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Bioanalytical Applications of Real-Time ATP Imaging Via Bioluminescence  

Energy Technology Data Exchange (ETDEWEB)

The research discussed within involves the development of novel applications of real-time imaging of adenosine 5'-triphosphate (ATP). ATP was detected via bioluminescence and the firefly luciferase-catalyzed reaction of ATP and luciferin. The use of a microscope and an imaging detector allowed for spatially resolved quantitation of ATP release. Employing this method, applications in both biological and chemical systems were developed. First, the mechanism by which the compound 48/80 induces release of ATP from human umbilical vein endothelial cells (HUVECs) was investigated. Numerous enzyme activators and inhibitors were utilized to probe the second messenger systems involved in release. Compound 48/80 activated a G{sub q}-type protein to initiate ATP release from HUVECs. Ca{sup 2+} imaging along with ATP imaging revealed that activation of phospholipase C and induction of intracellular Ca{sup 2+} signaling were necessary for release of ATP. Furthermore, activation of protein kinase C inhibited the activity of phospholipase C and thus decreased the magnitude of ATP release. This novel release mechanism was compared to the existing theories of extracellular release of ATP. Bioluminescence imaging was also employed to examine the role of ATP in the field of neuroscience. The central nervous system (CNS) was dissected from the freshwater snail Lymnaea stagnalis. Electrophysiological experiments demonstrated that the neurons of the Lymnaea were not damaged by any of the components of the imaging solution. ATP was continuously released by the ganglia of the CNS for over eight hours and varied from ganglion to ganglion and within individual ganglia. Addition of the neurotransmitters K{sup +} and serotonin increased release of ATP in certain regions of the Lymnaea CNS. Finally, the ATP imaging technique was investigated for the study of drug release systems. MCM-41-type mesoporous nanospheres were loaded with ATP and end-capped with mercaptoethanol functionalized CdS monocrystals. Aggregates of nanospheres were bathed in imaging solution, and ATP bioluminescence was monitored to investigated the release kinetics of the nanosphere drug delivery systems. Addition of disulfide bond-cleaving molecules induced uncapping of the nanospheres and subsequently, the release of ATP. Increasing the concentration of the uncapping molecule decreased the temporal maximum and increased the magnitude of release of encapsulated ATP from the nanospheres. Furthermore, the release kinetics from the nanospheres varied with the size of the particle aggregates.

Jason Alan Gruenhagen

2003-12-12

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Real-time in vivo bioluminescence imaging of lentiviral vector-mediated gene transfer in mouse testis.  

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Although much research has focused on transferring exogenous genes into living mouse testis to investigate specific gene functions in spermatogenic, Sertoli, and Leydig cells, relatively little is known regarding real-time gene expression in vivo. In this study, we constructed a bicistronic lentiviral vector (LV) encoding firefly luciferase and enhanced green fluorescence protein (EGFP); this was a highly efficient in vivo gene transfer tool. After microinjecting LV into the seminiferous tubules the ICR mouse testis, we detected luciferase and EGFP expression in vivo and ex vivo in the injected tubules using bioluminescence imaging (BLI) with the IVIS-200 system and fibered confocal fluorescence microscopy (CellViZio), respectively. In addition, with an in vivo BLI system, luciferase expression in the testis was detected for approximately 3 mo. Furthermore, EGFP expression in seminiferous tubules was confirmed in excised testes via three-dimensional fluorescent imaging with a confocal laser-scanning microscope. With immunostaining, EGFP expression was confirmed in several male germ cell types in the seminiferous tubules, as well as in Sertoli and Leydig cells. In conclusion, we demonstrated that real-time in vivo BLI analysis can be used to noninvasively (in vivo) monitor long-term luciferase expression in mouse testis, and we verified that EGFP expression is localized in seminiferous tubules after bicistronic LV-mediated gene transfer into mouse testes. Furthermore, we anticipate the future use of in vivo BLI technology for real-time study of specific genes involved in spermatogenesis. PMID:19837451

Kim, T S; Choi, H S; Ryu, B Y; Gang, G T; Kim, S U; Koo, D B; Kim, J M; Han, J H; Park, C K; Her, S; Lee, D S

2010-01-01

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Bioluminescence in vivo imaging of autoimmune encephalomyelitis predicts disease  

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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.

Steinman Lawrence

2008-02-01

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Continuous, real-time bioimaging of chemical bioavailability and toxicology using autonomously bioluminescent human cell lines  

Science.gov (United States)

Bioluminescent imaging is an emerging biomedical surveillance strategy that uses external cameras to detect in vivo light generated in small animal models of human physiology or in vitro light generated in tissue culture or tissue scaffold mimics of human anatomy. The most widely utilized of reporters is the firefly luciferase (luc) gene; however, it generates light only upon addition of a chemical substrate, thus only generating intermittent single time point data snapshots. To overcome this disadvantage, we have demonstrated substrate-independent bioluminescent imaging using an optimized bacterial bioluminescence (lux) system. The lux reporter produces bioluminescence autonomously using components found naturally within the cell, thereby allowing imaging to occur continuously and in real-time over the lifetime of the host. We have validated this technology in human cells with demonstrated chemical toxicological profiling against exotoxin exposures at signal strengths comparable to existing luc systems (~1.33 × 107 photons/second). As a proof-in-principle demonstration, we have engineered breast carcinoma cells to express bioluminescence for real-time screening of endocrine disrupting chemicals and validated detection of 17?-estradiol (EC50 = ~ 10 pM). These and other applications of this new reporter technology will be discussed as potential new pathways towards improved models of target chemical bioavailability, toxicology, efficacy, and human safety.

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

2013-05-01

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Computer-aided photometric analysis of dynamic digital bioluminescent images  

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The paper deals with photometric and morphologic analysis of bioluminescent images obtained by registration of light radiated directly from some plant objects. Registration of images obtained from ultra-weak light sources by the single photon counting (SPC) technique is the subject of this work. The radiation is registered by use of a 16-bit charge coupled device (CCD) camera "Night Owl" together with WinLight EG&G Berthold software. Additional application-specific software has been developed in order to deal with objects that are changing during the exposition time. Advantages of the elaborated set of easy configurable tools named FCT for a computer-aided photometric and morphologic analysis of numerous series of quantitatively imperfect chemiluminescent images are described. Instructions are given how to use these tools and exemplified with several algorithms for the transformation of images library. Using the proposed FCT set, automatic photometric and morphologic analysis of the information hidden within series of chemiluminescent images reflecting defensive processes in poinsettia (Euphorbia pulcherrima Willd) leaves affected by a pathogenic fungus Botrytis cinerea is revealed.

Gorski, Zbigniew; Bembnista, T.; Floryszak-Wieczorek, J.; Domanski, Marek; Slawinski, Janusz

2003-04-01

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Modeling and image reconstruction in spectrally resolved bioluminescence tomography  

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Recent interest in modeling and reconstruction algorithms for Bioluminescence Tomography (BLT) has increased and led to the general consensus that non-spectrally resolved intensity-based BLT results in a non-unique problem. However, the light emitted from, for example firefly Luciferase, is widely distributed over the band of wavelengths from 500 nm to 650 nm and above, with the dominant fraction emitted from tissue being above 550 nm. This paper demonstrates the development of an algorithm used for multi-wavelength 3D spectrally resolved BLT image reconstruction in a mouse model. It is shown that using a single view data, bioluminescence sources of up to 15 mm deep can be successfully recovered given correct information about the underlying tissue absorption and scatter.

Dehghani, Hamid; Pogue, Brian W.; Davis, Scott C.; Patterson, Michael S.

2007-02-01

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Development of lung tissue phantoms for bioluminescent imaging  

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White nylon material was chosen to make cylindrical tissue phantoms for development of bioluminescence tomography techniques. A low-level light source, delivered through a optic fiber of core diameter 200mm, was placed at different locations on one phantom surface. The light travels through the phantom, reaches the external surface, and is captured by a liquid nitrogen-cooled CCD camera. The scattering, absorption, and anisotropy parameters of the phantom are obtained by matching the measured light transmission profiles to the profiles generated by the TracePro software. The perturbation analysis, with the homogeneous phantoms, demonstrated that the imaging system is sufficiently sensitive to capture intensity change of higher than 0.5nW/cm2 or a location shift of the light source of more than 200microns. It is observed that the system can distinguish two point light sources with separation of about 2mm. The perturbation analysis is also performed with the heterogeneous phantom. Based on our data, we conclude that there is inherent tomographic information in bioluminescent measures taken on the external surface of the mouse, which suggests the feasibility of bioluminescence tomography for biomedical research using the small animals, especially the mice.

Kumar, Durairaj; Cong, Wenxiang; Bohenkamp, Frank; Kakaday, Tarun; Taft, Peter; Wang, Lihong V.; McLennan, Geoffrey; Hoffman, Eric A.; Wang, Ge

2004-10-01

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Analysis of Neurogenesis during Experimental Autoimmune Encephalomyelitis Reveals Pitfalls of Bioluminescence Imaging  

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Bioluminescence imaging is a sensitive approach for longitudinal neuroimaging. Transgenic mice expressing luciferase under the promoter of doublecortin (DCX-luc), a specific marker of neuronal progenitor cells (NPC), allow monitoring of neurogenesis in living mice. Since the extent and time course of neurogenesis during autoimmune brain inflammation are controversial, we investigated neurogenesis in MOG-peptide induced experimental allergic encephalomyelitis (EAE) using DCX-luc reporter mice. We observed a marked, 2- to 4-fold increase of the bioluminescence signal intensity 10 days after EAE induction and a gradual decline 1–2 weeks thereafter. In contrast, immunostaining for DCX revealed no differences between EAE and control mice 2 and 4 weeks after immunization in zones of adult murine neurogenesis such as the dentate gyrus. Ex vivo bioluminescence imaging showed similar luciferase expression in brain homogenates of EAE and control animals. Apart from complete immunization including MOG-peptide also incomplete immunization with complete Freund´s adjuvant and pertussis toxin resulted in a rapid increase of the in vivo bioluminescence signal. Blood-brain barrier (BBB) leakage was demonstrated 10 days after both complete and incomplete immunization and might explain the increased bioluminescence signal in vivo. We conclude, that acute autoimmune inflammation in EAE does not alter neurogenesis, at least at the stage of DCX-expressing NPC. Effects of immunization on the BBB integrity must be considered when luciferase is used as a reporter within the CNS during the active stage of EAE. Models with stable CNS-restricted luciferase expression could serve as technically convenient way to evaluate BBB integrity in a longitudinal manner. PMID:25780928

Metzdorf, Judith; Stahlke, Sarah; Pedreitturia, Xiomara; Hunfeld, Anika; Couillard-Despres, Sebastien; Kleiter, Ingo

2015-01-01

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In Vivo Bioluminescence Imaging of Cell Differentiation in Biomaterials: A Platform for Scaffold Development  

OpenAIRE

In vivo testing is a mandatory last step in scaffold development. Agile longitudinal noninvasive real-time monitoring of stem cell behavior in biomaterials implanted in live animals should facilitate the development of scaffolds for tissue engineering. We report on a noninvasive bioluminescence imaging (BLI) procedure for simultaneous monitoring of changes in the expression of multiple genes to evaluate scaffold performance in vivo. Adipose tissue-derived stromal mensenchymal cells were duall...

Bago?, Juli R.; Aguilar, Elisabeth; Alieva, Maria; Soler-botija, Carolina; Vila, Olaia F.; Claros, Silvia; Andrades, Jose? A.; Becerra, Jose?; Rubio, Nuria; Blanco, Jero?nimo

2012-01-01

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Assessing laser-tissue damage with bioluminescent imaging  

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Effective medical laser procedures are achieved by selecting laser parameters that minimize undesirable tissue damage. Traditionally, human subjects, animal models, and monolayer cell cultures have been used to study wound healing, tissue damage, and cellular effects of laser radiation. Each of these models has significant limitations, and consequently, a novel skin model is needed. To this end, a highly reproducible human skin model that enables noninvasive and longitudinal studies of gene expression was sought. In this study, we present an organotypic raft model (engineered skin) used in combination with bioluminescent imaging (BLI) techniques. The efficacy of the raft model was validated and characterized by investigating the role of heat shock protein 70 (hsp70) as a sensitive marker of thermal damage. The raft model consists of human cells incorporated into an extracellular matrix. The raft cultures were transfected with an adenovirus containing a murine hsp70 promoter driving transcription of luciferase. The model enables quantitative analysis of spatiotemporal expression of proteins using BLI. Thermal stress was induced on the raft cultures by means of a constant temperature water bath or with a carbon dioxide (CO2) laser (?=10.6 µm, 0.679 to 2.262 W/cm2, cw, unfocused Gaussian beam, ?L=4.5 mm, 1 min exposure). The bioluminescence was monitored noninvasively with an IVIS 100 Bioluminescent Imaging System. BLI indicated that peak hsp70 expression occurs 4 to 12 h after exposure to thermal stress. A minimum irradiance of 0.679 W/cm2 activated the hsp70 response, and a higher irradiance of 2.262 W/cm2 was associated with a severe reduction in hsp70 response due to tissue ablation. Reverse transcription polymerase chain reaction demonstrated that hsp70 mRNA levels increased with prolonged heating exposures. Enzyme-linked immunosorbent protein assays confirmed that luciferase was an accurate surrogate for hsp70 intracellular protein levels. Hematoxylin and eosin stains verified the presence of the thermally denatured tissue regions. Immunohistochemical analyses confirmed that maximal hsp70 expression occurred at a depth of 150 µm. Bioluminescent microscopy was employed to corroborate these findings. These results indicate that quantitative BLI in engineered tissue equivalents provides a powerful model that enables sequential gene expression studies. Such a model can be used as a high throughput screening platform for laser-tissue interaction studies.

Wilmink, Gerald J.; Opalenik, Susan R.; Beckham, Josh T.; Davidson, Jeffrey M.; Jansen, Eric D.

2006-07-01

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DEVELOPMENT OF A DUAL MODALITY TOMOGRAPHIC IMAGING SYSTEM FOR BIOLUMINESCENCE AND PET  

Energy Technology Data Exchange (ETDEWEB)

The goal of this proposal was to develop a new hybrid imaging modality capable to simultaneously image optical bioluminescence signals, as well as radionuclide emissions from the annihilation of positrons originating from molecular imaging probes in preclinical mouse models. This new technology enables the simultaneous in-vivo measurements of both emissions that could be produced from a single or a combination of two different biomarkers. It also facilitates establishing the physical limitations of bioluminescence imaging, its tomographic and spectral image reconstruction potential and the quantification of bioluminescence signals.

CHATZIIOANNOU, ARION

2011-12-21

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In Vivo Bioluminescence Imaging of Tumor Cells Using Optimized Firefly Luciferase luc2  

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Full Text Available The present study was aimed to establish a tumor cell line stably expressing luciferase luc2, and to develop the technique to observe primary tumor nodes and metastases using in vivo bioluminescence imaging. Materials and Methods. In this research we used pLuc2-N plasmid, lentiviral vector pLVT-1, Colo 26 cell line and BALB/c mice to generate new bioluminescent tumor model. Bioluminescence imaging in vitro ? in vivo was carried out on IVIS-Spectrum system (Caliper Life Sciences, USA. Primary tumor model was created by subcutaneous injection of 500 000 Colo 26-luc2 cells. Model of metastases was generated by i.v. injection of 75 000 Colo 26-luc2 cells. Histological analysis was performed to verify the results of the imaging. Results. We created the lentiviral vector containing luc2 gene using molecular cloning. Then Colo 26-luc2 tumor cell line was generated. We assessed the sensitivity of luc2-based bioluminescence imaging. The intensity of bioluminescent signal in vitro averaged about 5000 photon/s per cell, in vivo — 250 photon/sec per cell. In vivo monitoring of Colo 26-luc2 primary tumor and metastases was demonstrated. The results of bioluminescence imaging correlated with histological analysis data. Conclusion. The present work shows the possibility of bioluminescent system based on optimized luciferase luc2 for in vivo noninvasive high-sensitive whole-body imaging of tumors.

N.V. Klementyeva

2013-08-01

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Monitoring and quantitative assessment of tumor burden using in vivo bioluminescence imaging  

International Nuclear Information System (INIS)

In vivo bioluminescence imaging (BLI) is a sensitive imaging modality that is rapid and accessible, and may comprise an ideal tool for evaluating tumor growth. In this study, the kinetic of tumor growth has been assessed in C26 colon carcinoma bearing BALB/c mouse model. The ability of BLI to noninvasively quantitate the growth of subcutaneous tumors transplanted with C26 cells genetically engineered to stably express firefly luciferase and herpes simplex virus type-1 thymidine kinase (C26/tk-luc). A good correlation (R 2=0.998) of photon emission to the cell number was found in vitro. Tumor burden and tumor volume were monitored in vivo over time by quantitation of photon emission using Xenogen IVIS 50 and standard external caliper measurement, respectively. At various time intervals, tumor-bearing mice were imaged to determine the correlation of in vivo BLI to tumor volume. However, a correlation of BLI to tumor volume was observed when tumor volume was smaller than 1000 mm3 (R 2=0.907). ? Scintigraphy combined with [131I]FIAU was another imaging modality used for verifying the previous results. In conclusion, this study showed that bioluminescence imaging is a powerful and quantitative tool for the direct assay to monitor tumor growth in vivo. The dual reporter genes transfected tumor-bearing animal model can be applied in the evaluation of the efficacy of new developed anti-cancer drugsr drugs

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Multimodal imaging of orthotopic hepatocellular carcinoma using small animal PET, bioluminescence and contrast enhanced CT imaging  

Energy Technology Data Exchange (ETDEWEB)

Molecular imaging with small-animal PET and bioluminescence imaging has been used as an important tool in cancer research. One of the disadvantages of these imaging modalities is the lack of anatomic information. To obtain fusion images with both molecular and anatomical information, small-animal PET and bioluminescence images fused with contrast enhance CT image in orthotopic hepatocellular carcinoma (HCC) model. We retrovially transfected dual gene (HSV1-tk and firefly luciferase) to morris hepatoma cells. The expression of HSV1-tk and luciferase was checked by optical imager and in vitro radiolabeled FIAU uptake, respectively and also checked by RT-PCR analysis. MCA-TL cells (5X10{sup 5}/ 0.05 ml) mixed with matrigel (1: 10) injected into left lobe of liver in nude mice. {sup 124}I-FIAU-PET, bioluminescence and contrast enhanced CT images were obtained in the orthotopic HCC model and digital whole body autoradiography (DWBA) was performed. Small animal PET image was obtained at 2 h post injection of {sup 124}I-FIAU and contrast enhanced CT image was obtained at 3 h post injection of Fenestra LC (0.3 ml). MCA-TL cells showed more specific {sup 124}I-FIAU uptake and higher luminescent activity than parental cells. The orthotopic HCC was detected by {sup 124}I-FIAU PET, contrast enhanced CT, and BLI and confirmed by DWBA. Registered image in orthotopic HCC t models showed a good correlation of images from both PET and CT. Contrast enhanced CT image delineated margin of HCC. Multimodal imaging with {sup 124}I-FIAU PET, bioluminescence and contrast enhanced CT allows a precise and improved detection of tumor in orthotopic hepatocellular carcinoma model. Multimodal imaging is potentially useful for monitoring progression of hepatic metastasis and for the evaluation of cancer treatments.

Lee, T. S.; Woo, S. G.; Jeong, J. H.; Woo, K. S.; Jeong, E. S.; Kang, J. H.; Cheon, G. J.; Choi, C. W.; Lim, S. M. [Korea Institute of Radioligical and Medical Sciences, Seoul (Korea, Republic of)

2007-07-01

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Multimodal imaging of orthotopic hepatocellular carcinoma using small animal PET, bioluminescence and contrast enhanced CT imaging  

International Nuclear Information System (INIS)

Molecular imaging with small-animal PET and bioluminescence imaging has been used as an important tool in cancer research. One of the disadvantages of these imaging modalities is the lack of anatomic information. To obtain fusion images with both molecular and anatomical information, small-animal PET and bioluminescence images fused with contrast enhance CT image in orthotopic hepatocellular carcinoma (HCC) model. We retrovially transfected dual gene (HSV1-tk and firefly luciferase) to morris hepatoma cells. The expression of HSV1-tk and luciferase was checked by optical imager and in vitro radiolabeled FIAU uptake, respectively and also checked by RT-PCR analysis. MCA-TL cells (5X105/ 0.05 ml) mixed with matrigel (1: 10) injected into left lobe of liver in nude mice. 124I-FIAU-PET, bioluminescence and contrast enhanced CT images were obtained in the orthotopic HCC model and digital whole body autoradiography (DWBA) was performed. Small animal PET image was obtained at 2 h post injection of 124I-FIAU and contrast enhanced CT image was obtained at 3 h post injection of Fenestra LC (0.3 ml). MCA-TL cells showed more specific 124I-FIAU uptake and higher luminescent activity than parental cells. The orthotopic HCC was detected by 124I-FIAU PET, contrast enhanced CT, and BLI and confirmed by DWBA. Registered image in orthotopic HCC t models showed a good correlation of images from both PET and CT. Contrast enhanced CT rom both PET and CT. Contrast enhanced CT image delineated margin of HCC. Multimodal imaging with 124I-FIAU PET, bioluminescence and contrast enhanced CT allows a precise and improved detection of tumor in orthotopic hepatocellular carcinoma model. Multimodal imaging is potentially useful for monitoring progression of hepatic metastasis and for the evaluation of cancer treatments

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Real-Time Bioluminescent Tracking of Cellular Population Dynamics  

Energy Technology Data Exchange (ETDEWEB)

Cellular population dynamics are routinely monitored across many diverse fields for a variety of purposes. In general, these dynamics are assayed either through the direct counting of cellular aliquots followed by extrapolation to the total population size, or through the monitoring of signal intensity from any number of externally stimulated reporter proteins. While both viable methods, here we describe a novel technique that allows for the automated, non-destructive tracking of cellular population dynamics in real-time. This method, which relies on the detection of a continuous bioluminescent signal produced through expression of the bacterial luciferase gene cassette, provides a low cost, low time-intensive means for generating additional data compared to alternative methods.

Close, Dan [University of Tennessee, Knoxville (UTK); Sayler, Gary Steven [ORNL; Xu, Tingting [ORNL; Ripp, Steven Anthony [ORNL

2014-01-01

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Self-illuminating in vivo lymphatic imaging using a bioluminescence resonance energy transfer quantum dot nano-particle.  

Science.gov (United States)

Autofluorescence arising from normal tissues can compromise the sensitivity and specificity of in vivo fluorescence imaging by lowering the target-to-background signal ratio. Since bioluminescence resonance energy transfer quantum dot (BRET-QDot) nano-particles can self-illuminate in near-infrared in the presence of the substrate, coelenterazine, without irradiating excitation lights, imaging using BRET-QDots does not produce any autofluorescence. In this study, we applied this BRET-QDot nano-particle to the in vivo lymphatic imaging in mice in order to compare with BRET, fluorescence or bioluminescence lymphatic imaging. BRET-QDot655, in which QDot655 is contained as a core, was injected at different sites (e.g. chin, ear, forepaws and hind paws) in mice followed by the intravenous coelenterazine injection, and then bioluminescence and fluorescence imaging were serially performed. In all mice, each lymphatic basin was clearly visualized in the BRET imaging with minimal background signals. The BRET signal in the lymph nodes lasted at least 30 min after coelenterazine injections. Furthermore, the BRET signal demonstrated better quantification than the fluorescence signal emitting from QDot655, the core of this BRET particle. These advantages of BRET-QDot allowed us to perform real-time, quantitative lymphatic imaging without image processing. BRET-Qdots have the potential to be a robust nano-material platform for developing optical molecular imaging probes. PMID:21351373

Kosaka, Nobuyuki; Mitsunaga, Makoto; Bhattacharyya, Sukanta; Miller, Steven C; Choyke, Peter L; Kobayashi, Hisataka

2011-01-01

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In vivo bioluminescence imaging and histopathopathologic analysis reveal distinct roles for resident and recruited immune effector cells in defense against invasive aspergillosis  

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Full Text Available Abstract Background Invasive aspergillosis (IA is a major cause of infectious morbidity and mortality in immune compromised patients. Studies on the pathogenesis of IA have been limited by the difficulty to monitor disease progression in real-time. For real-time monitoring of the infection, we recently engineered a bioluminescent A. fumigatus strain. Results In this study, we demonstrate that bioluminescence imaging can track the progression of IA at different anatomic locations in a murine model of disease that recapitulates the natural route of infection. To define the temporal and functional requirements of distinct innate immune cellular subsets in host defense against respiratory A. fumigatus infection, we examined the development and progression of IA using bioluminescence imaging and histopathologic analysis in mice with four different types of pharmacologic or numeric defects in innate immune function that target resident and recruited phagocyte subsets. While bioluminescence imaging can track the progression and location of invasive disease in vivo, signals can be attenuated by severe inflammation and associated tissue hypoxia. However, especially under non-inflammatory conditions, such as cyclophosphamide treatment, an increasing bioluminescence signal reflects the increasing biomass of alive fungal cells. Conclusions Imaging studies allowed an in vivo correlation between the onset, peak, and kinetics of hyphal tissue invasion from the lung under conditions of functional or numeric inactivation of phagocytes and sheds light on the germination speed of conidia under the different immunosuppression regimens. Conditions of high inflammation -either mediated by neutrophil influx under corticosteroid treatment or by monocytes recruited during antibody-mediated depletion of neutrophils- were associated with rapid conidial germination and caused an early rise in bioluminescence post-infection. In contrast, 80% alveolar macrophage depletion failed to trigger a bioluminescent signal, consistent with the notion that neutrophil recruitment is essential for early host defense, while alveolar macrophage depletion can be functionally compensated.

Schwendener Reto

2010-04-01

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In vivo imaging of bioluminescent Pseudomonas aeruginosa in an acute murine airway infection model.  

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Non-invasive bioluminescence imaging allows the analysis of infectious diseases in small animal models. In this study, an acute airway infection of C3H/HeN mice with luxCDABE transformed Pseudomonas aeruginosa TBCF10839 and an isogenic transposon mutant was followed by optical imaging in vivo. Using the disease-causing dose of 2.0 × 10(6) CFU of the cystic fibrosis airway isolate TBCF10839, subtle luminescence of the lungs was inconsistently visible for the first hour after infection. Conversely, using a 100-fold higher dose of the strongly virulence-attenuated transposon mutant, the robust signal of bioluminescent bacteria increased over 24 h. To monitor murine airway infections with P. aeruginosa in vivo by bioluminescence, one should select an attenuated mutant of a virulent strain or a wild type strain that naturally lacks virulence determinants and/or that has acquired a low virulence persister phenotype by patho-adaptive mutations. PMID:24833236

Munder, Antje; Wölbeling, Florian; Klockgether, Jens; Wiehlmann, Lutz; Tümmler, Burkhard

2014-10-01

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Functional imaging of interleukin 1 beta expression in inflammatory process using bioluminescence imaging in transgenic mice  

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Full Text Available Abstract Background Interleukin 1 beta (IL-1? plays an important role in a number of chronic and acute inflammatory diseases. To understand the role of IL-1? in disease processes and develop an in vivo screening system for anti-inflammatory drugs, a transgenic mouse line was generated which incorporated the transgene firefly luciferase gene driven by a 4.5-kb fragment of the human IL-1? gene promoter. Luciferase gene expression was monitored in live mice under anesthesia using bioluminescence imaging in a number of inflammatory disease models. Results In a LPS-induced sepsis model, dramatic increase in luciferase activity was observed in the mice. This transgene induction was time dependent and correlated with an increase of endogenous IL-1? mRNA and pro-IL-1? protein levels in the mice. In a zymosan-induced arthritis model and an oxazolone-induced skin hypersensitivity reaction model, luciferase expression was locally induced in the zymosan injected knee joint and in the ear with oxazolone application, respectively. Dexamethasone suppressed the expression of luciferase gene both in the acute sepsis model and in the acute arthritis model. Conclusion Our data suggest that the transgenic mice model could be used to study transcriptional regulation of the IL-1? gene expression in the inflammatory process and evaluation the effect of anti-inflammatory drug in vivo.

Liu Zhihui

2008-08-01

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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%p 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 adapting optical imaging protocols to specific experimental settings when utilizing the firefly luciferase and d-luciferin system. (orig.)

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Rapid and Quantitative Assessment of Cancer Treatment Response Using In Vivo Bioluminescence Imaging  

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Full Text Available Current assessment of orthotopic tumor models in animals utilizes survival as the primary therapeutic end point. In vivo bioluminescence imaging (BLI is a sensitive imaging modality that is rapid and accessible, and may comprise an ideal tool for evaluating antineoplastic therapies [1 ]. Using human tumor cell lines constitutively expressing luciferase, the kinetics of tumor growth and response to therapy have been assessed in intraperitoneal [2], subcutaneous, and intravascular [3] cancer models. However, use of this approach for evaluating orthotopic tumor models has not been demonstrated. In this report, the ability of BLI to noninvasively quantitate the growth and therapeuticinduced cell kill of orthotopic rat brain tumors derived from 9L gliosarcoma cells genetically engineered to stably express firefly luciferase (9LLuc was investigated. Intracerebral tumor burden was monitored over time by quantitation of photon emission and tumor volume using a cryogenically cooled CCD camera and magnetic resonance imaging (MRI, respectively. There was excellent correlation (r=0.91 between detected photons and tumor volume. A quantitative comparison of tumor cell kill determined from serial MRI volume measurements and BLI photon counts following 1,3-bis(2-chloroethyl-1-nitrosourea (BCNU treatment revealed that both imaging modalities yielded statistically similar cell kill values (P=.951. These results provide direct validation of BLI imaging as a powerful and quantitative tool for the assessment of antineoplastic therapies in living animals.

Alnawaz Rehemtulla

2000-01-01

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Imaging of bubonic plague dynamics by in vivo tracking of bioluminescent Yersinia pestis.  

Science.gov (United States)

Yersinia pestis dissemination in a host is usually studied by enumerating bacteria in the tissues of animals sacrificed at different times. This laborious methodology gives only snapshots of the infection, as the infectious process is not synchronized. In this work we used in vivo bioluminescence imaging (BLI) to follow Y. pestis dissemination during bubonic plague. We first demonstrated that Y. pestis CO92 transformed with pGEN-luxCDABE stably emitted bioluminescence in vitro and in vivo, while retaining full virulence. The light produced from live animals allowed to delineate the infected organs and correlated with bacterial loads, thus validating the BLI tool. We then showed that the first step of the infectious process is a bacterial multiplication at the injection site (linea alba), followed by a colonization of the draining inguinal lymph node(s), and subsequently of the ipsilateral axillary lymph node through a direct connection between the two nodes. A mild bacteremia and an effective filtering of the blood stream by the liver and spleen probably accounted for the early bacterial blood clearance and the simultaneous development of bacterial foci within these organs. The saturation of the filtering capacity of the spleen and liver subsequently led to terminal septicemia. Our results also indicate that secondary lymphoid tissues are the main targets of Y. pestis multiplication and that colonization of other organs occurs essentially at the terminal phase of the disease. Finally, our analysis reveals that the high variability in the kinetics of infection is attributable to the time the bacteria remain confined at the injection site. However, once Y. pestis has reached the draining lymph nodes, the disease progresses extremely rapidly, leading to the invasion of the entire body within two days and to death of the animals. This highlights the extraordinary capacity of Y. pestis to annihilate the host innate immune response. PMID:22496846

Nham, Toan; Filali, Sofia; Danne, Camille; Derbise, Anne; Carniel, Elisabeth

2012-01-01

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Bioluminescent imaging: a critical tool in pre-clinical oncology research.  

LENUS (Irish Health Repository)

Bioluminescent imaging (BLI) is a non-invasive imaging modality widely used in the field of pre-clinical oncology research. Imaging of small animal tumour models using BLI involves the generation of light by luciferase-expressing cells in the animal following administration of substrate. This light may be imaged using an external detector. The technique allows a variety of tumour-associated properties to be visualized dynamically in living models. The increasing use of BLI as a small-animal imaging modality has led to advances in the development of xenogeneic, orthotopic, and genetically engineered animal models expressing luciferase genes. This review aims to provide insight into the principles of BLI and its applications in cancer research. Many studies to assess tumour growth and development, as well as efficacy of candidate therapeutics, have been performed using BLI. More recently, advances have also been made using bioluminescent imaging in studies of protein-protein interactions, genetic screening, cell-cycle regulators, and spontaneous cancer development. Such novel studies highlight the versatility and potential of bioluminescent imaging in future oncological research.

O'Neill, Karen

2010-02-01

25

Applications of Bioluminescence Imaging to Antiviral Research and Therapy: Multiple Luciferase Enzymes and Quantitation  

OpenAIRE

Bioluminescence imaging (BLI) has emerged as a powerful new modality for studies of viral infection and therapy in small animal models. BLI technology captures the light emitted from different luciferase enzymes to detect sites of viral infection and quantify viral replication in the context of a living animal. In this review, we discuss the biochemical features of various luciferase enzymes and modifications to these enzymes that can greatly enhance their ability to image viral infection, ho...

Luker, Kathryn E.; Luker, Gary D.

2008-01-01

26

Bioluminescence imaging to track bacterial dissemination of Yersinia pestis using different routes of infection in mice  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Plague is caused by Yersinia pestis, a bacterium that disseminates inside of the host at remarkably high rates. Plague bacilli disrupt normal immune responses in the host allowing for systematic spread that is fatal if left untreated. How Y. pestis disseminates from the site of infection to deeper tissues is unknown. Dissemination studies for plague are typically performed in mice by determining the bacterial burden in specific organs at various time points. To follow bacterial dissemination during plague infections in mice we tested the possibility of using bioluminescence imaging (BLI, an alternative non-invasive approach. Fully virulent Y. pestis was transformed with a plasmid containing the luxCDABE genes, making it able to produce light; this lux-expressing strain was used to infect mice by subcutaneous, intradermal or intranasal inoculation. Results We successfully obtained images from infected animals and were able to follow bacterial dissemination over time for each of the three different routes of inoculation. We also compared the radiance signal from animals infected with a wild type strain and a ?caf1?psaA mutant that we previously showed to be attenuated in colonization of the lymph node and systemic dissemination. Radiance signals from mice infected with the wild type strain were larger than values obtained from mice infected with the mutant strain (linear regression of normalized values, P? Conclusions We demonstrate that BLI is useful for monitoring dissemination from multiple inoculation sites, and for characterization of mutants with defects in colonization or dissemination.

Gonzalez Rodrigo J

2012-07-01

27

Quantitative Bioluminescent Imaging of Pre-Erythrocytic Malaria Parasite Infection Using Luciferase-Expressing Plasmodium yoelii  

OpenAIRE

The liver stages of Plasmodium parasites are important targets for the development of anti-malarial vaccine candidates and chemoprophylaxis approaches that aim to prevent clinical infection. Analyzing the impact of interventions on liver stages in the murine malaria model system Plasmodium yoelii has been cumbersome and requires terminal procedures. In vivo imaging of bioluminescent parasites has previously been shown to be an effective and non-invasive alternative to monitoring liver stage b...

Miller, Jessica L.; Murray, Sara; Vaughan, Ashley M.; Harupa, Anke; Sack, Brandon; Baldwin, Michael; Crispe, Ian N.; Kappe, Stefan H. I.

2013-01-01

28

Self-calibrated algorithms for diffuse optical tomography and bioluminescence tomography using relative transmission images  

OpenAIRE

Reconstruction algorithms for diffuse optical tomography (DOT) and bioluminescence tomography (BLT) have been developed based on diffusion theory. The algorithms numerically solve the diffusion equation using the finite element method. The direct measurements of the uncalibrated light fluence rates by a camera are used for the reconstructions. The DOT is self-calibrated by using all possible pairs of transmission images obtained with external sources along with the relative val...

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

2012-01-01

29

Compartment-specific bioluminescence imaging platform for the high-throughput evaluation of antitumor immune function  

OpenAIRE

Conventional assays evaluating antitumor activity of immune effector cells have limitations that preclude their high-throughput application. We adapted the recently developed Compartment-Specific Bioluminescence Imaging (CS-BLI) technique to perform high-throughput quantification of innate antitumor activity and to show how pharmacologic agents (eg, lenalidomide, pomalidomide, bortezomib, and dexamethasone) and autologous BM stromal cells modulate that activity. CS-BLI–based screening allow...

Mcmillin, Douglas W.; Delmore, Jake; Negri, Joseph M.; Vanneman, Matthew; Koyama, Shohei; Schlossman, Robert L.; Munshi, Nikhil C.; Laubach, Jacob; Richardson, Paul G.; Dranoff, Glenn; Anderson, Kenneth C.; Mitsiades, Constantine S.

2012-01-01

30

A bioluminescence imaging based in vivo model for preclinical testing of novel cellular immunotherapy strategies to improve the graft-versus-myeloma effect.  

OpenAIRE

Background: The development and preclinical testing of novel immunotherapy strategies for multiple myeloma can benefit substantially from a humanized animal model that enables quantitative real-time monitoring of tumor progression. Here we have explored the feasibility of establishing such a model in immunodeficient RAG2–/–c–/– mice, by utilizing non-invasive bioluminescent imaging for real-time monitoring of multiple myeloma cell growth. Design and Methods: Seven multiple myelom...

Rozemuller, H.; Spek, E.; Bogers-boer, L. H.; Zwart, M. C.; Verweij, V. G. M.; Emmelot, M. E.; Groen, R. W.; Spaapen, R. M.; Bloem, A. C.; Lokhorst, H. M.; Mutis, T.; Martens, A. C. M.

2008-01-01

31

In Vivo Imaging of Bioluminescent Escherichia coli in a Cutaneous Wound Infection Model for Evaluation of an Antibiotic Therapy  

OpenAIRE

A rapid, continuous method for noninvasively monitoring the effectiveness of several antibacterial agents in real time by using a model of wound infection was developed. This study was divided into three steps: (i) construction of a plasmid to transform Escherichia coli into a bioluminescent variant, (ii) study of the bioluminescent E. coli in vitro as a function of temperature and pH, and (iii) determination of the MIC and the minimal bactericidal concentration of sulfamethoxazole-trimethopr...

Jawhara, Samir; Mordon, Serge

2004-01-01

32

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

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Remote detection of human toxicants in real time using a human-optimized, bioluminescent bacterial luciferase gene cassette bioreporter  

Science.gov (United States)

Traditionally, human toxicant bioavailability screening has been forced to proceed in either a high throughput fashion using prokaryotic or lower eukaryotic targets with minimal applicability to humans, or in a more expensive, lower throughput manner that uses fluorescent or bioluminescent human cells to directly provide human bioavailability data. While these efforts are often sufficient for basic scientific research, they prevent the rapid and remote identification of potentially toxic chemicals required for modern biosecurity applications. To merge the advantages of high throughput, low cost screening regimens with the direct bioavailability assessment of human cell line use, we re-engineered the bioluminescent bacterial luciferase gene cassette to function autonomously (without exogenous stimulation) within human cells. Optimized cassette expression provides for fully endogenous bioluminescent production, allowing continuous, real time monitoring of the bioavailability and toxicology of various compounds in an automated fashion. To access the functionality of this system, two sets of bioluminescent human cells were developed. The first was programed to suspend bioluminescent production upon toxicological challenge to mimic the non-specific detection of a toxicant. The second induced bioluminescence upon detection of a specific compound to demonstrate autonomous remote target identification. These cells were capable of responding to ?M concentrations of the toxicant n-decanal, and allowed for continuous monitoring of cellular health throughout the treatment process. Induced bioluminescence was generated through treatment with doxycycline and was detectable upon dosage at a 100 ng/ml concentration. These results demonstrate that leveraging autonomous bioluminescence allows for low-cost, high throughput direct assessment of toxicant bioavailability.

Close, Dan; Webb, James; Ripp, Steven; Patterson, Stacey; Sayler, Gary

2012-06-01

34

Bioluminescence imaging of cord blood derived mesenchymal stem cell transplanatation into myocardium  

International Nuclear Information System (INIS)

The conventional method of analyzing myocardial cell transplanation relies on postmortem histology. We sought to demonstrate the feasibility of longitudinal monitoring transplanted cell survival in living animals using optical imaging techniques. Umblical cord blood was collected upon delivery with informed consent. Umblical mononuclear cells were obtained by negative immuno-depletion of CD3, CD14, CD19, CD38, CD66b, and glycophorin- A positive cells, followed by Ficoll- Paque density gradient centrifugation, and plated in non-coated tissue culture flasks in expansion medium. Cells were allowed to adhere overnight, thereafter non-adherent cells were washed out with medium changes. After getting the MSCs, they were transfected [multiplicity of infection (MOl) = 40) with Ad-CMV-Fluc overnight. Rats (n=4) underwent intramyocardial injection of 5 x 105 MSCs expressing firefly luciferase (Fluc) reporter gene. Optical bioluminescence imaging was performed using the charged-coupled device camera (Xenogen) from the 1st day of transplantion. Cardiac bioluminescence signals were present from 2nd day of transplantation. Cardiac signals were clearly present at day 2 (9.2x103p/s/cm2/sr). The signal reduced from day 3. The locations, magnitude, and survival duration of cord blood derived MSCs were monitored noninvasively. With further development, molecular imaging studies should add critical insights into cardiac cell transplantationardiac cell transplantation

35

Bioluminescence imaging of cord blood derived mesenchymal stem cell transplanatation into myocardium  

Energy Technology Data Exchange (ETDEWEB)

The conventional method of analyzing myocardial cell transplanation relies on postmortem histology. We sought to demonstrate the feasibility of longitudinal monitoring transplanted cell survival in living animals using optical imaging techniques. Umblical cord blood was collected upon delivery with informed consent. Umblical mononuclear cells were obtained by negative immuno-depletion of CD3, CD14, CD19, CD38, CD66b, and glycophorin- A positive cells, followed by Ficoll- Paque density gradient centrifugation, and plated in non-coated tissue culture flasks in expansion medium. Cells were allowed to adhere overnight, thereafter non-adherent cells were washed out with medium changes. After getting the MSCs, they were transfected [multiplicity of infection (MOl) = 40) with Ad-CMV-Fluc overnight. Rats (n=4) underwent intramyocardial injection of 5 x 10{sup 5} MSCs expressing firefly luciferase (Fluc) reporter gene. Optical bioluminescence imaging was performed using the charged-coupled device camera (Xenogen) from the 1st day of transplantion. Cardiac bioluminescence signals were present from 2nd day of transplantation. Cardiac signals were clearly present at day 2 (9.2x10{sup 3}p/s/cm{sup 2}/sr). The signal reduced from day 3. The locations, magnitude, and survival duration of cord blood derived MSCs were monitored noninvasively. With further development, molecular imaging studies should add critical insights into cardiac cell transplantation.

Min, Jung Joon; Ahn, Young Keun; Moon, Sung Min; Lim, Sang Yup; Yun, Kyung Ho; Heo, Young Jun; Song, Ho Chun; Jeong, Myung Ho; Bom, Hee Seung [School of Medicine, Chonnam National University, Gwangju (Korea, Republic of)

2004-07-01

36

Relation between deep bioluminescence and oceanographic variables: A statistical analysis using time-frequency decompositions  

Science.gov (United States)

We consider the statistical analysis of a 1.7-year high-frequency sampled time series, between 2009 and 2010, recorded at the ANTARES observatory in the deep NW Mediterranean Sea (2475 m depth). The objective was to estimate relationships between bioluminescence and environmental time series (temperature, salinity and current speed). As this entire dataset is characterized by non-linearity and non-stationarity, two time-frequency decomposition methods (wavelet and Hilbert-Huang) were used. These mathematical methods are dedicated to the analysis of a signal at various time and frequencies scales. This work propose some statistical tools dedicated to the study of relationships between two time series. Our study highlights three events of high bioluminescence activity in March 2009, December 2009 and March 2010. We demonstrate that the two events occurring in March 2009 and 2010 are correlated to the arrival of newly formed deep water masses at frequencies of approximately 4.8×10-7 (period of 24.1 days). In contrast, the event in December 2009 is only correlated with current speed at frequencies of approximately 1.9×10-6 (period of 6.0 days). The use of both wavelet and Hilbert-Huang transformations has proven to be successful for the analysis of multivariate time series. These methods are well-suited in a context of the increasing number of long time series recorded in oceanography.

Martini, S.; Nerini, D.; Tamburini, C.

2014-09-01

37

Self-calibrated algorithms for diffuse optical tomography and bioluminescence tomography using relative transmission images.  

Science.gov (United States)

Reconstruction algorithms for diffuse optical tomography (DOT) and bioluminescence tomography (BLT) have been developed based on diffusion theory. The algorithms numerically solve the diffusion equation using the finite element method. The direct measurements of the uncalibrated light fluence rates by a camera are used for the reconstructions. The DOT is self-calibrated by using all possible pairs of transmission images obtained with external sources along with the relative values of the simulated data and the calculated Jacobian. The reconstruction is done in the relative domain with the cancelation of any geometrical or optical factors. The transmission measurements for the DOT are used for calibrating the bioluminescence measurements at each wavelength and then a normalized system of equations is built up which is self-calibrated for the BLT. The algorithms have been applied to a three dimensional model of the mouse (MOBY) segmented into tissue regions which are assumed to have uniform optical properties. The DOT uses the direct method for calculating the Jacobian. The BLT uses a reduced space of eigenvectors of the Green's function with iterative shrinking of the permissible source region. The reconstruction results of the DOT and BLT algorithms show good agreement with the actual values when using either absolute or relative data. Even a small calibration error causes significant degradation of the reconstructions based on absolute data. PMID:23162719

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

2012-11-01

38

A fast full-body fluorescence/bioluminescence imaging system for small animals  

Science.gov (United States)

Whole body in vivo optical imaging of small animals has widened its applications and increased the capabilities for preclinical researches. However, most commercial and prototype optical imaging systems are camera-based systems using epi- or trans- illumination mode, with limited views of small animals. And for more accurate tomographic image reconstruction, additional data and information of a target animal is necessary. To overcome these issues, researchers have suggested several approaches such as maximizing the detection area or using the information of other highresolution modalities such as CT, MRI or Ultrasound, or using multi-spectral signals. As one of ways to maximizing the detection area of a target animal, we present a new fluorescence and bioluminescence imaging system for small animals, which can image entire surface of a target animal simultaneously. This system uses double mirror reflection scheme and it consists of input unit, imaging unit with two conical mirrors, the source illumination part and the surface scanner, and the detection unit with an intensified CCD camera system. Two conical mirrors are configured that a larger size mirror captures a target animal surface, and a smaller size mirror projects this captured image onto a CCD camera with one acquisition. With this scheme, we could capture entire surface of a target animal simultaneously and improve back reflection issue between a mirror and an animal surface of a single conical mirror scheme. Additionally, we could increase accessibility to an animal for multi-modality integration by providing unobstructed space around a target animal.

Lee, Jong Hwan; Kim, Hyun Keol; Jia, Jingfei; Fong, Christopher; Hielscher, Andreas H.

2013-03-01

39

Self-illuminating in vivo lymphatic imaging using a bioluminescence resonance energy transfer quantum dot nano-particle  

OpenAIRE

Autofluorescence arising from normal tissues can compromise the sensitivity and specificity of in vivo fluorescence imaging by lowering the target-to-background signal ratio. Since bioluminescence resonance energy transfer quantum dot (BRET-QDot) nano-particles can self-illuminate in near-infrared in the presence of the substrate, coelenterazine, without irradiating excitation lights, imaging using BRET-QDots does not produce any autofluorescence. In this study, we applied this BRET-QDot nano...

Kosaka, Nobuyuki; Mitsunaga, Makoto; Bhattacharyya, Sukanta; Miller, Steven C.; Choyke, Peter L.; Kobayashi, Hisataka

2010-01-01

40

Development of bioluminescent Salmonella strains for use in food safety  

Directory of Open Access Journals (Sweden)

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.

Bailey R Hartford

2008-01-01

41

A method for atlas-based volumetric registration with surface constraints for optical bioluminescence tomography in small animal imaging  

Science.gov (United States)

Atlases are normalized representations of anatomy that can provide a standard coordinate system for in vivo imaging studies. For Optical Bioluminescence Tomography (OBT) in small animals, the animal's surface topography can be reconstructed from structured light measurements, but internal anatomy is unavailable unless additional CT or MR images are acquired. We present a novel method for estimating the internal organ structure of a mouse by warping a labeled 3D volumetric mouse atlas with the constraint that the surfaces of the two should match. Surface-constrained harmonic maps used for this bijective warping are computed by minimizing the covariant harmonic energy. We demonstrate the application of this warping scheme in OBT, where scattering and absorption coefficients of tissue are functions of the internal anatomy and hence, better estimates of the organ structures can lead to a more accurate forward model resulting in improved source localization. We first estimated the subject's internal geometry using the atlas-based warping scheme. Then the mouse was tessellated and optical properties were assigned based on the estimated organ structure. Bioluminescent sources were simulated, an optical forward model was computed using a finite-element solver, and multispectral data were simulated. We evaluate the accuracy of the forward model computed using the warped atlas against that assuming a homogeneous mouse model. This is done by comparing each model against a 'true' optical forward model where the anatomy of the mouse is assumed known. We also evaluate the impact of anatomical alignment on bioluminescence source localization.

Chaudhari, Abhijit J.; Joshi, Anand A.; Darvas, Felix; Leahy, Richard M.

2007-03-01

42

Time-resolved fluorescence spectroscopic study of flavin fluorescence in purified enzymes of bioluminescent bacteria  

Science.gov (United States)

Time-resolved fluorescence intensity and anisotropy decay measurements have been used to study the environment and rotational mobility of endogenous flavin in two purified enzymes of bioluminescent bacteria, Luciferase from Photobacterium leiognathi and NAD(P)H:FMN-oxidoreductase from Vibrio fischeri. We compared the time-resolved fluorescence parameters, intensity decay lifetimes, rotational correlation times, and their fractional contribution, of the endogeneous flavin fluorescence in each of the two enzymes in the presence or absence of quinones of different structures and redox potentials. The endogeneous flavin exhibited multi-exponential decay characteristics as compared to a single decay lifetime of around 5 ns for free flavin, suggesting a complex and heterogeneous environment of flavin bound to the enzyme. In addition, a significant increase in the rotational correlation time and a certain degree of ordering of the molecule were observed for endogenous flavin when compared to a single and fast rotational correlation time of 150 ps of free flavin. Quinone significantly altered both the lifetime and rotational characteristics of endogenous flavin suggesting specific interactions of quinones to the endogeneous flavin in the bacterial enzyme.

Vetrova, Elena; Kudryasheva, N.; Cheng, K.

