WorldWideScience

Sample records for bioluminescence tomography based

  1. Bioluminescence tomography based on the phase approximation model

    OpenAIRE

    Cong, W; Wang, G.

    2010-01-01

    A reconstruction method of bioluminescence sources is proposed based on a phase approximation model. Compared with the diffuse approximation, this phase approximation model more correctly predicts bioluminescence photon propagation in biological tissues, so that bioluminescence tomography can accurately locate and quantify the distribution of bioluminescence sources. The compressive sensing (CS) technique is applied to regularize the inverse source reconstruction to enhance numerical stabilit...

  2. A novel reconstruction algorithm for bioluminescent tomography based on Bayesian compressive sensing

    Science.gov (United States)

    Wang, Yaqi; Feng, Jinchao; Jia, Kebin; Sun, Zhonghua; Wei, Huijun

    2016-03-01

    Bioluminescence tomography (BLT) is becoming a promising tool because it can resolve the biodistribution of bioluminescent reporters associated with cellular and subcellular function through several millimeters with to centimeters of tissues in vivo. However, BLT reconstruction is an ill-posed problem. By incorporating sparse a priori information about bioluminescent source, enhanced image quality is obtained for sparsity based reconstruction algorithm. Therefore, sparsity based BLT reconstruction algorithm has a great potential. Here, we proposed a novel reconstruction method based on Bayesian compressive sensing and investigated its feasibility and effectiveness with a heterogeneous phantom. The results demonstrate the potential and merits of the proposed algorithm.

  3. A multithread based new sparse matrix method in bioluminescence tomography

    Science.gov (United States)

    Zhang, Bo; Tian, Jie; Liu, Dan; Sun, Li; Yang, Xin; Han, Dong

    2010-03-01

    Among many molecular imaging modalities, bioluminescence tomography (BLT) stands out as an effective approach for in vivo imaging because of its noninvasive molecular and cellular level detection ability, high sensitivity and low cost in comparison with other imaging technologies. However, there exists the case that large scale problem with large number of points and elements in the structure of mesh standing for the small animal or phantom. And the large scale problem's system matrix generated by the diffuse approximation (DA) model using finite element method (FEM) is large. So there wouldn't be enough random access memory (RAM) for the program and the related inverse problem couldn't be solved. Considering the sparse property of the BLT system matrix, we've developed a new sparse matrix (ZSM) to overcome the problem. And the related algorithms have all been speeded up by multi-thread technologies. Then the inverse problem is solved by Tikhonov regularization method in adaptive finite element (AFE) framework. Finally, the performance of this method is tested on a heterogeneous phantom and the boundary data is obtained through Monte Carlo simulation. During the process of solving the forward model, the ZSM can save more processing time and memory space than the usual way, such as those not using sparse matrix and those using Triples or Cross Linked sparse matrix. Numerical experiments have shown when more CPU cores are used, the processing speed is increased. By incorporating ZSM, BLT can be applied to large scale problems with large system matrix.

  4. Bioluminescence tomography with Gaussian prior

    OpenAIRE

    Gao, Hao; Zhao, Hongkai; Cong, Wenxiang; Wang, Ge

    2010-01-01

    Parameterizing the bioluminescent source globally in Gaussians provides several advantages over voxel representation in bioluminescence tomography. It is mathematically unique to recover Gaussians [Med. Phys. 31(8), 2289 (2004)] and practically sufficient to approximate various shapes by Gaussians in diffusive medium. The computational burden is significantly reduced since much fewer unknowns are required. Besides, there are physiological evidences that the source can be modeled by Gaussians....

  5. In vivo bioluminescence tomography based on multi-view projection and 3D surface reconstruction

    Science.gov (United States)

    Zhang, Shuang; Wang, Kun; Leng, Chengcai; Deng, Kexin; Hu, Yifang; Tian, Jie

    2015-03-01

    Bioluminescence tomography (BLT) is a powerful optical molecular imaging modality, which enables non-invasive realtime in vivo imaging as well as 3D quantitative analysis in preclinical studies. In order to solve the inverse problem and reconstruct inner light sources accurately, the prior structural information is commonly necessary and obtained from computed tomography or magnetic resonance imaging. This strategy requires expensive hybrid imaging system, complicated operation protocol and possible involvement of ionizing radiation. The overall robustness highly depends on the fusion accuracy between the optical and structural information. In this study we present a pure optical bioluminescence tomographic system (POBTS) and a novel BLT method based on multi-view projection acquisition and 3D surface reconstruction. The POBTS acquired a sparse set of white light surface images and bioluminescent images of a mouse. Then the white light images were applied to an approximate surface model to generate a high quality textured 3D surface reconstruction of the mouse. After that we integrated multi-view luminescent images based on the previous reconstruction, and applied an algorithm to calibrate and quantify the surface luminescent flux in 3D.Finally, the internal bioluminescence source reconstruction was achieved with this prior information. A BALB/C mouse with breast tumor of 4T1-fLuc cells mouse model were used to evaluate the performance of the new system and technique. Compared with the conventional hybrid optical-CT approach using the same inverse reconstruction method, the reconstruction accuracy of this technique was improved. The distance error between the actual and reconstructed internal source was decreased by 0.184 mm.

  6. Improved AFEM algorithm for bioluminescence tomography based on dual-mesh alternation strategy

    Institute of Scientific and Technical Information of China (English)

    Wei Li; Heng Zhao; Xiaochao Qu; Yanbin Hou; Xueli Chen; Duofang Chen; Xiaowei He; Qitan Zhang; Jimin Liang

    2012-01-01

    Adaptive finite element method (AFEM) is broadly adopted to recover the internal source in biological tissues.In this letter,a novel dual-mesh alternation strategy (dual-mesh AFEM) is developed for bioluminescence tomography.By comprehensively considering the error estimation of the finite element method solution on each mesh,two different adaptive strategies based on the error indicator of the reconstructed source and the photon flux density are used alternately in the process.Combined with the constantly adjusted permissible region in the adaptive process,the new algorithm can achieve a more accurate source location compared with the AFEM in the previous experiments.%Adaptive finite element method (AFEM) is broadly adopted to recover the internal source in biological tissues. In this letter, a novel dual-mesh alternation strategy (dual-mesh AFEM) is developed for biolumi-nescence tomography. By comprehensively considering the error estimation of the finite element method solution on each mesh, two different adaptive strategies based on the error indicator of the reconstructed source and the photon flux density are used alternately in the process. Combined with the constantly adjusted permissible region in the adaptive process, the new algorithm can achieve a more accurate source location compared with the AFEM in the previous experiments.

  7. A Table-Based Random Sampling Simulation for Bioluminescence Tomography

    Directory of Open Access Journals (Sweden)

    Xiaomeng Zhang

    2006-01-01

    Full Text Available As a popular simulation of photon propagation in turbid media, the main problem of Monte Carlo (MC method is its cumbersome computation. In this work a table-based random sampling simulation (TBRS is proposed. The key idea of TBRS is to simplify multisteps of scattering to a single-step process, through randomly table querying, thus greatly reducing the computing complexity of the conventional MC algorithm and expediting the computation. The TBRS simulation is a fast algorithm of the conventional MC simulation of photon propagation. It retained the merits of flexibility and accuracy of conventional MC method and adapted well to complex geometric media and various source shapes. Both MC simulations were conducted in a homogeneous medium in our work. Also, we present a reconstructing approach to estimate the position of the fluorescent source based on the trial-and-error theory as a validation of the TBRS algorithm. Good agreement is found between the conventional MC simulation and the TBRS simulation.

  8. Spectrally resolved bioluminescence tomography using the reciprocity approach

    OpenAIRE

    Dehghani, Hamid; Davis, Scott C.; Pogue, Brian W.

    2008-01-01

    Spectrally resolved bioluminescence optical tomography is an approach to recover images of, for example, Luciferase activity within a volume using multiwavelength emission data from internal bioluminescence sources. The underlying problem of uniqueness associated with nonspectrally resolved intensity-based bioluminescence tomography is demonstrated and it is shown that using a non-negative constraint inverse algorithm, an accurate solution for the source distribution can be calculated from th...

  9. A fast reconstruction algorithm for bioluminescence tomography based on smoothed l0 norm regularization

    Science.gov (United States)

    He, Xiaowei; Yu, Jingjing; Geng, Guohua; Guo, Hongbo

    2013-10-01

    As an important optical molecular imaging technique, bioluminescence tomography (BLT) offers an inexpensive and sensitive means for non-invasively imaging a variety of physiological and pathological activities at cellular and molecular levels in living small animals. The key problem of BLT is to recover the distribution of the internal bioluminescence sources from limited measurements on the surface. Considering the sparsity of the light source distribution, we directly formulate the inverse problem of BLT into an l0-norm minimization model and present a smoothed l0-norm (SL0) based reconstruction algorithm. By approximating the discontinuous l0 norm with a suitable continuous function, the SL0 norm method solves the problem of intractable computational load of the minimal l0 search as well as high sensitivity of l0-norm to noise. Numerical experiments on a mouse atlas demonstrate that the proposed SL0 norm based reconstruction method can obtain whole domain reconstruction without any a priori knowledge of the source permissible region, yielding almost the same reconstruction results to those of l1 norm methods.

  10. L1/2 regularization based numerical method for effective reconstruction of bioluminescence tomography

    Science.gov (United States)

    Chen, Xueli; Yang, Defu; Zhang, Qitan; Liang, Jimin

    2014-05-01

    Even though bioluminescence tomography (BLT) exhibits significant potential and wide applications in macroscopic imaging of small animals in vivo, the inverse reconstruction is still a tough problem that has plagued researchers in a related area. The ill-posedness of inverse reconstruction arises from insufficient measurements and modeling errors, so that the inverse reconstruction cannot be solved directly. In this study, an l1/2 regularization based numerical method was developed for effective reconstruction of BLT. In the method, the inverse reconstruction of BLT was constrained into an l1/2 regularization problem, and then the weighted interior-point algorithm (WIPA) was applied to solve the problem through transforming it into obtaining the solution of a series of l1 regularizers. The feasibility and effectiveness of the proposed method were demonstrated with numerical simulations on a digital mouse. Stability verification experiments further illustrated the robustness of the proposed method for different levels of Gaussian noise.

  11. L1/2 regularization based numerical method for effective reconstruction of bioluminescence tomography

    International Nuclear Information System (INIS)

    Even though bioluminescence tomography (BLT) exhibits significant potential and wide applications in macroscopic imaging of small animals in vivo, the inverse reconstruction is still a tough problem that has plagued researchers in a related area. The ill-posedness of inverse reconstruction arises from insufficient measurements and modeling errors, so that the inverse reconstruction cannot be solved directly. In this study, an l1/2 regularization based numerical method was developed for effective reconstruction of BLT. In the method, the inverse reconstruction of BLT was constrained into an l1/2 regularization problem, and then the weighted interior-point algorithm (WIPA) was applied to solve the problem through transforming it into obtaining the solution of a series of l1 regularizers. The feasibility and effectiveness of the proposed method were demonstrated with numerical simulations on a digital mouse. Stability verification experiments further illustrated the robustness of the proposed method for different levels of Gaussian noise

  12. Ultrasound Modulated Bioluminescence Tomography

    CERN Document Server

    Bal, Guillaume

    2013-01-01

    We propose a method to reconstruct the density of a luminescent source in a highly-scattering medium from ultrasound modulated optical measurements. Our approach is based on the solution to a hybrid inverse source problem for the diffusion equation.

  13. L{sub 1/2} regularization based numerical method for effective reconstruction of bioluminescence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xueli, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn; Yang, Defu; Zhang, Qitan; Liang, Jimin, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn [School of Life Science and Technology, Xidian University, Xi' an 710071 (China); Engineering Research Center of Molecular and Neuro Imaging, Ministry of Education (China)

    2014-05-14

    Even though bioluminescence tomography (BLT) exhibits significant potential and wide applications in macroscopic imaging of small animals in vivo, the inverse reconstruction is still a tough problem that has plagued researchers in a related area. The ill-posedness of inverse reconstruction arises from insufficient measurements and modeling errors, so that the inverse reconstruction cannot be solved directly. In this study, an l{sub 1/2} regularization based numerical method was developed for effective reconstruction of BLT. In the method, the inverse reconstruction of BLT was constrained into an l{sub 1/2} regularization problem, and then the weighted interior-point algorithm (WIPA) was applied to solve the problem through transforming it into obtaining the solution of a series of l{sub 1} regularizers. The feasibility and effectiveness of the proposed method were demonstrated with numerical simulations on a digital mouse. Stability verification experiments further illustrated the robustness of the proposed method for different levels of Gaussian noise.

  14. A Monte-Carlo-Based Network Method for Source Positioning in Bioluminescence Tomography

    OpenAIRE

    Zhun Xu; Xiaolei Song; Xiaomeng Zhang; Jing Bai

    2007-01-01

    We present an approach based on the improved Levenberg Marquardt (LM) algorithm of backpropagation (BP) neural network to estimate the light source position in bioluminescent imaging. For solving the forward problem, the table-based random sampling algorithm (TBRS), a fast Monte Carlo simulation method ...

  15. Hybrid radiosity-SP3 equation based bioluminescence tomography reconstruction for turbid medium with low- and non-scattering regions

    Science.gov (United States)

    Chen, Xueli; Zhang, Qitan; Yang, Defu; Liang, Jimin

    2014-01-01

    To provide an ideal solution for a specific problem of gastric cancer detection in which low-scattering regions simultaneously existed with both the non- and high-scattering regions, a novel hybrid radiosity-SP3 equation based reconstruction algorithm for bioluminescence tomography was proposed in this paper. In the algorithm, the third-order simplified spherical harmonics approximation (SP3) was combined with the radiosity equation to describe the bioluminescent light propagation in tissues, which provided acceptable accuracy for the turbid medium with both low- and non-scattering regions. The performance of the algorithm was evaluated with digital mouse based simulations and a gastric cancer-bearing mouse based in situ experiment. Primary results demonstrated the feasibility and superiority of the proposed algorithm for the turbid medium with low- and non-scattering regions.

  16. Hybrid radiosity-SP3 equation based bioluminescence tomography reconstruction for turbid medium with low- and non-scattering regions

    International Nuclear Information System (INIS)

    To provide an ideal solution for a specific problem of gastric cancer detection in which low-scattering regions simultaneously existed with both the non- and high-scattering regions, a novel hybrid radiosity-SP3 equation based reconstruction algorithm for bioluminescence tomography was proposed in this paper. In the algorithm, the third-order simplified spherical harmonics approximation (SP3) was combined with the radiosity equation to describe the bioluminescent light propagation in tissues, which provided acceptable accuracy for the turbid medium with both low- and non-scattering regions. The performance of the algorithm was evaluated with digital mouse based simulations and a gastric cancer-bearing mouse based in situ experiment. Primary results demonstrated the feasibility and superiority of the proposed algorithm for the turbid medium with low- and non-scattering regions

  17. A measurement-based analytical approach to the bioluminescence tomography problem

    Science.gov (United States)

    Erkol, Hakan; Demirkiran, Aytac; Kipergil, Esra-Aytac; Uluc, Nasire; Unlu, Mehmet B.

    2014-03-01

    This work presents an analytical approach for the solution of the tissue diffusion equation based on the bound- ary measurements. We consider a bioluminescent point source in both homogeneous and heterogeneous circular turbid media. The point source is described by the Dirac delta function. Analytical expressions for the strength and position of the point source are obtained introducing boundary measurements and then applying appropriate boundary conditions. In addition, numerical simulations are performed for the position of the source. Calculations show that that the analytical results are in a good accordance with the numerical results.

  18. Experimental Study on Bioluminescence Tomography with Multimodality Fusion

    OpenAIRE

    Lv, Yujie; Tian, Jie; Cong, Wenxiang; Wang, Ge

    2007-01-01

    To verify the influence of a priori information on the nonuniqueness problem of bioluminescence tomography (BLT), the multimodality imaging fusion based BLT experiment is performed by multiview noncontact detection mode, which incorporates the anatomical information obtained by the microCT scanner and the background optical properties based on diffuse reflectance measurements. In the reconstruction procedure, the utilization of adaptive finite element methods (FEMs) and a priori permissible s...

  19. Moment searching algorithm for bioluminescence tomography

    Institute of Scientific and Technical Information of China (English)

    Ludong Jin; Yan Wu; Jie Tian; Heyu Huang; Xiaochao Qu

    2009-01-01

    To avoid the ill-posedness in the inverse problem of bioluminescence tomography, a moment searching algorithm fusing the finite element method (FEM) with the moment concept in theoretical mechanics is developed. In the algorithm, the source's information is mapped to the surface photon flux density by FEM, and the source's position is modified with the feedback through the algorithm of barycenter searching, which makes full use of the position information of the photon flux density on surface. The position is modified in every iterative step and will finally converge to the real source's value theoretically.

  20. Hybrid radiosity-SP{sub 3} equation based bioluminescence tomography reconstruction for turbid medium with low- and non-scattering regions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xueli, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn; Zhang, Qitan; Yang, Defu; Liang, Jimin, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn [School of Life Science and Technology, Xidian University, Xi' an, Shaanxi 710071 (China)

    2014-01-14

    To provide an ideal solution for a specific problem of gastric cancer detection in which low-scattering regions simultaneously existed with both the non- and high-scattering regions, a novel hybrid radiosity-SP{sub 3} equation based reconstruction algorithm for bioluminescence tomography was proposed in this paper. In the algorithm, the third-order simplified spherical harmonics approximation (SP{sub 3}) was combined with the radiosity equation to describe the bioluminescent light propagation in tissues, which provided acceptable accuracy for the turbid medium with both low- and non-scattering regions. The performance of the algorithm was evaluated with digital mouse based simulations and a gastric cancer-bearing mouse based in situ experiment. Primary results demonstrated the feasibility and superiority of the proposed algorithm for the turbid medium with low- and non-scattering regions.

  1. Ultrasound-modulated bioluminescence tomography

    Science.gov (United States)

    Bal, Guillaume; Schotland, John C.

    2014-03-01

    We propose a method to reconstruct the density of a luminescent source in a highly scattering medium from ultrasound-modulated optical measurements. Our approach is based on the solution to a hybrid inverse source problem for the diffusion equation.

  2. Experimental Study on Bioluminescence Tomography with Multimodality Fusion

    Directory of Open Access Journals (Sweden)

    Yujie Lv

    2007-01-01

    Full Text Available To verify the influence of a priori information on the nonuniqueness problem of bioluminescence tomography (BLT, the multimodality imaging fusion based BLT experiment is performed by multiview noncontact detection mode, which incorporates the anatomical information obtained by the microCT scanner and the background optical properties based on diffuse reflectance measurements. In the reconstruction procedure, the utilization of adaptive finite element methods (FEMs and a priori permissible source region refines the reconstructed results and improves numerical robustness and efficiency. The comparison between the absence and employment of a priori information shows that multimodality imaging fusion is essential to quantitative BLT reconstruction.

  3. BIOLUMINESCENCE TOMOGRAPHY: BIOMEDICAL BACKGROUND, MATHEMATICAL THEORY, AND NUMERICAL APPROXIMATION

    Institute of Scientific and Technical Information of China (English)

    Weimin Han; Ce Wang

    2008-01-01

    Over the last couple of years molecular imaging has been rapidly developed to study physiological and pathological processes in vivo at the cellular and molecular levels. Among molecular imaging modalities, optical imaging stands out for its unique advantages, especially performance and cost-effectiveness. Bioluminescence tomography (BLT) is an emerging optical imaging mode with promising biomedical advantages. In this survey paper, we explain the biomedical significance of BLT, summarize theoretical results on the analysis and numerical solution of a diffusion based BLT model, and comment on a few extensions for the study of BLT.

  4. An adaptive regularization parameter choice strategy for multispectral bioluminescence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jinchao; Qin Chenghu; Jia Kebin; Han Dong; Liu Kai; Zhu Shouping; Yang Xin; Tian Jie [Medical Image Processing Group, Institute of Automation, Chinese Academy of Sciences, P. O. Box 2728, Beijing 100190 (China); College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Medical Image Processing Group, Institute of Automation, Chinese Academy of Sciences, P. O. Box 2728, Beijing 100190 (China); Medical Image Processing Group, Institute of Automation, Chinese Academy of Sciences, P. O. Box 2728, Beijing 100190 (China) and School of Life Sciences and Technology, Xidian University, Xi' an 710071 (China)

    2011-11-15

    Purpose: Bioluminescence tomography (BLT) provides an effective tool for monitoring physiological and pathological activities in vivo. However, the measured data in bioluminescence imaging are corrupted by noise. Therefore, regularization methods are commonly used to find a regularized solution. Nevertheless, for the quality of the reconstructed bioluminescent source obtained by regularization methods, the choice of the regularization parameters is crucial. To date, the selection of regularization parameters remains challenging. With regards to the above problems, the authors proposed a BLT reconstruction algorithm with an adaptive parameter choice rule. Methods: The proposed reconstruction algorithm uses a diffusion equation for modeling the bioluminescent photon transport. The diffusion equation is solved with a finite element method. Computed tomography (CT) images provide anatomical information regarding the geometry of the small animal and its internal organs. To reduce the ill-posedness of BLT, spectral information and the optimal permissible source region are employed. Then, the relationship between the unknown source distribution and multiview and multispectral boundary measurements is established based on the finite element method and the optimal permissible source region. Since the measured data are noisy, the BLT reconstruction is formulated as l{sub 2} data fidelity and a general regularization term. When choosing the regularization parameters for BLT, an efficient model function approach is proposed, which does not require knowledge of the noise level. This approach only requests the computation of the residual and regularized solution norm. With this knowledge, we construct the model function to approximate the objective function, and the regularization parameter is updated iteratively. Results: First, the micro-CT based mouse phantom was used for simulation verification. Simulation experiments were used to illustrate why multispectral data were used

  5. An adaptive regularization parameter choice strategy for multispectral bioluminescence tomography

    International Nuclear Information System (INIS)

    Purpose: Bioluminescence tomography (BLT) provides an effective tool for monitoring physiological and pathological activities in vivo. However, the measured data in bioluminescence imaging are corrupted by noise. Therefore, regularization methods are commonly used to find a regularized solution. Nevertheless, for the quality of the reconstructed bioluminescent source obtained by regularization methods, the choice of the regularization parameters is crucial. To date, the selection of regularization parameters remains challenging. With regards to the above problems, the authors proposed a BLT reconstruction algorithm with an adaptive parameter choice rule. Methods: The proposed reconstruction algorithm uses a diffusion equation for modeling the bioluminescent photon transport. The diffusion equation is solved with a finite element method. Computed tomography (CT) images provide anatomical information regarding the geometry of the small animal and its internal organs. To reduce the ill-posedness of BLT, spectral information and the optimal permissible source region are employed. Then, the relationship between the unknown source distribution and multiview and multispectral boundary measurements is established based on the finite element method and the optimal permissible source region. Since the measured data are noisy, the BLT reconstruction is formulated as l2 data fidelity and a general regularization term. When choosing the regularization parameters for BLT, an efficient model function approach is proposed, which does not require knowledge of the noise level. This approach only requests the computation of the residual and regularized solution norm. With this knowledge, we construct the model function to approximate the objective function, and the regularization parameter is updated iteratively. Results: First, the micro-CT based mouse phantom was used for simulation verification. Simulation experiments were used to illustrate why multispectral data were used rather

  6. Enhanced Landweber algorithm via Bregman iterations for bioluminescence tomography

    Science.gov (United States)

    Xia, Yi; Zhang, Meng

    2014-09-01

    Bioluminescence tomography (BLT) is an important optical molecular imaging modality aimed at visualizing physiological and pathological processes at cellular and molecular levels. While the forward process of light propagation is described by the diffusion approximation to radiative transfer equation, BLT is the inverse problem to reconstruct the 3D localization and quantification of internal bioluminescent sources distribution. Due to the inherent ill-posedness of the BLT problem, regularization is generally indispensable to obtain more favorable reconstruction. In particular, total variation (TV) regularization is known to be effective for piecewise-constant source distribution which can permit sharp discontinuities and preserve edges. However, total variation regularization generally suffers from the unsatisfactory staircasing effect. In this work, we introduce the Bregman iterative regularization to alleviate this degeneration and enhance the numerical reconstruction of BLT. Based on the existing Landweber method (LM), we put forward the Bregman-LM-TV algorithm for BLT. Numerical experiments are carried out and preliminary simulation results are reported to evaluate the proposed algorithms. It is found that Bregman-LM-TV can significantly outperform the individual Landweber method for BLT when the source distribution is piecewise-constant.

  7. Spectrally resolved bioluminescence tomography with the third-order simplified spherical harmonics approximation

    International Nuclear Information System (INIS)

    Bioluminescence imaging has been extensively applied to in vivo small animal imaging. Quantitative three-dimensional bioluminescent source information obtained by using bioluminescence tomography can directly and much more accurately reflect biological changes as opposed to planar bioluminescence imaging. Preliminary simulated and experimental reconstruction results demonstrate the feasibility and promise of bioluminescence tomography. However, the use of multiple approximations, particularly the diffusion approximation theory, affects the quality of in vivo small animal-based image reconstructions. In the development of new reconstruction algorithms, high-order approximation models of the radiative transfer equation and spectrally resolved data introduce new challenges to the reconstruction algorithm and speed. In this paper, an SP3-based (the third-order simplified spherical harmonics approximation) spectrally resolved reconstruction algorithm is proposed. The simple linear relationship between the unknown source distribution and the spectrally resolved data is established in this algorithm. A parallel version of this algorithm is realized, making BLT reconstruction feasible for the whole body of small animals especially for fine spatial domain discretization. In simulation validations, the proposed algorithm shows improved reconstruction quality compared with diffusion approximation-based methods when high absorption, superficial sources and detection modes are considered. In addition, comparisons between fine and coarse mesh-based BLT reconstructions show the effects of numerical errors in reconstruction image quality. Finally, BLT reconstructions using in vivo mouse experiments further demonstrate the potential and effectiveness of the SP3-based reconstruction algorithm.

  8. A Nisin Bioassay Based on Bioluminescence

    OpenAIRE

    Wahlström, G.; Saris, P. E. J.

    1999-01-01

    A Lactococcus lactis subsp. lactis strain that can sense the bacteriocin nisin and transduce the signal into bioluminescence was constructed. By using this strain, a bioassay based on bioluminescence was developed for quantification of nisin, for detection of nisin in milk, and for identification of nisin-producing strains. As little as 0.0125 ng of nisin per ml was detected within 3 h by this bioluminescence assay. This detection limit was lower than in previously described methods.

  9. Mathematical Study and Numerical Simulation of Multispectral Bioluminescence Tomography

    OpenAIRE

    Weimin Han; Wenxiang Cong; Ge Wang

    2006-01-01

    Multispectral bioluminescence tomography (BLT) attracts increasingly more attention in the area of optical molecular imaging. In this paper, we analyze the properties of the solutions to the regularized and discretized multispectral BLT problems. First, we show the solution existence, uniqueness, and its continuous dependence on the data. Then, we introduce stable numerical schemes and derive error estimates for numerical solutions. We report some numerical results to illust...

  10. Hyperspectral and multispectral bioluminescence optical tomography for small animal imaging

    International Nuclear Information System (INIS)

    For bioluminescence imaging studies in small animals, it is important to be able to accurately localize the three-dimensional (3D) distribution of the underlying bioluminescent source. The spectrum of light produced by the source that escapes the subject varies with the depth of the emission source because of the wavelength-dependence of the optical properties of tissue. Consequently, multispectral or hyperspectral data acquisition should help in the 3D localization of deep sources. In this paper, we describe a framework for fully 3D bioluminescence tomographic image acquisition and reconstruction that exploits spectral information. We describe regularized tomographic reconstruction techniques that use semi-infinite slab or FEM-based diffusion approximations of photon transport through turbid media. Singular value decomposition analysis was used for data dimensionality reduction and to illustrate the advantage of using hyperspectral rather than achromatic data. Simulation studies in an atlas-mouse geometry indicated that sub-millimeter resolution may be attainable given accurate knowledge of the optical properties of the animal. A fixed arrangement of mirrors and a single CCD camera were used for simultaneous acquisition of multispectral imaging data over most of the surface of the animal. Phantom studies conducted using this system demonstrated our ability to accurately localize deep point-like sources and show that a resolution of 1.5 to 2.2 mm for depths up to 6 mm can be achieved. We also include an in vivo study of a mouse with a brain tumour expressing firefly luciferase. Co-registration of the reconstructed 3D bioluminescent image with magnetic resonance images indicated good anatomical localization of the tumour

  11. Algorithm for localized adaptive diffuse optical tomography and its application in bioluminescence tomography

    Science.gov (United States)

    Naser, Mohamed A.; Patterson, Michael S.; Wong, John W.

    2014-04-01

    A reconstruction algorithm for diffuse optical tomography based on diffusion theory and finite element method is described. The algorithm reconstructs the optical properties in a permissible domain or region-of-interest to reduce the number of unknowns. The algorithm can be used to reconstruct optical properties for a segmented object (where a CT-scan or MRI is available) or a non-segmented object. For the latter, an adaptive segmentation algorithm merges contiguous regions with similar optical properties thereby reducing the number of unknowns. In calculating the Jacobian matrix the algorithm uses an efficient direct method so the required time is comparable to that needed for a single forward calculation. The reconstructed optical properties using segmented, non-segmented, and adaptively segmented 3D mouse anatomy (MOBY) are used to perform bioluminescence tomography (BLT) for two simulated internal sources. The BLT results suggest that the accuracy of reconstruction of total source power obtained without the segmentation provided by an auxiliary imaging method such as x-ray CT is comparable to that obtained when using perfect segmentation.

  12. Algorithm for localized adaptive diffuse optical tomography and its application in bioluminescence tomography

    International Nuclear Information System (INIS)

    A reconstruction algorithm for diffuse optical tomography based on diffusion theory and finite element method is described. The algorithm reconstructs the optical properties in a permissible domain or region-of-interest to reduce the number of unknowns. The algorithm can be used to reconstruct optical properties for a segmented object (where a CT-scan or MRI is available) or a non-segmented object. For the latter, an adaptive segmentation algorithm merges contiguous regions with similar optical properties thereby reducing the number of unknowns. In calculating the Jacobian matrix the algorithm uses an efficient direct method so the required time is comparable to that needed for a single forward calculation. The reconstructed optical properties using segmented, non-segmented, and adaptively segmented 3D mouse anatomy (MOBY) are used to perform bioluminescence tomography (BLT) for two simulated internal sources. The BLT results suggest that the accuracy of reconstruction of total source power obtained without the segmentation provided by an auxiliary imaging method such as x-ray CT is comparable to that obtained when using perfect segmentation. (paper)

  13. Automatic Segmentation Framework of Building Anatomical Mouse Model for Bioluminescence Tomography

    OpenAIRE

    Abdullah Alali

    2013-01-01

    Bioluminescence tomography is known as a highly ill-posed inverse problem. To improve the reconstruction performance by introducing anatomical structures as a priori knowledge, an automatic segmentation framework has been proposed in this paper to extract the mouse whole-body organs and tissues, which enables to build up a heterogeneous mouse model for reconstruction of bioluminescence tomography. Finally, an in vivo mouse experiment has been conducted to evaluate this framework by using an X...

  14. Bioluminescence.

    Science.gov (United States)

    Jones, M. Gail

    1993-01-01

    Describes bioluminescence and the chemistry of how it occurs. Presents information for conducting the following classroom activities: (1) firefly mimic; (2) modeling deep-sea fish; (3) sea fireflies; and (4) the chemistry of light. (PR)

  15. A multi-phase level set framework for source reconstruction in bioluminescence tomography

    International Nuclear Information System (INIS)

    We propose a novel multi-phase level set algorithm for solving the inverse problem of bioluminescence tomography. The distribution of unknown interior source is considered as piecewise constant and represented by using multiple level set functions. The localization of interior bioluminescence source is implemented by tracing the evolution of level set function. An alternate search scheme is incorporated to ensure the global optimal of reconstruction. Both numerical and physical experiments are performed to evaluate the developed level set reconstruction method. Reconstruction results show that the proposed method can stably resolve the interior source of bioluminescence tomography.

  16. Spectrally resolved bioluminescence tomography with adaptive finite element analysis: methodology and simulation

    International Nuclear Information System (INIS)

    As a molecular imaging technique, bioluminescence tomography (BLT) with its highly sensitive detection and facile operation can significantly reveal molecular and cellular information in vivo at the whole-body small animal level. However, because of complex photon transportation in biological tissue and boundary detection data with high noise, bioluminescent sources in deeper positions generally cannot be localized. In our previous work, we used achromatic or monochromatic measurements and an a priori permissible source region strategy to develop a multilevel adaptive finite-element algorithm. In this paper, we propose a spectrally solved tomographic algorithm with a posteriori permissible source region selection. Multispectral measurements, and anatomical and optical information first deal with the nonuniqueness of BLT and constrain the possible solution of source reconstruction. The use of adaptive mesh refinement and permissible source region based on a posteriori measures not only avoids the dimension disaster arising from the multispectral measured data but also reduces the ill-posedness of BLT and therefore improves the reconstruction quality. Reconsideration of the optimization method and related modifications further enhance reconstruction robustness and efficiency. We also incorporate into the method some improvements for reducing computational burdens. Finally, using a whole-body virtual mouse phantom, we demonstrate the capability of the proposed BLT algorithm to reconstruct accurately bioluminescent sources in deeper positions. In terms of optical property errors and two sources of discernment in deeper positions, this BLT algorithm represents the unique predominance for BLT reconstruction

  17. In vivo bioluminescence tomography with a blocking-off finite-difference SP3 method and MRI∕CT coregistration

    OpenAIRE

    Klose, Alexander D.; Beattie, Bradley J.; Dehghani, Hamid; Vider, Lena; Le, Carl; Ponomarev, Vladimir; Blasberg, Ronald

    2009-01-01

    Purpose: Bioluminescence imaging is a research tool for studying gene expression levels in small animal models of human disease. Bioluminescence light, however, is strongly scattered in biological tissue and no direct image of the light-emitting reporter probe’s location can be obtained. Therefore, the authors have developed a linear image reconstruction method for bioluminescence tomography (BLT) that recovers the three-dimensional spatial bioluminescent source distribution in small animals.

  18. Multi-atlas registration and adaptive hexahedral voxel discretization for fast bioluminescence tomography.

    Science.gov (United States)

    Ren, Shenghan; Hu, Haihong; Li, Gen; Cao, Xu; Zhu, Shouping; Chen, Xueli; Liang, Jimin

    2016-04-01

    Bioluminescence tomography (BLT) has been a valuable optical molecular imaging technique to non-invasively depict the cellular and molecular processes in living animals with high sensitivity and specificity. Due to the inherent ill-posedness of BLT, a priori information of anatomical structure is usually incorporated into the reconstruction. The structural information is usually provided by computed tomography (CT) or magnetic resonance imaging (MRI). In order to obtain better quantitative results, BLT reconstruction with heterogeneous tissues needs to segment the internal organs and discretize them into meshes with the finite element method (FEM). It is time-consuming and difficult to handle the segmentation and discretization problems. In this paper, we present a fast reconstruction method for BLT based on multi-atlas registration and adaptive voxel discretization to relieve the complicated data processing procedure involved in the hybrid BLT/CT system. A multi-atlas registration method is first adopted to estimate the internal organ distribution of the imaged animal. Then, the animal volume is adaptively discretized into hexahedral voxels, which are fed into FEM for the following BLT reconstruction. The proposed method is validated in both numerical simulation and an in vivo study. The results demonstrate that the proposed method can reconstruct the bioluminescence source efficiently with satisfactory accuracy. PMID:27446674

  19. Multi-atlas registration and adaptive hexahedral voxel discretization for fast bioluminescence tomography

    Science.gov (United States)

    Ren, Shenghan; Hu, Haihong; Li, Gen; Cao, Xu; Zhu, Shouping; Chen, Xueli; Liang, Jimin

    2016-01-01

    Bioluminescence tomography (BLT) has been a valuable optical molecular imaging technique to non-invasively depict the cellular and molecular processes in living animals with high sensitivity and specificity. Due to the inherent ill-posedness of BLT, a priori information of anatomical structure is usually incorporated into the reconstruction. The structural information is usually provided by computed tomography (CT) or magnetic resonance imaging (MRI). In order to obtain better quantitative results, BLT reconstruction with heterogeneous tissues needs to segment the internal organs and discretize them into meshes with the finite element method (FEM). It is time-consuming and difficult to handle the segmentation and discretization problems. In this paper, we present a fast reconstruction method for BLT based on multi-atlas registration and adaptive voxel discretization to relieve the complicated data processing procedure involved in the hybrid BLT/CT system. A multi-atlas registration method is first adopted to estimate the internal organ distribution of the imaged animal. Then, the animal volume is adaptively discretized into hexahedral voxels, which are fed into FEM for the following BLT reconstruction. The proposed method is validated in both numerical simulation and an in vivo study. The results demonstrate that the proposed method can reconstruct the bioluminescence source efficiently with satisfactory accuracy.

  20. Design and implementation of an optical simulation environment for bioluminescent tomography studies

    Institute of Scientific and Technical Information of China (English)

    LI Hui; TIAN Jie; LUO Jie; L(U) Yujie; CONG Wenxiang; WANG Ge

    2007-01-01

    As a challenging task for bioluminescent tomography simulation, a virtual optical environment is needed to solve the forward problem accurately, that is, to achieve a high precision for bioluminescent signal synthesis on the external body surface of a small animal. The molecular optical simulation environment named MOSE is implemented using the C + + programming language and the OpenGL techniques, including a user-friendly interface with interactive tools facilitating users' operations. The accuracy of the virtual optical environment is verified by error analysis of mesh simplification and comparison between MOSE results and experimental data. This virtual optical environment is accurate, flexible and efficient to simulate the photon propagation in complicated tissues, which has a great potential to become a software platform for bioluminescent tomography studies and other molecular imaging applications.

  1. Total variation regularization for bioluminescence tomography with the split Bregman method.

    Science.gov (United States)

    Feng, Jinchao; Qin, Chenghu; Jia, Kebin; Zhu, Shouping; Liu, Kai; Han, Dong; Yang, Xin; Gao, Quansheng; Tian, Jie

    2012-07-01

    Regularization methods have been broadly applied to bioluminescence tomography (BLT) to obtain stable solutions, including l2 and l1 regularizations. However, l2 regularization can oversmooth reconstructed images and l1 regularization may sparsify the source distribution, which degrades image quality. In this paper, the use of total variation (TV) regularization in BLT is investigated. Since a nonnegativity constraint can lead to improved image quality, the nonnegative constraint should be considered in BLT. However, TV regularization with a nonnegativity constraint is extremely difficult to solve due to its nondifferentiability and nonlinearity. The aim of this work is to validate the split Bregman method to minimize the TV regularization problem with a nonnegativity constraint for BLT. The performance of split Bregman-resolved TV (SBRTV) based BLT reconstruction algorithm was verified with numerical and in vivo experiments. Experimental results demonstrate that the SBRTV regularization can provide better regularization quality over l2 and l1 regularizations.

  2. The First Bioluminescence Tomography System for Simultaneous Acquisition of Multiview and Multispectral Data

    Directory of Open Access Journals (Sweden)

    Ge Wang

    2006-01-01

    Full Text Available We describe the system design of the first bioluminescence tomography (BLT system for parallel acquisition of multiple bioluminescent views around a mouse in a number of spectral channels simultaneously. The primary component of this BLT system is a novel mirror module and a unique mouse holder. The mirror module consists of a mounting plate and four mirrors with stages. These mirror stages are right triangular blocks symmetrically arranged and attached to the mounting plate such that the hypotenuse surfaces of the triangular blocks all make 45∘ to the plate surface. The cylindrical/polygonal mouse holder has semitransparent rainbow bands on its side surface for the acquisition of spectrally resolved data. Numerical studies and experiments are performed to demonstrate the feasibility of this system. It is shown that bioluminescent signals collected using our system can produce a similar BLT reconstruction quality while reducing the data acquisition time, as compared to the sequential data acquisition mode.

  3. Three-dimensional localization of in vivo bioluminescent source based on multispectral imaging

    Science.gov (United States)

    Feng, Jinchao; Jia, Kebin; Tian, Jie; Yan, Guorui; Zhu, Shouping

    2009-02-01

    Bioluminescence tomography (BLT) is a novel in vivo technique in small animal studies, which can reveal the molecular and cellular information at the whole-body small animal level. At present, there is an increasing interest in multispectral bioluminescence tomography, since multispectral data acquisition could improve the BLT performance significantly. In view to the ill-posedness of BLT problem, we develop an optimal permissible source region strategy to constrain the possible solution of the source by utilizing spectrum character of bioluminescent source. Then a linear system to link the measured data with the unknown light source variables is established by utilizing the optimal permissible region strategy based on adaptive finite element analysis. Furthermore, singular value decomposition analysis is used for data dimensionality reduction and improving computational efficiency in multispectral case. The reconstructed speed and stability benefit from adaptive finite element, the permissible region strategy and singular value decomposition. In the numerical simulation, the heterogeneous phantom experiment has been used to evaluate the performance of the proposed algorithm with the Monte Carlo based synthetic data. The reconstruction results demonstrate the merits and potential of our methodology for localizing bioluminescent source.

  4. Small animal fluorescence and bioluminescence tomography: a review of approaches, algorithms and technology update

    Science.gov (United States)

    Darne, Chinmay; Lu, Yujie; Sevick-Muraca, Eva M.

    2014-01-01

    Emerging fluorescence and bioluminescence tomography approaches have several common, yet several distinct features from established emission tomographies of PET and SPECT. Although both nuclear and optical imaging modalities involve counting of photons, nuclear imaging techniques collect the emitted high energy (100-511 keV) photons after radioactive decay of radionuclides while optical techniques count low-energy (1.5-4.1 eV) photons that are scattered and absorbed by tissues requiring models of light transport for quantitative image reconstruction. Fluorescence imaging has been recently translated into clinic demonstrating high sensitivity, modest tissue penetration depth, and fast, millisecond image acquisition times. As a consequence, the promise of quantitative optical tomography as a complement of small animal PET and SPECT remains high. In this review, we summarize the different instrumentation, methodological approaches and schema for inverse image reconstructions for optical tomography, including luminescence and fluorescence modalities, and comment on limitations and key technological advances needed for further discovery research and translation.

  5. Small animal fluorescence and bioluminescence tomography: a review of approaches, algorithms and technology update

    International Nuclear Information System (INIS)

    Emerging fluorescence and bioluminescence tomography approaches have several common, yet several distinct features from established emission tomographies of PET and SPECT. Although both nuclear and optical imaging modalities involve counting of photons, nuclear imaging techniques collect the emitted high energy (100–511 keV) photons after radioactive decay of radionuclides while optical techniques count low-energy (1.5–4.1 eV) photons that are scattered and absorbed by tissues requiring models of light transport for quantitative image reconstruction. Fluorescence imaging has been recently translated into clinic demonstrating high sensitivity, modest tissue penetration depth, and fast, millisecond image acquisition times. As a consequence, the promise of quantitative optical tomography as a complement of small animal PET and SPECT remains high. In this review, we summarize the different instrumentation, methodological approaches and schema for inverse image reconstructions for optical tomography, including luminescence and fluorescence modalities, and comment on limitations and key technological advances needed for further discovery research and translation. (topical review)

  6. Accounting for filter bandwidth improves the quantitative accuracy of bioluminescence tomography

    Science.gov (United States)

    Taylor, Shelley L.; Mason, Suzannah K. G.; Glinton, Sophie L.; Cobbold, Mark; Dehghani, Hamid

    2015-09-01

    Bioluminescence imaging is a noninvasive technique whereby surface weighted images of luminescent probes within animals are used to characterize cell count and function. Traditionally, data are collected over the entire emission spectrum of the source using no filters and are used to evaluate cell count/function over the entire spectrum. Alternatively, multispectral data over several wavelengths can be incorporated to perform tomographic reconstruction of source location and intensity. However, bandpass filters used for multispectral data acquisition have a specific bandwidth, which is ignored in the reconstruction. In this work, ignoring the bandwidth is shown to introduce a dependence of the recovered source intensity on the bandwidth of the filters. A method of accounting for the bandwidth of filters used during multispectral data acquisition is presented and its efficacy in increasing the quantitative accuracy of bioluminescence tomography is demonstrated through simulation and experiment. It is demonstrated that while using filters with a large bandwidth can dramatically decrease the data acquisition time, if not accounted for, errors of up to 200% in quantitative accuracy are introduced in two-dimensional planar imaging, even after normalization. For tomographic imaging, the use of this method to account for filter bandwidth dramatically improves the quantitative accuracy.

  7. Multi-projection bioluminescence tomography guided system for small animal radiation research platform (SARRP)

    Science.gov (United States)

    Zhang, Bin; Iordachita, Iulian; Wong, John W.; Wang, Ken Kang-Hsin

    2016-03-01

    Cone beam computed tomography (CBCT) is limited in guiding irradiation for soft tissue targets. As a complementary imaging modality, bioluminescence tomography (BLT) provides strong soft tissue contrast. We developed a dual-use BLT system which consists of an optical assembly, a mobile cart and an independent mouse bed. The system is motorized which can easily dock onto an independent mouse bed operating as a standalone system for longitudinal bioluminescence imaging (BLI)/BLT studies and also dock onto the SARRP for on-line radiation guidance. Our initial tests for the system demonstrate that (i) the imaging depth is 28 mm, (ii) the optical background is sufficiently low and uniform, (iii) the non-uniform response of the optical imaging can be corrected by the flat field correction, and (iv) the imaging acquisition speed was improved by an average of 3.7 times faster than our previous systems. We also presented a geometry calibration procedure to map the planar BLIs acquired at multi-projections onto the surface of the CBCT image. The CBCT is required to generate the mesh for BLT reconstruction and used for treatment planning and radiation delivery. Feasibility study of the geometry calibration was performed on a manual-docking prototype. The mean and maximum mapping accuracy is 0.3 and 0.6 mm. The performance of the proposed motorized dual-use system is expected to be superior to that of the manual-docking prototype because of the mechanism stability. We anticipate the dual-use system as a highly efficient and cost-effective platform to facilitate optical imaging for preclinical radiation research.

  8. Fast iterative image reconstruction methods for fully 3D multispectral bioluminescence tomography

    International Nuclear Information System (INIS)

    We investigate fast iterative image reconstruction methods for fully 3D multispectral bioluminescence tomography for applications in small animal imaging. Our forward model uses a diffusion approximation for optically inhomogeneous tissue, which we solve using a finite element method (FEM). We examine two approaches to incorporating the forward model into the solution of the inverse problem. In a conventional direct calculation approach one computes the full forward model by repeated solution of the FEM problem, once for each potential source location. We describe an alternative on-the-fly approach where one does not explicitly solve for the full forward model. Instead, the solution to the forward problem is included implicitly in the formulation of the inverse problem, and the FEM problem is solved at each iteration for the current image estimate. We evaluate the convergence speeds of several representative iterative algorithms. We compare the computation cost of those two approaches, concluding that the on-the-fly approach can lead to substantial reductions in total cost when combined with a rapidly converging iterative algorithm

  9. Uptake kinetics and biodistribution of C-14-D-luciferin-a radiolabeled substrate for the firefly luciferase catalyzed bioluminescence reaction : impact on bioluminescence based reporter gene imaging

    NARCIS (Netherlands)

    Berger, Frank; Paulmurugan, Ramasamy; Bhaumik, Srabani; Gambhir, Sanjiv Sam

    2008-01-01

    Purpose Firefly luciferase catalyzes the oxidative decarboxylation of D-luciferin to oxyluciferin in the presence of cofactors, producing bioluminescence. This reaction is used in optical bioluminescence-based molecular imaging approaches to detect the expression of the firefly luciferase reporter g

  10. SU-E-T-20: A Novel Hybrid CBCT, Bioluminescence and Fluorescence Tomography System for Preclinical Radiation Research

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B; Eslami, S; Iordachita, I [Johns Hopkins University, Baltimore, Maryland (United States); Yang, Y [University of Miami School of Medicine, Miami, FL (United States); Patterson, M [Hamilton Regional Cancer Ctr., Hamilton, ON (Canada); Wong, J [Johns Hopkins University, Baltimore, MD (United States); Wang, K [Johns Hopkins Hospital, Baltimore, MD (United States)

    2014-06-01

    Purpose: A novel standalone bioluminescence and fluorescence tomography (BLT and FT) system equipped with high resolution CBCT has been built in our group. In this work, we present the system calibration method and validate our system in both phantom and in vivo environment. Methods: The CBCT is acquired by rotating the animal stage while keeping the x-ray source and detector panel static. The optical signal is reflected by the 3-mirror system to a multispectral filter set and then delivered to the CCD camera with f/1.4 lens mounted. Nine fibers passing through the stage and in contact with the mouse skin serve as the light sources for diffuse optical tomography (DOT) and FT. The anatomical information and optical properties acquired from the CBCT and DOT, respectively, are used as the priori information to improve the BLT/FT reconstruction accuracy. Flat field correction for the optical system was acquired at multiple wavelengths. A home-built phantom is used to register the optical and CBCT coordinates. An absolute calibration relating the CCD photon counts rate to the light fluence rate emitted at animal surface was developed to quantify the bioluminescence power or fluorophore concentration. Results: An optical inhomogeneous phantom with 2 light sources (3mm separation) imbedded is used to test the system. The optical signal is mapped onto the mesh generated from CBCT for optical reconstruction. Our preliminary results show that the center of mass can be reconstructed within 2.8mm accuracy. A live mouse with the light source imbedded is also used to validate our system. Liver or lung metastatic luminescence tumor model will be used for further testing. Conclusion: This hybrid system transforms preclinical research to a level that even sub-palpable volume of cells can be imaged rapidly and non-invasively, which largely extends the scope of radiobiological research. The research is supported by the NCI grant R01CA158100-01.

  11. SU-E-T-20: A Novel Hybrid CBCT, Bioluminescence and Fluorescence Tomography System for Preclinical Radiation Research

    International Nuclear Information System (INIS)

    Purpose: A novel standalone bioluminescence and fluorescence tomography (BLT and FT) system equipped with high resolution CBCT has been built in our group. In this work, we present the system calibration method and validate our system in both phantom and in vivo environment. Methods: The CBCT is acquired by rotating the animal stage while keeping the x-ray source and detector panel static. The optical signal is reflected by the 3-mirror system to a multispectral filter set and then delivered to the CCD camera with f/1.4 lens mounted. Nine fibers passing through the stage and in contact with the mouse skin serve as the light sources for diffuse optical tomography (DOT) and FT. The anatomical information and optical properties acquired from the CBCT and DOT, respectively, are used as the priori information to improve the BLT/FT reconstruction accuracy. Flat field correction for the optical system was acquired at multiple wavelengths. A home-built phantom is used to register the optical and CBCT coordinates. An absolute calibration relating the CCD photon counts rate to the light fluence rate emitted at animal surface was developed to quantify the bioluminescence power or fluorophore concentration. Results: An optical inhomogeneous phantom with 2 light sources (3mm separation) imbedded is used to test the system. The optical signal is mapped onto the mesh generated from CBCT for optical reconstruction. Our preliminary results show that the center of mass can be reconstructed within 2.8mm accuracy. A live mouse with the light source imbedded is also used to validate our system. Liver or lung metastatic luminescence tumor model will be used for further testing. Conclusion: This hybrid system transforms preclinical research to a level that even sub-palpable volume of cells can be imaged rapidly and non-invasively, which largely extends the scope of radiobiological research. The research is supported by the NCI grant R01CA158100-01

  12. SU-C-303-04: Evaluation of On- and Off-Line Bioluminescence Tomography System for Focal Irradiation Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B; Wang, K; Reyes, J; Tran, P; Wong, J [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD (United States); Iordachita, I [Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD (United States)

    2015-06-15

    Purpose: We have developed offline and on-board bioluminescence tomography(BLT) systems for the small animal radiation research platform(SARRP) for radiation guidance of soft tissue targets. We investigated the effectiveness of offline BLT guidance. Methods: CBCT is equipped on both the offline BLT system and SARRP that are 10 ft. apart. To evaluate the setup error during animal transport between the two systems, we implanted a luminescence source in the abdomen of anesthetized mice. Five mice were studied. After CBCT was acquired on both systems, source centers and correlation coefficients were calculated. CBCT was also used to generate object mesh for BLT reconstruction. To assess target localization, we compared the localization of the luminescence source based on (1)on-board SARRP BLT and CBCT, (2)offline BLT and CBCT, and (3)offline BLT and SARRP CBCT. The 3rd comparison examines if an offline BLT system can be used to guide radiation when there is minimal target contrast in CBCT. Results: Our CBCT results show the offset of the light source center can be maintained within 0.2 mm during animal transport. The center of mass(CoM) of the light source reconstructed by the offline BLT has an offset of 1.0 ± 0.4 mm from the ‘true’ CoM as derived from the SARRP CBCT. The results compare well with the offset of 1.0 ± 0.2 mm using on-line BLT. Conclusion: With CBCT information provided by the SARRP and effective animal immobilization during transport, these findings support the use of offline BLT in close vicinity for accurate soft tissue target localization for irradiation. However, the disadvantage of the off-line system is reduced efficiency as care is required to maintain stable animal transport. We envisage a dual use system where the on-board arrangement allows convenient access to CBCT and avoids disturbance of animal setup. The off-line capability would support standalone longitudinal imaging studies. The work is supported by NIH R01CA158100 and Xstrahl

  13. SU-C-303-04: Evaluation of On- and Off-Line Bioluminescence Tomography System for Focal Irradiation Guidance

    International Nuclear Information System (INIS)

    Purpose: We have developed offline and on-board bioluminescence tomography(BLT) systems for the small animal radiation research platform(SARRP) for radiation guidance of soft tissue targets. We investigated the effectiveness of offline BLT guidance. Methods: CBCT is equipped on both the offline BLT system and SARRP that are 10 ft. apart. To evaluate the setup error during animal transport between the two systems, we implanted a luminescence source in the abdomen of anesthetized mice. Five mice were studied. After CBCT was acquired on both systems, source centers and correlation coefficients were calculated. CBCT was also used to generate object mesh for BLT reconstruction. To assess target localization, we compared the localization of the luminescence source based on (1)on-board SARRP BLT and CBCT, (2)offline BLT and CBCT, and (3)offline BLT and SARRP CBCT. The 3rd comparison examines if an offline BLT system can be used to guide radiation when there is minimal target contrast in CBCT. Results: Our CBCT results show the offset of the light source center can be maintained within 0.2 mm during animal transport. The center of mass(CoM) of the light source reconstructed by the offline BLT has an offset of 1.0 ± 0.4 mm from the ‘true’ CoM as derived from the SARRP CBCT. The results compare well with the offset of 1.0 ± 0.2 mm using on-line BLT. Conclusion: With CBCT information provided by the SARRP and effective animal immobilization during transport, these findings support the use of offline BLT in close vicinity for accurate soft tissue target localization for irradiation. However, the disadvantage of the off-line system is reduced efficiency as care is required to maintain stable animal transport. We envisage a dual use system where the on-board arrangement allows convenient access to CBCT and avoids disturbance of animal setup. The off-line capability would support standalone longitudinal imaging studies. The work is supported by NIH R01CA158100 and Xstrahl

  14. Hybrid Multilevel Sparse Reconstruction for a Whole Domain Bioluminescence Tomography Using Adaptive Finite Element

    Directory of Open Access Journals (Sweden)

    Jingjing Yu

    2013-01-01

    Full Text Available Quantitative reconstruction of bioluminescent sources from boundary measurements is a challenging ill-posed inverse problem owing to the high degree of absorption and scattering of light through tissue. We present a hybrid multilevel reconstruction scheme by combining the ability of sparse regularization with the advantage of adaptive finite element method. In view of the characteristics of different discretization levels, two different inversion algorithms are employed on the initial coarse mesh and the succeeding ones to strike a balance between stability and efficiency. Numerical experiment results with a digital mouse model demonstrate that the proposed scheme can accurately localize and quantify source distribution while maintaining reconstruction stability and computational economy. The effectiveness of this hybrid reconstruction scheme is further confirmed with in vivo experiments.

  15. Bioluminescence-based imaging technique for pressure measurement in water

    Science.gov (United States)

    Watanabe, Yasunori; Tanaka, Yasufumi

    2011-07-01

    The dinoflagellate Pyrocystis lunula emits light in response to water motion. We developed a new imaging technique for measuring pressure using plankton that emits light in response to mechanical stimulation. The bioluminescence emitted by P. lunula was used to measure impact water pressure produced using weight-drop tests. The maximum mean luminescence intensity correlated with the maximum impact pressure that the cells receive when the circadian and diurnal biological rhythms are appropriately controlled. Thus, with appropriate calibration of experimentally determined parameters, the dynamic impact pressure can be estimated by measuring the cell-flash distribution. Statistical features of the evolution of flash intensity and the probability distribution during the impacting event, which are described by both biological and mechanical response parameters, are also discussed in this paper. The practical applicability of this bioluminescence imaging technique is examined through a water drop test. The maximum dynamic pressure, occurring at the impact of a water jet against a wall, was estimated from the flash intensity of the dinoflagellate.

  16. Simulation research on bioluminescence tomography%生物发光断层成像的仿真研究

    Institute of Scientific and Technical Information of China (English)

    刘勇; 齐树波; 方勇军; 陈锋

    2014-01-01

    目的:验证生物发光断层成像技术(bioluminescence tomography,BLT)成像的可行性并克服其成像的病态性.方法:采用BLT的前向数学模型和仿真实验结果进行分析.结果:仿真实验结果表明,基于多角度、非接触BLT成像系统(multi-view non-contact BLT imaging system),自发光源在成像体内的分布能够获得较为精确的解析,定位误差小于1 mm.结论:基于多角度、非接触的BLT成像系统,结合稀疏重建算法,能够在较少(6个)的角度下,获取较好的重建结果,有望为疾病早期诊断及药物研发等研究提供有力工具.

  17. Development of a rapid optic bacteria detecting system based on ATP bioluminescence

    Science.gov (United States)

    Liu, Jun Tao; Luo, JinPing; Liu, XiaoHong; Cai, XinXia

    2014-12-01

    A rapid optic bacteria detecting system based on the principle of Adenosine triphosphate(ATP) bioluminescence was presented in this paper. This system consisted of bioluminescence-based biosensor and the high-sensitivity optic meter. A photon counting photomultiplier tube (PMT) module was used to improve the detection sensitivity, and a NIOS II/f processor based on a Field Programmable Gate Array(FPGA) was used to control the system. In this work, Micrococcus luteus were chosen as the test sample. Several Micrococcus luteus suspension with different concentration was tested by both T2011 and plate counting method. By comparing the two group results, an calibration curve was obtained from the bioluminescence intensity for Micrococcus luteus in the range of 2.3×102 ~ 2.3×106 CFU/mL with a good correlation coefficient of 0.960. An impacting Air microorganism sampler was used to capture Airborne Bacteria, and 8 samples were collected in different place. The TBC results of 8 samples by T2011 were between 10 ~ 2×103 cfu/mL, consistent with that of plate counting method, which indicated that 8 samples were between 10 ~ 3×103 cfu/mL. For total airborne bacteria count was small, correlation coefficient was poor. Also no significant difference was found between T2011 and plate counting method by statistical analyses.

  18. Disposable bioluminescence-based biosensor for detection of bacterial count in food.

    Science.gov (United States)

    Luo, Jinping; Liu, Xiaohong; Tian, Qing; Yue, Weiwei; Zeng, Jing; Chen, Guangquan; Cai, Xinxia

    2009-11-01

    A biosensor for rapid detection of bacterial count based on adenosine 5'-triphosphate (ATP) bioluminescence has been developed. The biosensor is composed of a key sensitive element and a photomultiplier tube used as a detector element. The disposable sensitive element consists of a sampler, a cartridge where intracellular ATP is chemically extracted from bacteria, and a microtube where the extracted ATP reacts with the luciferin-luciferase reagent to produce bioluminescence. The bioluminescence signal is transformed into relevant electrical signal by the detector and further measured with a homemade luminometer. Parameters affecting the amount of the extracted ATP, including the types of ATP extractants, the concentrations of ATP extractant, and the relevant neutralizing reagent, were optimized. Under the optimal experimental conditions, the biosensor showed a linear response to standard bacteria in a concentration range from 10(3) to 10(8) colony-forming units (CFU) per milliliter with a correlation coefficient of 0.925 (n=22) within 5min. Moreover, the bacterial count of real food samples obtained by the biosensor correlated well with those by the conventional plate count method. The proposed biosensor, with characteristics of low cost, easy operation, and fast response, provides potential application to rapid evaluation of bacterial contamination in the food industry, environment monitoring, and other fields.

  19. Ultrasound modulated bioluminescence tomography and controllability of the radiative transport equation

    CERN Document Server

    Bal, Guillaume; Schotland, John C

    2015-01-01

    We propose a method to reconstruct the density of an optical source in a highly scattering medium from ultrasound-modulated optical measurements. Our approach is based on the solution to a hybrid inverse source problem for the radiative transport equation (RTE). A controllability result for the RTE plays an essential role in the analysis.

  20. BLProt: Prediction of bioluminescent proteins based on support vector machine and relieff feature selection

    KAUST Repository

    Kandaswamy, Krishna Kumar

    2011-08-17

    Background: Bioluminescence is a process in which light is emitted by a living organism. Most creatures that emit light are sea creatures, but some insects, plants, fungi etc, also emit light. The biotechnological application of bioluminescence has become routine and is considered essential for many medical and general technological advances. Identification of bioluminescent proteins is more challenging due to their poor similarity in sequence. So far, no specific method has been reported to identify bioluminescent proteins from primary sequence.Results: In this paper, we propose a novel predictive method that uses a Support Vector Machine (SVM) and physicochemical properties to predict bioluminescent proteins. BLProt was trained using a dataset consisting of 300 bioluminescent proteins and 300 non-bioluminescent proteins, and evaluated by an independent set of 141 bioluminescent proteins and 18202 non-bioluminescent proteins. To identify the most prominent features, we carried out feature selection with three different filter approaches, ReliefF, infogain, and mRMR. We selected five different feature subsets by decreasing the number of features, and the performance of each feature subset was evaluated.Conclusion: BLProt achieves 80% accuracy from training (5 fold cross-validations) and 80.06% accuracy from testing. The performance of BLProt was compared with BLAST and HMM. High prediction accuracy and successful prediction of hypothetical proteins suggests that BLProt can be a useful approach to identify bioluminescent proteins from sequence information, irrespective of their sequence similarity. 2011 Kandaswamy et al; licensee BioMed Central Ltd.

  1. Bioluminescence-based system for rapid detection of natural transformation.

    Science.gov (United States)

    Santala, Ville; Karp, Matti; Santala, Suvi

    2016-07-01

    Horizontal gene transfer plays a significant role in bacterial evolution and has major clinical importance. Thus, it is vital to understand the mechanisms and kinetics of genetic transformations. Natural transformation is the driving mechanism for horizontal gene transfer in diverse genera of bacteria. Our study introduces a simple and rapid method for the investigation of natural transformation. This highly sensitive system allows the detection of a transformation event directly from a bacterial population without any separation step or selection of cells. The system is based on the bacterial luciferase operon from Photorhabdus luminescens The studied molecular tools consist of the functional modules luxCDE and luxAB, which involve a replicative plasmid and an integrative gene cassette. A well-established host for bacterial genetic investigations, Acinetobacter baylyi ADP1, is used as the model bacterium. We show that natural transformation followed by homologous recombination or plasmid recircularization can be readily detected in both actively growing and static biofilm-like cultures, including very rare transformation events. The system allows the detection of natural transformation within 1 h of introducing sample DNA into the culture. The introduced method provides a convenient means to study the kinetics of natural transformation under variable conditions and perturbations. PMID:27190150

  2. Bioluminescence Imaging

    OpenAIRE

    Sadikot, Ruxana T.; Blackwell, Timothy S.

    2005-01-01

    Bioluminescence refers to the process of visible light emission in living organisms. Bioluminescence imaging is a powerful methodology that has been developed over the last decade as a tool for molecular imaging of small laboratory animals, enabling the study of ongoing biological processes in vivo. This form of optical imaging is low cost and noninvasive and facilitates real-time analysis of disease processes at the molecular level in living organisms. In this article, we provide a brief int...

  3. Uptake kinetics and biodistribution of 14C-d-luciferin - a radiolabeled substrate for the firefly luciferase catalyzed bioluminescence reaction: impact on bioluminescence based reporter gene imaging

    International Nuclear Information System (INIS)

    Firefly luciferase catalyzes the oxidative decarboxylation of d-luciferin to oxyluciferin in the presence of cofactors, producing bioluminescence. This reaction is used in optical bioluminescence-based molecular imaging approaches to detect the expression of the firefly luciferase reporter gene. Biokinetics and distribution of the substrate most likely have a significant impact on levels of light signal and therefore need to be investigated. Benzene ring 14C(U)-labeled d-luciferin was utilized. Cell uptake and efflux assays, murine biodistribution, autoradiography and CCD-camera based optical bioluminescence imaging were carried out to examine the in vitro and in vivo characteristics of the tracer in cell culture and in living mice respectively. Radiolabeled and unlabeled d-luciferin revealed comparable levels of light emission when incubated with equivalent amounts of the firefly luciferase enzyme. Cell uptake assays in pCMV-luciferase-transfected cells showed slow trapping of the tracer and relatively low uptake values (up to 22.9-fold higher in firefly luciferase gene-transfected vs. nontransfected cells, p=0.0002). Biodistribution studies in living mice after tail-vein injection of 14C-d-luciferin demonstrated inhomogeneous tracer distribution with early predominant high radioactivity levels in kidneys (10.6% injected dose [ID]/g) and liver (11.9% ID/g), followed at later time points by the bladder (up to 81.3% ID/g) and small intestine (6.5% ID/g), reflecting the elimination routes of the tracer. Kinetics and uptake levels profoundly differed when using alternate injection routes (intravenous versus intraperitoneal). No clear trapping of 14C-d-luciferin in firefly luciferase-expressing tissues could be observed in vivo. The data obtained with 14C-d-luciferin provide insights into the dynamics of d-luciferin cell uptake, intracellular accumulation, and efflux. Results of the biodistribution and autoradiographic studies should be useful for optimizing and

  4. Bioluminescence-based method for measuring assimilable organic carbon in pretreatment water for reverse osmosis membrane desalination.

    Science.gov (United States)

    Weinrich, Lauren A; Schneider, Orren D; LeChevallier, Mark W

    2011-02-01

    A bioluminescence-based assimilable organic carbon (AOC) test was developed for determining the biological growth potential of seawater within the reverse osmosis desalination pretreatment process. The test uses Vibrio harveyi, a marine organism that exhibits constitutive luminescence and is nutritionally robust. AOC was measured in both a pilot plant and a full-scale desalination plant pretreatment.

  5. Destabilized bioluminescent proteins

    Science.gov (United States)

    Allen, Michael S.; Rakesh, Gupta; Gary, Sayler S.

    2007-07-31

    Purified nucleic acids, vectors and cells containing a gene cassette encoding at least one modified bioluminescent protein, wherein the modification includes the addition of a peptide sequence. The duration of bioluminescence emitted by the modified bioluminescent protein is shorter than the duration of bioluminescence emitted by an unmodified form of the bioluminescent protein.

  6. ATP binding cassette transporters modulate both coelenterazine- and D-luciferin- based bioluminescence imaging

    OpenAIRE

    Huang, Ruimin; Vider, Jelena; Serganova, Inna; Blasberg, Ronald G.

    2011-01-01

    Bioluminescence imaging (BLI) of luciferase reporters provides a cost-effective and sensitive means to image biological processes. However, transport of luciferase substrates across the cell membrane does affect BLI-readout-intensity from intact living cells.

