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1

Real-Time Bioluminescence Imaging of Mixed Mycobacterial Infections  

Science.gov (United States)

Molecular analysis of infectious processes in bacteria normally involves construction of isogenic mutants that can then be compared to wild type in an animal model. Pathogenesis and antimicrobial studies are complicated by variability between animals and the need to sacrifice individual animals at specific time points. Live animal imaging allows real-time analysis of infections without the need to sacrifice animals, allowing quantitative data to be collected at multiple time points in all organs simultaneously. However, imaging has not previously allowed simultaneous imaging of both mutant and wild type strains of mycobacteria in the same animal. We address this problem by using both firefly (Photinus pyralis) and click beetle (Pyrophorus plagiophthalamus) red luciferases, which emit distinct bioluminescent spectra, allowing simultaneous imaging of two different mycobacterial strains during infection. We also demonstrate that these same bioluminescence reporters can be used to evaluate therapeutic efficacy in real-time, greatly facilitating our ability to screen novel antibiotics as they are developed. Due to the slow growth rate of mycobacteria, novel imaging technologies are a pressing need, since they can they can impact the rate of development of new therapeutics as well as improving our understanding of virulence mechanisms and the evaluation of novel vaccine candidates. PMID:25265287

Chang, MiHee; Anttonen, Katri P.; Cirillo, Suat L. G.; Francis, Kevin P.; Cirillo, Jeffrey D.

2014-01-01

2

Assessment of efficacy of antifungals against Aspergillus fumigatus: value of real-time bioluminescence imaging.  

Science.gov (United States)

Aspergillus fumigatus causes life-threatening infections, especially in immunocompromised patients. Common drugs for therapy of aspergillosis are polyenes, azoles, and echinocandins. However, despite in vitro efficacy of these antifungals, treatment failure is frequently observed. In this study, we established bioluminescence imaging to monitor drug efficacy under in vitro and in vivo conditions. In vitro assays confirmed the effectiveness of liposomal amphotericin B, voriconazole, and anidulafungin. Liposomal amphotericin B and voriconazole were fungicidal, whereas anidulafungin allowed initial germination of conidia that stopped elongation but allowed the conidia to remain viable. In vivo studies were performed with a leukopenic murine model. Mice were challenged by intranasal instillation with a bioluminescent reporter strain (5 × 10(5) and 2.5 × 10(5) conidia), and therapy efficacies of liposomal amphotericin B, voriconazole, and anidulafungin were monitored. For monotherapy, the highest treatment efficacy was observed with liposomal amphotericin B, whereas the efficacies of voriconazole and anidulafungin were strongly dependent on the infectious dose. When therapy efficacy was studied with different drug combinations, all combinations improved the rate of treatment success compared to that with monotherapy. One hundred percent survival was obtained for treatment with a combination of liposomal amphotericin B and anidulafungin, which prevented not only pulmonary infections but also infections of the sinus. In conclusion, combination therapy increases treatment success, at least in the murine infection model. In addition, our novel approach based on real-time imaging enables in vivo monitoring of drug efficacy in different organs during therapy of invasive aspergillosis. PMID:23587947

Galiger, Célimène; Brock, Matthias; Jouvion, Grégory; Savers, Amélie; Parlato, Marianna; Ibrahim-Granet, Oumaïma

2013-07-01

3

Noninvasive Bioluminescence Imaging in Small Animals  

Science.gov (United States)

There has been a rapid growth of bioluminescence imaging applications in small animal models in recent years, propelled by the availability of instruments, analysis software, reagents, and creative approaches to apply the technology in molecular imaging. Advantages include the sensitivity of the technique as well as its efficiency, relatively low cost, and versatility. Bioluminescence imaging is accomplished by sensitive detection of light emitted following chemical reaction of the luciferase enzyme with its substrate. Most imaging systems provide 2-dimensional (2D) information in rodents, showing the locations and intensity of light emitted from the animal in pseudo-color scaling. A 3-dimensional (3D) capability for bioluminescence imaging is now available, but is more expensive and less efficient; other disadvantages include the requirement for genetically encoded luciferase, the injection of the substrate to enable light emission, and the dependence of light signal on tissue depth. All of these problems make it unlikely that the method will be extended to human studies. However, in small animal models, bioluminescence imaging is now routinely applied to serially detect the location and burden of xenografted tumors, or identify and measure the number of immune or stem cells after an adoptive transfer. Bioluminescence imaging also makes it possible to track the relative amounts and locations of bacteria, viruses, and other pathogens over time. Specialized applications of bioluminescence also follow tissue-specific luciferase expression in transgenic mice, and monitor biological processes such as signaling or protein interactions in real time. In summary, bioluminescence imaging has become an important component of biomedical research that will continue in the future. PMID:18172337

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

2008-01-01

4

In vivo Dual Substrate Bioluminescent Imaging  

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Our understanding of how and when breast cancer cells transit from established primary tumors to metastatic sites has increased at an exceptional rate since the advent of in vivo bioluminescent imaging technologies 1-3. Indeed, the ability to locate and quantify tumor growth longitudinally in a single cohort of animals to completion of the study as opposed to sacrificing individual groups of animals at specific assay times has revolutionized how researchers investigate breast cancer metastas...

Wendt, Michael K.; Molter, Joseph; Flask, Christopher A.; Schiemann, William P.

2011-01-01

5

Bioluminescence imaging characteristics and application  

International Nuclear Information System (INIS)

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

6

Establishment of a Real-Time, Quantitative, and Reproducible Mouse Model of Staphylococcus Osteomyelitis Using Bioluminescence Imaging  

Science.gov (United States)

Osteomyelitis remains a serious problem in the orthopedic field. There are only a few animal models in which the quantity and distribution of bacteria can be reproducibly traced. Here, we established a real-time quantitative mouse model of osteomyelitis using bioluminescence imaging (BLI) without sacrificing the animals. A bioluminescent strain of Staphylococcus aureus was inoculated into the femurs of mice. The bacterial photon intensity (PI) was then sequentially measured by BLI. Serological and histological analyses of the mice were performed. The mean PI peaked at 3 days, and stable signals were maintained for over 3 months after inoculation. The serum levels of interleukin-6, interleukin-1?, and C-reactive protein were significantly higher in the infected mice than in the control mice on day 7. The serum monocyte chemotactic protein 1 level was also significantly higher in the infected group at 12 h than in the control group. A significantly higher proportion of granulocytes was detected in the peripheral blood of the infected group after day 7. Additionally, both acute and chronic histological manifestations were observed in the infected group. This model is useful for elucidating the pathophysiology of both acute and chronic osteomyelitis and to assess the effects of novel antibiotics or antibacterial implants. PMID:22104103

Funao, Haruki; Nagai, Shigenori; Sasaki, Aya; Hoshikawa, Tomoyuki; Aizawa, Mamoru; Okada, Yasunori; Chiba, Kazuhiro; Koyasu, Shigeo; Toyama, Yoshiaki; Matsumoto, Morio

2012-01-01

7

Bioluminescent imaging of Trypanosoma cruzi infection in Rhodnius prolixus  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Usually the analysis of the various developmental stages of Trypanosoma cruzi in the experimentally infected vertebrate and invertebrate hosts is based on the morphological observations of tissue fragments from animals and insects. The development of techniques that allow the imaging of animals infected with parasites expressing luciferase open up possibilities to follow the fate of bioluminescent parasites in infected vectors. Methods D-luciferin (60 ?g was injected into the hemocoel of the whole insect before bioluminescence acquisition. In dissected insects, the whole gut was incubated with D-luciferin in PBS (300 ?g/ml for ex vivo bioluminescence acquisition in the IVIS® Imaging System, Xenogen. Results Herein, we describe the results obtained with the luciferase gene integrated into the genome of the Dm28c clone of T. cruzi, and the use of these parasites to follow, in real time, the infection of the insect vector Rhodnius prolixus, by a non- invasive method. The insects were evaluated by in vivo bioluminescent imaging on the feeding day, and on the 7 th, 14 th, 21 st and 28 th days after feeding. To corroborate the bioluminescent imaging made in vivo, and investigate the digestive tract region, the insects were dissected. The bioluminescence emitted was proportional to the number of protozoans in regions of the gut. The same digestive tracts were also macerated to count the parasites in distinct morphological stages with an optical microscope, and for bioluminescence acquisition in a microplate using the IVIS® Imaging System. A positive correlation of parasite numbers and bioluminescence in the microplate was obtained. Conclusions This is the first report of bioluminescent imaging in Rhodnius prolixus infected with trypomastigotes of the Dm28c-luc stable strain, expressing firefly luciferase. In spite of the distribution limitations of the substrate (D-luciferin in the insect body, longitudinal evaluation of infected insects by bioluminescent imaging is a valuable tool. Bioluminescent imaging of the digestive tract infected with Dm28c-luc is highly sensitive and accurate method to track the fate of the parasite in the vector, in the crop, intestine and rectum. This methodology is useful to gain a better understanding of the parasite – insect vector interactions.

Henriques Cristina

2012-09-01

8

In vivo dual substrate bioluminescent imaging.  