2006-10-01

43

Evaluation of monkeypox virus infection of prairie dogs (Cynomys ludovicianus) using in vivo bioluminescent imaging  

Science.gov (United States)

Monkeypox (MPX) is a re-emerging zoonotic disease that is endemic in Central and West Africa, where it can cause a smallpox-like disease in humans. Despite many epidemiologic and field investigations of MPX, no definitive reservoir species has been identified. Using recombinant viruses expressing the firefly luciferase (luc) gene, we previously demonstrated the suitability of in vivo bioluminescent imaging (BLI) to study the pathogenesis of MPX in animal models. Here, we evaluated BLI as a novel approach for tracking MPX virus infection in black-tailed prairie dogs (Cynomys ludovicianus). Prairie dogs were affected during a multistate outbreak of MPX in the US in 2003 and have since been used as an animal model of this disease. Our BLI results were compared with PCR and virus isolation from tissues collected postmortem. Virus was easily detected and quantified in skin and superficial tissues by BLI before and during clinical phases, as well as in subclinical secondary cases, but was not reliably detected in deep tissues such as the lung. Although there are limitations to viral detection in larger wild rodent species, BLI can enhance the use of prairie dogs as an animal model of MPX and can be used for the study of infection, disease progression, and transmission in potential wild rodent reservoirs.

Falendysz, Elizabeth A.; Londoño-Navas, Angela M.; Meteyer, Carol U.; Pussini, Nicola; Lopera, Juan G.; Osorio, Jorge E.; Rocke, Tonie E.

2014-01-01

44

Noninvasive bioluminescence imaging of ?-synuclein oligomerization in mouse brain using split firefly luciferase reporters.  

Science.gov (United States)

Alpha-synuclein (?SYN) aggregation plays a pivotal role in the pathogenesis of Parkinson's disease and other synucleinopathies. In this multistep process, oligomerization of ?SYN monomers is the first step in the formation of fibrils and intracytoplasmic inclusions. Although ?SYN oligomers are generally considered to be the culprit of these diseases, the methodology currently available to follow-up oligomerization in cells and in brain is inadequate. We developed a split firefly luciferase complementation system to visualize oligomerization of viral vector-encoded ?SYN fusion proteins. ?SYN oligomerization resulted in successful luciferase complementation in cell culture and in mouse brain. Oligomerization of ?SYN was monitored noninvasively with bioluminescence imaging in the mouse striatum and substantia nigra up to 8 months after injection. Moreover, the visualized ?SYN oligomers retained their toxic and aggregation properties in both model systems. Next, the effect of two small molecules, FK506 and (-)-epigallocatechin-3-gallate (EGCG), known to inhibit ?SYN fibril formation, was investigated. FK506 inhibited the observed ?SYN oligomerization both in cell culture and in mouse brain. In conclusion, the split firefly luciferase-?SYN complementation assay will increase our insight in the role of ?SYN oligomers in synucleinopathies and opens new opportunities to evaluate potential ?SYN-based neuroprotective therapies. PMID:25471588

Aelvoet, Sarah-Ann; Ibrahimi, Abdelilah; Macchi, Francesca; Gijsbers, Rik; Van den Haute, Chris; Debyser, Zeger; Baekelandt, Veerle

2014-12-01

45

Real-time monitoring of bioaerosols via cell-lysis by air ion and ATP bioluminescence detection.  

Science.gov (United States)

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. PMID:24080217

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

2014-02-15

46

Establishment of cell strains stably-transfected with luciferase gene mediated by retrovirus and their detection with bioluminescence imaging system  

Directory of Open Access Journals (Sweden)

Full Text Available Objective ?To establish cell strains stably transfected with Luciferase gene (Luc2, which was mediated by retrovirus, and explore the relationship between the number of Luc2-positive cells and light flux from bioluminescence imaging system by experiments in vitro and in vivo. Methods ?We co-transfected pMX-Luc2 plasmid and pMD.G plasmid into 293T gag-pol cells to get retrovirus expressing Luc2 gene. Stable Luc2 positive cell lines were generated and screened by transduction of Retro-Luc2 in mouse colon cancer cell line CT26, human non-small cell lung cancer cell line NCI-H446, human colon cancer cell line HT-29, human ovarian carcinoma cell line SKOV3 and human hepatocellular carcinoma cell line SMMC-7721, all of them were identified by bioluminescence imaging system. Different numbers of SKOV3-Luc2 cells ranging from 10 to 10000 were plated onto culture dishes. Two xenograft models of ovarian cancer were reproduced by subcutaneous injection of 200?l SKOV3-Luc2 cell suspension with different concentrations (1×107, 5×106, 2.5×106, 1×106, 5×105, 2.5×105, 1×105 and 5×104/ml into 16 sites on the back of 4 nude mice, or intravenous injection of 1×106 or 3 ×106 SKOV3-Luc2 cells into the tail vein. Light flux value of SKOV3-Luc2 cells in dishes and in mice was measured by bioluminescence imaging system. Results ?Retro-Luc2 was constructed successfully and expressed Luc2 stably in transduced CT26, NCI-H446, HT-29, SKOV3 and SMMC-7721 cell lines. Light flux was correlated in a linear manner with the number of Luc2-positive cells in dishes and in mice (R2=0.944, ?=0.972; R2=0.991, ?=0.996; R2=0.351, ?=0.628; P < 0.01. Conclusion ?Luc2-positive cell lines could be established rapidly and accurately by infecting tumor cells with retrovirus expressing Luc2. The number of Luc2 positive cells is significantly related in a linear manner to light flux from bioluminescence imaging system in vitro and in vivo.

Hai-juan WANG

2012-05-01

47

Effect of optical property estimation accuracy on tomographic bioluminescence imaging: simulation of a combined optical-PET (OPET) system  

International Nuclear Information System (INIS)

Inevitable discrepancies between the mouse tissue optical properties assumed by an experimenter and the actual physiological values may affect the tomographic localization of bioluminescent sources. In a previous work, the simplifying assumption of optically homogeneous tissues led to inaccurate localization of deep sources. Improved results may be obtained if a mouse anatomical map is provided by a high-resolution imaging modality and optical properties are assigned to segmented tissues. In this work, the feasibility of this approach was explored by simulating the effect of different magnitude optical property errors on the image formation process of a combined optical-PET system. Some comparisons were made with corresponding simulations using higher spatial resolution data that are typically attainable by CCD cameras. In addition, simulation results provided insights on some of the experimental conditions that could lead to poor localization of bioluminescent sources. They also provided a rough guide on how accurately tissue optical properties need to be known in order to achieve correct localization of point sources with increasing tissue depth under low background noise conditions

48

Destabilized bioluminescent proteins  

Science.gov (United States)

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.

Allen, Michael S. (Knoxville, TN); Rakesh, Gupta (New Delhi, IN); Gary, Sayler S. (Blaine, TN)

2007-07-31

49

Characterization of two mouse models of metastatic pheochromocytoma using bioluminescence imaging  

OpenAIRE

Pheochromocytoma is the most common tumor of the adrenal medulla in adults. The lack of sensitive animal models of pheochromocytoma has hindered the study of this tumor and in vivo evaluation of antitumor agents. In this study we generated two sensitive luciferase models using bioluminescent pheochromocytoma cells: an experimental metastasis model to monitor tumor spreading and a subcutaneous model to monitor tumor growth and spontaneous metastasis. These models offer a platform for sensitive...

Giubellino, Alessio; Woldemichael, Girma M.; Sourbier, Carole; Lizak, Martin J.; Powers, James F.; Tischler, Arthur S.; Pacak, Karel

2011-01-01

50

Measuring Cytotoxicity by Bioluminescence Imaging Outperforms the Standard Chromium-51 Release Assay  

OpenAIRE

The chromium-release assay developed in 1968 is still the most commonly used method to measure cytotoxicity by T cells and by natural killer cells. Target cells are loaded in vitro with radioactive chromium and lysis is determined by measuring chromium in the supernatant released by dying cells. Since then, alternative methods have been developed using different markers of target cell viability that do not involve radioactivity. Here, we compared and contrasted a bioluminescence (BLI)-based c...

Karimi, Mobin A.; Lee, Eric; Bachmann, Michael H.; Salicioni, Ana Maria; Behrens, Edward M.; Kambayashi, Taku; Baldwin, Cynthia L.

2014-01-01

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A Bone Metastasis Nude Mouse Model Created by Ultrasound Guided Intracardiac Injection of Breast Cancer Cells: the Micro-CT, MRI and Bioluminescence Imaging Analysis  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to develop a nude mouse model of bone metastasis by performing intracardiac injection of breast cancer cells under ultrasonography guidance and we wanted to evaluate the development and the distribution of metastasis in vivo using micro-CT, MRI and bioluminescence imaging. Animal experiments were performed in 6-week-old female nude mice. The animals underwent left ventricular injection of 2x105 MDA-MB-231Bo-Luc cells. After injection of the tumor cells, serial bioluminescence imaging was performed for 7 weeks. The findings of micro-CT, MRI and the histology were correlated with the 'hot' lesions seen on the bioluminescence imaging. Metastasis was found in 62.3% of the animals. Two weeks after intracardiac injection, metastasis to the brain, spine and femur was detected with bioluminescence imaging with an increasing intensity by week 7. Micro-CT scan confirmed multiple osteolytic lesions at the femur, spine and skull. MRI and the histology were able to show metastasis in the brain and extraskeletal metastasis around the femur. The intracardiac injection of cancer cells under ultrasonography guidance is a safe and highly reproducible method to produce bone metastasis in nude mice. This bone metastasis nude mouse model will be useful to study the mechanism of bone metastasis and to validate new therapeutics

Park, Young Jin; Song, Eun Hye; Kim, Seol Hwa; Song, Ho Taek; Suh, Jin Suck [Yonsei University College of Medicine, Seoul (Korea, Republic of); Choi, Sang Hyun [Korean Minjok Leadership Academy, Heongsung (Korea, Republic of)

2011-01-15

52

A Bone Metastasis Nude Mouse Model Created by Ultrasound Guided Intracardiac Injection of Breast Cancer Cells: the Micro-CT, MRI and Bioluminescence Imaging Analysis  

International Nuclear Information System (INIS)

The purpose of this study was to develop a nude mouse model of bone metastasis by performing intracardiac injection of breast cancer cells under ultrasonography guidance and we wanted to evaluate the development and the distribution of metastasis in vivo using micro-CT, MRI and bioluminescence imaging. Animal experiments were performed in 6-week-old female nude mice. The animals underwent left ventricular injection of 2x105 MDA-MB-231Bo-Luc cells. After injection of the tumor cells, serial bioluminescence imaging was performed for 7 weeks. The findings of micro-CT, MRI and the histology were correlated with the 'hot' lesions seen on the bioluminescence imaging. Metastasis was found in 62.3% of the animals. Two weeks after intracardiac injection, metastasis to the brain, spine and femur was detected with bioluminescence imaging with an increasing intensity by week 7. Micro-CT scan confirmed multiple osteolytic lesions at the femur, spine and skull. MRI and the histology were able to show metastasis in the brain and extraskeletal metastasis around the femur. The intracardiac injection of cancer cells under ultrasonography guidance is a safe and highly reproducible method to produce bone metastasis in nude mice. This bone metastasis nude mouse model will be useful to study the mechanism of bone metastasis and to validate new therapeutics

53

Evaluation of impaired beta-cell function in nonobese-diabetic (NOD) mouse model using bioluminescence imaging.  

Science.gov (United States)

Insulin-producing pancreatic ? cells are functionally impaired or destroyed in diabetes mellitus. The onset of type 1 diabetes (T1D) represents the culmination of a prolonged prediabetic phase of immune-mediated ?-cell destruction. To assess the in vivo metabolic status of these cells, we used the ATP-sensitive firefly luciferase bioluminescence imaging approach, as a noninvasive probe to monitor pathological alterations in ?-cell function in the nonobese-diabetic (NOD) mouse model of T1D. Hence, we generated the ToI?-NOD transgenic mice in which doxycycline-inducible luciferase gene is selectively expressed in ? cells. A sharp reduction in bioluminescence emitted in vivo from ? cells at the early stages, preceded by several weeks of a limited reduction in ?-cell mass. Since this decline could be due to the ongoing inflammatory process occurring in vivo, we exposed control islets to inflammatory cytokines and observed a dramatic decrease in luciferase luminescence, which appears to be due in part to a decrease in protein levels and a drop in intracellular ATP levels. This is the first evidence that selective expression of the luciferase gene represents a sensitive method for noninvasive in vivo monitoring of early ?-cell dysfunction, subtle metabolic changes, such as endogenous ATP levels, indicative of a pathological condition in a tissue at the cellular level. PMID:21118902

Sever, Dror; Eldor, Roy; Sadoun, Gadi; Amior, Livnat; Dubois, Daniele; Boitard, Christian; Aflalo, Claude; Melloul, Danielle

2011-02-01

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Candida albicans Biofilm Development on Medically-relevant Foreign Bodies in a Mouse Subcutaneous Model Followed by Bioluminescence Imaging.  

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Candida albicans biofilm development on biotic and/or abiotic surfaces represents a specific threat for hospitalized patients. So far, C. albicans biofilms have been studied predominantly in vitro but there is a crucial need for better understanding of this dynamic process under in vivo conditions. We developed an in vivo subcutaneous rat model to study C. albicans biofilm formation. In our model, multiple (up to 9) Candida-infected devices are implanted to the back part of the animal. This gives us a major advantage over the central venous catheter model system as it allows us to study several independent biofilms in one animal. Recently, we adapted this model to study C. albicans biofilm development in BALB/c mice. In this model, mature C. albicans biofilms develop within 48 hr and demonstrate the typical three-dimensional biofilm architecture. The quantification of fungal biofilm is traditionally analyzed post mortem and requires host sacrifice. Because this requires the use of many animals to perform kinetic studies, we applied non-invasive bioluminescence imaging (BLI) to longitudinally follow up in vivo mature C. albicans biofilms developing in our subcutaneous model. C. albicans cells were engineered to express the Gaussia princeps luciferase gene (gLuc) attached to the cell wall. The bioluminescence signal is produced by the luciferase that converts the added substrate coelenterazine into light that can be measured. The BLI signal resembled cell counts obtained from explanted catheters. Non-invasive imaging for quantifying in vivo biofilm formation provides immediate applications for the screening and validation of antifungal drugs under in vivo conditions, as well as for studies based on host-pathogen interactions, hereby contributing to a better understanding of the pathogenesis of catheter-associated infections. PMID:25651138

Kucharíková, So?a; Vande Velde, Greetje; Himmelreich, Uwe; Van Dijck, Patrick

2015-01-01

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Synthetic strategies for controlling inter- and intramolecular interactions: Applications in single-molecule fluorescence imaging, bioluminescence imaging, and palladium catalysis  

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The field of synthetic organic chemistry has reached such maturity that, with sufficient effort and resources, the synthesis of virtually any small molecule which exhibits reasonable stability at room temperature can be realized. While representing a monumental achievement for the field, the ability to exert precise control over molecular structure is just a means to an end, and it is frequently the responsibility of the synthetic chemist to determine which molecules should actually be synthesized. For better or worse, there exists no competitive free market in academia for new molecules, and as a result, the decision of which compounds should be synthesized is seldom driven by the forces of supply and demand; rather, it is guided by the synthetic chemist's interest in an anticipated structure-function relationship or in the properties of a previously unstudied class of molecules. As a consequence, there exists a pervasive need for chemists with synthetic expertise in fields (e.g., molecular imaging) and subdisciplines of chemistry (e.g., physical chemistry) in which the identification of promising synthetic targets dramatically outpaces the synthetic output in that field or subdiscipline, and ample opportunities are available for synthetic chemists who choose to pursue such cross-disciplinary research. This thesis describes synthetic efforts that leverage these opportunities to realize applications in biological imaging and in palladium catalysis. In Part I, the synthesis and characterization of three novel luminophores and their imaging applications are discussed. The first is a molecular beacon that utilizes a fluorophorefluorophore pair which exhibits H-dimer quenching in the closed conformation. This probe offers several advantages over conventional fluorophore-quencher molecular beacons in the detection of oligonucleotides, both in bulk and at the single-molecule level. Secondly, a fluorescent, Cy3-Cy5 covalent heterodimer is reported, which on account of the proximity of the Cy3 and Cy5 fluorophores, behaves as an optical photoswitch in the presence of a thiol reagent. This unique property was employed to achieve sub-diffraction-limited imaging of the stalks of Caulobacter crescentus cells with 30-nm resolution using STORM (stochastic optical reconstruction microscopy). Lastly, the synthesis of the first selenium analogue of firefly luciferin is described, and this analogue is shown to be a competent substrate for firefly luciferase (fLuc). Remarkably, it exhibits red-shifted bioluminescence emission relative to the native sulfur analogue. The in vivo performance of the selenium and sulfur analogues in imaging are compared by tail-vein injection into nude mice bearing subcutaneous tumor xenografts of a human breast cancer cell line that was stably transduced to express fLuc. Part II of this thesis begins by addressing design considerations in the development of palladium catalysts that effect oxidative transformations under mild conditions (i.e., 1 atm air, room temperature) using molecular oxygen as the terminal oxidant. A newly synthesized cationic palladium complex, [(2,9-dimethylphenanthroline)Pd(OAc)]2[OTf]2, is shown to catalyze aerobic alcohol oxidation under such conditions with an unprecedented initial turnover frequency, but the presence of partially reduced oxygen species results in competitive ligand oxidation with concomitant decrease in catalyst activity. To remedy this, oxidatively resistant ligands, which are essential for the development of next-generation, high-turnover-frequency palladium catalysts that utilize oxygen as a terminal oxidant, have been prepared and effectively employed. In addition, the first general palladium-catalyzed route to the carbonylation of diols is reported. In this system, carbon monoxide (1 atm) serves the carbonyl source, (2,9-dimethylphenanthroline)Pd(OAc) 2 acts as the catalyst, and N-chlorosuccinimide and iodosobenzene are the oxidants for 1,2- and 1,3-diols, respectively. This thesis illustrates the power of synthetic organic chemistry to exert precise control ove

Conley, Nicholas R.

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Live imaging of bioluminescent leptospira interrogans in mice reveals renal colonization as a stealth escape from the blood defenses and antibiotics.  

Science.gov (United States)

Leptospira (L.) interrogans are bacteria responsible for a worldwide reemerging zoonosis. Some animals asymptomatically carry L. interrogans in their kidneys and excrete bacteria in their urine, which contaminates the environment. Humans are infected through skin contact with leptospires and develop mild to severe leptospirosis. Previous attempts to construct fluorescent or bioluminescent leptospires, which would permit in vivo visualization and investigation of host defense mechanisms during infection, have been unsuccessful. Using a firefly luciferase cassette and random transposition tools, we constructed bioluminescent chromosomal transformants in saprophytic and pathogenic leptospires. The kinetics of leptospiral dissemination in mice, after intraperitoneal inoculation with a pathogenic transformant, was tracked by bioluminescence using live imaging. For infective doses of 106 to 107 bacteria, we observed dissemination and exponential growth of leptospires in the blood, followed by apparent clearance of bacteria. However, with 2×108 bacteria, the septicemia led to the death of mice within 3 days post-infection. In surviving mice, one week after infection, pathogenic leptospires reemerged only in the kidneys, where they multiplied and reached a steady state, leading to a sustained chronic renal infection. These experiments reveal that a fraction of the leptospiral population escapes the potent blood defense, and colonizes a defined number of niches in the kidneys, proportional to the infective dose. Antibiotic treatments failed to eradicate leptospires that colonized the kidneys, although they were effective against L. interrogans if administered before or early after infection. To conclude, mice infected with bioluminescent L. interrogans proved to be a novel model to study both acute and chronic leptospirosis, and revealed that, in the kidneys, leptospires are protected from antibiotics. These bioluminescent leptospires represent a powerful new tool to challenge mice treated with drugs or vaccines, and test the survival, dissemination, and transmission of leptospires between environment and hosts. PMID:25474719

Ratet, Gwenn; Veyrier, Frédéric J; Fanton d'Andon, Martine; Kammerscheit, Xavier; Nicola, Marie-Anne; Picardeau, Mathieu; Boneca, Ivo G; Werts, Catherine

2014-12-01

57

Measuring cytotoxicity by bioluminescence imaging outperforms the standard chromium-51 release assay.  

Science.gov (United States)

The chromium-release assay developed in 1968 is still the most commonly used method to measure cytotoxicity by T cells and by natural killer cells. Target cells are loaded in vitro with radioactive chromium and lysis is determined by measuring chromium in the supernatant released by dying cells. Since then, alternative methods have been developed using different markers of target cell viability that do not involve radioactivity. Here, we compared and contrasted a bioluminescence (BLI)-based cytotoxicity assay to the standard radioactive chromium-release assay using an identical set of effector cells and tumor target cells. For this, we stably transduced several human and murine tumor cell lines to express luciferase. When co-cultured with cytotoxic effector cells, highly reproducible decreases in BLI were seen in an effector to target cell dose-dependent manner. When compared to results obtained from the chromium release assay, the performance of the BLI-based assay was superior, because of its robustness, increased signal-to-noise ratio, and faster kinetics. The reduced/delayed detection of cytotoxicity by the chromium release method was attributable to the association of chromium with structural components of the cell, which are released quickly by detergent solubilization but not by hypotonic lysis. We conclude that the (BLI)-based measurement of cytotoxicity offers a superior non-radioactive alternative to the chromium-release assay that is more robust and quicker to perform. PMID:24586714

Karimi, Mobin A; Lee, Eric; Bachmann, Michael H; Salicioni, Ana Maria; Behrens, Edward M; Kambayashi, Taku; Baldwin, Cynthia L

2014-01-01

58

Evaluation of bioluminescent imaging for noninvasive monitoring of colorectal cancer progression in the liver and its response to immunogene therapy  

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Full Text Available Abstract Background Bioluminescent imaging (BLI is based on the detection of light emitted by living cells expressing a luciferase gene. Stable transfection of luciferase in cancer cells and their inoculation into permissive animals allows the noninvasive monitorization of tumor progression inside internal organs. We have applied this technology for the development of a murine model of colorectal cancer involving the liver, with the aim of improving the pre-clinical evaluation of new anticancer therapies. Results A murine colon cancer cell line stably transfected with the luciferase gene (MC38Luc1 retains tumorigenicity in immunocompetent C57BL/6 animals. Intrahepatic inoculation of MC38Luc1 causes progressive liver infiltration that can be monitored by BLI. Compared with ultrasonography (US, BLI is more sensitive, but accurate estimation of tumor mass is impaired in advanced stages. We applied BLI to evaluate the efficacy of an immunogene therapy approach based on the liver-specific expression of the proinflammatory cytokine interleukin-12 (IL-12. Individualized quantification of light emission was able to determine the extent and duration of antitumor responses and to predict long-term disease-free survival. Conclusion We show that BLI is a rapid, convenient and safe technique for the individual monitorization of tumor progression in the liver. Evaluation of experimental treatments with complex mechanisms of action such as immunotherapy is possible using this technology.

Gonzalez-Aparicio Manuela

2009-01-01

59

Evaluation of monkeypox virus infection of black-tailed prairie dogs (Cynomys ludovicianus) using in vivo bioluminescent imaging.  

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Monkeypox (MPX) is a re-emerging zoonotic disease that is endemic in Central and West Africa, where it can cause a smallpox-like disease in humans. Despite many epidemiologic and field investigations of MPX, no definitive reservoir species has been identified. Using recombinant viruses expressing the firefly luciferase (luc) gene, we previously demonstrated the suitability of in vivo bioluminescent imaging (BLI) to study the pathogenesis of MPX in animal models. Here, we evaluated BLI as a novel approach for tracking MPX virus infection in black-tailed prairie dogs (Cynomys ludovicianus). Prairie dogs were affected during a multistate outbreak of MPX in the US in 2003 and have since been used as an animal model of this disease. Our BLI results were compared with PCR and virus isolation from tissues collected postmortem. Virus was easily detected and quantified in skin and superficial tissues by BLI before and during clinical phases, as well as in subclinical secondary cases, but was not reliably detected in deep tissues such as the lung. Although there are limitations to viral detection in larger wild rodent species, BLI can enhance the use of prairie dogs as an animal model of MPX and can be used for the study of infection, disease progression, and transmission in potential wild rodent reservoirs. PMID:24779460

Falendysz, Elizabeth A; Londoño-Navas, Angela M; Meteyer, Carol U; Pussini, Nicola; Lopera, Juan G; Osorio, Jorge E; Rocke, Tonie E

2014-07-01

60

Bioluminescent Web Page  

Science.gov (United States)

This highly acclaimed website includes information on bioluminescence research, myths, photos, organisms, chemistry, physiology, distribution and more. Features an absolute must-see bioluminescence photo gallery. Also includes submitted abstracts and journal citations concerning bioluminescence, as well as proceedings from several related symposia. The chemistry section has molecular diagrams and several animated illustrations that explain the reaction behind fluorescence.

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Comparative live bioluminescence imaging of monkeypox virus dissemination in a wild-derived inbred mouse (Mus musculus castaneus) and outbred African dormouse (Graphiurus kelleni).  

Science.gov (United States)

Monkeypox virus belongs to the orthopoxvirus genus, infects rodents and monkeys in Africa, produces a smallpox-like zoonotic disease in humans, and has the potential for global spread and exploitation for bioterrorism. Several small animal models for studying monkeypox virus pathogenesis have been investigated. The African dormouse is a candidate natural host but is outbred and no immunological reagents exist. Although not a natural host, the CAST/EiJ mouse is inbred and animals and reagents are commercially available. We compared the dissemination of monkeypox virus by bioluminescence imaging in CAST/EiJ mice and dormice. In CAST/EiJ mice, intense replication occurred at the intranasal site of inoculation and virus spread rapidly to lungs and abdominal organs, which had a lower virus burden. Compared to CAST/EiJ mice, dormice exhibited a greater variation of virus spread, a slower time course, less replication in the head and chest, and more replication in abdominal organs prior to death. PMID:25462355

Earl, Patricia L; Americo, Jeffrey L; Cotter, Catherine A; Moss, Bernard

2015-01-15

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Rational development of an attenuated recombinant cyprinid herpesvirus 3 vaccine using prokaryotic mutagenesis and in vivo bioluminescent imaging.  

Science.gov (United States)

Cyprinid herpesvirus 3 (CyHV 3) is causing severe economic losses worldwide in common and koi carp industries, and a safe and efficacious attenuated vaccine compatible with mass vaccination is needed. We produced single deleted recombinants using prokaryotic mutagenesis. When producing a recombinant lacking open reading frame 134 (ORF134), we unexpectedly obtained a clone with additional deletion of ORF56 and ORF57. This triple deleted recombinant replicated efficiently in vitro and expressed an in vivo safety/efficacy profile compatible with use as an attenuated vaccine. To determine the role of the double ORF56-57 deletion in the phenotype and to improve further the quality of the vaccine candidate, a series of deleted recombinants was produced and tested in vivo. These experiments led to the selection of a double deleted recombinant lacking ORF56 and ORF57 as a vaccine candidate. The safety and efficacy of this strain were studied using an in vivo bioluminescent imaging system (IVIS), qPCR, and histopathological examination, which demonstrated that it enters fish via skin infection similar to the wild type strain. However, compared to the parental wild type strain, the vaccine candidate replicated at lower levels and spread less efficiently to secondary sites of infection. Transmission experiments allowing water contamination with or without additional physical contact between fish demonstrated that the vaccine candidate has a reduced ability to spread from vaccinated fish to naïve sentinel cohabitants. Finally, IVIS analyses demonstrated that the vaccine candidate induces a protective mucosal immune response at the portal of entry. Thus, the present study is the first to report the rational development of a recombinant attenuated vaccine against CyHV 3 for mass vaccination of carp. We also demonstrated the relevance of the CyHV 3 carp model for studying alloherpesvirus transmission and mucosal immunity in teleost skin. PMID:25700279

Boutier, Maxime; Ronsmans, Maygane; Ouyang, Ping; Fournier, Guillaume; Reschner, Anca; Rakus, Krzysztof; Wilkie, Gavin S; Farnir, Frédéric; Bayrou, Calixte; Lieffrig, François; Li, Hong; Desmecht, Daniel; Davison, Andrew J; Vanderplasschen, Alain

2015-02-01

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GMO detection using a bioluminescent real time reporter (BART of loop mediated isothermal amplification (LAMP suitable for field use  

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Full Text Available Abstract Background There is an increasing need for quantitative technologies suitable for molecular detection in a variety of settings for applications including food traceability and monitoring of genetically modified (GM crops and their products through the food processing chain. Conventional molecular diagnostics utilising real-time polymerase chain reaction (RT-PCR and fluorescence-based determination of amplification require temperature cycling and relatively complex optics. In contrast, isothermal amplification coupled to a bioluminescent output produced in real-time (BART occurs at a constant temperature and only requires a simple light detection and integration device. Results Loop mediated isothermal amplification (LAMP shows robustness to sample-derived inhibitors. Here we show the applicability of coupled LAMP and BART reactions (LAMP-BART for determination of genetically modified (GM maize target DNA at low levels of contamination (0.1-5.0% GM using certified reference material, and compare this to RT-PCR. Results show that conventional DNA extraction methods developed for PCR may not be optimal for LAMP-BART quantification. Additionally, we demonstrate that LAMP is more tolerant to plant sample-derived inhibitors, and show this can be exploited to develop rapid extraction techniques suitable for simple field-based qualitative tests for GM status determination. We also assess the effect of total DNA assay load on LAMP-BART quantitation. Conclusions LAMP-BART is an effective and sensitive technique for GM detection with significant potential for quantification even at low levels of contamination and in samples derived from crops such as maize with a large genome size. The resilience of LAMP-BART to acidic polysaccharides makes it well suited to rapid sample preparation techniques and hence to both high throughput laboratory settings and to portable GM detection applications. The impact of the plant sample matrix and genome loading within a reaction must be controlled to ensure quantification at low target concentrations.

Kiddle Guy

2012-04-01

64

Creatures of Darkness: Bioluminescence  

Science.gov (United States)

In this activity students investigate bioluminescence, which is light given off by living organisms and is common among creatures of the sea. Students discover that in the deep sea, where little or no sunlight penetrates, a variety of fishes live out their lives dependent upon bioluminescence, and that among these fishes, light organs have evolved to serve a number of purposes. Students will learn about the function of bioluminescence among some marine animals and conduct an experiment to test the function of bioluminescence as camouflage. Included is background information, materials, procedures, and a follow-up evaluation.

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Insights into the kinetics of siRNA-mediated gene silencing from live-cell and live-animal bioluminescent imaging.  

Science.gov (United States)

Small interfering RNA (siRNA) molecules are potent effectors of post-transcriptional gene silencing. Using noninvasive bioluminescent imaging and a mathematical model of siRNA delivery and function, the effects of target-specific and treatment-specific parameters on siRNA-mediated gene silencing are monitored in cells stably expressing the firefly luciferase protein. In vitro, luciferase protein levels recover to pre-treatment values within return to steady-state levels in nondividing fibroblasts. Similar results are observed in vivo, with knockdown lasting approximately 10 days in subcutaneous tumors in A/J mice and 3-4 weeks in the nondividing hepatocytes of BALB/c mice. These data indicate that dilution due to cell division, and not intracellular siRNA half-life, governs the duration of gene silencing under these conditions. To demonstrate the practical use of the model in treatment design, model calculations are used to predict the dosing schedule required to maintain persistent silencing of target proteins with different half-lives in rapidly dividing or nondividing cells. The approach of bioluminescent imaging combined with mathematical modeling provides useful insights into siRNA function and may help expedite the translation of siRNA into clinically relevant therapeutics for disease treatment and management. PMID:16410612

Bartlett, Derek W; Davis, Mark E

2006-01-01

66

Influence of MSA on Cell Growth and Spontaneousn Metastasis of L9981-Luc Lung Cancer Transplanted Model in Nude Mice by Bioluminescence Imaging  

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Full Text Available Background and objective Methylseleninic acid (MSA is an artificially developed selenium compound. It has been proven that MSA could inhibit growth and metastasis on many tumor cells. This study investigated whether MSA has an impact on the growth and metastasis of L9981-Luc lung cancer transplanted model in nude mice or not. Methods A transplantated tumor model was established in nude mice. Fifteen nude mice were randomly divided into three groups: the control group treated with normal saline (0.2 mL/d, the MSA group treated with MSA solution (0.2 mL, and the cisplatin (DDP group injected intraperitoneally with DDP (4 mg/kg/w. Inhibition of MSA on tumor growth and tumor metastasis was observed using the IVIS Imaging System 200 Series. Results A significant difference was obserced in the primary tumor bioluminescence among the three groups (P=0.002 on 21 days post-inoculation. Primary tumor bioluminescence in the DDP group (P=0.001 and in the MSA group (P=0.031 was significantly lower than that in the control group (P=0.001. No significant difference in the metastasis bioluminescence of the thoracic area was indicated among the three groups (P>0.05. Conclusion MSA can inhibit the growth of planted tumor of transgenic lung cancer cell lines L9981-Luc in nude mice. MSA may also suppress the distant metastasis of the transplanted tumor of transgenic lung cancer cell lines L9981-Luc in nude mice.

Yuanrong REN

2013-02-01

67

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

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Full Text Available Abstract Background The bioluminescent enzyme firefly luciferase (Luc or variants of green fluorescent protein (GFP in transformed cells can be effectively used to reveal molecular and cellular features of neoplasia in vivo. Tumor cell growth and regression in response to various therapies can be evaluated by using bioluminescent imaging. In bioluminescent imaging, light propagates in highly scattering tissue, and the diffusion approximation is sufficiently accurate to predict the imaging signal around the biological tissue. The numerical solutions to the diffusion equation take large amounts of computational time, and the studies for its analytic solutions have attracted more attention in biomedical engineering applications. Methods Biological tissue is a turbid medium that both scatters and absorbs photons. An accurate model for the propagation of photons through tissue can be adopted from transport theory, and its diffusion approximation is applied to predict the imaging signal around the biological tissue. The solution to the diffusion equation is formulated by the convolution between its Green's function and source term. The formulation of photon diffusion from spherical bioluminescent sources in an infinite homogeneous medium can be obtained to accelerate the forward simulation of bioluminescent phenomena. Results The closed form solutions have been derived for the time-dependent diffusion equation and the steady-state diffusion equation with solid and hollow spherical sources in a homogeneous medium, respectively. Meanwhile, the relationship between solutions with a solid sphere source and ones with a surface sphere source is obtained. Conclusion We have formulated solutions for the diffusion equation with solid and hollow spherical sources in an infinite homogeneous medium. These solutions have been verified by Monte Carlo simulation for use in biomedical optical imaging studies. The closed form solution is highly accurate and more 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.

Wang Lihong V

2004-05-01

68

Luciferase expression and bioluminescence does not affect tumor cell growth in vitro or in vivo  

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Full Text Available Abstract Live animal imaging is becoming an increasingly common technique for accurate and quantitative assessment of tumor burden over time. Bioluminescence imaging systems rely on a bioluminescent signal from tumor cells, typically generated from expression of the firefly luciferase gene. However, previous reports have suggested that either a high level of luciferase or the resultant light reaction produced upon addition of D-luciferin substrate can have a negative influence on tumor cell growth. To address this issue, we designed an expression vector that allows simultaneous fluorescence and luminescence imaging. Using fluorescence activated cell sorting (FACS, we generated clonal cell populations from a human breast cancer (MCF-7 and a mouse melanoma (B16-F10 cell line that stably expressed different levels of luciferase. We then compared the growth capabilities of these clones in vitro by MTT proliferation assay and in vivo by bioluminescence imaging of tumor growth in live mice. Surprisingly, we found that neither the amount of luciferase nor biophotonic activity was sufficient to inhibit tumor cell growth, in vitro or in vivo. These results suggest that luciferase toxicity is not a necessary consideration when designing bioluminescence experiments, and therefore our approach can be used to rapidly generate high levels of luciferase expression for sensitive imaging experiments.

Rasko John EJ

2010-11-01

69

Bioluminescence in Plankton and Nekton  

Science.gov (United States)

This article, written by Peter J. Herring and Edith Widder of the International Society for Bioluminescence and Chemilumenescence, features an excerpt about bioluminescence from the Encyclopedia of Ocean Science. It includes an introduction to bioluminescence and the biochemistry behind it, information about bioluminescent organisms including a table of typical genera and their type of luminescence, a discussion of measurement and applications of bioluminescence, and resources for further reading.

Herring, Peter J.

70

Hydromechanical stimulation of bioluminescent plankton.  

Science.gov (United States)

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. PMID:12444590

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

2002-01-01

71

Stimulated bioluminescence by fluid shear stress associated with pipe flow  

Energy Technology Data Exchange (ETDEWEB)

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.

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

72

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.

73

Microbiological assay using bioluminescent organism  

Energy Technology Data Exchange (ETDEWEB)

This invention relates to testing processes for toxicity involving microorganisms and, more particularly, to testing processes for toxicity involving bioluminescent organisms. The present known method of testing oil-well drilling fluids for toxicity employs the mysid shrimp (Mysidopsis bahia) as the assay organism. The shrimp are difficult to raise and handle as laboratory assay organisms. This method is labor-intensive, because it requires a assay time of about 96 hours. Summary of the Invention: A microbiological assay in which the assay organism is the dinoflagellate, Pyrocystis lunula. A sample of a substance to be assayed is added to known numbers of the bioluminescent dinoflagellate and the mixture is agitated to subject the organisms to a shear stress causing them to emit light. The amount of light emitted is measured and compared with the amount of light emitted by a known non-toxic control mixture to determine if there is diminution or non-diminution of light emitted by the sample under test which is an indication of the presence or absence of toxicity, respectively. Accordingly, an object of the present invention is the provision of an improved method of testing substances for toxicity. A further object of the invention is the provision of an improved method of testing oil-well drilling fluids for toxicity using bioluminescent dinoflagellate (Pyrocystis lunula).

Stiffey, A.V.

1987-12-21

74

Multispectral Bioluminescence Tomography: Methodology and Simulation  

Directory of Open Access Journals (Sweden)

Full Text Available Bioluminescent imaging has proven to be a valuable tool for monitoring physiological and pathological activities at cellular and molecular levels in living small animals. Using biological techniques, target cells can be tagged with reporters encoding several kinds of luciferase enzymes, which generate characteristic photons in a wide spectrum covering the infrared range. Part of the diffused light can reach the body surface of the small animal, be separated into several spectral bands using appropriate filters, and collected by a sensitive CCD camera. Here we present a bioluminescence tomography (BLT method for a bioluminescent source reconstruction from multispectral data measured on the external surface, and demonstrate the advantages of multispectral BLT in a numerical study using a heterogeneous mouse chest phantom. The results show that the multispectral approach significantly improves the accuracy and stability of the BLT reconstruction even if the data are highly noisy.

Ge Wang

2006-02-01

75

An Advanced Preclinical Mouse Model for Acute Myeloid Leukemia Using Patients' Cells of Various Genetic Subgroups and In Vivo Bioluminescence Imaging  

Science.gov (United States)

Acute myeloid leukemia (AML) is a clinically and molecularly heterogeneous disease with poor outcome. Adequate model systems are required for preclinical studies to improve understanding of AML biology and to develop novel, rational treatment approaches. Xenografts in immunodeficient mice allow performing functional studies on patient-derived AML cells. We have established an improved model system that integrates serial retransplantation of patient-derived xenograft (PDX) cells in mice, genetic manipulation by lentiviral transduction, and essential quality controls by immunophenotyping and targeted resequencing of driver genes. 17/29 samples showed primary engraftment, 10/17 samples could be retransplanted and some of them allowed virtually indefinite serial transplantation. 5/6 samples were successfully transduced using lentiviruses. Neither serial transplantation nor genetic engineering markedly altered sample characteristics analyzed. Transgene expression was stable in PDX AML cells. Example given, recombinant luciferase enabled bioluminescence in vivo imaging and highly sensitive and reliable disease monitoring; imaging visualized minimal disease at 1 PDX cell in 10000 mouse bone marrow cells and facilitated quantifying leukemia initiating cells. We conclude that serial expansion, genetic engineering and imaging represent valuable tools to improve the individualized xenograft mouse model of AML. Prospectively, these advancements enable repetitive, clinically relevant studies on AML biology and preclinical treatment trials on genetically defined and heterogeneous subgroups. PMID:25793878

Vick, Binje; Rothenberg, Maja; Sandhöfer, Nadine; Carlet, Michela; Finkenzeller, Cornelia; Krupka, Christina; Grunert, Michaela; Trumpp, Andreas; Corbacioglu, Selim; Ebinger, Martin; André, Maya C.; Hiddemann, Wolfgang; Schneider, Stephanie; Subklewe, Marion; Metzeler, Klaus H.; Spiekermann, Karsten; Jeremias, Irmela

2015-01-01

76

Time encoded radiation imaging  

Science.gov (United States)

The various technologies presented herein relate to detecting nuclear material at a large stand-off distance. An imaging system is presented which can detect nuclear material by utilizing time encoded imaging relating to maximum and minimum radiation particle counts rates. The imaging system is integrated with a data acquisition system that can utilize variations in photon pulse shape to discriminate between neutron and gamma-ray interactions. Modulation in the detected neutron count rates as a function of the angular orientation of the detector due to attenuation of neighboring detectors is utilized to reconstruct the neutron source distribution over 360 degrees around the imaging system. Neutrons (e.g., fast neutrons) and/or gamma-rays are incident upon scintillation material in the imager, the photons generated by the scintillation material are converted to electrical energy from which the respective neutrons/gamma rays can be determined and, accordingly, a direction to, and the location of, a radiation source identified.

Marleau, Peter; Brubaker, Erik; Kiff, Scott

2014-10-21

77

Time-Encoded Imagers.  

Energy Technology Data Exchange (ETDEWEB)

This report provides a short overview of the DNN R&D funded project, Time-Encoded Imagers. The project began in FY11 and concluded in FY14. The Project Description below provides the overall motivation and objectives for the project as well as a summary of programmatic direction. It is followed by a short description of each task and the resulting deliverables.

Marleau, Peter; Brubaker, Erik

2014-11-01

78

A gantry-based tri-modality system for bioluminescence tomography  

OpenAIRE

A gantry-based tri-modality system that combines bioluminescence (BLT), diffuse optical (DOT), and x-ray computed tomography (XCT) into the same setting is presented here. The purpose of this system is to perform bioluminescence tomography using a multi-modality imaging approach. As parts of this hybrid system, XCT and DOT provide anatomical information and background optical property maps. This structural and functional a priori information is used to guide and restrain bioluminescence recon...

Yan, Han; Lin, Yuting; Barber, William C.; Unlu, Mehmet Burcin; Gulsen, Gultekin

2012-01-01

79

Bioluminescence-based visualization of CD4 T cell dynamics using a T lineage-specific luciferase transgenic model1  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Rapid clonal expansion of T cells occurs in response to antigenic challenges. The kinetics of the T cell response has previously been described using tissue-based studies performed at defined time points. Luciferase bioluminescence has recently been utilized for non-invasive analysis of in vivo biologic processes in real-time. Results We have created a novel transgenic mouse model (T-Lux using a human CD2 mini-gene to direct luciferase expression specifically to the T cell compartment. T-Lux T cells demonstrated normal homing patterns within the intact mouse and following adoptive transfer. Bioluminescent signal correlated with T cell numbers in the whole body images as well as within specific organ regions of interest. Following transfer into lymphopenic (RAG2-/- recipients, homeostatic proliferation of T-Lux T cells was visualized using bioluminescent imaging. Real-time bioluminescent analysis of CD4+ T cell antigen-specific responses enabled real-time comparison of the kinetics and magnitude of clonal expansion and contraction in the inductive lymph node and tissue site of antigen injection. T cell expansion was dose-dependent despite the presence of supraphysiologic numbers of OVA-specific OT-II transgenic TCR T-Lux T cells. CD4+ T cells subsequently underwent a rapid (3–4 day contraction phase in the draining lymph node, with a delayed contraction in the antigen delivery site, with bioluminescent signal diminished below initial levels, representing TCR clonal frequency control. Conclusion The T-Lux mouse provides a novel, efficient model for tracking in vivo aspects of the CD4+ T cell response to antigen, providing an attractive approach for studies directed at immunotherapy or vaccine design.

Zinn Kurt R

2009-08-01

80

Space-Time Quantum Imaging  

Directory of Open Access Journals (Sweden)

Full Text Available We report on an experimental and theoretical investigation of quantum imaging where the images are stored in both space and time. Ghost images of remote objects are produced with either one or two beams of chaotic laser light generated by a rotating ground glass and two sensors measuring the reference field and bucket field at different space-time points. We further observe that the ghost images translate depending on the time delay between the sensor measurements. The ghost imaging experiments are performed both with and without turbulence. A discussion of the physics of the space-time imaging is presented in terms of quantum nonlocal two-photon analysis to support the experimental results. The theoretical model includes certain phase factors of the rotating ground glass. These experiments demonstrated a means to investigate the time and space aspects of ghost imaging and showed that ghost imaging contains more information per measured photon than was previously recognized where multiple ghost images are stored within the same ghost imaging data sets. This suggests new pathways to explore quantum information stored not only in multi-photon coincidence information but also in time delayed multi-photon interference. The research is applicable to making enhanced space-time quantum images and videos of moving objects where the images are stored in both space and time.

Ronald E. Meyers

2015-03-01

81

Phage-amplified bioluminescent bioreporters for the detection of foodborne pathogens  

Science.gov (United States)

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.

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

2004-06-01

82

BRET3: a red-shifted bioluminescence resonance energy transfer (BRET)-based integrated platform for imaging protein-protein interactions from single live cells and living animals  

OpenAIRE

Taking advantage of the bioluminescence resonance energy transfer (BRET) phenomenon, we report the development of a highly photon-efficient, self-illuminating fusion protein combining a mutant red fluorescent protein (mOrange) and a mutant Renilla reniformis luciferase (RLuc8). This new BRET fusion protein (BRET3) exhibits severalfold improvement in light intensity in comparison with existing BRET fusion proteins. BRET3 also exhibits the most red-shifted light output (564-nm peak wavelength) ...

De, Abhijit; Ray, Pritha; Loening, Andreas Markus; Gambhir, Sanjiv Sam

2009-01-01

83

Real time ultrasound image denoising  

OpenAIRE

Image denoising is the process of removing the noise that perturbs image analysis methods. In some applications like segmentation or registration, denoising is intended to smooth homogeneous areas while preserving the contours. In many applications like video analysis, visual servoing or image-guided surgical interventions, real-time denoising is required. This paper presents a method for real-time denoising of ultrasound images: a modified version of the NL-means method is presented that inc...

Palhano Xavier Fontes, Fernanda; Andrade Barroso, Guillermo; Coupe?, Pierrick; Hellier, Pierre

2010-01-01

84

GMO detection using a bioluminescent real time reporter (BART) of loop mediated isothermal amplification (LAMP) suitable for field use  

OpenAIRE

Abstract Background There is an increasing need for quantitative technologies suitable for molecular detection in a variety of settings for applications including food traceability and monitoring of genetically modified (GM) crops and their products through the food processing chain. Conventional molecular diagnostics utilising real-time polymerase chain reaction (RT-PCR) and fluorescence-based determination of amplification require temperature cycling and relatively complex optics. In contra...

Kiddle Guy; Hardinge Patrick; Buttigieg Neil; Gandelman Olga; Pereira Clint; McElgunn Cathal J; Rizzoli Manuela; Jackson Rebecca; Appleton Nigel; Moore Cathy; Tisi Laurence C; Ah, Murray James

2012-01-01

85

Experimental Bioluminescence Tomography with Fully Parallel Radiative-transfer-based Reconstruction Framework  

OpenAIRE

Bioluminescence imaging is a very sensitive imaging modality, used in preclinical molecular imaging. However, in its planar projection form, it is non-quantitative and has poor spatial resolution. In contrast, bioluminescence tomography (BLT) promises to provide three dimensional quantitative source information. Currently, nearly all BLT reconstruction algorithms in use employ the diffusion approximation theory to determine light propagation in tissues. In this process, several approximations...

Lu, Yujie; Machado, Hidevaldo B.; Douraghy, Ali; Stout, David; Herschman, Harvey; Chatziioannou, Arion F.

2009-01-01

86

In vitro validation of bioluminescent monitoring of disease progression and therapeutic response in leukaemia model animals  

International Nuclear Information System (INIS)

The application of in vivo bioluminescence imaging to non-invasive, quantitative monitoring of tumour models relies on a positive correlation between the intensity of bioluminescence and the tumour burden. We conducted cell culture studies to investigate the relationship between bioluminescent signal intensity and viable cell numbers in murine leukaemia model cells. Interleukin-3 (IL-3)-dependent murine pro-B cell line Ba/F3 was transduced with firefly luciferase to generate cells expressing luciferase stably under the control of a retroviral long terminal repeat. The luciferase-expressing cells were transduced with p190 BCR-ABL to give factor-independent proliferation. The cells were cultured under various conditions, and bioluminescent signal intensity was compared with viable cell numbers and the cell cycle stage. The Ba/F3 cells showed autonomous growth as well as stable luciferase expression following transduction with both luciferase and p190 BCR-ABL, and in vivo bioluminescence imaging permitted external detection of these cells implanted into mice. The bioluminescence intensities tended to reflect cell proliferation and responses to imatinib in cell culture studies. However, the luminescence per viable cell was influenced by the IL-3 concentration in factor-dependent cells and by the stage of proliferation and imatinib concentration in factor-independent cells, thereby impairing the proportionality between viable cell number and bioluminescent signal intensitynumber and bioluminescent signal intensity. Luminescence per cell tended to vary in association with the fraction of proliferating cells. Although in vivo bioluminescence imaging would allow non-invasive monitoring of leukaemia model animals, environmental factors and therapeutic interventions may cause some discrepancies between tumour burden and bioluminescence intensity. (orig.)

87

Meshless local Petrov-Galerkin method for bioluminescent photon propagation in the biological tissue  

Science.gov (United States)

As a promising optical molecular imaging modality, bioluminescence tomography (BLT) has attracted remarkable attention for its excellent performance and high cost-effectiveness, which can be employed to specifically and directly reveal physiological and pathological activities in vivo at molecular and cellular levels. The goal of BLT is to reconstruct the internal bioluminescent light source with surface measurements. Therefore, the calculation of surface light exitance plays an important role in the inverse source reconstruction, whereas photon propagation is complicated because of strongly scattering property of the biological tissue. In this contribution, a novel meshless local Petrov-Galerkin (MLPG) method based on diffusion approximation model is developed to avoid the complex and time-consuming mesh division in the conventional finite element method (FEM), and MLPG requires only a series of discretized nodes without consideration of element information and node connectivity. Compared with other meshless methods based on global weak-form, background cells used for Gauss quadrature are also omitted in the proposed method. In addition, the tissue optical parameters are incorporated as a priori knowledge in this algorithm. Finally, the performance of this method is valuated using two- and three-dimensional numerical simulation experiments. The results demonstrate the effectiveness and feasibility of the presented algorithm to predict boundary bioluminescent light power distribution.