  7. Bioluminescence flow visualization in the ocean: an initial strategy based on laboratory experiments

    Science.gov (United States)

    Rohr, Jim; Hyman, Mark; Fallon, Stewart; Latz, Michael I.

    2002-11-01

    Observations of flow-stimulated bioluminescence have been recorded for centuries throughout the world's oceans. The present study explores, within a laboratory context, the use of naturally occurring bioluminescence as a strategy towards visualizing oceanic flow fields. The response of luminescent plankton to quantifiable levels of flow agitation was investigated in fully developed pipe flow. With two different pipe flow apparatus and freshly collected mixed plankton samples obtained over a year at two separate locations, several repeatable response patterns were identified. Threshold levels for bioluminescence stimulation occurred in laminar flow with wall shear stress levels generally between 1 and 2 dyn cm -2 (0.1-0.2 N m -2), equivalent to energy dissipation per unit mass values of 10 2-10 3 cm 2 s -3 (10 -2-10 -1 m 2 s -3). In an attempt to account for different concentrations and assemblages of mixed plankton, mean bioluminescence levels were normalized by an index of the corresponding flow-stimulated bioluminescence potential. This procedure generally accounted for variability between turbulent flow experiments, but was not effective for laminar flow. In turbulent flow, mean bioluminescence levels increased approximately linearly with wall shear stress. The magnitude of the flash response of individual cells, however, remained nearly constant throughout high laminar and turbulent flow, even as the energetic length scales of the turbulence became less than the size of the organisms of interest. Threshold flow stimuli levels determined in the laboratory were compared with oceanic measurements taken from the literature and with numerical simulations of ship wakes, one of the few highly turbulent flows to be well studied. Several oceanic flow fields are proposed as candidates for bioluminescence flow visualization.

  8. Rapid quantification of live cell receptors using bioluminescence in a flow-based microfluidic device.

    Science.gov (United States)

    Ramji, Ramesh; Cheong, Cheong Fook; Hirata, Hiroaki; Rahman, Abdur Rub Abdur; Lim, Chwee Teck

    2015-02-25

    The number of receptors expressed by cells plays an important role in controlling cell signaling events, thus determining its behaviour, state and fate. Current methods of quantifying receptors on cells are either laborious or do not maintain the cells in their native form. Here, a method integrating highly sensitive bioluminescence, high precision microfluidics and small footprint of lensfree optics is developed to quantify cell surface receptors. This method is safe to use, less laborious, and faster than the conventional radiolabelling and near field scanning methods. It is also more sensitive than fluorescence based assays and is ideal for high throughput screening. In quantifying β(1) adrenergic receptors expressed on the surface of H9c2 cardiomyocytes, this method yields receptor numbers from 3.12 × 10(5) to 9.36 × 10(5) receptors/cell which are comparable with current methods. This can serve as a very good platform for rapid quantification of receptor numbers in ligand/drug binding and receptor characterization studies, which is an important part of pharmaceutical and biological research. PMID:25336403

  9. Firefly Luciferase-Based Sequential Bioluminescence Resonance Energy Transfer (BRET)-Fluorescence Resonance Energy Transfer (FRET) Protease Assays.

    Science.gov (United States)

    Branchini, Bruce

    2016-01-01

    We describe here the preparation of ratiometric luminescent probes that contain two well-separated emission peaks produced by a sequential bioluminescence resonance energy transfer (BRET)-fluorescence resonance energy transfer (FRET) process. The probes are single soluble fusion proteins consisting of a thermostable firefly luciferase variant that catalyzes yellow-green (560 nm maximum) bioluminescence and a red fluorescent protein covalently labeled with a near-Infrared fluorescent dye. The two proteins are connected by a decapeptide containing a protease recognition site specific for factor Xa, thrombin, or caspase 3. The rates of protease cleavage of the fusion protein substrates were monitored by recording emission spectra and plotting the change in peak ratios over time. Detection limits of 0.41 nM for caspase 3, 1.0 nM for thrombin, and 58 nM for factor Xa were realized with a scanning fluorometer. This method successfully employs an efficient sequential BRET-FRET energy transfer process based on firefly luciferase bioluminescence to assay physiologically important protease activities and should be generally applicable to the measurement of any endoprotease lacking accessible cysteine residues.

  10. Firefly Luciferase-Based Sequential Bioluminescence Resonance Energy Transfer (BRET)-Fluorescence Resonance Energy Transfer (FRET) Protease Assays.

    Science.gov (United States)

    Branchini, Bruce

    2016-01-01

    We describe here the preparation of ratiometric luminescent probes that contain two well-separated emission peaks produced by a sequential bioluminescence resonance energy transfer (BRET)-fluorescence resonance energy transfer (FRET) process. The probes are single soluble fusion proteins consisting of a thermostable firefly luciferase variant that catalyzes yellow-green (560 nm maximum) bioluminescence and a red fluorescent protein covalently labeled with a near-Infrared fluorescent dye. The two proteins are connected by a decapeptide containing a protease recognition site specific for factor Xa, thrombin, or caspase 3. The rates of protease cleavage of the fusion protein substrates were monitored by recording emission spectra and plotting the change in peak ratios over time. Detection limits of 0.41 nM for caspase 3, 1.0 nM for thrombin, and 58 nM for factor Xa were realized with a scanning fluorometer. This method successfully employs an efficient sequential BRET-FRET energy transfer process based on firefly luciferase bioluminescence to assay physiologically important protease activities and should be generally applicable to the measurement of any endoprotease lacking accessible cysteine residues. PMID:27424898

  11. 基于多角度光学投影表面重建的三维自发荧光光源定位算法%A 3D Location Method of Bioluminescence Light Source Based on Multi-view Pro jection Surface Reconstruction

    Institute of Scientific and Technical Information of China (English)

    宁楠楠; 刘侠; 邓可欣; 吴萍; 王坤; 田捷

    2014-01-01

    In bioluminescent tomography imaging (BLT), dual-modality fusion (optical modality and structural modal-ity) can make full use of high accuracy 3D geometrical structures provided by structural modality reconstruct 3D surface light flux distribution and bioluminescence inner light source reconstruction. However, compared with the all-optical modality, dual-modality fusion has the problems of complicated fusion system, high cost compared with all-optical sys-tem, multifarious and exhaustive date processing, and ionizing radiation (for example, CT). Therefore, the 3D location method of bioluminescence light source based on pure optical 3D geometrical structures has significance for BLT. In this paper, we present a 3D location method of bioluminescence light source based on multi-view projection surface recon-struction, and an all-optical bioluminescence tomography system (AOBTS) is developed for this method. The method consists of 3D surface reconstruction based on multi-view optical pro jection, multi-view luminescent seamless integration, calibration and quantification of the surface light flux and internal bioluminescence reconstruction. An in-vivo BALB/C mouse with an implanted luminescent light source are used to evaluate the performance of the new method. Compared with the conventional optical methods, the new method improves not only the 3D surface reconstruction method but also the multi-view luminescent seamless integration. It has realized 3D real mouse bioluminescence light source localization, and the preliminary test proves its potential application in clinical trial.%在自发荧光断层成像(Bioluminescent tomography imaging, BLT)中,双模态融合(光学模态与结构模态)可充分利用结构模态提供的高精度3D 几何结构,重建三维表面荧光光通量分布,进而实现小动物内部荧光光源定位。然而,与纯光学模态相比,双模态融合存在采集系统复杂、成本高、数据处理繁琐及存在电离辐

  12. A 3D Location Method of Bioluminescence Light Source Based on Multi-view Pro jection Surface Reconstruction%基于多角度光学投影表面重建的三维自发荧光光源定位算法

    Institute of Scientific and Technical Information of China (English)

    宁楠楠; 刘侠; 邓可欣; 吴萍; 王坤; 田捷

    2014-01-01

    在自发荧光断层成像(Bioluminescent tomography imaging, BLT)中,双模态融合(光学模态与结构模态)可充分利用结构模态提供的高精度3D 几何结构,重建三维表面荧光光通量分布,进而实现小动物内部荧光光源定位。然而,与纯光学模态相比,双模态融合存在采集系统复杂、成本高、数据处理繁琐及存在电离辐射(如CT)等问题。因此,研究基于纯光学3D几何结构的自发荧光光源定位方法对BLT具有重要意义。本文在搭建纯光学自发荧光断层系统(All-optical bioluminescence tomography system, AOBTS)的基础上,提出一种基于多角度光学投影表面重建的三维自发荧光光源定位方法。本方法由基于多角度光学投影的3D表面重建、多角度荧光无缝融合、荧光光通量的量化校正以及自发荧光内部光源重建4部分组成。通过真实小鼠内部植入荧光光源实验表明,与传统纯光学方法相比,本文提出方法不仅改进了3D 表面重建方法,而且增加了多角度荧光无缝融合,可实现真实小鼠的三维自发荧光光源定位,初步实验证明具有小动物预临床实验潜力。%In bioluminescent tomography imaging (BLT), dual-modality fusion (optical modality and structural modal-ity) can make full use of high accuracy 3D geometrical structures provided by structural modality reconstruct 3D surface light flux distribution and bioluminescence inner light source reconstruction. However, compared with the all-optical modality, dual-modality fusion has the problems of complicated fusion system, high cost compared with all-optical sys-tem, multifarious and exhaustive date processing, and ionizing radiation (for example, CT). Therefore, the 3D location method of bioluminescence light source based on pure optical 3D geometrical structures has significance for BLT. In this paper, we present a 3D location method of bioluminescence light source based on multi-view projection surface

  13. Quantum Yield Determination Based on Photon Number Measurement, Protocols for Firefly Bioluminescence Reactions.

    Science.gov (United States)

    Niwa, Kazuki

    2016-01-01

    Quantum yield (QY), which is defined as the probability of photon production by a single bio/chemiluminescence reaction, is an important factor to characterize luminescence light intensity emitted diffusively from the reaction solution mixture. Here, methods to measure number of photons to determine QY according to the techniques of national radiometry standards are described. As an example, experiments using firefly bioluminescence reactions are introduced. PMID:27424895

  14. Quantum Yield Determination Based on Photon Number Measurement, Protocols for Firefly Bioluminescence Reactions.

    Science.gov (United States)

    Niwa, Kazuki

    2016-01-01

    Quantum yield (QY), which is defined as the probability of photon production by a single bio/chemiluminescence reaction, is an important factor to characterize luminescence light intensity emitted diffusively from the reaction solution mixture. Here, methods to measure number of photons to determine QY according to the techniques of national radiometry standards are described. As an example, experiments using firefly bioluminescence reactions are introduced.

  15. Development of bacteriophage-based bioluminescent bioreporters for monitoring of microbial pathogens

    Science.gov (United States)

    Ozen, Aysu; Montgomery, Kacey; Jegier, Pat; Patterson, Stacey; Daumer, Kathleen A.; Ripp, Steven A.; Garland, Jay L.; Sayler, Gary S.

    2004-03-01

    Microorganisms pose numerous problems when present in human occupied enclosed environments. Primary among these are health related hazards, manifested as infectious diseases related to contaminated drinking water, food, or air circulation systems or non-infectious allergy related complications associated with microbial metabolites (sick building syndrome). As a means towards rapid detection of microbial pathogens, we are attempting to harness the specificity of bacterial phage for their host with a modified quorum sensing amplification signal to produce quantifiable bioluminescent (lux) detection on a silicon microluminometer. The bacteriophage itself is metabolically inactive, only achieving replicative capabilities upon infection of its specific host bacterium. Bacteriophage bioluminescent bioreporters contain a genomically inserted luxI component. During an infection event, the phage genes and accompanying luxI construct are taken up by the host bacterium and transcribed, resulting in luxI expression and subsequent activation of a homoserine lactone inducible bioluminescent bioreporter. We constructed a vector carrying the luxI gene under the control of a strong E. coli promoter and cloned it into E. coli. We have shown that it can induce luminescence up to 14,000 counts per second when combined with the bioreporter strain. In their final embodiment, these sensors will be fully independent microelectronic monitors for microbial contamination, requiring only exposure of the biochip to the sample, with on-chip signal processing downloaded directly to the local area network of the environmental control system.

  16. Bioluminescence-Based Tumor Quantification Method for Monitoring Tumor Progression and Treatment Effects in Mouse Lymphoma Models.

    Science.gov (United States)

    Cosette, Jeremie; Ben Abdelwahed, Rym; Donnou-Triffault, Sabrina; Sautès-Fridman, Catherine; Flaud, Patrice; Fisson, Sylvain

    2016-01-01

    Although bioluminescence imaging (BLI) shows promise for monitoring tumor burden in animal models of cancer, these analyses remain mostly qualitative. Here we describe a method for bioluminescence imaging to obtain a semi-quantitative analysis of tumor burden and treatment response. This method is based on the calculation of a luminoscore, a value that allows comparisons of two animals from the same or different experiments. Current BLI instruments enable the calculation of this luminoscore, which relies mainly on the acquisition conditions (back and front acquisitions) and the drawing of the region of interest (manual markup around the mouse). Using two previously described mouse lymphoma models based on cell engraftment, we show that the luminoscore method can serve as a noninvasive way to verify successful tumor cell inoculation, monitor tumor burden, and evaluate the effects of in situ cancer treatment (CpG-DNA). Finally, we show that this method suits different experimental designs. We suggest that this method be used for early estimates of treatment response in preclinical small-animal studies. PMID:27501019

  17. Bioluminescence-Based Tumor Quantification Method for Monitoring Tumor Progression and Treatment Effects in Mouse Lymphoma Models.

    Science.gov (United States)

    Cosette, Jeremie; Ben Abdelwahed, Rym; Donnou-Triffault, Sabrina; Sautès-Fridman, Catherine; Flaud, Patrice; Fisson, Sylvain

    2016-07-07

    Although bioluminescence imaging (BLI) shows promise for monitoring tumor burden in animal models of cancer, these analyses remain mostly qualitative. Here we describe a method for bioluminescence imaging to obtain a semi-quantitative analysis of tumor burden and treatment response. This method is based on the calculation of a luminoscore, a value that allows comparisons of two animals from the same or different experiments. Current BLI instruments enable the calculation of this luminoscore, which relies mainly on the acquisition conditions (back and front acquisitions) and the drawing of the region of interest (manual markup around the mouse). Using two previously described mouse lymphoma models based on cell engraftment, we show that the luminoscore method can serve as a noninvasive way to verify successful tumor cell inoculation, monitor tumor burden, and evaluate the effects of in situ cancer treatment (CpG-DNA). Finally, we show that this method suits different experimental designs. We suggest that this method be used for early estimates of treatment response in preclinical small-animal studies.

  18. Development of a Filtration-Based Bioluminescence Assay for Detection of Microorganisms in Tea Beverages.

    Science.gov (United States)

    Shinozaki, Yohei; Igarashi, Toshinori; Harada, Yasuhiro

    2016-03-01

    The market for tea drinks as healthy beverages has been steadily expanding, and ready-to-drink beverages in polyethylene terephthalate bottles have been popular. To more rapidly and accurately test tea beverages bottled in polyethylene terephthalate for microbial contamination, a newly developed filtration device and a washing method with a commercial bioluminescence assay were combined to detect low numbers of bacterial spores, fungal conidia, and ascospores. Washing buffers were formulated with nonionic detergents from the Tween series. Commercially available tea beverages were used to evaluate the filtration capacity of the filtration device, the effect of washing buffers, and the performance of the assay. The assay was tested with serially diluted suspensions of colonies of two bacterial strains, spores of three Bacillus strains, conidia of five fungal strains, and ascospores of four fungal strains. The filtration device enabled filtration of a large sample volume (100 to 500 ml), and the washing buffer significantly decreased the background bioluminescence intensity of tea samples when compared with the no-washing method. Low numbers (1 to 10 CFU/100 ml) of the tested strains of bacteria were detected within 8 to 18 h of cultivation, and fungi were detected within 24 to 48 h. Furthermore, a whole bottle (500 ml) of mixed tea was filtered through the filtration device and microbes were detected. This method could be used for quality control of bottled beverages without preincubation. PMID:26939661

  19. In Vivo Functional Brain Imaging Approach Based on Bioluminescent Calcium Indicator GFP-aequorin.

    Science.gov (United States)

    Lark, Arianna R; Kitamoto, Toshihiro; Martin, Jean-René

    2016-01-08

    Functional in vivo imaging has become a powerful approach to study the function and physiology of brain cells and structures of interest. Recently a new method of Ca(2+)-imaging using the bioluminescent reporter GFP-aequorin (GA) has been developed. This new technique relies on the fusion of the GFP and aequorin genes, producing a molecule capable of binding calcium and - with the addition of its cofactor coelenterazine - emitting bright light that can be monitored through a photon collector. Transgenic lines carrying the GFP-aequorin gene have been generated for both mice and Drosophila. In Drosophila, the GFP-aequorin gene has been placed under the control of the GAL4/UAS binary expression system allowing for targeted expression and imaging within the brain. This method has subsequently been shown to be capable of detecting both inward Ca(2+)-transients and Ca(2+)-released from inner stores. Most importantly it allows for a greater duration in continuous recording, imaging at greater depths within the brain, and recording at high temporal resolutions (up to 8.3 msec). Here we present the basic method for using bioluminescent imaging to record and analyze Ca(2+)-activity within the mushroom bodies, a structure central to learning and memory in the fly brain.

  20. Lighting up bioluminescence with coelenterazine: strategies and applications.

    Science.gov (United States)

    Jiang, Tianyu; Du, Lupei; Li, Minyong

    2016-04-01

    Bioluminescence-based techniques, such as bioluminescence imaging, BRET and dual-luciferase reporter assay systems, have been widely used to examine a myriad of biological processes. Coelenterazine (CTZ), a luciferin or light-producing compound found in bioluminescent organisms, has sparked great curiosity and interest in searching for analogues with improved photochemical properties. This review summarizes the current development of coelenterazine analogues, their bioluminescence properties, and the rational design of caged coelenterazine towards biotargets, as well as their applications in bioassays. It should be emphasized that the design of caged luciferins can provide valuable insight into detailed molecular processes in organisms and will be a trend in the development of bioluminescent molecules.

  1. Analysis of genetically modified organisms by pyrosequencing on a portable photodiode-based bioluminescence sequencer.

    Science.gov (United States)

    Song, Qinxin; Wei, Guijiang; Zhou, Guohua

    2014-07-01

    A portable bioluminescence analyser for detecting the DNA sequence of genetically modified organisms (GMOs) was developed by using a photodiode (PD) array. Pyrosequencing on eight genes (zSSIIb, Bt11 and Bt176 gene of genetically modified maize; Lectin, 35S-CTP4, CP4EPSPS, CaMV35S promoter and NOS terminator of the genetically modified Roundup ready soya) was successfully detected with this instrument. The corresponding limit of detection (LOD) was 0.01% with 35 PCR cycles. The maize and soya available from three different provenances in China were detected. The results indicate that pyrosequencing using the small size of the detector is a simple, inexpensive, and reliable way in a farm/field test of GMO analysis. PMID:24518318

  2. Analysis of genetically modified organisms by pyrosequencing on a portable photodiode-based bioluminescence sequencer.

    Science.gov (United States)

    Song, Qinxin; Wei, Guijiang; Zhou, Guohua

    2014-07-01

    A portable bioluminescence analyser for detecting the DNA sequence of genetically modified organisms (GMOs) was developed by using a photodiode (PD) array. Pyrosequencing on eight genes (zSSIIb, Bt11 and Bt176 gene of genetically modified maize; Lectin, 35S-CTP4, CP4EPSPS, CaMV35S promoter and NOS terminator of the genetically modified Roundup ready soya) was successfully detected with this instrument. The corresponding limit of detection (LOD) was 0.01% with 35 PCR cycles. The maize and soya available from three different provenances in China were detected. The results indicate that pyrosequencing using the small size of the detector is a simple, inexpensive, and reliable way in a farm/field test of GMO analysis.

  3. Robust image modeling technique with a bioluminescence image segmentation application

    Science.gov (United States)

    Zhong, Jianghong; Wang, Ruiping; Tian, Jie

    2009-02-01

    A robust pattern classifier algorithm for the variable symmetric plane model, where the driving noise is a mixture of a Gaussian and an outlier process, is developed. The veracity and high-speed performance of the pattern recognition algorithm is proved. Bioluminescence tomography (BLT) has recently gained wide acceptance in the field of in vivo small animal molecular imaging. So that it is very important for BLT to how to acquire the highprecision region of interest in a bioluminescence image (BLI) in order to decrease loss of the customers because of inaccuracy in quantitative analysis. An algorithm in the mode is developed to improve operation speed, which estimates parameters and original image intensity simultaneously from the noise corrupted image derived from the BLT optical hardware system. The focus pixel value is obtained from the symmetric plane according to a more realistic assumption for the noise sequence in the restored image. The size of neighborhood is adaptive and small. What's more, the classifier function is base on the statistic features. If the qualifications for the classifier are satisfied, the focus pixel intensity is setup as the largest value in the neighborhood.Otherwise, it will be zeros.Finally,pseudo-color is added up to the result of the bioluminescence segmented image. The whole process has been implemented in our 2D BLT optical system platform and the model is proved.

  4. Optimisation of acquisition time in bioluminescence imaging

    Science.gov (United States)

    Taylor, Shelley L.; Mason, Suzannah K. G.; Glinton, Sophie; Cobbold, Mark; Styles, Iain B.; Dehghani, Hamid

    2015-03-01

    Decreasing the acquisition time in bioluminescence imaging (BLI) and bioluminescence tomography (BLT) will enable animals to be imaged within the window of stable emission of the bioluminescent source, a higher imaging throughput and minimisation of the time which an animal is anaesthetised. This work investigates, through simulation using a heterogeneous mouse model, two methods of decreasing acquisition time: 1. Imaging at fewer wavelengths (a reduction from five to three); and 2. Increasing the bandwidth of filters used for imaging. The results indicate that both methods are viable ways of decreasing the acquisition time without a loss in quantitative accuracy. Importantly, when choosing imaging wavelengths, the spectral attenuation of tissue and emission spectrum of the source must be considered, in order to choose wavelengths at which a high signal can be achieved. Additionally, when increasing the bandwidth of the filters used for imaging, the bandwidth must be accounted for in the reconstruction algorithm.

  5. Combining fluorescence and bioluminescence microscopy.

    Science.gov (United States)

    Goda, Kazuhito; Hatta-Ohashi, Yoko; Akiyoshi, Ryutaro; Sugiyama, Takashi; Sakai, Ikuko; Takahashi, Takeo; Suzuki, Hirobumi

    2015-08-01

    Bioluminescence microscopy has revealed that gene expression in individual cells can respond differently to the same stimulus. To understand this phenomenon, it is important to sequentially observe the series of events from cellular signal transduction to gene expression regulated by specific transcription factors derived from signaling cascades in individual cells. However, these processes have been separately analyzed with fluorescence and bioluminescence microscopy. Furthermore, in culture medium, the background fluorescence of luciferin-a substrate of luciferase in promoter assays of gene expression in cultured cells-confounds the simultaneous observation of fluorescence and bioluminescence. Therefore, we optimized conditions for optical filter sets based on spectral properties and the luciferin concentration based on cell permeability for fluorescence observation combined with bioluminescence microscopy. An excitation and emission filter set (492-506 nm and 524-578 nm) was suitable for green fluorescent protein and yellow fluorescent protein imaging of cells, and >100 μM luciferin was acceptable in culture medium based on kinetic constants and the estimated intracellular concentration. Using these parameters, we present an example of sequential fluorescence and bioluminescence microscopic observation of signal transduction (translocation of protein kinase C alpha from the cytoplasm to the plasma membrane) coupled with activation of gene expression by nuclear factor of kappa light polypeptide B in individual cells and show that the gene expression response is not completely concordant with upstream signaling following stimulation with phorbol-12-myristate-13-acetate. Our technique is a powerful imaging tool for analysis of heterogeneous gene expression together with upstream signaling in live single cells.

  6. Tomographic bioluminescence imaging by use of a combined optical-PET (OPET) system: a computer simulation feasibility study

    International Nuclear Information System (INIS)

    The feasibility and limits in performing tomographic bioluminescence imaging with a combined optical-PET (OPET) system were explored by simulating its image formation process. A micro-MRI based virtual mouse phantom was assigned appropriate tissue optical properties to each of its segmented internal organs at wavelengths spanning the emission spectrum of the firefly luciferase at 37 deg. C. The TOAST finite-element code was employed to simulate the diffuse transport of photons emitted from bioluminescence sources in the mouse. OPET measurements were simulated for single-point, two-point and distributed bioluminescence sources located in different organs such as the liver, the kidneys and the gut. An expectation maximization code was employed to recover the intensity and location of these simulated sources. It was found that spectrally resolved measurements were necessary in order to perform tomographic bioluminescence imaging. The true location of emission sources could be recovered if the mouse background optical properties were known a priori. The assumption of a homogeneous optical property background proved inadequate for describing photon transport in optically heterogeneous tissues and led to inaccurate source localization in the reconstructed images. The simulation results pointed out specific methodological challenges that need to be addressed before a practical implementation of OPET-based bioluminescence tomography is achieved

  7. Grating-based tomography of human tissues

    Science.gov (United States)

    Müller, Bert; Schulz, Georg; Mehlin, Andrea; Herzen, Julia; Lang, Sabrina; Holme, Margaret; Zanette, Irene; Hieber, Simone; Deyhle, Hans; Beckmann, Felix; Pfeiffer, Franz; Weitkamp, Timm

    2012-07-01

    The development of therapies to improve our health requires a detailed knowledge on the anatomy of soft tissues from the human body down to the cellular level. Grating-based phase contrast micro computed tomography using synchrotron radiation provides a sensitivity, which allows visualizing micrometer size anatomical features in soft tissue without applying any contrast agent. We show phase contrast tomography data of human brain, tumor vessels and constricted arteries from the beamline ID 19 (ESRF) and urethral tissue from the beamline W2 (HASYLAB/DESY) with micrometer resolution. Here, we demonstrate that anatomical features can be identified within brain tissue as well known from histology. Using human urethral tissue, the application of two photon energies is compared. Tumor vessels thicker than 20 μm can be perfectly segmented. The morphology of coronary arteries can be better extracted in formalin than after paraffin embedding.

  8. Global DNA Methylation Detection System Using MBD-Fused Luciferase Based on Bioluminescence Resonance Energy Transfer Assay.

    Science.gov (United States)

    Yoshida, Wataru; Baba, Yuji; Karube, Isao

    2016-09-20

    DNA methylation plays an important role in the regulation of gene expression. In normal cells, transposable elements that constitute approximately 45% of the human genome are highly methylated to silence their expression. In cancer cells, transposable elements are hypomethylated; therefore, global DNA methylation level is considered as a biomarker for cancer diagnostics. In this study, a homogeneous assay for measuring global DNA methylation level based on bioluminescence resonance energy transfer (BRET) was developed using methyl-CpG binding domain (MBD)-fused luciferase. In this assay, the MBD-luciferase recognizes methylated CpG, thus, BRET between the luciferase and fluorescent DNA intercalating dye is detected. We demonstrated that the BRET signal depended on the DNA methylation level of the target DNA. Moreover, the BRET signal was correlated with the LINE1 DNA methylation level on human genomic DNA, as determined by the bisulfite method. These results indicate that the global DNA methylation level of human genomic DNA could be detected simply by measuring the BRET signal. PMID:27541340

  9. BRET: NanoLuc-Based Bioluminescence Resonance Energy Transfer Platform to Monitor Protein-Protein Interactions in Live Cells.

    Science.gov (United States)

    Mo, Xiu-Lei; Fu, Haian

    2016-01-01

    Bioluminescence resonance energy transfer (BRET) is a prominent biophysical technology for monitoring molecular interactions, and has been widely used to study protein-protein interactions (PPI) in live cells. This technology requires proteins of interest to be associated with an energy donor (i.e., luciferase) and an acceptor (e.g., fluorescent protein) molecule. Upon interaction of the proteins of interest, the donor and acceptor will be brought into close proximity and energy transfer of chemical reaction-induced luminescence to its corresponding acceptor will result in an increased emission at an acceptor-defined wavelength, generating the BRET signal. We leverage the advantages of the superior optical properties of the NanoLuc(®) luciferase (NLuc) as a BRET donor coupled with Venus, a yellow fluorescent protein, as acceptor. We term this NLuc-based BRET platform "BRET(n)". BRET(n) has been demonstrated to have significantly improved assay performance, compared to previous BRET technologies, in terms of sensitivity and scalability. This chapter describes a step-by-step practical protocol for developing a BRET(n) assay in a multi-well plate format to detect PPIs in live mammalian cells.

  10. Glu311 and Arg337 Stabilize a Closed Active-site Conformation and Provide a Critical Catalytic Base and Countercation for Green Bioluminescence in Beetle Luciferases.

    Science.gov (United States)

    Viviani, V R; Simões, A; Bevilaqua, V R; Gabriel, G V M; Arnoldi, F G C; Hirano, T

    2016-08-30

    Beetle luciferases elicit the emission of different bioluminescence colors from green to red. Whereas firefly luciferases emit yellow-green light and are pH-sensitive, undergoing a typical red-shift at acidic pH and higher temperatures and in the presence of divalent heavy metals, click beetle and railroadworm luciferases emit a wider range of colors from green to red but are pH-independent. Despite many decades of study, the structural determinants and mechanisms of bioluminescence colors and pH sensitivity remain enigmatic. Here, through modeling studies, site-directed mutagenesis, and spectral and kinetic studies using recombinant luciferases from the three main families of bioluminescent beetles that emit different colors of light (Macrolampis sp2 firefly, Phrixotrix hirtus railroadworm, and Pyrearinus termitilluminans click beetle), we investigated the role of E311 and R337 in bioluminescence color determination. All mutations of these residues in firefly luciferase produced red mutants, indicating that the preservation of opposite charges and the lengths of the side chains of E311 and R337 are essential for keeping a salt bridge that stabilizes a closed hydrophobic conformation favorable for green light emission. Kinetic studies indicate that residue R337 is important for binding luciferin and creating a positively charged environment around excited oxyluciferin phenolate. In Pyrearinus green-emitting luciferase, the R334A mutation causes a 27 nm red-shift, whereas in Phrixotrix red-emitting luciferase, the L334R mutation causes a blue-shift that is no longer affected by guanidine. These results provide compelling evidence that the presence of arginine at position 334 is essential for blue-shifting the emission spectra of most beetle luciferases. Therefore, residues E311 and R337 play both structural and catalytic roles in bioluminescence color determination, by stabilizing a closed hydrophobic conformation favorable for green light emission, and also

  11. 基于受激发光实验的生物光尾流特性%Characteristics of bioluminescent wake based on stimulated luminescence laboratory experiments

    Institute of Scientific and Technical Information of China (English)

    曹静; 王江安; 何友; 吴荣华

    2011-01-01

    Abstract: Based on the relative characteristics of stimulated bioluminescence and hydrodynamic flow, the experimental plat-form of stimulated bioluminescence in Couette flow was built. The hydrodynamic elements stimulated bioluminescence were analy-sised. The threshold of shear stress for stimulated bioluminescence of Lingulodinium polyedrum is 0. 1 N/m2. And biolumines-cence emission is the function of shear stress and increases with it when the shear stress exceeds the threshold. The shear stress distributions of submarine were simulated by FLUENT software. The results of calculation illustrate that the shear stress decrea-ses with the increased length of wake of submarine and it can be decreased as the oscillation of sine wave in the near area. The shear stress of wake decreases rapidly and widely with the higher speed of submarine, when the speed of submarine is above 4. 1 m/s, the shear stress of wake in 2 000 m length is still over the threshold.%基于生物受激发光与流场机械刺激间的相关性,构建了库埃特流场刺激下的生物受激发光实验平台,分析了影响生物发光的水动力因素剪应力.实验结果显示:引起多边膝沟藻受激发光的剪应力阈值为0.1 N/m2;当流场中的剪应力大于发光阈值后,生物发光强度随着剪应力的增大而增强.采用FLUENT软件模拟计算了不同航速下某潜艇尾流场中的剪应力,计算结果表明:剪应力随着尾流长度的增加而减小,在近场区域剪应力出现了类似正弦波振荡的减小,且航速越大减幅越大,减速越快;当潜艇航速大于4.1 m/s航行时,2 000 m处尾流的剪应力仍然大于引起生物发光的剪应力阈值.

  12. Glu311 and Arg337 Stabilize a Closed Active-site Conformation and Provide a Critical Catalytic Base and Countercation for Green Bioluminescence in Beetle Luciferases.

    Science.gov (United States)

    Viviani, V R; Simões, A; Bevilaqua, V R; Gabriel, G V M; Arnoldi, F G C; Hirano, T

    2016-08-30

    Beetle luciferases elicit the emission of different bioluminescence colors from green to red. Whereas firefly luciferases emit yellow-green light and are pH-sensitive, undergoing a typical red-shift at acidic pH and higher temperatures and in the presence of divalent heavy metals, click beetle and railroadworm luciferases emit a wider range of colors from green to red but are pH-independent. Despite many decades of study, the structural determinants and mechanisms of bioluminescence colors and pH sensitivity remain enigmatic. Here, through modeling studies, site-directed mutagenesis, and spectral and kinetic studies using recombinant luciferases from the three main families of bioluminescent beetles that emit different colors of light (Macrolampis sp2 firefly, Phrixotrix hirtus railroadworm, and Pyrearinus termitilluminans click beetle), we investigated the role of E311 and R337 in bioluminescence color determination. All mutations of these residues in firefly luciferase produced red mutants, indicating that the preservation of opposite charges and the lengths of the side chains of E311 and R337 are essential for keeping a salt bridge that stabilizes a closed hydrophobic conformation favorable for green light emission. Kinetic studies indicate that residue R337 is important for binding luciferin and creating a positively charged environment around excited oxyluciferin phenolate. In Pyrearinus green-emitting luciferase, the R334A mutation causes a 27 nm red-shift, whereas in Phrixotrix red-emitting luciferase, the L334R mutation causes a blue-shift that is no longer affected by guanidine. These results provide compelling evidence that the presence of arginine at position 334 is essential for blue-shifting the emission spectra of most beetle luciferases. Therefore, residues E311 and R337 play both structural and catalytic roles in bioluminescence color determination, by stabilizing a closed hydrophobic conformation favorable for green light emission, and also

  13. Cellular bioluminescence imaging.

    Science.gov (United States)

    Welsh, David K; Noguchi, Takako

    2012-08-01

    Bioluminescence imaging of live cells has recently been recognized as an important alternative to fluorescence imaging. Fluorescent probes are much brighter than bioluminescent probes (luciferase enzymes) and, therefore, provide much better spatial and temporal resolution and much better contrast for delineating cell structure. However, with bioluminescence imaging there is virtually no background or toxicity. As a result, bioluminescence can be superior to fluorescence for detecting and quantifying molecules and their interactions in living cells, particularly in long-term studies. Structurally diverse luciferases from beetle and marine species have been used for a wide variety of applications, including tracking cells in vivo, detecting protein-protein interactions, measuring levels of calcium and other signaling molecules, detecting protease activity, and reporting circadian clock gene expression. Such applications can be optimized by the use of brighter and variously colored luciferases, brighter microscope optics, and ultrasensitive, low-noise cameras. This article presents a review of how bioluminescence differs from fluorescence, its applications to cellular imaging, and available probes, optics, and detectors. It also gives practical suggestions for optimal bioluminescence imaging of single cells.

  14. U-SPECT-BioFluo: an integrated radionuclide, bioluminescence, and fluorescence imaging platform

    NARCIS (Netherlands)

    Van Oosterom, M.N.; Kreuger, R.; Buckle, T.; Mahn, W.A.; Bunschoten, A.; Josephson, L.; Van Leeuwen, F.W.B.; Beekman, F.J.

    2014-01-01

    Background: In vivo bioluminescence, fluorescence, and single-photon emission computed tomography (SPECT) imaging provide complementary information about biological processes. However, to date these signatures are evaluated separately on individual preclinical systems. In this paper, we introduce a

  15. Bioluminescence patterns among North American Armillaria species.

    Science.gov (United States)

    Mihail, Jeanne D

    2015-06-01

    Bioluminescence is widely recognized among white-spored species of Basidiomycota. Most reports of fungal bioluminescence are based upon visual light perception. When instruments such as photomultipliers have been used to measure fungal luminescence, more taxa have been discovered to produce light, albeit at a range of magnitudes. The present studies were undertaken to determine the prevalence of bioluminescence among North American Armillaria species. Consistent, constitutive bioluminescence was detected for the first time for mycelia of Armillaria calvescens, Armillaria cepistipes, Armillaria gemina, Armillaria nabsnona, and Armillaria sinapina and confirmed for mycelia of Armillaria gallica, Armillaria mellea, Armillaria ostoyae, and Armillaria tabescens. Emission spectra of mycelia representing all species had maximum intensity in the range 515-525 nm confirming that emitted light was the result of bioluminescence rather than chemiluminescence. Time series analysis of 1000 consecutive luminescence measurements revealed a highly significant departure from random variation. Mycelial luminescence of eight species exhibited significant, stable shifts in magnitude in response to a series of mechanical disturbance treatments, providing one mechanism for generating observed luminescence variation.

  16. Using bioluminescence imaging in glioma research.

    Science.gov (United States)

    Luwor, Rodney B; Stylli, Stanley S; Kaye, Andrew H

    2015-05-01

    Glioblastoma multiforme (GBM) is the most common malignant brain tumour and has the worst prognosis. Over the last decade, the use of bioluminescence imaging technology has rapidly become widespread to further understand the mechanisms that drive GBM development and progression. Pre-clinical evaluation and optimisation of therapeutic efficacy in GBM research has also utilised this simple non-invasive technology. Here we summarise recent advances made in glioma biology and therapeutic intervention using bioluminescence imaging. This review also describes the current knowledge regarding the use of luciferase-based reporters in examining the role of specific cancer signalling cascades that promote glioma progression.

  17. Bioluminescent bioreporter integrated circuit

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Michael L. (Knoxville, TN); Sayler, Gary S. (Blaine, TN); Paulus, Michael J. (Knoxville, TN)

    2000-01-01

    Disclosed are monolithic bioelectronic devices comprising a bioreporter and an OASIC. These bioluminescent bioreporter integrated circuit are useful in detecting substances such as pollutants, explosives, and heavy-metals residing in inhospitable areas such as groundwater, industrial process vessels, and battlefields. Also disclosed are methods and apparatus for environmental pollutant detection, oil exploration, drug discovery, industrial process control, and hazardous chemical monitoring.

  18. Detection for Viability of Wheat Based on Ultra -Weak Delayed Bioluminescence%基于超弱延迟发光的小麦生活力检测方法研究

    Institute of Scientific and Technical Information of China (English)

    吴才章; 牛群峰; 张兰静

    2015-01-01

    The variation of the ultra -weak delayed bioluminescence under different viability and different test conditions was investigated with zhengmai 9023 as an experimental object.The different viability wheat sample could be obtained by rapid artificial aging,and the characteristics of the delayed bioluminescence from different viability and the influence of temperature on the delayed bioluminescence were studied.The results showed that obvious differences were found in the delayed bioluminescence ability for different viability with the same seeds.There was a negative correlation between the delayed bioluminescence and its viability.In other words,its viability was strengthened as the delayed bi-oluminescence was weakened.The influence of temperature on the delayed bioluminescence was obvious.As the temper-ature rose,the intensity of ultra -weak photon emission decreased gradually.The research demonstrated that it was feasi-ble to detect wheat viability based on the ultra -weak delayed bioluminescence under the strict control of test conditions.%以郑麦9023为试验对象,研究了不同生活力和不同测试条件下小麦样品超弱延迟发光的变化情况。通过人工快速陈化的方法获得不同生活力的小麦样品,对这些小麦样品的延迟发光特性进行系统研究,在此基础上以温度为例研究了测试条件对小麦延迟发光的影响。结果表明,同一品种不同生活力小麦样品的延迟发光能力差异明显,小麦的延迟发光强度与其生活力显著负相关,生活力越强,其延迟发光能力越弱;小麦的延迟发光能力受其自身温度的影响显著,随着温度的升高,其延迟发光能力减弱。本研究发现,利用超弱延迟发光进行小麦生活力检测是可行的,但需要对测试条件进行严格控制。

  19. 基于超弱延迟发光的小麦生活力检测方法研究%Detection for Viability of Wheat Based on Ultra -Weak Delayed Bioluminescence

    Institute of Scientific and Technical Information of China (English)

    吴才章; 牛群峰; 张兰静

    2015-01-01

    以郑麦9023为试验对象,研究了不同生活力和不同测试条件下小麦样品超弱延迟发光的变化情况。通过人工快速陈化的方法获得不同生活力的小麦样品,对这些小麦样品的延迟发光特性进行系统研究,在此基础上以温度为例研究了测试条件对小麦延迟发光的影响。结果表明,同一品种不同生活力小麦样品的延迟发光能力差异明显,小麦的延迟发光强度与其生活力显著负相关,生活力越强,其延迟发光能力越弱;小麦的延迟发光能力受其自身温度的影响显著,随着温度的升高,其延迟发光能力减弱。本研究发现,利用超弱延迟发光进行小麦生活力检测是可行的,但需要对测试条件进行严格控制。%The variation of the ultra -weak delayed bioluminescence under different viability and different test conditions was investigated with zhengmai 9023 as an experimental object.The different viability wheat sample could be obtained by rapid artificial aging,and the characteristics of the delayed bioluminescence from different viability and the influence of temperature on the delayed bioluminescence were studied.The results showed that obvious differences were found in the delayed bioluminescence ability for different viability with the same seeds.There was a negative correlation between the delayed bioluminescence and its viability.In other words,its viability was strengthened as the delayed bi-oluminescence was weakened.The influence of temperature on the delayed bioluminescence was obvious.As the temper-ature rose,the intensity of ultra -weak photon emission decreased gradually.The research demonstrated that it was feasi-ble to detect wheat viability based on the ultra -weak delayed bioluminescence under the strict control of test conditions.

  20. A planar circular detector based on multiple point chemi- or bio-luminescent source within a coaxial cylindrical reactor

    International Nuclear Information System (INIS)

    An analytical method was proposed for calculating radiative fluxes incident on a planar circular detector from a volume multiple point chemi- or bio-luminescent source inside a coaxial cylindrical reactor. The method was designed for a cylindrical reactor when the surface reflections were neglected and when chemi- or bio-luminescence reaches a detector embedded in the same homogeneous optical medium as the point emitters of the volume multiple point source model. The radiative fluxes from arbitrarily distributed point emitters were expressed by one generalized quadruple-integral formula. Then some double- and single-integral formulas were obtained for calculating radiative fluxes from identically radiating point emitters uniformly distributed within the reactor. Selected results were computed and illustrated graphically. The obtained formulas are suitable for optimizing and/or calibrating the considered source-detectors systems (optical radiometers or luminometers) and determining radiative fluxes generated by chemical, biological, and physical processes leading to chemi-, bio-, radio-, and sono-luminescence for example.

  1. Bioluminescence lights the way to food safety

    Science.gov (United States)

    Brovko, Lubov Y.; Griffiths, Mansel W.

    2003-07-01

    The food industry is increasingly adopting food safety and quality management systems that are more proactive and preventive than those used in the past which have tended to rely on end product testing and visual inspection. The regulatory agencies in many countries are promoting one such management tool, Hazard Analysis Critical Control Point (HACCP), as a way to achieve a safer food supply and as a basis for harmonization of trading standards. Verification that the process is safe must involve microbiological testing but the results need not be generated in real-time. Of all the rapid microbiological tests currently available, the only ones that come close to offering real-time results are bioluminescence-based methods. Recent developments in application of bioluminescence for food safety issues are presented in the paper. These include the use of genetically engineered microorganisms with bioluminescent and fluorescent phenotypes as a real time indicator of physiological state and survival of food-borne pathogens in food and food processing environments as well as novel bioluminescent-based methods for rapid detection of pathogens in food and environmental samples. Advantages and pitfalls of the methods are discussed.

  2. Novel fusion for hybrid optical/microcomputed tomography imaging based on natural light surface reconstruction and iterated closest point

    Science.gov (United States)

    Ning, Nannan; Tian, Jie; Liu, Xia; Deng, Kexin; Wu, Ping; Wang, Bo; Wang, Kun; Ma, Xibo

    2014-02-01

    In mathematics, optical molecular imaging including bioluminescence tomography (BLT), fluorescence tomography (FMT) and Cerenkov luminescence tomography (CLT) are concerned with a similar inverse source problem. They all involve the reconstruction of the 3D location of a single/multiple internal luminescent/fluorescent sources based on 3D surface flux distribution. To achieve that, an accurate fusion between 2D luminescent/fluorescent images and 3D structural images that may be acquired form micro-CT, MRI or beam scanning is extremely critical. However, the absence of a universal method that can effectively convert 2D optical information into 3D makes the accurate fusion challengeable. In this study, to improve the fusion accuracy, a new fusion method for dual-modality tomography (luminescence/fluorescence and micro-CT) based on natural light surface reconstruction (NLSR) and iterated closest point (ICP) was presented. It consisted of Octree structure, exact visual hull from marching cubes and ICP. Different from conventional limited projection methods, it is 360° free-space registration, and utilizes more luminescence/fluorescence distribution information from unlimited multi-orientation 2D optical images. A mouse mimicking phantom (one XPM-2 Phantom Light Source, XENOGEN Corporation) and an in-vivo BALB/C mouse with implanted one luminescent light source were used to evaluate the performance of the new fusion method. Compared with conventional fusion methods, the average error of preset markers was improved by 0.3 and 0.2 pixels from the new method, respectively. After running the same 3D internal light source reconstruction algorithm of the BALB/C mouse, the distance error between the actual and reconstructed internal source was decreased by 0.19 mm.

  3. Bubble stimulation efficiency of dinoflagellate bioluminescence.

    Science.gov (United States)

    Deane, Grant B; Stokes, M Dale; Latz, Michael I

    2016-02-01

    Dinoflagellate bioluminescence, a common source of bioluminescence in coastal waters, is stimulated by flow agitation. Although bubbles are anecdotally known to be stimulatory, the process has never been experimentally investigated. This study quantified the flash response of the bioluminescent dinoflagellate Lingulodinium polyedrum to stimulation by bubbles rising through still seawater. Cells were stimulated by isolated bubbles of 0.3-3 mm radii rising at their terminal velocity, and also by bubble clouds containing bubbles of 0.06-10 mm radii for different air flow rates. Stimulation efficiency, the proportion of cells producing a flash within the volume of water swept out by a rising bubble, decreased with decreasing bubble radius for radii less than approximately 1 mm. Bubbles smaller than a critical radius in the range 0.275-0.325 mm did not stimulate a flash response. The fraction of cells stimulated by bubble clouds was proportional to the volume of air in the bubble cloud, with lower stimulation levels observed for clouds with smaller bubbles. An empirical model for bubble cloud stimulation based on the isolated bubble observations successfully reproduced the observed stimulation by bubble clouds for low air flow rates. High air flow rates stimulated more light emission than expected, presumably because of additional fluid shear stress associated with collective buoyancy effects generated by the high air fraction bubble cloud. These results are relevant to bioluminescence stimulation by bubbles in two-phase flows, such as in ship wakes, breaking waves, and sparged bioreactors.

  4. 基于 ATP 发光的细菌污染物检测系统%A DESIGN OF BACTERIA DETECTION SYSTEM BASED ON ATP BIOLUMINESCENCE TECHNOLOGY

    Institute of Scientific and Technical Information of China (English)

    张志杰; 王春兴

    2016-01-01

    作者设计了一种基于三磷酸腺苷(ATP)发光技术的细菌数量快速检测系统。系统运用了自动加样技术在暗室中反应,减少了外界杂光的干扰;并优化以光度校准单元,提高了检测可靠性。采用高测量灵敏度的 H5773-02型光电倍增管(PMT)进行光电转换来检测微弱的荧光信号。测试结果表明荧光强度与 ATP 浓度成线性关系。该系统检测时间短,精度高,在食品、药品安全检测中具有较广泛的应用。%According to the requirements of the current market for detecting the number of bacteria rapidly,a detecting system based on ATP bioluminescence technology is designed. In order to reduce the outside scattering light interference,the reagents are filled automatically into the dark container. The optical calibration unit enhances the reliability of the system. H5773 - 02 type PMT can realize photoelectric conversion. The testing results show that the bioluminescence has a great linear correlation with the ATP concentration. The system can detect0 rapidly and accurately,and has a strong potential in the food and drug safety detection.

  5. In vivo functional calcium imaging of induced or spontaneous activity in the fly brain using a GFP-apoaequorin-based bioluminescent approach.

    Science.gov (United States)

    Minocci, Daiana; Carbognin, Elena; Murmu, Meena Sriti; Martin, Jean-René

    2013-07-01

    Different optical imaging techniques have been developed to study neuronal activity with the goal of deciphering the neural code underlying neurophysiological functions. Because of several constraints inherent in these techniques as well as difficulties interpreting the results, the majority of these studies have been dedicated more to sensory modalities than to the spontaneous activity of the central brain. Recently, a novel bioluminescence approach based on GFP-aequorin (GA) (GFP: Green fluorescent Protein), has been developed, allowing us to functionally record in-vivo neuronal activity. Taking advantage of the particular characteristics of GA, which does not require light excitation, we report that we can record induced and/or the spontaneous Ca(2+)-activity continuously over long periods. Targeting GA to the mushrooms-bodies (MBs), a structure implicated in learning/memory and sleep, we have shown that GA is sensitive enough to detect odor-induced Ca(2+)-activity in Kenyon cells (KCs). It has been possible to reveal two particular peaks of spontaneous activity during overnight recording in the MBs. Other peaks of spontaneous activity have been recorded in flies expressing GA pan-neurally. Similarly, expression in the glial cells has revealed that these cells exhibit a cell-autonomous Ca(2+)-activity. These results demonstrate that bioluminescence imaging is a useful tool for studying Ca(2+)-activity in neuronal and/or glial cells and for functional mapping of the neurophysiological processes in the fly brain. These findings provide a framework for investigating the biological meaning of spontaneous neuronal activity. This article is part of a Special Issue entitled: 12th European Symposium on Calcium.

  6. In vivo functional calcium imaging of induced or spontaneous activity in the fly brain using a GFP-apoaequorin-based bioluminescent approach.

    Science.gov (United States)

    Minocci, Daiana; Carbognin, Elena; Murmu, Meena Sriti; Martin, Jean-René

    2013-07-01

    Different optical imaging techniques have been developed to study neuronal activity with the goal of deciphering the neural code underlying neurophysiological functions. Because of several constraints inherent in these techniques as well as difficulties interpreting the results, the majority of these studies have been dedicated more to sensory modalities than to the spontaneous activity of the central brain. Recently, a novel bioluminescence approach based on GFP-aequorin (GA) (GFP: Green fluorescent Protein), has been developed, allowing us to functionally record in-vivo neuronal activity. Taking advantage of the particular characteristics of GA, which does not require light excitation, we report that we can record induced and/or the spontaneous Ca(2+)-activity continuously over long periods. Targeting GA to the mushrooms-bodies (MBs), a structure implicated in learning/memory and sleep, we have shown that GA is sensitive enough to detect odor-induced Ca(2+)-activity in Kenyon cells (KCs). It has been possible to reveal two particular peaks of spontaneous activity during overnight recording in the MBs. Other peaks of spontaneous activity have been recorded in flies expressing GA pan-neurally. Similarly, expression in the glial cells has revealed that these cells exhibit a cell-autonomous Ca(2+)-activity. These results demonstrate that bioluminescence imaging is a useful tool for studying Ca(2+)-activity in neuronal and/or glial cells and for functional mapping of the neurophysiological processes in the fly brain. These findings provide a framework for investigating the biological meaning of spontaneous neuronal activity. This article is part of a Special Issue entitled: 12th European Symposium on Calcium. PMID:23287020

  7. A DESIGN OF BACTERIA DETECTION SYSTEM BASED ON ATP BIOLUMINESCENCE TECHNOLOGY%基于 ATP 发光的细菌污染物检测系统

    Institute of Scientific and Technical Information of China (English)

    张志杰; 王春兴

    2016-01-01

    作者设计了一种基于三磷酸腺苷(ATP)发光技术的细菌数量快速检测系统。系统运用了自动加样技术在暗室中反应,减少了外界杂光的干扰;并优化以光度校准单元,提高了检测可靠性。采用高测量灵敏度的 H5773-02型光电倍增管(PMT)进行光电转换来检测微弱的荧光信号。测试结果表明荧光强度与 ATP 浓度成线性关系。该系统检测时间短,精度高,在食品、药品安全检测中具有较广泛的应用。%According to the requirements of the current market for detecting the number of bacteria rapidly,a detecting system based on ATP bioluminescence technology is designed. In order to reduce the outside scattering light interference,the reagents are filled automatically into the dark container. The optical calibration unit enhances the reliability of the system. H5773 - 02 type PMT can realize photoelectric conversion. The testing results show that the bioluminescence has a great linear correlation with the ATP concentration. The system can detect0 rapidly and accurately,and has a strong potential in the food and drug safety detection.

  8. BIOLUMINESCENCE IMAGING: PROGRESS AND APPLICATIONS

    OpenAIRE

    Badr, Christian E.; Tannous, Bakhos A

    2011-01-01

    Application of bioluminescence imaging has grown tremendously in the past decade and has significantly contributed to the core conceptual advances in biomedical research. This technology provides valuable means for monitoring of different biological processes for immunology, oncology, virology and neuroscience. In this review, we will discuss current trends in bioluminescence and its application in different fields with emphasis on cancer research.

  9. Real-Time Bioluminescence Imaging of Nitroreductase in Mouse Model.

    Science.gov (United States)

    Feng, Ping; Zhang, Huateng; Deng, Quankun; Liu, Wei; Yang, Linghui; Li, Guobo; Chen, Guo; Du, Lupei; Ke, Bowen; Li, Minyong

    2016-06-01

    Nitroreductase (NTR) is an endogenous reductase overexpressed in hypoxic tumors; however, its precise detection in living cells and animals remains a considerable challenge. Herein, we developed three reaction-based probes and a related bioluminescence assay for the real-time NTR detection. The high sensitivity and selectivity of probe 3, combined with its remarkable potential of bioluminescence imaging, affords a valuable approach for in vivo imaging of NTR in a tumor model mouse. PMID:27197544

  10. Real-Time Bioluminescence Imaging of Nitroreductase in Mouse Model.

    Science.gov (United States)

    Feng, Ping; Zhang, Huateng; Deng, Quankun; Liu, Wei; Yang, Linghui; Li, Guobo; Chen, Guo; Du, Lupei; Ke, Bowen; Li, Minyong

    2016-06-01

    Nitroreductase (NTR) is an endogenous reductase overexpressed in hypoxic tumors; however, its precise detection in living cells and animals remains a considerable challenge. Herein, we developed three reaction-based probes and a related bioluminescence assay for the real-time NTR detection. The high sensitivity and selectivity of probe 3, combined with its remarkable potential of bioluminescence imaging, affords a valuable approach for in vivo imaging of NTR in a tumor model mouse.

  11. Bioluminescent bacteria: lux genes as environmental biosensors

    OpenAIRE

    Nunes-Halldorson Vânia da Silva; Duran Norma Letícia

    2003-01-01

    Bioluminescent bacteria are widespread in natural environments. Over the years, many researchers have been studying the physiology, biochemistry and genetic control of bacterial bioluminescence. These discoveries have revolutionized the area of Environmental Microbiology through the use of luminescent genes as biosensors for environmental studies. This paper will review the chronology of scientific discoveries on bacterial bioluminescence and the current applications of bioluminescence in env...

  12. Bioluminescent Ligand-Receptor Binding Assays for Protein or Peptide Hormones.

    Science.gov (United States)

    Liu, Ya-Li; Guo, Zhan-Yun

    2016-01-01

    Bioluminescence has been widely used in biomedical research due to its high sensitivity, low background, and broad linear range. In recent studies, we applied bioluminescence to ligand-receptor binding assays for some protein or peptide hormones based on a newly developed small monomeric Nanoluciferase (NanoLuc) reporter that has the so far brightest bioluminescence. The conventional ligand-receptor binding assays rely on radioligands that have drawbacks, such as radioactive hazards and short shelf lives. In contrast, the novel bioluminescent binding assays use the NanoLuc-based protein or peptide tracers that are safe, stable, and ultrasensitive. Thus, the novel bioluminescent ligand-receptor binding assay would be applied to more and more protein or peptide hormones for ligand-receptor interaction studies in future. In the present article, we provided detailed protocols for setting up the novel bioluminescent ligand-receptor binding assays using two representative protein hormones as examples. PMID:27424896

  13. Mechanisms of bioluminescence, chemiluminescence and of their regulation. Progress report, one year period through March 1976

    Energy Technology Data Exchange (ETDEWEB)

    Seliger, H H

    1976-01-01

    Progress is reported on a 10-yr study of the production and role of excited states in biological systems and the mechanisms involved in bioluminescence and chemoluminescence. An hypothesis of the origin of bioluminescence is presented that is based on the mixed function oxygenase reaction. Techniques of absolute measurements of light intensities and spectral composition were applied in studies of bioluminescence of marine dinoflagellates and the chemiluminescence of carcinogenic polycyclic aromatic hydrocarbons as the result of enzymatic hydroxylation. (CH)

  14. Optical Microangiography Based on Optical Coherence Tomography

    Science.gov (United States)

    Reif, Roberto; Wang, Ruikang K.

    Proper homeostasis regulation of in vivo biological systems requires microvascular blood perfusion, which is the process of delivering blood into the tissue's capillary beds. Abnormal tissue vascularization has been associated with various diseases such as cancer, diabetes, neurological disorders, wounds, and inflammation. Understanding the changes in the vascular network or microangiography will have an important role in determining the causes and developing potential treatments for these diseases. Optical coherence tomography (OCT) is a noninvasive method for imaging three-dimensional biological tissues with high resolution (~10 µm) and without requiring the use of contrast agents. In this chapter we review several techniques for using OCT to determine blood flow velocities and the vessel morphology (optical microangiography). Different techniques will be discussed with a brief explanation of their limitations. Also, methods for quantifying these images are presented, as well as the depiction of several applications.

  15. Measurement of Bacterial Bioluminescence Intensity and Spectrum: Current Physical Techniques and Principles.

    Science.gov (United States)

    Jia, Kun; Ionescu, Rodica Elena

    2016-01-01

    : Bioluminescence is light production by living organisms, which can be observed in numerous marine creatures and some terrestrial invertebrates. More specifically, bacterial bioluminescence is the "cold light" produced and emitted by bacterial cells, including both wild-type luminescent and genetically engineered bacteria. Because of the lively interplay of synthetic biology, microbiology, toxicology, and biophysics, different configurations of whole-cell biosensors based on bacterial bioluminescence have been designed and are widely used in different fields, such as ecotoxicology, food toxicity, and environmental pollution. This chapter first discusses the background of the bioluminescence phenomenon in terms of optical spectrum. Platforms for bacterial bioluminescence detection using various techniques are then introduced, such as a photomultiplier tube, charge-coupled device (CCD) camera, micro-electro-mechanical systems (MEMS), and complementary metal-oxide-semiconductor (CMOS) based integrated circuit. Furthermore, some typical biochemical methods to optimize the analytical performances of bacterial bioluminescent biosensors/assays are reviewed, followed by a presentation of author's recent work concerning the improved sensitivity of a bioluminescent assay for pesticides. Finally, bacterial bioluminescence as implemented in eukaryotic cells, bioluminescent imaging, and cancer cell therapies is discussed.

  16. Cloning and characterization of new bioluminescent proteins

    Science.gov (United States)

    Szent-Gyorgyi, Christopher; Ballou, Byron T.; Dagnal, Erich; Bryan, Bruce

    1999-07-01

    Over the past two years Prolume has undertaken a comprehensive program to clone luciferases and associated 'green fluorescent proteins' (GFPs) from marine animals that use coelenterazine as the luciferin. To data we have cloned several bioluminescent proteins, including two novel copepod luciferases and two anthozoan GFPs. These four proteins have sequences that differ greatly form previously cloned analogous proteins; the sequence diversity apparently is due to independent evolutionary origins and unusual evolutionary constraints. Thus coelenterazine-based bioluminescent systems may also manifest a variety of useful properties. We discuss form this taxonomic perspective the initial biochemical and spectral characterization of our cloned proteins. Emphasis is placed on the anthozoan luciferase-GFP systems, whose efficient resonance energy transfer has elicited much current interest.

  17. Chemiluminescence and bioluminescence microbe detection

    Science.gov (United States)

    Taylor, R. E.; Chappelle, E.; Picciolo, G. L.; Jeffers, E. L.; Thomas, R. R.

    1978-01-01

    Automated biosensors for online use with NASA Water Monitoring System employs bioluminescence and chemiluminescence techniques to rapidly measure microbe contamination of water samples. System eliminates standard laboratory procedures requiring time duration of 24 hours or longer.

  18. Phage-amplified bioluminescent bioreporters for the detection of foodborne pathogens

    Science.gov (United States)

    Ripp, Steven; Young, Jacque C.; Ozen, Aysu; Jegier, Patricia; Johnson, Courtney; Daumer, Kathleen; Garland, Jay; Sayler, Gary S.

    2004-06-01

    The objective of this investigation is to develop a bioluminescent bioreporter system for the detection and monitoring of pathogenic microbial species. Current detection methodologies typically rely on time-consuming sample pre-enrichment steps to elevate pathogen concentrations to detectable levels or DNA based polymerase chain reaction (PCR) techniques that require extensive user training and expensive instrumentation. Detection utilizing bioluminescent bioreporter organisms, however, can provide a simple and rapid means of monitoring foodborne pathogens. Bioluminescent bioreporters are engineered to produce light in response to specific environmental inducers. The light signal is then measured with photodetector devices to generate a quantitative assessment of inducer concentration. The immediate goal of this research effort is to integrate key quorum sensing signal transduction elements into pathogen specific bacteriophages. Upon infection of a unique pathogenic species by the bacteriophages, quorum sensing signals will be generated that will subsequently stimulate bioluminescence in neighboring bioluminescent bioreporter cells. Utilizing both bacteriophages and bioluminescent bioreporters, we realize exceptional pathogen specificity while attaining enhanced bioluminescence production. This integrative approach will lead to rapid pathogen identification without requisite sample pre-enrichment. Additionally, since the bioluminescent response is completely intrinsic to the bioreporter organism, no user interventions are required for generating light signals; the protocol requires only addition of the food sample with the bacteriophage/bioluminescent bioreporter system. Measurement of light responses can be achieved using high-throughput microtiter plate readers, hand-held photomultiplier units, or microchip luminometers.

  19. Scan-plane truncation in diffraction tomography-based imaging

    DEFF Research Database (Denmark)

    Rubæk, Tonny; Meincke, Peter

    2005-01-01

    Three approaches for truncating the scan plane in diffraction tomography-based imaging are suggested and compared. The first and second approaches involve multiplication of a window to the scattered field before evaluating the spatial Fourier transform. The third method relies on an asymptotic end...

  20. Computed tomography of the human developing anterior skull base

    NARCIS (Netherlands)

    J. van Loosen (J.); A.I.J. Klooswijk (A. I J); D. van Velzen (D.); C.D.A. Verwoerd (Carel)

    1990-01-01

    markdownabstractAbstract The ossification of the anterior skull base, especially the lamina cribrosa, has been studied by computed tomography and histopathology. Sixteen human fetuses, (referred to our laboratory for pathological examination after spontaneous abortion between 18 and 32 weeks of ge

  1. Bioluminescence tracking of alginate micro-encapsulated cell transplants.

    Science.gov (United States)

    Tiernan, Aubrey R; Sambanis, Athanassios

    2014-07-22

    Cell-based therapies to treat loss-of-function hormonal disorders such as diabetes and Parkinson's disease are routinely coupled with encapsulation strategies, but an understanding of when and why grafts fail in vivo is lacking. Consequently, investigators cannot clearly define the key factors that influence graft success. Although bioluminescence is a popular method to track the survival of free cells transplanted in preclinical models, little is known of the ability to use bioluminescence for real-time tracking of microencapsulated cells. Furthermore, the impact that dynamic imaging distances may have, due to freely-floating microcapsules in vivo, on cell survival monitoring is unknown. This work addresses these questions by applying bioluminescence to a pancreatic substitute based on microencapsulated cells. Recombinant insulin-secreting cells were transduced with a luciferase lentivirus and microencapsulated in Ba(2+) crosslinked alginate for in vitro and in vivo studies. In vitro quantitative bioluminescence monitoring was possible and viable microencapsulated cells were followed in real time under both normoxic and anoxic conditions. Although in vivo dispersion of freely-floating microcapsules in the peritoneal cavity limited the analysis to a qualitative bioluminescence evaluation, signals consistently four orders of magnitude above background were clear indicators of temporal cell survival. Strong agreement between in vivo and in vitro cell proliferation over time was discovered by making direct bioluminescence comparisons between explanted microcapsules and parallel in vitro cultures. Broader application of this bioluminescence approach to retrievable transplants, in supplement to currently used end-point physiological tests, could improve understanding and accelerate development of cell-based therapies for critical clinical applications. Copyright © 2014 John Wiley & Sons, Ltd.

  2. Electron tomography based on a total variation minimization reconstruction technique

    Energy Technology Data Exchange (ETDEWEB)

    Goris, B., E-mail: bart.goris@ua.ac.be [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Van den Broek, W. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Batenburg, K.J. [Centrum Wiskunde and Informatica, Science Park 123, NL-1098XG Amsterdam (Netherlands); Vision Lab, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Heidari Mezerji, H.; Bals, S. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2012-02-15

    The 3D reconstruction of a tilt series for electron tomography is mostly carried out using the weighted backprojection (WBP) algorithm or using one of the iterative algorithms such as the simultaneous iterative reconstruction technique (SIRT). However, it is known that these reconstruction algorithms cannot compensate for the missing wedge. Here, we apply a new reconstruction algorithm for electron tomography, which is based on compressive sensing. This is a field in image processing specialized in finding a sparse solution or a solution with a sparse gradient to a set of ill-posed linear equations. Therefore, it can be applied to electron tomography where the reconstructed objects often have a sparse gradient at the nanoscale. Using a combination of different simulated and experimental datasets, it is shown that missing wedge artefacts are reduced in the final reconstruction. Moreover, it seems that the reconstructed datasets have a higher fidelity and are easier to segment in comparison to reconstructions obtained by more conventional iterative algorithms. -- Highlights: Black-Right-Pointing-Pointer A reconstruction algorithm for electron tomography is investigated based on total variation minimization. Black-Right-Pointing-Pointer Missing wedge artefacts are reduced by this algorithm. Black-Right-Pointing-Pointer The reconstruction is easier to segment. Black-Right-Pointing-Pointer More reliable quantitative information can be obtained.

  3. Travel-time-based thermal tracer tomography

    Science.gov (United States)

    Somogyvári, Márk; Bayer, Peter; Brauchler, Ralf

    2016-05-01

    Active thermal tracer testing is a technique to get information about the flow and transport properties of an aquifer. In this paper we propose an innovative methodology using active thermal tracers in a tomographic setup to reconstruct cross-well hydraulic conductivity profiles. This is facilitated by assuming that the propagation of the injected thermal tracer is mainly controlled by advection. To reduce the effects of density and viscosity changes and thermal diffusion, early-time diagnostics are used and specific travel times of the tracer breakthrough curves are extracted. These travel times are inverted with an eikonal solver using the staggered grid method to reduce constraints from the pre-defined grid geometry and to improve the resolution. Finally, non-reliable pixels are removed from the derived hydraulic conductivity tomograms. The method is applied to successfully reconstruct cross-well profiles as well as a 3-D block of a high-resolution fluvio-aeolian aquifer analog data set. Sensitivity analysis reveals a negligible role of the injection temperature, but more attention has to be drawn to other technical parameters such as the injection rate. This is investigated in more detail through model-based testing using diverse hydraulic and thermal conditions in order to delineate the feasible range of applications for the new tomographic approach.

