this paper, a magnetic fluid is used as a sensitive medium to detect the magnetic field in the fiber optic Fabry-Perot (FP) cavity. The temperature compensation in fiber Fabry-Perot magnetic sensor is demonstrated and achieved. The refractive index of the magnetic fluid varies with the applied magnetic field and external temperature, and a cross-sensitivity effect of the temperature and magnetic field occurs in the Fabry-Perot magnetic sensor and the accuracy of magnetic field measurements is affected by the thermal effect. In order to overcome this problem, we propose a modified sensor structure. With a fiber Bragg grating (FBG) written in the insert fiber end of the Fabry-Perot cavity, the FBG acts as a temperature compensation unit for the magnetic field measurement and it provides an effective solution to the cross-sensitivity effect. The experimental results show that the sensitivity of magnetic field detection improves from 0.23 nm/mT to 0.53 nm/mT, and the magnetic field measurement resolution finally reaches 37.7 T. The temperature-compensated FP-FBG magnetic sensor has obvious advantages of small volume and high sensitivity, and it has a good prospect in applications in the power industry and national defense technology areas. PMID:27136564

  1. Simultaneous measurement of magnetic field and temperature based on an etched TCFMI cascaded with an FBG

    NASA Astrophysics Data System (ADS)

    Yan, Guofeng; Zhang, Liang; He, Sailing

    2016-04-01

    In this paper, a dual-parameter measurement scheme based on an etched thin core fiber modal interferometer (TCMI) cascaded with a fiber Bragg grating (FBG) is proposed and experimentally demonstrated for simultaneous measurement of magnetic field and temperature. The magnetic field and temperature responses of the packaged TCFMI were first investigated, which showed that the magnetic field sensitivity could be highly enhanced by decreasing of the TCF diameter and the temperature-cross sensitivities were up to 3-7 Oe/°C at 1550 nm. Then, the theoretical analysis and experimental demonstration of the proposed dual-parameter sensing scheme were conducted. Experimental results show that, the reflection of the FBG has a magnetic field intensity and temperature sensitivities of -0.017 dB/Oe and 0.133 dB/°C, respectively, while the Bragg wavelength of the FBG is insensitive to magnetic field and has a temperature sensitivity of 13.23 pm/°C. Thus by using the sensing matrix method, the intensity of the magnetic field and the temperature variance can be measured, which enables magnetic field sensing under strict temperature environments. In the on-off time response test, the fabricated sensor exhibited high repeatability and short response time of ∼19.4 s. Meanwhile the reflective sensing probe type is more compact and practical for applications in hard-to-reach conditions.

  2. A Magnetic Field Sensor Based on a Magnetic Fluid-Filled FP-FBG Structure.

    PubMed

    Xia, Ji; Wang, Fuyin; Luo, Hong; Wang, Qi; Xiong, Shuidong

    2016-01-01

    Based on the characteristic magnetic-controlled refractive index property, in this paper, a magnetic fluid is used as a sensitive medium to detect the magnetic field in the fiber optic Fabry-Perot (FP) cavity. The temperature compensation in fiber Fabry-Perot magnetic sensor is demonstrated and achieved. The refractive index of the magnetic fluid varies with the applied magnetic field and external temperature, and a cross-sensitivity effect of the temperature and magnetic field occurs in the Fabry-Perot magnetic sensor and the accuracy of magnetic field measurements is affected by the thermal effect. In order to overcome this problem, we propose a modified sensor structure. With a fiber Bragg grating (FBG) written in the insert fiber end of the Fabry-Perot cavity, the FBG acts as a temperature compensation unit for the magnetic field measurement and it provides an effective solution to the cross-sensitivity effect. The experimental results show that the sensitivity of magnetic field detection improves from 0.23 nm/mT to 0.53 nm/mT, and the magnetic field measurement resolution finally reaches 37.7 T. The temperature-compensated FP-FBG magnetic sensor has obvious advantages of small volume and high sensitivity, and it has a good prospect in applications in the power industry and national defense technology areas. PMID:27136564

  3. Design and optimization of power current transformer based on FBG sensing

    NASA Astrophysics Data System (ADS)

    Ren, N. K.; Xiong, Y. L.; Liang, H.; Meng, S.; Wu, M. Z.

    2015-10-01

    A new kind of power frequency current mutual inductance device based on the optical fiber measurement technology was proposed in this paper. The new device was made up of excitation current source, sensing system and magnetic circuit. The bus-bar was selected as excitation current source. The giant magnetostrictive material and fiber Bragg Grating (GMM-FBG) were combined as the sensing system. The magnetic circuit was consisting of the magnetic materials and permanent magnet materials. The numerical analysis of the magnetic field which generated in the sensors was achieved through the finite element analysis. In the simulation, the quiescent operating point of GMM-FBG sensor was confirmed; the size of the material in the magnetic circuit system was optimized to ensure the good output performance of sensing system. Finally, the numerical relationship between excitation current and the internal magnetic field of the Terfenol-D rods was established. Meanwhile, the calibration of sensor was achieved through the experiment system of the GMM-FBG current transformer sensor.

  4. Measurement of Psychiatric Treatment Adherence

    PubMed Central

    Sajatovic, Martha; Velligan, Dawn; Weiden, Peter J.; Valenstein, Marcia; Ogedegbe, Gbenga

    2014-01-01

    Objective Nonadherence to medications for mental disorders substantially limits treatment effectiveness and results in higher rates of relapse, hospitalization, and disability. Accurate measurement of medication adherence is important not only in adherence research, but also in clinical trials in which medications are being evaluated, and in clinical practice where failure to detect nonadherence results in premature medication changes, unnecessary polypharmacy, and greater likelihoods of functional deteriorations and hospitalizations. This is a review of psychiatric treatment adherence methods and measures arising from a meeting on “Methodological Challenges in Psychiatric Treatment Adherence Research” held on September 27-28, 2007 in Bethesda, MD and organized by the National Institute of Mental Health (NIMH). Methods This paper reviews the range of modalities currently available for assessing adherence behavior including pill counts, pharmacy records, technology-assisted monitoring, biological assays, and a range of self-report and interviewer-rated scales. Measures of adherence attitudes are also reviewed. Results Each of the adherence measures described are imperfect estimates of actual medication ingestion but each provides informative estimates of adherence or the attitudinal factors associated with adherence. Measure selection depends on a range of factors including the patient sample, the context in which the measure is being used, and the clinical outcomes expected from various levels of nonadherence. The use of multiple measures of adherence is encouraged to balance the limitations of individual measures. Conclusion While adherence assessment has become increasingly sophisticated in recent years there remains a need for refinement and expansion on currently available methods and measures. PMID:21109048

  5. Pharmacists’ perspectives on promoting medication adherence among patients with HIV

    PubMed Central

    Kibicho, Jennifer W.; Owczarzak, Jill

    2015-01-01

    Objectives To provide pharmacists’ perspectives on medication adherence barriers for patients with human immunodeficiency virus (HIV) and to describe pharmacists’ strategies for promoting adherence to antiretroviral medications. Design Multisite, qualitative, descriptive study. Setting Four midwestern U.S. states, from August through October 2009. Participants 19 pharmacists at 10 pharmacies providing services to patients with HIV. Intervention Pharmacists were interviewed using a semistructured interview guide. Main outcome measures Barriers to medication adherence, pharmacist interventions, challenges to promoting adherence. Results Pharmacists reported a range of adherence barriers that were patient specific (e.g., cognitive factors, lack of social support), therapy related (e.g., adverse effects, intolerable medications), and structural level (e.g., strained provider relationships). They used a combination of individually tailored, patient-specific interventions that identified and resolved adherence barriers and actively anticipated and addressed potential adherence barriers. Pharmacist interventions included medication-specific education to enhance patient self-efficacy, follow-up calls to monitor adherence, practical and social support to motivate adherence, and patient referrals to other health care providers. However, the pharmacists faced internal (e.g., lack of time, lack of trained personnel) and external (e.g., insurance policies that disallowed patient enrollment in automatic prescription refill program) challenges. Conclusion Pharmacists in community settings went beyond prescription drug counseling mandated by law to provide additional pharmacy services that were tailored to the needs of patients with HIV. Given that many individuals with HIV are living longer, more research is needed on the effectiveness and cost effectiveness of pharmacists’ interventions in clinical practice, in order to inform insurance reimbursement policies. PMID

  6. Biologic Influences on Exercise Adherence.

    ERIC Educational Resources Information Center

    Dishman, Rod K.

    1981-01-01

    Diagnostic profiles of 362 male participants in an exercise program were analyzed to determine the biological variables between exercise adherence and symptoms of coronary disease. Findings indicated that individuals with lower metabolic capacity tended to adhere longer, to be less fit, were leaner, and began with more symptoms related to coronary…

  7. Aircraft health and usage monitoring system for in-flight strain measurement of a wing structure

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Hyuk; Park, Yurim; Kim, Yoon-Young; Shrestha, Pratik; Kim, Chun-Gon

    2015-10-01

    This paper presents an aircraft health and usage monitoring system (HUMS) using fiber Bragg grating (FBG) sensors. This study aims to implement and evaluate the HUMS for in-flight strain monitoring of aircraft structures. An optical-fiber-based HUMS was developed and applied to an ultralight aircraft that has a rectangular wing shape with a strut-braced configuration. FBG sensor arrays were embedded into the wing structure during the manufacturing process for effective sensor implementation. Ground and flight tests were conducted to verify the integrity and availability of the installed FBG sensors and HUMS devices. A total of 74 flight tests were conducted using the HUMS implemented testbed aircraft, considering various maneuvers and abnormal conditions. The flight test results revealed that the FBG-based HUMS was successfully implemented on the testbed aircraft and operated normally under the actual flight test environments as well as providing reliable in-flight strain data from the FBG sensors over a long period of time.

  8. Discretely tunable Tm-doped fiber-based MOPA using FBG arrays as spectral filters

    NASA Astrophysics Data System (ADS)

    Tiess, T.; Junaid, S.; Becker, M.; Rothhardt, M.; Bartelt, H.; Jäger, M.

    2016-03-01

    Over the past years, Thulium (Tm) -doped fiber lasers in the 2μm region have gained a lot of interest due to many potential applications in materials processing and biophotonics. Based on the broad gain regions spanning from 1800nm to 2100nm, they offer the perfect basis to implement broadly tunable and user-friendly light sources like they are increasingly demanded in spectroscopic applications. Recently, a novel tuning mechanism based on a fiber Bragg grating (FBG) array as versatile spectral filter has been reported. This concept combines unique spectral freedom for customized tuning ranges and ultrabroad bandwidths with a fiber-integrated setup in order to maintain the advantages of the waveguide geometry. In this work, we demonstrate such a dispersion tuned and pulsed fiber laser in the Tm domain around 1950nm using a modulator and a discrete FBG array to control the emission wavelength. In order to comply with the demands of potential applications in biophotonics, for the first time, this tuning concept is realized in a polarization maintaining (PM) configuration ensuring linearly polarized output. While a simple FBG array is employed containing five gratings inscribed in PM fiber, we also outline the prospect to implement FBGs fabricated in a standard single mode fiber. The emission characteristics of the system are investigated showing pulse durations down to 11ns and a good spectral signal contrast. In order to highlight the prospect for tunable high-power operation, we have also implemented an amplification stage scaling the average power to more than 25W.

  9. Integrated microfluidic flowmeter based on a micro-FBG inscribed in Co²⁺-doped optical fiber.

    PubMed

    Liu, Zhengyong; Tse, Ming-Leung Vincent; Zhang, A Ping; Tam, Hwa-Yaw

    2014-10-15

    A novel microfluidic flowmeter integrated with microfiber Bragg grating (µFBG) is presented. Two glass capillaries and a short length of high-light-absorption Co²⁺-doped optical fiber were stacked inside a larger outer capillary tube. The stack was then drawn into a tapered device. Two microchannels with the diameter of ~50  μm were formed inside the capillaries for flowing of microfluidics. An FBG was inscribed in the tapered Co²⁺-doped fiber with waist diameter of ~70  μm, and acts as a flow-rate sensor. A pump laser with wavelength of 1480 nm was utilized to locally heat the µFBG, rendering the µFBG as miniature "hot-wire" flowmeter. The flow rate of the liquid in the microchannels is determined by the induced wavelength shift of the µFBG. The experimental results achieve a minimum detectable change of ~16  nL/s in flow rate, which is very promising in the use as part of biochips.

  10. Optical sensor based on hybrid FBG/titanium dioxide coated LPFG for monitoring organic solvents in edible oils.

    PubMed

    Coelho, Luís; Viegas, Diana; Santos, José Luís; de Almeida, José Manuel Marques Martins

    2016-01-01

    A hybrid optical sensing scheme based on a fiber Bragg grating (FBG) combined with a titanium dioxide coated long period fiber grating (LPFG) for monitoring organic solvents in high refractive index edible oils is reported. In order to investigate and optimize the sensor performance, two different FBG/LPFG interrogation systems were investigated. The readout of the sensor was implemented using either the wavelength shift of the LPFG resonance dip or the variation in the optical power level of the reflected/transmitted light at the FBG wavelength peak, which in turn depends on the wavelength position of the LPFG resonance. Hexane concentrations up to 20%V/V, corresponding to the refractive index range from 1.451 to 1.467, were considered. For the transmission mode of operation, sensitivities of 1.41 nm/%V/V and 0.11 dB/%V/V, with resolutions of 0.58%V/V and 0.29%V/V, were achieved when using the LPFG wavelength shift and the FBG transmitted optical power, respectively. For the FBG reflection mode of operation, a sensitivity of 0.07 dB/%V/V and a resolution better than 0.16%V/V were estimated.

  11. Optical sensor based on hybrid FBG/titanium dioxide coated LPFG for monitoring organic solvents in edible oils.

    PubMed

    Coelho, Luís; Viegas, Diana; Santos, José Luís; de Almeida, José Manuel Marques Martins

    2016-02-01

    A hybrid optical sensing scheme based on a fiber Bragg grating (FBG) combined with a titanium dioxide coated long period fiber grating (LPFG) for monitoring organic solvents in high refractive index edible oils is reported. In order to investigate and optimize the sensor performance, two different FBG/LPFG interrogation systems were investigated. The readout of the sensor was implemented using either the wavelength shift of the LPFG resonance dip or the variation in the optical power level of the reflected/transmitted light at the FBG wavelength peak, which in turn depends on the wavelength position of the LPFG resonance. Hexane concentrations up to 20%V/V, corresponding to the refractive index range from 1.451 to 1.467, were considered. For the transmission mode of operation, sensitivities of 1.41 nm/%V/V and 0.11 dB/%V/V, with resolutions of 0.58%V/V and 0.29%V/V, were achieved when using the LPFG wavelength shift and the FBG transmitted optical power, respectively. For the FBG reflection mode of operation, a sensitivity of 0.07 dB/%V/V and a resolution better than 0.16%V/V were estimated. PMID:26653438

  12. Bacterial infection of wounds: fibronectin-mediated adherence group A and C streptococci to fibrin thrombi in vitro.

    PubMed

    Chhatwal, G S; Valentin-Weigand, P; Timmis, K N

    1990-09-01

    Adherence of group A, B, and C streptococci to fibrin thrombi was studied by using a novel fluorochrome microassay carried out in microdilution plates in which fibrin thrombi had been prepared by clotting citrated human, cattle, or horse plasma. Substantial adherence was observed with various strains of group A and C streptococci, whereas little was observed with group B streptococci. Adherence of all group A and C streptococcal strains decreased by up to 40% when fibronectin was depleted from the plasmas used for preparing fibrin thrombi, and fibronectin repletion increased adherence of streptococci in a dose-dependent manner. Addition of the 210-kilodalton C-terminal fragment of fibronectin to fibronectin-depleted plasma restored the adherence of group C but not group A streptococci, whereas addition of the 29-kilodalton N-terminal fragment was without any effect for all tested streptococcal strains. Prior incubation of group A and C streptococcal strains with fibronectin markedly increased their adherence, but treatment with proteases abolished their ability to adhere to fibrin thrombi. Adherence of group B streptococci was not affected by either fibronectin depletion or proteolytic digestion. These results indicate that both fibronectin incorporated into the fibrin matrix of thrombi and soluble fibronectin can mediate adherence of group A and C streptococci to fibrin thrombi and that binding sites for fibronectin located on the bacterial surface mediate this adherence.

  13. Adherence of oral streptococci to an immobilized antimicrobial agent.

    PubMed

    Saito, T; Takatsuka, T; Kato, T; Ishihara, K; Okuda, K

    1997-08-01

    An antimicrobial agent, 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride, was immobilized on silica. Interaction between the material (termed) OAIS) and various oral bacterial species were then studied. Seven species of Streptococcus and two Actinomyces were investigated for their ability to adhere to this biomaterial. Cell-surface hydrophobicity and zeta-potential were examined as well. Analysis of extracted hydrophobic proteins which adhered to OAIS revealed that the adherence of these micro-organisms was closely related to the hydrophobicity of their cell surfaces. The results of zeta-potential assays indicated that negative charge on the cell surface inhibited adherence to OAIS. Gel electrophoresis revealed that OAIS could absorb cell-surface hydrophobic proteins from all bacterial species tested. Preadsorption of hydrophobic components on the cell surface inhibited adherence of the Strep. mutans strain to OAIS in a dose-dependent manner. The results indicate that OAIS adsorption of these oral bacteria was dependent on the degree of hydrophobicity of their surfaces. A major component of this adherence was hydrophobic cell-surface proteins. PMID:9347116

  14. Packaging and testing of fiber Bragg gratings for use as strain sensor in rock specimens

    NASA Astrophysics Data System (ADS)

    Castro-Caicedo, Alvaro; Torres, Pedro; Lain, Ricardo

    2013-11-01

    This paper reports a packaging and calibration procedure for surface mounting of fiber Bragg grating (FBG) sensors to measure strain in rocks. The packaging of FBG sensors is performed with glass fiber and polyester resin, and then subjected to tensile loads in order to obtain strength and deformability parameters, necessaries to assess the mechanical performance of the sensor packaging. For a specific package, an optimal curing condition has been found, showing good repeatability and adaptability for non-planar surfaces, such as occurs in rock engineering. The successfully packaged sensors and electrical strain gages were attached to standard rock specimens of gabbro. Longitudinal and transversal strains under compression loads were measured with both techniques, showing that response of FBG sensors is linear and reliable. An analytical model is used to characterize the influences of rock substrate and FBG packaging in strain transmission. As a result, we obtained a sensor packaging for non-planar and complex natural material under acceptable sensitivity suitable for very small strains as occurs in hard rocks.

  15. Fiber Bragg grating strain sensors to monitor and study active volcanoes

    NASA Astrophysics Data System (ADS)

    Sorrentino, Fiodor; Beverini, Nicolò; Carbone, Daniele; Carelli, Giorgio; Francesconi, Francesco; Gambino, Salvo; Giacomelli, Umberto; Grassi, Renzo; Maccioni, Enrico; Morganti, Mauro

    2016-04-01

    Stress and strain changes are among the best indicators of impending volcanic activity. In volcano geodesy, borehole volumetric strain-meters are mostly utilized. However, they are not easy to install and involve high implementation costs. Advancements in opto-electronics have allowed the development of low-cost sensors, reliable, rugged and compact, thus particularly suitable for field application. In the framework of the EC FP7 MED-SUV project, we have developed strain sensors based on the fiber Bragg grating (FBG) technology. In comparison with previous implementation of the FBG technology to study rock deformations, we have designed a system that is expected to offer a significantly higher resolution and accuracy in static measurements and a smooth dynamic response up to 100 Hz, implying the possibility to observe seismic waves. The system performances are tailored to suit the requirements of volcano monitoring, with special attention to power consumption and to the trade-off between performance and cost. Preliminary field campaigns were carried out on Mt. Etna (Italy) using a prototypal single-axis FBG strain sensor, to check the system performances in out-of-the-lab conditions and in the harsh volcanic environment (lack of mains electricity for power, strong diurnal temperature changes, strong wind, erosive ash, snow and ice during the winter time). We also designed and built a FBG strain sensor featuring a multi-axial configuration which was tested and calibrated in the laboratory. This instrument is suitable for borehole installation and will be tested on Etna soon.

  16. Heparin-mediated inhibition of Chlamydia psittaci adherence to HeLa cells.

    PubMed

    Gutiérrez-Martín, C B; Ojcius, D M; Hsia, R; Hellio, R; Bavoil, P M; Dautry-Varsat, A

    1997-01-01

    The adherence of human strains of Chlamydia trachomatis has been recently shown to be inhibitable by heparin and heparitinase, leading to the proposal that Chlamydia binding to host cells may be mediated by a glycosaminoglycan (GAG)-dependent mechanism. We here describe the adherence of the guinea-pig pathogen, Chlamydia psittaci GPIC, to HeLa cells, which was measured by cytofluorometry with chlamydiae whose DNA was fluorescently labelled. Adherence could be inhibited by heat or trypsin pretreatment of the bacteria, and binding was much faster at 37 degrees C (reaching a plateau within 1 h) than 4 degrees C. Little binding remained when host cells were pre-fixed with paraformaldehyde, suggesting that host cell receptor mobility may be required for effective adherence. Visualization by confocal microscopy confirmed that the bacteria were at or near the host cell surface during the entire time-course of these experiments. Adherence increased as a function of pH between pH 6 and pH 8.0-8.5. Both adherence and infection of HeLa cells could be inhibited with heparin when the adherence step was performed at 4 degrees C, but only infection was inhibited when the adherence step was performed at 37 degrees C, even though heparitinase could block adherence at either 4 degrees C or 37 degrees C. Even at 4 degrees C, heparin-mediated inhibition was significantly lower at pH 8 than pH 7.4, suggesting that GAG-independent mechanisms may play a role in the higher adherence observed at basic pH. These results therefore demonstrate that a GAG-dependent adherence step may be operative in C. psittaci, and raise the possibility that other adherence mechanisms may also contribute to binding by this chlamydial strain. Furthermore, they suggest that there may not be a strict correlation between C. psittaci adherence and the ability to cause productive infections.

  17. FIBER BRAGG GRATING SENSORS FOR LOCALIZED STRAIN MEASUREMENTS AT LOW TEMPERATURE AND IN HIGH MAGNETIC FIELD

    SciTech Connect

    Ramalingam, Rajinikumar

    2010-04-09

    Study of magnetostrictive effects in the bulk superconductors is very essential and can give more knowledge about the effects like namely, flux pinning induced strain, pincushion distortions in the magnets and so on. Currently used electro mechanical sensors are magnetic field dependent and can only give the global stress/strain information but not the local stress/strains. But the information like radius position dependent strain and characterisation of shape distortion in non cylindrical magnets are interesting. Wavelength encoded multiplexed fiber Bragg Grating sensors inscribed in one fiber gives the possibility to measure magentostrictive effects spatially resolved in low temperature and high magnetic field. This paper specifies the design and technology requirements to adapt FBG sensors for such an application. Also reports the experiments demonstrate the properties of glass FBG at low temperature (4.2 K) and the results of strain measurement at 4.2 K/8 T. The sensor exhibits a linear wavelength change for the strain change.

  18. The effectiveness of metal coating on FBG sensor sensitivity at cryogenic temperature

    NASA Astrophysics Data System (ADS)

    Lupi, C.; Felli, F.; Caponero, M. A.; Paolozzi, A.

    2007-07-01

    The very low thermal expansion coefficient of silica at cryogenic temperature prevents the use of Fibre Bragg Grating (FBG) sensors for high resolution temperature monitoring in cryogenic environments involving liquid gases or space applications. To overcome such limitations sensors have been coated with different metals to improve the measurement sensitivity in the very low temperature region, i.e. 4.2-35 K. Various coatings have been deposited by electrowinning on the external fibre surface after aluminium pre-coating. Full characterization of this new type of sensor is described in the paper.

  19. Development and field trial of a FBG-based magnetic sensor for large hydrogenerators

    NASA Astrophysics Data System (ADS)

    Fracarolli, João. P. V.; Rosolem, João. B.; Tomiyama, Elias K.; Floridia, Claudio; Penze, Rivael S.; Peres, Rodrigo; Dini, Danilo C.; Hortencio, Claudio A.; Dilli, Paulo I. G.; da Silva, Erlon V.; dos Santos, Marcéu. C.; Fruett, Fabiano

    2016-05-01

    We propose a passive optical sensor for online magnetic field monitoring in large hydrogenerators, based on FBG (Fiber Bragg Grating) technology and a magnestostrictive material (Terfenol-D). The objective of this sensor is to detect faults in the rotor windings due to inter turn short-circuits. This device is packaged in a novel rod-shaped enclosure, allowing it to be easily installed on the ventilation ducts of the stator of the machine. This sensor was developed and tested in laboratory and it has been evaluated in a field test on a 200 MVA, 60 poles hydrogenerator.

  20. The magnitude of a human bite measured exactly at the molar Intercuspidation using FBG

    NASA Astrophysics Data System (ADS)

    Marin, Gabriela Costa; Milczewski, Maura S.; Abe, Ilda; Lopes, Stephani C. P. S.; Camargo, Elisa S.; Kalinowski, Hypolito J.

    2014-05-01

    The aim of the study is to develop a new punctual method to determine the human bite force, between uppers and lowers first molars, at the moment of occlusion in maximum intercuspation. Fibre optic Bragg gratings are encapsulated in an acetate splint made by casting of a volunteer lower dentition. Splint sensor was positioned into the mouth to be pressured with minimal occlusal interference. The transversal pressure on the FBG was acquired at the moment of before occlusion (free), occlusion and biting. The measured forces were 12N during occlusion and 28N bite force, between right uppers and lowers first molars.

  1. Linear FBG interrogation with a wavelength-swept fiber laser and a volume phase grating spectrometer

    NASA Astrophysics Data System (ADS)

    Kim, Hyunjin; Song, Minho

    2011-05-01

    We propose a novel FBG (fiber Bragg grating) sensor system that uses a tunable wavelength laser and a volume phase grating spectrometer. The effect of nonlinear wavelength scanning and uneven power profile of the fiber laser, which substantially degrades the measurement accuracy, is minimized by using a spectrometer demodulation. The constructed sensor system showed linear output according to the Bragg wavelength variation, and showed much higher signal-to-noise ratio compared to the conventional spectrometer demodulation which used much dimmer broadband light sources.

  2. Linearized interrogation of FDML FBG sensor system using PMF Sagnac interferometer

    NASA Astrophysics Data System (ADS)

    Lee, Hwi Don; Jung, Eun Joo; Jeong, Myung Yung; Kim, Chang-Seok

    2009-10-01

    A novel linearized interrogation method is presented for Fourier-domain mode locked (FDML) fiber Bragg grating (FBG) sensor system. In the ultra high-speed regime over 10 kHz modulation, only sine wave is available to scan a center wavelength of FDML wavelength-swept laser instead of conventional triangular wave. However, sine wave modulation has been suffered an exaggerated nonlinear filter response in demodulating the time-encoded parameter into the absolute wavelength. The linearized demodulation is demonstrated by the third order polynomial conversion of filter between the time-encoded parameter and wavelength-encoded parameter based on the spectral information of polarization maintaining fiber (PMF) Sagnac interferometer.

  3. Hybrid Optoelectronic Bistability in Frequency-Domain and Its Potential Application in FBG Sensors

    NASA Astrophysics Data System (ADS)

    Ye, Hong-An; Liu, Chun-Yu; Lv, Guo-Hui; Xin, Hai-Ying; Zhu, Xiao-Liang

    2008-12-01

    We propose a novel optical bistable device (OBD) in frequency-domain with which we can perform optical bistable operations in a number of fibre Bragg gratings (FBGs) which are included in the same OBD. Such an OBD may bring more opportunities in applications and, as an example, we show the possibility of using it in an FBG sensor demodulating system. By use of a tunable light source, consisting of a broad band source and a scanning fibre F-P (FFP), we demonstrate the above-mentioned operations experimentally.

  4. Decreased Adherence of Enterohemorrhagic Escherichia coli to HEp-2 Cells in the Presence of Antibodies That Recognize the C-Terminal Region of Intimin

    PubMed Central

    Gansheroff, Lisa J.; Wachtel, Marian R.; O'Brien, Alison D.

    1999-01-01

    Antiserum raised against intimin from enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain 86-24 has been shown previously by our laboratory to inhibit adherence of this strain to HEp-2 cells. In the present study, we sought to identify the region(s) of intimin important for the effect of anti-intimin antisera on EHEC adherence and to determine whether antisera raised against intimin from an O157:H7 strain could reduce adherence of other strains. Compared to preimmune serum controls, polyclonal sera raised against the histidine-tagged intimin protein RIHisEae (intiminO157) or against His-tagged C-terminal fragments of intimin from strain 86-24 reduced adherence of this strain. Furthermore, an antibody fraction purified from the anti-RIHisEae serum that contained antibodies to the C-terminal third of intimin, the putative receptor-binding domain, also reduced adherence of strain 86-24, but a purified fraction containing antibodies to the N-terminal two-thirds of intimin did not inhibit adherence. The polyclonal anti-intiminO157 serum raised against RIHisEae inhibited, to different degrees, the adherence of another O157:H7 strain, an EHEC O55:H7 strain, one of two independent EHEC O111:NM isolates tested, and one of two EHEC O26:H11 strains tested. Adherence of the other O26:H11 and O111:NM strains and an EPEC O127:H6 strain was not reduced. Finally, immunoblot analysis indicated a correlation between the antigenic divergence in the C-terminal third of intimins from different strains and the capacity of anti-intiminO157 antiserum to reduce adherence of heterologous strains. Taken together, these data suggest that intiminO157 could be used as an immunogen to elicit adherence-blocking antibodies against O157:H7 strains and closely-related EHEC. PMID:10569757

  5. Medication Adherence Measures: An Overview.

    PubMed

    Lam, Wai Yin; Fresco, Paula

    2015-01-01

    WHO reported that adherence among patients with chronic diseases averages only 50% in developed countries. This is recognized as a significant public health issue, since medication nonadherence leads to poor health outcomes and increased healthcare costs. Improving medication adherence is, therefore, crucial and revealed on many studies, suggesting interventions can improve medication adherence. One significant aspect of the strategies to improve medication adherence is to understand its magnitude. However, there is a lack of general guidance for researchers and healthcare professionals to choose the appropriate tools that can explore the extent of medication adherence and the reasons behind this problem in order to orchestrate subsequent interventions. This paper reviews both subjective and objective medication adherence measures, including direct measures, those involving secondary database analysis, electronic medication packaging (EMP) devices, pill count, and clinician assessments and self-report. Subjective measures generally provide explanations for patient's nonadherence whereas objective measures contribute to a more precise record of patient's medication-taking behavior. While choosing a suitable approach, researchers and healthcare professionals should balance the reliability and practicality, especially cost effectiveness, for their purpose. Meanwhile, because a perfect measure does not exist, a multimeasure approach seems to be the best solution currently.

  6. Medication Adherence Measures: An Overview

    PubMed Central

    Lam, Wai Yin; Fresco, Paula

    2015-01-01

    WHO reported that adherence among patients with chronic diseases averages only 50% in developed countries. This is recognized as a significant public health issue, since medication nonadherence leads to poor health outcomes and increased healthcare costs. Improving medication adherence is, therefore, crucial and revealed on many studies, suggesting interventions can improve medication adherence. One significant aspect of the strategies to improve medication adherence is to understand its magnitude. However, there is a lack of general guidance for researchers and healthcare professionals to choose the appropriate tools that can explore the extent of medication adherence and the reasons behind this problem in order to orchestrate subsequent interventions. This paper reviews both subjective and objective medication adherence measures, including direct measures, those involving secondary database analysis, electronic medication packaging (EMP) devices, pill count, and clinician assessments and self-report. Subjective measures generally provide explanations for patient's nonadherence whereas objective measures contribute to a more precise record of patient's medication-taking behavior. While choosing a suitable approach, researchers and healthcare professionals should balance the reliability and practicality, especially cost effectiveness, for their purpose. Meanwhile, because a perfect measure does not exist, a multimeasure approach seems to be the best solution currently. PMID:26539470

  7. Medication Adherence Measures: An Overview.

    PubMed

    Lam, Wai Yin; Fresco, Paula

    2015-01-01

    WHO reported that adherence among patients with chronic diseases averages only 50% in developed countries. This is recognized as a significant public health issue, since medication nonadherence leads to poor health outcomes and increased healthcare costs. Improving medication adherence is, therefore, crucial and revealed on many studies, suggesting interventions can improve medication adherence. One significant aspect of the strategies to improve medication adherence is to understand its magnitude. However, there is a lack of general guidance for researchers and healthcare professionals to choose the appropriate tools that can explore the extent of medication adherence and the reasons behind this problem in order to orchestrate subsequent interventions. This paper reviews both subjective and objective medication adherence measures, including direct measures, those involving secondary database analysis, electronic medication packaging (EMP) devices, pill count, and clinician assessments and self-report. Subjective measures generally provide explanations for patient's nonadherence whereas objective measures contribute to a more precise record of patient's medication-taking behavior. While choosing a suitable approach, researchers and healthcare professionals should balance the reliability and practicality, especially cost effectiveness, for their purpose. Meanwhile, because a perfect measure does not exist, a multimeasure approach seems to be the best solution currently. PMID:26539470

  8. Packaged FBG sensors for real-time stress monitoring on deep-water riser

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Yang, Dexing; Jiang, Yajun; Wang, Meirong; Zhai, Huailun; Bai, Yang

    2014-11-01

    The safety of under-water risers in drilling platform is of great significance. A packaged fiber Bragg grating (FBG) sensor for real-time stress monitoring is designed for the applications on oil drilling risers under 3000 meters deep water. A copper tube which is the main component of the sensor has a small hole along its axes and a groove at its each end. The bare FBG is passed through the small hole and fixed to its ends by epoxy resin. Then the copper tube is packaged by filling the groove with structural adhesive. In order to avoid that the outer water-pressure is applied on the epoxy resin through the structural adhesive, a gap between the two types of glues is left. The relationships between the stress of the riser and the tension, pressure, temperature of the single sensor are discussed, respectively. The measured tension sensitivity is 136.75 pm/KN while the minimum R-square value is 0.99997. The experimental results also show that there is a good linear response between water-pressure and the Bragg wavelength from 0 to 30MPa, and the sensor can even survive under the pressure more than 30MPa. In addition, the Bragg wavelength shifts linearly with the increasing temperature from 0 to 40°C. So, the pressure and temperature can be easily compensated if another sensor without tension is used.

  9. Development of highly reliable advanced grid structure (HRAGS) demonstrator using FBG sensors

    NASA Astrophysics Data System (ADS)

    Takeya, H.; Sekine, K.; Kume, M.; Ozaki, T.; Takeda, N.; Tajima, N.

    2008-03-01

    There is a growing demand in recent years for lightweight structures in aircraft systems from the viewpoints of energy and cost savings. The authors have continued development of the Highly Reliable Advanced Grid Structure (HRAGS) for aircraft structure. HRAGS is provided with health monitoring functions that make use of Fiber Bragg Grating (FBG) sensors in advanced grid structures. To apply HRAGS technology to aircraft structures, a full-scale demonstrator visualizing the actual aircraft structure needs to be built and evaluated so that the effectiveness of the technology can be validated. So the authors selected the wing tip as the candidate structural member and proceeded to design and build a demonstrator. A box-structure was adopted as the structure for the wing-tip demonstrator, and HRAGS panels were used as the skin panels on the upper and lower surfaces of the structure. The demonstrator was designed using about 600 FBG sensors using a panel size of 1 x 2 m. By using the demonstrator, damage detection functions of HRAGS system were verified analytically. The results of the design and evaluation of the demonstrator are reported here.

  10. Effect of tubing material on conventional and thin FBG sensor for embedded environment impact monitoring of CFRP composites

    NASA Astrophysics Data System (ADS)

    Park, Yurim; Shrestha, Pratik; Kwon, Hyunseok; Kim, Jin-Hyuk; Kwon, Heejung; Kim, Chun-Gon

    2016-04-01

    Applications of composite materials in aerospace structures is increasing due to the outstanding properties, however, monitoring such composite structures exposed to harsh environments is still a posing issue. Low Earth orbit space structures are exposed to property degradation and damage from high-degree vacuum, ultraviolet radiation, thermal cycling, and atomic oxygen attack which are detrimental to composite materials. In this study, FBG sensors for embedding in CFRP composite plates in different thickness locations to provide health and damage monitoring of the material exposed to such environments regarding the overall health of the material with a focus on the exposed surface are explored in comparison to conventional FBG sensors.

  11. A Strain-Based Load Identification Model for Beams in Building Structures

    PubMed Central

    Hong, Kappyo; Lee, Jihoon; Choi, Se Woon; Kim, Yousok; Park, Hyo Seon

    2013-01-01

    A strain-based load identification model for beam structures subjected to multiple loads is presented. The number of sensors for the load identification model is the same as the number of load conditions acting on a beam structure. In the model, the contribution of each load to the strains measured by strain sensors is defined. In this paper, the longitudinal strains measured from multiplexed fiber Bragg grating (FBG) strain sensors are used in the load identification. To avoid the dependency on the selection of locations for FBG sensors installed on a beam structure, the measured strain is expressed by a general form of a strain sensing model defined by superimposing the distribution shapes for strains from multiple loads. Numerical simulation is conducted to verify the model. Then, the load identification model is applied to monitoring of applied loads on a 4 m-long steel beam subjected to two concentrated loads. In the experiment, seven FBG sensors and nine electrical strain gages (ESGs) were installed on the surface of the bottom flange. The experimental results indicate a good agreement between estimated loadings from the model and the loads applied by a hydraulic jack. PMID:23921825

  12. A strain-based load identification model for beams in building structures.

    PubMed

    Hong, Kappyo; Lee, Jihoon; Choi, Se Woon; Kim, Yousok; Park, Hyo Seon

    2013-08-05

    A strain-based load identification model for beam structures subjected to multiple loads is presented. The number of sensors for the load identification model is the same as the number of load conditions acting on a beam structure. In the model, the contribution of each load to the strains measured by strain sensors is defined. In this paper, the longitudinal strains measured from multiplexed fiber Bragg grating (FBG) strain sensors are used in the load identification. To avoid the dependency on the selection of locations for FBG sensors installed on a beam structure, the measured strain is expressed by a general form of a strain sensing model defined by superimposing the distribution shapes for strains from multiple loads. Numerical simulation is conducted to verify the model. Then, the load identification model is applied to monitoring of applied loads on a 4 m-long steel beam subjected to two concentrated loads. In the experiment, seven FBG sensors and nine electrical strain gages (ESGs) were installed on the surface of the bottom flange. The experimental results indicate a good agreement between estimated loadings from the model and the loads applied by a hydraulic jack.

  13. Enhanced adherence of methicillin-resistant Staphylococcus pseudintermedius sequence type 71 to canine and human corneocytes

    PubMed Central

    2014-01-01

    The recent worldwide spread of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in dogs is a reason for concern due to the typical multidrug resistance patterns displayed by some MRSP lineages such as sequence type (ST) 71. The objective of this study was to compare the in vitro adherence properties between MRSP and methicillin-susceptible (MSSP) strains. Four MRSP, including a human and a canine strain belonging to ST71 and two canine non-ST71 strains, and three genetically unrelated MSSP were tested on corneocytes collected from five dogs and six humans. All strains were fully characterized with respect to genetic background and cell wall-anchored protein (CWAP) gene content. Seventy-seven strain-corneocyte combinations were tested using both exponential- and stationary-phase cultures. Negative binomial regression analysis of counts of bacterial cells adhering to corneocytes revealed that adherence was significantly influenced by host and strain genotype regardless of bacterial growth phase. The two MRSP ST71 strains showed greater adherence than MRSP non-ST71 (p < 0.0001) and MSSP (p < 0.0001). This phenotypic trait was not associated to any specific CWAP gene. In general, S. pseudintermedius adherence to canine corneocytes was significantly higher compared to human corneocytes (p < 0.0001), but the MRSP ST71 strain of human origin adhered equally well to canine and human corneocytes, suggesting that MRSP ST71 may be able to adapt to human skin. The genetic basis of the enhanced in vitro adherence of ST71 needs to be elucidated as this phenotypic trait may be associated to the epidemiological success and zoonotic potential of this epidemic MRSP clone. PMID:24957656

  14. EX VIVO ADHERENCE TO MURINE ILEAL, BIOFILM FORMATION ABILITY AND PRESENCE OF ADHERENCE-ASSOCIATED OF HUMAN AND ANIMAL DIARRHEAGENIC ESCHERICHIA COLI.

    PubMed

    Sukkua, Kannika; Rattanachuay, Pattamarat; Sukhumungoon, Pharanai

    2016-01-01

    Diarrheagenic Escherichia coli (DEC) are important bacteria causing gastrointestinal infection, which can lead to severe forms of illnesses. This study focused on DEC adherent capabilities using murine intestinal tissue as a model. Ex vivo adherence results showed that enteroaggregative E. coli (EAEC) strain PSU280 exhibited the highest level of adherence, followed by strains from ETEC category. Scanning electron micrographs displayed tight binding and putative bacterial curli fibers, including putative fimbrial structures. The presence of putative curli fibers was confirmed by the presence of csgA, a curli major structural subunit gene. Five and 3 of 15 DEC possessed lpf (encoding long polar fimbriae) and agn43 (encoding antigen43), respectively. Comparable biofilm formation efficiency but variable levels autoaggregation were observed among the DEC strains. In addition, yeast agglutination could be visualized in 11/15 strains. This study demonstrates the adherent ability of DEC strains isolated in southern Thailand as well as a number of crucial adherence-associated genes, information of importance to the understanding of DEC pathogenesis in this region of the country. PMID:27086424

  15. Fiber Bragg Gratings, IT techniques and strain gauge validation for strain calculation on aged metal specimens.

    PubMed

    Montero, Ander; de Ocariz, Idurre Saez; Lopez, Ion; Venegas, Pablo; Gomez, Javier; Zubia, Joseba

    2011-01-01

    This paper studies the feasibility of calculating strains in aged F114 steel specimens with Fiber Bragg Grating (FBG) sensors and infrared thermography (IT) techniques. Two specimens have been conditioned under extreme temperature and relative humidity conditions making comparative tests of stress before and after aging using different adhesives. Moreover, a comparison has been made with IT techniques and conventional methods for calculating stresses in F114 steel. Implementation of Structural Health Monitoring techniques on real aircraft during their life cycle requires a study of the behaviour of FBG sensors and their wiring under real conditions, before using them for a long time. To simulate aging, specimens were stored in a climate chamber at 70 °C and 90% RH for 60 days. This study is framed within the Structural Health Monitoring (SHM) and Non Destructuve Evaluation (NDE) research lines, integrated into the avionics area maintained by the Aeronautical Technologies Centre (CTA) and the University of the Basque Country (UPV/EHU).