Science.gov (United States)

Our understanding of how and when breast cancer cells transit from established primary tumors to metastatic sites has increased at an exceptional rate since the advent of in vivo bioluminescent imaging technologies. Indeed, the ability to locate and quantify tumor growth longitudinally in a single cohort of animals to completion of the study as opposed to sacrificing individual groups of animals at specific assay times has revolutionized how researchers investigate breast cancer metastasis. Unfortunately, current methodologies preclude the real-time assessment of critical changes that transpire in cell signaling systems as breast cancer cells (i) evolve within primary tumors, (ii) disseminate throughout the body, and (iii) reinitiate proliferative programs at sites of a metastatic lesion. However, recent advancements in bioluminescent imaging now make it possible to simultaneously quantify specific spatiotemporal changes in gene expression as a function of tumor development and metastatic progression via the use of dual substrate luminescence reactions. To do so, researchers take advantage for two light-producing luciferase enzymes isolated from the firefly (Photinus pyralis) and sea pansy (Renilla reniformis), both of which react to mutually exclusive substrates that previously facilitated their wide-spread use in in vitro cell-based reporter gene assays. Here we demonstrate the in vivo utility of these two enzymes such that one luminescence reaction specifically marks the size and location of a developing tumor, while the second luminescent reaction serves as a means to visualize the activation status of specific signaling systems during distinct stages of tumor and metastasis development. Thus, the objectives of this study are two-fold. First, we will describe the steps necessary to construct dual bioluminescent reporter cell lines, as well as those needed to facilitate their use in visualizing the spatiotemporal regulation of gene expression during specific steps of the metastatic cascade. Using the 4T1 model of breast cancer metastasis, we show that the in vivo activity of a synthetic Smad Binding Element (SBE) promoter was decreased dramatically in pulmonary metastasis as compared to that measured in the primary tumor. Recently, breast cancer metastasis was shown to be regulated by changes within the primary tumor microenvironment and reactive stroma, including those occurring in fibroblasts and infiltrating immune cells. Thus, our second objective will be to demonstrate the utility of dual bioluminescent techniques in monitoring the growth and localization of two unique cell populations harbored within a single animal during breast cancer growth and metastasis. PMID:22006228

Wendt, Michael K; Molter, Joseph; Flask, Christopher A; Schiemann, William P

2011-01-01

9

Dynamic bioluminescence imaging for quantitative tumour burden assessment using IV or IP administration of d-luciferin: effect on intensity, time kinetics and repeatability of photon emission  

International Nuclear Information System (INIS)

In vivo bioluminescence imaging (BLI) is a promising technique for non-invasive tumour imaging. d-luciferin can be administrated intraperitonealy or intravenously. This will influence its availability and, therefore, the bioluminescent signal. The aim of this study is to compare the repeatability of BLI measurement after IV versus IP administration of d-luciferin and assess the correlation between photon emission and histological cell count both in vitro and in vivo. Fluc-positive R1M cells were subcutaneously inoculated in nu/nu mice. Dynamic BLI was performed after IV or IP administration of d-luciferin. Maximal photon emission (PEmax) was calculated. For repeatability assessment, every acquisition was repeated after 4 h and analysed using Bland-Altman method. A second group of animals was serially imaged, alternating IV and IP administration up to 21 days. When mice were killed, PEmax after IV administration was correlated with histological cell number. The coefficients of repeatability were 80.2% (IV) versus 95.0% (IP). Time-to-peak is shorter, and its variance lower for IV (p max was 5.6 times higher for IV. A trend was observed towards lower photon emission per cell in larger tumours. IV administration offers better repeatability and better sensitivity when compared to IP. In larger tumours, multiple factors may contribute to underestimation of tumour burden. It might, therefore, be beneficial to test novel therapeutore, be beneficial to test novel therapeutics on small tumours to enable an accurate evaluation of tumour burden. (orig.)

10

Bioluminescence.  

Science.gov (United States)

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

Jones, M. Gail

1993-01-01

11

Bioluminescence tomography improves quantitative accuracy for pre-clinical imaging  

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A study is presented that demonstrates that bioluminescence tomography can reconstruct accurate 3D images of internal light sources placed at a range of depths within a physical phantom and that it provides more reliable quantitative data than standard bioluminescence imaging. Specifically, it is shown that when imaging sources at depths ranging from 5 to 15mm, estimates of total source strength are stable to within +/-11% using tomography whilst values deduced by traditional methods vary 10-fold. Additionally, the tomographic approach correctly localises sources to within 1.5mm error in all cases considered.

Guggenheim, James A.; Basevi, Hector R. A.; Styles, Iain B.; Frampton, Jon; Dehghani, Hamid

2013-06-01

12

Transport-theory-based stochastic image reconstruction of bioluminescent sources.  

Science.gov (United States)

A stochastic image reconstruction methodology is proposed for solving the highly ill-posed inverse bioluminescent source problem in light-scattering media. The unknown source distribution is expressed in terms of a set of linearly independent source basis functions. The bioluminescent boundary flux originating from each source basis function is computed prior to image reconstruction by solving the equation of radiative transfer. The misfit between the measured and the predicted boundary flux is described by an error function, which is iteratively minimized by stochastically sampling the global parameter space of all basis functions. Selection and alteration mechanisms, which can be guided by evolutionary principles found in nature, lead to new stochastic samples of source distributions for the next iteration cycle. A least-squares-error solution, representing the sought image of the unknown source distribution, is obtained after convergence. Numerical experiments demonstrate the feasibility of reconstructing bioluminescent source distributions in tissuelike media. PMID:17491627

Klose, Alexander D

2007-06-01

13

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

14

Hyperspectral and multispectral bioluminescence optical tomography for small animal imaging  

International Nuclear Information System (INIS)

ion of 1.5 to 2.2 mm for depths up to 6 mm can be achieved. We also include an in vivo study of a mouse with a brain tumour expressing firefly luciferase. Co-registration of the reconstructed 3D bioluminescent image with magnetic resonance images indicated good anatomical localization of the tumour

15

Space application research of EMCCDs for bioluminescence imaging  

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The detection of bioluminescense is widely used on the ground, while the detection of bioluminescence in space is still at the stage of detecting bright bioluminescense. With the rapid development of research in Space Life Sciences, it will be necessary to develop a detection technology to detect weak bioluminescense. Compared to other low-light detection techniques for ground, there are more advantages of EMCCDs for space application. Build a space bioluminescence imaging detection system, analysis the feasibility and capability of its will be significant. Co-Author:Xie Zongbao,Zheng Weibo

Zhang, Tao

16

Triple Bioluminescence Imaging for In Vivo Monitoring of Cellular Processes  

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Bioluminescence imaging (BLI) has shown to be crucial for monitoring in vivo biological processes. So far, only dual bioluminescence imaging using firefly (Fluc) and Renilla or Gaussia (Gluc) luciferase has been achieved due to the lack of availability of other efficiently expressed luciferases using different substrates. Here, we characterized a codon-optimized luciferase from Vargula hilgendorfii (Vluc) as a reporter for mammalian gene expression. We showed that Vluc can be multiplexed with Gluc and Fluc for sequential imaging of three distinct cellular phenomena in the same biological system using vargulin, coelenterazine, and D-luciferin substrates, respectively. We applied this triple imaging system to monitor the effect of soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) delivered using an adeno-associated viral vector (AAV) on brain tumors in mice. Vluc imaging showed efficient sTRAIL gene delivery to the brain, while Fluc imaging revealed a robust antiglioma therapy. Further, nuclear factor-?B (NF-?B) activation in response to sTRAIL binding to glioma cells death receptors was monitored by Gluc imaging. This work is the first demonstration of trimodal in vivo bioluminescence imaging and will have a broad applicability in many different fields including immunology, oncology, virology, and neuroscience. PMID:23778500

Maguire, Casey A; Bovenberg, M Sarah; Crommentuijn, Matheus HW; Niers, Johanna M; Kerami, Mariam; Teng, Jian; Sena-Esteves, Miguel; Badr, Christian E; Tannous, Bakhos A

2013-01-01

17

Development of Quantification Method for Bioluminescence Imaging  

Energy Technology Data Exchange (ETDEWEB)

Optical molecular luminescence imaging is widely used for detection and imaging of bio-photons emitted by luminescent luciferase activation. The measured photons in this method provide the degree of molecular alteration or cell numbers with the advantage of high signal-to-noise ratio. To extract useful information from the measured results, the analysis based on a proper quantification method is necessary. In this research, we propose a quantification method presenting linear response of measured light signal to measurement time. We detected the luminescence signal by using lab-made optical imaging equipment of animal light imaging system (ALIS) and different two kinds of light sources. One is three bacterial light-emitting sources containing different number of bacteria. The other is three different non-bacterial light sources emitting very weak light. By using the concept of the candela and the flux, we could derive simplified linear quantification formula. After experimentally measuring light intensity, the data was processed with the proposed quantification function. We could obtain linear response of photon counts to measurement time by applying the pre-determined quantification function. The ratio of the re-calculated photon counts and measurement time present a constant value although different light source was applied. The quantification function for linear response could be applicable to the standard quantification process. The proposed method could be used for the exact quantitative analysis in various light imaging equipment with presenting linear response behavior of constant light emitting sources to measurement time