  4. Application of optical coherence tomography based microangiography for cerebral imaging

    Science.gov (United States)

    Baran, Utku; Wang, Ruikang K.

    2016-03-01

    Requirements of in vivo rodent brain imaging are hard to satisfy using traditional technologies such as magnetic resonance imaging and two-photon microscopy. Optical coherence tomography (OCT) is an emerging tool that can easily reach at high speeds and provide high resolution volumetric images with a relatively large field of view for rodent brain imaging. Here, we provide the overview of recent developments of functional OCT based imaging techniques for neuroscience applications on rodents. Moreover, a summary of OCT-based microangiography (OMAG) studies for stroke and traumatic brain injury cases on rodents are provided.

  5. Circular polarization observed in bioluminescence

    NARCIS (Netherlands)

    Wijnberg, Hans; Meijer, E.W.; Hummelen, J.C.; Dekkers, H.P.J.M.; Schippers, P.H.; Carlson, A.D.

    1980-01-01

    While investigating circular polarization in luminescence, and having found it in chemiluminescence, we have studied bioluminescence because it is such a widespread and dramatic natural phenomenon. We report here that left and right lanterns of live larvae of the fireflies, Photuris lucicrescens and

  6. Fiber optic based optical coherence tomography (OCT) for dental applications

    Energy Technology Data Exchange (ETDEWEB)

    Everett, M. J., LLNL

    1998-06-02

    We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity We have produced, using this scanning device, in viva cross-sectional images of hard and soft dental tissues in human volunteers Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento-enamel junction, were visible in all the images The dento-enamel junction and the alveolar bone were identifiable in approximately two thirds of the images These images represent, to our knowledge, the first in viva OCT images of human dental tissue.

  7. Electromagnetic tomography (EMT): image reconstruction based on the inverse problem

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Starting from Maxwell's equations for inhomogeneous media, nonlinear integral equations of the inverse problem of the electromagnetic tomography (EMT) are derived, whose kernel is the dyadic Green's function for the EMT sensor with a homogeneous medium in the object space. Then in terms of ill-posedness of the inverse problem, a Tikhonov-type regularization model is established based on a linearization-approximation of the nonlinear inverse problem. Finally, an iterative algorithm of image reconstruction based on the inverse problem and reconstruction images of some object flows for simplified sensor are given. Initial results of the image reconstruction show that the algorithm based on the inverse problem is superior to those based on the linear back-projection in the quality of image reconstruction.

  8. Knowledge-based automated radiopharmaceutical manufacturing for Positron Emission Tomography

    International Nuclear Information System (INIS)

    This article describes the application of basic knowledge engineering principles to the design of automated synthesis equipment for radiopharmaceuticals used in Positron Emission Tomography (PET). Before discussing knowledge programming, an overview of the development of automated radiopharmaceutical synthesis systems for PET will be presented. Since knowledge systems will rely on information obtained from machine transducers, a discussion of the uses of sensory feedback in today's automated systems follows. Next, the operation of these automated systems is contrasted to radiotracer production carried out by chemists, and the rationale for and basic concepts of knowledge-based programming are explained. Finally, a prototype knowledge-based system supporting automated radiopharmaceutical manufacturing of 18FDG at Brookhaven National Laboratory (BNL) is described using 1stClass, a commercially available PC-based expert system shell

  9. Bioluminescence imaging in live cells and animals.

    Science.gov (United States)

    Tung, Jack K; Berglund, Ken; Gutekunst, Claire-Anne; Hochgeschwender, Ute; Gross, Robert E

    2016-04-01

    The use of bioluminescent reporters in neuroscience research continues to grow at a rapid pace as their applications and unique advantages over conventional fluorescent reporters become more appreciated. Here, we describe practical methods and principles for detecting and imaging bioluminescence from live cells and animals. We systematically tested various components of our conventional fluorescence microscope to optimize it for long-term bioluminescence imaging. High-resolution bioluminescence images from live neurons were obtained with our microscope setup, which could be continuously captured for several hours with no signs of phototoxicity. Bioluminescence from the mouse brain was also imaged noninvasively through the intact skull with a conventional luminescence imager. These methods demonstrate how bioluminescence can be routinely detected and measured from live cells and animals in a cost-effective way with common reagents and equipment.

  10. Protein-protein complexation in bioluminescence

    OpenAIRE

    Titushin, Maxim S.; Feng, Yingang; Lee, John; Vysotski, Eugene S.; Liu, Zhi-jie

    2011-01-01

    In this review we summarize the progress made towards understanding the role of protein-protein interactions in the function of various bioluminescence systems of marine organisms, including bacteria, jellyfish and soft corals, with particular focus on methodology used to detect and characterize these interactions. In some bioluminescence systems, protein-protein interactions involve an “accessory protein” whereby a stored substrate is efficiently delivered to the bioluminescent enzyme lucife...

  11. Quantification of the vascular endothelial growth factor with a bioluminescence resonance energy transfer (BRET) based single molecule biosensor.

    Science.gov (United States)

    Wimmer, T; Lorenz, B; Stieger, K

    2016-12-15

    Neovascular pathologies in the eye like age-related macular degeneration (AMD), the diabetic retinopathie (DR), retinopathie of prematurity (ROP) or the retinal vein occlusion (RVO) are caused through a hypoxia induced upregulation of the vascular endothelial growth factor (VEGF). So far a correlation of intraocular VEGF concentrations to the impact of the pathologies is limited because of invasive sampling. Therefore, a minimally invasive, repeatable quantification of VEGF levels in the eye is needed to correlate the stage of VEGF induced pathologies as well as the efficacy of anti-VEGF treatment. Here we describe the development of three variants of enhanced BRET2 (eBRET2) based, single molecule biosensors by fusing a Renilla luciferase mutant with enhanced light output (RLuc8) to the N-terminus and a suitable eBRET2 acceptor fluorophore (GFP2) to the C-terminus of a VEGF binding domain, directly fused or separated with two different peptide linkers for the quantification of VEGF in vitro. The VEGF binding domain consists of a single chain variable fragment (scFv) based on ranibizumab in which the light- and the heavy- F(ab) chains were connected with a peptide linker to generate one open reading frame (orf). All three variants generate measureable eBRET2 ratios by transferring energy from the luciferase donor to the GFP2 acceptor, whereas only the directly fused and the proline variant permit VEGF quantification. The directly fused biosensor variant allows the quantification of VEGF with higher sensitivity, compared to the widely used ELISA systems and a wide dynamic quantification range in vitro. Our system demonstrates not only an additional in vitro application on VEGF quantification but also a promising step towards an applicable biosensor in an implantable device able to quantify VEGF reliably after implantation in vivo. PMID:27459244

  12. Quantification of the vascular endothelial growth factor with a bioluminescence resonance energy transfer (BRET) based single molecule biosensor.

    Science.gov (United States)

    Wimmer, T; Lorenz, B; Stieger, K

    2016-12-15

    Neovascular pathologies in the eye like age-related macular degeneration (AMD), the diabetic retinopathie (DR), retinopathie of prematurity (ROP) or the retinal vein occlusion (RVO) are caused through a hypoxia induced upregulation of the vascular endothelial growth factor (VEGF). So far a correlation of intraocular VEGF concentrations to the impact of the pathologies is limited because of invasive sampling. Therefore, a minimally invasive, repeatable quantification of VEGF levels in the eye is needed to correlate the stage of VEGF induced pathologies as well as the efficacy of anti-VEGF treatment. Here we describe the development of three variants of enhanced BRET2 (eBRET2) based, single molecule biosensors by fusing a Renilla luciferase mutant with enhanced light output (RLuc8) to the N-terminus and a suitable eBRET2 acceptor fluorophore (GFP2) to the C-terminus of a VEGF binding domain, directly fused or separated with two different peptide linkers for the quantification of VEGF in vitro. The VEGF binding domain consists of a single chain variable fragment (scFv) based on ranibizumab in which the light- and the heavy- F(ab) chains were connected with a peptide linker to generate one open reading frame (orf). All three variants generate measureable eBRET2 ratios by transferring energy from the luciferase donor to the GFP2 acceptor, whereas only the directly fused and the proline variant permit VEGF quantification. The directly fused biosensor variant allows the quantification of VEGF with higher sensitivity, compared to the widely used ELISA systems and a wide dynamic quantification range in vitro. Our system demonstrates not only an additional in vitro application on VEGF quantification but also a promising step towards an applicable biosensor in an implantable device able to quantify VEGF reliably after implantation in vivo.

  13. A bioluminescent assay for measuring glucose uptake.

    Science.gov (United States)

    Valley, Michael P; Karassina, Natasha; Aoyama, Natsuyo; Carlson, Coby; Cali, James J; Vidugiriene, Jolanta

    2016-07-15

    Identifying activators and inhibitors of glucose uptake is critical for both diabetes management and anticancer therapy. To facilitate such studies, easy-to-use nonradioactive assays are desired. Here we describe a bioluminescent glucose uptake assay for measuring glucose transport in cells. The assay is based on the uptake of 2-deoxyglucose and the enzymatic detection of the 2-deoxyglucose-6-phosphate that accumulates. Uptake can be measured from a variety of cell types, it can be inhibited by known glucose transporter inhibitors, and the bioluminescent assay yields similar results when compared with the radioactive method. With HCT 116 cells, glucose uptake can be detected in as little as 5000 cells and remains linear up to 50,000 cells with signal-to-background values ranging from 5 to 45. The assay can be used to screen for glucose transporter inhibitors, or by multiplexing with viability readouts, changes in glucose uptake can be differentiated from overall effects on cell health. The assay also can provide a relevant end point for measuring insulin sensitivity. With adipocytes and myotubes, insulin-dependent increases in glucose uptake have been measured with 10- and 2-fold assay windows, respectively. Significant assay signals of 2-fold or more have also been measured with human induced pluripotent stem cell (iPSC)-derived cardiomyocytes and skeletal myoblasts. PMID:27130501

  14. Matrix-based image reconstruction methods for tomography

    International Nuclear Information System (INIS)

    Matrix methods of image reconstruction have not been used, in general, because of the large size of practical matrices, ill condition upon inversion and the success of Fourier-based techniques. An exception is the work that has been done at the Lawrence Berkeley Laboratory for imaging with accelerated radioactive ions. An extension of that work into more general imaging problems shows that, with a correct formulation of the problem, positron tomography with ring geometries results in well behaved matrices which can be used for image reconstruction with no distortion of the point response in the field of view and flexibility in the design of the instrument. Maximum Likelihood Estimator methods of reconstruction, which use the system matrices tailored to specific instruments and do not need matrix inversion, are shown to result in good preliminary images. A parallel processing computer structure based on multiple inexpensive microprocessors is proposed as a system to implement the matrix-MLE methods. 14 references, 7 figures

  15. Electrical impedance tomography system based on active electrodes

    International Nuclear Information System (INIS)

    Electrical impedance tomography (EIT) can image the distribution of ventilated lung tissue, and is thus a promising technology to help monitor patient breathing to help selection of mechanical ventilation parameters. Two key difficulties in EIT instrumentation make such monitoring difficult: (1) EIT data quality depends on good electrode contact and is sensitive to changes in contact quality, and (2) EIT electrodes are difficult and time consuming to place on patients. This paper presents the design and initial tests of an active electrode-based system to address these difficulties. Our active electrode EIT system incorporates an active electrode belt, a central voltage-driven current source, central analog to digital converters and digital to analog converters, a central FPGA-based demodulator and controller. The electrode belt is designed incorporating 32 active electrodes, each of which contains the electronic amplifiers, switches and associated logic. Tests show stable device performance with a convenient ease of use and good imaging ability in volunteer tests. (paper)

  16. Introducing shape constraints into object-based traveltime tomography

    Science.gov (United States)

    Gaullier, G.; Charbonnier, P.; Heitz, F.; Côte, P.

    2016-09-01

    Traveltime tomography is a difficult, ill-posed reconstruction problem due to the nonlinearity of the forward model and the limited number of measurements usually available. In such an adverse situation, pixel-based regularization methods are generally unable to provide satisfactory reconstructions. In this paper we propose a novel object-based reconstruction method that introduces prior information about the shape of the structures to be reconstructed, which yields high quality geoacoustic inversion. The proposed method approaches the forward model by a series of linear problems, leading to a sequence of minimizations during which the shape prior is introduced. The method is demonstrated on synthetic and real data, collected on a specific bench dedicated to non-destructive testing of civil engineering structures.

  17. Hydromechanical stimulation of bioluminescent plankton.

    Science.gov (United States)

    Blaser, Stefan; Kurisu, Futoshi; Satoh, Hiroyasu; Mino, Takashi

    2002-01-01

    The response of the bioluminescent dinoflagellate Pyrocystis fusiformis was investigated for different hydraulic conditions ('hydromechanical stimulation'). Pipe flow and oscillating shear produced luminescence, whereas changes in hydrostatic pressure were not stimulating. More intense fluid motion led to higher intensity, mainly due to a higher probability of cell response. The organism was also able to emit light in a glucose-salt mixture. The experiments suggest that the cells are effectively stimulated if the flow conditions change in time.

  18. Line-Source Based X-Ray Tomography

    Directory of Open Access Journals (Sweden)

    Deepak Bharkhada

    2009-01-01

    Full Text Available Current computed tomography (CT scanners, including micro-CT scanners, utilize a point x-ray source. As we target higher and higher spatial resolutions, the reduced x-ray focal spot size limits the temporal and contrast resolutions achievable. To overcome this limitation, in this paper we propose to use a line-shaped x-ray source so that many more photons can be generated, given a data acquisition interval. In reference to the simultaneous algebraic reconstruction technique (SART algorithm for image reconstruction from projection data generated by an x-ray point source, here we develop a generalized SART algorithm for image reconstruction from projection data generated by an x-ray line source. Our numerical simulation results demonstrate the feasibility of our novel line-source based x-ray CT approach and the proposed generalized SART algorithm.

  19. Diffraction tomography on curved boundaries: A projection-based approach

    CERN Document Server

    Clement, G T

    2013-01-01

    An approach to diffraction tomography is investigated for two-dimensional image reconstruction of objects surrounded by an arbitrarily-shaped curve of sources and receivers. Based on the integral theorem of Helmholtz and Kirchhoff, the approach relies upon a valid choice of the Green's functions for selected conditions along the (possibly-irregular) boundary. This allows field projections from the receivers to an arbitrary external location. When performed over all source locations, it will be shown that the field caused by a hypothetical source at this external location is also known along the boundary. This field can then be projected to new external points that may serve as a virtual receiver. Under such a reformation, data may be put in a form suitable for image construction by synthetic aperture methods. Foundations of the approach are shown, followed by a mapping technique optimized for the approach. Examples formed from synthetic data are provided.

  20. An energy-based beam hardening model in tomography

    Energy Technology Data Exchange (ETDEWEB)

    Casteele, E van de; Dyck, D van; Sijbers, J; Raman, E [Vision Lab, Physics Departement, University of Antwerp (RUCA) (Belgium)

    2002-12-07

    As a consequence of the polychromatic x-ray source, used in micro-computer tomography ({mu}CT) and in medical CT, the attenuation is no longer a linear function of absorber thickness. If this nonlinear beam hardening effect is not compensated, the reconstructed images will be corrupted by cupping artefacts. In this paper, a bimodal energy model for the detected energy spectrum is presented, which can be used for reduction of artefacts caused by beam hardening in well-specified conditions. Based on the combination of the spectrum of the source and the detector efficiency, the assumption is made that there are two dominant energies which can describe the system. The validity of the proposed model is examined by fitting the model to the experimental datapoints obtained on a microtomograph for different materials and source voltages.

  1. Voidage measurement based on genetic algorithm and electrical capacitance tomography

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-wei; WANG Bao-liang; HUANG Zhi-yao; LI Hai-qing

    2005-01-01

    A new voidage measurement method based on electrical capacitance tomography (ECT) technique, Genetic Algorithm (GA) and Partial Least Square (PLS) method was proposed. The voidage measurement model, linear capacitance combination, was developed to measure on-line voidage. GA and PLS method were used to determine the coefficients of the voidage measurement model. GA was used to explore the optimal capacitance combination which gave significant contribution to the voidage measurement. PLS method was applied to determine the weight coefficient of the contribution of each capacitance to the voidage measurement. Flow pattern identification result was introduced to improve the voidage measurement accuracy. Experimental results showed that the proposed voidage measurement method is effective and that the measurement accuracy is satisfactory.

  2. An objective method to assess bioluminescent properties of selected bacterial strains

    Directory of Open Access Journals (Sweden)

    Bożena Danyluk

    2007-12-01

    Full Text Available Emission of light as a result of biochemical activities of some living bacteria Vibrio fischeri (in the past known as Photobacterium phosphoreum makes it possible to monitor environmental changes in ecosystems. Toxicity testing as an international standard operating procedure based on the use of this method has already been accepted. The bioluminescent test offers a rapid, simple and sensitive method to test a wide spectrum of chemical substances and environmental samples including water, wastewater, sludge extracts, etc. In this study, aimed at characterising and comparing bioluminescent properties, four different bacterial strains were cultivated in four different liquid mediums and temperature conditions. The bioluminescent intensity of bacterial suspensions was measured using a laboratory BioOrbit 1253 luminometer during bacteria culture. Based on obtained results and mathematical calculations of RLU (relative luminescent units values strain Photobacterium phosphoreum + NCBE medium were indicated as the variant demonstrating proper bioluminescence intensity and characteristics most suitable for further applications.

  3. REVIEW OF ENVIRONMENTAL APPLICATIONS OF BIOLUMINESCENCE MEASUREMENTS

    Science.gov (United States)

    This review of the recent literature on environmental applications of bioluminescence systems will focus on in vivo and in vitro bioluminescence methods that have been utilized to elucidate properties of chemicals, toxic and mutagenic effects, and to estimate biomass. he unifying...

  4. Scattered Neutron Tomography Based on A Neutron Transport Inverse Problem

    Energy Technology Data Exchange (ETDEWEB)

    William Charlton

    2007-07-01

    Neutron radiography and computed tomography are commonly used techniques to non-destructively examine materials. Tomography refers to the cross-sectional imaging of an object from either transmission or reflection data collected by illuminating the object from many different directions.

  5. Understanding bioluminescence in dinoflagellates — how far have we come?

    OpenAIRE

    Martha Valiadi; Debora Iglesias-Rodriguez

    2013-01-01

    Some dinoflagellates possess the remarkable genetic, biochemical, and cellular machinery to produce bioluminescence. Bioluminescent species appear to be ubiquitous in surface waters globally and include numerous cosmopolitan and harmful taxa. Nevertheless, bioluminescence remains an enigmatic topic in biology, particularly with regard to the organisms’ lifestyle. In this paper, we review the literature on the cellular mechanisms, molecular evolution, diversity, and ecology of bioluminescence ...

  6. Formulation of photon diffusion from spherical bioluminescent sources in an infinite homogeneous medium

    Directory of Open Access Journals (Sweden)

    Wang Lihong V

    2004-05-01

    computationally efficient in biomedical engineering applications. By using our analytic solutions for spherical sources, we can better predict bioluminescent signals and better understand both the potential for, and the limitations of, bioluminescent tomography in an idealized case. The formulas are particularly valuable for furthering the development of bioluminescent tomography.

  7. Bioluminescence imaging characteristics and application

    International Nuclear Information System (INIS)

    Bioluminescence imaging (BLI) by luciferase gene marked cells or DNA, in the presence of ATP and oxygen, catalytic oxidation reaction of fluorescein luminescence. So that it can directly monitor in vivo cell activity and gene behavior. In this paper, by comparing the BLI and MRI, PET, radiography of the similarities and differences, as well as about their cancer, stem cells and immune cells transportation, apoptosis and other aspects of the application, in order to better provide the basis for promoting the application of BLI. (authors)

  8. Cyst-based measurements for assessing lymphangioleiomyomatosis in computed tomography

    International Nuclear Information System (INIS)

    Purpose: To investigate the efficacy of a new family of measurements made on individual pulmonary cysts extracted from computed tomography (CT) for assessing the severity of lymphangioleiomyomatosis (LAM). Methods: CT images were analyzed using thresholding to identify a cystic region of interest from chest CT of LAM patients. Individual cysts were then extracted from the cystic region by the watershed algorithm, which separates individual cysts based on subtle edges within the cystic regions. A family of measurements were then computed, which quantify the amount, distribution, and boundary appearance of the cysts. Sequential floating feature selection was used to select a small subset of features for quantification of the severity of LAM. Adjusted R2 from multiple linear regression and R2 from linear regression against measurements from spirometry were used to compare the performance of our proposed measurements with currently used density based CT measurements in the literature, namely, the relative area measure and the D measure. Results: Volumetric CT data, performed at total lung capacity and residual volume, from a total of 49 subjects enrolled in the MILES trial were used in our study. Our proposed measures had adjusted R2 ranging from 0.42 to 0.59 when regressing against the spirometry measures, with p < 0.05. For previously used density based CT measurements in the literature, the best R2 was 0.46 (for only one instance), with the majority being lower than 0.3 or p > 0.05. Conclusions: The proposed family of CT-based cyst measurements have better correlation with spirometric measures than previously used density based CT measurements. They show potential as a sensitive tool for quantitatively assessing the severity of LAM

  9. Cyst-based measurements for assessing lymphangioleiomyomatosis in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lo, P., E-mail: pechinlo@mednet.edu.ucla; Brown, M. S.; Kim, H.; Kim, H.; Goldin, J. G. [Center for Computer Vision and Imaging Biomarkers, Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California 90024 (United States); Argula, R.; Strange, C. [Division of Pulmonary and Critical Care Medicine, Medical University of South Carolina, Charleston, South Carolina 29425 (United States)

    2015-05-15

    Purpose: To investigate the efficacy of a new family of measurements made on individual pulmonary cysts extracted from computed tomography (CT) for assessing the severity of lymphangioleiomyomatosis (LAM). Methods: CT images were analyzed using thresholding to identify a cystic region of interest from chest CT of LAM patients. Individual cysts were then extracted from the cystic region by the watershed algorithm, which separates individual cysts based on subtle edges within the cystic regions. A family of measurements were then computed, which quantify the amount, distribution, and boundary appearance of the cysts. Sequential floating feature selection was used to select a small subset of features for quantification of the severity of LAM. Adjusted R{sup 2} from multiple linear regression and R{sup 2} from linear regression against measurements from spirometry were used to compare the performance of our proposed measurements with currently used density based CT measurements in the literature, namely, the relative area measure and the D measure. Results: Volumetric CT data, performed at total lung capacity and residual volume, from a total of 49 subjects enrolled in the MILES trial were used in our study. Our proposed measures had adjusted R{sup 2} ranging from 0.42 to 0.59 when regressing against the spirometry measures, with p < 0.05. For previously used density based CT measurements in the literature, the best R{sup 2} was 0.46 (for only one instance), with the majority being lower than 0.3 or p > 0.05. Conclusions: The proposed family of CT-based cyst measurements have better correlation with spirometric measures than previously used density based CT measurements. They show potential as a sensitive tool for quantitatively assessing the severity of LAM.

  10. Roles of biogenic amines in regulating bioluminescence in the Australian glowworm Arachnocampa flava.

    Science.gov (United States)

    Rigby, Lisa M; Merritt, David J

    2011-10-01

    The glowworm Arachnocampa flava is a carnivorous fly larva (Diptera) that uses light to attract prey into its web. The light organ is derived from cells of the Malpighian tubules, representing a bioluminescence system that is unique to the genus. Bioluminescence is modulated through the night although light levels change quite slowly compared with the flashing of the better-known fireflies (Coleoptera). The existing model for the neural regulation of bioluminescence in Arachnocampa, based on use of anaesthetics and ligations, is that bioluminescence is actively repressed during the non-glowing phase and the repression is partially released during the bioluminescence phase. The effect of the anaesthetic, carbon dioxide, on the isolated light organ from the present study indicates that the repression is at least partially mediated at the light organ itself rather than less directly through the central nervous system. Blocking of neural signals from the central nervous system through ligation leads to uncontrolled release of bioluminescence but light is emitted at relatively low levels compared with under anaesthesia. Candidate biogenic amines were introduced by several methods: feeding prey items injected with test solution, injecting the whole larva, injecting a ligated section containing the light organ or bathing the isolated light organ in test solution. Using these methods, dopamine, serotonin and tyramine do not affect bioluminescence output. Exposure to elevated levels of octopamine via feeding, injection or bathing of the isolated light organ indicates that it is involved in the regulation of repression. Administration of the octopamine antagonists phentolamine or mianserin results in very high bioluminescence output levels, similar to the effect of anaesthetics, but only mianserin acts directly on the light organ.

  11. Discovery of a glowing millipede in California and the gradual evolution of bioluminescence in Diplopoda.

    Science.gov (United States)

    Marek, Paul E; Moore, Wendy

    2015-05-19

    The rediscovery of the Californian millipede Xystocheir bistipita surprisingly reveals that the species is bioluminescent. Using molecular phylogenetics, we show that X. bistipita is the evolutionary sister group of Motyxia, the only genus of New World bioluminescent millipedes. We demonstrate that bioluminescence originated in the group's most recent common ancestor and evolved by gradual, directional change through diversification. Because bioluminescence in Motyxia has been experimentally demonstrated to be aposematic, forewarning of the animal's cyanide-based toxins, these results are contrary to aposematic theory and empirical evidence that a warning pattern cannot evolve gradually in unpalatable prey. However, gradual evolution of a warning pattern is plausible if faint light emission served another function and was co-opted as an aposematic signal later in the diversification of the genus. Luminescence in Motyxia stem-group taxa may have initially evolved to cope with reactive oxygen stress triggered by a hot, dry environment and was repurposed for aposematism by high-elevation crown-group taxa colonizing new habitats with varying levels of predation. The discovery of bioluminescence in X. bistipita and its pivotal phylogenetic location provides insight into the independent and repeated evolution of bioluminescence across the tree of life.

  12. Computed tomography-based training model for otoplasty.

    Science.gov (United States)

    Schneider, Gerlind; Voigt, Sibylle; Rettinger, Gerhard

    2016-09-01

    Otoplasty for the correction of protruding ears is characterized by various techniques and a common and popular cosmetic procedure. For the surgeon, whether beginner or advanced, it is essential to understand the principles and master techniques for standard auricular deformities before applying further sophisticated methods, because a lot of complications and failures are caused by wrong indication and incorrect surgical techniques. The different surgical steps are best learned from teaching models. Therefore, we developed two different silicone models of protruding ears with moderate auricular deformities: one with conchal hyperplasia for the training of conchal resection, and one without antihelix for creating an antihelical fold by suturing technique, based on computed tomography scans of patients. The silicone ear models were evaluated during four standardized surgery courses for residents in otorhinolaryngology by 91 participants using specially designed questionnaires. Nearly all participants rated the training on the auricular models as very helpful (n = 51) or good (n = 31); the scores for the different techniques and properties of the models ranged from 2.0 to 2.6 in a range from 1 (very good) to 4 (inadequate). The good results demonstrate the possibility for learning different surgical otoplasty techniques with this newly designed teaching tool. PMID:26541715

  13. Video-rate volumetric optical coherence tomography-based microangiography

    Science.gov (United States)

    Baran, Utku; Wei, Wei; Xu, Jingjiang; Qi, Xiaoli; Davis, Wyatt O.; Wang, Ruikang K.

    2016-04-01

    Video-rate volumetric optical coherence tomography (vOCT) is relatively young in the field of OCT imaging but has great potential in biomedical applications. Due to the recent development of the MHz range swept laser sources, vOCT has started to gain attention in the community. Here, we report the first in vivo video-rate volumetric OCT-based microangiography (vOMAG) system by integrating an 18-kHz resonant microelectromechanical system (MEMS) mirror with a 1.6-MHz FDML swept source operating at ˜1.3 μm wavelength. Because the MEMS scanner can offer an effective B-frame rate of 36 kHz, we are able to engineer vOMAG with a video rate up to 25 Hz. This system was utilized for real-time volumetric in vivo visualization of cerebral microvasculature in mice. Moreover, we monitored the blood perfusion dynamics during stimulation within mouse ear in vivo. We also discussed this system's limitations. Prospective MEMS-enabled OCT probes with a real-time volumetric functional imaging capability can have a significant impact on endoscopic imaging and image-guided surgery applications.

  14. Bioluminescence imaging: a shining future for cardiac regeneration

    OpenAIRE

    Roura, Santiago; Gálvez-Montón, Carolina; Bayes-Genis, Antoni

    2013-01-01

    Advances in bioanalytical techniques have become crucial for both basic research and medical practice. One example, bioluminescence imaging (BLI), is based on the application of natural reactants with light-emitting capabilities (photoproteins and luciferases) isolated from a widespread group of organisms. The main challenges in cardiac regeneration remain unresolved, but a vast number of studies have harnessed BLI with the discovery of aequorin and green fluorescent proteins. First described...

  15. The Chemical Basis of Fungal Bioluminescence.

    Science.gov (United States)

    Purtov, Konstantin V; Petushkov, Valentin N; Baranov, Mikhail S; Mineev, Konstantin S; Rodionova, Natalja S; Kaskova, Zinaida M; Tsarkova, Aleksandra S; Petunin, Alexei I; Bondar, Vladimir S; Rodicheva, Emma K; Medvedeva, Svetlana E; Oba, Yuichi; Oba, Yumiko; Arseniev, Alexander S; Lukyanov, Sergey; Gitelson, Josef I; Yampolsky, Ilia V

    2015-07-01

    Many species of fungi naturally produce light, a phenomenon known as bioluminescence, however, the fungal substrates used in the chemical reactions that produce light have not been reported. We identified the fungal compound luciferin 3-hydroxyhispidin, which is biosynthesized by oxidation of the precursor hispidin, a known fungal and plant secondary metabolite. The fungal luciferin does not share structural similarity with the other eight known luciferins. Furthermore, it was shown that 3-hydroxyhispidin leads to bioluminescence in extracts from four diverse genera of luminous fungi, thus suggesting a common biochemical mechanism for fungal bioluminescence.

  16. Analysis of forest backscattering characteristics based on polarization coherence tomography

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is difficult to make an inventory of vertical profiles of forest structure parameters in field measurements.However,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure parameters.The vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2-D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site Traunstein.Firstly,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical simulation.Secondly,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and analyzed.Then a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also discussed.Preliminary results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and density.Finally,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

  17. Repeated and Widespread Evolution of Bioluminescence in Marine Fishes.

    Science.gov (United States)

    Davis, Matthew P; Sparks, John S; Smith, W Leo

    2016-01-01

    Bioluminescence is primarily a marine phenomenon with 80% of metazoan bioluminescent genera occurring in the world's oceans. Here we show that bioluminescence has evolved repeatedly and is phylogenetically widespread across ray-finned fishes. We recover 27 independent evolutionary events of bioluminescence, all among marine fish lineages. This finding indicates that bioluminescence has evolved many more times than previously hypothesized across fishes and the tree of life. Our exploration of the macroevolutionary patterns of bioluminescent lineages indicates that the present day diversity of some inshore and deep-sea bioluminescent fish lineages that use bioluminescence for communication, feeding, and reproduction exhibit exceptional species richness given clade age. We show that exceptional species richness occurs particularly in deep-sea fishes with intrinsic bioluminescent systems and both shallow water and deep-sea lineages with luminescent systems used for communication.

  18. Repeated and Widespread Evolution of Bioluminescence in Marine Fishes.

    Science.gov (United States)

    Davis, Matthew P; Sparks, John S; Smith, W Leo

    2016-01-01

    Bioluminescence is primarily a marine phenomenon with 80% of metazoan bioluminescent genera occurring in the world's oceans. Here we show that bioluminescence has evolved repeatedly and is phylogenetically widespread across ray-finned fishes. We recover 27 independent evolutionary events of bioluminescence, all among marine fish lineages. This finding indicates that bioluminescence has evolved many more times than previously hypothesized across fishes and the tree of life. Our exploration of the macroevolutionary patterns of bioluminescent lineages indicates that the present day diversity of some inshore and deep-sea bioluminescent fish lineages that use bioluminescence for communication, feeding, and reproduction exhibit exceptional species richness given clade age. We show that exceptional species richness occurs particularly in deep-sea fishes with intrinsic bioluminescent systems and both shallow water and deep-sea lineages with luminescent systems used for communication. PMID:27276229

  19. Repeated and Widespread Evolution of Bioluminescence in Marine Fishes

    Science.gov (United States)

    Davis, Matthew P.; Sparks, John S.; Smith, W. Leo

    2016-01-01

    Bioluminescence is primarily a marine phenomenon with 80% of metazoan bioluminescent genera occurring in the world’s oceans. Here we show that bioluminescence has evolved repeatedly and is phylogenetically widespread across ray-finned fishes. We recover 27 independent evolutionary events of bioluminescence, all among marine fish lineages. This finding indicates that bioluminescence has evolved many more times than previously hypothesized across fishes and the tree of life. Our exploration of the macroevolutionary patterns of bioluminescent lineages indicates that the present day diversity of some inshore and deep-sea bioluminescent fish lineages that use bioluminescence for communication, feeding, and reproduction exhibit exceptional species richness given clade age. We show that exceptional species richness occurs particularly in deep-sea fishes with intrinsic bioluminescent systems and both shallow water and deep-sea lineages with luminescent systems used for communication. PMID:27276229

  20. Quantitative bioluminescence imaging of mouse tumor models.

    Science.gov (United States)

    Tseng, Jen-Chieh; Kung, Andrew L

    2015-01-05

    Bioluminescence imaging (BLI) has become an essential technique for preclinical evaluation of anticancer therapeutics and provides sensitive and quantitative measurements of tumor burden in experimental cancer models. For light generation, a vector encoding firefly luciferase is introduced into human cancer cells that are grown as tumor xenografts in immunocompromised hosts, and the enzyme substrate luciferin is injected into the host. Alternatively, the reporter gene can be expressed in genetically engineered mouse models to determine the onset and progression of disease. In addition to expression of an ectopic luciferase enzyme, bioluminescence requires oxygen and ATP, thus only viable luciferase-expressing cells or tissues are capable of producing bioluminescence signals. Here, we summarize a BLI protocol that takes advantage of advances in hardware, especially the cooled charge-coupled device camera, to enable detection of bioluminescence in living animals with high sensitivity and a large dynamic range.

  1. Analytical Applications of Bioluminescence and Chemiluminescence

    Science.gov (United States)

    Chappelle, E. W. (Editor); Picciolo, G. L. (Editor)

    1975-01-01

    Bioluminescence and chemiluminescence studies were used to measure the amount of adenosine triphosphate and therefore the amount of energy available. Firefly luciferase - luciferin enzyme system was emphasized. Photometer designs are also considered.

  2. Global seismic waveform tomography based on the spectral element method.

    Science.gov (United States)

    Capdeville, Y.; Romanowicz, B.; Gung, Y.

    2003-04-01

    Because seismogram waveforms contain much more information on the earth structure than body wave time arrivals or surface wave phase velocities, inversion of complete time-domain seismograms should allow much better resolution in global tomography. In order to achieve this, accurate methods for the calculation of forward propagation of waves in a 3D earth need to be utilized, which presents theoretical as well as computational challenges. In the past 8 years, we have developed several global 3D S velocity models based on long period waveform data, and a normal mode asymptotic perturbation formalism (NACT, Li and Romanowicz, 1996). While this approach is relatively accessible from the computational point of view, it relies on the assumption of smooth heterogeneity in a single scattering framework. Recently, the introduction of the spectral element method (SEM) has been a major step forward in the computation of seismic waveforms in a global 3D earth with no restrictions on the size of heterogeneities (Chaljub, 2000). While this method is computationally heavy when the goal is to compute large numbers of seismograms down to typical body wave periods (1-10 sec), it is much more accessible when restricted to low frequencies (T>150sec). When coupled with normal modes (e.g. Capdeville et al., 2000), the numerical computation can be restricted to a spherical shell within which heterogeneity is considered, further reducing the computational time. Here, we present a tomographic method based on the non linear least square inversion of time domain seismograms using the coupled method of spectral elements and modal solution. SEM/modes are used for both the forward modeling and to compute partial derivatives. The parametrisation of the model is also based on the spectral element mesh, the "cubed sphere" (Sadourny, 1972), which leads to a 3D local polynomial parametrization. This parametrization, combined with the excellent earth coverage resulting from the full 3D theory used

  3. Dictionary-based image denoising for dual energy computed tomography

    Science.gov (United States)

    Mechlem, Korbinian; Allner, Sebastian; Mei, Kai; Pfeiffer, Franz; Noël, Peter B.

    2016-03-01

    Compared to conventional computed tomography (CT), dual energy CT allows for improved material decomposition by conducting measurements at two distinct energy spectra. Since radiation exposure is a major concern in clinical CT, there is a need for tools to reduce the noise level in images while preserving diagnostic information. One way to achieve this goal is the application of image-based denoising algorithms after an analytical reconstruction has been performed. We have developed a modified dictionary denoising algorithm for dual energy CT aimed at exploiting the high spatial correlation between between images obtained from different energy spectra. Both the low-and high energy image are partitioned into small patches which are subsequently normalized. Combined patches with improved signal-to-noise ratio are formed by a weighted addition of corresponding normalized patches from both images. Assuming that corresponding low-and high energy image patches are related by a linear transformation, the signal in both patches is added coherently while noise is neglected. Conventional dictionary denoising is then performed on the combined patches. Compared to conventional dictionary denoising and bilateral filtering, our algorithm achieved superior performance in terms of qualitative and quantitative image quality measures. We demonstrate, in simulation studies, that this approach can produce 2d-histograms of the high- and low-energy reconstruction which are characterized by significantly improved material features and separation. Moreover, in comparison to other approaches that attempt denoising without simultaneously using both energy signals, superior similarity to the ground truth can be found with our proposed algorithm.

  4. A practical local tomography reconstruction algorithm based on known subregion

    CERN Document Server

    Paleo, Pierre; Mirone, Alessandro

    2016-01-01

    We propose a new method to reconstruct data acquired in a local tomography setup. This method uses an initial reconstruction and refines it by correcting the low frequency artifacts known as the cupping effect. A basis of Gaussian functions is used to correct the initial reconstruction. The coefficients of this basis are iteratively optimized under the constraint of a known subregion. Using a coarse basis reduces the degrees of freedom of the problem while actually correcting the cupping effect. Simulations show that the known region constraint yields an unbiased reconstruction, in accordance to uniqueness theorems stated in local tomography.

  5. Optical Doppler tomography based on a field programmable gate array

    DEFF Research Database (Denmark)

    Larsen, Henning Engelbrecht; Nilsson, Ronnie Thorup; Thrane, Lars;

    2008-01-01

    We report the design of and results obtained by using a field programmable gate array (FPGA) to digitally process optical Doppler tomography signals. The processor fits into the analog signal path in an existing optical coherence tomography setup. We demonstrate both Doppler frequency and envelope...... extraction using the Hilbert transform, all in a single FPGA. An FPGA implementation has certain advantages over general purpose digital signal processor (DSP) due to the fact that the processing elements operate in parallel as opposed to the DSP. which is primarily a sequential processor....

  6. Circadian control sheds light on fungal bioluminescence.

    Science.gov (United States)

    Oliveira, Anderson G; Stevani, Cassius V; Waldenmaier, Hans E; Viviani, Vadim; Emerson, Jillian M; Loros, Jennifer J; Dunlap, Jay C

    2015-03-30

    Bioluminescence, the creation and emission of light by organisms, affords insight into the lives of organisms doing it. Luminous living things are widespread and access diverse mechanisms to generate and control luminescence [1-5]. Among the least studied bioluminescent organisms are phylogenetically rare fungi-only 71 species, all within the ∼ 9,000 fungi of the temperate and tropical Agaricales order-are reported from among ∼ 100,000 described fungal species [6, 7]. All require oxygen [8] and energy (NADH or NADPH) for bioluminescence and are reported to emit green light (λmax 530 nm) continuously, implying a metabolic function for bioluminescence, perhaps as a byproduct of oxidative metabolism in lignin degradation. Here, however, we report that bioluminescence from the mycelium of Neonothopanus gardneri is controlled by a temperature-compensated circadian clock, the result of cycles in content/activity of the luciferase, reductase, and luciferin that comprise the luminescent system. Because regulation implies an adaptive function for bioluminescence, a controversial question for more than two millennia [8-15], we examined interactions between luminescent fungi and insects [16]. Prosthetic acrylic resin "mushrooms," internally illuminated by a green LED emitting light similar to the bioluminescence, attract staphilinid rove beetles (coleopterans), as well as hemipterans (true bugs), dipterans (flies), and hymenopterans (wasps and ants), at numbers far greater than dark control traps. Thus, circadian control may optimize energy use for when bioluminescence is most visible, attracting insects that can in turn help in spore dispersal, thereby benefitting fungi growing under the forest canopy, where wind flow is greatly reduced.

  7. MEASUREMENTS OF BIOLUMINESCENCE IN DEEP SEA

    OpenAIRE

    Chikawa, M.; Kitamura, T; Nakagawa, Nakagawa; Yamamoto, I.; Wada, T.; Okei, K; Yamashita, Y.

    1996-01-01

    [Abstract] We have designed and built a photon counting system which measures low intensities of bioluminescence in deep sea. The system comprises a CCD-TV camera, two-dimensional image intensifier and video cassette recorder. Using this system we measured the vertical profile of bioluminescence in situ at the Suruga Trough and Nankai Trough to a depth of 3600 m and analyzed cultivated them.

  8. Noninvasive Bioluminescence Imaging in Small Animals

    OpenAIRE

    Zinn, Kurt R.; Chaudhuri, Tandra R.; Szafran, April Adams; O’Quinn, Darrell; Weaver, Casey; Dugger, Kari; Lamar, Dale; Kesterson, Robert A.; Wang, Xiangdong; Frank, Stuart J.

    2008-01-01

    There has been a rapid growth of bioluminescence imaging applications in small animal models in recent years, propelled by the availability of instruments, analysis software, reagents, and creative approaches to apply the technology in molecular imaging. Advantages include the sensitivity of the technique as well as its efficiency, relatively low cost, and versatility. Bioluminescence imaging is accomplished by sensitive detection of light emitted following chemical reaction of the luciferase...

  9. Circadian Control Sheds Light on Fungal Bioluminescence

    OpenAIRE

    Oliveira, Anderson G.; Cassius V. Stevani; Waldenmaier, Hans E.; Viviani, Vadim; Emerson, Jillian M.; Loros, Jennifer J.; Jay C Dunlap

    2015-01-01

    Bioluminescence, the creation and emission of light by organisms, affords insight into the lives of organisms doing it. Luminous living things are widespread and access diverse mechanisms to generate and control luminescence [1-5]. Among the least studied bioluminescent organisms are phylogenetically rare fungi – only 71 species, all within the ~9000 fungi of the temperate and tropical Agaricales Order - are reported from among ~100,000 described fungal species [6,7]. All require oxygen [8] a...

  10. Development of a new procedure based on the energy charge measurement using ATP bioluminescence assay for the detection of living mould from graphic documents.

    Science.gov (United States)

    Rakotonirainy, Malalanirina Sylvia; Arnold, Sylvia

    2008-01-01

    Fungal contamination is a major cause of deterioration in libraries and archives. Curators and conservators increasingly need rapid microbiological analyses. This paper presents a rapid detection method for the fungal contaminants on documents. A previous study showed that the calculation of energy charge, using bioluminescence ATP assays, provides a useful indicator to determinate the viability of fungal strains. We argue that this sensitive and time-saving method is better than traditional culture techniques. However, the procedure needs to be modified to make it usable for lay persons. An improved and simplified protocol is proposed here for the extraction of adenylate nucleotides (AN) from fungal spores and for their measurements. Our new procedure can detect the existence of viable fungal strains on documents, presenting suspect spots within minutes. The extraction is performed by filtration with DMSO-TE solution as extractant. The different step of the measurement of AN content is carried out successively in a single test tube instead of the three tubes necessary in the initial method. The new procedure was tested on 12 strains among those most frequently found in archives and libraries and validated on swab samples from real documents.

  11. High resolution imaging with impulse based thermoacoustic tomography

    Science.gov (United States)

    Kellnberger, Stephan; Hajiaboli, Amir; Sergiadis, George; Razansky, Daniel; Ntziachristos, Vasilis

    2011-07-01

    Existing imaging modalities like microwave- or radiofrequency (RF) induced thermoacoustic tomography systems show the potential for resolving structures deep inside tissue due to the high penetration properties of RF. However, one of the major drawbacks of existing thermoacoustic tomography systems with pulse modulated carrier frequency excitation is the compromise between efficient signal generation and attainable spatial resolution. In order to overcome limitations of conventional thermoacoustic imaging methods, we herein present and experimentally validate our novel approach towards high resolution thermoacoustic tomography. Instead of carrier-frequency amplification, we utilize ultrahigh-energy electromagnetic impulses at nanosecond duration with near-field energy coupling, thus maintaining thermoacoustic signal strength without compromising spatial resolution. Preliminary experiments on highly absorbing objects, consisting of copper wires with characteristic sizes of ~100 μm, reveal the resolution performance which yields 160 μm. Furthermore, benefits like its cost effectiveness, simplicity and compactness with the potential application in small animal imaging as well as human body imaging show that thermoacoustic tomography with impulse excitation is a promising imaging modality which has a broad range of applications.

  12. The Repetitive Detection of Toluene with Bioluminescence Bioreporter Pseudomonas putida TVA8 Encapsulated in Silica Hydrogel on an Optical Fiber

    Directory of Open Access Journals (Sweden)

    Gabriela Kuncová

    2016-06-01

    Full Text Available Living cells of the lux-based bioluminescent bioreporter Pseudomonas putida TVA8 were encapsulated in a silica hydrogel attached to the distal wider end of a tapered quartz fiber. Bioluminescence of immobilized cells was induced with toluene at high (26.5 mg/L and low (5.3 mg/L concentrations. Initial bioluminescence maxima were achieved after >12 h. One week after immobilization, a biofilm-like layer of cells had formed on the surface of the silica gel. This resulted in shorter response times and more intensive bioluminescence maxima that appeared as rapidly as 2 h after toluene induction. Considerable second bioluminescence maxima were observed after inductions with 26.5 mg toluene/L. The second and third week after immobilization the biosensor repetitively and semiquantitatively detected toluene in buffered medium. Due to silica gel dissolution and biofilm detachment, the bioluminescent signal was decreasing 20–32 days after immobilization and completely extinguished after 32 days. The reproducible formation of a surface cell layer on the wider end of the tapered optical fiber can be translated to various whole cell bioluminescent biosensor devices and may serve as a platform for in-situ sensors.

  13. Multi-Resolution Seismic Tomography Based on Recursive Tessellation Hierarchy

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, N A; Myers, S C; Ramirez, A

    2009-07-01

    A 3-D global tomographic model that reconstructs velocity structure at multiple scales and incorporates laterally variable seismic discontinuities is currently being developed. The model parameterization is node-based where nodes are placed along vertices defined by triangular tessellations of a spheroidal surface. The triangular tessellation framework is hierarchical. Starting with a tetrahexahedron representing the whole globe (1st level of the hierarchy, 24 faces), they divide each triangle of the tessellation into daughter triangles. The collection of all daughter triangles comprises the 2nd level of the tessellation hierarchy and further recursion produces an arbitrary number of tessellation levels and arbitrarily fine node-spacing. They have developed an inversion procedure that takes advantage of the recursive properties of the tessellation hierarchies by progressively solving for shorter wavelength heterogeneities. In this procedure, we first perform the tomographic inversion using a tessellation level with coarse node spacing. They find that a coarse node spacing of approximately 8{sup o} is adequate to capture bulk regional properties. They then conduct the tomographic inversion on a 4{sup o} tessellation level using the residuals and inversion results from the 8{sup o} run. In practice they find that the progressive tomography approach is robust, providing an intrinsic regularization for inversion stability and avoids the issue of predefining resolution levels. Further, determining average regional properties with coarser tessellation levels enables long-wavelength heterogeneities to account for sparsely sampled regions (or regions of the mantle where longer wavelength patterns of heterogeneity suffice) while allowing shorter length-scale heterogeneities to emerge where necessary. They demonstrate the inversion approach with a set of synthetic test cases that mimic the complex nature of data arrangements (mixed-determined inversion) common to most

  14. Lung Ventilation Functional Monitoring Based on Electrical Impedance Tomography

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiaoyan; WANG Huaxiang; ZHAO Bo; SHI Xiaolei

    2009-01-01

    Medically,electrical impedance tomography(EIT)is a relatively inexpensive,safe,non-invasive and portable technique compared with computerized tomography(CT)and magnetic resonance imaging(MRI).In this paper,EIT_TJU_Ⅱ system is developed including both the data collection system and image reconstruction algorithm.The testing approach of the system performance,including spatial resolution and sensitivity,is described through brine tank experiments.The images of the thorax physical model verify that the system can reconstruct the interior resistivity distribution.Finally,the lung ventilation functional monitoring in vivo is realized by EIT,and the visualized images indicate that the configuration and performance of EIT_TJU_Ⅱ system are feasible and EIT is a promising technique in clinical monitoring application.

  15. Noninvasive bioluminescence imaging in small animals.

    Science.gov (United States)

    Zinn, Kurt R; Chaudhuri, Tandra R; Szafran, April Adams; O'Quinn, Darrell; Weaver, Casey; Dugger, Kari; Lamar, Dale; Kesterson, Robert A; Wang, Xiangdong; Frank, Stuart J

    2008-01-01

    There has been a rapid growth of bioluminescence imaging applications in small animal models in recent years, propelled by the availability of instruments, analysis software, reagents, and creative approaches to apply the technology in molecular imaging. Advantages include the sensitivity of the technique as well as its efficiency, relatively low cost, and versatility. Bioluminescence imaging is accomplished by sensitive detection of light emitted following chemical reaction of the luciferase enzyme with its substrate. Most imaging systems provide 2-dimensional (2D) information in rodents, showing the locations and intensity of light emitted from the animal in pseudo-color scaling. A 3-dimensional (3D) capability for bioluminescence imaging is now available, but is more expensive and less efficient; other disadvantages include the requirement for genetically encoded luciferase, the injection of the substrate to enable light emission, and the dependence of light signal on tissue depth. All of these problems make it unlikely that the method will be extended to human studies. However, in small animal models, bioluminescence imaging is now routinely applied to serially detect the location and burden of xenografted tumors, or identify and measure the number of immune or stem cells after an adoptive transfer. Bioluminescence imaging also makes it possible to track the relative amounts and locations of bacteria, viruses, and other pathogens over time. Specialized applications of bioluminescence also follow tissue-specific luciferase expression in transgenic mice, and monitor biological processes such as signaling or protein interactions in real time. In summary, bioluminescence imaging has become an important component of biomedical research that will continue in the future.

  16. Optical coherence tomography-based micro-particle image velocimetry.

    Science.gov (United States)

    Mujat, Mircea; Ferguson, R Daniel; Iftimia, Nicusor; Hammer, Daniel X; Nedyalkov, Ivaylo; Wosnik, Martin; Legner, Hartmut

    2013-11-15

    We present a new application of optical coherence tomography (OCT), widely used in biomedical imaging, to flow analysis in near-wall hydrodynamics for marine research. This unique capability, called OCT micro-particle image velocimetry, provides a high-resolution view of microscopic flow phenomena and measurement of flow statistics within the first millimeter of a boundary layer. The technique is demonstrated in a small flow cuvette and in a water tunnel.

  17. Line-Source Based X-Ray Tomography

    OpenAIRE

    Deepak Bharkhada; Hengyong Yu; Hong Liu; Robert Plemmons; Ge Wang

    2009-01-01

    Current computed tomography (CT) scanners, including micro-CT scanners, utilize a point x-ray source. As we target higher and higher spatial resolutions, the reduced x-ray focal spot size limits the temporal and contrast resolutions achievable. To overcome this limitation, in this paper we propose to use a line-shaped x-ray source so that many more photons can be generated, given a data acquisition interval. In reference to the simultaneous algebraic reconstruction technique (SART) algorithm ...

  18. NanoLuc: A Small Luciferase Is Brightening Up the Field of Bioluminescence.

    Science.gov (United States)

    England, Christopher G; Ehlerding, Emily B; Cai, Weibo

    2016-05-18

    The biomedical field has greatly benefited from the discovery of bioluminescent proteins. Currently, scientists employ bioluminescent systems for numerous biomedical applications, ranging from highly sensitive cellular assays to bioluminescence-based molecular imaging. Traditionally, these systems are based on Firefly and Renilla luciferases; however, the applicability of these enzymes is limited by their size, stability, and luminescence efficiency. NanoLuc (NLuc), a novel bioluminescence platform, offers several advantages over established systems, including enhanced stability, smaller size, and >150-fold increase in luminescence. In addition, the substrate for NLuc displays enhanced stability and lower background activity, opening up new possibilities in the field of bioluminescence imaging. The NLuc system is incredibly versatile and may be utilized for a wide array of applications. The increased sensitivity, high stability, and small size of the NLuc system have the potential to drastically change the field of reporter assays in the future. However, as with all such technology, NLuc has limitations (including a nonideal emission for in vivo applications and its unique substrate) which may cause it to find restricted use in certain areas of molecular biology. As this unique technology continues to broaden, NLuc may have a significant impact in both preclinical and clinical fields, with potential roles in disease detection, molecular imaging, and therapeutic monitoring. This review will present the NLuc technology to the scientific community in a nonbiased manner, allowing the audience to adopt their own views of this novel system. PMID:27045664

  19. NanoLuc: A Small Luciferase Is Brightening Up the Field of Bioluminescence.

    Science.gov (United States)

    England, Christopher G; Ehlerding, Emily B; Cai, Weibo

    2016-05-18

    The biomedical field has greatly benefited from the discovery of bioluminescent proteins. Currently, scientists employ bioluminescent systems for numerous biomedical applications, ranging from highly sensitive cellular assays to bioluminescence-based molecular imaging. Traditionally, these systems are based on Firefly and Renilla luciferases; however, the applicability of these enzymes is limited by their size, stability, and luminescence efficiency. NanoLuc (NLuc), a novel bioluminescence platform, offers several advantages over established systems, including enhanced stability, smaller size, and >150-fold increase in luminescence. In addition, the substrate for NLuc displays enhanced stability and lower background activity, opening up new possibilities in the field of bioluminescence imaging. The NLuc system is incredibly versatile and may be utilized for a wide array of applications. The increased sensitivity, high stability, and small size of the NLuc system have the potential to drastically change the field of reporter assays in the future. However, as with all such technology, NLuc has limitations (including a nonideal emission for in vivo applications and its unique substrate) which may cause it to find restricted use in certain areas of molecular biology. As this unique technology continues to broaden, NLuc may have a significant impact in both preclinical and clinical fields, with potential roles in disease detection, molecular imaging, and therapeutic monitoring. This review will present the NLuc technology to the scientific community in a nonbiased manner, allowing the audience to adopt their own views of this novel system.

  20. Bioluminescence microscopy using a short focal-length imaging lens

    OpenAIRE

    Ogoh, K; Akiyoshi, R; May-Maw-Thet,; Sugiyama, T; Dosaka, S; Hatta-Ohashi, Y; Suzuki, H.

    2014-01-01

    Bioluminescence from cells is so dim that bioluminescence microscopy is performed using an ultra low-light imaging camera. Although the image sensor of such cameras has been greatly improved over time, such improvements have not been made commercially available for microscopes until now. Here, we customized the optical system of a microscope for bioluminescence imaging. As a result, bioluminescence images of cells could be captured with a conventional objective lens and colour imaging camera....

  1. Bacteria bioluminescent activity as an indicator of geomagnetic disturbances

    International Nuclear Information System (INIS)

    The effect of geomagnetic disturbances and storms on bioluminescence activity of bacterium were investigated. The bioluminescence intensity change depended on amplitude and continuous of geomagnetic storms. It is assumed, that the synchronization of luminous radiation take place in cellos when frequency of geomagnetic disturbances approached to an intrinsic one of a bioluminescence system. High sensitivity of bioluminescence of geomagnetic storms was detected. 5 refs., 4 figs

  2. Fluorescence and bioluminescence of bacterial luciferase intermediates

    International Nuclear Information System (INIS)

    An intermediate in the luciferase-catalyzed bioluminescent oxidation of FMNH2, isolated and purified by chromatography at --200, was postulated to be an oxygenated reduced flavine-luciferase. Maintained and studied at --20 to --300, this material exhibits a relatively weak fluorescence emission peaking at about 505 nm when excited at 370 nm. It may comprise more than one species. Upon continued exposure to light at 370 nm, the intensity of this fluorescence increases, often by a factor of 5 or more, and its emission spectrum is blue shifted to a maximum at about 485 nm. Upon warming this fluorescence is lost and the fluorescence of flavine mononucleotide appears. If warming is carried out in the presence of a long chain aldehyde, bioluminescence occurs, with the appearance of a similar amount of flavine fluorescence. The bioluminescence yield is about the same with irradiated and nonirradiated samples. The bioluminescence emission spectrum corresponds exactly to the fluorescence emission spectrum of the intermediate formed by irradiation, implicating the latter as being structurally close to the emitting species in bioluminescence. (auth)

  3. Fluorescent and Bioluminescent Reporter Myxoviruses

    Science.gov (United States)

    Rostad, Christina A.; Currier, Michael C.; Moore, Martin L.

    2016-01-01

    The advent of virus reverse genetics has enabled the incorporation of genetically encoded reporter proteins into replication-competent viruses. These reporters include fluorescent proteins which have intrinsic chromophores that absorb light and re-emit it at lower wavelengths, and bioluminescent proteins which are luciferase enzymes that react with substrates to produce visible light. The incorporation of these reporters into replication-competent viruses has revolutionized our understanding of molecular virology and aspects of viral tropism and transmission. Reporter viruses have also enabled the development of high-throughput assays to screen antiviral compounds and antibodies and to perform neutralization assays. However, there remain technical challenges with the design of replication-competent reporter viruses, and each reporter has unique advantages and disadvantages for specific applications. This review describes currently available reporters, design strategies for incorporating reporters into replication-competent paramyxoviruses and orthomyxoviruses, and the variety of applications for which these tools can be utilized both in vitro and in vivo. PMID:27527209

  4. Fluorescent and Bioluminescent Reporter Myxoviruses.

    Science.gov (United States)

    Rostad, Christina A; Currier, Michael C; Moore, Martin L

    2016-01-01

    The advent of virus reverse genetics has enabled the incorporation of genetically encoded reporter proteins into replication-competent viruses. These reporters include fluorescent proteins which have intrinsic chromophores that absorb light and re-emit it at lower wavelengths, and bioluminescent proteins which are luciferase enzymes that react with substrates to produce visible light. The incorporation of these reporters into replication-competent viruses has revolutionized our understanding of molecular virology and aspects of viral tropism and transmission. Reporter viruses have also enabled the development of high-throughput assays to screen antiviral compounds and antibodies and to perform neutralization assays. However, there remain technical challenges with the design of replication-competent reporter viruses, and each reporter has unique advantages and disadvantages for specific applications. This review describes currently available reporters, design strategies for incorporating reporters into replication-competent paramyxoviruses and orthomyxoviruses, and the variety of applications for which these tools can be utilized both in vitro and in vivo. PMID:27527209

  5. Discovery of New Substrates for LuxAB Bacterial Bioluminescence.

    Science.gov (United States)

    Jiang, Tianyu; Wang, Weishan; Wu, Xingkang; Wu, Wenxiao; Bai, Haixiu; Ma, Zhao; Shen, Yuemao; Yang, Keqian; Li, Minyong

    2016-08-01

    In this article, four novel substrates with long halftime have been designed and synthesized successfully for luxAB bacterial bioluminescence. After in vitro and in vivo biological evaluation, these molecules can emit obvious bioluminescence emission with known bacterial luciferase, thus indicating a new promising approach to developing the bacterial bioluminescent system. PMID:26896339

  6. Discovery of New Substrates for LuxAB Bacterial Bioluminescence.

    Science.gov (United States)

    Jiang, Tianyu; Wang, Weishan; Wu, Xingkang; Wu, Wenxiao; Bai, Haixiu; Ma, Zhao; Shen, Yuemao; Yang, Keqian; Li, Minyong

    2016-08-01

    In this article, four novel substrates with long halftime have been designed and synthesized successfully for luxAB bacterial bioluminescence. After in vitro and in vivo biological evaluation, these molecules can emit obvious bioluminescence emission with known bacterial luciferase, thus indicating a new promising approach to developing the bacterial bioluminescent system.

  7. Bioluminescent bioreporter assays for targeted detection of chemical and biological agents

    Science.gov (United States)

    Ripp, Steven; Jegier, Pat; Johnson, Courtney; Moser, Scott; Islam, Syed; Sayler, Gary

    2008-04-01

    Bioluminescent bioreporters carrying the bacterial lux gene cassette have been well established for the sensing and monitoring of select chemical agents. Their ability to generate target specific visible light signals with no requirement for extraneous additions of substrate or other hands-on manipulations affords a real-time, repetitive assaying technique that is remarkable in its simplicity and accuracy. Although the predominant application of lux-based bioluminescent bioreporters has been towards chemical compound detection, novel genetic engineering schemes are yielding a variety of new bioreporter systems that extend the lux sensing mechanism beyond mere analyte discrimination. For example, the unique specificity of bacteriophage (bacterial viruses) has been exploited in lux bioluminescent assays for specific identification of foodborne bacterial pathogens such as Escherichia coli O157:H7. With the concurrent ability to interface bioluminescent bioreporter assays onto integrated circuit microluminometers (BBICs; bioluminescent bioreporter integrated circuits), the potential exists for the development of sentinel microchips that can function as environmental monitors for multiplexed recognition of chemical and biological agents in air, food, and water. The size and portability of BBIC biosensors may ultimately provide a deployable, interactive network sensing technology adaptable towards chem/bio defense.

  8. High-throughput and quantitative approaches for measuring circadian rhythms in cyanobacteria using bioluminescence.

    Science.gov (United States)

    Shultzaberger, Ryan K; Paddock, Mark L; Katsuki, Takeo; Greenspan, Ralph J; Golden, Susan S

    2015-01-01

    The temporal measurement of a bioluminescent reporter has proven to be one of the most powerful tools for characterizing circadian rhythms in the cyanobacterium Synechococcus elongatus. Primarily, two approaches have been used to automate this process: (1) detection of cell culture bioluminescence in 96-well plates by a photomultiplier tube-based plate-cycling luminometer (TopCount Microplate Scintillation and Luminescence Counter, Perkin Elmer) and (2) detection of individual colony bioluminescence by iteratively rotating a Petri dish under a cooled CCD camera using a computer-controlled turntable. Each approach has distinct advantages. The TopCount provides a more quantitative measurement of bioluminescence, enabling the direct comparison of clock output levels among strains. The computer-controlled turntable approach has a shorter set-up time and greater throughput, making it a more powerful phenotypic screening tool. While the latter approach is extremely useful, only a few labs have been able to build such an apparatus because of technical hurdles involved in coordinating and controlling both the camera and the turntable, and in processing the resulting images. This protocol provides instructions on how to construct, use, and process data from a computer-controlled turntable to measure the temporal changes in bioluminescence of individual cyanobacterial colonies. Furthermore, we describe how to prepare samples for use with the TopCount to minimize experimental noise and generate meaningful quantitative measurements of clock output levels for advanced analysis.

  9. High throughput and quantitative approaches for measuring circadian rhythms in cyanobacteria using bioluminescence

    Science.gov (United States)

    Shultzaberger, Ryan K.; Paddock, Mark L.; Katsuki, Takeo; Greenspan, Ralph J.; Golden, Susan S.

    2016-01-01

    The temporal measurement of a bioluminescent reporter has proven to be one of the most powerful tools for characterizing circadian rhythms in the cyanobacterium Synechococcus elongatus. Primarily, two approaches have been used to automate this process: (1) detection of cell culture bioluminescence in 96-well plates by a photomultiplier tube-based plate-cycling luminometer (TopCount Microplate Scintillation and Luminescence Counter, Perkin Elmer) and (2) detection of individual colony bioluminescence by iteratively rotating a Petri dish under a cooled CCD camera using a computer-controlled turntable. Each approach has distinct advantages. The TopCount provides a more quantitative measurement of bioluminescence, enabling the direct comparison of clock output levels among strains. The computer-controlled turntable approach has a shorter set-up time and greater throughput, making it a more powerful phenotypic screening tool. While the latter approach is extremely useful, only a few labs have been able to build such an apparatus because of technical hurdles involved in coordinating and controlling both the camera and the turntable, and in processing the resulting images. This protocol provides instructions on how to construct, use, and process data from a computer-controlled turntable to measure the temporal changes in bioluminescence of individual cyanobacterial colonies. Furthermore, we describe how to prepare samples for use with the TopCount to minimize experimental noise, and generate meaningful quantitative measurements of clock output levels for advanced analysis. PMID:25662451

  10. High-throughput and quantitative approaches for measuring circadian rhythms in cyanobacteria using bioluminescence.

    Science.gov (United States)

    Shultzaberger, Ryan K; Paddock, Mark L; Katsuki, Takeo; Greenspan, Ralph J; Golden, Susan S

    2015-01-01

    The temporal measurement of a bioluminescent reporter has proven to be one of the most powerful tools for characterizing circadian rhythms in the cyanobacterium Synechococcus elongatus. Primarily, two approaches have been used to automate this process: (1) detection of cell culture bioluminescence in 96-well plates by a photomultiplier tube-based plate-cycling luminometer (TopCount Microplate Scintillation and Luminescence Counter, Perkin Elmer) and (2) detection of individual colony bioluminescence by iteratively rotating a Petri dish under a cooled CCD camera using a computer-controlled turntable. Each approach has distinct advantages. The TopCount provides a more quantitative measurement of bioluminescence, enabling the direct comparison of clock output levels among strains. The computer-controlled turntable approach has a shorter set-up time and greater throughput, making it a more powerful phenotypic screening tool. While the latter approach is extremely useful, only a few labs have been able to build such an apparatus because of technical hurdles involved in coordinating and controlling both the camera and the turntable, and in processing the resulting images. This protocol provides instructions on how to construct, use, and process data from a computer-controlled turntable to measure the temporal changes in bioluminescence of individual cyanobacterial colonies. Furthermore, we describe how to prepare samples for use with the TopCount to minimize experimental noise and generate meaningful quantitative measurements of clock output levels for advanced analysis. PMID:25662451

  11. Development of bioluminescent bioreporters for in vitro and in vivo tracking of Yersinia pestis.

    Directory of Open Access Journals (Sweden)

    Yanwen Sun

    Full Text Available Yersinia pestis causes an acute infection known as the plague. Conventional techniques to enumerate Y. pestis can be labor intensive and do not lend themselves to high throughput assays. In contrast, bioluminescent bioreporters produce light that can be detected using plate readers or optical imaging platforms to monitor bacterial populations as a function of luminescence. Here, we describe the development of two Y. pestis chromosomal-based luxCDABE bioreporters, Lux(PtolC and Lux(PcysZK. These bioreporters use constitutive promoters to drive expression of luxCDABE that allow for sensitive detection of bacteria via bioluminescence in vitro. Importantly, both bioreporters demonstrate a direct correlation between bacterial numbers and bioluminescence, which allows for bioluminescence to be used to compare bacterial numbers. We demonstrate the use of these bioreporters to test antimicrobial inhibitors (Lux(PtolC and monitor intracellular survival (Lux(PtolC and Lux(PcysZK in vitro. Furthermore, we show that Y. pestis infection of the mouse model can be monitored using whole animal optical imaging in real time. Using optical imaging, we observed Y. pestis dissemination and differentiated between virulence phenotypes in live animals via bioluminescence. Finally, we demonstrate that whole animal optical imaging can identify unexpected colonization patterns in mutant-infected animals.