  16. MBM fuel feeding system design and evaluation for FBG pilot plant.

    PubMed

    Campbell, William A; Fonstad, Terry; Pugsley, Todd; Gerspacher, Regan

    2012-06-01

    A biomass fuel feeding system has been designed, constructed and evaluated for a fluidized bed gasifier (FBG) pilot plant at the University of Saskatchewan (Saskatoon, SK, Canada). The system was designed for meat and bone meal (MBM) to be injected into the gasifier at a mass flow-rate range of 1-5 g/s. The designed system consists of two stages of screw conveyors, including a metering stage which controlled the flow-rate of fuel, a rotary airlock and an injection conveyor stage, which delivered that fuel at a consistent rate to the FBG. The rotary airlock which was placed between these conveyors, proved unable to maintain a pressure seal, thus the entire conveying system was sealed and pressurized. A pneumatic injection nozzle was also fabricated, tested and fitted to the end of the injection conveyor for direct injection and dispersal into the fluidized bed. The 150 mm metering screw conveyor was shown to effectively control the mass output rate of the system, across a fuel output range of 1-25 g/s, while the addition of the 50mm injection screw conveyor reduced the irregularity (error) of the system output rate from 47% to 15%. Although material plugging was found to be an issue in the inlet hopper to the injection conveyor, the addition of air sparging ports and a system to pulse air into those ports was found to successfully eliminate this issue. The addition of the pneumatic injection nozzle reduced the output irregularity further to 13%, with an air supply of 50 slpm as the minimum air supply to drive this injector. After commissioning of this final system to the FBG reactor, the injection nozzle was found to plug with char however, and was subsequently removed from the system. Final operation of the reactor continues satisfactorily with the two screw conveyors operating at matching pressure with the fluidized bed, with the output rate of the system estimated based on system characteristic equations, and confirmed by static weight measurements made before

  17. Active mechanics and geometry of adherent cells and cell colonies

    NASA Astrophysics Data System (ADS)

    Banerjee, Shiladitya

    2014-03-01

    Measurements of traction stresses exerted by adherent cells or cell colonies on elastic substrates have yielded new insight on how the mechanical and geometrical properties of the substrate regulate cellular force distribution, mechanical energy, spreading, morphology or stress ber architecture. We have developed a generic mechanical model of adherent cells as an active contractile gel mechanically coupled to an elastic substrate and to neighboring cells in a tissue. The contractile gel model accurately predicts the distribution of cellular and traction stresses as observed in single cell experiments, and captures the dependence of cell shape, traction stresses and stress ber polarization on the substrate's mechanical and geometrical properties. The model further predicts that the total strain energy of an adherent cell is solely regulated by its spread area, in agreement with recent experiments on micropatterned substrates with controlled geometry. When used to describe the behavior of colonies of adherent epithelial cells, the model demonstrates the crucial role of the mechanical cross-talk between intercellular and extracellular adhesion in regulating traction force distribution. Strong intercellular mechanical coupling organizes traction forces to the colony periphery, whereas weaker intercellular coupling leads to the build up of traction stresses at intercellular junctions. Furthermore, in agreement with experiments on large cohesive keratinocyte colonies, the model predicts a linear scaling of traction forces with the colony size. This scaling suggests the emergence of an effective surface tension as a scale-free material property of the adherent tissue, originating from actomyosin contractility.

  18. Adherence and receptor relationships of Candida albicans.

    PubMed Central

    Calderone, R A; Braun, P C

    1991-01-01

    The cell surface of Candida albicans is composed of a variety of polysaccharides such as glucan, chitin, and mannan. The first two components primarily provide structure, while the mannan, often covalently linked to protein, constitutes the major antigen of the organism. Mannoproteins also have enzymatic activity (acid protease) and ligand-receptor functions. The complement receptors of C. albicans appear to be mannoproteins that are required for the adherence of the organism to endothelial cells. This is certainly true of the CR3-like protein of C. albicans. Proof that the CR3 is the Candida receptor for endothelial cells is derived from two observations. First, mutants lacking CR3 activity are less adherent in vitro and, in fact, less virulent. Second, the ligand recognized by the CR3 receptor (C3bi) as well as anti-CR3 antibodies blocks adherence of the organism to endothelial cells. The CR2 of C. albicans appears to promote the adherence of the organism to plastic substrates. Unlike the CR2 of mammalian cells, the Candida CR2 recognizes ligands containing the RGD sequence of amino acids in addition to the C3d ligand, which does not contain the RGD sequence. There is uncertainty as to whether the Candida CR2 and CR3 are, in fact, different proteins. A mannoprotein has also been described as the adhesin for epithelial cells. In this case, the receptor has a lectinlike activity and recognizes fucose- or glucosamine-containing glycoproteins of epithelial cells, depending on the strain of C. albicans. The oligosaccharide component of the receptor is probably not involved in ligand recognition and may serve to stabilize the receptor. However, the oligosaccharide factor 6 epitope of mannan may also provide adhesin activity in the recognition of epithelial cells. Mannoproteins can be extracted from cells by a number of reagents. Zymolyase, for instance, tends to remove structural mannoproteins, which contain relatively little protein and are linked to glucan. Reagents

  19. Nonlinear temperature dependence of glue-induced birefringence in polarization maintaining FBG sensors

    NASA Astrophysics Data System (ADS)

    Hopf, Barbara; Koch, Alexander W.; Roths, Johannes

    2016-05-01

    Glue-induced stresses decrease the accuracy of surface-mounted fiber Bragg gratings (FBG). Significant temperature dependent glue-induced birefringence was verified when a thermally cured epoxy-based bonding technique had been used. Determining the peak separation of two azimuthally aligned FBGs in PM fibers combined with a polarization resolved measurement set-up in a temperature range between -30°C and 150°C revealed high glue-induced stresses at low temperatures. Peak separations of about 60 pm and a nonlinear temperature dependence of the glue-induced birefringence due to stress relaxation processes and a visco-elastic behavior of the used adhesive have been shown.

  20. Force and temperature characteristics of a fs-laser machined locally micro-structured FBG

    NASA Astrophysics Data System (ADS)

    Dutz, Franz J.; Marchi, Gabriele; Stephan, Valentin; Huber, Heinz P.; Roths, Johannes

    2016-05-01

    A locally micro-structured fiber Bragg grating (LMFBG) was manufactured by forming a circumferential groove in the middle of a type I fiber Bragg grating (FBG). The groove was directly ablated using a fs-laser and had a length of 86μm, a depth of 27μm and steep side walls. Due to the precisely machined geometry of the structure the reflection spectra can be accurately described with a fairly simple theoretical model. At several constant temperatures in the range from 5°C to 45°C this structure was exposed to various compressive loads in the range from 0N to -1.42N. Here the force and temperature sensitivity of the LMFBG are presented. This structure can be used for miniaturized compressive force sensing at variable temperatures, which is of particular interest for many bio-medical applications.

  1. MBM fuel feeding system design and evaluation for FBG pilot plant

    SciTech Connect

    Campbell, William A.; Fonstad, Terry; Pugsley, Todd; Gerspacher, Regan

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer A 1-5 g/s fuel feeding system for pilot scale FBG was designed, built and tested. Black-Right-Pointing-Pointer Multiple conveying stages improve pressure balancing, flow control and stability. Black-Right-Pointing-Pointer Secondary conveyor stage reduced output irregularity from 47% to 15%. Black-Right-Pointing-Pointer Pneumatic air sparging effective in dealing with poor flow ability of MBM powder. Black-Right-Pointing-Pointer Pneumatic injection port plugs with char at gasification temperature of 850 Degree-Sign C. - Abstract: A biomass fuel feeding system has been designed, constructed and evaluated for a fluidized bed gasifier (FBG) pilot plant at the University of Saskatchewan (Saskatoon, SK, Canada). The system was designed for meat and bone meal (MBM) to be injected into the gasifier at a mass flow-rate range of 1-5 g/s. The designed system consists of two stages of screw conveyors, including a metering stage which controlled the flow-rate of fuel, a rotary airlock and an injection conveyor stage, which delivered that fuel at a consistent rate to the FBG. The rotary airlock which was placed between these conveyors, proved unable to maintain a pressure seal, thus the entire conveying system was sealed and pressurized. A pneumatic injection nozzle was also fabricated, tested and fitted to the end of the injection conveyor for direct injection and dispersal into the fluidized bed. The 150 mm metering screw conveyor was shown to effectively control the mass output rate of the system, across a fuel output range of 1-25 g/s, while the addition of the 50 mm injection screw conveyor reduced the irregularity (error) of the system output rate from 47% to 15%. Although material plugging was found to be an issue in the inlet hopper to the injection conveyor, the addition of air sparging ports and a system to pulse air into those ports was found to successfully eliminate this issue. The addition of the pneumatic injection nozzle

  2. Inhibition of Pneumococcal Adherence to Human Nasopharyngeal Epithelial Cells by Anti-PsaA Antibodies

    PubMed Central

    Romero-Steiner, Sandra; Pilishvili, Tamar; Sampson, Jacquelyn S.; Johnson, Scott E.; Stinson, Annie; Carlone, George M.; Ades, Edwin W.

    2003-01-01

    The role of pneumococcal (Pnc) surface adhesin A (PsaA) in the adherence of Streptococcus pneumoniae (pneumococcus) to host cells is not well defined. We examined the effect of anti-PsaA antibodies in an inhibition of adherence assay using Detroit 562 nasopharyngeal human epithelial cells. Rabbit polyclonal (Pab) anti-recombinant PsaA (rPsaA) sera, a purified mouse monoclonal antibody (MAb) (MAb 6F62G8E12), and 22 healthy adult sera with known anti-PsaA IgG levels (obtained by enzyme-linked immunosorbent assay) were evaluated for their abilities to inhibit Pnc adherence to confluent monolayers (measured as percent reduction in CFU counts compared to those of uninhibited controls). Pnc adherence was dependent on capsular phenotype (no or low adherence for opaque strains). With an inoculum of 104 to 105 bacteria/well, the mean ± standard deviation count in controls was 163 ± 32 CFU/well for transparent strains. Low adherence was observed for a PsaA-minus mutant even at higher inoculum doses. Mean percent inhibitions of adherence with Pab and MAb were 54 and 50%, respectively. Adult sera showed inhibition in a dose-response fashion with a range of 98 to 8%, depending on the serum anti-PsaA antibody concentration. Absorption of Pab with rPsaA restored Pnc adherence to control levels. Absorption of sera with a PsaA-minus mutant did not result in a significant decrease (P >0.05) of inhibition of adherence activity. Additionally, nearly 100% of Pnc adherence was inhibited by lipidated rPsaA at 2.5 μg/ml. Our data support the argument that PsaA is an adhesin that mediates Pnc adherence to human nasopharyngeal cells. This functional assay may be useful in evaluating antibodies elicited in response to PsaA vaccination. PMID:12626450

  3. Gauge factors of fibre Bragg grating strain sensors in different types of optical fibres

    NASA Astrophysics Data System (ADS)

    Jülich, Florian; Aulbach, Laura; Wilfert, Andre; Kratzer, Peter; Kuttler, Rolf; Roths, Johannes

    2013-09-01

    Gauge factors of fibre Bragg grating (FBG)-based strain sensors that had been inscribed into three different types of optical fibres, which differ in core diameters and doping concentrations, were determined at room temperature with high accuracy. Repeated measurements were carried out with several samples of each type of fibre to allow statistical evaluations. For each type, the gauge factors were measured in two configurations: when the bare fibres were glued on a specimen at the location of the FBG and when they were vertically suspended and not bonded to any structure at the location of the FBG. By combining the results of both configurations, the strain transfer ratio of the gluing process and the strain-optic coefficient, peff, of the different types of fibres were determined. The strain-optic coefficient was found to vary up to 1.5% for the different types of optical fibres. The strain transfer ratio was obtained to be close to unity (>99%), showing the high quality of the gluing technique employed. The investigations demonstrate that highly accurate strain sensing is possible with fibre-optic strain sensors. The results are important for the development of accurate and reliable attaching techniques for coated sensor fibres and fibre-optic sensor patches.

  4. Improving Patient's Primary Medication Adherence

    PubMed Central

    Leguelinel-Blache, Géraldine; Dubois, Florent; Bouvet, Sophie; Roux-Marson, Clarisse; Arnaud, Fabrice; Castelli, Christel; Ray, Valérie; Kinowski, Jean-Marie; Sotto, Albert

    2015-01-01

    Abstract Quality of transitions of care is one of the first concerns in patient safety. Redesigning the discharge process to incorporate clinical pharmacy activities could reduce the incidence of postdischarge adverse events by improving medication adherence. The present study investigated the value of pharmacist counseling sessions on primary medication adherence after hospital discharge. This study was conducted in a 1844-bed hospital in France. It was divided in an observational period and an interventional period of 3 months each. In both periods, ward-based clinical pharmacists performed medication reconciliation and inpatient follow-up. In interventional period, initial counseling and discharge counseling sessions were added to pharmaceutical care. The primary medication adherence was assessed by calling community pharmacists 7 days after patient discharge. We compared the measure of adherence between the patients from the observational period (n = 201) and the interventional period (n = 193). The rate of patients who were adherent increased from 51.0% to 66.7% between both periods (P < 0.01). When discharge counseling was performed (n = 78), this rate rose to 79.7% (P < 0.001). The multivariate regression performed on data from both periods showed that age of at least 78 years old, and 3 or less new medications on discharge order were predictive factors of adherence. New medications ordered at discharge represented 42.0% (n = 1018/2426) of all medications on discharge order. The rate of unfilled new medications decreased from 50.2% in the observational period to 32.5% in the interventional period (P < 10−7). However, patients included in the observational period were not significantly more often readmitted or visited the emergency department than the patients who experienced discharge counseling during the interventional period (45.3% vs. 46.2%; P = 0.89). This study highlights that discharge counseling sessions are

  5. Phylogenetic Analysis of Enteroaggregative and Diffusely Adherent Escherichia coli

    PubMed Central

    Czeczulin, John R.; Whittam, Thomas S.; Henderson, Ian R.; Navarro-Garcia, Fernando; Nataro, James P.

    1999-01-01

    The phylogenetics of the various pathotypes of diarrheagenic Escherichia coli are not completely understood. In this study, we identified several plasmid and chromosomal genes in the pathogenic enteroaggregative E. coli (EAEC) prototype strain 042 and determined the prevalence of these loci among EAEC and diffusely adherent E. coli strains. The distribution of these genes is analyzed within an evolutionary framework provided by the characterization of allelic variation in housekeeping genes via multilocus enzyme electrophoresis. Our data reveal that EAEC strains are heterogeneous with respect to chromosomal and plasmid-borne genes but that the majority harbor a member of a conserved family of virulence plasmids. Comparison of plasmid and chromosomal relatedness of strains suggests clonality of chromosomal markers and a limited transfer model of plasmid distribution. PMID:10338471

  6. Improving medication adherence in migraine treatment.

    PubMed

    Seng, Elizabeth K; Rains, Jeanetta A; Nicholson, Robert A; Lipton, Richard B

    2015-06-01

    Medication adherence is integral to successful treatment of migraine and other headache. The existing literature examining medication adherence in migraine is small, and the methodologies used to assess adherence are limited. However, these studies broadly suggest poor adherence to both acute and preventive migraine medications, with studies using more objective monitoring reporting lower adherence rates. Methods for improving medication adherence are described, including organizational strategies, provider-monitoring and self-monitoring of adherence, regimen strategies, patient education, self-management skills training (e.g., stimulus control, behavioral contracts), and cognitive-behavioral therapy techniques. The article concludes by discussing the future of research regarding adherence to medications for migraine and other headaches.

  7. Characterization of the adherence properties of Streptococcus salivarius.

    PubMed Central

    Weerkamp, A H; McBride, B C

    1980-01-01

    The adherence and aggregation properties of 46 human oral Streptococcus salivarius isolates were examined. A total of 41% of the isolates aggregated with whole human saliva, 50% aggregated with human erythrocytes, and 85% adhered to human buccal epithelial cells. Strains that aggregated with saliva and erythrocytes usually reacted with Streptococcus group K typing serum whereas the non-hemagglutinating strains did not. K+ strains also adhered more strongly to human buccal epithelial cells than K- strains. All isolates coaggregated with Fusobacterium nucleatum LF and Bacteroides asaccharolyticus 2D, 91% coaggregated with Veillonella alcalescens V1, and 50% coaggregated with Veillonella parvula V4. S. salivarius HB aggregated with saliva from 15 different human donors and aggregated with human erythrocytes irrespective of the blood group. This strain only weakly aggregated with rat saliva or rat erythrocytes. We isolated mutants which concomitantly lost the ability to agglutinate erythrocytes, aggregate with saliva, and bind to buccal epithelial cells, but retained their interbacterial aggregation properties. A second class of mutants lost the ability to coaggregate with Veillonella, but these mutants retained all of the other aggregation properties. Treatment of S. salivarius HB cells with pronase or subtilisin destroyed their ability to aggregate with saliva and erythrocytes and to bind to buccal epithelial cells. The unique characteristics of the aggregation and adherence reactions were suggested by differences in the rate of loss of activity during protease treatment and in the response to chemical modification. The presence of saliva did not affect hemagglutination and adherence to buccal epithelial cells. Binding of the salivary aggregating factor to the bacteria could be distinguished from aggregation on the basis that the latter required divalent cations. The factor involved in coaggregation with F. nucleatum LF was physicochemically different from the other

  8. Staphylococcus aureus adheres to human intestinal mucus but can be displaced by certain lactic acid bacteria.

    PubMed

    Vesterlund, Satu; Karp, Matti; Salminen, Seppo; Ouwehand, Arthur C

    2006-06-01

    There is increasing evidence that Staphylococcus aureus may colonize the intestinal tract, especially among hospitalized patients. As Staph. aureus has been found to be associated with certain gastrointestinal diseases, it has become important to study whether this bacterium can colonize the intestinal tract and if so, whether it is possible to prevent colonization. Adhesion is the first step in colonization; this study shows that Staph. aureus adheres to mucus from resected human intestinal tissue. Certain lactic acid bacteria (LAB), mainly commercial probiotics, were able to reduce adhesion and viability of adherent Staph. aureus. In displacement assays the amount of adherent Staph. aureus in human intestinal mucus was reduced 39-44% by Lactobacillus rhamnosus GG, Lactococcus lactis subsp. lactis and Propionibacterium freudenreichii subsp. shermanii. Moreover, adherent Lactobacillus reuteri, Lc. lactis and P. freudenreichii reduced viability of adherent Staph. aureus by 27-36%, depending on the strain, after 2 h incubation. This was probably due to the production of organic acids and hydrogen peroxide and possibly in the case of L. reuteri to the production of reuterin. This study shows for the first time that Staph. aureus can adhere to human intestinal mucus and adherent bacteria can be displaced and killed by certain LAB strains via in situ production of antimicrobial substances.

  9. Enhancing Adherence in Clinical Exercise Trials.

    ERIC Educational Resources Information Center

    O'Neal, Heather A.; Blair, Steven N.

    2001-01-01

    Discusses exercise adherence from the perspective of adhering to an exercise treatment in a controlled trial, focusing on: adherence (to intervention and measurement); the development of randomized clinical trials; exemplary randomized clinical trials in exercise science (exercise training studies and physical activity interventions); and study…

  10. Strain sensors for high field pulse magnets

    SciTech Connect

    Martinez, Christian; Zheng, Yan; Easton, Daniel; Farinholt, Kevin M; Park, Gyuhae

    2009-01-01

    In this paper we present an investigation into several strain sensing technologies that are being considered to monitor mechanical deformation within the steel reinforcement shells used in high field pulsed magnets. Such systems generally operate at cryogenic temperatures to mitigate heating issues that are inherent in the coils of nondestructive, high field pulsed magnets. The objective of this preliminary study is to characterize the performance of various strain sensing technologies at liquid nitrogen temperatures (-196 C). Four sensor types are considered in this investigation: fiber Bragg gratings (FBG), resistive foil strain gauges (RFSG), piezoelectric polymers (PVDF), and piezoceramics (PZT). Three operational conditions are considered for each sensor: bond integrity, sensitivity as a function of temperature, and thermal cycling effects. Several experiments were conducted as part of this study, investigating adhesion with various substrate materials (stainless steel, aluminum, and carbon fiber), sensitivity to static (FBG and RFSG) and dynamic (RFSG, PVDF and PZT) load conditions, and sensor diagnostics using PZT sensors. This work has been conducted in collaboration with the National High Magnetic Field Laboratory (NHMFL), and the results of this study will be used to identify the set of sensing technologies that would be best suited for integration within high field pulsed magnets at the NHMFL facility.

  11. Method of simultaneous measurement of two direction force and temperature using FBG sensor head.

    PubMed

    Kisała, Piotr; Cięszczyk, Sławomir

    2015-04-01

    This paper presents a method for measuring two components of bending force and temperature using one sensor head. Indirect inference based on the spectra of two fiber Bragg gratings (FBGs) placed on a cantilever beam is used. The method was developed during work on the inverse problem of determining a nonuniform stress distribution based on FBG spectra. A gradient in the FBG stress profile results in a characteristic shape of its reflective spectrum. The simultaneous measurements of force and temperature were possible through the use of an appropriate layout of the sensor head. The spectral characteristics of the sensor's gratings do not retain full symmetry, which is due to the geometry of the sensor's head and the related difference in the distribution of the axial stress of the gratings. In the proposed approach, the change in width of the sum of the normalized transmission spectra was used to determine the value of the applied force. In the presented method, an increase in the sensitivity of this change to the force is obtained relative to the other known systems. A change in the spectral width was observed for an increase in bending forces from 0 to 150 N. The sensitivity coefficient of the spectral width to force, defined as the ratio of the change of the spectral half-width to the change in force was 2.6e-3  nm/N for the first grating and 1.2e-3  nm/N for the second grating. However, the sensitivity of the whole sensor system was 5.8e-3  nm/N, which is greater than the sum of the sensitivities of the individual gratings. For the purpose of this work, a station with a thermal chamber has been designed with a bracket on which fiber optic transducers have been mounted for use in further measurements. The sensor head in this experiment is considered to be a universal device with potential applications in other types of optical sensors, and it can be treated as a module for development through its multiplication on a single optical fiber. PMID

  12. Performance of low-cost few-mode fiber Bragg grating sensor systems: polarization sensitivity and linearity of temperature and strain response.

    PubMed

    Ganziy, D; Rose, B; Bang, O

    2016-08-10

    We evaluate whether 850 nm fiber Bragg grating (FBG) sensor systems can use low-cost 1550 nm telecom fibers; in other words, how detrimental the influence of higher-order modes is to the polarization stability and linearity of the strain and temperature response. We do this by comparing polarization sensitivity of a few-mode 850 nm FBG sensor to a strictly single-mode 850 nm FBG sensor system using 850 nm single-mode fibers. We also compare the performance of the FBGs in strain and temperature tests. Our results show that the polarization stability and the linearity of the response degrade due to the presence of the higher-order modes. We demonstrate that, by using simple coiling of the 1550 nm fiber, one can regain the performance of the few-mode system and make it usable for high precision measurements. PMID:27534455

  13. Adherence of Veillonella Species Mediated by Extracellular Glucosyltransferase from Streptococcus salivarius

    PubMed Central

    McCabe, R. M.; Donkersloot, J. A.

    1977-01-01

    The effect of extracellular products from Streptococcus salivarius on sucrose-dependent adherence to smooth surfaces by other oral bacteria was studied in vitro. Strains of Streptococcus mitis, Streptococcus pyogenes, and Veillonella parvula without innate ability to adhere to a steel wire were able to do so when incubated with sucrose and cell-free culture fluid from S. salivarius strains 9759, 25975, CNII, and MEPI. These culture fluids synthesized more adherent material and water-insoluble glucan than those from Streptococcus mutans C67-1 and seven other S. salivarius strains. Among the S. salivarius strains, glucosyltransferase (GT; dextransucrase, EC 2.4.1.5) activity varied more than 100-fold. Cells of Veillonella and S. mitis S3 that had been incubated in culture fluids from S. salivarius 25975 and 9759, respectively, and then washed adhered upon subsequent incubation with sucrose. This was due to adsorbed GT because (i) the adherence was sensitive to dextranase; (ii) it was observed only with the high-GT culture fluids; (iii) it was dependent on sucrose; and (iv) the washed Veillonella cells synthesized glucan, but not fructan, from sucrose. These results suggest that sucrose-dependent adherence of bacteria without such innate ability can be mediated by (i) entrapment in insoluble glucan synthesized by S. salivarius culture fluids, and (ii) prior adsorption of GT from S. salivarius culture fluids. The possibility that GT formed by high-yield strains of S. salivarius is distributed through the mouth by the action of salivary flow and contributes to sucrose-dependent adherence and plaque formation is considered. Images PMID:591064

  14. Cryopreservation of adherent neuronal networks.

    PubMed

    Ma, Wu; O'Shaughnessy, Thomas; Chang, Eddie

    2006-07-31

    Neuronal networks have been widely used for neurophysiology, drug discovery and toxicity testing. An essential prerequisite for future widespread application of neuronal networks is the development of efficient cryopreservation protocols to facilitate their storage and transportation. Here is the first report on cryopreservation of mammalian adherent neuronal networks. Dissociated spinal cord cells were attached to a poly-d-lysine/laminin surface and allowed to form neuronal networks. Adherent neuronal networks were embedded in a thin film of collagen gel and loaded with trehalose prior to transfer to a freezing medium containing DMSO, FBS and culture medium. This was followed by a slow rate of cooling to -80 degrees C for 24 h and then storage for up to 2 months in liquid nitrogen at -196 degrees C. The three components: DMSO, collagen gel entrapment and trehalose loading combined provided the highest post-thaw viability, relative to individual or two component protocols. The post-thaw cells with this protocol demonstrated similar neuronal and astrocytic markers and morphological structure as those detected in unfrozen cells. Fluorescent dye FM1-43 staining revealed active recycling of synaptic vesicles upon depolarizing stimulation in the post-thaw neuronal networks. These results suggest that a combination of DMSO, collagen gel entrapment and trehalose loading can significantly improve conventional slow-cooling methods in cryopreservation of adherent neuronal networks.

  15. Experimental study of steel welded joints localization with using fiber Bragg grating strain sensor

    NASA Astrophysics Data System (ADS)

    Harasim, Damian

    2015-12-01

    Optical sensing systems has a not weakening research and development in recent years. Because of its unique properties of being unsusceptible to electromagnetic interference, having wide range of operational temperature and having extreme small physical dimensions, optical fiber sensors has increasing acceptance. Fiber Bragg Gratings (FBG) is the most frequently used type of optical sensor types because of its huge multiplexing potential and potentiality of being embedded into composite material (e.g. in structural health monitoring) or attached into measured structure. Embedding or attaching FBG into an inhomogeneous environment, spectral characteristic of the sensing grating do not retain full symmetry, which is due to related differences in the distribution of the axial stress of the grating. When periodicity of the grating is constant, the peak of FBG reflection spectrum should be narrow and sharp. An inhomogeneous axial strain distribution will cause a distorsion in measured transmission or reflection spectrum. This paper shows an distorsions in FBG reflection spectrum measured from sensor attached on surface with welded joint. The sensor strain-to-wavelength shift processing characteristics obtained for homogeneous and welded steel samples were compared.

  16. Development and application of optical fibre strain and pressure sensors for in-flight measurements

    NASA Astrophysics Data System (ADS)

    Lawson, N. J.; Correia, R.; James, S. W.; Partridge, M.; Staines, S. E.; Gautrey, J. E.; Garry, K. P.; Holt, J. C.; Tatam, R. P.

    2016-10-01

    Fibre optic based sensors are becoming increasingly viable as replacements for traditional flight test sensors. Here we present laboratory, wind tunnel and flight test results of fibre Bragg gratings (FBG) used to measure surface strain and an extrinsic fibre Fabry-Perot interferometric (EFFPI) sensor used to measure unsteady pressure. The calibrated full scale resolution and bandwidth of the FBG and EFFPI sensors were shown to be 0.29% at 2.5 kHz up to 600 μɛ and 0.15% at up to 10 kHz respectively up to 400 Pa. The wind tunnel tests, completed on a 30% scale model, allowed the EFFPI sensor to be developed before incorporation with the FBG system into a Bulldog aerobatic light aircraft. The aircraft was modified and certified based on Certification Standards 23 (CS-23) and flight tested with steady and dynamic manoeuvres. Aerobatic dynamic manoeuvres were performed in flight including a spin over a g-range  -1g to  +4g and demonstrated both the FBG and the EFFPI instruments to have sufficient resolution to analyse the wing strain and fuselage unsteady pressure characteristics. The steady manoeuvres from the EFFPI sensor matched the wind tunnel data to within experimental error while comparisons of the flight test and wind tunnel EFFPI results with a Kulite pressure sensor showed significant discrepancies between the two sets of data, greater than experimental error. This issue is discussed further in the paper.

  17. Safety monitoring of the FBG sensor in respect of radioactivity and deformation measurement of a silo structure for radioactive waste disposal

    NASA Astrophysics Data System (ADS)

    Kim, Ki-Soo; Cho, Seong-Kyu

    2015-07-01

    The FBG sensor has globally been commercialized in various fields that is actively applied in Korea as well. Especially it is widely used as a structural monitoring sensor in civil engineering and construction structures due to its advantages including electrical stability, chemical stability and multiplexing. This report aims to introduce safety inspection of the FBG sensor in respect of radioactivity which has been applied to a silo structure for radioactive waste disposal as an example.

  18. Demonstration of detectability of SHM system with FBG/PZT hybrid system in composite wing box structure

    NASA Astrophysics Data System (ADS)

    Soejima, Hideki; Ogisu, Toshimichi; Yoneda, Hiroshi; Okabe, Yoji; Takeda, Nobuo; Koshioka, Yasuhiro

    2008-03-01

    We have developed a novel damage monitoring system that can monitor the integrity of composite structures in aircrafts. In this system, fiber Bragg grating (FBG) sensors are used as sensors and piezoelectric transducers (PZT) are used as the generators of elastic waves that propagate in the structure to be inspected. The damage monitoring system can detect the structural integrity by the change in elastic waves that are detected by the FBG sensor and arrayed waveguide grating (AWG)-type filter. We confirmed that the structure health monitoring (SHM) system was able to monitor the damage initiation and propagation by a change in the waveform of the elastic waves in coupon specimens and structural element specimens. In this study, we demonstrate the detectability of the damage monitoring system by using a subcomponent test specimen that simulates an actual aircraft wing box structure composed of carbon fiber reinforced plastics (CFRPs). The FBG sensors and PZTs are bonded to the surfaces of hat-shaped stringers by an adhesive. Damages such as de-bonding and delamination are introduced in the bonded sections of the skin and stringers by impact. Damage monitoring and diagnosis are carried out by the SHM system under ambient conditions. We successfully verify the detectability of our system.

  19. Bisphosphonates adherence for treatment of osteoporosis

    PubMed Central

    2013-01-01

    Background Osteoporosis is a disease of bone metabolism in which bisphosphonates (BPS) are the most common medications used in its treatment, whose main objective is to reduce the risk of fractures. The aim of this study was to conduct a systematic review on BPs adherence for treatment of osteoporosis. Methods Systematic review of articles on BPs adherence for treatment of osteoporosis, indexed on MEDLINE (via PubMed) databases, from inception of databases until January 2013. Search terms were “Adherence, Medication” (MeSH term), “Bisphosphonates” (MeSH term), and “Osteoporosis” (MeSH term). Results Of the 78 identified studies, 27 met the eligibility criteria. Identified studies covered a wide range of aspects regarding adherence and associated factors, adherence and fracture, adherence and BPs dosage. The studies are mostly observational, conducted with women over 45 years old, showing low rates of adherence to treatment. Several factors may influence adherence: socio-economic and cultural, participation of physicians when guidance is given to the patient, the use of bone turnover markers, and use of generic drugs. The monthly dosage is associated with greater adherence compared to weekly dosage. Conclusions Considering the methodological differences between the studies, the results converge to show that adherence to treatment of osteoporosis with BPs is still inadequate. Further experimental studies are needed to evaluate the adherence and suggest new treatment options. PMID:23705998

  20. Ultra-weak FBG and its refractive index distribution in the drawing optical fiber.

    PubMed

    Guo, Huiyong; Liu, Fang; Yuan, Yinquan; Yu, Haihu; Yang, Minghong

    2015-02-23

    For the online writing of ultra-weak fiber Bragg gratings (FBGs) in the drawing optical fibers, the effects of the intensity profile, pulse fluctuation and pulse width of the excimer laser, as well as the transverse and longitudinal vibrations of the optical fiber have been investigated. Firstly, using Lorentz-Loren equation, Gladstone-Dale mixing rule and continuity equation, we have derived the refractive index (RI) fluctuation along the optical fiber and the RI distribution in the FBG, they are linear with the gradient of longitudinal vibration velocity. Then, we have prepared huge amounts of ultra-weak FBGs in the non-moving optical fiber and obtained their reflection spectra, the measured reflection spectra shows that the intensity profile and pulse fluctuation of the excimer laser, as well as the transverse vibration of the optical fiber are little responsible for the inconsistency of ultra-weak FBGs. Finally, the effect of the longitudinal vibration of the optical fiber on the inconsistency of ultra-weak FBGs has been discussed, and the vibration equations of the drawing optical fiber are given in the appendix. PMID:25836517

  1. FBG Sensor for Contact Level Monitoring and Prediction of Perforation in Cardiac Ablation

    PubMed Central

    Ho, Siu Chun Michael; Razavi, Mehdi; Nazeri, Alireza; Song, Gangbing

    2012-01-01

    Atrial fibrillation (AF) is the most common type of arrhythmia, and is characterized by a disordered contractile activity of the atria (top chambers of the heart). A popular treatment for AF is radiofrequency (RF) ablation. In about 2.4% of cardiac RF ablation procedures, the catheter is accidently pushed through the heart wall due to the application of excessive force. Despite the various capabilities of currently available technology, there has yet to be any data establishing how cardiac perforation can be reliably predicted. Thus, two new FBG based sensor prototypes were developed to monitor contact levels and predict perforation. Two live sheep were utilized during the study. It was observed during operation that peaks appeared in rhythm with the heart rate whenever firm contact was made between the sensor and the endocardial wall. The magnitude of these peaks varied with pressure applied by the operator. Lastly, transmural perforation of the left atrial wall was characterized by a visible loading phase and a rapid signal drop-off correlating to perforation. A possible pre-perforation signal was observed for the epoxy-based sensor in the form of a slight signal reversal (12–26% of loading phase magnitude) prior to perforation (occurring over 8 s). PMID:22368507

  2. Study and Test of a New Bundle-Structure Riser Stress Monitoring Sensor Based on FBG.

    PubMed

    Xu, Jian; Yang, Dexing; Qin, Chuan; Jiang, Yajun; Sheng, Leixiang; Jia, Xiangyun; Bai, Yang; Shen, Xiaohong; Wang, Haiyan; Deng, Xin; Xu, Liangbin; Jiang, Shiquan

    2015-11-24

    To meet the requirements of riser safety monitoring in offshore oil fields, a new Fiber Bragg Grating (FBG)-based bundle-structure riser stress monitoring sensor has been developed. In cooperation with many departments, a 49-day marine test in water depths of 1365 m and 1252 m was completed on the "HYSY-981" ocean oil drilling platform. No welding and pasting were used when the sensor was installed on risers. Therefore, the installation is convenient, reliable and harmless to risers. The continuous, reasonable, time-consistent data obtained indicates that the sensor worked normally under water. In all detailed working conditions, the test results show that the sensor can do well in reflecting stresses and bending moments both in and in magnitude. The measured maximum stress is 132.7 MPa, which is below the allowable stress. In drilling and testing conditions, the average riser stress was 86.6 MPa, which is within the range of the China National Offshore Oil Corporation (CNOOC) mechanical simulation results.

  3. Study and Test of a New Bundle-Structure Riser Stress Monitoring Sensor Based on FBG

    PubMed Central

    Xu, Jian; Yang, Dexing; Qin, Chuan; Jiang, Yajun; Sheng, Leixiang; Jia, Xiangyun; Bai, Yang; Shen, Xiaohong; Wang, Haiyan; Deng, Xin; Xu, Liangbin; Jiang, Shiquan

    2015-01-01

    To meet the requirements of riser safety monitoring in offshore oil fields, a new Fiber Bragg Grating (FBG)-based bundle-structure riser stress monitoring sensor has been developed. In cooperation with many departments, a 49-day marine test in water depths of 1365 m and 1252 m was completed on the “HYSY-981” ocean oil drilling platform. No welding and pasting were used when the sensor was installed on risers. Therefore, the installation is convenient, reliable and harmless to risers. The continuous, reasonable, time-consistent data obtained indicates that the sensor worked normally under water. In all detailed working conditions, the test results show that the sensor can do well in reflecting stresses and bending moments both in and in magnitude. The measured maximum stress is 132.7 MPa, which is below the allowable stress. In drilling and testing conditions, the average riser stress was 86.6 MPa, which is within the range of the China National Offshore Oil Corporation (CNOOC) mechanical simulation results. PMID:26610517

  4. FBG-based sensorized light pipe for robotic intraocular illumination facilitates bimanual retinal microsurgery.

    PubMed

    Horise, Yuki; He, Xingchi; Gehlbach, Peter; Taylor, Russell; Iordachita, Iulian

    2015-01-01

    In retinal surgery, microsurgical instruments such as micro forceps, scissors and picks are inserted through the eye wall via sclerotomies. A handheld intraocular light source is typically used to visualize the tools during the procedure. Retinal surgery requires precise and stable tool maneuvers as the surgical targets are micro scale, fragile and critical to function. Retinal surgeons typically control an active surgical tool with one hand and an illumination source with the other. In this paper, we present a "smart" light pipe that enables true bimanual surgery via utilization of an active, robot-assisted source of targeted illumination. The novel sensorized smart light pipe measures the contact force between the sclerotomy and its own shaft, thereby accommodating the motion of the patient's eye. Forces at the point of contact with the sclera are detected by fiber Bragg grating (FBG) sensors on the light pipe. Our calibration and validation results demonstrate reliable measurement of the contact force as well as location of the sclerotomy. Preliminary experiments have been conducted to functionally evaluate robotic intraocular illumination. PMID:26736189

  5. Study and Test of a New Bundle-Structure Riser Stress Monitoring Sensor Based on FBG.

    PubMed

    Xu, Jian; Yang, Dexing; Qin, Chuan; Jiang, Yajun; Sheng, Leixiang; Jia, Xiangyun; Bai, Yang; Shen, Xiaohong; Wang, Haiyan; Deng, Xin; Xu, Liangbin; Jiang, Shiquan

    2015-01-01

    To meet the requirements of riser safety monitoring in offshore oil fields, a new Fiber Bragg Grating (FBG)-based bundle-structure riser stress monitoring sensor has been developed. In cooperation with many departments, a 49-day marine test in water depths of 1365 m and 1252 m was completed on the "HYSY-981" ocean oil drilling platform. No welding and pasting were used when the sensor was installed on risers. Therefore, the installation is convenient, reliable and harmless to risers. The continuous, reasonable, time-consistent data obtained indicates that the sensor worked normally under water. In all detailed working conditions, the test results show that the sensor can do well in reflecting stresses and bending moments both in and in magnitude. The measured maximum stress is 132.7 MPa, which is below the allowable stress. In drilling and testing conditions, the average riser stress was 86.6 MPa, which is within the range of the China National Offshore Oil Corporation (CNOOC) mechanical simulation results. PMID:26610517

  6. Strain and high-temperature discrimination using a Type II fiber Bragg grating and a miniature fiber Fabry-Perot interferometer.

    PubMed

    Jiang, Yajun; Yang, Dexing; Yuan, Yuan; Xu, Jian; Li, Dong; Zhao, Jianlin

    2016-08-10

    A novel method for simultaneous measurement of strain and high temperature using a Type II fiber Bragg grating (FBG) and a miniature fiber Fabry-Perot interferometer (MFFPI) is proposed. The MFFPI is produced by fusion splicing a short section of quartz capillary tube with two single-mode fibers, and then it is exposed by a focused femtosecond laser and a phase mask to inscribe a Type II FBG nearby. The reflection spectrum of this sensor is the superposition of the reflection spectrum of the FBG and the interference fringe of the MFFPI. This sensor shows perfect high-temperature and strain responses. Because of the different responses to the uniform variations of strain and temperature, by measuring the reflection peak of FBG and one of the interference dips of the MFFPI, strain and temperature can be simultaneously determined. The resolutions of this particular sensor in measuring strain and temperature are estimated to be ±8.4  μϵ and ±3.3°C, respectively, in the range from 0 to 1122 μϵ and from 23°C to 600°C.

  7. Strain and high-temperature discrimination using a Type II fiber Bragg grating and a miniature fiber Fabry-Perot interferometer.