Qin, Chenghu; Tian, Jie; Yang, Xin; Liu, Kai; Feng, Jinchao; Xu, Min

2009-02-01

88

In vitro validation of bioluminescent monitoring of disease progression and therapeutic response in leukaemia model animals  

Energy Technology Data Exchange (ETDEWEB)

The application of in vivo bioluminescence imaging to non-invasive, quantitative monitoring of tumour models relies on a positive correlation between the intensity of bioluminescence and the tumour burden. We conducted cell culture studies to investigate the relationship between bioluminescent signal intensity and viable cell numbers in murine leukaemia model cells. Interleukin-3 (IL-3)-dependent murine pro-B cell line Ba/F3 was transduced with firefly luciferase to generate cells expressing luciferase stably under the control of a retroviral long terminal repeat. The luciferase-expressing cells were transduced with p190 BCR-ABL to give factor-independent proliferation. The cells were cultured under various conditions, and bioluminescent signal intensity was compared with viable cell numbers and the cell cycle stage. The Ba/F3 cells showed autonomous growth as well as stable luciferase expression following transduction with both luciferase and p190 BCR-ABL, and in vivo bioluminescence imaging permitted external detection of these cells implanted into mice. The bioluminescence intensities tended to reflect cell proliferation and responses to imatinib in cell culture studies. However, the luminescence per viable cell was influenced by the IL-3 concentration in factor-dependent cells and by the stage of proliferation and imatinib concentration in factor-independent cells, thereby impairing the proportionality between viable cell number and bioluminescent signal intensity. Luminescence per cell tended to vary in association with the fraction of proliferating cells. Although in vivo bioluminescence imaging would allow non-invasive monitoring of leukaemia model animals, environmental factors and therapeutic interventions may cause some discrepancies between tumour burden and bioluminescence intensity. (orig.)

Inoue, Yusuke; Okubo, Toshiyuki [University of Tokyo, Department of Radiology, Institute of Medical Science, Tokyo (Japan); Tojo, Arinobu; Sekine, Rieko; Soda, Yasushi; Kobayashi, Seiichiro; Nomura, Akiko; Izawa, Kiyoko [University of Tokyo, Division of Molecular Therapy, Advanced Clinical Research Centre, Tokyo (Japan); Kitamura, Toshio [University of Tokyo, Division of Cellular Therapy, Advanced Clinical Research Centre, Tokyo (Japan); Ohtomo, Kuni [University of Tokyo, Department of Radiology, Graduate School of Medicine, Tokyo (Japan)

2006-05-15

89

Bioluminescence tomography with CT/MRI co-registration.  

Science.gov (United States)

We present a three-dimensional (3D) bioluminescence image reconstruction method with MRI and CT co-registration for small animal molecular imaging. The multi-spectral light intensity distribution of an optical luciferase-luciferin reporter system is measured at the tissue surface of a small animal for the purpose of 3D image reconstruction. The reporter probe distribution inside tissue is calculated with a linear matrix inversion method and a light propagation model based on the simplified spherical harmonics equations. The animal's surface geometry and anatomy is determined from co-registered CT and MR images in order to locate the reconstructed source distribution relative to the animal's anatomy. We present in vivo bioluminescence reconstruction results that demonstrate the performance of our co-registration method. PMID:19964154

Klose, A D; Beattie, B J

2009-01-01

90

In vivo quantitative bioluminescence tomography using heterogeneous and homogeneous mouse models  

OpenAIRE

Bioluminescence tomography (BLT) is a new optical molecular imaging modality, which can monitor both physiological and pathological processes by using bioluminescent light-emitting probes in small living animal. Especially, this technology possesses great potential in drug development, early detection, and therapy monitoring in preclinical settings. In the present study, we developed a dual modality BLT prototype system with Micro-computed tomography (MicroCT) registration approach, and impro...

Liu, Junting; Wang, Yabin; Qu, Xiaochao; Li, Xiangsi; Ma, Xiaopeng; Han, Runqiang; Hu, Zhenhua; Chen, Xueli; Sun, Dongdong; Zhang, Rongqing; Chen, Duofang; Chen, Dan; Chen, Xiaoyuan; Liang, Jimin; Cao, Feng

2010-01-01

91

Automatic Segmentation Framework of Building Anatomical Mouse Model for Bioluminescence Tomography  

Directory of Open Access Journals (Sweden)

Full Text Available 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-ray computed tomography system and a multi-view bioluminescence imaging system. The findings suggest that the proposed method can realize fast automatic segmentation of mouse anatomical structures, ultimately enhancing the reconstruction performance of bioluminescence tomography.

Abdullah Alali

2013-09-01

92

A gantry-based tri-modality system for bioluminescence tomography  

Science.gov (United States)

A gantry-based tri-modality system that combines bioluminescence (BLT), diffuse optical (DOT), and x-ray computed tomography (XCT) into the same setting is presented here. The purpose of this system is to perform bioluminescence tomography using a multi-modality imaging approach. As parts of this hybrid system, XCT and DOT provide anatomical information and background optical property maps. This structural and functional a priori information is used to guide and restrain bioluminescence reconstruction algorithm and ultimately improve the BLT results. The performance of the combined system is evaluated using multi-modality phantoms. In particular, a cylindrical heterogeneous multi-modality phantom that contains regions with higher optical absorption and x-ray attenuation is constructed. We showed that a 1.5 mm diameter bioluminescence inclusion can be localized accurately with the functional a priori information while its source strength can be recovered more accurately using both structural and the functional a priori information. PMID:22559540

Yan, Han; Lin, Yuting; Barber, William C.; Unlu, Mehmet Burcin; Gulsen, Gultekin

2012-01-01

93

Bacterial Bioluminescence: Its Control and Ecological Significance  

Science.gov (United States)

This Microbiological Reviews scholarly article (23-page PDF) presents an overview of data relevant to the ecology of bioluminescent bacteria and the functional importance of light emission. The review article discusses the biochemistry of bioluminescence, taxonomic relationships of luminous bacteria, control of the synthesis and activity of the luminescent system, habitats and distribution of luminous bacteria, functions of bioluminescence, and new perspectives. These perspectives and other specific postulates presented in the article provide new approaches for data collection and experimental work.

Hastings, J. Woodland (John Woodland), 1927-

94

Molecular biology of bacterial bioluminescence.  

OpenAIRE

The cloning and expression of the lux genes from different luminescent bacteria including marine and terrestrial species have led to significant advances in our knowledge of the molecular biology of bacterial bioluminescence. All lux operons have a common gene organization of luxCDAB(F)E, with luxAB coding for luciferase and luxCDE coding for the fatty acid reductase complex responsible for synthesizing fatty aldehydes for the luminescence reaction, whereas significant differences exist in th...

Meighen, E. A.

1991-01-01

95

Discovery of a Bioluminescent Octopus  

Science.gov (United States)

Bioluminescence (light produced by a chemical reaction that originates from the organism) is common in deep sea creatures such as squids and cuttlefish, but it is very rare among octopods. Light organs have only been seen in breeding octopod females of two genera. The exciting discovery of bioluminescence in a deep-sea finned octopod, Stauroteuthis syrtensis, is the focus of this week's In the News. The blue-green light is emitted from the octopods' suckers, which have characteristics of both photophores and suckers. Lack of fossil records of bioluminescence has made it difficult to study the evolutionary history of light production. However, since these modified suckers have retained structural characteristics of their previous function (adhesive suckers), this offers a rare opportunity to view the evolutionary history of light production. Senior Scientist, Edith Widder, at the Harbor Branch Oceanographic Institution (HBOI) explains it as an example of an evolutionary transition, in the March 11th issue of Nature (1999, 398:113-114). Widder believes that the "change from sucker to light organ may have occurred during colonization of the deep open-ocean by a creature that was originally a shallow-water bottom-dweller." Furthermore, it is hypothesized that these modified suckers may now function to attract prey and to visually communicate. The six sites listed provide information about this discovery along with background information on bioluminescense and octopods.

Nannapaneni, Sujani.

1999-01-01

96

Preclinical evaluation of destruxin B as a novel Wnt signaling target suppressing proliferation and metastasis of colorectal cancer using non-invasive bioluminescence imaging  

Energy Technology Data Exchange (ETDEWEB)

In continuation to our studies toward the identification of direct anti-cancer targets, here we showed that destruxin B (DB) from Metarhizium anisopliae suppressed the proliferation and induced cell cycle arrest in human colorectal cancer (CRC) HT29, SW480 and HCT116 cells. Additionally, DB induced apoptosis in HT29 cells by decreased expression level of anti-apoptotic proteins Bcl-2 and Bcl-xL while increased pro-apoptotic Bax. On the other hand, DB attenuated Wnt-signaling by downregulation of ?-catenin, Tcf4 and ?-catenin/Tcf4 transcriptional activity, concomitantly with decreased expression of ?-catenin target genes cyclin D1, c-myc and survivin. Furthermore, DB affected the migratory and invasive ability of HT29 cells through suppressed MMPs-2 and -9 enzymatic activities. We also found that DB targeted the MAPK and/or PI3K/Akt pathway by reduced expression of Akt, IKK-?, JNK, NF-?B, c-Jun and c-Fos while increased that of I?B?. Finally, we demonstrated that DB inhibited tumorigenesis in HT29 xenograft mice using non-invasive bioluminescence technique. Consistently, tumor samples from DB-treated mice demonstrated suppressed expression of ?-catenin, cyclin D1, survivin, and endothelial marker CD31 while increased caspase-3 expression. Collectively, our data supports DB as an inhibitor of Wnt/?-catenin/Tcf signaling pathway that may be beneficial in the CRC management. Highlights: ? Destruxin B (DB) inhibited colorectal cancer cells growth and induced apoptosis. ? MAPK and/or PI3K/Akt cascade cooperates in DB induced apoptosis. ? DB affected the migratory and invasive ability of HT29 cells through MMP-9. ? DB attenuated Wnt-signaling components ?-catenin, Tcf4. ? DB attenuated cyclin D1, c-myc, survivin and tumorigenesis in HT29 xenograft mice.

Yeh, Chi-Tai [Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan (China); Center of Excellence for Cancer Research, Taipei Medical University, Taipei, Taiwan (China); Department of Surgery, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan (China); Rao, Yerra Koteswara [Institute of Biochemical Sciences and Technology, Chaoyang University of Technology, Taichung, Taiwan (China); Ye, Min [Department of Natural Medicine, School of Pharmaceutical Sciences, Peking University, Beijing (China); Wu, Wen-Shi [Department of Horticulture and Biotechnology, Chinese Culture University, Taipei, Taiwan (China); Chang, Tung-Chen [Department of Surgery, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan (China); Wang, Liang-Shun [Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Thoracic Surgery, Department of Surgery, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Wu, Chih-Hsiung [Center of Excellence for Cancer Research, Taipei Medical University, Taipei, Taiwan (China); Department of Surgery, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan (China); Wu, Alexander T.H., E-mail: chaw1211@tmu.edu.tw [Ph.D. Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan (China); Department of Radiation Oncology, Taipei Medical University Hospital, Taipei, Taiwan (China); Tzeng, Yew-Min, E-mail: ymtzeng@cyut.edu.tw [Institute of Biochemical Sciences and Technology, Chaoyang University of Technology, Taichung, Taiwan (China)

2012-05-15

97

Preclinical evaluation of destruxin B as a novel Wnt signaling target suppressing proliferation and metastasis of colorectal cancer using non-invasive bioluminescence imaging  

International Nuclear Information System (INIS)

In continuation to our studies toward the identification of direct anti-cancer targets, here we showed that destruxin B (DB) from Metarhizium anisopliae suppressed the proliferation and induced cell cycle arrest in human colorectal cancer (CRC) HT29, SW480 and HCT116 cells. Additionally, DB induced apoptosis in HT29 cells by decreased expression level of anti-apoptotic proteins Bcl-2 and Bcl-xL while increased pro-apoptotic Bax. On the other hand, DB attenuated Wnt-signaling by downregulation of ?-catenin, Tcf4 and ?-catenin/Tcf4 transcriptional activity, concomitantly with decreased expression of ?-catenin target genes cyclin D1, c-myc and survivin. Furthermore, DB affected the migratory and invasive ability of HT29 cells through suppressed MMPs-2 and -9 enzymatic activities. We also found that DB targeted the MAPK and/or PI3K/Akt pathway by reduced expression of Akt, IKK-?, JNK, NF-?B, c-Jun and c-Fos while increased that of I?B?. Finally, we demonstrated that DB inhibited tumorigenesis in HT29 xenograft mice using non-invasive bioluminescence technique. Consistently, tumor samples from DB-treated mice demonstrated suppressed expression of ?-catenin, cyclin D1, survivin, and endothelial marker CD31 while increased caspase-3 expression. Collectively, our data supports DB as an inhibitor of Wnt/?-catenin/Tcf signaling pathway that may be beneficial in the CRC management. Highlights: ? Destruxin B (DB) inhibited colorectal cancer cells growth and induced apoptosis. ? MAPK and/or PI3K/Akt cascade cooperates in DB induced apoptosis. ? DB affected the migratory and invasive ability of HT29 cells through MMP-9. ? DB attenuated Wnt-signaling components ?-catenin, Tcf4. ? DB attenuated cyclin D1, c-myc, survivin and tumorigenesis in HT29 xenograft mice.

98

Monsters of the Deep: Deep Sea Bioluminescence  

Science.gov (United States)

This award-winning Sea and Sky website uses creative graphics to explore deep sea bioluminescence. It defines the phenomenon of bioluminescence, explains the chemical reactions involved, describes organisms with this adaptation, and investigates possible reasons for this dazzling light show. Links direct users to similar pages about hydrothermal vents, ocean layers, and more.

J.D. Knight

99

Facile synthesis of gold-silver alloy nanoparticles for application in metal enhanced bioluminescence.  

Science.gov (United States)

In the present study we explored metal enhanced bioluminescence in luciferase enzymes for the first time. For this purpose a simple and reproducible one pot synthesis of gold-silver alloy nanoparticles was developed. By changing the molar ratio of tri-sodium citrate and silver nitrate we could synthesize spherical Au-Ag colloids of sizes ranging from 10 to 50 nm with a wide range of localized surface plasmon resonance (LSPR) peaks (450-550 nm). The optical tunability of the Au-Ag colloids enabled their effective use in enhancement of bioluminescence in a luminescent bacterium Photobacterium leiognathi and in luciferase enzyme systems from fireflies and bacteria. Enhancement of bioluminescence was 250% for bacterial cells, 95% for bacterial luciferase and 52% for firefly luciferase enzyme. The enhancement may be a result of energy transfer or plasmon induced enhancement. Such an increase can lead to higher sensitivity in detection of bioluminescent signals with potential applications in bio-analysis. PMID:24865663

Abhijith, K S; Sharma, Richa; Ranjan, Rajeev; Thakur, M S

2014-07-01

100

Bioluminescence tomography based on the phase approximation model  

OpenAIRE

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...

Cong, W.; Wang, G.

2010-01-01

101

Increased bioassay sensitivity of bioactive molecule discovery using metal-enhanced bioluminescence  

International Nuclear Information System (INIS)

We report the use of bioluminescence signal enhancement via proximity to deposited silver nanoparticles for bioactive compound discovery. This approach employs a whole-cell bioreporter harboring a plasmid-borne fusion of a specific promoter incorporated with a bioluminescence reporter gene. The silver deposition process was first optimized to provide optimal nanoparticle size in the reaction time dependence with fluorescein. The use of silver deposition of 350 nm particles enabled the doubling of the bioluminescent signal amplitude by the bacterial bioreporter when compared to an untouched non-silver-deposited microtiter plate surface. This recording is carried out in the less optimal but necessary far-field distance. SEM micrographs provided a visualization of the proximity of the bioreporter to the silver nanoparticles. The electromagnetic field distributions around the nanoparticles were simulated using Finite Difference Time Domain, further suggesting a re-excitation of non-chemically excited bioluminescence in addition to metal-enhanced bioluminescence. The possibility of an antiseptic silver effect caused by such a close proximity was eliminated disregarded by the dynamic growth curves of the bioreporter strains as seen using viability staining. As a highly attractive biotechnology tool, this silver deposition technique, coupled with whole-cell sensing, enables increased bioluminescence sensitivity, making it especially useful for cases in which reporter luminescence signals are very weak

102

Expanded palette of Nano-lanterns for real-time multicolor luminescence imaging  

Science.gov (United States)

Fluorescence live imaging has become an essential methodology in modern cell biology. However, fluorescence requires excitation light, which can sometimes cause potential problems, such as autofluorescence, phototoxicity, and photobleaching. Furthermore, combined with recent optogenetic tools, the light illumination can trigger their unintended activation. Because luminescence imaging does not require excitation light, it is a good candidate as an alternative imaging modality to circumvent these problems. The application of luminescence imaging, however, has been limited by the two drawbacks of existing luminescent protein probes, such as luciferases: namely, low brightness and poor color variants. Here, we report the development of bright cyan and orange luminescent proteins by extending our previous development of the bright yellowish-green luminescent protein Nano-lantern. The color change and the enhancement of brightness were both achieved by bioluminescence resonance energy transfer (BRET) from enhanced Renilla luciferase to a fluorescent protein. The brightness of these cyan and orange Nano-lanterns was ?20 times brighter than wild-type Renilla luciferase, which allowed us to perform multicolor live imaging of intracellular submicron structures. The rapid dynamics of endosomes and peroxisomes were visualized at around 1-s temporal resolution, and the slow dynamics of focal adhesions were continuously imaged for longer than a few hours without photobleaching or photodamage. In addition, we extended the application of these multicolor Nano-lanterns to simultaneous monitoring of multiple gene expression or Ca2+ dynamics in different cellular compartments in a single cell. PMID:25831507

Takai, Akira; Nakano, Masahiro; Saito, Kenta; Haruno, Remi; Watanabe, Tomonobu M.; Ohyanagi, Tatsuya; Jin, Takashi; Okada, Yasushi; Nagai, Takeharu

2015-01-01

103

Autofluorescence imaging device for real-time detection and tracking of pathogenic bacteria in a mouse skin wound model: preclinical feasibility studies  

Science.gov (United States)

Bacterial infection significantly impedes wound healing. Clinical diagnosis of wound infections is subjective and suboptimal, in part because bacteria are invisible to the naked eye during clinical examination. Moreover, bacterial infection can be present in asymptomatic patients, leading to missed opportunities for diagnosis and treatment. We developed a prototype handheld autofluorescence (AF) imaging device (Portable Real-time Optical Detection, Identification and Guidance for Intervention-PRODIGI) to noninvasively visualize and measure bacterial load in wounds in real time. We conducted preclinical pilot studies in an established nude mouse skin wound model inoculated with bioluminescent Staphylococcus aureus bacteria. We tested the feasibility of longitudinal AF imaging for in vivo visualization of bacterial load in skin wounds, validated by bioluminescence imaging. We showed that bacteria (S. aureus), occult to standard examination, can be visualized in wounds using PRODIGI. We also detected quantitative changes in wound bacterial load over time based on the antibiotic treatment and the correlation of bacterial AF intensity with bacterial load. AF imaging of wounds offers a safe, noninvasive method for visualizing the presence, location, and extent of bacteria as well as measuring relative changes in bacterial load in wounds in real time.

Wu, Yichao Charlie; Kulbatski, Iris; Medeiros, Philip J.; Maeda, Azusa; Bu, Jiachuan; Xu, Lizhen; Chen, Yonghong; DaCosta, Ralph S.

2014-08-01

104

Experimental Study on Bioluminescence Tomography with Multimodality Fusion  

Directory of Open Access Journals (Sweden)

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.

Yujie Lv

2007-09-01

105

Shedding Light on the Bioluminescence "Paradox"  

Science.gov (United States)

This ASM News article explores biochemistry, genetics, and cell density-dependent regulation of bacterial bioluminescence, addressing the question: What good is it to bioluminescent bacteria? The article reviews the symbiosis between the bioluminescent bacterium Vibrio fischeri and the Hawaiian bobtail squid, and examines how progress in understanding the genetics of V. fischeri, including genomic sequencing of a squid symbiont, is enabling researchers to analyze how luminescence integrates with the physiology of this bacterial species. The article includes a link to a detailed author profile.

Eric V. Stabb

106

A fast dynamic linked library based mixed-language programming technology for the trust region method in bioluminescence tomography  

Science.gov (United States)

Bioluminescence tomography (BLT) is a novel optical molecular imaging (MI) modality. It can reconstruct the inner bioluminescent light source distribution, according to the surface light distribution. The trust region method (TRM) can overcome the ill-posedness of BLT for its regularization property. As there exists a "TRUST" function that can solve the trust region subproblem in Matlab and Matlab's powerful matrix operation ability suited for TRM, the TRM is implemented in Matlab. Then the Matlab code of TRM is transformed into a dynamic linked library (DDL) and mixed together with the C++ code of the adaptive finite element (AFE) framework, using the mixed-language programming technology (MLPT). There are two main advantages of the MLPT. The first is taking advantages of all the participated programming languages. The second is time efficient. The usual way of transferring data between programmes written in different programming languages is to write the data first into files that are stored in the hard discs in one programme, and then read the files from another programme. Besides wasting time on writing and reading, it is difficult to keep the precision of the data. The DLL based MLPT can eliminate the need of installing code compilers in the platform running the software. Furthermore, in DLL, the code is implemented in C/C++ with high time efficiency, while the code in Matlab remains relatively low time efficiency. Finally, a numerical experiment is carried out to show MLPT's usage in the source reconstruction procedure of BLT, using the MLPT based on DLL.

Zhang, Bo; Tian, Jie; Yang, Xin; Qin, Chenghu; Han, Dong; Ma, Xibo

2011-03-01

107

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

OpenAIRE

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 we developed before, is employed here. Result shows that BP is an effective method to position the light source.

Zhun Xu; Xiaolei Song; Xiaomeng Zhang; Jing Bai

2007-01-01

108

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

Science.gov (United States)

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.

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

2014-01-01

109

Sensitive in vivo imaging of T cells using a membrane-bound Gaussia princeps luciferase.  

Science.gov (United States)

We developed a new approach to bioluminescent T cell imaging using a membrane-anchored form of the Gaussia luciferase (GLuc) enzyme, termed extGLuc, which we could stably express in both mouse and human primary T cells. In vitro, extGLuc+ cells emitted significantly higher bioluminescent signal when compared to cells expressing GLuc, Renilla luciferase (RLuc) or membrane-anchored RLuc (extRLuc). In vivo, mouse extGLuc+ T cells showed higher bioluminescent signal when compared to GLuc+ and RLuc+ T cells. Application of this imaging approach to human T cells genetically modified to express tumor-specific chimeric antigen receptors (CARs) enabled us to show in vivo CAR-mediated T cell accumulation in tumor, T cell persistence over time and concomitant imaging of T cells and tumor cells modified to express firefly luciferase. This sensitive imaging technology has application to many in vivo cell-based studies in a wide array of mouse models. PMID:19219023

Santos, Elmer B; Yeh, Raymond; Lee, James; Nikhamin, Yan; Punzalan, Blesida; Punzalan, Blesserene; La Perle, Krista; Larson, Steven M; Sadelain, Michel; Brentjens, Renier J

2009-03-01

110

Image processing in real time radiography  

International Nuclear Information System (INIS)

Image processing in real time radiography has become an important feature to improve the detectibility of defects. However, often enough, impressed by the tremendous success of image processing of e.g. evaluation of Landsat pictures, people expect the same or nearly the same effect in NDT applications. The magic word image processing thus results in unrealistic demands to the capability even of highly sophisticated image processing systems. In this paper the possibilities as well as the different tasks of image processing in the field of real time radiography is discussed

111

Generation of a new bioluminescent model for visualisation of mammary tumour development in transgenic mice  

LENUS (Irish Health Repository)

AbstractBackgroundNumerous transgenic models have been generated to study breast cancer. However, despite many advantages, traditional transgenic models for breast cancer are also burdened with difficulties in early detection and longitudinal observation of transgene-induced tumours, which in most cases are randomly located and occur at various time points. Methods such as palpation followed by mechanical measurement of the tumours are of limited value in transgenic models. There is a crucial need for making these previously generated models suitable for modern methods of tumour visualisation and monitoring, e.g. by bioluminescence-based techniques. This approach was successfully used in the current study.ResultsA new mouse strain (MMTV-Luc2 mice) expressing Luc2 luciferase primarily in mammary tissue in females, with low-level background expression in internal organs, was generated and bred to homozygosity. After these mice were intercrossed with MMTV-PyVT mice, all double transgenic females developed mammary tumours by the age of 10?weeks, the localisation and progression of which could be effectively monitored using the luminescence-based in vivo imaging. Luminescence-based readout allowed for early visualisation of the locally overgrown mammary tissue and for longitudinal evaluation of local progression of the tumours. When sampled ex vivo at the age of 10?weeks, all tumours derived from MMTV-Luc2PyVT females displayed robust bioluminescent signal.ConclusionsWe have created a novel transgenic strain for visualisation and longitudinal monitoring of mammary tumour development in transgenic mice as an addition and\\/or a new and more advanced alternative to manual methods. Generation of this mouse strain is vital for making many of the existing mammary tumour transgenic models applicable for in vivo imaging techniques.

Zagozdzon, Agnieszka M

2012-05-30

112

Immobilized Bioluminescent Reagents in Flow Injection Analysis.  

Science.gov (United States)

Available from UMI in association with The British Library. Bioluminescent reactions exhibits two important characteristics from an analytical viewpoint; they are selective and highly sensitive. Furthermore, bioluminescent emissions are easily measured with a simple flow-through detector based on a photomultiplier tube and the rapid and reproducible mixing of sample and expensive reagent is best achieved by a flow injection manifold. The two most important bioluminescent systems are the enzyme (luciferase)/substrate (luciferin) combinations extracted from fireflies (Photinus pyralis) and marine bacteria (Virio harveyi) which requires ATP and NAD(P)H respectively as cofactors. Reactions that generate or consume these cofactors can also be coupled to the bioluminescent reaction to provide assays for a wide range of clinically important species. A flow injection manifold for the study of bioluminescent reactions is described, as are procedures for the extraction, purification and immobilization of firefly and bacterial luciferase and oxidoreductase. Results are presented for the determination of ATP using firefly system and the determination of other enzymes and substrates participating in ATP-converting reactions e.g. creatine kinase, ATP-sulphurylase, pyruvate kinase, creatine phosphate, pyrophosphate and phophoenolypyruvate. Similarly results are presented for the determination of NAD(P)H, FMN, FMNH_2 and several dehydrogenases which produce NAD(P)H and their substrates, e.g. alcohol, L-lactate, L-malate, L-glutamate, Glucose-6-phosphate and primary bile acid.

Nabi, Abdul

113

Positive self-image over time  

OpenAIRE

This paper incorporates egocentric comparisons into a human capital accumulation model and studies the evolution of positive self image over time. The paper shows that the process of human capital accumulation together with egocentric comparisons imply that positive self image of a cohort is first increasing and then decreasing over time. Additionally, the paper finds that positive self image: (1) peaks earlier in activities where skill depreciation is higher, (2) is smaller in activities ...

Santos-pinto, Lui?s

2005-01-01

114

Bioluminescent bioreporter assays for targeted detection of chemical and biological agents  

Science.gov (United States)

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.

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

2008-04-01

115

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)

116

Chemistry and biology of insect bioluminescence  

Energy Technology Data Exchange (ETDEWEB)

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.

Colepicolo Neto, P.; Bechara, E.J.H. (Sao Paulo Univ. (Brazil). Inst. de Quimica)

1984-12-01

117

Sparsity reconstruction for bioluminescence tomography based on an augmented Lagrangian method  

Science.gov (United States)

Bioluminescence imaging (BLI) is an optical molecular imaging modality for monitoring physiological and pathological activities at the molecular level. The information of bioluminescent probe distribution in small animals can be threedimensionally and quantitatively obtained by bioluminescence tomography (BLT). Due to ill-posed nature, BLT may bear multiple solutions and aberrant reconstruction in the presence of measurement noise and optical parameter mismatches. Among different regularization methods, L2-type regularization strategy is the most popular and commonly-applied method, which minimizes the output-least-square formulation incorporated with the l2-norm regularization term to stabilize the problem. However, it often imposes over-smoothing on the reconstruction results. In contrast, for many practical applications, such as early detection of tumors, the volumes of the bioluminescent sources are very small compared with the whole body. In this paper, L1 regularization is used to fully take advantage of the sparsity prior knowledge and improve both efficiency and stability. And then a reconstruction method based on the augmented Lagrangian approach is proposed, which considers the BLT problem as the constrained optimization problem and employs the Bregman iterative method to deal with it. By using "divide and conquer" approach, the optimization problem can be exactly and fast solved by iteratively solving a sequence of unconstrained subproblems. To evaluate the performance of the proposed method in turbid mouse geometry, stimulate experiments with a heterogeneous 3D mouse atlas are conducted. In addition, physical experiments further demonstrate the potential of the proposed algorithm in practical applications.

Guo, Wei; Jia, Kebin; Tian, Jie; Han, Dong; Liu, Xueyan; Liu, Kai; Zhang, Qian; Feng, Jinchao; Qin, Chenghu

2012-03-01

118

Adaptive row-action inverse solver for fast noise-robust three-dimensional reconstructions in bioluminescence tomography: theory and dual-modality optical/computed tomography in vivo studies.  

Science.gov (United States)

A novel approach is presented for obtaining fast robust three-dimensional (3-D) reconstructions of bioluminescent reporters buried deep inside animal subjects from multispectral images of surface bioluminescent photon densities. The proposed method iteratively acts upon the equations relating the multispectral data to the luminescent distribution with high computational efficiency to provide robust 3-D reconstructions. Unlike existing algebraic reconstruction techniques, the proposed method is designed to use adaptive projections that iteratively guide the updates to the solution with improved speed and robustness. Contrary to least-squares reconstruction methods, the proposed technique does not require parameter selection or optimization for optimal performance. Additionally, optimized schemes for thresholding, sampling, and ordering of the bioluminescence tomographic data used by the proposed method are presented. The performance of the proposed approach in reconstructing the shape, volume, flux, and depth of luminescent inclusions is evaluated in a multitude of phantom-based and dual-modality in vivo studies in which calibrated sources are implanted in animal subjects and imaged in a dual-modality optical/computed tomography platform. Statistical analysis of the errors in the depth and flux of the reconstructed inclusions and the convergence time of the proposed method is used to demonstrate its unbiased performance, low error variance, and computational efficiency. PMID:23843087

Behrooz, Ali; Kuo, Chaincy; Xu, Heng; Rice, Brad

2013-07-01

119

Real-Time Imaging of Quantum Entanglement  

OpenAIRE

Quantum Entanglement is widely regarded as one of the most prominent features of quantum mechanics and quantum information science. Although, photonic entanglement is routinely studied in many experiments nowadays, its signature has been out of the grasp for real-time imaging. Here we show that modern technology, namely triggered intensified charge coupled device (ICCD) cameras are fast and sensitive enough to image in real-time the effect of the measurement of one photon on...

Robert Fickler; Mario Krenn; Radek Lapkiewicz; Sven Ramelow; Anton Zeilinger

2013-01-01

120

Enhanced Landweber algorithm via Bregman iterations for bioluminescence tomography  

Science.gov (United States)

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.

Xia, Yi; Zhang, Meng

2014-09-01

121

4D multimodality imaging of Citrobacter rodentium infections in mice.  

Science.gov (United States)

This protocol outlines the steps required to longitudinally monitor a bioluminescent bacterial infection using composite 3D diffuse light imaging tomography with integrated ?CT (DLIT-?CT) and the subsequent use of this data to generate a four dimensional (4D) movie of the infection cycle. To develop the 4D infection movies and to validate the DLIT-?CT imaging for bacterial infection studies using an IVIS Spectrum CT, we used infection with bioluminescent C. rodentium, which causes self-limiting colitis in mice. In this protocol, we outline the infection of mice with bioluminescent C. rodentium and non-invasive monitoring of colonization by daily DLIT-?CT imaging and bacterial enumeration from feces for 8 days. The use of the IVIS Spectrum CT facilitates seamless co-registration of optical and ?CT scans using a single imaging platform. The low dose ?CT modality enables the imaging of mice at multiple time points during infection, providing detailed anatomical localization of bioluminescent bacterial foci in 3D without causing artifacts from the cumulative radiation. Importantly, the 4D movies of infected mice provide a powerful analytical tool to monitor bacterial colonization dynamics in vivo. PMID:23979310

Collins, James William; Meganck, Jeffrey A; Kuo, Chaincy; Francis, Kevin P; Frankel, Gad

2013-01-01

122

Real-time imaging detectors for portal imaging  

International Nuclear Information System (INIS)

This paper reviews the status of real-time imaging systems which are used in radiation-therapy for radiotherapy localization and verification. Imaging systems under review include (1) metal-fluorescent screens, optically coupled to video cameras, (2) metal-phosphor screen in direct contact with two-dimensional photo-diode array (flat panel detector), (3) two-dimensional liquid ionization chamber and (5) linear diode arrays. These systems permit frequent verification during the treatment and have been shown to be very useful. Unfortunately the image quality achieved, while impressive considering the short time the devices have been on the market, is significantly inferior to that which is available form the metal/film combination (port film). The spatial resolution is about 1 lp/mm at 10% MTF, the Detective Quantum Efficiency (DQE) is less than 1% at 0 lp/mm and less than 0.1% at 1 lp/mm. It is also noted that these systems have not reached their ultimate limits of performance yet. The levels of x-ray fluence in the radiotherapy beam should allow a significant increase in the image quality. Nevertheless, the digital imaging systems available now are superior to analog film based systems because they provide a separation between the important functions of detection and display. They can provide almost instant image processing to optimize the information to be presented to the human observer. 100 refs., 11 figs., 4 tabs

123

Construction of a Bioluminescent Reporter Strain To Detect Polychlorinated Biphenyls  

OpenAIRE

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...

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

1998-01-01

124

Salmonella typhimurium infections in BALB/c mice: a comparison of tissue bioluminescence, tissue cultures and mice clinical scores.  

Science.gov (United States)

In response to systemic infection, mice usually present specific behaviors such as reduced activity and feeding, ruffled fur, hunched position, ataxia and tremor. We aimed to compare tissue bioluminescence, tissue cultures and clinical scores of BALB/c mice as potentially complementary outcome measures of Salmonella disease progression In Balb/c mice. The clinical status of the mice was assessed by visual examination for motility, ruffled fur, hunched position, feeding, ataxia and tremor. Patterns of bioluminescent light emission indicated the progression of infection from the abdominal region (initial site) to secondary tissue sites, which was indicative of systemic infection. As the severity and progression of infection increased, the bioluminescence signal became both more prominent and more anatomically disseminated. Bioluminescent Imaging (BLI) of Salmonella that have been genetically engineered to be bioluminescent is a new method that gives the opportunity to track Salmonella dissemination in mice. BLI is a helpful method to estimate tissue Salmonella concentration and may reduce the number of mice used in experiments, providing the opportunity to obtain serial assessments of disease progression in a single mouse subject. Clinical scores helped us to assess the clinical status of BALB/c mice in systemic Salmonella infections. PMID:22378553

Özkaya, Halit; Akcan, Abdullah Baris; Aydemir, Gökhan; Aydinöz, Secil; Razia, Yasmin; Gammon, S T; McKinney, Jeff

2012-01-01

125

Influence of the temperature at the Black Sea ctenophores-aliens bioluminescence characteristics  

Directory of Open Access Journals (Sweden)

Full Text Available Successful invasion of Mnemiopsis leidyi A. Agassiz, 1865 and Beroe ovata Mayer, 1912 into the Black Sea and their important role in this region pelagic ecosystem is stipulated mainly by the considerable eurythermy of these species. Many ecological-physiological characteristics of ctenophores—aliens are studied quite well. However, bioluminescence, one of the most important elements of the ctenophores ecology and the bioluminescence reaction temperature optimum for these individuals under different environment temperatures were not studied sufficiently. Therefore our researches in this scientific field are significant and conceptually novel for ctenophores ecology study. Experimental investigations were carried out in the period of 2008-2009 in the IBSS. Uni-sized (40 mm ctenophores were collected in the Sevastopol coastal zone and divided in several groups, contained under different temperatures: from 10°C ± 1°C to 30°C ± 1°C. Ctenophore bioluminescence was investigated under chemical and mechanical stimulation. M. leidyi light emission maximal amplitude (1432.94 ± 71.64 × 108 quantum·s–1·cm–2 with duration of 3.54 ± 0.15 s is fixed under the temperature of 26°C ± 1°C. Temperature increase up to 30°C ± 1°C led to the 4 times decrease of the bioluminescence intensity. Under temperature decrease up to 10°C ± 1°C this parameter decreased 20 times (p < 0.05. Bioluminescence emission intensity characteristics of B. ovata achieved maximal values under the temperature of 22°C ± 1°C (1150.12 ± 57.51 × 108 quantum·s–1·cm–2 with duration of 3.03 ± 0.15 s. The luminescence intensity decreased under the temperature increase to 30°C ± 1°C more than 20 times. Temperature decrease to the values of 10°C ± 1°C impacted decreasing the amplitude of bioluminescence up to the minimal –4.92 ± 0.22 × 108 quantum·s–1·cm–2. The data obtained testify that characteristics of the ctenophores bioluminescence can be conditioned not only by the modification the environment temperature but by the variability of their physiological condition.

Tokarev Yuriy

2012-06-01

126

Molecular imaging of nuclear factor-Y transcriptional activity maps proliferation sites in live animals  

OpenAIRE

The activity of the nuclear factor-Y (NF-Y) transcription factor is restricted to proliferating cells in vitro. We engineered transgenic mice that enabled bioluminescence imaging of NF-Y activity in every area of the body. We visualized areas of proliferation, and we highlight for the first time a role of NF-Y activity in hepatocyte proliferation during liver regeneration.

Ramachandran, Balaji; Rando, Gianpaolo; Maggi, Adriana Caterina; Ciana, Paolo

2012-01-01

127

Transformation Experiment Using Bioluminescence Genes of "Vibrio fischeri."  

Science.gov (United States)

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)

Slock, James

1995-01-01

128

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

Science.gov (United States)

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. PMID:25329534

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

2014-01-01

129

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

Directory of Open Access Journals (Sweden)

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.

Andrea Osimani

2014-10-01

130

Actual imaging time in fetal MRI  

International Nuclear Information System (INIS)

Objective: Safety issues in magnetic resonance imaging (MRI) are important, especially in fetal MRI. However, since basic data with respect of the effective exposure time in fetal MRI are not available, this study aimed to determine the actual imaging time during a fetal MRI study. Methods: 100 fetal MRI studies of singleton pregnancies performed on a 1.5 T system were analysed with respect to study duration (from starting the survey scan until the end of study), the number of sequences acquired, and the actual imaging time, which was calculated by adding up scan time of each sequence. Furthermore, each sequence type was analysed regarding the number of acquisitions, specific absorption rates (SAR), and duration. Results: Mean study duration was 34.6 min (range: 14–58 min; standard deviation (SD): 9.7 min), the average number of sequences acquired was 26.6 (range: 11–44, SD: 6.6). Actual scan time averaged 11.4 min (range: 4–19 min, SD: 4.0 min). Ultrafast T2-weighted and steady-state free-precession sequences accounted for 62.3% of actual scan time, and were distributed over the whole duration of the study. Conclusion: Actual imaging time only accounts for 33% of total study time and is not continuous. The remaining time is consumed by the preparation phases of the scanner, and is spent with planning sequences and the eventual repositioning of the coil and/or pregnant woman. These data may help to more accurately estimate the exposure to radiofrequency depositi exposure to radiofrequency deposition and noise during fetal MRI studies.

131

Dual monitoring using 124I-FIAU and bioluminescence for HSV1-tk suicide gene therapy  

International Nuclear Information System (INIS)

Herpes simplex virus type I thymidine kinase (HSV-tk) is the most common reporter gene and is used in cancer gene therapy with a prodrug nucleoside analog, ganciclovir (GCV). The aim of this study is to evaluate therapeutic efficacy of suicide gene therapy with 2'-fluoro-2'-deoxy-1-D-arabinofuranosyl-5-[124I] iodouracil (124I - FIAU) and bioluminescence in retrovirally HSV -tk and firefly luciferase transduced hepatoma model. The HSV -tk and firefly luciferase (Luc) was retrovirally transduced and expressed in MCA rat Morris hepatoma cells. Nude mice with subcutaneous tumors, MCA and MCA-TK-Luc, were subjected to GCV treatment (50mg/Kg/d intraperitoneally) for 5 day. PET imaging and biodistribution with (124I-FIAU) were performed at before and after initiation of therapy with GCV. Bioluminescent signal was also measured during GCV treatment. Before GCV treatment, no significant difference in tumor volume was found in tumors between MCA and MCA-TK-Luc. After GCV treatment, tumor volume of MCA-TK-Luc markedly reduced compared to that of MCA. In biodistribution study, 124I-FIAU uptake after GCV therapy significantly decreased compared with pretreatment levels (34.8 13.67 %ID/g vs 7.6 2.59 %ID/g) and bioluminescent signal was also significantly decreased compared with pretreatment levels. In small animal PET imaging, 124I-FIAU selectively localized in HSV -tk expressing tumor and the therapeutic efficacy of GCV treatmand the therapeutic efficacy of GCV treatment was evaluated by 124I-FIAU PET imaging. 124I-FIAU PET and bioluminescence imaging in HSV-tk suicide gene therapy were effective to evaluate the therapeutic response. 124I-FIAU may serve as an efficient and selective agent for monitoring of transduced HSV1-tk gene expression in vivo in clinical trials

132

Real-time image and video processing  

CERN Document Server

This book presents an overview of the guidelines and strategies for transitioning an image or video processing algorithm from a research environment into a real-time constrained environment. Such guidelines and strategies are scattered in the literature of various disciplines including image processing, computer engineering, and software engineering, and thus have not previously appeared in one place. By bringing these strategies into one place, the book is intended to serve the greater community of researchers, practicing engineers, industrial professionals, who are interested in taking an im

Kehtarnavaz, Nasser

2006-01-01

133

Detection of ATP and NADH: A Bioluminescent Experience.  

Science.gov (United States)

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,…

Selig, Ted C.; And Others

1984-01-01

134

Ultrasensitive detection of cellular protein interactions using bioluminescence resonance energy transfer quantum dot-based nanoprobes.  

Science.gov (United States)

Sensitive detection of protein interactions is a critical step toward understanding complex cellular processes. As an alternative to fluorescence-based detection, Renilla reniformis luciferase conjugated to quantum dots results in self-illuminating bioluminescence resonance energy transfer quantum dot (BRET-Qdot) nanoprobes that emit red to near-infrared bioluminescence light. Here, we report the development of an ultrasensitive technology based on BRET-Qdot conjugates modified with streptavidin ([BRET-Qdot]-SA) to detect cell-surface protein interactions. Transfected COS7 cells expressing human cell-surface proteins were interrogated with a human Fc tagged protein of interest. Specific protein interactions were detected using a biotinylated anti-human Fc region specific antibody followed by incubation with [BRET-Qdot]-SA. The luciferase substrate coelenterazine activated bioluminescence light emission was detected with an ultra-fast and -sensitive imager. Protein interactions barely detectable by the fluorescence-based approach were readily quantified using this technology. The results demonstrate the successful application and the flexibility of the BRET-Qdot-based imaging technology to the ultrasensitive investigation of cell-surface proteins and protein-protein interactions. PMID:22573556

Quiñones, Gabriel A; Miller, Steven C; Bhattacharyya, Sukanta; Sobek, Daniel; Stephan, Jean-Philippe

2012-07-01

135

Dinoflagellate bioluminescence in response to mechanical stimuli in water flows  

Directory of Open Access Journals (Sweden)

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.

A. S. Cussatlegras

2005-01-01

136

NDE Imaging of Time Differential Terahertz Waves  

Science.gov (United States)

Natural voids are present in the vicinity of a conathane interface that bonds two different foam materials. These voids are out of focus with the terahertz imaging system and multiple optical reflections also make it difficult to determine their depths. However, waves passing through the top foam article at normal incidence are partially reflected at the denser conathane layer prior to total reflection at the tank s wall. Reflections embedded in the oscillating noise segment prior to the main signals can be extracted with dual applications of filtering and time derivative. Void's depth is computed from direct path's time of flight.

Trinh, Long B.

2008-01-01

137

Interactive Real-time Magnetic Resonance Imaging  

DEFF Research Database (Denmark)

Real-time acquisition, reconstruction and interactively changing the slice position using magnetic resonance imaging (MRI) have been possible for years. However, the current clinical use of interactive real-time MRI is limited due to an inherent low spatial and temporal resolution. This PhD project seeks to implement and assess existing reconstruction algorithms using multi-processors of modern graphics cards and many-core computer processors and to cover some of the potential clinical applications which might benefit from using an interactive real-time MRI system. First an off-line, but interactive, slice alignment tool was used to support the notion that 3D blood flow quantification in the heart possesses the ability to obtain curves and volumes which are not statistical different from standard 2D flow. Secondly, the feasibility of an interactive real-time MRI system was exploited with regard to optimal sampling strategy for detecting motion in four different anatomies on two different MRI scanner brands. A fully implemented interactive real-time MRI system was exploited in a group of healthy fetuses and proved its eligibility as an alternative diagnostic tool for fetal imaging. Finally, the system was used for 3D motion tracking of the liver, and its use was proposed for future integrations of MRI scanners and linear accelerators in the field of radiotherapy treatment.

Brix, Lau

2013-01-01

138

Real-time evaluation of two light delivery systems for photodynamic disinfection of Candida albicans biofilm in curved root canals.  

Science.gov (United States)

Antimicrobial photodynamic therapy (APDT) combined with endodontic treatment has been recognized as an alternative approach to complement conventional root canal disinfection methods on bacterial biofilms. We developed an in  vitro model of bioluminescent Candida albicans biofilm inside curved dental root canals and investigated the microbial reduction produced when different light delivery methods are employed. Each light delivery method was evaluated in respect to the light distribution provided inside curved root canals. After conventional endodontic preparation, teeth were sterilized before canals were contaminated by a bioluminescent strain of C. albicans (CEC789). Methylene blue (90 ?M) was introduced into the canals and then irradiated (??=?660 nm, P?=?100 mW, beam diameter?=?2 mm) with laser tip either in contact with pulp chamber or within the canal using an optical diffuser fiber. Light distribution was evaluated by CCD camera, and microbial reduction was monitored through bioluminescence imaging. Our findings demonstrated that the bioluminescent C. albicans biofilm model had good reproducibility and uniformity. Light distribution in dental tissue was markedly dependent on the light delivery system, and this strategy was directly related to microbial destruction. Both light delivery systems performed significant fungal inactivation. However, when irradiation was performed with optical diffuser fiber, microbial burden reduction was nearly 100 times more effective. Bioluminescence is an interesting real-time analysis to endodontic C. albicans biofilm inactivation. APDT showed to be an effective way to inactivate C. albicans biofilms. Diffuser fibers provided optimized light distribution inside curved root canals and significantly increased APDT efficiency. PMID:25060900

Sabino, C P; Garcez, A S; Núñez, S C; Ribeiro, M S; Hamblin, M R

2014-07-25

139

Chemiluminescence and bioluminescence past, present and future  

CERN Document Server

This complete and well-organized overview of chemiluminescence and bioluminescence is divided into two parts. The first covers historical developments and the fundamental principles of these phenomena before going on to review recent advances and instrumentation. The second part deals with the applications in a variety of research fields including life sciences, drug discovery, diagnostics, environment, agrofood, and forensics. The book is suitable not only for researchers currently employing detection techniques in their research activity, but also for those approaching the subject for the fi

Roda, Aldo; Hastings, J Woodland

2010-01-01

140

Time Variant Change Analysis in Satellite Images  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes the time variant changes in satellite images using Self Organizing Feature Map (SOFM technique associated with Artificial Neural Network. In this paper, we take a satellite image and find the time variant changes using above technique with the help of MATLAB. This paper reviews remotely sensed data analysis with neural networks. First, we present an overview of the main concepts underlying Artificial Neural Networks (ANNs, including the main architectures and learning algorithms. Then, the main tasks that involve ANNs in remote sensing are described. We first make a brief introduction to models of networks, for then describing in general terms Artificial Neural Networks (ANNs. As an application, we explain the back propagation algorithm, since it is widely used and many other algorithms are derived from it. There are two techniques that are used for classification in pattern recognition such as Supervised Classification and Unsupervised Classification. In supervised learning technique the network knows about the target and it has to change accordingly to get the desired output corresponding to the presented input sample data. Most of the previous work has already been done on supervised classification. In this study we are going to present the classification of satellite images using unsupervised classification method of ANN.

Rachita Sharma

2013-05-01

141

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

Science.gov (United States)

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. PMID:24694875

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

2014-04-21

142

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

Science.gov (United States)

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.

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

2014-04-01

143

Real-Time Imaging of Quantum Entanglement  

International Nuclear Information System (INIS)

Full text: Photonic entanglement of spatial modes is routinely studied in many experiments and offers interesting features for quantum optical and quantum information experiments. To investigate the properties of these complex modes, it is crucial to gain information about the transversal structure with high precision and in an efficient way. We show that modern technology, namely triggered intensified charge coupled device (ICCD) cameras are fast and sensitive enough to image in real-time the effect of the measurement of one photon on the spatial mode of its entangled partner photon. We determine from imaged intensity pattern the number of photons within a certain region, evaluate its error margin and thereby quantitatively verify the non-classicality of the measurements. In addition, the use of the ICCD camera allows us to demonstrate visually the enhanced remote angular sensing and the high flexibility of our setup in creating any desired spatial-mode entanglement. (author)

144

Imaging of Disease Dynamics during Meningococcal Sepsis  

OpenAIRE

Neisseria meningitidis is a human pathogen that causes septicemia and meningitis with high mortality. The disease progression is rapid and much remains unknown about the disease process. The understanding of disease development is crucial for development of novel therapeutic strategies and vaccines against meningococcal disease. The use of bioluminescent imaging combined with a mouse disease model allowed us to investigate the progression of meningococcal sepsis over time. Injection of bacter...

Sjo?linder, Hong; Jonsson, Ann-beth

2007-01-01

145

Rapid obtention of stable, bioluminescent tumor cell lines using a tCD2-luciferase chimeric construct  

OpenAIRE

Abstract Background Bioluminescent tumor cell lines are experimental tools of major importance for cancer investigation, especially imaging of tumors in xenografted animals. Stable expression of exogenous luciferase in tumor cells combined to systemic injection of luciferin provides an excellent signal/background ratio for external optical imaging. Therefore, there is a need to rationalize and speed up the production of luciferase-positive tumor cell lines representative of multiple tumor phe...

Gourzones Claire; Wei Ming; Barjon Clément; Gressette Mélanie; Jimenez Anne-Sophie; Busson Pierre

2011-01-01

146

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.

147

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 algori 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

148

Three-dimensional light-tissue interaction models for bioluminescence tomography  

Science.gov (United States)

Many diagnostic and therapeutic approaches in medical physics today take advantage of the unique properties of light and its interaction with tissues. Because light scatters in tissue, our ability to develop these techniques depends critically on our knowledge of the distribution of light in tissue. Solutions to the diffusion equation can provide such information, but often lack the flexibility required for more general problems that involve, for instance, inhomogeneous optical properties, light polarization, arbitrary three-dimensional geometries, or arbitrary scattering. Monte Carlo techniques, which statistically sample the light distribution in tissue, offer a better alternative to analytical models. First, we discuss our implementation of a validated three-dimensional polarization-sensitive Monte Carlo algorithm and demonstrate its generality with respect to the geometry and scattering models it can treat. Second, we apply our model to bioluminescence tomography. After appropriate genetic modifications to cell lines, bioluminescence can be used as an indicator of cell activity, and is often used to study tumour growth and treatment in animal models. However, the amount of light escaping the animal is strongly dependent on the position and size of the tumour. Using forward models and structural data from magnetic resonance imaging, we show how the models can help to determine the location and size of tumour made of bioluminescent cancer cells in the brain of a mouse.