  12. Detection of bacteria with bioluminescent reporter bacteriophage.

    Science.gov (United States)

    Klumpp, Jochen; Loessner, Martin J

    2014-01-01

    Bacteriophages are viruses that exclusively infect bacteria. They are ideally suited for the development of highly specific diagnostic assay systems. Bioluminescent reporter bacteriophages are designed and constructed by integration of a luciferase gene in the virus genome. Relying on the host specificity of the phage, the system enables rapid, sensitive, and specific detection of bacterial pathogens. A bioluminescent reporter phage assay is superior to any other molecular detection method, because gene expression and light emission are dependent on an active metabolism of the bacterial cell, and only viable cells will yield a signal. In this chapter we introduce the concept of creating reporter phages, discuss their advantages and disadvantages, and illustrate the advances made in developing such systems for different Gram-negative and Gram-positive pathogens. The application of bioluminescent reporter phages for the detection of foodborne pathogens is emphasized.

  13. In vivo cell tracking with bioluminescence imaging.

    Science.gov (United States)

    Kim, Jung Eun; Kalimuthu, Senthilkumar; Ahn, Byeong-Cheol

    2015-03-01

    Molecular imaging is a fast growing biomedical research that allows the visual representation, characterization and quantification of biological processes at the cellular and subcellular levels within intact living organisms. In vivo tracking of cells is an indispensable technology for development and optimization of cell therapy for replacement or renewal of damaged or diseased tissue using transplanted cells, often autologous cells. With outstanding advantages of bioluminescence imaging, the imaging approach is most commonly applied for in vivo monitoring of transplanted stem cells or immune cells in order to assess viability of administered cells with therapeutic efficacy in preclinical small animal models. In this review, a general overview of bioluminescence is provided and recent updates of in vivo cell tracking using the bioluminescence signal are discussed.

  14. In vivo cell tracking with bioluminescence imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Eun; Kalimuthu, Senthilkumar; Ahn, Byeong Cheol [Dept. of Nuclear Medicine, Kyungpook National University School of Medicine and Hospital, Daegu (Korea, Republic of)

    2015-03-15

    Molecular imaging is a fast growing biomedical research that allows the visual representation, characterization and quantification of biological processes at the cellular and subcellular levels within intact living organisms. In vivo tracking of cells is an indispensable technology for development and optimization of cell therapy for replacement or renewal of damaged or diseased tissue using transplanted cells, often autologous cells. With outstanding advantages of bioluminescence imaging, the imaging approach is most commonly applied for in vivo monitoring of transplanted stem cells or immune cells in order to assess viability of administered cells with therapeutic efficacy in preclinical small animal models. In this review, a general overview of bioluminescence is provided and recent updates of in vivo cell tracking using the bioluminescence signal are discussed.

  15. In vivo cell tracking with bioluminescence imaging

    International Nuclear Information System (INIS)

    Molecular imaging is a fast growing biomedical research that allows the visual representation, characterization and quantification of biological processes at the cellular and subcellular levels within intact living organisms. In vivo tracking of cells is an indispensable technology for development and optimization of cell therapy for replacement or renewal of damaged or diseased tissue using transplanted cells, often autologous cells. With outstanding advantages of bioluminescence imaging, the imaging approach is most commonly applied for in vivo monitoring of transplanted stem cells or immune cells in order to assess viability of administered cells with therapeutic efficacy in preclinical small animal models. In this review, a general overview of bioluminescence is provided and recent updates of in vivo cell tracking using the bioluminescence signal are discussed

  16. A Multichannel Bioluminescence Determination Platform for Bioassays.

    Science.gov (United States)

    Kim, Sung-Bae; Naganawa, Ryuichi

    2016-01-01

    The present protocol introduces a multichannel bioluminescence determination platform allowing a high sample throughput determination of weak bioluminescence with reduced standard deviations. The platform is designed to carry a multichannel conveyer, an optical filter, and a mirror cap. The platform enables us to near-simultaneously determine ligands in multiple samples without the replacement of the sample tubes. Furthermore, the optical filters beneath the multichannel conveyer are designed to easily discriminate colors during assays. This optical system provides excellent time- and labor-efficiency to users during bioassays.

  17. A Multichannel Bioluminescence Determination Platform for Bioassays.

    Science.gov (United States)

    Kim, Sung-Bae; Naganawa, Ryuichi

    2016-01-01

    The present protocol introduces a multichannel bioluminescence determination platform allowing a high sample throughput determination of weak bioluminescence with reduced standard deviations. The platform is designed to carry a multichannel conveyer, an optical filter, and a mirror cap. The platform enables us to near-simultaneously determine ligands in multiple samples without the replacement of the sample tubes. Furthermore, the optical filters beneath the multichannel conveyer are designed to easily discriminate colors during assays. This optical system provides excellent time- and labor-efficiency to users during bioassays. PMID:27424912

  18. Chemistry and biology of insect bioluminescence

    International Nuclear Information System (INIS)

    Basic aspects on the Chemistry and Biology of bioluminescence are reviewed, with emphasis on insects. Data from the investigation of Lampyridae (fireflies) are collected from literature. With regard to Elateridae (click beetles) and Phengodidae (rail road worms), the least explored families of luminescent insects, new data are presented on the following aspects: (i) 'in vivo' emission spectra, (ii) chemical nature of the luciferin, (iii) conection between bioluminescence and 'oxygen toxicity' as a result of molecular oxygen storage and (iv) the role of light emission by larvae and pupae. (Author)

  19. Theoretical tuning of the firefly bioluminescence spectra by the modification of oxyluciferin

    Science.gov (United States)

    Cheng, Yuan-Yuan; Zhu, Jia; Liu, Ya-Jun

    2014-01-01

    Extending the firefly bioluminescence is of practical significance for the improved visualization of living cells and the development of a multicolor reporter. Tuning the color of bioluminescence in fireflies mainly involves the modification of luciferase and luciferin. In this Letter, we theoretically studied the emission spectra of 9 firefly oxyluciferin analogs in the gas phase and in solutions. Three density functionals, including B3LYP, CAM-B3LYP and M06-2X, were employed to theoretically predict the efficiently luminescent analogs. The reliable functionals for calculating the targeted systems were suggested. The luminescence efficiency, solvent effects, and substituent effects are discussed based on the calculated results.

  20. Bioluminescence for determining energy state of plants

    Science.gov (United States)

    Ching, T. M.

    1975-01-01

    Bioluminescence produced by the luciferin-luciferase system is a very sensitive assay for ATP content in extracts of plant materials. The ATP test for seed and pollen viability and vigor is presented, along with prediction of high growth potential and productivity in new crosses and selections of breeding materials. ATP as an indicator for environmental quality, stresses, and metabolic regulation is also considered.

  1. Multicolor Bioluminescence Obtained Using Firefly Luciferin.

    Science.gov (United States)

    Kiyama, Masahiro; Saito, Ryohei; Iwano, Satoshi; Obata, Rika; Niwa, Haruki; Maki, Shojiro A

    2016-01-01

    Firefly bioluminescence is widely used in life science research as a useful analysis tool. For example, the adenosine-5`-triphosphate (ATP)-dependent enzymatic firefly bioluminescence reaction has long been utilized as a microbial monitoring tool. Rapid and sensitive firefly luciferin-luciferase combinations are used not only to measure cell viability but also for reporter-gene assays. Recently, bioluminescence was utilized as a noninvasive, real-time imaging tool for living subjects to monitor cells and biological events. However, the number of commercialized luciferase genes is limited and tissue-permeable near-infrared (NIR) region emitting light is required for in vivo imaging. In this review, recent studies describing synthetic luciferin analogues predicted to have red-shifted bioluminescence are summarized. Luciferase substrates emitting red, green, and blue light that were designed and developed in our laboratory are presented. The longest emission wavelength of the synthesized luciferin analogues was recorded at 675 nm, which is within the NIR region. This compound is now commercially available as "Aka Lumine®".

  2. Bioluminescence: diplôme 2015

    OpenAIRE

    Giachino, Vincent; Geiser, Martial

    2016-01-01

    Dans le cadre du projet européen BRAAVOO, qui vise à mesurer les concentrations de différents polluants présents dans la mer, nous développons un lecteur de bioluminescence embarqué dans une bouée.

  3. Bioluminescent bioreporter integrated circuit detection methods

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Michael L.; Paulus, Michael J.; Sayler, Gary S.; Applegate, Bruce M.; Ripp, Steven A.

    2005-06-14

    Disclosed are monolithic bioelectronic devices comprising a bioreporter and an OASIC. These bioluminescent bioreporter integrated circuit are useful in detecting substances such as pollutants, explosives, and heavy-metals residing in inhospitable areas such as groundwater, industrial process vessels, and battlefields. Also disclosed are methods and apparatus for detection of particular analytes, including ammonia and estrogen compounds.

  4. Amplitude metrics for cellular circadian bioluminescence reporters.

    Science.gov (United States)

    St John, Peter C; Taylor, Stephanie R; Abel, John H; Doyle, Francis J

    2014-12-01

    Bioluminescence rhythms from cellular reporters have become the most common method used to quantify oscillations in circadian gene expression. These experimental systems can reveal phase and amplitude change resulting from circadian disturbances, and can be used in conjunction with mathematical models to lend further insight into the mechanistic basis of clock amplitude regulation. However, bioluminescence experiments track the mean output from thousands of noisy, uncoupled oscillators, obscuring the direct effect of a given stimulus on the genetic regulatory network. In many cases, it is unclear whether changes in amplitude are due to individual changes in gene expression level or to a change in coherence of the population. Although such systems can be modeled using explicit stochastic simulations, these models are computationally cumbersome and limit analytical insight into the mechanisms of amplitude change. We therefore develop theoretical and computational tools to approximate the mean expression level in large populations of noninteracting oscillators, and further define computationally efficient amplitude response calculations to describe phase-dependent amplitude change. At the single-cell level, a mechanistic nonlinear ordinary differential equation model is used to calculate the transient response of each cell to a perturbation, whereas population-level dynamics are captured by coupling this detailed model to a phase density function. Our analysis reveals that amplitude changes mediated at either the individual-cell or the population level can be distinguished in tissue-level bioluminescence data without the need for single-cell measurements. We demonstrate the effectiveness of the method by modeling experimental bioluminescence profiles of light-sensitive fibroblasts, reconciling the conclusions of two seemingly contradictory studies. This modeling framework allows a direct comparison between in vitro bioluminescence experiments and in silico ordinary

  5. A computed tomography reconstruction algorithm based on multipurpose optimal criterion and simulated annealing theory

    Institute of Scientific and Technical Information of China (English)

    Hui Li; Xiong Wan; Taoli Liu; Zhongshou Liu; Yanhua Zhu

    2007-01-01

    Although emission spectral tomography (EST) combines emission spectral measurement with optical computed tomography (OCT), it is difficult to gain transient emission data from a large number of views,therefore, high precision OCT algorithms with few views ought to be studied for EST application. To improve the reconstruction precision in the case of few views, a new computed tomography reconstruction algorithm based on multipurpose optimal criterion and simulated annealing theory (multi-criterion simulated annealing reconstruction technique, MCSART) is proposed. This algorithm can suffice criterion of least squares, criterion of most uniformity, and criterion of most smoothness synchronously. We can get global optimal solution by MCSART algorithm with simulated annealing theory. The simulating experiment result shows that this algorithm is superior to the traditional algorithms under various noises.

  6. Registration-based Reconstruction of Four-dimensional Cone Beam Computed Tomography

    DEFF Research Database (Denmark)

    Christoffersen, Christian; Hansen, David Christoffer; Poulsen, Per Rugaard;

    2013-01-01

    We present a new method for reconstruction of four-dimensional (4D) cone beam computed tomography from an undersampled set of X-ray projections. The novelty of the proposed method lies in utilizing optical flow based registration to facilitate that each temporal phase is reconstructed from the full...

  7. Simulation-Based Planning of Optimal Conditions for Industrial Computed Tomography

    DEFF Research Database (Denmark)

    Reisinger, S.; Kasperl, S.; Franz, M.;

    2011-01-01

    We present a method to optimise conditions for industrial computed tomography (CT). This optimisation is based on a deterministic simulation. Our algorithm finds task-specific CT equipment settings to achieve optimal exposure parameters by means of an STL-model of the specimen and a raytracing...

  8. Contextual Multivariate Segmentation of Pork Tissue from Grating-Based Multimodal X-Ray Tomography

    DEFF Research Database (Denmark)

    Einarsdottir, Hildur; Nielsen, Mikkel S.; Ersbøll, Bjarne Kjær;

    2013-01-01

    X-ray computed tomography is increasingly used as a nondestructive method for studying three dimensional food structures. For meat products, studies have focused mainly on fat and protein content due to limited contrast capabilities of absorption based techniques. Recent advances in X-ray imaging...

  9. Activity-based costing evaluation of a [F-18]-fludeoxyglucose positron emission tomography study

    NARCIS (Netherlands)

    Krug, Bruno; Van Zanten, Annie; Pirson, Anne-Sophie; Crott, Ralph; Vander Borght, Thierry

    2009-01-01

    Objective: The aim of the study is to use the activity-based costing approach to give a better insight in the actual cost structure of a positron emission tomography procedure (FDG-PET) by defining the constituting components and by simulating the impact of possible resource or practice changes. Met

  10. Chip Based Common-path Swept-source Optical Coherence Tomography Device

    NARCIS (Netherlands)

    Chang, Lantian

    2016-01-01

    Optical coherence tomography (OCT) is an optical imaging technique which provides three-dimensional images with micrometer-resolution. OCT has been extensively used for disease diagnostics, treatment planning, and surgical guidance. Currently, most of the OCT systems are based on discrete free-space

  11. Linear GPR Imaging Based on Electromagnetic Plane-Wave Spectra and Diffraction Tomography

    DEFF Research Database (Denmark)

    Meincke, Peter

    2004-01-01

    Two linear diffraction-tomography based inversion schemes, referred to as the Fourier transform method (FTM) and the far-field method (FFM), are derived for 3-dimensional fixed-offset GPR imaging of buried objects. The FTM and FFM are obtained by using different asymptotic approximations in the...

  12. A genetically encoded bioluminescent indicator for illuminating proinflammatory cytokines.

    Science.gov (United States)

    Kim, Sung Bae; Ozawa, Takeaki; Umezawa, Yoshio

    2016-01-01

    We introduce a method to evaluate the activities of cytokines based on the nuclear transport of NF-κB. A pair of bioluminescent indicators was made for conferring cytokine sensitivity to cervical carcinoma-derived HeLa cells. The principle is based on reconstitution of split fragments of Renilla reniformis luciferase (RLuc) by protein splicing with a DnaE intein from Synechocystis sp. PCC6803. The bioluminescence intensity of thus reconstituted RLuc in the HeLa cells was used as a measure of the activities for cytokines. With the present method, we evaluated the activities of various cytokines based on the nuclear transport of NF-κB in human cervical carcinoma-derived HeLa cells carrying the indicators. The present approach to evaluating the activities of cytokines may provide a potential clinical value in monitoring drug activity and directing treatment for various diseases related with NF-κB. The method highlights the experimental procedure from our original publications, Anal. Biochem. 2006, 359, 147-149 and Proc. Natl. Acad. Sci. U. S. A. 2004, 101, 11542. The summary of the method is: •Cytokine activities are determined within 2 h after stimulation.•Temporarily inactivated split-luciferase fragments are reconstituted by protein splicing.•Nucleartrafficking of NF-κB was illuminated for gauging the ligand-driven activity. PMID:27489781

  13. Integrated visualization of multi-angle bioluminescence imaging and micro CT

    NARCIS (Netherlands)

    Kok, P.; Dijkstra, J.; Botha, C.P.; Post, F.H.; Kaijzel, E.; Que, I.; Löwik, C.W.G.M.; Reiber, J.H.C.; Lelieveldt, B.P.F.

    2007-01-01

    This paper explores new methods to visualize and fuse multi-2D bioluminescence imaging (BLI) data with structural imaging modalities such as micro CT and MR. A geometric, back-projection-based 3D reconstruction for superficial lesions from multi-2D BLI data is presented, enabling a coarse estimate o

  14. Improved Reconstruction Quality of Bioluminescent Images by Combining SP3 Equations and Bregman Iteration Method

    Directory of Open Access Journals (Sweden)

    Qiang Wu

    2013-01-01

    Full Text Available Bioluminescence tomography (BLT has a great potential to provide a powerful tool for tumor detection, monitoring tumor therapy progress, and drug development; developing new reconstruction algorithms will advance the technique to practical applications. In the paper, we propose a BLT reconstruction algorithm by combining SP3 equations and Bregman iteration method to improve the quality of reconstructed sources. The numerical results for homogeneous and heterogeneous phantoms are very encouraging and give significant improvement over the algorithms without the use of SP3 equations and Bregman iteration method.

  15. Wide-field fluorescence molecular tomography with compressive sensing based preconditioning.

    Science.gov (United States)

    Yao, Ruoyang; Pian, Qi; Intes, Xavier

    2015-12-01

    Wide-field optical tomography based on structured light illumination and detection strategies enables efficient tomographic imaging of large tissues at very fast acquisition speeds. However, the optical inverse problem based on such instrumental approach is still ill-conditioned. Herein, we investigate the benefit of employing compressive sensing-based preconditioning to wide-field structured illumination and detection approaches. We assess the performances of Fluorescence Molecular Tomography (FMT) when using such preconditioning methods both in silico and with experimental data. Additionally, we demonstrate that such methodology could be used to select the subset of patterns that provides optimal reconstruction performances. Lastly, we compare preconditioning data collected using a normal base that offers good experimental SNR against that directly acquired with optimal designed base. An experimental phantom study is provided to validate the proposed technique.

  16. Bioluminescence microscopy using a short focal-length imaging lens.

    Science.gov (United States)

    Ogoh, K; Akiyoshi, R; May-Maw-Thet; Sugiyama, T; Dosaka, S; Hatta-Ohashi, Y; Suzuki, H

    2014-03-01

    Bioluminescence from cells is so dim that bioluminescence microscopy is performed using an ultra low-light imaging camera. Although the image sensor of such cameras has been greatly improved over time, such improvements have not been made commercially available for microscopes until now. Here, we customized the optical system of a microscope for bioluminescence imaging. As a result, bioluminescence images of cells could be captured with a conventional objective lens and colour imaging camera. As bioluminescence microscopy requires no excitation light, it lacks the photo-toxicity associated with fluorescence imaging and permits the long-term, nonlethal observation of living cells. Thus, bioluminescence microscopy would be a powerful tool in cellular biology that complements fluorescence microscopy.

  17. Construction of a bioluminescence reporter plasmid for Francisella tularensis

    OpenAIRE

    Bina, Xiaowen R.; Miller, Mark A.; James E Bina

    2010-01-01

    A Francisella tularensis shuttle vector that constitutively expresses the Photorhabdus luminescens lux operon in type A and type B strains of F. tularensis was constructed. The bioluminescence reporter plasmid was introduced into the live vaccine strain of F. tularensis and used to follow F. tularensis growth in a murine intranasal challenge model in real time by bioluminescence imaging. The results show that the new bioluminescence reporter plasmid represents a useful tool for tularemia rese...

  18. In Vivo Bioluminescence Imaging of the Murine Pathogen Citrobacter rodentium

    OpenAIRE

    Wiles, Siouxsie; Pickard, Karen M.; Peng, Katian; MacDonald, Thomas T.; Frankel, Gad

    2006-01-01

    Citrobacter rodentium is a natural mouse pathogen related to enteropathogenic and enterohemorrhagic Escherichia coli. We have previously utilized bioluminescence imaging (BLI) to determine the in vivo colonization dynamics of C. rodentium. However, due to the oxygen requirement of the bioluminescence system and the colonic localization of C. rodentium, in vivo localization studies were performed using harvested organs. Here, we report the detection of bioluminescent C. rodentium and commensal...

  19. Reliability of a bioluminescence ATP assay for detection of bacteria.

    OpenAIRE

    Selan, L.; Berlutti, F; Passariello, C.; Thaller, M C; Renzini, G

    1992-01-01

    The reliability of bioluminescence assays which employ the luciferin-luciferase ATP-dependent reaction to evaluate bacterial counts was studied, both in vitro and on urine specimens. Bioluminescence and cultural results for the most common urinary tract pathogens were analyzed. Furthermore, the influence of the culture medium, of the assaying method, and of the phase of growth on bioluminescence readings was studied. Results show that Proteus, Providencia, and Morganella strains are not corre...

  20. Bioluminescent Probe for Detecting Mercury(II) in Living Mice.

    Science.gov (United States)

    Jiang, Tianyu; Ke, Bowen; Chen, Hui; Wang, Weishan; Du, Lupei; Yang, Keqian; Li, Minyong

    2016-08-01

    A novel bioluminescence probe for mercury(II) was obtained on the basis of the distinct deprotection reaction of dithioacetal to decanal, so as to display suitable sensitivity and selectivity toward mercury(II) over other ions with bacterial bioluminescence signal. These experimental results indicated such a probe was a novel promising method for mercury(II) bioluminescence imaging in environmental and life sciences ex vivo and in vivo. PMID:27412583

  1. Effect of electromagnetic fields on the bacteria bioluminescent activity

    International Nuclear Information System (INIS)

    The effect of electromagnetic field with frequency from 36.2 to 55.9 GHz on bioluminescence activity of bacterium were investigated. Electromagnetic field results in decrease of bioluminescence, which depends from frequency. The electromagnetic field adaptation time is higher of intrinsic time parameters of bioluminescence system. The effect has nonthermal nature. It is suggested that electromagnetic field influence connects with structure rearrangements near cell emitter. 8 refs.; 3 figs

  2. Bioluminescence in the high Arctic during the polar night

    OpenAIRE

    Berge, Jørgen; Båtnes, Anna Solvang; Johnsen, Geir; Blackwell, Susan; Moline, Mark A.

    2012-01-01

    This study examines the composition and activity of the planktonic community during the polar night in the high Arctic Kongsfjord, Svalbard. Our results are the first published evidence of bioluminescence among zooplankton during the Arctic polar night. The observations were collected by a bathyphotometer detecting bioluminescence, integrated into an autonomous underwater vehicle, to determine the concentration and intensity of bioluminescent flashes as a function of time of day and depth. To...

  3. Construction of a Bioluminescent Reporter Strain To Detect Polychlorinated Biphenyls

    OpenAIRE

    Layton, A C; Muccini, M.; Ghosh, M. M.; Sayler, G. S.

    1998-01-01

    A bioluminescent reporter strain, Ralstonia eutropha ENV307(pUTK60), was constructed for the detection of polychlorinated biphenyls by inserting the biphenyl promoter upstream of the bioluminescence genes. In the presence of a nonionic surfactant, which enhances the solubility of chlorinated biphenyls, bioluminescence was induced three- to fourfold over background by biphenyl, monochlorinated biphenyls, and Aroclor 1242. The minimum detection limits for these compounds ranged from 0.15 mg/lit...

  4. Stimulated bioluminescence by fluid shear stress associated with pipe flow

    Energy Technology Data Exchange (ETDEWEB)

    Cao Jing; Wang Jiangan; Wu Ronghua, E-mail: caojing981@126.com [Col. of Electronic Eng., Naval University of Engineering, Wuhan 430033 (China)

    2011-01-01

    Dinoflagellate can be stimulated bioluminescence by hydrodynamic agitation. Two typical dinoflagellate (Lingulodinium polyedrum and Pyrocystis noctiluca) was choosed to research stimulated bioluminescence. The bioluminescence intensity and shear stress intensity were measured using fully developed pipe flow. There is shear stress threshold to agitate organism bioluminescence. From these experiment, the response thresholds of the stimulated bioluminscence always occurred in laminar flows at a shear stress level of 0.6-3 dyn/cm{sup 2}. At the same time, the spectral characteristc of dinoflagellate was recorded, the wavelength of them is about 470nm, and the full width at half maximum is approximate 30nm.

  5. Transformation Experiment Using Bioluminescence Genes of "Vibrio fischeri."

    Science.gov (United States)

    Slock, James

    1995-01-01

    Bioluminescence transformation experiments show students the excitement and power of recombinant DNA technology. This laboratory experiment utilizes two plasmids of "Vibrio fischeri" in a transformation experiment. (LZ)

  6. Stimulated bioluminescence by fluid shear stress associated with pipe flow

    International Nuclear Information System (INIS)

    Dinoflagellate can be stimulated bioluminescence by hydrodynamic agitation. Two typical dinoflagellate (Lingulodinium polyedrum and Pyrocystis noctiluca) was choosed to research stimulated bioluminescence. The bioluminescence intensity and shear stress intensity were measured using fully developed pipe flow. There is shear stress threshold to agitate organism bioluminescence. From these experiment, the response thresholds of the stimulated bioluminscence always occurred in laminar flows at a shear stress level of 0.6-3 dyn/cm2. At the same time, the spectral characteristc of dinoflagellate was recorded, the wavelength of them is about 470nm, and the full width at half maximum is approximate 30nm.

  7. Understanding Bioluminescence in Dinoflagellates—How Far Have We Come?

    Science.gov (United States)

    Valiadi, Martha; Iglesias-Rodriguez, Debora

    2013-01-01

    Some dinoflagellates possess the remarkable genetic, biochemical, and cellular machinery to produce bioluminescence. Bioluminescent species appear to be ubiquitous in surface waters globally and include numerous cosmopolitan and harmful taxa. Nevertheless, bioluminescence remains an enigmatic topic in biology, particularly with regard to the organisms’ lifestyle. In this paper, we review the literature on the cellular mechanisms, molecular evolution, diversity, and ecology of bioluminescence in dinoflagellates, highlighting significant discoveries of the last quarter of a century. We identify significant gaps in our knowledge and conflicting information and propose some important research questions that need to be addressed to advance this research field.

  8. Blob-Based Discrete Imaging Models for Three-Dimensional Optoacoustic Tomography

    CERN Document Server

    Wang, Kun; Su, Richard; Oraevsky, Alexander; Anastasio, Mark A

    2013-01-01

    Optoacoustic tomography (OAT), also known as photoacoustic tomography, is an emerging computed biomedical imaging modality that exploits optical contrast and ultrasonic detection principles. Iterative image reconstruction algorithms that are based on discrete imaging models are actively being developed for OAT due to their ability to improve image quality by incorporating accurate models of the imaging physics, instrument response, and measurement noise.In this work, we investigate the use of discrete imaging models based on Kaiser-Bessel window functions, or `blobs', for iterative image reconstruction in OAT.A closed-form expression for the pressure produced by a blob function is calculated, which facilitates accurate computation of the system matrix. Computer-simulation and experimental studies are employed to demonstrate the potential advantages of blob-based iterative image reconstruction in OAT.

  9. Time resolution in scintillator based detectors for positron emission tomography

    International Nuclear Information System (INIS)

    In the domain of medical photon detectors L(Y)SO scintillators are used for positron emission tomography (PET). The interest for time of flight (TOF) in PET is increasing since measurements have shown that new crystals like L(Y)SO coupled to state of the art photodetectors, e.g. silicon photomultipliers (SiPM), can reach coincidence time resolutions (CTRs) of far below 500ps FWHM. To achieve these goals it is important to study the processe in the whole detection chain, i.e. the high energy particle or gamma interaction in the crystal, the scintillation process itself, the light propagation in the crystal with the light transfer to the photodetector, and the electronic readout. In this thesis time resolution measurements for a PET like system are performed in a coincidence setup utilizing the ultra fast amplifier discriminator NINO. We found that the time-over-threshold energy information provided by NINO shows a degradation in energy resolution for higher SiPM bias voltages. This is a consequence of the increasing dark count rate (DCR) of the SiPM with higher bias voltages together with the exponential decay of the signal. To overcome this problem and to operate the SiPM at its optimum voltage in terms of timing we developed a new electronic board that employs NINO only as a low noise leading edge discriminator together with an analog amplifier which delivers the energy information. With this new electronic board we indeed improved the measured CTR by about 15%. To study the limits of time resolution in more depth we measured the CTR with 2x2x3mm3 LSO:Ce codoped 0.4%Ca crystals coupled to commercially available SiPMs (Hamamatsu S10931-50P MPPC) and achieved a CTR of 108±5ps FWHM at an energy of 511keV. We determined the influence of the data acquisition system and the electronics on the CTR to be 27±2ps FWHM and thus negligible. To quantitatively understand the measured values, we developed a Monte Carlo simulation tool in MATLAB that incorporates the timing

  10. Bioluminescence ATP monitoring for the routine assessment of food contact surface cleanliness in a university canteen.

    Science.gov (United States)

    Osimani, Andrea; Garofalo, Cristiana; Clementi, Francesca; Tavoletti, Stefano; Aquilanti, Lucia

    2014-10-17

    ATP bioluminescence monitoring and traditional microbiological analyses (viable counting of total mesophilic aerobes, coliforms and Escherichia coli) were used to evaluate the effectiveness of Sanitation Standard Operating Procedures (SSOP) at a university canteen which uses a HACCP-based approach. To that end, 10 cleaning control points (CPs), including food contact surfaces at risk of contamination from product residues or microbial growth, were analysed during an 8-month monitoring period. Arbitrary acceptability limits were set for both microbial loads and ATP bioluminescence readings. A highly significant correlation (r = 0.99) between the means of ATP bioluminescence readings and the viable counts of total mesophilic aerobes was seen, thus revealing a strong association of these parameters with the level of surface contamination. Among CPs, the raw meat and multi-purpose chopping boards showed the highest criticalities. Although ATP bioluminescence technology cannot substitute traditional microbiological analyses for the determination of microbial load on food contact surfaces, it has proved to be a powerful tool for the real time monitoring of surface cleanliness at mass catering plants, for verify the correct application of SSOP, and hence for their implementation/revision in the case of poor hygiene.

  11. Bioluminescence ATP Monitoring for the Routine Assessment of Food Contact Surface Cleanliness in a University Canteen

    Directory of Open Access Journals (Sweden)

    Andrea Osimani

    2014-10-01

    Full Text Available ATP bioluminescence monitoring and traditional microbiological analyses (viable counting of total mesophilic aerobes, coliforms and Escherichia coli were used to evaluate the effectiveness of Sanitation Standard Operating Procedures (SSOP at a university canteen which uses a HACCP-based approach. To that end, 10 cleaning control points (CPs, including food contact surfaces at risk of contamination from product residues or microbial growth, were analysed during an 8-month monitoring period. Arbitrary acceptability limits were set for both microbial loads and ATP bioluminescence readings. A highly significant correlation (r = 0.99 between the means of ATP bioluminescence readings and the viable counts of total mesophilic aerobes was seen, thus revealing a strong association of these parameters with the level of surface contamination. Among CPs, the raw meat and multi-purpose chopping boards showed the highest criticalities. Although ATP bioluminescence technology cannot substitute traditional microbiological analyses for the determination of microbial load on food contact surfaces, it has proved to be a powerful tool for the real time monitoring of surface cleanliness at mass catering plants, for verify the correct application of SSOP, and hence for their implementation/revision in the case of poor hygiene.

  12. Positron emission tomography displacement sensitivity: predicting binding potential change for positron emission tomography tracers based on their kinetic characteristics.

    Science.gov (United States)

    Morris, Evan D; Yoder, Karmen K

    2007-03-01

    There is great interest in positron emission tomography (PET) as a noninvasive assay of fluctuations in synaptic neurotransmitter levels, but questions remain regarding the optimal choice of tracer for such a task. A mathematical method is proposed for predicting the utility of any PET tracer as a detector of changes in the concentration of an endogenous competitor via displacement of the tracer (a.k.a., its 'vulnerability' to competition). The method is based on earlier theoretical work by Endres and Carson and by the authors. A tracer-specific predictor, the PET Displacement Sensitivity (PDS), is calculated from compartmental model simulations of the uptake and retention of dopaminergic radiotracers in the presence of transient elevations of dopamine (DA). The PDS predicts the change in binding potential (DeltaBP) for a given change in receptor occupancy because of binding by the endogenous competitor. Simulations were performed using estimates of tracer kinetic parameters derived from the literature. For D(2)/D(3) tracers, the calculated PDS indices suggest a rank order for sensitivity to displacement by DA as follows: raclopride (highest sensitivity), followed by fallypride, FESP, FLB, NMSP, and epidepride (lowest). Although the PDS takes into account the affinity constant for the tracer at the binding site, its predictive value cannot be matched by either a single equilibrium constant, or by any one rate constant of the model. Values for DeltaBP have been derived from published studies that employed comparable displacement paradigms with amphetamine and a D(2)/D(3) tracer. The values are in good agreement with the PDS-predicted rank order of sensitivity to displacement. PMID:16788713

  13. 2.5D dictionary learning based computed tomography reconstruction

    Science.gov (United States)

    Luo, Jiajia; Eri, Haneda; Can, Ali; Ramani, Sathish; Fu, Lin; De Man, Bruno

    2016-05-01

    A computationally efficient 2.5D dictionary learning (DL) algorithm is proposed and implemented in the model- based iterative reconstruction (MBIR) framework for low-dose CT reconstruction. MBIR is based on the minimization of a cost function containing data-fitting and regularization terms to control the trade-off between data-fidelity and image noise. Due to the strong denoising performance of DL, it has previously been considered as a regularizer in MBIR, and both 2D and 3D DL implementations are possible. Compared to the 2D case, 3D DL keeps more spatial information and generates images with better quality although it requires more computation. We propose a novel 2.5D DL scheme, which leverages the computational advantage of 2D-DL, while attempting to maintain reconstruction quality similar to 3D-DL. We demonstrate the effectiveness of this new 2.5D DL scheme for MBIR in low-dose CT. By applying the 2D DL method in three different orthogonal planes and calculating the sparse coefficients accordingly, much of the 3D spatial information can be preserved without incurring the computational penalty of the 3D DL method. For performance evaluation, we use baggage phantoms with different number of projection views. In order to quantitatively compare the performance of different algorithms, we use PSNR, SSIM and region based standard deviation to measure the noise level, and use the edge response to calculate the resolution. Experimental results with full view datasets show that the different DL based algorithms have similar performance and 2.5D DL has the best resolution. Results with sparse view datasets show that 2.5D DL outperforms both 2D and 3D DL in terms of noise reduction. We also compare the computational costs, and 2.5D DL shows strong advantage over 3D DL in both full-view and sparse-view cases.

  14. Task-Based Optimization of Computed Tomography Imaging Systems

    CERN Document Server

    Sanchez, Adrian A

    2015-01-01

    The goal of this thesis is to provide a framework for the use of task-based metrics of image quality to aid in the design, implementation, and evaluation of CT image reconstruction algorithms and CT systems in general. We support the view that task-based metrics of image quality can be useful in guiding the algorithm design and implementation process in order to yield images of objectively superior quality and higher utility for a given task. Further, we believe that metrics such as the Hotelling observer (HO) SNR can be used as summary scalar metrics of image quality for the evaluation of images produced by novel reconstruction algorithms. In this work, we aim to construct a concise and versatile formalism for image reconstruction algorithm design, implementation, and assessment. The bulk of the work focuses on linear analytical algorithms, specifically the ubiquitous filtered back-projection (FBP) algorithm. However, due to the demonstrated importance of optimization-based algorithms in a wide variety of CT...

  15. Fiber-Based Polarization Diversity Detection for Polarization-Sensitive Optical Coherence Tomography

    OpenAIRE

    Hamid Pahlevaninezhad; Lee, Anthony M. D.; Lucas Cahill; Stephen Lam; Calum MacAulay; Pierre Lane

    2014-01-01

    We present a new fiber-based polarization diversity detection (PDD) scheme for polarization sensitive optical coherence tomography (PSOCT). This implementation uses a new custom miniaturized polarization-maintaining fiber coupler with single mode (SM) fiber inputs and polarization maintaining (PM) fiber outputs. The SM fiber inputs obviate matching the optical lengths of the two orthogonal OCT polarization channels prior to interference while the PM fiber outputs ensure defined orthogonal axe...

  16. Contextual Multivariate Segmentation of Pork Tissue from Grating-Based Multimodal X-Ray Tomography

    OpenAIRE

    Einarsdottir, Hildur; Nielsen, Mikkel S.; Ersbøll, Bjarne Kjær; Larsen, Rasmus; Bech, Martin; Pfeier, Franz; Christensen, Lars B.; Feidenhans'l, Robert

    2013-01-01

    X-ray computed tomography is increasingly used as a nondestructive method for studying three dimensional food structures. For meat products, studies have focused mainly on fat and protein content due to limited contrast capabilities of absorption based techniques. Recent advances in X-ray imaging have made novel X-ray image modalities available, where the refraction and scattering of X-rays is obtained simultaneously with the absorption properties, providing enhanced contrast for soft biologi...

  17. Computed tomography-based finite element analysis to assess fracture risk and osteoporosis treatment

    OpenAIRE

    Imai, Kazuhiro

    2015-01-01

    Finite element analysis (FEA) is a computer technique of structural stress analysis and developed in engineering mechanics. FEA has developed to investigate structural behavior of human bones over the past 40 years. When the faster computers have acquired, better FEA, using 3-dimensional computed tomography (CT) has been developed. This CT-based finite element analysis (CT/FEA) has provided clinicians with useful data. In this review, the mechanism of CT/FEA, validation studies of CT/FEA to e...

  18. Polarization sensitive optical coherence tomography of melanin provides intrinsic contrast based on depolarization

    OpenAIRE

    Baumann, Bernhard; Baumann, Stefan O.; Konegger, Thomas; Pircher, Michael; Götzinger, Erich; Schlanitz, Ferdinand; Schütze, Christopher; Sattmann, Harald; Litschauer, Marco; Schmidt-Erfurth, Ursula; Hitzenberger, Christoph K.

    2012-01-01

    Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of OCT. In addition to imaging based on tissue reflectivity, PS-OCT also enables depth-resolved mapping of sample polarization properties such as phase-retardation, birefringent axis orientation, Stokes vectors, and degree of polarization uniformity (DOPU). In this study, PS-OCT was used to investigate the polarization properties of melanin. In-vitro measurements in samples with varying melanin concentratio...

  19. Optical coherence tomography based microangiography: A tool good for dermatology applications (Conference Presentation)

    Science.gov (United States)

    Wang, Ruikang K.; Baran, Utku; Choi, Woo J.

    2016-02-01

    Optical coherence tomography (OCT) based microangiography (OMAG) is a new imaging technique enabling the visualization of blood flow within microcirculatory tissue beds in vivo with high resolution. In this talk, the concept and advantages of OMAG will be discussed and its potential clinical applications in the dermatology will be shown, demonstrating its usefulness in the clinical monitoring and therapeutic treatment of various skin pathologies, e.g. acne, port wine stain and wound healing.

  20. Atom-probe tomography of tribological boundary films resulting from boron-based oil additives

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoon-Jun; Baik, Sung-Il; Bertolucci-Coelho, Leonardo; Mazzaferro, Lucca; Ramirez, Giovanni; Erdemir, Ali; Seidman, D K

    2016-01-15

    Correlative characterization using atom-probe tomography (APT) and transmission electron microscopy (TEM) was performed on a tribofilm formed during sliding frictional testing with a fully formulated engine oil, which also contains a boron-based additive. The tribofilm formed is ~15 nm thick and consists of oxides of iron and compounds of B, Ca, P, and S, which are present in the additive. This study provides strong evidence for boron being embedded in the tribofilm, which effectively reduces friction and wear losses.

  1. Swept Source Optical Coherence Tomography based Smart Handheld Vitreoretinal Microsurgical Tool for Tremor Suppression

    OpenAIRE

    Song, Cheol; Gehlbach, Peter L.; Kang, Jin U.

    2012-01-01

    Microsurgeons require the ability to make precise and stable maneuvers in order to achieve surgical objectives and to minimize surgical risks during freehand microsurgical procedures. This work presents a novel common path swept source optical coherence tomography based smart surgical tool that suppresses hand tremor. It allows enhanced tool tip stabilization, more accurate targeting and may lower surgical risk. Here the one dimensional motion tremor of a surgeon’s hand is assessed by the sur...

  2. Iterative reconstruction methods in atmospheric tomography: FEWHA, Kaczmarz and Gradient-based algorithm

    Science.gov (United States)

    Ramlau, R.; Saxenhuber, D.; Yudytskiy, M.

    2014-07-01

    The problem of atmospheric tomography arises in ground-based telescope imaging with adaptive optics (AO), where one aims to compensate in real-time for the rapidly changing optical distortions in the atmosphere. Many of these systems depend on a sufficient reconstruction of the turbulence profiles in order to obtain a good correction. Due to steadily growing telescope sizes, there is a strong increase in the computational load for atmospheric reconstruction with current methods, first and foremost the MVM. In this paper we present and compare three novel iterative reconstruction methods. The first iterative approach is the Finite Element- Wavelet Hybrid Algorithm (FEWHA), which combines wavelet-based techniques and conjugate gradient schemes to efficiently and accurately tackle the problem of atmospheric reconstruction. The method is extremely fast, highly flexible and yields superior quality. Another novel iterative reconstruction algorithm is the three step approach which decouples the problem in the reconstruction of the incoming wavefronts, the reconstruction of the turbulent layers (atmospheric tomography) and the computation of the best mirror correction (fitting step). For the atmospheric tomography problem within the three step approach, the Kaczmarz algorithm and the Gradient-based method have been developed. We present a detailed comparison of our reconstructors both in terms of quality and speed performance in the context of a Multi-Object Adaptive Optics (MOAO) system for the E-ELT setting on OCTOPUS, the ESO end-to-end simulation tool.

  3. Bioluminescence enhancement through an added washing protocol enabling a greater sensitivity to carbofuran toxicity.

    Science.gov (United States)

    Jia, Kun; Eltzov, Evgeni; Marks, Robert S; Ionescu, Rodica E

    2013-10-01

    The effects of carbofuran toxicity on a genetically modified bacterial strain E. coli DPD2794 were enhanced using a new bioluminescent protocol which consisted of three consecutive steps: incubation, washing and luminescence reading. Specifically, in the first step, several concentrations of carbofuran aqueous solutions were incubated with different bacterial suspensions at recorded optical densities for different lengths of time. Thereafter, the resulting bacterial/toxicant mixtures were centrifuged and the aged cellular supernatant replaced with fresh medium. In the final step, the carbofuran- induced bioluminescence to the exposed E. coli DPD2794 bacteria was shown to provide a faster and higher intensity when recorded at a higher temperature at30°C which is not usually used in the literature. It was found that the incubation time and the replacement of aged cellular medium were essential factors to distinguish different concentrations of carbofuran in the bioluminescent assays. From our results, the optimum incubation time for a "light ON" bioluminescence detection of the effect of carbofuran was 6h. Thanks to the replacement of the aged cellular medium, a group of additional peaks starting around 30min were observed and we used the corresponding areas under the curve (AUC) at different contents of carbofuran to produce the calibration curve. Based on the new protocol, a carbofuran concentration of 0.5pg/mL can be easily determined in a microtiter plate bioluminescent assay, while a non-wash protocol provides an unexplainable order of curve evolutionswhich does not allow the user to determine the concentration. PMID:23867093

  4. Bioluminescence enhancement through an added washing protocol enabling a greater sensitivity to carbofuran toxicity.

    Science.gov (United States)

    Jia, Kun; Eltzov, Evgeni; Marks, Robert S; Ionescu, Rodica E

    2013-10-01

    The effects of carbofuran toxicity on a genetically modified bacterial strain E. coli DPD2794 were enhanced using a new bioluminescent protocol which consisted of three consecutive steps: incubation, washing and luminescence reading. Specifically, in the first step, several concentrations of carbofuran aqueous solutions were incubated with different bacterial suspensions at recorded optical densities for different lengths of time. Thereafter, the resulting bacterial/toxicant mixtures were centrifuged and the aged cellular supernatant replaced with fresh medium. In the final step, the carbofuran- induced bioluminescence to the exposed E. coli DPD2794 bacteria was shown to provide a faster and higher intensity when recorded at a higher temperature at30°C which is not usually used in the literature. It was found that the incubation time and the replacement of aged cellular medium were essential factors to distinguish different concentrations of carbofuran in the bioluminescent assays. From our results, the optimum incubation time for a "light ON" bioluminescence detection of the effect of carbofuran was 6h. Thanks to the replacement of the aged cellular medium, a group of additional peaks starting around 30min were observed and we used the corresponding areas under the curve (AUC) at different contents of carbofuran to produce the calibration curve. Based on the new protocol, a carbofuran concentration of 0.5pg/mL can be easily determined in a microtiter plate bioluminescent assay, while a non-wash protocol provides an unexplainable order of curve evolutionswhich does not allow the user to determine the concentration.

  5. A REVIEW OF ENVIRONMENTAL APPLICATIONS OF BIOLUMINESCENCE MEASUREMENTS

    Science.gov (United States)

    This review of the recent literature on environmental applications of bioluminescence systems will focus on in vivo and in vitro bioluminescence methods that have been utilized to elucidate properties of chemicals, toxic and mutagenic effects, and to estimate biomass. The unifyin...

  6. Detection of ATP and NADH: A Bioluminescent Experience.

    Science.gov (United States)

    Selig, Ted C.; And Others

    1984-01-01

    Described is a bioluminescent assay for adenosine triphosphate (ATP) and reduced nicotineamide-adenine dinucleotide (NADH) that meets the requirements of an undergraduate biochemistry laboratory course. The 3-hour experiment provides students with experience in bioluminescence and analytical biochemistry yet requires limited instrumentation,…

  7. Use of the liquid scintillation spectrometer in bioluminescence analysis

    International Nuclear Information System (INIS)

    This review covers publications concerning analytical bioluminescence which in the main have appeared between mid-1973 and mid-1976. Outlines of some new assays and techniques are given together with modifications of existing procedures. Comments are presented on the use of the liquid scintillation spectrometer and other equipment for measuring bioluminescence. New applications are detailed and discussed

  8. In Vivo Bioluminescent Imaging of ATP-Binding Cassette Transporter-Mediated Efflux at the Blood-Brain Barrier.

    Science.gov (United States)

    Bakhsheshian, Joshua; Wei, Bih-Rong; Hall, Matthew D; Simpson, R Mark; Gottesman, Michael M

    2016-01-01

    We provide a detailed protocol for imaging ATP-binding cassette subfamily G member 2 (ABCG2) function at the blood-brain barrier (BBB) of transgenic mice. D-Luciferin is specifically transported by ABCG2 found on the apical side of endothelial cells at the BBB. The luciferase-luciferin enzymatic reaction produces bioluminescence, which allows a direct measurement of ABCG2 function at the BBB. Therefore bioluminescence imaging (BLI) correlates with ABCG2 function at the BBB and this can be measured by administering luciferin in a mouse model that expresses luciferase in the brain parenchyma. BLI allows for a relatively low-cost alternative for studying transporter function in vivo compared to other strategies such as positron emission tomography. This method for imaging ABCG2 function at the BBB can be used to investigate pharmacokinetic inhibition of the transporter. PMID:27424909

  9. Measuring ligand-dependent and ligand-independent interactions between nuclear receptors and associated proteins using Bioluminescence Resonance Energy Transfer (BRET2)

    OpenAIRE

    Koterba, Kristen L.; Rowan, Brian G.

    2006-01-01

    Bioluminescent resonance energy transfer (BRET2) is a recently developed technology for the measurement of protein-protein interactions in a live, cell-based system. BRET2 is characterized by the efficient transfer of excited energy between a bioluminescent donor molecule (Renilla luciferase) and a fluorescent acceptor molecule (a mutant of Green Fluorescent Protein (GFP2)). The BRET2 assay offers advantages over fluorescence resonance energy transfer (FRET) because it does not require an ext...

  10. Propagation-based phase-contrast tomography for high-resolution lung imaging with laboratory sources

    Science.gov (United States)

    Krenkel, Martin; Töpperwien, Mareike; Dullin, Christian; Alves, Frauke; Salditt, Tim

    2016-03-01

    We have performed high-resolution phase-contrast tomography on whole mice with a laboratory setup. Enabled by a high-brilliance liquid-metal-jet source, we show the feasibility of propagation-based phase contrast in local tomography even in the presence of strongly absorbing surrounding tissue as it is the case in small animal imaging of the lung. We demonstrate the technique by reconstructions of the mouse lung for two different fields of view, covering the whole organ, and a zoom to the local finer structure of terminal airways and alveoli. With a resolution of a few micrometers and the wide availability of the technique, studies of larger biological samples at the cellular level become possible.

  11. A new recontruction algorithm for use with capacitance-based tomography

    Directory of Open Access Journals (Sweden)

    Ø. Isaksen

    1994-01-01

    Full Text Available A new reconstruction algorithm for use with capacitance-based process tomography is proposed. A numerical simulator, capable of calculating the capacitances for a particular sensor configuration and flow regime is used together with a parameter representation of the dielectric distribution and an optimization algorithm. The algorithm calculates these parameters and hence the dielectric distribution, by minimizing a function defined as a weighted sum of square differences between the measured and estimated capacitances. The method is tested by using both synthetic and experimental data, and the results are compared with results from the commonly used Linear Back Projection (LBP algorithm. The method is capable of obtaining the correct parameter values for all the flow regimes tested, and does provide a better estimate than the LBP method. The method proves to be very promising, and is a step towards quantitative capacitance tomography.

  12. Propagation-based phase-contrast tomography for high-resolution lung imaging with laboratory sources

    Directory of Open Access Journals (Sweden)

    Martin Krenkel

    2016-03-01

    Full Text Available We have performed high-resolution phase-contrast tomography on whole mice with a laboratory setup. Enabled by a high-brilliance liquid-metal-jet source, we show the feasibility of propagation-based phase contrast in local tomography even in the presence of strongly absorbing surrounding tissue as it is the case in small animal imaging of the lung. We demonstrate the technique by reconstructions of the mouse lung for two different fields of view, covering the whole organ, and a zoom to the local finer structure of terminal airways and alveoli. With a resolution of a few micrometers and the wide availability of the technique, studies of larger biological samples at the cellular level become possible.

  13. Dinoflagellate bioluminescence in response to mechanical stimuli in water flows

    Directory of Open Access Journals (Sweden)

    A. S. Cussatlegras

    2005-01-01

    Full Text Available Bioluminescence of plankton organisms induced by water movements has long been observed and is still under investigations because of its great complexity. In particular, the exact mechanism occurring at the level of the cell has not been yet fully understood. This work is devoted to the study of the bioluminescence of the dinoflagellates plankton species Pyrocystis noctiluca in response to mechanical stimuli generated by water flows. Several experiments were performed with different types of flows in a Couette shearing apparatus. All of them converge to the conclusion that stationary homogeneous laminar shear does not trigger massive bioluminescence, but that acceleration and shear are both necessary to stimulate together an intense bioluminescence response. The distribution of the experimental bioluminescence thresholds is finally calculated from the light emission response for the Pyrocystis noctiluca species.

  14. The bottom oxygen border of bioluminescence distribution in ocean

    Science.gov (United States)

    Zavoruev, Valerii

    2006-02-01

    From materials of forwarding researches follows, that the depth of deposition of the bottom border of bioluminescence plankton has not correlation with any of measurable hydrological parameters. As the reaction of bioluminescence is oxygen depended, it was logical to assume, that the situation of the bottom maximum of luminescence plankton is determined by concentration of oxygen. The data of vertical distribution of bioluminescence intensity of plankton and concentration of oxygen received in the Black Sea and near to east coast of America were investigated. Is established, that the deep maximum of bioluminescence of plankton is found out between isooxygen 0.35 and 0.20 ml/l. At concentration of oxygen in water is lower 0.10-0.20 ml/l the bioluminescence of plankton it is not found out.

  15. Bioluminescence in the high Arctic during the polar night.

    Science.gov (United States)

    Berge, J; Båtnes, A S; Johnsen, G; Blackwell, S M; Moline, M A

    2012-01-01

    This study examines the composition and activity of the planktonic community during the polar night in the high Arctic Kongsfjord, Svalbard. Our results are the first published evidence of bioluminescence among zooplankton during the Arctic polar night. The observations were collected by a bathyphotometer detecting bioluminescence, integrated into an autonomous underwater vehicle, to determine the concentration and intensity of bioluminescent flashes as a function of time of day and depth. To further understand community dynamics and composition, plankton nets were used to collect organisms passing through the bathyphotometer along with traditional vertical net tows. Additionally, using a moored bathyphotometer closed to the sampling site, the bioluminescence potential itself was shown not to have a diurnal or circadian rhythm. Rather, our results provide evidence for a diel vertical migration of bioluminescent zooplankton that does not correspond to any externally detectable changes in illumination.

  16. Dinoflagellate bioluminescence in response to mechanical stimuli in water flows

    Science.gov (United States)

    Cussatlegras, A. S.; Le Gal, P.

    2005-02-01

    Bioluminescence of plankton organisms induced by water movements has long been observed and is still under investigations because of its great complexity. In particular, the exact mechanism occurring at the level of the cell has not been yet fully understood. This work is devoted to the study of the bioluminescence of the dinoflagellates plankton species Pyrocystis noctiluca in response to mechanical stimuli generated by water flows. Several experiments were performed with different types of flows in a Couette shearing apparatus. All of them converge to the conclusion that stationary homogeneous laminar shear does not trigger massive bioluminescence, but that acceleration and shear are both necessary to stimulate together an intense bioluminescence response. The distribution of the experimental bioluminescence thresholds is finally calculated from the light emission response for the Pyrocystis noctiluca species.

  17. Are we ready for positron emission tomography/computed tomography-based target volume definition in lymphoma radiation therapy?

    Science.gov (United States)

    Yeoh, Kheng-Wei; Mikhaeel, N George

    2013-01-01

    Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has become indispensable for the clinical management of lymphomas. With consistent evidence that it is more accurate than anatomic imaging in the staging and response assessment of many lymphoma subtypes, its utility continues to increase. There have therefore been efforts to incorporate PET/CT data into radiation therapy decision making and in the planning process. Further, there have also been studies investigating target volume definition for radiation therapy using PET/CT data. This article will critically review the literature and ongoing studies on the above topics, examining the value and methods of adding PET/CT data to the radiation therapy treatment algorithm. We will also discuss the various challenges and the areas where more evidence is required.

  18. Whole-cell bioluminescent bioreporter sensing of foodborne toxicants

    Science.gov (United States)

    Ripp, Steve A.; Applegate, Bruce M.; Simpson, Michael L.; Sayler, Gary S.

    2001-03-01

    The presence of biologically derived toxins in foods is of utmost significance to food safety and human health concerns. Biologically active amines, referred to as biogenic amines, serve as a noteworthy example, having been implicated as the causative agent in numerous food poisoning episodes. Of the various biogenic amines encountered, histamine, putrescine, cadaverine, tyramine, tryptamine, beta-phenylethylamine, spermine, and spermidine are considered to be the most significant, and can be used as hygienic-quality indicators of food. Biogenic amines can be monitored using whole-cell bioluminescent bioreporters, which represent a family of genetically engineered microorganisms that generate visible light in response to specific chemical or physical agents in their environment. The light response occurs due to transcriptional activation of a genetically incorporated lux cassette, and can be measured using standard photomultiplier devices. We have successfully engineered a lux-based bioreporter capable of detecting and monitoring the biogenic amine beta-phenylethylamine. This research represents a biologically-based sensor technology that can be readily integrated into Hazard Analysis Critical Control Point programs to provide a rugged monitoring regime that can be uniformly applied for field-based and in-house laboratory quality control analyses. Since the bioreporter and biosensing elements are completely self-contained within the sensor design, this system provides ease of use, with operational capabilities realized by simply combining the food sample with the bioreporter and allowing the sensor to process the ensuing bioluminescent signal and communicate the results. The application of this technology to the critically important issue of food safety and hygienic quality represents a novel method for detecting, monitoring, and preventing biologically active toxins in food commodities.

  19. Application value of ATP based bioluminescence tumor chemosensitivity assay in the chemotherapy for hydrothorax caused by non-small cell lung cancer

    Institute of Scientific and Technical Information of China (English)

    Kaijian Le; Yuming Jia; Jing Wang; Maoqiong Jiang

    2013-01-01

    Objective: The aim of the study was to investigate the clinical value and application of ATP based bioluminescencetumor chemosensitivity assay (ATP-TCA) in the chemotherapy for hydrothorax caused by non-small cell lung cancer(NSCLC). Methods: Hydrothorax specimens from 120 NSCLC patients were analyzed by ATP-TCA and the most sensitivechemotherapeutic drugs were used in NSCLC patients (treatment group). At the same time, 56 NSCLC patients with hydrothoraxwere admitted in our Hospital (Department of Oncology, The No. 2 People's Hospital of Yibin, China) and given chemotherapywithout guidance of the ATP-TCA (control group). Before the third chemotherapeutic cycle, clinical outcomes wereanalyzed in the two groups. Results: Effective rate of hydrothorax in treatment group was 67%, while 46% in control group(P < 0.05). In refractory hydrothorax patients, they were 69% and 40% (P < 0.05), respectively. In vitro results correlated wellwith clinical outcomes (P < 0.01). Conclusion: Effective rate of chemotherapy for hydrothorax in NSCLC is higher in treatmentgroup than that in control group. ATP-TCA is especially helpful for refractory hydrothorax.

  20. Autonomously Bioluminescent Mammalian Cells For Continuous And Real-Time Monitoring Of Cytotoxicity

    OpenAIRE

    Xu, Tingting; Close, Dan M.; Webb, James D; Ripp, Steven A.; Sayler, Gary S.

    2013-01-01

    Mammalian cell-based in vitro assays have been widely employed as alternatives to animal testing for toxicological studies but have been limited due to the high monetary and time costs of parallel sample preparation that are necessitated due to the destructive nature of firefly luciferase-based screening methods. This video describes the utilization of autonomously bioluminescent mammalian cells, which do not require the destructive addition of a luciferin substrate, as an inexpensive and fac...

  1. Comparison of Static and Microfluidic Protease Assays Using Modified Bioluminescence Resonance Energy Transfer Chemistry

    OpenAIRE

    Wu, Nan; Dacres, Helen; Anderson, Alisha; Stephen C Trowell; Zhu, Yonggang

    2014-01-01

    Background Fluorescence and bioluminescence resonance energy transfer (F/BRET) are two forms of Förster resonance energy transfer, which can be used for optical transduction of biosensors. BRET has several advantages over fluorescence-based technologies because it does not require an external light source. There would be benefits in combining BRET transduction with microfluidics but the low luminance of BRET has made this challenging until now. Methodology We used a thrombin bioprobe based on...

  2. [Study on Non-Destructive Testing of Guqin Interior Structure Based on Computed Tomography].

    Science.gov (United States)

    Zhao, De-da; Liu, Xing-e; Yang, Shu-min; Yu, Shenz; Tian, Gen-lin; Ma, Jian-feng; Wang, Qing-ping

    2015-12-01

    The wood property and production process affect quality of Guqin. At the same time, Guqin shape with cavity layout relations to the improvement of Guqin technology and inheritance, so it's very important to get the internal cavity characteristics and parameters on the condition of non-destructive the structure of Guqin. The image of interior structure in Guqin was investigated by overall scanning based on non-destructive testing technology of computed tomography, which texture of faceplate, connection method between faceplate and soleplate and interior defects were studied. The three-dimensional reconstruction of Guqin cavity was achieved through Mimics software of surface rendering method and put the two-dimensional CT tomography images convert into three-dimensional, which more complete show interior structural form in Guqin, and finally the parameter of cavity dimensions was obtained. Experimental research shows that there is significant difference in Guqin interior structure between Zhong-ni and Luo-xia type, in which the fluctuation of the interior surfacein Zhong-ni type's is larger than that in Luo-xia type; the interior volume of Zhong-ni typeis less than that of Luo-xia type, especially in Guqin neck. The accurate internal information of Guqin obtained through the computed tomography (CT) technology will provide technical support for the Guqin manufacture craft and the quality examination, as well as provide the reference in the aspect of non-destructive testing for other traditional precious internal structure research. PMID:26964242

  3. Bioluminescence imaging of wave-induced turbulence

    Science.gov (United States)

    Stokes, M. Dale; Deane, Grant B.; Latz, Michael I.; Rohr, Jim

    2004-01-01

    The ability to measure turbulent processes on small spatial and temporal scales is a long standing problem in physical oceanography. Here we explore a novel means of measuring fluid shear stress using the cell flashing behavior of bioluminescent dinoflagellates. To illustrate this technique, we present estimates of the heterogeneous, time-varying shear stress inside a breaking wave crest. These results have implications for a better understanding of upper ocean wave physics, air-sea gas transfer, and the biology of planktonic near-surface organisms as well as providing a new quantitative fluid visualization tool.

  4. Iterative Reconstruction of Computed Axial Tomography images based on GPUs; Reconstruccion Iterativa de Imagenes TAC basada en GPUs

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, V.; Florez, L. A.; Mayo, P.; Rodenas, F.; Verdu, G.

    2013-07-01

    Although widely used in nuclear medicine (gamma-cameras, SPECT-single photon emission computed tomography, positron emission tomography, PET), the iterative image reconstruction is not widespread in Computed tomography (CT). The biggest reason for this is that the data set required in TAC is much higher than in nuclear medicine and iterative reconstruction is computationally very intensive. The graphics processing units (GPUs) provide the possibility to reduce the high computational cost of rebuilding in an effective way. The objective of this work is to develop image reconstruction algorithm based on GPUs.

  5. Experimental approaches towards interpreting dolphin-stimulated bioluminescence.

    Science.gov (United States)

    Rohr, J; Latz, M I; Fallon, S; Nauen, J C; Hendricks, E

    1998-05-01

    Flow-induced bioluminescence provides a unique opportunity for visualizing the flow field around a swimming dolphin. Unfortunately, previous descriptions of dolphin-stimulated bioluminescence have been largely anecdotal and often conflicting. Most references in the scientific literature report an absence of bioluminescence on the dolphin body, which has been invariably assumed to be indicative of laminar flow. However, hydrodynamicists have yet to find compelling evidence that the flow remains laminar over most of the body. The present study integrates laboratory, computational and field approaches to begin to assess the utility of using bioluminescence as a method for flow visualization by relating fundamental characteristics of the flow to the stimulation of naturally occurring luminescent plankton. Laboratory experiments using fully developed pipe flow revealed that the bioluminescent organisms identified in the field studies can be stimulated in both laminar and turbulent flow when shear stress values exceed approximately 0.1 N m-2. Computational studies of an idealized hydrodynamic representation of a dolphin (modeled as a 6:1 ellipsoid), gliding at a speed of 2 m s-1, predicted suprathreshold surface shear stress values everywhere on the model, regardless of whether the boundary layer flow was laminar or turbulent. Laboratory flow visualization of a sphere demonstrated that the intensity of bioluminescence decreased with increasing flow speed due to the thinning of the boundary layer, while flow separation caused a dramatic increase in intensity due to the significantly greater volume of stimulating flow in the wake. Intensified video recordings of dolphins gliding at speeds of approximately 2 m s-1 confirmed that brilliant displays of bioluminescence occurred on the body of the dolphin. The distribution and intensity of bioluminescence suggest that the flow remained attached over most of the body. A conspicuous lack of bioluminescence was often observed on

  6. Comparison of in vitro breast cancer visibility in analyser-based computed tomography with histopathology, mammography, computed tomography and magnetic resonance imaging.

    Science.gov (United States)

    Keyriläinen, Jani; Fernández, Manuel; Bravin, Alberto; Karjalainen-Lindsberg, Marja Liisa; Leidenius, Marjut; von Smitten, Karl; Tenhunen, Mikko; Kangasmäki, Aki; Sipilä, Petri; Nemoz, Christian; Virkkunen, Pekka; Suortti, Pekka

    2011-09-01

    High-resolution analyser-based X-ray imaging computed tomography (HR ABI-CT) findings on in vitro human breast cancer are compared with histopathology, mammography, computed tomography (CT) and magnetic resonance imaging. The HR ABI-CT images provided significantly better low-contrast visibility compared with the standard radiological images. Fine cancer structures indistinguishable and superimposed in mammograms were seen, and could be matched with the histopathological results. The mean glandular dose was less than 1 mGy in mammography and 12-13 mGy in CT and ABI-CT. The excellent visibility of in vitro breast cancer suggests that HR ABI-CT may have a valuable role in the future as an adjunct or even alternative to current breast diagnostics, when radiation dose is further decreased, and compact synchrotron radiation sources become available. PMID:21862846

  7. Development of bioluminescent Salmonella strains for use in food safety

    Directory of Open Access Journals (Sweden)

    Bailey R Hartford

    2008-01-01

    Full Text Available Abstract Background Salmonella can reside in healthy animals without the manifestation of any adverse effects on the carrier. If raw products of animal origin are not handled properly during processing or cooked to a proper temperature during preparation, salmonellosis can occur. In this research, we developed bioluminescent Salmonella strains that can be used for real-time monitoring of the pathogen's growth on food products. To accomplish this, twelve Salmonella strains from the broiler production continuum were transformed with the broad host range plasmid pAKlux1, and a chicken skin attachment model was developed. Results Salmonella strains carrying pAKlux1 constitutively expressed the luxCDABE operon and were therefore detectable using bioluminescence. Strains were characterized in terms of bioluminescence properties and plasmid stability. To assess the usefulness of bioluminescent Salmonella strains in food safety studies, we developed an attachment model using chicken skin. The effect of washing on attachment of Salmonella strains to chicken skin was tested using bioluminescent strains, which revealed the attachment properties of each strain. Conclusion This study demonstrated that bioluminescence is a sensitive and effective tool to detect Salmonella on food products in real-time. Bioluminescence imaging is a promising technology that can be utilized to evaluate new food safety measures for reducing Salmonella contamination on food products.

  8. Detection of dichloromethane with a bioluminescent (lux) bacterial bioreporter.

    Science.gov (United States)

    Lopes, Nicholas; Hawkins, Shawn A; Jegier, Patricia; Menn, Fu-Min; Sayler, Gary S; Ripp, Steven

    2012-01-01

    The focus of this research effort was to develop an autonomous, inducible, lux-based bioluminescent bioreporter for the real-time detection of dichloromethane. Dichloromethane (DCM), also known as methylene chloride, is a volatile organic compound and one of the most commonly used halogenated solvents in the U.S., with applications ranging from grease and paint stripping to aerosol propellants and pharmaceutical tablet coatings. Predictably, it is released into the environment where it contaminates air and water resources. Due to its classification as a probable human carcinogen, hepatic toxin, and central nervous system effector, DCM must be carefully monitored and controlled. Methods for DCM detection usually rely on analytical techniques such as solid-phase microextraction (SPME) and capillary gas chromatography or photoacoustic environmental monitors, all of which require trained personnel and/or expensive equipment. To complement conventional monitoring practices, we have created a bioreporter for the self-directed detection of DCM by taking advantage of the evolutionary adaptation of bacteria to recognize and metabolize chemical agents. This bioreporter, Methylobacterium extorquens DCM( lux ), was engineered to contain a bioluminescent luxCDABE gene cassette derived from Photorhabdus luminescens fused downstream to the dcm dehalogenase operon, which causes the organism to generate visible light when exposed to DCM. We have demonstrated detection limits down to 1.0 ppm under vapor phase exposures and 0.1 ppm under liquid phase exposures with response times of 2.3 and 1.3 h, respectively, and with specificity towards DCM under relevant industrial environmental monitoring conditions.

  9. Photon Counting System for High-Sensitivity Detection of Bioluminescence at Optical Fiber End.

    Science.gov (United States)

    Iinuma, Masataka; Kadoya, Yutaka; Kuroda, Akio

    2016-01-01

    The technique of photon counting is widely used for various fields and also applicable to a high-sensitivity detection of luminescence. Thanks to recent development of single photon detectors with avalanche photodiodes (APDs), the photon counting system with an optical fiber has become powerful for a detection of bioluminescence at an optical fiber end, because it allows us to fully use the merits of compactness, simple operation, highly quantum efficiency of the APD detectors. This optical fiber-based system also has a possibility of improving the sensitivity to a local detection of Adenosine triphosphate (ATP) by high-sensitivity detection of the bioluminescence. In this chapter, we are introducing a basic concept of the optical fiber-based system and explaining how to construct and use this system.