    PubMed

    Jiang, Yajun; Yang, Dexing; Yuan, Yuan; Xu, Jian; Li, Dong; Zhao, Jianlin

    2016-08-10

    A novel method for simultaneous measurement of strain and high temperature using a Type II fiber Bragg grating (FBG) and a miniature fiber Fabry-Perot interferometer (MFFPI) is proposed. The MFFPI is produced by fusion splicing a short section of quartz capillary tube with two single-mode fibers, and then it is exposed by a focused femtosecond laser and a phase mask to inscribe a Type II FBG nearby. The reflection spectrum of this sensor is the superposition of the reflection spectrum of the FBG and the interference fringe of the MFFPI. This sensor shows perfect high-temperature and strain responses. Because of the different responses to the uniform variations of strain and temperature, by measuring the reflection peak of FBG and one of the interference dips of the MFFPI, strain and temperature can be simultaneously determined. The resolutions of this particular sensor in measuring strain and temperature are estimated to be ±8.4  μϵ and ±3.3°C, respectively, in the range from 0 to 1122 μϵ and from 23°C to 600°C. PMID:27534477

  8. Adherence to Methotrexate therapy in Rheumatoid Arthritis

    PubMed Central

    Arshad, Nasim; Ahmad, Nighat Mir; Saeed, Muhammad Ahmed; Khan, Saira; Batool, Shabnam; Farman, Sumaira

    2016-01-01

    Objective: To determine adherence to methotrexate (MTX) therapy in patients with Rheumatoid Arthritis (RA) and to identify factors that promote either adherence or non adherence. Methods: One hundred Rheumatoid Arthritis patients on MTX for at least two months were enrolled. Questionnaire was completed by direct interview. Details recorded were, demographics (age, sex, education, monthly income), disease duration, duration on MTX and current dose. Disease Activity Score on 28 joint counts (DAS 28) at the current visit, concomitant drugs taken and number of doses of MTX missed in the previous 8 weeks were noted. Non adherence was defined as omission of any three or more prescribed doses of MTX in previous 8 week. Patients were asked for the factors that motivated their adherence to MTX as well as factors for non adherence. Presence of side effects due to MTX was also recorded. Result: Non adherence was found among 23% of cases. Patients of low socioeconomic group (p <0.0001) and on MTX for longer duration (p <0.001) had higher non adherence. Non adherent patients had significantly higher disease activity as measured by DAS 28 (p<0.001). Good counseling and education by the doctor was a strong predictor of adherence (p <0.001). Lack of affordability (p <0.001); lack of availability at local pharmacy (p <0.001); lack of family support (p <0.001) and lack of awareness regarding need and importance of MTX (p < 0.001were found as significant factors for non adherence. Conclusion: MTX non adherence in RA is noted in about one fourth of study group. Various economical and social issues lead to non adherence but good patient education and counseling by doctor could promote adherence in this study group. PMID:27182251

  9. Ultrahigh resolution fiber-optic quasi-static strain sensors for geophysical research

    NASA Astrophysics Data System (ADS)

    He, Zuyuan; Liu, Qingwen; Tokunaga, Tomochika

    2013-12-01

    A review of our recent work on ultrahigh resolution optical fiber sensors in the quasi-static region is presented, and their applications in crustal deformation measurement are introduced. Geophysical research such as studies on earthquake and volcano requires monitoring the earth's crustal deformation continuously with a strain resolution on the order of nano-strains (nɛ) in static to low frequency region. Optical fiber sensors are very attractive due to their unique advantages such as low cost, small size, and easy deployment. However, the resolution of conventional optical fiber strain sensors is far from satisfactory in the quasi-static domain. In this paper, several types of recently developed fiber-optic sensors with ultrahigh resolution in the quasi-static domain are introduced, including a fiber Bragg grating (FBG) sensor interrogated with a narrow linewidth tunable laser, an FBG based fiber Fabry-Perot interferometer (FFPI) sensor by using a phase modulation technique, and an FFPI sensor with a sideband interrogation technique. Quantificational analyses and field experimental results demonstrated that the FBG sensor can provide nano-order strain resolution. The sub-nano strain resolution was also achieved by the FFPI sensors in laboratory. Above achievements provide the basis to develop powerful fiber-optic tools for geophysical research on crustal deformation monitoring.

  10. Differences in Haemophilus parasuis adherence to and invasion of AOC-45 porcine aorta endothelial cells

    PubMed Central

    2013-01-01

    Background The pathogenesis of Haemophilus parasuis depends on the bacterium’s ability to interact with endothelial cells and invade adjacent tissues. In this study, we investigated the abilities of eight H. parasuis reference strains belonging to serovars 1, 2, 4, 5, 7, 9, 10 and 13 to adhere to and invade porcine aortic endothelial cells (AOC-45 cell line). Results The strains belonging to serovars 1, 2 and 5 were able to attach at high rates between 60 and 240 min of incubation, and serovars 4, 7 and 13 had moderate attachment rates; however, the strains belonging to serovars 9 and 10 had low adherence at all time points. Strong adherence was observed by scanning electron microscopy for the strains of serovars 5 and 4, which had high and moderate numbers, respectively, of H. parasuis cells attached to AOC-45 cells after 240 min of incubation. The highest invasiveness was reached at 180 min by the serovar 4 strain, followed by the serovar 5 strain at 240 min. The invasion results differed substantially depending on the strain. Conclusion The reference strains of H. parasuis serovars 1, 2, 4 and 5 exhibited high adhesion and invasion levels to AOC-45 porcine aorta endothelial cells, and these findings could aid to better explain the pathogenesis of the disease caused by these serovars. PMID:24119995

  11. Does adherence therapy improve medication adherence among patients with schizophrenia? A systematic review.

    PubMed

    Hegedüs, Anna; Kozel, Bernd

    2014-12-01

    Non-adherence to medication is highly prevalent in patients with schizophrenia. Adherence therapy aims to improve medication adherence of these patients by applying techniques of cognitive behavioural therapy, psycho-education, and motivational interviewing. Even though adherence therapy is frequently discussed and researched, its effectiveness is still uncertain. This paper aims to review the effectiveness of adherence therapy on the medication adherence of patients with schizophrenia. To this end, six electronic databases were systematically searched for randomized, controlled trials on adherence therapy from January 2002 to March 2013. Four trials met the inclusion criteria and were incorporated into the review. The findings suggest that adherence therapy does not improve patients' medication adherence in comparison to treatment as usual or a control intervention. However, all the studies reviewed showed high-adherence ratings at baseline. Thus, further well-designed studies that target adherence therapy to patients who are non-adherent to their medication are needed for a more profound understanding of its effectiveness. In addition, if adherence therapy is aimed not only at improving medication adherence, but also to reach an agreement whereby the patient's decision not to take his medication is accepted, the shared decision-making process needs to be assessed as well.

  12. Adherence of Pseudomonas aeruginosa to contact lenses

    SciTech Connect

    Miller, M.J.

    1988-01-01

    The purpose of this research was to examined the interactions of P. aeruginosa with hydrogel contact lenses and other substrata, and characterize adherence to lenses under various physiological and physicochemical conditions. Isolates adhered to polystyrene, glass, and hydrogel lenses. With certain lens types, radiolabeled cells showed decreased adherence with increasing water content of the lenses, however, this correlation with not found for all lenses. Adherence to rigid gas permeable lenses was markedly greater than adherence to hydrogels. Best adherence occurred near pH 7 and at a sodium chloride concentration of 50 mM. Passive adhesion of heat-killed cells to hydrogels was lower than the adherence obtained of viable cells. Adherence to hydrogels was enhanced by mucin, lactoferrin, lysozyme, IgA, bovine serum albumin, and a mixture of these macromolecules. Adherence to coated and uncoated lenses was greater with a daily-wear hydrogel when compared with an extended-wear hydrogel of similar polymer composition. Greater adherence was attributed to a higher concentration of adsorbed macromolecules on the 45% water-content lens in comparison to the 55% water-content lens.

  13. Association of coagulase-negative staphylococcal slime production and adherence with the development and outcome of adult septicemias.

    PubMed Central

    Kotilainen, P

    1990-01-01

    The relationship of coagulase-negative staphylococcal slime production and adherence with the development and outcome of bloodstream infections in two Finnish hospitals was evaluated. Analysis of 64 strains from 62 adult septicemias disclosed 34 (53%) adherent slime producers. In comparison, only 142 (29%) of 489 single blood culture isolates were adherent slime producers. Although tube adherence test-positive strains were significantly (P less than 0.001) more common among the septicemia strains than among clinically insignificant isolates, almost half of the septicemia cases were caused by tube test-negative strains. Thus, regarding any single patient isolate, a cautious posture to the clinical impact of positivity in the tube adherence test seems warranted. Moreover, adherence and slime production, as such, apparently played no role in the clinical outcome of these infections. The epidemiologic findings revealed that slime-producing coagulase-negative staphylococci were common in the hospital environment and suggested that epidemic spread of such strains was influenced by antimicrobial therapy. Collectively, these results indicate that, at least in these two hospitals, positivity in the tube was of minor importance in guiding clinical decisions in treating adult septicemias. PMID:2280010

  14. Adherence of Entamoeba histolytica trophozoites to rat and human colonic mucosa.

    PubMed Central

    Ravdin, J I; John, J E; Johnston, L I; Innes, D J; Guerrant, R L

    1985-01-01

    We studied the adherence of [3H]thymidine-labeled axenic Entamoeba histolytica (strain HM1-IMSS) to in vitro preparations of rat and human colonic mucosa. Studies were performed with fixed or unfixed rat colonic mucosa, unfixed rat mucosa exposed to trypsin, unfixed rat submucosa, and fixed human colonic mucosa. Twenty percent of the amebae adhered to fixed rat colonic mucosa; adherence was specifically inhibited by N-acetyl-D-galactosamine (GalNAc), galactose, and asialofetuin. The adherence of amebae to fixed human colonic mucosa was also GalNAc inhibitable. Greater adherence was found with unfixed rat colonic mucosa (40.9%) and was not GalNAc inhibitable unless the tissue was first exposed to trypsin. However, GalNAc did inhibit the adherence of amebae to unfixed rat submucosa. Glutaraldehyde fixation of amebae inactivates known amebic adhesion proteins; there was a markedly decreased adherence of fixed amebae to trypsin-exposed mucosa or fixed rat colonic mucosa. However, fixed or viable amebae had equal levels of adherence to unfixed rat colonic mucosa, suggesting the presence of a host adhesion protein that binds to receptors on amebae. Human (10%) and rabbit (5%) immune sera reduced the adherence of viable amebae to fixed rat colonic mucosa. We concluded that the GalNAc-inhibitable adhesion protein on the surface of E. histolytica trophozoites mediated adherence to fixed rat mucosa, fixed human colonic mucosa, trypsin-exposed unfixed rat mucosa, and unfixed rat submucosa. The surface of unfixed rat colonic mucosa contained a glutaraldehyde- and trypsin-sensitive host adhesion protein, perhaps in the overlying mucus blanket, which bound viable or fixed E. histolytica trophozoites. Images PMID:2580787

  15. Soil adherence to human skin

    SciTech Connect

    Driver, J.H.; Konz, J.J.; Whitmyre, G.K. )

    1989-12-01

    Dermal exposure to soils contaminated with toxic chemicals represents a potential public health hazard. These soils, contaminated with chemicals such as PCBs and dioxins, may be found at various locations throughout the US. Furthermore, dermal contact with pesticide-containing particles and contaminated soil particles is of importance for exposures to agricultural workers who reenter fields after pesticide application. With respect to dermal exposure to pesticide-contaminated particulate matter, several occurrences of human toxicity to ethyl parathion in citrus groves have been reported. These exposures resulted from dermal contact with high concentrations of the toxic transformation product paraoxon in soil dust contaminated as a result of application of pesticide to the overhead foliage of trees. To assess dermal exposure to chemically-contaminated soil at sites of concern, dermal adherence of soil must be determined prior to the assessment of dermal absorption. The purpose of the experiment reported herein was to determine the amount of soil (mg/cm{sup 2}) that adheres to adult hands under various soil conditions. These conditions include the type of soil, the organic content of the soil, and the particle size of the soil.

  16. Models for study of the specificity by which indigenous lactobacilli adhere to murine gastric epithelia.

    PubMed

    Kotarski, S F; Savage, D C

    1979-12-01

    A Lactobacillus strain isolated from a mouse (indigenous) and another strain isolated from swine feces (nonindigenous) were compared in two model systems for their ability to adhere in vitro and in vivo to keratinizing squamous and columnar epithelia of mouse stomachs. In one model, stomachs dissected from specific-pathogen-free or germfree mice were injected with suspensions of lactobacilli labeled with [(3)H]thymidine and incubated at 37 degrees C. Thereafter, the non-secreting and secreting tissues were separated and washed vigorously. The radioactivity remaining with each tissue was counted by liquid scintillation spectrometry. When the radioactivity remaining with these tissues ranged between 500 and 100,000 cpm, the calculated radioactivity (disintegrations per minute) was related linearly to the number of lactobacilli adhering to the tissue. The estimate of the number of bacteria adherent to the tissue was not influenced significantly by artifacts in the techniques used. In this model, both Lactobacillus strains adhered in equally high numbers to both types of epithelial surfaces from stomachs from germfree mice. In contrast, in the second model, in which germfree mice were monoassociated with one or the other of the Lactobacillus strains, only the strain indigenous to the mouse formed dense layers on the epithelia of the nonsecreting portions of the stomachs, although both strains maintained high population levels throughout the gastrointestinal tracts of the animals. The capacity to adhere to the mucosal surface is undoubtedly necessary for lactobacilli to colonize gastric epithelia in mice. Our findings suggest, however, that nutritional or environmental conditions dictate whether particular Lactobacillus strains can colonize particular surfaces in the stomachs of living animals.

  17. Role of Thin Fimbriae in Adherence and Growth of Acinetobacter calcoaceticus RAG-1 on Hexadecane.

    PubMed

    Rosenberg, M; Bayer, E A; Delarea, J; Rosenberg, E

    1982-10-01

    Acinetobacter calcoaceticus RAG-1, a hydrocarbon-degrading bacterium which adheres avidly to hydrocarbons and other hydrophobic surfaces, possesses numerous thin fimbriae (ca. 3.5-nm diameter) on the cell surface. MR-481, a nonadherent mutant of RAG-1 which is unable to grow on hexadecane under conditions of limited emulsification and low initial cell density, lacks these fimbriae. Prolonged incubation of MR-481 in hexadecane medium enriched for partial adherence revertants. The reappearance of thin fimbriae was observed in all such revertant strains. RAG-1 cells and partial revertant strains were agglutinated in the presence of antibody, whereas MR-481 cells were not. Another mutant, AB15, which was previously isolated on the basis of its nonagglutinability in the presence of antibody, also lacked thin fimbriae and was conditionally nonadherent. Furthermore, strain AB15 was unable to grow on hexadecane medium. Adherence of RAG-1 cells to hexadecane was considerably reduced after shearing treatment. The material removed from the cell surface by shearing of RAG-1 and the partial revertant strains yielded a single antigenic band in RAG-1 and partial revertant strains, as observed by crossed immunoelectrophoresis. This band was absent in both fimbriae-less mutants, MR-481 and AB15. The data demonstrate that the thin fimbriae of RAG-1 (i) are a major factor in adherence to polystyrene and hydrocarbon, (ii) may be crucial in enabling growth of cells on hexadecane, and (iii) constitute the major cell surface agglutinogen. PMID:16346118

  18. Improving hand hygiene adherence among nursing staff.

    PubMed

    Harne-Britner, Sarah; Allen, Marianne; Fowler, Kimberly A

    2011-01-01

    This quasi-experimental study explored initial and sustained effects of educational and behavioral interventions on hand hygiene adherence and the relationships between hand hygiene adherence and health care-associated infections. Education paired with positive reinforcement behavioral interventions significantly improved hand hygiene adherence after the first month (χ² = 4.27; P = .039); however, the improvement was not sustained over 6 months. There were no significant differences in infection rates between the treatment and control groups. PMID:20407392

  19. Adherence of clinically isolated lactobacilli to human cervical cells in competition with Neisseria gonorrhoeae.

    PubMed

    Vielfort, Katarina; Sjölinder, Hong; Roos, Stefan; Jonsson, Hans; Aro, Helena

    2008-10-01

    Lactobacilli are normal inhabitants of our microbiota and are known to protect against pathogens. Neisseria gonorrhoeae is a human specific pathogenic bacterium that colonises the urogenital tract where it causes gonorrhoea. In this study we analysed early interactions between lactobacilli and gonococci and investigated how they compete for adherence to human epithelial cervical cells. We show that lactobacilli adhere at various levels and that the number of adherent bacteria does not correlate to the level of protection against gonococcal infection. Protection against gonococcal adhesion varied between Lactobacillus species. Lactobacillus crispatus, Lactobacillus gasseri and Lactobacillus reuteri were capable of reducing gonococcal adherence while Lactobacillus rhamnosus was not. Lactobacillus strains of vaginal origin had the best capacity to remain attached to the host cell during gonococcal adherence. Further, we show that gonococci and lactobacilli interact with each other with resultant lactobacilli incorporation into the gonococcal microcolony. Hence, gonococci bind to colonised lactobacilli and this complex frequently detaches from the epithelial cell surface, resulting in reduced bacterial colonisation. Also, purified gonococcal pili are capable of removing adherent lactobacilli from the cell surface. Taken together, we reveal novel data regarding gonococcal and lactobacilli competition for adherence that will benefit future gonococcal prevention and treatments.

  20. Clostridium difficile toxin CDT hijacks microtubule organization and reroutes vesicle traffic to increase pathogen adherence.

    PubMed

    Schwan, Carsten; Kruppke, Anna S; Nölke, Thilo; Schumacher, Lucas; Koch-Nolte, Friedrich; Kudryashev, Mikhail; Stahlberg, Henning; Aktories, Klaus

    2014-02-11

    Clostridium difficile causes antibiotic-associated diarrhea and pseudomembranous colitis by the actions of Rho-glucosylating toxins A and B. Recently identified hypervirulent strains, which are associated with increased morbidity and mortality, additionally produce the actin-ADP-ribosylating toxin C. difficile transferase (CDT). CDT depolymerizes actin, causes formation of microtubule-based protrusions, and increases pathogen adherence. Here we show that CDT-induced protrusions allow vesicle traffic and contain endoplasmic reticulum tubules, connected to microtubules via the calcium sensor Stim1. The toxin reroutes Rab11-positive vesicles containing fibronectin, which is involved in bacterial adherence, from basolateral to the apical membrane sides in a microtubule- and Stim1-dependent manner. The data yield a model of C. difficile adherence regulated by actin depolymerization, microtubule restructuring, subsequent Stim1-dependent Ca(2+) signaling, vesicle rerouting, and secretion of ECM proteins to increase bacterial adherence.

  1. Histamine increases sickle erythrocyte adherence to endothelium.

    PubMed

    Wagner, Matthew C; Eckman, James R; Wick, Timothy M

    2006-02-01

    Complications of sickle cell anaemia include vascular occlusion triggered by the adherence of sickle erythrocytes to endothelium in the postcapillary venules. Adherence can be promoted by inflammatory mediators that induce endothelial cell adhesion molecule expression and arrest flowing erythrocytes. The present study characterised the effect of histamine stimulation on the kinetics of sickle cell adherence to large vessel and microvascular endothelium under physiological flow. Increased sickle cell adherence was observed within minutes of endothelial activation by histamine and reached a maximum value within 30 min. At steady state, sickle cell adherence to histamine-stimulated endothelium was 47 +/- 4 adherent cells/mm(2), 2.6-fold higher than sickle cell adherence to unstimulated endothelial cells. Histamine-induced sickle cell adherence occurred rapidly and transiently. Studies using histamine receptor agonists and antagonists suggest that histamine-induced sickle cell adhesion depends on simultaneous stimulation of the H(2) and H(4) histamine receptors and endothelial P-selectin expression. These data show that histamine release may promote sickle cell adherence and vaso-occlusion. In vivo histamine release should be studied to determine its role in sickle complications and whether blocking of specific histamine receptors may prevent clinical complications or adverse effects from histamine release stimulated by opiate analgesic treatment.

  2. Medication Adherence: A Call for Action

    PubMed Central

    Bosworth, Hayden B.; Granger, Bradi B.; Mendys, Phil; Brindis, Ralph; Burkholder, Rebecca; Czajkowski, Susan M.; Daniel, Jodi G.; Ekman, Inger; Ho, Michael; Johnson, Mimi; Kimmel, Stephen E.; Liu, Larry Z; Musaus, John; Shrank, William H.; Buono, Elizabeth Whalley; Weiss, Karen; Granger, Christopher B.

    2013-01-01

    Poor adherence to efficacious cardiovascular related medications has led to considerable morbidity, mortality, and avoidable health care costs. This paper provides results of a recent think tank meeting in which various stakeholder groups representing key experts from consumers, community health providers, the academic community, decision-making government officials (FDA, NIH, etc), and industry scientists met to evaluate the current status of medication adherence and provide recommendations for improving outcomes. Below, we review the magnitude of the problem of medication adherence, prevalence, impact, and cost. We then summarize proven effective approaches and conclude with a discussion of recommendations to address this growing and significant public health issue of medication non adherence. PMID:21884856

  3. Antihypertensive medication adherence among elderly Chinese Americans.

    PubMed

    Hsu, Ya-Hui; Mao, Chia-Ling; Wey, Mercy

    2010-10-01

    This study explored the level of antihypertensive medication adherence and examined certain demographic attributes and influential factors in relation to antihypertensive medication nonadherence among Chinese American elders using a descriptive cross-sectional survey design. Findings revealed that 52% of the elderly Chinese Americans adhered to their antihypertensive medications. Gender, education, years of residency in the United States, years of diagnosed hypertension, and perceived safety of taking antihypertensive medications did not contribute to the differences in medication adherence. Forgetfulness, medication adverse effects, language difficulties, and cultural barriers were the influential factors that hinder antihypertensive medication adherence. Developing effective and culturally appropriate strategies for Chinese American elders is recommended.

  4. [Treatment adherence and chronic inflammatory bowel diseases].

    PubMed

    Tahri, Nabil

    2007-09-01

    For inflammatory bowel disease, unlike other chronic illnesses, there are sparse data available about patients' adherence to medication. The few studies vary widely, but noncompliance rates tend to be high, about 30-40%. Psychiatric disorders, including depression and anxiety, and poor patient-physician relationships are the most common causes of these patients' lack of adherence. Failure to adhere to prescribed medications increases risk of relapse and of colorectal cancer. Strategies that can improve adherence include establishing a partnership with the patient, simplifying the treatment regimen and increasing awareness through education and feedback.

  5. High temperature strain sensor based on a fiber Bragg grating and rhombus metal structure.

    PubMed

    Zhang, Liang; Liu, Yueming; Gao, Xiaoliang; Xia, Zhongcheng

    2015-10-01

    In this paper, a novel high temperature strain sensor based on a polyimide-coated fiber Bragg grating (FBG) and a rhombus metal structure is presented and experimentally demonstrated. By heating low softening point glass via a micro torch, the polyimide-coated FBG could be fixed into the rhombus metal structure. Consequently, when the rhombus structure is stretched and compressed, respectively, then the FBG will be subjected to a reverse state. Moreover, the strain sensitivity is controllable and enhanced by adjusting the dimension of the rhombus metal structure appropriately. The experiment was then carried out by using an equi-intensity cantilever beam and high temperature chamber, and the result showed that the proposed high temperature strain sensor could be used at the high temperature of 300°C. A resolution of ∼10  με has been experimentally achieved. The average wavelength strain sensitivity at 300°C is 1.821 and 1.814 pm/με, for the compressed and stretched states, respectively. PMID:26479639

  6. Dynamic fiber Bragg grating strain sensor using a wavelength-locked tunable fiber ring laser

    NASA Astrophysics Data System (ADS)

    Zhu, Yinian; Krishnaswamy, Sridhar

    2012-04-01

    The interrogation systems based on fiber-optic sensors are very attractive for the practical applications in structural health monitoring owing to a number of advantages of optical fiber elements over their electronic counterparts. Among the fiber-optic sensors, the fiber Bragg gratings (FBGs) have their own unique features to be widely used for detection of acoustic emission. We have developed a dynamic strain sensing system by using a tunable single longitudinal mode Erbium-doped fiber ring laser to be locked to the middle-reflection wavelength of the FBG as the demodulation technique. A proportional-integral-derivative device continuously controls the laser wavelength that is kept at the FBG middle-reflection wavelength, thus stabilizing the operating point against quasi-static perturbation, while the high frequency dynamic strain shifts the FBG reflection profile. The reflected power varies in proportion to the applied strain which can be derived directly from AC photocurrent of the reflected signal. We have designed and assembled a fourchannel demodulator system for simultaneous high frequency dynamic strain sensing.

  7. On the Effects of the Lateral Strains on the Fiber Bragg Grating Response

    PubMed Central

    Lai, Marco; Karalekas, Dimitris; Botsis, John

    2013-01-01

    In this paper, a combined experimental-numerical based work was undertaken to investigate the Bragg wavelength shift response of an embedded FBG sensor when subjected to different conditions of multi-axial loading (deformation). The following cases are examined: (a) when an isotropic host material with no constrains on planes normal to the embedded sensor's axis is biaxially loaded, (b) when the same isotropic host material is subjected to hydrostatic pressure and (c) when the hydrostatically loaded host material is an anisotropic one, as in the case of a composite material, where the optical fiber is embedded along the reinforcing fibers. The comparison of the experimental results and the finite element simulations shows that, when the axial strain on the FBG sensor is the dominant component, the standard wavelength-shift strain relation can be used even if large lateral strains apply on the sensor. However when this is not the case, large errors may be introduced in the conversion of the wavelength to axial strains on the fiber. This situation arises when the FBG is placed parallel to high modulus reinforcing fibers of a polymer composite. PMID:23429580

  8. Characterization of embedded fiber optic strain sensors into metallic structures via ultrasonic additive manufacturing

    NASA Astrophysics Data System (ADS)

    Schomer, John J.; Hehr, Adam J.; Dapino, Marcelo J.

    2016-04-01

    Fiber Bragg Grating (FBG) sensors measure deviation in a reflected wavelength of light to detect in-situ strain. These sensors are immune to electromagnetic interference, and the inclusion of multiple FBGs on the same fiber allows for a seamlessly integrated sensing network. FBGs are attractive for embedded sensing in aerospace applications due to their small noninvasive size and prospect of constant, real-time nondestructive evaluation. In this study, FBG sensors are embedded in aluminum 6061 via ultrasonic additive manufacturing (UAM), a rapid prototyping process that uses high power ultrasonic vibrations to weld similar and dissimilar metal foils together. UAM was chosen due to the desire to embed FBG sensors at low temperatures, a requirement that excludes other additive processes such as selective laser sintering or fusion deposition modeling. In this paper, the embedded FBGs are characterized in terms of birefringence losses, post embedding strain shifts, consolidation quality, and strain sensing performance. Sensors embedded into an ASTM test piece are compared against an exterior surface mounted foil strain gage at both room and elevated temperatures using cyclic tensile tests.

  9. Wing shaping and strain sensing using fiber optics

    NASA Astrophysics Data System (ADS)

    Mendoza, Sergio Licon

    Current technologies to measure strain rely on strain gauges that become heavy with increased measurement points. One significant improvement is the Fiber Bragg Gratings (FBG) which allows light to reflect through a fiber optic line in relation to the strain applied on that fiber. Significant advantages over conventional strain gauges allow for a light weight detailed view of the strain applied to any structure containing these fibers. The SPACE Center in conjunction with the AERO Institute have produced preliminary conclusions on how to implement such fibers on a wing structure and how they could be used to control the shape of a wing. Such a wing structure could be built lighter and flexible than today's wings thus enabling a lighter aircraft. Further studies show that if a feedback mechanism is encompassed, flutter suppression techniques can be accomplished with the use of these fibers thus avoiding catastrophic failure.

  10. Adherence of Streptococcus sanguis clinical isolates to smooth surfaces and interactions of the isolates with Streptococcus mutans glucosyltransferase.

    PubMed Central

    Hamada, S; Torii, M; Kotani, S; Tsuchitani, Y

    1981-01-01

    Streptococcus sanguis isolated from human dental plaque were grown in Todd-Hewitt broth. Cells were collected by centrifugation and lyophilized after extensive washing with water. The cell-associated glucosyltransferase (GTase) activities of S. sanguis strains were assayed with [14C]sucrose. Strain differences in GTase activity were significant within the same serotype or biotype or both. The ability of S. sanguis cells to adhere to smooth glass surfaces was generally weak, irrespective of significant cell-associated GTase activity synthesizing water-insoluble, gel-like glucans. Resting cells of most S. sanguis strains bound extracellular GTase from Streptococcus mutans strain B13 (serotype d), resulting in the strong adherence of the S. sanguis cells to smooth glass surfaces in the presence of sucrose. Conversely, S. mutans B13 cells also could bind extracellular GTase from some strains of S. sanguis examined. The sucrose-dependent adherence of S. mutans cells was not altered, although S. sanguis strains from which the extracellular GTases were obtained did not produce significant adherence in the presence of sucrose. In view of these findings, it was suggested that S. mutans GTase could affect the adherence of S. sanguis to smooth tooth surfaces in the oral cavity. Images PMID:6452415

  11. Apodized fibre Bragg grating acousto-ultrasonic sensor under arbitrary strain using dual Fabry Perot filters

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Ryul; Tsuda, Hiroshi; Akimune, Yoshio

    2007-01-01

    This paper describes a novel acousto-ultrasonic (AU) sensing system in which a fibre Bragg grating (FBG) is permanently built in a structure for in situ health monitoring. The AU wave detection using an FBG can be realized by a demodulation technique using an optical filter or light source narrower than the FBG spectrum. However, since the spectral wavelength shift induced from structural strain is much larger than the spectral oscillation induced from the AU wave, it is difficult for the demodulation wavelength to follow the spectral shift. For this work, we introduce a passive demodulation method regardless of the spectral shift based on an apodized FBG (AFBG) and dual fibre Fabry-Perot (FFP) filters. The free spectral range (FSR) of a high-finesse FFP filter is matched to the full-bandwidth of the AFBG without side lobes. Therefore, a part of the AFBG spectrum is always filtered by one of the multiple interferometric peaks. However, the wavelength regime near the maximum or minimum reflectivity of the AFBG provides insufficient sensitivity with respect to the wave. Therefore, another 1/4 FSR-biased FFP filter with the same FSR is simultaneously operated.

  12. Adherence of sputtered titanium carbides

    NASA Technical Reports Server (NTRS)

    Brainard, W. A.; Wheeler, D. R.

    1979-01-01

    The study searches for interface treatment that would increase the adhesion of TiC coating to nickel- and titanium-base alloys. Rene 41 (19 wt percent Cr, 11 wt percent Mo, 3 wt percent Ti, balance Ni) and Ti-6Al-4V (6 wt percent Al, 4 wt percent V, balance Ti) are considered. Adhesion of the coatings is evaluated in pin-and disk friction tests. The coatings and interface regions are examined by X-ray photoelectron spectroscopy. Results suggest that sputtered refractory compound coatings adhere best when a mixed compound of coating and substrate metals is formed in the interfacial region. The most effective type of refractory compound interface appears to depend on both substrate and coating material. A combination of metallic interlayer deposition and mixed compound interface formation may be more effective for some substrate coating combinations than either alone.

  13. Adherence of Streptococcus salivarius HB and HB-7 to oral surfaces and saliva-coated hydroxyapatite.

    PubMed Central

    Weerkamp, A H; McBride, B C

    1980-01-01

    We compared the binding of Streptococcus salivarius HB and the mutant HB-7 to oral surfaces in vivo. Mutant HB-7 does not aggregate with saliva nor does it bind to buccal epithelium, but it does retain its ability to coaggregate with Veillonella and Fusobacterium. At 1 h after inoculation into the oral cavity of six volunteers, significantly more S. salivarius HB than HB-7 cells were found adhering to the buccal mucosa (P < 0.05) and to a cleaned tooth surface (P < 0.01); there was no significant difference in the numbers adhering to the tongue. The ratio of HB to HB-7 on the tongue increased in samples taken 1, 3, and 9 days after inoculation. The average time required to clear the mutant HB-7 from the oral cavity was 7 days, whereas that for the parent HB was greater than 20 days, and in some cases strain HB was still present 3 months after its inoculation. A representative S. salivarius serotype II strain, designated T3, behaved similarly to mutant HB-7 with respect to its adherence to the buccal mucosa. Strain HB adhered better to hydroxyapatite treated with human saliva than mutant HB-7; both strains adhered in similar numbers to untreated hydroxyapatite. Hydroxyapatite treated with rat saliva bound less HB than hydroxyapatite treated with human saliva, corresponding to the lower aggregating activity of rat saliva. Extraction of saliva with aggregating strains of S. salivarius reduced the ability of saliva to mediate attachment of strain HB to hydroxyapatite. PMID:7439971

  14. Acinetobacter baumannii and A. pittii clinical isolates lack adherence and cytotoxicity to lung epithelial cells in vitro.

    PubMed

    Lázaro-Díez, María; Navascués-Lejarza, Teresa; Remuzgo-Martínez, Sara; Navas, Jesús; Icardo, José Manuel; Acosta, Felix; Martínez-Martínez, Luis; Ramos-Vivas, José

    2016-09-01

    The molecular and genetic basis of Acinetobacter baumannii and Acinetobacter pittii virulence remains poorly understood, and there is still lack of knowledge in host cell response to these bacteria. In this study, we have used eleven clinical Acinetobacter strains (A. baumannii n = 5; A. pittii n = 6) to unravel bacterial adherence, invasion and cytotoxicity to human lung epithelial cells. Our results showed that adherence to epithelial cells by Acinetobacter strains is scarce and cellular invasion was not truly detected. In addition, all Acinetobacter strains failed to induce any cytotoxic effect on A549 cells.

  15. Adherence of Staphylococcus epidermidis to human endothelial cells is associated with a polysaccharidic component of its extracellular mucous layer.

    PubMed

    Krevvata, Maria I; Spiliopoulou, Anastasia; Anastassiou, Evangelos D; Karamanos, Nikos; Kolonitsiou, Fevronia

    2011-06-01

    Bacterial adherence to eukaryotic cells is highly contributing to microbial pathogenesis. Bacterial adhesins, macromolecules, and glycosaminoglycan chains of the endothelial cell surface have been implicated in staphylococcal attachment. Our research group has isolated an antigenic polysaccharidic component of Staphylococcus epidermidis extracellular layer, known as 20-kDa PS (PS), and showed that antibodies against this polysaccharide protect from infections. Therefore, the role of PS in S. epidermidis adherence to endothelial cells was studied. For this purpose we examined the impact of PS on the ability of two S. epidermidis strains (a PS-producing and a non-PS-producing strain) to adhere to human endothelial cells in the presence or absence of specific antibodies to this polysaccharide. Hence, it is established that exogenous chondroitin sulfate (CS) decreases, in part, the S. epidermidis' attachment to endothelial cells and the antagonistic binding effect of CS and PS was also studied. The results obtained demonstrate that PS facilitates the adherence of S. epidermidis to both strains. CS abolished the PS-induced adherence in PS-producing strain and partially in the non-PS-producing one. Conclusively, the adherence of S. epidermidis to human endothelial cells is associated with its extracellular PS component and it is suggested that the bacterial binding via glycosaminoglycan chains is an important mechanism underlining the PS-induced binding to endothelial cells.

  16. Intent-to-adhere and adherence to malaria prevention recommendations in two travel clinics.

    PubMed

    Goldstein, Irit; Grefat, Rami; Ephros, Moshe; Rishpon, Shmuel

    2015-01-01

    Malaria infects 30,000 travelers annually worldwide. At greatest risk are those who travel for long duration. Prevention of malaria includes chemoprophylaxis. This prospective study on 121 travelers who visited two travel clinics shows that adherence to prophylactic treatment was low, especially in long duration trips, and that adherence rate could be predicted by the much more available intent-to-adhere rate.

  17. A novel wide measuring range FBG displacement sensor with variable measurement precision based on helical bevel gear

    NASA Astrophysics Data System (ADS)

    Jiang, Shan-chao; Wang, Jing; Sui, Qing-mei; Cao, Yu-qiang

    2015-03-01

    A novel fiber Bragg grating (FBG) displacement sensor is proposed, which can achieve wide measuring range displacement detection with variable measurement precision due to its mechanical transfer structure of helical bevel gear. A prototype is designed and fabricated. The maximum detection displacement of this prototype is 1.751 m, and the precision grade changes from 0.2% to 6.7%. Through analyzing the experiment data which is obtained in the calibration experiment, the measuring range of this sensor is from 0 m to 1.532 m, and the wavelength shift errors between experiment data and theory calculation are all less than 5%.

  18. Prebiotic Galactooligosaccharides Reduce Adherence of Enteropathogenic Escherichia coli to Tissue Culture Cells▿

    PubMed Central

    Shoaf, Kari; Mulvey, George L.; Armstrong, Glen D.; Hutkins, Robert W.

    2006-01-01

    Prebiotic oligosaccharides are thought to provide beneficial effects in the gastrointestinal tract of humans and animals by stimulating growth of selected members of the intestinal microflora. Another means by which prebiotic oligosaccharides may confer health benefits is via their antiadhesive activity. Specifically, these oligosaccharides may directly inhibit infections by enteric pathogens due to their ability to act as structural mimics of the pathogen binding sites that coat the surface of gastrointestinal epithelial cells. In this study, the ability of commercial prebiotics to inhibit attachment of microcolony-forming enteropathogenic Escherichia coli (EPEC) was investigated. The adherence of EPEC strain E2348/69 on HEp-2 and Caco-2 cells, in the presence of fructooligosaccharides, inulin, galactooligosaccharides (GOS), lactulose, and raffinose was determined by cultural enumeration and microscopy. Purified GOS exhibited the greatest adherence inhibition on both HEp-2 and Caco-2 cells, reducing the adherence of EPEC by 65 and 70%, respectively. In addition, the average number of bacteria per microcolony was significantly reduced from 14 to 4 when GOS was present. Adherence inhibition by GOS was dose dependent, reaching a maximum at 16 mg/ml. When GOS was added to adhered EPEC cells, no displacement was observed. The expression of BfpA, a bundle-forming-pilus protein involved in localized adherence, was not affected by GOS, indicating that adherence inhibition was not due to the absence of this adherence factor. In addition, GOS did not affect autoaggregation. These observations suggest that some prebiotic oligosaccharides may have antiadhesive activity and directly inhibit the adherence of pathogens to the host epithelial cell surface. PMID:16982832

  19. A Review of Treatment Adherence Measurement Methods

    ERIC Educational Resources Information Center

    Schoenwald, Sonja K.; Garland, Ann F.

    2013-01-01

    Fidelity measurement is critical for testing the effectiveness and implementation in practice of psychosocial interventions. Adherence is a critical component of fidelity. The purposes of this review were to catalogue adherence measurement methods and assess existing evidence for the valid and reliable use of the scores that they generate and the…

  20. Motivating patient adherence to allergic rhinitis treatments.

    PubMed

    Bender, Bruce G

    2015-03-01

    Patient nonadherence significantly burdens the treatment of allergic rhinitis (AR). Fewer than half of prescribed doses of intranasal corticosteroid medication are taken. The challenges for immunotherapies are even greater. While sustained treatment for 3 to 5 years is required for full benefit, most patients receiving immunotherapy, either subcutaneous or sublingual, stop treatment within the first year. Although research into interventions to improve AR adherence is lacking, lessons learned from adherence interventions in other chronic health conditions can be applied to AR. Two well-established, overriding models of care-the chronic care model and patient-centered care-can improve adherence. The patient-centered care model includes important lessons for allergy providers in their daily practice, including understanding and targeting modifiable barriers to adherence. Additionally, recent studies have begun to leverage health information and communication technologies to reach out to patients and promote adherence, extending patient-centered interventions initiated by providers during office visits.

  1. Motivating patient adherence to allergic rhinitis treatments.

    PubMed

    Bender, Bruce G

    2015-03-01

    Patient nonadherence significantly burdens the treatment of allergic rhinitis (AR). Fewer than half of prescribed doses of intranasal corticosteroid medication are taken. The challenges for immunotherapies are even greater. While sustained treatment for 3 to 5 years is required for full benefit, most patients receiving immunotherapy, either subcutaneous or sublingual, stop treatment within the first year. Although research into interventions to improve AR adherence is lacking, lessons learned from adherence interventions in other chronic health conditions can be applied to AR. Two well-established, overriding models of care-the chronic care model and patient-centered care-can improve adherence. The patient-centered care model includes important lessons for allergy providers in their daily practice, including understanding and targeting modifiable barriers to adherence. Additionally, recent studies have begun to leverage health information and communication technologies to reach out to patients and promote adherence, extending patient-centered interventions initiated by providers during office visits. PMID:25956611

  2. Adherence to guidelines in gynecologic cancer surgery.

    PubMed

    Ferron, Gwenael; Martinez, Alejandra; Gladieff, Laurence; Mery, Eliane; David, Isabelle; Delannes, Martine; Montastruc, Marion; Balagué, Gisèle; Picaud, Laetitia; Querleu, Denis

    2014-11-01

    The purpose of this study is to review the available evidence documenting the prognostic role of adherence to guidelines in gynecologic cancers. A systematic review of the PubMed database using "guideline," "adherence," and "cancer" was carried out on February 25, 2014. Two thousand one hundred twenty-three publications were identified. Only publications addressing the question of adherence to recommendations regarding surgical care and multidisciplinary management of gynecologic cancers were selected. Six studies were identified in endometrial cancer, 4 in ovarian cancer, and none in cervical cancer. Adoption of guidelines is an effective tool for disease control and must consequently be considered as a process measure of quality cancer care. It is urgent to develop reliable and reproducible tools to assess adherence to guidelines based on level 1 evidence in gynecologic cancer then to carry out investigations to document the prognostic impact of compliance with guidelines. The time has come to include adherence to guidelines in quality assurance programs. PMID:25340292

  3. Adherence to Antiretroviral Therapy and Virologic Failure

    PubMed Central

    Bezabhe, Woldesellassie M.; Chalmers, Leanne; Bereznicki, Luke R.; Peterson, Gregory M.

    2016-01-01

    Abstract The often cited need to achieve ≥95% (nearly perfect) adherence to antiretroviral therapy (ART) for successful virologic outcomes in HIV may present a barrier to initiation of therapy in the early stages of HIV. This meta-analysis synthesized 43 studies (27,905 participants) performed across >26 countries, to determine the relationship between cut-off point for optimal adherence to ART and virologic outcomes. Meta-analysis was performed using a random-effect model to calculate pooled odds ratios with corresponding 95% confidence intervals. The mean rate of patients reporting optimal adherence was 63.4%. Compared with suboptimal adherence, optimal adherence was associated with a lower risk of virologic failure (0.34; 95% CI: 0.26–0.44). There were no significant differences in the pooled odds ratios among different optimal adherence thresholds (≥98–100%, ≥95%, ≥80–90%). Study design (randomized controlled trial vs observational study) (regression coefficient 0.74, 95% CI: 0.04–1.43, P < 0.05) and study region (developing vs developed countries; regression coefficient 0.56, 95% CI: 0.01–1.12, P < 0.05) remained as independent predictors of between-study heterogeneity, with more patients with optimal adherence from developing countries or randomized controlled trials experiencing virologic failure. The threshold for optimal adherence to achieve better virologic outcomes appears to be wider than the commonly used cut-off point (≥95% adherence). The cut-off point for optimal adherence could be redefined to a slightly lower level to encourage the prescribing ART at an early stage of HIV infection. PMID:27082595

  4. Recent advances in adherence and invasion of pathogenic Escherichia coli

    PubMed Central

    Kalita, Anjana; Hu, Jia; Torres, Alfredo G.