Côté, D.; Allard, M.; Henkelman, R. M.; Vitkin, I. A.

2005-09-01

149

Time Reversal Imaging of the Tsunami Source  

Science.gov (United States)

In this paper, we apply time reversal imaging (TRI) to the problem of reconstructing the initial sea surface displacement that generates a tsunami. We discuss theoretical considerations in the application of TRI to the tsunami problem, including time reversibility and reciprocity of the shallow-water equations. Several numerical experiments are conducted to establish the efficacy of TRI in the tsunami context. TRI is applied to observations of the tsunami generated by the Tohoku earthquake on March 11, 2011, for which an unprecedented number of high-quality observations are available. Finally, we compare the findings of the TRI results with other, more conventional methods of source inversion. Results indicate that TRI is effective for imaging a tsunami source when a sufficient number of observations are available. Because it involves fewer assumptions about the nature of the tsunami source, in particular those regarding source location and fault geometry, we believe that TRI has the potential to improve our understanding of tsunami generation—for example, through detection of non-seismic components of the tsunami source.

Hossen, M. Jakir; Cummins, Phil R.; Roberts, Stephen G.; Allgeyer, Sebastien

2015-02-01

150

Time Reversal Imaging of the Tsunami Source  

Science.gov (United States)

In this paper, we apply time reversal imaging (TRI) to the problem of reconstructing the initial sea surface displacement that generates a tsunami. We discuss theoretical considerations in the application of TRI to the tsunami problem, including time reversibility and reciprocity of the shallow-water equations. Several numerical experiments are conducted to establish the efficacy of TRI in the tsunami context. TRI is applied to observations of the tsunami generated by the Tohoku earthquake on March 11, 2011, for which an unprecedented number of high-quality observations are available. Finally, we compare the findings of the TRI results with other, more conventional methods of source inversion. Results indicate that TRI is effective for imaging a tsunami source when a sufficient number of observations are available. Because it involves fewer assumptions about the nature of the tsunami source, in particular those regarding source location and fault geometry, we believe that TRI has the potential to improve our understanding of tsunami generation—for example, through detection of non-seismic components of the tsunami source.

Hossen, M. Jakir; Cummins, Phil R.; Roberts, Stephen G.; Allgeyer, Sebastien

2015-03-01

151

A Short Image Series Based Scheme for Time Series Digital Image Correlation  

OpenAIRE

A new scheme for digital image correlation, i.e., short time series DIC (STS-DIC) is proposed. Instead of processing the original deformed speckle images individually, STS-DIC combines several adjacent deformed speckle images from a short time series and then processes the averaged image, for which deformation continuity over time is introduced. The deformation of several adjacent images is assumed to be linear in time and a new spatial-temporal displacement representation m...

Wang, Xian; Ma, Shaopeng

2014-01-01

152

Shedding light on bioluminescence regulation in Vibrio fischeri  

OpenAIRE

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...

Miyashiro, Tim; Ruby, Edward G.

2012-01-01

153

Deep-sea bioluminescence blooms after dense water formation at the ocean surface.  

Science.gov (United States)

The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as "open-sea convection". It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts. PMID:23874425

Tamburini, Christian; Canals, Miquel; Durrieu de Madron, Xavier; Houpert, Loïc; Lefèvre, Dominique; Martini, Séverine; D'Ortenzio, Fabrizio; Robert, Anne; Testor, Pierre; Aguilar, Juan Antonio; Samarai, Imen Al; Albert, Arnaud; André, Michel; Anghinolfi, Marco; Anton, Gisela; Anvar, Shebli; Ardid, Miguel; Jesus, Ana Carolina Assis; Astraatmadja, Tri L; Aubert, Jean-Jacques; Baret, Bruny; Basa, Stéphane; Bertin, Vincent; Biagi, Simone; Bigi, Armando; Bigongiari, Ciro; Bogazzi, Claudio; Bou-Cabo, Manuel; Bouhou, Boutayeb; Bouwhuis, Mieke C; Brunner, Jurgen; Busto, José; Camarena, Francisco; Capone, Antonio; Cârloganu, Christina; Carminati, Giada; Carr, John; Cecchini, Stefano; Charif, Ziad; Charvis, Philippe; Chiarusi, Tommaso; Circella, Marco; Coniglione, Rosa; Costantini, Heide; Coyle, Paschal; Curtil, Christian; Decowski, Patrick; Dekeyser, Ivan; Deschamps, Anne; Donzaud, Corinne; Dornic, Damien; Dorosti, Hasankiadeh Q; Drouhin, Doriane; Eberl, Thomas; Emanuele, Umberto; Ernenwein, Jean-Pierre; Escoffier, Stéphanie; Fermani, Paolo; Ferri, Marcelino; Flaminio, Vincenzo; Folger, Florian; Fritsch, Ulf; Fuda, Jean-Luc; Galatà, Salvatore; Gay, Pascal; Giacomelli, Giorgio; Giordano, Valentina; Gómez-González, Juan-Pablo; Graf, Kay; Guillard, Goulven; Halladjian, Garadeb; Hallewell, Gregory; van Haren, Hans; Hartman, Joris; Heijboer, Aart J; Hello, Yann; Hernández-Rey, Juan Jose; Herold, Bjoern; Hößl, Jurgen; Hsu, Ching-Cheng; de Jong, Marteen; Kadler, Matthias; Kalekin, Oleg; Kappes, Alexander; Katz, Uli; Kavatsyuk, Oksana; Kooijman, Paul; Kopper, Claudio; Kouchner, Antoine; Kreykenbohm, Ingo; Kulikovskiy, Vladimir; Lahmann, Robert; Lamare, Patrick; Larosa, Giuseppina; Lattuada, Dario; Lim, Gordon; Presti, Domenico Lo; Loehner, Herbert; Loucatos, Sotiris; Mangano, Salvatore; Marcelin, Michel; Margiotta, Annarita; Martinez-Mora, Juan Antonio; Meli, Athina; Montaruli, Teresa; Moscoso, Luciano; Motz, Holger; Neff, Max; Nezri, Emma Nuel; Palioselitis, Dimitris; P?v?la?, Gabriela E; Payet, Kevin; Payre, Patrice; Petrovic, Jelena; Piattelli, Paolo; Picot-Clemente, Nicolas; Popa, Vlad; Pradier, Thierry; Presani, Eleonora; Racca, Chantal; Reed, Corey; Riccobene, Giorgio; Richardt, Carsten; Richter, Roland; Rivière, Colas; Roensch, Kathrin; Rostovtsev, Andrei; Ruiz-Rivas, Joaquin; Rujoiu, Marius; Russo, Valerio G; Salesa, Francisco; Sánchez-Losa, Augustin; Sapienza, Piera; Schöck, Friederike; Schuller, Jean-Pierre; Schussler, Fabian; Shanidze, Rezo; Simeone, Francesco; Spies, Andreas; Spurio, Maurizio; Steijger, Jos J M; Stolarczyk, Thierry; Taiuti, Mauro G F; Toscano, Simona; Vallage, Bertrand; Van Elewyck, Véronique; Vannoni, Giulia; Vecchi, Manuela; Vernin, Pascal; Wijnker, Guus; Wilms, Jorn; de Wolf, Els; Yepes, Harold; Zaborov, Dmitry; De Dios Zornoza, Juan; Zúñiga, Juan

2013-01-01

154

Deep-Sea Bioluminescence Blooms after Dense Water Formation at the Ocean Surface  

Science.gov (United States)

The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as “open-sea convection”. It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts. PMID:23874425

Tamburini, Christian; Canals, Miquel; Durrieu de Madron, Xavier; Houpert, Loïc; Lefèvre, Dominique; Martini, Séverine; D'Ortenzio, Fabrizio; Robert, Anne; Testor, Pierre; Aguilar, Juan Antonio; Samarai, Imen Al; Albert, Arnaud; André, Michel; Anghinolfi, Marco; Anton, Gisela; Anvar, Shebli; Ardid, Miguel; Jesus, Ana Carolina Assis; Astraatmadja, Tri L.; Aubert, Jean-Jacques; Baret, Bruny; Basa, Stéphane; Bertin, Vincent; Biagi, Simone; Bigi, Armando; Bigongiari, Ciro; Bogazzi, Claudio; Bou-Cabo, Manuel; Bouhou, Boutayeb; Bouwhuis, Mieke C.; Brunner, Jurgen; Busto, José; Camarena, Francisco; Capone, Antonio; Cârloganu, Christina; Carminati, Giada; Carr, John; Cecchini, Stefano; Charif, Ziad; Charvis, Philippe; Chiarusi, Tommaso; Circella, Marco; Coniglione, Rosa; Costantini, Heide; Coyle, Paschal; Curtil, Christian; Decowski, Patrick; Dekeyser, Ivan; Deschamps, Anne; Donzaud, Corinne; Dornic, Damien; Dorosti, Hasankiadeh Q.; Drouhin, Doriane; Eberl, Thomas; Emanuele, Umberto; Ernenwein, Jean-Pierre; Escoffier, Stéphanie; Fermani, Paolo; Ferri, Marcelino; Flaminio, Vincenzo; Folger, Florian; Fritsch, Ulf; Fuda, Jean-Luc; Galatà, Salvatore; Gay, Pascal; Giacomelli, Giorgio; Giordano, Valentina; Gómez-González, Juan-Pablo; Graf, Kay; Guillard, Goulven; Halladjian, Garadeb; Hallewell, Gregory; van Haren, Hans; Hartman, Joris; Heijboer, Aart J.; Hello, Yann; Hernández-Rey, Juan Jose; Herold, Bjoern; Hößl, Jurgen; Hsu, Ching-Cheng; de Jong, Marteen; Kadler, Matthias; Kalekin, Oleg; Kappes, Alexander; Katz, Uli; Kavatsyuk, Oksana; Kooijman, Paul; Kopper, Claudio; Kouchner, Antoine; Kreykenbohm, Ingo; Kulikovskiy, Vladimir; Lahmann, Robert; Lamare, Patrick; Larosa, Giuseppina; Lattuada, Dario; Lim, Gordon; Presti, Domenico Lo; Loehner, Herbert; Loucatos, Sotiris; Mangano, Salvatore; Marcelin, Michel; Margiotta, Annarita; Martinez-Mora, Juan Antonio; Meli, Athina; Montaruli, Teresa; Motz, Holger; Neff, Max; Nezri, Emma nuel; Palioselitis, Dimitris; P?v?la?, Gabriela E.; Payet, Kevin; Payre, Patrice; Petrovic, Jelena; Piattelli, Paolo; Picot-Clemente, Nicolas; Popa, Vlad; Pradier, Thierry; Presani, Eleonora; Racca, Chantal; Reed, Corey; Riccobene, Giorgio; Richardt, Carsten; Richter, Roland; Rivière, Colas; Roensch, Kathrin; Rostovtsev, Andrei; Ruiz-Rivas, Joaquin; Rujoiu, Marius; Russo, Valerio G.; Salesa, Francisco; Sánchez-Losa, Augustin; Sapienza, Piera; Schöck, Friederike; Schuller, Jean-Pierre; Schussler, Fabian; Shanidze, Rezo; Simeone, Francesco; Spies, Andreas; Spurio, Maurizio; Steijger, Jos J. M.; Stolarczyk, Thierry; Taiuti, Mauro G. F.; Toscano, Simona; Vallage, Bertrand; Van Elewyck, Véronique; Vannoni, Giulia; Vecchi, Manuela; Vernin, Pascal; Wijnker, Guus; Wilms, Jorn; de Wolf, Els; Yepes, Harold; Zaborov, Dmitry; De Dios Zornoza, Juan; Zúñiga, Juan

2013-01-01

155

REAL-TIME MULTISPECTRAL IMAGING APPLICATION FOR POULTRY SAFETY INSPECTION  

Science.gov (United States)

Industrial-scale multispectral imaging system with real-time image processing software for on-line detection of poultry fecal and ingesta contaminants was developed. The software using Unified Modeling Language (UML) design approach was effective to develop real-time image processing software for o...

156

Dual monitoring using {sup 124}I-FIAU and bioluminescence for HSV1-tk suicide gene therapy  

Energy Technology Data Exchange (ETDEWEB)

Herpes simplex virus type I thymidine kinase (HSV-tk) is the most common reporter gene and is used in cancer gene therapy with a prodrug nucleoside analog, ganciclovir (GCV). The aim of this study is to evaluate therapeutic efficacy of suicide gene therapy with 2'-fluoro-2'-deoxy-1-D-arabinofuranosyl-5-[{sup 124}I] iodouracil ({sup 124}I - FIAU) and bioluminescence in retrovirally HSV -tk and firefly luciferase transduced hepatoma model. The HSV -tk and firefly luciferase (Luc) was retrovirally transduced and expressed in MCA rat Morris hepatoma cells. Nude mice with subcutaneous tumors, MCA and MCA-TK-Luc, were subjected to GCV treatment (50mg/Kg/d intraperitoneally) for 5 day. PET imaging and biodistribution with ({sup 124}I-FIAU) were performed at before and after initiation of therapy with GCV. Bioluminescent signal was also measured during GCV treatment. Before GCV treatment, no significant difference in tumor volume was found in tumors between MCA and MCA-TK-Luc. After GCV treatment, tumor volume of MCA-TK-Luc markedly reduced compared to that of MCA. In biodistribution study, {sup 124}I-FIAU uptake after GCV therapy significantly decreased compared with pretreatment levels (34.8 13.67 %ID/g vs 7.6 2.59 %ID/g) and bioluminescent signal was also significantly decreased compared with pretreatment levels. In small animal PET imaging, {sup 124}I-FIAU selectively localized in HSV -tk expressing tumor and the therapeutic efficacy of GCV treatment was evaluated by {sup 124}I-FIAU PET imaging. {sup 124}I-FIAU PET and bioluminescence imaging in HSV-tk suicide gene therapy were effective to evaluate the therapeutic response. {sup 124}I-FIAU may serve as an efficient and selective agent for monitoring of transduced HSV1-tk gene expression in vivo in clinical trials.

Lee, T. S.; Kim, J. H.; Kwon, H. C. [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)] (and others)

2007-07-01

157

Tumor cell-specific bioluminescence platform to identify stroma-induced changes to anti-cancer drug activity  

OpenAIRE

Conventional anti-cancer drug screening is typically performed in the absence of accessory cells of the tumor microenvironment, which can profoundly alter anti-tumor drug activity. To address this major limitation, we developed the tumor cell-specific in vitro bioluminescence imaging (CS-BLI) assay. Tumor cells (e.g. myeloma, leukemia and solid tumors) stably expressing luciferase are co-cultured with non-malignant accessory cells (e.g. stromal cells) for selective quantification of tumor cel...

Mcmillin, Douglas W.; Delmore, Jake; Weisberg, Ellen; Negri, Joseph M.; Geer, D. Corey; Klippel, Steffen; Mitsiades, Nicholas; Schlossman, Robert L.; Munshi, Nikhil C.; Kung, Andrew L.; Griffin, James D.; Richardson, Paul G.; Anderson, Kenneth C.; Mitsiades, Constantine S.

2010-01-01

158

A Novel Mouse Model of Soft-Tissue Infection Using Bioluminescence Imaging Allows Noninvasive, Real-Time Monitoring of Bacterial Growth  

OpenAIRE

Musculoskeletal infections, including surgical-site and implant-associated infections, often cause progressive inflammation and destroy areas of the soft tissue. Treating infections, especially those caused by multi-antibiotic resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge. Although there are a few animal models that enable the quantitative evaluation of infection in soft tissues, these models are not always reproducible or sustainable. Here,...

Yoshioka, Kenji; Ishii, Ken; Kuramoto, Tetsuya; Nagai, Shigenori; Funao, Haruki; Ishihama, Hiroko; Shiono, Yuta; Sasaki, Aya; Aizawa, Mamoru; Okada, Yasunori; Koyasu, Shigeo; Toyama, Yoshiaki; Matsumoto, Morio

2014-01-01

159

Time-delay compensation for stabilization imaging system  

Science.gov (United States)

The spatial resolution of imaging systems for airborne and space-borne remote sensing are often limited by image degradation resulting from mechanical vibrations of platforms during image exposure. A straightforward way to overcome this problem is to actively stabilize the optical axis or drive the focal plane synchronous to the motion image during exposure. Thus stabilization imaging system usually consists of digital image motion estimation and micromechanical compensation. The performance of such kind of visual servo system is closely related to precision of motion estimation and time delay. Large time delay results in larger phase delay between motion estimation and micromechanical compensation, and leads to larger uncompensated residual motion and limited bandwidth. The paper analyzes the time delay caused by image acquisition period and introduces a time delay compensation method based on SVM (Support Vector Machine) motion prediction. The main idea to cancel the time delay is to predict the current image motion from delayed measurements. A support vector machine based method is designed to predict the image motion. A prototype of stabilization imaging system has been implemented in the lab. To analyze the influences of time delay on system performance and to verify the proposed time delay cancelation method, comparative experiments over various frequencies of vibration are taken. The experimental results show that, the accuracy of motion compensation and the bandwidth of the system can be significantly improved with time delay cancelation.

Chen, Yueting; Xu, Zhihai; Li, Qi; Feng, Huajun

2014-05-01

160

Real time neutron radiography using a Lixi neutron imaging device  

International Nuclear Information System (INIS)

A real time neutron radiography system has been developed at the University of Michigan Phoenix Memorial Laboratory (PML) and has recently been used to test the imaging capabilities of a neutron imaging device developed by Lixi, Inc. of Downers Grove, Ill. This device uses an input phosphor that is high in gadolinium to generate a light image which is then sent through an intensifier stage to provide images that can be viewed by eye, video camera, or standard 35 mm camera. It was determined that this device provides images of much higher resolution and sensitivity than those obtained with the imaging system currently being used at PML. Using computerized image enhancement techniques, the images obtained with the Lixi neutron imaging device can then be further enhanced or processed to obtain quantitative information on the object being imaged. (orig.)

161

A look at some systemic properties of self-bioluminescent emission  

Science.gov (United States)

Self-bioluminescent emission (SBE) is a type of biological chemiluminescence where photons are emitted as part of chemical reactions occurring during metabolic processes. This emission is also known as biophoton emission, ultraweak photon emission and ultraweak bioluminescence. This paper outlines research over the past century on some systemic properties of SBE as measured with biological detectors, photomultiplier detectors and ultra-sensitive imaging arrays. There is an apparent consensus in the literature that emission in the deep blue and ultraviolet (150-450nm) is related to DNA / RNA processes while emission in the red and near infrared (600-1000nm) is related to mitochondria and oxidative metabolisms involving reactive oxygen species, singlet oxygen and free radicals in plant, animal and human cells along with chlorophyll fluorescent decay in plants. Additionally, there are trends showing that healthy, unstressed and uninjured samples have less emission than samples that are unhealthy, stressed or injured. Mechanisms producing this emission can be narrowed down by isolating the wavelength region of interest and waiting for short-term fluorescence to decay leaving the ultraweak long-term metabolic emission. Examples of imaging this emission in healthy versus unhealthy, stressed versus unstressed, and injured versus uninjured plant parts are shown. Further discussion poses questions still to be answered related to properties such as coherence, photon statistics, and methodological means of isolating mechanisms.

Creath, Katherine

2008-08-01

162

Adenosine triphosphate bioluminescence as a method to determine microbial levels in scald and chill tanks at a poultry abattoir.  

Science.gov (United States)

According to Hazard Analysis of Critical Control Points (HACCP) programs developed for the poultry industry, poultry processing waters should be actively monitored to minimize cross-contamination between chicken carcasses. In order to monitor HACCP programs, a test is required that provides results on a real time basis. A modified adenosine triphosphate (ATP) bioluminescence test has been developed that can assess microbial levels in poultry processing waters within 15 min. A study was conducted to determine the effectiveness of this test for examining scald, prechill, and chill tank waters. The results showed that the modified ATP bioluminescence method gave results comparable to plate counts. The microbial levels were dependent on the tank and the time of sampling. The highest microbial levels were detected in the scald tank. In all three tanks, the microbial levels increased over time during the day. PMID:7862606

Bautista, D A; Vaillancourt, J P; Clarke, R A; Renwick, S; Griffiths, M W

1994-11-01

163

Multimodal MR imaging of acute and subacute experimental traumatic brain injury: Time course and correlation with cerebral energy metabolites  

Science.gov (United States)

Background Traumatic brain injury (TBI) is one of the leading causes of death and permanent disability world-wide. The predominant cause of death after TBI is brain edema which can be quantified by non-invasive diffusion-weighted magnetic resonance imaging (DWI). Purpose To provide a better understanding of the early onset, time course, spatial development, and type of brain edema after TBI and to correlate MRI data and the cerebral energy state reflected by the metabolite adenosine triphosphate (ATP). Material and Methods The spontaneous development of lateral fluid percussion-induced TBI was investigated in the acute (6?h), subacute (48?h), and chronic (7 days) phase in rats by MRI of quantitative T2 and apparent diffusion coefficient (ADC) mapping as well as perfusion was combined with ATP-specific bioluminescence imaging and histology. Results An induced TBI led to moderate to mild brain damages, reflected by transient, pronounced development of vasogenic edema and perfusion reduction. Heterogeneous ADC patterns indicated a parallel, but mixed expression of vasogenic and cytotoxic edema. Cortical ATP levels were reduced in the acute and subacute phase by 13% and 27%, respectively, but were completely normalized at 7 days after injury. Conclusion The partial ATP reduction was interpreted to be partially caused by a loss of neurons in parallel with transient dilution of the regional ATP concentration by pronounced vasogenic edema. The normalization of energy metabolism after 7 days was likely due to infiltrating glia and not to recovery. The MRI combined with metabolite measurement further improves the understanding and evaluation of brain damages after TBI. PMID:25610615

Maegele, Marc; Hoeffgen, Alexander; Uhlenkueken, Ulla; Mautes, Angelika; Schaefer, Nadine; Lippert-Gruener, Marcela; Schaefer, Ute; Hoehn, Mathias

2015-01-01

164

Real-time imaging of ATP release induced by mechanical stretch in human airway smooth muscle cells.  

Science.gov (United States)

Airway smooth muscle (ASM) cells within the airway walls are continually exposed to mechanical stimuli, and exhibit various functions in response to these mechanical stresses. ATP acts as an extracellular mediator in the airway. Moreover, extracellular ATP is considered to play an important role in the pathophysiology of asthma and chronic obstructive pulmonary disease. However, it is not known whether ASM cells are cellular sources of ATP secretion in the airway. We therefore investigated whether mechanical stretch induces ATP release from ASM cells. Mechanical stretch was applied to primary human ASM cells cultured on a silicone chamber coated with type I collagen using a stretching apparatus. Concentrations of ATP in cell culture supernatants measured by luciferin-luciferase bioluminescence were significantly elevated by cyclic stretch (12 and 20% strain). We further visualized the stretch-induced ATP release from the cells in real time using a luminescence imaging system, while acquiring differential interference contrast cell images with infrared optics. Immediately after a single uniaxial stretch for 1 second, strong ATP signals were produced by a certain population of cells and spread to surrounding spaces. The cyclic stretch-induced ATP release was significantly reduced by inhibitors of Ca(2+)-dependent vesicular exocytosis, 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester, monensin, N-ethylmaleimide, and bafilomycin. In contrast, the stretch-induced ATP release was not inhibited by a hemichannel blocker, carbenoxolone, or blockade of transient receptor potential vanilloid 4 by short interfering RNA transfection or ruthenium red. These findings reveal a novel property of ASM cells: mechanically induced ATP release may be a cellular source of ATP in the airway. PMID:24885163

Takahara, Norihiro; Ito, Satoru; Furuya, Kishio; Naruse, Keiji; Aso, Hiromichi; Kondo, Masashi; Sokabe, Masahiro; Hasegawa, Yoshinori

2014-12-01

165

Real-time digital x-ray subtraction imaging  

International Nuclear Information System (INIS)

A method of producing visible difference images derived from an x-ray image of an anatomical subject is described. X-rays are directed through the subject, and the image is converted into television fields comprising trains of analog video signals. The analog signals are converted into digital signals, which are then integrated over a predetermined time corresponding to several television fields. Difference video signals are produced by performing a subtraction between the ongoing video signals and the corresponding integrated signals, and are converted into visible television difference images representing changes in the x-ray image

166

Digital subtraction angiography (DSA) with real-time functional imaging  

International Nuclear Information System (INIS)

The real-time functional imaging method has been tested in the Tuttlingen hospital using a newly installed pilot system. The coloured functional images provide a good and easily readable report of the contrast medium flow. The images are based on reduced data, showing the temporal changes of contrast medium flow at the individual image points. Single images can be stored via data compression. Temporal functional changes can be electronically stored and documented without having recourse to a motion picture film or a large mass storage device. (orig.)

167

THz time-domain spectroscopy imaging for mail inspection  

Science.gov (United States)

Acquiring messages from the mail but not destroying the envelope is a big challenge in the war of intelligence. If one can read the message of the mail when the envelope is closed, he will benefit from the message asymmetry and be on a good wicket in the competition. In this paper, we presented a transmitted imaging system using THz time-domain spectroscopy technology. We applied the system to image the mail inside an envelope by step-scanning imaging technology. The experimental results show that the THz spectroscopy can image the mail in an envelope. The words in the paper can be identified easily from the background. We also present the THz image of a metal blade in the envelope, in which we can see the metal blade clearly. The results show that it is feasible of THz Time-Domain Spectroscopy Imaging for mail inspection applications.

Zhang, Liquan; Wang, Zhongdong; Ma, Yanmei; Hao, Erjuan

2011-08-01

168

Real-time digital x-ray subtraction imaging  

International Nuclear Information System (INIS)

The invention provides a method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through the anatomical subject for producing an image, converting the image into television fields comprising trains of on-going video signals, digitally storing and integrating the on-going video signals over a time interval corresponding to several successive television fields and thereby producing stored and integrated video signals, recovering the video signals from storage and producing integrated video signals, producing video difference signals by performing a subtraction between the integrated video signals and the on-going video signals outside the time interval, and converting the difference signals into visible television difference images representing on-going changes in the X-ray image

169

Photographic documentation in real time radiographic imaging procedures and other inspection procedures using video imaging techniques  

International Nuclear Information System (INIS)

With an automatic daylight video imaging system, based on the use of wet processing type of film, it is possible to produce permanent documents of real time video images with almost the same convenience as video tape recording while maintaining all the advantages of display flexibility and image quality offered by photographic documents

170

In vivo quantitative bioluminescence tomography using heterogeneous and homogeneous mouse models.  

Science.gov (United States)

Bioluminescence tomography (BLT) is a new optical molecular imaging modality, which can monitor both physiological and pathological processes by using bioluminescent light-emitting probes in small living animal. Especially, this technology possesses great potential in drug development, early detection, and therapy monitoring in preclinical settings. In the present study, we developed a dual modality BLT prototype system with Micro-computed tomography (MicroCT) registration approach, and improved the quantitative reconstruction algorithm based on adaptive hp finite element method (hp-FEM). Detailed comparisons of source reconstruction between the heterogeneous and homogeneous mouse models were performed. The models include mice with implanted luminescence source and tumor-bearing mice with firefly luciferase report gene. Our data suggest that the reconstruction based on heterogeneous mouse model is more accurate in localization and quantification than the homogeneous mouse model with appropriate optical parameters and that BLT allows super-early tumor detection in vivo based on tomographic reconstruction of heterogeneous mouse model signal. PMID:20588440

Liu, Junting; Wang, Yabin; Qu, Xiaochao; Li, Xiangsi; Ma, Xiaopeng; Han, Runqiang; Hu, Zhenhua; Chen, Xueli; Sun, Dongdong; Zhang, Rongqing; Chen, Duofang; Chen, Dan; Chen, Xiaoyuan; Liang, Jimin; Cao, Feng; Tian, Jie

2010-06-01

171

Volumetric Real-Time Imaging Using a CMUT Ring Array  

OpenAIRE

A ring array provides a very suitable geometry for forward-looking volumetric intracardiac and intravascular ultrasound imaging. We fabricated an annular 64-element capacitive micromachined ultrasonic transducer (CMUT) array featuring a 10-MHz operating frequency and a 1.27-mm outer radius. A custom software suite was developed to run on a PC-based imaging system for real-time imaging using this device.

Choe, Jung Woo; Oralkan, O?mer; Nikoozadeh, Amin; Gencel, Mustafa; Stephens, Douglas N.; O’donnell, Matthew; Sahn, David J.; Khuri-yakub, Butrus T.

2012-01-01

172

Real-time lucky imaging in FastCam project  

Science.gov (United States)

Lucky imaging techniques implemented by the FastCam group (see http://www.iac.es/proyecto/fastcam/) at the Instituto de Astrofisica de Canarias have demonstrated its ability to obtain spectacular diffraction limited images in telescopes ranging from 1 to 4.2 m in visible wavelengths (mainly in the I band), at the expense of using only a small percentage of the available images. This work presents the development of a real-time processor, FPGA-based, capable of performing all the required processing involved in the lucky imaging technique: Bias and flat-field correction, quality evaluation of images, quality threshold for image selection, image recentering and accumulation, and finally sending through Gigabit Ethernet both raw and processed images to a PC computer. Furthermore, a real time display is generated directly from FPGA showing both types of images, plus a histogram of the computed quality values and the threshold used. All processes can co-exist physically located in separated places inside the FPGA, using its natural parallel approach, and can easily handle the 512x512 pixels at 30 fps found at the sensor camera output (an Andor Ixon+ DU-897ECSO EMCCD). Flexibility and parallel processing features of the reconfigurable logic have been used to implement a novel imaging strategy for segmented-mirror telescopes, allowing separate evaluation of every segment and posterior accumulation to achieve the resolution limit of a single segment with the integration capability of the full primary mirror.

Rodríguez Ramos, L. F.; Piqueras Meseguer, J. J.; Martin Hernando, Y.; Oscoz, A.; Rebolo, R.

2008-07-01

173

Adaptive Real Time Imaging Synthesis Telescopes  

CERN Document Server

The digital revolution is transforming astronomy from a data-starved to a data-submerged science. Instruments such as the Atacama Large Millimeter Array (ALMA), the Large Synoptic Survey Telescope (LSST), and the Square Kilometer Array (SKA) will measure their accumulated data in petabytes. The capacity to produce enormous volumes of data must be matched with the computing power to process that data and produce meaningful results. In addition to handling huge data rates, we need adaptive calibration and beamforming to handle atmospheric fluctuations and radio frequency interference, and to provide a user environment which makes the full power of large telescope arrays accessible to both expert and non-expert users. Delayed calibration and analysis limit the science which can be done. To make the best use of both telescope and human resources we must reduce the burden of data reduction. Our instrumentation comprises of a flexible correlator, beam former and imager with digital signal processing closely coupled...

Wright, Melvyn

2012-01-01

174

Real time magneto-optical imaging of vortices in superconductors  

OpenAIRE

We demonstrate here real-time imaging of individual vortices in a NbSe2 single crystal using polarized light microscopy. A new high-sensitivity magneto-optical (MO) imaging system enables observation of the static vortex lattice as well as single vortex motion at low flux densities.

Goa, Paal Erik; Hauglin, Harald; Baziljevich, Michael; Il Yashenko, Eugene; Gammel, Peter L.; Johansen, Tom H.

2001-01-01

175

Terrain adaptive footfall placement using real-time range images  

Science.gov (United States)

This paper discusses the design of a four-legged robot which has a laser mounted on each leg which provides a real-time high-definition range image of the ground surroundings about each leg. A means of terrain classification using fractals and methods for the automatic extraction of information from the range images having implications for footfall placement are provided.

Dodds, David R.

1991-03-01

176

Evaluation of cardiopulmonary circulation time with functional images  

International Nuclear Information System (INIS)

Functional images of circulation time, peak time image and half time image, were generated using a scintillation camera with a minicomputer system. Peak time image represents the progression of a bolus through heart, lungs and great vessels. Half time image is considered to reflect the regional clearance of the tracer. Normal values of peak time and half time were determined from subjects without evidence of cardiopulmonary disease. Normal values (n = 20) of peak time were: superior vena cava (SVC), always designated to 1 sec; right ventricle (RV), 2.0 +- 0.3 (SD) sec; lungs 4.5 +- 0.5 sec; left ventricle (LV), 7.6 +- 0.7 sec and that of half time were: RV, 2.0 +- 0.6 (SD) sec; right lung, 3.2 +- 0.5 sec; left lung, 3.3 +- 0.6 sec; LV, 3.8 +- 0.9 sec. In case of ischemic heart disease, these parameters were significantly delayed and supposed to be useful for the evaluations of cardiopulmonary hemodynamics. (author)

177

Telemetry Timing Analysis for Image Reconstruction of Kompsat Spacecraft  

Science.gov (United States)

The KOMPSAT (KOrea Multi-Purpose SATellite) has two optical imaging instruments called EOC (Electro-Optical Camera) and OSMI (Ocean Scanning Multispectral Imager). The image data of these instruments are transmitted to ground station and restored correctly after post-processing with the telemetry data transferred from KOMPSAT spacecraft. The major timing information of the KOMPSAT is OBT (On-Board Time) which is formatted by the on-board computer of the spacecraft, based on 1Hz sync. pulse coming from the GPS receiver involved. The OBT is transmitted to ground station with the house-keeping telemetry data of the spacecraft while it is distributed to the instruments via 1553B data bus for synchronization during imaging and formatting. The timing information contained in the spacecraft telemetry data would have direct relation to the image data of the instruments, which should be well explained to get a more accurate image. This paper addresses the timing analysis of the KOMPSAT spacecraft and instruments, including the gyro data timing analysis for the correct restoration of the EOC and OSMI image data at ground station.

Lee, Jin-Ho; Chang, Young-Keun

2000-06-01

178

Real time K-edge subtraction x-ray imaging  

International Nuclear Information System (INIS)

This paper describes an x-ray K-edge subtraction television system for noninvasive angiography utilizing synchrotron radiation. The phantom, including contrast material (iodine), is irradiated by monochromatized dual-energy x-ray flux, alternately, using a high speed monochromator. The monochromator consists of a silicon crystal plate vibrating at 15 Hz so that the phantom is irradiated by the x-ray flux of 150 eV above and below the K-edge photon energy of iodine, 15 times per second. As an x-ray detector, TV cameras optically coupled to an x-ray image intensifier are used and the video signal is processed to display the subtraction image of pairs of successive images in real time. This system was fully implemented and moving phantoms were examined. Both the time interval between the energy change and the exposure time of each image has been shortened to 2 ms

179

Rapid time-gated polarimetric Stokes imaging using photoelastic modulators.  

Science.gov (United States)

We report a rapid time-gated full Stokes imaging approach without mechanically moving parts, which is well-suited for biomedical applications, using two photoelastic modulators (PEMs). A charge-coupled device (CCD) with microsecond time-gating capability was used to acquire the images. To synchronize the CCD with the PEMs, thus gaining signal-to-noise ratio advantage, a field programmable gate array was employed. After calibration, an evolutionary algorithm was used to select four time points from which the full Stokes vector can be recovered. Using the images taken by the camera at these four times (in ~80 ms), the images of the full Stokes vectors of different incident polarization states were accurately derived. PMID:24104631

Alali, Sanaz; Yang, Tianyu; Vitkin, I Alex

2013-08-15

180

Validation of constitutively expressed bioluminescent Pseudomonas aeruginosa as a rapid microbiological quantification tool.  

Science.gov (United States)

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. PMID:25618377

Shah, N; Naseby, D C

2015-06-15

181

Time-dependent image potential at a metal surface  

International Nuclear Information System (INIS)

Transient effects in the image potential induced by a point charge suddenly created in front of a metal surface are studied. The time evolution of the image potential is calculated using linear response theory. Two different time scales are defined: (i) the time required for the creation of the image potential and (ii) the time it takes to converge to its stationary value. Their dependence on the distance of the charge to the surface is discussed. The effect of the electron gas damping is also analyzed. For a typical metallic density, the order of magnitude of the creation time is 0.1 fs, whereas for a charge created close to the surface the convergence time is around 1-2 fs

182

Real time neutron image processing system in NRF  

International Nuclear Information System (INIS)

The neutron radiography facility was installed at the neutron radiography beam tube of the HANARO research reactor. The NRF is used for the nondestructive test to inspect and evaluate the material defect and homogeneity by detecting the transmitted neutron image in the nuclear as well as non-nuclear industry. To analyze the dynamical neutron image effectively and efficiently, the real-time image processing system was developed in background subtraction, normalization, geometry correction and beam uniformity, contrast control, filtering. The image quality test and dimension measurements were performed for the neutron beam purity and sensitivity indication. The NRF beam condition represents the highest beam quality for neutron radiography.

183

Real-time absorption reduced surface fluorescence imaging  

Science.gov (United States)

We introduce a technique that limits absorption effects in fluorescence imaging and does not require extensive imaging processing, thus allowing for video rate imaging. The absorption minimization is achieved using spatial frequency domain imaging at a single high spatial frequency with standard three-phase demodulation. At a spatial frequency f=0.5 mm-1, we demonstrated in both in-vitro phantoms and ex-vivo tissue that the absorption can be significantly reduced. In the real-time implementation, we achieved a video rate of 19 frames/s. This technique has potential in cancer visualization and tumor margin detection.

Yang, Bin; Tunnell, James W.

2014-09-01

184

Sensitive in vivo imaging of T cells utilizing a membrane bound Gaussia princeps luciferase enzyme  

OpenAIRE

We developed a novel approach to bioluminescent T cell imaging (BLI) using a membrane-anchored form of the Gaussia luciferase (GLuc) enzyme, termed extGLuc, which we could stably express in both mouse and human primary T cells. In vitro, extGLuc+ cells emitted significantly higher bioluminescent signal when compared to cells expressing GLuc, Renilla luciferase (RLuc), and membrane-anchored RLuc (extRLuc). In vivo, mouse extGLuc+ T cells exhibited higher bioluminescent signal when compared to ...

Santos, Elmer B.; Yeh, Raymond; Lee, James; Nikhamin, Yan; Punzalan, Blesida; Punzalan, Bleserene; La Perle, Krista; Larson, Steven M.; Sadelain, Michel; Brentjens, Renier J.

2009-01-01

185

In Vivo Real-Time, Multicolor, Quantum Dot Lymphatic Imaging  

OpenAIRE

The lymphatic network is complex and difficult to visualize in real-time in vivo. Moreover, the direction of flow within lymphatic networks is often unpredictable especially in areas with well-developed “watershed” or overlapping lymphatics. Herein, we report a method of in vivo real-time multicolor lymphatic imaging using cadmium–selenium quantum dots (Qdots) with a fluorescence imaging system that enables the simultaneous visualization of up to five distinct lymphatic basins in real-t...

Kosaka, Nobuyuki; Ogawa, Mikako; Sato, Noriko; Choyke, Peter L.; Kobayashi, Hisataka

2009-01-01

186

Imaging source with Gaussian proper time distribution  

International Nuclear Information System (INIS)

Making use of the maximum entropy method, we study the most probable source function in heavy ion collisions. An anisotropic Gaussian source is deduced by simply assuming that the particles are emitted within a finite proper-time. The general relations between the most probable source function and the minimal assumptions are discussed, which are instructive in constructing a self-consistent source function from observed Hanbury-Brown/Twiss (HBT) correlations. (authors)

187

Real-Time Implementation of Medical Ultrasound Strain Imaging System  

International Nuclear Information System (INIS)

Strain imaging in a medical ultrasound imaging system can differentiate the cancer or tumor in a lesion that is stiffer than the surrounding tissue. In this paper, a strain imaging technique using quasistatic compression is implemented that estimates the displacement between pre- and postcompression ultrasound echoes and obtains strain by differentiating it in the spatial direction. Displacements are computed from the phase difference of complex baseband signals obtained using their autocorrelation, and errors associated with converting the phase difference into time or distance are compensated for by taking into the center frequency variation. Also, to reduce the effect of operator's hand motion, the displacements of all scanlines are normalized with the result that satisfactory strain image quality has been obtained. These techniques have been incorporated into implementing a medical ultrasound strain imaging system that operates in real time.

188

Sensitive in vivo imaging of T cells utilizing a membrane bound Gaussia princeps luciferase enzyme  

Science.gov (United States)

We developed a novel approach to bioluminescent T cell imaging (BLI) using a membrane-anchored form of the Gaussia luciferase (GLuc) enzyme, termed extGLuc, which we could stably express in both mouse and human primary T cells. In vitro, extGLuc+ cells emitted significantly higher bioluminescent signal when compared to cells expressing GLuc, Renilla luciferase (RLuc), and membrane-anchored RLuc (extRLuc). In vivo, mouse extGLuc+ T cells exhibited higher bioluminescent signal when compared to GLuc+ and RLuc+ T cells. Application of this imaging approach to human T cells genetically modified to express tumor-specific chimeric antigen receptors (CARs) enabled us to demonstrate in vivo CAR-mediated T cell accumulation in tumor, T cell persistence over time, and concomitant imaging of T cells and tumor cells modified to express firefly luciferase (FFLuc). This sensitive imaging technology has application to many in vivo cell based studies in a wide array of mouse models. PMID:19219023

Santos, Elmer B; Yeh, Raymond; Lee, James; Nikhamin, Yan; Punzalan, Blesida; Punzalan, Bleserene; La Perle, Krista; Larson, Steven M; Sadelain, Michel; Brentjens, Renier J

2009-01-01

189

[A technology of real-time image compression for convex grating imaging spectrometer].  

Science.gov (United States)

The huge amount of convex grating imaging spectrometer image data brings much pressure to data transmission and storage, so the image must be compressed in real time. Firstly, the image characteristics were analyzed according to the imaging principle, and the compression approach to removing spatial correlation and spectral correlation was achieved; Secondly, the compression algorithms were analyzed and the 3-D compression scheme of one-order linear compression in spectral dimension and JPEG2000 compression in spatial dimension was proposed. Finally, a real-time compression system based on FPGA and ADV212 was designed, in which FPGA was used for logic control and implementation of prediction algorithm, and ADV212 was used for JPEG2000 compression. The analysis result shows that the system has the ability of lossless and lossy compression, enabling real-time image compression. PMID:22715801

Liu, Yang-chuan; Bayanheshig; Cui, Ji-cheng; Tang, Yu-guo

2012-04-01

190

A Short Image Series Based Scheme for Time Series Digital Image Correlation  

CERN Document Server

A new scheme for digital image correlation, i.e., short time series DIC (STS-DIC) is proposed. Instead of processing the original deformed speckle images individually, STS-DIC combines several adjacent deformed speckle images from a short time series and then processes the averaged image, for which deformation continuity over time is introduced. The deformation of several adjacent images is assumed to be linear in time and a new spatial-temporal displacement representation method with eight unknowns is presented based on the subset-based representation method. Then, the model of STS-DIC is created and a solving scheme is developed based on the Newton-Raphson iteration. The proposed method is verified for numerical and experimental cases. The results show that the proposed STS-DIC greatly improves the accuracy of traditional DIC, both under simple and complicated deformation conditions, while retaining acceptable actual computational cost.

Wang, Xian

2014-01-01

191

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

Science.gov (United States)

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.

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

2014-11-01

192

Effect of exposure time and image resolution on fractal dimension  

International Nuclear Information System (INIS)

To evaluate the effect of exposure time and image resolution on fractal dimension calculations for determining the optimal range of these two variances. Thirty-one radiographs of the mandibular angle area of sixteen human dry mandibles were taken at different exposure times (0.01, 0.08, 0.16, 0.25, 0.40, 0.64, and 0.80 s). Each radiograph was digitized at 1200 dpi, 8 bit, 256 gray level using a film scanner. We selected an Region of Interest (ROI) that corresponded to the same region as in each radiograph, but the resolution of ROI was degraded to 1000, 800, 600, 500, 400, 300, 200, and 100 dpi. The fractal dimension was calculated by using the tile-counting method for each image, and the calculated values were then compared statistically. As the exposure time and the image resolution increased, the mean value of the fractal dimension decreased, except the case where exposure time was set at 0.01 seconds (alpha = 0.05). The exposure time and image resolution affected the fractal dimension by interaction (p<0.001). When the exposure time was set to either 0.64 seconds or 0.80 seconds, the resulting fractal dimensions were lower, irrespective of image resolution, than at shorter exposure times (alpha = 0.05). The optimal range for exposure time and resolution was determined to be 0.08-0.40 seconds and from 400-1000 dpi, respectively. Adequate exposure time and image resolution is essential for acquiring the fractal dimension using tile-counting method for evaluation of ng tile-counting method for evaluation of the mandible.

193

Effect of exposure time and image resolution on fractal dimension  

Energy Technology Data Exchange (ETDEWEB)

To evaluate the effect of exposure time and image resolution on fractal dimension calculations for determining the optimal range of these two variances. Thirty-one radiographs of the mandibular angle area of sixteen human dry mandibles were taken at different exposure times (0.01, 0.08, 0.16, 0.25, 0.40, 0.64, and 0.80 s). Each radiograph was digitized at 1200 dpi, 8 bit, 256 gray level using a film scanner. We selected an Region of Interest (ROI) that corresponded to the same region as in each radiograph, but the resolution of ROI was degraded to 1000, 800, 600, 500, 400, 300, 200, and 100 dpi. The fractal dimension was calculated by using the tile-counting method for each image, and the calculated values were then compared statistically. As the exposure time and the image resolution increased, the mean value of the fractal dimension decreased, except the case where exposure time was set at 0.01 seconds (alpha = 0.05). The exposure time and image resolution affected the fractal dimension by interaction (p<0.001). When the exposure time was set to either 0.64 seconds or 0.80 seconds, the resulting fractal dimensions were lower, irrespective of image resolution, than at shorter exposure times (alpha = 0.05). The optimal range for exposure time and resolution was determined to be 0.08-0.40 seconds and from 400-1000 dpi, respectively. Adequate exposure time and image resolution is essential for acquiring the fractal dimension using tile-counting method for evaluation of the mandible.

An, Byung Mo; Heo, Min Suk; Lee, Seung Pyo; Lee, Sam Sun; Choi, Soon Chul; Park, Tae Won [College of Dentistry, Seoul National University, Seoul (Korea, Republic of); Kim, Jong Dae [Division of Information and Communication Engineering, Hallym University, Chuncheon (Korea, Republic of)

2002-06-15

194

In vivo real-time, multicolor, quantum dot lymphatic imaging.  

Science.gov (United States)

The lymphatic network is complex and difficult to visualize in real-time in vivo. Moreover, the direction of flow within lymphatic networks is often unpredictable especially in areas with well-developed "watershed" or overlapping lymphatics. Herein, we report a method of in vivo real-time multicolor lymphatic imaging using cadmium-selenium quantum dots (Qdots) with a fluorescence imaging system that enables the simultaneous visualization of up to five distinct lymphatic basins in real-time. Five visually well-distinguishable carboxyl-Qdots (Qdot 545, 565, 585, 605, and 655) were selected and injected subdermally into mice at five different sites, and serially imaged in vivo or in situ under surgery with real-time multicolor lymphatic imaging. In all seven mice, in vivo lymphatic images successfully distinguished all five lymphatic basins with different colors in real-time. These visualizations of lymph node lasted up to at least 7 days. This method could have a considerable potential in lymphatic research for studying the anatomy and flow within the lymphatic system as well as in some limited clinical settings where real-time visible fluorescence could facilitate procedures under surgery or endoscopy. PMID:19536144

Kosaka, Nobuyuki; Ogawa, Mikako; Sato, Noriko; Choyke, Peter L; Kobayashi, Hisataka

2009-12-01

195

Visualization of tumor-induced VEGF expression using in vivo bioluminescence  

Science.gov (United States)

Vascular endothelial growth factor (VEGF) is one of the most potent mediators of both physiologic and pathologic angiogenesis. Normal physiologic induction of VEGF occurs during periods of extreme growth, wound healing, as well as immune inflammatory response. Pathologically, however, VEGF is largely responsible for tumor induced angiogenesis and cell survival. Traditional methods of VEGF expression analysis involve either in vitro studies, or highly invasive in vivo methods. We have developed a unique transgenic mouse model (VGL) that possesses a truncated human VEGF promoter attached to a GFP-Luciferase fusion protein. Incorporating this model with both spontaneous and orthotopically injected tumors allow VEGF promoter activity to be visualized in vivo by luciferase luminescence in response to tumor growth non-invasively and over time. By also utilizing bioluminescent tumor cells, we were able to generate models that identify host, tumor, or combined VEGF promoter activity. Results indicate that tumor tissue is responsible for the majority of VEGF promoter activity during tumor growth. Additional studies into the mechanism by which tumor cells initiate VEGF production will yield much needed insight into tumor survival. In conclusion, we have shown that the VGL bioluminescent mouse model is indeed capable of yielding compelling information on host-tumor interactions.

Faley, Shannon; Crooke, Cornelia; Takahashi, Keiko; Takahashi, Takamune; Jansen, E. Duco

2004-06-01

196

BLProt: prediction of bioluminescent proteins based on support vector machine and relieff feature selection  

OpenAIRE

Abstract 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 repo...

Hazrati Mehrnaz; Pugalenthi Ganesan; Kandaswamy Krishna; Kalies Kai-Uwe; Martinetz Thomas

2011-01-01

197

Pixel timing correction in time-lapsed calcium imaging using point scanning microscopy.  

Science.gov (United States)

In point scanning imaging, data are acquired by sequentially scanning each pixel of a predetermined area. This way of scanning leads to time delays between pixels, especially for lower scanning speed or large scanned areas. Therefore, experiments are often performed at lower framerates in order to ensure a sufficient signal-to-noise ratio, even though framerates above 30 frames per second are technically feasible. For these framerates, we suggest that it becomes crucial to correct the time delay between image pixels prior to analyses. In this paper, we apply temporal interpolation (or pixel timing correction) for calcium imaging in two-photon microscopy as an example of fluorescence imaging. We present and compare three interpolation methods (linear, Lanczos and cubic B-spline). We test these methods on a simulated network of coupled bursting neurons at different framerates. In this network, we introduce a time delay to simulate a scanning by point scanning microscopy. We also assess these methods on actual microscopic calcium imaging movies recorded at usual framerates. Our numerical results suggest that point scanning microscopy imaging introduces statistically significant time delays between image pixels at low frequency. However, we demonstrate that pixel timing correction compensates for these time delays, regardless of the used interpolation method. PMID:25128722

Boiroux, Dimitri; Oke, Yoshihiko; Miwakeichi, Fumikazu; Oku, Yoshitaka

2014-11-30

198

Time-integrated phosphor behavior in gated image intensifier tubes  

Science.gov (United States)

New flow analysis applications of MCP image intensifier tubes require faster image repetition rates. When coupled to CCD readout chips their time-integrated behavior determines the overall system's response concerning the intensity of unwanted ghost images. Previously published experimental data as well as manufacturer's literature provide only time resolved response information. New data for the widely used high-efficiency, slow-decay P20 and P43 phosphors are determined as functions of both exposure (excitation) time and interframe time. Previously reported dependency of decay time being determined solely by the preceding exposure time is not supported by new data. Data herein show an increase of decay time by more than a factor of 100, especially for short excitation times. This is caused by intensity integration on the CCD chip. The P20 shows a very long non-exponential decay. Though being faster during the initial 200 to 500 microsecond(s) , the P20's decay extends over a substantially longer time as compared to the P43 phosphor. This is in clear contradiction to earlier results, which could lead to the expectation of the P20 being more than an order of magnitude faster than P43 for very short exposure times.