  10. Photon Counting System for High-Sensitivity Detection of Bioluminescence at Optical Fiber End.

    Science.gov (United States)

    Iinuma, Masataka; Kadoya, Yutaka; Kuroda, Akio

    2016-01-01

    The technique of photon counting is widely used for various fields and also applicable to a high-sensitivity detection of luminescence. Thanks to recent development of single photon detectors with avalanche photodiodes (APDs), the photon counting system with an optical fiber has become powerful for a detection of bioluminescence at an optical fiber end, because it allows us to fully use the merits of compactness, simple operation, highly quantum efficiency of the APD detectors. This optical fiber-based system also has a possibility of improving the sensitivity to a local detection of Adenosine triphosphate (ATP) by high-sensitivity detection of the bioluminescence. In this chapter, we are introducing a basic concept of the optical fiber-based system and explaining how to construct and use this system. PMID:27424915

  11. Decision logic for retreatment of asymptomatic lung cancer recurrence based on positron emission tomography findings

    International Nuclear Information System (INIS)

    Purpose: The purpose of the study was to determine if Positron emission tomography (PET) 2-[F-18] fluoro-2-deoxy-D-glucose (FDG) imaging could detect subclinical local lung cancer recurrence and whether retreatment of such recurrence was feasible and beneficial. Methods and Materials: Twenty patients with biopsy proven lung cancer were studied with Positron emission tomography for the purpose of detecting subclinical lung cancer recurrence over a period of 4.25 years. All patients were treated with external radiation as part or all of their therapy. Twenty patients had baseline PET and computed tomography (CT) studies for comparison with later studies. Surviving patients had a total of 40 sequential PET scans and 35 CT scans. The follow-up interval ranged from 5 to 40 months posttreatment. The differential uptake ratio (DUR) was determined for regions of interest of increased FDG uptake. Results: The median DUR value of the 20 baseline PET studies was 5.59. The DUR value of greater than 3 was empirically selected as being positive for tumor detection. On baseline studies, PET had a 100% correlation with the CT findings in regard to detection of the site of primary tumor involvement. Four of 20 patients showed areas of discordance in the mediastinal and hilar areas on initial PET and CT studies. Seven of 17 patients showed discordant posttreatment PET-CT findings. Two false positive PET studies were due to radiation pneumonitis and one to macrophage glycolysis in tumor necrosis. For detection of asymptomatic tumor recurrence, analysis of sequential PET and CT studies, biopsy results, and the patient's clinical course suggested that PET had a sensitivity of 100%, specificity of 89.3%, and accuracy of 92.5%. Computerized Tomography was found to have a sensitivity of 67%, specificity of 85%, and accuracy of 82% for detection of such early-stage recurrence. Five patients went on to have retreatment with external irradiation based upon the PET evidence. Four retreated

  12. Role of certain amino acid residues of the coelenterazine-binding cavity in bioluminescence of light-sensitive Ca(2+)-regulated photoprotein berovin.

    Science.gov (United States)

    Burakova, Ludmila P; Stepanyuk, Galina A; Eremeeva, Elena V; Vysotski, Eugene S

    2016-05-11

    Bright bioluminescence of ctenophores is caused by Ca(2+)-regulated photoproteins. Although these photoproteins are functionally identical to and share many properties of cnidarian photoproteins, like aequorin and obelin, and retain the same spatial architecture, they are extremely sensitive to light, i.e. lose the ability to bioluminesce on exposure to light over the entire absorption spectrum. In addition, the degree of identity of their amino acid sequences with those of cnidarian photoproteins is only 29.4%. This suggests that the residues involved in bioluminescence of ctenophore and cnidarian photoproteins significantly differ. Here we describe the bioluminescent properties of berovin mutants with substitution of the residues located in the photoprotein internal cavity. Since the spatial structure of berovin bound with a substrate is not determined yet, to identify these residues we have modeled it with an accommodated substrate using the structures of some cnidarian Ca(2+)-regulated photoproteins with bound coelenterazine or coelenteramide as templates in order to obtain an adequate sampling and to take into account all possible conformers and variants for ligand-protein docking. Based on the impact of substitutions on the bioluminescent properties and model structures we speculate that within the internal cavity of ctenophore photoproteins, coelenterazine is bound as a 2-peroxy anion adduct which is stabilized owing to Coulomb interaction with a positively charged guanidinium group of Arg41 paired with Tyr204. In this case, the bioluminescence reaction is triggered by only calcium-induced conformational changes leading to the disturbance of charge-charge interaction.

  13. Equilibrium-based iterative tomography technique for soft x-ray in stellarators

    International Nuclear Information System (INIS)

    This paper reports on a method to deduce local values of plasma emissivity from chord measurements that has been developed and tested using data from a 30 detect or soft X-ray array in the Wendelstein 7A stellarator. This technique, based on the calculated distribution of toroidal magnetic flux as the initial guess for the plasma emissivity, uses an iterative scheme to determine algebraically the distribution of the detector signals, and solves some drawbackds of the currently available tomography techniques This method is especially adequate for stellarator devices where plasma cross sections are markedly noncircular and change as a function of the toroidal angle

  14. In-vivo retinal imaging by optical coherence tomography using an RSOD-based phase modulator

    Institute of Scientific and Technical Information of China (English)

    Ling WANG; Zhi-hua DING; Guo-hua SHI; Yu-dong ZHANG

    2009-01-01

    Fourier-domain rapid scanning optical delay line (RSOD) was introduced for phase modulation and depth scanning in a time-domain optical coherence tomography (TD-OCT) system. Investigation of parameter optimization of RSOD was conducted.Experiments for RSOD characterization at different parameters of the groove pitch, focal length, galvomirror size, etc. were performed. By implementing the optimized RSOD in our established TD-OCT system with a broadband light source centered at 840 nm with 50 nm bandwidth, in vivo retina imaging of a rabbit was presented, demonstrating the feasibility of high-quality TD-OCT imaging using an RSOD-based phase modulator.

  15. Element-sensitive computed tomography by fine tuning of PXR-based X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, Y., E-mail: yahayak@lebra.nihon-u.ac.jp [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Hayakawa, K.; Inagaki, M. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Kaneda, T. [Nihon University School of Dentistry at Matsudo, Sakaecho-Nishi 2-870-1, Matsudo 271-8587 (Japan); Nakao, K.; Nogami, K. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Sakae, T.; Sakai, T. [Nihon University School of Dentistry at Matsudo, Sakaecho-Nishi 2-870-1, Matsudo 271-8587 (Japan); Sato, I. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Takahashi, Y. [Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Oho, Tsukuba 305-8501 (Japan); Tanaka, T. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan)

    2015-07-15

    Element-sensitive computed tomography (CT) experiments were carried out based on the absorption edge of a specific element using a finely tunable X-ray beam generated by parametric X-ray radiation (PXR). Tomographic images of specimens containing strontium were measured at energies both lower and higher than that of the Sr absorption edge. The difference between the images of the two energies successfully reveals the three-dimensional distributions of Sr. The results demonstrate that this method is effective for elemental analysis of considerably thick samples and could complement X-ray fluorescence analysis.

  16. Volumetric Diffuse Optical Tomography for Small Animals Using a CCD-Camera-Based Imaging System

    Directory of Open Access Journals (Sweden)

    Zi-Jing Lin

    2012-01-01

    Full Text Available We report the feasibility of three-dimensional (3D volumetric diffuse optical tomography for small animal imaging by using a CCD-camera-based imaging system with a newly developed depth compensation algorithm (DCA. Our computer simulations and laboratory phantom studies have demonstrated that the combination of a CCD camera and DCA can significantly improve the accuracy in depth localization and lead to reconstruction of 3D volumetric images. This approach may present great interests for noninvasive 3D localization of an anomaly hidden in tissue, such as a tumor or a stroke lesion, for preclinical small animal models.

  17. Expression of a humanized viral 2A-mediated lux operon efficiently generates autonomous bioluminescence in human cells.

    Directory of Open Access Journals (Sweden)

    Tingting Xu

    Full Text Available Expression of autonomous bioluminescence from human cells was previously reported to be impossible, suggesting that all bioluminescent-based mammalian reporter systems must therefore require application of a potentially influential chemical substrate. While this was disproven when the bacterial luciferase (lux cassette was demonstrated to function in a human cell, its expression required multiple genetic constructs, was functional in only a single cell type, and generated a significantly reduced signal compared to substrate-requiring systems. Here we investigate the use of a humanized, viral 2A-linked lux genetic architecture for the efficient introduction of an autobioluminescent phenotype across a variety of human cell lines.The lux cassette was codon optimized and assembled into a synthetic human expression operon using viral 2A elements as linker regions. Human kidney, breast cancer, and colorectal cancer cell lines were both transiently and stably transfected with the humanized operon and the resulting autobioluminescent phenotype was evaluated using common imaging instrumentation. Autobioluminescent cells were screened for cytotoxic effects resulting from lux expression and their utility as bioreporters was evaluated through the demonstration of repeated monitoring of single populations over a prolonged period using both a modified E-SCREEN assay for estrogen detection and a classical cytotoxic compound detection assay for the antibiotic Zeocin. Furthermore, the use of self-directed bioluminescent initiation in response to target detection was assessed to determine its amenability towards deployment as fully autonomous sensors. In all cases, bioluminescent measurements were supported with traditional genetic and transcriptomic evaluations.Our results demonstrate that the viral 2A-linked, humanized lux genetic architecture successfully produced autobioluminescent phenotypes in all cell lines tested without the induction of cytotoxicity

  18. A causal relation between bioluminescence and oxygen to quantify the cell niche

    OpenAIRE

    Lambrechts, Dennis; Roeffaers, Maarten; Goossens, Karel; Hofkens, Johan; Vande Velde, Greetje; Van de Putte, Tom; Schrooten, Jan; Van Oosterwyck, Hans

    2014-01-01

    Bioluminescence imaging assays have become a widely integrated technique to quantify effectiveness of cell-based therapies by monitoring fate and survival of transplanted cells. To date these assays are still largely qualitative and often erroneous due to the complexity and dynamics of local micro-environments (niches) in which the cells reside. Here, we report, using a combined experimental and computational approach, on oxygen that besides being a critical niche component responsible for ce...

  19. Bioluminescence ATP Monitoring for the Routine Assessment of Food Contact Surface Cleanliness in a University Canteen

    OpenAIRE

    Andrea Osimani; Cristiana Garofalo; Francesca Clementi; Stefano Tavoletti; Lucia Aquilanti

    2014-01-01

    ATP bioluminescence monitoring and traditional microbiological analyses (viable counting of total mesophilic aerobes, coliforms and Escherichia coli) were used to evaluate the effectiveness of Sanitation Standard Operating Procedures (SSOP) at a university canteen which uses a HACCP-based approach. To that end, 10 cleaning control points (CPs), including food contact surfaces at risk of contamination from product residues or microbial growth, were analysed during an 8-month monitoring period....

  20. Construction of a bioluminescent reporter strain to detect polychlorinated biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Layton, A.C.; Muccini, M.; Ghosh, M.M.; Sayler, G.S. [Univ. of Tennessee, Knoxville, TN (United States)

    1998-12-01

    A bioluminescent reporter strain, Ralstonia eutropha ENV307 (pUTK60), was constructed for the detection of polychlorinated biphenyls by inserting the biphenyl promoter upstream of the bioluminescence genes. In the presence of a nonionic surfactant, which enhances the solubility of chlorinated biphenyls, bioluminescence was induced three- to fourfold over background by biphenyl, monochlorinated biphenyls, and Aroclor 1242. The minimum detection limits for these compounds ranged from 0.15 mg/liter for 4-chlorobiphenyl to 1.5 mg/liter for Aroclor 1242.

  1. Breast tumor segmentation in high resolution x-ray phase contrast analyzer based computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Brun, E., E-mail: emmanuel.brun@esrf.fr [European Synchrotron Radiation Facility (ESRF), Grenoble 380000, France and Department of Physics, Ludwig-Maximilians University, Garching 85748 (Germany); Grandl, S.; Sztrókay-Gaul, A.; Gasilov, S. [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377 Munich (Germany); Barbone, G. [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States); Mittone, A.; Coan, P. [Department of Physics, Ludwig-Maximilians University, Garching 85748, Germany and Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377 Munich (Germany); Bravin, A. [European Synchrotron Radiation Facility (ESRF), Grenoble 380000 (France)

    2014-11-01

    Purpose: Phase contrast computed tomography has emerged as an imaging method, which is able to outperform present day clinical mammography in breast tumor visualization while maintaining an equivalent average dose. To this day, no segmentation technique takes into account the specificity of the phase contrast signal. In this study, the authors propose a new mathematical framework for human-guided breast tumor segmentation. This method has been applied to high-resolution images of excised human organs, each of several gigabytes. Methods: The authors present a segmentation procedure based on the viscous watershed transform and demonstrate the efficacy of this method on analyzer based phase contrast images. The segmentation of tumors inside two full human breasts is then shown as an example of this procedure’s possible applications. Results: A correct and precise identification of the tumor boundaries was obtained and confirmed by manual contouring performed independently by four experienced radiologists. Conclusions: The authors demonstrate that applying the watershed viscous transform allows them to perform the segmentation of tumors in high-resolution x-ray analyzer based phase contrast breast computed tomography images. Combining the additional information provided by the segmentation procedure with the already high definition of morphological details and tissue boundaries offered by phase contrast imaging techniques, will represent a valuable multistep procedure to be used in future medical diagnostic applications.

  2. Bioluminescence of beetle luciferases with 6'-amino-D-luciferin analogues reveals excited keto-oxyluciferin as the emitter and phenolate/luciferin binding site interactions modulate bioluminescence colors.

    Science.gov (United States)

    Viviani, Vadim R; Neves, Deimison Rodrigues; Amaral, Danilo Trabuco; Prado, Rogilene A; Matsuhashi, Takuto; Hirano, Takashi

    2014-08-19

    Beetle luciferases produce different bioluminescence colors from green to red using the same d-luciferin substrate. Despite many studies of the mechanisms and structural determinants of bioluminescence colors with firefly luciferases, the identity of the emitters and the specific active site interactions responsible for bioluminescence color modulation remain elusive. To address these questions, we analyzed the bioluminescence spectra with 6'-amino-D-luciferin (aminoluciferin) and its 5,5-dimethyl analogue using a set of recombinant beetle luciferases that naturally elicit different colors and different pH sensitivities (pH-sensitive, Amydetes vivianii λmax=538 nm, Macrolampis sp2 λmax=564 nm; pH-insensitive, Phrixotrix hirtus λmax=623 nm, Phrixotrix vivianii λmax=546 nm, and Pyrearinus termitilluminans λmax=534 nm), a luciferase-like enzyme (Tenebrionidae, Zophobas morio λmax=613 nm), and mutants of C311 (S314). The green-yellow-emitting luciferases display red-shifted bioluminescence spectra with aminoluciferin in relation to those with D-luciferin, whereas the red-emitting luciferases displayed blue-shifted spectra. Bioluminescence spectra with 5,5-dimethylaminoluciferin, in which enolization is blocked, were almost identical to those of aminoluciferin. Fluorescence probing using 2-(4-toluidino)naphthalene-6-sulfonate and inference with aminoluciferin confirm that the luciferin binding site of the red-shifted luciferases is more polar than in the case of the green-yellow-emitting luciferases. Altogether, the results show that the keto form of excited oxyluciferin is the emitter in beetle bioluminescence and that bioluminescence colors are essentially modulated by interactions of the 6'-hydroxy group of oxyluciferin and basic moieties under the influence of the microenvironment polarity of the active site: a strong interaction between a base moiety and oxyluciferin phenol in a hydrophobic microenvironment promotes green-yellow emission, whereas a more polar

  3. Measuring IL-1β Processing by Bioluminescence Sensors I: Using a Bioluminescence Resonance Energy Transfer Biosensor.

    Science.gov (United States)

    Compan, Vincent; Pelegrín, Pablo

    2016-01-01

    IL-1β processing is one of the hallmarks of inflammasome activation and drives the initiation of the inflammatory response. For decades, Western blot or ELISA have been extensively used to study this inflammatory event. Here, we describe the use of a bioluminescence resonance energy transfer (BRET) biosensor to monitor IL-1β processing in real time and in living macrophages either using a plate reader or a microscope.

  4. Application of ATP-bioluminescence assay for screening chemotherapeutic agents of ovarian cancer chemotherapy

    International Nuclear Information System (INIS)

    To evaluate the feasibility of using ATP-bioluminescence assay for tumor chemosensitivity testing in vitro, authors selected the A2780 cell line as a model and established the suitable assay condition. Screening chemotherapeutic agents of ovarian cancer in vitro were preliminarily researched. Using this assay, dose-response curve was detected in cell line treated with these agents. The result showed that the coefficients of variation for assay ranged from 0.2% to 8.2%, which means high reproducibility. It can measured ATP content of as few as forty cells. The thermal stability of the luciferin-luciferase system was high enough used in industry. The predictable accuracy rate is about 90.6%. This study demonstrated ATP-bioluminescence assay is a reliable, reproducible and sensitive method. It can provide a technical base for screening sensitive chemotherapeutic agents in clinic

  5. Limited-angle tomography for analyzer-based phase-contrast x-ray imaging

    International Nuclear Information System (INIS)

    Multiple-image radiography (MIR) is an analyzer-based phase-contrast x-ray imaging method, which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT

  6. Limited-angle tomography for analyzer-based phase-contrast x-ray imaging

    Science.gov (United States)

    Majidi, Keivan; Wernick, Miles N.; Li, Jun; Muehleman, Carol; Brankov, Jovan G.

    2014-07-01

    Multiple-image radiography (MIR) is an analyzer-based phase-contrast x-ray imaging method, which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT

  7. Bioluminescence : the potential of a non-invasive bio-optical imaging technique and improvement of animal research

    NARCIS (Netherlands)

    Hesselink, J. W.; van Dam, G. M.

    2007-01-01

    Bioluminescence is an optical imaging technique that exploits the emission of photons at specific wavelengths based on energy-dependent reactions catalysed by luciferases. The technique makes it possible to monitor measure, and track biological processes in living animals. A short review is presente

  8. Probing intermolecular protein-protein interactions in the calcium-sensing receptor homodimer using bioluminescence resonance energy transfer (BRET)

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Hansen, Jakob L; Sheikh, Søren P;

    2002-01-01

    -induced intermolecular movements in the CaR homodimer using the new bioluminescence resonance energy transfer technique, BRET2, which is based on the transference of energy from Renilla luciferase (Rluc) to the green fluorescent protein mutant GFP2. We tagged CaR with Rluc and GFP2 at different intracellular locations...

  9. Draft genome sequence of the polycyclic aromatic hydrocarbon-degrading, genetically engineered bioluminescent bioreporter Pseudomonas fluorescens HK44.

    Science.gov (United States)

    Chauhan, Archana; Layton, Alice C; Williams, Daniel E; Smartt, Abby E; Ripp, Steven; Karpinets, Tatiana V; Brown, Steven D; Sayler, Gary S

    2011-09-01

    Pseudomonas fluorescens strain HK44 (DSM 6700) is a genetically engineered lux-based bioluminescent bioreporter. Here we report the draft genome sequence of strain HK44. Annotation of ∼6.1 Mb of sequence indicates that 30% of the traits are unique and distributed over five genomic islands, a prophage, and two plasmids.

  10. Draft Genome Sequence of the Polycyclic Aromatic Hydrocarbon-Degrading, Genetically Engineered Bioluminescent Bioreporter Pseudomonas fluorescens HK44

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Archana [ORNL; Layton, Alice [University of Tennessee, Knoxville (UTK); Williams, Daniel W [ORNL; Smart, Abby E. [University of Tennessee, Knoxville (UTK); Ripp, Steven Anthony [ORNL; Karpinets, Tatiana V [ORNL; Brown, Steven D [ORNL; Sayler, Gary Steven [ORNL

    2011-01-01

    Pseudomonas fluorescens strain HK44 (DSM 6700) is a genetically engineered lux-based bioluminescent bioreporter. Here we report the draft genome sequence of strain HK44. Annotation of {approx}6.1 Mb sequence indicates that 30% of the traits are unique and distributed over 5 genomic islands, a prophage and two plasmids.

  11. Grating-based X-ray Dark-field Computed Tomography of Living Mice

    Directory of Open Access Journals (Sweden)

    A. Velroyen

    2015-10-01

    Full Text Available Changes in x-ray attenuating tissue caused by lung disorders like emphysema or fibrosis are subtle and thus only resolved by high-resolution computed tomography (CT. The structural reorganization, however, is of strong influence for lung function. Dark-field CT (DFCT, based on small-angle scattering of x-rays, reveals such structural changes even at resolutions coarser than the pulmonary network and thus provides access to their anatomical distribution. In this proof-of-concept study we present x-ray in vivo DFCTs of lungs of a healthy, an emphysematous and a fibrotic mouse. The tomographies show excellent depiction of the distribution of structural – and thus indirectly functional – changes in lung parenchyma, on single-modality slices in dark field as well as on multimodal fusion images. Therefore, we anticipate numerous applications of DFCT in diagnostic lung imaging. We introduce a scatter-based Hounsfield Unit (sHU scale to facilitate comparability of scans. In this newly defined sHU scale, the pathophysiological changes by emphysema and fibrosis cause a shift towards lower numbers, compared to healthy lung tissue.

  12. Voxel based morphometry in optical coherence tomography: validation and core findings

    Science.gov (United States)

    Antony, Bhavna J.; Chen, Min; Carass, Aaron; Jedynak, Bruno M.; Al-Louzi, Omar; Solomon, Sharon D.; Saidha, Shiv; Calabresi, Peter A.; Prince, Jerry L.

    2016-03-01

    Optical coherence tomography (OCT) of the human retina is now becoming established as an important modality for the detection and tracking of various ocular diseases. Voxel based morphometry (VBM) is a long standing neuroimaging analysis technique that allows for the exploration of the regional differences in the brain. There has been limited work done in developing registration based methods for OCT, which has hampered the advancement of VBM analyses in OCT based population studies. Following on from our recent development of an OCT registration method, we explore the potential benefits of VBM analysis in cohorts of healthy controls (HCs) and multiple sclerosis (MS) patients. Specifically, we validate the stability of VBM analysis in two pools of HCs showing no significant difference between the two populations. Additionally, we also present a retrospective study of age and sex matched HCs and relapsing remitting MS patients, demonstrating results consistent with the reported literature while providing insight into the retinal changes associated with this MS subtype.

  13. 3-D Adaptive Sparsity Based Image Compression With Applications to Optical Coherence Tomography.

    Science.gov (United States)

    Fang, Leyuan; Li, Shutao; Kang, Xudong; Izatt, Joseph A; Farsiu, Sina

    2015-06-01

    We present a novel general-purpose compression method for tomographic images, termed 3D adaptive sparse representation based compression (3D-ASRC). In this paper, we focus on applications of 3D-ASRC for the compression of ophthalmic 3D optical coherence tomography (OCT) images. The 3D-ASRC algorithm exploits correlations among adjacent OCT images to improve compression performance, yet is sensitive to preserving their differences. Due to the inherent denoising mechanism of the sparsity based 3D-ASRC, the quality of the compressed images are often better than the raw images they are based on. Experiments on clinical-grade retinal OCT images demonstrate the superiority of the proposed 3D-ASRC over other well-known compression methods. PMID:25561591

  14. Accounting for systematic errors in bioluminescence imaging to improve quantitative accuracy

    Science.gov (United States)

    Taylor, Shelley L.; Perry, Tracey A.; Styles, Iain B.; Cobbold, Mark; Dehghani, Hamid

    2015-07-01

    Bioluminescence imaging (BLI) is a widely used pre-clinical imaging technique, but there are a number of limitations to its quantitative accuracy. This work uses an animal model to demonstrate some significant limitations of BLI and presents processing methods and algorithms which overcome these limitations, increasing the quantitative accuracy of the technique. The position of the imaging subject and source depth are both shown to affect the measured luminescence intensity. Free Space Modelling is used to eliminate the systematic error due to the camera/subject geometry, removing the dependence of luminescence intensity on animal position. Bioluminescence tomography (BLT) is then used to provide additional information about the depth and intensity of the source. A substantial limitation in the number of sources identified using BLI is also presented. It is shown that when a given source is at a significant depth, it can appear as multiple sources when imaged using BLI, while the use of BLT recovers the true number of sources present.

  15. Bioluminescence-activated deep-tissue photodynamic therapy of cancer.

    Science.gov (United States)

    Kim, Yi Rang; Kim, Seonghoon; Choi, Jin Woo; Choi, Sung Yong; Lee, Sang-Hee; Kim, Homin; Hahn, Sei Kwang; Koh, Gou Young; Yun, Seok Hyun

    2015-01-01

    Optical energy can trigger a variety of photochemical processes useful for therapies. Owing to the shallow penetration of light in tissues, however, the clinical applications of light-activated therapies have been limited. Bioluminescence resonant energy transfer (BRET) may provide a new way of inducing photochemical activation. Here, we show that efficient bioluminescence energy-induced photodynamic therapy (PDT) of macroscopic tumors and metastases in deep tissue. For monolayer cell culture in vitro incubated with Chlorin e6, BRET energy of about 1 nJ per cell generated as strong cytotoxicity as red laser light irradiation at 2.2 mW/cm(2) for 180 s. Regional delivery of bioluminescence agents via draining lymphatic vessels killed tumor cells spread to the sentinel and secondary lymph nodes, reduced distant metastases in the lung and improved animal survival. Our results show the promising potential of novel bioluminescence-activated PDT.

  16. Bioluminescence: a versatile technique for imaging cellular and molecular features

    Science.gov (United States)

    Paley, Miranda A.

    2016-01-01

    Bioluminescence is a ubiquitous imaging modality for visualizing biological processes in vivo. This technique employs visible light and interfaces readily with most cell and tissue types, making it a versatile technology for preclinical studies. Here we review basic bioluminescence imaging principles, along with applications of the technology that are relevant to the medicinal chemistry community. These include noninvasive cell tracking experiments, analyses of protein function, and methods to visualize small molecule metabolites. In each section, we also discuss how bioluminescent tools have revealed insights into experimental therapies and aided drug discovery. Last, we highlight the development of new bioluminescent tools that will enable more sensitive and multi-component imaging experiments and, thus, expand our broader understanding of living systems.

  17. The terrestrial bioluminescent animals of Japan.

    Science.gov (United States)

    Oba, Yuichi; Branham, Marc A; Fukatsu, Takema

    2011-11-01

    Light production by organisms, or bioluminescence, has fascinated not only scientists but also ordinary people all over the world, and it has been especially so in Japan. Here we review the biological information available to date for all luminous terrestrial animals known from Japan, particularly focusing on their diversity and systematics, their biology and ecology in Japan, and putative function and biochemistry of their luminescence. In total 58 luminous terrestrial animals have been described from Japan, which consist of 50 fireflies (Coleoptera: Lampyridae), one glowworm beetle (Coleoptera: Phengodidae), two fungus gnats (Diptera: Keroplatidae), one springtail (Collembola), one millipede (Diplopoda), one centipede (Chilopoda) and two earthworms (Oligochaeta). For all except some firefly species, the DNA "barcode" sequences of a cytochrome oxidase subunit I region are provided. We also introduce how intricately the seasonal appearance and glimmering of luminous insects, in particular those of fireflies, have been interwoven into the culture, art, literature and mentality of Japanese people. PMID:22035300

  18. Dinoflagellate bioluminescence in response to mechanical stimuli in water flows

    OpenAIRE

    Cussatlegras, A. S.; Gal, P.

    2005-01-01

    International audience Bioluminescence of plankton organisms induced by water movements has long been observed and is still under investigations because of its great complexity. In particular, the exact mechanism occurring at the level of the cell has not been yet fully understood. This work is devoted to the study of the bioluminescence of the dinoflagellates plankton species Pyrocystis noctiluca in response to mechanical stimuli generated by water flows. Several experiments were performe...

  19. Shedding light on bioluminescence regulation in Vibrio fischeri

    OpenAIRE

    Miyashiro, Tim; Ruby, Edward G.

    2012-01-01

    The bioluminescence emitted by the marine bacterium Vibrio fischeri is a particularly striking result of individual microbial cells coordinating a group behavior. The genes responsible for light production are principally regulated by the LuxR-LuxI quorum-sensing system. In addition to LuxR-LuxI, numerous other genetic elements and environmental conditions control bioluminescence production. Efforts to mathematically model the LuxR-LuxI system are providing insight into the dynamics of this a...

  20. Bioluminescence Imaging of Chlamydia muridarum Ascending Infection in Mice

    OpenAIRE

    Jessica Campbell; Yumeng Huang; Yuanjun Liu; Robert Schenken; Bernard Arulanandam; Guangming Zhong

    2014-01-01

    Chlamydial pathogenicity in the upper genital tract relies on chlamydial ascending from the lower genital tract. To monitor chlamydial ascension, we engineered a luciferase-expressing C. muridarum. In cells infected with the luciferase-expressing C. muridarum, luciferase gene expression and enzymatic activity (measured as bioluminescence intensity) correlated well along the infection course, suggesting that bioluminescence can be used for monitoring chlamydial replication. Following an intrav...

  1. Bioluminescence-Sensing Assay for Microbial Growth Recognition

    OpenAIRE

    Heba Ramadan Eed; Abdel-Kader, Nora S.; Mahmoud Helmy El Tahan; Tianhong Dai; Rehab Amin

    2016-01-01

    The conventional methods for microbial viability quantification require cultivation and are laborious. There is consequently a widespread need for cultivation-free methods. The adenosine triphosphate (ATP) bioluminescence-sensing assay is considered an extremely effective biosensor; hence ATP is the energy currency of all living microbes and can be used as a rapid indicator of microbial viability. We developed an ATP bioluminescence-sensing assay to detect microbial viability. A biolumine...

  2. Circadian regulation of bioluminescence in Gonyaulax involves translational control.

    OpenAIRE

    Morse, D.; Milos, P M; Roux, E.; Hastings, J. W.

    1989-01-01

    A 10-fold circadian variation in the amount of luciferin binding protein (LBP) in the marine dinoflagellate Gonyaulax polyedra is reported. This protein binds and stabilizes luciferin, the bioluminescence substrate. In early night phase, when bioluminescence is increasing and LBP levels are rising in the cell, pulse labeling experiments show that LBP is being rapidly synthesized in vivo. At other times, the rate of LBP synthesis is at least 50 times lower, while the rate of synthesis of most ...

  3. Action of γ-radiation on bioluminescence of Noctiluca miliaris

    International Nuclear Information System (INIS)

    Results of the study in the action of various doses of irradiation on the bioluminescence of Noctiluca miliaris are presented. The doses are found that stimulate the bioluminescence and the dose - effect curves are obtained. It has been shown that stimulation of Noctiluca luminescence by γ-radiation is not of a constant character and extinguishes after a period of time determined by a dose rate

  4. Bioluminescence in dinoflagellates – diversity, molecular phylogeny and field ecology

    OpenAIRE

    Valiadi, Martha

    2011-01-01

    Marine dinoflagellates are an ecologically important group of protists within the plankton, performing key process such as photosynthesis, heterotrophy and toxin production. Some dinoflagellates are also capable of producing bioluminescence and they are the most abundant protists that produce light in the surface waters of the oceans. This study employed molecular tools to investigate the identity of bioluminescent species, the genetic basis, diversity and functional regulation of biolumin...

  5. Interactive graphic editing tools in bioluminescent imaging simulation

    Science.gov (United States)

    Li, Hui; Tian, Jie; Luo, Jie; Wang, Ge; Cong, Wenxiang

    2005-04-01

    It is a challenging task to accurately describe complicated biological tissues and bioluminescent sources in bioluminescent imaging simulation. Several graphic editing tools have been developed to efficiently model each part of the bioluminescent simulation environment and to interactively correct or improve the initial models of anatomical structures or bioluminescent sources. There are two major types of graphic editing tools: non-interactive tools and interactive tools. Geometric building blocks (i.e. regular geometric graphics and superquadrics) are applied as non-interactive tools. To a certain extent, complicated anatomical structures and bioluminescent sources can be approximately modeled by combining a sufficient large number of geometric building blocks with Boolean operators. However, those models are too simple to describe the local features and fine changes in 2D/3D irregular contours. Therefore, interactive graphic editing tools have been developed to facilitate the local modifications of any initial surface model. With initial models composed of geometric building blocks, interactive spline mode is applied to conveniently perform dragging and compressing operations on 2D/3D local surface of biological tissues and bioluminescent sources inside the region/volume of interest. Several applications of the interactive graphic editing tools will be presented in this article.

  6. Bioluminescence imaging of Chlamydia muridarum ascending infection in mice.

    Science.gov (United States)

    Campbell, Jessica; Huang, Yumeng; Liu, Yuanjun; Schenken, Robert; Arulanandam, Bernard; Zhong, Guangming

    2014-01-01

    Chlamydial pathogenicity in the upper genital tract relies on chlamydial ascending from the lower genital tract. To monitor chlamydial ascension, we engineered a luciferase-expressing C. muridarum. In cells infected with the luciferase-expressing C. muridarum, luciferase gene expression and enzymatic activity (measured as bioluminescence intensity) correlated well along the infection course, suggesting that bioluminescence can be used for monitoring chlamydial replication. Following an intravaginal inoculation with the luciferase-expressing C. muridarum, 8 of 10 mice displayed bioluminescence signal in the lower with 4 also in the upper genital tracts on day 3 after infection. By day 7, all 10 mice developed bioluminescence signal in the upper genital tracts. The bioluminescence signal was maintained in the upper genital tract in 6 and 2 mice by days 14 and 21, respectively. The bioluminescence signal was no longer detectable in any of the mice by day 28. The whole body imaging approach also revealed an unexpected airway infection following the intravaginal inoculation. Although the concomitant airway infection was transient and did not significantly alter the genital tract infection time courses, caution should be taken during data interpretation. The above observations have demonstrated that C. muridarum can not only achieve rapid ascending infection in the genital tract but also cause airway infection following a genital tract inoculation. These findings have laid a foundation for further optimizing the C. muridarum intravaginal infection murine model for understanding chlamydial pathogenic mechanisms.

  7. Stimulation of bioluminescence in Noctiluca sp. using controlled temperature changes.

    Science.gov (United States)

    Han, Jing; Li, GuiJuan; Liu, HuanYing; Hu, HaoHao; Zhang, XueGang

    2013-01-01

    Bioluminescence induced by multifarious stimuli has long been observed and is remains under investigation because of its great complexity. In particular, the exact mechanism underlying bioluminescence is not yet fully understood. This work presents a new experimental method for studying Noctiluca sp. bioluminescence under temperature change stimulation. It is a study of Noctiluca sp. bioluminescence using controlled temperature changes in a tank. A characteristic of this experiment is the large volume of water used (1 m(3) in a tank of 2 × 1 × 1 m). Temperature changes were controlled by two methods. In the first, a flask filled with hot water was introduced into the tank and in the second, a water heater was used in the tank. Temperature changes were recorded using sensors. Noctiluca sp. bioluminescence was recorded using a Canon 5D Mark II and this allowed the characteristics of Noctiluca sp. bioluminescence under temperature change stimulation to be monitored.

  8. Bioluminescence imaging of Chlamydia muridarum ascending infection in mice.

    Directory of Open Access Journals (Sweden)

    Jessica Campbell

    Full Text Available Chlamydial pathogenicity in the upper genital tract relies on chlamydial ascending from the lower genital tract. To monitor chlamydial ascension, we engineered a luciferase-expressing C. muridarum. In cells infected with the luciferase-expressing C. muridarum, luciferase gene expression and enzymatic activity (measured as bioluminescence intensity correlated well along the infection course, suggesting that bioluminescence can be used for monitoring chlamydial replication. Following an intravaginal inoculation with the luciferase-expressing C. muridarum, 8 of 10 mice displayed bioluminescence signal in the lower with 4 also in the upper genital tracts on day 3 after infection. By day 7, all 10 mice developed bioluminescence signal in the upper genital tracts. The bioluminescence signal was maintained in the upper genital tract in 6 and 2 mice by days 14 and 21, respectively. The bioluminescence signal was no longer detectable in any of the mice by day 28. The whole body imaging approach also revealed an unexpected airway infection following the intravaginal inoculation. Although the concomitant airway infection was transient and did not significantly alter the genital tract infection time courses, caution should be taken during data interpretation. The above observations have demonstrated that C. muridarum can not only achieve rapid ascending infection in the genital tract but also cause airway infection following a genital tract inoculation. These findings have laid a foundation for further optimizing the C. muridarum intravaginal infection murine model for understanding chlamydial pathogenic mechanisms.

  9. Wave equation-based reflection tomography of the 1992 Landers earthquake area

    Science.gov (United States)

    Huang, Xueyuan; Yang, Dinghui; Tong, Ping; Badal, José; Liu, Qinya

    2016-03-01

    In the framework of a recent wave equation-based traveltime seismic tomography, we show that incorporating Moho-reflected phases (PmP and SmS) in addition to the direct P and S phases can significantly increase tomography resolution in the lower crust and this may provide additional evidence to resolve important tectonic issues. To highlight the resolving power of the new strategy, we apply it in the region around the 1992 Landers earthquake (Mw = 7.3) in Southern California using seismic arrivals from local earthquakes, obtaining 3-D high-resolution P and S wave crustal velocity models and Poisson's ratio structures. In the upper crust, our method confirmed features that had been previously found. However, in the middle-to-lower crust, we found low-velocity anomalies on the southeastern section of the San Jacinto Fault and high Vp and low Vs structures to the west of the Big Bear earthquake, which may be related to upwelling of partial melt from the mantle.

  10. Surface and subsurface damage detection in cement-based materials using electrical resistance tomography

    Science.gov (United States)

    Ruan, T.; Poursaee, A.

    2016-04-01

    Cement-based materials are widely used in infrastructure facilities. However, often the degradation of structures leads to the failures earlier than designed service life. Thus, non-destructive testing techniques are urgently needed to evaluate the health information of the structures. In this paper, the implementation of Electrical Resistance Tomography (ERT) was investigated. This low cost, radiation free and easy to perform modality is based on measuring the electrical properties of the material under test and using that to evaluate the existence of defects in that material. It uses a set of boundary potentials and injected current to reconstruct the conductivity distribution. An automatic measurement system was developed and surface damages as well as subsurface damages on mortar specimens were investigated. The reconstructed images were capable to show the presence and the location of the damages.

  11. Common-path optical coherence tomography using a microelectromechanical-system-based endoscopic probe.

    Science.gov (United States)

    Wang, Donglin; Duan, Can; Zhang, Xiaoyang; Yun, Zhao; Pozzi, Antonio; Xie, Huikai

    2016-09-01

    This paper presents a common-path (CP) swept-source optical coherence tomography (SSOCT) system based on a special endoscopic probe design with an in-line internal reflection as the reference and a two-axis electrothermal microelectromechanical system mirror for image scanning. The rear surface of a gradient reflective index (GRIN) lens inside the probe is set as the reference reflection plane. The length of the GRIN lens is optimized to eliminate the artifacts in SSOCT images successfully. Doppler OCT is also demonstrated based on the CP endoscopic probe. The diameter of the probe is only 2.5 mm, so it can be easily inserted into the biopsy channel of traditional endoscopes to access human internal organs for in vivo diagnoses. PMID:27607267

  12. Stabilizing dual-energy X-ray computed tomography reconstructions using patch-based regularization

    CERN Document Server

    Tracey, Brian H

    2014-01-01

    Recent years have seen growing interest in exploiting dual- and multi-energy measurements in computed tomography (CT) in order to characterize material properties as well as object shape. Material characterization is performed by decomposing the scene into constitutive basis functions, such as Compton scatter and photoelectric absorption functions. While well motivated physically, the joint recovery of the spatial distribution of photoelectric and Compton properties is severely complicated by the fact that the data are several orders of magnitude more sensitive to Compton scatter coefficients than to photoelectric absorption, so small errors in Compton estimates can create large artifacts in the photoelectric estimate. To address these issues, we propose a model-based iterative approach which uses patch-based regularization terms to stabilize inversion of photoelectric coefficients, and solve the resulting problem though use of computationally attractive Alternating Direction Method of Multipliers (ADMM) solu...

  13. A fast marching method based back projection algorithm for photoacoustic tomography in heterogeneous media

    CERN Document Server

    Wang, Tianren

    2015-01-01

    This paper presents a numerical study on a fast marching method based back projection reconstruction algorithm for photoacoustic tomography in heterogeneous media. Transcranial imaging is used here as a case study. To correct for the phase aberration from the heterogeneity (i.e., skull), the fast marching method is adopted to compute the phase delay based on the known speed of sound distribution, and the phase delay is taken into account by the back projection algorithm for more accurate reconstructions. It is shown that the proposed algorithm is more accurate than the conventional back projection algorithm, but slightly less accurate than the time reversal algorithm particularly in the area close to the skull. However, the image reconstruction time for the proposed algorithm can be as little as 124 ms when implemented by a GPU (512 sensors, 21323 pixels reconstructed), which is two orders of magnitude faster than the time reversal reconstruction. The proposed algorithm, therefore, not only corrects for the p...

  14. Bathyphotometer bioluminescence potential measurements: A framework for characterizing flow agitators and predicting flow-stimulated bioluminescence intensity

    Science.gov (United States)

    Latz, Michael I.; Rohr, Jim

    2013-07-01

    Bathyphotometer measurements of bioluminescence are used as a proxy for the abundance of luminescent organisms for studying population dynamics; the interaction of luminescent organisms with physical, chemical, and biological oceanographic processes; and spatial complexity especially in coastal areas. However, the usefulness of bioluminescence measurements has been limited by the inability to compare results from different bathyphotometer designs, or even the same bathyphotometer operating at different volume flow rates. The primary objective of this study was to compare measurements of stimulated bioluminescence of four species of cultured dinoflagellates, the most common source of bioluminescence in coastal waters, using two different bathyphotometer flow agitators as a function of bathyphotometer volume flow rate and dinoflagellate concentration. For both the NOSC and BIOLITE flow agitators and each species of dinoflagellate tested, there was a critical volume flow rate, above which average bioluminescence intensity, designated as bathyphotometer bioluminescence potential (BBP), remained relatively constant and scaled directly with dinoflagellate cell concentration. At supra-critical volume flow rates, the ratio of BIOLITE to NOSC BBP was nearly constant for the same species studied, but varied between species. The spatial pattern and residence time of flash trajectories within the NOSC flow agitator indicated the presence of dominant secondary recirculating flows, where most of the bioluminescence was detected. A secondary objective (appearing in the Appendix) was to study the feasibility of using NOSC BBP to scale flow-stimulated bioluminescence intensity across similar flow fields, where the contributing composition of luminescent species remained the same. Fully developed turbulent pipe flow was chosen because it is hydrodynamically well characterized. Average bioluminescence intensity in a 2.54-cm i.d. pipe was highly correlated with wall shear stress and

  15. An ebCMOS camera system for marine bioluminescence observation: The LuSEApher prototype

    Energy Technology Data Exchange (ETDEWEB)

    Dominjon, A., E-mail: a.dominjon@ipnl.in2p3.fr [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Ageron, M. [CNRS/IN2P3, Centre de Physique des Particules de Marseille, Marseille, F-13288 (France); Barbier, R. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Universite de Lyon, Universite Lyon 1, Lyon F-69003 (France); Billault, M.; Brunner, J. [CNRS/IN2P3, Centre de Physique des Particules de Marseille, Marseille, F-13288 (France); Cajgfinger, T. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Universite de Lyon, Universite Lyon 1, Lyon F-69003 (France); Calabria, P. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Chabanat, E. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Universite de Lyon, Universite Lyon 1, Lyon F-69003 (France); Chaize, D.; Doan, Q.T.; Guerin, C.; Houles, J.; Vagneron, L. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France)

    2012-12-11

    The ebCMOS camera, called LuSEApher, is a marine bioluminescence recorder device adapted to extreme low light level. This prototype is based on the skeleton of the LUSIPHER camera system originally developed for fluorescence imaging. It has been installed at 2500 m depth off the Mediterranean shore on the site of the ANTARES neutrino telescope. The LuSEApher camera is mounted on the Instrumented Interface Module connected to the ANTARES network for environmental science purposes (European Seas Observatory Network). The LuSEApher is a self-triggered photo detection system with photon counting ability. The presentation of the device is given and its performances such as the single photon reconstruction, noise performances and trigger strategy are presented. The first recorded movies of bioluminescence are analyzed. To our knowledge, those types of events have never been obtained with such a sensitivity and such a frame rate. We believe that this camera concept could open a new window on bioluminescence studies in the deep sea.

  16. Using bacterial bioluminescence to evaluate the impact of biofilm on porous media hydraulic properties.

    Science.gov (United States)

    Bozorg, Ali; Gates, Ian D; Sen, Arindom

    2015-02-01

    Biofilm formation in natural and engineered porous systems can significantly impact hydrodynamics by reducing porosity and permeability. To better understand and characterize how biofilms influence hydrodynamic properties in porous systems, the genetically engineered bioluminescent bacterial strain Pseudomonas fluorescens HK44 was used to quantify microbial population characteristics and biofilm properties in a translucent porous medium. Power law relationships were found to exist between bacterial bioluminescence and cell density, fraction of void space occupied by biofilm (i.e. biofilm saturation), and hydraulic conductivity. The simultaneous evaluation of biofilm saturation and porous medium hydraulic conductivity in real time using a non-destructive approach enabled the construction of relative hydraulic conductivity curves. Such information can facilitate simulation studies related to biological activity in porous structures, and support the development of new models to describe the dynamic behavior of biofilm and fluid flow in porous media. The bioluminescence based approach described here will allow for improved understanding and control of industrially relevant processes such as biofiltration and bioremediation. PMID:25479429

  17. An ebCMOS camera system for marine bioluminescence observation: The LuSEApher prototype

    International Nuclear Information System (INIS)

    The ebCMOS camera, called LuSEApher, is a marine bioluminescence recorder device adapted to extreme low light level. This prototype is based on the skeleton of the LUSIPHER camera system originally developed for fluorescence imaging. It has been installed at 2500 m depth off the Mediterranean shore on the site of the ANTARES neutrino telescope. The LuSEApher camera is mounted on the Instrumented Interface Module connected to the ANTARES network for environmental science purposes (European Seas Observatory Network). The LuSEApher is a self-triggered photo detection system with photon counting ability. The presentation of the device is given and its performances such as the single photon reconstruction, noise performances and trigger strategy are presented. The first recorded movies of bioluminescence are analyzed. To our knowledge, those types of events have never been obtained with such a sensitivity and such a frame rate. We believe that this camera concept could open a new window on bioluminescence studies in the deep sea.

  18. Fast monitoring of indoor bioaerosol concentrations with ATP bioluminescence assay using an electrostatic rod-type sampler.

    Science.gov (United States)

    Park, Ji-Woon; Park, Chul Woo; Lee, Sung Hwa; Hwang, Jungho

    2015-01-01

    A culture-based colony counting method is the most widely used analytical technique for monitoring bioaerosols in both indoor and outdoor environments. However, this method requires several days for colony formation. In this study, our goal was fast monitoring (Sampling: 3 min, Detection: bioluminescence assay using a bioaerosol sampler. For this purpose, a novel hand-held electrostatic rod-type sampler (110 mm wide, 115 mm long, and 200 mm tall) was developed and used with a commercial luminometer, which employs the Adenosine triphosphate (ATP) bioluminescence method. The sampler consisted of a wire-rod type charger and a cylindrical collector, and was operated with an applied voltage of 4.5 kV and a sampling flow rate of 150.7 lpm. Its performance was tested using Staphylococcus epidermidis which was aerosolized with an atomizer. Bioaerosol concentrations were measured using ATP bioluminescence method with our sampler and compared with the culture-based method using Andersen cascade impactor under controlled laboratory conditions. Indoor bioaerosol concentrations were also measured using both methods in various indoor environments. A linear correlation was obtained between both methods in lab-tests and field-tests. Our proposed sampler with ATP bioluminescence method may be effective for fast monitoring of indoor bioaerosol concentrations.

  19. Fast monitoring of indoor bioaerosol concentrations with ATP bioluminescence assay using an electrostatic rod-type sampler.

    Directory of Open Access Journals (Sweden)

    Ji-Woon Park

    Full Text Available A culture-based colony counting method is the most widely used analytical technique for monitoring bioaerosols in both indoor and outdoor environments. However, this method requires several days for colony formation. In this study, our goal was fast monitoring (Sampling: 3 min, Detection: < 1 min of indoor bioaerosol concentrations with ATP bioluminescence assay using a bioaerosol sampler. For this purpose, a novel hand-held electrostatic rod-type sampler (110 mm wide, 115 mm long, and 200 mm tall was developed and used with a commercial luminometer, which employs the Adenosine triphosphate (ATP bioluminescence method. The sampler consisted of a wire-rod type charger and a cylindrical collector, and was operated with an applied voltage of 4.5 kV and a sampling flow rate of 150.7 lpm. Its performance was tested using Staphylococcus epidermidis which was aerosolized with an atomizer. Bioaerosol concentrations were measured using ATP bioluminescence method with our sampler and compared with the culture-based method using Andersen cascade impactor under controlled laboratory conditions. Indoor bioaerosol concentrations were also measured using both methods in various indoor environments. A linear correlation was obtained between both methods in lab-tests and field-tests. Our proposed sampler with ATP bioluminescence method may be effective for fast monitoring of indoor bioaerosol concentrations.

  20. Multi-phase flow monitoring with electrical impedance tomography using level set based method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dong [Department of Applied Physics, University of Eastern Finland, Kuopio FIN-70211 (Finland); Khambampati, Anil Kumar [Institute for Nuclear Science and Technology, Jeju National University, Jeju 690-756 (Korea, Republic of); Kim, Sin [School of Energy Systems Engineering, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Kim, Kyung Youn, E-mail: kyungyk@jejunu.ac.kr [Department of Electronic Engineering, Jeju National University, Jeju 690-756 (Korea, Republic of)

    2015-08-15

    Highlights: • LSM has been used for shape reconstruction to monitor multi-phase flow using EIT. • Multi-phase level set model for conductivity is represented by two level set functions. • LSM handles topological merging and breaking naturally during evolution process. • To reduce the computational time, a narrowband technique was applied. • Use of narrowband and optimization approach results in efficient and fast method. - Abstract: In this paper, a level set-based reconstruction scheme is applied to multi-phase flow monitoring using electrical impedance tomography (EIT). The proposed scheme involves applying a narrowband level set method to solve the inverse problem of finding the interface between the regions having different conductivity values. The multi-phase level set model for the conductivity distribution inside the domain is represented by two level set functions. The key principle of the level set-based method is to implicitly represent the shape of interface as the zero level set of higher dimensional function and then solve a set of partial differential equations. The level set-based scheme handles topological merging and breaking naturally during the evolution process. It also offers several advantages compared to traditional pixel-based approach. Level set-based method for multi-phase flow is tested with numerical and experimental data. It is found that level set-based method has better reconstruction performance when compared to pixel-based method.

  1. Skull base osteomyelitis in otitis externa: The utility of triphasic and single photon emission computed tomography/computed tomography bone scintigraphy

    International Nuclear Information System (INIS)

    Skull base osteomyelitis (SBO) refers to infection that has spread beyond the external auditory canal to the base of the skull in advanced stages of otitis externa. Clinically, it may be difficult to differentiate SBO from severe otitis externa without bony involvement. This study was performed to determine the role of three phase bone scintigraphy (TPBS) and single photon emission tomography/computed tomography (SPECT/CT) in detecting SBO. We retrospectively analyzed records of 20 patients (14 M, 6 F) with otitis externa and suspected SBO. TPBS and SPECT/CT of the skull were performed. Findings were correlated with clinical, laboratory and diagnostic CT scan findings. All patients were diabetic with elevated erythrocyte sedimentation rate. A total of 18 patients had bilateral and two unilateral symptoms. Cranial nerves were involved in eight patients and microbiological culture of ear discharge fluid positive in seven. Early images showed increased temporal vascularity in nine patients and increased soft-tissue uptake in 10, while delayed images showed increased bone uptake in 19/20 patients. Localized abnormal tracer uptake was shown by SPECT/CT in the mastoid temporal (15), petrous (11), sphenoid (3) and zygomatic (1) and showed destructive changes in five. Thus, TPBS was found positive for SBO in 10/20 patients and changed the management in four. Our study suggests that TPBS with SPECT/CT is a useful non-invasive investigation for detection of SBO in otitis externa

  2. In vivo microwave-based thermoacoustic tomography of rats (Conference Presentation)

    Science.gov (United States)

    Lin, Li; Zhou, Yong; Wang, Lihong V.

    2016-03-01

    Microwave-based thermoacoustic tomography (TAT), based on the measurement of ultrasonic waves induced by microwave pulses, can reveal tissue dielectric properties that may be closely related to the physiological and pathological status of the tissues. Using microwaves as the excitation source improved imaging depth because of their deep penetration into biological tissues. We demonstrate, for the first time, in vivo microwave-based thermoacoustic imaging in rats. The transducer is rotated around the rat in a full circle, providing a full two-dimensional view. Instead of a flat ultrasonic transducer, we used a virtual line detector based on a cylindrically focused transducer. A 3 GHz microwave source with 0.6 µs pulse width and an electromagnetically shielded transducer with 2.25 MHz central frequency provided clear cross-sectional images of the rat's body. The high imaging contrast, based on the tissue's rate of absorption, and the ultrasonically defined spatial resolution combine to reveal the spine, kidney, muscle, and other deeply seated anatomical features in the rat's abdominal cavity. This non-invasive and non-ionizing imaging modality achieved an imaging depth beyond 6 cm in the rat's tissue. Cancer diagnosis based on information about tissue properties from microwave band TAT can potentially be more accurate than has previously been achievable.

  3. Quantum state tomography of orbital angular momentum photonics qubits via a projection-based technique

    CERN Document Server

    Nicolas, Adrien; Giacobino, Elisabeth; Maxein, Dominik; Laurat, Julien

    2014-01-01

    While measuring the orbital angular momentum state of bright light beams can be performed using imaging techniques, a full characterization at the single-photon level is challenging. For applications to quantum optics and quantum information science, such characterization is an essential capability. Here, we present a setup to perform the quantum state tomography of photonic qubits encoded in this degree of freedom. The method is based on a projective technique using spatial mode projection via fork holograms and single-mode fibers inserted into an interferometer. The alignment and calibration of the device is detailed as well as the measurement sequence to reconstruct the associated density matrix. Possible extensions to higher-dimensional spaces are discussed.

  4. High-resolution mesoscopic fluorescence molecular tomography based on compressive sensing.

    Science.gov (United States)

    Yang, Fugang; Ozturk, Mehmet S; Zhao, Lingling; Cong, Wenxiang; Wang, Ge; Intes, Xavier

    2015-01-01

    Mesoscopic fluorescence molecular tomography (MFMT) is new imaging modality aiming at 3-D imaging of molecular probes in a few millimeter thick biological samples with high-spatial resolution. In this paper, we develop a compressive sensing-based reconstruction method with l1-norm regularization for MFMT with the goal of improving spatial resolution and stability of the optical inverse problem. Three-dimensional numerical simulations of anatomically accurate microvasculature and real data obtained from phantom experiments are employed to evaluate the merits of the proposed method. Experimental results show that the proposed method can achieve 80 μm spatial resolution for a biological sample of 3 mm thickness and more accurate quantifications of concentrations and locations for the fluorophore distribution than those of the conventional methods.

  5. A reconstruction algorithm for electrical impedance tomography based on sparsity regularization

    KAUST Repository

    Jin, Bangti

    2011-08-24

    This paper develops a novel sparse reconstruction algorithm for the electrical impedance tomography problem of determining a conductivity parameter from boundary measurements. The sparsity of the \\'inhomogeneity\\' with respect to a certain basis is a priori assumed. The proposed approach is motivated by a Tikhonov functional incorporating a sparsity-promoting ℓ 1-penalty term, and it allows us to obtain quantitative results when the assumption is valid. A novel iterative algorithm of soft shrinkage type was proposed. Numerical results for several two-dimensional problems with both single and multiple convex and nonconvex inclusions were presented to illustrate the features of the proposed algorithm and were compared with one conventional approach based on smoothness regularization. © 2011 John Wiley & Sons, Ltd.

  6. A Near-Infrared Optical Tomography System Based on Photomultiplier Tube

    Directory of Open Access Journals (Sweden)

    Huacheng Feng

    2007-01-01

    Full Text Available Diffuse optical tomography (DOT is a rapidly growing discipline in recent years. It plays an important role in many fields, such as detecting breast cancer and monitoring the cerebra oxygenation. In this paper, a relatively simple, inexpensive, and conveniently used DOT system is presented in detail, in which only one photomultiplier tube is employed as the detector and an optical multiplexer is used to alter the detector channels. The 32-channel imager is consisted of 16-launch fibers and 16-detector fibers bundles, which works in the near-infrared (NIR spectral range under continuous-wave (CW model. The entire imaging system can work highly automatically and harmoniously. Experiments based on the proposed imaging system were performed, and the desired results can be obtained. The experimental results suggested that the proposed imaging instrumentation is effective.

  7. Compact MEMS-based Adaptive Optics Optical Coherence Tomography for Clinical Use

    Energy Technology Data Exchange (ETDEWEB)

    Chen, D; Olivier, S; Jones, S; Zawadzki, R; Evans, J; Choi, S; Werner, J

    2008-02-04

    We describe a compact MEMS-based adaptive optics (AO) optical coherence tomography system with improved AO performance and ease of clinical use. A typical AO system consists of a Shack-Hartmann wavefront sensor and a deformable mirror that measures and corrects the ocular and system aberrations. Because of the limitation on the current deformable mirror technologies, the amount of real-time ocular-aberration compensation is restricted and small in the previous AO-OCT instruments. In this instrument, we proposed to add an optical apparatus to correct the spectacle aberrations of the patients such as myopia, hyperopia and astigmatism. This eliminated the tedious process of the trial lenses in clinical imaging. Different amount of spectacle aberration compensation was achieved by motorized stages and automated with the AO computer for ease of clinical use. In addition, the compact AO-OCT was optimized to have minimum system aberrations to reduce AO registration errors and improve AO performance.

  8. Fourier transform based iterative method for x-ray differential phase-contrast computed tomography

    CERN Document Server

    Cong, Wenxiang; Wang, Ge

    2011-01-01

    Biological soft tissues encountered in clinical and pre-clinical imaging mainly consist of light element atoms, and their composition is nearly uniform with little density variation. Thus, x-ray attenuation imaging suffers from low image contrast resolution. By contrast, x-ray phase shift of soft tissues is about a thousand times greater than x-ray absorption over the diagnostic energy range, thereby a significantly higher sensitivity can be achieved in terms of phase shift. In this paper, we propose a novel Fourier transform based iterative method to perform x-ray tomographic imaging of the refractive index directly from differential phase shift data. This approach offers distinct advantages in cases of incomplete and noisy data than analytic reconstruction, and especially suitable for phase-contrast interior tomography by incorporating prior knowledge in a region of interest (ROI). Biological experiments demonstrate the merits of the proposed approach.

  9. A projection-based approach to diffraction tomography on curved boundaries

    Science.gov (United States)

    Clement, Gregory T.

    2014-12-01

    An approach to diffraction tomography is investigated for two-dimensional image reconstruction of objects surrounded by an arbitrarily-shaped curve of sources and receivers. Based on the integral theorem of Helmholtz and Kirchhoff, the approach relies upon a valid choice of the Green’s functions for selected conditions along the (possibly-irregular) boundary. This allows field projections from the receivers to an arbitrary external location. When performed over all source locations, it will be shown that the field caused by a hypothetical source at this external location is also known along the boundary. This field can then be projected to new external points that may serve as a virtual receiver. Under such a reformation, data may be put in a form suitable for image construction by synthetic aperture methods. Foundations of the approach are shown, followed by a mapping technique optimized for the approach. Examples formed from synthetic data are provided.

  10. Fiber-Based Polarization Diversity Detection for Polarization-Sensitive Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Hamid Pahlevaninezhad

    2014-09-01

    Full Text Available We present a new fiber-based polarization diversity detection (PDD scheme for polarization sensitive optical coherence tomography (PSOCT. This implementation uses a new custom miniaturized polarization-maintaining fiber coupler with single mode (SM fiber inputs and polarization maintaining (PM fiber outputs. The SM fiber inputs obviate matching the optical lengths of the two orthogonal OCT polarization channels prior to interference while the PM fiber outputs ensure defined orthogonal axes after interference. Advantages of this detection scheme over those with bulk optics PDD include lower cost, easier miniaturization, and more relaxed alignment and handling issues. We incorporate this PDD scheme into a galvanometer-scanned OCT system to demonstrate system calibration and PSOCT imaging of an achromatic quarter-wave plate, fingernail in vivo, and chicken breast, salmon, cow leg, and basa fish muscle samples ex vivo.

  11. A novel luciferase fusion protein for highly sensitive optical imaging: from single-cell analysis to in vivo whole-body bioluminescence imaging.

    Science.gov (United States)

    Mezzanotte, Laura; Blankevoort, Vicky; Löwik, Clemens W G M; Kaijzel, Eric L

    2014-09-01

    Fluorescence and bioluminescence imaging have different advantages and disadvantages depending on the application. Bioluminescence imaging is now the most sensitive optical technique for tracking cells, promoter activity studies, or for longitudinal in vivo preclinical studies. Far-red and near-infrared fluorescence imaging have the advantage of being suitable for both ex vivo and in vivo analysis and have translational potential, thanks to the availability of very sensitive imaging instrumentation. Here, we report the development and validation of a new luciferase fusion reporter generated by the fusion of the firefly luciferase Luc2 to the far-red fluorescent protein TurboFP635 by a 14-amino acid linker peptide. Expression of the fusion protein, named TurboLuc, was analyzed in human embryonic kidney cells, (HEK)-293 cells, via Western blot analysis, fluorescence microscopy, and in vivo optical imaging. The created fusion protein maintained the characteristics of the original bioluminescent and fluorescent protein and showed no toxicity when expressed in living cells. To assess the sensitivity of the reporter for in vivo imaging, transfected cells were subcutaneously injected in animals. Detection limits of cells were 5 × 10(3) and 5 × 10(4) cells for bioluminescent and fluorescent imaging, respectively. In addition, hydrodynamics-based in vivo gene delivery using a minicircle vector expressing TurboLuc allowed for the analysis of luminescent signals over time in deep tissue. Bioluminescence could be monitored for over 30 days in the liver of animals. In conclusion, TurboLuc combines the advantages of both bioluminescence and fluorescence and allows for highly sensitive optical imaging ranging from single-cell analysis to in vivo whole-body bioluminescence imaging.

  12. A computer tomography-based spatial normalization for the analysis of [{sup 18}F]fluorodeoxyglucose position emission tomography of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hanna; Choi, Jae Yong; Ryu, Young Hoon; Lyoo, Chul Hyoung [Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Kim, Jin Su [Molecular Imaging Research Center, Korea Institute Radiological and Medical Science, Seoul(Korea, Republic of)

    2014-12-15

    We developed a new computed tomography (CT)-based spatial normalization method and CT template to demonstrate its usefulness in spatial normalization of positron emission tomography (PET) images with [{sup 18}F] fluorodeoxyglucose (FDG) PET studies in healthy controls. Seventy healthy controls underwent brain CT scan (120 KeV, 180 mAs, and 3 mm of thickness) and [{sup 18}F] FDG PET scans using a PET/CT scanner. T1-weighted magnetic resonance (MR) images were acquired for all subjects. By averaging skull-stripped and spatially-normalized MR and CT images, we created skull-stripped MR and CT templates for spatial normalization. The skull-stripped MR and CT images were spatially normalized to each structural template. PET images were spatially normalized by applying spatial transformation parameters to normalize skull-stripped MR and CT images. A conventional perfusion PET template was used for PET-based spatial normalization. Regional standardized uptake values (SUV) measured by overlaying the template volume of interest (VOI) were compared to those measured with FreeSurfer-generated VOI (FSVOI). All three spatial normalization methods underestimated regional SUV values by 0.3-20% compared to those measured with FSVOI. The CT-based method showed slightly greater underestimation bias. Regional SUV values derived from all three spatial normalization methods were correlated significantly (p < 0.0001) with those measured with FSVOI. CT-based spatial normalization may be an alternative method for structure-based spatial normalization of [18F] FDG PET when MR imaging is unavailable. Therefore, it is useful for PET/CT studies with various radiotracers whose uptake is expected to be limited to specific brain regions or highly variable within study population.

  13. Spectrally encoded common-path fiber-optic-based parallel optical coherence tomography.

    Science.gov (United States)

    Lee, Kye-Sung; Hur, Hwan; Sung, Ha-Young; Kim, I Jong; Kim, Geon-Hee

    2016-09-15

    We demonstrate a fiber-optic-based parallel optical coherence tomography (OCT) using spectrally encoded extended illumination with a common-path handheld probe, where the flexibility and robustness of the system are significantly improved, which is critical in the clinical environment. To the best of our knowledge, we present the first parallel OCT based on fiber optics including a fiber coupler with a sensitivity of 94 dB, which is comparable to that of point-scanning OCT. We also investigated the effect of the phase stability of the fiber-based interferometry on the parallel OCT system by comparing the common-path OCT with two-arm OCT. Using the homemade common-path handheld probe based on a Mirau interferometer, the phase stability was 32 times better than that of the two-arm OCT. The axial resolution of the common-path OCT was measured as 5.1±0.3  μm. To demonstrate the in vivo imaging performance of the fiber-optic-based parallel OCT, human skin was imaged. PMID:27628367

  14. Spectrally encoded common-path fiber-optic-based parallel optical coherence tomography.

    Science.gov (United States)

    Lee, Kye-Sung; Hur, Hwan; Sung, Ha-Young; Kim, I Jong; Kim, Geon-Hee

    2016-09-15

    We demonstrate a fiber-optic-based parallel optical coherence tomography (OCT) using spectrally encoded extended illumination with a common-path handheld probe, where the flexibility and robustness of the system are significantly improved, which is critical in the clinical environment. To the best of our knowledge, we present the first parallel OCT based on fiber optics including a fiber coupler with a sensitivity of 94 dB, which is comparable to that of point-scanning OCT. We also investigated the effect of the phase stability of the fiber-based interferometry on the parallel OCT system by comparing the common-path OCT with two-arm OCT. Using the homemade common-path handheld probe based on a Mirau interferometer, the phase stability was 32 times better than that of the two-arm OCT. The axial resolution of the common-path OCT was measured as 5.1±0.3  μm. To demonstrate the in vivo imaging performance of the fiber-optic-based parallel OCT, human skin was imaged.