    2014-01-01

    Purpose of review Colonization of the host epithelia by pathogenic Escherichia coli is influenced by the ability of the bacteria to interact with host surfaces. Because the initial step of an E. coli infection is to adhere, invade, and persist within host cells, some strategies used by intestinal and extra-intestinal E. coli to infect host cell are presented. Recent findings This review highlights recent progress understanding how extra-intestinal pathogenic E. coli strains express specific adhesins/invasins that allow colonization of the urinary tract or the meninges, while intestinal E. coli strains are able to colonize different regions of the intestinal tract using other specialized adhesins/invasins. Finally, evaluation of, different diets and environmental conditions regulating the colonization of these pathogens is discussed. Summary Discovery of new interactions between pathogenic E. coli and the host epithelial cells unravels the need of more mechanistic studies that can provide new clues in how to combat these infections. PMID:25023740

  5. A fiber optic buckle transducer for measurement of in vitro tendon strain

    NASA Astrophysics Data System (ADS)

    Roriz, Paulo; Ramos, António; Marques, Manuel B.; Simões, José A.; Frazão, Orlando

    2015-09-01

    The purpose of the present study is to present a prototype of a fiber optic based buckle transducer suitable for measuring strain caused by stretching of a tendon. The device has an E-shape and its central arm is instrumented with a fiber Bragg grating (FBG) sensor. The tendon adjusts to the E-form in a fashion that when it is stretched the central arm bends causing a shift of the Bragg's wavelength (λB) that is proportional to the amount of strain. This prototype is presented as an alternative to conventional strain gauge (SG) buckle transducers.

  6. Ultra-short FBG based distributed sensing using shifted optical Gaussian filters and microwave-network analysis.

    PubMed

    Cheng, Rui; Xia, Li; Sima, Chaotan; Ran, Yanli; Rohollahnejad, Jalal; Zhou, Jiaao; Wen, Yongqiang; Yu, Can

    2016-02-01

    Ultrashort fiber Bragg gratings (US-FBGs) have significant potential as weak grating sensors for distributed sensing, but the exploitation have been limited by their inherent broad spectra that are undesirable for most traditional wavelength measurements. To address this, we have recently introduced a new interrogation concept using shifted optical Gaussian filters (SOGF) which is well suitable for US-FBG measurements. Here, we apply it to demonstrate, for the first time, an US-FBG-based self-referencing distributed optical sensing technique, with the advantages of adjustable sensitivity and range, high-speed and wide-range (potentially >14000 με) intensity-based detection, and resistance to disturbance by nonuniform parameter distribution. The entire system is essentially based on a microwave network, which incorporates the SOGF with a fiber delay-line between the two arms. Differential detections of the cascaded US-FBGs are performed individually in the network time-domain response which can be obtained by analyzing its complex frequency response. Experimental results are presented and discussed using eight cascaded US-FBGs. A comprehensive numerical analysis is also conducted to assess the system performance, which shows that the use of US-FBGs instead of conventional weak FBGs could significantly improve the power budget and capacity of the distributed sensing system while maintaining the crosstalk level and intensity decay rate, providing a promising route for future sensing applications. PMID:26906822

  7. One year of FBG-based thermo-hygrometers in operation in the CMS experiment at CERN

    NASA Astrophysics Data System (ADS)

    Berruti, Gaia Maria; Petagna, Paolo; Buontempo, Salvatore; Makovec, Alajos; Szillasi, Zoltan; Beni, Noemi; Consales, Marco; Cusano, Andrea

    2016-03-01

    In this contribution we present results concerning the very first application of fiber optic sensors (FOSs) for relative humidity (RH) monitoring in high radiations environments. After a few years of investigations at CERN in Geneva, since December 2013 our multidisciplinary research group has successfully installed 72 thermo-hygrometers based on Fiber Bragg Grating (FBG) technology, organized in multi-points arrays, in cold areas of the Tracker Bulkhead of the Compact Muon Solenoid (CMS) experiment, where hundreds of electrical connectors are housed and thousands of services, including many cold pipes, cross the volumes through them. In such a complicated environment, a constant hygrometric monitoring is vital, in order to avoid dangerous phenomena of condensation. The collected results in the last year of operation of the proposed sensors are effective and reliable, with temperature, relative humidity and dew point temperature measurements from the FBG-based devices in full agreement with the readings of conventional sensors, temporarily present in the detector. However, experience in operation has shown some limitations of this technology, which are fully detailed in the last section of the paper.

  8. Performance of a movable flexible pipe-encapsulated FBG sensor developed for shape monitoring of multi-layered pavement structure

    NASA Astrophysics Data System (ADS)

    Wang, Huaping; Liu, Wanqiu; Zhou, Zhi

    2014-03-01

    The large span and heterogeneous components of multi-layered pavement structure usually bring about stochastic damage, and many modern approaches, such as ground penetrating radar, integral imaging and optical fiber sensing technology, have been employed to detect the degeneration mechanism. Restricted by the cost and universality, novel elements for pavement monitoring are in high demand. Optical fiber sensing technology for high sensitivity, long stability, anti-corrosion and resistance to water erosion then is considered. Therefore, a movable FBG sensor located in flexible pipe is developed, which has long stroke inside inner wall of the hollow pipe, and a full-scale shape of the structure could be sketched just with one FBG. Theoretical and experimental methods about establishing the relationship between wavelength variable and curvature have been provided, and function about reconfiguring the coordinate is converted to a mathematic question. Move over, transfer error modification has been taken into account for modify related error. Multi-layered pavement model embedded with this sensor will be accomplished to inspect its performance in later work. The work in the paper affords a feasible method for shape monitoring and would be potentially valuable for the maintenance and inverse design of pavement structure.

  9. [Study of antibiotic influence on adherence capacity of gram positive and gram negative bacteria to the cellular substrate].

    PubMed

    Balotescu, Carmen; Israil, Anca-Michaela; Lazăr, Veronica; Cernat, Ramona; Petrache, Lia-Mara; Dinu, Cristina

    2002-01-01

    Bacterial adherence to the cellular substrate (skin and mucosa) represents a precondition of infectious pathology. It was demonstrated that bacteria which adhere and form biofilms on catheters and other inert materials used in medicine are resistant to the therapeutic antibiotic concentrations being protected by the biofilm mathrix and generating severe and hard to treat infections. There are only few studies on the influence of antibiotics on the bacterial adhesins synthesis and bacterial adherence to the cellular substrate. The purpose of this study was to investigate the influence of subinhibitory concentrations of antibiotics on adherence capacity of Listeria monocytogenes, Vibrio cholerae and Aeromonas hydrophyla to the cellular substrate represented by HEp-2 cells. Suspensions (approximately 10(10) cells/ml) of bacterial cultures developed on solid media were incubated for 30 minutes in the presence of subinhibitory concentrations of penicillin, ampicillin, amoxicilin with clavulanic acid, ceftazidim, norfloxacin, kanamycin, chloramphenicole and vancomycin. Study of bacterial adherence to the cellular substrate was done by Cravioto's modified method. The quantitative evaluation of adherence/invasion capacity of bacterial suspensions pretreated with antibiotics was done by comparing the adherence/invasion index with controls without antibiotics. Penicillin, amoxicillin with clavulanic acid and vancomycin have significantly stimulated the adherence of Listeria monocytogenes strain and inhibited the adherence of Vibrio cholerae and Aeromonas hydrophyla strains. Ampicillin and chloramphenicole exhibited no significant effect on bacterial adherence capacity. The influence of kanamycin, ceftazidim and norfloxacin could not be interpreted due to the occurrence of a severe cytotoxic effect manifested by cell monolayer detaching, probably due to the action of antibiotic suspensions or to the increase of bacterial virulence under the selective pressure of the

  10. Apa is a trimeric autotransporter adhesin of Actinobacillus pleuropneumoniae responsible for autoagglutination and host cell adherence.

    PubMed

    Xiao, Longwen; Zhou, Liang; Sun, Changjiang; Feng, Xin; Du, ChongTao; Gao, Yu; Ji, Qun; Yang, Shuxin; Wang, Yu; Han, Wenyu; Langford, P R; Lei, Liancheng

    2012-10-01

    Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia, and adherence to host cells is a key step in the pathogenic process. Although trimeric autotransporter adhesins (TAAs) were identified in many pathogenic bacteria in recent years, none in A. pleuropneumoniae have been characterized. In this study, we identified a TAA from A. pleuropneumoniae, Apa, and characterized the contribution of its amino acid residues to the adhesion process. Sequence analysis of the C-terminal amino acid residues of Apa revealed the presence of a putative translocator domain and six conserved HsfBD1-like or HsfBD2-like binding domains. Western blot analysis revealed that the 126 C-terminal amino acids of Apa could form trimeric molecules. By confocal laser scanning microscopy, one of these six domains (ApaBD3) was determined to mediate adherence to epithelial cells. Adherence assays and adherence inhibition assays using a recombinant E. coli- ApaBD3 strain which expressed ApaBD3 on the surface of E. coli confirmed that this domain was responsible for the adhesion activity. Moreover, cellular enzyme-linked immunosorbent assays demonstrated that ApaBD3 mediated high-level adherence to epithelial cell lines. Intriguingly, autoagglutination was observed with the E. coli- ApaBD3 strain, and this phenomenon was dependent upon the association of the expressed ApaBD3 with the C-terminal translocator domain.

  11. Adherence to Antihypertensive Medications in Iranian Patients.

    PubMed

    Behnood-Rod, Azin; Rabbanifar, Omid; Pourzargar, Pirouz; Rai, Alireza; Saadat, Zahra; Saadat, Habibollah; Moharamzad, Yashar; Morisky, Donald E

    2016-01-01

    Introduction. Appropriate adherence to medication is still a challenging issue for hypertensive patients. We determined adherence to antihypertensive(s) and its associated factors among 280 Iranian patients. Methods. They were recruited consecutively from private and university health centers and pharmacies in four cities. The validated Persian version of the 8-item Morisky Medication Adherence Scale (MMAS-8) was administered to measure adherence. Results. Mean (±SD) overall MMAS-8 score was 5.75 (±1.88). About half of the sample (139 cases, 49.6%) showed low adherence (MMAS-8 score < 6). There was a negative linear association between the MMAS-8 score and systolic BP (r = -0.231, P < 0.001) as well as diastolic BP (r = -0.280, P < 0.001). In linear regression model, overweight/obesity (B = -0.52, P = 0.02), previous history of admission to emergency services due to hypertensive crisis (B = -0.79, P = 0.001), and getting medication directly from drugstore without refill prescription in hand (B = -0.51, P = 0.04) were factors recognized to have statistically significant association with the MMAS-8 score. Conclusion. Antihypertensive adherence was unsatisfactory. We suggest that health care providers pay special attention and make use of the aforementioned findings in their routine visits of hypertensive patients to recognize those who are vulnerable to poor adherence. PMID:27069676

  12. [Guideline adherence - is more always better?].

    PubMed

    Nothacker, M J

    2016-09-01

    Guidelines play an increasing role in the health system. Guidelines are intended to provide guidance in the sense of ‟corridors for action and decision", whereby in certain justified cases actions can - or even must - deviate from them. "Cookbook medicine" is not the aim of guidelines.Guideline adherence can not necessarily be equated with guideline conformity. Adherence presumes an agreed treatment goal between patient and physician and focuses the behavior of the patient. Based on current studies on guideline adherence, the use of the term in studies on urological tumors is analyzed.

  13. Participation of Integrin α5β1 in the Fibronectin-Mediated Adherence of Enteroaggregative Escherichia coli to Intestinal Cells

    PubMed Central

    Izquierdo, Mariana; Nataro, James P.; Ruiz-Perez, Fernando; Farfan, Mauricio J.

    2014-01-01

    Adherence to the intestinal epithelia is a key feature in enteroaggregative Escherichia coli (EAEC) infection. The aggregative adherence fimbriae (AAFs) are involved in EAEC interaction with receptors at the surface of intestinal cells. We and others have demonstrated that fibronectin is a receptor for AAF/II fimbriae. Considering that the major cellular receptor of fibronectin is integrin α5β1, in this study we evaluated the participation of this receptor in the fibronectin-mediated adherence of EAEC strain 042 to intestinal cells. We found that EAEC strain 042 has the ability to bind directly and indirectly to integrin α5β1; direct binding was not mediated by AAF/II fimbriae and indirect binding was mediated by AAF/II and fibronectin. Coimmunoprecipitation assays confirmed the formation of the complex AafA/fibronectin/integrin α5β1. To evaluate EAEC adherence to intestinal cells, T84 cells were incubated with fibronectin and an antibody that blocks the interaction region of integrin α5β1 to fibronectin, the RGD site. Under these conditions, we found the number of adherent bacteria to epithelial cells significantly reduced. Additionally, fibronectin-mediated adherence of EAEC strain 042 was abolished in HEp-2 cells transfected with integrin α5 shRNA. Altogether, our data support the involvement of integrin α5β1 in the fibronectin-mediated EAEC binding to intestinal cells. PMID:25177698

  14. Participation of integrin α5β1 in the fibronectin-mediated adherence of enteroaggregative Escherichia coli to intestinal cells.

    PubMed

    Izquierdo, Mariana; Alvestegui, Alejandra; Nataro, James P; Ruiz-Perez, Fernando; Farfan, Mauricio J

    2014-01-01

    Adherence to the intestinal epithelia is a key feature in enteroaggregative Escherichia coli (EAEC) infection. The aggregative adherence fimbriae (AAFs) are involved in EAEC interaction with receptors at the surface of intestinal cells. We and others have demonstrated that fibronectin is a receptor for AAF/II fimbriae. Considering that the major cellular receptor of fibronectin is integrin α5β1, in this study we evaluated the participation of this receptor in the fibronectin-mediated adherence of EAEC strain 042 to intestinal cells. We found that EAEC strain 042 has the ability to bind directly and indirectly to integrin α5β1; direct binding was not mediated by AAF/II fimbriae and indirect binding was mediated by AAF/II and fibronectin. Coimmunoprecipitation assays confirmed the formation of the complex AafA/fibronectin/integrin α5β1. To evaluate EAEC adherence to intestinal cells, T84 cells were incubated with fibronectin and an antibody that blocks the interaction region of integrin α5β1 to fibronectin, the RGD site. Under these conditions, we found the number of adherent bacteria to epithelial cells significantly reduced. Additionally, fibronectin-mediated adherence of EAEC strain 042 was abolished in HEp-2 cells transfected with integrin α5 shRNA. Altogether, our data support the involvement of integrin α5β1 in the fibronectin-mediated EAEC binding to intestinal cells.

  15. Participation of integrin α5β1 in the fibronectin-mediated adherence of enteroaggregative Escherichia coli to intestinal cells.

    PubMed

    Izquierdo, Mariana; Alvestegui, Alejandra; Nataro, James P; Ruiz-Perez, Fernando; Farfan, Mauricio J

    2014-01-01

    Adherence to the intestinal epithelia is a key feature in enteroaggregative Escherichia coli (EAEC) infection. The aggregative adherence fimbriae (AAFs) are involved in EAEC interaction with receptors at the surface of intestinal cells. We and others have demonstrated that fibronectin is a receptor for AAF/II fimbriae. Considering that the major cellular receptor of fibronectin is integrin α5β1, in this study we evaluated the participation of this receptor in the fibronectin-mediated adherence of EAEC strain 042 to intestinal cells. We found that EAEC strain 042 has the ability to bind directly and indirectly to integrin α5β1; direct binding was not mediated by AAF/II fimbriae and indirect binding was mediated by AAF/II and fibronectin. Coimmunoprecipitation assays confirmed the formation of the complex AafA/fibronectin/integrin α5β1. To evaluate EAEC adherence to intestinal cells, T84 cells were incubated with fibronectin and an antibody that blocks the interaction region of integrin α5β1 to fibronectin, the RGD site. Under these conditions, we found the number of adherent bacteria to epithelial cells significantly reduced. Additionally, fibronectin-mediated adherence of EAEC strain 042 was abolished in HEp-2 cells transfected with integrin α5 shRNA. Altogether, our data support the involvement of integrin α5β1 in the fibronectin-mediated EAEC binding to intestinal cells. PMID:25177698

  16. Embedding silica and polymer fibre Bragg gratings (FBG) in plastic 3D-printed sensing patches

    NASA Astrophysics Data System (ADS)

    Zubel, Michal G.; Sugden, Kate; Webb, David J.; Sáez-Rodríguez, David; Nielsen, Kristian; Bang, Ole

    2016-04-01

    This paper reports the first demonstration of a silica fibre Bragg grating (SOFBG) embedded in an FDM 3-D printed housing to yield a dual grating temperature-compensated strain sensor. We also report the first ever integration of polymer fibre Bragg grating (POFBG) within a 3-D printed sensing patch for strain or temperature sensing. The cyclic strain performance and temperature characteristics of both devices are examined and discussed. The strain sensitivities of the sensing patches were 0.40 and 0.95 pm/μɛ for SOFBG embedded in ABS, 0.38 pm/μɛ for POFBG in PLA, and 0.15 pm/μɛ for POFBG in ABS. The strain response was linear above a threshold and repeatable. The temperature sensitivity of the SOFBG sensing patch was found to be up to 169 pm/°C, which was up to 17 times higher than for an unembedded silica grating. Unstable temperature response POFBG embedded in PLA was reported, with temperature sensitivity values varying between 30 and 40 pm/°C.

  17. Effect of Temperature on Fimbrial Gene Expression and Adherence of Enteroaggregative Escherichia coli.

    PubMed

    Hinthong, Woranich; Indrawattana, Nitaya; Pitaksajjakul, Pannamthip; Pipattanaboon, Chonlatip; Kongngoen, Thida; Tharnpoophasiam, Prapin; Worakhunpiset, Suwalee

    2015-08-01

    The influence of temperature on bacterial virulence has been studied worldwide from the viewpoint of climate change and global warming. The bacterium enteroaggregative Escherichia coli (EAEC) is the causative agent of watery diarrhea and shows an increasing incidence worldwide. Its pathogenicity is associated with the virulence factors aggregative adherence fimbria type I and II (AAFI and AAFII), encoded by aggA and aafA in EAEC strains 17-2 and 042, respectively. This study focused on the effect of temperature increases from 29 °C to 40 °C on fimbrial gene expression using real-time PCR, and on its virulence using an aggregative adherence assay and biofilm formation assay. Incubation at 32 °C caused an up-regulation in both EAEC strains 17-2 and strain 042 virulence gene expression. EAEC strain 042 cultured at temperature above 32 °C showed down-regulation of aafA expression except at 38 °C. Interestingly, EAEC cultured at a high temperature showed a reduced adherence to cells and an uneven biofilm formation. These results provide evidence that increases in temperature potentially affect the virulence of pathogenic EAEC, although the response varies in each strain. PMID:26213951

  18. Effect of Temperature on Fimbrial Gene Expression and Adherence of Enteroaggregative Escherichia coli.

    PubMed

    Hinthong, Woranich; Indrawattana, Nitaya; Pitaksajjakul, Pannamthip; Pipattanaboon, Chonlatip; Kongngoen, Thida; Tharnpoophasiam, Prapin; Worakhunpiset, Suwalee

    2015-08-01

    The influence of temperature on bacterial virulence has been studied worldwide from the viewpoint of climate change and global warming. The bacterium enteroaggregative Escherichia coli (EAEC) is the causative agent of watery diarrhea and shows an increasing incidence worldwide. Its pathogenicity is associated with the virulence factors aggregative adherence fimbria type I and II (AAFI and AAFII), encoded by aggA and aafA in EAEC strains 17-2 and 042, respectively. This study focused on the effect of temperature increases from 29 °C to 40 °C on fimbrial gene expression using real-time PCR, and on its virulence using an aggregative adherence assay and biofilm formation assay. Incubation at 32 °C caused an up-regulation in both EAEC strains 17-2 and strain 042 virulence gene expression. EAEC strain 042 cultured at temperature above 32 °C showed down-regulation of aafA expression except at 38 °C. Interestingly, EAEC cultured at a high temperature showed a reduced adherence to cells and an uneven biofilm formation. These results provide evidence that increases in temperature potentially affect the virulence of pathogenic EAEC, although the response varies in each strain.

  19. Analysis of temperature and strain sensitivity of fiber Bragg gratings written in dual-mode highly birefringent microstructured fibers

    NASA Astrophysics Data System (ADS)

    Tenderenda, T.; Murawski, M.; Szymanski, M.; Becker, M.; Rothhardt, M.; Bartelt, H.; Mergo, P.; Poturaj, K.; Makara, M.; Skorupski, K.; Marc, P.; Jaroszewicz, L. R.; Nasilowski, T.

    2013-05-01

    Fiber Bragg gratings (FBG) are one of the most successful fiber optic technologies with very interesting perspectives for application in fiber optic sensing. It has been already reported that the possibility of its fabrication in novel microstructured fibers (MSF), creating a unique 3D structure, can significantly improve their performance and sensing properties. In this paper we present the results of FBG inscription in a dual-mode highly birefringent (HB) MSF with enhanced polarimetric strain sensitivity of the second order mode, as its mode maxima are closer to the cladding air-holes, where the strain distribution during fiber elongation is the highest. We perform an analysis and comparison of the FBG reflection and transmission characteristics, showing the effects of power coupling to cladding radiation modes. Furthermore we present the results of temperature and longitudinal strain sensitivities of the particular modes visible in the grating reflection spectrum followed by conclusions with reference to our previously reported results of polarimetric strain and temperature measurements of a similar fiber design.

  20. Medication adherence behaviors of Medicare beneficiaries

    PubMed Central

    Carr-Lopez, Sian M; Shek, Allen; Lastimosa, Janine; Patel, Rajul A; Woelfel, Joseph A; Galal, Suzanne M; Gundersen, Berit

    2014-01-01

    Background Medication adherence is crucial for positive outcomes in the management of chronic conditions. Comprehensive medication consultation can improve medication adherence by addressing intentional and unintentional nonadherence. The Medicare Part D prescription drug benefit has eliminated some cost barriers. We sought to examine variables that impact self-reported medication adherence behaviors in an ambulatory Medicare-beneficiary population and to identify the factors that influence what information is provided during a pharmacist consultation. Methods Medicare beneficiaries who attended health fairs in northern California were offered medication therapy management (MTM) services during which demographic, social, and health information, and responses to survey questions regarding adherence were collected. Beneficiaries were also asked which critical elements of a consultation were typically provided by their community pharmacist. Survey responses were examined as a function of demographic, socioeconomic, and health-related factors. Results Of the 586 beneficiaries who were provided MTM services, 575 (98%) completed the adherence questions. Of responders, 406 (70%) reported taking medications “all of the time”. Of the remaining 169 (30%), the following reasons for nonadherence were provided: 123 (73%) forgetfulness; 18 (11%) side effects; and 17 (10%) the medication was not needed. Lower adherence rates were associated with difficulty paying for medication, presence of a medication-related problem, and certain symptomatic chronic conditions. Of the 532 who completed survey questions regarding the content of a typical pharmacist consultation, the topics included: 378 (71%) medication name and indication; 361 (68%) administration instructions; 307 (58%) side effects; 257 (48%) missed-dose instructions; and 245 (46%) interactions. Subsidy recipients and non-English speakers were significantly less likely to be counseled on drug name, indication, and side

  1. Bayesian population modeling of drug dosing adherence.

    PubMed

    Fellows, Kelly; Stoneking, Colin J; Ramanathan, Murali

    2015-10-01

    Adherence is a frequent contributing factor to variations in drug concentrations and efficacy. The purpose of this work was to develop an integrated population model to describe variation in adherence, dose-timing deviations, overdosing and persistence to dosing regimens. The hybrid Markov chain-von Mises method for modeling adherence in individual subjects was extended to the population setting using a Bayesian approach. Four integrated population models for overall adherence, the two-state Markov chain transition parameters, dose-timing deviations, overdosing and persistence were formulated and critically compared. The Markov chain-Monte Carlo algorithm was used for identifying distribution parameters and for simulations. The model was challenged with medication event monitoring system data for 207 hypertension patients. The four Bayesian models demonstrated good mixing and convergence characteristics. The distributions of adherence, dose-timing deviations, overdosing and persistence were markedly non-normal and diverse. The models varied in complexity and the method used to incorporate inter-dependence with the preceding dose in the two-state Markov chain. The model that incorporated a cooperativity term for inter-dependence and a hyperbolic parameterization of the transition matrix probabilities was identified as the preferred model over the alternatives. The simulated probability densities from the model satisfactorily fit the observed probability distributions of adherence, dose-timing deviations, overdosing and persistence parameters in the sample patients. The model also adequately described the median and observed quartiles for these parameters. The Bayesian model for adherence provides a parsimonious, yet integrated, description of adherence in populations. It may find potential applications in clinical trial simulations and pharmacokinetic-pharmacodynamic modeling. PMID:26319548

  2. Adherence of Staphylococcus epidermidis to intraocular lenses.

    PubMed Central

    Griffiths, P. G.; Elliot, T. S.; McTaggart, L.

    1989-01-01

    We have demonstrated, with an in vitro model, that Staphylococcus epidermidis is able to colonise intraocular lenses. Adherent organisms were quantitated by light microscopy, scanning electron microscopy, and viable counting. Bacterial adherence was associated with production of a polysaccharide glycocalyx. Organisms which were attached to the lenses were resistant to apparently bactericidal concentrations of antibiotics, as determined by conventional testing. We speculate on the role of colonisation in the pathogenesis of endophthalmitis. Images PMID:2751971

  3. Novel aggregative adherence fimbria variant of enteroaggregative Escherichia coli.

    PubMed

    Jønsson, Rie; Struve, Carsten; Boisen, Nadia; Mateiu, Ramona Valentina; Santiago, Araceli E; Jenssen, Håvard; Nataro, James P; Krogfelt, Karen A

    2015-04-01

    Enteroaggregative Escherichia coli (EAEC) organisms belong to a diarrheagenic pathotype known to cause diarrhea and can be characterized by distinct aggregative adherence (AA) in a stacked-brick pattern to cultured epithelial cells. In this study, we investigated 118 EAEC strains isolated from the stools of Danish adults with traveler's diarrhea. We evaluated the presence of the aggregative adherence fimbriae (AAFs) by a multiplex PCR, targeting the four known major subunit variants as well as their usher-encoding genes. Almost one-half (49/118) of the clinical isolates did not possess any known AAF major fimbrial subunit, despite the presence of other AggR-related loci. Further investigation revealed the presence of an AAF-related gene encoding a yet-uncharacterized adhesin, termed agg5A. The sequence of the agg5DCBA gene cluster shared fimbrial accessory genes (usher, chaperone, and minor pilin subunit genes) with AAF/III, as well as the signal peptide present in the beginning of the agg3A gene. The complete agg5DCBA gene cluster from a clinical isolate, EAEC strain C338-14, with the typical stacked-brick binding pattern was cloned, and deletion of the cluster was performed. Transformation to a nonadherent E. coli HB101 and complementation of the nonadherent C338-14 mutant with the complete gene cluster restored the AA adhesion. Overall, we found the agg5A gene in 12% of the 118 strains isolated from Denmark, suggesting that this novel adhesin represents an important variant.

  4. Emerging technologies for electronic monitoring of adherence, inhaler competence, and true adherence.

    PubMed

    Pritchard, John N; Nicholls, Clare

    2015-04-01

    Despite the availability of effective treatments for respiratory disorders, disease control is often suboptimal, due in part to the failure of patients to adhere to prescribed regimens, or to demonstrate competence with the often complex steps in the administration of inhaled medications. The cost of poor true adherence, a combined measure of adherence and inhaler competence, is considerable, both economically and in terms of health-related impact. While patient education is recognized as essential, there exist many barriers to healthcare professional-led monitoring and promotion of true adherence. Successful intervention remains a challenging task, dependent upon understanding and addressing the distinct issues associated with poor adherence and inhaler competence, and lessening the perceived burden on healthcare professionals. Electronic monitors provide an accurate and objective indication of adherence and may also be of value in assessing inhaler competence. The information provided by such devices is a helpful aid to understanding the challenging nature of true adherence, and may be crucial to the development and assessment of true adherence promoting interventions. This article provides a background to the impact of suboptimal adherence and inhaler competence, and the challenges associated with the promotion of true adherence, with an emphasis on respiratory therapies. Contemporary electronic monitors of adherence and inhaler competence are critically reviewed, and case studies of emerging technologies are provided to illustrate the use of innovative monitoring devices in the promotion of true adherence in practice. Potential future directions, including increased targeting and individualization, enhanced coordination of care, and a greater focus on inhaler competence are considered to be important additions to currently available technologies in this rapidly evolving field.

  5. Interventions to increase adherence to acne treatment

    PubMed Central

    Moradi Tuchayi, Sara; Alexander, Tiffany M; Nadkarni, Anish; Feldman, Steven R

    2016-01-01

    Background Adherence to acne medication is poor and is a major reason why treatment plans are ineffective. Recognizing solutions to nonadherence is critical. Objective The purpose of this study is to describe the hurdles associated with acne nonadherence and to provide mechanisms on how to ameliorate them. Methods PubMed database was searched. Of the 419 search results, 29 articles were reviewed to identify hurdles to adherence and corresponding solutions. Results Hurdles to primary nonadherence where the medication is not even started, include lack of knowledge, confusion about usage, weak physician–patient relationship, fear of adverse reactions, and cost. Secondary nonadherence hurdles where the medication is started but is not taken as directed include lack of results, complex regimens, side effects, busy lifestyle, forgetfulness, inconvenience, and psychiatric comorbidity. Solutions to these hurdles include treatment simplification, technology, and dynamic education. Limitations Adherence is affected by numerous factors, but available literature analyzing acne adherence and interventions to improve adherence to treatment is limited. Conclusion There are several hurdles in adhering to acne treatment. Recognition of these hurdles and finding appropriate solutions may be as important to treatment outcomes as choosing the right medication to prescribe. PMID:27784999

  6. Patient Perceptions of Voice Therapy Adherence

    PubMed Central

    van Leer, Eva; Connor, Nadine P.

    2009-01-01

    Purpose Patient perspectives of behavioral voice therapy, including perspectives of treatment adherence, have not been formally documented. Because treatment adherence is to a large extent determined by patient beliefs, assessment of patient perspectives is integral to the study of adherence. Methods Fifteen patients who had undergone at least 2 sessions of direct voice therapy for a variety of voice disorders/complaints were interviewed about their perspectives on voice therapy, with a particular focus on adherence. Interviews were transcribed and analyzed for content according to qualitative methods. Results Three common content themes emerged from the transcripts: Voice Therapy is Hard, Make it Happen, and The Match Matters. Findings are compared to reports of patient experiences in other behavioral interventions such as diet and exercise, and related to existing theoretical models of behavior change and the therapeutic process. Conclusion This study yields information toward the development of scales to measure adherence-related constructs and strategies to improve treatment adherence in voice therapy. PMID:19775866

  7. Patient Education and Adherence to Aerosol Therapy.

    PubMed

    Ari, Arzu

    2015-06-01

    Nonadherence to prescribed medications results in disease instability and poor clinical control, with increases in hospital admissions, emergency room visits, school/work absenteeism, morbidity, and mortality. Poor patient adherence to therapy can be due to lack of cognition, competence, or contrivance. Patients who have not been trained or fail to understand use of drug and device combinations (cognition) often do not have the ability to use an aerosol device correctly (competence). Many patients have the competence to use the device correctly and know why they should use the device in the way they were taught; however, they still contrive to use it in an ineffective and suboptimal manner that reduces its efficiency and effectiveness. Ensuring effective aerosol therapy and optimizing its role in disease management involve not only delivery of aerosolized medications to the lungs, but also understanding why, when, and how to use the medications, competence to use the device, motivation to adhere to therapy, and not contriving to use the device in a way that will prevent effective drug delivery. This paper explains some of the problems with patient education and adherence to aerosol therapy and suggests strategies to evaluate, monitor, and improve patient adherence effectively in primary care. Factors affecting patient adherence to prescribed medications, effective educational interventions, and strategies to promote patient adherence to aerosol therapy are also discussed.

  8. Research of weapon equipments health monitoring based on FBG intelligent composite materials

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-li; Fu, Zhu-lin; Zhao, Bing; Xu, Jian-guo

    2010-10-01

    Embedding the Polymer fibers, whose limiting strain is about 10%, into the composite materials to form the intelligent materials is researched. Encapsulating polymer fibers with epoxy resin of identical elastic modulus and embedding them into the structures during the molding process. The Demodulating system based on F-P filter method is advanced to analyze the shift of wavelengths with high speed DSP TMSC3206713 as data processor. Precise PIN photoelectric cell-InGaAs-PIN-PD753, is used to transform the output of F-P filter to electricity and two high speed A/D chips ADS1610 are used to collect the outputs of PINs. C2H2 GC for dynamical wavelength demarcation is advanced for more precise metrical results. Strain and damage condition information is transferred to the master computer as the references of health monitoring of weapon equipments. The primary experiments indicate that when 2 fibers with 3 gratings on each are embedded into the material, the intensity of materials don't weaken obviously. During the molding process of high temperature and high pressure, reflected spectrum of FBGs in hot stretching environment is analyzed through Spectrum Instrument. Fibers do not be ruptured and their sensitivity of strain is well. F-P demodulating system realizes strain resolution by 2μɛ when it works at 200Hz.

  9. A highly adherent phenotype associated with virulent Bvg+-phase swine isolates of Bordetella bronchiseptica grown under modulating conditions.

    PubMed Central

    Register, K B; Ackermann, M R

    1997-01-01

    The ability of Bvg(-)-phase and Bvg(+)-phase Bordetella bronchiseptica swine isolates, grown under modulating or nonmodulating conditions, to adhere to swine ciliated nasal epithelial cells was determined. When virulent strains were cultivated at 37 degrees C in the Bvg+ phase, numerous adherent bacteria (approximately eight per cell, depending on the strain used) were observed. However, when such strains were grown under modulating conditions (23 degrees C), a significant increase in the level of attachment was seen, suggesting that B. bronchiseptica produces a Bvg-repressed adhesin under these conditions. bvg mutant strains, including an isogenic bvgS mutant, adhered minimally. Western blots indicated that two putative B. bronchiseptica adhesins, filamentous hemagglutinin and pertactin, were not detectable in cultures displaying the highly adherent phenotype. Several proteins apparent in Western blots obtained by using bacterial extracts enriched in outer membrane proteins derived from B. bronchiseptica grown at 23 degrees C were not present in similar extracts prepared from an isogenic bvgS mutant grown at 23 degrees C or from the parent strain grown at 37 degrees C. Adherence of bacteria cultivated at 23 degrees C was almost completely abolished by pretreatment of organisms at 60 degrees C; adherence was reduced by 57% when bacteria were pretreated with pronase E. Temperature shift experiments revealed that the heightened level of adhesion that occurs following growth at 23 degrees C was maintained for up to 18 h when bacteria were subsequently incubated at 37 degrees C. We propose that a Bvg-repressed adhesin, expressed only by modulated bvg+ strains of B. bronchiseptica, may play a key role in the initial colonization of naturally infected swine. PMID:9393829

  10. Effect of the location and size of a single crack on first fundamental frequency of a cantilever beam using fiber optic polarimetric sensors and characterisation of FBG sensors

    NASA Astrophysics Data System (ADS)

    Maheshwari, Muneesh; Asundi, A. K.; Tjin, Swee C.

    2013-08-01

    Fiber Optics Polarimetric Sensors (FOPS), utilizing first fundamental frequency mode and its harmonics, have already been used as damage detection tool. The FOPS technology is attractive in damage detection as it facilitates us with real time non-destructive health monitoring of different mechanical and civil structures. In this paper, the effects of the size and the location of a single crack on the frequency of first fundamental mode of a cantilever beam have been studied. A relation between the relative size of a crack and relative change in the first fundamental frequency has been established theoretically and then verified experimentally. Further, it has been shown that the cracks, close to the fixed end of the cantilever beam, have significant effect on the frequency of first fundamental mode and as the crack moves away from the fixed end, the effect on the frequency starts becoming diminished. Also the sensitivity of Fiber Bragg Grating (FBG) sensor against a single crack has been studied along both the directions; parallel to the axis of FBG sensor and perpendicular to the axis of FBG sensor. Experimental results show that the range of sensitivity in both the directions is almost the same bur FBG is more efficient along its axis.

  11. Selective adherence of non-typeable Haemophilus influenzae (NTHi) to mucus or epithelial cells in the chinchilla eustachian tube and middle ear.

    PubMed

    Miyamoto, N; Bakaletz, L O

    1996-11-01

    Frozen sections of chinchilla Eustachian tube (ET) and middle ear mucosa were incubated with either FITC-labeled non-typeable Haemophilus influenzae (NTHi) or Bordetella pertussis. The number of bacteria adherent to "roof" vs "floor" regions was compared for each of three anatomic portions of the ET and for middle ear epithelium noting whether bacteria adhered to mucus or to epithelial cells. NTHi strains adhered significantly greater to mucus in the ET lumen whereas B. pertussis preferentially adhered to epithelial cells lining the ET (P < or = 0.05). A non-fimbriated isogenic mutant of NTHi adhered significantly less to mucus than the parental isolate at all sites of the ET floor (P < or = 0.05). Isolated fimbrin protein adhered to ET mucus and blocked adherence of whole organisms. Treatment with the mucolytic agent N-acetyl-L-cysteine resulted in significantly reduced adherence of NTHi to mucus (P < or = 0.001) and eliminated the ability to detect binding of isolated fimbrin protein. N-acetyl-L-cysteine treatment did not affect adherence of either B. pertussis or NTHi to epithelial cells. These data indicated that NTHi may mediate ascension of the ET from the nasopharynx primarily via adherence to and growth in mucus overlying the floor region of the tubal lumen. The OMP P5-homologous fimbriae were shown to contribute to this binding.

  12. Power-stabilized tunable narrow-band source using a VCSEL and an EDFA for FBG sensor interrogation

    NASA Astrophysics Data System (ADS)

    Mizunami, Toru; Hirose, Shuji; Yoshinaga, Takeshi; Yamamoto, Ken-ichi

    2013-09-01

    Wavelength tuning with a current of a long-wavelength vertical-cavity surface-emitting laser (VCSEL) was studied for application to wavelength readout of fiber Bragg grating (FBG) sensors. 1.5 µm single-longitudinal-mode VCSELs with a spectral line width of 30 MHz were used. To decrease the variation in the output power with the current, saturated amplification of the VCSEL output by an erbium-doped fiber amplifier (EDFA) was proposed. In the experiment, the wavelength readout of an FBG by variation in the VCSEL current was studied first, and then amplification characteristics using a commercially available EDFA module were measured. Two VCSELs with different wavelengths and tuning ranges were used as input and compared. For a VCSEL with a wavelength tuning range of 2.5 nm, there was a threefold change in the VCSEL output power. However, the variation in the amplified output power was within ±14%. For another VCSEL with a wavelength tuning range of 3.9 nm, the variation in the amplified output power was within ±18% for variation in the VCSEL output power by 2.2 times. The power slope with respect to the wavelength was also decreased by the stabilization. Computer simulation was performed to study the wavelength shift in the measured Bragg wavelength induced by the power slope. The simulation showed that the wavelength shift can be reduced to 1/2.5-1/5 by the stabilization compared with that using a single VCSEL. Application to long-period grating sensors was also discussed.

  13. Weight loss intervention adherence and factors promoting adherence: a meta-analysis

    PubMed Central

    Lemstra, Mark; Bird, Yelena; Nwankwo, Chijioke; Rogers, Marla; Moraros, John

    2016-01-01

    Background Adhering to weight loss interventions is difficult for many people. The majority of those who are overweight or obese and attempt to lose weight are simply not successful. The objectives of this study were 1) to quantify overall adherence rates for various weight loss interventions and 2) to provide pooled estimates for factors associated with improved adherence to weight loss interventions. Methods We performed a systematic literature review and meta-analysis of all studies published between January 2004 and August 2015 that reviewed weight loss intervention adherence. Results After applying inclusion and exclusion criteria and checking the methodological quality, 27 studies were included in the meta-analysis. The overall adherence rate was 60.5% (95% confidence interval [CI] 53.6–67.2). The following three main variables were found to impact adherence: 1) supervised attendance programs had higher adherence rates than those with no supervision (rate ratio [RR] 1.65; 95% CI 1.54–1.77); 2) interventions that offered social support had higher adherence than those without social support (RR 1.29; 95% CI 1.24–1.34); and 3) dietary intervention alone had higher adherence than exercise programs alone (RR 1.27; 95% CI 1.19–1.35). Conclusion A substantial proportion of people do not adhere to weight loss interventions. Programs supervising attendance, offering social support, and focusing on dietary modification have better adherence than interventions not supervising attendance, not offering social support, and focusing exclusively on exercise. PMID:27574404

  14. Fiber Bragg Gratings, IT Techniques and Strain Gauge Validation for Strain Calculation on Aged Metal Specimens

    PubMed Central

    Montero, Ander; de Ocariz, Idurre Saez; Lopez, Ion; Venegas, Pablo; Gomez, Javier; Zubia, Joseba

    2011-01-01

    This paper studies the feasibility of calculating strains in aged F114 steel specimens with Fiber Bragg Grating (FBG) sensors and infrared thermography (IT) techniques. Two specimens have been conditioned under extreme temperature and relative humidity conditions making comparative tests of stress before and after aging using different adhesives. Moreover, a comparison has been made with IT techniques and conventional methods for calculating stresses in F114 steel. Implementation of Structural Health Monitoring techniques on real aircraft during their life cycle requires a study of the behaviour of FBG sensors and their wiring under real conditions, before using them for a long time. To simulate aging, specimens were stored in a climate chamber at 70 °C and 90% RH for 60 days. This study is framed within the Structural Health Monitoring (SHM) and Non Destructuve Evaluation (NDE) research lines, integrated into the avionics area maintained by the Aeronautical Technologies Centre (CTA) and the University of the Basque Country (UPV/EHU). PMID:22346619

  15. Optomechanical behavior of embedded fiber Bragg grating strain sensors

    NASA Astrophysics Data System (ADS)

    Mastro, Stephen A.