Kim, Hyeon Sik; Min, Jung Joon; Lee, Byeong Il [Chonnam National University Hospital, Hwasun (Korea, Republic of); Choi, Eun Seo [Chosun University, Gwangju (Korea, Republic of); Tak, Yoon O; Choi, Heung Kook; Lee, Ju Young [Inje University, Kimhae (Korea, Republic of)

2009-10-15

18

In vivo fluorescence imaging of the reticuloendothelial system using quantum dots in combination with bioluminescent tumour monitoring  

Energy Technology Data Exchange (ETDEWEB)

We characterised in vivo fluorescence imaging (FLI) of the reticuloendothelial system using quantum dots (QD) and investigated its use in combination with in vivo bioluminescence imaging (BLI). In vivo FLI was performed in five mice repeatedly after the intravenous administration of QD without conjugation to targeting ligands. Ex vivo FLI of the excised organs was performed 24 h after QD injection in three mice. Seven days after intravenous inoculation of luciferase-expressing model cells of a haematological malignancy, mice were injected with the QD or saline (n = 5 each), and combined BLI/FLI was performed repeatedly. Additional five mice inoculated with the tumour cells were examined by in vivo BLI/FLI, and the structures harbouring bioluminescent foci were determined by ex vivo BLI. The utility of combining FLI with bioluminescent tumour monitoring was evaluated. In vivo FLI after QD injection allowed long-term, repeated observation of the reticuloendothelial system in individual mice, although fluorescence intensity and image contrast gradually decreased over time. Ex vivo FLI verified selective accumulation in reticuloendothelial structures. The administration of QD did not affect whole-body bioluminescent signal intensities during longitudinal tumour monitoring. In vivo BLI/FLI, accompanied by fusion of both images, improved the accuracy and confidence level of the localisation of the bioluminescent foci. In vivo FLI using QD provides an overview of the reticuloendothelial system in living mice. In combination with bioluminescent tumour monitoring, fluorescent reticuloendothelial imaging is expected to provide valuable information for lesion localisation. (orig.)

Inoue, Yusuke; Yamada, Haruyasu [University of Tokyo, Department of Radiology, Institute of Medical Science, Tokyo (Japan); Izawa, Kiyoko; Tojo, Arinobu [University of Tokyo, Division of Molecular Therapy, Advanced Clinical Research Centre, Institute of Medical Science, Tokyo (Japan); Yoshikawa, Kohki [Komazawa University, Department of Radiotechnical Sciences, Faculty of Radiological Health Sciences, Tokyo (Japan); Ohtomo, Kuni [University of Tokyo, Department of Radiology, Graduate School of Medicine, Tokyo (Japan)

2007-12-15

19

Filtering and deconvolution for bioluminescence imaging of small animals; Filtrage et deconvolution en imagerie de bioluminescence chez le petit animal  

Energy Technology Data Exchange (ETDEWEB)

This thesis is devoted to analysis of bioluminescence images applied to the small animal. This kind of imaging modality is used in cancerology studies. Nevertheless, some problems are related to the diffusion and the absorption of the tissues of the light of internal bioluminescent sources. In addition, system noise and the cosmic rays noise are present. This influences the quality of the images and makes it difficult to analyze. The purpose of this thesis is to overcome these disturbing effects. We first have proposed an image formation model for the bioluminescence images. The processing chain is constituted by a filtering stage followed by a deconvolution stage. We have proposed a new median filter to suppress the random value impulsive noise which corrupts the acquired images; this filter represents the first block of the proposed chain. For the deconvolution stage, we have performed a comparative study of various deconvolution algorithms. It allowed us to choose a blind deconvolution algorithm initialized with the estimated point spread function of the acquisition system. At first, we have validated our global approach by comparing our obtained results with the ground truth. Through various clinical tests, we have shown that the processing chain allows a significant improvement of the spatial resolution and a better distinction of very close tumor sources, what represents considerable contribution for the users of bioluminescence images. (author)

Akkoul, S.

2010-06-22

20

Assessing laser-tissue damage with bioluminescent imaging  

Science.gov (United States)

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

 
 
 
 
21

Noninvasive bioluminescence imaging of herpes simplex virus type 1 infection and therapy in living mice.  

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Mouse models of herpes simplex virus type 1 (HSV-1) infection provide significant insights into viral and host genes that regulate disease pathogenesis, but conventional methods to determine the full extent of viral spread and replication typically require the sacrifice of infected animals. To develop a noninvasive method for detecting HSV-1 in living mice, we used a strain KOS HSV-1 recombinant that expresses firefly (Photinus pyralis) and Renilla (Renilla reniformis) luciferase reporter proteins and monitored infection with a cooled charge-coupled device camera. Viral infection in mouse footpads, peritoneal cavity, brain, and eyes could be detected by bioluminescence imaging of firefly luciferase. The activity of Renilla luciferase could be imaged after direct administration of substrate to infected eyes but not following the systemic delivery of substrate. The magnitude of bioluminescence from firefly luciferase measured in vivo correlated directly with input titers of recombinant virus used for infection. Treatment of infected mice with valacyclovir, a potent inhibitor of HSV-1 replication, produced dose-dependent decreases in firefly luciferase activity that correlated with changes in viral titers. These data demonstrate that bioluminescence imaging can be used for noninvasive, real-time monitoring of HSV-1 infection and therapy in living mice. PMID:12414955

Luker, Gary D; Bardill, J Patrick; Prior, Julie L; Pica, Christina M; Piwnica-Worms, David; Leib, David A

2002-12-01

22

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

23

In vivo fluorescence imaging of the reticuloendothelial system using quantum dots in combination with bioluminescent tumour monitoring  

International Nuclear Information System (INIS)

We characterised in vivo fluorescence imaging (FLI) of the reticuloendothelial system using quantum dots (QD) and investigated its use in combination with in vivo bioluminescence imaging (BLI). In vivo FLI was performed in five mice repeatedly after the intravenous administration of QD without conjugation to targeting ligands. Ex vivo FLI of the excised organs was performed 24 h after QD injection in three mice. Seven days after intravenous inoculation of luciferase-expressing model cells of a haematological malignancy, mice were injected with the QD or saline (n = 5 each), and combined BLI/FLI was performed repeatedly. Additional five mice inoculated with the tumour cells were examined by in vivo BLI/FLI, and the structures harbouring bioluminescent foci were determined by ex vivo BLI. The utility of combining FLI with bioluminescent tumour monitoring was evaluated. In vivo FLI after QD injection allowed long-term, repeated observation of the reticuloendothelial system in individual mice, although fluorescence intensity and image contrast gradually decreased over time. Ex vivo FLI verified selective accumulation in reticuloendothelial structures. The administration of QD did not affect whole-body bioluminescent signal intensities during longitudinal tumour monitoring. In vivo BLI/FLI, accompanied by fusion of both images, improved the accuracy and confidence level of the localisation of the bioluminescent foci. In vivo FLI using QD provides an overview of the reticuling QD provides an overview of the reticuloendothelial system in living mice. In combination with bioluminescent tumour monitoring, fluorescent reticuloendothelial imaging is expected to provide valuable information for lesion localisation. (orig.)

24

Bioluminescence Imaging of Stem Cell-Based Therapeutics for Vascular Regeneration  

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Full Text Available Stem cell-based therapeutics show promise for treatment of vascular diseases. However, the survival of the cells after in vivo injection into diseased tissues remains a concern. In the advent of non-invasive optical imaging techniques such as bioluminescence imaging (BLI, cell localization and survival can be easily monitored over time. This approach has recently been applied towards monitoring stem cell treatments for vascular regeneration of the coronary or peripheral arteries. In this review, we will describe the application of BLI for tracking transplanted stem cells and associating their viability with therapeutic efficacy, in preclinical disease models of vascular disease.

Ngan F. Huang, Janet Okogbaa, Anna Babakhanyan, John P. Cooke

2012-01-01

25

Tomographic bioluminescence imaging by an iteratively re-weighted minimization  

Science.gov (United States)

Tomographic bioluminescence imaging (TBI), with visible light emission in living organisms, is an effective way of molecular imaging, which allows for the study of ongoing tumor biological processes in vivo and non-invasively. This newly developed technology enables three-dimensional accuracy localization and quantitative analysis of the target tumor cells in small animal via reconstructing the images acquired by the high-resolution imaging system. Due to the difficulty of reconstruction, which is often referred to an ill-posed inverse problem, continuous efforts are still made to find more practical and efficient approaches. In this paper, an iteratively re-weighted minimization (IRM) has been applied to reconstruct the entire source distribution, which is known as sparse signals, inside the target tissue with the limited outgoing photon density on its boundary. By introducing a weight function into the objective function, we convert the lp norm problem into a more simple form of l2 norm to reduce the computational complexity. The weight function is updated in each iterative step to compute the final optimal solution more efficiently. This method is proved to be robust to different parameters, and mouse experiments are conducted to validate the feasibility of IRM approach, which is also reliable at whole-body imaging.