  15. Comparing the Gibraltar and Calabrian subduction zones (central western Mediterranean) based on seismic tomography

    Science.gov (United States)

    Argnani, Andrea; Battista Cimini, Giovanni; Frugoni, Francesco; Monna, Stephen; Montuori, Caterina

    2016-04-01

    The Central Western Mediterranean (CWM) was shaped by a complex tectonic and geodynamic evolution. Deep seismicity and tomographic studies point to the existence, under the Alboran and Tyrrhenian Seas, of lithospheric slabs extending down to the bottom of the mantle transition zone, at 660 km depth. Two narrow arcs correspond to the two slabs, the Gibraltar and Calabrian Arcs (e.g., Monna et al., 2013; Montuori et al., 2007). Similarities in the tectonic and mantle structure of the two areas have been explained by a common subduction and roll-back mechanism for the opening of the CWM, in which the two arcs are symmetrical end products. In spite of this unifying model, a wide amount of literature from different disciplines shows that many aspects of the two areas are still controversial. We present a new 3-D tomographic model at mantle scale for the Calabrian Arc and compare it with a recently published 3-D tomographic model for the Gibraltar Arc by Monna et al (2013). The two models are based on non-linear inversion of teleseismic phase arrivals, and have scale and parametrization that allow for a direct comparison. Unlike previous studies the tomographic models here presented include Ocean Bottom Seismometer broadband data, which improved the resolution of the mantle structures in the marine areas surrounding the arcs. We focus on key features of the two models that constrain reconstructions of the geodynamic evolution of the CWM (e.g., Monna et al., 2015). At Tortonian time the opening of the Tyrrhenian basin was in its initial stage, and the Calabrian arc formed subsequently; on the contrary, the Gibraltar arc was almost completely defined. We hypothesize that the complexity of the continental margin approaching the subduction zone played a key role during the final stages of the arc formation. References Monna, S., G. B. Cimini, C. Montuori, L. Matias, W. H. Geissler, and P. Favali (2013), New insights from seismic tomography on the complex geodynamic evolution

  16. Special Section Guest Editorial:Selected Topics in Biophotonics: Photoacoustic Tomography and Fiber-Based Lasers and Supercontinuum Sources

    DEFF Research Database (Denmark)

    Andersson-Engels, Stefan; Andersen, Peter E.

    2016-01-01

    The present special section entitled “Selected Topics in Biophotonics: Photoacoustic Tomography and Fiber-Based Lasers and Supercontinuum Sources” comprises two invited papers and several contributed papers from the summer school Biophotonics ’15, as well as contributed papers within this general...

  17. aequorine bioluminescence response to calcium in vitro and in cerebral cortex

    OpenAIRE

    Tricoire, Ludovic

    2006-01-01

    During my PhD, I investigated in vitro the calcium-dependent bioluminescence of thephotoprotein aequorin and then used its bioluminescence to image neuronal activities in theneocortical network. This genetically encoded calcium sensor can be expressed in specific cell types and its bioluminescence is not toxic and exhibit a high signal/noise ratio.I first search for mutations modifying aequorin bioluminescence, using a randommutagenesis and in vitro evolution approach. I isolated mutants show...

  18. Modelling dinoflagellates as an approach to the seasonal forecasting of bioluminescence in the North Atlantic

    OpenAIRE

    Marcinko, Charlotte L.J.; Martin, Adrian P.; Allen, John T.

    2014-01-01

    Bioluminescence within ocean surface waters is of significant interest because it can enhance the study of subsurface movement and organisms. Little is known about how bioluminescence potential (BPOT) varies spatially and temporally in the open ocean. However, light emitted from dinoflagellates often dominates the stimulated bioluminescence field. As a first step towards forecasting surface ocean bioluminescence in the open ocean, a simple ecological model is developed which simulates seasona...

  19. Vegetable seed radiosensitivity and kinetic analysis of super-weak bioluminescence

    International Nuclear Information System (INIS)

    Bioluminescence of several vegetable seeds induced by γ-rays was studied. The results show that positive relation exists between seeds bioluminescence and irradiation dose, which fits with equation Y=Y0eKD. The higher the K value is, the more intense the bioluminescence induced by γ-rays is. Significant differences among K values were found with different varieties. The bioluminescence and exterior measurement value of seed radiosensitivity showed good consistency

  20. Bioluminescence in vivo imaging of autoimmune encephalomyelitis predicts disease

    Directory of Open Access Journals (Sweden)

    Steinman Lawrence

    2008-02-01

    Full Text Available Abstract Background Experimental autoimmune encephalomyelitis is a widely used animal model to understand not only multiple sclerosis but also basic principles of immunity. The disease is scored typically by observing signs of paralysis, which do not always correspond with pathological changes. Methods Experimental autoimmune encephalomyelitis was induced in transgenic mice expressing an injury responsive luciferase reporter in astrocytes (GFAP-luc. Bioluminescence in the brain and spinal cord was measured non-invasively in living mice. Mice were sacrificed at different time points to evaluate clinical and pathological changes. The correlation between bioluminescence and clinical and pathological EAE was statistically analyzed by Pearson correlation analysis. Results Bioluminescence from the brain and spinal cord correlates strongly with severity of clinical disease and a number of pathological changes in the brain in EAE. Bioluminescence at early time points also predicts severity of disease. Conclusion These results highlight the potential use of bioluminescence imaging to monitor neuroinflammation for rapid drug screening and immunological studies in EAE and suggest that similar approaches could be applied to other animal models of autoimmune and inflammatory disorders.

  1. Influence of antibiotic pressure on bacterial bioluminescence, with emphasis on Staphylococcus aureus

    NARCIS (Netherlands)

    Daghighi, Seyedmojtaba; Sjollema, Jelmer; Harapanahalli, Akshay; Dijkstra, Rene J. B.; van der Mei, Henny C.; Busscher, Henk J.

    2015-01-01

    Bioluminescence imaging is used for longitudinal evaluation of bacteria in live animals. Clear relations exist between bacterial numbers and their bioluminescence. However, bioluminescence images of Staphylococcus aureus Xen29, S. aureus Xen36 and Escherichia coli Xen14 grown on tryptone soy agar in

  2. Rapid detection (4 h) of methicillin-resistant Staphylococcus aureus by a bioluminescence method.

    OpenAIRE

    Park, C. H.; Hixon, D L; McLaughlin, C M; Cook, J F

    1988-01-01

    A 4-h bioluminescence method for methicillin susceptibility determination was compared with reference methods. Of the Staphylococcus aureus strains tested, 80 were methicillin resistant, 180 were methicillin susceptible, and 10 were borderline susceptible. There was 100% correlation between bioluminescence and reference methods for methicillin-susceptible and methicillin-resistant strains. All borderline-susceptible strains were identified as methicillin resistant by bioluminescence.

  3. Novel bioluminescent coelenterazine derivatives with imidazopyrazinone C-6 extended substitution for Renilla luciferase.

    Science.gov (United States)

    Jiang, Tianyu; Yang, Xiaofeng; Yang, Xingye; Yuan, Mingliang; Zhang, Tianchao; Zhang, Huateng; Li, Minyong

    2016-06-21

    Two series of novel coelenterazine analogues (alkynes and triazoles) with imidazopyrazinone C-6 extended substitution have been designed and synthesized successfully for the extension of bioluminescent substrates. After extensive evaluation, some compounds display excellent bioluminescence properties compared with DeepBlueC in cellulo, thus becoming potential molecules for bioluminescence techniques. PMID:27197767

  4. Optic axis determination by fibre-based polarization-sensitive swept-source optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lu Zenghai; Kasaragod, Deepa K; Matcher, Stephen J, E-mail: z.lu@sheffield.ac.uk, E-mail: s.j.matcher@sheffield.ac.uk [Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, North Campus, Broad Lane, Sheffield, S3 7HQ (United Kingdom)

    2011-02-21

    We describe a fibre-based variable-incidence angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3D optical axis of birefringent biological tissues. Single-plane VIA-PS-OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by the VIA method and compared with the nominal values. A quarter waveplate (QWP) and equine tendon were used as test targets to validate the fast-axis measurements using the system. Polar and azimuthal angles of cut equine tendon broadly agreed with the expected values within about 8% of the nominal values. A theoretical and experimental analysis of the effect of the sample arm fibre on determination of optical axis orientation using a proposed definition based on the orientation of the eigenpolarization ellipse experimentally confirms that this algorithm only works correctly for special settings of the sample arm fibre. A proposed algorithm based on the angle between Stokes vectors on the Poincare sphere is confirmed to work for all settings of the sample arm fibre. A calibration procedure is proposed to remove the sign ambiguity of the measured orientation and was confirmed experimentally by using the QWP.

  5. Feasibility of computed tomography based thermometry during interstitial laser heating in bovine liver

    International Nuclear Information System (INIS)

    To assess the feasibility of computed tomography (CT) based thermometry during interstitial laser heating in the bovine liver. Four freshly exercised cylindrical blocks of bovine tissue were heated using a continuous laser of Nd:YAG (wavelength: 1064 nm, active length: 30 mm, power: 10-30 W). All tissues were imaged at least once before and 7 times during laser heating using CT and temperatures were simultaneously measured with 5 calibrated thermal sensors. The dependency of the average CT numbers as a function of temperature was analysed with regression analysis and a CT thermal sensitivity was derived. During laser heating, the growing hypodense area was observed around the laser source and that area showed an increase as a function of time. The formation of hypodense area was caused by declining in CT numbers at increasing temperatures. The regression analysis showed an inverse linear dependency between temperature and average CT number with -0.65 ± 0.048 HU/ C (R2 = 0.75) for the range of 18-85 C in bovine liver. The non-invasive CT based thermometry during interstitial laser heating is feasible in the bovine liver. CT based thermometry could be further developed and may be of potential use during clinical LITT of the liver. (orig.)

  6. Electrical impedance tomography-based sensing skin for quantitative imaging of damage in concrete

    International Nuclear Information System (INIS)

    This paper outlines the development of a large-area sensing skin for damage detection in concrete structures. The developed sensing skin consists of a thin layer of electrically conductive copper paint that is applied to the surface of the concrete. Cracking of the concrete substrate results in the rupture of the sensing skin, decreasing its electrical conductivity locally. The decrease in conductivity is detected with electrical impedance tomography (EIT) imaging. In previous works, electrically based sensing skins have provided only qualitative information on the damage on the substrate surface. In this paper, we study whether quantitative imaging of the damage is possible. We utilize application-specific models and computational methods in the image reconstruction, including a total variation (TV) prior model for the damage and an approximate correction of the modeling errors caused by the inhomogeneity of the painted sensing skin. The developed damage detection method is tested experimentally by applying the sensing skin to polymeric substrates and a reinforced concrete beam under four-point bending. In all test cases, the EIT-based sensing skin provides quantitative information on cracks and/or other damages on the substrate surface: featuring a very low conductivity in the damage locations, and a reliable indication of the lengths and shapes of the cracks. The results strongly support the applicability of the painted EIT-based sensing skin for damage detection in reinforced concrete elements and other substrates. (paper)

  7. Optic axis determination by fibre-based polarization-sensitive swept-source optical coherence tomography

    Science.gov (United States)

    Lu, Zenghai; Kasaragod, Deepa K.; Matcher, Stephen J.

    2011-02-01

    We describe a fibre-based variable-incidence angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3D optical axis of birefringent biological tissues. Single-plane VIA-PS-OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by the VIA method and compared with the nominal values. A quarter waveplate (QWP) and equine tendon were used as test targets to validate the fast-axis measurements using the system. Polar and azimuthal angles of cut equine tendon broadly agreed with the expected values within about 8% of the nominal values. A theoretical and experimental analysis of the effect of the sample arm fibre on determination of optical axis orientation using a proposed definition based on the orientation of the eigenpolarization ellipse experimentally confirms that this algorithm only works correctly for special settings of the sample arm fibre. A proposed algorithm based on the angle between Stokes vectors on the Poincaré sphere is confirmed to work for all settings of the sample arm fibre. A calibration procedure is proposed to remove the sign ambiguity of the measured orientation and was confirmed experimentally by using the QWP.

  8. Optic axis determination by fiber-based polarization-sensitive swept-source optical coherence tomography

    Science.gov (United States)

    Lu, Zenghai; Kasaragod, Deepa K.; Matcher, Stephen J.

    2011-03-01

    We describe a fiber-based variable-incidence-angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3-D optical axis of birefringent biological tissues. Single-plane VIAPS- OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by VIA method and compared with the nominal values. A quarter waveplate (QWP) and equine tendon were used as test targets to validate the fast-axis measurements using the system. Polar and azimuthal angles of cut equine tendon broadly agreed with the expected values within about 8% of the nominal values. A theoretical and experimental analysis of the effect of the sample arm fiber on determination of optical axis orientation using a proposed definition based on the orientation of the eigenpolarization ellipse experimentally confirms that this algorithm only works correctly for special settings of the sample arm fiber. A proposed algorithm based on the angle between Stokes vectors on the Poincaré sphere is confirmed to work for all settings of the sample arm fiber. A calibration procedure is proposed to remove the sign ambiguity of the measured orientation and was confirmed experimentally by using the QWP.

  9. Evaluation of electrical capacitance tomography sensor based on the coupling of fluid field and electrostatic field

    Science.gov (United States)

    Ye, Jiamin; Wang, Haigang; Yang, Wuqiang

    2016-07-01

    Electrical capacitance tomography (ECT) is based on capacitance measurements from electrode pairs mounted outside of a pipe or vessel. The structure of ECT sensors is vital to image quality. In this paper, issues with the number of electrodes and the electrode covering ratio for complex liquid-solids flows in a rotating device are investigated based on a new coupling simulation model. The number of electrodes is increased from 4 to 32 while the electrode covering ratio is changed from 0.1 to 0.9. Using the coupling simulation method, real permittivity distributions and the corresponding capacitance data at 0, 0.5, 1, 2, 3, 5, and 8 s with a rotation speed of 96 rotations per minute (rpm) are collected. Linear back projection (LBP) and Landweber iteration algorithms are used for image reconstruction. The quality of reconstructed images is evaluated by correlation coefficient compared with the real permittivity distributions obtained from the coupling simulation. The sensitivity for each sensor is analyzed and compared with the correlation coefficient. The capacitance data with a range of signal-to-noise ratios (SNRs) of 45, 50, 55 and 60 dB are generated to evaluate the effect of data noise on the performance of ECT sensors. Furthermore, the SNRs of experimental data are analyzed for a stationary pipe with permittivity distribution. Based on the coupling simulation, 16-electrode ECT sensors are recommended to achieve good image quality.

  10. Feasibility of computed tomography based thermometry during interstitial laser heating in bovine liver

    Energy Technology Data Exchange (ETDEWEB)

    Pandeya, G.D. [University of Groningen, Department of Radiology, UMC Groningen, Hanzeplein 1, PO Box 30001, Groningen (Netherlands); Siemens AG, H IM CT PLM-E PA, Forchheim (Germany); Klaessens, J.H.G.M. [UMC Utrecht, Department of Medical Technology and Clinical Physics, Utrecht (Netherlands); Greuter, M.J.W.; Oudkerk, M. [University of Groningen, Department of Radiology, UMC Groningen, Hanzeplein 1, PO Box 30001, Groningen (Netherlands); Schmidt, B.; Flohr, T. [Siemens AG, H IM CT PLM-E PA, Forchheim (Germany); Hillegersberg, R. van [UMC Utrecht, Department of Surgical Oncology, Utrecht (Netherlands)

    2011-08-15

    To assess the feasibility of computed tomography (CT) based thermometry during interstitial laser heating in the bovine liver. Four freshly exercised cylindrical blocks of bovine tissue were heated using a continuous laser of Nd:YAG (wavelength: 1064 nm, active length: 30 mm, power: 10-30 W). All tissues were imaged at least once before and 7 times during laser heating using CT and temperatures were simultaneously measured with 5 calibrated thermal sensors. The dependency of the average CT numbers as a function of temperature was analysed with regression analysis and a CT thermal sensitivity was derived. During laser heating, the growing hypodense area was observed around the laser source and that area showed an increase as a function of time. The formation of hypodense area was caused by declining in CT numbers at increasing temperatures. The regression analysis showed an inverse linear dependency between temperature and average CT number with -0.65 {+-} 0.048 HU/ C (R{sup 2} = 0.75) for the range of 18-85 C in bovine liver. The non-invasive CT based thermometry during interstitial laser heating is feasible in the bovine liver. CT based thermometry could be further developed and may be of potential use during clinical LITT of the liver. (orig.)

  11. Diffuse fluorescence tomography based on the radiative transfer equation for small animal imaging

    Science.gov (United States)

    Wang, Yihan; Zhang, Limin; Zhao, Huijuan; Gao, Feng; Li, Jiao

    2014-02-01

    Diffuse florescence tomography (DFT) as a high-sensitivity optical molecular imaging tool, can be applied to in vivo visualize interior cellular and molecular events for small-animal disease model through quantitatively recovering biodistributions of specific molecular probes. In DFT, the radiative transfer equation (RTE) and its approximation, such as the diffuse equation (DE), have been used as the forward models. The RTE-based DFT methodology is more suitable for biological tissue having void-like regions and the near-source area as in the situations of small animal imaging. We present a RTE-based scheme for the steady state DFT, which combines the discrete solid angle method and the finite difference method to obtain numerical solutions of the 2D steady RTE, with the natural boundary condition and collimating light source model. The approach is validated using the forward data from the Monte Carlo simulation for its better performances in the spatial resolution and reconstruction fidelity compared to the DE-based scheme.

  12. Real-time Graphics Processing Unit Based Fourier Domain Optical Coherence Tomography and Surgical Applications

    Science.gov (United States)

    Zhang, Kang

    2011-12-01

    In this dissertation, real-time Fourier domain optical coherence tomography (FD-OCT) capable of multi-dimensional micrometer-resolution imaging targeted specifically for microsurgical intervention applications was developed and studied. As a part of this work several ultra-high speed real-time FD-OCT imaging and sensing systems were proposed and developed. A real-time 4D (3D+time) OCT system platform using the graphics processing unit (GPU) to accelerate OCT signal processing, the imaging reconstruction, visualization, and volume rendering was developed. Several GPU based algorithms such as non-uniform fast Fourier transform (NUFFT), numerical dispersion compensation, and multi-GPU implementation were developed to improve the impulse response, SNR roll-off and stability of the system. Full-range complex-conjugate-free FD-OCT was also implemented on the GPU architecture to achieve doubled image range and improved SNR. These technologies overcome the imaging reconstruction and visualization bottlenecks widely exist in current ultra-high speed FD-OCT systems and open the way to interventional OCT imaging for applications in guided microsurgery. A hand-held common-path optical coherence tomography (CP-OCT) distance-sensor based microsurgical tool was developed and validated. Through real-time signal processing, edge detection and feed-back control, the tool was shown to be capable of track target surface and compensate motion. The micro-incision test using a phantom was performed using a CP-OCT-sensor integrated hand-held tool, which showed an incision error less than +/-5 microns, comparing to >100 microns error by free-hand incision. The CP-OCT distance sensor has also been utilized to enhance the accuracy and safety of optical nerve stimulation. Finally, several experiments were conducted to validate the system for surgical applications. One of them involved 4D OCT guided micro-manipulation using a phantom. Multiple volume renderings of one 3D data set were

  13. Positron Emission Tomography/Computed Tomography Imaging of Residual Skull Base Chordoma Before Radiotherapy Using Fluoromisonidazole and Fluorodeoxyglucose: Potential Consequences for Dose Painting

    Energy Technology Data Exchange (ETDEWEB)

    Mammar, Hamid, E-mail: hamid.mammar@unice.fr [Radiation Oncology Department, Antoine Lacassagne Center, Nice (France); CNRS-UMR 6543, Institute of Developmental Biology and Cancer, University of Nice Sophia Antipolis, Nice (France); Kerrou, Khaldoun; Nataf, Valerie [Department of Nuclear Medicine and Radiopharmacy, Tenon Hospital, and University Pierre et Marie Curie, Paris (France); Pontvert, Dominique [Proton Therapy Center of Orsay, Curie Institute, Paris (France); Clemenceau, Stephane [Department of Neurosurgery, Pitie-Salpetriere Hospital, Paris (France); Lot, Guillaume [Department of Neurosurgery, Adolph De Rothschild Foundation, Paris (France); George, Bernard [Department of Neurosurgery, Lariboisiere Hospital, Paris (France); Polivka, Marc [Department of Pathology, Lariboisiere Hospital, Paris (France); Mokhtari, Karima [Department of Pathology, Pitie-Salpetriere Hospital, Paris (France); Ferrand, Regis; Feuvret, Loiec; Habrand, Jean-louis [Proton Therapy Center of Orsay, Curie Institute, Paris (France); Pouyssegur, Jacques; Mazure, Nathalie [CNRS-UMR 6543, Institute of Developmental Biology and Cancer, University of Nice Sophia Antipolis, Nice (France); Talbot, Jean-Noeel [Department of Nuclear Medicine and Radiopharmacy, Tenon Hospital, and University Pierre et Marie Curie, Paris (France)

    2012-11-01

    Purpose: To detect the presence of hypoxic tissue, which is known to increase the radioresistant phenotype, by its uptake of fluoromisonidazole (18F) (FMISO) using hybrid positron emission tomography/computed tomography (PET/CT) imaging, and to compare it with the glucose-avid tumor tissue imaged with fluorodeoxyglucose (18F) (FDG), in residual postsurgical skull base chordoma scheduled for radiotherapy. Patients and Methods: Seven patients with incompletely resected skull base chordomas were planned for high-dose radiotherapy (dose {>=}70 Gy). All 7 patients underwent FDG and FMISO PET/CT. Images were analyzed qualitatively by visual examination and semiquantitatively by computing the ratio of the maximal standardized uptake value (SUVmax) of the tumor and cerebellum (T/C R), with delineation of lesions on conventional imaging. Results: Of the eight lesion sites imaged with FDG PET/CT, only one was visible, whereas seven of nine lesions were visible on FMISO PET/CT. The median SUVmax in the tumor area was 2.8 g/mL (minimum 2.1; maximum 3.5) for FDG and 0.83 g/mL (minimum 0.3; maximum 1.2) for FMISO. The T/C R values ranged between 0.30 and 0.63 for FDG (median, 0.41) and between 0.75 and 2.20 for FMISO (median,1.59). FMISO T/C R >1 in six lesions suggested the presence of hypoxic tissue. There was no correlation between FMISO and FDG uptake in individual chordomas (r = 0.18, p = 0.7). Conclusion: FMISO PET/CT enables imaging of the hypoxic component in residual chordomas. In the future, it could help to better define boosted volumes for irradiation and to overcome the radioresistance of these lesions. No relationship was founded between hypoxia and glucose metabolism in these tumors after initial surgery.

  14. The Expanding Toolbox of In Vivo Bioluminescent Imaging

    Science.gov (United States)

    Xu, Tingting; Close, Dan; Handagama, Winode; Marr, Enolia; Sayler, Gary; Ripp, Steven

    2016-01-01

    In vivo bioluminescent imaging (BLI) permits the visualization of engineered bioluminescence from living cells and tissues to provide a unique perspective toward the understanding of biological processes as they occur within the framework of an authentic in vivo environment. The toolbox of in vivo BLI includes an inventory of luciferase compounds capable of generating bioluminescent light signals along with sophisticated and powerful instrumentation designed to detect and quantify these light signals non-invasively as they emit from the living subject. The information acquired reveals the dynamics of a wide range of biological functions that play key roles in the physiological and pathological control of disease and its therapeutic management. This mini review provides an overview of the tools and applications central to the evolution of in vivo BLI as a core technology in the preclinical imaging disciplines. PMID:27446798

  15. The Expanding Toolbox of In Vivo Bioluminescent Imaging.

    Science.gov (United States)

    Xu, Tingting; Close, Dan; Handagama, Winode; Marr, Enolia; Sayler, Gary; Ripp, Steven

    2016-01-01

    In vivo bioluminescent imaging (BLI) permits the visualization of engineered bioluminescence from living cells and tissues to provide a unique perspective toward the understanding of biological processes as they occur within the framework of an authentic in vivo environment. The toolbox of in vivo BLI includes an inventory of luciferase compounds capable of generating bioluminescent light signals along with sophisticated and powerful instrumentation designed to detect and quantify these light signals non-invasively as they emit from the living subject. The information acquired reveals the dynamics of a wide range of biological functions that play key roles in the physiological and pathological control of disease and its therapeutic management. This mini review provides an overview of the tools and applications central to the evolution of in vivo BLI as a core technology in the preclinical imaging disciplines. PMID:27446798

  16. Efficient non-negative constrained model-based inversion in optoacoustic tomography

    Science.gov (United States)

    Ding, Lu; Luís Deán-Ben, X.; Lutzweiler, Christian; Razansky, Daniel; Ntziachristos, Vasilis

    2015-09-01

    The inversion accuracy in optoacoustic tomography depends on a number of parameters, including the number of detectors employed, discrete sampling issues or imperfectness of the forward model. These parameters result in ambiguities on the reconstructed image. A common ambiguity is the appearance of negative values, which have no physical meaning since optical absorption can only be higher or equal than zero. We investigate herein algorithms that impose non-negative constraints in model-based optoacoustic inversion. Several state-of-the-art non-negative constrained algorithms are analyzed. Furthermore, an algorithm based on the conjugate gradient method is introduced in this work. We are particularly interested in investigating whether positive restrictions lead to accurate solutions or drive the appearance of errors and artifacts. It is shown that the computational performance of non-negative constrained inversion is higher for the introduced algorithm than for the other algorithms, while yielding equivalent results. The experimental performance of this inversion procedure is then tested in phantoms and small animals, showing an improvement in image quality and quantitativeness with respect to the unconstrained approach. The study performed validates the use of non-negative constraints for improving image accuracy compared to unconstrained methods, while maintaining computational efficiency.

  17. Iterative reconstruction using a Monte Carlo based system transfer matrix for dedicated breast positron emission tomography.

    Science.gov (United States)

    Saha, Krishnendu; Straus, Kenneth J; Chen, Yu; Glick, Stephen J

    2014-08-28

    To maximize sensitivity, it is desirable that ring Positron Emission Tomography (PET) systems dedicated for imaging the breast have a small bore. Unfortunately, due to parallax error this causes substantial degradation in spatial resolution for objects near the periphery of the breast. In this work, a framework for computing and incorporating an accurate system matrix into iterative reconstruction is presented in an effort to reduce spatial resolution degradation towards the periphery of the breast. The GATE Monte Carlo Simulation software was utilized to accurately model the system matrix for a breast PET system. A strategy for increasing the count statistics in the system matrix computation and for reducing the system element storage space was used by calculating only a subset of matrix elements and then estimating the rest of the elements by using the geometric symmetry of the cylindrical scanner. To implement this strategy, polar voxel basis functions were used to represent the object, resulting in a block-circulant system matrix. Simulation studies using a breast PET scanner model with ring geometry demonstrated improved contrast at 45% reduced noise level and 1.5 to 3 times resolution performance improvement when compared to MLEM reconstruction using a simple line-integral model. The GATE based system matrix reconstruction technique promises to improve resolution and noise performance and reduce image distortion at FOV periphery compared to line-integral based system matrix reconstruction.

  18. A Micromegas-based telescope for muon tomography: The WatTo experiment

    Science.gov (United States)

    Bouteille, S.; Attié, D.; Baron, P.; Calvet, D.; Magnier, P.; Mandjavidze, I.; Procureur, S.; Riallot, M.; Winkler, M.

    2016-10-01

    This paper reports about the first Micromegas-based telescope built for applications in muon tomography. The telescope consists of four, 50×50 cm2 resistive multiplexed Micromegas with a 2D layout and a self-triggering electronics based on the Dream chip. Thanks to the multiplexing, the four detectors were readout with a single Front-End Unit. The high voltages were provided by a dedicated card using low consumption CAEN miniaturized modules. A nano-PC (Hummingboard) ensured the HV control and monitoring coupled with a temperature feedback as well as the data acquisition and storage. The overall consumption of the instrument yielded 30 W only, i.e. the equivalent of a standard bulb. The telescope was operated outside during 3.5 months to image the water tower of the CEA-Saclay research center, including a 1.5-month campaign with solar panels. The development of autonomous, low consumption muon telescopes with unprecedented accuracy opens new applications in imaging as well as in the field of muon metrology.

  19. Application of a computed tomography based cystic fibrosis scoring system to chest tomosynthesis

    Science.gov (United States)

    Söderman, Christina; Johnsson, Åse; Vikgren, Jenny; Rystedt, Hans; Ivarsson, Jonas; Rossi Norrlund, Rauni; Nyberg Andersson, Lena; Bâth, Magnus

    2013-03-01

    In the monitoring of progression of lung disease in patients with cystic fibrosis (CF), recurrent computed tomography (CT) examinations are often used. The relatively new imaging technique chest tomosynthesis (CTS) may be an interesting alternative in the follow-up of these patients due to its visualization of the chest in slices at radiation doses and costs significantly lower than is the case with CT. A first step towards introducing CTS imaging in the diagnostics of CF patients is to establish a scoring system appropriate for evaluating the severity of CF pulmonary disease based on findings in CTS images. Previously, several such CF scoring systems based on CT imaging have been published. The purpose of the present study was to develop a CF scoring system for CTS, by starting from an existing scoring system dedicated for CT images and making modifications regarded necessary to make it appropriate for use with CTS images. In order to determine any necessary changes, three thoracic radiologists independently used a scoring system dedicated for CT on both CT and CTS images from CF patients. The results of the scoring were jointly evaluated by all the observers, which lead to suggestions for changes to the scoring system. Suggested modifications include excluding the scoring of air trapping and doing the scoring of the findings in quadrants of the image instead of in each lung lobe.

  20. Damage detection tomography based on guided waves in composite structures using a distributed sensor network

    Science.gov (United States)

    Memmolo, Vittorio; Maio, Leandro; Boffa, Natalino Daniele; Monaco, Ernesto; Ricci, Fabrizio

    2016-01-01

    Structural health monitoring (SHM) based on guided waves allows assessing the health of a structure due to the sensitivity to the occurrence of delamination. However, wave propagation presents several complexities for effective damage identification in composite structures. An efficient implementation of a guided wave-based SHM system requires an accurate analysis of collected data to obtain a useful detection. This paper is concerned with the identification of small emerging delaminations in composite structural components using a sparse array of surface ultrasonic transducers. An ultrasonic-guided wave tomography technique focused on impact damage detection in composite plate-like structures is presented. A statistical damage index approach is adopted to interpret the recorded signals, and a subsequent graphic interpolation is implemented to reconstruct the damage appearance. Experimental tests carried out on a typical composite structure demonstrated the effectiveness of the developed technique with the aim to investigate the presence and location of damage using simple imaging reports and a limited number of measurements. A traditional ultrasonic inspection (C-scan) is used to assess the methodology.

  1. Development and reproducibility of a computed tomography-based measurement of renal sinus fat

    Directory of Open Access Journals (Sweden)

    Porter Stacy A

    2011-10-01

    Full Text Available Abstract Background Renal sinus fat may mediate obesity-related vascular disease, although this fat depot has not been assessed in a community-based sample. We sought to develop a protocol to quantify renal sinus fat accumulation using multi-detector computed tomography (MDCT. Methods Protocol development was performed in participants in the Framingham Offspring cohort who underwent MDCT. Volumetric renal sinus fat was measured separately within the right and left kidneys, and renal sinus fat area within a single MDCT scan slice was measured in the right kidney. Due to the high correlation of volumetric and single-slice renal sinus fat in the right kidney (Pearson correlation [r] = 0.85, p Results Single-slice measurements were obtained in 92 participants (mean age 60 years, 49% women, median renal sinus fat 0.43 cm2. Intra- and inter-reader intra-class correlation coefficients were 0.93 and 0.86, respectively. Single-slice renal sinus fat was correlated with body mass index (r = 0.35, p = 0.0006, waist circumference (r = 0.31, p = 0.003, and abdominal visceral fat (r = 0.48, p Conclusions Measuring renal sinus fat is feasible and reproducible using MDCT scans in a community-based sample.

  2. Bioluminescent bacteria: lux genes as environmental biosensors Bactérias bioluminescentes: os genes lux como biosensores ambientais

    OpenAIRE

    Vânia da Silva Nunes-Halldorson; Norma Letícia Duran

    2003-01-01

    Bioluminescent bacteria are widespread in natural environments. Over the years, many researchers have been studying the physiology, biochemistry and genetic control of bacterial bioluminescence. These discoveries have revolutionized the area of Environmental Microbiology through the use of luminescent genes as biosensors for environmental studies. This paper will review the chronology of scientific discoveries on bacterial bioluminescence and the current applications of bioluminescence in env...

  3. Concept of a novel fast neutron imaging detector based on THGEM for fan-beam tomography applications

    OpenAIRE

    Cortesi, M.; Zboray, R.; Adams, R.; Dangendorf, V.; Prasser, H.-M.

    2012-01-01

    The conceptual design and operational principle of a novel high-efficiency, fast neutron imaging detector based on THGEM, intended for future fan-beam transmission tomography applications, is described. We report on a feasibility study based on theoretical modeling and computer simulations of a possible detector configuration prototype. In particular we discuss results regarding the optimization of detector geometry, estimation of its general performance, and expected imaging quality: it has ...

  4. Atlas-based high-density diffuse optical tomography for imaging the whole human cortex

    Science.gov (United States)

    Wu, Xue; Eggebrecht, Adam T.; Ferradal, Silvina L.; Culver, Joseph P.; Dehghani, Hamid

    2015-03-01

    Diffuse optical tomography (DOT) for brain imaging has the potential to be an alternative human brain mapping technique when MRI imaging is not applicable. It recovers tissue chromophore concentrations of brain tissue through measures of light transmission to monitor for example the resting-state brain dynamics. This imaging technique relies on simulation of the light propagation which can be generated based on a subject-specific model. There has been some study on using rigid atlas models as alternatives for model based DOT when subject-specific anatomical data is not available; but there is still a lack of detailed analysis between geometrical accuracy and internal light propagation in tissue for atlas-based DOT. This work is focused on High-Density DOT (HD-DOT) of the whole cortex based on atlas models from 11 different rigid registration algorithms across 24 subjects, and the results are evaluated in 19 areas of the human head. The correlation between geometrical surface error and internal light propagation errors is strong in most area but varies in different regions from R2 = 0.74 in the region around top of the head to R2 = 0.98 in the region around the temples. In the 11 registration methods, basic-4-landmark registration with 4.2mm average surface error and 50% average internal light propagation errors is shown to be the least accurate registration method whereas full-head landmark with non-iterative point to point with 1.7mm average surface error and 32% average internal light propagation error is shown to be the most accurate registration method for atlas-based DOT.

  5. MEMS-based handheld fourier domain Doppler optical coherence tomography for intraoperative microvascular anastomosis imaging.

    Directory of Open Access Journals (Sweden)

    Yong Huang

    Full Text Available To demonstrate the feasibility of a miniature handheld optical coherence tomography (OCT imager for real time intraoperative vascular patency evaluation in the setting of super-microsurgical vessel anastomosis.A novel handheld imager Fourier domain Doppler optical coherence tomography based on a 1.3-µm central wavelength swept source for extravascular imaging was developed. The imager was minimized through the adoption of a 2.4-mm diameter microelectromechanical systems (MEMS scanning mirror, additionally a 12.7-mm diameter lens system was designed and combined with the MEMS mirror to achieve a small form factor that optimize functionality as a handheld extravascular OCT imager. To evaluate in-vivo applicability, super-microsurgical vessel anastomosis was performed in a mouse femoral vessel cut and repair model employing conventional interrupted suture technique as well as a novel non-suture cuff technique. Vascular anastomosis patency after clinically successful repair was evaluated using the novel handheld OCT imager.With an adjustable lateral image field of view up to 1.5 mm by 1.5 mm, high-resolution simultaneous structural and flow imaging of the blood vessels were successfully acquired for BALB/C mouse after orthotopic hind limb transplantation using a non-suture cuff technique and BALB/C mouse after femoral artery anastomosis using a suture technique. We experimentally quantify the axial and lateral resolution of the OCT to be 12.6 µm in air and 17.5 µm respectively. The OCT has a sensitivity of 84 dB and sensitivity roll-off of 5.7 dB/mm over an imaging range of 5 mm. Imaging with a frame rate of 36 Hz for an image size of 1000(lateral×512(axial pixels using a 50,000 A-lines per second swept source was achieved. Quantitative vessel lumen patency, lumen narrowing and thrombosis analysis were performed based on acquired structure and Doppler images.A miniature handheld OCT imager that can be used for intraoperative evaluation of

  6. Space application research of EMCCDs for bioluminescence imaging

    Science.gov (United States)

    Zhang, Tao

    The detection of bioluminescense is widely used on the ground, while the detection of bioluminescence in space is still at the stage of detecting bright bioluminescense. With the rapid development of research in Space Life Sciences, it will be necessary to develop a detection technology to detect weak bioluminescense. Compared to other low-light detection techniques for ground, there are more advantages of EMCCDs for space application. Build a space bioluminescence imaging detection system, analysis the feasibility and capability of its will be significant. Co-Author:Xie Zongbao,Zheng Weibo

  7. Effect of irradiation on bioluminescence spectrum of microbial ATP

    International Nuclear Information System (INIS)

    The effect of irradiation on bioluminescence spectrum of dehydrated cabbage microbial ATP was studied. The results showed that the spectral bandwidth of ATP standard was from 490 to 640 nm and the peak wavelength was at 563 nm. The spectral bandwidths of irradiated dehydrated cabbage microbial ATP and CK did not change. Peak wavelengths of dehydrated cabbage irradiated at different dosages were not significantly different from that of CK. The peaks of bioluminescence spectrum of irradiated samples were higher than that of CK, which may be because of the increasing concentration of ATP, and this effect would be kept for quite a long time after irradiation. (authors)

  8. Model-based image reconstruction in X-ray computed tomography

    NARCIS (Netherlands)

    Zbijewski, Wojciech Bartosz

    2006-01-01

    The thesis investigates the applications of iterative, statistical reconstruction (SR) algorithms in X-ray Computed Tomography. Emphasis is put on various aspects of system modeling in statistical reconstruction. Fundamental issues such as effects of object discretization and algorithm initializatio

  9. High performance graphics processor based computed tomography reconstruction algorithms for nuclear and other large scale applications.

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, Edward Steven,

    2013-09-01

    The goal of this work is to develop a fast computed tomography (CT) reconstruction algorithm based on graphics processing units (GPU) that achieves significant improvement over traditional central processing unit (CPU) based implementations. The main challenge in developing a CT algorithm that is capable of handling very large datasets is parallelizing the algorithm in such a way that data transfer does not hinder performance of the reconstruction algorithm. General Purpose Graphics Processing (GPGPU) is a new technology that the Science and Technology (S&T) community is starting to adopt in many fields where CPU-based computing is the norm. GPGPU programming requires a new approach to algorithm development that utilizes massively multi-threaded environments. Multi-threaded algorithms in general are difficult to optimize since performance bottlenecks occur that are non-existent in single-threaded algorithms such as memory latencies. If an efficient GPU-based CT reconstruction algorithm can be developed; computational times could be improved by a factor of 20. Additionally, cost benefits will be realized as commodity graphics hardware could potentially replace expensive supercomputers and high-end workstations. This project will take advantage of the CUDA programming environment and attempt to parallelize the task in such a way that multiple slices of the reconstruction volume are computed simultaneously. This work will also take advantage of the GPU memory by utilizing asynchronous memory transfers, GPU texture memory, and (when possible) pinned host memory so that the memory transfer bottleneck inherent to GPGPU is amortized. Additionally, this work will take advantage of GPU-specific hardware (i.e. fast texture memory, pixel-pipelines, hardware interpolators, and varying memory hierarchy) that will allow for additional performance improvements.

  10. Experimental comparison of grating- and propagation-based hard X-ray phase tomography of soft tissue

    International Nuclear Information System (INIS)

    When imaging soft tissues with hard X-rays, phase contrast is often preferred over conventional attenuation contrast due its superior sensitivity. However, it is unclear which of the numerous phase tomography methods yields the optimized results at given experimental conditions. Therefore, we quantitatively compared the three phase tomography methods implemented at the beamline ID19 of the European Synchrotron Radiation Facility: X-ray grating interferometry (XGI), and propagation-based phase tomography, i.e., single-distance phase retrieval (SDPR) and holotomography (HT), using cancerous tissue from a mouse model and an entire heart of a rat. We show that for both specimens, the spatial resolution derived from the characteristic morphological features is about a factor of two better for HT and SDPR compared to XGI, whereas the XGI data generally exhibit much better contrast-to-noise ratios for the anatomical features. Moreover, XGI excels in fidelity of the density measurements, and is also more robust against low-frequency artifacts than HT, but it might suffer from phase-wrapping artifacts. Thus, we can regard the three phase tomography methods discussed as complementary. The application will decide which spatial and density resolutions are desired, for the imaging task and dose requirements, and, in addition, the applicant must choose between the complexity of the experimental setup and the one of data processing.

  11. Derivation of site-specific relationships between hydraulic parameters and p-wave velocities based on hydraulic and seismic tomography

    Energy Technology Data Exchange (ETDEWEB)

    Brauchler, R.; Doetsch, J.; Dietrich, P.; Sauter, M.

    2012-01-10

    In this study, hydraulic and seismic tomographic measurements were used to derive a site-specific relationship between the geophysical parameter p-wave velocity and the hydraulic parameters, diffusivity and specific storage. Our field study includes diffusivity tomograms derived from hydraulic travel time tomography, specific storage tomograms, derived from hydraulic attenuation tomography, and p-wave velocity tomograms, derived from seismic tomography. The tomographic inversion was performed in all three cases with the SIRT (Simultaneous Iterative Reconstruction Technique) algorithm, using a ray tracing technique with curved trajectories. The experimental set-up was designed such that the p-wave velocity tomogram overlaps the hydraulic tomograms by half. The experiments were performed at a wellcharacterized sand and gravel aquifer, located in the Leine River valley near Göttingen, Germany. Access to the shallow subsurface was provided by direct-push technology. The high spatial resolution of hydraulic and seismic tomography was exploited to derive representative site-specific relationships between the hydraulic and geophysical parameters, based on the area where geophysical and hydraulic tests were performed. The transformation of the p-wave velocities into hydraulic properties was undertaken using a k-means cluster analysis. Results demonstrate that the combination of hydraulic and geophysical tomographic data is a promising approach to improve hydrogeophysical site characterization.

  12. Experimental comparison of grating- and propagation-based hard X-ray phase tomography of soft tissue

    Energy Technology Data Exchange (ETDEWEB)

    Lang, S.; Schulz, G.; Müller, B. [Biomaterials Science Center, University of Basel, Basel (Switzerland); Zanette, I., E-mail: irene.zanette@tum.de [Physik-Department und Institut für Medizintechnik, Technische Universität München, Garching (Germany); European Synchrotron Radiation Facility, Grenoble (France); Dominietto, M. [Biomaterials Science Center, University of Basel, Basel (Switzerland); Institute for Biomedical Engineering, ETH Zürich, Zürich (Switzerland); Langer, M. [European Synchrotron Radiation Facility, Grenoble (France); Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-LYON, Université de Lyon 1, Villeurbane (France); Rack, A.; Le Duc, G. [European Synchrotron Radiation Facility, Grenoble (France); David, C. [Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut, Villigen (Switzerland); Mohr, J. [Institute of Microstructure Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Pfeiffer, F. [Physik-Department und Institut für Medizintechnik, Technische Universität München, Garching (Germany); Weitkamp, T. [European Synchrotron Radiation Facility, Grenoble (France); Synchrotron Soleil, Gif-sur-Yvette (France)

    2014-10-21

    When imaging soft tissues with hard X-rays, phase contrast is often preferred over conventional attenuation contrast due its superior sensitivity. However, it is unclear which of the numerous phase tomography methods yields the optimized results at given experimental conditions. Therefore, we quantitatively compared the three phase tomography methods implemented at the beamline ID19 of the European Synchrotron Radiation Facility: X-ray grating interferometry (XGI), and propagation-based phase tomography, i.e., single-distance phase retrieval (SDPR) and holotomography (HT), using cancerous tissue from a mouse model and an entire heart of a rat. We show that for both specimens, the spatial resolution derived from the characteristic morphological features is about a factor of two better for HT and SDPR compared to XGI, whereas the XGI data generally exhibit much better contrast-to-noise ratios for the anatomical features. Moreover, XGI excels in fidelity of the density measurements, and is also more robust against low-frequency artifacts than HT, but it might suffer from phase-wrapping artifacts. Thus, we can regard the three phase tomography methods discussed as complementary. The application will decide which spatial and density resolutions are desired, for the imaging task and dose requirements, and, in addition, the applicant must choose between the complexity of the experimental setup and the one of data processing.

  13. Fractal analysis of granular ore media based on computed tomography image processing

    Institute of Scientific and Technical Information of China (English)

    WU Ai-xiang; YANG Bao-hua; ZHOU Xu

    2008-01-01

    The cross-sectional images of nine groups of ore samples were obtained by X-ray computed tomography(CT) scanner.Based on CT image analysis,the fractal dimensions of solid matrix,pore space and matrix/pore interface of each sample were measured by using box counting method.The correlation of the three fractal dimensions with particle size,porosity,and seepage coefficient was investigated.The results show that for all images of these samples,the matrix phase has the highest dimension,followed by the pore phase,and the dimension of matrix-pore interface has the smallest value; the dimensions of matrix phase and matrix-pore interface are negatively and linearly correlated with porosity while the dimension of pore phase relates positively and linearly with porosity; the fractal dimension of matrix-pore interface relates negatively and linearly with seepage coefficient.Larger fractal dimension of matrix/pore interface indicates more irregular complicated channels for solution flow,resulting in low permeability.

  14. Use of a Computed Tomography Based Approach to Validate Noninvasive Devices to Measure Rotational Knee Laxity.

    Science.gov (United States)

    Neumann, Simon; Maas, Stefan; Waldmann, Danièle; Ricci, Pierre-Louis; Zürbes, Arno; Arnoux, Pierre-Jean; Walter, Frédéric; Kelm, Jens

    2015-01-01

    The purpose of this study is to validate a noninvasive rotational knee laxity measuring device called "Rotameter P2" with an approach based on Computed Tomography (CT). This CT-approach using X-rays is hence invasive and can be regarded as a precise reference method that may also be applied to similar devices. An error due to imperfect femur fixation was observed but can be neglected for small torques. The most significant estimation error is due to the unavoidable soft tissues rotation and hence flexibility in the measurement chain. The error increases with the applied torque. The assessment showed that the rotational knee angle measured with the Rotameter is still overestimated because of thigh and femur displacement, soft tissues deformation, and measurement artefacts adding up to a maximum of 285% error at +15 Nm for the Internal Rotation of female volunteers. This may be questioned if such noninvasive devices for measuring the Tibia-Femoral Rotation (TFR) can help diagnosing knee pathologies and investigate ligament reconstructive surgery.

  15. NUMERICAL SIMULATION OF ELECTRICAL IMPEDANCE TOMOGRAPHY PROBLEM AND STUDY OF APPROACH BASED ON FINITE VOLUME METHOD

    Directory of Open Access Journals (Sweden)

    Ye. S. Sherina

    2014-01-01

    Full Text Available This research has been aimed to carry out a study of peculiarities that arise in a numerical simulation of the electrical impedance tomography (EIT problem. Static EIT image reconstruction is sensitive to a measurement noise and approximation error. A special consideration has been given to reducing of the approximation error, which originates from numerical implementation drawbacks. This paper presents in detail two numerical approaches for solving EIT forward problem. The finite volume method (FVM on unstructured triangular mesh is introduced. In order to compare this approach, the finite element (FEM based forward solver was implemented, which has gained the most popularity among researchers. The calculated potential distribution with the assumed initial conductivity distribution has been compared to the analytical solution of a test Neumann boundary problem and to the results of problem simulation by means of ANSYS FLUENT commercial software. Two approaches to linearized EIT image reconstruction are discussed. Reconstruction of the conductivity distribution is an ill-posed problem, typically requiring a large amount of computation and resolved by minimization techniques. The objective function to be minimized is constructed of measured voltage and calculated boundary voltage on the electrodes. A classical modified Newton type iterative method and the stochastic differential evolution method are employed. A software package has been developed for the problem under investigation. Numerical tests were conducted on simulated data. The obtained results could be helpful to researches tackling the hardware and software issues for medical applications of EIT.

  16. A novel optical coherence tomography-based micro-indentation technique for mechanical characterization of hydrogels.

    Science.gov (United States)

    Yang, Ying; Bagnaninchi, Pierre O; Ahearne, Mark; Wang, Ruikang K; Liu, Kuo-Kang

    2007-12-22

    Depth-sensing micro-indentation has been well recognized as a powerful tool for characterizing mechanical properties of solid materials due to its non-destructive approach. Based on the depth-sensing principle, we have developed a new indentation method combined with a high-resolution imaging technique, optical coherence tomography, which can accurately measure the deformation of hydrogels under a spherical indenter at constant force. The Hertz contact theory has been applied for quantitatively correlating the indentation force and the deformation with the mechanical properties of the materials. Young's moduli of hydrogels estimated by the new method are comparable with those measured by conventional depth-sensing micro-indentation. The advantages of this new method include its capability to characterize mechanical properties of bulk soft materials and amenability to perform creeping tests. More importantly, the measurement can be performed under sterile conditions allowing non-destructive, in situ and real-time investigations on the changes in mechanical properties of soft materials (e.g. hydrogel). This unique character can be applied for various biomechanical investigations such as monitoring reconstruction of engineered tissues.

  17. Speckle reduction process based on digital filtering and wavelet compounding in optical coherence tomography for dermatology

    Science.gov (United States)

    Gómez Valverde, Juan J.; Ortuño, Juan E.; Guerra, Pedro; Hermann, Boris; Zabihian, Behrooz; Rubio-Guivernau, José L.; Santos, Andrés.; Drexler, Wolfgang; Ledesma-Carbayo, Maria J.

    2015-07-01

    Optical Coherence Tomography (OCT) has shown a great potential as a complementary imaging tool in the diagnosis of skin diseases. Speckle noise is the most prominent artifact present in OCT images and could limit the interpretation and detection capabilities. In this work we propose a new speckle reduction process and compare it with various denoising filters with high edge-preserving potential, using several sets of dermatological OCT B-scans. To validate the performance we used a custom-designed spectral domain OCT and two different data set groups. The first group consisted in five datasets of a single B-scan captured N times (with N<20), the second were five 3D volumes of 25 Bscans. As quality metrics we used signal to noise (SNR), contrast to noise (CNR) and equivalent number of looks (ENL) ratios. Our results show that a process based on a combination of a 2D enhanced sigma digital filter and a wavelet compounding method achieves the best results in terms of the improvement of the quality metrics. In the first group of individual B-scans we achieved improvements in SNR, CNR and ENL of 16.87 dB, 2.19 and 328 respectively; for the 3D volume datasets the improvements were 15.65 dB, 3.44 and 1148. Our results suggest that the proposed enhancement process may significantly reduce speckle, increasing SNR, CNR and ENL and reducing the number of extra acquisitions of the same frame.

  18. Meshless reconstruction method for fluorescence molecular tomography based on compactly supported radial basis function

    Science.gov (United States)

    An, Yu; Liu, Jie; Zhang, Guanglei; Ye, Jinzuo; Mao, Yamin; Jiang, Shixin; Shang, Wenting; Du, Yang; Chi, Chongwei; Tian, Jie

    2015-10-01

    Fluorescence molecular tomography (FMT) is a promising tool in the study of cancer, drug discovery, and disease diagnosis, enabling noninvasive and quantitative imaging of the biodistribution of fluorophores in deep tissues via image reconstruction techniques. Conventional reconstruction methods based on the finite-element method (FEM) have achieved acceptable stability and efficiency. However, some inherent shortcomings in FEM meshes, such as time consumption in mesh generation and a large discretization error, limit further biomedical application. In this paper, we propose a meshless method for reconstruction of FMT (MM-FMT) using compactly supported radial basis functions (CSRBFs). With CSRBFs, the image domain can be accurately expressed by continuous CSRBFs, avoiding the discretization error to a certain degree. After direct collocation with CSRBFs, the conventional optimization techniques, including Tikhonov, L1-norm iteration shrinkage (L1-IS), and sparsity adaptive matching pursuit, were adopted to solve the meshless reconstruction. To evaluate the performance of the proposed MM-FMT, we performed numerical heterogeneous mouse experiments and in vivo bead-implanted mouse experiments. The results suggest that the proposed MM-FMT method can reduce the position error of the reconstruction result to smaller than 0.4 mm for the double-source case, which is a significant improvement for FMT.

  19. Equilibrium based iterative tomography technique for soft-x-ray in W7A stellarator

    International Nuclear Information System (INIS)

    Several algorithms have been developed for x-ray tomography in plasma and applied to the determination of local emissivity distribution at times of particular interest in the discharge (sawteeth, MHD perturbations, disruptions, etc.). Some of these techniques are based on numerical iterative techniques in order to avoid assumptions on emissivity spatial modal structure. They are able to determine any type of structures even those with very localized perturbation, that would require a great number of harmonics, and subsequently a larger amount of detector arrays, in any modal analysis. Iterative numerical techniques have two main drawbacks: high computer time comsumption and possibility of non-real solutions. Trying to avoid them, an iterative method, that uses as initial weights magnetic flux values derived from equilibrium calculations, has been developed. This technique can be applied to any plasma shape and even be used as a 'modified Abel Inversion' when analyzing single array signals. Application using signals from a 30 detector array, have been made for NBI discharges in W7A stellarator, and the obtained reconstructions of local Soft-X-Ray emissivity are compared with theoretical estimations. (author) 2 refs., 4 figs

  20. Simulation of grating-based X-ray phase contrast tomography

    International Nuclear Information System (INIS)

    Grating-based X-ray phase contrast tomography proved to achieve better contrast in soft tissue than conventional X-ray absorption. The real part of the refractive index of the tissue results in a slight deflection of the X-rays. These tiny angles of approximately 20 nrad can be detected by a combination of a phase and absorption gratings. With an absorption grating near the anode of a conventional X-ray tube the method is applicable as part of a medical device. Hence X-ray phase contrast can be used in the detection of soft tissue pathologies e.g. breast tumor in mammography. The application in the clinics demands the lowest dose for the patient though the best contrast to noise ratio (CNR). To accomplish this, we simulated the imaging varying the height and pitch of the gratings for a given power and spectrum of the X-ray tube. Source, detector and grating distances were under the constraint of the dimensions of a putative computer tomograph. Optimal combinations where found for maximal CNR. The results will be important for the design and implementation of the X-ray phase contrast method in commercial CT devices.

  1. Digital-signal-processor-based dynamic imaging system for optical tomography.

    Science.gov (United States)

    Lasker, Joseph M; Masciotti, James M; Schoenecker, Matthew; Schmitz, Christoph H; Hielscher, Andreas H

    2007-08-01

    In this article, we introduce a dynamic optical tomography system that is, unlike currently available analog instrumentation, based on digital data acquisition and filtering techniques. At the core of this continuous wave instrument is a digital signal processor (DSP) that collects, collates, processes, and filters the digitized data set. The processor is also responsible for managing system timing and the imaging routines which can acquire real-time data at rates as high as 150 Hz. Many of the synchronously timed processes are controlled by a complex programmable logic device that is also used in conjunction with the DSP to orchestrate data flow. The operation of the system is implemented through a comprehensive graphical user interface designed with LABVIEW software which integrates automated calibration, data acquisition, data organization, and signal postprocessing. Performance analysis demonstrates very low system noise (approximately 1 pW rms noise equivalent power), excellent signal precision (<0.04%-0.2%) and long term system stability (<1% over 40 min). A large dynamic range (approximately 190 dB) accommodates a wide scope of measurement geometries and tissue types. First experiments on tissue phantoms show that dynamic behavior is accurately captured and spatial location can be correctly tracked using this system.

  2. Atom probe tomography of Ni-base superalloys Allvac 718Plus and Alloy 718.

    Science.gov (United States)

    Viskari, L; Stiller, K

    2011-05-01

    Atom probe tomography (APT) allows near atomic scale compositional- and morphological studies of, e.g. matrix, precipitates and interfaces in a wide range of materials. In this work two Ni-base superalloys with similar compositions, Alloy 718 and its derivative Allvac 718Plus, are subject for investigation with special emphasis on the latter alloy. The structural and chemical nuances of these alloys are important for their properties. Of special interest are grain boundaries as their structure and chemistry are important for the materials' ability to resist rapid environmentally induced crack propagation. APT has proved to be suitable for analyses of these types of alloys using voltage pulsed APT. However, for investigations of specimens containing grain boundaries and other interfaces the risk for early specimen fracture is high. Analyses using laser pulsing impose lower electrical field on the specimen thereby significantly increasing the success rate of investigations. Here, the effect of laser pulsing was studied and the derived appropriate acquisition parameters were then applied for microstructural studies, from which initial results are shown. Furthermore, the influence of the higher evaporation field experienced by the hardening γ' Ni(3)(Al,Nb) precipitates on the obtained results is discussed.

  3. Accelerator-based neutron tomography cooperating with X-ray radiography

    International Nuclear Information System (INIS)

    Neutron resonance absorption spectroscopy (N-RAS) using a pulsed neutron source can be applied to time-of-flight (TOF) radiography, and the obtained parameters from the peak shape analysis can be reconstructed as the tomograms of nuclide distributions using computed tomography (CT). The problem is that the available spatial resolution is not sufficient for radiography imaging. In this study, we combined neutron and X-ray radiographies to improve the quantitative reconstruction of the neutron tomogram. The accelerator-based neutron source emits X-rays (or gamma-rays) at the same time the neutron pulse is emitted. We utilized the X-ray beam from the neutron source to obtain X-ray radiogram on the same beam line with neutron radiography and then reconstructed the neutron tomogram quantitatively with the help of a detailed sample internal structure obtained from the X-ray radiogram. We calculated the nuclide number density distribution tomogram using a statistical reconstruction procedure, which was easy to include in the structure model during the reconstruction. The obtained result of nuclide number density distribution showed good coincidence with the original object number density.

  4. Remote sensing of ionosphere and upper atmosphere based on low-orbital and GNSS radio tomography

    Science.gov (United States)

    Kunitsyn, V.; Tereshchenko, E.; Andreeva, E.; Khudukon, B.; Kozharin, M.; Nazarenko, M.; Nesterov, I.

    A dozen of currently operating multi-point receiving networks that carry out measurements of transmissions from low-orbiting LO navigational systems exists at present in different regions of the world - in Europe America and Asia Numerous radio tomographic RT experiments based on LO satellite systems revealed a complexity and variety of ionospheric structures observed under disturbed and quiet conditions Various shapes of the ionospheric trough were detected A series of specific features in the structure and dynamics of the equatorial anomaly were studied RT images of traveling ionospheric disturbances provided information about the parameters of perturbations and allowed investigation of atmospheric-ionospheric coupling RT study of strong ionospheric disturbances caused by anthropogenic factors in particular by rocket launching industrial explosions powerful high-frequency radiation and so on is performed By means of statistical radio tomography distributions of the intensity of ionospheric plasma fluctuations were retrieved LO RT method allows also determination of plasma fluxes from a time-sequence of RT images of the ionosphere Manifestations of particle precipitation in electron density distributions were observed repeatedly in LO RT images of the ionosphere With a several receiving chains spaced a few hundred kilometer apart it is possible to study the three-dimensional structure of the ionosphere In spite of its high efficiency LO RT employment is basically limited due to the necessity to arrange multi-point receiving systems Deployment of

  5. Hardware Design of Tuber Electrical Resistance Tomography System Based on the Soil Impedance Test and Analysis

    Directory of Open Access Journals (Sweden)

    Liu Shuyi

    2016-01-01

    Full Text Available The hardware design of tuber electrical resistance tomography (TERT system is one of the key research problems of TERT data acquisition system. The TERT system can be applied to the tuber growth process monitoring in agriculture, i.e., the TERT data acquisition system can realize the real imaging of tuber plants in soil. In TERT system, the imaging tuber and soil multiphase medium is quite complexity. So, the impedance test and analysis of soil multiphase medium is very important to the design of sensitive array sensor subsystem and signals processing circuits. In the paper, the soil impedance test experimental is described and the results are analysed. The data acquisition hardware system is designed based on the result of soil medium impedance test and analysis. In the hardware design, the switch control chip ADG508, the instrumentation amplifier AD620 and programmable amplifier AD526 are employed. In the meantime, the phase locked loop technique for signal demodulation is introduced. The initial data collection is given and discussed under the conditions of existing plant tuber and no existing plant tuber. Conclusions of the hardware design of TERT system are presented.

  6. Simulation of grating-based X-ray phase contrast tomography

    Energy Technology Data Exchange (ETDEWEB)

    Achterhold, Klaus; Herzen, Julia; Pfeiffer, Franz [Department of Physics (E17) and Institute of Medical Engineering (IMETUM), Technische Universitaet Muenchen (Germany)

    2011-07-01

    Grating-based X-ray phase contrast tomography proved to achieve better contrast in soft tissue than conventional X-ray absorption. The real part of the refractive index of the tissue results in a slight deflection of the X-rays. These tiny angles of approximately 20 nrad can be detected by a combination of a phase and absorption gratings. With an absorption grating near the anode of a conventional X-ray tube the method is applicable as part of a medical device. Hence X-ray phase contrast can be used in the detection of soft tissue pathologies e.g. breast tumor in mammography. The application in the clinics demands the lowest dose for the patient though the best contrast to noise ratio (CNR). To accomplish this, we simulated the imaging varying the height and pitch of the gratings for a given power and spectrum of the X-ray tube. Source, detector and grating distances were under the constraint of the dimensions of a putative computer tomograph. Optimal combinations where found for maximal CNR. The results will be important for the design and implementation of the X-ray phase contrast method in commercial CT devices.

  7. Detection and analysis of multi-dimensional pulse wave based on optical coherence tomography

    Science.gov (United States)

    Shen, Yihui; Li, Zhifang; Li, Hui; Chen, Haiyu

    2014-11-01

    Pulse diagnosis is an important method of traditional Chinese medicine (TCM). Doctors diagnose the patients' physiological and pathological statuses through the palpation of radial artery for radial artery pulse information. Optical coherence tomography (OCT) is an useful tool for medical optical research. Current conventional diagnostic devices only function as a pressure sensor to detect the pulse wave - which can just partially reflect the doctors feelings and lost large amounts of useful information. In this paper, the microscopic changes of the surface skin above radial artery had been studied in the form of images based on OCT. The deformation of surface skin in a cardiac cycle which is caused by arterial pulse is detected by OCT. The patient's pulse wave is calculated through image processing. It is found that it is good consistent with the result conducted by pulse analyzer. The real-time patient's physiological and pathological statuses can be monitored. This research provides a kind of new method for pulse diagnosis of traditional Chinese medicine.

  8. Fourier optics analysis of phase-mask-based path-length-multiplexed optical coherence tomography.

    Science.gov (United States)

    Yin, Biwei; Dwelle, Jordan; Wang, Bingqing; Wang, Tianyi; Feldman, Marc D; Rylander, Henry G; Milner, Thomas E

    2015-11-01

    Optical coherence tomography (OCT) is an imaging technique that constructs a depth-resolved image by measuring the optical path-length difference between broadband light backscattered from a sample and a reference surface. For many OCT sample arm optical configurations, sample illumination and backscattered light detection share a common path. When a phase mask is placed in the sample path, features in the detected signal are observed, which suggests that an analysis of a generic common path OCT imaging system is warranted. In this study, we present a Fourier optics analysis using a Fresnel diffraction approximation of an OCT system with a path-length-multiplexing element (PME) inserted in the sample arm optics. The analysis may be generalized for most phase-mask-based OCT systems. A radial-angle-diverse PME is analyzed in detail, and the point spread function, coherent transfer function, sensitivity of backscattering angular diversity detection, and signal formation in terms of sample spatial frequency are simulated and discussed. The analysis reveals important imaging features and application limitations of OCT imaging systems with a phase mask in the sample path optics.

  9. Low background high efficiency radiocesium detection system based on positron emission tomography technology

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi; Ogata, Yoshimune [Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya 461-8673 (Japan)

    2013-09-15

    After the 2011 nuclear power plant accident at Fukushima, radiocesium contamination in food became a serious concern in Japan. However, low background and high efficiency radiocesium detectors are expensive and huge, including semiconductor germanium detectors. To solve this problem, we developed a radiocesium detector by employing positron emission tomography (PET) technology. Because {sup 134}Cs emits two gamma photons (795 and 605 keV) within 5 ps, they can selectively be measured with coincidence. Such major environmental gamma photons as {sup 40}K (1.46 MeV) are single photon emitters and a coincidence measurement reduces the detection limit of radiocesium detectors. We arranged eight sets of Bi{sub 4}Ge{sub 3}O{sub 12} (BGO) scintillation detectors in double rings (four for each ring) and measured the coincidence between these detectors using PET data acquisition system. A 50 × 50 × 30 mm BGO was optically coupled to a 2 in. square photomultiplier tube (PMT). By measuring the coincidence, we eliminated most single gamma photons from the energy distribution and only detected those from {sup 134}Cs at an average efficiency of 12%. The minimum detectable concentration of the system for the 100 s acquisition time is less than half of the food monitor requirements in Japan (25 Bq/kg). These results show that the developed radiocesium detector based on PET technology is promising to detect low level radiocesium.

  10. Image-based iterative compensation of motion artifacts in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Schretter, Colas; Rose, Georg; Bertram, Matthias [Philips Research Europe, Weisshausstrasse 2, 52066 Aachen, Germany and Otto-von-Guericke University, Universitaetsplatz 2, 39016 Magdeburg (Germany); Otto-von-Guericke University, Universitaetsplatz 2, 39016 Magdeburg (Germany); Philips Research Europe, Weisshausstrasse 2, 52066 Aachen (Germany)

    2009-11-15

    Purpose: This article presents an iterative method for compensation of motion artifacts for slowly rotating computed tomography (CT) systems. Patient's motion introduces inconsistencies among projections and yields severe reconstruction artifacts for free-breathing acquisitions. Streaks and doubling of structures can appear and the resolution is limited by strong blurring. Methods: The rationale of the proposed motion compensation method is to iteratively correct the reconstructed image by first decomposing the perceived motion in projection space, then reconstructing the motion artifacts in image space, and finally subtracting the artifacts from an initial image. The initial image is reconstructed from the acquired data and might contain motion blur artifacts but, nevertheless, is considered as a reference for estimating the reconstruction artifacts. Results: Qualitative and quantitative figures are shown for experiments based on numerically simulated projections of a sequence of clinical images resulting from a respiratory-gated helical CT acquisition. The border of the diaphragm becomes progressively sharper and the contrast improves for small structures in the lungs. Conclusions: The originality of the technique stems from the fact that the patient motion is not explicitly estimated but the motion artifacts are reconstructed in image space. This approach could provide sharp static anatomical images on interventional C-arm systems or on slowly rotating X-ray equipments in radiotherapy.

  11. High-resolution handheld rigid endomicroscope based on full-field optical coherence tomography

    Science.gov (United States)

    Benoit a la Guillaume, Emilie; Martins, Franck; Boccara, Claude; Harms, Fabrice

    2016-02-01

    Full-field optical coherence tomography (FF-OCT) is a powerful tool for nondestructive assessment of biological tissue, i.e., for the structural examination of tissue in depth at a cellular resolution. Mostly known as a microscopy device for ex vivo analysis, FF-OCT has also been adapted to endoscopy setups since it shows good potential for in situ cancer diagnosis and biopsy guidance. Nevertheless, all the attempts to perform endoscopic FF-OCT imaging did not go beyond lab setups. We describe here, to the best of our knowledge, the first handheld FF-OCT endoscope based on a tandem interferometry assembly using incoherent illumination. A common-path passive imaging interferometer at the tip of an optical probe makes it robust and insensitive to environmental perturbations, and a low finesse Fabry-Perot processing interferometer guarantees a compact system. A good resolution (2.7 μm transverse and 6 μm axial) is maintained through the long distance, small diameter relay optics of the probe, and a good signal-to-noise ratio is achieved in a limited 100 ms acquisition time. High-resolution images and a movie of a rat brain slice have been recorded by moving the contact endoscope over the surface of the sample, allowing for tissue microscopic exploration at 20 μm under the surface. These promising ex vivo results open new perspectives for in vivo imaging of biological tissue, in particular, in the field of cancer and surgical margin assessment.