    2005-11-01

    Fiber Bragg gratings (FBGs) can provide extremely sensitive strain measurements for various materials and structures. The main functionality of the Bragg grating is along the fiber's main axis, where changes in the grating's spacing can be converted into strain measurements. Previous work from a number of researchers has identified bifurcation and broadening of the Bragg signal under transverse loading. The work presented in this thesis highlights efforts to relate transverse loading to changes in index of refraction in the fiber core cross section, and then ultimately to predicted changes in Bragg signals. The background of FBGs, their application, manufacturing, and operation is outlined. In addition, background on the general concept of photoelasticity, the relationship of stress and index of refraction, in glass materials is presented. A theoretical analysis was performed for uncoated silica fiber to calculate the stresses within an optical fiber core under transverse loading. The transverse loading profile ranged from pure diametric point loading to a more distributed profile. The stresses calculated were translated into changes of index of refraction and FBG signal values. The analysis was then simulated utilizing a numerical model, calculating stress, change of index of refraction, and change in FBG signal with various transverse loading profiles. In addition to an uncoated fiber, a polymer coated fiber system was analyzed. The model was verified by performing a laboratory experiment where FBGs were loaded transversely and their signal monitored. A special loading rig was designed and fabricated to impart transverse loading to the fiber while monitoring the compression load and deflection of the loading plates. The laboratory experienced showed reasonable agreement with the numerical model. The data show that side loading of the FBG caused a bifurcation of the signal, and that this effect can be predicted by the theoretical model. The modeling work completed

  16. Flagellar Cap Protein FliD Mediates Adherence of Atypical Enteropathogenic Escherichia coli to Enterocyte Microvilli.

    PubMed

    Sampaio, Suely C F; Luiz, Wilson B; Vieira, Mônica A M; Ferreira, Rita C C; Garcia, Bruna G; Sinigaglia-Coimbra, Rita; Sampaio, Jorge L M; Ferreira, Luís C S; Gomes, Tânia A T

    2016-04-01

    The expression of flagella correlates with different aspects of bacterial pathogenicity, ranging from adherence to host cells to activation of inflammatory responses by the innate immune system. In the present study, we investigated the role of flagella in the adherence of an atypical enteropathogenic Escherichia coli (aEPEC) strain (serotype O51:H40) to human enterocytes. Accordingly, isogenic mutants deficient in flagellin (FliC), the flagellar structural subunit; the flagellar cap protein (FliD); or the MotAB proteins, involved in the control of flagellar motion, were generated and tested for binding to differentiated Caco-2 cells. Binding of the aEPEC strain to enterocytes was significantly impaired in strains with the fliCa nd fliD genes deleted, both of which could not form flagella on the bacterial surface. A nonmotile but flagellated MotAB mutant also showed impaired adhesion to Caco-2 cells. In accordance with these observations, adhesion of a EPEC strain 1711-4 to Caco-2 cells was drastically reduced after the treatment of Caco-2 cells with purified FliD. In addition, incubation of a EPEC bacteria with specific anti-FliD serum impaired binding to Caco-2 cells. Finally, incubation of Caco-2 cells with purified FliD, followed by immunolabeling, showed that the protein was specifically bound to the microvillus tips of differentiated Caco-2 cells. The a EPEC FliD or anti-FliD serum also reduced the adherence of prototype typical enteropathogenic, enterohemorrhagic, and enterotoxigenic E. coli strains to Caco-2 cells. In conclusion, our findings further strengthened the role of flagella in the adherence of a EPEC to human enterocytes and disclosed the relevant structural and functional involvement of FliD in the adhesion process. PMID:26831466

  17. Flagellar Cap Protein FliD Mediates Adherence of Atypical Enteropathogenic Escherichia coli to Enterocyte Microvilli

    PubMed Central

    Sampaio, Suely C. F.; Luiz, Wilson B.; Vieira, Mônica A. M.; Ferreira, Rita C. C.; Garcia, Bruna G.; Sinigaglia-Coimbra, Rita; Sampaio, Jorge L. M.; Ferreira, Luís C. S.

    2016-01-01

    The expression of flagella correlates with different aspects of bacterial pathogenicity, ranging from adherence to host cells to activation of inflammatory responses by the innate immune system. In the present study, we investigated the role of flagella in the adherence of an atypical enteropathogenic Escherichia coli (aEPEC) strain (serotype O51:H40) to human enterocytes. Accordingly, isogenic mutants deficient in flagellin (FliC), the flagellar structural subunit; the flagellar cap protein (FliD); or the MotAB proteins, involved in the control of flagellar motion, were generated and tested for binding to differentiated Caco-2 cells. Binding of the aEPEC strain to enterocytes was significantly impaired in strains with the fliC and fliD genes deleted, both of which could not form flagella on the bacterial surface. A nonmotile but flagellated MotAB mutant also showed impaired adhesion to Caco-2 cells. In accordance with these observations, adhesion of aEPEC strain 1711-4 to Caco-2 cells was drastically reduced after the treatment of Caco-2 cells with purified FliD. In addition, incubation of aEPEC bacteria with specific anti-FliD serum impaired binding to Caco-2 cells. Finally, incubation of Caco-2 cells with purified FliD, followed by immunolabeling, showed that the protein was specifically bound to the microvillus tips of differentiated Caco-2 cells. The aEPEC FliD or anti-FliD serum also reduced the adherence of prototype typical enteropathogenic, enterohemorrhagic, and enterotoxigenic E. coli strains to Caco-2 cells. In conclusion, our findings further strengthened the role of flagella in the adherence of aEPEC to human enterocytes and disclosed the relevant structural and functional involvement of FliD in the adhesion process. PMID:26831466

  18. Role of Adherence in the Pathogenesis of Pseudomonas aeruginosa Lung Infection in Cystic Fibrosis Patients

    PubMed Central

    Woods, Donald E.; Bass, Joe A.; Johanson, W. G.; Straus, David C.

    1980-01-01

    A correlation has been demonstrated between the in vitro adherence of Pseudomonas aeruginosa to upper respiratory tract epithelium and colonization of the respiratory tract by this organism. Twenty patients with cystic fibrosis (CF) and 20 age-matched controls were examined in this study. All of the CF patients but none of the controls were colonized with P. aeruginosa at the time of study. P. aeruginosa adherence to isolated epithelial cells, as determined by an in vitro assay, was 19.1 ± 1.1 bacteria per buccal epithelial cell in the CF patients and 2.3 ± 0.3 bacteria per cell in the controls (P < 0.01). P. aeruginosa strains of the mucoid colony type adhered in significantly lower numbers to buccal epithelial cells than did strains of the rough colony type (1.8 + 0.1 versus 24.8 ± 0.9, P < 0.001). This difference might explain the common observation that the initial pseudomonas colonization of the respiratory tract of CF patients is due to organisms of the rough colony type. We have further demonstrated that increased P. aeruginosa adherence in vitro varies directly with the loss of a protease-sensitive glycoprotein, fibronectin, from the cell surface, as well as increased levels of salivary proteases in CF patients. When examined by a direct radioimmune binding assay, buccal cells from CF patients possessed only 17% of the total cell surface fibronectin present on similar cells obtained from controls. Salivary protease levels, as measured by 125I release from an 125I-labeled insoluble fibrin matrix, were increased about threefold in CF patients versus controls. Thus, colonization of the respiratory tract by P. aeruginosa in CF patients correlates well with buccal cell adherence of this organism; increased adherence is associated with decreased amounts of fibronectin on respiratory epithelial cell surfaces and increased levels of salivary proteases. PMID:7014444

  19. Realization of nano static strain sensing with fiber Bragg gratings interrogated by narrow linewidth tunable lasers.

    PubMed

    Liu, Qingwen; Tokunaga, Tomochika; He, Zuyuan

    2011-10-10

    Aiming at realizing a static strain sensor of nano-strain resolution, which is required in most geophysical applications, this paper presents a thorough analysis on the strain resolution of a fiber Bragg grating (FBG) static strain sensor interrogated with a narrow linewidth tunable laser. The main noise sources of the sensor are discussed, and the strain resolution is deduced with a cross-correlation algorithm. The theoretical prediction agrees well with our experimental result, and the analysis is further validated by numerical simulations. Based on the analysis, the paper provides the guidelines for optimizing this type of sensor to realize ultra-high resolution. It is shown that with properly designed FBGs and interrogation systems, nano static strain resolution can be realized, as we recently demonstrated in experiment.

  20. Assessing adherence factors in patients under topical treatment: development of the Topical Therapy Adherence Questionnaire (TTAQ).

    PubMed

    Zschocke, Ina; Mrowietz, Ulrich; Lotzin, Annett; Karakasili, Eleni; Reich, Kristian

    2014-04-01

    Medication adherence rates strongly depend on favorable disease outcomes. It is known that medication adherence rates are lower for topical treatment than for systemic treatment. However, to date no validated instrument for the assessment of adherence factors in topical treatment is available. The aim of this study was to develop a new questionnaire to assess adherence risk factors in topical treatment. The development of the Topical Therapy Adherence Questionnaire (TTAQ) and Patient Preference Questionnaire (PPQ) was based on a systematic literature review, and qualitative patient focus interviews and expert focus groups' input. The psychometric properties and comprehensibility of the TTAQ and PPQ were assessed in a feasibility study with 59 psoriasis patients. Our first preliminary results indicate that the TTAQ and PPQ are psychometrically sound and reliable measures for the assessment of factors influencing topical treatment adherence. The questionnaires are currently being further developed and various parameters (e.g., time point of assessment) are currently being tested in an exploratory pilot study with ca. 2,000 psoriasis patients receiving topical treatment in a European clinical trial. The use of the final versions of TTAQ and PPQ in clinical practice may facilitate the early identification of specific non-adherence factors in patients under topical treatment, which could enable designing and applying adherence-enhancing interventions according to the patient's individual needs.

  1. Simultaneous measurement of dynamic displacement and strain in a single fiber using coarse wavelength-division multiplexing and fiber Bragg-grating filter-based sensing system.

    PubMed

    Chuang, Kuo-Chih; Ma, Chien-Ching; Wang, Hwa-Chun

    2016-03-20

    Displacement and strain, two of the most important physical quantities in experimental solid mechanics, are seldomly measured simultaneously in a single experimental configuration. In order to provide and improve corresponding sensing techniques, an experimental setup system for simultaneous measurement of dynamic displacement and strain on a flexible cantilever beam using two fiber Bragg gratings (FBGs) in a single fiber is proposed. To realize high-speed multiplexing and demodulation, a configuration incorporating a coarse wavelength-division multiplexing (CWDM) technique and an FBG transmission filter is implemented. The cantilever beam is subjected to steel-ball impact from which the dynamic multipoint displacement/strain sensing performances of the CWDM and FBG filter-based sensing system are demonstrated. Experimental results in temporal and frequency domain are compared with those obtained by the finite element method (FEM) predictions based on identification of the impact-loading history. A noncontact Fotonic displacement sensor and a polyvinylidene-fluoride film (PVDF) strain sensor are also used for comparison. With transient and resonant frequency simulations conducted by the FEM, loading effects of the sensing system are examined. The results obtained in this study indicate that the proposed CWDM and FBG filter-based sensing system is capable of performing simultaneous multipoint displacement/strain measurements in a single fiber with large bandwidth, high sensitivity, and low intensity loss. PMID:27140584

  2. Simultaneous measurement of dynamic displacement and strain in a single fiber using coarse wavelength-division multiplexing and fiber Bragg-grating filter-based sensing system.

    PubMed

    Chuang, Kuo-Chih; Ma, Chien-Ching; Wang, Hwa-Chun

    2016-03-20

    Displacement and strain, two of the most important physical quantities in experimental solid mechanics, are seldomly measured simultaneously in a single experimental configuration. In order to provide and improve corresponding sensing techniques, an experimental setup system for simultaneous measurement of dynamic displacement and strain on a flexible cantilever beam using two fiber Bragg gratings (FBGs) in a single fiber is proposed. To realize high-speed multiplexing and demodulation, a configuration incorporating a coarse wavelength-division multiplexing (CWDM) technique and an FBG transmission filter is implemented. The cantilever beam is subjected to steel-ball impact from which the dynamic multipoint displacement/strain sensing performances of the CWDM and FBG filter-based sensing system are demonstrated. Experimental results in temporal and frequency domain are compared with those obtained by the finite element method (FEM) predictions based on identification of the impact-loading history. A noncontact Fotonic displacement sensor and a polyvinylidene-fluoride film (PVDF) strain sensor are also used for comparison. With transient and resonant frequency simulations conducted by the FEM, loading effects of the sensing system are examined. The results obtained in this study indicate that the proposed CWDM and FBG filter-based sensing system is capable of performing simultaneous multipoint displacement/strain measurements in a single fiber with large bandwidth, high sensitivity, and low intensity loss.

  3. [Extracellular slime production and adhesion of Morganella morganii strains to polystyrene].

    PubMed

    Michalska, Anna; Zalas-Wiecek, Patrycja; Sielska, Barbara; Gospodarek, Eugenia

    2011-01-01

    The aim of this study was the evaluation of the ability of extracellular slime production and adhesive properties of M. morganii strains. This study included 50 of M. morganii strains isolated from clinical samples. All of these strains were isolated in the Clinical Microbiology Department of dr. A. Jurasz University Hospital in 2008-2009. Five (10.0%) out of 50. M. morganii strains demonstrated extracellular slime production. Adherence to polystyrene revealed 36 (72.0%) of M. morganii strains in it 6 strains (12.0%) adhered strongly, medium - 12 (24.0%) and weakly - 18 (36.0%).

  4. Export of Extracellular Polysaccharides Modulates Adherence of the Cyanobacterium Synechocystis

    SciTech Connect

    Fisher, ML; Allen, R; Luo, YQ; Curtiss, R

    2013-09-10

    The field of cyanobacterial biofuel production is advancing rapidly, yet we know little of the basic biology of these organisms outside of their photosynthetic pathways. We aimed to gain a greater understanding of how the cyanobacterium Synechocystis PCC 6803 (Synechocystis, hereafter) modulates its cell surface. Such understanding will allow for the creation of mutants that autoflocculate in a regulated way, thus avoiding energy intensive centrifugation in the creation of biofuels. We constructed mutant strains lacking genes predicted to function in carbohydrate transport or synthesis. Strains with gene deletions of slr0977 (predicted to encode a permease component of an ABC transporter), slr0982 (predicted to encode an ATP binding component of an ABC transporter) and slr1610 (predicted to encode a methyltransferase) demonstrated flocculent phenotypes and increased adherence to glass. Upon bioinformatic inspection, the gene products of slr0977, slr0982, and slr1610 appear to function in O-antigen (OAg) transport and synthesis. However, the analysis provided here demonstrated no differences between OAg purified from wild-type and mutants. However, exopolysaccharides (EPS) purified from mutants were altered in composition when compared to wild-type. Our data suggest that there are multiple means to modulate the cell surface of Synechocystis by disrupting different combinations of ABC transporters and/or glycosyl transferases. Further understanding of these mechanisms may allow for the development of industrially and ecologically useful strains of cyanobacteria. Additionally, these data imply that many cyanobacterial gene products may possess as-yet undiscovered functions, and are meritorious of further study.

  5. The Role of Adherence and Retreatment in De Novo Emergence of MDR-TB

    PubMed Central

    Cadosch, Dominique; Abel zur Wiesch, Pia; Kouyos, Roger; Bonhoeffer, Sebastian

    2016-01-01

    Treatment failure after therapy of pulmonary tuberculosis (TB) infections is an important challenge, especially when it coincides with de novo emergence of multi-drug-resistant TB (MDR-TB). We seek to explore possible causes why MDR-TB has been found to occur much more often in patients with a history of previous treatment. We develop a mathematical model of the replication of Mycobacterium tuberculosis within a patient reflecting the compartments of macrophages, granulomas, and open cavities as well as parameterizing the effects of drugs on the pathogen dynamics in these compartments. We use this model to study the influence of patient adherence to therapy and of common retreatment regimens on treatment outcome. As expected, the simulations show that treatment success increases with increasing adherence. However, treatment occasionally fails even under perfect adherence due to interpatient variability in pharmacological parameters. The risk of generating MDR de novo is highest between 40% and 80% adherence. Importantly, our simulations highlight the double-edged effect of retreatment: On the one hand, the recommended retreatment regimen increases the overall success rate compared to re-treating with the initial regimen. On the other hand, it increases the probability to accumulate more resistant genotypes. We conclude that treatment adherence is a key factor for a positive outcome, and that screening for resistant strains is advisable after treatment failure or relapse. PMID:26967493

  6. Natural Strain

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.

    1997-01-01

    Logarithmic strain is the preferred measure of strain used by materials scientists, who typically refer to it as the "true strain." It was Nadai who gave it the name "natural strain," which seems more appropriate. This strain measure was proposed by Ludwik for the one-dimensional extension of a rod with length l. It was defined via the integral of dl/l to which Ludwik gave the name "effective specific strain." Today, it is after Hencky, who extended Ludwik's measure to three-dimensional analysis by defining logarithmic strains for the three principal directions.

  7. Pseudomonas cepacia adherence to respiratory epithelial cells is enhanced by Pseudomonas aeruginosa

    SciTech Connect

    Saiman, L.; Cacalano, G.; Prince, A. )

    1990-08-01

    Pseudomonas aeruginosa and Pseudomonas cepacia are both opportunistic pathogens of patients with cystic fibrosis. The binding characteristics of these two species were compared to determine if they use similar mechanisms to adhere to respiratory epithelial cells. P. cepacia 249 was shown to be piliated, but there was no detectable homology between P. aeruginosa pilin gene probes and P. cepacia genomic DNA. P. cepacia and P. aeruginosa did not appear to compete for epithelial receptors. In the presence of purified P. aeruginosa pili, the adherence of 35S-labeled strain 249 to respiratory epithelial monolayers was unaffected, while that of P. aeruginosa PAO1 was decreased by 55%. The binding of P. cepacia 249 and 715j was increased by 2.4-fold and 1.5-fold, respectively, in the presence of an equal inoculum of PAO1. Interbacterial agglutination contributed to the increased adherence of P. cepacia, as the binding of 249 was increased twofold in the presence of irradiated PAO1. PAO1 exoproducts had a marked effect in enhancing the ability of the P. cepacia strains to adhere to the epithelial monolayers. A PAO1 supernatant increased the binding of 249 by eightfold and that of 715j by fourfold. Thus, there appears to be a synergistic relationship between P. aeruginosa and P. cepacia in which PAO1 exoproducts modify the epithelial cell surface, exposing receptors and facilitating increased P. cepacia attachment.

  8. Escherichia coli isolated from a Crohn's disease patient adheres, invades, and induces inflammatory responses in polarized intestinal epithelial cells.

    PubMed

    Eaves-Pyles, Tonyia; Allen, Christopher A; Taormina, Joanna; Swidsinski, Alexander; Tutt, Christopher B; Jezek, G Eric; Islas-Islas, Martha; Torres, Alfredo G

    2008-07-01

    Inflammatory diseases of the intestinal tract are a major health concern both in the United States and around the world. Evidence now suggests that a new category of Escherichia coli, designated Adherent Invasive E. coli (AIEC) is highly prevalent in Crohn's Disease (CD) patients. AIEC strains have been shown to colonize and adhere to intestinal epithelial cells (IEC). However, the role AIEC strains play in the induction of an inflammatory response is not known. Therefore, we examined several E. coli strains (designated LF82, O83:H1, 6604 and 6655) that were isolated from CD patients for their ability to induce inflammation in two IEC, Caco-2BBe and T-84 cells. Results showed that each strain had varying abilities to adhere to and invade IEC as well as induced cytokine secretion from polarized IEC. However, E. coli O83:H1 displayed the best characteristics of AIEC strains as compared to the prototype AIEC strain LF82, inducing cytokine secretion from IEC and promoting immune cell migration through IEC. Upon further analysis, E. coli O83:H1 did not harbor virulence genes present in known pathogenic intestinal organisms. Further characterization of E. coli O83:H1 virulence determinants showed that a non-flagellated O83:H1 strain significantly decreased the organism's ability to adhere to and invade both IEC and elicit IEC cytokine secretion compared to the wild type and complemented strains. These findings demonstrate that E. coli O83:H1 possesses the characteristics of the AIEC LF82 strain that may contribute to the low-grade, chronic inflammation observed in Crohn's disease. PMID:17900983

  9. Experimental and numerical analysis of a hybrid FBG long gauge sensor for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Torres Górriz, Benjamín; Calderón García, Pedro; Payá-Zaforteza, Ignacio J.; Sales Maicas, Salvador

    2014-12-01

    This paper presents a new long gauge sensor for structural health monitoring based on the use of fiber Bragg gratings. The proposed sensor has the advantage over existing sensors that it does not require prestressing of the optical fiber. The development consisted of numerical studies complemented by experimental tests to analyze: (1) the strain transfer between the sensor and the host structure; (2) the influence of sensor axial stiffness on the structural behavior of the host structure; (3) the influence of the mechanical properties of the adhesive used to fix the sensor and (4) the failure modes of the sensor (buckling and shear stress of sensor anchors).

  10. Pathogenesis of Afa/Dr Diffusely Adhering Escherichia coli

    PubMed Central

    Servin, Alain L.

    2005-01-01

    Over the last few years, dramatic increases in our knowledge about diffusely adhering Escherichia coli (DAEC) pathogenesis have taken place. The typical class of DAEC includes E. coli strains harboring AfaE-I, AfaE-II, AfaE-III, AfaE-V, Dr, Dr-II, F1845, and NFA-I adhesins (Afa/Dr DAEC); these strains (i) have an identical genetic organization and (ii) allow binding to human decay-accelerating factor (DAF) (Afa/DrDAF subclass) or carcinoembryonic antigen (CEA) (Afa/DrCEA subclass). The atypical class of DAEC includes two subclasses of strains; the atypical subclass 1 includes E. coli strains that express AfaE-VII, AfaE-VIII, AAF-I, AAF-II, and AAF-III adhesins, which (i) have an identical genetic organization and (ii) do not bind to human DAF, and the atypical subclass 2 includes E. coli strains that harbor Afa/Dr adhesins or others adhesins promoting diffuse adhesion, together with pathogenicity islands such as the LEE pathogenicity island (DA-EPEC). In this review, the focus is on Afa/Dr DAEC strains that have been found to be associated with urinary tract infections and with enteric infection. The review aims to provide a broad overview and update of the virulence aspects of these intriguing pathogens. Epidemiological studies, diagnostic techniques, characteristic molecular features of Afa/Dr operons, and the respective role of Afa/Dr adhesins and invasins in pathogenesis are described. Following the recognition of membrane-bound receptors, including type IV collagen, DAF, CEACAM1, CEA, and CEACAM6, by Afa/Dr adhesins, activation of signal transduction pathways leads to structural and functional injuries at brush border and junctional domains and to proinflammatory responses in polarized intestinal cells. In addition, uropathogenic Afa/Dr DAEC strains, following recognition of β1 integrin as a receptor, enter epithelial cells by a zipper-like, raft- and microtubule-dependent mechanism. Finally, the presence of other, unknown virulence factors and the way that

  11. [Challenges of adolescents' adherence to therapy].

    PubMed

    Brand, P L P; Kaptein, A A; Janssens, L P F; Klok, T

    2016-01-01

    Non-adherence occurs at any age, in all chronic diseases, and has a major impact on clinical outcomes. Non-adherence is primarily determined by perceptions of illness and medication beliefs. During puberty, adolescents attain independence from their parents and attach to their peers. This complicates successful self-management of chronic illness, because the adolescents avoid standing out from their peers. Discussion of barriers hindering successful self-management in adolescents can be promoted by seeing the patient alone, without the parents being present, and by acknowledging the patient's independence and responsibilities. PMID:27581866

  12. [Supporting adherence to drug therapy in psychiatry].

    PubMed

    Oksanen, Jorma

    2015-01-01

    Maintenance therapy to reduce the risk of recurrence is an essential part of treatment of schizophrenia, bipolar disorder and major depressive disorder, but poor treatment adherence is common, impairing the treatment outcome. Improvement in the adherence to drug therapy requires a good therapeutic relationship. The patient and her/his family must be provided with information about the illness and its treatment. Drug therapy must be optimized on an individual basis. The use of long-acting antipsychotic injections should be encouraged. Regular contact with patients under long-term treatment must be maintained. The use of experts by experience is an effective supportive measure. PMID:26485936

  13. MEMS Graphene Strain Sensor

    NASA Astrophysics Data System (ADS)

    Young, Clinton Wen-Chieh

    Graphene is a two dimensional honeycomb structure of sp2 hybridized carbon atoms that has possibilities in many applications due to its excellent mechanical and electrical properties. One application for Graphene is in the field of sensors. Graphene's electronic properties do not degrade when it undergoes mechanical strain which is advantageous for strain sensors. In this thesis, certain properties, such as the piezo-resistivity and flexibility, of graphene will be explored to show how they can be utilized to make a strain sensing device. Our original fabrication process of patterning graphene and the transfer process of graphene onto a flexible substrate will be discussed. The development of a stretchable and flexible graphene based rosette strain sensor will also be detailed. Developing a novel, reliable patterning process for the graphene is the first step to manufacture a stretchable graphene based sensor. The graphene was patterned using a photolithography and etching process that was developed by our research team, then it was transferred to a flexible polymer substrate with the use of a combination of soft lithography and wet etching of the Ni foil with ferric chloride solution. Graphene patterning is an essential step in fabricating reliable and sensitive sensors. With this process, graphene can be consistently patterned into different shapes and sizes. To utilize the graphene as the sensing material it also needs to be transferred onto a flexible substrate. The innovative transfer process developed by our research team consistently adheres graphene to a flexible PDMS substrate while removing the original nickel substrate. In the end, the graphene was transferred from the metal substrate to the desired flexible substrate. This process was repeated multiple times to create a stack and multilayer device. While many graphene-based strain sensors have been developed, they are uni-directional and can only measure the strain applied on the sensor in a principle

  14. Natural Strain

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.

    1995-01-01

    The purpose of this paper is to present a consistent and thorough development of the strain and strain-rate measures affiliated with Hencky. Natural measures for strain and strain-rate, as I refer to them, are first expressed in terms of of the fundamental body-metric tensors of Lodge. These strain and strain-rate measures are mixed tensor fields. They are mapped from the body to space in both the Eulerian and Lagrangian configurations, and then transformed from general to Cartesian fields. There they are compared with the various strain and strain-rate measures found in the literature. A simple Cartesian description for Hencky strain-rate in the Lagrangian state is obtained.

  15. Design of distributed FBG vibration measuring system based on Fabry-Perot tunable filter

    NASA Astrophysics Data System (ADS)

    Zhang, Cheng; Miao, Changyun; Li, Hongqiang; Gao, Hua; Gan, Jingmeng

    2011-11-01

    A distributed optical fiber grating wavelength interrogator based on fiber Fabry Perot tunable filter(FFP-TF) was proposed, which could measure dynamic strain or vibration of multi-sensing fiber gratings in one optical fiber by time division way. The wavelength demodulated mathematical model was built, the formulas of system output voltage and sensitivity were deduced and the method of finding static operating point was determined. The wavelength drifting characteristic of FFP-TF was discussed when the center wavelength of FFP-TF was set on the static operating point. A wavelength locking method was proposed by introducing a high-frequency driving voltage signal. A demodulated system was established based on Labview and its demodulated wavelength dynamic range is 290pm in theory. In experiment, by digital filtering applied to the system output data, 100Hz and 250Hz vibration signals were measured. The experiment results proved the feasibility of the demodulated method.

  16. FBG application in bridge health monitoring system of Wuhan Yangtze River 2nd Bridge

    NASA Astrophysics Data System (ADS)

    Liu, Jun

    2009-10-01

    For the traditional resistance strain sensor's shortage,for example,their stability,durability and monitoring scorpe could not satisfied the requirement of bridge monitoring system,put forward to adopt advanced fiber-optic bragg grating sensor and its technology to build up the bridge health monitoring system.Analysed the application scope and aim of difference kinds of fiber bragg grating sensors used, including stress strain sensors,temperature sensors,crack sensors and testing force ring sensors.According to the key construction sections as the project designed,expatiated their specific installation methods and construction craftwork in Wuhan Yangtze River 2th bridge.It formed distributed fiber sensing network of bridge with large-scale located fiber-optic bragg grating sensors, and pointed out the becareful prodeeding when to link no more than twenty sensors to one fiber for the demodulator precision.Discussed how to construct the data acquisition system and its function via the sensors and their demodulator.One fiber of the linked sensors connected to one channel of the demodulator and all together reached sixteen channels.The demodulator were connected to the switch through rj45 interface and communicated with the acquisition server.Designed the software program of data acquisition software system and the database,which used the Sqlite of the embed database to storage the configure information and receive the data through the TCP/IP protocol.It has been build a bridge health monitoring system base on fiber bragg grating technology.

  17. Fiber-Optic Strain and Temperature Monitoring System for DUSEL

    NASA Astrophysics Data System (ADS)

    Wang, H. F.; Maclaughlin, M.; Fratta, D.; Murdoch, L. C.

    2009-12-01

    The opportunity to understand the response of rock masses to stresses deep within the earth's crust as a function of spatial and temporal scale is at the center of the geomechanics research program proposed for DUSEL. Within the 10-km3 volume of the former Homestake mine, deformations are expected from earth tides, effective stress changes caused by mine dewatering, seasonal water table changes, and new excavations as well as from long-term creep of drifts and shafts. Data from a whole-mine deformation monitoring and measurement system are integral to calibrating a mine-scale, mechanical and hydrological finite-element model of laboratory and detector space. A synergistic objective of a long-term, state-of-the-art monitoring system is to ensure shaft, tunnel, and cavern stability as well as occupant safety. Fiber-optic sensors are highly stable over long periods of time and they can be daisy-chained to significantly simplify the logistics of acquiring data from dozens of sensors. Temperature measurements over large spatial scales in fluid-saturated boreholes can delineate fluid-flow paths and can be deployed as a secondary monitoring system for ventilation and anomalous air temperatures. Two types of fiber-optic sensors are available: distributed strain and temperature (DST) and Fiber Bragg Grating (FBG). DST sensors can be installed over kilometers of distance with measurement resolutions of 1-to-10 microstrains and 0.1°C over intervals of 1-to-2 meters. FBG strain gages and displacement transducers function the same as their electrical counterparts, save for the underlying physics in that displacements are measured as a shift in the spacing of a Bragg grating embedded into the optical fiber. These systems are highly scalable as more than 50,000 points of temperature and strain measurements can be collected from a single fiber-optic cable. Other fiber-based sensors, e.g., acceleration, air pressure, and gases, are also available and can become part of a fiber

  18. Moraxella catarrhalis Expresses a Cardiolipin Synthase That Impacts Adherence to Human Epithelial Cells

    PubMed Central

    Buskirk, Sean W.

    2014-01-01

    The major phospholipid constituents of Moraxella catarrhalis membranes are phosphatidylglycerol, phosphatidylethanolamine, and cardiolipin (CL). However, very little is known regarding the synthesis and function of these phospholipids in M. catarrhalis. In this study, we discovered that M. catarrhalis expresses a cardiolipin synthase (CLS), termed MclS, that is responsible for the synthesis of CL within the bacterium. The nucleotide sequence of mclS is highly conserved among M. catarrhalis isolates and is predicted to encode a protein with significant amino acid similarity to the recently characterized YmdC/ClsC protein of Escherichia coli. Isogenic mclS mutant strains were generated in M. catarrhalis isolates O35E, O12E, and McGHS1 and contained no observable levels of CL. Site-directed mutagenesis of a highly conserved HKD motif of MclS also resulted in a CL-deficient strain. Moraxella catarrhalis, which depends on adherence to epithelial cells for colonization of the human host, displays significantly reduced levels of adherence to HEp-2 and A549 cell lines in the mclS mutant strains compared to wild-type bacteria. The reduction in adherence appears to be attributed to the absence of CL. These findings mark the first instance in which a CLS has been related to a virulence-associated trait. PMID:24142255

  19. Lactobacillus reuteri Inhibition of Enteropathogenic Escherichia coli Adherence to Human Intestinal Epithelium.

    PubMed

    Walsham, Alistair D S; MacKenzie, Donald A; Cook, Vivienne; Wemyss-Holden, Simon; Hews, Claire L; Juge, Nathalie; Schüller, Stephanie

    2016-01-01

    Enteropathogenic Escherichia coli (EPEC) is a major cause of diarrheal infant death in developing countries, and probiotic bacteria have been shown to provide health benefits in gastrointestinal infections. In this study, we have investigated the influence of the gut symbiont Lactobacillus reuteri on EPEC adherence to the human intestinal epithelium. Different host cell model systems including non-mucus-producing HT-29 and mucus-producing LS174T intestinal epithelial cell lines as well as human small intestinal biopsies were used. Adherence of L. reuteri to HT-29 cells was strain-specific, and the mucus-binding proteins CmbA and MUB increased binding to both HT-29 and LS174T cells. L. reuteri ATCC PTA 6475 and ATCC 53608 significantly inhibited EPEC binding to HT-29 but not LS174T cells. While pre-incubation of LS174T cells with ATCC PTA 6475 did not affect EPEC attaching/effacing (A/E) lesion formation, it increased the size of EPEC microcolonies. ATCC PTA 6475 and ATCC 53608 binding to the mucus layer resulted in decreased EPEC adherence to small intestinal biopsy epithelium. Our findings show that L. reuteri reduction of EPEC adhesion is strain-specific and has the potential to target either the epithelium or the mucus layer, providing further rationale for the selection of probiotic strains. PMID:26973622

  20. DLC coatings for UHMWPE: relationship between bacterial adherence and surface properties.

    PubMed

    Del Prado, G; Terriza, A; Ortiz-Pérez, A; Molina-Manso, D; Mahillo, I; Yubero, F; Puértolas, J A; Manrubia-Cobo, M; Gómez Barrena, E; Esteban, J

    2012-10-01

    Development of intrinsically antibacterial surfaces is of key importance in the context of prostheses used in orthopedic surgery. This work presents a thorough study of several plasma-based coatings that may be used with this functionality: diamond-like carbon (DLC), fluorine-doped DLC (F-DLC), and a high-fluorine-content-carbon-fluor polymer (CF(X)). The coatings were obtained by a radio-frequency plasma-assisted deposition on ultra high molecular weight polyethylene (UHMWPE) samples and physicochemical properties of the coated surfaces were correlated with their antibacterial performance against collection and clinical Staphylococcus aureus and Staphylococcus epidermidis strains. The fluorine content and the relative amount of C-C and C-F bonds were controlled by X-ray photoelectron spectroscopy, and hydrophobicity and surface tension by contact angle measurements. Surface roughness was studied by Atomic Force Microscopy. Additional nanoidentation studies were performed for DLC and F-DLC coatings. Unpaired t test and regression linear models evaluated the adherence of S. aureus and S. epidermidis on raw and coated UHMWPE samples. Comparing with UHMWPE, DLC/UHMWPE was the least adherent surface with independence of the bacterial species, finding significant reductions (p ≤ 0.001) for nine staphylococci strains. Bacterial adherence was also significantly reduced in F-DLC/ UHMWPE and CFx/UHMWPE for six strains.

  1. Survival of Adhering Staphylococci during Exposure to a Quaternary Ammonium Compound Evaluated by Using Atomic Force Microscopy Imaging▿

    PubMed Central

    Crismaru, Mihaela; Asri, Lia A. T. W.; Loontjens, Ton J. A.; Krom, Bastiaan P.; de Vries, Joop; van der Mei, Henny C.; Busscher, Henk J.

    2011-01-01

    Effects of a quaternary ammonium compound (QAC) on the survival of adhering staphylococci on a surface were investigated using atomic force microscopy (AFM). Four strains with different minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) for the QAC were exposed to three different concentrations of the QAC in potassium phosphate buffer (0.5×, 1×, and 2× MBC) while adhering to glass. Adhering staphylococci were repeatedly imaged with AFM in the contact mode, and the cell surface was found to wrinkle upon progressive exposure to the QAC until bacteria disappeared from the substratum. Higher concentrations of QAC yielded faster wrinkling and the disappearance of bacteria during imaging. Two slime-producing staphylococcal strains survived longer on the surface than two non-slime-producing strains despite similar MICs and MBCs. All staphylococci adhering in unscanned areas remained adhering during exposure to QAC. Since MICs and MBCs did not relate to bacterial cell surface hydrophobicities and zeta potentials, survival on the surface is probably not determined by the direct interaction of QAC molecules with the cell surface. Instead, it is suggested that the pressure of the AFM tip assists the incorporation of QAC molecules in the membrane and enhances their bactericidal efficacy. In addition, the prolonged survival under pressure from slime-producing strains on a surface may point to a new protective role of slime as a stress absorber, impeding the incorporation of QAC molecules. The addition of Ca2+ ions to a QAC solution yielded longer survival of intact, adhering staphylococci, suggesting that Ca2+ ions can impede the exchange of membrane Ca2+ ions required for QAC incorporation. PMID:21876063

  2. E-health strategies to support adherence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adherence to healthy behaviors and self-care strategies is a concern among clinicians. E-health applications, such as the internet, personal communication devices, electronic health records and web portals, and electronic games, may be a way to provide health information in a way that is reliable, c...

  3. Adherence to Sports-Injury Rehabilitation Programs.

    ERIC Educational Resources Information Center

    Fisher, A. Craig; And Others

    1988-01-01

    Analysis of 41 injured college athletes' responses to a questionnaire revealed that those athletes who adhered to their rehabilitation program were more self-motivated, tolerated pain better, perceived that they worked harder at their rehabilitation, and were less bothered by scheduling of sessions and athletic training environmental conditions.…

  4. Adherence to Exercise and Physical Activity: Preface.

    ERIC Educational Resources Information Center

    Morgan, William P.; Dishman, Rod K.

    2001-01-01

    Introduces a collection of papers on adherence to exercise programs and physical activity from the 2000 American Academy of Kinesiology and Physical Education conference, which included research on middle school boys and girls, college men and women, and men and women in the later years, as well as on the more traditional subject of middle aged…

  5. The role of Listeria monocytogenes cell wall surface anchor protein LapB in virulence, adherence, and intracellular replication

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lmof2365_2117 is a Listeria monocytogenes putative cell wall surface anchor protein with a conserved domain found in collagen binding proteins. We constructed a deletion mutation in lmof2365_2117 in serotype 4b strain F2365, evaluated its virulence, and determined its ability to adhere and invade co...

  6. Simultaneous measurement of strain and temperature by two peanut tapers with embedded fiber Bragg grating.

    PubMed

    Lv, Lingya; Wang, Sumei; Jiang, Lan; Zhang, Fei; Cao, Zhitao; Wang, Peng; Jiang, Yi; Lu, Yongfeng

    2015-12-20

    A compact optical fiber sensor for simultaneous measurement of strain and temperature is designed and experimentally investigated. The proposed sensor consists of a two-peanut-taper Mach-Zehnder interferometer (MZI) and in-line embedded fiber Bragg grating (FBG). The sensor at a length of 35 mm presents strain sensitivities 1.07  pm/με and 0.891  pm/με, the temperature sensitivities are 55.35  pm/°C and 10.85  pm/°C, for MZI and FBG, respectively. Through tapering the center of the sensor by a fusion splicer, the strain sensitivity of the MZI is improved to 1.93  pm/με. The resolutions for strain and temperature measurement are ±3.104  με and ±0.194°C with the wavelength resolution of 5 pm. The experimental results show that the sensor is able to simultaneously measure strain and temperature by sensitivity matrix with advantages such as simple structure, compact size, ease of fabrication, low cost, etc. PMID:26837035

  7. Factors affecting medication adherence in elderly people

    PubMed Central

    Jin, Hyekyung; Kim, Yeonhee; Rhie, Sandy Jeong

    2016-01-01

    Background Little is known about the functional health literacy (FHL) associated with medication adherence in elderly patients. The aim of this study was to examine the FHL among older adults and identify influencing factors that can predict medication adherence. Methods This was a cross-sectional survey. Participants (n=160) aged 65 years and older were selected from outpatient clinics of 3 tertiary care hospitals, 6 community pharmacies, and 2 senior centers between November 1 and 30, 2014. The participants’ FHL was measured using the Korean Functional Health Literacy Test, which consists of 15 items including 8 numeracy and 7 reading comprehension items. Medication adherence was measured by the Adherence to Refills and Medication Scale. Descriptive statistics, chi-square or Fisher’s exact test, and multiple regression analyses were used to analyze the data. Results The mean score of the total FHL was 7.72±3.51 (range 0–15). The percentage of the total number of correct answers for the reading comprehension subtest and numeracy subtest were 48.1% and 54.4%, respectively. Among 160 participants, 52.5% showed low adherence to medication. The factors affecting medication adherence included the patient’s degree of satisfaction with the service (β=−0.215, P=0.022), sufficient explanation of medication counseling (β=−0.335, P=0.000), education level (β=−0.153, P=0.045), health-related problems (β=−0.239, P=0.004), and dosing frequency (β=0.189, P=0.018). Conclusion In this study, we found medication adherence of elderly patients was associated with education level, health-related problems, dosing frequency, satisfaction with patient counseling, and explanation of medication, but no association was found with FHL. Pharmacists should consider elderly patients’ individual characteristics such as educational background and specific patient-related health problems, provide sufficient information and explanation of medication, and ensure patient

  8. Production of a mouse strain with impaired glucose tolerance by systemic heterozygous knockout of the glucokinase gene and its feasibility as a prediabetes model.