Wu, Ping; Liu, Kai; Xue, Zhenwen; Guo, Wei; Qin, Chenghu; Tian, Jie

2012-03-01

26

Effect of optical tissue clearing on spatial resolution and sensitivity of bioluminescence imaging.  

Science.gov (United States)

In vivo bioluminescence imaging (BLI) is a powerful method of in vivo molecular imaging based on the use of optically active luciferase reporter genes. Although this method provides superior sensitivity relative to other in vivo imaging methods, spatial resolution is poor due to light scattering. The objective of this study was to use hyperosmotic agents to reduce the scattering coefficient and hence improve spatial resolution of the BLI method. A diffusing fiber tip was used to simulate an isotropic point source of bioluminescence emission (550 to 650 nm). Mouse skin was treated in vitro and in vivo with glycerol (50%, 30 min) and measurements of optical properties, and imaging photon counts were made before, during, and after application of glycerol to the skin sample. Glycerol application to mouse skin had little effect on the absorption coefficient but reduced the reduced scattering coefficient by more than one order of magnitude. This effect was reversible. Consequently, the spot size (i.e., spatial resolution) of the bioluminescence point source imaged through the skin decreased by a factor of 2 (550-nm light) to 3 (650-nm light) after 30 min. Simultaneously, an almost twofold decrease in the amount of light detected by the BLI system was observed, despite the fact that total transmission increased 1.7 times. We have shown here that multiply scattered light is responsible for both observations. We have shown that applying a hyperosmotic clearing agent to the skin of small rodents has the potential to improve spatial resolution of BLI owing to a reduction in the reduced scattering coefficient in the skin by one order of magnitude. However, reducing the scattering coefficient reduces the amount of light reaching the camera due to a reduction in the amount of multiply scattered light that reaches the camera aperture and thus reducing the sensitivity of the method. PMID:16965147

Jansen, E Duco; Pickett, Patrick M; Mackanos, Mark A; Virostko, John

2006-01-01

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

Science.gov (United States)

Background In vivo bioluminescence, fluorescence, and single-photon emission computed tomography (SPECT) imaging provide complementary information about biological processes. However, to date these signatures are evaluated separately on individual preclinical systems. In this paper, we introduce a fully integrated bioluminescence-fluorescence-SPECT platform. Next to an optimization in logistics and image fusion, this integration can help improve understanding of the optical imaging (OI) results. Methods An OI module was developed for a preclinical SPECT system (U-SPECT, MILabs, Utrecht, the Netherlands). The applicability of the module for bioluminescence and fluorescence imaging was evaluated in both a phantom and in an in vivo setting using mice implanted with a 4 T1-luc?+?tumor. A combination of a fluorescent dye and radioactive moiety was used to directly relate the optical images of the module to the SPECT findings. Bioluminescence imaging (BLI) was compared to the localization of the fluorescence signal in the tumors. Results Both the phantom and in vivo mouse studies showed that superficial fluorescence signals could be imaged accurately. The SPECT and bioluminescence images could be used to place the fluorescence findings in perspective, e.g. by showing tracer accumulation in non-target organs such as the liver and kidneys (SPECT) and giving a semi-quantitative read-out for tumor spread (bioluminescence). Conclusions We developed a fully integrated multimodal platform that provides complementary registered imaging of bioluminescent, fluorescent, and SPECT signatures in a single scanning session with a single dose of anesthesia. In our view, integration of these modalities helps to improve data interpretation of optical findings in relation to radionuclide images. PMID:25386389

2014-01-01

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Bioluminescence imaging of human embryonic stem cells transplanted in vivo in murine and chick models.  

Science.gov (United States)

Research into the behavior, efficacy, and biosafety of stem cells with a view to clinical transplantation requires the development of noninvasive methods for in vivo imaging of cells transplanted into animal models. This is particularly relevant for human embryonic stem cells (hESCs), because transplantation of undifferentiated hESCs leads to tumor formation. The present study aimed to monitor hESCs in real time when injected in vivo. hESCs were stably transfected to express luciferase, and luciferase expression was clearly detected in the undifferentiated and differentiated state. When transfected hESCs were injected into chick embryos, bioluminescence could be detected both ex and in ovo. In the SCID mouse model, undifferentiated hESCs were detectable after injection either into the muscle layer of the peritoneum or the kidney capsule. Tumors became detectable between days 10-30, with approximately a 3 log increase in the luminescence signal by day 75. The growth phase occurred earlier in the kidney capsule and then reached a plateau, whilst tumors in the peritoneal wall grew steadily throughout the period analysed. These results show the widespread utility of bioluminescent for in vivo imaging of hESCs in a variety of model systems for preclinical research into regenerative medicine and cancer biology. PMID:19522673

Priddle, Helen; Grabowska, Anna; Morris, Teresa; Clarke, Philip A; McKenzie, Andrew J; Sottile, Virginie; Denning, Chris; Young, Lorraine; Watson, Sue

2009-06-01

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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  

Directory of Open Access Journals (Sweden)

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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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

31

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

Science.gov (United States)

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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Evaluation of biolistic gene transfer methods in vivo using non-invasive bioluminescent imaging techniques  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Gene therapy continues to hold great potential for treating many different types of disease and dysfunction. Safe and efficient techniques for gene transfer and expression in vivo are needed to enable gene therapeutic strategies to be effective in patients. Currently, the most commonly used methods employ replication-defective viral vectors for gene transfer, while physical gene transfer methods such as biolistic-mediated ("gene-gun" delivery to target tissues have not been as extensively explored. In the present study, we evaluated the efficacy of biolistic gene transfer techniques in vivo using non-invasive bioluminescent imaging (BLI methods. Results Plasmid DNA carrying the firefly luciferase (LUC reporter gene under the control of the human Cytomegalovirus (CMV promoter/enhancer was transfected into mouse skin and liver using biolistic methods. The plasmids were coupled to gold microspheres (1 ?m diameter using different DNA Loading Ratios (DLRs, and "shot" into target tissues using a helium-driven gene gun. The optimal DLR was found to be in the range of 4-10. Bioluminescence was measured using an In Vivo Imaging System (IVIS-50 at various time-points following transfer. Biolistic gene transfer to mouse skin produced peak reporter gene expression one day after transfer. Expression remained detectable through four days, but declined to undetectable levels by six days following gene transfer. Maximum depth of tissue penetration following biolistic transfer to abdominal skin was 200-300 ?m. Similarly, biolistic gene transfer to mouse liver in vivo also produced peak early expression followed by a decline over time. In contrast to skin, however, liver expression of the reporter gene was relatively stable 4-8 days post-biolistic gene transfer, and remained detectable for nearly two weeks. Conclusions The use of bioluminescence imaging techniques enabled efficient evaluation of reporter gene expression in vivo. Our results demonstrate that different tissues show different expression kinetics following gene transfer of the same reporter plasmid to different mouse tissues in vivo. We evaluated superficial (skin and abdominal organ (liver targets, and found that reporter gene expression peaked within the first two days post-transfer in each case, but declined most rapidly in the skin (3-4 days compared to liver (10-14 days. This information is essential for designing effective gene therapy strategies in different target tissues.

Daniell Henry

2011-06-01

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Bioluminescence imaging to monitor the prolongation of stem cell survival by pharmaceutical intervention  

Energy Technology Data Exchange (ETDEWEB)

The rapid donor cell death and rejection owing to humoral and cellular immune reactions are a basic limitation encountered in stem cell therapy for treatment of cardiovascular disease. We investigated the potential for longitudinal bioluminescence imaging to monitor the survival of transplanted stem cells prolonged by immunosuppressive agents. Embryonic rat H9c2 cardio myoblasts were transfected with adenovirus containing luciferase reporter gene (Ad-CMV-Fluc) in different MOI (1,10,100) and various cell doses (1x10{sup 5} - 5x10{sup 6})followed by injection in the thigh muscle of nude mice (n=6 per group), Other mice (n = 18) were undergone transient immunosuppression provided by either Cyclosporine (5mg/kg) or Tacrolimus (1mg/kg) or Dexamethasone (4mg/kg) beginning 3 days prior to and continuing to 2 weeks after transplantation. Optical bioluminescent imaging was then daily carried out using cooled CCD camera (Xenogen) Viral transfection at MOI 100 and the 5x10{sup 6} cell dose implantation resulted in optimal transgene efficiency. Mice received immunosuppressive agents displayed long-term in vivo reporter gene expression for a time course of 14 days. Tacrolimus (Prograf) and Cyclosporine successfully suppressed the transplanted cell loss in animals, that obviously observed until day 8 as compared to Dexamethasone-treated and non-treated mice (day 1: 1.00E+08 (Prograf), 9.47E+07 (Cys), 5.25E+07 (Dex), and 1.25E+07 p/s/cm{sup 2}/sr (control); day 8: 3.27E+05 (Prograf), 1.02E+05 (Cys), 6.17E+04 (Dex) and 2.73E+04 p/s/cm{sup 2}/sr (control)) and continued expressing bioluminescence until day 13 ( 6.42E+05 (Prograf), 4.99E+05 (Cys), and 4.10E+04 p/s/cm{sup 2}/sr. Induction of immune tolerance using pharmaceutical agents during cardio myoblast transplantation improved long-term donor cell survival in murine muscles. Optical imaging technique is capable of being used for tracking implanted stem cells in myocardium of living subjects over time.