  12. A novel image-domain-based cone-beam computed tomography enhancement algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiang; Li Tianfang; Yang Yong; Heron, Dwight E; Huq, M Saiful, E-mail: lix@upmc.edu [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232 (United States)

    2011-05-07

    Kilo-voltage (kV) cone-beam computed tomography (CBCT) plays an important role in image-guided radiotherapy. However, due to a large cone-beam angle, scatter effects significantly degrade the CBCT image quality and limit its clinical application. The goal of this study is to develop an image enhancement algorithm to reduce the low-frequency CBCT image artifacts, which are also called the bias field. The proposed algorithm is based on the hypothesis that image intensities of different types of materials in CBCT images are approximately globally uniform (in other words, a piecewise property). A maximum a posteriori probability framework was developed to estimate the bias field contribution from a given CBCT image. The performance of the proposed CBCT image enhancement method was tested using phantoms and clinical CBCT images. Compared to the original CBCT images, the corrected images using the proposed method achieved a more uniform intensity distribution within each tissue type and significantly reduced cupping and shading artifacts. In a head and a pelvic case, the proposed method reduced the Hounsfield unit (HU) errors within the region of interest from 300 HU to less than 60 HU. In a chest case, the HU errors were reduced from 460 HU to less than 110 HU. The proposed CBCT image enhancement algorithm demonstrated a promising result by the reduction of the scatter-induced low-frequency image artifacts commonly encountered in kV CBCT imaging.

  13. FEM-based simulation of a fluorescence tomography experiment using anatomical MR images

    Science.gov (United States)

    Ren, Wuwei; Elmer, Andreas; Augath, Mark-Aurel; Rudin, Markus

    2016-03-01

    A hybrid system combining fluorescence molecular tomography (FMT) and magnetic resonance imaging (MRI) is attractive for preclinical imaging as it allows fusion of molecular information derived from FMT and anatomical reference data derived from MRI. We have previously developed such a system and demonstrated its performance in biological applications. For reconstruction slab geometry with homogeneous optical parameters was assumed, which led to undesirable artifacts. In order to exploit the power of the hybrid system, the use of MRI derived anatomical information, as a constraint for FMT reconstruction, appears logical. Heterogeneity of tissues and irregular surface derived from MRI can be accounted for by generating a mesh using the finite element method (FEM), and attributing optical parameters to individual mesh points. We have established a forward simulation tool based on TOAST++ to mimic an FMT experiment. MRI images were recorded on a 9.4T MR scanner using a T1-weighted pulse sequence. The voxelized dataset was processed by iso2mesh to yield a 3D-mesh. Four steps of FMT simulation were included: 1) Assignment of optical properties, 2) Specification of boundary conditions and generation of 3) excitation and 4) emission maps. FEM-derived results were compared with those obtained using the analytical solution of Green's function and with experimental data with a single fluorescent inclusion in a silicon phantom. Once, the forward modeling method is properly validated it will be used as a central element of a reconstruction algorithm for analyzing data derived from a hybrid FMT/MRI setup.

  14. CdZnTe detector for computed tomography based on weighting potential

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyun Jong; Park, Chan Sun; Kim, Jung Su; Kim, Jung Min; Choi, Jong Hak; Kim, Ki Hyun [Korea University, Seoul (Korea, Republic of)

    2016-03-15

    Room-temperature operating CdZnTe(CZT) material is an innovative radiation detector which could reduce the patient dose to one-tenth level of conventional CT (Computed Tomography) and mammography system. The pixel and pixel pitch in the imaging device determine the conversion efficiency of incident Xor gamma-ray and the cross-talk of signal, that is, image quality of detector system. The weighting potential is the virtual potential determined by the position and geometry of electrode. The weighting potential obtained by computer-based simulation in solving Poisson equation with proper boundaries condition. The pixel was optimized by considering the CIE (charge induced efficiency) and the signal cross-talk in CT detector system. The pixel pitch was 1-mm and the detector thickness was 2-mm in the simulation. The optimized pixel size and inter-pixel distance for maximizing the CIE and minimizing the signal cross-talk is about 750 μm and 125 μm, respectively.

  15. Multispectral excitation based multiple fluorescent targets resolving in fluorescence molecular tomography

    Science.gov (United States)

    Zhou, Yuan; Guang, Huizhi; Pu, Huangsheng; Zhang, Jiulou; Bai, Jing; Luo, Jianwen

    2016-04-01

    Fluorescence molecular tomography (FMT) can visualize biological activities at cellular and molecular levels in vivo, and has been extensively used in drug delivery and tumor detection research of small animals. The ill-posedness of the FMT inverse problem makes it difficult to reconstruct and resolve multiple adjacent fluorescent targets that have different functional features but are labeled with the same fluorochrome. An algorithm based on independent component analysis (ICA) for multispectral excited FMT is proposed to resolve multiple fluorescent targets in this study. Fluorescent targets are excited by multispectral excitation, and the three-dimensional distribution of fluorescent yields under the excitation spectrum is reconstructed by an iterative Tikhonov regularization algorithm. Subsequently, multiple fluorescent targets are resolved from mixed fluorescence signals by employing ICA. Simulations were performed and the results demonstrate that multiple adjacent fluorescent targets can be resolved if the number of excitation wavelengths is not smaller than that of fluorescent targets with different concentrations. The algorithm obtains both independent components that provide spatial information of different fluorescent targets and spectral courses that reflect variation trends of fluorescent yields along with the excitation spectrum. By using this method, it is possible to visualize the metabolism status of drugs in different structure organs, and quantitatively depict the variation trends of fluorescent yields of each functional organ under the excitation spectrum. This method may provide a pattern for tumor detection, drug delivery and treatment monitoring in vivo.

  16. Fast Microwave-Induced Thermoacoustic Tomography Based on Multi-Element Phase-Controlled Focus Technique

    Institute of Scientific and Technical Information of China (English)

    ZENG Lü-Ming; XING Da; GU Huai-Min; YANG Di-Wu; YANG Si-Hua; XIANG Liang-Zhong

    2006-01-01

    @@ We develop a fast microwave-induced thermoacoustic tomography system based on a 320-element phase-controlled focus linear transducer array. A 1.2-GHz microwave generator transmits microwave with a pulse width of 0.5 μs and an incident energy density of 0.45 m J/cm2, and the microwave energy is delivered by a rectangular waveguide with a cross section of (80.01 ± 0.02) × 10-4 m2. Compared to single transducer collection, the system with the multi-element linear transducer array can eliminate the mechanical rotation of the transducer, hence can effectively reduce the image blurring and improve the image resolution. Using a phase-controlled focus technique to collect thermoacoustic signals, the data need not be averaged because of a high signal-to-noise ratio, resulting in a total data acquisition time of less than 5s. The system thus provides a rapid and reliable approach to thermoacoustic imaging, which can potentially be developed as a powerful diagnostic tool for early-stage breast caners.

  17. Classification of temporal bone pneumatization based on sigmoid sinus using computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Han, S.-J. [Department of Otorhinolaryngology, National Health Insurance Corporation Ilsan Hospital, Seoul (Korea, Republic of); Song, M.H. [Department of Otorhinolaryngology, Yonsei University College of Medicine, Kang-nam Gu, Do-gok Dong, 146-92, Seoul, Republic of Korea 135-720 (Korea, Republic of); Kim, J. [Department of Radiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Lee, W.-S. [Department of Otorhinolaryngology, Yonsei University College of Medicine, Kang-nam Gu, Do-gok Dong, 146-92, Seoul, Republic of Korea 135-720 (Korea, Republic of); Lee, H.-K. [Department of Otorhinolaryngology, Yonsei University College of Medicine, Kang-nam Gu, Do-gok Dong, 146-92, Seoul, Republic of Korea 135-720 (Korea, Republic of)], E-mail: hoki@yuhs.ac

    2007-11-15

    Aim: To analyse several reference structures using axial computed tomography (CT) imaging of the temporal bone, which may reflect pneumatization of the entire temporal bone by statistical correlation to the actual volume of the temporal bone measured using three-dimensional reconstruction. Materials and methods: One hundred and sixteen temporal bones were studied, comprising 48 with normal findings and 68 sides showing chronic otitis media or temporal bone fracture. After measuring the volume of temporal bone air cells by the volume rendering technique using three-dimensional reconstruction images, classification of temporal bone pneumatization was performed using various reference structures on axial images to determine whether significant differences in the volume of temporal bone air cells could be found between the groups. Results: When the sigmoid sinus at the level of the malleoincudal complex was used in the classification, there were statistically significant differences between the groups that correlated with the entire volume of the temporal bone. Grouping based on the labyrinth and the ascending carotid artery showed insignificant differences in volume. Furthermore, there was no significant correlation between the cross-sectional area of the antrum and the entire volume of the temporal bone. Conclusion: The degree of pneumatization of temporal bone can be estimated easily by the evaluation of the air cells around the sigmoid sinus on axial CT images.

  18. Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung Won; Lee, Woo Jin; Choi, Soon Chul; Lee, Sam Sun; Heo, Min Suk; Huh, Kyung Hoe; Kim, Tae Il; Yi, Won Ji [Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    2015-03-15

    We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method.

  19. A Bioluminescence Assay System for Imaging Metal Cationic Activities in Urban Aerosols.

    Science.gov (United States)

    Kim, Sung-Bae; Naganawa, Ryuichi; Murata, Shingo; Nakayama, Takayoshi; Miller, Simon; Senda, Toshiya

    2016-01-01

    A bioluminescence-based assay system was fabricated for an efficient determination of the activities of air pollutants. The following four components were integrated into this assay system: (1) an 8-channel assay platform uniquely designed for simultaneously sensing multiple optical samples, (2) single-chain probes illuminating toxic chemicals or heavy metal cations from air pollutants, (3) a microfluidic system for circulating medium mimicking the human body, and (4) the software manimulating the above system. In the protocol, we briefly introduce how to integrate the components into the system and the application to the illumination of the metal cationic activities in air pollutants. PMID:27424913

  20. A Bioluminescence Assay System for Imaging Metal Cationic Activities in Urban Aerosols.

    Science.gov (United States)

    Kim, Sung-Bae; Naganawa, Ryuichi; Murata, Shingo; Nakayama, Takayoshi; Miller, Simon; Senda, Toshiya

    2016-01-01

    A bioluminescence-based assay system was fabricated for an efficient determination of the activities of air pollutants. The following four components were integrated into this assay system: (1) an 8-channel assay platform uniquely designed for simultaneously sensing multiple optical samples, (2) single-chain probes illuminating toxic chemicals or heavy metal cations from air pollutants, (3) a microfluidic system for circulating medium mimicking the human body, and (4) the software manimulating the above system. In the protocol, we briefly introduce how to integrate the components into the system and the application to the illumination of the metal cationic activities in air pollutants.

  1. MRI-Based Computed Tomography Metal Artifact Correction Method for Improving Proton Range Calculation Accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Peter C. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Schreibmann, Eduard; Roper, Justin; Elder, Eric; Crocker, Ian [Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia (United States); Fox, Tim [Varian Medical Systems, Palo Alto, California (United States); Zhu, X. Ronald [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dong, Lei [Scripps Proton Therapy Center, San Diego, California (United States); Dhabaan, Anees, E-mail: anees.dhabaan@emory.edu [Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia (United States)

    2015-03-15

    Purpose: Computed tomography (CT) artifacts can severely degrade dose calculation accuracy in proton therapy. Prompted by the recently increased popularity of magnetic resonance imaging (MRI) in the radiation therapy clinic, we developed an MRI-based CT artifact correction method for improving the accuracy of proton range calculations. Methods and Materials: The proposed method replaces corrupted CT data by mapping CT Hounsfield units (HU number) from a nearby artifact-free slice, using a coregistered MRI. MRI and CT volumetric images were registered with use of 3-dimensional (3D) deformable image registration (DIR). The registration was fine-tuned on a slice-by-slice basis by using 2D DIR. Based on the intensity of paired MRI pixel values and HU from an artifact-free slice, we performed a comprehensive analysis to predict the correct HU for the corrupted region. For a proof-of-concept validation, metal artifacts were simulated on a reference data set. Proton range was calculated using reference, artifactual, and corrected images to quantify the reduction in proton range error. The correction method was applied to 4 unique clinical cases. Results: The correction method resulted in substantial artifact reduction, both quantitatively and qualitatively. On respective simulated brain and head and neck CT images, the mean error was reduced from 495 and 370 HU to 108 and 92 HU after correction. Correspondingly, the absolute mean proton range errors of 2.4 cm and 1.7 cm were reduced to less than 2 mm in both cases. Conclusions: Our MRI-based CT artifact correction method can improve CT image quality and proton range calculation accuracy for patients with severe CT artifacts.

  2. Micro-modulated luminescence tomography

    CERN Document Server

    Cong, Wenxiang; Wang, Chao; Wang, Ge

    2013-01-01

    Imaging depth of optical microscopy has been fundamentally limited to millimeter or sub-millimeter due to light scattering. X-ray microscopy can resolve spatial details of few microns deeply inside a sample but the contrast resolution is still inadequate to depict heterogeneous features at cellular or sub-cellular levels. To enhance and enrich biological contrast at large imaging depth, various nanoparticles are introduced and become essential to basic research and molecular medicine. Nanoparticles can be functionalized as imaging probes, similar to fluorescent and bioluminescent proteins. LiGa5O8:Cr3+ nanoparticles were recently synthesized to facilitate luminescence energy storage with x-ray pre-excitation and the subsequently stimulated luminescence emission by visible/near-infrared (NIR) light. In this paper, we suggest a micro-modulated luminescence tomography (MLT) approach to quantify a nanophosphor distribution in a thick biological sample with high resolution. Our numerical simulation studies demonst...

  3. Concept of a novel fast neutron imaging detector based on THGEM for fan-beam tomography applications

    CERN Document Server

    Cortesi, M; Adams, R; Dangendorf, V; Prasser, H -M

    2012-01-01

    The conceptual design and operational principle of a novel high-efficiency, fast neutron imaging detector based on THGEM, intended for future fan-beam transmission tomography applications, is described. We report on a feasibility study based on theoretical modeling and computer simulations of a possible detector configuration prototype. In particular we discuss results regarding the optimization of detector geometry, estimation of its general performance, and expected imaging quality: it has been estimated that detection efficiency of around 5-8% can be achieved for 2.5MeV neutrons; spatial resolution is around one millimeter with no substantial degradation due to scattering effects. The foreseen applications of the imaging system are neutron tomography in non-destructive testing for the nuclear energy industry, including examination of spent nuclear fuel bundles, detection of explosives or drugs, as well as investigation of thermal hydraulics phenomena (e.g., two-phase flow, heat transfer, phase change, cool...

  4. Concept of a novel fast neutron imaging detector based on THGEM for fan-beam tomography applications

    International Nuclear Information System (INIS)

    The conceptual design and operational principle of a novel high-efficiency, fast neutron imaging detector based on THGEM, intended for future fan-beam transmission tomography applications, is described. We report on a feasibility study based on theoretical modeling and computer simulations of a possible detector configuration prototype. In particular we discuss results regarding the optimization of detector geometry, estimation of its general performance, and expected imaging quality: it has been estimated that detection efficiency of around 5-8% can be achieved for 2.5 MeV neutrons; spatial resolution is around one millimeter with no substantial degradation due to scattering effects. The foreseen applications of the imaging system are neutron tomography in non-destructive testing for the nuclear energy industry, including examination of spent nuclear fuel bundles, detection of explosives or drugs, as well as investigation of thermal hydraulics phenomena (e.g., two-phase flow, heat transfer, phase change, coolant dynamics, and liquid metal flow).

  5. Comparison of Real-Time Intraoperative Ultrasound-Based Dosimetry With Postoperative Computed Tomography-Based Dosimetry for Prostate Brachytherapy

    International Nuclear Information System (INIS)

    Purpose: To evaluate whether real-time intraoperative ultrasound (US)-based dosimetry can replace conventional postoperative computed tomography (CT)-based dosimetry in prostate brachytherapy. Methods and Materials: Between December 2001 and November 2002, 82 patients underwent 103Pd prostate brachytherapy. An interplant treatment planning system was used for real-time intraoperative transrectal US-guided treatment planning. The dose distribution was updated according to the estimated seed position to obtain the dose-volume histograms. Postoperative CT-based dosimetry was performed a few hours later using the Theraplan-Plus treatment planning system. The dosimetric parameters obtained from the two imaging modalities were compared. Results: The results of this study revealed correlations between the US- and CT-based dosimetry. However, large variations were found in the implant-quality parameters of the two modalities, including the doses covering 100%, 90%, and 80% of the prostate volume and prostate volumes covered by 100%, 150%, and 200% of the prescription dose. The mean relative difference was 38% and 16% for doses covering 100% and 90% of the prostate volume and 10% and 21% for prostate volumes covered by 100% and 150% of the prescription dose, respectively. The CT-based volume covered by 200% of the prescription dose was about 30% greater than the US-based one. Compared with CT-based dosimetry, US-based dosimetry significantly underestimated the dose to normal organs, especially for the rectum. The average US-based maximal dose and volume covered by 100% of the prescription dose for the rectum was 72 Gy and 0.01 cm3, respectively, much lower than the 159 Gy and 0.65 cm3 obtained using CT-based dosimetry. Conclusion: Although dosimetry using intraoperative US-based planning provides preliminary real-time information, it does not accurately reflect the postoperative CT-based dosimetry. Until studies have determined whether US-based dosimetry or postoperative CT-based

  6. 3D noninvasive ultrasound Joule heat tomography based on acousto-electric effect using unipolar pulses: a simulation study

    OpenAIRE

    Yang, Renhuan; Li, Xu; Song, Aiguo; He, Bin; Yan, Ruqiang

    2012-01-01

    Electrical properties of biological tissues are highly sensitive to their physiological and pathological status. Thus it is of importance to image electrical properties of biological tissues. However, spatial resolution of conventional electrical impedance tomography (EIT) is generally poor. Recently, hybrid imaging modalities combining electric conductivity contrast and ultrasonic resolution based on acouto-electric effect has attracted considerable attention. In this study, we propose a nov...

  7. Efficacy of Navigation in Skull Base Surgery using Composite Computer Graphics of Magnetic Resonance and Computed Tomography Images

    OpenAIRE

    Hayashi, Nakamasa; Kurimoto, Masanori; Hirashima, Yutaka; Ikeda, Hiroaki; Shibata, Takashi; Tomita, Takahiro; Endo, Shunro

    2001-01-01

    The efficacy of a neurosurgical navigation system using three-dimensional composite computer graphics (CGs) of magnetic resonance (MR) and computed tomography (CT) images was evaluated in skull base surgery. Three-point transformation was used for integration of MR and CT images. MR and CT image data were obtained with three skin markers placed on the patient's scalp. Volume-rendering manipulations of the data produced three-dimensional CGs of the scalp, brain, and lesions from the MR images,...

  8. Multifidus Muscle Volume Estimation Based on Three Dimensional Wavelet Multi Resolution Analysis: MRA with Buttocks Computer-Tomography: CT Images

    OpenAIRE

    Kohei Arai

    2013-01-01

    Multi-Resolution Analysis:. MRA based edge detection algorithm is proposed for estimation of volume of multifidus muscle in the Computer Tomography: CT scanned image The volume of multifidus muscle would be a good measure for metabolic syndrome rather than internal fat from a point of view from processing complexity. The proposed measure shows 0.178 of R square which corresponds to mutual correlation between internal fat and the volume of multifidus muscle. It is also fund that R square betwe...

  9. A promising limited angular computed tomography reconstruction via segmentation based regional enhancement and total variation minimization

    Science.gov (United States)

    Zhang, Wenkun; Zhang, Hanming; Li, Lei; Wang, Linyuan; Cai, Ailong; Li, Zhongguo; Yan, Bin

    2016-08-01

    X-ray computed tomography (CT) is a powerful and common inspection technique used for the industrial non-destructive testing. However, large-sized and heavily absorbing objects cause the formation of artifacts because of either the lack of specimen penetration in specific directions or the acquisition of data from only a limited angular range of views. Although the sparse optimization-based methods, such as the total variation (TV) minimization method, can suppress artifacts to some extent, reconstructing the images such that they converge to accurate values remains difficult because of the deficiency in continuous angular data and inconsistency in the projections. To address this problem, we use the idea of regional enhancement of the true values and suppression of the illusory artifacts outside the region to develop an efficient iterative algorithm. This algorithm is based on the combination of regional enhancement of the true values and TV minimization for the limited angular reconstruction. In this algorithm, the segmentation approach is introduced to distinguish the regions of different image knowledge and generate the support mask of the image. A new regularization term, which contains the support knowledge to enhance the true values of the image, is incorporated into the objective function. Then, the proposed optimization model is solved by variable splitting and the alternating direction method efficiently. A compensation approach is also designed to extract useful information from the initial projections and thus reduce false segmentation result and correct the segmentation support and the segmented image. The results obtained from comparing both simulation studies and real CT data set reconstructions indicate that the proposed algorithm generates a more accurate image than do the other reconstruction methods. The experimental results show that this algorithm can produce high-quality reconstructed images for the limited angular reconstruction and suppress

  10. Dispersion-based stimulated Raman scattering spectroscopy, holography, and optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Robles, Francisco E.; Fischer, Martin C.; Warren, Warren S.

    2016-03-01

    Stimulated Raman scattering (SRS) enables fast, high resolution imaging of chemical constituents important to biological structures and functional processes. While this technology has shown remarkable potential, it is currently limited to point scanning and can only probe a few Raman bands at a time. In this work we take a fundamentally different approach to detecting the small nonlinear signals based on dispersion effects that accompany the loss/gain processes in SRS. We use a modified pump-probe system (pulses with duration of ~0.5 ps and 75 fs, respectively) with interferometric detection in the Fourier-domain to demonstrate that the dispersive measurements are more robust to noise (e.g., laser noise) compared to conventional amplitude measurements, which in turn permits facile spectral and spatial multiplexing. Results show that it is possible to assess a broadband dispersion spectrum (currently limited to ~400 cm-1) with a single laser shot or spectrometer acquisition (20-50 µs). For molecular imaging with broadband spectral information, we achieve spatial pixel rates of 2.5 kHz, and will discuss how this can be further improved to 20-50 kHz. We also combine SRS with optical coherence tomography (OCT) (molecular and structural information are rendered from the same data), which enables axial multiplexing by coherence gating and paves the way for volumetric biochemical imaging. The approach is tested on a thin water-and-oil phantom, a thick scattering polystyrene bead phantom, and thick freshly excised human adipose tissue. Finally, we will outline other opportunities for spatial multiplexing using wide-field holography and spectroscopic-OCT, which would massively parallelize the spatial and spectral information. The combination of dispersion-based SRS and phase imaging has the potential to enable faster wide-area and volumetric molecular imaging. Such methods would be valuable in a clinical setting for many applications.

  11. A novel fully automatic scheme for fiducial marker-based alignment in electron tomography.

    Science.gov (United States)

    Han, Renmin; Wang, Liansan; Liu, Zhiyong; Sun, Fei; Zhang, Fa

    2015-12-01

    Although the topic of fiducial marker-based alignment in electron tomography (ET) has been widely discussed for decades, alignment without human intervention remains a difficult problem. Specifically, the emergence of subtomogram averaging has increased the demand for batch processing during tomographic reconstruction; fully automatic fiducial marker-based alignment is the main technique in this process. However, the lack of an accurate method for detecting and tracking fiducial markers precludes fully automatic alignment. In this paper, we present a novel, fully automatic alignment scheme for ET. Our scheme has two main contributions: First, we present a series of algorithms to ensure a high recognition rate and precise localization during the detection of fiducial markers. Our proposed solution reduces fiducial marker detection to a sampling and classification problem and further introduces an algorithm to solve the parameter dependence of marker diameter and marker number. Second, we propose a novel algorithm to solve the tracking of fiducial markers by reducing the tracking problem to an incomplete point set registration problem. Because a global optimization of a point set registration occurs, the result of our tracking is independent of the initial image position in the tilt series, allowing for the robust tracking of fiducial markers without pre-alignment. The experimental results indicate that our method can achieve an accurate tracking, almost identical to the current best one in IMOD with half automatic scheme. Furthermore, our scheme is fully automatic, depends on fewer parameters (only requires a gross value of the marker diameter) and does not require any manual interaction, providing the possibility of automatic batch processing of electron tomographic reconstruction.

  12. Gamma camera based Positron Emission Tomography: a study of the viability on quantification

    International Nuclear Information System (INIS)

    Positron Emission Tomography (PET) is a Nuclear Medicine imaging modality for diagnostic purposes. Pharmaceuticals labeled with positron emitters are used and images which represent the in vivo biochemical process within tissues can be obtained. The positron/electron annihilation photons are detected in coincidence and this information is used for object reconstruction. Presently, there are two types of systems available for this imaging modality: the dedicated systems and those based on gamma camera technology. In this work, we utilized PET/SPECT systems, which also allows for the traditional Nuclear Medicine studies based on single photon emitters. There are inherent difficulties which affect quantification of activity and other indices. They are related to the Poisson nature of radioactivity, to radiation interactions with patient body and detector, noise due to statistical nature of these interactions and to all the detection processes, as well as the patient acquisition protocols. Corrections are described in the literature and not all of them are implemented by the manufacturers: scatter, attenuation, random, decay, dead time, spatial resolution, and others related to the properties of each equipment. The goal of this work was to assess these methods adopted by two manufacturers, as well as the influence of some technical characteristics of PET/SPECT systems on the estimation of SUV. Data from a set of phantoms were collected in 3D mode by one camera and 2D, by the other. We concluded that quantification is viable in PET/SPECT systems, including the estimation of SUVs. This is only possible if, apart from the above mentioned corrections, the camera is well tuned and coefficients for sensitivity normalization and partial volume corrections are applied. We also verified that the shapes of the sources used for obtaining these factors play a role on the final results and should be delt with carefully in clinical quantification. Finally, the choice of the region

  13. Studying primate carpal kinematics in three dimensions using a computed-tomography-based markerless registration method.

    Science.gov (United States)

    Orr, Caley M; Leventhal, Evan L; Chivers, Spencer F; Marzke, Mary W; Wolfe, Scott W; Crisco, Joseph J

    2010-04-01

    The functional morphology of the wrist pertains to a number of important questions in primate evolutionary biology, including that of hominins. Reconstructing locomotor and manipulative capabilities of the wrist in extinct species requires a detailed understanding of wrist biomechanics in extant primates and the relationship between carpal form and function. The kinematics of carpal movement, and the role individual joints play in providing mobility and stability of the wrist, is central to such efforts. However, there have been few detailed biomechanical studies of the nonhuman primate wrist. This is largely because of the complexity of wrist morphology and the considerable technical challenges involved in tracking the movements of the many small bones that compose the carpus. The purpose of this article is to introduce and outline a method adapted from human clinical studies of three-dimensional (3D) carpal kinematics for use in a comparative context. The method employs computed tomography of primate cadaver forelimbs in increments throughout the wrist's range of motion, coupled with markerless registration of 3D polygon models based on inertial properties of each bone. The 3D kinematic principles involved in extracting motion axis parameters that describe bone movement are reviewed. In addition, a set of anatomically based coordinate systems embedded in the radius, capitate, hamate, lunate, and scaphoid is presented for the benefit of other primate functional morphologists interested in studying carpal kinematics. Finally, a brief demonstration of how the application of these methods can elucidate the mechanics of the wrist in primates illustrates the closer-packing of carpals in chimpanzees than in orangutans, which may help to stabilize the midcarpus and produce a more rigid wrist beneficial for efficient hand posturing during knuckle-walking locomotion.

  14. Image processing for femoral endosteal anatomy detection: description and testing of a computed tomography based program

    International Nuclear Information System (INIS)

    A computed tomography (CT)-based image processing computer program was developed for three-dimensional (3D) femoral endosteal cavity shape modelling. For the examinations 50 cadaver femora were used. In the CT imaging 30 axial slices were taken above and below the lesser trochanter area from each femur. Different image analysis methods were used for femoral cavity detection depending on the structure of the processed slice. In the femoral shaft area simple thresholding methods succeeded, but in the problem areas of the metaphyseal femur edge, detection operators and local thresholding were required. In contour tracking several criteria were used to check the validity of the border pixels. The results were saved as four output data files: (i) a file for the longest anteroposterior (ap), ediolateral (ml) and oblique diameters computed by a Euclidian method, (ii) nd (iii) files for 2D and 3D data respectively, and (iv) a file for centre points of each slice. Finally, testing of the results and dimensions obtained from the image analysis were carried out manually by sawing the femora into 0 stipulated horizontal slices. The ap and ml dimensions were measured with caliper ruler. The CT-based image processing yielded a peak distribution of dimensions with a negative difference to those obtained in manual measurements. The mean difference between the image processing and the manual measurements was 1.1 mm (±0.7 mm, ±1 SD). The difference was highest in he proximal slices of the femora of group I (with lowest cortical thickness), i.e. 1.3 mm (±0.8 mm) and lowest in the distal slices of the femora from group III (with highest cortical thickness), i.e. 0.9 mm (±0.6 m). The results are acceptable for further use of the program to study endosteal anatomy for individual femoral component selection and designing asis. (author)

  15. Bioluminescent system for dynamic imaging of cell and animal behavior

    Energy Technology Data Exchange (ETDEWEB)

    Hara-Miyauchi, Chikako [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN, Saitama 351-0198 (Japan); Department of Biophysics and Biochemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo 113-8510 (Japan); Tsuji, Osahiko [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582 (Japan); Hanyu, Aki [Division of Biochemistry, The Cancer Institute of the Japanese Foundation for Cancer Research, Tokyo 135-8550 (Japan); Okada, Seiji [Department of Advanced Medical Initiatives, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8582 (Japan); Yasuda, Akimasa [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582 (Japan); Fukano, Takashi [Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN, Saitama 351-0198 (Japan); Akazawa, Chihiro [Department of Biophysics and Biochemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo 113-8510 (Japan); Nakamura, Masaya [Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582 (Japan); Imamura, Takeshi [Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295 (Japan); Core Research for Evolutional Science and Technology, The Japan Science and Technology Corporation, Tokyo 135-8550 (Japan); Matsuzaki, Yumi [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Okano, Hirotaka James, E-mail: hjokano@jikei.ac.jp [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Division of Regenerative Medicine Jikei University School of Medicine, Tokyo 150-8461 (Japan); and others

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer We combined a yellow variant of GFP and firefly luciferase to make ffLuc-cp156. Black-Right-Pointing-Pointer ffLuc-cp156 showed improved photon yield in cultured cells and transgenic mice. Black-Right-Pointing-Pointer ffLuc-cp156 enabled video-rate bioluminescence imaging of freely-moving animals. Black-Right-Pointing-Pointer ffLuc-cp156 mice enabled tracking real-time drug delivery in conscious animals. -- Abstract: The current utility of bioluminescence imaging is constrained by a low photon yield that limits temporal sensitivity. Here, we describe an imaging method that uses a chemiluminescent/fluorescent protein, ffLuc-cp156, which consists of a yellow variant of Aequorea GFP and firefly luciferase. We report an improvement in photon yield by over three orders of magnitude over current bioluminescent systems. We imaged cellular movement at high resolution including neuronal growth cones and microglial cell protrusions. Transgenic ffLuc-cp156 mice enabled video-rate bioluminescence imaging of freely moving animals, which may provide a reliable assay for drug distribution in behaving animals for pre-clinical studies.

  16. Filtering and deconvolution for bioluminescence imaging of small animals

    International Nuclear Information System (INIS)

    This thesis is devoted to analysis of bioluminescence images applied to the small animal. This kind of imaging modality is used in cancerology studies. Nevertheless, some problems are related to the diffusion and the absorption of the tissues of the light of internal bioluminescent sources. In addition, system noise and the cosmic rays noise are present. This influences the quality of the images and makes it difficult to analyze. The purpose of this thesis is to overcome these disturbing effects. We first have proposed an image formation model for the bioluminescence images. The processing chain is constituted by a filtering stage followed by a deconvolution stage. We have proposed a new median filter to suppress the random value impulsive noise which corrupts the acquired images; this filter represents the first block of the proposed chain. For the deconvolution stage, we have performed a comparative study of various deconvolution algorithms. It allowed us to choose a blind deconvolution algorithm initialized with the estimated point spread function of the acquisition system. At first, we have validated our global approach by comparing our obtained results with the ground truth. Through various clinical tests, we have shown that the processing chain allows a significant improvement of the spatial resolution and a better distinction of very close tumor sources, what represents considerable contribution for the users of bioluminescence images. (author)

  17. The influence of SHFEMF on bioluminescence of V. Harveyi

    International Nuclear Information System (INIS)

    Exposure of bacteria V. harveyi grown on agar medium to 7 HHz electromagnetic field changes the intensity of their luminescence. It is suggested that the dynamics of the luminescence change reflects the adaptation processes in the microorganisms which accompany the electromao.netic field effect. The changes observed may be attributed to the temperature dependence of bioluminescence

  18. Bioluminescent system for dynamic imaging of cell and animal behavior

    International Nuclear Information System (INIS)

    Highlights: ► We combined a yellow variant of GFP and firefly luciferase to make ffLuc-cp156. ► ffLuc-cp156 showed improved photon yield in cultured cells and transgenic mice. ► ffLuc-cp156 enabled video-rate bioluminescence imaging of freely-moving animals. ► ffLuc-cp156 mice enabled tracking real-time drug delivery in conscious animals. -- Abstract: The current utility of bioluminescence imaging is constrained by a low photon yield that limits temporal sensitivity. Here, we describe an imaging method that uses a chemiluminescent/fluorescent protein, ffLuc-cp156, which consists of a yellow variant of Aequorea GFP and firefly luciferase. We report an improvement in photon yield by over three orders of magnitude over current bioluminescent systems. We imaged cellular movement at high resolution including neuronal growth cones and microglial cell protrusions. Transgenic ffLuc-cp156 mice enabled video-rate bioluminescence imaging of freely moving animals, which may provide a reliable assay for drug distribution in behaving animals for pre-clinical studies.

  19. The mechanism of electronic excitation in the bacterial bioluminescent reaction

    International Nuclear Information System (INIS)

    The current state of the problem of formation of the electron-excited product in the chemiluminescent reaction that underlies the bacterial luminescence is analysed. Various schemes of chemical transformations capable of producing a bacterial bioluminescence emitter are presented. The problem of excitation of secondary emitters is considered; two possible mechanisms of their excitation are analysed.

  20. Role of certain amino acid residues of the coelenterazine-binding cavity in bioluminescence of light-sensitive Ca(2+)-regulated photoprotein berovin.

    Science.gov (United States)

    Burakova, Ludmila P; Stepanyuk, Galina A; Eremeeva, Elena V; Vysotski, Eugene S

    2016-05-11

    Bright bioluminescence of ctenophores is caused by Ca(2+)-regulated photoproteins. Although these photoproteins are functionally identical to and share many properties of cnidarian photoproteins, like aequorin and obelin, and retain the same spatial architecture, they are extremely sensitive to light, i.e. lose the ability to bioluminesce on exposure to light over the entire absorption spectrum. In addition, the degree of identity of their amino acid sequences with those of cnidarian photoproteins is only 29.4%. This suggests that the residues involved in bioluminescence of ctenophore and cnidarian photoproteins significantly differ. Here we describe the bioluminescent properties of berovin mutants with substitution of the residues located in the photoprotein internal cavity. Since the spatial structure of berovin bound with a substrate is not determined yet, to identify these residues we have modeled it with an accommodated substrate using the structures of some cnidarian Ca(2+)-regulated photoproteins with bound coelenterazine or coelenteramide as templates in order to obtain an adequate sampling and to take into account all possible conformers and variants for ligand-protein docking. Based on the impact of substitutions on the bioluminescent properties and model structures we speculate that within the internal cavity of ctenophore photoproteins, coelenterazine is bound as a 2-peroxy anion adduct which is stabilized owing to Coulomb interaction with a positively charged guanidinium group of Arg41 paired with Tyr204. In this case, the bioluminescence reaction is triggered by only calcium-induced conformational changes leading to the disturbance of charge-charge interaction. PMID:27117544

  1. Tomographic bioluminescence imaging by use of a combined optical-PET (OPET) system: a computer simulation feasibility study

    OpenAIRE

    Alexandrakis, George; Rannou, Fernando R; Chatziioannou, Arion F

    2005-01-01

    The feasibility and limits in performing tomographic bioluminescence imaging with a combined optical-PET (OPET) system was explored by simulating its image formation process. A micro-MRI based virtual mouse phantom was assigned appropriate tissue optical properties to each of its segmented internal organs at wavelengths spanning the emission spectrum of the firefly luciferase at 37 °C. The TOAST finite-element code was employed to simulate the diffuse transport of photons emitted from biolumi...

  2. Bayesian Multi-Energy Computed Tomography reconstruction approaches based on decomposition models

    International Nuclear Information System (INIS)

    Multi-Energy Computed Tomography (MECT) makes it possible to get multiple fractions of basis materials without segmentation. In medical application, one is the soft-tissue equivalent water fraction and the other is the hard-matter equivalent bone fraction. Practical MECT measurements are usually obtained with polychromatic X-ray beams. Existing reconstruction approaches based on linear forward models without counting the beam poly-chromaticity fail to estimate the correct decomposition fractions and result in Beam-Hardening Artifacts (BHA). The existing BHA correction approaches either need to refer to calibration measurements or suffer from the noise amplification caused by the negative-log pre-processing and the water and bone separation problem. To overcome these problems, statistical DECT reconstruction approaches based on non-linear forward models counting the beam poly-chromaticity show great potential for giving accurate fraction images.This work proposes a full-spectral Bayesian reconstruction approach which allows the reconstruction of high quality fraction images from ordinary polychromatic measurements. This approach is based on a Gaussian noise model with unknown variance assigned directly to the projections without taking negative-log. Referring to Bayesian inferences, the decomposition fractions and observation variance are estimated by using the joint Maximum A Posteriori (MAP) estimation method. Subject to an adaptive prior model assigned to the variance, the joint estimation problem is then simplified into a single estimation problem. It transforms the joint MAP estimation problem into a minimization problem with a non-quadratic cost function. To solve it, the use of a monotone Conjugate Gradient (CG) algorithm with suboptimal descent steps is proposed.The performances of the proposed approach are analyzed with both simulated and experimental data. The results show that the proposed Bayesian approach is robust to noise and materials. It is also

  3. Far-red fluorescence gene reporter tomography for determination of placement and viability of cell-based gene therapies.

    Science.gov (United States)

    Lu, Yujie; Darne, Chinmay D; Tan, I-Chih; Zhu, Banghe; Hall, Mary A; Lazard, Zawaunyka W; Davis, Alan R; Simpson, Lashan; Sevick-Muraca, Eva M; Olmsted-Davis, Elizabeth A

    2013-10-01

    Non-invasive injectable cellular therapeutic strategies based on sustained delivery of physiological levels of BMP-2 for spinal fusion are emerging as promising alternatives, which could provide sufficient fusion without the associated surgical risks. However, these injectable therapies are dependent on bone formation occurring only at the specific target region. In this study, we developed and deployed fluorescence gene reporter tomography (FGRT) to provide information on in vivo cell localization and viability. This information is sought to confirm the ideal placement of the materials with respect to the area where early bone reaction is required, ultimately providing three dimensional data about the future fusion. However, because almost all conventional fluorescence gene reporters require visible excitation wavelengths, current in vivo imaging of fluorescent proteins is limited by high tissue absorption and confounding autofluorescence. We previously administered fibroblasts engineered to produce BMP-2, but is difficult to determine 3-D information of placement prior to bone formation. Herein we used the far-red fluorescence gene reporter, IFP1.4 to report the position and viability of fibroblasts and developed 3-D tomography to provide placement information. A custom small animal, far-red fluorescence tomography system integrated into a commercial CT scanner was used to assess IFP1.4 fluorescence and to demark 3-D placement of encapsulated fibroblasts with respect to the vertebrae and early bone formation as assessed from CT. The results from three experiments showed that the placement of the materials within the spine could be detected. This work shows that in vivo fluorescence gene reporter tomography of cell-based gene therapy is feasible and could help guide cell-based therapies in preclinical models.

  4. Polydiacetylene Liposomal Aequorin Bioluminescent Device for Detection of Hydrophobic Compounds.

    Science.gov (United States)

    Yamamoto, Ryoko; Takegami, Shigehiko; Konishi, Atsuko; Horikawa, Hikari; Yonezawa, Sayumi; Kitade, Tatsuya

    2016-06-01

    In this study, a polydiacetylene liposomal aequorin bioluminescent device (PLABD) that functioned through control of the membrane transport of Ca(2+) ions was developed for detecting hydrophobic compounds. In the PLABD, aequorin was encapsulated in an internal water phase and a calcium ionophore (CI) was contained in a hydrophobic region. Membrane transport of Ca(2+) ions across the CI was suppressed by polymerization between diacetylene molecules. On addition of an analyte, the membrane transport of Ca(2+) ions across the CI increased, and Ca(2+) ions from the external water phase could diffuse into the internal water phase via the CI, which resulted in bioluminescence of the aequorin. Lidocaine, procaine, and procainamide were used as model compounds to test the validity of the detection mechanism of the PLABD. When each analyte was added to a suspension of the PLABD, bioluminescence from the aequorin in the PLABD was observed, and the level of this bioluminescence increased with increasing analyte concentration. There was a linear relationship between the logarithm of the analyte concentration and the bioluminescence for all analytes as follows: R = 0.89 from 10 nmol L(-1) to 10 mmol L(-1) for lidocaine, R = 0.66 from 10 nmol L(-1) to 100 μmol L(-1) for procaine, and R = 0.74 from 100 nmol L(-1) to 100 μmol L(-1) for procainamide. Compared to the traditional colorimetric method using polydiacetylene liposome, the PLABD was superior for both the sensitivity and dynamic range. Thus, PLABD is a valid, simple, and sensitive signal generator for detection of hydrophobic compounds that interact with PLABD membranes. PMID:27146598

  5. Boosting bioluminescence neuroimaging: an optimized protocol for brain studies.

    Science.gov (United States)

    Aswendt, Markus; Adamczak, Joanna; Couillard-Despres, Sebastien; Hoehn, Mathias

    2013-01-01

    Bioluminescence imaging is widely used for optical cell tracking approaches. However, reliable and quantitative bioluminescence of transplanted cells in the brain is highly challenging. In this study we established a new bioluminescence imaging protocol dedicated for neuroimaging, which increases sensitivity especially for noninvasive tracking of brain cell grafts. Different D-Luciferin concentrations (15, 150, 300 and 750 mg/kg), injection routes (i.v., i.p., s.c.), types of anesthesia (Isoflurane, Ketamine/Xylazine, Pentobarbital) and timing of injection were compared using DCX-Luc transgenic mice for brain specific bioluminescence. Luciferase kinetics was quantitatively evaluated for maximal photon emission, total photon emission and time-to-peak. Photon emission followed a D-Luciferin dose-dependent relation without saturation, but with delay in time-to-peak increasing for increasing concentrations. The comparison of intravenous, subcutaneous and intraperitoneal substrate injection reflects expected pharmacokinetics with fastest and highest photon emission for intravenous administration. Ketamine/Xylazine and Pentobarbital anesthesia showed no significant beneficial effect on maximal photon emission. However, a strong difference in outcome was observed by injecting the substrate pre Isoflurane anesthesia. This protocol optimization for brain specific bioluminescence imaging comprises injection of 300 mg/kg D-Luciferin pre Isoflurane anesthesia as an efficient and stable method with a signal gain of approx. 200% (compared to 150 mg/kg post Isoflurane). Gain in sensitivity by the novel imaging protocol was quantitatively assessed by signal-to-noise calculations of luciferase-expressing neural stem cells grafted into mouse brains (transplantation of 3,000-300,000 cells). The optimized imaging protocol lowered the detection limit from 6,000 to 3,000 cells by a gain in signal-to-noise ratio.

  6. Parallel algorithm based on a frequency decomposition for dynamic three dimensional computed tomography

    International Nuclear Information System (INIS)

    Dynamic X ray tomography is a new medical imaging modality. In conventional scanner, a static cross-section of the patient is reconstructed from a set of x-ray projection acquired from the rotation around the patient of a X ray source and a set of detectors. In dynamic tomography a set of successive cross sections is reconstructed enabling the imaging of naturally moving organs such as the heart or organs in dynamic interaction with exterior elements. This is the case for CAS (computer assisted surgery) where we would like to control under CT imaging the progression of surgical tools (example: peri-cardiac punction). The diffusion of a contrast product (ex in angiography), or of a marker in nuclear imaging can also be studied dynamically. Thus dynamic tomography is becoming a very promising tool for the diagnostic of disease, the study of their evolution but also for guiding surgeons during CAS. (author)

  7. Imaging Liver Lesions Using Grating-Based Phase-Contrast Computed Tomography with Bi-Lateral Filter Post-Processing

    OpenAIRE

    Herzen, Julia; Marian S Willner; Fingerle, Alexander A.; Peter B Noël; Köhler, Thomas; Drecoll, Enken; Rummeny, Ernst J.; Pfeiffer, Franz

    2014-01-01

    X-ray phase-contrast imaging shows improved soft-tissue contrast compared to standard absorption-based X-ray imaging. Especially the grating-based method seems to be one promising candidate for clinical implementation due to its extendibility to standard laboratory X-ray sources. Therefore the purpose of our study was to evaluate the potential of grating-based phase-contrast computed tomography in combination with a novel bi-lateral denoising method for imaging of focal liver lesions in an ex...

  8. Light illumination and detection patterns for fluorescence diffuse optical tomography based on compressive sensing.

    Science.gov (United States)

    Jin, An; Yazici, Birsen; Ntziachristos, Vasilis

    2014-06-01

    Fluorescence diffuse optical tomography (FDOT) is an emerging molecular imaging modality that uses near infrared light to excite the fluorophore injected into tissue; and to reconstruct the fluorophore concentration from boundary measurements. The FDOT image reconstruction is a highly ill-posed inverse problem due to a large number of unknowns and limited number of measurements. However, the fluorophore distribution is often very sparse in the imaging domain since fluorophores are typically designed to accumulate in relatively small regions. In this paper, we use compressive sensing (CS) framework to design light illumination and detection patterns to improve the reconstruction of sparse fluorophore concentration. Unlike the conventional FDOT imaging where spatially distributed light sources illuminate the imaging domain one at a time and the corresponding boundary measurements are used for image reconstruction, we assume that the light sources illuminate the imaging domain simultaneously several times and the corresponding boundary measurements are linearly filtered prior to image reconstruction. We design a set of optical intensities (illumination patterns) and a linear filter (detection pattern) applied to the boundary measurements to improve the reconstruction of sparse fluorophore concentration maps. We show that the FDOT sensing matrix can be expressed as a columnwise Kronecker product of two matrices determined by the excitation and emission light fields. We derive relationships between the incoherence of the FDOT forward matrix and these two matrices, and use these results to reduce the incoherence of the FDOT forward matrix. We present extensive numerical simulation and the results of a real phantom experiment to demonstrate the improvements in image reconstruction due to the CS-based light illumination and detection patterns in conjunction with relaxation and greedy-type reconstruction algorithms.

  9. Noise properties of grating-based x-ray phase contrast computed tomography

    International Nuclear Information System (INIS)

    Purpose: To investigate the properties of tomographic grating-based phase contrast imaging with respect to its noise power spectrum and the energy dependence of the achievable contrast to noise ratio. Methods: Tomographic simulations of an object with 11 cm diameter constituted of materials of biological interest were conducted at different energies ranging from 25 to 85 keV by using a wave propagation approach. Using a Monte Carlo simulation of the x-ray attenuation within the object, it is verified that the simulated measurement deposits the same dose within the object at each energy. Results: The noise in reconstructed phase contrast computed tomography images shows a maximum at low spatial frequencies. The contrast to noise ratio reaches a maximum around 45 keV for the simulated object. The general dependence of the contrast to noise on the energy appears to be independent of the material. Compared with reconstructed absorption contrast images, the reconstructed phase contrast images show sometimes better, sometimes worse, and sometimes similar contrast to noise, depending on the material and the energy. Conclusions: Phase contrast images provide additional information to the conventional absorption contrast images and might thus be useful for medical applications. However, the observed noise power spectrum in reconstructed phase contrast images implies that the usual trade-off between noise and resolution is less efficient for phase contrast imaging compared with absorption contrast imaging. Therefore, high-resolution imaging is a strength of phase contrast imaging, but low-resolution imaging is not. This might hamper the clinical application of the method, in cases where a low spatial resolution is sufficient for diagnosis.

  10. A new linear back projection algorithm to electrical tomography based on measuring data decomposition

    International Nuclear Information System (INIS)

    As an advanced measurement technique of non-radiant, non-intrusive, rapid response, and low cost, the electrical tomography (ET) technique has developed rapidly in recent decades. The ET imaging algorithm plays an important role in the ET imaging process. Linear back projection (LBP) is the most used ET algorithm due to its advantages of dynamic imaging process, real-time response, and easy realization. But the LBP algorithm is of low spatial resolution due to the natural ‘soft field’ effect and ‘ill-posed solution’ problems; thus its applicable ranges are greatly limited. In this paper, an original data decomposition method is proposed, and every ET measuring data are decomposed into two independent new data based on the positive and negative sensing areas of the measuring data. Consequently, the number of total measuring data is extended to twice as many as the number of the original data, thus effectively reducing the ‘ill-posed solution’. On the other hand, an index to measure the ‘soft field’ effect is proposed. The index shows that the decomposed data can distinguish between different contributions of various units (pixels) for any ET measuring data, and can efficiently reduce the ‘soft field’ effect of the ET imaging process. In light of the data decomposition method, a new linear back projection algorithm is proposed to improve the spatial resolution of the ET image. A series of simulations and experiments are applied to validate the proposed algorithm by the real-time performances and the progress of spatial resolutions. (paper)

  11. A novel forward projection-based metal artifact reduction method for flat-detector computed tomography

    Science.gov (United States)

    Prell, Daniel; Kyriakou, Yiannis; Beister, Marcel; Kalender, Willi A.

    2009-11-01

    Metallic implants generate streak-like artifacts in flat-detector computed tomography (FD-CT) reconstructed volumetric images. This study presents a novel method for reducing these disturbing artifacts by inserting discarded information into the original rawdata using a three-step correction procedure and working directly with each detector element. Computation times are minimized by completely implementing the correction process on graphics processing units (GPUs). First, the original volume is corrected using a three-dimensional interpolation scheme in the rawdata domain, followed by a second reconstruction. This metal artifact-reduced volume is then segmented into three materials, i.e. air, soft-tissue and bone, using a threshold-based algorithm. Subsequently, a forward projection of the obtained tissue-class model substitutes the missing or corrupted attenuation values directly for each flat detector element that contains attenuation values corresponding to metal parts, followed by a final reconstruction. Experiments using tissue-equivalent phantoms showed a significant reduction of metal artifacts (deviations of CT values after correction compared to measurements without metallic inserts reduced typically to below 20 HU, differences in image noise to below 5 HU) caused by the implants and no significant resolution losses even in areas close to the inserts. To cover a variety of different cases, cadaver measurements and clinical images in the knee, head and spine region were used to investigate the effectiveness and applicability of our method. A comparison to a three-dimensional interpolation correction showed that the new approach outperformed interpolation schemes. Correction times are minimized, and initial and corrected images are made available at almost the same time (12.7 s for the initial reconstruction, 46.2 s for the final corrected image compared to 114.1 s and 355.1 s on central processing units (CPUs)).

  12. Small field dose delivery evaluations using cone beam optical computed tomography-based polymer gel dosimetry

    Directory of Open Access Journals (Sweden)

    Timothy Olding

    2011-01-01

    Full Text Available This paper explores the combination of cone beam optical computed tomography with an N-isopropylacrylamide (NIPAM-based polymer gel dosimeter for three-dimensional dose imaging of small field deliveries. Initial investigations indicate that cone beam optical imaging of polymer gels is complicated by scattered stray light perturbation. This can lead to significant dosimetry failures in comparison to dose readout by magnetic resonance imaging (MRI. For example, only 60% of the voxels from an optical CT dose readout of a 1 l dosimeter passed a two-dimensional Low′s gamma test (at a 3%, 3 mm criteria, relative to a treatment plan for a well-characterized pencil beam delivery. When the same dosimeter was probed by MRI, a 93% pass rate was observed. The optical dose measurement was improved after modifications to the dosimeter preparation, matching its performance with the imaging capabilities of the scanner. With the new dosimeter preparation, 99.7% of the optical CT voxels passed a Low′s gamma test at the 3%, 3 mm criteria and 92.7% at a 2%, 2 mm criteria. The fitted interjar dose responses of a small sample set of modified dosimeters prepared (a from the same gel batch and (b from different gel batches prepared on the same day were found to be in agreement to within 3.6% and 3.8%, respectively, over the full dose range. Without drawing any statistical conclusions, this experiment gives a preliminary indication that intrabatch or interbatch NIPAM dosimeters prepared on the same day should be suitable for dose sensitivity calibration.

  13. Validation of constitutively expressed bioluminescent Pseudomonas aeruginosa as a rapid microbiological quantification tool.

    Science.gov (United States)

    Shah, N; Naseby, D C

    2015-06-15

    Whole cell biosensors have been extensively used for monitoring toxicity and contamination of various compounds and xenobiotics in environmental biology and microbial ecology; their application in the pharmaceutical and cosmetics industries has been limited. According to several pharmacopoeias, pharmaceutical products must be tested for microbial activity using traditional viable count techniques; the use of whole cell microbial biosensors potentially provides an alternative, fast, and efficient method. However there is a lack of a validated bioluminescence method. Prototype whole cell microbial biosensors have already been developed in Pseudomonas aeruginosa ATCC 9027. Validation of the bioluminescent strains was performed in accordance with the pharmacopoeia, Parenteral Drug Association and International Organisation of Standardisation. These strains demonstrated that the bioluminescent method was accurate, precise and equivalent, as compared with plate counting at a range of 10(3)-10(7) CFU/mL. Percentage recoveries using the bioluminescent method were between 70% and 130% for all bioluminescent strains and therefore the bioluminescent method was accurate according to the criteria set in PDA technical report 33. The method was also more precise (relative standard deviation less than 15%) than the traditional plate counting method or the ATP bioluminescent method. The lower limit of detection was 10(3) CFU/mL. Two-way ANOVA showed no significant difference between the traditional plate counting and the novel bioluminescent method for all bioluminescent strains. The bioluminescent constructs passed/exceeded pharmacopoeia-specified criteria for range, limit of detection, accuracy, precision and equivalence.

  14. Characterization of nano-sized precipitates in a Mn-based lean maraging steel by atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Millan, J.; Ponge, D.; Raabe, D.; Choi, P.; Dmitrieva, O. [Max-Planck-Institut fuer Eisenforschung, Duesseldorf (Germany)

    2011-02-15

    We present atom probe tomography results of a precipitation-hardened Mn-based maraging steel (9 Mn, 1.9 Ni, 0.6 Mo, 1.1 Ti, 0.33 Al; in at.%). The alloy is characterized by the surprising effect that both, strength and total elongation increase upon aging. The material reveals a high ultimate tensile strength (UTS) up to 1 GPa and good ductility (total elongation (TE) of up to 15% in a tensile test) depending on aging conditions. We map the evolution of the precipitates after 450 C aging treatment using atom probe tomography in terms of chemical composition and size distribution. (Copyright copyright 2011 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. A fast cross-validation method for alignment of electron tomography images based on Beer-Lambert law.

    Science.gov (United States)

    Yan, Rui; Edwards, Thomas J; Pankratz, Logan M; Kuhn, Richard J; Lanman, Jason K; Liu, Jun; Jiang, Wen

    2015-11-01

    In electron tomography, accurate alignment of tilt series is an essential step in attaining high-resolution 3D reconstructions. Nevertheless, quantitative assessment of alignment quality has remained a challenging issue, even though many alignment methods have been reported. Here, we report a fast and accurate method, tomoAlignEval, based on the Beer-Lambert law, for the evaluation of alignment quality. Our method is able to globally estimate the alignment accuracy by measuring the goodness of log-linear relationship of the beam intensity attenuations at different tilt angles. Extensive tests with experimental data demonstrated its robust performance with stained and cryo samples. Our method is not only significantly faster but also more sensitive than measurements of tomogram resolution using Fourier shell correlation method (FSCe/o). From these tests, we also conclude that while current alignment methods are sufficiently accurate for stained samples, inaccurate alignments remain a major limitation for high resolution cryo-electron tomography.

  16. Bioimpedance-based respiratory gating method for oncologic positron emission tomography (PET) imaging with first clinical results

    Science.gov (United States)

    Koivumäki, T.; Vauhkonen, M.; Teuho, J.; Teräs, M.; Hakulinen, M. A.

    2013-04-01

    Respiratory motion may cause significant image artefacts in positron emission tomography/computed tomography (PET/CT) imaging. This study introduces a new bioimpedance-based gating method for minimizing respiratory artefacts. The method was studied in 12 oncologic patients by evaluating the following three parameters: maximum metabolic activity of radiopharmaceutical accumulations, the size of these targets as well as their target-to-background ratio. The bioimpedance-gated images were compared with non-gated images and images that were gated with a reference method, chest wall motion monitoring by infrared camera. The bioimpedance method showed clear improvement as increased metabolic activity and decreased target volume compared to non-gated images and produced consistent results with the reference method. Thus, the method may have great potential in the future of respiratory gating in nuclear medicine imaging.

  17. Bioimpedance-based respiratory gating method for oncologic positron emission tomography (PET) imaging with first clinical results

    International Nuclear Information System (INIS)

    Respiratory motion may cause significant image artefacts in positron emission tomography/computed tomography (PET/CT) imaging. This study introduces a new bioimpedance-based gating method for minimizing respiratory artefacts. The method was studied in 12 oncologic patients by evaluating the following three parameters: maximum metabolic activity of radiopharmaceutical accumulations, the size of these targets as well as their target-to-background ratio. The bioimpedance-gated images were compared with non-gated images and images that were gated with a reference method, chest wall motion monitoring by infrared camera. The bioimpedance method showed clear improvement as increased metabolic activity and decreased target volume compared to non-gated images and produced consistent results with the reference method. Thus, the method may have great potential in the future of respiratory gating in nuclear medicine imaging.

  18. Influence of antibiotic pressure on bacterial bioluminescence, with emphasis on Staphylococcus aureus.

    Science.gov (United States)

    Daghighi, Seyedmojtaba; Sjollema, Jelmer; Harapanahalli, Akshay; Dijkstra, Rene J B; van der Mei, Henny C; Busscher, Henk J

    2015-12-01

    Bioluminescence imaging is used for longitudinal evaluation of bacteria in live animals. Clear relations exist between bacterial numbers and their bioluminescence. However, bioluminescence images of Staphylococcus aureus Xen29, S. aureus Xen36 and Escherichia coli Xen14 grown on tryptone soy agar in Etests demonstrated increased bioluminescence at sub-MICs of different antibiotics. This study aimed to further evaluate the influence of antibiotic pressure on bioluminescence in S. aureus Xen29. Bioluminescence of S. aureus Xen29, grown planktonically in tryptone soy broth, was quantified in the absence and presence of different concentrations of vancomycin, ciprofloxacin, erythromycin or chloramphenicol and was related to expression of the luxA gene under antibiotic pressure measured using real-time PCR. In the absence of antibiotics, staphylococcal bioluminescence increased over time until a maximum after ca. 6h of growth, and subsequently decreased to the detection threshold after 24h of growth owing to reduced bacterial metabolic activity. Up to MICs of the antibiotics, bioluminescence increased according to a similar pattern up to 6h of growth, but after 24h bioluminescence was higher than in the absence of antibiotics. Contrary to expectations, bioluminescence per organism (CFU) after different growth periods in the absence and at MICs of different antibiotics decreased with increasing expression of luxA. Summarising, antibiotic pressure impacts the relation between CFU and bioluminescence. Under antibiotic pressure, bioluminescence is not controlled by luxA expression but by co-factors impacting the bacterial metabolic activity. This conclusion is of utmost importance when evaluating antibiotic efficacy in live animals using bioluminescent bacterial strains.

  19. Three-dimensional registration of synchrotron radiation-based micro-computed tomography images with advanced laboratory micro-computed tomography data from murine kidney casts

    Science.gov (United States)

    Thalmann, Peter; Hieber, Simone E.; Schulz, Georg; Deyhle, Hans; Khimchenko, Anna; Kurtcuoglu, Vartan; Olgac, Ufuk; Marmaras, Anastasios; Kuo, Willy; Meyer, Eric P.; Beckmann, Felix; Herzen, Julia; Ehrbar, Stefanie; Müller, Bert

    2014-09-01

    Malfunction of oxygen regulation in kidney and liver may lead to the pathogenesis of chronic diseases. The underlying mechanisms are poorly understood. In kidney, it is hypothesized that renal gas shunting from arteries to veins eliminates excess oxygen. Such shunting is highly dependent on the structure of the renal vascular network. The vascular tree has so far not been quantified under maintenance of its connectivity as three-dimensional imaging of the vessel tree down to the smallest capillaries, which in mouse model are smaller than 5 μm in diameter, is a challenging task. An established protocol uses corrosion casts and applies synchrotron radiation-based micro-computed tomography (SRμCT), which provides the desired spatial resolution with the necessary contrast. However, SRμCT is expensive and beamtime access is limited. We show here that measurements with a phoenix nanotomrm (General Electric, Wunstorf, Germany) can provide comparable results to those obtained with SRμCT, except for regions with small vessel structures, where the signal-to-noise level was significantly reduced. For this purpose the nanotom®m measurement was compared with its corresponding measurement acquired at the beamline P05 at PETRA III at DESY, Hamburg, Germany.

  20. A correlation-based misfit criterion for wave-equation traveltime tomography

    NARCIS (Netherlands)

    Van Leeuwen, T.; Mulder, W.A.

    2010-01-01

    Wave-equation traveltime tomography tries to obtain a subsurface velocity model from seismic data, either passive or active, that explains their traveltimes. A key step is the extraction of traveltime differences, or relative phase shifts, between observed and modelled finite-frequency waveforms. A

  1. Application of bioluminescence ATP measurement for evaluation of fungal viability of foxing spots on old documents.

    Science.gov (United States)

    Rakotonirainy, Malalanirina Sylvia; Dubar, Pauline

    2013-01-01

    An adenosine triphosphate (ATP) bioluminescence-based protocol was tested to assess the viability of fungal species in old documents damaged by foxing. Foxing appears as scattered yellow brownish-red stains, damaging the aesthetics of documents and their long-term readability. In the field of cultural heritage conservation, the debate over the mechanism of foxing is ongoing. Previous studies found evidence of mold-like structures in some coloured areas; however, many species have not yet been identified and their role in the phenomenon is not understood. To better understand their involvement in this type of paper decay, we focused our attention first on their viability. We demonstrated the reliability and sensitivity of the ATP bioluminescence assay compared with conventional methods based on cultivation, which has rarely given rise to in vitro growth from foxed papers. From nine books dating back from the 19th and 20th centuries, the mean ATP amount of foxed spots ranged from 0.29 to 3.63 ng/cm(2), suggesting the presence of strains inside the brownish spots and providing evidence of their viability. Outside the spots, ATP content was considered negligible, with a mean ATP amount of 0 to 0.03 ng/cm(2). ATP assay appears to be a useful and robust method for the detection and quantification of viable elements in foxing spots.

  2. Borehole radar diffraction tomography

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seong Jun; Kim, Jung Ho; Yi, Myeong Jong; Chung, Seung Hwan; Lee, Hee Il [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1997-12-01

    Tomography is widely used as imaging method for determining subsurface structure. Among the reconstruction algorithms for tomographic imaging, travel time tomography is almost applied to imaging subsurface. But isolated small body comparable with the wavelength could not be well recognized by travel time tomography. Other tomographic method are need to improve the imaging process. In the study of this year, diffraction tomography was investigated. The theory for diffraction tomography is based on the 1st-order Born approximation. Multisource holography, which is similar to Kirchihoff migration, is compared with diffraction tomography. To improve 1st-order Born diffraction tomography, two kinds of filter designed from multisource holography and 2-D green function, respectively, applied on the reconstructed image. The algorithm was tested for the numerical modeling data of which algorithm consists of the analytic computation of radar signal in transmitter and receiver regions and 2-D FDM scheme for the propagation of electromagnetic waves in media. The air-filled cavity model to show a typical diffraction pattern was applied to diffraction tomography imaging, and the result shows accurate location and area of cavity. But the calculated object function is not well matched the real object function, because the air-filled cavity model is not satisfied week scattered inhomogeneity for 1st born approximation, and the error term is included in estimating source wavelet from received signals. In spite of the object function error, the diffraction tomography assist for interpretation of subsurface as if conducted with travel time tomography. And the fracture model was tested, 1st born diffraction tomographic image is poor because of limited view angle coverage and violation of week scatter assumption, but the filtered image resolve the fracture somewhat better. The tested diffraction tomography image confirms effectiveness of filter for enhancing resolution. (author). 14

  3. Effect of concentrating and exposing the bioluminescent bacteria to the non-luminescent allo-bacterial extracellular products on their luminescence

    Digital Repository Service at National Institute of Oceanography (India)

    Ravindran, J.; Priya, G.G.; Kannapiran, E.

    Bioluminescence is a biochemical process occurring in many organisms. Bacterial bioluminescence has been investigated extensively that lead to many applications of such knowledge. Quorum sensing in the bioluminescent bacteria is a chemical signal...

  4. Information-theoretic discrepancy based iterative reconstructions (IDIR) for polychromatic x-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Kwang Eun; Lee, Jongha; Sung, Younghun; Lee, SeongDeok [Advanced Media Laboratory, Samsung Advanced Institute of Technology (SAIT), San 14, Nongseo Dong, Giheung Gu, Yongin, Gyeonggi 446-712 (Korea, Republic of)

    2013-09-15

    Purpose: X-ray photons generated from a typical x-ray source for clinical applications exhibit a broad range of wavelengths, and the interactions between individual particles and biological substances depend on particles' energy levels. Most existing reconstruction methods for transmission tomography, however, neglect this polychromatic nature of measurements and rely on the monochromatic approximation. In this study, we developed a new family of iterative methods that incorporates the exact polychromatic model into tomographic image recovery, which improves the accuracy and quality of reconstruction.Methods: The generalized information-theoretic discrepancy (GID) was employed as a new metric for quantifying the distance between the measured and synthetic data. By using special features of the GID, the objective function for polychromatic reconstruction which contains a double integral over the wavelength and the trajectory of incident x-rays was simplified to a paraboloidal form without using the monochromatic approximation. More specifically, the original GID was replaced with a surrogate function with two auxiliary, energy-dependent variables. Subsequently, the alternating minimization technique was applied to solve the double minimization problem. Based on the optimization transfer principle, the objective function was further simplified to the paraboloidal equation, which leads to a closed-form update formula. Numerical experiments on the beam-hardening correction and material-selective reconstruction were conducted to compare and assess the performance of conventional methods and the proposed algorithms.Results: The authors found that the GID determines the distance between its two arguments in a flexible manner. In this study, three groups of GIDs with distinct data representations were considered. The authors demonstrated that one type of GIDs that comprises “raw” data can be viewed as an extension of existing statistical reconstructions; under a

  5. In vivo visualization and monitoring of viable neural stem cells using noninvasive bioluminescence imaging in the 6-hydroxydopamine-induced mouse model of Parkinson disease.