    PubMed

    Saito, Mikako; Kaneda, Asako; Sugiyama, Tae; Iida, Ryousuke; Otokuni, Keiko; Kaburagi, Misako; Matsuoka, Hideaki

    2015-01-01

    Exon II of glucokinase (Gk) was deleted to produce a systemic heterozygous Gk knockout (Gk(+/-)) mouse. The relative expression levels of Gk in the heart, lung, liver, stomach, and pancreas in Gk(+/-) mice ranged from 0.41-0.68 versus that in wild (Gk(+/+)) mice. On the other hand, its expression levels in the brain, adipose tissue, and muscle ranged from 0.95-1.03, and its expression levels in the spleen and kidney were nearly zero. Gk knockout caused no remarkable off-target effect on the expression of 7 diabetes causing genes (Shp, Hnf1a, Hnf1b, Irs1, Irs2, Kir6.2, and Pdx1) in 10 organs. The glucose tolerance test was conducted to determine the blood glucose concentrations just after fasting for 24 h (FBG) and at 2 h after high-glucose application (GTT2h). The FBG-GTT2h plots obtained with the wild strain fed the control diet (CD), Gk(+/-) strain fed the CD, and Gk(+/-) strain fed the HFD were distributed in separate areas in the FBG-GTT2h diagram. The respective areas could be defined as the normal state, prediabetes state, and diabetes state, respectively. Based on the results, the criteria for prediabetes could be defined for the Gk(+/-) strain developed in this study. PMID:25765873

  9. Production of a mouse strain with impaired glucose tolerance by systemic heterozygous knockout of the glucokinase gene and its feasibility as a prediabetes model

    PubMed Central

    SAITO, Mikako; KANEDA, Asako; SUGIYAMA, Tae; IIDA, Ryousuke; OTOKUNI, Keiko; KABURAGI, Misako; MATSUOKA, Hideaki

    2015-01-01

    Exon II of glucokinase (Gk) was deleted to produce a systemic heterozygous Gk knockout (Gk+/−) mouse. The relative expression levels of Gk in the heart, lung, liver, stomach, and pancreas in Gk+/− mice ranged from 0.41–0.68 versus that in wild (Gk+/+) mice. On the other hand, its expression levels in the brain, adipose tissue, and muscle ranged from 0.95–1.03, and its expression levels in the spleen and kidney were nearly zero. Gk knockout caused no remarkable off-target effect on the expression of 7 diabetes causing genes (Shp, Hnf1a, Hnf1b, Irs1, Irs2, Kir6.2, and Pdx1) in 10 organs. The glucose tolerance test was conducted to determine the blood glucose concentrations just after fasting for 24 h (FBG) and at 2 h after high-glucose application (GTT2h). The FBG-GTT2h plots obtained with the wild strain fed the control diet (CD), Gk+/− strain fed the CD, and Gk+/− strain fed the HFD were distributed in separate areas in the FBG-GTT2h diagram. The respective areas could be defined as the normal state, prediabetes state, and diabetes state, respectively. Based on the results, the criteria for prediabetes could be defined for the Gk+/− strain developed in this study. PMID:25765873

  10. FBG inscription in non-hydrogenated SMF28 fiber with a ns Q-switched Nd:VO4 laser at 213 nm

    NASA Astrophysics Data System (ADS)

    Berrang, Bianca; Polz, Leonhard; Kuttler, Rolf; Bartschke, Jürgen; Roths, Johannes

    2013-05-01

    Fiber Bragg grating (FBG) inscription efficiencies with a nanosecond (ns) KrF-Excimer laser source at 248 nm and with a ns Q-switched, 5th-harmonic Nd:VO4 laser source at 213 nm were compared. With both laser sources the phase mask method was used for FBG inscription. The growth process of the refractive index change during UV-exposure is presented as a function of cumulated fluence for inscription in standard non-hydrogenated SMF28 fibers. The inscription efficiency was found to be significantly higher for the 213 nm than for the 248 nm radiation, indicating a higher photosensitivity at 213 nm compared to 248 nm in low Ge-doped fibers.

  11. Lactobacilli Interfere with Streptococcus pyogenes Hemolytic Activity and Adherence to Host Epithelial Cells.

    PubMed

    Saroj, Sunil D; Maudsdotter, Lisa; Tavares, Raquel; Jonsson, Ann-Beth

    2016-01-01

    Streptococcus pyogenes [Group A streptococcus (GAS)], a frequent colonizer of the respiratory tract mucosal surface, causes a variety of human diseases, ranging from pharyngitis to the life-threatening streptococcal toxic shock-like syndrome. Lactobacilli have been demonstrated to colonize the respiratory tract. In this study, we investigated the interference of lactobacilli with the virulence phenotypes of GAS. The Lactobacillus strains L. rhamnosus Kx151A1 and L. reuteri PTA-5289, but not L. salivarius LMG9477, inhibited the hemolytic activity of S. pyogenes S165. The inhibition of hemolytic activity was attributed to a decrease in the production of streptolysin S (SLS). Conditioned medium (CM) from the growth of L. rhamnosus Kx151A1 and L. reuteri PTA-5289 was sufficient to down-regulate the expression of the sag operon, encoding SLS. The Lactobacillus strains L. rhamnosus Kx151A1, L. reuteri PTA-5289, and L. salivarius LMG9477 inhibited the initial adherence of GAS to host epithelial cells. Intriguingly, competition with a combination of Lactobacillus species reduced GAS adherence to host cells most efficiently. The data suggest that an effector molecule released from certain Lactobacillus strains attenuates the production of SLS at the transcriptional level and that combinations of Lactobacillus strains may protect the pharyngeal mucosa more efficiently from the initial colonization of GAS. The effector molecules released from Lactobacillus strains affecting the virulence phenotypes of pathogens hold potential in the development of a new generation of therapeutics. PMID:27524981

  12. Lactobacilli Interfere with Streptococcus pyogenes Hemolytic Activity and Adherence to Host Epithelial Cells.

    PubMed

    Saroj, Sunil D; Maudsdotter, Lisa; Tavares, Raquel; Jonsson, Ann-Beth

    2016-01-01

    Streptococcus pyogenes [Group A streptococcus (GAS)], a frequent colonizer of the respiratory tract mucosal surface, causes a variety of human diseases, ranging from pharyngitis to the life-threatening streptococcal toxic shock-like syndrome. Lactobacilli have been demonstrated to colonize the respiratory tract. In this study, we investigated the interference of lactobacilli with the virulence phenotypes of GAS. The Lactobacillus strains L. rhamnosus Kx151A1 and L. reuteri PTA-5289, but not L. salivarius LMG9477, inhibited the hemolytic activity of S. pyogenes S165. The inhibition of hemolytic activity was attributed to a decrease in the production of streptolysin S (SLS). Conditioned medium (CM) from the growth of L. rhamnosus Kx151A1 and L. reuteri PTA-5289 was sufficient to down-regulate the expression of the sag operon, encoding SLS. The Lactobacillus strains L. rhamnosus Kx151A1, L. reuteri PTA-5289, and L. salivarius LMG9477 inhibited the initial adherence of GAS to host epithelial cells. Intriguingly, competition with a combination of Lactobacillus species reduced GAS adherence to host cells most efficiently. The data suggest that an effector molecule released from certain Lactobacillus strains attenuates the production of SLS at the transcriptional level and that combinations of Lactobacillus strains may protect the pharyngeal mucosa more efficiently from the initial colonization of GAS. The effector molecules released from Lactobacillus strains affecting the virulence phenotypes of pathogens hold potential in the development of a new generation of therapeutics.

  13. Lactobacilli Interfere with Streptococcus pyogenes Hemolytic Activity and Adherence to Host Epithelial Cells

    PubMed Central

    Saroj, Sunil D.; Maudsdotter, Lisa; Tavares, Raquel; Jonsson, Ann-Beth

    2016-01-01

    Streptococcus pyogenes [Group A streptococcus (GAS)], a frequent colonizer of the respiratory tract mucosal surface, causes a variety of human diseases, ranging from pharyngitis to the life-threatening streptococcal toxic shock-like syndrome. Lactobacilli have been demonstrated to colonize the respiratory tract. In this study, we investigated the interference of lactobacilli with the virulence phenotypes of GAS. The Lactobacillus strains L. rhamnosus Kx151A1 and L. reuteri PTA-5289, but not L. salivarius LMG9477, inhibited the hemolytic activity of S. pyogenes S165. The inhibition of hemolytic activity was attributed to a decrease in the production of streptolysin S (SLS). Conditioned medium (CM) from the growth of L. rhamnosus Kx151A1 and L. reuteri PTA-5289 was sufficient to down-regulate the expression of the sag operon, encoding SLS. The Lactobacillus strains L. rhamnosus Kx151A1, L. reuteri PTA-5289, and L. salivarius LMG9477 inhibited the initial adherence of GAS to host epithelial cells. Intriguingly, competition with a combination of Lactobacillus species reduced GAS adherence to host cells most efficiently. The data suggest that an effector molecule released from certain Lactobacillus strains attenuates the production of SLS at the transcriptional level and that combinations of Lactobacillus strains may protect the pharyngeal mucosa more efficiently from the initial colonization of GAS. The effector molecules released from Lactobacillus strains affecting the virulence phenotypes of pathogens hold potential in the development of a new generation of therapeutics. PMID:27524981

  14. Corrosion Resistant FBG-Based Quasi-Distributed Sensor for Crude Oil Tank Dynamic Temperature Profile Monitoring

    PubMed Central

    da Silva Marques, Rogério; Prado, Adilson Ribeiro; da Costa Antunes, Paulo Fernando; de Brito André, Paulo Sérgio; Ribeiro, Moisés R. N.; Frizera-Neto, Anselmo; Pontes, Maria José

    2015-01-01

    This article presents a corrosion resistant, maneuverable, and intrinsically safe fiber Bragg grating (FBG)-based temperature optical sensor. Temperature monitoring is a critical activity for the oil and gas industry. It typically involves acquiring the desired parameters in a hazardous and corrosive environment. The use of polytetrafluoroethylene (PTFE) was proposed as a means of simultaneously isolating the optical fiber from the corrosive environment and avoiding undesirable mechanical tensions on the FBGs. The presented sensor head is based on multiple FBGs inscribed in a lengthy single mode fiber. The sensor presents an average thermal sensitivity of 8.82 ± 0.09 pm/°C, resulting in a typical temperature resolution of ~0.1 °C and an average time constant value of 6.25 ± 0.08 s. Corrosion and degradation resistance were verified by infrared spectroscopy and scanning electron microscopy during 90 days exposure to high salinity crude oil samples. The developed sensor was tested in a field pilot test, mimicking the operation of an inland crude tank, demonstrating its abilities to dynamically monitor temperature profile. PMID:26690166

  15. Corrosion Resistant FBG-Based Quasi-Distributed Sensor for Crude Oil Tank Dynamic Temperature Profile Monitoring.

    PubMed

    Marques, Rogério da Silva; Prado, Adilson Ribeiro; Antunes, Paulo Fernando da Costa; André, Paulo Sérgio de Brito; Ribeiro, Moisés R N; Frizera-Neto, Anselmo; Pontes, Maria José

    2015-01-01

    This article presents a corrosion resistant, maneuverable, and intrinsically safe fiber Bragg grating (FBG)-based temperature optical sensor. Temperature monitoring is a critical activity for the oil and gas industry. It typically involves acquiring the desired parameters in a hazardous and corrosive environment. The use of polytetrafluoroethylene (PTFE) was proposed as a means of simultaneously isolating the optical fiber from the corrosive environment and avoiding undesirable mechanical tensions on the FBGs. The presented sensor head is based on multiple FBGs inscribed in a lengthy single mode fiber. The sensor presents an average thermal sensitivity of 8.82 ± 0.09 pm/°C, resulting in a typical temperature resolution of ~0.1 °C and an average time constant value of 6.25 ± 0.08 s. Corrosion and degradation resistance were verified by infrared spectroscopy and scanning electron microscopy during 90 days exposure to high salinity crude oil samples. The developed sensor was tested in a field pilot test, mimicking the operation of an inland crude tank, demonstrating its abilities to dynamically monitor temperature profile. PMID:26690166

  16. Relationship of cell surface morphology and composition of Streptococcus salivarius K+ to adherence and hydrophobicity.

    PubMed Central

    Weerkamp, A H; van der Mei, H C; Slot, J W

    1987-01-01

    The cell surfaces of a range of variants of Streptococcus salivarius HB, altered in cell wall antigen composition, were compared with those of the parent with respect to adherence, ability to adsorb to hexadecane, morphology, and exposure of lipoteichoic acid (LTA). Adherence to host surfaces was measured by using both saliva-coated hydroxyapatite beads and tissue-cultured HeLa cells, and interbacterial adherence was measured by using Veillonella alcalescens V1 cells. Progressive loss of the protease-sensitive fibril classes was generally associated with decreasing ability to adsorb to hexadecane. However, increased exposure of protein antigen C (AgC) increased the apparent hydrophobicity of the cell. This correlated with the finding that AgC was the most hydrophobic of the solubilized fibrillar cell wall antigens. Collectively, this demonstrates that adsorption to hydrophobic ligands is directly related to the density of the fibrillar layer on the cells and the properties and surface exposure of specific fibril classes. The involvement of hydrophobic interactions in AgC-associated attachment was suggested by its sensitivity to low levels of the hydrophobic bond-breaking agent tetramethyl urea, although the reduction was not to the level of adherence observed with strains lacking AgC. However, hydrophobicity was less essential to other adherence reactions. Circumstantial evidence, including immunoelectron microscopy, showing that LTA was virtually absent from the fibrillar layer, whole-cell enzyme-linked immunosorbent assay, suggesting that surface exposure of LTA related inversely to the density of the fibrillar layer, and agarose gel electrophoresis, showing that LTA was not specifically associated with protein fibrillar antigens, strongly suggested that LTA does not confer hydrophobic properties to these cells and is not involved in adherence reactions associated with the cell wall protein antigens. Images PMID:3804445

  17. Using communication skills to improve adherence in children with chronic disease: the adherence equation.

    PubMed

    Brand, Paul L P; Klok, Ted; Kaptein, Adrian A

    2013-12-01

    Nonadherence to maintenance medication is common in paediatric chronic conditions. Despite the common belief that nonadherence is therapy-resistant, and the apparent lack of evidence for successful interventions to improve adherence, there is, in fact, a considerable body of evidence suggesting that adherence can be improved by applying specific communicative consultation skills. These can be summarized as the adherence equation: adherence=follow-up+dialogue+barriers and beliefs+empathy and education => concordance. Close follow-up of children with a chronic condition is needed to establish a therapeutic partnership with the family. Teaching self management skills is not a unidirectional process of providing information, but requires a constructive and collaborative dialogue between the medical team and the family. Identifying barriers to adherence can be achieved in a non-confrontational manner, by showing a genuine interest what the patient's views and preferences are. In particular, parental illness perceptions and medication beliefs should be identified, because they are strong drivers of nonadherence. Through empathic evidence-based education, such perceptions and beliefs can be modified. By applying these strategies, concordance between the child's family and the medical team can be achieved, resulting in optimal adherence to the jointly created treatment plan.

  18. Medication Adherence in Patients with Bipolar Disorder: A Comprehensive Review.

    PubMed

    Levin, Jennifer B; Krivenko, Anna; Howland, Molly; Schlachet, Rebecca; Sajatovic, Martha

    2016-09-01

    Poor medication adherence is a pervasive problem that causes disability and suffering as well as extensive financial costs among individuals with bipolar disorder (BD). Barriers to adherence are numerous and cross multiple levels, including factors related to bipolar pathology and those unique to an individual's circumstances. External factors, including treatment setting, healthcare system, and broader health policies, can also affect medication adherence in people with BD. Fortunately, advances in research have suggested avenues for improving adherence. A comprehensive review of adherence-enhancement interventions for the years 2005-2015 is included. Specific bipolar adherence-enhancement approaches that target knowledge gaps, cognitive patterns, specific barriers, and motivation may be helpful, as may approaches that capitalize on technology or novel drug-delivery systems. However, much work remains to optimally facilitate long-term medication adherence in people with BD. For adherence-enhancement approaches to be widely adapted, they need to be easily accessible, affordable, and practical. PMID:27435356

  19. Porcine intestinal epithelial cell lines as a new in vitro model for studying adherence and pathogenesis of enterotoxigenic Escherichia coli.

    PubMed

    Koh, Seung Y; George, Sajan; Brözel, Volker; Moxley, Rodney; Francis, David; Kaushik, Radhey S

    2008-07-27

    Enterotoxigenic Escherichia coli (ETEC) infections result in large economic losses in the swine industry worldwide. The organism causes diarrhea by adhering to and colonizing enterocytes in the small intestines. While much progress has been made in understanding the pathogenesis of ETEC, no homologous intestinal epithelial cultures suitable for studying porcine ETEC pathogenesis have been described prior to this report. In the current study, we investigated the adherence of various porcine ETEC strains to two porcine (IPEC-1 and IPEC-J2) and one human (INT-407) small intestinal epithelial cell lines. Each cell line was assessed for its ability to support the adherence of E. coli expressing fimbrial adhesins K88ab, K88ac, K88ad, K99, F41, 987P, and F18. Wild-type ETEC expressing K88ab, K88ac, and K88ad efficiently bound to both IPEC-1 and IPEC-J2 cells. An ETEC strain expressing both K99 and F41 bound heavily to both porcine cell lines but an E. coli strain expressing only K99 bound very poorly to these cells. E. coli expressing F18 adhesin strongly bound to IPEC-1 cells but did not adhere to IPEC-J2 cells. The E. coli strains G58-1 and 711 which express no fimbrial adhesins and those that express 987P fimbriae failed to bind to either porcine cell line. Only strains B41 and K12:K99 bound in abundance to INT-407 cells. The binding of porcine ETEC to IPEC-J2, IPEC-1 and INT-407 with varying affinities, together with lack of binding of 987P ETEC and non-fimbriated E. coli strains, suggests strain-specific E. coli binding to these cell lines. These findings suggest the potential usefulness of porcine intestinal cell lines for studying ETEC pathogenesis.

  20. Multi-functional analysis of Klebsiella pneumoniae fimbrial types in adherence and biofilm formation

    PubMed Central

    Alcántar-Curiel, María D.; Blackburn, Dana; Saldaña, Zeus; Gayosso-Vázquez, Catalina; Iovine, Nicole; De la Cruz, Miguel A.; Girón, Jorge A.

    2013-01-01

    Klebsiella pneumoniae is an opportunistic pathogen frequently associated with nosocomially acquired infections. Host cell adherence and biofilm formation of K. pneumoniae isolates is mediated by type 1 (T1P) and type 3 (MR/K) pili whose major fimbrial subunits are encoded by the fimA and mrkA genes, respectively. The E. coli common pilus (ECP) is an adhesive structure produced by all E. coli pathogroups and a homolog of the ecpABCDE operon is present in the K. pneumoniae genome. In this study, we aimed to determine the prevalence of these three fimbrial genes among a collection of 69 clinical and environmental K. pneumoniae strains and to establish a correlation with fimbrial production during cell adherence and biofilm formation. The PCR-based survey demonstrated that 96% of the K. pneumoniae strains contained ecpA and 94% of these strains produced ECP during adhesion to cultured epithelial cells. Eighty percent of the strains forming biofilms on glass produced ECP, suggesting that ECP is required, at least in vitro, for expression of these phenotypes. The fim operon was found in 100% of the strains and T1P was detected in 96% of these strains. While all the strains examined contained mrkA, only 57% of them produced MR/K fimbriae, alone or together with ECP. In summary, this study highlights the ability of K. pneumoniae strains to produce ECP, which may represent a new important adhesive structure of this organism. Further, it defines the multi-fimbrial nature of the interaction of this nosocomial pathogen with host epithelial cells and inert surfaces. PMID:23302788

  1. Multi-functional analysis of Klebsiella pneumoniae fimbrial types in adherence and biofilm formation.

    PubMed

    Alcántar-Curiel, María D; Blackburn, Dana; Saldaña, Zeus; Gayosso-Vázquez, Catalina; Iovine, Nicole M; De la Cruz, Miguel A; Girón, Jorge A

    2013-02-15

    Klebsiella pneumoniae is an opportunistic pathogen frequently associated with nosocomially acquired infections. Host cell adherence and biofilm formation of K. pneumoniae isolates is mediated by type 1 (T1P) and type 3 (MR/K) pili whose major fimbrial subunits are encoded by the fimA and mrkA genes, respectively. The E. coli common pilus (ECP) is an adhesive structure produced by all E. coli pathogroups and a homolog of the ecpABCDE operon is present in the K. pneumoniae genome. In this study, we aimed to determine the prevalence of these three fimbrial genes among a collection of 69 clinical and environmental K. pneumoniae strains and to establish a correlation with fimbrial production during cell adherence and biofilm formation. The PCR-based survey demonstrated that 96% of the K. pneumoniae strains contained ecpA and 94% of these strains produced ECP during adhesion to cultured epithelial cells. Eighty percent of the strains forming biofilms on glass produced ECP, suggesting that ECP is required, at least in vitro, for expression of these phenotypes. The fim operon was found in 100% of the strains and T1P was detected in 96% of these strains. While all the strains examined contained mrkA, only 57% of them produced MR/K fimbriae, alone or together with ECP. In summary, this study highlights the ability of K. pneumoniae strains to produce ECP, which may represent a new important adhesive structure of this organism. Further, it defines the multi-fimbrial nature of the interaction of this nosocomial pathogen with host epithelial cells and inert surfaces. PMID:23302788

  2. Treatment Adherence in Adolescents With Inflammatory Bowel Disease: The Collective Impact of Barriers to Adherence and Anxiety/Depressive Symptoms

    PubMed Central

    Gray, Wendy N.; Denson, Lee A.; Baldassano, Robert N.

    2012-01-01

    Objective Knowledge of factors impacting adolescents’ ability to adhere to their inflammatory bowel disease (IBD) regimen is limited. The current study examines the collective impact of barriers to adherence and anxiety/depressive symptoms on adolescent adherence to the IBD regimen. Methods Adolescents (n = 79) completed measures of barriers to adherence, adherence, and anxiety/depressive symptoms at one of two specialty pediatric IBD clinics. Results Most adolescents reported barriers to adherence and 1 in 8 reported borderline or clinically elevated levels of anxiety/depressive symptoms. Anxiety/depressive symptoms moderated the relationship between barriers to adherence and adherence. Post hoc probing revealed a significant, additive effect of higher anxiety/depressive symptoms in the barriers–adherence relationship, with adherence significantly lower among adolescents with higher barriers and higher anxiety/depressive symptoms. Conclusions In order to optimize adherence in adolescents, interventions should target not only barriers to adherence but also any anxiety/depressive symptoms that may negatively impact efforts to adhere to recommended treatment. PMID:22080456

  3. Mechanism of the Adherence of Streptococcus mutans to Smooth Surfaces III. Purification and Properties of the Enzyme Complex Responsible for Adherence.

    PubMed

    Mukasa, H; Slade, H D

    1974-11-01

    Enzymes which possess the ability to cause the adherence of Streptococcus mutans cells to a smooth glass surface were purified 1,100 times by chromatography on agarose gel followed by hydroxylapatite gel. During the purification procedures, the enzymes from strain HS6 (group a) were examined for the synthesis of water-soluble and water-insoluble polysaccharide and the ability to produce adherence. The enzyme preparations producing adherence of the S. mutans cells in the presence of sucrose possessed a molecular size of about 400,000 to 2,000,000 and were composed of approximately equivalent amounts of dextran and levan sucrases and 5 to 30% polysaccharide. The most highly purified preparation contained a negligible amount of contaminating protein as judged by polyacrylamide gel electrophoresis, immunoelectrophoresis, and gel diffusion. In these three tests, the location of the enzyme responsible for the synthesis of insoluble polymer was detected by embedding or covering the enzyme-containing gel with a layer of sucrose-containing agarose gel and observing the formation of insoluble polymer. During purification the ability of all fractions to produce adherence was parallel with the enzyme activity responsible for the synthesis of insoluble polysaccharide from sucrose. About two-thirds of the sucrase enzyme complex in the S. mutans culture fluid synthesized water-soluble polymer. This complex, obtained by filtration through agarose gel, was smaller in molecular size, lower in sugar content, and did not produce adherence, in contrast to the enzyme complex which possessed adherence activity. The inhibition of the enzyme complex synthesizing soluble polymer required more anti-synthetase serum than that required to inhibit the synthesis of water-insoluble polymer. It is not known whether the lack of adherence activity in this enzyme was due to its smaller size and lower sugar content or the absence of unknown factors which are essential for its activity. The

  4. Control network for monitoring deformation of slope by using optical measurements and FBG sensors

    NASA Astrophysics Data System (ADS)

    Li, C.; Liu, H.; Wang, Z.; Li, Y. N.; Chen, Y.; Xu, X. P.; Xu, J. C.

    2011-11-01

    The ground deformation observation is the method that estimates the ground deformation according to the displacement change of work spot measured periodically. By using the repeatability of the mechanical transducer and the reliability of the wavelength modulation, the differential fiber Bragg grating settlement gauge reduces availably the disturbance of the artificial causation and the weather. In this scheme, the drive rod converts the displacement of settlement block into the strain of beam, and causes the Bragg wavelength shifts of the sensing gratings mounted on the top and bottom surfaces of the beam, on which the temperature-compensated is achieved by the differential operation of the shifts of Bragg wavelengths. Because the collapse of slope is caused by the cutting slippage as the shearing strength in the soil body of slope exceeded the anti-shearing intensity, the slide prevention pier is the regular retaining structure for treating slope. The differential fiber Bragg grating settlement gauge is developed and fixed on the pier, which converts the settlement of the observation point into the Bragg wavelength shifts of the sensing gratings. Applied in Bai Ni-jing Slope, the measurement precision between the settlement gauges and Wild N3 precise level is 0.03, which is satisfied with the engineering order measure precision 0.05~0.1. By subtract the displacement-induced settlement deviation, the corrected precision between the settlement gauges compensated by Leica J2 theodolite and the precise level is improved to 0.007, which is satisfied with the scientific research order measure precision 0.01~0.05.

  5. Overactive bladder: strategies to ensure treatment compliance and adherence

    PubMed Central

    Dhaliwal, Prabhpreet; Wagg, Adrian

    2016-01-01

    Overactive bladder is a common, debilitating condition for many patients who may benefit from pharmacological management of their condition. However, adherence to medication in this condition is markedly worse than other chronic medical conditions. This review explores what is known about persistence and the factors which influence medication adherence for overactive bladder, those factors that might be modifiable to improve adherence, and the measures the health care provider can take to optimize adherence to therapy and thereby improve treatment outcomes. PMID:27350744

  6. Improved assay for quantitating adherence of ruminal bacteria to cellulose.

    PubMed Central

    Rasmussen, M A; White, B A; Hespell, R B

    1989-01-01

    A quantitative technique suitable for the determination of adherence of ruminal bacteria to cellulose was developed. This technique employs adherence of cells to cellulose disks and alleviates the problem of nonspecific cell entrapment within cellulose particles. By using this technique, it was demonstrated that the adherence of Ruminococcus flavefaciens FD1 to cellulose was inhibited by formaldehyde, methylcellulose, and carboxymethyl cellulose. Adherence was unaffected by acid hydrolysates of methylcellulose, glucose, and cellobiose. PMID:2782879

  7. Understanding how adherence goals promote adherence behaviours: a repeated measure observational study with HIV seropositive patients

    PubMed Central

    2012-01-01

    Background The extent to which patients follow treatments as prescribed is pivotal to treatment success. An exceptionally high level (> 95%) of HIV medication adherence is required to suppress viral replication and protect the immune system and a similarly high level (> 80%) of adherence has also been suggested in order to benefit from prescribed exercise programmes. However, in clinical practice, adherence to both often falls below the desirable level. This project aims to investigate a wide range of psychological and personality factors that may lead to adherence/non-adherence to medical treatment and exercise programmes. Methods HIV positive patients who are referred to the physiotherapist-led 10-week exercise programme as part of the standard care are continuously recruited. Data on social cognitive variables (attitude, intention, subjective norms, self-efficacy, and outcome beliefs) about the goal and specific behaviours, selected personality factors, perceived quality of life, physical activity, self-reported adherence and physical assessment are collected at baseline, at the end of the exercise programme and again 3 months later. The project incorporates objective measures of both exercise (attendance log and improvement in physical measures such as improved fitness level, weight loss, improved circumferential anthropometric measures) and medication adherence (verified by non-invasive hair analysis). Discussion The novelty of this project comes from two key aspects, complemented with objective information on exercise and medication adherence. The project assesses beliefs about both the underlying goal such as following prescribed treatment; and about the specific behaviours such as undertaking the exercise or taking the medication, using both implicit and explicit assessments of patients’ beliefs and attitudes. We predict that i) the way people think about the underlying goal of their treatments explains medication and exercise behaviours over and above

  8. Measuring adherence to treatment of paediatric HIV/AIDS.

    PubMed

    Naar-King, S; Frey, M; Harris, M; Arfken, C

    2005-04-01

    Parent, child, physician report and pill counts were used to measure adherence in paediatric HIV. Relationships to viral load were assessed. Pill counts were considered invalid. Adherence measures did not correlate with one another. Physicians reported lower adherence than parents, but parent and physician report correlated with viral load. The clinical and research utility of the various measures are discussed.

  9. A Matter of Trust: Patient Barriers to Primary Medication Adherence

    ERIC Educational Resources Information Center

    Polinski, J. M.; Kesselheim, A. S.; Frolkis, J. P.; Wescott, P.; Allen-Coleman, C.; Fischer, M. A.

    2014-01-01

    Primary medication adherence occurs when a patient properly fills the first prescription for a new medication. Primary adherence only occurs about three-quarters of the time for antihypertensive medications. We assessed patients' barriers to primary adherence and attributes of patient-provider discussions that might improve primary adherence…

  10. Medication Adherence in Psychopharmacologically Treated Adults with ADHD

    ERIC Educational Resources Information Center

    Safren, Steven A.; Duran, Petra; Yovel, Iftah; Perlman, Carol A.; Sprich, Susan

    2007-01-01

    Objective: One of the potential causes of residual symptoms of ADHD in adults can be difficulties with consistent adherence to medications. Method: This formative study examined self-reported medication adherence in adults with ADHD with clinically significant symptoms despite medication treatment. Results: Mean adherence for the two-week period…

  11. Medication Adherence among Older Adults with Schizophrenia

    PubMed Central

    Leutwyler, Heather C.; Fox, Patrick J.; Wallhagen, Margaret

    2014-01-01

    Older adults with schizophrenia are a growing segment of the population yet their physical and mental health status is extremely poor. The paper presents findings from a qualitative study that explored the understanding older adults with schizophrenia have of their physical health status. The study was conducted among 28 older adults with schizophrenia from a variety of settings using semi-structured interviews and participant observation. Self-management of psychiatric and non-psychiatric medications and its affect on their health status was one of the central themes that emerged from the study. Different styles of medication adherence were identified and factors associated with each style are presented. The findings provide insights into the design of clinical interventions aimed at promoting medication adherence among older adults with schizophrenia. PMID:23327119

  12. Subpopulations in purified platelets adhering on glass.

    PubMed

    Donati, Alessia; Gupta, Swati; Reviakine, Ilya

    2016-01-01

    Understanding how platelet activation is regulated is important in the context of cardiovascular disorders and their management with antiplatelet therapy. Recent evidence points to different platelet subpopulations performing different functions. In particular, procoagulant and aggregating subpopulations have been reported in the literature in platelets treated with the GPVI agonists. How the formation of platelet subpopulations upon activation is regulated remains unclear. Here, it is shown that procoagulant and aggregating platelet subpopulations arise spontaneously upon adhesion of purified platelets on clean glass surfaces. Calcium ionophore treatment of the adhering platelets resulted in one platelet population expressing both the procoagulant and the adherent population markers phosphatidylserine and the activated form of GPIIb/IIIa, while all of the platelets expressed CD62P independently of the ionophore treatment. Therefore, all platelets have the capacity to express all three activation markers. It is concluded that platelet subpopulations observed in various studies reflect the dynamics of the platelet activation process. PMID:27338300

  13. Medication adherence among older adults with schizophrenia.

    PubMed

    Leutwyler, Heather C; Fox, Patrick J; Wallhagen, Margaret

    2013-02-01

    Older adults with schizophrenia are a growing segment of the population, yet their physical and mental health status is extremely poor. This article presents findings from a qualitative study that explored the understanding older adults with schizophrenia have of their physical health status. The study was conducted among 28 older adults with schizophrenia from a variety of settings using semi-structured interviews and participant observation. Self-management of psychiatric and non-psychiatric medications and its effect on participants' health status was one of the central themes that emerged from the study. Different styles of medication adherence were identified and factors associated with each style are presented. The findings provide insights into the design of clinical interventions aimed at promoting medication adherence among older adults with schizophrenia.

  14. Ethics in adherence promotion and monitoring.

    PubMed

    Rand, C S; Sevick, M A

    2000-10-01

    In evaluating and intervening to increase adherence to medical treatments, clinicians and researchers must address ethical issues pertaining to best interest, autonomy, and privacy. "Best interest" refers to the notion that health-care practitioners act in a manner that produces benefits or good outcomes for the patients in their care. "Autonomy" refers to the patient's right to determine whether or not they will accept medical treatment or participate in a clinical study. "Nonmaleficence" refers to the clinician's or researcher's responsibility to "do no harm." "Privacy" refers to the notion that researchers and clinicians promise not to divulge personal information about the patients in their care. Adherence monitoring and promotion pose ethical challenges to researchers and clinicians, which are the topic of this paper. Control Clin Trials 2000;21:241S-247S

  15. Export of Extracellular Polysaccharides Modulates Adherence of the Cyanobacterium Synechocystis

    PubMed Central

    Fisher, Michael L.; Allen, Rebecca; Luo, Yingqin; Curtiss, Roy

    2013-01-01

    The field of cyanobacterial biofuel production is advancing rapidly, yet we know little of the basic biology of these organisms outside of their photosynthetic pathways. We aimed to gain a greater understanding of how the cyanobacterium Synechocystis PCC 6803 (Synechocystis, hereafter) modulates its cell surface. Such understanding will allow for the creation of mutants that autoflocculate in a regulated way, thus avoiding energy intensive centrifugation in the creation of biofuels. We constructed mutant strains lacking genes predicted to function in carbohydrate transport or synthesis. Strains with gene deletions of slr0977 (predicted to encode a permease component of an ABC transporter), slr0982 (predicted to encode an ATP binding component of an ABC transporter) and slr1610 (predicted to encode a methyltransferase) demonstrated flocculent phenotypes and increased adherence to glass. Upon bioinformatic inspection, the gene products of slr0977, slr0982, and slr1610 appear to function in O-antigen (OAg) transport and synthesis. However, the analysis provided here demonstrated no differences between OAg purified from wild-type and mutants. However, exopolysaccharides (EPS) purified from mutants were altered in composition when compared to wild-type. Our data suggest that there are multiple means to modulate the cell surface of Synechocystis by disrupting different combinations of ABC transporters and/or glycosyl transferases. Further understanding of these mechanisms may allow for the development of industrially and ecologically useful strains of cyanobacteria. Additionally, these data imply that many cyanobacterial gene products may possess as-yet undiscovered functions, and are meritorious of further study. PMID:24040267

  16. Concordance of adherence measurement using self-reported adherence questionnaires and medication monitoring devices.

    PubMed

    Shi, Lizheng; Liu, Jinan; Koleva, Yordanka; Fonseca, Vivian; Kalsekar, Anupama; Pawaskar, Manjiri

    2010-01-01

    The primary objective of this review was to identify and examine the literature on the association between medication adherence self-reported questionnaires (SRQs) and medication monitoring devices. The primary literature search was performed for 1980-2009 using PubMed, PubMed In Process and Non-Indexed, Ovid MEDLINE, Ovid MEDLINE In-Process, PsycINFO (EBSCO), CINAHL (EBSCO), Ovid HealthStar, EMBASE (Elsevier) and Cochrane Databases and using the following search terms: 'patient compliance', 'medication adherence', 'treatment compliance', 'drug monitoring', 'drug therapy', 'electronic', 'digital', 'computer', 'monitor', 'monitoring', 'drug', 'drugs', 'pharmaceutical preparations', 'compliance' and 'medications'. We identified studies that included SRQs and electronic monitoring devices to measure adherence and focused on the SRQs that were found to be moderately to highly correlated with the monitoring devices. Of the 1679 citations found via the primary search, 41 full-text articles were reviewed for correlation between monitoring devices and SRQs. A majority (68%) of articles reported high (27%), moderate (29%) or significant (12%) correlation between monitoring devices (37 using Medication Event Monitoring System [MEMS®] and four using other devices) and SRQs (11 identified and numerous other unnamed SRQs). The most commonly used SRQs were the Adult/Pediatric AIDS Clinical Trial Group (AACTG/PACTG; 24.4%, 10/41) followed by the 4-item Morisky (9.8%, 4/41), Brief Medication Questionnaire (9.8%, 4/41) and visual analogue scale (VAS; 7.3%, 3/41). Although study designs differed across the articles, SRQs appeared to report a higher rate of medication adherence (+14.9%) than monitoring devices. In conclusion, several medication adherence SRQs were validated using electronic monitoring devices. A majority of them showed high or moderate correlation with medication adherence measured using monitoring devices, and could be considered for measuring patient

  17. Adherence with drug therapy in the rheumatic diseases Part one: a review of adherence rates.

    PubMed

    Hill, Jackie

    2005-01-01

    Drug therapy plays a major role in the management of many rheumatic diseases and is particularly important in rheumatoid arthritis (RA) because of the significant rates of morbidity and mortality (Pincus, 1995). Understanding of the pathogenesis of RA has led to the development of new and more effective drugs (Emery et al., 1999), but the ultimate efficacy of any drug therapy depends upon the patient's decision to take it. There is widespread agreement that many people with rheumatic disease do not adhere to their medication regimens (Deyo et al., 1981; Belcon et al., 1984; Pullar et al., 1988; Hill et al., 2001). Research has demonstrated that 50% of women taking hormone replacement therapy for the prevention of osteoporosis discontinue treatment after a year (Fordham, 2000) and similar rates of discontinuation are found in other chronic diseases (Haynes et al., 1996, 2000). This is bewildering as, in asymptomatic illnesses such as hypertension and diabetes, the expectation is that levels of adherence would be lower than in diseases where pain and stiffness are present. The picture becomes even more confusing when we consider the findings from a recent multi-country study of RA, which found no association between adherence and disease severity, nor with the treatment prescribed (Viller et al., 1999). In chronic disease poor adherence is commonplace. The World Health Organization (WHO) recognizes this and has recently stated that 'poor adherence to treatment of chronic diseases is a worldwide problem of striking magnitude' and cites adherence to long-term therapy for chronic illnesses in developed countries averaging just 50% (WHO, 2003). The first part of this two part review focuses on adherence with drug therapy, and the second part discusses different methods of measuring it. PMID:17041995

  18. Adherence ability of Staphylococcus epidermidis on prosthetic biomaterials: an in vitro study.

    PubMed

    Shida, Takayuki; Koseki, Hironobu; Yoda, Itaru; Horiuchi, Hidehiko; Sakoda, Hideyuki; Osaki, Makoto

    2013-01-01

    Bacterial adhesion to the surface of biomaterials is an essential step in the pathogenesis of implant-related infections. In this in vitro research, we evaluated the ability of Staphylococcus epidermidis to adhere to the surface of solid biomaterials, including oxidized zirconium-niobium alloy (Oxinium), cobalt-chromium-molybdenum alloy, titanium alloy, commercially pure titanium, and stainless steel, and performed a biomaterial-to-biomaterial comparison. The test specimens were physically analyzed to quantitatively determine the viable adherent density of the S. epidermidis strain RP62A (American Type Culture Collection [ATCC] 35984). Field emission scanning electron microscope and laser microscope examination revealed a featureless, smooth surface in all specimens (average roughness <10 nm). The amounts of S. epidermidis that adhered to the biomaterial were significantly lower for Oxinium and the cobalt-chromium-molybdenum alloy than for commercially pure titanium. These results suggest that Oxinium and cobalt-chromium-molybdenum alloy are less susceptible to bacterial adherence and are less inclined to infection than other materials of a similar degree of smoothness.

  19. Campylobacter jejuni: components for adherence to and invasion of eukaryotic cells.

    PubMed

    Lugert, Raimond; Gross, Uwe; Zautner, Andreas E

    2015-01-01

    Campylobacter (C.) jejuni is the most important reported cause for bacterial diarrhoea. The infection can be accompanied by fever and abdominal cramps and in rare cases the Guillain-Barré syndrome or reactive arthritis can develop as a post-infection complication. Several biological properties of Cjejuni, e. g. motility and chemotaxis, contribute to the biological fitness of the pathogen. For this, deficiencies in the function of these features clearly reduce the pathogenicity of C. jejuni without being a virulence factor per se. Opposing to this, there are two essential requirements to determine the virulence of C. jejuni which represent the adherence to, and the invasion of host cells. Thereby, adherence, as a virulence factor, is mediated by many different bacterial-derived components like proteins but also by several oligo- and polysaccharide structures that are linked to surface proteins but also to the flagella. In addition, several invasion-relevant features of C. jejuni have been detected so far. Whereas some of them are described functionally to modulate cytoskeleton arrangement of the host cell, others are only described as invasion relevant. Indeed, investigations with respect to the pathogenic potential of some adherence- and invasion-relevant components did not give identical results indicating that their relevance might depend on the interplay of the respective C. jejuni strains used in these studies with the corresponding host cells. This review summarizes the C. jejuni components for adherence to and invasion of host cells together with their particular mode of action if known.