Le, Uyenchi N.; Min, Jung Joon; Moon, Sung Min; Ahn, Young Keun; Kim, Yong Sook; Joo, Soo Yeon; Hong, Moon Hwa; Jeong, Myung Ho; Song, Ho Cheon; Bom, Hee Seung [Chonnam National University Medical School, Gwangju (Korea, Republic of)

2005-07-01

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Development of Optical Molecular Imaging System for the Acquisition of Bioluminescence Signals from Small Animals  

International Nuclear Information System (INIS)

Optical imaging is providing great advance and improvement in genetic and molecular imaging of animals and humans. Optical imaging system consists of optical imaging devices, which carry out major function for monitoring, tracing, and imaging in most of molecular in-vivo researches. In bio-luminescent imaging, small animals containing luciferase gene locally irradiate light, and emitted photons transmitted through skin of the small animals are imaged by using a high sensitive charged coupled device (CCD) camera. In this paper, we introduced optical imaging system for the image acquisition of bio-luminescent signals emitted from small animals. In the system, Nikon lens and four LED light sources were mounted at the inside of a dark box. A cooled CCD camera equipped with a control module was used. We tested the performance of the optical imaging system using effendorf tube and light emitting bacteria which injected intravenously into CT26 tumor bearing nude mouse. The performance of implemented optical imaging system for bio-luminescence imaging was demonstrated and the feasibility of the system in small animal imaging application was proved. We anticipate this system could be a useful tool for the molecular imaging of small animals adaptable for various experimental conditions in future

35

Development of Optical Molecular Imaging System for the Acquisition of Bioluminescence Signals from Small Animals  

Energy Technology Data Exchange (ETDEWEB)

Optical imaging is providing great advance and improvement in genetic and molecular imaging of animals and humans. Optical imaging system consists of optical imaging devices, which carry out major function for monitoring, tracing, and imaging in most of molecular in-vivo researches. In bio-luminescent imaging, small animals containing luciferase gene locally irradiate light, and emitted photons transmitted through skin of the small animals are imaged by using a high sensitive charged coupled device (CCD) camera. In this paper, we introduced optical imaging system for the image acquisition of bio-luminescent signals emitted from small animals. In the system, Nikon lens and four LED light sources were mounted at the inside of a dark box. A cooled CCD camera equipped with a control module was used. We tested the performance of the optical imaging system using effendorf tube and light emitting bacteria which injected intravenously into CT26 tumor bearing nude mouse. The performance of implemented optical imaging system for bio-luminescence imaging was demonstrated and the feasibility of the system in small animal imaging application was proved. We anticipate this system could be a useful tool for the molecular imaging of small animals adaptable for various experimental conditions in future

Lee, Byeong Il; Kim, Hyeon Sik; Jeong, Hye Jin; Lee, Hyung Jae; Moon, Seung Min; Kwon, Seung Young; Jeong, Shin Young; Bom, Hee Seung; Min, Jung Joon [Chonnam National University Hospital, Gwangju (Korea, Republic of); Choi, Eun Seo [Chosun University, Gwangju (Korea, Republic of)

2009-08-15

36

Bioluminescence imaging to monitor the prolongation of stem cell survival by pharmaceutical intervention  

International Nuclear Information System (INIS)

E+07 p/s/cm2/sr (control); day 8: 3.27E+05 (Prograf), 1.02E+05 (Cys), 6.17E+04 (Dex) and 2.73E+04 p/s/cm2/sr (control)) and continued expressing bioluminescence until day 13 ( 6.42E+05 (Prograf), 4.99E+05 (Cys), and 4.10E+04 p/s/cm2/sr. Induction of immune tolerance using pharmaceutical agents during cardio myoblast transplantation improved long-term donor cell survival in murine muscles. Optical imaging technique is capable of being used for tracking implanted stem cells in myocardium of living subjects over time

37

Novel registration for microcomputed tomography and bioluminescence imaging based on iterated optimal projection  

Science.gov (United States)

As a high-sensitivity imaging modality, bioluminescence tomography can reconstruct the three-dimensional (3-D) location of an internal luminescent source based on the 3-D surface light distribution. However, we can only get the multi-orientation two-dimensional (2-D) bioluminescence distribution in the experiments. Therefore, developing an accurate universal registration method is essential for following bioluminescent source reconstruction. We can then map the multi-orientation 2-D bioluminescence distribution to the 3-D surface derived from anatomical information with it. We propose a 2-D -to-3-D registration method based on iterated optimal projection and applied it in a registration and reconstruction study of three transgenic mice. Compared with traditional registration methods based on the fixed points, our method was independent of the markers and the registration accuracy of the three experiments was improved by 0.3, 0.5, and 0.4 pixels, respectively. In addition, based on the above two registration results using the two registration methods, we reconstructed the 3-D location of the inner bioluminescent source in the three transgenic mice. The reconstruction results showed that the average error distance between the center of the reconstructed element and the center of the real element were reduced by 0.32, 0.48, and 0.39 mm, respectively.

Ma, Xibo; Deng, Kexin; Xue, Zhenwen; Liu, Xueyan; Zhu, Shouping; Qin, Chenghu; Yang, Xin; Tian, Jie

2013-02-01

38

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

International Nuclear Information System (INIS)

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

39

Extension of the GATE Monte-Carlo simulation package to model bioluminescence and fluorescence imaging.  

Science.gov (United States)

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 the GATE to support simulations of optical imaging, such as bioluminescence or fluorescence imaging, and validate it against the MC for multilayered media standard simulation tool for biomedical optics in simple geometries. A full simulation set-up for molecular optical imaging (bioluminescence and fluorescence) is implemented in GATE, and images of the light distribution emitted from a phantom demonstrate the relevance of using GATE for optical imaging simulations. PMID:24522804

Cuplov, Vesna; Buvat, Iréne; Pain, Frédéric; Jan, Sébastien

2014-02-01

40

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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Dual-color bioluminescence imaging assay using green- and red-emitting beetle luciferases at subcellular resolution.  

Science.gov (United States)

Bioluminescence imaging is widely used to monitor cellular events, including gene expression in vivo and in vitro. Moreover, recent advances in luciferase technology have made possible imaging at the single-cell level. To improve the bioluminescence imaging system, we have developed a dual-color imaging system in which the green-emitting luciferase from a Brazilian click beetle (Emerald Luc, ELuc) and the red-emitting luciferase from a railroad worm (Stable Luciferase Red, SLR) were used as reporters, which were localized to the peroxisome and the nucleus, respectively. We clearly captured simultaneously the subcellular localization of ELuc in the peroxisome and SLR in the nucleus of a single cell using a high-magnification objective lens with 3-min exposure time without binning using a combination of optical filters. Furthermore, to apply this system to quantitative time-lapse imaging, the activation of nuclear factor triggered by tumor necrosis factor ? was measured using nuclear-targeted SLR and peroxisome-targeted ELuc as the test and internal control reporters, respectively. We successfully quantified the kinetics of activation of nuclear factor ?B using nuclear-targeted SLR and the transcriptional change of the internal control promoter using peroxisome-targeted ELuc simultaneously in a single cell, and showed that the activation kinetics, including activation rate and amplitude, differed among cells. The results demonstrated that this imaging system can visualize the subcellular localization of reporters and track the expressions of two genes simultaneously at subcellular resolution. PMID:25015042

Yasunaga, Mayu; Nakajima, Yoshihiro; Ohmiya, Yoshihiro

2014-09-01

42

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

43

Beyond D-luciferin: expanding the scope of bioluminescence imaging in vivo.  

Science.gov (United States)

The light-emitting chemical reaction catalyzed by the enzyme firefly luciferase is widely used for noninvasive imaging in live mice. However, photon emission from the luciferase is crucially dependent on the chemical properties of its substrate, D-luciferin. In this review, we describe recent work to replace the natural luciferase substrate with synthetic analogs that extend the scope of bioluminescence imaging. PMID:25078002

Adams, Spencer T; Miller, Stephen C

2014-08-01

44

Gold-nanocrystal-enhanced bioluminescent nanocapsules.  