Hoess, Paul; Fleder, Karlheinz

2000-11-01

199

Visible light induced ocular delayed bioluminescence as a possible origin of negative afterimage  

CERN Document Server

The delayed luminescence of biological tissues is an ultraweak reemission of absorbed photons after exposure to external monochromatic or white light illumination. Recently, Wang, B\\'okkon, Dai and Antal (Brain Res. 2011) presented the first experimental proof of the existence of spontaneous ultraweak biophoton emission and visible light induced delayed ultraweak photon emission from in vitro freshly isolated rat's whole eye, lens, vitreous humor and retina. Here, we suggest that the photobiophysical source of negative afterimage can also occur within the eye by delayed bioluminescent photons. In other words, when we stare at a colored (or white) image for few seconds, external photons can induce excited electronic states within different parts of the eye that is followed by a delayed reemission of absorbed photons for several seconds. Finally, these reemitted photons can be absorbed by nonbleached photoreceptors that produce a negative afterimage. Although this suggests the photobiophysical source of negativ...

Bokkon, I; Wang, C; Dai, J; Salari, V; Grass, F; Antal, I

2011-01-01

200

A Colour Image Quantization Algorithm for Time-Constrained Applications  

OpenAIRE

Many techniques have been proposed to quantize a digital colour image in order to reduce the representative number of colours to be suitable for presenting on different types of display screens. In addition, the techniques have been used to significantly reduce the amount of image data required to transfer over a communication network. Most of the published techniques are targetted for implementing on a general purpose multitasking computer with low restriction on time and resource utilizatio...

Kurdthongmee, Wattanapong

2005-01-01

201

Investigations on time stability of passive THz imaging  

Science.gov (United States)

Terahertz radiation is within the frequency range from 100 GHz to 10THz. This radiation has specific characteristics in terms of imaging. The radiation is harmless to the human body because the energy transferred by electromagnetic waves in this range of frequencies are very small thus there is no ionization of matter. The development of imaging devices and exploration of new spectral bands is a chance to introduce new equipment for assuring public safety. It has been proved that objects hidden under clothing can be detected and visualized using terahertz (THz) cameras. However, passive THz cameras still offer too low image resolution for objects recognition. In order to determine the properties of terahertz imaging for detection of hidden objects several aspects need to be considered. Taking into account the fact that the image captured by the terahertz camera reflects the spatial distribution of the relative temperature of the observed objects, the effect of the measurement time on the imaging capabilities should be examined. A very important aspect is the influence of the type (material composition) of coating material, as well as the type of an object hidden under clothing (size and material). The purpose of the studies is to investigate the time stability of passive THz imaging on 250 GHz for detection of concealed objects. In the article, we present the measurement setup, the measurement methodology as well as the initial results of measurements with various types of clothing and test objects.

Kowalski, Marcin; Palka, Norbert; Zyczkowski, Marek; Szustakowski, Mieczyslaw

2014-10-01

202

Evidence for light perception in a bioluminescent organ  

OpenAIRE

Here we show that bioluminescent organs of the squid Euprymna scolopes possess the molecular, biochemical, and physiological capability for light detection. Transcriptome analyses revealed expression of genes encoding key visual transduction proteins in light-organ tissues, including the same isoform of opsin that occurs in the retina. Electroretinograms demonstrated that the organ responds physiologically to light, and immunocytochemistry experiments localized multiple proteins of visual tra...

Tong, Deyan; Rozas, Natalia S.; Oakley, Todd H.; Mitchell, Jane; Colley, Nansi J.; Mcfall-ngai, Margaret J.

2009-01-01

203

Real-time Avatar Animation from a Single Image  

OpenAIRE

A real time facial puppetry system is presented. Compared with existing systems, the proposed method requires no special hardware, runs in real time (23 frames-per-second), and requires only a single image of the avatar and user. The user’s facial expression is captured through a real-time 3D non-rigid tracking system. Expression transfer is achieved by combining a generic expression model with synthetically generated examples that better capture person specific characteristics. Performance...

Saragih, Jason M.; Lucey, Simon; Cohn, Jeffrey F.

2011-01-01

204

Relaxation time T1, T2 and proton density images in NMR imaging  

International Nuclear Information System (INIS)

Pure T1, T2 and proton density (?) images can be computed from three or more different NMR images. Computed images can be useful for several reasons: a) they are objective, since they are independent of pulse sequence and scan parameters. b) arbitrary composite images can be synthesized from computed images. c) biochemical information can be obtained from relaxation times, so quantitative diagnosis is possible using T1 and T2 images. For these reasons, several methods of producing computed images have been tried. However, with these methods, there are several practical problems such as large systematic error and long total scan time. This paper describes how several sets of NMR pulse sequences and scan parameters were investigated, keeping total scan time constant, to find which of them gave computed images with best resolution and minimum systematic error for a given scan time. Pulse sequences and scan parameters were optimized to yield minimum variance of computed images, using the law of error propagation, for a given range of T1, T2 and ?. We found that theoretically the combination Inversion Recovery 3 Spin Echo and Saturation Recovery 4 Spin Echo pulse sequence gave the best compromise between scan time and resolution. The effect of slice profile and errors in RF pulses - causes of systematic error - were analyzed in order to find ways to remove or reduce them. Using this method computed T1them. Using this method computed T1, T2 and ? images were obtained for the human head and for various phantoms. Computed values agreed closely with values measured using analytical methods. We conclude from these results that the combination Inversion Recovery 3 Spin Echo and Saturation Recovery 4 Spin Echo pulse sequence gives the best compromise between scan time, resolution and error. (author)

205

Incorporating MRI structural information into bioluminescence tomography: system, heterogeneous reconstruction and in vivo quantification  

Science.gov (United States)

Combining two or more imaging modalities to provide complementary information has become commonplace in clinical practice and in preclinical and basic biomedical research. By incorporating the structural information provided by computed tomography (CT) or magnetic resonance imaging (MRI), the ill poseness nature of bioluminescence tomography (BLT) can be reduced significantly, thus improve the accuracies of reconstruction and in vivo quantification. In this paper, we present a small animal imaging system combining multi-view and multi-spectral BLT with MRI. The independent MRI-compatible optical device is placed at the end of the clinical MRI scanner. The small animal is transferred between the light tight chamber of the optical device and the animal coil of MRI via a guide rail during the experiment. After the optical imaging and MRI scanning procedures are finished, the optical images are mapped onto the MRI surface by interactive registration between boundary of optical images and silhouette of MRI. Then, incorporating the MRI structural information, a heterogeneous reconstruction algorithm based on finite element method (FEM) with L 1 normalization is used to reconstruct the position, power and region of the light source. In order to validate the feasibility of the system, we conducted experiments of nude mice model implanted with artificial light source and quantitative analysis of tumor inoculation model with MDA-231-GFP-luc. Preliminary results suggest the feasibility and effectiveness of the prototype system. PMID:24940545

Zhang, Jun; Chen, Duofang; Liang, Jimin; Xue, Huadan; Lei, Jing; Wang, Qin; Chen, Dongmei; Meng, Ming; Jin, Zhengyu; Tian, Jie

2014-01-01

206

Incorporating MRI structural information into bioluminescence tomography: system, heterogeneous reconstruction and in vivo quantification.  

Science.gov (United States)

Combining two or more imaging modalities to provide complementary information has become commonplace in clinical practice and in preclinical and basic biomedical research. By incorporating the structural information provided by computed tomography (CT) or magnetic resonance imaging (MRI), the ill poseness nature of bioluminescence tomography (BLT) can be reduced significantly, thus improve the accuracies of reconstruction and in vivo quantification. In this paper, we present a small animal imaging system combining multi-view and multi-spectral BLT with MRI. The independent MRI-compatible optical device is placed at the end of the clinical MRI scanner. The small animal is transferred between the light tight chamber of the optical device and the animal coil of MRI via a guide rail during the experiment. After the optical imaging and MRI scanning procedures are finished, the optical images are mapped onto the MRI surface by interactive registration between boundary of optical images and silhouette of MRI. Then, incorporating the MRI structural information, a heterogeneous reconstruction algorithm based on finite element method (FEM) with L 1 normalization is used to reconstruct the position, power and region of the light source. In order to validate the feasibility of the system, we conducted experiments of nude mice model implanted with artificial light source and quantitative analysis of tumor inoculation model with MDA-231-GFP-luc. Preliminary results suggest the feasibility and effectiveness of the prototype system. PMID:24940545

Zhang, Jun; Chen, Duofang; Liang, Jimin; Xue, Huadan; Lei, Jing; Wang, Qin; Chen, Dongmei; Meng, Ming; Jin, Zhengyu; Tian, Jie

2014-06-01

207

Optical imaging simulation using GATE  

International Nuclear Information System (INIS)

The Geant4 Application for Emission Tomography (GATE) is an advanced open source software dedicated to Monte-Carlo (MC) simulations in medical imaging involving photon transportation (positron emission tomography, single photon emission computed tomography, computed tomography) and in particle therapy. In this work, we extend GATE to support simulations of optical imaging such as bioluminescence or fluorescence imaging and validate it against the Monte-Carlo for Multi-Layered media simulation tool. A full simulation set-up for molecular optical imaging (bioluminescence or fluorescence) is implemented and 2D images of the light distribution emitted from a phantom is provided through the GATE software. (authors)

208

Real-time particle image velocimetry based on FPGA technology  

International Nuclear Information System (INIS)

Particle image velocimetry (PIV), based on laser sheet, is a method for image processing and calculation of distributed velocity fields.It is well established as a fluid dynamics measurement tool, being applied to liquid, gases and multiphase flows.Images of particles are processed by means of computationally demanding algorithms, what makes its real-time implementation difficult.The most probable displacements are found applying two dimensional cross-correlation function. In this work, we detail how it is possible to achieve real-time visualization of PIV method by designing an adaptive embedded architecture based on FPGA technology.We show first results of a physical field of velocity calculated by this platform system in a real-time approach.

209

Nonlinear acoustic time reversal imaging using the scaling subtraction method  

International Nuclear Information System (INIS)

Lab experiments have shown that the imaging of nonlinear scatterers using time reversal acoustics can be a very promising tool for early stage damage detection. The potential applications are however limited by the need for an extremely accurate acquisition system. In order to let nonlinear features emerge from the background noise it is necessary to enhance the signal-to-noise ratio as much as possible. A comprehensive analysis to determine the nonlinear components in a recorded time signal, an alternative to those usually adopted (e.g. fast Fourier), is proposed here. The method is based on the nonlinear physical properties of the solution of the wave equation and takes advantage of the deficient system response scalability with the excitation amplitude. In this contribution, we outline the adopted procedure and apply it to a nonlinear time reversal imaging simulation to highlight the advantages with respect to traditional imaging based on a fast Fourier analysis of the recorded signals.

210

Real-time evaluation techniques for real-time image processing hardware  

Science.gov (United States)

Real-time hardware developed for image processing applications such as image enhancement, segmentation, image registration, pattern recognition, etc. can not be thoroughly debugged and analyzed for its performance by using conventional test equipment. To cite an example, the hardware for image registration may be failing intermittently or the registration point may be drifting even when the scene and the sensor are static. There is no way of knowing whether the malfunction is due to input data or any noise glitches. Therefore, for evaluating real-time image processing hardware, it is necessary to acquire image sequence data in real-time and also capture the status of the tracker in real-time. Test equipment like logic analyzer, microprocessor development systems do not have the capability to acquire and store image sequences. General purpose data acquisition systems on the IBM PC compatible computer are not suitable as the data rate required is about 500 kbytes/sec. the design of an interface card for achieving this data rate using IEEE-488 (GPIB) interface is described. Results on the evaluation of image processing hardware using this card are also presented.

Venkateswarlu, Ronda; Rao, C. Arjuna

1992-11-01

211

Evaluation of scintillator afterglow for use in a combined optical and PET imaging tomograph  

Energy Technology Data Exchange (ETDEWEB)

The design of a dual modality imaging system for small animal optical and positron emission tomography imaging (OPET) is underway. Its detector must be capable of imaging high energy {gamma}-rays from PET while also resolving optical wavelength photons from bioluminescence. GSO, high purity GSO, BGO, LSO, LYSO, and LaBr scintillators were investigated for their use in the OPET detector. Of specific interest were scintillators with low afterglow, since afterglow photons in the decay of the larger {gamma}-ray events are indistinguishable from the photons generated by bioluminescence. Samples from these crystals were coupled to a photomultiplier tube (PMT) and produced scintillation light from {gamma}-ray events originating from a positron source. The PMT output was directed to a special signal processing circuit that allowed measurement of single photons at different times in the decay of the scintillation. GSO and BGO exhibited optimal performance for use in the OPET system due to their low afterglow. LSO, LYSO, and LaBr were determined unsuitable for use with the current OPET design due to their significant afterglow components. The effect of the afterglow of GSO on the detection of the bioluminescence signal-to-noise ratio (SNR) was evaluated for the OPET system.

Douraghy, Ali [Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, UCLA School of Medicine, A136, 700 Westwood Plaza, Los Angeles, CA 90095-1770 (United States)]. E-mail: adouraghy@mednet.ucla.edu; Prout, David L. [Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, UCLA School of Medicine, A136, 700 Westwood Plaza, Los Angeles, CA 90095-1770 (United States); Silverman, Robert W. [Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, UCLA School of Medicine, A136, 700 Westwood Plaza, Los Angeles, CA 90095-1770 (United States); Chatziioannou, Arion F. [Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, UCLA School of Medicine, A136, 700 Westwood Plaza, Los Angeles, CA 90095-1770 (United States)

2006-12-20

212

Evaluation of scintillator afterglow for use in a combined optical and PET imaging tomograph  

International Nuclear Information System (INIS)

The design of a dual modality imaging system for small animal optical and positron emission tomography imaging (OPET) is underway. Its detector must be capable of imaging high energy ?-rays from PET while also resolving optical wavelength photons from bioluminescence. GSO, high purity GSO, BGO, LSO, LYSO, and LaBr scintillators were investigated for their use in the OPET detector. Of specific interest were scintillators with low afterglow, since afterglow photons in the decay of the larger ?-ray events are indistinguishable from the photons generated by bioluminescence. Samples from these crystals were coupled to a photomultiplier tube (PMT) and produced scintillation light from ?-ray events originating from a positron source. The PMT output was directed to a special signal processing circuit that allowed measurement of single photons at different times in the decay of the scintillation. GSO and BGO exhibited optimal performance for use in the OPET system due to their low afterglow. LSO, LYSO, and LaBr were determined unsuitable for use with the current OPET design due to their significant afterglow components. The effect of the afterglow of GSO on the detection of the bioluminescence signal-to-noise ratio (SNR) was evaluated for the OPET system

213

Evaluation of scintillator afterglow for use in a combined optical and PET imaging tomograph  

Science.gov (United States)

The design of a dual modality imaging system for small animal optical and positron emission tomography imaging (OPET) is underway. Its detector must be capable of imaging high energy ?-rays from PET while also resolving optical wavelength photons from bioluminescence. GSO, high purity GSO, BGO, LSO, LYSO, and LaBr scintillators were investigated for their use in the OPET detector. Of specific interest were scintillators with low afterglow, since afterglow photons in the decay of the larger ?-ray events are indistinguishable from the photons generated by bioluminescence. Samples from these crystals were coupled to a photomultiplier tube (PMT) and produced scintillation light from ?-ray events originating from a positron source. The PMT output was directed to a special signal processing circuit that allowed measurement of single photons at different times in the decay of the scintillation. GSO and BGO exhibited optimal performance for use in the OPET system due to their low afterglow. LSO, LYSO, and LaBr were determined unsuitable for use with the current OPET design due to their significant afterglow components. The effect of the afterglow of GSO on the detection of the bioluminescence signal-to-noise ratio (SNR) was evaluated for the OPET system.

Douraghy, Ali; Prout, David L.; Silverman, Robert W.; Chatziioannou, Arion F.

2006-12-01

214

D City Transformations by Time Series of Aerial Images  

Science.gov (United States)

Recent photogrammetric applications, based on dense image matching algorithms, allow to use not only images acquired by digital cameras, amateur or not, but also to recover the vast heritage of analogue photographs. This possibility opens up many possibilities in the use and enhancement of existing photos heritage. The research of the original figuration of old buildings, the virtual reconstruction of disappeared architectures and the study of urban development are some of the application areas that exploit the great cultural heritage of photography. Nevertheless there are some restrictions in the use of historical images for automatic reconstruction of buildings such as image quality, availability of camera parameters and ineffective geometry of image acquisition. These constrains are very hard to solve and it is difficult to discover good dataset in the case of terrestrial close range photogrammetry for the above reasons. Even the photographic archives of museums and superintendence, while retaining a wealth of documentation, have no dataset for a dense image matching approach. Compared to the vast collection of historical photos, the class of aerial photos meets both criteria stated above. In this paper historical aerial photographs are used with dense image matching algorithms to realize 3d models of a city in different years. The models can be used to study the urban development of the city and its changes through time. The application relates to the city centre of Verona, for which some time series of aerial photographs have been retrieved. The models obtained in this way allowed, right away, to observe the urban development of the city, the places of expansion and new urban areas. But a more interesting aspect emerged from the analytical comparison between models. The difference, as the Euclidean distance, between two models gives information about new buildings or demolitions. As considering accuracy it is necessary point out that the quality of final observations from model comparison depends on several aspects such as image quality, image scale and marker accuracy from cartography.

Adami, A.

2015-02-01

215

Real-Time Ellipsometry-Based Transmission Ultrasound Imaging  

Energy Technology Data Exchange (ETDEWEB)

Ultrasonic imaging is a valuable tool for non-destructive evaluation and medical diagnosis. Reflection mode is exclusively used for medical imaging, and is most frequently used for nondestructive evaluation (NDE) because of the relative speed of acquisition. Reflection mode imaging is qualitative, yielding little information about material properties, and usually only about material interfaces. Transmission imaging can be used in 3D reconstructions to yield quantitative information: sound speed and attenuation. Unfortunately, traditional scanning methods of acquiring transmission data are very slow, requiring on the order of 20 minutes per image. The sensing of acoustic pressure fields as optical images can significantly speed data acquisition. An entire 2D acoustic pressure field can be acquired in under a second. The speed of data acquisition for a 2D view makes it feasible to obtain multiple views of an object. With multiple views, 3D reconstruction becomes possible. A fast, compact (no big magnets or accelerators), inexpensive, 3D imaging technology that uses no ionizing radiation could be a boon to the NDE and medical communities. 2D transmission images could be examined in real time to give the ultrasonic equivalent of a fluoroscope, or accumulated in such a way as to acquire phase and amplitude data over multiple views for 3D reconstruction (for breast cancer imaging, for example). Composite panels produced for the aircraft and automobile industries could be inspected in near real time, and inspection of attenuating materials such as ceramics and high explosives would be possible. There are currently three optical-readout imaging transmission ultrasound technologies available. One is based on frustrated total internal reflection (FTIR) [1,2], one on Fabry-Perot interferometry [3], and another on critical angle modulation [4]. Each of these techniques has its problems. The FTIR based system cannot currently be scaled to large aperture sizes, the Fabry-Perot system has never been fully implemented for area imaging, and the critical angle modulation system is not sensitive enough for medical imaging. We proposed an entirely new way of using acoustic pressure to modulate a light beam. This new technology should be sensitive enough to be useful for medical imaging and have a large enough aperture to speed acquisition by orders of magnitude over point sampling. Unfortunately, we were unable to bring this technology to fruition.

Kallman, J S; Poco, J F; Ashby, A E

2007-02-14

216

Magneto-optical system for high speed real time imaging  

Science.gov (United States)

A new magneto-optical system has been developed to expand the range of high speed real time magneto-optical imaging. A special source for the external magnetic field has also been designed, using a pump solenoid to rapidly excite the field coil. Together with careful modifications of the cryostat, to reduce eddy currents, ramping rates reaching 3000 T/s have been achieved. Using a powerful laser as the light source, a custom designed optical assembly, and a high speed digital camera, real time imaging rates up to 30 000 frames per seconds have been demonstrated.

Baziljevich, M.; Barness, D.; Sinvani, M.; Perel, E.; Shaulov, A.; Yeshurun, Y.

2012-08-01

217

Cherenkov imaging and timing techniques in astroparticle physics  

International Nuclear Information System (INIS)

Cherenkov techniques are widely used in astroparticle physics experiments. Classical ring imaging has been applied in balloon experiments. Underground Cherenkov detectors also yield ring-like patterns of photomultiplier hits, whereas in deep underwater experiments tracks are reconstructed from the light arrival times at photomultipliers spread over a large volume. Cherenkov air shower detectors either analyze the image of extended showers, or sample the arrival times of the Cherenkov light cone at different points at the earth's surface. This report reviews the various techniques and illustrates them by selected physics results. (orig.)

218

Segmentation of Time-Lapse Images with Focus on Microscopic Images of Cells.  

Czech Academy of Sciences Publication Activity Database

Berlin : Springer-Verlag, 2013 - (Petrosino, A.), s. 71-80 ISBN 978-3-642-41183-0. - (Lecture Notes in Computer Science. Image Processing, Computer Vision , Pattern Recognition, and Graphics. 8157). [International Conference on Image Analysis and Processing. Naples (IT), 11.09.2013-13.09.2013] R&D Projects: GA ?R GA13-29225S Grant ostatní: Grantová agentura UK(CZ) GAUK 914813/2013; GA MŠk(CZ) ED2.1.00/01.0024 Institutional support: RVO:67985556 Keywords : segmentation * time-lapse * microscopy imaging * phase constrast Subject RIV: JD - Computer Applications, Robotics http://library.utia.cas.cz/separaty/2013/ZOI/soukup-segmentation of time-lapse images with focus on microscopic images of cells.pdf

Soukup, Jind?ich; Císa?, P.; Šroubek, Filip

219

Radiofrequency transmission line for bioluminescent Vibrio sp. irradiation  

Science.gov (United States)

We present the study and the analyses of a transmission line for radiofrequency (RF) irradiation of bacteria belonging to Vibrio harveyi-related strain PS1, a bioluminescent bacterium living in symbiosis with many marine organisms. The bioluminescence represents a new biologic indicator which is useful for studying the behaviour of living samples in the presence of RF waves due to the modern communication systems. A suitable transmission line, used as an irradiating cell and tested up to the maximum frequency used by the global system for mobile communications and universal mobile telecommunications system transmissions, was characterized. In this experiment, the RF voltage applied to the transmission line was 1 V. Due to short dimensions of the line and the applied high frequencies, standing waves were produced in addition to progressing waves and the electric field strength varies particularly along the longitudinal direction. The magnetic field map was not strongly linked to the electric one due to the presence of standing waves and of the outgoing irradiation. RF fields were measured by two homemade suitable probes able to diagnostic fields of high frequency. The field measurements were performed without any specimens inside the line. Being our sample made of living matter, the real field was modified and its value was estimated by a simulation code. The bioluminescence experiments were performed only at 900 MHz for two different measured electric fields, 53 and 140 V/m. The light emission was measured right from the beginning and after 7 and 25 h. Under RF irradiation, we found that the bioluminescence activity decreased. Compared with the control sample, the diminution was 6.8% and 44% after 7 and 25 h of irradiation, respectively, both with the low or high field. No changes of the survival factor for all the samples were observed. Besides, to understand the emission processes, we operated the deconvolution of the spectra by two Gaussian curves. The Gaussian peaks were approximately centered at 460 nm and 490 nm. The 490 nm peak was higher than the control one. Under RF, the 490 nm peak decreased compared to the 460 nm one. The decreasing was stronger for the sample in the higher field. The ratio of the emission area of the 490 nm to 460 nm was 5 for the control sample. It decreased up to 1.6 for the samples under RF. The bioluminescence improves the DNA repair by photoreactivation, and there is evidence that photolyase is preferentially activated by blue/violet light. Our finding suggests that RF exposure may stimulate DNA repair by shifting the emission spectra from blue/green (490 nm) to blue/violet (460 nm).

Nassisi, V.; Alifano, P.; Talà, A.; Velardi, L.

2012-07-01

220

BLProt: prediction of bioluminescent proteins based on support vector machine and relieff feature selection  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract 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. The BLProt software is available at http://www.inb.uni-luebeck.de/tools-demos/bioluminescent%20protein/BLProt

Hazrati Mehrnaz

2011-08-01

221

Communication: Time- and space-sliced velocity map electron imaging  

Science.gov (United States)

We develop a new method to achieve slice electron imaging using a conventional velocity map imaging apparatus with two additional components: a fast frame complementary metal-oxide semiconductor camera and a high-speed digitizer. The setup was previously shown to be capable of 3D detection and coincidence measurements of ions. Here, we show that when this method is applied to electron imaging, a time slice of 32 ps and a spatial slice of less than 1 mm thick can be achieved. Each slice directly extracts 3D velocity distributions of electrons and provides electron velocity distributions that are impossible or difficult to obtain with a standard 2D imaging electron detector.

Lee, Suk Kyoung; Lin, Yun Fei; Lingenfelter, Steven; Fan, Lin; Winney, Alexander H.; Li, Wen

2014-12-01

222

Time Domain Terahertz (T-Ray) Subsurface and Structural Imaging  

Science.gov (United States)

The technology, methods, and examples of high speed time domain terahertz (T-Ray) imaging non-destructive examination (NDE) for 2 and 3 dimensional structural and material content characterization are discussed. T-Ray imaging can be utilized for non-contact transmission and/or monostatic reflection inspection of non-conductive materials such as plastics, foam, composites, ceramics, paper, wood and glass. Example subsurface homeland security images of concealed items in baggage and on personnel are shown. We tabulate attenuation and penetration characteristics through a selection of building materials, and demonstrate the ability of T-ray instrumentation to sub-surface image building structures such as wall framing and interior wiring and conduits.

Zimdars, David; White, Jeffrey S.; Stuk, G.; Chernovsky, A.; Fichter, G.; Sucha, G.; Williamson, S.

2007-03-01

223

IMPLEMENTATION OF IMAGE PROCESSING IN REAL TIME CAR PARKING SYSTEM  

Directory of Open Access Journals (Sweden)

Full Text Available Car parking lots are an important object class in many traffic and civilian applications. With the problems of increasing urban trafficcongestion and the ever increasing shortage of space, these car parking lots are needed to be well equipped with automatic parkingInformation and Guidance systems. Goals of intelligent parking lot management include counting the number of parked cars, and identifyingthe available location. This work proposes a new system for providing parking information and guidance using image processing. The proposed system includes counting the number of parked vehicles, and dentifying the stalls available. The system detects cars through images instead of using electronic sensors embedded on the floor. A camera is installed at the entry point of the parking lot. It capturesimage sequences. The image sequences are then analyzed using digital image processing for vehicle detection and according to the status ofvehicle occupancy inside, real time guidance and information is provided to the incoming driver.

SAYANTI BANERJEE,

2011-02-01

224

In vivo bioluminescence imaging of vascular remodeling after stroke  

Directory of Open Access Journals (Sweden)

Full Text Available Thrombolysis remains the only beneficial therapy for ischemic stroke, but is restricted to a short therapeutic window following the infarct. Currently research is focusing on spontaneous regenerative processes during the sub-acute and chronic phase. Angiogenesis, the formation of new blood vessels from pre-existing ones, was observed in stroke patients, correlates with longer survival and positively affects the formation of new neurons. Angiogenesis takes place in the border zones of the infarct, but further insight into the temporal profile is needed to fully apprehend its therapeutic potential and its relevance for neurogenesis and functional recovery. Angiogenesis is a multistep process, involving extracellular matrix degradation, endothelial cell proliferation, and, finally, new vessel formation. Interaction between vascular endothelial growth factor and its receptor 2 (VEGFR2 plays a central role in these angiogenic signaling cascades. In the present study we investigated non-invasively the dynamics of VEGFR2 expression following cerebral ischemia in a mouse model of middle cerebral artery occlusion. We used a transgenic mouse expressing firefly luciferase under the control of the VEGFR2 promotor to non-invasively elucidate the temporal profile of VEGFR2 expression after stroke as a biomarker for VEGF/VEGFR2 signaling. We measured each animal repetitively up to 2 weeks after stroke and found increased VEGFR2 expression starting 3 days after the insult with peak values at 7 days. These were paralleled by increased VEGFR2 protein levels and increased vascular volume in peri-infarct areas at 14 days after the infarct, indicating that signaling via VEGFR2 leads to successful vascular remodeling. This study describes VEGFR2-related signaling is active at least up to 2 weeks after the infarct and results in increased vascular volume. Further, this study presents a novel strategy for the non-invasive evaluation of angiogenesis-based therapies.

Joanna Adamczak

2014-09-01

225

Real-time artifact-free image upscaling.  

Science.gov (United States)

The problem of creating artifact-free upscaled images appearing sharp and natural to the human observer is probably more interesting and less trivial than it may appear. The solution to the problem, often referred to also as "single-image super-resolution," is related both to the statistical relationship between low-resolution and high-resolution image sampling and to the human perception of image quality. In many practical applications, simple linear or cubic interpolation algorithms are applied for this task, but the results obtained are not really satisfactory, being affected by relevant artifacts like blurring and jaggies. Several methods have been proposed to obtain better results, involving simple heuristics, edge modeling, or statistical learning. The most powerful ones, however, present a high computational complexity and are not suitable for real-time applications, while fast methods, even if edge adaptive, are not able to provide artifacts-free images. In this paper, we describe a new upscaling method (iterative curvature-based interpolation) based on a two-step grid filling and an iterative correction of the interpolated pixels obtained by minimizing an objective function depending on the second-order directional derivatives of the image intensity. We show that the constraints used to derive the function are related with those applied in another well-known interpolation method, providing good results but computationally heavy (i.e., new edge-directed interpolation (NEDI). The high quality of the images enlarged with the new method is demonstrated with objective and subjective tests, while the computation time is reduced of one to two orders of magnitude with respect to NEDI so that we were able, using a graphics processing unit implementation based on the nVidia Compute Unified Device Architecture technology, to obtain real-time performances. PMID:21926002

Giachetti, Andrea; Asuni, Nicola

2011-10-01

226

Image domain moving target tracking with advanced image registration and time-differencing techniques  

Science.gov (United States)

Advanced image registration technique with sub-pixel accuracy has been developed and applied for TD (time-differencing) process [1]. The TD process can help to suppress heavy background clutter for improved moving target detection. After processing a CFAR (constant false alarm rate) thresholding detector on the time-differenced image frames, we have developed and applied an image domain moving target tracking (IDMTT) process for robust moving target tracking. The IDMTT process uses a unique location feature by mapping and associating the real moving targets in the previous time-differenced frame with the ghost moving targets in the current time-differenced frame. The accurate location mapping and associating information between time frames is provided by the registration process. Preliminary tests for the IDMTT process are promising. Robust moving target tracking can be achieved even under quite low signal-to-clutter noise-ratio (SCNR = 0.5).

Chen, Hai-Wen; Braunreiter, Denis

2009-05-01

227

Real-Time Air Pollutants Rendering based on Image Processing  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a new method for realistic real-time rendering of air pollutants based on image processing. The air pollutants’ variable density can create many shapes of mist what can add a realistic environment to virtual scene. In order to achieve a realistic effect, we further enhance thus obtained air pollution data getting from monitor in spatial domain. In the proposed method we map the densities of air pollutants to different gray levels, and visualize them by blending those gray levels with background images. The proposed method can also visualize large-scale air pollution data from different viewpoints in real-time and provide the resulting image with any resolution theoretically, which is very important and favorable for the Internet transmission.

Demin Wang

2011-11-01

228

Adaptive digital image processing in real time: First clinical experiences  

International Nuclear Information System (INIS)

The promise of computer image processing has generally not been realized in radiology, partly because the methods advanced to date have been expensive, time-consuming, or inconvenient for clinical use. The authors describe a low-cost system which performs complex image processing operations on-line at video rates. The method uses a combination of unsharp mask subtraction (for low-frequency suppression) and statistical differencing (which adjusts the gain at each point of the image on the basis of its variation from a local mean). The operator interactively adjusts aperture size, contrast gain, background subtraction, and spatial noise reduction. The system is being evaluated for on-line fluoroscopic enhancement, for which phantom measurements and clinical results, including lithotripsy, are presented. When used with a video camera, postprocessing of radiographs was advantageous in a variety of studies, including neonatal chest studies. Real-time speed allows use of the system in the reading room as a ''variable view box.''

229

Time-resolved neutron imaging at ANTARES cold neutron beamline  

CERN Document Server

In non-destructive evaluation with X-rays light elements embedded in dense, heavy (or high-Z) matrices show little contrast and their structural details can hardly be revealed. Neutron radiography, on the other hand, provides a solution for those cases, in particular for hydrogenous materials, owing to the large neutron scattering cross section of hydrogen and uncorrelated dependency of neutron cross section on the atomic number. The majority of neutron imaging experiments at the present time is conducted with static objects mainly due to the limited flux intensity of neutron beamline facilities and sometimes due to the limitations of the detectors. However, some applications require the studies of dynamic phenomena and can now be conducted at several high intensity beamlines such as the recently rebuilt ANTARES beam line at the FRM-II reactor. In this paper we demonstrate the capabilities of time resolved imaging for repetitive processes, where different phases of the process can be imaged simultaneously and...

Tremsin, A S; Tittelmeier, K; Schillinger, B; Schulz, M; Lerche, M; Feller, W B

2015-01-01

230

Software visualization techniques for real-time imaging applications  

Science.gov (United States)

Real-time imaging applications are concerned with efficient and deterministic processing of digital images. These applications are predominantly written using structured programming rather than object-oriented programming with the belief that the former approach has better performance characteristics. Current research shows that this may not be the case and an object-oriented approach may not only result in efficient code but one that is more maintainable and understandable. We look at current techniques for visualizing the code for software applications to determine if they can help predict its qualities such as maintainability, understandability and performance, and suggest ways in which these techniques can be enhanced to meet the specific needs of real-time imaging applications.

Sangwan, R. S.; Ludwig, Robert S.; Neill, Colin J.

2005-02-01

231

In Vivo Real Time Volumetric Synthetic Aperture Ultrasound Imaging  

DEFF Research Database (Denmark)

Synthetic aperture (SA) imaging can be used to achieve real-time volumetric ultrasound imaging using 2-D array transducers. The sensitivity of SA imaging is improved by maximizing the acoustic output, but one must consider the limitations of an ultrasound system, both technical and biological. This paper investigates the in vivo applicability and sensitivity of volumetric SA imaging. Utilizing the transmit events to generate a set of virtual point sources, a frame rate of 25 Hz for a 90° x 90° field-of-view was achieved. Data were obtained using a 3.5 MHz 32 x 32 elements 2-D phased array transducer connected to the experimental scanner (SARUS). Proper scaling is applied to the excitation signal such that intensity levels are in compliance with the U.S. Food and Drug Administration regulations for in vivo ultrasound imaging. The measured Mechanical Index and spatial-peak- temporal-average intensity for parallel beamforming (PB) are 0.83 and 377.5mW/cm2, and for SA are 0.48 and 329.5mW/cm2. A human kidney was volumetrically imaged with SA and PB techniques simultaneously. Two radiologists for evaluation of the volumetric SA were consulted by means of a questionnaire on the level of details perceivable in the beamformed images. The comparison was against PB based on the in vivo data. The feedback from the domain experts indicates that volumetric SA images internal body structures with a better contrast resolution compared to PB at all positions in the entire imaged volume. Furthermore, the autocovariance of a homogeneous area in the in vivo SA data, had 23.5% smaller width at the half of its maximum value compared to PB.

Bouzari, Hamed; Rasmussen, Morten Fischer

2015-01-01

232

Update on time-of-flight PET imaging.  

Science.gov (United States)

Time-of-flight (TOF) PET was initially introduced in the early days of PET. The TOF PET scanners developed in the 1980s had limited sensitivity and spatial resolution, were operated in 2-dimensional mode with septa, and used analytic image reconstruction methods. The current generation of TOF PET scanners has the highest sensitivity and spatial resolution ever achieved in commercial whole-body PET, is operated in fully-3-dimensional mode, and uses iterative reconstruction with full system modeling. Previously, it was shown that TOF provides a gain in image signal-to-noise ratio that is proportional to the square root of the object size divided by the system timing resolution. With oncologic studies being the primary application of PET, more recent work has shown that in modern TOF PET scanners there is an improved tradeoff between lesion contrast, image noise, and total imaging time, leading to a combination of improved lesion detectability, reduced scan time or injected dose, and more accurate and precise lesion uptake measurement. Because the benefit of TOF PET is also higher for heavier patients, clinical performance is more uniform over all patient sizes. PMID:25525181

Surti, Suleman

2015-01-01

233

Ultrasonic Time Reversal and Intermodulation Techniques for Defective Zone Imaging.  

Czech Academy of Sciences Publication Activity Database

Ro?. 19, ?. 2 (2009), s. 13-13. ISSN 1213-3825. [NDT in PROGRESS. 12.11.2009-14.11.2009, Praha] R&D Projects: GA ?R GA106/07/1393 Institutional research plan: CEZ:AV0Z20760514 Keywords : nonlinear elastic wave spectroscopy * time reversal tomography * nonlinear wave modulation * ultrasonic imaging of defects Subject RIV: BI - Acoustics

P?evorovský, Zden?k; Vejvodová, Šárka; Krofta, Josef; P?evorovský, David

2009-01-01

234

De Targets/IMage Energy (TIME) 1.0 Model  

OpenAIRE

Betreft een technische documentatie van de vijf deelmodellen van het Targets/IMage Energy (TIME) 1.0 model. Energy Demand, Liquid Fuel (LF), Gaseous Fuel (GF), Solid Fuel (SF) en Electric Power Generation (EPG) worden gedetailleerd beschreven. Tevens zijn enkele resultaten van modelkalibratie voor de wereld 1900-1990 opgenomen.

de Vries B; Ra, Wijngaart Den

2007-01-01

235

Photon arrival timing with sub-camera exposure time resolution in wide-field time-resolved photon counting imaging.  

Science.gov (United States)

We demonstrate that an ultra-fast CMOS camera combined with a photon counting image intensifier can be used to determine photon arrival times well below the exposure time of the camera. We can obtain a time resolution down to around 1% of the exposure time, i.e. of the order of 40 ns with microsecond exposure times. This is achieved by exploiting the invariant phosphor decay of the image intensifier's phosphor screen: Developing a suitable mathematical framework, we show that the relative intensities of the phosphor decay in successive frames following the photon detection uniquely determine the photon arrival time. This approach opens a way to measuring fast luminescence decays in parallel in many pixels. Possible applications include oxygen and ion concentration imaging using probes with luminescence lifetimes in the range of 100 ns to microseconds. PMID:21164834

Petrášek, Zden?k; Suhling, Klaus

2010-11-22

236

Time-of-flight PET image reconstruction using origin ensembles  

Science.gov (United States)

The origin ensemble (OE) algorithm is a novel statistical method for minimum-mean-square-error (MMSE) reconstruction of emission tomography data. This method allows one to perform reconstruction entirely in the image domain, i.e. without the use of forward and backprojection operations. We have investigated the OE algorithm in the context of list-mode (LM) time-of-flight (TOF) PET reconstruction. In this paper, we provide a general introduction to MMSE reconstruction, and a statistically rigorous derivation of the OE algorithm. We show how to efficiently incorporate TOF information into the reconstruction process, and how to correct for random coincidences and scattered events. To examine the feasibility of LM-TOF MMSE reconstruction with the OE algorithm, we applied MMSE-OE and standard maximum-likelihood expectation-maximization (ML-EM) reconstruction to LM-TOF phantom data with a count number typically registered in clinical PET examinations. We analyzed the convergence behavior of the OE algorithm, and compared reconstruction time and image quality to that of the EM algorithm. In summary, during the reconstruction process, MMSE-OE contrast recovery (CRV) remained approximately the same, while background variability (BV) gradually decreased with an increasing number of OE iterations. The final MMSE-OE images exhibited lower BV and a slightly lower CRV than the corresponding ML-EM images. The reconstruction time of the OE algorithm was approximately 1.3 times longer. At the same time, the OE algorithm can inherently provide a comprehensive statistical characterization of the acquired data. This characterization can be utilized for further data processing, e.g. in kinetic analysis and image registration, making the OE algorithm a promising approach in a variety of applications.

Wülker, Christian; Sitek, Arkadiusz; Prevrhal, Sven

2015-03-01

237

Time-of-flight PET image reconstruction using origin ensembles.  

Science.gov (United States)

The origin ensemble (OE) algorithm is a novel statistical method for minimum-mean-square-error (MMSE) reconstruction of emission tomography data. This method allows one to perform reconstruction entirely in the image domain, i.e. without the use of forward and backprojection operations. We have investigated the OE algorithm in the context of list-mode (LM) time-of-flight (TOF) PET reconstruction. In this paper, we provide a general introduction to MMSE reconstruction, and a statistically rigorous derivation of the OE algorithm. We show how to efficiently incorporate TOF information into the reconstruction process, and how to correct for random coincidences and scattered events. To examine the feasibility of LM-TOF MMSE reconstruction with the OE algorithm, we applied MMSE-OE and standard maximum-likelihood expectation-maximization (ML-EM) reconstruction to LM-TOF phantom data with a count number typically registered in clinical PET examinations. We analyzed the convergence behavior of the OE algorithm, and compared reconstruction time and image quality to that of the EM algorithm. In summary, during the reconstruction process, MMSE-OE contrast recovery (CRV) remained approximately the same, while background variability (BV) gradually decreased with an increasing number of OE iterations. The final MMSE-OE images exhibited lower BV and a slightly lower CRV than the corresponding ML-EM images. The reconstruction time of the OE algorithm was approximately 1.3 times longer. At the same time, the OE algorithm can inherently provide a comprehensive statistical characterization of the acquired data. This characterization can be utilized for further data processing, e.g. in kinetic analysis and image registration, making the OE algorithm a promising approach in a variety of applications. PMID:25668558

Wülker, Christian; Sitek, Arkadiusz; Prevrhal, Sven

2015-03-01

238

Bubble masks for time-encoded imaging of fast neutrons.  

Energy Technology Data Exchange (ETDEWEB)

Time-encoded imaging is an approach to directional radiation detection that is being developed at SNL with a focus on fast neutron directional detection. In this technique, a time modulation of a detected neutron signal is induced-typically, a moving mask that attenuates neutrons with a time structure that depends on the source position. An important challenge in time-encoded imaging is to develop high-resolution two-dimensional imaging capabilities; building a mechanically moving high-resolution mask presents challenges both theoretical and technical. We have investigated an alternative to mechanical masks that replaces the solid mask with a liquid such as mineral oil. Instead of fixed blocks of solid material that move in pre-defined patterns, the oil is contained in tubing structures, and carefully introduced air gaps-bubbles-propagate through the tubing, generating moving patterns of oil mask elements and air apertures. Compared to current moving-mask techniques, the bubble mask is simple, since mechanical motion is replaced by gravity-driven bubble propagation; it is flexible, since arbitrary bubble patterns can be generated by a software-controlled valve actuator; and it is potentially high performance, since the tubing and bubble size can be tuned for high-resolution imaging requirements. We have built and tested various single-tube mask elements, and will present results on bubble introduction and propagation as a function of tubing size and cross-sectional shape; real-time bubble position tracking; neutron source imaging tests; and reconstruction techniques demonstrated on simple test data as well as a simulated full detector system.

Brubaker, Erik; Brennan, James S.; Marleau, Peter; Nowack, Aaron B.; Steele, John; Sweany, Melinda; Throckmorton, Daniel J.

2013-09-01

239

Time-resolved fluorescence imaging in biology and medicine  

Energy Technology Data Exchange (ETDEWEB)

Fluorescence lifetime imaging is a rather new and effective tool that can be used to study complex biological samples, either at microscopic or macroscopic levels. The map of the fluorescence lifetime allows one to discriminate amongst different fluorophores and to achieve valuable insights into the behaviour of emitting molecules, leading to information like local pH, oxygen concentration in cells, etc. Moreover, the distribution in space of any fluorescent marker achievable with this technique can be exploited for diagnostic purposes in medicine. After a brief introduction on the motivations for applying fluorescence lifetime imaging in biology and medicine, the basic principles of this technique will be addressed. Then, the two possible implementations of fluorescence lifetime imaging (i.e. the frequency domain and the time domain methods) will be presented. For this purpose, special attention will be devoted to practical aspects of image acquisition and processing, especially for what concerns the time domain method. Then, the analysis of the state-of-the-art systems will include a brief discussion on new concepts that have recently been introduced in this research field. Finally, two interesting applications of fluorescence lifetime imaging will be presented. The former refers to skin tumour detection and has been successfully applied in a preliminary clinical trial, the latter regards DNA chips reading and has been tested only at laboratory level, yet it has produced promising results for its future implementation in commercial systems. (author)

Cubeddu, R.; Comelli, D.; D' Andrea, C.; Taroni, P.; Valentini, G. [INFM - Dipartimento di Fisica, Politecnico di Milano and IFN - CNR, Milan (Italy)

2002-05-07

240

New bioreactor for in situ simultaneous measurement of bioluminescence and cell density  

Science.gov (United States)

This article presents a new device devoted to the simultaneous measurement of bioluminescence and optical density of a bioluminescent bacterial culture. It features an optoelectronic bioreactor with a fully autoclavable module, in which the bioluminescent bacteria are cultivated, a modulated laser diode dedicated to optical density measurement, and a detection head for the acquisition of both bioluminescence and optical density signals. Light is detected through a bifurcated fiber bundle. This setup allows the simultaneous estimation of the bioluminescence and the cell density of the culture medium without any sampling. The bioluminescence is measured through a highly sensitive photomultiplier unit which has been photometrically calibrated to allow light flux measurements. This was achieved by considering the bioluminescence spectrum and the full optical transmission of the device. The instrument makes it possible to measure a very weak light flux of only a few pW. The optical density is determined through the laser diode and a photodiode using numerical synchronous detection which is based on the power spectrum density of the recorded signal. The detection was calibrated to measure optical density up to 2.5. The device was validated using the Vibrio fischeri bacterium which was cultivated under continuous culture conditions. A very good correlation between manual and automatic measurements processed with this instrument has been demonstrated. Furthermore, the optoelectronic bioreactor enables determination of the luminance of the bioluminescent bacteria which is estimated to be 6×10-5 W sr-1 m-2 for optical density=0.3. Experimental results are presented and discussed.

Picart, Pascal; Bendriaa, Loubna; Daniel, Philippe; Horry, Habib; Durand, Marie-José; Jouvanneau, Laurent; Thouand, Gérald

2004-03-01

241

Rapid Antimicrobial Susceptibility Determination of Uropathogens in Clinical Urine Specimens by Use of ATP Bioluminescence?  

OpenAIRE

We describe the first direct testing of the antimicrobial susceptibilities of bacterial pathogens in human clinical fluid samples by the use of ATP bioluminescence. We developed an ATP bioluminescence assay that eliminates somatic sources of ATP to selectively quantify the bacterial load in clinical urine specimens with a sensitivity of

Ivanc?ic?, Vesna; Mastali, Mitra; Percy, Neil; Gornbein, Jeffrey; Babbitt, Jane T.; Li, Yang; Landaw, Elliot M.; Bruckner, David A.; Churchill, Bernard M.; Haake, David A.

2008-01-01

242

Real-time excitation-enhanced ultrasound contrast imaging.  

Science.gov (United States)

A new nonlinear contrast specific imaging modality, excitation-enhanced imaging (EEI) has been implemented on commercially-available scanners for real-time imaging. This novel technique employs two acoustic fields: a low-frequency, high-intensity ultrasound field (the excitation field) to actively condition contrast microbubbles, and a second lower-intensity regular imaging field applied shortly afterwards to detect enhanced contrast scattering. A Logiq 9 scanner (GE Healthcare, Milwaukee, WI) with a 3.5C curved linear array and an AN2300 digital ultrasound engine (Analogic Corporation, Peabody, MA) with a P4-2 phased array transducer (Philips Medical Systems, Bothell, WA) were modified to perform EEI on a vector-by-vector basis in fundamental and pulse inversion harmonic grayscale modes. Ultrasound contrast microbubbles within an 8 mm vessel embedded in a tissue-mimicking flow phantom (ATS Laboratories, Bridgeport, CT) were imaged in vitro. While video intensities of scattered signals from the surrounding tissue were unchanged, video intensities of echoes from contrast bubbles within the vessel were markedly enhanced. The maximum enhancement achieved was 10.4 dB in harmonic mode (mean enhancement: 6.3 dB; p = 0.0007). In conclusion, EEI may improve the sensitivity of ultrasound contrast imaging, but further work is required to assess the in vivo potential of this new technique. PMID:16231836

Forsberg, Flemming; Shi, William T; Knauer, Michael K; Hall, Anne L; Vecchio, Chris; Bernardi, Richard

2005-04-01

243

Time required to stabilize thermographic images at rest  

Science.gov (United States)

Thermography for scientific research and practical purposes requires a series of procedures to obtain images that should be standardized; one of the most important is the time required for acclimatization in the controlled environment. Thus, the objective of this study was to identify the appropriate acclimatization time in rest to reach a thermal balance on young people skin. Forty-four subjects participated in the study, 18 men (22.3 ± 3.1 years) and 26 women (21.7 ± 2.5 years). Thermographic images were collected using a thermal imager (Fluke®), totaling 44 images over a period of 20 min. The skin temperature (TSK) was measured at the point of examination which included the 0 min, 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20. The body regions of interest (ROI) analyzed included the hands, forearms, arms, thighs, legs, chest and abdomen. We used the Friedman test with post hoc Dunn's in order to establish the time at rest required to obtain a TSK balance and the Mann-Whitney test was used to compare age, BMI, body fat percentage and temperature variations between men and women, considering always a significance level of p young men and women is variable, but for whole body analysis it is recommended at least 10 min for both sexes.

Marins, João Carlos Bouzas; Moreira, Danilo Gomes; Cano, Sergio Piñonosa; Quintana, Manuel Sillero; Soares, Danusa Dias; Fernandes, Alex de Andrade; Silva, Fabrício Sousa da; Costa, Carlos Magno Amaral; Amorim, Paulo Roberto dos Santos

2014-07-01

244

Real time circular tomography system for cardiac imaging  

International Nuclear Information System (INIS)

The authors are developing a focal plane x-ray tomography system capable of creating limited angle tomograms in real-time at rates as high as 60 per second. The intended application of the device is in coronary angiography, where conventional tomographic systems are too slow to capture sharp images of the beating heart. In this report, the authors describe the overall system design and present some of the performance characteristics of three of the sub-system components: image deflection mechanism, x-ray collimator and anti-scatter grid

245

Terahertz time-domain spectroscopy and imaging of artificial RNA  

DEFF Research Database (Denmark)

We use terahertz time-domain spectroscopy (THz-TDS) to measure the far-infrared dielectric function of two artificial RNA single strands, composed of polyadenylic acid (poly-A) and polycytidylic acid (poly-C). We find a significant difference in the absorption between the two types of RNA strands, and we show that we can use this difference to record images of spot arrays of the RNA strands. Under controlled conditions it is possible to use the THz image to distinguish between the two RNA strands. We discuss the requirements to sample preparation imposed by the lack of sharp spectral features in the absorption spectra.