  20. Contribution of Spores to the Ability of Clostridium difficile To Adhere to Surfaces

    PubMed Central

    Joshi, Lovleen Tina; Phillips, Daniel S.; Williams, Catrin F.; Alyousef, Abdullah

    2012-01-01

    Clostridium difficile is the commonest cause of hospital-acquired infection in the United Kingdom. We characterized the abilities of 21 clinical isolates to form spores; to adhere to inorganic and organic surfaces, including stainless steel and human adenocarcinoma cells; and to germinate. The composition of culture media had a significant effect on spore formation, as significantly more spores were produced in brain heart infusion broth (Student's t test; P = 0.018). The spore surface relative hydrophobicity (RH) varied markedly (14 to 77%) and was correlated with the ability to adhere to stainless steel. We observed no correlation between the ribotype and the ability to adhere to steel. When the binding of hydrophobic (DS1813; ribotype 027; RH, 77%) and hydrophilic (DS1748; ribotype 002; RH, 14%) spores to human gut epithelial cells at different stages of cell development was examined, DS1813 spores adhered more strongly, suggesting the presence of surface properties that aid attachment to human cells. Electron microscopy studies revealed the presence of an exosporium surrounding DS1813 spores that was absent from spores of DS1748. Finally, the ability of spores to germinate was found to be strain and medium dependent. While the significance of these findings to the disease process has yet to be determined, this study has highlighted the importance of analyzing multiple isolates when attempting to characterize the behavior of a bacterial species. PMID:22923404

  1. In vitro evaluation of the impact of silver coating on Escherichia coli adherence to urinary catheters

    PubMed Central

    Ogilvie, Adam T.; Brisson, Brigitte A.; Singh, Ameet; Weese, J. Scott

    2015-01-01

    A silver-coated urinary catheter was compared to a non-silver-coated urinary catheter for the ability to reduce adherence of 6 isolates of Escherichia coli. Catheters were incubated with E. coli strains for 0, 24, 48, and 72 h. Broth was sampled at all time points to determine CFU/mL. Catheters were subjected to sonication to determine adhered bacteria at all time points, and scanning electron microscopy (SEM) to semi-quantitatively assess biofilm formation. Silver-coated catheters had significantly less adhered bacteria than non-silver-coated catheters at times 24, 48, and 72 h. Subjectively, silver-coated urinary catheters had less biofilm formation than non-silver-coated urinary catheters as assessed by SEM. Silver coating of catheters was associated with reduced adherence of E. coli in an in vitro evaluation. Testing of catheters in dogs in vivo is required to determine if there is a reduction in catheter-associated urinary tract infections. PMID:25969583

  2. Adherence ability of Staphylococcus epidermidis on prosthetic biomaterials: an in vitro study

    PubMed Central

    Shida, Takayuki; Koseki, Hironobu; Yoda, Itaru; Horiuchi, Hidehiko; Sakoda, Hideyuki; Osaki, Makoto

    2013-01-01

    Bacterial adhesion to the surface of biomaterials is an essential step in the pathogenesis of implant-related infections. In this in vitro research, we evaluated the ability of Staphylococcus epidermidis to adhere to the surface of solid biomaterials, including oxidized zirconium-niobium alloy (Oxinium), cobalt-chromium-molybdenum alloy, titanium alloy, commercially pure titanium, and stainless steel, and performed a biomaterial-to-biomaterial comparison. The test specimens were physically analyzed to quantitatively determine the viable adherent density of the S. epidermidis strain RP62A (American Type Culture Collection [ATCC] 35984). Field emission scanning electron microscope and laser microscope examination revealed a featureless, smooth surface in all specimens (average roughness <10 nm). The amounts of S. epidermidis that adhered to the biomaterial were significantly lower for Oxinium and the cobalt-chromium-molybdenum alloy than for commercially pure titanium. These results suggest that Oxinium and cobalt-chromium-molybdenum alloy are less susceptible to bacterial adherence and are less inclined to infection than other materials of a similar degree of smoothness. PMID:24143100

  3. Strain and damage monitoring in solar-powered aircraft composite wing using fiber Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Hyun; Lee, Kun-Ho; Ahn, Byung-Jun; Lee, Jin-Hyuk; Cheong, Seong-Kyun; Choi, Ik-Hyeon

    2013-04-01

    A solar powered aircraft is operated by converting solar energy into electrical energy. The wing of the solar powered aircraft requires a wide area to attach a number of solar cells in order to collect a large amount of solar energy. But the structural deformation and damage of the aircraft wing may occur because of bending and torsional loads induced by aerodynamic force during the operation. Therefore, the structural health monitoring of the wing is needed for increasing the operating time of the aircraft. In this study, the strain and damage of a composite wing of a solar powered aircraft were monitored by using fiber optic sensors until failure occurrence. In detail, a static loading experiment was performed on the composite wing with a length of 3.465m under a solar simulation environment, and the strain and acoustic emission (AE) of fracture signal were monitored by using fiber Bragg grating (FBG) sensors. In the results of the structural experiment, the damage occurred at a stringer when 4.5G load was applied to the composite wing, and the strain variations and AE signals were successfully measured by using FBG sensors. As a result, it is verified that the damage occurrence and location could be estimated by analyzing the strain variations and AE signals, and the fiber optic sensor would be a good transducer to monitor the structural status of a solar powered aircraft.

  4. Measurement of adherent cell mass and growth

    PubMed Central

    Park, Kidong; Millet, Larry J.; Kim, Namjung; Li, Huan; Jin, Xiaozhong; Popescu, Gabriel; Aluru, N. R.; Hsia, K. Jimmy; Bashir, Rashid

    2010-01-01

    The characterization of physical properties of cells such as their mass and stiffness has been of great interest and can have profound implications in cell biology, tissue engineering, cancer, and disease research. For example, the direct dependence of cell growth rate on cell mass for individual adherent human cells can elucidate the mechanisms underlying cell cycle progression. Here we develop an array of micro-electro-mechanical systems (MEMS) resonant mass sensors that can be used to directly measure the biophysical properties, mass, and growth rate of single adherent cells. Unlike conventional cantilever mass sensors, our sensors retain a uniform mass sensitivity over the cell attachment surface. By measuring the frequency shift of the mass sensors with growing (soft) cells and fixed (stiff) cells, and through analytical modeling, we derive the Young’s modulus of the unfixed cell and unravel the dependence of the cell mass measurement on cell stiffness. Finally, we grew individual cells on the mass sensors and measured their mass for 50+ hours. Our results demonstrate that adherent human colon epithelial cells have increased growth rates with a larger cell mass, and the average growth rate increases linearly with the cell mass, at 3.25%/hr. Our sensitive mass sensors with a position-independent mass sensitivity can be coupled with microscopy for simultaneous monitoring of cell growth and status, and provide an ideal method to study cell growth, cell cycle progression, differentiation, and apoptosis. PMID:21068372

  5. Adherence to asthma guidelines in general practices.

    PubMed

    Roghmann, M C; Sexton, M

    1999-06-01

    Adherence to asthma practice guidelines is low. Improved compliance could potentially improve care of patients with asthma. The purpose of this study was to determine if patients managed in a general practice with an associated asthma clinic are more likely to use asthma medications according to clinical practice guidelines than patients managed in the general surgery of the practice. A cross-sectional study of adult asthmatics, aged 18-55 years, was conducted in six British general practices. Prescription data on all asthma medication was collected for a 6-month period. Information on asthma clinic attendance, age, sex, employment status, other medical illness, and how patients used their inhaled beta2-agonist was collected through questionnaire. The prescription data for asthma medication and patient use of inhaled beta2-agonist were compared to the British Thoracic Society's (BTS) Guidelines for Management of Asthma in Adults to determine if the patient's asthma medication regimen was appropriate. There was no significant association found between appropriate asthma medication and asthma clinic attendance or other patient characteristics. Adherence to the BTS guidelines was low. Fifty-eight percent of the asthma patients used asthma medication regimens that were not consistent with the BTS guidelines published 1 year earlier. Adherence to the BTS guidelines was low regardless of patient characteristics, including asthma clinic attendance, age, sex, employment status, other medical illness, or individual practice. These findings underscore the need to document the utility of clinical practice guidelines which may improve physician compliance.

  6. Adherent Raindrop Modeling, Detectionand Removal in Video.

    PubMed

    You, Shaodi; Tan, Robby T; Kawakami, Rei; Mukaigawa, Yasuhiro; Ikeuchi, Katsushi

    2016-09-01

    Raindrops adhered to a windscreen or window glass can significantly degrade the visibility of a scene. Modeling, detecting and removing raindrops will, therefore, benefit many computer vision applications, particularly outdoor surveillance systems and intelligent vehicle systems. In this paper, a method that automatically detects and removes adherent raindrops is introduced. The core idea is to exploit the local spatio-temporal derivatives of raindrops. To accomplish the idea, we first model adherent raindrops using law of physics, and detect raindrops based on these models in combination with motion and intensity temporal derivatives of the input video. Having detected the raindrops, we remove them and restore the images based on an analysis that some areas of raindrops completely occludes the scene, and some other areas occlude only partially. For partially occluding areas, we restore them by retrieving as much as possible information of the scene, namely, by solving a blending function on the detected partially occluding areas using the temporal intensity derivative. For completely occluding areas, we recover them by using a video completion technique. Experimental results using various real videos show the effectiveness of our method.

  7. [Adherence to chronic medication: also a frequent problem in Belgium!].

    PubMed

    Liekens, S; Hulshagen, L; Dethier, M; Laekeman, G; Foulon, V

    2013-12-01

    Medication adherence in chronic conditions such as asthma, type 2 diabetes, heart failure, HIV and cancer appears to be a frequent problem. However, the literature on adherence in patients who use inhaled corticosteroids (ICS), oral hypoglycemic agents, drugs for heart failure, antiretrovirals or oral chemotherapy, contains little or no relevant data for Belgium. In the context of a Master thesis in Pharmaceutical care at KU Leuven, a quantitative study was performed to determine the prevalence of adherence to chronic medication in Belgium. This retrospective, cross-sectional study used a database containing refill data of a regional pharmacists' association (KLAV). Out of the 603 pharmacies affiliated with this association, all 50 pharmacies where HIV medication was delivered, were selected. Dispensing data from the selected pharmacies were collected from 01/07/2008 to 31/12/2009 for five pathologies, i.e.; asthma, type 2 diabetes, heart failure, HIV and cancer. Adherence (TT) was calculated with the Medication Refill Adherence (MRA) method. In order to determine whether there were associations between age, gender, drug class and adherence, Chi-square tests were used. Compared with the other patients, cancer patients were the most adherent in taking their drugs (median adherence rate = 88%). In addition, this was the only group in which the median adherence rate was above the set limit of 80%. The patients who were prescribed inhaled corticosteroids were the least adherent (median adherence rate = 38%). More than 50% of patients with asthma/COPD, heart failure and diabetes were classified as "under-users". Furthermore, the results showed a significant association within asthma patients between gender and adherence. In asthma, type 2 diabetes, heart failure and HIV patients there was a significant relationship between age and adherence and drug class and adherence. As the current study has some limitations, the results should be handled with caution. Nevertheless

  8. In Search of Multi-Peaked Reflective Spectrum with Optic Fiber Bragg Grating Sensor for Dynamic Strain Measurement

    NASA Technical Reports Server (NTRS)

    Tai, Hsiang

    2006-01-01

    In a typical optic fiber Bragg grating (FBG) strain measurement, unless in an ideal static laboratory environment, the presence of vibration or often disturbance always exists, which often creates spurious multiple peaks in the reflected spectrum, resulting in a non-unique determination of strain value. In this report we attempt to investigate the origin of this phenomenon by physical arguments and simple numerical simulation. We postulate that the fiber gratings execute small amplitude transverse vibrations changing the optical path in which the reflected light traverses slightly and non-uniformly. Ultimately, this causes the multi-peak reflected spectrum.

  9. Promoting adherence to nebulized therapy in cystic fibrosis: poster development and a qualitative exploration of adherence

    PubMed Central

    Jones, Stephen; Babiker, Nathan; Gardner, Emma; Royle, Jane; Curley, Rachael; Hoo, Zhe Hui; Wildman, Martin J

    2015-01-01

    Background Cystic fibrosis (CF) health care professionals recognize the need to motivate people with CF to adhere to nebulizer treatments, yet little is known about how best to achieve this. We aimed to produce motivational posters to support nebulizer adherence by using social marketing involving people with CF in the development of those posters. Methods The Sheffield CF multidisciplinary team produced preliminary ideas that were elaborated upon with semi-structured interviews among people with CF to explore barriers and facilitators to the use of nebulized therapy. Initial themes and poster designs were refined using an online focus group to finalize the poster designs. Results People with CF preferred aspirational posters describing what could be achieved through adherence in contrast to posters that highlighted the adverse consequences of nonadherence. A total of 14 posters were produced through this process. Conclusion People with CF can be engaged to develop promotional material to support adherence, providing a unique perspective differing from that of the CF multidisciplinary team. Further research is needed to evaluate the effectiveness of these posters to support nebulizer adherence. PMID:26346635

  10. The old problem of adherence: research on treatment adherence and its relevance for HIV/AIDS.

    PubMed

    Wright, M T

    2000-12-01

    The international published research on patient adherence was selectively reviewed with the goal of determining its relevance for the treatment of HIV/AIDS. Results show that not adhering to treatment regimes is so widespread that no combination of sociodemographic variables is reliably predictive of patients' not following doctors' orders. Achieving 100% adherence for any treatment or patient group does not appear to be realistic. Characteristics of the patient's situation, of the given therapy, and of the disease itself affect adherence. In addition, the patient-doctor relationship and the context of the treatment are important. Often overlooked are the existential dimensions of meaning, self-determination and quality of life which are particularly important for the chronically ill. Treatment needs to be negotiated individually with each patient on the basis of an open therapeutic relationship and with the help of multidimensional interventions. Lessons from the discourse on safer sex can steer adherence research and practice away from a behavioural and reductionist approach toward the context and meaning of treatment. PMID:11177448

  11. The functions of the variable lipoprotein family of Mycoplasma hyorhinis in adherence to host cells.

    PubMed

    Xiong, Qiyan; Wang, Jia; Ji, Yan; Ni, Bo; Zhang, Bixiong; Ma, Qinghong; Wei, Yanna; Xiao, Shaobo; Feng, Zhixin; Liu, Maojun; Shao, Guoqing

    2016-04-15

    Mycoplasma hyorhinis (M. hyorhinis) is a swine pathogen that is associated with various human cancers and contamination in cell cultures. However, no studies on the adhesion molecules of this pathogen have yet been reported. The variable lipoprotein (Vlp) family is an important surface component of M. hyorhinis. Herein, we performed several experiments to identify the function of the Vlp family in adherence to host cells. Seven recombinant Vlp (rVlp) proteins were expressed in Escherichia coli and purified by affinity chromatography. The potential role of rVlp adherence to pig kidney (PK-15) and swine tracheal epithelial (STEC) cells was then studied by indirect immunofluorescence assay and microtiter plate adherence assay. Adhesion of M. hyorhinis to PK-15 and STEC cells was specifically inhibited by the addition of a cocktail of rVlp proteins. The rVlp protein mixture was shown to bind to both PK-15 and STEC cells. The binding increased in a dose-dependent manner and could be blocked by antisera against the rVlp proteins. Most of the rVlp proteins could bind individually to both PK-15 and STEC cells except for rVlpD and rVlpF, which bound only to STEC cells. Because Vlp members vary in size among different strains and generations, they may vary in their cytoadhesion capabilities in various strains. In summary, the present results indicate that the Vlp family functions as adhesins of M. hyorhinis. PMID:27016761

  12. Adherence of Candida albicans to a cell surface polysaccharide receptor on Streptococcus gordonii.

    PubMed Central

    Holmes, A R; Gopal, P K; Jenkinson, H F

    1995-01-01

    Candida albicans ATCC 10261 and CA2 bound to cells of the oral bacteria Streptococcus gordonii, Streptococcus oralis, and Streptococcus sanguis when these bacteria were immobilized onto microtiter plate wells, but they did not bind to cells of Streptococcus mutans or Streptococcus salivarius. Cell wall polysaccharide was extracted with alkali from S. gordonii NCTC 7869, the streptococcal species to which C. albicans bound with highest affinity, and was effective in blocking the coaggregation of C. albicans and S. gordonii cells in the fluid phase. When fixed to microtiter plate wells, the S. gordonii polysaccharide was bound by all strains of C. albicans tested. The polysaccharide contained Rha, Glc, GalNAc, GlcNAc, and Gal and was related compositionally to previously characterized cell wall polysaccharides from strains of S. oralis and S. sanguis. The adherence of yeast cells to the immobilized polysaccharide was not inhibitable by a number of saccharides. Antiserum raised to the S. gordonii NCTC 7869 polysaccharide blocked adherence of C. albicans ATCC 10261 to the polysaccharide. The results identify a complex cell wall polysaccharide of S. gordonii as the coaggregation receptor for C. albicans. Adherent interactions of yeast cells with streptococci and other bacteria may be important for colonization of both hard and soft oral surfaces by C. albicans. PMID:7729891

  13. Xylitol and erythritol decrease adherence of polysaccharide-producing oral streptococci.

    PubMed

    Söderling, Eva M; Hietala-Lenkkeri, Aija-Maaria

    2010-01-01

    Xylitol consumption decreases counts of mutans streptococci. However, the mechanism behind this decrease is not well understood. We studied not only type strains and clinical isolates of mutans streptococci, but also other polysaccharide-forming oral streptococci. Growth inhibition and adherence of cells to a smooth glass surface-reflecting synthesis of water-insoluble polysaccharides were studied in the presence of 2% (0.13 mol/l) and 4% (0.26 mol/l) xylitol. The effect of xylitol was compared to a novel polyol sweetener, erythritol. Except for Streptococcus mutans 10449 and S. sobrinus OMZ 176, the glass surface adhesion of most polysaccharide-forming streptococci was reduced by the presence of both 4% xylitol and erythritol. For the S. mutans and S. sobrinus type strains, the growth inhibition with 4% xylitol and erythritol was 36-77% and for the clinical S. mutans isolates 13-73%. Of the other oral streptococci, only S. sanguinis was inhibited with 4% xylitol (45-55%). For both polyols, the magnitude of the growth inhibition observed was not associated with the magnitude of the decrease in adherence (xylitol: r = -0.18; erythritol: r = 0.49). In conclusion, both xylitol and erythritol can decrease polysaccharide-mediated cell adherence contributing to plaque accumulation through a mechanism not dependent on growth inhibition.

  14. Urease prevents adherence of Helicobacter pylori to Kato III gastric epithelial cells.

    PubMed

    Makristathis, A; Rokita, E; Pasching, E; Apfalter, P; Willinger, B; Rotter, M L; Hirschl, A M

    2001-08-15

    The role of urease in Helicobacter pylori adherence to and internalization by Kato III cells was investigated. Kato III cells were incubated with wild-type strains (N6 or P1), with isogenic mutants lacking urease (N6ureB::TnKm or P1ureA::TnMax5) or producing the inactive apoprotein (N6ureG::TnKm), and with urease-positive clones recovered after complementation of N6ureB::TnKm with ureAB. Bacteria were stained with the green fluorescent dye PKH2, and the bacteria load of cells was analyzed by flow cytometry. With mutants lacking urease, the bacteria load was considerably increased, in comparison with the corresponding parental strains (P<.001). With clone K2(3), producing larger amounts of urease than N6, a significant reduction of bacteria load was observed, in comparison with the wild type (P<.001). N6ureG::TnKm showed adherence characteristics similar to those of N6. The role of urease in internalization was not clear. Thus, urease significantly inhibits H. pylori adherence to Kato III cells by a mechanism largely independent of enzymatic activity. PMID:11471101

  15. Adherence to diabetes medication in individuals with schizophrenia.

    PubMed

    Gorczynski, Paul; Patel, Hiren; Ganguli, Rohan

    2014-02-01

    Introduction: Despite the importance of medication adherence for the effective treatment of type II diabetes mellitus (T2DM), little research has examined adherence with diabetes medication treatment in schizophrenia. The purpose of this systematic review was to 1) evaluate rates of adherence and determinants of adherence with medication for T2DM in individuals with schizophrenia, and, where possible, 2) examine the relationship between medication adherence and glycemic control. Methods: Studies were included if they presented information on dosing regimens and adherence or compliance rates for T2DM and included samples where at least 50% of the participants were individuals with schizophrenia. Results: Six studies were included in this review that predominantly examined men over the age of 50 years. Studies confirmed that many individuals with schizophrenia were not adhering to their diabetes medication as adherence rates ranged from 51-85%. Two studies that compared medication adherence in individuals with and without schizophrenia found those with the mental illness had higher rates of adherence. One study reported that blood glucose control levels were not statistically different between those who did and did not adhere to their medication, indicating more research is necessary in this area. Factors that improved adherence included disease and medical service and medication related factors. Conclusions: Interventions to increase diabetes medication adherence in schizophrenia need to address disease and medical service and medication related factors. Further research needs to examine diabetes medication adherence in women, younger individuals, and those recently diagnosed with diabetes as these individuals have been underrepresented in the literature.

  16. Strain Gage

    NASA Technical Reports Server (NTRS)

    1995-01-01

    HITEC Corporation developed a strain gage application for DanteII, a mobile robot developed for NASA. The gage measured bending forces on the robot's legs and warned human controllers when acceptable forces were exceeded. HITEC further developed the technology for strain gage services in creating transducers out of "Indy" racing car suspension pushrods, NASCAR suspension components and components used in motion control.

  17. The effect of Nepeta cataria extract on adherence and enzyme production of Staphylococcus aureus.

    PubMed

    Nostro, A; Cannatelli, M A; Crisafi, G; Alonzo, V

    2001-12-01

    Nepeta cataria L., commonly known as catnip, is a perennial herb with a considerable folkloric reputation. A diethyl ether extract of this plant has been shown to have antimicrobial activity against fungi and Gram-positive bacteria. The aim of this work was to study the activity of N. cataria extract on 44 Staphylococcus aureus strains, some resistant to methicillin, and S. aureus 6538P (American Type Culture Collection) by evaluating the effect of subminimum inhibitory concentrations on coagulase, DNAse, thermonuclease and lipase production, and on in-vitro adherence. DNAse, thermonuclease and lipase were inhibited by concentrations equal to 1/2 and 1/4 MIC. A reduction of adherence was also observed.

  18. Anaerobic Conditions Promote Expression of Sfp Fimbriae and Adherence of Sorbitol-Fermenting Enterohemorrhagic Escherichia coli O157:NM to Human Intestinal Epithelial Cells▿

    PubMed Central

    Müsken, Anne; Bielaszewska, Martina; Greune, Lilo; Schweppe, Christian H.; Müthing, Johannes; Schmidt, Herbert; Schmidt, M. Alexander; Karch, Helge; Zhang, Wenlan

    2008-01-01

    The sfp gene cluster, unique to sorbitol-fermenting (SF) enterohemorrhagic Escherichia coli (EHEC) O157:NM strains, encodes fimbriae that mediate mannose-resistant hemagglutination in laboratory E. coli strains but are not expressed in wild-type SF EHEC O157:NM strains under standard laboratory conditions. We investigated whether Sfp fimbriae are expressed under conditions that mimic the intestinal environment and whether they contribute to the adherence of SF EHEC O157:NM strains to human intestinal epithelial cells. The transcription of sfpA (encoding the major fimbrial subunit) was upregulated in all strains investigated, and all expressed SfpA and possessed fimbriae that reacted with an anti-SfpA antibody when the strains were grown on solid media under anaerobic conditions. Sfp expression was absent under aerobic conditions and in liquid media. Sfp upregulation under anaerobic conditions was significantly higher on blood agar and a medium simulating the colonic environment than on a medium simulating the ileal environment (P < 0.05). The induction of Sfp fimbriae in SF E. coli O157:NM strains correlates with increased adherence to Caco-2 and HCT-8 cells. Our data indicate that the expression of Sfp fimbriae in SF E. coli O157:NM strains is induced under conditions resembling those of the natural site of infection and that Sfp fimbriae may contribute to the adherence of the organisms to human intestinal epithelium. PMID:18083855

  19. In-fiber Fabry-Perot interferometer for strain and magnetic field sensing.

    PubMed

    Costa, Greice K B; Gouvêa, Paula M P; Soares, Larissa M B; Pereira, João M B; Favero, Fernando; Braga, Arthur M B; Palffy-Muhoray, Peter; Bruno, Antonio C; Carvalho, Isabel C S

    2016-06-27

    In this paper we discuss the results obtained with an in-fiber Fabry-Perot interferometer (FPI) used in strain and magnetic field (or force) sensing. The intrinsic FPI was constructed by splicing a small section of a capillary optical fiber between two pieces of standard telecommunication fiber. The sensor was built by attaching the FPI to a magnetostrictive alloy in one configuration and also by attaching the FPI to a small magnet in another. Our sensors were found to be over 4 times more sensitive to magnetic fields and around 10 times less sensitive to temperature when compared to sensors constructed with Fiber Bragg Grating (FBG).

  20. Iterative matrix inversion technique for simultaneous strain and temperature sensing in an extended temperature range

    NASA Astrophysics Data System (ADS)

    Hopf, Barbara; Koch, Alexander W.; Roths, Johannes

    2016-05-01

    The linear matrix approach is the common method for multi-parameter FBG-based strain and temperature sensing. As it does not include non-linear temperature responses and hence lacks accuracy, the application of an iterative matrix inversion technique can be used to remedy this deficiency. Employing this method in a set-up using a multi-parameter sensor system that consists of two FBGs in fibers, which differ in cladding diameters, significantly reduced temperature uncertainties of +/- 1°C could be achieved within a temperature range between -20°C and 150°C.

  1. In-fiber Fabry-Perot interferometer for strain and magnetic field sensing.

    PubMed

    Costa, Greice K B; Gouvêa, Paula M P; Soares, Larissa M B; Pereira, João M B; Favero, Fernando; Braga, Arthur M B; Palffy-Muhoray, Peter; Bruno, Antonio C; Carvalho, Isabel C S

    2016-06-27

    In this paper we discuss the results obtained with an in-fiber Fabry-Perot interferometer (FPI) used in strain and magnetic field (or force) sensing. The intrinsic FPI was constructed by splicing a small section of a capillary optical fiber between two pieces of standard telecommunication fiber. The sensor was built by attaching the FPI to a magnetostrictive alloy in one configuration and also by attaching the FPI to a small magnet in another. Our sensors were found to be over 4 times more sensitive to magnetic fields and around 10 times less sensitive to temperature when compared to sensors constructed with Fiber Bragg Grating (FBG). PMID:27410621

  2. Topography Influences Adherent Cell Regulation of Osteoclastogenesis.

    PubMed

    Nagasawa, M; Cooper, L F; Ogino, Y; Mendonca, D; Liang, R; Yang, S; Mendonca, G; Uoshima, K

    2016-03-01

    The importance of osteoclast-mediated bone resorption in the process of osseointegration has not been widely considered. In this study, cell culture was used to investigate the hypothesis that the function of implant-adherent bone marrow stromal cells (BMSCs) in osteoclastogenesis is influenced by surface topography. BMSCs isolated from femur and tibia of Sprague-Dawley rats were seeded onto 3 types of titanium surfaces (smooth, micro, and nano) and a control surface (tissue culture plastic) with or without osteogenic supplements. After 3 to 14 d, conditioned medium (CM) was collected. Subsequently, rat bone marrow-derived macrophages (BMMs) were cultured in media supplemented with soluble receptor activator of NF-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) as well as BMSC CM from each of the 4 surfaces. Gene expression levels of soluble RANKL, osteoprotegerin, tumor necrosis factor α, and M-CSF in cultured BMSCs at different time points were measured by real-time polymerase chain reaction. The number of differentiated osteoclastic cells was determined after tartrate-resistant acid phosphatase staining. Analysis of variance and t test were used for statistical analysis. The expression of prominent osteoclast-promoting factors tumor necrosis factor α and M-CSF was increased by BMSCs cultured on both micro- and nanoscale titanium topographies (P < 0.01). BMSC CM contained a heat-labile factor that increased BMMs osteoclastogenesis. CM from both micro- and nanoscale surface-adherent BMSCs increased the osteoclast number (P < 0.01). Difference in surface topography altered BMSC phenotype and influenced BMM osteoclastogenesis. Local signaling by implant-adherent cells at the implant-bone interface may indirectly control osteoclastogenesis and bone accrual around endosseous implants. PMID:26553885

  3. The use of incentives to reinforce medication adherence

    PubMed Central

    DeFulio, Anthony; Silverman, Kenneth

    2012-01-01

    Objective Poor medication adherence is a longstanding problem, and is especially pertinent for individuals with chronic conditions or diseases. Adherence to medications can improve patient outcomes and greatly reduce the cost of care. The purpose of the present review is to describe the literature on the use of incentives as applied to the problem of medication adherence. Methods We conducted a systematic review of peer-reviewed empirical evaluations of incentives provided to patients contingent upon medication adherence. Results This review suggests that incentive-based medication adherence interventions can be very effective, but there are few controlled studies. The studies on incentive-based medication adherence interventions most commonly feature patients taking medication for drug or alcohol dependence, HIV, or latent tuberculosis. Across studies that reported percent adherence comparisons, incentives increased adherence by a mean of 20 percentage points, but effects varied widely. Cross-study comparisons indicate a positive relationship between the value of the incentive and the impact of the intervention. Post-intervention evaluations were rare, but tended to find that adherence effects diminish after the interventions are discontinued. Conclusions Incentive-based medication adherence interventions are promising but understudied. A significant challenge for research in this area is the development of sustainable and cost-effective long-term interventions. PMID:22580095

  4. Determinants of methotrexate adherence in rheumatoid arthritis patients.

    PubMed

    De Cuyper, Ellen; De Gucht, Veronique; Maes, Stan; Van Camp, Yoleen; De Clerck, Luc S

    2016-05-01

    In rheumatoid arthritis (RA) patients, weekly intake of methotrexate (MTX) is the basic drug treatment. This observational study aims to investigate how many RA patients are adherent in terms of MTX intake and to identify determinants of non-adherence. Intake of MTX (orally or via injection) was recorded in 129 RA patients with an electronic monitoring system (MEMS(®)) during 16 weeks. In addition, two adherence questionnaires, the Medication Adherence Report Scale (MARS-5) and the Compliance-Questionnaire-Rheumatology (CQR) as well as a visual analogue scale (VAS) measuring MTX adherence, were administered to these patients. As possible determinants of adherence, data on demographics, disease and treatment characteristics, depression, illness cognitions, motivation, and social support were collected. Of all participants, 58 % were fully adherent and 75 % skipped at most one dose during 16 weeks. A better mental health status and suffering from comorbidities had a positive effect on adherence, while living alone had a negative effect. These three predictors explained 30 % of the variance in MTX adherence. Of the three self-report medication adherence measures, the VAS correlated the highest with the results of the electronic monitoring system (r = 0.552, p = 0.01). A relatively high adherence rate was observed in RA patients treated with MTX. The determinants identified by this study could be used to screen patients at risk for non-adherence. A simple VAS scale seems to be an acceptable way for a preliminary screening of MTX adherence. PMID:26781783

  5. Medication adherence among transgender women living with HIV.

    PubMed

    Baguso, Glenda N; Gay, Caryl L; Lee, Kathryn A

    2016-08-01

    Medication adherence is linked to health outcomes among adults with HIV infection. Transgender women living with HIV (TWLWH) in the US report suboptimal adherence to medications and are found to have difficulty integrating HIV medication into their daily routine, but few studies explore the factors associated with medication adherence among transgender women. Thus, the purpose of this paper is to examine demographic and clinical factors related to self-reported medication adherence among transgender women. This secondary analysis is based on data collected from the Symptom and Genetic Study that included a convenience sample of 22 self-identified transgender women, 201 non-transgender men, and 72 non-transgender women recruited in northern California. Self-reported medication adherence was assessed using the AIDS Clinical Trials Group Adherence Questionnaire. Gender differences in demographic and clinical variables were assessed, as were differences between transgender women reporting high and low adherence. Transgender women had lower adherence to medications compared to non-transgender males and non-transgender females (p = .028) and were less likely to achieve viral suppression (p = .039). Within the transgender group, Black/African-Americans reported better adherence than participants who were Whites/Caucasian or other races (p = .009). Adherence among transgender women was unrelated to medication count and estrogen therapy, but consistent with other reports on the HIV population as a whole; transgender women with high adherence were more likely to achieve viral suppression compared to the transgender women with low adherence. Despite the high incidence of HIV infection in the transgender population, few studies focus on TWLWH, either in regard to their adherence to antiretroviral therapies or to their healthcare in general. To address ongoing health disparities, more studies are needed focusing on the transgender population's continuum of care in

  6. Patient adherence to medical treatment: a review of reviews

    PubMed Central

    van Dulmen, Sandra; Sluijs, Emmy; van Dijk, Liset; de Ridder, Denise; Heerdink, Rob; Bensing, Jozien

    2007-01-01

    Background Patients' non-adherence to medical treatment remains a persistent problem. Many interventions to improve patient adherence are unsuccessful and sound theoretical foundations are lacking. Innovations in theory and practice are badly needed. A new and promising way could be to review the existing reviews of adherence to interventions and identify the underlying theories for effective interventions. That is the aim of our study. Methods The study is a review of 38 systematic reviews of the effectiveness of adherence interventions published between 1990 and 2005. Electronic literature searches were conducted in Medline, Psychinfo, Embase and the Cochrane Library. Explicit inclusion and exclusion criteria were applied. The scope of the study is patient adherence to medical treatment in the cure and care sector. Results Significant differences in the effectiveness of adherence interventions were found in 23 of the 38 systematic reviews. Effective interventions were found in each of four theoretical approaches to adherence interventions: technical, behavioural, educational and multi-faceted or complex interventions. Technical solutions, such as a simplification of the regimen, were often found to be effective, although that does not count for every therapeutic regimen. Overall, our results show that, firstly, there are effective adherence interventions without an explicit theoretical explanation of the operating mechanisms, for example technical solutions. Secondly, there are effective adherence interventions, which clearly stem from the behavioural theories, for example incentives and reminders. Thirdly, there are other theoretical models that seem plausible for explaining non-adherence, but not very effective in improving adherence behaviour. Fourthly, effective components within promising theories could not be identified because of the complexity of many adherence interventions and the lack of studies that explicitly compare theoretical components

  7. Automated microinjection system for adherent cells

    NASA Astrophysics Data System (ADS)

    Youoku, Sachihiro; Suto, Yoshinori; Ando, Moritoshi; Ito, Akio

    2007-07-01

    We have developed an automated microinjection system that can handle more than 500 cells an hour. Microinjection injects foreign agents directly into cells using a micro-capillary. It can randomly introduce agents such as DNA, proteins and drugs into various types of cells. However, conventional methods require a skilled operator and suffer from low throughput. The new automated microinjection techniques we have developed consist of a Petri dish height measuring method and a capillary apex position measuring method. The dish surface height is measured by analyzing the images of cells that adhere to the dish surface. The contrast between the cell images is minimized when the focus plane of an object lens coincides with the dish surface. We have developed an optimized focus searching method with a height accuracy of +/-0.2 um. The capillary apex position detection method consists of three steps: rough, middle, and precise. These steps are employed sequentially to cover capillary displacements of up to +/-2 mm, and to ultimately accomplish an alignment accuracy of less than one micron. Experimental results using this system we developed show that it can introduce fluorescent material (Alexa488) into adherent cells, HEK293, with a success rate of 88.5%.

  8. Distribution and Phylogeny of Immunoglobulin-Binding Protein G in Shiga Toxin-Producing Escherichia coli and Its Association with Adherence Phenotypes▿

    PubMed Central

    Merkel, Viktor; Ohder, Barbara; Bielaszewska, Martina; Zhang, Wenlan; Fruth, Angelika; Menge, Christian; Borrmann, Erika; Middendorf, Barbara; Müthing, Johannes; Karch, Helge; Mellmann, Alexander

    2010-01-01

    eibG in Shiga toxin-producing Escherichia coli (STEC) O91 encodes a protein (EibG) which binds human immunoglobulins G and A and contributes to bacterial chain-like adherence to human epithelial cells. We investigated the prevalence of eibG among STEC, the phylogeny of eibG, and eibG allelic variations and their impact on the adherence phenotype. eibG was found in 15.0% of 240 eae-negative STEC strains but in none of 157 eae-positive STEC strains. The 36 eibG-positive STEC strains belonged to 14 serotypes and to eight multilocus sequence types (STs), with serotype O91:H14/H− and ST33 being the most common. Sequences of the complete eibG gene (1,527 bp in size) from eibG-positive STEC resulted in 21 different alleles with 88.11% to 100% identity to the previously reported eibG sequence; they clustered into three eibG subtypes (eibG-α, eibG-β, and eibG-γ). Strains expressing EibG-α and EibG-β displayed a mostly typical chain-like adherence pattern (CLAP), with formation of long chains on both human and bovine intestinal epithelial cells, whereas strains with EibG-γ adhered in short chains, a pattern we termed atypical CLAP. The same adherence phenotypes were displayed by E. coli BL21(DE3) clones containing the respective eibG-α, eibG-β, and eibG-γ subtypes. We propose two possible evolutionary scenarios for eibG in STEC: a clonal development of eibG in strains with the same phylogenetic background or horizontal transfer of eibG between phylogenetically unrelated STEC strains. PMID:20547747

  9. Side effects, adherence self-efficacy, and adherence to antiretroviral treatment: a mediation analysis in a Chinese sample.

    PubMed

    Zhang, Liying; Li, Xiaoming; Lin, Zhenping; Jacques-Tiura, Angela J; Xu, Jinping; Zhou, Yuejiao; Qiao, Shan; Shen, Zhiyong; Stanton, Bonita

    2016-07-01

    Antiretroviral therapy (ART) is a lifelong treatment. To date, ART adherence is suboptimal for most patients in resource-poor settings. Previous research indicates that medication side effects are perceived to be a significant barrier of high ART adherence. Data regarding the role of adherence self-efficacy in mediating the relationship between side effects from ART and adherence to ART are limited; thus, this study examines this potential mediational role of self-efficacy. A cross-sectional survey of 2987 people living with HIV aged ≥18 years was conducted in 2012-2013 in Guangxi Autonomous Region (Guangxi) which has one of the fastest-growing HIV rates in China. Of the total sample, 2146 (72.1%) participants had initiated ART. Participants reported the number of days of completing the daily dose of ART in the past month; adherence was defined as completing the daily dose at least 28 days in the last month (≥90%). Side effects were significantly negatively related to adherence to ART. Mediation analyses indicated that adherence self-efficacy significantly mediated the side effects-adherence relationship. Future interventions to increase adherence self-efficacy and effective coping with side effects among HIV patients are needed in order to improve their ART adherence.

  10. Challenges in measuring medication adherence: experiences from a controlled trial.

    PubMed

    Stewart, Kay; Mc Namara, Kevin P; George, Johnson

    2014-02-01

    Measurement of adherence is complex and many methods, both direct and indirect are used; there is no universal gold standard. In this article, we share our experiences in a randomised controlled study, the Hypertension Adherence Program in Pharmacy trial, evaluating a community pharmacy-based intervention for improving adherence to antihypertensive medication. Several objective and subjective measures of adherence (Morisky score, TABS score, MedsIndex, Medicines Possession Ratio) were used, but produced varying results, limiting confidence in the conclusions that could be drawn. Despite using a specifically designed data mining software program to identify potentially nonadherent patients from dispensing records, many participants were found to be adherent by the self reported Morisky scale. A lesson to be learned when targeting people for interventions to improve adherence is that information from dispensing records should be supplemented by other methods in order to identify patients most in need of assistance.

  11. [e-Health interventions and improvement in treatment adherence].

    PubMed

    Sieben, Angelien; Bredie, S J H Bas; van Laarhoven, C J H M Kees; Schoonhoven, Lisette; Burger, David M; van Onzenoort, Hein A W

    2014-01-01

    Poor adherence to medication is one of the most important determinants in the treatment of patients with chronic disorders. e-Health-based interventions may be able to improve treatment adherence. This article gives an overview of the available e-Health interventions and the extent to which they can improve adherence. We searched in the PubMed, Cinahl, PsycInfo, and Embase databases for e-Health interventions that aimed at improving adherence to treatment. Of the 16 included studies, 15 used a website and one used an app. Ten studies showed a significant improvement in treatment adherence by using the intervention. e-Health interventions were generally complex. Simple interventions were the most successful in improving treatment adherence.

  12. [Strategies for measuring medication adherence in patients with schizophrenia].

    PubMed

    Wang, Yunfang; Huang, Zhiping; Xu, Dong; Gong, Wenjie; Tang, Yuan; Xiao, Shuiyuan

    2016-02-01

    Long-term therapy should be administrated for patients with schizophrenia and the medication adherence is very important for the prognosis and outcome in these patients. In this study, we screened the literatures from various databases in accordance with our search criteria. A total of 11 literatures with the results of reliability and validity regarding the measurement of schizophrenia medication adherence were enrolled in our analysis. Based on the measurements, they were classified into subjective methods and objective ones. The objective methods include blood plasma and urine concentrations, pharmacy records, pill counts and Medication Event Monitoring System. The subjective methods include Drug Attitude Inventory, Rating of Medication Influences Scale, Brief Evaluation of Medication Influences and Beliefs, the Brief Adherence Rating Scale, Medication Adherence Rating Scale, and Morisky scales. In general, single method for measuring medication adherence in patients with schizophrenia is limited. We recommend researchers to use 2 or more methods when measuring the medication adherence in patients with schizophrenia.

  13. Enterotoxigenic Escherichia coli TibA Glycoprotein Adheres to Human Intestine Epithelial Cells

    PubMed Central

    Lindenthal, Christoph; Elsinghorst, Eric A.

    2001-01-01

    Enterotoxigenic Escherichia coli (ETEC) is capable of invading epithelial cell lines derived from the human ileum and colon. Two separate invasion loci (tia and tib) that direct noninvasive E. coli strains to adhere to and invade cultured human intestine epithelial cells have previously been isolated from the classical ETEC strain H10407. The tib locus directs the synthesis of TibA, a 104-kDa outer membrane glycoprotein. Synthesis of TibA is directly correlated with the adherence and invasion phenotypes of the tib locus, suggesting that this protein is an adhesin and invasin. Here we report the purification of TibA and characterization of its biological activity. TibA was purified by continuous-elution preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purified TibA was biotin labeled and then shown to bind to HCT8 human ileocecal epithelial cells in a specific and saturable manner. Unlabeled TibA competed with biotin-labeled TibA, suggesting the presence of a specific TibA receptor in HCT8 cells. These results show that TibA acts as an adhesin. Polyclonal anti-TibA antiserum inhibited invasion of ETEC strain H10407 and of recombinant E. coli bearing tib locus clones, suggesting that TibA also acts as an invasin. The ability of TibA to direct epithelial cell adhesion suggests a role for this protein in ETEC pathogenesis. PMID:11119488

  14. Enterotoxigenic Escherichia coli TibA glycoprotein adheres to human intestine epithelial cells.

    PubMed

    Lindenthal, C; Elsinghorst, E A

    2001-01-01

    Enterotoxigenic Escherichia coli (ETEC) is capable of invading epithelial cell lines derived from the human ileum and colon. Two separate invasion loci (tia and tib) that direct noninvasive E. coli strains to adhere to and invade cultured human intestine epithelial cells have previously been isolated from the classical ETEC strain H10407. The tib locus directs the synthesis of TibA, a 104-kDa outer membrane glycoprotein. Synthesis of TibA is directly correlated with the adherence and invasion phenotypes of the tib locus, suggesting that this protein is an adhesin and invasin. Here we report the purification of TibA and characterization of its biological activity. TibA was purified by continuous-elution preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purified TibA was biotin labeled and then shown to bind to HCT8 human ileocecal epithelial cells in a specific and saturable manner. Unlabeled TibA competed with biotin-labeled TibA, suggesting the presence of a specific TibA receptor in HCT8 cells. These results show that TibA acts as an adhesin. Polyclonal anti-TibA antiserum inhibited invasion of ETEC strain H10407 and of recombinant E. coli bearing tib locus clones, suggesting that TibA also acts as an invasin. The ability of TibA to direct epithelial cell adhesion suggests a role for this protein in ETEC pathogenesis. PMID:11119488

  15. Towards tailored and targeted adherence assessment to optimise asthma management.

    PubMed

    van Boven, Job F M; Trappenburg, Jaap C A; van der Molen, Thys; Chavannes, Niels H

    2015-01-01

    In this paper, we aim to emphasise the need for a more comprehensive and tailored approach to manage the broad nature of non-adherence, to personalise current asthma management. Although currently several methods are available to measure the extent of asthma patients' adherence, the vast majority do not incorporate confirmation of the actual inhalation, dose and inhalation technique. Moreover, most current measures lack detailed information on the individual consequences of non-adherence and on when and how to take action if non-adherence is identified. Notably, one has to realise there are several forms of non-adherence (erratic non-adherence, intelligent non-adherence and unwitting non-adherence), each requiring a different approach. To improve asthma management, more accurate methods are needed that integrate measures of non-adherence, asthma disease control and patient preferences. Integrating information from the latest inhaler devices and patient-reported outcomes using mobile monitoring- and feedback systems ('mHealth') is considered a promising strategy, but requires careful implementation. Key issues to be considered before large-scale implementation include patient preferences, large heterogeneity in patient and disease characteristics, economic consequences, and long-term persistence with new digital technologies.