Science.gov (United States)

Metal-enhanced bioluminescence presents a great opportunity to achieve ultrasensitive analysis and imaging with low bioluminescent background and enhanced luminescence. We hereby report metal-enhanced bioluminescence based on bioluminescent protein nanocapsules conjugated with gold nanocrystals. Such gold-nanocapsule complexes exhibit near 10-fold enhancement in bioluminescent intensity and are effectively delivered into the cells with outstanding stability. This work offers a class of bioluminescent nanoparticles for imaging and other applications. PMID:25243486

Du, Juanjuan; Jin, Jing; Liu, Yang; Li, Jie; Tokatlian, Talar; Lu, Zuhong; Segura, Tatiana; Yuan, Xu-Bo; Yang, Xianjin; Lu, Yunfeng

2014-10-28

45

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

46

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

47

Efficacy assessment of sustained intraperitoneal paclitaxel therapy in a murine model of ovarian cancer using bioluminescent imaging  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We evaluated the pre-clinical efficacy of a novel intraperitoneal (i.p.) sustained-release paclitaxel formulation (PTXePC) using bioluminescent imaging (BLI) in the treatment of ovarian cancer. Human ovarian carcinoma cells stably expressing the firefly luciferase gene (SKOV3Luc) were injected i.p. into SCID mice. Tumour growth was evaluated during sustained or intermittent courses of i.p. treatment with paclitaxel (PTX). In vitro bioluminescence strongly correlated with cell survival and cyt...

Vassileva, V.; Moriyama, E. H.; Souza, R.; Grant, J.; Allen, C. J.; Wilson, B. C.; Piquette-miller, M.

2008-01-01

48

Investigating real-time activation of adenosine receptors by bioluminescence resonance energy transfer technique  

Science.gov (United States)

Adenosine receptors play important roles in many physiological and pathological processes, for example regulating myocardial oxygen consumption and the release of neurotransmitters. The activations of adenosine receptors have been studied by some kinds of techniques, such as western blot, immunohistochemistry, etc. However, these techniques cannot reveal the dynamical response of adenosine receptors under stimulation. In this paper, bioluminescence resonance energy transfer technique was introduced to study the real-time activation of adenosine receptors by monitoring the dynamics of cyclic adenosine monophosphate (cAMP) level. The results showed that there were significant differences between adenosine receptors on real-time responses under stimulation. Moreover, the dynamics of cAMP level demonstrated that competition between adenosine receptors existed. Taken together, our study indicates that monitoring the dynamics of cAMP level using bioluminescence resonance energy transfer technique could be one potential approach to investigate the mechanism of competitions between adenosine receptors.

Huang, Yimei; Yang, Hongqin; Zheng, Liqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen

2013-02-01

49

Detection and Quantitation of Circulating Tumor Cell Dynamics by Bioluminescence Imaging in an Orthotopic Mammary Carcinoma Model  

Science.gov (United States)

Circulating tumor cells (CTCs) have been detected in the bloodstream of both early-stage and advanced cancer patients. However, very little is know about the dynamics of CTCs during cancer progression and the clinical relevance of longitudinal CTC enumeration. To address this, we developed a simple bioluminescence imaging assay to detect CTCs in mouse models of metastasis. In a 4T1 orthotopic metastatic mammary carcinoma mouse model, we demonstrated that this quantitative method offers sensitivity down to 2 CTCs in 0.1–1mL blood samples and high specificity for CTCs originating from the primary tumor, independently of their epithelial status. In this model, we simultaneously monitored blood CTC dynamics, primary tumor growth, and lung metastasis progression over the course of 24 days. Early in tumor development, we observed low numbers of CTCs in blood samples (10–15 cells/100 µL) and demonstrated that CTC dynamics correlate with viable primary tumor growth. To our knowledge, these data represent the first reported use of bioluminescence imaging to detect CTCs and quantify their dynamics in any cancer mouse model. This new assay is opening the door to the study of CTC dynamics in a variety of animal models. These studies may inform clinical decision on the appropriate timing of blood sampling and value of longitudinal CTC enumeration in cancer patients. PMID:25188396

Sasportas, Laura Sarah; Hori, Sharon Seiko; Pratx, Guillem; Gambhir, Sanjiv Sam

2014-01-01

50

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

51

Validation of luminescent source reconstruction using spectrally resolved bioluminescence images  

Science.gov (United States)

This study examines the accuracy of the Living Image® Software 3D Analysis Package (Xenogen, Alameda, CA) in reconstruction of light source depth and intensity. Constant intensity light sources were placed in an optically homogeneous medium (chicken breast). Spectrally filtered images were taken at 560, 580, 600, 620, 640, and 660 nanometers. The Living Image® Software 3D Analysis Package was employed to reconstruct source depth and intensity using these spectrally filtered images. For sources shallower than the mean free path of light there was proportionally higher inaccuracy in reconstruction. For sources deeper than the mean free path, the average error in depth and intensity reconstruction was less than 4% and 12%, respectively. The ability to distinguish multiple sources decreased with increasing source depth and typically required a spatial separation of twice the depth. The constant intensity light sources were also implanted in mice to examine the effect of optical inhomogeneity. The reconstruction accuracy suffered in inhomogeneous tissue with accuracy influenced by the choice of optical properties used in reconstruction.

Virostko, John M.; Powers, Alvin C.; Jansen, E. D.

2008-02-01

52

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

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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

53

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

54

Registration of planar bioluminescence to magnetic resonance and x-ray computed tomography images as a platform for the development of bioluminescence tomography reconstruction algorithms  

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The procedures we propose make possible the mapping of two-dimensional (2-D) bioluminescence image (BLI) data onto a skin surface derived from a three-dimensional (3-D) anatomical modality [magnetic resonance (MR) or computed tomography (CT)] dataset. This mapping allows anatomical information to be incorporated into bioluminescence tomography (BLT) reconstruction procedures and, when applied using sources visible to both optical and anatomical modalities, can be used to evaluate the accuracy of those reconstructions. Our procedures, based on immobilization of the animal and a priori determined fixed projective transforms, should be more robust and accurate than previously described efforts, which rely on a poorly constrained retrospectively determined warping of the 3-D anatomical information. Experiments conducted to measure the accuracy of the proposed registration procedure found it to have a mean error of 0.36+/-0.23 mm. Additional experiments highlight some of the confounds that are often overlooked in the BLT reconstruction process, and for two of these confounds, simple corrections are proposed.

Beattie, Bradley J.; Klose, Alexander D.; Le, Carl H.; Longo, Valerie A.; Dobrenkov, Konstantine; Vider, Jelena; Koutcher, Jason A.; Blasberg, Ronald G.

2009-03-01

55

Accuracy of off-line bioluminescence imaging to localize targets in preclinical radiation research.  

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In this study, we investigated the accuracy of using off-line bioluminescence imaging (BLI) and tomography (BLT) to guide irradiation of small soft tissue targets on a small animal radiation research platform (SARRP) with on-board cone beam CT (CBCT) capability. A small glass bulb containing BL cells was implanted as a BL source in the abdomen of 11 mouse carcasses. Bioluminescence imaging and tomography were acquired for each carcass. Six carcasses were setup visually without immobilization and 5 were restrained in position with tape. All carcasses were setup in treatment position on the SARRP where the centroid position of the bulb on CBCT was taken as "truth". In the 2D visual setup, the carcass was setup by aligning the point of brightest luminescence with the vertical beam axis. In the CBCT assisted setup, the pose of the carcass on CBCT was aligned with that on the 2D BL image for setup. For both 2D setup methods, the offset of the bulb centroid on CBCT from the vertical beam axis was measured. In the BLT-CBCT fusion method, the 3D torso on BLT and CBCT was registered and the 3D offset of the respective source centroids was calculated. The setup results were independent of the carcass being immobilized or not due to the onset of rigor mortis. The 2D offset of the perceived BL source position from the CBCT bulb position was 2.3 mm ± 1.3 mm. The 3D offset between BLT and CBCT was 1.5 mm ± 0.9 mm. Given the rigidity of the carcasses, the setup results represent the best that can be achieved with off-line 2D BLI and 3D BLT. The setup uncertainty would require the use of undesirably large margin of 4-5 mm. The results compel the implementation of on-board BLT capability on the SARRP to eliminate setup error and to improve BLT accuracy. PMID:23578189

Tuli, Richard; Armour, Michael; Surmak, Andrew; Reyes, Juvenal; Iordachita, Iulian; Patterson, Michael; Wong, John

2013-04-01

56

The Bioluminescence Web Page  

Science.gov (United States)

Bioluminescence is "simply light produced by a chemical reaction which originates in an organism." This Web sitefrom the University of California at Santa Barbara intends to provide a reliable source of information on this somewhat obscure subject. The site contains a lot of basic information about the chemistry of bioluminescence and specific bioluminescent organisms, along with some fabulous images. More specific information can be obtained through research abstracts and citations posted in the Research Forum and recently added workshop section. This is an attractive site that will appeal to a wide variety of audiences.