    Science.gov (United States)

    Im, Hyung-Jun; Hwang, Do Won; Lee, Han Kyu; Jang, Jaeho; Lee, Song; Youn, Hyewon; Jin, Yeona; Kim, Seung U; Kim, E Edmund; Kim, Yong Sik; Lee, Dong Soo

    2013-06-01

    Transplantation of neural stem cells (NSCs) has been proposed as a treatment for Parkinson disease (PD). The aim of this study was to monitor the viability of transplanted NSCs expressing the enhanced luciferase gene in a mouse model of PD in vivo. The PD animal model was induced by unilateral injection of 6-hydroxydopamine (6-OHDA). The behavioral test using apomorphine-induced rotation and positron emission tomography with [18F]N-(3-fluoropropyl)-2'-carbomethoxy-3'-(4-iodophenyl)nortropane ([18F]FP-CIT) were conducted. HB1.F3 cells transduced with an enhanced firefly luciferase retroviral vector (F3-effLuc cells) were transplanted into the right striatum. In vivo bioluminescence imaging was repeated for 2 weeks. Four weeks after transplantation, [18F]FP-CIT PET and the rotation test were repeated. All 6-OHDA-injected mice showed markedly decreased [18F]FP-CIT uptake in the right striatum. Transplanted F3-effLuc cells were visualized on the right side of the brain in all mice by bioluminescence imaging. The bioluminescence intensity of the transplanted F3-effLuc cells gradually decreased until it was undetectable by 10 days. The behavioral test showed that stem cell transplantation attenuated the motor symptoms of PD. No significant change was found in [18F]FP-CIT imaging after cell transplantation. We successfully established an in vivo bioluminescence imaging system for the detection of transplanted NSCs in a mouse model of PD. NSC transplantation induced behavioral improvement in PD model mice.

  6. Modelling dinoflagellates as an approach to the seasonal forecasting of bioluminescence in the North Atlantic

    Science.gov (United States)

    Marcinko, Charlotte L. J.; Martin, Adrian P.; Allen, John T.

    2014-11-01

    Bioluminescence within ocean surface waters is of significant interest because it can enhance the study of subsurface movement and organisms. Little is known about how bioluminescence potential (BPOT) varies spatially and temporally in the open ocean. However, light emitted from dinoflagellates often dominates the stimulated bioluminescence field. As a first step towards forecasting surface ocean bioluminescence in the open ocean, a simple ecological model is developed which simulates seasonal changes in dinoflagellate abundance. How forecasting seasonal changes in BPOT may be achieved through combining such a model with relationships derived from observations is discussed and an example is given. The study illustrates a potential new approach to forecasting BPOT through explicitly modelling the population dynamics of a prolific bioluminescent phylum. The model developed here offers a promising platform for the future operational forecasting of the broad temporal changes in bioluminescence within the North Atlantic. Such forecasting of seasonal patterns could provide valuable information for the targeting of scientific field campaigns.

  7. Real-time monitoring of bioaerosols via cell-lysis by air ion and ATP bioluminescence detection.

    Science.gov (United States)

    Park, Chul Woo; Park, Ji-Woon; Lee, Sung Hwa; Hwang, Jungho

    2014-02-15

    In this study, we introduce a methodology for disrupting cell membranes with air ions coupled with ATP bioluminescence detection for real-time monitoring of bioaerosol concentrations. A carbon fiber ionizer was used to extract ATP from bacterial cells for generating ATP bioluminescence. Our methodology was tested using Staphylococcus epidermidis and Escherichia coli, which were aerosolized with an atomizer, and then indoor bioaerosols were also used for testing the methodology. Bioaerosol concentrations were estimated without culturing which requires several days for colony formation. Correlation equations were obtained for results acquired using our methodology (Relative Luminescent Unit (RLU)/m(3)) and a culture-based (Colony Forming Unit (CFU)/m(3)) method; CFU/m(3)=1.8 × measured RLU/m(3) for S. epidermidis and E. coli, and CFU/m(3)=1.1 × measured RLU/m(3) for indoor bioaerosols under the experimental conditions. Our methodology is an affordable solution for rapidly monitoring bioaerosols due to rapid detection time (cell-lysis time: 3 min; bioluminescence detection time: <1 min) and easy operation.

  8. Efficacy of Lantibiotic Treatment of Staphylococcus aureus-Induced Skin Infections, Monitored by In Vivo Bioluminescent Imaging.

    Science.gov (United States)

    van Staden, Anton Du Preez; Heunis, Tiaan; Smith, Carine; Deane, Shelly; Dicks, Leon M T

    2016-07-01

    Staphylococcus aureus is a bacterial pathogen responsible for the majority of skin and soft tissue infections. Antibiotics are losing their efficacy as treatment for skin and soft tissue infections as a result of increased resistance in a variety of pathogens, including S. aureus It is thus imperative to explore alternative antimicrobial treatments to ensure future treatment options for skin and soft tissue infections. A select few lantibiotics, a group of natural defense peptides produced by bacteria, inhibit the growth of numerous clinical S. aureus isolates, including methicillin-resistant strains. In this study, the antimicrobial activities of nisin, clausin, and amyloliquecidin, separately administered, were compared to that of a mupirocin-based ointment, which is commonly used as treatment for S. aureus-induced skin infections. Full-thickness excisional wounds, generated on the dorsal surfaces of mice, were infected with a bioluminescent strain of S. aureus (strain Xen 36). The infections were monitored in real time using in vivo bioluminescent imaging. Lantibiotic treatments significantly reduced the bioluminescence of S. aureus Xen 36 to a level similar to that recorded with mupirocin treatment. Wound closure, however, was more pronounced during lantibiotic treatment. Lantibiotics thus have the potential to be used as an alternative treatment option for S. aureus-induced skin infections. PMID:27067340

  9. Exploiting in vitro and in vivo bioluminescence for the implementation of the three Rs principle (replacement, reduction, and refinement) in drug discovery.

    Science.gov (United States)

    Michelini, Elisa; Cevenini, Luca; Calabretta, Maria Maddalena; Calabria, Donato; Roda, Aldo

    2014-09-01

    Bioluminescence-based analytical tools are suitable for high-throughput and high-content screening assays, finding widespread application in several fields related to the drug discovery process. Cell-based bioluminescence assays, because of their peculiar advantages of predictability, possibility of automation, multiplexing, and miniaturization, seem the most appealing tool for the high demands of the early stages of drug screening. Reporter gene technology and the bioluminescence resonance energy transfer principle are widely used, and receptor binding studies of new agonists/antagonists for a variety of human receptors expressed in different cell lines can be performed. Moreover, bioluminescence can be used for in vitro and in vivo real-time monitoring of pathophysiological processes within living cells and small animals. New luciferases and substrates have recently arrived on the market, further expanding the spectrum of applications. A new generation of probes are also emerging that promise to revolutionize the preclinical imaging market. This formidable toolbox is demonstrated to facilitate the implementation of the three Rs principle in the early drug discovery process, in compliance with ethical and responsible research to reduce cost and improve the reliability and predictability of results.

  10. Impact of Anesthesia Protocols on In Vivo Bioluminescent Bacteria Imaging Results

    OpenAIRE

    Chuzel, Thomas; Sanchez, Violette; Vandamme, Marc; Martin, Stéphane; Flety, Odile; Pager, Aurélie; Chabanel, Christophe; Magnier, Luc; Foskolos, Marie; Petit, Océane; Rokbi, Bachra; Chereul, Emmanuel

    2015-01-01

    Infectious murine models greatly benefit from optical imaging using bioluminescent bacteria to non-invasively and repeatedly follow in vivo bacterial infection. In this context, one of the most critical parameters is the bioluminescence sensitivity to reliably detect the smallest number of bacteria. Another critical point is the anesthetic approaches that have been demonstrated to impact the bioluminescence flux emission in studies with luciferase-transfected tumor cells. However, this impact...

  11. A study on bioluminescence and photoluminescence in the earthworm Eisenia lucens.

    Science.gov (United States)

    Pes, O; Midlik, A; Schlaghamersky, J; Zitnan, M; Taborsky, P

    2016-02-01

    Eisenia lucens is an earthworm living in the organic soil layer of decomposing wood. When irritated, the worm expels coelomic fluid through pores in its body wall, exhibiting blue-green bioluminescence. The mechanism of the bioluminescence, which seems to be different from other bioluminescence systems of terrestrial animals, has been studied in this work. Many lines of evidence indicate that riboflavin stored in coelomycetes plays an important role in this glowing reaction.

  12. Water Vapour GNSS Based Tomography For Wet Delay Compensation In In-SAR Applications

    Science.gov (United States)

    Notarpietro, Riccardo; Cucca, Manuela; Perona, Giovanni

    2010-05-01

    One of the most challenging exploitation of GNSS signals for meteorological applications is the retrieval of Water Vapor tridimensional distribution. The real-time (or quasi real-time) knowledge of such distributions could be very useful for several applications: from operative meteorology to atmospheric modeling, or for atmospheric compensation purposes applied for example to SAR or In-SAR observations, in order to improve land remote sensing. In the framework of the European Space Agency project METAWAVE (Mitigation of Electromagnetic Transmission errors induced by Atmospheric Water Vapor Effects), several techniques were investigated in order to find out an In-SAR data compensation strategy for the propagation delay effects due to Water Vapour. Thanks to METAWAVE, a quite dense GPS network (7 dual frequency GPS receivers) was deployed over COMO area and was used for an extensive measurement campaign. The acquired L1 and L2 carrier phase observations were processed in terms of hourly averaged Zenith Wet Delays. These vertical information were mapped along the correspondent line of sights (by up-sampling at 30 second sample times the 15 minutes GPS satellites positions obtained from IGS files) and inverted using a tomographic procedure. The used algorithm performs a first reconstruction (namely, the tomographic pre-processing) based on generalized inversion mechanisms, in order to define a low resolution first guess for the next step. This second step inverts GPS observables using a more refined algebraic tomographic reconstruction algorithm, to improve both vertical and horizontal resolution. Results of this inversion are Wet Refractivity maps distributed over an area of 16 km x 20 km (x 10 km height) around the COMO city, characterized by horizontal resolutions varying from 2 km to 4 km and vertical resolution of 500m. This contribution deals with the description of the results obtained evaluating Water Vapour path delays from such Wet Refractivity maps

  13. Optimization of recommendations for abdomen computerized tomography based on reconstruction filters, voltage and tube current

    International Nuclear Information System (INIS)

    The use of computed tomography has increased significantly over the past decades. In Brazil the use increased more than twofold from 2008 to 2014, in the meantime the abdomen procedures have tripled. The high frequency of this procedure combined by the increasing collective radiation dose in medical exposures, has resulted development tools to maximize the benefit in CT images. This work aimed to establish protocols optimized in abdominal CT through acquisitions parameters and reconstructions techniques based on filters kernels. A sample of patients undergoing abdominal CT in a diagnostic center of Rio de Janeiro was assessed. Had been collected patients information and acquisitions parameters. The phantoms CT image acquisitions were performed by using different voltage values by adjusting the tube current (mAs) to obtain the same value from CTDIvol patients with normal BMI. Afterwards, the CTDIvol values were reduced by 30%, 50% and 60%. All images were reconstructed with low-contrast filters (A) and standard filters (B). The CTDIvol values for patients with normal BMI were 7% higher than in patients with underweight BMI and 30%, 50% and 60% lower than the overweight, obese I and III patients, respectively. The evaluations of image quality showed that variation of the current (mA) and the reconstruction filters did not affect the Hounsfield values. When the contrast-to-noise ratio (CNR) was normalized to CTDIvol, the protocols acquired with 60% reduction of CTDIvol with 140 kV and 80 kV showed CNR 6% lower than the routine. Modifications of the acquisition parameters did not affect spatial resolution, but the post-processing with B filters reduced the spatial frequency by 16%. With reduced the dose of 30%, lesions in the spleen had the CNR higher than 10% routine protocols with 140 kV acquired and post-processed to filter A. The image post-processing with a filter A with a 80kV voltage provided CNR values equal to the routine for the liver lesions with a 30

  14. A novel image reconstruction methodology based on inverse Monte Carlo analysis for positron emission tomography

    Science.gov (United States)

    Kudrolli, Haris A.

    2001-04-01

    A three dimensional (3D) reconstruction procedure for Positron Emission Tomography (PET) based on inverse Monte Carlo analysis is presented. PET is a medical imaging modality which employs a positron emitting radio-tracer to give functional images of an organ's metabolic activity. This makes PET an invaluable tool in the detection of cancer and for in-vivo biochemical measurements. There are a number of analytical and iterative algorithms for image reconstruction of PET data. Analytical algorithms are computationally fast, but the assumptions intrinsic in the line integral model limit their accuracy. Iterative algorithms can apply accurate models for reconstruction and give improvements in image quality, but at an increased computational cost. These algorithms require the explicit calculation of the system response matrix, which may not be easy to calculate. This matrix gives the probability that a photon emitted from a certain source element will be detected in a particular detector line of response. The ``Three Dimensional Stochastic Sampling'' (SS3D) procedure implements iterative algorithms in a manner that does not require the explicit calculation of the system response matrix. It uses Monte Carlo techniques to simulate the process of photon emission from a source distribution and interaction with the detector. This technique has the advantage of being able to model complex detector systems and also take into account the physics of gamma ray interaction within the source and detector systems, which leads to an accurate image estimate. A series of simulation studies was conducted to validate the method using the Maximum Likelihood - Expectation Maximization (ML-EM) algorithm. The accuracy of the reconstructed images was improved by using an algorithm that required a priori knowledge of the source distribution. Means to reduce the computational time for reconstruction were explored by using parallel processors and algorithms that had faster convergence rates

  15. Seismic structure of the European upper mantle based on adjoint tomography

    Science.gov (United States)

    Zhu, Hejun; Bozdağ, Ebru; Tromp, Jeroen

    2015-04-01

    We use adjoint tomography to iteratively determine seismic models of the crust and upper mantle beneath the European continent and the North Atlantic Ocean. Three-component seismograms from 190 earthquakes recorded by 745 seismographic stations are employed in the inversion. Crustal model EPcrust combined with mantle model S362ANI comprise the 3-D starting model, EU00. Before the structural inversion, earthquake source parameters, for example, centroid moment tensors and locations, are reinverted based on global 3-D Green's functions and Fréchet derivatives. This study consists of three stages. In stage one, frequency-dependent phase differences between observed and simulated seismograms are used to constrain radially anisotropic wave speed variations. In stage two, frequency-dependent phase and amplitude measurements are combined to simultaneously constrain elastic wave speeds and anelastic attenuation. In these two stages, long-period surface waves and short-period body waves are combined to simultaneously constrain shallow and deep structures. In stage three, frequency-dependent phase and amplitude anomalies of three-component surface waves are used to simultaneously constrain radial and azimuthal anisotropy. After this three-stage inversion, we obtain a new seismic model of the European curst and upper mantle, named EU60. Improvements in misfits and histograms in both phase and amplitude help us to validate this three-stage inversion strategy. Long-wavelength elastic wave speed variations in model EU60 compare favourably with previous body- and surface wave tomographic models. Some hitherto unidentified features, such as the Adria microplate, naturally emerge from the smooth starting model. Subducting slabs, slab detachments, ancient suture zones, continental rifts and backarc basins are well resolved in model EU60. We find an anticorrelation between shear wave speed and anelastic attenuation at depths global attenuation studies. Furthermore, enhanced

  16. Ambient seismic noise tomography of SW Iberia integrating seafloor- and land-based data

    Science.gov (United States)

    Corela, Carlos; Silveira, Graça; Matias, Luís; Schimmel, Martin; Geissler, Wolfram

    2016-04-01

    We used ambient seismic noise recorded by 24 broadband ocean bottom seismometers (OBS-BB) deployed in in the Gulf of Cadiz during the EC funded NEAREST project and seven broadband land stations located in the South of Portugal to image the sedimentary and crustal structure beneath the Eastern Atlantic and SW Iberia. We computed ambient noise cross-correlations to obtain empirical Green's functions (EGFs) between all station pairs, and using both sort of sensors, namely seismometers and hydrophones. Despite the great difference between the crustal structure below beneath OBSs and land stations and the recording conditions, we were able to compute high signal-to-noise ratio EGFs, by applying a linear cross-correlation with a running absolute mean average time normalization, followed by a time-frequency phase weighted stack. Dispersion analysis was then applied to the EGFs, between 4 and 20s period. The obtained 395 reliable group velocity dispersion curves, between all station pairs, allowed mapping the lateral variation of Rayleigh wave group velocities, as a function of period. Finally, dispersion curves extracted from each cell of the 2D group velocity maps were inverted, as a function of depth, to obtain the 3D distribution of the shear-wave velocities. The 3-D shear wave velocity model, computed from joint inversion of OBS and land stations data allowed to estimate the thickness of sediments and crust and the Moho depth. Although, we could perceive the impact of the spatial gap between OBSs and land stations, our model displays a good correlation with the main geological features. The main results on the sedimentary layer thickness and on the Moho depth are in agreement with the model proposed by other studies using observations from multi-beam bathymetry and seismic profiling, thus confirming that, not only that ambient noise tomography is a valuable tool to image oceanic domains, but also that we can integrate seafloor- and land-based stations. Publication

  17. Detection of Antibodies in Blood Plasma Using Bioluminescent Sensor Proteins and a Smartphone.

    Science.gov (United States)

    Arts, Remco; den Hartog, Ilona; Zijlema, Stefan E; Thijssen, Vito; van der Beelen, Stan H E; Merkx, Maarten

    2016-04-19

    Antibody detection is of fundamental importance in many diagnostic and bioanalytical assays, yet current detection techniques tend to be laborious and/or expensive. We present a new sensor platform (LUMABS) based on bioluminescence resonance energy transfer (BRET) that allows detection of antibodies directly in solution using a smartphone as the sole piece of equipment. LUMABS are single-protein sensors that consist of the blue-light emitting luciferase NanoLuc connected via a semiflexible linker to the green fluorescent acceptor protein mNeonGreen, which are kept close together using helper domains. Binding of an antibody to epitope sequences flanking the linker disrupts the interaction between the helper domains, resulting in a large decrease in BRET efficiency. The resulting change in color of the emitted light from green-blue to blue can be detected directly in blood plasma, even at picomolar concentrations of antibody. Moreover, the modular architecture of LUMABS allows changing of target specificity by simple exchange of epitope sequences, as demonstrated here for antibodies against HIV1-p17, hemagglutinin (HA), and dengue virus type I. The combination of sensitive ratiometric bioluminescent detection and the intrinsic modularity of the LUMABS design provides an attractive generic platform for point-of-care antibody detection that avoids the complex liquid handling steps associated with conventional immunoassays. PMID:27018236

  18. Molecular phylogeny and node time estimation of bioluminescent Lantern Sharks (Elasmobranchii: Etmopteridae).

    Science.gov (United States)

    Straube, Nicolas; Iglésias, Samuel P; Sellos, Daniel Y; Kriwet, Jürgen; Schliewen, Ulrich K

    2010-09-01

    Deep-sea Lantern Sharks (Etmopteridae) represent the most speciose family within Dogfish Sharks (Squaliformes). We compiled an extensive DNA dataset to estimate the first molecular phylogeny of the family and to provide node age estimates for the origin and diversification for this enigmatic group. Phylogenetic inferences yielded consistent and well supported hypotheses based on 4685bp of both nuclear (RAG1) and mitochondrial genes (COI, 12S-partial 16S, tRNAVal and tRNAPhe). The monophyletic family Etmopteridae originated in the early Paleocene around the C/T boundary, and split further into four morphologically distinct lineages supporting three of the four extant genera. The exception is Etmopterus which is paraphyletic with respect to Miroscyllium. Subsequent rapid radiation within Etmopterus in the Oligocene/early Miocene was accompanied by divergent evolution of bioluminescent flank markings which morphologically characterize the four lineages. Higher squaliform interrelationships could not be satisfactorily identified, but convergent evolution of bioluminescence in Dalatiidae and Etmopteridae is supported.

  19. Shedding light on microbial predator-prey population dynamics using a quantitative bioluminescence assay.

    Science.gov (United States)

    Im, Hansol; Kim, Dasol; Ghim, Cheol-Min; Mitchell, Robert J

    2014-01-01

    This study assessed the dynamics of predation by Bdellovibrio bacteriovorus HD 100. Predation tests with two different bioluminescent strains of Escherichia coli, one expressing a heat-labile bacterial luciferase and the other a heat-stable form, showed near identical losses from both, indicating that protein expression and stability are not responsible for the "shutting-off" of the prey bioluminescence (BL). Furthermore, it was found that the loss in the prey BL was not proportional with the predator-to-prey ratio (PPR), with significantly greater losses seen as this value was increased. This suggests that other factors also play a role in lowering the prey BL. The loss in BL, however, was very consistent within nine independent experiments to the point that we were able to reliably estimate the predator numbers within only 1 h when present at a PPR of 6 or higher, Using a fluorescent prey, we found that premature lysis of the prey occurs at a significant level and was more prominent as the PPR ratio increased. Based upon the supernatant fluorescent signal, even a relatively low PPR of 10-20 led to approximately 5% of the prey population being prematurely lysed within 1 h, while a PPR of 90 led to nearly 15% lysis. Consequently, we developed a modified Lotka-Volterra predator-prey model that accounted for this lysis and is able to reliably estimate the prey and bdelloplast populations for a wide range of PPRs. PMID:24272279

  20. In vivo bioluminescence imaging of Ca signalling in the brain of Drosophila.

    Directory of Open Access Journals (Sweden)

    Jean-René Martin

    Full Text Available Many different cells' signalling pathways are universally regulated by Ca(2+ concentration [Ca(2+] rises that have highly variable amplitudes and kinetic properties. Optical imaging can provide the means to characterise both the temporal and spatial aspects of Ca(2+ signals involved in neurophysiological functions. New methods for in vivo imaging of Ca(2+ signalling in the brain of Drosophila are required for probing the different dynamic aspects of this system. In studies here, whole brain Ca(2+ imaging was performed on transgenic flies with targeted expression of the bioluminescent Ca(2+ reporter GFP-aequorin (GA in different neural structures. A photon counting based technique was used to undertake continuous recordings of cytosolic [Ca(2+] over hours. Time integrals for reconstructing images and analysis of the data were selected offline according to the signal intensity. This approach allowed a unique Ca(2+ response associated with cholinergic transmission to be identified by whole brain imaging of specific neural structures. Notably, [Ca(2+] transients in the Mushroom Bodies (MBs following nicotine stimulation were accompanied by a delayed secondary [Ca(2+] rise (up to 15 min. later in the MB lobes. The delayed response was sensitive to thapsigargin, suggesting a role for intra-cellular Ca(2+ stores. Moreover, it was reduced in dunce mutant flies, which are impaired in learning and memory. Bioluminescence imaging is therefore useful for studying Ca(2+ signalling pathways and for functional mapping of neurophysiological processes in the fly brain.

  1. In vivo bioluminescence imaging of Ca signalling in the brain of Drosophila.

    Science.gov (United States)

    Martin, Jean-René; Rogers, Kelly L; Chagneau, Carine; Brûlet, Philippe

    2007-03-07

    Many different cells' signalling pathways are universally regulated by Ca(2+) concentration [Ca(2+)] rises that have highly variable amplitudes and kinetic properties. Optical imaging can provide the means to characterise both the temporal and spatial aspects of Ca(2+) signals involved in neurophysiological functions. New methods for in vivo imaging of Ca(2+) signalling in the brain of Drosophila are required for probing the different dynamic aspects of this system. In studies here, whole brain Ca(2+) imaging was performed on transgenic flies with targeted expression of the bioluminescent Ca(2+) reporter GFP-aequorin (GA) in different neural structures. A photon counting based technique was used to undertake continuous recordings of cytosolic [Ca(2+)] over hours. Time integrals for reconstructing images and analysis of the data were selected offline according to the signal intensity. This approach allowed a unique Ca(2+) response associated with cholinergic transmission to be identified by whole brain imaging of specific neural structures. Notably, [Ca(2+)] transients in the Mushroom Bodies (MBs) following nicotine stimulation were accompanied by a delayed secondary [Ca(2+)] rise (up to 15 min. later) in the MB lobes. The delayed response was sensitive to thapsigargin, suggesting a role for intra-cellular Ca(2+) stores. Moreover, it was reduced in dunce mutant flies, which are impaired in learning and memory. Bioluminescence imaging is therefore useful for studying Ca(2+) signalling pathways and for functional mapping of neurophysiological processes in the fly brain.

  2. In vivo Bioluminescence Imaging of Ca2+ Signalling in the Brain of Drosophila

    Science.gov (United States)

    Chagneau, Carine; Brûlet, Philippe

    2007-01-01

    Many different cells' signalling pathways are universally regulated by Ca2+ concentration [Ca2+] rises that have highly variable amplitudes and kinetic properties. Optical imaging can provide the means to characterise both the temporal and spatial aspects of Ca2+ signals involved in neurophysiological functions. New methods for in vivo imaging of Ca2+ signalling in the brain of Drosophila are required for probing the different dynamic aspects of this system. In studies here, whole brain Ca2+ imaging was performed on transgenic flies with targeted expression of the bioluminescent Ca2+ reporter GFP-aequorin (GA) in different neural structures. A photon counting based technique was used to undertake continuous recordings of cytosolic [Ca2+] over hours. Time integrals for reconstructing images and analysis of the data were selected offline according to the signal intensity. This approach allowed a unique Ca2+ response associated with cholinergic transmission to be identified by whole brain imaging of specific neural structures. Notably, [Ca2+] transients in the Mushroom Bodies (MBs) following nicotine stimulation were accompanied by a delayed secondary [Ca2+] rise (up to 15 min. later) in the MB lobes. The delayed response was sensitive to thapsigargin, suggesting a role for intra-cellular Ca2+ stores. Moreover, it was reduced in dunce mutant flies, which are impaired in learning and memory. Bioluminescence imaging is therefore useful for studying Ca2+ signalling pathways and for functional mapping of neurophysiological processes in the fly brain. PMID:17342209

  3. Quantification of bioluminescence images of point source objects using diffusion theory models

    International Nuclear Information System (INIS)

    A simple approach for estimating the location and power of a bioluminescent point source inside tissue is reported. The strategy consists of using a diffuse reflectance image at the emission wavelength to determine the optical properties of the tissue. Following this, bioluminescence images are modelled using a single point source and the optical properties from the reflectance image, and the depth and power are iteratively adjusted to find the best agreement with the experimental image. The forward models for light propagation are based on the diffusion approximation, with appropriate boundary conditions. The method was tested using Monte Carlo simulations, Intralipid tissue-simulating phantoms and ex vivo chicken muscle. Monte Carlo data showed that depth could be recovered within 6% for depth 4-12 mm, and the corresponding relative source power within 12%. In Intralipid, the depth could be estimated within 8% for depth 4-12 mm, and the relative source power, within 20%. For ex vivo tissue samples, source depths of 4.5 and 10 mm and their relative powers were correctly identified

  4. The cosmic ray muon tomography facility based on large scale MRPC detectors

    International Nuclear Information System (INIS)

    Cosmic ray muon tomography is a novel technology to detect high-Z material. A prototype of TUMUTY with 73.6 cm×73.6 cm large scale position sensitive MRPC detectors has been developed and is introduced in this paper. Three test kits have been tested and image is reconstructed using MAP algorithm. The reconstruction results show that the prototype is working well and the objects with complex structure and small size (20 mm) can be imaged on it, while the high-Z material is distinguishable from the low-Z one. This prototype provides a good platform for our further studies of the physical characteristics and the performances of cosmic ray muon tomography

  5. A plastic scintillator-based muon tomography system with an integrated muon spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Anghel, V. [Canadian Nuclear Laboratories Ltd (former Atomic Energy of Canada Ltd), Chalk River Laboratories, Chalk River, Canada K0J 1P0 (Canada); Armitage, J. [Department of Physics, Room 3302 Herzberg Laboratories, Carleton University, 1125 Colonel By Drive, Ottawa, Canada K1S 5B6 (Canada); Baig, F.; Boniface, K. [Canadian Nuclear Laboratories Ltd (former Atomic Energy of Canada Ltd), Chalk River Laboratories, Chalk River, Canada K0J 1P0 (Canada); Boudjemline, K. [Department of Physics, Room 3302 Herzberg Laboratories, Carleton University, 1125 Colonel By Drive, Ottawa, Canada K1S 5B6 (Canada); Bueno, J. [Advanced Applied Physics Solutions Inc., 4004 Wesbrook Mall, Vancouver, Canada V6T 2A3 (Canada); Charles, E. [Canada Border Services Agency, 79 Bentley Avenue, Ottawa, Canada K1A 0L8 (Canada); Drouin, P-L. [Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, Canada K1A 0Z4 (Canada); Erlandson, A., E-mail: Andrew.Erlandson@cnl.ca [Department of Physics, Room 3302 Herzberg Laboratories, Carleton University, 1125 Colonel By Drive, Ottawa, Canada K1S 5B6 (Canada); Canadian Nuclear Laboratories Ltd (former Atomic Energy of Canada Ltd), Chalk River Laboratories, Chalk River, Canada K0J 1P0 (Canada); Gallant, G. [Canada Border Services Agency, 79 Bentley Avenue, Ottawa, Canada K1A 0L8 (Canada); Gazit, R. [Advanced Applied Physics Solutions Inc., 4004 Wesbrook Mall, Vancouver, Canada V6T 2A3 (Canada); Godin, D.; Golovko, V.V. [Canadian Nuclear Laboratories Ltd (former Atomic Energy of Canada Ltd), Chalk River Laboratories, Chalk River, Canada K0J 1P0 (Canada); Howard, C. [Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, Canada K1A 0Z4 (Canada); Hydomako, R. [Advanced Applied Physics Solutions Inc., 4004 Wesbrook Mall, Vancouver, Canada V6T 2A3 (Canada); Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, Canada K1A 0Z4 (Canada); and others

    2015-10-21

    A muon scattering tomography system which uses extruded plastic scintillator bars for muon tracking and a dedicated muon spectrometer that measures scattering through steel slabs has been constructed and successfully tested. The atmospheric muon detection efficiency is measured to be 97% per plane on average and the average intrinsic hit resolution is 2.5 mm. In addition to creating a variety of three-dimensional images of objects of interest, a quantitative study has been carried out to investigate the impact of including muon momentum measurements when attempting to detect high-density, high-Z material. As expected, the addition of momentum information improves the performance of the system. For a fixed data-taking time of 60 s and a fixed false positive fraction, the probability to detect a target increases when momentum information is used. This is the first demonstration of the use of muon momentum information from dedicated spectrometer measurements in muon scattering tomography.

  6. Bioluminescence in the Ocean: Origins of Biological, Chemical, and Ecological Diversity

    Science.gov (United States)

    Widder, E. A.

    2010-05-01

    From bacteria to fish, a remarkable variety of marine life depends on bioluminescence (the chemical generation of light) for finding food, attracting mates, and evading predators. Disparate biochemical systems and diverse phylogenetic distribution patterns of light-emitting organisms highlight the ecological benefits of bioluminescence, with biochemical and genetic analyses providing new insights into the mechanisms of its evolution. The origins and functions of some bioluminescent systems, however, remain obscure. Here, I review recent advances in understanding bioluminescence in the ocean and highlight future research efforts that will unite molecular details with ecological and evolutionary relationships.

  7. Neural networks based neutron emissivity tomography at JET with real-time capabilities

    International Nuclear Information System (INIS)

    Tomographic reconstruction techniques typically require computationally intensive algorithms which are not suitable for real-time application. This paper describes a framework to perform neutron emissivity tomography at the Joint European Torus (JET) using neural networks with successful results over a broad range of magnetic configurations, heating and fueling schemes. Application times in the μs time scale allows for real-time applicability of the method.

  8. Neural networks based neutron emissivity tomography at JET with real-time capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Ronchi, E., E-mail: emanuele.ronchi@tsl.uu.s [JET-EFDA, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Association EURATOM-VR, Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala (Sweden); Conroy, S.; Andersson Sunden, E.; Ericsson, G.; Gatu Johnson, M.; Hellesen, C.; Sjoestrand, H.; Weiszflog, M. [JET-EFDA, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Association EURATOM-VR, Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala (Sweden)

    2010-02-01

    Tomographic reconstruction techniques typically require computationally intensive algorithms which are not suitable for real-time application. This paper describes a framework to perform neutron emissivity tomography at the Joint European Torus (JET) using neural networks with successful results over a broad range of magnetic configurations, heating and fueling schemes. Application times in the mus time scale allows for real-time applicability of the method.

  9. Principal-component-analysis-based estimation of blood flow velocities using optical coherence tomography intensity signals

    OpenAIRE

    Mohan, Nishant; Vakoc, Benjamin

    2011-01-01

    The intensity signal in optical coherence tomography contains information about the translational velocity of scatterers, and can be used to quantify blood flow. We apply principal component analysis to efficiently extract this information. We also study use of nonuniform temporal sampling of the intensity signal to increase the range of quantifiable flow velocities. We demonstrate this technique in simulation, phantom and in vivo blood flow measurements, and highlight its potential to enable...

  10. Detection of a bioluminescent milky sea from space

    OpenAIRE

    Miller, Steven D.; Haddock, Steven H. D.; Elvidge, Christopher D.; Thomas F. Lee

    2005-01-01

    On many occasions over the centuries, mariners have reported witnessing surreal nocturnal displays where the surface of the sea produces an intense, uniform, and sustained glow that extends to the horizon in all directions. Although such emissions cannot be fully reconciled with the known features of any light-emitting organism, these so-called “milky seas” are hypothesized to be manifestations of unusually strong bioluminescence produced by colonies of bacteria in association with a microalg...

  11. Bacterial bioluminescence and Gumbel statistics: From quorum sensing to correlation

    Science.gov (United States)

    Delle Side, Domenico; Velardi, Luciano; Nassisi, Vincenzo; Pennetta, Cecilia; Alifano, Pietro; Talà, Adelfia; Salvatore Tredici, Maurizio

    2013-12-01

    We show that, in particular experimental conditions, the time course of the radiant fluxes, measured from a bioluminescent emission of a Vibrio harveyi related strain, collapse after suitable rescaling onto the Gumbel distribution of extreme value theory. We argue that the activation times of the strain luminous emission follow the universal behavior described by this statistical law, in spite of the fact that no extremal process is known to occur.

  12. Bioluminescence in vivo imaging of autoimmune encephalomyelitis predicts disease

    OpenAIRE

    Steinman Lawrence; Ho Peggy; Luo Jian; Wyss-Coray Tony

    2008-01-01

    Abstract Background Experimental autoimmune encephalomyelitis is a widely used animal model to understand not only multiple sclerosis but also basic principles of immunity. The disease is scored typically by observing signs of paralysis, which do not always correspond with pathological changes. Methods Experimental autoimmune encephalomyelitis was induced in transgenic mice expressing an injury responsive luciferase reporter in astrocytes (GFAP-luc). Bioluminescence in the brain and spinal co...

  13. Bioluminescence for USP sterility testing of pharmaceutical suspension products.

    OpenAIRE

    Bussey, D M; K. Tsuji

    1986-01-01

    Bioluminescence measurement significantly improved the accuracy, sensitivity, precision, and reliability of the current visual endpoint determination for the USP sterility test and eliminated the day 7 transfer/dilution step required for testing suspension products. Thirteen strains of bacteria and fungi (representing potential contaminants in sterile products), three pharmaceutical suspension products, and four media were used in the experiment. No interference from suspension products was e...

  14. Bioluminescence imaging of estrogen receptor activity during breast cancer progression.

    Science.gov (United States)

    Vantaggiato, Cristina; Dell'Omo, Giulia; Ramachandran, Balaji; Manni, Isabella; Radaelli, Enrico; Scanziani, Eugenio; Piaggio, Giulia; Maggi, Adriana; Ciana, Paolo

    2016-01-01

    Estrogen receptors (ER) are known to play an important regulatory role in mammary gland development as well as in its neoplastic transformation. Although several studies highlighted the contribution of ER signaling in the breast transformation, little is known about the dynamics of ER state of activity during carcinogenesis due to the lack of appropriate models for measuring the extent of receptor signaling in time, in the same animal. To this aim, we have developed a reporter mouse model for the non-invasive in vivo imaging of ER activity: the ERE-Luc reporter mouse. ERE-Luc is a transgenic mouse generated with a firefly luciferase (Luc) reporter gene driven by a minimal promoter containing an estrogen responsive element (ERE). This model allows to measure receptor signaling in longitudinal studies by bioluminescence imaging (BLI). Here, we have induced sporadic mammary cancers by treating systemically ERE-Luc reporter mice with DMBA (9,10-dimethyl 1,2-benzanthracene) and measured receptor signaling by in vivo imaging in individual animals from early stage until a clinically palpable tumor appeared in the mouse breast. We showed that DMBA administration induces an increase of bioluminescence in the whole abdominal area 6 h after treatment, the signal rapidly disappears. Several weeks later, strong bioluminescence is observed in the area corresponding to the mammary glands. In vivo and ex vivo imaging analysis demonstrated that this bioluminescent signal is localized in the breast area undergoing neoplastic transformation. We conclude that this non-invasive assay is a novel relevant tool to identify the activation of the ER signaling prior the morphological detection of the neoplastic transformation.

  15. Proton radiography and proton computed tomography based on time-resolved dose measurements.

    Science.gov (United States)

    Testa, Mauro; Verburg, Joost M; Rose, Mark; Min, Chul Hee; Tang, Shikui; Bentefour, El Hassane; Paganetti, Harald; Lu, Hsiao-Ming

    2013-11-21

    We present a proof of principle study of proton radiography and proton computed tomography (pCT) based on time-resolved dose measurements. We used a prototype, two-dimensional, diode-array detector capable of fast dose rate measurements, to acquire proton radiographic images expressed directly in water equivalent path length (WEPL). The technique is based on the time dependence of the dose distribution delivered by a proton beam traversing a range modulator wheel in passive scattering proton therapy systems. The dose rate produced in the medium by such a system is periodic and has a unique pattern in time at each point along the beam path and thus encodes the WEPL. By measuring the time dose pattern at the point of interest, the WEPL to this point can be decoded. If one measures the time–dose patterns at points on a plane behind the patient for a beam with sufficient energy to penetrate the patient, the obtained 2D distribution of the WEPL forms an image. The technique requires only a 2D dosimeter array and it uses only the clinical beam for a fraction of second with negligible dose to patient. We first evaluated the accuracy of the technique in determining the WEPL for static phantoms aiming at beam range verification of the brain fields of medulloblastoma patients. Accurate beam ranges for these fields can significantly reduce the dose to the cranial skin of the patient and thus the risk of permanent alopecia. Second, we investigated the potential features of the technique for real-time imaging of a moving phantom. Real-time tumor tracking by proton radiography could provide more accurate validations of tumor motion models due to the more sensitive dependence of proton beam on tissue density compared to x-rays. Our radiographic technique is rapid (~100 ms) and simultaneous over the whole field, it can image mobile tumors without the problem of interplay effect inherently challenging for methods based on pencil beams. Third, we present the reconstructed p

  16. Nonrigid registration-based coronary artery motion correction for cardiac computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bhagalia, Roshni; Pack, Jed D.; Miller, James V.; Iatrou, Maria [GE Global Research, Niskayuna, New York 12309 (United States); GE Healthcare, Hoboken, New Jersey 07030 (United States)

    2012-07-15

    Purpose: X-ray computed tomography angiography (CTA) is the modality of choice to noninvasively monitor and diagnose heart disease with coronary artery health and stenosis detection being of particular interest. Reliable, clinically relevant coronary artery imaging mandates high spatiotemporal resolution. However, advances in intrinsic scanner spatial resolution (CT scanners are available which combine nearly 900 detector columns with focal spot oversampling) can be tempered by motion blurring, particularly in patients with unstable heartbeats. As a result, recently numerous methods have been devised to improve coronary CTA imaging. Solutions involving hardware, multisector algorithms, or {beta}-blockers are limited by cost, oversimplifying assumptions about cardiac motion, and populations showing contraindications to drugs, respectively. This work introduces an inexpensive algorithmic solution that retrospectively improves the temporal resolution of coronary CTA without significantly affecting spatial resolution. Methods: Given the goal of ruling out coronary stenosis, the method focuses on 'deblurring' the coronary arteries. The approach makes no assumptions about cardiac motion, can be used on exams acquired at high heart rates (even over 75 beats/min), and draws on a fast and accurate three-dimensional (3D) nonrigid bidirectional labeled point matching approach to estimate the trajectories of the coronary arteries during image acquisition. Motion compensation is achieved by employing a 3D warping of a series of partial reconstructions based on the estimated motion fields. Each of these partial reconstructions is created from data acquired over a short time interval. For brevity, the algorithm 'Subphasic Warp and Add' (SWA) reconstruction. Results: The performance of the new motion estimation-compensation approach was evaluated by a systematic observer study conducted using nine human cardiac CTA exams acquired over a range of average heart

  17. Proton radiography and proton computed tomography based on time-resolved dose measurements

    Science.gov (United States)

    Testa, Mauro; Verburg, Joost M.; Rose, Mark; Min, Chul Hee; Tang, Shikui; Hassane Bentefour, El; Paganetti, Harald; Lu, Hsiao-Ming

    2013-11-01

    We present a proof of principle study of proton radiography and proton computed tomography (pCT) based on time-resolved dose measurements. We used a prototype, two-dimensional, diode-array detector capable of fast dose rate measurements, to acquire proton radiographic images expressed directly in water equivalent path length (WEPL). The technique is based on the time dependence of the dose distribution delivered by a proton beam traversing a range modulator wheel in passive scattering proton therapy systems. The dose rate produced in the medium by such a system is periodic and has a unique pattern in time at each point along the beam path and thus encodes the WEPL. By measuring the time dose pattern at the point of interest, the WEPL to this point can be decoded. If one measures the time-dose patterns at points on a plane behind the patient for a beam with sufficient energy to penetrate the patient, the obtained 2D distribution of the WEPL forms an image. The technique requires only a 2D dosimeter array and it uses only the clinical beam for a fraction of second with negligible dose to patient. We first evaluated the accuracy of the technique in determining the WEPL for static phantoms aiming at beam range verification of the brain fields of medulloblastoma patients. Accurate beam ranges for these fields can significantly reduce the dose to the cranial skin of the patient and thus the risk of permanent alopecia. Second, we investigated the potential features of the technique for real-time imaging of a moving phantom. Real-time tumor tracking by proton radiography could provide more accurate validations of tumor motion models due to the more sensitive dependence of proton beam on tissue density compared to x-rays. Our radiographic technique is rapid (˜100 ms) and simultaneous over the whole field, it can image mobile tumors without the problem of interplay effect inherently challenging for methods based on pencil beams. Third, we present the reconstructed p

  18. Multifidus Muscle Volume Estimation Based on Three Dimensional Wavelet Multi Resolution Analysis: MRA with Buttocks Computer-Tomography: CT Images

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2013-12-01

    Full Text Available Multi-Resolution Analysis:. MRA based edge detection algorithm is proposed for estimation of volume of multifidus muscle in the Computer Tomography: CT scanned image The volume of multifidus muscle would be a good measure for metabolic syndrome rather than internal fat from a point of view from processing complexity. The proposed measure shows 0.178 of R square which corresponds to mutual correlation between internal fat and the volume of multifidus muscle. It is also fund that R square between internal fat and the other possible measures shows smaller than that of multifidus muscle.

  19. Improving depth resolution of diffuse optical tomography with an exponential adjustment method based on maximum singular value of layered sensitivity

    Institute of Scientific and Technical Information of China (English)

    Haijing Niu; Ping Guo; Xiaodong Song; Tianzi Jiang

    2008-01-01

    The sensitivity of diffuse optical tomography (DOT) imaging exponentially decreases with the increase of photon penetration depth, which leads to a poor depth resolution for DOT. In this letter, an exponential adjustment method (EAM) based on maximum singular value of layered sensitivity is proposed. Optimal depth resolution can be achieved by compensating the reduced sensitivity in the deep medium. Simulations are performed using a semi-infinite model and the simulation results show that the EAM method can substantially improve the depth resolution of deeply embedded objects in the medium. Consequently, the image quality and the reconstruction accuracy for these objects have been largely improved.

  20. Probability-based non-local means filter for speckle noise suppression in optical coherence tomography images.

    Science.gov (United States)

    Yu, Hancheng; Gao, Jianlin; Li, Aiting

    2016-03-01

    In this Letter, a probability-based non-local means filter is proposed for speckle reduction in optical coherence tomography (OCT). Originally developed for additive white Gaussian noise, the non-local means filter is not suitable for multiplicative speckle noise suppression. This Letter presents a two-stage non-local means algorithm using the uncorrupted probability of each pixel to effectively reduce speckle noise in OCT. Experiments on real OCT images demonstrate that the proposed filter is competitive with other state-of-the-art speckle removal techniques and able to accurately preserve edges and structural details with small computational cost. PMID:26974099

  1. High-speed polarization sensitive optical coherence tomography scan engine based on Fourier domain mode locked laser

    OpenAIRE

    Bonesi, Marco; Sattmann, Harald; Torzicky, Teresa; Zotter, Stefan; Baumann, Bernhard; Pircher, Michael; Götzinger, Erich; Eigenwillig, Christoph; Wieser, Wolfgang; Huber, Robert; Hitzenberger, Christoph K.

    2012-01-01

    We report on a new swept source polarization sensitive optical coherence tomography scan engine that is based on polarization maintaining (PM) fiber technology. The light source is a Fourier domain mode locked laser with a PM cavity that operates in the 1300 nm wavelength regime. It is equipped with a PM buffer stage that doubles the fundamental sweep frequency of 54.5 kHz. The fiberization allows coupling of the scan engine to different delivery probes. In a first demonstration, we use the s...

  2. A geometricla error in some Computer Programs based on the Aki-Christofferson-Husebye (ACH) Method of Teleseismic Tomography

    Science.gov (United States)

    Julian, B.R.; Evans, J.R.; Pritchard, M.J.; Foulger, G.R.

    2000-01-01

    Some computer programs based on the Aki-Christofferson-Husebye (ACH) method of teleseismic tomography contain an error caused by identifying local grid directions with azimuths on the spherical Earth. This error, which is most severe in high latitudes, introduces systematic errors into computed ray paths and distorts inferred Earth models. It is best dealt with by explicity correcting for the difference between true and grid directions. Methods for computing these directions are presented in this article and are likely to be useful in many other kinds of regional geophysical studies that use Cartesian coordinates and flat-earth approximations.

  3. In vivo bioluminescence and reflectance imaging of multiple organs in bioluminescence reporter mice by bundled-fiber-coupled microscopy

    Science.gov (United States)

    Ando, Yoriko; Sakurai, Takashi; Koida, Kowa; Tei, Hajime; Hida, Akiko; Nakao, Kazuki; Natsume, Mistuo; Numano, Rika

    2016-01-01

    Bioluminescence imaging (BLI) is used in biomedical research to monitor biological processes within living organisms. Recently, fiber bundles with high transmittance and density have been developed to detect low light with high resolution. Therefore, we have developed a bundled-fiber-coupled microscope with a highly sensitive cooled-CCD camera that enables the BLI of organs within the mouse body. This is the first report of in vivo BLI of the brain and multiple organs in luciferase-reporter mice using bundled-fiber optics. With reflectance imaging, the structures of blood vessels and organs can be seen clearly with light illumination, and it allowed identification of the structural details of bioluminescence images. This technique can also be applied to clinical diagnostics in a low invasive manner. PMID:27231601

  4. In vivo bioluminescence and reflectance imaging of multiple organs in bioluminescence reporter mice by bundled-fiber-coupled microscopy.

    Science.gov (United States)

    Ando, Yoriko; Sakurai, Takashi; Koida, Kowa; Tei, Hajime; Hida, Akiko; Nakao, Kazuki; Natsume, Mistuo; Numano, Rika

    2016-03-01

    Bioluminescence imaging (BLI) is used in biomedical research to monitor biological processes within living organisms. Recently, fiber bundles with high transmittance and density have been developed to detect low light with high resolution. Therefore, we have developed a bundled-fiber-coupled microscope with a highly sensitive cooled-CCD camera that enables the BLI of organs within the mouse body. This is the first report of in vivo BLI of the brain and multiple organs in luciferase-reporter mice using bundled-fiber optics. With reflectance imaging, the structures of blood vessels and organs can be seen clearly with light illumination, and it allowed identification of the structural details of bioluminescence images. This technique can also be applied to clinical diagnostics in a low invasive manner.

  5. Advancement of Compositional and Microstructural Design of Intermetallic γ-TiAl Based Alloys Determined by Atom Probe Tomography

    Directory of Open Access Journals (Sweden)

    Thomas Klein

    2016-09-01

    Full Text Available Advanced intermetallic alloys based on the γ-TiAl phase have become widely regarded as most promising candidates to replace heavier Ni-base superalloys as materials for high-temperature structural components, due to their facilitating properties of high creep and oxidation resistance in combination with a low density. Particularly, recently developed alloying concepts based on a β-solidification pathway, such as the so-called TNM alloy, which are already incorporated in aircraft engines, have emerged offering the advantage of being processible using near-conventional methods and the option to attain balanced mechanical properties via subsequent heat-treatment. Development trends for the improvement of alloying concepts, especially dealing with issues regarding alloying element distribution, nano-scale phase characterization, phase stability, and phase formation mechanisms demand the utilization of high-resolution techniques, mainly due to the multi-phase nature of advanced TiAl alloys. Atom probe tomography (APT offers unique possibilities of characterizing chemical compositions with a high spatial resolution and has, therefore, been widely used in recent years with the aim of understanding the materials constitution and appearing basic phenomena on the atomic scale and applying these findings to alloy development. This review, thus, aims at summarizing scientific works regarding the application of atom probe tomography towards the understanding and further development of intermetallic TiAl alloys.

  6. Hardware and software design for a National Instrument-based magnetic induction tomography system for prospective biomedical applications

    International Nuclear Information System (INIS)

    Magnetic induction tomography (MIT) is a new and emerging type of tomography technique that is able to map the passive electromagnetic properties (in particular conductivity) of an object. Excitation coils are used to induce eddy currents in the medium, and the magnetic field produced by the induced eddy current is then sensed by the receiver coils. Because of its non-invasive and contactless feature, it becomes an attractive technique for many applications (especially in biomedical area) compared to traditional contact electrode-based electrical impedance tomography. Due to the low contrast in conductivity between biological tissues, an accurate and stable hardware system is necessary. Most MIT systems in the literature employ external signal generators, power amplifiers and highly stable down-conversion electronics to obtain a satisfactory phase measurement. However, this would increase design complexity substantially. In this paper, a National Instrument-based MIT system is developed at the University of Bath, aiming for biomedical applications. The system utilizes National Instrument products to accomplish all signal driving, switching and data acquisition tasks, which ease the system design whilst providing satisfactory performance. This paper presents a full-scaled medical MIT system, from the sensor and system hardware design, eddy current model verification to the image reconstruction software: the performance of this MIT instrumentation system is characterized in detail, including the system accuracy and system stability. The methods of solving eddy current problem are presented. The reconstructed images of detecting the presence of saline solutions are also included in this paper, which show the capability of national instrument products to be developed into a full-scaled biomedical MIT system, by demonstrating the practical experimental results. (paper)

  7. Synchronization of circadian bioluminescence as a group-foraging strategy in cave glowworms.

    Science.gov (United States)

    Maynard, Andrew J; Merritt, David J

    2013-07-01

    Flies of the genus Arachnocampa are sit-and-lure predators that use bioluminescence to attract flying prey to their silk webs. Some species are most common in rainforest habitat and others inhabit both caves and rainforest. We have studied the circadian regulation of bioluminescence in two species: one found in subtropical rainforest with no known cave populations and the other found in temperate rainforest with large populations in limestone caves. The rainforest species is typical of most nocturnal animals in that individuals are entrained by the light:dark (LD) cycle to be active at night; in this case, their propensity to bioluminesce is greatest at night. The dual-habitat species shows an opposite phase response to the same entrainment; its bioluminescence propensity rhythm is entrained by LD exposure to peak during the day. Nevertheless, in LD environments, individuals do not bioluminesce during the day because ambient light inhibits their bioluminescence (negative masking), pushing bioluminescence into the dark period. This unusual and unexpected phenomenon could be related to their association with caves and has been suggested to be an adaptation of the circadian system that promotes synchronization of a colony's output of bioluminescence. Here, we use controlled laboratory experiments to show that individuals do synchronize their bioluminescence rhythms when in visual contact with each other. Entrainment of the bioluminescence rhythm to the biological photophase causes colony-wide synchronization, creating a daily sinusoidal rhythm of the intensity of bioluminescence in the many thousands of individuals making up a colony. This synchronization could provide a group-foraging advantage, allowing the colony to glow most brightly when the prey are most likely to be active. PMID:23575257

  8. Synchronization of circadian bioluminescence as a group-foraging strategy in cave glowworms.

    Science.gov (United States)

    Maynard, Andrew J; Merritt, David J

    2013-07-01

    Flies of the genus Arachnocampa are sit-and-lure predators that use bioluminescence to attract flying prey to their silk webs. Some species are most common in rainforest habitat and others inhabit both caves and rainforest. We have studied the circadian regulation of bioluminescence in two species: one found in subtropical rainforest with no known cave populations and the other found in temperate rainforest with large populations in limestone caves. The rainforest species is typical of most nocturnal animals in that individuals are entrained by the light:dark (LD) cycle to be active at night; in this case, their propensity to bioluminesce is greatest at night. The dual-habitat species shows an opposite phase response to the same entrainment; its bioluminescence propensity rhythm is entrained by LD exposure to peak during the day. Nevertheless, in LD environments, individuals do not bioluminesce during the day because ambient light inhibits their bioluminescence (negative masking), pushing bioluminescence into the dark period. This unusual and unexpected phenomenon could be related to their association with caves and has been suggested to be an adaptation of the circadian system that promotes synchronization of a colony's output of bioluminescence. Here, we use controlled laboratory experiments to show that individuals do synchronize their bioluminescence rhythms when in visual contact with each other. Entrainment of the bioluminescence rhythm to the biological photophase causes colony-wide synchronization, creating a daily sinusoidal rhythm of the intensity of bioluminescence in the many thousands of individuals making up a colony. This synchronization could provide a group-foraging advantage, allowing the colony to glow most brightly when the prey are most likely to be active.

  9. la bioluminescence de l'aequorine en réponse au calcium In vitro et dans le Cortex cerebral

    OpenAIRE

    Tricoire, Ludovic

    2006-01-01

    During my PhD, I investigated in vitro the calcium-dependent bioluminescence of thephotoprotein aequorin and then used its bioluminescence to image neuronal activities in theneocortical network. This genetically encoded calcium sensor can be expressed in specific cell types and its bioluminescence is not toxic and exhibit a high signal/noise ratio.I first search for mutations modifying aequorin bioluminescence, using a randommutagenesis and in vitro evolution approach. I isolated mutants show...

  10. Singular value decomposition-based reconstruction algorithm for seismic traveltime tomography.

    Science.gov (United States)

    Song, L P; Zhang, S Y

    1999-01-01

    A reconstruction method is given for seismic transmission traveltime tomography. The method is implemented via the combinations of singular value decomposition, appropriate weighting matrices, and variable regularization parameter. The problem is scaled through the weighting matrices so that the singular spectrum is normalized. Matching the normalized singular values, a regularization parameter varies within the interval [0, 1], and linearly increases with singular value index from a small, initial value rather than a fixed one to eliminate the impacts of smaller singular values' components. The experimental results show that the proposed method is superior to the ordinary singular value decomposition (SVD) methods such as truncated SVD and Tikhonov regularization. PMID:18267533

  11. GPS-based ionospheric tomography with a constrained adaptive simultaneous algebraic reconstruction technique

    Indian Academy of Sciences (India)

    Wen Debao; Zhang Xiao; Tong Yangjin; Zhang Guangsheng; Zhang Min; Leng Rusong

    2015-03-01

    In this paper, a constrained adaptive simultaneous algebraic reconstruction technique (CASART) is presented to obtain high-quality reconstructions from insufficient projections. According to the continuous smoothness of the variations of ionospheric electron density (IED) among neighbouring voxels, Gauss weighted function is introduced to constrain the tomography system in the new method. It can resolve the dependence on the initial values for those voxels without any GPS rays traversing them. Numerical simulation scheme is devised to validate the feasibility of the new algorithm. Some comparisons are made to demonstrate the superiority of the new method. Finally, the actual GPS observations are applied to further validate the feasibility and superiority of the new algorithm.

  12. Polymer film-based optical access to enclosed gas: demonstration of H2O absorption tomography

    Science.gov (United States)

    Wang, Ze; Anderson, Mark H.; Sanders, Scott T.

    2016-09-01

    We demonstrate the use of a film to enable optical access to enclosed gases. We use absorption tomography to image H2O in a 101.6-mm-diameter duct with 2-mm spatial resolution. Considering the central 94 mm, the standard deviation of the image is 1.6 %, and the average mole fraction error is -0.008 %. A polybenzimidazole film is identified to be a candidate for extending the technique to enable NH3 imaging in a diesel aftertreatment system.

  13. Investigation of noise properties in grating-based x-ray phase tomography with reverse projection method

    Science.gov (United States)

    Bao, Yuan; Wang, Yan; Gao, Kun; Wang, Zhi-Li; Zhu, Pei-Ping; Wu, Zi-Yu

    2015-10-01

    The relationship between noise variance and spatial resolution in grating-based x-ray phase computed tomography (PCT) imaging is investigated with reverse projection extraction method, and the noise variances of the reconstructed absorption coefficient and refractive index decrement are compared. For the differential phase contrast method, the noise variance in the differential projection images follows the same inverse-square law with spatial resolution as in conventional absorption-based x-ray imaging projections. However, both theoretical analysis and simulations demonstrate that in PCT the noise variance of the reconstructed refractive index decrement scales with spatial resolution follows an inverse linear relationship at fixed slice thickness, while the noise variance of the reconstructed absorption coefficient conforms with the inverse cubic law. The results indicate that, for the same noise variance level, PCT imaging may enable higher spatial resolution than conventional absorption computed tomography (ACT), while ACT benefits more from degraded spatial resolution. This could be a useful guidance in imaging the inner structure of the sample in higher spatial resolution. Project supported by the National Basic Research Program of China (Grant No. 2012CB825800), the Science Fund for Creative Research Groups, the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant Nos. KJCX2-YW-N42 and Y4545320Y2), the National Natural Science Foundation of China (Grant Nos. 11475170, 11205157, 11305173, 11205189, 11375225, 11321503, 11179004, and U1332109).

  14. Investigation of noise properties in grating-based x-ray phase tomography with reverse projection method

    Institute of Scientific and Technical Information of China (English)

    鲍园; 王研; 高昆; 王志立; 朱佩平; 吴自玉

    2015-01-01

    The relationship between noise variance and spatial resolution in grating-based x-ray phase computed tomography (PCT) imaging is investigated with reverse projection extraction method, and the noise variances of the reconstructed absorption coefficient and refractive index decrement are compared. For the differential phase contrast method, the noise variance in the differential projection images follows the same inverse-square law with spatial resolution as in conventional absorption-based x-ray imaging projections. However, both theoretical analysis and simulations demonstrate that in PCT the noise variance of the reconstructed refractive index decrement scales with spatial resolution follows an inverse linear relationship at fixed slice thickness, while the noise variance of the reconstructed absorption coefficient conforms with the inverse cubic law. The results indicate that, for the same noise variance level, PCT imaging may enable higher spatial resolution than conventional absorption computed tomography (ACT), while ACT benefits more from degraded spatial resolution. This could be a useful guidance in imaging the inner structure of the sample in higher spatial resolution.

  15. Multiscale modeling of lithium-ion battery electrodes based on nano-scale X-ray computed tomography

    Science.gov (United States)

    Kashkooli, Ali Ghorbani; Farhad, Siamak; Lee, Dong Un; Feng, Kun; Litster, Shawn; Babu, Siddharth Komini; Zhu, Likun; Chen, Zhongwei

    2016-03-01

    A multiscale platform has been developed to model lithium ion battery (LIB) electrodes based on the real microstructure morphology. This multiscale framework consists of a microscale level where the electrode microstructure architecture is modeled and a macroscale level where discharge/charge is simulated. The coupling between two scales are performed in real time unlike using common surrogate based models for microscale. For microscale geometry 3D microstructure is reconstructed based on the nano-scale X-ray computed tomography data replacing typical computer generated microstructure. It is shown that this model can predict the experimental performance of LiFePO4 (LFP) cathode at different discharge rates more accurate than the conventional homogenous models. The approach employed in this study provides valuable insight into the spatial distribution of lithium -ion inside the real microstructure of LIB electrodes. The inhomogenous microstructure of LFP causes a wider range of physical and electrochemical properties in microscale compared to homogenous models.

  16. Technetium-99m sestamibi myocardial tomography based on dipyridamole echocardiography testing in hypertensive patients with chest pain

    Energy Technology Data Exchange (ETDEWEB)

    Schillaci, O. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy); Moroni, C. [Department of Internal Medicine, University ``La Sapienza``, Rome (Italy); Scopinaro, F. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy); Tavolaro, R. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy); Danieli, R. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy); Bossini, A. [Department of Internal Medicine, University ``La Sapienza``, Rome (Italy); Cassone, R. [Department of Internal Medicine, University ``La Sapienza``, Rome (Italy); Colella, A.C. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy)

    1997-07-01

    The aim of this study was to evaluate the diagnostic capability of technetium-99m sestamibi tomography based on dipyridamole echocardiography testing in hypertensives with chest pain, and to compare the scintigraphic results with those of coronary angiography, exercise electrocardiography and dipyridamole echocardiography. Forty subjects with mild to moderate hypertension, chest pain and no previous myocardial infarction were submitted to {sup 99m}Tc-sestamibi tomography (at rest and after high-dose dipyridamole echocardiography) and to exercise electrocardiography testing. At coronary angiography 22 patients (group A) had significant epicardial coronary artery disease ({>=}70% stenosis of at least one major vessel) and 18 normal main coronary vessels (group B). Dipyridamole {sup 99m}Tc-sestamibi imaging was positive in 21/22 patients of group A and in 5/18 of group B. Dipyridamole echocardiography was positive in 18/22 patients of group A and in 5/18 of group B. Exercise electrocardiography was positive in 15/22 patients of group A and in 11/18 of group B. Four out of five subjects in group B with positive results in all the tests showed a slow run-off of angiographic contrast medium, probably due to small-vessel disease. Significant epicardial coronary artery disease in hypertensives with chest pain is unlikely when dipyridamole {sup 99m}Tc-sestamibi tomography is negative. When scintigraphy is positive, either epicardial coronary artery disease or a small-vessel disease condition is possible. The association of scintigraphy with dipyridamole echocardiography testing allows the assessment of contractile function and myocardial perfusion by a single pharmacological stress. (orig./AJ). With 3 figs., 2 tabs.

  17. Technetium-99m sestamibi myocardial tomography based on dipyridamole echocardiography testing in hypertensive patients with chest pain

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the diagnostic capability of technetium-99m sestamibi tomography based on dipyridamole echocardiography testing in hypertensives with chest pain, and to compare the scintigraphic results with those of coronary angiography, exercise electrocardiography and dipyridamole echocardiography. Forty subjects with mild to moderate hypertension, chest pain and no previous myocardial infarction were submitted to 99mTc-sestamibi tomography (at rest and after high-dose dipyridamole echocardiography) and to exercise electrocardiography testing. At coronary angiography 22 patients (group A) had significant epicardial coronary artery disease (≥70% stenosis of at least one major vessel) and 18 normal main coronary vessels (group B). Dipyridamole 99mTc-sestamibi imaging was positive in 21/22 patients of group A and in 5/18 of group B. Dipyridamole echocardiography was positive in 18/22 patients of group A and in 5/18 of group B. Exercise electrocardiography was positive in 15/22 patients of group A and in 11/18 of group B. Four out of five subjects in group B with positive results in all the tests showed a slow run-off of angiographic contrast medium, probably due to small-vessel disease. Significant epicardial coronary artery disease in hypertensives with chest pain is unlikely when dipyridamole 99mTc-sestamibi tomography is negative. When scintigraphy is positive, either epicardial coronary artery disease or a small-vessel disease condition is possible. The association of scintigraphy with dipyridamole echocardiography testing allows the assessment of contractile function and myocardial perfusion by a single pharmacological stress. (orig./AJ). With 3 figs., 2 tabs

  18. A bent Laue-Laue monochromator for a synchrotron-based computed tomography system

    CERN Document Server

    Ren, B; Chapman, L D; Ivanov, I; Wu, X Y; Zhong, Z; Huang, X

    1999-01-01

    We designed and tested a two-crystal bent Laue-Laue monochromator for wide, fan-shaped synchrotron X-ray beams for the program multiple energy computed tomography (MECT) at the National Synchrotron Light Source (NSLS). MECT employs monochromatic X-ray beams from the NSLS's X17B superconducting wiggler beamline for computed tomography (CT) with an improved image quality. MECT uses a fixed horizontal fan-shaped beam with the subject's apparatus rotating around a vertical axis. The new monochromator uses two Czochralski-grown Si crystals, 0.7 and 1.4 mm thick, respectively, and with thick ribs on their upper and lower ends. The crystals are bent cylindrically, with the axis of the cylinder parallel to the fan beam, using 4-rod benders with two fixed rods and two movable ones. The bent-crystal feature of the monochromator resolved the difficulties we had had with the flat Laue-Laue design previously used in MECT, which included (a) inadequate beam intensity, (b) excessive fluctuations in beam intensity, and (c) i...

  19. Determination of myocardial ischemia and degree of reperfusion based on optical coherence tomography

    Institute of Scientific and Technical Information of China (English)

    Haiyu Chen; Guoxing Weng; Zhifang Li; Hui Li; Xiamei Cai

    2011-01-01

    @@ The feasibility of applying optical coherence tomography (OCT) in determining the degree of myocardial ischemia-reperfusion injury is assessed. The left anterior descending coronary artery of 90 Sprague-Dawley rats are ligated and reperfused at different times. The total attenuation coefficient obtained from the OCT images in the experimental group keeps increasing with reperfusion time and highly correlates with the histopathological characteristics (P<0.01). We present evidence proving the feasibility of using OCT for evaluating myocardial ischemia reperfusion.%The feasibility of applying optical coherence tomography (OCT) in determining the degree of myocardial ischemia-reperfusion injury is assessed. The left anterior descending coronary artery of 90 Sprague-Dawley rats are ligated and reperfused at different times. The total attenuation coefficient obtained from the OCT images in the experimental group keeps increasing with reperfusion time and highly correlates with the histopathological characteristics (P < 0.01). We present evidence proving the feasibility of using OCT for evaluating myocardial ischemia reperfusion.

  20. 23 kHz MEMS based swept source for optical coherence tomography imaging.

    Science.gov (United States)

    Vuong, Barry; Sun, Cuiru; Harduar, Mark K; Mariampillai, Adrian; Isamoto, Keiji; Chong, Changho; Standish, Beau A; Yang, Victor X D

    2011-01-01

    The transition from benchtop to clinical system often requires the medical technology to be robust, portable and accurate. This poses a challenge to current swept source optical coherence tomography imaging systems, as the bulk of the systems footprint is due to laser components. With the recent advancement of micromachining technology, we demonstrate the characterization of a microelectromechanical system (MEMS) swept source laser for optical coherence tomography imaging (OCT). This laser utilizes a 2 degree of freedom MEMS scanning mirror and a diffraction grating, which are arranged in a Littrow configuration. This resulted in a swept source laser that was capable of scanning at 23.165 kHz (bidirectional) or 11.582 kHz (unidirectional). The free spectral range of the laser was ≈ 100 nm with a central wavelength of ≈ 1330 nm. The 6 dB roll off depth was measured to be at 2.5 mm. Furthermore, the structural morphology of a human finger and tadpole (Xenopus laevis) were evaluated. The overall volumetric footprint of the laser source was measured to be 70 times less than non-MEMS swept sources. Continued work on the miniaturization of OCT system is on going. It is hypothesized that the overall laser size can be reduced for suitable OCT imaging for a point of care application. PMID:22255739