  16. HIV Treatment Adherence, Drug Resistance, Virologic Failure: Evolving Concepts

    PubMed Central

    Nachega, Jean B.; Marconi, Vincent C.; van Zyl, Gert U.; Gardner, Edward M.; Preiser, Wolfgang; Hong, Steven Y.; Mills, Edward J.; Gross, Robert

    2016-01-01

    Poor adherence to combined antiretroviral therapy (cART) has been shown to be a major determinant of virologic failure, emergence of drug resistant virus, disease progression, hospitalizations, mortality, and health care costs. While high adherence levels can be achieved in both resource-rich and resource-limited settings following initiation of cART, long-term adherence remains a challenge regardless of available resources. Barriers to optimal adherence may originate from individual (biological, socio-cultural, behavioral), pharmacological, and societal factors. Although patients and providers should continuously strive for maximum adherence to cART, there is accumulating evidence that each class of antiretroviral therapy has specific adherence-drug resistance relationship characteristics allowing certain regimens more flexibility than others. There is not a universally accepted measure for cART adherence, since each method has distinct advantages and disadvantages including cost, complexity, accuracy, precision, intrusiveness and bias. Development of a real-time cART adherence monitoring tool will enable the development of novel, pre-emptive adherence-improving strategies. The application of these strategies may ultimately prove to be the most cost-effective method to reduce morbidity and mortality for the individual and decrease the likelihood of HIV transmission and emergence of resistance in the community. PMID:21406048

  17. Towards tailored and targeted adherence assessment to optimise asthma management

    PubMed Central

    van Boven, Job FM; Trappenburg, Jaap CA; van der Molen, Thys; Chavannes, Niels H

    2015-01-01

    In this paper, we aim to emphasise the need for a more comprehensive and tailored approach to manage the broad nature of non-adherence, to personalise current asthma management. Although currently several methods are available to measure the extent of asthma patients’ adherence, the vast majority do not incorporate confirmation of the actual inhalation, dose and inhalation technique. Moreover, most current measures lack detailed information on the individual consequences of non-adherence and on when and how to take action if non-adherence is identified. Notably, one has to realise there are several forms of non-adherence (erratic non-adherence, intelligent non-adherence and unwitting non-adherence), each requiring a different approach. To improve asthma management, more accurate methods are needed that integrate measures of non-adherence, asthma disease control and patient preferences. Integrating information from the latest inhaler devices and patient-reported outcomes using mobile monitoring- and feedback systems (‘mHealth’) is considered a promising strategy, but requires careful implementation. Key issues to be considered before large-scale implementation include patient preferences, large heterogeneity in patient and disease characteristics, economic consequences, and long-term persistence with new digital technologies. PMID:26181850

  18. Heart failure patient adherence: epidemiology, cause, and treatment.

    PubMed

    Corotto, Paul S; McCarey, Melissa M; Adams, Suzanne; Khazanie, Prateeti; Whellan, David J

    2013-01-01

    Poor adherence to therapeutic regimens is a significant impediment to improving clinical outcomes in the HF population. Typical rates of adherence to prescribed medications, low-sodium diets, and aerobic exercise programs remain lower than that needed to decrease morbidity and mortality associated with HF. Factors contributing to poor adherence include multiple comorbidities, clinical depression, and decreased cognitive functioning. HF education and programs to enhance self-management skills have improved patient quality of life but have yet to decrease mortality or rehospitalization rates significantly. Telemonitoring to improve adherence behaviors and self-management interventions within broader HF management programs have demonstrated significant clinical improvements in this population.

  19. Simultaneous measurement of the viability, aggregation, and live and dead adherence of Streptococcus crista, Streptococcus mutans and Actinobacillus actinomycetemcomitans in human saliva in relation to indices of caries, dental plaque and periodontal disease.

    PubMed

    Rudney, J D; Staikov, R K

    2002-05-01

    Salivary proteins have multiple functions and many share similar functions, which may be why it has been difficult to relate variations in their concentrations to oral health and ecology. An alternative is to focus on variations in the major functions of saliva. An hydroxyapatite-coated microplate model has been developed that simultaneously measures saliva-promoted bacterial viability, bacterial aggregation, and live and dead bacterial adherence, while simulating oral temperature and shearing forces from swallowing. That model was applied to resting whole and stimulated parotid saliva from 149 individuals, using representative strains of Streptococcus crista, S. mutans, and Actinobacillus actinomycetemcomitans. Two major factors were defined by multivariate analysis (this was successful only for whole-saliva). One factor was correlated with aggregation, live adherence and dead adherence for all three strains; the other was correlated with total viability of all three strains. Participants were grouped <25th percentile and >75th percentile for each factor. Those groups were compared for clinical indices of oral health. Caries scores were significantly lower in those with high scores for aggregation-adherence, regardless of whether total viability scores were low or high. Live bacteria always predominated on surfaces when live and dead adherence scores were expressed as ratios. However, participants with high scores for aggregation-adherence showed significantly more dead adherent bacteria than those with low scores (these ratios were uncorrelated with total viability). This finding may indicate that extreme differences in the ability to kill bacteria on surfaces can influence caries risk.

  20. Research on the demodulation techniques of long-period fiber gratings strain sensing with low cost

    NASA Astrophysics Data System (ADS)

    Wang, Qingwei; Liu, Yueming; Tian, Weijian; Feng, Guilan

    2012-10-01

    The working principle of LPFG(Long-Period Fiber Grating) is based on coupling effect between propagating core-mode and co-propagating cladding-modes. The effective refractive index of cladding-modes could be obviously influenced by the environmental changes resulting in LPFG more sensitive than FBG (Fiber Bragg Grating) in sensing areas, such as temperature, strain, concentration, bending and etc. LPFG should have more potential in the field of sensors compared with FBG. One of the challenges in using LPFG for environmental sensing is how to interrogate the signal from the LPFG transmission spectrum, due to the large spectral range of the resonant dip. Nowadays the application of LPFG is normally limited in signal interrogation of FBG as optical edge filter. The signal interrogation of LPFG itself needs further research. Presently research on signal interrogation of fiber grating focuses on wavelength interrogation. The aim of wavelength interrogation is to get the wavelength shift caused by environmental change. To solve these problems, a kind of strain sensing interrogation technique for LPFG with low-cost based on tunable FBGs has been developed. Comparing with the method using Fabry-Perot cavity, tunable FBGs can lower the cost with the guarantee of sensing precision. The cost is further lowered without using expensive optical instruments such as optical switch. The problem of temperature cross-sensitivity was solved by using reference gratings. An experiment was performed to demonstrate the interrogation system. And in the experiment, the sensing signal of LPFG applied 0-1300μɛ was successfully interrogated. The results of the interrogation system and OSA are similar.

  1. Both enzymatic and non-enzymatic properties of heat-labile enterotoxin are responsible for LT-enhanced adherence of enterotoxigenic Escherichia coli to porcine IPEC-J2 cells.

    PubMed

    Fekete, Peter Z; Mateo, Kristina S; Zhang, Weiping; Moxley, Rodney A; Kaushik, Radhey S; Francis, David H

    2013-06-28

    Previous studies in piglets indicate that heat labile enterotoxin (LT) expression enhances intestinal colonization by K88 adhesin-producing enterotoxigenic Escherichia coli (ETEC) as wild-type ETEC adhered to intestinal epithelium in substantially greater numbers than did non-toxigenic constructs. Enzymatic activity of the toxin was also shown to contribute to the adhesion of ETEC and non-ETEC bacteria to epithelial cells in culture. To further characterize the contribution of LT to host cell adhesion, a nontoxigenic, K88-producing E. coli was transformed with either the gene encoding for LT holotoxin, a catalytically-attenuated form of the toxin [LT(R192G)], or LTB subunits, and resultant changes in bacterial adherence to IPEC-J2 porcine intestinal epithelial cells were measured. Strains expressing LT holotoxin or mutants were able to adhere in significantly higher numbers to IPEC-J2 cells than was an isogenic, toxin-negative construct. LT+ strains were also able to significantly block binding of a wild-type LT+ ETEC strain to IPEC-J2 cells. Adherence of isogenic strains to IPEC-J2 cells was unaltered by cycloheximide treatment, suggesting that LT enhances ETEC adherence to IPEC-J2 cells independent of host cell protein synthesis. However, pretreating IPEC-J2 cells with LT promoted adherence of negatively charged latex beads (a surrogate for bacteria which carry a negative change), which adherence was inhibited by cycloheximide, suggesting LT may induce a change in epithelial cell membrane potential. Overall, these data suggest that LT may enhance ETEC adherence by promoting an association between LTB and epithelial cells, and by altering the surface charge of the host plasma membrane to promote non-specific adherence.

  2. Both enzymatic and non-enzymatic properties of heat-labile enterotoxin are responsible for LT-enhanced adherence of enterotoxigenic Escherichia coli to porcine IPEC-J2 cells.

    PubMed

    Fekete, Peter Z; Mateo, Kristina S; Zhang, Weiping; Moxley, Rodney A; Kaushik, Radhey S; Francis, David H

    2013-06-28

    Previous studies in piglets indicate that heat labile enterotoxin (LT) expression enhances intestinal colonization by K88 adhesin-producing enterotoxigenic Escherichia coli (ETEC) as wild-type ETEC adhered to intestinal epithelium in substantially greater numbers than did non-toxigenic constructs. Enzymatic activity of the toxin was also shown to contribute to the adhesion of ETEC and non-ETEC bacteria to epithelial cells in culture. To further characterize the contribution of LT to host cell adhesion, a nontoxigenic, K88-producing E. coli was transformed with either the gene encoding for LT holotoxin, a catalytically-attenuated form of the toxin [LT(R192G)], or LTB subunits, and resultant changes in bacterial adherence to IPEC-J2 porcine intestinal epithelial cells were measured. Strains expressing LT holotoxin or mutants were able to adhere in significantly higher numbers to IPEC-J2 cells than was an isogenic, toxin-negative construct. LT+ strains were also able to significantly block binding of a wild-type LT+ ETEC strain to IPEC-J2 cells. Adherence of isogenic strains to IPEC-J2 cells was unaltered by cycloheximide treatment, suggesting that LT enhances ETEC adherence to IPEC-J2 cells independent of host cell protein synthesis. However, pretreating IPEC-J2 cells with LT promoted adherence of negatively charged latex beads (a surrogate for bacteria which carry a negative change), which adherence was inhibited by cycloheximide, suggesting LT may induce a change in epithelial cell membrane potential. Overall, these data suggest that LT may enhance ETEC adherence by promoting an association between LTB and epithelial cells, and by altering the surface charge of the host plasma membrane to promote non-specific adherence. PMID:23517763

  3. Pulling long tubes from firmly adhered vesicles

    NASA Astrophysics Data System (ADS)

    Cuvelier, D.; Chiaruttini, N.; Bassereau, P.; Nassoy, P.

    2005-09-01

    We used optical tweezers to measure the force-extension curve for the elongation of nanotubes from adhered giant vesicles. We show that the force increases significantly with the length of the tube, which is drastically different from what is observed when the membrane tension is kept constant, e.g. by pipette aspiration. The absence of any force plateau is quantitatively analysed in the framework of the material model of membranes. In particular, we rationalize a counter-intuitive weaker force rise for long tubes and demonstrate that the measured force-length trace allows us to probe both the entropic regime (characterised by the bending rigidity) and the elastic regime (characterised by the area expansion modulus) of the lipid membrane.

  4. Quantification of dandruff adherence to hair.

    PubMed

    Piérard-Franchimont, C; Uhoda, E; Piérard, G E

    2005-10-01

    Dandruff adherence to hair shafts is a visible annoying phenomenon. The aspect can be recorded by different means including the ultraviolet light-enhanced visualization (ULEV) method and microscopy. We present another quantitative method. Hairs were clipped from the parietal scalp area of 25 volunteers complaining of dandruff. They were firmly applied onto cyanoacrylate-coated microscopic slides. Hairs were lifted up after 15-20 s leaving a cast in the adhesive coat. Dandruff were thus harvested from the hair shafts and remained attached to the cyanoacrylate coat. After staining, the material was submitted to image analysis to derive the dandruff density per unit length of hairs. In 11/25 subjects, a correlation was found between the width of the hair casts and the dandruff density. This method does not collect all dandruff along hair shafts, but data are likely representative of the whole corneocyte load. PMID:18492209

  5. What the newspapers say about medication adherence: a content analysis

    PubMed Central

    2013-01-01

    Background This study investigates the coverage of adherence to medicine by the UK and US newsprint media. Adherence to medicine is recognised as an important issue facing healthcare professionals and the newsprint media is a key source of health information, however, little is known about newspaper coverage of medication adherence. Methods A search of the newspaper database Nexis®UK from 2004–2011 was performed. Content analysis of newspaper articles which referenced medication adherence from the twelve highest circulating UK and US daily newspapers and their Sunday equivalents was carried out. A second researcher coded a 15% sample of newspaper articles to establish the inter-rater reliability of coding. Results Searches of newspaper coverage of medication adherence in the UK and US yielded 181 relevant articles for each country. There was a large increase in the number of scientific articles on medication adherence in PubMed® over the study period, however, this was not reflected in the frequency of newspaper articles published on medication adherence. UK newspaper articles were significantly more likely to report the benefits of adherence (p = 0.005), whereas US newspaper articles were significantly more likely to report adherence issues in the elderly population (p = 0.004) and adherence associated with diseases of the central nervous system (p = 0.046). The most commonly reported barriers to adherence were patient factors e.g. poor memory, beliefs and age, whereas, the most commonly reported facilitators to adherence were medication factors including simplified regimens, shorter treatment duration and combination tablets. HIV/AIDS was the single most frequently cited disease (reported in 20% of newspaper articles). Poor quality reporting of medication adherence was identified in 62% of newspaper articles. Conclusion Adherence is not well covered in the newspaper media despite a significant presence in the medical literature. The mass media have the

  6. Thin film strain gage development program

    NASA Technical Reports Server (NTRS)

    Grant, H. P.; Przybyszewski, J. S.; Anderson, W. L.; Claing, R. G.

    1983-01-01

    Sputtered thin-film dynamic strain gages of 2 millimeter (0.08 in) gage length and 10 micrometer (0.0004 in) thickness were fabricated on turbojet engine blades and tested in a simulated compressor environment. Four designs were developed, two for service to 600 K (600 F) and two for service to 900 K (1200 F). The program included a detailed study of guidelines for formulating strain-gage alloys to achieve superior dynamic and static gage performance. The tests included gage factor, fatigue, temperature cycling, spin to 100,000 G, and erosion. Since the installations are 30 times thinner than conventional wire strain gage installations, and any alteration of the aerodynamic, thermal, or structural performance of the blade is correspondingly reduced, dynamic strain measurement accuracy higher than that attained with conventional gages is expected. The low profile and good adherence of the thin film elements is expected to result in improved durability over conventional gage elements in engine tests.

  7. Subinhibitory concentrations of triclosan promote Streptococcus mutans biofilm formation and adherence to oral epithelial cells.

    PubMed

    Bedran, Telma Blanca Lombardo; Grignon, Louis; Spolidorio, Denise Palomari; Grenier, Daniel

    2014-01-01

    Triclosan is a general membrane-active agent with a broad-spectrum antimicrobial activity that is commonly used in oral care products. In this study, we investigated the effect of sub-minimum inhibitory concentrations (MICs) of triclosan on the capacity of the cariogenic bacterium Streptococcus mutans to form biofilm and adhere to oral epithelial cells. As quantified by crystal violet staining, biofilm formation by two reference strains of S. mutans was dose-dependently promoted, in the range of 2.2- to 6.2-fold, by 1/2 and 1/4 MIC of triclosan. Observations by scanning electron microscopy revealed the presence of a dense biofilm attached to the polystyrene surface. Growth of S. mutans in the presence of triclosan at sub-MICs also increased its capacity to adhere to a monolayer of gingival epithelial cells. The expression of several genes involved in adherence and biofilm formation in S. mutans was investigated by quantitative RT-PCR. It was found that sub-MICs of triclosan significantly increased the expression of comD, gtfC, and luxS, and to a lesser extent of gtfB and atlA genes. These findings stress the importance of maintaining effective bactericidal concentrations of therapeutic triclosan since sub-MICs may promote colonization of the oral cavity by S. mutans.

  8. In vitro adhesiveness and biotype of Gardnerella vaginalis strains in relation to the occurrence of clue cells in vaginal discharges.

    PubMed Central

    Scott, T G; Smyth, C J; Keane, C T

    1987-01-01

    Haemagglutination and tissue culture adherence tests using a McCoy cell line were used to examine the adherence characteristics of 105 strains of Gardnerella vaginalis. Each strain represented one isolate per patient. For each patient, a direct smear of vaginal discharge was examined for clue cells. The relation between in vitro adherence and the presence of clue cells was examined. There seemed to be no appreciable relation between the presence of clue cells in smears and the haemagglutinating activity of strains. In contrast, adherence as judged by the McCoy tissue culture system showed a significant relation to the presence of clue cells (p less than 0.001). Though both adhesive characteristics were not inhibited by mannose, the mechanism of haemagglutination of human red cells appeared to differ from that of adherence of tissue culture cells. The findings imply that the clue cell phenomenon is due to attachment of adherent strains of G vaginalis to epithelial cells. Adherent strains of G vaginalis may play a part in the pathogenesis of bacterial vaginosis. Images PMID:3493202

  9. Improved in vitro assay for determining the mucin adherence of bacteria sensitive to Triton X-100 treatment.

    PubMed

    Tsilia, Varvara; Van den Abbeele, Pieter; Van de Wiele, Tom

    2015-09-01

    Mucin-associated microbiota are in relatively close contact with the intestinal epithelium and may thus have a more pronounced effect on host health. We have previously developed a simple mucin agar assay to simulate initial mucus colonization by intestinal microbial communities. Adherence of microbiota was estimated using flow cytometry after detachment with Triton X-100. In this study, the effect of this detergent on the cultivability of both virulent and commensal strains was investigated. Mucin attachment of selected strains was evaluated using the mucin adhesion assay. Bacteria were dislodged from the mucin surface by incubation with Triton or from the whole mucin agar layer using a stomacher. Mechanical extraction resulted in 1.24 ± 0.42, 2.69 ± 0.44, and 1.56 ± 0.85 log CFU/mL higher plate counts of Lactobacillus rhamnosus, Bacillus cereus, and Escherichia coli strains, respectively, than the chemical method. The sensitivity of bacteria to Triton varied among microbial species and strains. Among others, Triton inhibited the growth of Salmonella enterica LMG 10396 and Pseudomonas aeruginosa LMG 8029 on laboratory media, although these bacteria maintained their viability during this treatment. Only Gram-positive strains, Enterococcus hirae LMG 6399 and L. rhamnosus GG, were not affected by this detergent. Therefore, the mechanical method is recommended for the extraction of mucin-adhered bacteria that are sensitive to Triton, especially when followed by traditional cultivation techniques. However, this approach can also be recommended for strains that are not affected by this detergent, because it resulted in higher recovery of adhered L. rhamnosus GG compared to the chemical extraction.

  10. Milk digesta and milk protein fractions influence the adherence of Lactobacillus gasseri R and Lactobacillus casei FMP to human cultured cells.

    PubMed

    Volstatova, Tereza; Havlik, Jaroslav; Potuckova, Miroslava; Geigerova, Martina

    2016-08-10

    Adhesion to the intestinal epithelium is considered an important feature of probiotic bacteria, which may increase their persistence in the intestine, allowing them to exert their beneficial health effect or promote the colonisation process. However, this feature might be largely dependent on the host specificity or diet. In the present study, we investigated the effect of selected milks and milk protein fractions on the ability of selected lactobacilli to adhere to the cells of an intestinal model based on co-culture Caco-2/HT29-MTX cell lines. Most milk digesta did not significantly affect bacterial adhesion except for UHT-treated milk and sheep milk. The presence of UHT-treated milk digesta reduced the adhesion of Lactobacillus gasseri R by 61% but not that of Lactobacillus casei FMP. However, sheep milk significantly increased the adherence of L. casei FMP (P < 0.05) but not of L. gasseri R. Among the protein fractions, rennet casein (RCN) and bovine serum albumin (BSA) showed reproducible patterns and strain-specific effects on bacterial adherence. While RCN reduced the adherence of L. gasseri R to <50% compared to the control, it did not have a significant effect on L. casei FMP. In contrast, BSA reduced L. casei FMP adherence to a higher extent than that of L. gasseri R. Whey protein (WH) tended to increase the adherence of both strains by 130%-180%. Recently, interactions between the host diet and its microbiota have attracted considerable interest. Our results may explain one of the aspects of the role of milk in the development of microbiota or support of probiotic supplements. Based on our data, we conclude that the persistence of probiotic strains supplemented as part of dairy food or constitutional microbiota in the gut might be affected negatively or positively by the food matrix through complex strain or concentration dependent effects. PMID:27435508

  11. Milk digesta and milk protein fractions influence the adherence of Lactobacillus gasseri R and Lactobacillus casei FMP to human cultured cells.

    PubMed

    Volstatova, Tereza; Havlik, Jaroslav; Potuckova, Miroslava; Geigerova, Martina

    2016-08-10

    Adhesion to the intestinal epithelium is considered an important feature of probiotic bacteria, which may increase their persistence in the intestine, allowing them to exert their beneficial health effect or promote the colonisation process. However, this feature might be largely dependent on the host specificity or diet. In the present study, we investigated the effect of selected milks and milk protein fractions on the ability of selected lactobacilli to adhere to the cells of an intestinal model based on co-culture Caco-2/HT29-MTX cell lines. Most milk digesta did not significantly affect bacterial adhesion except for UHT-treated milk and sheep milk. The presence of UHT-treated milk digesta reduced the adhesion of Lactobacillus gasseri R by 61% but not that of Lactobacillus casei FMP. However, sheep milk significantly increased the adherence of L. casei FMP (P < 0.05) but not of L. gasseri R. Among the protein fractions, rennet casein (RCN) and bovine serum albumin (BSA) showed reproducible patterns and strain-specific effects on bacterial adherence. While RCN reduced the adherence of L. gasseri R to <50% compared to the control, it did not have a significant effect on L. casei FMP. In contrast, BSA reduced L. casei FMP adherence to a higher extent than that of L. gasseri R. Whey protein (WH) tended to increase the adherence of both strains by 130%-180%. Recently, interactions between the host diet and its microbiota have attracted considerable interest. Our results may explain one of the aspects of the role of milk in the development of microbiota or support of probiotic supplements. Based on our data, we conclude that the persistence of probiotic strains supplemented as part of dairy food or constitutional microbiota in the gut might be affected negatively or positively by the food matrix through complex strain or concentration dependent effects.

  12. Adherence to a Strength Training Intervention in Adult Women

    PubMed Central

    Arikawa, Andrea Y.; O’Dougherty, Maureen; Schmitz, Kathryn

    2010-01-01

    Background The factors influencing exercise adherence are not well characterized in women in their premenopausal years. Methods The purpose of this report is to provide an analysis of demographic factors contributing to women’s adherence to a two-year twice-weekly weight training intervention. Overweight and obese premenopausal women were randomized to a control or intervention group. Results During the supervised period of the intervention (months 1–4), adherence was significantly lower among those with a higher level of education and among unmarried women with children aged six to twelve compared to married women without children (F = 4.83, p = 0.004). Overall adherence during the supervised and unsupervised periods was 95.4% and 64.5%, respectively (unadjusted mean). During year 1, white women were significantly more adherent to the intervention (70.3%) than women of color (48.6%). Non-married women with children 13 years or older were significantly less adherent than married women with children 5 years or younger (36.3% vs 75.4%, respectively, p < 0.007). Overall adherence was 51.4% in year 2. Conclusions Interventions and public health recommendations need to further consider how to engage communities to provide effective support for long-term adherence to fitness center based exercise of all women, regardless of demographics. PMID:21297191

  13. Improving Adherence to Hand Hygiene among Health Care Workers

    ERIC Educational Resources Information Center

    Maskerine, Courtney; Loeb, Mark

    2006-01-01

    Increased adherence to hand hygiene is widely acknowledged to be the most important way of reducing infections in health care facilities. Despite evidence of benefit, adherence to hand hygiene among health care professionals remains low. Several behavioral and organizational theories have been proposed to explain this. As a whole, the success of…

  14. 29 CFR 1608.8 - Adherence to court order.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... APPROPRIATE UNDER TITLE VII OF THE CIVIL RIGHTS ACT OF 1964, AS AMENDED § 1608.8 Adherence to court order. Parties are entitled to rely on orders of courts of competent jurisdiction. If adherence to an Order of a United States District Court or other court of competent jurisdiction, whether entered by consent...

  15. 29 CFR 1608.8 - Adherence to court order.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... APPROPRIATE UNDER TITLE VII OF THE CIVIL RIGHTS ACT OF 1964, AS AMENDED § 1608.8 Adherence to court order. Parties are entitled to rely on orders of courts of competent jurisdiction. If adherence to an Order of a United States District Court or other court of competent jurisdiction, whether entered by consent...

  16. 29 CFR 1608.8 - Adherence to court order.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... APPROPRIATE UNDER TITLE VII OF THE CIVIL RIGHTS ACT OF 1964, AS AMENDED § 1608.8 Adherence to court order. Parties are entitled to rely on orders of courts of competent jurisdiction. If adherence to an Order of a United States District Court or other court of competent jurisdiction, whether entered by consent...

  17. 29 CFR 1608.8 - Adherence to court order.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... APPROPRIATE UNDER TITLE VII OF THE CIVIL RIGHTS ACT OF 1964, AS AMENDED § 1608.8 Adherence to court order. Parties are entitled to rely on orders of courts of competent jurisdiction. If adherence to an Order of a United States District Court or other court of competent jurisdiction, whether entered by consent...

  18. 29 CFR 1608.8 - Adherence to court order.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... APPROPRIATE UNDER TITLE VII OF THE CIVIL RIGHTS ACT OF 1964, AS AMENDED § 1608.8 Adherence to court order. Parties are entitled to rely on orders of courts of competent jurisdiction. If adherence to an Order of a United States District Court or other court of competent jurisdiction, whether entered by consent...

  19. Methodologies for medication adherence evaluation: Focus on psoriasis topical treatment.

    PubMed

    Teixeira, Ana; Teixeira, Maribel; Almeida, Vera; Torres, Tiago; Sousa Lobo, José Manuel; Almeida, Isabel Filipa

    2016-05-01

    Adherence to topical treatment has been less studied in comparison with systemic therapeutic regimens and is poorly understood. High-quality research on this area is essential to outline a strategy to increase medication adherence and clinical outcomes. For a more comprehensive understanding of this issue, a systematic review of the methodologies for topical treatment adherence evaluation in psoriasis was undertaken. Twenty one studies were selected from the literature which used six different adherence methodologies. Merely three studies used multiple adherence measurement methods. The most used method was questionnaire (44%) which was also associated with higher variability of the adherence results. One possible explanation is the lack of a validated questionnaire designed specifically for the evaluation of adherence to topical treatment. Only one method (medication weight) takes into consideration the applied dose. However, the estimation of the expected weight is complex, which renders this method, as used presently, less effective. The use of a dosing device could improve its accuracy and be helpful to clearly instruct the patients about the correct dose. As there is no single method that allows an accurate and complete assessment of adherence it is recommended to use a combination of methods, including self-report and medicines' weight measurements.

  20. Adherence to Pharmacological Treatment for Juvenile Bipolar Disorder

    ERIC Educational Resources Information Center

    Drotar, Dennis; Greenley, Rachel Neff; Demeter, Christine A.; McNamara, Nora K.; Stansbrey, Robert J.; Calabrese, Joseph R.; Stange, Jonathan; Vijay, Priya; Findling, Robert L.

    2007-01-01

    Objective: The objective of this study was to describe the prevalence and correlates of adherence to divalproex sodium (DVPX) and lithium carbonate (Li) combination treatment during the initial stabilization treatment phase. Method: Adherence to Li/DVPX combination therapy was measured by the presence or absence of minimum serum concentrations of…

  1. Medication Adherence in a Comparative Effectiveness Trial for Bipolar Disorder

    PubMed Central

    Sylvia, Louisa G.; Reilly-Harrington, Noreen A.; Leon, Andrew C.; Kansky, Christine I.; Calabrese, Joseph R.; Bowden, Charles L.; Ketter, Terence A.; Friedman, Edward S.; Iosifescu, Dan V.; Thase, Michael E.; Ostacher, Michael J.; Keyes, Michelle; Rabideau, Dustin; Nierenberg, Andrew A.

    2013-01-01

    Objective Psychopharmacology remains the foundation of treatment for bipolar disorder, but medication adherence in this population is low (Range = 20% to 64%). We examined medication adherence in a multi-site, comparative effectiveness study of lithium. Method The Lithium Moderate Dose Use Study (LiTMUS) was a six-month, six-site, randomized effectiveness trial of adjunctive moderate dose lithium therapy compared to optimized treatment in adult outpatients with bipolar I or II disorder (N=283). Medication adherence was measured at each study visit with the Tablet Routine Questionnaire. Results We found that 4.50% of participants reported missing at least 30% of their medications in the past week at baseline and non-adherence remained low throughout the trial (< 7%). Poor medication adherence was associated with more manic symptoms and side effects as well as lower lithium serum levels at mid- and post-treatment, but not with poor quality of life, overall severity of illness, or depressive symptoms. Conclusion Participants in LiTMUS were highly adherent with taking their medications. The lack of association with possible predictors of adherence, such as depression and quality of life, could be explained by the limited variance or other factors as well as by not using an objective measure of adherence. PMID:24117232

  2. 14 CFR 1260.72 - Adherence to original budget estimates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... COOPERATIVE AGREEMENTS General Post-Award Requirements § 1260.72 Adherence to original budget estimates. (a) Although NASA assumes no responsibility for budget overruns, the recipient may spend grant funds without... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Adherence to original budget...

  3. 14 CFR 1260.72 - Adherence to original budget estimates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... COOPERATIVE AGREEMENTS General Post-Award Requirements § 1260.72 Adherence to original budget estimates. (a) Although NASA assumes no responsibility for budget overruns, the recipient may spend grant funds without... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Adherence to original budget estimates....

  4. 14 CFR 1260.72 - Adherence to original budget estimates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... COOPERATIVE AGREEMENTS General Post-Award Requirements § 1260.72 Adherence to original budget estimates. (a) Although NASA assumes no responsibility for budget overruns, the recipient may spend grant funds without... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Adherence to original budget...

  5. Method for preventing micromechanical structures from adhering to another object

    DOEpatents

    Smith, J.H.; Ricco, A.J.

    1998-06-16

    A method for preventing micromechanical structures from adhering to another object includes the step of immersing a micromechanical structure and its associated substrate in a chemical species that does not stick to itself. The method can be employed during the manufacture of micromechanical structures to prevent micromechanical parts from sticking or adhering to one another and their associated substrate surface. 3 figs.

  6. Enhancing Commitment Improves Adherence to a Medical Regimen.

    ERIC Educational Resources Information Center

    Putnam, Dana E.; And Others

    1994-01-01

    Evaluated commitment-based intervention for improvement of adherence to 10-day antibiotic regimen. Subjects were 60 college students. Experimental subjects made verbal and written commitments for adherence and completed tasks designed to increase their investment in medication regimen. Controls performed similarly structured tasks unrelated to…

  7. Clinical Supervision in Treatment Transport: Effects on Adherence and Outcomes

    ERIC Educational Resources Information Center

    Schoenwald, Sonja K.; Sheidow, Ashli J.; Chapman, Jason E.

    2009-01-01

    This nonexperimental study used mixed-effects regression models to examine relations among supervisor adherence to a clinical supervision protocol, therapist adherence, and changes in the behavior and functioning of youths with serious antisocial behavior treated with an empirically supported treatment (i.e., multisystemic therapy [MST]) 1 year…

  8. Thirty-Three Years of Aerobic Exercise Adherence.

    ERIC Educational Resources Information Center

    Kasch, Frederick W.

    2001-01-01

    Followed 15 middle-aged men for 25-33 years while they participated in an aerobic exercise program. Adherence in the sample was 100 percent. Possible explanations for the adherence include program leadership, peer support, written evaluations and progress reports, emphasis on health, early and continued interest in sport and exercise, recognition…

  9. Medication Adherence in Older Adults: A Qualitative Study

    ERIC Educational Resources Information Center

    Holt, Elizabeth W.; Rung, Ariane L.; Leon, Kyla A.; Firestein, Catherine; Krousel-Wood, Marie

    2014-01-01

    To effectively address medication adherence and improve cardiovascular health among older adults, a deeper understanding is needed of the barriers that this age group faces and of approaches that would be most effective and feasible for improving adherence. We conducted a focus group study (n = 25) in a diverse population of older adults with…

  10. Cognitive-Behavioral Therapy for HIV Medication Adherence and Depression

    ERIC Educational Resources Information Center

    Safren, Steven A.; Hendriksen, Ellen S.; Mayer, Kenneth H.; Mimiaga, Matthew J.; Pickard, Robert; Otto, Michael W.

    2004-01-01

    For patients with HIV, depression is a common, distressing condition that can interfere with a critical self-care behavior--adherence to antiretroviral therapy. The present study describes a cognitive-behavioral treatment designed to integrate cognitive-behavioral therapy for depression with our previously tested approach to improving adherence to…

  11. Method for preventing micromechanical structures from adhering to another object

    DOEpatents

    Smith, James H.; Ricco, Antonio J.

    1998-01-01

    A method for preventing micromechanical structures from adhering to another object includes the step of immersing a micromechanical structure and its associated substrate in a chemical species that does not stick to itself. The method can be employed during the manufacture of micromechanical structures to prevent micromechanical parts from sticking or adhering to one another and their associated substrate surface.

  12. Teaching Medication Adherence in US Colleges and Schools of Pharmacy

    PubMed Central

    MacLean, Linda Garrelts; Hess, Karl; Farmer, Kevin C.; Yurkon, Afton M.; Ha, Carolyn C.; Schwartzman, Emmanuelle; Law, Anandi V.; Milani, Paul A.; Trotta, Katie; Labella, Sara R.; Designor, Rebecca J.

    2012-01-01

    Objective. To determine and describe the nature and extent of medication adherence education in US colleges and schools of pharmacy. Methods. A mixed-methods research study was conducted that included a national survey of pharmacy faculty members, a national survey of pharmacy students, and phone interviews of 3 faculty members and 6 preceptors. Results. The majority of faculty members and students agreed that background concepts in medication adherence are well covered in pharmacy curricula. Approximately 40% to 65% of the students sampled were not familiar with several adherence interventions. The 6 preceptors who were interviewed felt they were not well-informed on adherence interventions, unclear on what students knew about adherence, and challenged to provide adherence-related activities for students during practice experiences because of practice time constraints. Conclusions. Intermediate and advanced concepts in medication adherence, such as conducting interventions, are not adequately covered in pharmacy curriculums; therefore stakeholders in pharmacy education must develop national standards and tools to ensure consistent and adequate medication adherence education. PMID:22761520

  13. Treatment Adherence among Latina Female Adolescent Suicide Attempters.

    ERIC Educational Resources Information Center

    Rotheram-Borus, Mary Jane; Piacentini, John; Van Rossem, Ronan; Graae, Flemming; Cantwell, Coleen; Castro-Blanco, David; Feldman, Julie

    1999-01-01

    Disenfranchised Latina adolescents (N=140) and their mothers presenting at a large urban emergency room after a suicide attempt by the adolescent were assessed to examine treatment adherence. Predictor variables for treatment adherence were established. Results are discussed in relation to treatment session attendance. Implications for the…

  14. Ultrastructural study of Helicobacter pylori adherence properties in gnotobiotic piglets.

    PubMed Central

    Rudmann, D G; Eaton, K A; Krakowka, S

    1992-01-01

    Ultrastructural examination of gastric mucosa from Helicobacter pylori-infected gnotobiotic piglets identified four general adherence patterns comparable to those observed in human patients. Intimate associations between the bacterial and mucosal cell membranes, including cuplike invaginations and adherence pedestals, were present and were accompanied by alterations to microvilli and cell membrane morphology. Images PMID:1563801

  15. Component Analysis of Adherence in a Family Intervention

    ERIC Educational Resources Information Center

    Hill, Laura G.; Owens, Robert W.

    2013-01-01

    Purpose: Most studies of adherence use a single global measure to examine the relation of adherence to outcomes. These studies inform us about effects of overall implementation but not about importance of specific program elements. Previous research on the Strengthening Families Program 10-14 has shown that outcomes were unrelated to global…

  16. Adherence, shared decision-making and patient autonomy.

    PubMed

    Sandman, Lars; Granger, Bradi B; Ekman, Inger; Munthe, Christian

    2012-05-01

    In recent years the formerly quite strong interest in patient compliance has been questioned for being too paternalistic and oriented towards overly narrow biomedical goals as the basis for treatment recommendations. In line with this there has been a shift towards using the notion of adherence to signal an increased weight for patients' preferences and autonomy in decision making around treatments. This 'adherence-paradigm' thus encompasses shared decision-making as an ideal and patient perspective and autonomy as guiding goals of care. What this implies in terms of the importance that we have reason to attach to (non-)adherence and how has, however, not been explained. In this article, we explore the relationship between different forms of shared decision-making, patient autonomy and adherence. Distinguishing between dynamically and statically framed adherence we show how the version of shared decision-making advocated will have consequences for whether one should be interested in a dynamically or statically framed adherence and in what way patient adherence should be assessed. In contrast to the former compliance paradigm (where non-compliance was necessarily seen as a problem), using observations about (non-)adherence to assess the success of health care decision making and professional-patient interaction turns out to be a much less straightforward matter.

  17. Genetic factors in exercise adoption, adherence and obesity.

    PubMed

    Herring, M P; Sailors, M H; Bray, M S

    2014-01-01

    Physical activity and exercise play critical roles in energy balance. While many interventions targeted at increasing physical activity have demonstrated efficacy in promoting weight loss or maintenance in the short term, long term adherence to such programmes is not frequently observed. Numerous factors have been examined for their ability to predict and/or influence physical activity and exercise adherence. Although physical activity has been demonstrated to have a strong genetic component in both animals and humans, few studies have examined the association between genetic variation and exercise adherence. In this review, we provide a detailed overview of the non-genetic and genetic predictors of physical activity and adherence to exercise. In addition, we report the results of analysis of 26 single nucleotide polymorphisms in six candidate genes examined for association to exercise adherence, duration, intensity and total exercise dose in young adults from the Training Interventions and Genetics of Exercise Response (TIGER) Study. Based on both animal and human research, neural signalling and pleasure/reward systems in the brain may drive in large part the propensity to be physically active and to adhere to an exercise programme. Adherence/compliance research in other fields may inform future investigation of the genetics of exercise adherence.

  18. 14 CFR 1260.72 - Adherence to original budget estimates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Adherence to original budget estimates. 1260.72 Section 1260.72 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Post-Award Requirements § 1260.72 Adherence to original budget estimates....

  19. The Influence of Goal Setting on Exercise Adherence.

    ERIC Educational Resources Information Center

    Cobb, Lawrence E.; Stone, William J.; Anonsen, Lori J.; Klein, Diane A.

    2000-01-01

    Assessed the influence of fitness- and health-related goal setting on exercise adherence. Students in a college fitness program participated in goal setting, reading, or control groups. No significant differences in exercise adherence were found. Students enrolled for letter grades had more fitness center visits and hours of activity than students…

  20. ENHANCE—(Electronic Hydroxyurea Adherence): A Protocol to Increase Hydroxyurea Adherence in Patients with Sickle Cell Disease

    PubMed Central

    Chisolm, Deena J; O’Brien, Sarah H

    2016-01-01

    Background Hydroxyurea (HU) is the only disease-modifying medication for patients with sickle cell disease (SCD). HU can reduce SCD-related complications but only 35% to 50% of pediatric patients adhere to HU at the rates achieved in clinical trials and this limits its clinical effectiveness. Mobile Directly Observed Therapy (Mobile DOT) is a pilot-tested, electronic, multidimensional, HU adherence intervention that targets many components of the Health Behavior Model. Objective The aim of this study is to evaluate the impact of Mobile DOT on HU adherence in children with SCD. The objective of our study is to inform the development of future adherence interventions and pediatric SCD protocols. Methods This is a single-arm crossover study of pediatric patients with SCD. Participants self-record videos of their daily HU administrations and receive text message alerts to take HU, feedback on their HU adherence, and incentives when they achieve adherence goals during the 6-month Mobile DOT phase. Participants’ HU adherence during the Mobile DOT phase is compared with their baseline HU adherence (6 months prior to study entry) and to their HU adherence 6 months after completing the Mobile DOT phase. The primary outcome of this study is HU adherence measured by medication possession ratio. Results The trial is ongoing. Preliminary review of participant satisfaction results suggest that most participants can complete Mobile DOT in less than 5 minutes per day and are satisfied with the intervention. Conclusions If effective, the Mobile DOT strategy will increase HU adherence and this could improve patients’ clinical outcomes and reduce costs of care. PMID:27697749