2002-01-01

57

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

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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

2011-01-01

58

Metabolic imaging in microregions of tumors and normal tissues with bioluminescence and photon counting  

International Nuclear Information System (INIS)

A method has been developed for metabolic imaging on a microscopic level in tumors, tumor spheroids, and normal tissues. The technique makes it possible to determine the spatial distribution of glucose, lactate, and ATP in absolute terms at similar locations within tissues or cell aggregates. The substrate distributions are registered in serial cryostat sections from tissue cryobiopsies or from frozen spheroids with the use of bioluminescence reactions. The light emission is measured directly by a special imaging photon counting system enabling on-line image analysis. The technique has been applied to human breast cancer xenografts, to spheroids originating from a human colon adenocarcinoma, and to skeletal rat muscle. Preliminary data obtained indicate that heterogeneities in the substrate distributions measured are much more pronounced in tumors than in normal tissue. There was no obvious correlation among the three quantities measured at similar locations within the tissues. The distribution of ATP corresponded well with the histological structure of larger spheroids; values were low in the necrotic center and high in the viable rim of these cell aggregates

59

Physicochemical characterization and in vivo bioluminescence imaging of nanostructured lipid carriers for targeting the brain: apomorphine as a model drug  

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Nanostructured lipid carriers (NLCs) were prepared to investigate whether the duration of brain targeting and accumulation of drugs in the brain can be improved by intravenous delivery. NLCs were developed using cetyl palmitate as the lipid matrix, squalene as the cationic surfactant, and Pluronic F68, polysorbate 80 and polyethylene glycol as the interfacial additives. Solid lipid nanoparticles (SLNs) and lipid emulsions (LEs) were also prepared for comparison. An anti-Parkinson's drug, apomorphine, was used as the model drug. Nuclear magnetic resonance and differential scanning calorimetry showed possible interactions between the solid and liquid lipids in the inner core. The lipid nanoparticles with different compositions were characterized by mean size, zeta potential, apomorphine encapsulation and in vitro drug release. NLCs were 370-430 nm in size, which was between the sizes of the SLNs and LEs. A cationic surfactant was used to produce a positive surface charge of 42-50 mV. The base form of apomorphine was successfully entrapped by NLCs with an entrapment percentage of > 60%. The loading of apomorphine in nanoparticles resulted in a slower release behavior compared to the aqueous solution, with LEs showing the lowest release. In vivo real-time bioluminescence imaging of the rat brain revealed that NLCs could be targeted, through certain vessels, to selected brain regions. This effect was further confirmed by imaging the entire brain and brain slices. The results indicated that NLCs with moderate additives are a promising controlled-release and drug-targeting system.

Hsu, Shu-Hui; Wen, Chih-Jen; Al-Suwayeh, S. A.; Chang, Hui-Wen; Yen, Tzu-Chen; Fang, Jia-You

2010-10-01

60

Physicochemical characterization and in vivo bioluminescence imaging of nanostructured lipid carriers for targeting the brain: apomorphine as a model drug  

Energy Technology Data Exchange (ETDEWEB)

Nanostructured lipid carriers (NLCs) were prepared to investigate whether the duration of brain targeting and accumulation of drugs in the brain can be improved by intravenous delivery. NLCs were developed using cetyl palmitate as the lipid matrix, squalene as the cationic surfactant, and Pluronic F68, polysorbate 80 and polyethylene glycol as the interfacial additives. Solid lipid nanoparticles (SLNs) and lipid emulsions (LEs) were also prepared for comparison. An anti-Parkinson's drug, apomorphine, was used as the model drug. Nuclear magnetic resonance and differential scanning calorimetry showed possible interactions between the solid and liquid lipids in the inner core. The lipid nanoparticles with different compositions were characterized by mean size, zeta potential, apomorphine encapsulation and in vitro drug release. NLCs were 370-430 nm in size, which was between the sizes of the SLNs and LEs. A cationic surfactant was used to produce a positive surface charge of 42-50 mV. The base form of apomorphine was successfully entrapped by NLCs with an entrapment percentage of > 60%. The loading of apomorphine in nanoparticles resulted in a slower release behavior compared to the aqueous solution, with LEs showing the lowest release. In vivo real-time bioluminescence imaging of the rat brain revealed that NLCs could be targeted, through certain vessels, to selected brain regions. This effect was further confirmed by imaging the entire brain and brain slices. The results indicated that NLCs with moderate additives are a promising controlled-release and drug-targeting system.

Hsu, Shu-Hui [Department of Pharmacy, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Wen, Chih-Jen; Yen, Tzu-Chen [Animal Molecular Imaging Center, Chang Gung Memorial Hospital, Kweishan, Taoyuan 333, Taiwan (China); Al-Suwayeh, S A; Fang, Jia-You [Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh (Saudi Arabia); Chang, Hui-Wen, E-mail: fajy@mail.cgu.edu.tw [Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, Kweishan, Taoyuan 333, Taiwan (China)

2010-10-08

 
 
 
 
61

Development of bioluminescent Salmonella strains for use in food safety  

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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

62

Development of a Novel Preclinical Pancreatic Cancer Research Model: Bioluminescence Image-Guided Focal Irradiation and Tumor Monitoring of Orthotopic Xenografts1  

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PURPOSE: We report on a novel preclinical pancreatic cancer research model that uses bioluminescence imaging (BLI)-guided irradiation of orthotopic xenograft tumors, sparing of surrounding normal tissues, and quantitative, noninvasive longitudinal assessment of treatment response. MATERIALS AND METHODS: Luciferase-expressing MiaPaCa-2 pancreatic carcinoma cells were orthotopically injected in nude mice. BLI was compared to pathologic tumor volume, and photon emission was assessed over time. BLI was correlated to positron emission tomography (PET)/computed tomography (CT) to estimate tumor dimensions. BLI and cone-beam CT (CBCT) were used to compare tumor centroid location and estimate setup error. BLI and CBCT fusion was performed to guide irradiation of tumors using the small animal radiation research platform (SARRP). DNA damage was assessed by ?-H2Ax staining. BLI was used to longitudinally monitor treatment response. RESULTS: Bioluminescence predicted tumor volume (R = 0.8984) and increased linearly as a function of time up to a 10-fold increase in tumor burden. BLI correlated with PET/CT and necropsy specimen in size (P < .05). Two-dimensional BLI centroid accuracy was 3.5 mm relative to CBCT. BLI-guided irradiated pancreatic tumors stained positively for ?-H2Ax, whereas surrounding normal tissues were spared. Longitudinal assessment of irradiated tumors with BLI revealed significant tumor growth delay of 20 days relative to controls. CONCLUSIONS: We have successfully applied the SARRP to a bioluminescent, orthotopic preclinical pancreas cancer model to noninvasively: 1) allow the identification of tumor burden before therapy, 2) facilitate image-guided focal radiation therapy, and 3) allow normalization of tumor burden and longitudinal assessment of treatment response. PMID:22496923

Tuli, Richard; Surmak, Andrew; Reyes, Juvenal; Hacker-Prietz, Amy; Armour, Michael; Leubner, Ashley; Blackford, Amanda; Tryggestad, Erik; Jaffee, Elizabeth M; Wong, John; DeWeese, Theodore L; Herman, Joseph M

2012-01-01

63

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

64

Rat model of metastatic breast cancer monitored by MRI at 3 tesla and bioluminescence imaging with histological correlation  

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Full Text Available Abstract Background Establishing a large rodent model of brain metastasis that can be monitored using clinically relevant magnetic resonance imaging (MRI techniques is challenging. Non-invasive imaging of brain metastasis in mice usually requires high field strength MR units and long imaging acquisition times. Using the brain seeking MDA-MB-231BR transfected with luciferase gene, a metastatic breast cancer brain tumor model was investigated in the nude rat. Serial MRI and bioluminescence imaging (BLI was performed and findings were correlated with histology. Results demonstrated the utility of multimodality imaging in identifying unexpected sights of metastasis and monitoring the progression of disease in the nude rat. Methods Brain seeking breast cancer cells MDA-MB-231BR transfected with firefly luciferase (231BRL were labeled with ferumoxides-protamine sulfate (FEPro and 1-3 × 106 cells were intracardiac (IC injected. MRI and BLI were performed up to 4 weeks to monitor the early breast cancer cell infiltration into the brain and formation of metastases. Rats were euthanized at different time points and the imaging findings were correlated with histological analysis to validate the presence of metastases in tissues. Results Early metastasis of the FEPro labeled 231BRL were demonstrated onT2*-weighted MRI and BLI within 1 week post IC injection of cells. Micro-metastatic tumors were detected in the brain on T2-weighted MRI as early as 2 weeks post-injection in greater than 85% of rats. Unexpected skeletal metastases from the 231BRL cells were demonstrated and validated by multimodal imaging. Brain metastases were clearly visible on T2 weighted MRI by 3-4 weeks post infusion of 231BRL cells, however BLI did not demonstrate photon flux activity originating from the brain in all animals due to scattering of the photons from tumors. Conclusion A model of metastatic breast cancer in the nude rat was successfully developed and evaluated using multimodal imaging including MRI and BLI providing the ability to study the temporal and spatial distribution of metastases in the brain and skeleton.