Fischer, Bernd M.; Hoffmann, Matthias

2005-01-01

246

Automatic multimodal real-time tracking for image plane alignment in interventional Magnetic Resonance Imaging  

International Nuclear Information System (INIS)

Interventional magnetic resonance imaging (MRI) aims at performing minimally invasive percutaneous interventions, such as tumor ablations and biopsies, under MRI guidance. During such interventions, the acquired MR image planes are typically aligned to the surgical instrument (needle) axis and to surrounding anatomical structures of interest in order to efficiently monitor the advancement in real-time of the instrument inside the patient's body. Object tracking inside the MRI is expected to facilitate and accelerate MR-guided interventions by allowing to automatically align the image planes to the surgical instrument. In this PhD thesis, an image-based work-flow is proposed and refined for automatic image plane alignment. An automatic tracking work-flow was developed, performing detection and tracking of a passive marker directly in clinical real-time images. This tracking work-flow is designed for fully automated image plane alignment, with minimization of tracking-dedicated time. Its main drawback is its inherent dependence on the slow clinical MRI update rate. First, the addition of motion estimation and prediction with a Kalman filter was investigated and improved the work-flow tracking performance. Second, a complementary optical sensor was used for multi-sensor tracking in order to decouple the tracking update rate from the MR image acquisition rate. Performance of the work-flow was evaluated with both computer simulations and experiments using an MR compatible test bed. Results show a high robustness of the multi-sensor tracking approach for dynamic image plane alignment, due to the combination of the individual strengths of each sensor. (author)

247

Heavy particle timing and imaging with low-pressure MWPCs  

International Nuclear Information System (INIS)

MWPCs operated at gas pressures around 1 torr are shown to have excellent timing and position response for heavily ionizing particles. The avalanche growth process at such conditions is of a double-step nature and is characterized by fast collection times of electrons and positive ions. A substantial spacial distribution of the avalanche, (1-2 mm fwhm), leads to an excellent position resolution even when interpolating between neighbouring wires. Very thin (100-200 ?g/cm2 of polypropylene), fast timing or timing and position sensitive detectors are providing time resolutions of the order of 100-130 ps (fwhm), and position resolutions, with delay-line read-out, of the order of 100 ?m (fwhm). Various detectors of this type, with sizes reaching 80 cm2, operating at counting rates up to 105 c/s.mm2, are used as routine tool for timing and imaging of heavily ionizing particles. (author)

248

Cationic liposomes enhanced firefly bioluminescent assay of adenosine 5'-triphosphate disodium salt.  

Science.gov (United States)

Cationic liposomes containing stearylamine enhanced the intensity of maximum light emission from the firefly luciferin-luciferase reaction with ATP in the range of 1.0 pM up to 5.5 nM. In contrast, the bioluminescent intensities in the presence of anionic and zwitterionic liposomes were about the same as those in water alone. The detection limit for ATP in the presence of cationic liposomes was 1.0 pM in aqueous ATP standard solutions. The sensitivity for ATP was improved by a factor of five times compared to that in water alone. The method was applied to the determination of ATP in Escherichia coli extracts. The sensitivity threshold was presumed to be 340 cells ml-1. PMID:9025909

Kamidate, T; Kinkou, T; Watanabe, H

1997-01-01

249

Prey attraction as a possible function of bioluminescence in the larvae of Pyrearinus termitilluminans (Coleoptera: Elateridae  

Directory of Open Access Journals (Sweden)

Full Text Available Elaterid beetle larvae. Pyrearinus termitilluminans (sp.n., Costa, 1982. live in termite mounds in central Brazil. Each larva produces light in the segment immediately behind its head. Larvae were observed to luminesce only during the first weeks of the rainy season, the same times as the ant and termite alate flights. Alates, apparently attracted to P. termitilluminans larval lights, serve as an important food source for the larvae. The prey-catching and food-storing behavior and the phenomenon of bioluminescence are apparently an evolutionary response by P. termitilluminans larvae to a short, rich pulse of food. Prey attraction as a probable cause for luminescence has been suggested only twice before.

Kent H. Redford

1982-01-01

250

Prey attraction as a possible function of bioluminescence in the larvae of Pyrearinus termitilluminans (Coleoptera: Elateridae)  

Scientific Electronic Library Online (English)

Full Text Available Elaterid beetle larvae. Pyrearinus termitilluminans (sp.n., Costa, 1982.) live in termite mounds in central Brazil. Each larva produces light in the segment immediately behind its head. Larvae were observed to luminesce only during the first weeks of the rainy season, the same times as the ant and t [...] ermite alate flights. Alates, apparently attracted to P. termitilluminans larval lights, serve as an important food source for the larvae. The prey-catching and food-storing behavior and the phenomenon of bioluminescence are apparently an evolutionary response by P. termitilluminans larvae to a short, rich pulse of food. Prey attraction as a probable cause for luminescence has been suggested only twice before.

Kent H., Redford.

251

Real-time digital X-ray subtraction imaging  

International Nuclear Information System (INIS)

A diagnostic anatomical X-ray apparatus comprising a converter and a television camera for converting an X-ray image of a subject into a series of television fields of video signals is described in detail. A digital memory system stores and integrates the video signals over a time interval corresponding to a plurality of successive television fields. The integrated video signals are recovered from storage and fed to a digital or analogue subtractor, the resulting output being displayed on a television monitor. Thus the display represents on-going changes in the anatomical X-ray image. In a modification, successive groups of fields are stored and integrated in three memories, cyclically, and subtractions are performed between successive pieces of integrated signals to provide a display of successive alterations in the X-ray image. For investigations of the heart, the integrating interval should be of the order of one cardiac cycle. (author)

252

A Colour Image Quantization Algorithm for Time-Constrained Applications  

Directory of Open Access Journals (Sweden)

Full Text Available Many techniques have been proposed to quantize a digital colour image in order to reduce the representative number of colours to be suitable for presenting on different types of display screens. In addition, the techniques have been used to significantly reduce the amount of image data required to transfer over a communication network. Most of the published techniques are targetted for implementing on a general purpose multitasking computer with low restriction on time and resource utilizations. The drawback of these techniques relies on the fact that they cannot fulfill the requirement of some applications for real-time constraint and limited resources. In addition, most of the techniques are too complex for hardware realization. In this paper, an algorithm which is more suitable for time critical applications with an additional feature of simplicity to implement on FPGA (Field Programmable Gate Array platforms is proposed and the details of its implementation and experimentation are presented. The dominate point of the proposed algorithm relies on the fact that it utilizes the weighted sum of the nearest distance along the axis under consideration, which is nontrivial to calculate, instead of the squared Euclidean distance to find the axis to split during. Also, the proposed algorithm has proved that by reducing the number of subspaces to be considered during the variance representative value calculation from 8 to 2 subspaces, the quality of quantized images are comparable to the previously proposed approaches. This makes it possible to further speed up the computational time of the quantization algorithm.

Wattanapong KURDTHONGMEE

2005-06-01

253

Time-of-flight imaging of invisibility cloaks  

CERN Document Server

As invisibility cloaking has recently become experimental reality, it is interesting to explore ways to reveal remaining imperfections. In essence, the idea of most invisibility cloaks is to recover the optical path lengths without an object (to be made invisible) by a suitable arrangement around that object. Optical path length is proportional to the time of flight of a light ray or to the optical phase accumulated by a light wave. Thus, time-of-flight images provide a direct and intuitive tool for probing imperfections. Indeed, recent phase-sensitive experiments on the carpet cloak have already made early steps in this direction. In the macroscopic world, time-of-flight images could be measured directly by light detection and ranging (LIDAR). Here, we show calculated time-of-flight images of the conformal Gaussian carpet cloak, the conformal grating cloak, the cylindrical free-space cloak, and of the invisible sphere. All results are obtained by using a ray-velocity equation of motion derived from Fermat's ...

Halimeh, Jad C

2011-01-01

254

Near real-time disturbance detection using satellite image time series  

OpenAIRE

Near real-time monitoring of ecosystem disturbances is critical for rapidly assessing and addressing impacts on carbon dynamics, biodiversity, and socio-ecological processes. Satellite remote sensing enables cost-effective and accurate monitoring at frequent time steps over large areas. Yet, generic methods to detect disturbances within newly captured satellite images are lacking. We propose a multi-purpose time-series-based disturbance detection approach that identifies and models stable his...

Verbesselt, J. P.; Zeileis, A.; Herold, M.

2012-01-01

255

Real time phase diversity advanced image processing and wavefront sensing  

Science.gov (United States)

This paper will describe a state-of-the-art approach to real time wavefront sensing and image enhancement. It will explore Boeing existing technology that realizes a 50 Hz frame rate (with a path to 1 KHz and higher). At this higher rate, Phase diversity will be readily applicable to compensate for distortions of large dynamic bandwidth such as those of the atmosphere. We will describe various challenges in aligning a two-camera phase diversity system. Such configurations make it almost impossible to process the captured images without additional upgrade in the algorithm to account for alignment errors. An example of an error is the relative misalignment of the two images, the "best-focus" and the diversity image where it is extremely hard to maintain alignment to less than a fraction of one pixel. We will show that the algorithm performance increases dramatically when we account for these errors in the phase diversity estimation process. Preliminary evaluation has assessed a NIIRS increase of ~ 3 from the "best-focus" to the enhanced image. Such a performance improvement would greatly increase the operating range (or, equivalently, decrease the weight) of many optical systems.

Dolne, Jean J.; Menicucci, Paul; Miccolis, David; Widen, Ken; Seiden, Harold; Vachss, Frederick; Schall, Harold

2007-09-01

256

Antioxidant assay using genetically engineered bioluminescent Escherichia coli  

Science.gov (United States)

A new antioxidant activity assay based on the reactive oxygen species (ROS)-inducible bacterial strain (E. coli DPD2511) is described. The strain harbors the plasmid pKatG::luxCDABE and responds to hydrogen peroxide treatment by increasing light emission at 490 nm. Antioxidant capacity is evaluated through the ability of an agent to inhibit the hydrogen peroxide-induced bioluminescence of E. coli DPD2511. Applicability of the developed assay in detecting levels of antioxidants in various aqueous plant extracts is demonstrated. The assay was validated against 2,2-diphenylpicrylhydrazyl (DPPH) assay, a known antioxidant assay.

Bartolome, Amelita; Macalino, Bernadette; Pastoral, Ian Lemuel; Sevilla, Fortunato, III

2006-02-01

257

Monitoring Therapeutic Treatments against Burkholderia Infections Using Imaging Techniques.  

Science.gov (United States)

Burkholderia mallei, the etiologic agent of glanders, are Category B select agents with biothreat potential, and yet effective therapeutic treatments are lacking. In this study, we showed that CpG administration increased survival, demonstrating protection in the murine glanders model. Bacterial recovery from infected lungs, liver and spleen was significantly reduced in CpG-treated animals as compared with non-treated mice. Reciprocally, lungs of CpG-treated infected animals were infiltrated with higher levels of neutrophils and inflammatory monocytes, as compared to control animals. Employing the B. mallei bioluminescent strain CSM001 and the Neutrophil-Specific Fluorescent Imaging Agent, bacterial dissemination and neutrophil trafficking were monitored in real-time using multimodal in vivo whole body imaging techniques. CpG-treatment increased recruitment of neutrophils to the lungs and reduced bioluminescent bacteria, correlating with decreased bacterial burden and increased protection against acute murine glanders. Our results indicate that protection of CpG-treated animals was associated with recruitment of neutrophils prior to infection and demonstrated, for the first time, simultaneous real time in vivo imaging of neutrophils and bacteria. This study provides experimental evidence supporting the importance of incorporating optimized in vivo imaging methods to monitor disease progression and to evaluate the efficacy of therapeutic treatment during bacterial infections. PMID:24349761

Mott, Tiffany M; Johnston, R Katie; Vijayakumar, Sudhamathi; Estes, D Mark; Motamedi, Massoud; Sbrana, Elena; Endsley, Janice J; Torres, Alfredo G

2013-06-01

258

Monitoring Therapeutic Treatments against Burkholderia Infections Using Imaging Techniques  

Directory of Open Access Journals (Sweden)

Full Text Available Burkholderia mallei, the etiologic agent of glanders, are Category B select agents with biothreat potential, and yet effective therapeutic treatments are lacking. In this study, we showed that CpG administration increased survival, demonstrating protection in the murine glanders model. Bacterial recovery from infected lungs, liver and spleen was significantly reduced in CpG-treated animals as compared with non-treated mice. Reciprocally, lungs of CpG-treated infected animals were infiltrated with higher levels of neutrophils and inflammatory monocytes, as compared to control animals. Employing the B. mallei bioluminescent strain CSM001 and the Neutrophil-Specific Fluorescent Imaging Agent, bacterial dissemination and neutrophil trafficking were monitored in real-time using multimodal in vivo whole body imaging techniques. CpG-treatment increased recruitment of neutrophils to the lungs and reduced bioluminescent bacteria, correlating with decreased bacterial burden and increased protection against acute murine glanders. Our results indicate that protection of CpG-treated animals was associated with recruitment of neutrophils prior to infection and demonstrated, for the first time, simultaneous real time in vivo imaging of neutrophils and bacteria. This study provides experimental evidence supporting the importance of incorporating optimized in vivo imaging methods to monitor disease progression and to evaluate the efficacy of therapeutic treatment during bacterial infections.

Tiffany M. Mott

2013-05-01

259

Timing and position response of a block detector for fast neutron time-of-flight imaging  

Science.gov (United States)

Our research effort seeks to improve the spatial and timing performance of a block detector made of a pixilated plastic scintillator (EJ-200), first demonstrated as part of Oak Ridge National Laboratory's Advanced Portable Neutron Imaging System. Improvement of the position and time response is necessary to achieve better resolution and contrast in the images of shielded special nuclear material. Time-of-flight is used to differentiate between gamma and different sources of neutrons (e.g., transmission and fission neutrons). Factors limiting the timing and position performance of the neutron detector have been revealed through simulations and measurements. Simulations have suggested that the degradation in the ability to resolve pixels in the neutron detector is due to those interactions occurring near the light guide. The energy deposition within the neutron detector is shown to affect position performance and imaging efficiency. This examination details how energy cuts improve the position performance and degrade the imaging efficiency. Measurements have shown the neutron detector to have a timing resolution of ?=238 ps. The majority of this timing uncertainty is from the depth-of-interaction (DOI) of the neutron which is confirmed by simulations and analytical calculations.

Laubach, M. A.; Hayward, J. P.; Zhang, X.; Cates, J. W.

2014-11-01

260

Real-Time Air Pollutants Rendering based on Image Processing  

OpenAIRE

This paper presents a new method for realistic real-time rendering of air pollutants based on image processing. The air pollutants’ variable density can create many shapes of mist what can add a realistic environment to virtual scene. In order to achieve a realistic effect, we further enhance thus obtained air pollution data getting from monitor in spatial domain. In the proposed method we map the densities of air pollutants to different gray levels, and visualize them by blending those gra...

Demin Wang; Yan Huang; Weitao Li

2011-01-01

261

Germination-Induced Bioluminescence, a Route To Determine the Inhibitory Effect of a Combination Preservation Treatment on Bacterial Spores  

OpenAIRE

In this work, we have used spores of Bacillus subtilis that specifically induce bioluminescence upon initiation of germination as a rapid, real-time monitor of the effects of preservative treatments on germination. Using this tool, we have demonstrated that the combination of mild acidity (pH 5.5 to 5.0), lactic acid (0.5%), and a pasteurization step (90°C for 5 min) results in enhanced inhibition of spore germination compared with the effects of the individual treatments alone. Inhibition b...

Ciarciaglini, Gianni; Hill, Philip J.; Davies, Ken; Mcclure, Peter J.; Kilsby, Derrick; Brown, Martyn H.; Coote, Peter J.

2000-01-01

262

Robust real time extraction of plane segments from time-of-flight camera images  

Science.gov (United States)

We present a method that extracts plane segments from images of a time-of-flight camera. Future driver assistance systems rely on an accurate description of the vehicle's environment. Time-of-flight cameras can be used for environment perception and for the reconstruction of the environment. Since most structures in urban environments are planar, extracted plane segments from single camera images can be used for the creation of a global map. We present a method for real time detection of planar surface structures from time-of-flight camera data. The concept is based on a planar surface segmentation that serves as the fundament for a subsequent global planar surface extraction. The evaluation demonstrates the ability of the described algorithm to detect planar surfaces form depth data of complex scenarios in real time. We compare our methods to state of the art planar surface extraction algorithms.

Dalbah, Yosef; Koltermann, Dirk; Wahl, Friedrich M.

2014-04-01

263

Imaging gene expression in real-time using aptamers  

Energy Technology Data Exchange (ETDEWEB)

Signal transduction pathways are usually activated by external stimuli and are transient. The downstream changes such as transcription of the activated genes are also transient. Real-time detection of promoter activity is useful for understanding changes in gene expression, especially during cell differentiation and in development. A simple and reliable method for viewing gene expression in real time is not yet available. Reporter proteins such as fluorescent proteins and luciferase allow for non-invasive detection of the products of gene expression in living cells. However, current reporter systems do not provide for real-time imaging of promoter activity in living cells. This is because of the long time period after transcription required for fluorescent protein synthesis and maturation. We have developed an RNA reporter system for imaging in real-time to detect changes in promoter activity as they occur. The RNA reporter uses strings of RNA aptamers that constitute IMAGEtags (Intracellular MultiAptamer GEnetic tags), which can be expressed from a promoter of choice. The tobramycin, neomycin and PDC RNA aptamers have been utilized for this system and expressed in yeast from the GAL1 promoter. The IMAGEtag RNA kinetics were quantified by RT-qPCR. In yeast precultured in raffinose containing media the GAL1 promoter responded faster than in yeast precultured in glucose containing media. IMAGEtag RNA has relatively short half-life (5.5 min) in yeast. For imaging, the yeast cells are incubated with their ligands that are labeled with fluorescent dyes. To increase signal to noise, ligands have been separately conjugated with the FRET (Förster resonance energy transfer) pairs, Cy3 and Cy5. With these constructs, the transcribed aptamers can be imaged after activation of the promoter by galactose. FRET was confirmed with three different approaches, which were sensitized emission, acceptor photobleaching and donor lifetime by FLIM (fluorescence lifetime imaging microscopy). Real-time transcription was measured by FLIM-FRET, which was detected by the decrease in donor lifetime resulting from ligand binding to IMAGEtags that were newly synthesized from the activated GAL1 promoter. The FRET signal was specific for transcribed IMAGEtags.

Shin, Il Chung

2011-12-13

264

Imaging gene expression in real-time using aptamers  

Energy Technology Data Exchange (ETDEWEB)

Signal transduction pathways are usually activated by external stimuli and are transient. The downstream changes such as transcription of the activated genes are also transient. Real-time detection of promoter activity is useful for understanding changes in gene expression, especially during cell differentiation and in development. A simple and reliable method for viewing gene expression in real time is not yet available. Reporter proteins such as fluorescent proteins and luciferase allow for non-invasive detection of the products of gene expression in living cells. However, current reporter systems do not provide for real-time imaging of promoter activity in living cells. This is because of the long time period after transcription required for fluorescent protein synthesis and maturation. We have developed an RNA reporter system for imaging in real-time to detect changes in promoter activity as they occur. The RNA reporter uses strings of RNA aptamers that constitute IMAGEtags (Intracellular MultiAptamer GEnetic tags), which can be expressed from a promoter of choice. The tobramycin, neomycin and PDC RNA aptamers have been utilized for this system and expressed in yeast from the GAL1 promoter. The IMAGEtag RNA kinetics were quantified by RT-qPCR. In yeast precultured in raffinose containing media the GAL1 promoter responded faster than in yeast precultured in glucose containing media. IMAGEtag RNA has relatively short half-life (5.5 min) in yeast. For imaging, the yeast cells are incubated with their ligands that are labeled with fluorescent dyes. To increase signal to noise, ligands have been separately conjugated with the FRET (Förster resonance energy transfer) pairs, Cy3 and Cy5. With these constructs, the transcribed aptamers can be imaged after activation of the promoter by galactose. FRET was confirmed with three different approaches, which were sensitized emission, acceptor photobleaching and donor lifetime by FLIM (fluorescence lifetime imaging microscopy). Real-time transcription was measured by FLIM-FRET, which was detected by the decrease in donor lifetime resulting from ligand binding to IMAGEtags that were newly synthesized from the activated GAL1 promoter. The FRET signal was specific for transcribed IMAGEtags.

Shin, Il Chung [Ames Laboratory

2012-11-02

265

Partial scene reconstruction using Time-of-Flight imaging  

Science.gov (United States)

This paper is devoted to generating the coordinates of partial 3D points in scene reconstruction via time of flight (ToF) images. Assuming the camera does not move, only the coordinates of the points in images are accessible. The exposure time is two trillionths of a second and the synthetic visualization shows that the light moves at half a trillion frames per second. In global light transport, direct components signify that the light is emitted from a light point and reflected from a scene point only once. Considering that the camera and source light point are supposed to be two focuses of an ellipsoid and have a constant distance at a time, we take into account both the constraints: (1) the distance is the sum of distances which light travels between the two focuses and the scene point; and (2) the focus of the camera, the scene point and the corresponding image point are in a line. It is worth mentioning that calibration is necessary to obtain the coordinates of the light point. The calibration can be done in the next two steps: (1) choose a scene that contains some pairs of points in the same depth, of which positions are known; and (2) take the positions into the last two constraints and get the coordinates of the light point. After calculating the coordinates of scene points, MeshLab is used to build the partial scene model. The proposed approach is favorable to estimate the exact distance between two scene points.

Zhang, Yuchen; Xiong, Hongkai

2014-11-01

266

Multiplexed amino acid array utilizing bioluminescent Escherichia coli auxotrophs.  

Science.gov (United States)

We describe a novel multiplex "amino acid array" for simultaneously quantifying different amino acids based on the rapid growth of amino acid auxotrophic E. coli. First, we constructed genetically engineered amino acid auxotrophs of E. coli containing a bioluminescence reporter gene, yielding concomitant luminescence as a response to cell growth, and then immobilized the reporter cells within individual agarose of respective wells in a 96-well plate serving as a mimic of a biochip. Using the amino acid array, we were able to determine quantitatively the concentrations of 16 amino acids in biological fluid by simply measuring bioluminescent signals from the immobilized cells within 4 h without pre- and post-treatment. The clinical utility of this method was verified by quantifying different amino acids in dried blood spot specimens from clinical samples for the diagnosis of metabolic diseases of newborn babies. This method serves as a convenient route to the rapid and simultaneous analysis of multiple amino acids from complex biological fluids and represents a new analytical paradigm that can replace conventional, yet laborious methods currently in use. PMID:20405822

Kim, Moon Il; Yu, Byung Jo; Woo, Min-Ah; Cho, Daeyeon; Dordick, Jonathan S; Cho, June Hyoung; Choi, Byung-Ok; Park, Hyun Gyu

2010-05-15

267

Real-time photoacoustic imaging system for burn diagnosis.  

Science.gov (United States)

We have developed a real-time (8 to 30 fps) photoacoustic (PA) imaging system with a linear-array transducer for burn depth assessment. In this system, PA signals originating from blood in the noninjured tissue layer located under the injured tissue layer are detected and imaged. A compact home-made high-repetition-rate (500 Hz) 532-nm fiber laser was incorporated as a light source. We used an alternating arrangement for the fibers and sensor elements in the probe, which improved the signal-to-noise ratio, reducing the required laser energy power for PA excitation. This arrangement also enabled a hand-held light-weight probe design. A phantom study showed that thin light absorbers embedded in the tissue-mimicking scattering medium at depths >3 mm can be imaged with high contrast. The maximum error for depth measurement was 140 ?m. Diagnostic experiments were performed for rat burn models, including superficial dermal burn, deep dermal burn, and deep burn models. Injury depths (zones of stasis) indicated by PA imaging were compared with those estimated by histological analysis, showing discrepancies 200 ?m. The system was also used to monitor the healing process of a deep dermal burn. The results demonstrate the potential usefulness of the present system for clinical burn diagnosis. PMID:25127338

Ida, Taiichiro; Kawaguchi, Yasushi; Kawauchi, Satoko; Iwaya, Keiichi; Tsuda, Hitoshi; Saitoh, Daizoh; Sato, Shunichi; Iwai, Toshiaki

2014-08-01

268

Real-time Image Generation for Compressive Light Field Displays  

International Nuclear Information System (INIS)

With the invention of integral imaging and parallax barriers in the beginning of the 20th century, glasses-free 3D displays have become feasible. Only today—more than a century later—glasses-free 3D displays are finally emerging in the consumer market. The technologies being employed in current-generation devices, however, are fundamentally the same as what was invented 100 years ago. With rapid advances in optical fabrication, digital processing power, and computational perception, a new generation of display technology is emerging: compressive displays exploring the co-design of optical elements and computational processing while taking particular characteristics of the human visual system into account. In this paper, we discuss real-time implementation strategies for emerging compressive light field displays. We consider displays composed of multiple stacked layers of light-attenuating or polarization-rotating layers, such as LCDs. The involved image generation requires iterative tomographic image synthesis. We demonstrate that, for the case of light field display, computed tomographic light field synthesis maps well to operations included in the standard graphics pipeline, facilitating efficient GPU-based implementations with real-time framerates.

269

High-temperature real-time ultrasonic imaging  

International Nuclear Information System (INIS)

Ultrasonic instrumentation capable of real-time imaging of materials at temperatures up to 2880C (5900F) is described. The research and development of this unique instrumentation was sponsored by the Electric Power Research Institute of Palo Alto, California, for use in nuclear power plants. The instrumentation developed will permit continuous surveillance of piping while the power plant is in operation. The instrumentation utilizes a combination of high-temperature materials to fabricate a unique piezoelectric transmitter and a high-temperature electromagnetic acoustic transducer (EMAT). The high-temperature EMAT operates at 2.5 MHz, which is well above preceding models of about 800 kHz. Use of unique high-temperature materials to permit scanning of material volume is combined with an imaging system to allow time-lapse image information. This paper traces the theory and describes material properties of interest and reports on test results for a development system that has been in continuous operation on a field test site for two years. Future applications and development plans are outlined

270

Real-time Image Generation for Compressive Light Field Displays  

Science.gov (United States)

With the invention of integral imaging and parallax barriers in the beginning of the 20th century, glasses-free 3D displays have become feasible. Only today—more than a century later—glasses-free 3D displays are finally emerging in the consumer market. The technologies being employed in current-generation devices, however, are fundamentally the same as what was invented 100 years ago. With rapid advances in optical fabrication, digital processing power, and computational perception, a new generation of display technology is emerging: compressive displays exploring the co-design of optical elements and computational processing while taking particular characteristics of the human visual system into account. In this paper, we discuss real-time implementation strategies for emerging compressive light field displays. We consider displays composed of multiple stacked layers of light-attenuating or polarization-rotating layers, such as LCDs. The involved image generation requires iterative tomographic image synthesis. We demonstrate that, for the case of light field display, computed tomographic light field synthesis maps well to operations included in the standard graphics pipeline, facilitating efficient GPU-based implementations with real-time framerates.

Wetzstein, G.; Lanman, D.; Hirsch, M.; Raskar, R.

2013-02-01

271

Time-Resolved Near-Edge Coherent Diffractive Imaging  

Science.gov (United States)

Coherent diffractive imaging (CDI) with x-rays is a well-established technique that provides structural information beyond the limitations of optical microscopy. Free electron lasers provide ultrashort x-ray pulses with sufficiently high peak brightness to facilitate single-shot imaging and the extension of CDI into the time-domain. Recent progress in the generation of spatially coherent ultrashort x-ray pulses by high harmonic generation (HHG) using tabletop lasers lead to the emergence of a new field of laboratory-based CDI. While a relatively low photon flux and limited photon energies result in lower imaging resolution compared to x-ray studies at large-scale facilities, the significantly greater availability makes laboratory-based experiments well suited for developing new CDI techniques. We present a new apparatus for CDI, which provides ultrashort XUV pulses with tunable photon energies. By implementing a monochromator in a HHG-based CDI setup, the photon energy can be tuned to the inner-shell absorption edges of different elements in the sample. The wavelength-dependence of the x-ray optical constants close to the resonances facilitates to exploit the element selectivity and chemical sensitivity of x-ray transitions in time-domain CDI experiments.

Weise, Fabian; Neumark, Daniel; Leone, Stephen R.; Gessner, Oliver

2012-02-01

272

Compound image compression for real-time computer screen image transmission.  

Science.gov (United States)

We present a compound image compression algorithm for real-time applications of computer screen image transmission. It is called shape primitive extraction and coding (SPEC). Real-time image transmission requires that the compression algorithm should not only achieve high compression ratio, but also have low complexity and provide excellent visual quality. SPEC first segments a compound image into text/graphics pixels and pictorial pixels, and then compresses the text/graphics pixels with a new lossless coding algorithm and the pictorial pixels with the standard lossy JPEG, respectively. The segmentation first classifies image blocks into picture and text/graphics blocks by thresholding the number of colors of each block, then extracts shape primitives of text/graphics from picture blocks. Dynamic color palette that tracks recent text/graphics colors is used to separate small shape primitives of text/graphics from pictorial pixels. Shape primitives are also extracted from text/graphics blocks. All shape primitives from both block types are losslessly compressed by using a combined shape-based and palette-based coding algorithm. Then, the losslessly coded bitstream is fed into a LZW coder. Experimental results show that the SPEC has very low complexity and provides visually lossless quality while keeping competitive compression ratios. PMID:16121449

Lin, Tony; Hao, Pengwei

2005-08-01

273

Image-Based Learning Approach Applied to Time Series Forecasting  

Scientific Electronic Library Online (English)

Full Text Available En este trabajo se presenta un nuevo enfoque para obtener información de una serie de tiempo. Para implementar esta nueva técnica, se ha definido una nueva representación de los datos de entrada de una serie de tiempo. Esta nueva representación está basada en la información obtenida mediante la divi [...] sión del eje de la imagen de la serie de tiempo en cajas. La diferencia entre esta nueva técnica de representación de datos y la forma clásica, se basa en que no es dependiente del tiempo. La nueva representación se ha implementado en una nueva técnica denominada Técnica de Aprendizaje Basada en la Imagen (IBLA por su siglas en inglés) y por medio de un mecanismo probabilístico, esta técnica se aplica al muy interesante problema de predicción en una serie de tiempo. Los resultados experimentales indican que usando esta metodología es posible obtener mejores resultados que los obtenidos por medio de Redes Neuronales Artificiales y Máquinas de Soporte Vectorial. Abstract in english In this paper, a new learning approach based on time-series image information is presented. In order to implement this new learning technique, a novel time-series input data representation is also defined. This input data representation is based on information obtained by image axis division into bo [...] xes. The difference between this new input data representation and the classical is that this technique is not time-dependent. This new information is implemented in the new Image-Based Learning Approach (IBLA) and by means of a probabilistic mechanism this learning technique is applied to the interesting problem of time series forecasting. The experimental results indicate that by using the methodology proposed in this article, it is possible to obtain better results than with the classical techniques such as artificial neuronal networks and support vector machines.

K., Ramírez-Amáro; J. C., Chimal-Eguía.

2012-12-01

274

A portable, real-time, holographic system for imaging flaws  

International Nuclear Information System (INIS)

In this paper the authors describe a portable system that can be used in a field situation. Image reconstruction is accomplished mathematically in near real-time, and the image displayed in a variety of formats. The system utilizes a special purpose microcomputer designed around the 16-bit Intel 8086 and 8087 microprocessor chips. The system fits into three suitcase containers that can be shipped as excess baggage on most air-lines. The system has been tested on pressure vessel and piping samples containing machined and natural flaws, and has also been used in the field to inspect a weld in the steam generator shell of a nuclear power plant. The theory, implementation, and experimental results are presented

275

Satellite image time series simulation for environmental monitoring  

Science.gov (United States)

The performance of environmental monitoring heavily depends on the availability of consecutive observation data and it turns out an increasing demand in remote sensing community for satellite image data in the sufficient resolution with respect to both spatial and temporal requirements, which appear to be conflictive and hard to tune tradeoffs. Multiple constellations could be a solution if without concerning cost, and thus it is so far interesting but very challenging to develop a method which can simultaneously improve both spatial and temporal details. There are some research efforts to deal with the problem from various aspects, a type of approaches is to enhance the spatial resolution using techniques of super resolution, pan-sharpen etc. which can produce good visual effects, but mostly cannot preserve spectral signatures and result in losing analytical value. Another type is to fill temporal frequency gaps by adopting time interpolation, which actually doesn't increase informative context at all. In this paper we presented a novel method to generate satellite images in higher spatial and temporal details, which further enables satellite image time series simulation. Our method starts with a pair of high-low resolution data set, and then a spatial registration is done by introducing LDA model to map high and low resolution pixels correspondingly. Afterwards, temporal change information is captured through a comparison of low resolution time series data, and the temporal change is then projected onto high resolution data plane and assigned to each high resolution pixel referring the predefined temporal change patterns of each type of ground objects to generate a simulated high resolution data. A preliminary experiment shows that our method can simulate a high resolution data with a good accuracy. We consider the contribution of our method is to enable timely monitoring of temporal changes through analysis of low resolution images time series only, and usage of costly high resolution data can be reduced as much as possible, and it presents an efficient solution with great cost performance to build up an economically operational monitoring service for environment, agriculture, forest, land use investigation, and other applications.

Guo, Tao

2014-11-01

276

Modular Image Processor: an efficient chip set for real-time image processing  

Science.gov (United States)

With the breakthrough achieved in both memory capacities and very large scale integration a large field of sophisticated algorithms can now be implemented in real time or video rate. This is especially true for low level operations which are taking into account the video image itself. At this level most of the operations can be carried out using a restricted group of basic functions. This has led to the realisation of a coherent VLSI chip set named MW (Modular Image Processor) carried out in the framework of a EUREKA project. The methodology which has ruled the design the resulting chip set description as well as one of its applications are presented

Waldburger, Hughes; Dufour, Jean-Yves; Concordel, Gilles

1990-09-01

277

Ready for prime time? Dual tracer PET and SPECT imaging.  

Science.gov (United States)

Dual isotope single photon emission computed tomography (SPECT) and dual tracer positron emission tomography (PET) imaging have great potential in clinical and molecular applications in the pediatric as well as the adult populations in many areas of brain, cardiac, and oncologic imaging as it allows the exploration of different physiological and molecular functions (e.g., perfusion, neurotransmission, metabolism, apoptosis, angiogenesis) under the same physiological and physical conditions. This is crucial when the physiological functions studied depend on each other (e.g., perfusion and metabolism) hence requiring simultaneous assessment under identical conditions, and can reduce greatly the quantitation errors associated with physical factors that can change between acquisitions (e.g., human subject or animal motion, change in the attenuation map as a function of time) as is detailed in this editorial. The clinical potential of simultaneous dual isotope SPECT, dual tracer PET and dual SPECT/PET imaging are explored and summarized. In this issue of AJNMMI (http://www.ajnmmi.us), Chapman et al. explore the feasibility of simultaneous and sequential SPECT/PET imaging and conclude that down-scatter and crosstalk from 511 keV photons preclude obtaining useful SPECT information in the presence of PET radiotracers. They report on an alternative strategy that consists of performing sequential SPECT and PET studies in hybrid microPET/SPECT/CT scanners, now widely available for molecular imaging. They validate their approach in a phantom consisting of a 96-well plate with variable (99m)Tc and (18)F concentrations and illustrate the utility of such approaches in two sequential SPECT-PET/CT studies that include (99m)Tc-MAA/(18)F-NaF and (99m)Tc-Pentetate/(18)F-NaF. These approaches will need to be proven reproducible, accurate and robust to variations in the experimental conditions before they can be accepted by the molecular imaging community and be implemented in routine molecular microPET and microSPECT explorations. Although currently not accepted as standard procedures in the molecular imaging community, such approaches have the potential to open the way to new SPECT/PET explorations that allow studying molecular mechanisms and pathways in the living animal under similar physiological conditions. Although still premature for the clinical setting, these approaches can be extended to clinical research once proven accurate and precise in vivo in small and large animal models. PMID:23145358

Fakhri, Georges El

2012-01-01

278

Recursive time-varying filter banks for subband image coding  

Science.gov (United States)

Filter banks and wavelet decompositions that employ recursive filters have been considered previously and are recognized for their efficiency in partitioning the frequency spectrum. This paper presents an analysis of a new infinite impulse response (IIR) filter bank in which these computationally efficient filters may be changed adaptively in response to the input. The filter bank is presented and discussed in the context of finite-support signals with the intended application in subband image coding. In the absence of quantization errors, exact reconstruction can be achieved and by the proper choice of an adaptation scheme, it is shown that IIR time-varying filter banks can yield improvement over conventional ones.

Smith, Mark J. T.; Chung, Wilson C.

1992-01-01

279

Imaging cell biology in live animals: Ready for prime time  

Science.gov (United States)

Time-lapse fluorescence microscopy is one of the main tools used to image subcellular structures in living cells. Yet for decades it has been applied primarily to in vitro model systems. Thanks to the most recent advancements in intravital microscopy, this approach has finally been extended to live rodents. This represents a major breakthrough that will provide unprecedented new opportunities to study mammalian cell biology in vivo and has already provided new insight in the fields of neurobiology, immunology, and cancer biology. PMID:23798727

Porat-Shliom, Natalie; Amornphimoltham, Panomwat

2013-01-01

280

Time-resolved gigahertz acoustic wave imaging at arbitrary frequencies.  

Science.gov (United States)

We describe a way to generate and detect arbitrary frequency components in time-resolved surface acoustic wave imaging based on optical pumping and probing with a periodic light source. The detailed theory of the technique, based on beam modulation and Fourier analysis, for a variety of possible experimental configurations is presented, followed by experimental data for a glass substrate covered with a thin gold film. We show how the acoustic dispersion relation can be obtained to arbitrary frequency resolution, not limited by the laser pulse repetition rate. PMID:25768824

Matsuda, Osamu; Kaneko, Shogo; Wright, Oliver; Tomoda, Motonobu

2015-03-01

281

Comparison of Optimization Techniques for Mutual Information based Real Time Image Registration  

OpenAIRE

Image registration is the process of aligning two or more images of the same scene. A direct image registration approach uses Mutual Information (MI) as an image alignment. Mutual Information is a measure of the similarity of different images. It is robust, accurate and real-time for the both monomodal and multimodal images. It has the ability to perform robust alignment with illumination changes, multi-modality and occlusions. This method also helps to produce accurate image registration res...

Renu Maria Mathews, D. Raveena Judie Dolly

2013-01-01

282

Results from laboratory tests of the two-dimensional Time-Encoded Imaging System.  

Energy Technology Data Exchange (ETDEWEB)

A series of laboratory experiments were undertaken to demonstrate the feasibility of two dimensional time-encoded imaging. A prototype two-dimensional time encoded imaging system was designed and constructed. Results from imaging measurements of single and multiple point sources as well as extended source distributions are presented. Time encoded imaging has proven to be a simple method for achieving high resolution two-dimensional imaging with potential to be used in future arms control and treaty verification applications.

Marleau, Peter; Brennan, James S.; Brubaker, Erik; Gerling, Mark D; Le Galloudec, Nathalie Joelle

2014-09-01

283

Yearlong moored bioluminescence and current data at KM3NeT neutrino telescope sites in the deep Ionian Sea  

Science.gov (United States)

Yearlong observations are presented using stand-alone small optical sensors and current meters in the deep Ionian Sea, E-Mediterranean. At two future neutrino telescope sites, off Sicily (I) and off Peloponessos (Gr), we deployed 2500-3000 m long mooring lines with oceanographic instrumentation. At about 150 m above the sea-floor, a glass sphere was mounted to each line holding two 3?-diameter photo-multiplier-tubes 'PMTs' in opposing directions for a first deep-sea test. Due to technical problems the background optical count rate could not be well established. Here, the focus is on the variations with time of bioluminescence bursts and their correlation with currents. Spectral analysis demonstrates that the PMT data best resemble those of horizontal currents (kinetic energy), significantly peaking at near-inertial, sub-inertial mesoscale and (Gr only) at tidal frequencies. Out-of-phase differences between signals from opposing PMTs in the same optical unit indicate impacts of bioluminescent organisms as a function of current direction, rather than a bacterial glow constant with time.

van Haren, Hans; de Jong, Maarten; Kooijman, Paul

2015-07-01

284

Real Time Circular Tomography System For Cardiac Imaging  

Science.gov (United States)

We have been developing a focal plane x-ray tomography system that will be capable of creating limited angle tomograms in real-time at rates as high as 60 per second. The intended application of the device would be in coronary angiography, where conventional tomographic systems are too slow to capture sharp images of the beating heart. We first reported on this system development three years ago. Since that time, we have been constructing and testing sub-system components while awaiting the completion of the design, construction and testing of the "Tomotron" x-ray tube, which is being manufactured by the Eimac Division of Varian Corporation. We anticipate that the x-ray tube will be ready for integration into the tomography system this spring. In this report, we would like to describe the overall system design and present some of the performance characteristics of three of the sub-system components: image deflection mechanism, x-ray collimator and anti-scatter grid.

Kruger, Robert A.; Smith, Steven W.

1988-06-01

285

An objective method to assess bioluminescent properties of selected bacterial strains  

Directory of Open Access Journals (Sweden)

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.

Bo?ena Danyluk

2007-12-01

286

Effect of irradiation on detection of bacteria in dehydrated vegetables with ATP bioluminescence assay  

International Nuclear Information System (INIS)

ATP bioluminescence intensity of 4 kinds of irradiated dehydrated vegetables was inconsistent with the bacteria number, the reasons were investigated in this paper. Results showed that irradiation had little effect on background luminescence, and there was no effect on luciferase-luminous system. When irradiation killed the bacteria, the ATPase activity also decreased. As a result, the ATP content in bacteria didn't decreased with the killed of bacteria, which contributed to the increase of free ATP in ATP extract and finally led to the disagreement between the bioluminescence intensity and the actual number of bacteria. When the free ATP in the dehydrated vegetable was removed, the bioluminescence intensity of ATP extract was consistent with the actual number of bacteria in irradiated dehydrated vegetable and ATP bioluminescence technology could be used in bacteria detection of irradiated samples. (authors)

287

Bacterial bioluminescence response to long-term exposure to reverse osmosis treated effluents from dye industries.  

Science.gov (United States)

The bacterial bioluminescence assay is one of the novel means for toxicity detection. The bioluminescence response of 2 marine bioluminescent bacteria was tested upon their long-term exposure to 9 different reverse osmosis (RO) rejects with varying chemical composition sampled from various dye industries. Bioluminescent bacteria were cultured in the RO reject samples, at different concentrations, and their growth rate and luminescence was measured for 24 h. The RO reject samples caused sublethal effects upon exposure and retarded the growth of bacteria, confirming their toxic nature. Further, continuation of the exposure showed that the initial luminescence, though reduced, recovered and increased beyond the control cultures irrespective of cell density, and finally decreased once again. The present study emphasizes the need of evolving a long-term exposure assay and shows that the method followed in this study is suitable to evaluate the toxicants that exert delayed toxicity, using lower concentrations of toxicants as well as coloured samples. PMID:25302530

Ravindran, J; Manikandan, B; Shirodkar, P V; Francis, K X; Mani Murali, R; Vethamony, P

2014-10-01

288

Global near real-time disturbance monitoring using MODIS satellite image time series  

Science.gov (United States)

Global disturbance monitoring in forested ecosystems is critical to retrieve information on carbon storage dynamics, biodiversity, and other socio-ecological processes. Satellite remote sensing provides a means for cost-effective monitoring at frequent time steps over large areas. However, for information about current change processes, it is required to analyse image time series in a fast and accurate manner and to detect abnormal change in near real time. An increasing number of change detection techniques have become available that are able to process historical satellite image time series data to detect changes in the past. However, methods that detect changes near real-time, i.e. analysing newly acquired data with respect to the historical series, are lacking. We propose a statistical technique for monitoring change in near-real time by comparing current data with a seasonal-trend model fitted onto the historical time series. As such, identification of consistent and abnormal change in near-real time becomes possible as soon as new image data is captured. The method is based on the "Break For Additive Seasonal Trend" (BFAST) concept (http://bfast.r-forge.r-project.org/). Disturbances are detected by analysing 16-daily MODIS combined vegetation and temperature indices. Validation is carried out by comparing the detected disturbances with available disturbance data sets (e.g. deforestation in Brazil and MODIS fire products). Preliminary results demonstrated that abrupt changes at the end of time series can be successfully detected while the method remains robust for strong seasonality and atmospheric noise. Cloud masking, however, was identified as a critical issue since periods of persistent cloudiness can be detected as abnormal change. The proposed method is an automatic and robust change detection approach that can be applied on different types of data (e.g. future sensors like the Sentinel constellation that provide higher spatial resolution at regular time steps). The methods for near real-time changes detection are publicly available within the BFAST package for R (http://bfast.r-forge.r-project.org/). Keywords: forest change monitoring, time series imagery, near real-time, change detection

Verbesselt, J.; Kalomenopoulos, M.; de Jong, R.; Zeileis, A.; Herold, M.

2012-12-01

289

Bioluminescence microscopy: application to ATP measurements in single living cells  

Science.gov (United States)

Bioluminescence microscopy can be used to measure intracellular cofactors and ionic concentrations (Ca2+, K+, ATP, NADH), as an alternative to micro- spectrophotometry and micro-fluorimetry, due to the development of sensitive detectors (cooled photomultipliers tubes and CCD). The main limitation comes from the very small and brief intensity of the emitted light. Our instrumentation based on an inverted microscope, equipped with high aperture immersion lenses is presented. Light intensity measurements are carried out through a photomultiplier sorted for low dark current and cooled at -5 degree(s)C to reduce thermal noise. Our first aim is to quantify ATP on single living cells using the firefly luciferin-luciferase couple. Experimental and kinetic aspects are presented to emphasize the potentialities of the technique.

Brau, Frederic; Helle, Pierre; Bernengo, Jean C.

1997-12-01

290

STEGANALYSIS OF REAL TIME IMAGE BY STATISTICAL ATTACKS  

Directory of Open Access Journals (Sweden)

Full Text Available Steganalysis is a technique for the detection of the secret informations embedded in the another image known as cover image and if possible the secret text is tried to recover .In this paper ,two techniques are used for the detection of the hidden data .Firstly, detection done by comparing the histogram of the stego & cover image in which the attacker knows about the cover image without the knowledge of the coding algorithm of the stego image & secondly in the image smoothening technique , the probability distribution function is used for the detection .Based on the difference in statistical parameter of the stego image with cover image detection is done.

SWAGOTA BERA,

2010-09-01

291

POLYPHYLY OF NON-BIOLUMINESCENT VIBRIO FISCHERI SHARING A LUX-LOCUS DELETION  

OpenAIRE

This study reports the first description and molecular characterization of naturally occurring, non-bioluminescent strains of V. fischeri. These ‘dark’ V. fischeri strains remained non-bioluminescent even after treatment with both autoinducer and aldehyde, substrate additions that typically maximize light-production in dim strains of luminous bacteria. Surprisingly, the entire lux locus (8 genes) was absent in over 97% of these dark V. fischeri strains. Although these strains were all col...

Wollenberg, M. S.; Preheim, S. P.; Polz, M. F.; Ruby, E. G.

2011-01-01

292

A Novel lux Operon in the Cryptically Bioluminescent Fish Pathogen Vibrio salmonicida Is Associated with Virulence?  

OpenAIRE

The cold-water-fish pathogen Vibrio salmonicida expresses a functional bacterial luciferase but produces insufficient levels of its aliphatic-aldehyde substrate to be detectably luminous in culture. Our goals were to (i) better explain this cryptic bioluminescence phenotype through molecular characterization of the lux operon and (ii) test whether the bioluminescence gene cluster is associated with virulence. Cloning and sequencing of the V. salmonicida lux operon revealed that homologs of al...

Nelson, Eric J.; Tunsjø, Hege S.; Fidopiastis, Pat M.; Sørum, Henning; Ruby, Edward G.

2007-01-01

293

An improved single-step lysis protocol to measure luciferase bioluminescence in Plasmodium falciparum  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract This report describes the optimization and evaluation of a simple single-step lysis protocol to measure luciferase bioluminescence from genetically modified Plasmodium falciparum. This protocol utilizes a modified commercial buffer to improve speed of assay and consistency in the bioluminescence signal measured by reducing the manipulation steps required to release the cytoplasmic fraction. The utility of this improved assay protocol is demonstrated in typical assays that explore absolute and temporal gene expression activity.

Hasenkamp Sandra

2012-02-01

294

Rapid Sublethal Toxicity Assessment Using Bioluminescent Caenorhabditis elegans, a Novel Whole-Animal Metabolic Biosensor  

OpenAIRE

Sublethal metabolic effects are informative toxicological end points. We used a rapid quantitative metabolic end point, bioluminescence of firefly luciferase expressing Caenorhabditis elegans, to assess effects of sublethal chronic exposure (19 h) to the oxidative stress agent and environmental pollutant cadmium (provided as chloride salt). Bioluminescence declined in a concentration-dependent manner in the concentration range tested (0–30?M Cd), with comparable sensitivity to reproduction...

Lagido, Cristina; Mclaggan, Debbie; Flett, Aileen; Pettitt, Jonathan; Glover, L. Anne

2009-01-01

295

Specific and Quantitative Assessment of Naphthalene and Salicylate Bioavailability by Using a Bioluminescent Catabolic Reporter Bacterium  

OpenAIRE

A bioassay was developed and standardized for the rapid, specific, and quantitative assessment of naphthalene and salicylate bioavailability by use of bioluminescence monitoring of catabolic gene expression. The bioluminescent reporter strain Pseudomonas fluorescens HK44, which carries a transcriptional nahG-luxCDABE fusion for naphthalene and salicylate catabolism, was used. The physiological state of the reporter cultures as well as the intrinsic regulatory properties of the naphthalene deg...

Heitzer, Armin; Webb, Oren F.; Thonnard, Janeen E.; Sayler, Gary S.

1992-01-01

296

Digital image processing for real-time neutron radiography and its applications  

International Nuclear Information System (INIS)

The present paper describes several digital image processing approaches for the real-time neutron radiography (neutron television-NTV), such as image integration, adaptive smoothing and image enhancement, which have beneficial effects on image improvements, and also describes how to use these techniques for applications. Details invisible in direct images of NTV are able to be revealed by digital image processing, such as reversed image, gray level correction, gray scale transformation, contoured image, subtraction technique, pseudo color display and so on. For real-time application a contouring operation and an averaging approach can also be utilized effectively. (author)

297

Limited-memory-BFGS-based iterative algorithm for multispectral bioluminescence tomography with Huber regularization  

Science.gov (United States)

Multispectral bioluminescence tomography is becoming a promising tool because it can resolve the biodistibution of bioluminescent reporters associated with cellular and subcellular function through several millimeters with to centimeters of tissues in vivo. Generally, to recover the bioluminescent sources, the source reconstruction problem is formulated as a nonlinear least-squares-type bounds constrained optimization problem. However, bioluminescence tomography (BLT) is an ill-posed problem. For the sake of stability and uniqueness of BLT, many algorithms have been proposed to regularize the problem, such as L2 norm and L1 norm. Here, we proposed a new regularization method with Huber function to regularize BLT problem to obtain robustness like L1 and rapid convergence of L2. Furthermore, the computational burden is largely increased with the use of spectral data. Therefore, there is a critical need to develop a fast reconstruction algorithm for solving multispectral bioluminescence tomography. In the paper, a limited memory quasi-Newton algorithm for solving the large-scale optimization problem is proposed to fast localize the bioluminescent source. In the numerical simulation, a heterogeneous phantom was used to evaluate the performance of the proposed algorithm with the Monte Carlo based synthetic data. Additionally, the real mouse experiments were conducted to further evaluate the proposed algorithm. The results demonstrate the potential and merits of the proposed algorithm.

Feng, Jinchao; Jia, Kebin; Tian, Jie; Qin, Chenghu; Zhu, Shouping

2010-03-01

298

A model system for pathogen detection using a two-component bacteriophage/bioluminescent signal amplification assay  

Science.gov (United States)

Microbial contamination has become a mounting concern the last decade due to an increased emphasis of minimally processed food products specifically produce, and the recognition of foodborne pathogens such as Campylobacter jejuni, Escherichia coli O157:H7, and Listeria monocytogenes. This research investigates a detection approach utilizing bacteriophage pathogen specificity coupled with a bacterial bioluminescent bioreporter utilizing the quorum sensing molecule from Vibrio fischeri, N-(3-oxohexanoyl)-homoserine lactone (3-oxo-C6-HSL). The 3-oxo-C6-HSL molecules diffuse out of the target cell after infection and induce bioluminescence from a population of 3-oxo-C6-HSL bioreporters (ROLux). E. coli phage M13, a well-characterized bacteriophage, offers a model system testing the use of bacteriophage for pathogen detection through cell-to-cell communication via a LuxR/3-oxo-C6-HSL system. Simulated temperate phage assays tested functionality of the ROLux reporter and production of 3-oxo-C6-HSL by various test strains. These assays showed detection limits of 102cfu after 24 hours in a varietry of detection formats. Assays incorporating the bacteriophage M13-luxI with the ROLux reporter and a known population of target cells were subsequently developed and have shown consistent detection limits of 105cfu target organisms. Measurable light response from high concentrations of target cells was almost immediate, suggesting an enrichment step to further improve detection limits and reduce assay time.

Bright, Nathan G.; Carroll, Richard J.; Applegate, Bruce M.

2004-03-01

299

Description of the larva of Alampoides alychnus (Kirsch, 1873), the first known species with bioluminescent immatures in Euplinthini (Elateridae, Agrypninae)  

Scientific Electronic Library Online (English)

Full Text Available A larva de Alampoides alychnus (Kirsch) é descrita e comparada às larvas bioluminescentes de espécies de Pyrophorini. Larvas foram coletadas vivas no solo, entre uma plantação de cana-de-açúcar e mata ciliar localizada em Campo Novo dos Parecis, Mato Grosso, Brasil. Foram mantidas em laboratório. Um [...] a larva atingiu o estágio pupal e após 14 dias o estágio adulto. Estas larvas diferem das larvas de Pyrophorini principalmente pelo padrão de bioluminescência: um par de órgãos luminescentes no mesonoto e uma série de órgãos luminescentes medianos no metanoto e no abdômen. A morfologia da larva e o padrão bioluminescente da larva e da pupa são descritos pela primeira vez para o gênero e para a tribo. O adulto não apresentou luminescência ou vestígio de órgão luminescente. Abstract in english Mature larva of Alampoides alychnus (Kirsch) is described and compared to known Pyrophorini immatures. Larvae were collected live in the soil of a region dominated by sugarcane plantation and gallery forest in Campo Novo dos Parecis, Mato Grosso, Brazil. They were maintained in laboratory and the pu [...] pal period lasted 14 days. This larva differs from other Pyrophorini larvae mainly by bioluminescent pattern: one pair of luminous spots on the mesonotum, and a longitudinal series of median spots on the metanotum and all abdominal segments. The morphology of larva and the bioluminescent pattern of larva and pupa are described for the first time to the genus and the tribe. The fact that adults show no trace of luminescence is emphasized.

Simone Policena, Rosa; Cleide, Costa.

300

A Remote Laboratory for Real-Time Digital Image Processing on Embedded Systems  

OpenAIRE

The purpose of this paper is to present a Remote Laboratory on embedded systems focused in real-time digital image processing. This laboratory consists of a Main Web Server and several Workstations which are designed for digital image retrieval from a CMOS Image Sensor and real-time image processing on a Digital Signal Processor development platform. The Main Web Server redirects the authorised remote users to available Workstations in order to execute and verify their image processing algori...

Evangelos Zigouris; Dimitrios Markonis; Athanasios Kalantzopoulos

2009-01-01

301

FNR-mediated regulation of bioluminescence and anaerobic respiration in the light-organ symbiont Vibrio fischeri  

OpenAIRE

Vibrio fischeri induces both anaerobic respiration and bioluminescence during symbiotic infection. In many bacteria, the oxygen-sensitive regulator FNR activates anaerobic respiration, and a preliminary study using the light-generating lux genes from V. fischeri MJ1 cloned in Escherichia coli suggested that FNR stimulates bioluminescence. To test for FNR-mediated regulation of bioluminescence and anaerobic respiration in V. fischeri, we generated fnr mutants of V. fischeri strains MJ1 and ES1...

Septer, Alecia N.; Bose, Jeffrey L.; Dunn, Anne K.; Stabb, Eric V.

2010-01-01

302

Impact of Site-Directed Mutant Luciferase on Quantitative Green and Orange/Red Emission Intensities in Firefly Bioluminescence  

OpenAIRE

Firefly bioluminescence has attracted great interest because of its high quantum yield and intriguing modifiable colours. Modifications to the structure of the enzyme luciferase can change the emission colour of firefly bioluminescence, and the mechanism of the colour change has been intensively studied by biochemists, structural biologists, optical physicists, and quantum-chemistry theorists. Here, we report on the quantitative spectra of firefly bioluminescence catalysed by wild-type and fo...

Yu Wang,; Hidefumi Akiyama; Kanako Terakado; Toru Nakatsu

2013-01-01

303

Automated Hierarchical Time Gain Compensation for In Vivo Ultrasound Imaging  

DEFF Research Database (Denmark)

Time gain compensation (TGC) is essential to ensure the optimal image quality of the clinical ultrasound scans. When large fluid collections are present within the scan plane, the attenuation distribution is changed drastically and TGC compensation becomes challenging. This paper presents an automated hierarchical TGC (AHTGC) algorithm that accurately adapts to the large attenuation variation between different types of tissues and structures. The algorithm relies on estimates of tissue attenuation, scattering strength, and noise level to gain a more quantitative understanding of the underlying tissue and the ultrasound signal strength. The proposed algorithm was applied to a set of 44 in vivo abdominal movie sequences each containing 15 frames. Matching pairs of in vivo sequences, unprocessed and processed with the proposed AHTGC were visualized side by side and evaluated by two radiologists in terms of image quality. Wilcoxon signed-rank test was used to evaluate whether radiologists preferred the processed sequences or the unprocessed data. The results indicate that the average visual analogue scale (VAS) is positive ( p-value: 2.34 × 10?13) and estimated to be 1.01 (95% CI: 0.85; 1.16) favoring the processed data with the proposed AHTGC algorithm.

Moshavegh, Ramin; Hemmsen, Martin Christian

2015-01-01

304

Monitoring of historical frescoes by timed infrared imaging analysis  

Science.gov (United States)

The subflorescence and efflorescence phenomena are widely acknowledged as the major causes of permanent damage to fresco wall paintings. They are related to the occurrence of cycles of dry/wet conditions inside the walls. Therefore, it is essential to identify the presence of water on the decorated surfaces and inside the walls. Nondestructive testing in industrial applications have confirmed that active infrared thermography with continuous timed images acquisition can improve the outcomes of thermal analysis aimed to moisture identification. In spite of that, in cultural heritage investigations these techniques have not been yet used extensively on a regular basis. This paper illustrates an application of these principles in order to evaluate the decay of fresco mural paintings in a medieval chapel located in North-West of Italy. One important feature of this study is the use of a robotic system called aIRview that can be utilized to automatically acquire and process thermal images. Multiple accurate thermal views of the inside walls of the building have been produced in a survey that lasted several days. Signal processing algorithms based on Fast Fourier Transform analysis have been applied to the acquired data in order to formulate trustworthy hypotheses about the deterioration mechanisms.

Cadelano, G.; Bison, P.; Bortolin, A.; Ferrarini, G.; Peron, F.; Girotto, M.; Volinia, M.

2015-03-01

305

Adaptive smoothing in real-time image stabilization  

Science.gov (United States)

When using the conventional fixed smoothing factor to display the stabilized video, we have the issue of large undefined black border regions (BBR) when camera is fast panning and zooming. To minimize the size of BBR and also provide smooth visualization to the display, this paper discusses several novel methods that have demonstrated on a real-time platform. These methods include an IIR filter, a single Kalman filter and an interactive multi-model filter. The fundamentals of these methods are to adapt the smoothing factor to the motion change from time to time to ensure small BBR and least jitters. To further remove the residual BBR, the pixels inside the BBR are composited from the previous frames. To do that, we first store the previous images and their corresponding frame-to-frame (F2F) motions in a FIFO queue, and then start filling the black pixels from valid pixels in the nearest neighbor frame based on the F2F motion. If a matching is found, then the search is stopped and continues to the next pixel. If the search is exhausted, the pixel remains black. These algorithms have been implemented and tested in a TI DM6437 processor.

Wu, Shunguang; Zhang, David C.; Zhang, Yuzheng; Basso, James; Melle, Michael

2012-05-01

306

Visible light induced ocular delayed bioluminescence as a possible origin of negative afterimage.  

Science.gov (United States)

The delayed luminescence of biological tissues is an ultraweak reemission of absorbed photons after exposure to external monochromatic or white light illumination. Recently, Wang, Bókkon, Dai and Antal (2011) [10] presented the first experimental proof of the existence of spontaneous ultraweak biophoton emission and visible light induced delayed ultraweak photon emission from in vitro freshly isolated rat's whole eye, lens, vitreous humor and retina. Here, we suggest that the photobiophysical source of negative afterimage can also occur within the eye by delayed bioluminescent photons. In other words, when we stare at a colored (or white) image for few seconds, external photons can induce excited electronic states within different parts of the eye that is followed by a delayed reemission of absorbed photons for several seconds. Finally, these reemitted photons can be absorbed by non-bleached photoreceptors that produce a negative afterimage. Although this suggests the photobiophysical source of negative afterimages is related retinal mechanisms, cortical neurons have also essential contribution in the interpretation and modulation of negative afterimages. PMID:21463953

Bókkon, I; Vimal, R L P; Wang, C; Dai, J; Salari, V; Grass, F; Antal, I

2011-05-01

307

Breast cancer cell targeting by prenylation inhibitors elucidated in living animals with a bioluminescence reporter  

Science.gov (United States)

Purpose Inhibitors of protein prenylation, including prenyltransferase inhibitors and aminobisphosphonates such as zoledronic acid, are being investigated intensively as therapeutics in cancer and other diseases. Determining whether prenylation inhibitors directly or indirectly target tumor and/or host cells is key to understanding therapeutic mechanisms. Experimental Design To determine which cell types can be targeted directly by distinct classes of prenylation inhibitors in vivo, we describe herein the development and implementation of a sensitive and pharmacologically specific bioluminescence-based imaging reporter that is inducible by prenylation inhibitors. Results In mouse xenograft models of breast cancer using reporter-bearing mammary fat pad- or bone-localized tumor cells, we show that a prenyltransferase inhibitor robustly induces reporter activity in vivo. In contrast, zoledronic acid, a bone-associated aminobisphosphonate that exerts adjuvant chemotherapeutic activity in breast cancer patients, fails to induce reporter activity in tumor cells of either model. Conclusions Whereas a prenyltransferase inhibitor can directly target breast cancer cells in vivo, zoledronic acid and related aminobisphosphonates are likely to exert anti-tumor activity indirectly by targeting host cells. Accordingly, these findings shift attention toward the goal of determining which host cell types are targeted directly by aminobisphosphonates to exert adjuvant chemotherapeutic activity. PMID:22693355

Chinault, Sharon L.; Prior, Julie L.; Kaltenbronn, Kevin M.; Penly, Anya; Weilbaecher, Katherine N.; Piwnica-Worms, David; Blumer, Kendall J.

2013-01-01

308

The forward problem algorithm based on modified element free Galerkin method for bioluminescence tomography.  

Science.gov (United States)

As an emerging and promising molecular imaging modality, bioluminescence tomography (BLT) can reconstruct the internal light source with the photon fluence on the small animal surface to reveal non-invasive molecular and cellular activities directly. In order to obtain higher precision and better spatial resolution in source reconstruction, the solution accuracy for the forward problem of BLT should be improved as high as possible. In this contribution, we present a modified element free Galerkin method (MEFGM) to calculate photon propagation in the biological tissue. This method is based on moving least squares (MLS) approximation which requires only a series of nodes in the region of interest, so complicated meshing task can be avoided compared with finite element method (FEM). Furthermore, MLS shape functions are further modified to satisfy the delta function property, which can simplify the processing of boundary conditions in comparison with traditional meshless methods. Finally, the numerical simulation experiments demonstrate the effectiveness and feasibility of this proposed method by comparing the solution of MEFGM with that of FEM. PMID:19163526

Qin, Chenghu; Tian, Jie; Liu, Kai; Dai, Yakang

2008-01-01

309

Real-time dynamic holographic image storage device  

Science.gov (United States)

A real-time dynamic holographic image storage device uses four-wave mixing in a pair of photorefractive crystals. An oscillation is produced between the crystals which can be maintained indefinitely after the initial object beam is discontinued. The object beam produces an interference pattern in a first crystal to produce phase-conjugated object beam which is directed towards the second crystal. In the second crystal another interference pattern is created which produces a reconstructed object beam. The reconstructed object beam is directed back towards the first crystal. The interference patterns are produced by interaction of the object and phase-conjugated object beam with a read and write beam in each of the crystals. By manipulation of the ratio of the read and write beam intensities in at least one of the crystals, the phase-conjugate or reconstructed object beam output therefrom can be amplified to maintain stable oscillation between the two crystals.

Lafleur, Sharon S.; Montgomery, Raymond C.

1990-04-01

310

Microwave Imaging for Breast Cancer Detection : Comparison of Tomographic Imaging Algorithms using Single-Frequency and Time-Domain Data  

DEFF Research Database (Denmark)

Still more research groups are promoting microwave imaging as a viable supplement or substitution to more conventional imaging modalities. A widespread approach for microwave imaging of the breast is tomographic imaging in which one seeks to reconstruct the distributions of permittivity and conductivity in the breast. In this paper two nonlinear tomographic algorithms are compared – one is a single-frequency algorithm and the other is a time-domain algorithm.

Rubæk, Tonny; Fhager, Andreas

2011-01-01

311

High-throughput viability assay using an autonomously bioluminescent cell line with a bacterial lux reporter.  

Science.gov (United States)

Cell viability assays are extensively used to determine cell health, evaluate growth conditions, and assess compound cytotoxicity. Most existing assays are endpoint assays, in which data are collected at one time point after termination of the experiment. The time point at which toxicity of a compound is evident, however, depends on the mechanism of that compound. An ideal cell viability assay allows the determination of compound toxicity kinetically without having to terminate the assay prematurely. We optimized and validated a reagent-addition-free cell viability assay using an autoluminescent HEK293 cell line that stably expresses bacterial luciferase and all substrates necessary for bioluminescence. This cell viability assay can be used for real-time, long-term measurement of compound cytotoxicity in live cells with a signal-to-basal ratio of 20- to 200-fold and Z-factors of ~0.6 after 24-, 48- 72-, or 96-h incubation with compound. We also found that the potencies of nine cytotoxic compounds correlated well with those measured by four other commonly used cell viability assays. The results demonstrated that this kinetic cell viability assay using the HEK293(lux) autoluminescent cell line is useful for high-throughput evaluation of compound cytotoxicity. PMID:25447977

Class, Bradley; Thorne, Natasha; Aguisanda, Francis; Southall, Noel; McKew, John C; Zheng, Wei

2015-04-01

312

Time-resolved imaging system for fluorescence-guided surgery with lifetime imaging capability  

Science.gov (United States)

We present a single-photon camera for fluorescence imaging, with a time resolution better than 100ps, capable of providing both intensity and lifetime images. the camera was fabricated in standard CMOS technology. With this FluoCam we show the possibility to study sub-nanosecond fluorescence mechanisms. The FluoCam was used to characterize a near-infrared probe, indocyanine green, conjugated with multimeric cyclic pentapeptide (cRGD). The fluorescent probe-conjugated was used to target and mark tumors with better specificity, in particular aiming at targeting the integrins ?v?3 and ?v?5. As a first step towards clinical studies, preliminary results obtained in-vivo are presented. The first envisioned clinical application would be image-guided surgical oncology to help the surgeon to remove tumor tissue by a better discrimination from normal tissues and also to improve the detection of metastatic lymph nodes. A further application could be the in-vivo determination of the ?v?3 and ?v?5 targets to select patients for therapy with RGD chemotherapy conjugates.

Powolny, F.; Homicsko, K.; Sinisi, R.; Bruschini, Claudio E.; Grigoriev, E.; Homulle, H.; Prior, John O.; Hanahan, D.; Dubikovskaya, E.; Charbon, E.

2014-05-01

313

Evaluation of bioluminescence-based assays of anti-malarial drug activity  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Transgenic Plasmodium falciparum expressing luciferase offers an attractive bioluminescence-based assay platform for the investigation of the pharmacological properties of anti-malarial drugs. Here a side-by-side comparison of bioluminescence and fluorescence-based assays, utilizing a luciferase reporter cassette that confers a strong temporal pattern of luciferase expression during the S-phase of intraerythrocytic development, is reported. Methods Key assay parameters for a range of commercially available luminogenic substrates are determined and compared to those measured using a Malaria Sybr Green I fluorescence assay. In addition, the short-term temporal effects of anti-malarial compounds are evaluated using both bioluminescent and fluorescent assay platforms. Results The Z’, % coefficient of variation and 50% inhibition concentrations are essentially the same for bioluminescent and fluorescent assays in transgenic parasites generated in both chloroquine-sensitive and -resistant genetic backgrounds. Bioluminescent assays, irrespective of the luminogenic agent employed, do, however, offer significantly enhanced signal-to-noise ratios. Moreover, the bioluminescent assay is more dynamic in terms of determining temporal effects immediately following drug perturbation. Conclusion This study suggests that opportunities for bioluminescence-based assays lie not in the measurement of 50% inhibition concentrations, where the cheaper fluorescence assay performs excellently and is not restricted by the need to genetically modify the parasite clone under investigation. Instead, assays that use the dynamic response of the luciferase reporter for semi-automated screening of additional pharmacological properties, such as relative rate-of-kill and lethal dose estimation, are a more attractive development opportunity.

Hasenkamp Sandra

2013-02-01

314

Collinear, two-color optical Kerr effect shutter for ultrafast time-resolved imaging  

CERN Document Server

Imaging with ultrashort exposure times is generally achieved with a crossed-beam geometry. In the usual arrangement, an off-axis gating pulse induces birefringence in a medium exhibiting a strong Kerr response (commonly carbon disulfide) which is followed by a polarizer aligned to fully attenuate the on-axis imaging beam. By properly timing the gate pulse, imaging light experiences a polarization change allowing time-dependent transmission through the polarizer to form an ultrashort image. The crossed-beam system is effective in generating short gate times, however, signal transmission through the system is complicated by the crossing angle of the gate and imaging beams. This work presents a robust ultrafast time-gated imaging scheme based on a combination of type-I frequency doubling and a collinear optical arrangement in carbon disulfide. We discuss spatial effects arising from crossed-beam Kerr gating, and examine the imaging spatial resolution and transmission timing affected by collinear activation of th...

Purwar, Harsh; Rozé, Claude; Sedarsky, David; Blaisot, Jean-Bernard

2015-01-01

315

Time-resolved computed tomography of the liver: retrospective, multi-phase image reconstruction derived from volumetric perfusion imaging  

International Nuclear Information System (INIS)

To assess feasibility and image quality (IQ) of a new post-processing algorithm for retrospective extraction of an optimised multi-phase CT (time-resolved CT) of the liver from volumetric perfusion imaging. Sixteen patients underwent clinically indicated perfusion CT using 4D spiral mode of dual-source 128-slice CT. Three image sets were reconstructed: motion-corrected and noise-reduced (MCNR) images derived from 4D raw data; maximum and average intensity projections (time MIP/AVG) of the arterial/portal/portal-venous phases and all phases (total MIP/ AVG) derived from retrospective fusion of dedicated MCNR split series. Two readers assessed the IQ, detection rate and evaluation time; one reader assessed image noise and lesion-to-liver contrast. Time-resolved CT was feasible in all patients. Each post-processing step yielded a significant reduction of image noise and evaluation time, maintaining lesion-to-liver contrast. Time MIPs/AVGs showed the highest overall IQ without relevant motion artefacts and best depiction of arterial and portal/portal-venous phases respectively. Time MIPs demonstrated a significantly higher detection rate for arterialised liver lesions than total MIPs/AVGs and the raw data series. Time-resolved CT allows data from volumetric perfusion imaging to be condensed into an optimised multi-phase liver CT, yielding a superior IQ and higher detection rate for arterialised liver lesions than the raw data series. (orig.)

316

Real-time computer-generated integral imaging and 3D image calibration for augmented reality surgical navigation.  

Science.gov (United States)

Autostereoscopic 3D image overlay for augmented reality (AR) based surgical navigation has been studied and reported many times. For the purpose of surgical overlay, the 3D image is expected to have the same geometric shape as the original organ, and can be transformed to a specified location for image overlay. However, how to generate a 3D image with high geometric fidelity and quantitative evaluation of 3D image's geometric accuracy have not been addressed. This paper proposes a graphics processing unit (GPU) based computer-generated integral imaging pipeline for real-time autostereoscopic 3D display, and an automatic closed-loop 3D image calibration paradigm for displaying undistorted 3D images. Based on the proposed methods, a novel AR device for 3D image surgical overlay is presented, which mainly consists of a 3D display, an AR window, a stereo camera for 3D measurement, and a workstation for information processing. The evaluation on the 3D image rendering performance with 2560×1600 elemental image resolution shows the rendering speeds of 50-60 frames per second (fps) for surface models, and 5-8 fps for large medical volumes. The evaluation of the undistorted 3D image after the calibration yields sub-millimeter geometric accuracy. A phantom experiment simulating oral and maxillofacial surgery was also performed to evaluate the proposed AR overlay device in terms of the image registration accuracy, 3D image overlay accuracy, and the visual effects of the overlay. The experimental results show satisfactory image registration and image overlay accuracy, and confirm the system usability. PMID:25465067

Wang, Junchen; Suenaga, Hideyuki; Liao, Hongen; Hoshi, Kazuto; Yang, Liangjing; Kobayashi, Etsuko; Sakuma, Ichiro

2015-03-01

317

Exploiting Molecular Biology by Time-Resolved Fluorescence Imaging  

Science.gov (United States)

Many contemporary biological investigations rely on highly sensitive in vitro assays for the analysis of specific molecules in biological specimens, and the main part of these assays depends on high-sensitivity fluorescence detection techniques for the final readout. The analyzed molecules and molecular interactions in the specimen need to be detected in the presence of other highly abundant biomolecules, while the analyzed molecules themselves are only present at nano-, pico-, or even femtomolar concentration.A short scientific rationale of fluorescence is presented. It emphasizes the use of fluorescent labels for sensitive assays in life sciences and specifies the main properties of an ideal fluorophore. With fluorescence lifetimes in the microsecond range and fluorescence quantum yield of 0.4 some water soluble complexes of Ruthenium like modified Ru(sulfobathophenanthroline) complexes fulfill these properties. They are outstanding fluorescent labels for ultrasensitive assays as illustrated in two examples, in drug discovery and in point of care testing.We discuss the fundamentals and the state-of-the-art of the most sensitive time-gated fluorescence assays. We reflect on how the imaging devices currently employed for readout of these assays might evolve in the future. Many contemporary biological investigations rely on highly sensitive in vitro assays for the analysis of specific molecules in biological specimens, and the main part of these assays depends on high-sensitivity fluorescence detection techniques for the final readout. The analyzed molecules and molecular interactions in the specimen need to be detected in the presence of other highly abundant biomolecules, while the analyzed molecules themselves are only present at nano-, pico-, or even femtomolar concentration.A short scientific rationale of fluorescence is presented. It emphasizes the use of fluorescent labels for sensitive assays in life sciences and specifies the main properties of an ideal fluorophore. With fluorescence lifetimes in the microsecond range and fluorescence quantum yield of 0.4 some water soluble complexes of Ruthenium like modified Ru(sulfobathophenanthroline) complexes fulfil these properties. They are outstanding fluorescent labels for ultrasensitive assays as illustrated in two examples, in drug discovery and in point of care testing.We discuss the fundamentals and the state-of-the-art of the most sensitive time-gated fluorescence assays. We reflect on how the imaging devices currently employed for readout of these assays might evolve in the future.

Müller, Francis; Fattinger, Christof

318

Bioluminescence-based detection of microRNA, miR21 in breast cancer cells.  

Science.gov (United States)

A hybridization assay for the detection of microRNA, miR21 in cancer cells using the bioluminescent enzyme Renilla luciferase (Rluc) as a label, has been developed. MicroRNAs are small RNAs found in plants, animals, and humans that perform key functions in gene silencing and affect early-stage cell development, cell differentiation, and cell death. miRNAs are considered useful early diagnostic and prognostic markers of cancer, candidates for therapeutic intervention, and targets for basic biomedical research. However, methods for highly sensitive and rapid detection of miRNA directly from samples such as cells that can serve as a suitable diagnostics platform are lacking. In that regard, the utilization of the bioluminescent label, Rluc, that offers the advantage of high signal-to-noise ratio, allows for the development of highly sensitive assays for the determination of miRNA in a variety of matrixes. In this paper, we have described the development of a competitive oligonucleotide hybridization assay for the detection of miR21 using the free miR21 and Rluc-labeled miR21 that competes to bind to an immobilized miR21 complementary probe. The miR21 microRNA chosen for this study is of biomedical significance because its levels are elevated in a variety of cancers. Using the optimized assay, a detection limit of 1 fmol was obtained. The assay was employed for the detection of miR21 in human breast adenocarcinoma MCF-7 cells and nontumorigenic epithelial MCF-10A cells. The comparison of miR21 expression level in two cell lines demonstrated higher expression of miR21 in breast cancer cell line MCF-7 compared to the nontumorigenic MCF-10A cells. Further, using the assay developed, the miR21 quantification could be performed directly in cell extracts. The hybridization assay was developed in a microplate format with a total assay time of 1.5 h and without the need for sample PCR amplification. The need for early molecular markers and their detection methods in cancer diagnosis is tremendous. The characteristics of the assay developed in this work show its suitability for early cancer diagnosis based on miRNA as a biomarker. PMID:18302417

Cissell, Kyle A; Rahimi, Yasmeen; Shrestha, Suresh; Hunt, Eric A; Deo, Sapna K

2008-04-01

319

Evaluation of a bioluminescent mouse model expressing aromatase PII-promoter-controlled luciferase as a tool for the study of endocrine disrupting chemicals  

International Nuclear Information System (INIS)

Dysfunction of the enzyme aromatase (CYP19) is associated with endocrine pathologies such as osteoporosis, impaired fertility and development of hormone-dependent cancers. Certain endocrine disrupting chemicals affect aromatase expression and activity in vitro, but little is known about their ability to do so in vivo. We evaluated a bioluminescent mouse model (LPTA (registered) )CD-1-Tg(Cyp19-luc)-Xen) expressing luciferase under control of the gonadal aromatase pII promoter as an in vivo screening tool for chemicals that may affect aromatase expression. We studied the effects of forskolin, pregnant mare serum gonadotropin and atrazine in this model (atrazine was previously shown to induced pII-promoter-driven aromatase expression in H295R human adrenocortical carcinoma cells). About 2-4 out of every group of 10 male or female Cyp19-luc mice injected i.p. with 10 mg/kg forskolin had increased gonadal bioluminescence after 3-5 days compared to controls; the others appeared non-responsive. Similarly, about 4 per group of 9 individual females injected with pregnant mare serum gonadotropin had increased ovarian bioluminescence after 24 h. There was a statistically significant correlation between ovarian bioluminescence and plasma estradiol concentrations (n = 14; p = 0.022). Males exposed to a single dose of 100 mg/kg or males and females exposed to 5 daily injections of 30 mg/kg atrazine showed no change in gonadal bioluminescence over a 7 day period, but a significant ie over a 7 day period, but a significant interaction was found between atrazine (100 mg/kg) and time in female mice (p < 0.05; two-way ANOVA). Ex vivo luciferase activity in dissected organs was increased by forskolin in testis, epididymis and ovaries. Atrazine (30 mg/kg/day) increased (30%) luciferase activity significantly in epididymis only. In conclusion, certain individual Cyp19-luc mice are highly responsive to aromatase inducers, suggesting this model, with further optimization, may have potential as an in vivo screening tool for environmental contaminants.

320

High throughput web inspection system using time-stretch real-time imaging  

Science.gov (United States)

Photonic time-stretch is a novel technology that enables capturing of fast, rare and non-repetitive events. Therefore, it operates in real-time with ability to record over long period of time while having fine temporal resolution. The powerful property of photonic time-stretch has already been employed in various fields of application such as analog-to-digital conversion, spectroscopy, laser scanner and microscopy. Further expanding the scope, we fully exploit the time-stretch technology to demonstrate a high throughput web inspection system. Web inspection, namely surface inspection is a nondestructive evaluation method which is crucial for semiconductor wafer and thin film production. We successfully report a dark-field web inspection system with line scan speed of 90.9 MHz which is up to 1000 times faster than conventional inspection instruments. The manufacturing of high quality semiconductor wafer and thin film may directly benefit from this technology as it can easily locate defects with area of less than 10 microm x 10 microm where it allows maximum web flow speed of 1.8 km/s. The thesis provides an overview of our web inspection technique, followed by description of the photonic time-stretch technique which is the keystone in our system. A detailed explanation of each component is covered to provide quantitative understanding of the system. Finally, imaging results from a hard-disk sample and flexible films are presented along with performance analysis of the system. This project was the first application of time-stretch to industrial inspection, and was conducted under financial support and with close involvement by Hitachi, Ltd.

Kim, Chanju

321

When should we recommend use of dual time-point and delayed time-point imaging techniques in FDG PET?  

Science.gov (United States)

FDG PET and PET/CT are now widely used in oncological imaging for tumor characterization, staging, restaging, and response evaluation. However, numerous benign etiologies may cause increased FDG uptake indistinguishable from that of malignancy. Multiple studies have shown that dual time-point imaging (DTPI) of FDG PET may be helpful in differentiating malignancy from benign processes. However, exceptions exist, and some studies have demonstrated significant overlap of FDG uptake patterns between benign and malignant lesions on delayed time-point images. In this review, we summarize our experience and opinions on the value of DTPI and delayed time-point imaging in oncology, with a review of the relevant literature. We believe that the major value of DTPI and delayed time-point imaging is the increased sensitivity due to continued clearance of background activity and continued FDG accumulation in malignant lesions, if the same diagnostic criteria (as in the initial standard single time-point imaging) are used. The specificity of DTPI and delayed time-point imaging depends on multiple factors, including the prevalence of malignancies, the patient population, and the cut-off values (either SUV or retention index) used to define a malignancy. Thus, DTPI and delayed time-point imaging would be more useful if performed for evaluation of lesions in regions with significant background activity clearance over time (such as the liver, the spleen, the mediastinum), and if used in the evaluation of the extent of tumor involvement rather than in the characterization of the nature of any specific lesion. Acute infectious and non-infectious inflammatory lesions remain as the major culprit for diminished diagnostic performance of these approaches (especially in tuberculosis-endemic regions). Tumor heterogeneity may also contribute to inconsistent performance of DTPI. The authors believe that selective use of DTPI and delayed time-point imaging will improve diagnostic accuracy and interpretation confidence in FDG PET imaging. PMID:23361859

Cheng, Gang; Torigian, Drew A; Zhuang, Hongming; Alavi, Abass

2013-05-01

322

When should we recommend use of dual time-point and delayed time-point imaging techniques in FDG PET?  

Energy Technology Data Exchange (ETDEWEB)

FDG PET and PET/CT are now widely used in oncological imaging for tumor characterization, staging, restaging, and response evaluation. However, numerous benign etiologies may cause increased FDG uptake indistinguishable from that of malignancy. Multiple studies have shown that dual time-point imaging (DTPI) of FDG PET may be helpful in differentiating malignancy from benign processes. However, exceptions exist, and some studies have demonstrated significant overlap of FDG uptake patterns between benign and malignant lesions on delayed time-point images. In this review, we summarize our experience and opinions on the value of DTPI and delayed time-point imaging in oncology, with a review of the relevant literature. We believe that the major value of DTPI and delayed time-point imaging is the increased sensitivity due to continued clearance of background activity and continued FDG accumulation in malignant lesions, if the same diagnostic criteria (as in the initial standard single time-point imaging) are used. The specificity of DTPI and delayed time-point imaging depends on multiple factors, including the prevalence of malignancies, the patient population, and the cut-off values (either SUV or retention index) used to define a malignancy. Thus, DTPI and delayed time-point imaging would be more useful if performed for evaluation of lesions in regions with significant background activity clearance over time (such as the liver, the spleen, the mediastinum), and if used in the evaluation of the extent of tumor involvement rather than in the characterization of the nature of any specific lesion. Acute infectious and non-infectious inflammatory lesions remain as the major culprit for diminished diagnostic performance of these approaches (especially in tuberculosis-endemic regions). Tumor heterogeneity may also contribute to inconsistent performance of DTPI. The authors believe that selective use of DTPI and delayed time-point imaging will improve diagnostic accuracy and interpretation confidence in FDG PET imaging. (orig.)

Cheng, Gang [Philadelphia VA Medical Center, Department of Radiology, Philadelphia, PA (United States); Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Torigian, Drew A.; Alavi, Abass [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Zhuang, Hongming [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

2013-05-15

323

GPU-Based Real-Time Volumetric Ultrasound Image Reconstruction for a Ring Array  

OpenAIRE

Synthetic phased array (SPA) beamforming with Hadamard coding and aperture weighting is an optimal option for real-time volumetric imaging with a ring array, a particularly attractive geometry in intracardiac and intravascular applications. However, the imaging frame rate of this method is limited by the immense computational load required in synthetic beamforming. For fast imaging with a ring array, we developed graphics processing unit (GPU)-based, real-time image reconstruction software th...

Choe, Jung Woo; Nikoozadeh, Amin; Oralkan, O?mer; Khuri-yakub, Butrus T.

2013-01-01

324

High time-resolution sprite imaging: observations and implications  

Energy Technology Data Exchange (ETDEWEB)

Sprites are large scale manifestations of electrical streamers triggered in the upper atmosphere by lightning in an underlying thunderstorm. Imaging of sprites at 10 000 frames per second has provided new insights into their spatial and temporal development. In this paper we discuss the experimental protocols that have been developed for performing high-speed observations of sprites and some new observations that have been obtained of relevance to laboratory experiments. Downward tendrils and upward branches, so characteristic in video recordings, are shown to be formed by very fast streamer heads with velocities up to half the speed of light. The streamer heads are spatially small, {approx}100 m or less, but very bright with emission rates up to {approx}10{sup 24} photons s{sup -1}. The sprite onset begins with a downward streamer. Then, in some sprites, at a little later time and from a lower altitude upward moving streamer heads may also appear. If there are no upward streamers the sprite would be classified as a 'C-sprite'; with both downward and upward streamers it would be a 'carrot sprite'. The optical emissions are primarily from the neutral molecular nitrogen first positive bands emitting in the near-infrared, but there are also blue emissions assumed to be from second positive bands of molecular nitrogen and from first negative bands of nitrogen ions. The streamer heads are observed at times to split into several streamer heads. This process appears to be more frequent in the core of larger sprites.

Stenbaek-Nielsen, H C [Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, Ak 99775-7320 (United States); McHarg, M G [Department of Physics, 2354 Fairchild Drive, Suite 2A31, US Air Force Academy, CO 80840 (United States)], E-mail: hnielsen@gi.alaska.edu, E-mail: matthew.mcharg@usafa.edu

2008-12-07

325

Interpreting response time effects in functional imaging studies.  

Science.gov (United States)

It has been suggested that differential neural activity in imaging studies is most informative if it is independent of response time (RT) differences. However, others view RT as a behavioural index of key cognitive processes, which is likely linked to underlying neural activity. Here, we reconcile these views using the effort and engagement framework developed by Taylor, Rastle, and Davis (2013) and data from the domain of reading aloud. We propose that differences in neural engagement should be independent of RT, whereas, differences in neural effort should co-vary with RT. We illustrate these different mechanisms using data from an fMRI study of neural activity during reading aloud of regular words, irregular words, and pseudowords. In line with our proposals, activation revealed by contrasts designed to tap differences in neural engagement (e.g., words are meaningful and therefore engage semantic representations more than pseudowords) survived correction for RT, whereas activation for contrasts designed to tap differences in neural effort (e.g., it is more difficult to generate the pronunciation of pseudowords than words) correlated with RT. However, even for contrasts designed to tap neural effort, activity remained after factoring out the RT-BOLD response correlation. This may reveal unpredicted differences in neural engagement (e.g., learning phonological forms for pseudowords>words) that could further the development of cognitive models of reading aloud. Our framework provides a theoretically well-grounded and easily implemented method for analysing and interpreting RT effects in neuroimaging studies of cognitive processes. PMID:24904992

Taylor, J S H; Rastle, Kathleen; Davis, Matthew H

2014-10-01

326

Imaging the small animal cardiovascular system in real-time with multispectral optoacoustic tomography  

Science.gov (United States)

Multispectral Optoacoustic Tomography (MSOT) is an emerging technique for high resolution macroscopic imaging with optical and molecular contrast. We present cardiovascular imaging results from a multi-element real-time MSOT system recently developed for studies on small animals. Anatomical features relevant to cardiovascular disease, such as the carotid arteries, the aorta and the heart, are imaged in mice. The system's fast acquisition time, in tens of microseconds, allows images free of motion artifacts from heartbeat and respiration. Additionally, we present in-vivo detection of optical imaging agents, gold nanorods, at high spatial and temporal resolution, paving the way for molecular imaging applications.

Taruttis, Adrian; Herzog, Eva; Razansky, Daniel; Ntziachristos, Vasilis

2011-03-01

327

PCR-based detection of bioluminescent microbial populations in Tyrrhenian Sea  

Science.gov (United States)

The present study is focused on the development of a cultivation-independent molecular approach for specific detection of bioluminescent bacteria within microbial communities by direct amplification of luxA gene from environmental DNA. A new set of primers, specifically targeting free-living bioluminescent bacteria, was designed on the base of l uxA sequences available from the public database. Meso- and bathypelagic seawater samples were collected from two stations in Tyrrhenian Sea at the depths of 500 and 2750 m. The same seawater samples also were used to isolate bioluminescent bacteria that were further subjected to luxA and 16S rRNA gene sequencing. PCR products obtained by amplification with designed primers were cloned, and the phylogenetic affiliation of 40 clones was determined. All of them were clustered into three groups, only distantly related to the Photobacterium phosphoreum and Photobacterium kishitanii clades. The half of all clones formed a tight monophyletic clade, while the rest of clones were organized in "compartment"-specific, meso- and bathypelagic ecotypes. No matches with luxA gene sequences of four bioluminescent strains, isolated from the same seawater samples, were observed. These findings indicate that the PCR-based approach developed in present manuscript, allowed us to detect the novel, "yet to be cultivated" lineages of bioluminescent bacteria, which are likely specific for distinct warm bathypelagic realms of Mediterranean Sea.

Gentile, Gabriela; De Luca, Massimo; Denaro, Renata; La Cono, Violetta; Smedile, Francesco; Scarfì, Simona; De Domenico, Emilio; De Domenico, Maria; Yakimov, Michail M.

2009-05-01

328

Developing a system for real-time fusing of infrared and visible-light images  

Science.gov (United States)

A simplified system to fuse the infrared and visible light images in real time is introduced in this paper. A Thermal Image System and a CCD camera are used to obtain the infrared and visible light images respectively. The two different sources images can be correlated completely both in the time and in the space after we solve the problems of synchronizing, dimension matching and visual field matching. Afterward, these images can be used in real time fusion or used the further fusing algorithm.

Su, Xuegang; Gao, Zhiyun

1998-09-01

329

Real Time Deconvolution of In-Vivo Ultrasound Images  

DEFF Research Database (Denmark)

The axial resolution in medical ultrasound is directly linked to the emitted ultrasound frequency, which, due to tissue attenuation, is selected based on the depth of scanning. The resolution is etermined by the transducers impulse response, which limits the attainable resolution to be between one and two wavelengths. This can be improved by deconvolution, which increase the bandwidth and equalizes the phase to increase resolution under the constraint of the electronic noise in the received signal. A fixed interval Kalman filter based deconvolution routine written in C is employed. It uses a state based model for the ultrasound pulse and can include a depth varying pulse and spatially varying signal-to-noise ration. An autoregressive moving average (ARMA) model of orders 8 and 9 is used for the pulse, and the ARMA parameters are determined as a function of depth using a minimum variance algorithm using averaging over several RF lines. In vivo data from a 3 MHz mechanically rotating probe is used and the received signal is sampled at 20 MHz and 12 bits. In-vivo data acquired from a 16th week old fetus is used along with a scan from the liver and right kidney of a 27 years old male. The axial resolution has been determined from the in-vivo liver image using the auto-covariance function. From the envelope of the estimated pulse the axial resolution at Full-Width-Half-Max is 0.581 mm corresponding to 1.13 l at 3 MHz. The algorithm increases the resolution to 0.116 mm or 0.227 l corresponding to a factor of 5.1. The basic pulse can be estimated in roughly 0.176 seconds on a single CPU core on an Intel i5 CPU running at 1.8 GHz. An in-vivo image consisting of 100 lines of 1600 samples can be processed in roughly 0.1 seconds making it possible to perform real-time deconvolution on ultrasound data by using dual or quad core CPUs for frame-rates of 20-40 Hz.

Jensen, JØrgen Arendt

2013-01-01

330

In situ measurement of bioluminescence and fluorescence in an integrated microbioreactor.  

Science.gov (United States)

Reporter strains of bacteria that emit light or a fluorescent marker in response to specific conditions in their environment are having a significant impact in many areas of biology, including toxicity assays for environmental pollutants, chemical detection, and gene expression profiling. We have demonstrated methods for in situ measurements of bioluminescence and fluorescence from bacterial cultures grown in 50 microL instrumented microbioreactors. Results from microbioreactors were compared to results obtained from conventional 500 mL batch bioreactors and shake flasks. Experiments were conducted with reporter strains of Escherichia coli in which luxCDABE or gfp was fused to a promoter that was either expressed constitutively, or that responded to oxygen limitation. With these reporter strains, we have demonstrated the ability to obtain information on growth conditions within the microbioreactor. We have also shown that the large aspect ratio of the microbioreactor provides a unique advantage over measurements in larger bioreactors by reducing the inner filter effect in on-line measurements and eliminating the need for error-prone off-line dilutions. In addition, continuous on-line monitoring of genes in real-time, when expanded to include entire reporter libraries, could potentially provide a true dynamic picture of cellular gene expression from which the kinetics of gene expression can be untangled and elucidated. PMID:16187336

Zanzotto, Andrea; Boccazzi, Paolo; Gorret, Nathalie; Van Dyk, Tina K; Sinskey, Anthony J; Jensen, Klavs F

2006-01-01

331

Mechanosensitivity of a rapid bioluminescence reporter system assessed by atomic force microscopy.  

Science.gov (United States)

Cells are sophisticated integrators of mechanical stimuli that lead to physiological, biochemical, and genetic responses. The bioluminescence of dinoflagellates, alveolate protists that use light emission for predator defense, serves as a rapid noninvasive whole-cell reporter of mechanosensitivity. In this study, we used atomic force microscopy (AFM) to explore the relationship between cell mechanical properties and mechanosensitivity in live cells of the dinoflagellate Pyrocystis lunula. Cell stiffness was 0.56 MPa, consistent with cells possessing a cell wall. Cell response depended on both the magnitude and velocity of the applied force. At the maximum stimulation velocity of 390 ?m s(-1), the threshold response occurred at a force of 7.2 ?N, resulting in a contact time of 6.1 ms and indentation of 2.1 ?m. Cells did not respond to a low stimulation velocity of 20 ?m s(-1), indicating a velocity dependent response that, based on stress relaxation experiments, was explained by the cell viscoelastic properties. This study demonstrates the use of AFM to study mechanosensitivity in a cell system that responds at fast timescales, and provides insights into how viscoelastic properties affect mechanosensitivity. It also provides a comparison with previous studies using hydrodynamic stimulation, showing the discrepancy in cell response between direct compressive forces using AFM and those within flow fields based on average flow properties. PMID:25809248

Tesson, Benoit; Latz, Michael I

2015-03-24

332

Density resolutionary optimization of real time radiotherapy portal imagings  

International Nuclear Information System (INIS)

Objective: Electronic portal imaging devices (EPIDs) are widely used as a replacement of portal films for patient position verification, but the image quality is not always optimal. Because of very low density resolution, the portal imaging is difficult to be used clinically. In this study, several transforming models and the optimization exposure or acquisition conditions were studied for optimization portal imaging, which based on DicomRT platform built by ourselves. Methods: 6 MV X-ray from Varian 21EX linac was used to generate portal images by Portal Vision aSi500 amorphous silicon detector image acquisition system. The density resolution study was based on the number of the lines which could be seen in the image of a special Las Vegas image quality test board. The optimization calculating models were focused on equalization after stretch transforming discrete wavelet transform (DWT) and Butter worth high pass filters. The calculation was performed in Matlab language. Results: The optimal numbers of MU, average frames and reset number were 4 - 5, 3 - 4 and 2 - 3, respectively. The density resolution of optimized imaging via equalization after stretch transforming, DWT and Butter worth high pass filter transforming was markedly improved. The bone structure could be definitely distinguished. The number of lines distinguished in Las Vegas image via equalization after stretch transforming, DWT and Better worth high pass filter transforming was 3, 4 and 5, respectivelr transforming was 3, 4 and 5, respectively. Conclusions: The proposed transforming systems, including DWT edge detection and Butter worth high pass filter transform, are suitable for improving density resolving power of MV X-ray portal image. (authors)

333

Resistivity structures imaging using time-domain electromagnetic data; TDEM ho ni yoru chika hiteiko kozo no imaging  

Energy Technology Data Exchange (ETDEWEB)

The kernel function for transient vertical magnetic dipole was defined for semi-infinite uniform medium, and the 1-D imaging algorithm by TDEM (time-domain electromagnetic) method was developed for underground resistivity structure. Electromagnetic migration method directly images sectional resistivity profiles from the data observed by frequency-domain MT method, and determines underground resistivity profiles by integral equation of MT field using the concept of return travel time in reflection seismic exploration. The method reported in this paper is also one of the EM migration methods. The imaging algorithm of 2-D resistivity structure was developed by correcting 1-D imaging in consideration of the effect of 2-D anomaly on 1-D imaging (the resistivity of anomaly can be obtained from the resistivity contrast between anomaly and medium). The conventional methods require enormous forward computation, while this method can obtain underground resistivity structure in extremely short computation time, resulting in superior practicability. 12 refs., 7 figs.

Noguchi, K. [Waseda University, Tokyo (Japan). School of Science and Engineering; Endo, M. [Waseda University, Tokyo (Japan)

1996-10-01

334

Molecular imaging in oncology  

International Nuclear Information System (INIS)

Molecular imaging is generally defined as noninvasive and quantitative imaging of targeted macromolecules and biological processes in living organisms. A characteristic of molecular imaging is the ability to perform repeated studies and assess changes in biological processes over time. Thus molecular imaging lends itself well for monitoring the effectiveness of tumor therapy. In animal models a variety of techniques can be used for molecular imaging. These include optical imaging (bioluminescence and fluorescence imaging), magnetic resonance imaging (MRI) and nuclear medicine techniques. In the clinical setting, however, nuclear medicine techniques predominate, because so far only radioactive tracers provide the necessary sensitivity to study expression and function of macromolecules non-invasively in patients. Nuclear medicine techniques allows to study a variety of biological processes in patients. These include the expression of various receptors (estrogen, androgen, somatostatin receptors and integrins). In addition, tracers are available to study tumor cell proliferation and hypoxia. The by far most commonly used molecular imaging technique in oncology is, however, positron emission tomography (PET) with the glucose analog [18F]fluorodeoxyglucose (FDG-PET). FDG-PET permits non-invasive quantitative assessment of the accelerated exogenous glucose use of malignant tumors. Numerous studies have now shown that reduction of tumor FDG-uptake during therapy action of tumor FDG-uptake during therapy allows early prediction of tumor response and patient survival. Clinical studies are currently underway to determine whether FDG-PET can be used to individualize tumor therapy by signaling early in the course of therapy the need for therapeutic adjustments in patients with likely non-responding tumors. (orig.)

335

Real-time and Portable Microwave Imaging System  

Science.gov (United States)

Microwave and millimeter wave imaging has shown tremendous utility in a wide variety of applications. These techniques are primarily based on measuring coherent electric field distribution on the target being imaged. Mechanically scanned systems are the simple and low cost solution in microwave imaging. However, these systems are typically bulky and slow. This dissertation presents a design for a 2D switched imaging array that utilizes modulated scattering techniques for spatial multiplexing of the signal. The system was designed to be compact, coherent, possessing high dynamic range, and capable of video frame rate imaging. Various aspects of the system design were optimized to achieve the design objectives. The 2D imaging system as designed and described in this dissertation utilized PIN diode loaded resonant elliptical slot antennas as array elements. The slot antennas allow for incorporating the switching into the antennas thus reducing the cost and size of the array. Furthermore, these slots are integrated in a simple low loss waveguide network. Moreover, the sensitivity and dynamic range of this system is improved by utilizing a custom designed heterodyne receiver and matched filter. This dissertation also presents an analysis on the properties of this system. The performance of the multiplexing scheme, the noise floor and the dynamic range of the receivers are investigated. Furthermore, sources of errors such as mutual coupling and array response dispersion are also investigated. Finally, utilizing this imaging system for various applications such as 2D electric field mapping, scatterer localization, and nondestructive imaging is demonstrated.

Ghasr, Mohammed Tayeb

2009-01-01

336

The roles of the two highly unstable components F and P involved in the bioluminescence of euphausiid shrimps.  

Science.gov (United States)

Bioluminescence of euphausiids takes place when a fluorescent tetrapyrrole F and a highly unstable protein P react in the presence of oxygen. A previous study on the euphausiid Meganyctiphanes norvegica indicated that F acts as a catalyst and P is consumed in the luminescence reaction, differing from the luminescence system of dinoflagellates in which a tetrapyrrole luciferin, nearly identical to F, is enzymatically oxidized in the presence of dinoflagellate luciferase. In the present study, P was extracted from Euphausia pacifica as well as from M. norvegica, then purified separately by affinity chromatography on a column of biliverdin-Sepharose 4B, completing the whole process in less than 5 h. The samples of P obtained from both species had a molecular weight of 600,000, a purity of about 80%, and a specific activity 50-100 times greater than that previously found. The activity of P rapidly decreased in solutions, even at 0 degrees C, and the inactivation of P derived from M. norvegica was more than four times faster than that derived from E. pacifica. The kinetics of the luminescence reaction was investigated with F and P whose concentrations were systematically varied. The reaction was characteristically slow and involved two different reaction rates; the turnover number at 0 degrees C was 30/h for the initial 20 min and 20/h after the initial 1 h. The total light emitted in a 50-h period indicated that the bioluminescence quantum yield of F was about 0.6 at 0 degrees C, and P recycled many times in the luminescence reaction. Thus, the present results conclusively show that F is a luciferin and P is a luciferase of an unusually slow-working type, contrary to early report. PMID:7676855

Shimomura, O

1995-01-01

337

Timing design and image processing of CMOS sensor LUPA-4000 based on FPGA  

Science.gov (United States)

This article describes a method of the timing sequence design for CMOS image sensor LUPA-4000. A FPGA based imaging system with the function of adjustable integration time, multiple-slope integration, parallel integration an reading, windowing readout has been designed. This design can satisfy the frequency of 66M limit frequency of LUPA-4000 and 20 frames of a second. As the fixed noise of LUPA-4000 is aloud and the image is not clear, an efficient real-time image processing algorithm is also described in this paper. First a black image should be acquired as the fixed noise image. The real-time images can be send out after subtracting the noise image. This method can effectively eliminate the fixed noise o f the image, as the same time, the original image information has been maintained in the maximum degree. The test experiments on FPGA shows this design can drive LUPA-4000 working properly. Also this design takes full advantage of the accessibility features of the device, which provides a wider dynamic range and more flexible application of the device. The image sensor driven by this design improves imaging quality, which can be used for space exploration, especially for small space dynamic target tracking.

Xin, Li

2014-11-01

338

Statistical analysis of biophoton image  

Science.gov (United States)

A photon count image system has been developed to obtain the ultra-weak bioluminescence image. The photon images of some plant, animal and human hand have been detected. The biophoton image is different from usual image. In this paper three characteristics of biophoton image are analyzed. On the basis of these characteristics the detected probability and detected limit of photon count image system, detected limit of biophoton image have been discussed. These researches provide scientific basis for experiments design and photon image processing.

Wang, Susheng

1998-08-01

339

Bioluminescência de fungos: distribuição, função e mecanismo de emissão de luz / Fungi bioluminescence: distribution, function and mechanism of light emission  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english The emission of light by living organisms, bioluminescence, has been studied since the nineteenth century. However, some bioluminescent systems, such as fungi, remain poorly understood. The emitter, the two enzymes involved, and the reaction mechanism have not yet been unraveled. Moreover, the ecolo [...] gical role and evolutionary significance for fungal luminescence is also unknown. It is hoped that comprehensive research on fungal bioluminescent systems will generate knowledge and tools for academic and applied sciences. This review discusses the distribution of bioluminescent fungi on Earth, attempts to elucidate the mechanism involved in light emission, and presents preliminary results on the evolution and ecological role of fungal bioluminescence.

Anderson Garbuglio, Oliveira; Rodrigo Pimenta, Carvalho; Hans Eugene, Waldenmaier; Cassius Vinicius, Stevani.

340

An Embedded System of Real-Time Acquisition and Display of Images  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we propose a design of an embedded system which based on CPLD (Complex Programmable Logic Device and only one chip of SRAM (Static RAM in order to acquire and display the images real-time. The system uses Omni Vision’s CMOS color image sensor OV7725 as the image acquisition chip and a 5.6-inch TFT-LCD (Thin Film Transistor Liquid Crystal Display, 18bit (RGB666 colors with resolution of 640 × 480 pixels, to display the images real-time, and the device of CPLD (EPM7160E to control the timing, image format conversion, and TFT-LCD drive signal. At the same time the embedded system use one chip of SRAM as a cache memory to save an image quickly. The experimental results show that the system designed, with high practical value but less hardware, is easy to capture and display the images stably.

Yuwei Peng

2009-06-01

341

VISTA - A Constellation for Real Time Regional Imaging  

Science.gov (United States)

The role of satellites in medium and high-resolution reconnaissance of the Earth's surface has been well demonstrated in recent years through missions such as Landsat, SPOT, IKONOS, ImageSat and Quickbird. The market for such data products is well served and likely to become more competitive with further very-high-resolution missions. Whereas commercial markets have concentrated on enhancing resolution, the small satellite sector has concentrated on reducing the cost of data products, and the development of systems providing niche services. One such EO requirement that can be well met by smaller satellites is the need for higher temporal resolution, as this typically requires a large number of satellites to operate as a constellation - thus far financially impractical using conventional EO satellites. Surrey is currently engaged in building its first constellation that will provide daily global coverage at moderate resolution (32-metre GSD and 600km swath) in three spectral bands. Targeted at providing timely quick-look data products for disaster mitigation and monitoring, the constellation comprises 7 satellites in a single orbital plane. Each satellite has a wide swath so that successive satellites progressively cover the entire globe in a single day. The Vista constellation takes this concept a step further, and is proposed for applications requiring near-continuous surveillance of regional activity. By introducing a multiple plane constellation of small Earth observation satellites, it is possible to monitor continuously selected regions anywhere on the globe. The paper describes the system trades and outlines the scope of the performance that could be obtained from such a system. A cost model illustrates that the balance between launch and space segment costs must be reached by considering suitable replacement strategies, and that the system is highly sensitive to requirement creep. Finally, it is shown that the use of cost effective, small satellites leads to solutions previously thought to be financially beyond sensible reach.

Meerman, Max; Boland, Lee; da Silva Curiel, Alex; Sweeting, Martin, , Sir

2002-01-01

342

Regulated bioluminescence as a tool for bioremediation process monitoring and control of bacterial cultures  

Science.gov (United States)

An effective on-line monitoring technique for toxic waste bioremediation using bioluminescent microorganisms has shown great potential for the description and optimization of biological processes. The lux genes of the bacterium Vibrio fischeri are used by this species to produce visible light. The lux genes can be genetically fused to the control region of a catabolic gene, with the result that bioluminescence is produced whenever the catabolic gene is induced. Thus the detection of light from a sample indicates that genetic expression from a specific gene is occurring. This technique was used to monitor biodegradation of specific contaminants from waste sites. For these studies, fusions between the lux genes and the operons for naphthalene and toluene/xylene degradation were constructed. Strains carrying one of these fusions respond sensitively and specifically to target substrates. Bioluminescence from these cultures can be rapidly measured in a nondestructive and noninvasive manner. The potential for this technique in this and other biological systems is discussed.

Burlage, Robert S.; Heitzer, Armin; Digrazia, Philip M.

1991-01-01

343

Characterization of an anthraquinone fluor from the bioluminescent, pelagic polychaete Tomopteris.  

Science.gov (United States)

Tomopteris is a cosmopolitan genus of polychaetes. Many species produce yellow luminescence in the parapodia when stimulated. Yellow bioluminescence is rare in the ocean, and the components of this luminescent reaction have not been identified. Only a brief description, half a century ago, noted fluorescence in the parapodia with a remarkably similar spectrum to the bioluminescence, which suggested that it may be the luciferin or terminal light-emitter. Here, we report the isolation of the fluorescent yellow-orange pigment found in the luminous exudate and in the body of the animals. Liquid chromatography-mass spectrometry revealed the mass to be 270 m/z with a molecular formula of C(15)H(10)O(5), which ultimately was shown to be aloe-emodin, an anthraquinone previously found in plants. We speculate that aloe-emodin could be a factor for resonant-energy transfer or the oxyluciferin for Tomopteris bioluminescence. PMID:24760626

Francis, Warren R; Powers, Meghan L; Haddock, Steven H D

2014-12-01

344

Study of real-time image denoising and hole-filling for micro-cantilever IR FPA imaging system  

Science.gov (United States)

This paper proposes and experimentally demonstrates a new denoising and hole-filling algorithm through discrete points removal and bilinear interpolation based on the bi-material cantilever FPA infrared imaging system. In practice, because of the limitation of FPA manufacturing process and optical readout system, the quality of obtained images is always not satisfying. A lot of noise and holes appear in the images, which restrict the application of the infrared imaging system. After analyzing the causes of noise and holes, an algorithm is presented to improve the quality of infrared images. Firstly, the statistic characteristics such as probability histograms of images with noise are analyzed in great detail. Then, IR images are denoised by the method of discrete points removal. Second, the holes are filled by bilinear interpolation. In this step, the reference points are found through partial derivative method instead of using the edge points of the holes simply. It can detect the real points effectively and enable the holes much closer to the true values. Finally, the algorithm is applied to different infrared images successfully. Experimental results show that the IR images can be denoised effectively and the SNRs are improved substantially. Meanwhile, the filling ratios of target holes reach as high as 95% and the visual quality is achieved well. It proves that the algorithm has the advantages of high speed, great precision and easy implement. It is a highly efficient real-time image processing algorithm for bi-material micro-cantilever FPA infrared imaging system.

Feng, Yun; Zhao, Yuejin; Dong, Liquan; Liu, Ming; Liu, Xiaohua; Li, Xiaomeng; Zhao, Zhu; Yu, Xiaomei; Hui, Mei; Wu, Hong

2014-10-01

345

a Study of the Bioluminescence of Larger Zooplankton and the Effects of Low-Level Light Changes on Their Behavior.  

Science.gov (United States)

A bio-optical study was undertaken to quantify the relationships which exist between counter-illuminating organisms and the downwelling spectral light field in which they exist. The basic hypothesis behind counter-illumination is that the animal emits light using ventrally-oriented photophores to disrupt or eliminate the shadowed area on ventral surfaces. An organism lacking photophores sharply silhouettes against the highly directional downwelling irradiance, whereas by distributing photophores over the ventral surface of the body and closely matching the spectral and intensity characteristics of the downwelling light, this silhouette is obscured. Analysis carried out on changes in vertical distribution patterns in response to low-level intensity changes in ambient surface light suggested that diel migrating organisms begin to shift vertically in the water column when surface scalar irradiance decreased below or increased above 1.0 times10^{-2} muEin m^{-2} sec^ {-1}. Maximum aggregations of organisms, as defined by MOCNESS net sampling or single-frequency acoustic backscatter, appeared to remain within definable in situ blue-green isolume ranges varying less than a factor of ten throughout each night. Comparisons made between organism counter-illumination capacity and modeled in situ downwelling irradiance levels suggested that euphausiids, decapods and myctophids use between 1-10 percent of their maximum counter-illumination capacity to match the ambient downwelling light conditions. Modeling also suggested that up to 40 percent of the maximum measured bioluminescence output is required to match ambient irradiance in the shallower surface zones where aggregations of copepods, potential food sources, were commonly found at night. An optical study to quantify the radiative transfer of bioluminescence from a point source revealed that non -isotropic point sources produce radiance patterns that cannot be simply explained by inverse square losses. Therefore simple inverse-square estimates of bioluminescent propagation loss rates from organisms in the ocean are an oversimplification of the radiative transfer processes that occur when these emissions occur. Additionally, in evaluating counter-illumination, the distance of the receptor, such as the eyes of a potential predator, is critical in determining the effectiveness of the organisms in matching the uniform light field of their surrounding environment and ultimately avoiding detection and predation.

van Keuren, Jeffrey Robert

346

Enhancing the survival of grafted cardiac stem cells for long-term imaging  

International Nuclear Information System (INIS)

Heat shock treatment is known to induce the protection for cells from various environmental insults. Akt (protein kinase B) - with anti-apoptotic activity - has presently been reemerged as a critical enzyme in several signal transduction pathways involved in cell proliferation and programmed cell death. We hypothesized that thermotic treatment and Akt activity in genetically modified cardiomyoblasts would improve their survival after transplantation. Embryonic rat H9c2 cardiomyoblasts were simultaneously transfected with adenovirus containing luciferase reporter gene (MOl 50) and another containing Akt gene [MOl (0 100) ]. 5x106 harvested cells were i.m. implanted into murine skeletal muscles. Bioluminescence imaging was acquired for everyday and luciferase assay was performed to validate the imaging data. For thermotic challenge, adenovirus-mediated flue expressing H9c2 cells were subjected to great heat of 42 .deg. C for 1 hr and re-cultured at 37 .deg. C for 18 hours. Expression of heat shock protein in cells was detected in vitro by Western-blotting. 5x106 normal and shocked cells were implanted into mouse thigh (n = 5) and the animals were imaged with bioluminescence imaging system. In vitro evidences showed a high level expression of Akt and HSP in transfected H9c2 cells. Animals carrying Akt expressed bioluminescence signals until day 34 of post-implantation. The Flue activity was significantly higher in the shocked H9c2 cell-implanted rats and detected over 102 cell-implanted rats and detected over 10 days as compared with the control group. The graft cell death was reduced by 73% at day 2 (1.46+ 10-7 p/s/cm2/sr), 51% at day 3 (1.02+10-7 p/s/cm2/sr), and 8% at day 10 (1.62+ 10-6 p/s/cm2/sr). We revealed here improvement of donor cell's survival induced by the anti-apoptotic means of Akt genetic therapy or heat shock. Utility of bioluminescence imaging resulted in a potential to noninvasively and repetitively monitor implanted cardiac myoblasts over time

347

Molecular imaging of glycogen synthase kinase-3beta and casein kinase-1alpha kinases.  

Science.gov (United States)

Glycogen synthase kinase-3beta (GSK3beta) and casein kinase-1alpha (CK1alpha) are multifunctional kinases that play critical roles in the regulation of a number of cellular processes. In spite of their importance, molecular imaging tools for noninvasive and real-time monitoring of their kinase activities have not been devised. Here we report development of the bioluminescent GSK3beta and CK1alpha reporter (BGCR) based on firefly luciferase complementation. Treatment of SW620 cells stably expressing the reporter with inhibitors of GSK3beta (SB415286 and LiCl) or CK1alpha (CKI-7) resulted in dose- and time-dependent increases in BGCR activity that were validated using Western blotting. No increase in bioluminescence was observed in the case of S37A mutant (GSK3beta inhibitors) or S45A mutant (CKI-7), demonstrating the specificity of the reporter. Imaging of mice tumor xenograft generated with BGCR-expressing SW620 cells following treatment with LiCl showed unique oscillations in GSK3beta activity that were corroborated by phosphorylated GSK3beta immunoblotting. Taken together, the BGCR is a novel molecular imaging tool that reveals unique insight into GSK3beta and CK1alpha kinase activities and may provide a powerful tool in experimental therapeutics for rapid optimization of dose and schedule of targeted therapies and for monitoring therapeutic response. PMID:20561505

Nyati, Shyam; Ranga, Rajesh; Ross, Brian D; Rehemtulla, Alnawaz; Bhojani, Mahaveer Swaroop

2010-10-15

348

Ready for prime time? Dual tracer PET and SPECT imaging  

OpenAIRE

Dual isotope single photon emission computed tomography (SPECT) and dual tracer positron emission tomography (PET) imaging have great potential in clinical and molecular applications in the pediatric as well as the adult populations in many areas of brain, cardiac, and oncologic imaging as it allows the exploration of different physiological and molecular functions (e.g., perfusion, neurotransmission, metabolism, apoptosis, angiogenesis) under the same physiological and physical conditions. T...

Fakhri, Georges El

2012-01-01

349

Generation of synthetic but visually realistic time series of cardiac images combining a biophysical model and clinical images.  

Science.gov (United States)

We propose a new approach for the generation of synthetic but visually realistic time series of cardiac images based on an electromechanical model of the heart and real clinical 4-D image sequences. This is achieved by combining three steps. The first step is the simulation of a cardiac motion using an electromechanical model of the heart and the segmentation of the end diastolic image of a cardiac sequence. We use biophysical parameters related to the desired condition of the simulated subject. The second step extracts the cardiac motion from the real sequence using nonrigid image registration. Finally, a synthetic time series of cardiac images corresponding to the simulated motion is generated in the third step by combining the motion estimated by image registration and the simulated one. With this approach, image processing algorithms can be evaluated as we know the ground-truth motion underlying the image sequence. Moreover, databases of visually realistic images of controls and patients can be generated for which the underlying cardiac motion and some biophysical parameters are known. Such databases can open new avenues for machine learning approaches. PMID:23014716

Prakosa, Adityo; Sermesant, Maxime; Delingette, Hervé; Marchesseau, Stéphanie; Saloux, Eric; Allain, Pascal; Villain, Nicolas; Ayache, Nicholas

2013-01-01

350

Contribution of Reflection Terahertz Time Domain-Imaging (THz-TDI) to Imaging Analysis of Artworks  

DEFF Research Database (Denmark)

Different kind s of artefacts (easel painting, panel paintings and Asian lacquerwares) have been scanned by THz - TDI and results have been compared with those obtained by others standard imaging techniques (x-ray radiography, cross sectional imaging, technical photography) .

Dandolo, Corinna Ludovica Koch; Fukunaga, Kaori

351

An image scanner for real time analysis of spark chamber images  

International Nuclear Information System (INIS)

The notes describes the semiautomatic scanning system at LNF for the analysis of spark chamber images. From the projection of the images on the scanner table, the trajectory in the real space is reconstructed

352

The application of superweak bioluminescence on freshness degree of chicken egg  

International Nuclear Information System (INIS)

The luminescence of chicken egg in storage is studied by a detection system of superweak bioluminescence. The results show that egg has the strongest vigour on the third day after it is laid, subsequently the luminescence presents decay with oscillation. These eggs, which have been stored for 3 days, are most suitable for hatching. Different eggs have different luminescence intensities depending on the vigour of the egg. The stronger the vigour of the egg is, the more intensive the luminescence is. Superweak bioluminescence as a comprehensive index of biology and biochemistry response can be used for inspecting the freshness degree of the egg, and the test is nondestructive and sensitive

353

Kidney stone imaging with 3D ultra-short echo time (UTE) magnetic resonance imaging. A phantom study.  

Science.gov (United States)

Computed tomography (CT) is the current gold standard for imaging kidney stones, albeit at the cost of radiation exposure. Conventional magnetic resonance imaging (MRI) sequences are insensitive to detecting the stones because of their appearance as a signal void. With the development of 2D ultra-short echo-time (UTE) MRI sequences, it becomes possible to image kidney stones in vitro. In this work, we optimize and implement a modified 3D UTE MRI sequence for imaging kidney stones embedded in agarose phantoms mimicking the kidney tissue and in urine phantoms at 3.0T. The proposed technique is capable of imaging the stones with high spatial resolution in a short scan time. PMID:25570462

Ibrahim, El-Sayed H; Pooley, Robert A; Bridges, Mellena D; Cernigliaro, Joseph G; Haley, William E

2014-01-01

354

An approach to a pseudo real-time image processing engine for hyperspectral imaging  

OpenAIRE

Hyperspectral imaging provides an alternative way of increasing the accuracy by adding another dimension: the wavelength. Recently, hyperspectral imaging is also finding its way into many more applications, ranging from medical imaging in endoscopy for cancer detection to quality control in the sorting of fruit and vegetables. But effective use of hyperspectral imaging requires an understanding of the nature and limitations of the data and of various strategies for processing and interpreting...

Abed Abedniya; Sahar Sabbaghi Mahmouei; Dr. Shattri Mansor

2010-01-01

355

Quantitative Characterization of Super-Resolution Infrared Imaging Based on Time-Varying Focal Plane Coding  

Science.gov (United States)

High resolution infrared image has been the goal of an infrared imaging system. In this paper, a super-resolution infrared imaging method using time-varying coded mask is proposed based on focal plane coding and compressed sensing theory. The basic idea of this method is to set a coded mask on the focal plane of the optical system, and the same scene could be sampled many times repeatedly by using time-varying control coding strategy, the super-resolution image is further reconstructed by sparse optimization algorithm. The results of simulation are quantitatively evaluated by introducing the Peak Signal-to-Noise Ratio (PSNR) and Modulation Transfer Function (MTF), which illustrate that the effect of compressed measurement coefficient r and coded mask resolution m on the reconstructed image quality. Research results show that the proposed method will promote infrared imaging quality effectively, which will be helpful for the practical design of new type of high resolution ! infrared imaging systems.

Wang, X.; Yuan, Y.; Zhang, J.; Chen, Y.; Cheng, Y.

2014-10-01

356

Visualizing real-time influenza virus infection, transmission and protection in ferrets.  

Science.gov (United States)

Influenza transmission efficiency in ferrets is vital for risk-assessment studies. However, the inability to monitor viral infection and transmission dynamics in real time only provides a glimpse into transmissibility. Here we exploit a replication-competent influenza reporter virus to investigate dynamics of infection/transmission in ferrets. Bioluminescent imaging of ferrets infected with A/California/04/2009 H1N1 virus (CA/09) encoding NanoLuc (NLuc) luciferase provides the first real-time snapshot of influenza infection/transmission. Luminescence in the respiratory tract and in less well-characterized extra-pulmonary sites is observed, and imaging identifies infections in animals that would have otherwise been missed by traditional methods. Finally, the reporter virus significantly increases the speed and sensitivity of virological and serological assays. Thus, bioluminescent imaging of influenza infections rapidly determines intra-host dissemination, inter-host transmission and viral load, revealing infection dynamics and pandemic potential of the virus. These results have important implications for antiviral drug susceptibility, vaccine efficacy, transmissibility and pathogenicity studies. PMID:25744559

Karlsson, Erik A; Meliopoulos, Victoria A; Savage, Chandra; Livingston, Brandi; Mehle, Andrew; Schultz-Cherry, Stacey

2015-01-01

357

Specific expression of bioluminescence reporter gene in cardiomyocyte regulated by tissue specific promoter  

International Nuclear Information System (INIS)

As the human heart is not capable of regenerating the great numbers of cardiac cells that are lost after myocardial infarction, impaired cardiac function is the inevitable result of ischemic disease. Recently, human embryonic stem cells (hESCs) have gained popularity as a potentially ideal cell candidate for tissue regeneration. In particular, hESCs are capable of cardiac lineage-specific differentiation and confer improvement of cardiac function following transplantation into animal models. Although such data are encouraging, the specific strategy for in vivo and non-invasive detection of differentiated cardiac lineage is still limited. Therefore, in the present study, we established the gene construction in which the optical reporter gene Firefly luciferase was controlled by Myosin Heavy Chain promoter for specific expressing in heart cells. The vector consisting of - MHC promoter and a firefly luciferase coding sequence flanked by full-length bovine growth hormone (BGH) 3'-polyadenylation sequence based on pcDNA3.1- vector backbone. To test the specific transcription of this promoter in g of MHC-Fluc or CMV-Flue (for control) plasmid DNA in myocardial tissue, 20 phosphate-buffered saline was directly injected into mouse myocardium through a midline sternotomy and liver. After 1 week of injection, MHC-Fluc expression was detected from heart region which was observed under cooled CCD camera of in vivo imaging system but not from liver. In control group injected with rom liver. In control group injected with CMV-Flue, the bioluminescence was detected from all these organs. The expression of Flue under control of Myosin Heavy Chain promoter may become a suitable optical reporter gene for stem cell-derived cardiac lineage differentiation study

358

Specific expression of bioluminescence reporter gene in cardiomyocyte regulated by tissue specific promoter  

Energy Technology Data Exchange (ETDEWEB)

As the human heart is not capable of regenerating the great numbers of cardiac cells that are lost after myocardial infarction, impaired cardiac function is the inevitable result of ischemic disease. Recently, human embryonic stem cells (hESCs) have gained popularity as a potentially ideal cell candidate for tissue regeneration. In particular, hESCs are capable of cardiac lineage-specific differentiation and confer improvement of cardiac function following transplantation into animal models. Although such data are encouraging, the specific strategy for in vivo and non-invasive detection of differentiated cardiac lineage is still limited. Therefore, in the present study, we established the gene construction in which the optical reporter gene Firefly luciferase was controlled by Myosin Heavy Chain promoter for specific expressing in heart cells. The vector consisting of - MHC promoter and a firefly luciferase coding sequence flanked by full-length bovine growth hormone (BGH) 3'-polyadenylation sequence based on pcDNA3.1- vector backbone. To test the specific transcription of this promoter in g of MHC-Fluc or CMV-Flue (for control) plasmid DNA in myocardial tissue, 20 phosphate-buffered saline was directly injected into mouse myocardium through a midline sternotomy and liver. After 1 week of injection, MHC-Fluc expression was detected from heart region which was observed under cooled CCD camera of in vivo imaging system but not from liver. In control group injected with CMV-Flue, the bioluminescence was detected from all these organs. The expression of Flue under control of Myosin Heavy Chain promoter may become a suitable optical reporter gene for stem cell-derived cardiac lineage differentiation study.

Nguyen, Vu Hong; Tae, Seong Ho; Le, Nguyen Uyen Chi; Min, Jung Joon [Chonnam National University Medical School, Gwangju (Korea, Republic of)

2007-07-01

359

Instrumentation in Diffuse Optical Imaging  

OpenAIRE

Diffuse optical imaging is highly versatile and has a very broad range of applications in biology and medicine. It covers diffuse optical tomography, fluorescence diffuse optical tomography, bioluminescence, and a number of other new imaging methods. These methods of diffuse optical imaging have diversified instrument configurations but share the same core physical principle – light propagation in highly diffusive media, i.e., the biological tissue. In this review, the author summarizes the...

Xiaofeng Zhang

2014-01-01

360

AIDI: An adaptive image denoising FPGA-based IP-core for real-time applications  

OpenAIRE

The presence of noise in images can significantly impact the performances of digital image processing and computer vision algorithms. Thus, it should be removed to improve the robustness of the entire processing flow. The noise estimation in an image is also a key factor, since, to be more effective, algorithms and denoising filters should be tuned to the actual level of noise. Moreover, the complexity of these algorithms brings a new challenge in real-time image processing applications, requ...

Trotta, Pascal; Rolfo, Daniele; Prinetto, Paolo Ernesto; Di Carlo, Stefano

2013-01-01

361

A fiducial detection algorithm for real-time image guided IMRT based on simultaneous MV and kV imaging  

International Nuclear Information System (INIS)

The advantage of highly conformal dose techniques such as 3DCRT and IMRT is limited by intrafraction organ motion. A new approach to gain near real-time 3D positions of internally implanted fiducial markers is to analyze simultaneous onboard kV beam and treatment MV beam images (from fluoroscopic or electronic portal image devices). Before we can use this real-time image guidance for clinical 3DCRT and IMRT treatments, four outstanding issues need to be addressed. (1) How will fiducial motion blur the image and hinder tracking fiducials? kV and MV images are acquired while the tumor is moving at various speeds. We find that a fiducial can be successfully detected at a maximum linear speed of 1.6 cm/s. (2) How does MV beam scattering affect kV imaging? We investigate this by varying MV field size and kV source to imager distance, and find that common treatment MV beams do not hinder fiducial detection in simultaneous kV images. (3) How can one detect fiducials on images from 3DCRT and IMRT treatment beams when the MV fields are modified by a multileaf collimator (MLC)? The presented analysis is capable of segmenting a MV field from the blocking MLC and detecting visible fiducials. This enables the calculation of nearly real-time 3D positions of markers during a real treatment. (4) Is the analysis fast enough to track fiducials in nearly real time? Multiple methods are adopted to predict marker positions and reduce search regions. The average detection time per frame fos. The average detection time per frame for three markers in a 1024x768 image was reduced to 0.1 s or less. Solving these four issues paves the way to tracking moving fiducial markers throughout a 3DCRT or IMRT treatment. Altogether, these four studies demonstrate that our algorithm can track fiducials in real time, on degraded kV images (MV scatter), in rapidly moving tumors (fiducial blurring), and even provide useful information in the case when some fiducials are blocked from view by the MLC. This technique can provide a gating signal or be used for intra-fractional tumor tracking on a Linac equipped with a kV imaging system. Any motion exceeding a preset threshold can warn the therapist to suspend a treatment session and reposition the patient

362

Real-time image transmission and interferometry through a distorting medium using two phase conjugators.  

Science.gov (United States)

A phase-conjugate geometry with two photorefractive crystals is demonstrated. It can be used for real-time one- or two-way image transmission through a distorting medium and for real-time holographic interferometry. PMID:20820329

Sun, Y; Moharam, M G

1993-04-10

363

A symmetrical image encryption scheme in wavelet and time domain  

Science.gov (United States)

There has been an increasing concern for effective storages and secure transactions of multimedia information over the Internet. Then a great variety of encryption schemes have been proposed to ensure the information security while transmitting, but most of current approaches are designed to diffuse the data only in spatial domain which result in reducing storage efficiency. A lightweight image encryption strategy based on chaos is proposed in this paper. The encryption process is designed in transform domain. The original image is decomposed into approximation and detail components using integer wavelet transform (IWT); then as the more important component of the image, the approximation coefficients are diffused by secret keys generated from a spatiotemporal chaotic system followed by inverse IWT to construct the diffused image; finally a plain permutation is performed for diffusion image by the Logistic mapping in order to reduce the correlation between adjacent pixels further. Experimental results and performance analysis demonstrate the proposed scheme is an efficient, secure and robust encryption mechanism and it realizes effective coding compression to satisfy desirable storage.

Luo, Yuling; Du, Minghui; Liu, Junxiu

2015-02-01

364

One-Shot Color Astronomical Imaging In Less Time, For Less Money!  

CERN Document Server

Anyone who has seen recent pictures of the many wondrous objects in space has surely been amazed by the stunning color images. Trying to capture images like these through your own telescope has always seemed too time-consuming, expensive, and complicated. However, with improvements in affordable, easy-to-use CCD imaging technology, you can now capture amazing images yourself. With today's improved "one-shot" color imagers, high-quality images can be taken in a fraction of the time and at a fraction of the cost, right from your own backyard. This book will show you how to harness the power of today's computerized telescopes and entry-level imagers to capture spectacular images that you can share with family and friends. It covers such topics as - evaluating your existing equipment, choosing the right imager, finding targets to image, telescope alignment, focusing and framing the image, exposure times, aligning and stacking multiple frames, image calibration, and enhancement techniques! - how to expand the numb...

Kennedy, L A

2012-01-01

365

Effects of salinity, pH and temperature on the re-establishment of bioluminescence and copper or SDS toxicity in the marine dinoflagellate Pyrocystis lunula using bioluminescence as an endpoint  

Energy Technology Data Exchange (ETDEWEB)

The bioluminescence assay is not sensitive to small changes in pH, temperature or salinity. - Pyrocystis lunula is a unicellular, marine, photoautotrophic, bioluminescent dinoflagellate. This organism is used in the Lumitox[reg] bioassay with inhibition of bioluminescence re-establishment as the endpoint. Experiments determined if acute changes in pH, salinity, or temperature had an effect on the organisms' ability to re-establish bioluminescence, or on the bioassay's potential to detect sodium dodecyl sulfate (SDS) and copper toxicity. The re-establishment of bioluminescence itself was not very sensitive to changes in pH within the pH 6-10 range, though reducing pH from 8 to levels below 6 decreased this capacity. Increasing the pH had little effect on Cu or SDS toxicity, but decreasing the pH below 7 virtually eliminated the toxicity of either compound in the bioassay. Lowering the salinity from 33 to 27%o or less resulted in a substantial decrease in re-establishment of bioluminescence, while increasing the salinity to 43 or 48 %o resulted in a small decline. Salinity had little influence on the bioassay's quantification of Cu toxicity, while the data showed a weak negative relationship between SDS toxicity and salinity. Re-establishment of bioluminescence showed a direct dependence on temperature, but only at 10 deg. C did temperature have an obvious effect on the toxicity of Cu in this bioassay.

Craig, Jaquelyn M.; Klerks, Paul L.; Heimann, Kirsten; Waits, Juliann L

2003-09-01

366

Effects of salinity, pH and temperature on the re-establishment of bioluminescence and copper or SDS toxicity in the marine dinoflagellate Pyrocystis lunula using bioluminescence as an endpoint  

International Nuclear Information System (INIS)

The bioluminescence assay is not sensitive to small changes in pH, temperature or salinity. - Pyrocystis lunula is a unicellular, marine, photoautotrophic, bioluminescent dinoflagellate. This organism is used in the Lumitox[reg] bioassay with inhibition of bioluminescence re-establishment as the endpoint. Experiments determined if acute changes in pH, salinity, or temperature had an effect on the organisms' ability to re-establish bioluminescence, or on the bioassay's potential to detect sodium dodecyl sulfate (SDS) and copper toxicity. The re-establishment of bioluminescence itself was not very sensitive to changes in pH within the pH 6-10 range, though reducing pH from 8 to levels below 6 decreased this capacity. Increasing the pH had little effect on Cu or SDS toxicity, but decreasing the pH below 7 virtually eliminated the toxicity of either compound in the bioassay. Lowering the salinity from 33 to 27%o or less resulted in a substantial decrease in re-establishment of bioluminescence, while increasing the salinity to 43 or 48 %o resulted in a small decline. Salinity had little influence on the bioassay's quantification of Cu toxicity, while the data showed a weak negative relationship between SDS toxicity and salinity. Re-establishment of bioluminescence showed a direct dependence on temperature, but only at 10 deg. C did temperature have an obvious effect on the toxicity of Cu in this bioassay

367

Optimal scan timing of hepatic arterial-phase imaging of hypervascular hepatocellular carcinoma determined by multiphasic fast CT imaging technique  

Energy Technology Data Exchange (ETDEWEB)

Background: A new multiphasic fast imaging technique, known as volume helical shuttle technique, is a breakthrough for liver imaging that offers new clinical opportunities in dynamic blood flow studies. This technique enables virtually real-time hemodynamics assessment by shuttling the patient cradle back and forth during serial scanning. Purpose: To determine optimal scan timing of hepatic arterial-phase imaging for detecting hypervascular hepatocellular carcinoma (HCC) with maximum tumor-to-liver contrast by volume helical shuttle technique. Material and Methods: One hundred and one hypervascular HCCs in 50 patients were prospectively studied by 64-channel multidetector-row computed tomography (MDCT) with multiphasic fast imaging technique. Contrast medium containing 600 mg iodine per kg body weight was intravenously injected for 30 s. Six seconds after the contrast arrival in the abdominal aorta detected with bolus tracking, serial 12-phase imaging of the whole liver was performed during 24-s breath-holding with multiphasic fast imaging technique during arterial phase. By placing regions of interest in the abdominal aorta, portal vein, liver parenchyma, and hypervascular HCCs on the multiphase images, time-density curves of anatomical regions and HCCs were composed. Timing of maximum tumor-to-liver contrast after the contrast arrival in the abdominal aorta was determined. Results: For the detection of hypervascular HCC at arterial phase, mean time and value of maximum tumor-to-liver contrast after the contrast arrival were 21 s and 38.0 HU, respectively. Conclusion: Optimal delay time for the hepatic arterial-phase imaging maximizing the contrast enhancement of hypervascular HCCs was 21 s after arrival of contrast medium in the abdominal aorta.

Kagawa, Yuki; Okada, Masahiro; Yagyu, Yukinobu; Kumano, Seishi; Murakami, Takamichi [Dept. of Radiology, Kinki Univ. Faculty of Medicine, Osaka (Japan)], e-mail: murakami@med.kindai.ac.jp; Kanematsu, Masayuki [Dept. of Radiology, Gifu Univ., School of Medicine, Gifu (Japan); Kudo, Masayuki [CT Research JP, GE Healthcare JP Corporation, Tokyo (Japan)

2013-10-15

368

An Internet and Intranet Based Real Time Medical Imaging System  

Directory of Open Access Journals (Sweden)

Full Text Available Today computer is an essential part of our life. The computer database is used for medical decision making. Doctors basically used to take decision on particular diesis on the help of old and current history of the patients or same diesis procured by other patients. This paper describe a tool developed in java/j2EE which enables the doctors to retrieved old record of same dieses treatment using internet and even allow them view medical image of blood slides, ECG, CT-scan, X-Ray etc. even allow them to mark and/or zoom important area of the image. It is secure and multi party medical image database consultant system.

Prashant Kumar

2013-09-01

369

Measuring the complexity of design in real-time imaging software  

Science.gov (United States)

Due to the intricacies in the algorithms involved, the design of imaging software is considered to be more complex than non-image processing software (Sangwan et al, 2005). A recent investigation (Larsson and Laplante, 2006) examined the complexity of several image processing and non-image processing software packages along a wide variety of metrics, including those postulated by McCabe (1976), Chidamber and Kemerer (1994), and Martin (2003). This work found that it was not always possible to quantitatively compare the complexity between imaging applications and nonimage processing systems. Newer research and an accompanying tool (Structure 101, 2006), however, provides a greatly simplified approach to measuring software complexity. Therefore it may be possible to definitively quantify the complexity differences between imaging and non-imaging software, between imaging and real-time imaging software, and between software programs of the same application type. In this paper, we review prior results and describe the methodology for measuring complexity in imaging systems. We then apply a new complexity measurement methodology to several sets of imaging and non-imaging code in order to compare the complexity differences between the two types of applications. The benefit of such quantification is far reaching, for example, leading to more easily measured performance improvement and quality in real-time imaging code.

Sangwan, Raghvinder S.; Vercellone-Smith, Pamela; Laplante, Phillip A.

2007-02-01

370

Two-photon axotomy and time-lapse confocal imaging in live zebrafish embryos  

OpenAIRE

Zebrafish have long been utilized to study the cellular and molecular mechanisms of development by time-lapse imaging of the living transparent embryo. Here we describe a method to mount zebrafish embryos for long-term imaging and demonstrate how to automate the capture of time-lapse images using a confocal microscope. We also describe a method to create controlled, precise damage to individual branches of peripheral sensory axons in zebrafish using the focused power of a femtosecond laser ...

O Brien, Georgeann S.; Rieger, Sandra; Martin, Seanna M.; Cavanaugh, Ann M.; Portera-cailliau, Carlos; Sagasti, Alvaro

2009-01-01

371

A high-resolution, four-band SAR testbed with real-time image formation  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the Twin-Otter SAR Testbed developed at Sandia National Laboratories. This SAR is a flexible, adaptable testbed capable of operation on four frequency bands: Ka, Ku, X, and VHF/UHF bands. The SAR features real-time image formation at fine resolution in spotlight and stripmap modes. High-quality images are formed in real time using the overlapped subaperture (OSA) image-formation and phase gradient autofocus (PGA) algorithms.

Walker, B.; Sander, G.; Thompson, M.; Burns, B.; Fellerhoff, R.; Dubbert, D.

1996-03-01

372

Feasibility study: real-time 3-D ultrasound imaging of the brain.  

Science.gov (United States)

We tested the feasibility of real-time, 3-D ultrasound (US) imaging in the brain. The 3-D scanner uses a matrix phased-array transducer of 512 transmit channels and 256 receive channels operating at 2.5 MHz with a 15-mm diameter footprint. The real-time system scans a 65 degrees pyramid, producing up to 30 volumetric scans per second, and features up to five image planes as well as 3-D rendering, 3-D pulsed-wave and color Doppler. In a human subject, the real-time 3-D scans produced simultaneous transcranial horizontal (axial), coronal and sagittal image planes and real-time volume-rendered images of the gross anatomy of the brain. In a transcranial sheep model, we obtained real-time 3-D color flow Doppler scans and perfusion images using bolus injection of contrast agents into the internal carotid artery. PMID:15582236

Smith, Stephen W; Chu, Kengyeh; Idriss, Salim F; Ivancevich, Nikolas M; Light, Edward D; Wolf, Patrick D

2004-10-01

373

Time-of-flight neutron imaging at a continuous source: Proof of principle using a scintillator CCD imaging detector  

Energy Technology Data Exchange (ETDEWEB)

Energy resolved imaging has recently gained attention for the potential of spatially resolved texture, crystallographic phase and strain investigations. Especially a time-of-flight (TOF) approach that takes maximum advantage of the new generation of pulsed spallation neutron sources is currently in the focus of investigations. Here, we present results of corresponding TOF measurements recorded at the continuous source of Helmholtz Center Berlin. The critical component for TOF imaging is however the availability of a high resolution imaging detector capable of the required time resolution. Here, a gated time-integrating detector without the corresponding continuous time resolution has been used and the measurements therefore have to be interpreted as proof-of-principle experiments as will be discussed. Measurements of different series of samples revealing structural differences related to their crystalline structure will be presented as well as a strain measurement on a dieless drawn wire.

Strobl, M., E-mail: strobl@helmholtz-berlin.de [Helmholtzzentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Hilger, A.; Boin, M.; Kardjilov, N.; Wimpory, R.; Clemens, D. [Helmholtzzentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Muehlbauer, M.; Schillinger, B. [Technische Universitaet Muenchen, FRM II and Physics E21, Lichtenbergstr.1, 85748 Garching, Munich (Germany); Wilpert, T.; Schulz, C.; Rolfs, K. [Helmholtzzentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Davies, C.M. [Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); O' Dowd, N.; Tiernan, P. [Materials and Surface Science Institute, University of Limerick, Limerick (Ireland); Manke, I. [Helmholtzzentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany)

2011-09-21

374

Automated, real time extraction of fundus images from slit lamp fundus biomicroscope video image sequences  

OpenAIRE

AIMS—Slit lamp fundus biomicroscopy allows for high magnification, stereoscopic diagnosis, and treatment of macular diseases. Variable contrast, narrow field of view, and specular reflections arising from the cornea, sclera, and examining lens reduce image quality; these images are of limited clinical utility for diagnosis, treatment planning, and photodocumentation when compared with fundus camera images. Algorithms are being developed to segment fundus imagery from slit lamp biomicroscopi...

Madjarov, B.; Berger, J.

2000-01-01

375

Implementing capon beamforming on a GPU for real-time cardiac ultrasound imaging.  

Science.gov (United States)

Capon beamforming is associated with a high computational complexity, which limits its use as a real-time method in many applications. In this paper, we present an implementation of the Capon beamformer that exhibits realtime performance when applied in a typical cardiac ultrasound imaging setting. To achieve this performance, we make use of the parallel processing power found in modern graphics processing units (GPUs), combined with beamspace processing to reduce the computational complexity as the number of array elements increases. For a three-dimensional beamspace, we show that processing rates supporting real-time cardiac ultrasound imaging are possible, meaning that images can be processed faster than the image acquisition rate for a wide range of parameters. Image quality is investigated in an in vivo cardiac data set. These results show that Capon beamforming is feasible for cardiac ultrasound imaging, providing images with improved lateral resolution both in element-space and beamspace. PMID:24402897

Åsen, Jon Petter; Buskenes, Jo Inge; Colombo Nilsen, Carl-Inge; Austeng, Andreas; Holm, Sverre

2014-01-01

376

Fusion imaging of real-time ultrasonography with CT or MRI for hepatic intervention  

Directory of Open Access Journals (Sweden)

Full Text Available

With the technical development of ultrasonography (US, electromagnetic tracking-based fusion imaging of real-time US and computed tomography/magnetic resonance (CT/MR images has been used for percutaneous hepatic intervention such as biopsy and radiofrequency ablation (RFA. Because of the fusion imaging technique, the fused CT or MR images show the same plane and move synchronously while performing real-time US. With this information, fusion imaging can enhance lesion detectability and reduce the false positive detection of focal hepatic lesions with poor sonographic conspicuity. Three-dimensional US can also be fused with realtime US for the percutaneous RFA of liver tumors requiring overlapping ablation. When fusion imaging is not sufficient for identifying small focal hepatic lesions, contrast-enhanced US can be added to fusion imaging.

Min Woo Lee

2014-10-01

377

A Real Time Implementation of an Image Scaling Processor Using VLSI Technique  

Directory of Open Access Journals (Sweden)

Full Text Available Image scaling is a very important technique and has been widely used in many image processing applications. In applications where the scaling process must be performed at the display rather than at the CPU OR GPU, dedicated hardware implementation is necessary.Low-complexity image processing algorithms are necessary for VLSI implementation of real time applications. The image scaling algorithm of the proposed system consists of a sharpening spatial filter, a clamp filter, and a bilinear interpolation. Images are captured in real time by an image sensor and send to the FPGA along with the scaling parameter. Serial connectivity is provided to the FPGA and the scaled images are displayed on the PC. The filter combining, hardware sharing techniques of the bilinear interpolator and reconfigurable techniques has been used to reduce hardware costs.

Fathima Abdul Azeez*1

2014-04-01

378

Coherent time-reversal microwave imaging for the detection and localization of breast tissue malignancies  

Science.gov (United States)

This paper deals with the coherent processing of time-reversal operator for microwave imaging in the frequency domain. In frequency domain time-reversal imaging approach, images obtained for different frequency bins over ultrawideband are incoherently processed. In highly dense and cluttered medium, the signal subspace over each narrow frequency bin varies from that obtained using the complete ultrawideband. As a result, the detection and localization from noncoherent imaging approach is often inconclusive. In order to improve the stability of time-reversal microwave imaging, we propose coherent processing using novel focusing matrix approach. The proposed focusing matrix makes possible the time-reversal imaging technique to coherently process each frequency bin to yield a consistent signal subspace. The performance of coherent focusing is investigated when combined with time-reversal robust Capon beamformer (TR-RCB). We have used numerical experiments on breast cancer detection using finite difference time domain employing anatomically realistic numerical breast phantoms that contain varying amounts of dense fibroglandular tissue content. The imaging results indicate that the proposed coherent-TR-RCB could overcome the limitations of time-reversal imaging in a highly heterogeneous and cluttered medium.

Hossain, Md. Delwar; Mohan, Ananda Sanagavarapu

2015-02-01

379

Collinear two colour Kerr effect based time-gate for ballistic imaging  

CERN Document Server

A novel setup is presented for ballistic imaging using an efficient ultrafast Kerr effect based optical time-gate with gating times of the order of ~0.8 picoseconds. At first, the major drawbacks of the classical non-collinear optical setup are discussed. Then, the new collinear arrangement is proposed, which overcomes these issues and improves the achievable imaging spatial resolution and gate timings. Few preliminary results for ballistic imaging of liquid sprays/jets are presented for this arrangement. It is shown that using a solid state Kerr medium (GGG crystal), instead of the classical liquid CS$_2$, allows reduction in the opening time of the optical gate.

Purwar, Harsh; Rozé, Claude; Blaisot, Jean-Bernard

2015-01-01

380

Effects of heavy metals on the bioluminescence of the ophiuroid Amphipholis squamata: A field study  

International Nuclear Information System (INIS)

The aim of the present study was to investigate effects of heavy metals on the bioluminescence of A. squamata in the field. Therefore, ophiuroid populations were investigated along a pollution gradient in the Bay of Portman (Spain, Mediterranean) where 35 years of intensive mining activities resulted in a dramatic, contamination of the marine environment by heavy metals (Fe, Pb, Zn, Ag, Cd, Cu)

381

Molecular phylogeny of Neotropical bioluminescent beetles (Coleoptera: Elateroidea) in southern and central Brazil.  

Science.gov (United States)

Bioluminescence in beetles is found mainly in the Elateroidea superfamily (Elateridae, Lampyridae and Phengodidae). The Neotropical region accounts for the richest diversity of bioluminescent species in the world with about 500 described species, most occurring in the Amazon, Atlantic rainforest and Cerrado (savanna) ecosystems in Brazil. The origin and evolution of bioluminescence, as well as the taxonomic status of several Neotropical taxa in these families remains unclear. In order to contribute to a better understanding of the phylogeny and evolution of bioluminescent Elateroidea we sequenced and analyzed sequences of mitochondrial NADH2 and the nuclear 28S genes and of the cloned luciferase sequences of Brazilian species belonging to the following genera: (Lampyridae) Macrolampis, Photuris, Amydetes, Bicellonycha, Aspisoma, Lucidota, Cratomorphus; (Elateridae) Conoderus, Pyrophorus, Hapsodrilus, Pyrearinus, Fulgeochlizus; and (Phengodidae) Pseudophengodes, Phrixothrix, Euryopa and Brasilocerus. Our study supports a closer phylogenetic relationship between Elateridae and Phengodidae as other molecular studies, in contrast with previous morphologic and molecular studies that clustered Lampyridae/Phengodidae. Molecular data also supported division of the Phengodinae subfamily into the tribes Phengodini and Mastinocerini. The position of the genus Amydetes supports the status of the Amydetinae as a subfamily. The genus Euryopa is included in the Mastinocerini tribe within the Phengodinae/Phengodidae. PMID:23868199

Amaral, D T; Arnoldi, F G C; Rosa, S P; Viviani, V R

2014-08-01

382

Complete Genome Sequence of the Bioluminescent Marine Bacterium Vibrio harveyi ATCC 33843 (392 [MAV]).  

Science.gov (United States)

Vibrio harveyi is a Gram-negative marine ?-proteobacterium that is known to be a formidable pathogen of aquatic animals and is a model organism for the study of bacterial bioluminescence and quorum sensing. In this report, we describe the complete genome sequence of the most studied strain of this species: V. harveyi ATCC 33843 (392 [MAV]). PMID:25635019

Wang, Zheng; Hervey, W Judson; Kim, Seongwon; Lin, Baochuan; Vora, Gary J

2015-01-01

383

Image-Guided Radiotherapy in Near Real Time With Intensity-Modulated Radiotherapy Megavoltage Treatment Beam Imaging  

International Nuclear Information System (INIS)

Purpose: To utilize image-guided radiotherapy (IGRT) in near real time by obtaining and evaluating the online positions of implanted fiducials from continuous electronic portal imaging device (EPID) imaging of prostate intensity-modulated radiotherapy (IMRT) delivery. Methods and Materials: Upon initial setup using two orthogonal images, the three-dimensional (3D) positions of all implanted fiducial markers are obtained, and their expected two-dimensional (2D) locations in the beam's-eye-view (BEV) projection are calculated for each treatment field. During IMRT beam delivery, EPID images of the megavoltage treatment beam are acquired in cine mode and subsequently analyzed to locate 2D locations of fiducials in the BEV. Simultaneously, 3D positions are estimated according to the current EPID image, information from the setup portal images, and images acquired at other gantry angles (the completed treatment fields). The measured 2D and 3D positions of each fiducial are compared with their expected 2D and 3D setup positions, respectively. Any displacements larger than a predefined tolerance may cause the treatment system to suspend the beam delivery and direct the therapists to reposition the patient. Results: Phantom studies indicate that the accuracy of 2D BEV and 3D tracking are better than 1 mm and 1.4 mm, respectively. A total of 7330 images from prostate treatments were acquired and analyzed, showing a maximum 2D displacement of 6.7 mm and a maximum 3D displacementnt of 6.7 mm and a maximum 3D displacement of 6.9 mm over 34 fractions. Conclusions: This EPID-based, real-time IGRT method can be implemented on any external beam machine with portal imaging capabilities without purchasing any additional equipment, and there is no extra dose delivered to the patient.

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