Klaunberg Brenda

2009-10-01

65

Novel mouse mammary cell lines for in vivo bioluminescence imaging (BLI of bone metastasis  

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Full Text Available Abstract Background Tumor cell lines that can be tracked in vivo during tumorigenesis and metastasis provide vital tools for studying the specific cellular mechanisms that mediate these processes as well as investigating therapeutic targets to inhibit them. The goal of this study was to engineer imageable mouse mammary tumor cell lines with discrete propensities to metastasize to bone in vivo. Two novel luciferase expressing cell lines were developed and characterized for use in the study of breast cancer metastasis to bone in a syngeneic mouse model. Results The 4 T1.2 luc3 and 66c14 luc2 cell lines were shown to have high levels of bioluminescence intensity in vitro and in vivo after orthotopic injection into mouse mammary fat pads. The 4 T1.2 luc3 cell line was found to closely model the sites of metastases seen in human patients including lung, liver, and bone. Specifically, 4 T1.2 luc3 cells demonstrated a high incidence of metastasis to spine, with an ex-vivo BLI intensity three orders of magnitude above the commercially available 4 T1 luc2 cells. 66c14 luc2 cells also demonstrated metastasis to spine, which was lower than that of 4 T1.2 luc3 cells but higher than 4 T1 luc2 cells, in addition to previously unreported metastases in the liver. High osteolytic activity of the 4 T1.2 luc3 cells in vivo in the bone microenvironment was also detected. Conclusions The engineered 4 T1.2 luc3 and 66c14 luc2 cell lines described in this study are valuable tools for studying the cellular events moderating the metastasis of breast tumor cells to bone.

Bolin Celeste

2012-04-01

66

Physicochemical characterization and in vivo bioluminescence imaging of nanostructured lipid carriers for targeting the brain: apomorphine as a model drug  

International Nuclear Information System (INIS)

Nanostructured lipid carriers (NLCs) were prepared to investigate whether the duration of brain targeting and accumulation of drugs in the brain can be improved by intravenous delivery. NLCs were developed using cetyl palmitate as the lipid matrix, squalene as the cationic surfactant, and Pluronic F68, polysorbate 80 and polyethylene glycol as the interfacial additives. Solid lipid nanoparticles (SLNs) and lipid emulsions (LEs) were also prepared for comparison. An anti-Parkinson's drug, apomorphine, was used as the model drug. Nuclear magnetic resonance and differential scanning calorimetry showed possible interactions between the solid and liquid lipids in the inner core. The lipid nanoparticles with different compositions were characterized by mean size, zeta potential, apomorphine encapsulation and in vitro drug release. NLCs were 370-430 nm in size, which was between the sizes of the SLNs and LEs. A cationic surfactant was used to produce a positive surface charge of 42-50 mV. The base form of apomorphine was successfully entrapped by NLCs with an entrapment percentage of > 60%. The loading of apomorphine in nanoparticles resulted in a slower release behavior compared to the aqueous solution, with LEs showing the lowest release. In vivo real-time bioluminescence imaging of the rat brain revealed that NLCs could be targeted, through certain vessels, to selected brain regions. This effect was further confirmed by imaging the entire brain and brain slices. The resule entire brain and brain slices. The results indicated that NLCs with moderate additives are a promising controlled-release and drug-targeting system.

67

A New Multicolor Bioluminescence Imaging Platform to Investigate NF-?B Activity and Apoptosis in Human Breast Cancer Cells  

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Background Evaluation of novel drugs for clinical development depends on screening technologies and informative preclinical models. Here we developed a multicolor bioluminescent imaging platform to simultaneously investigate transcription factor NF-?B signaling and apoptosis. Methods The human breast cancer cell line (MDA-MB-231) was genetically modified to express green, red and blue light emitting luciferases to monitor cell number and viability, NF-?B promoter activity and to perform specific cell sorting and detection, respectively. The pro-luciferin substrate Z-DEVD-animoluciferin was employed to determine apoptotic caspase 3/7 activity. We used the cell line for the in vitro evaluation of natural compounds and in vivo optical imaging of tumor necrosis factor TNF?-induced NF-?B activation. Results Celastrol, resveratrol, sulphoraphane and curcumin inhibited the NF-?B promoter activity significantly and in a dose dependent manner. All compounds except resveratrol induced caspase 3/7 dependent apoptosis. Multicolor bioluminescence in vivo imaging allowed the investigation of tumor growth and NF-?B induction in a mouse model of breast cancer. Conclusion Our new method provides an imaging platform for the identification, validation, screening and optimization of compounds acting on NF-?B signaling and apoptosis both in vitro and in vivo. PMID:24465597

Mezzanotte, Laura; An, Na; Mol, Isabel M.; Lowik, Clemens W. G. M.; Kaijzel, Eric L.

2014-01-01

68

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

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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

69

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Wang, Hai-juan; Meng, Xi-ting; Luan, Qing-chun; Liang, Xiao; Zhang, Xue-yan; Fu, Ming; Lin, Chen; Qian, Hai-li

2012-01-01

70

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

71

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

72

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

73

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

74

A non-invasive in vivo imaging system to study dissemination of bioluminescent Yersinia pestis CO92 in a mouse model of pneumonic plague.  

Science.gov (United States)

The gold standard in microbiology for monitoring bacterial dissemination in infected animals has always been viable plate counts. This method, despite being quantitative, requires sacrificing the infected animals. Recently, however, an alternative method of in vivo imaging of bioluminescent bacteria (IVIBB) for monitoring microbial dissemination within the host has been employed. Yersinia pestis is a Gram-negative bacterium capable of causing bubonic, septicemic, and pneumonic plague. In this study, we compared the conventional counting of bacterial colony forming units (cfu) in the various infected tissues to IVIBB in monitoring Y. pestis dissemination in a mouse model of pneumonic plague. By using a transposon mutagenesis system harboring the luciferase (luc) gene, we screened approximately 4000 clones and obtained a fully virulent, luc-positive Y. pestis CO92 (Y. pestis-luc2) reporter strain in which transposition occurred within the largest pMT1 plasmid which possesses murine toxin and capsular antigen encoding genes. The aforementioned reporter strain and the wild-type CO92 exhibited similar growth curves, formed capsule based on immunofluorescence microscopy and flow cytometry, and had a similar LD(50). Intranasal infection of mice with 15 LD(50) of CO92-luc2 resulted in animal mortality by 72 h, and an increasing number of bioluminescent bacteria were observed in various mouse organs over a 24-72 h period when whole animals were imaged. However, following levofloxacin treatment (10 mg/kg/day) for 6 days 24 h post infection, no luminescence was observed after 72 h of infection, indicating that the tested antimicrobial killed bacteria preventing their detection in host peripheral tissues. Overall, we demonstrated that IVIBB is an effective and non-invasive way of monitoring bacterial dissemination in animals following pneumonic plague having strong correlation with cfu, and our reporter CO92-luc2 strain can be employed as a useful tool to monitor the efficacy of antimicrobial countermeasures in real time. PMID:23063826

Sha, Jian; Rosenzweig, Jason A; Kirtley, Michelle L; van Lier, Christina J; Fitts, Eric C; Kozlova, Elena V; Erova, Tatiana E; Tiner, Bethany L; Chopra, Ashok K

2013-02-01

75

Chemiluminescence and bioluminescence microbe detection  

Science.gov (United States)

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

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

1978-01-01

76

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

Science.gov (United States)

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.

77

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

78

Glioblastoma therapy with cytotoxic mesenchymal stromal cells optimized by bioluminescence imaging of tumor and therapeutic cell response.  

Science.gov (United States)

Genetically modified adipose tissue derived mesenchymal stromal cells (hAMSCs) with tumor homing capacity have been proposed for localized therapy of chemo- and radiotherapy resistant glioblastomas. We demonstrate an effective procedure to optimize glioblastoma therapy based on the use of genetically modified hAMSCs and in vivo non invasive monitoring of tumor and therapeutic cells. Glioblastoma U87 cells expressing Photinus pyralis luciferase (Pluc) were implanted in combination with hAMSCs expressing a trifunctional Renilla reniformis luciferase-red fluorescent protein-thymidine kinase reporter in the brains of SCID mice that were subsequently treated with ganciclovir (GCV). The resulting optimized therapy was effective and monitoring of tumor cells by bioluminescence imaging (BLI) showed that after 49 days GCV treatment reduced significantly the hAMSC treated tumors; by a factor of 10(4) relative to controls. Using a Pluc reporter regulated by an endothelial specific promoter and in vivo BLI to image hAMSC differentiation we gained insight on the therapeutic mechanism. Implanted hAMSCs homed to tumor vessels, where they differentiated to endothelial cells. We propose that the tumor killing efficiency of genetically modified hAMSCs results from their association with the tumor vascular system and should be useful vehicles to deliver localized therapy to glioblastoma surgical borders following tumor resection. PMID:22529983

Alieva, Maria; Bagó, Juli R; Aguilar, Elisabet; Soler-Botija, Carolina; Vila, Olaia F; Molet, Joan; Gambhir, Sanjiv S; Rubio, Nuria; Blanco, Jerónimo

2012-01-01

79

Bioluminescence imaging of chronic Trypanosoma cruzi infections reveals tissue-specific parasite dynamics and heart disease in the absence of locally persistent infection  

Science.gov (United States)

Summary Chronic Trypanosoma cruzi infections lead to cardiomyopathy in 20–30% of cases. A causal link between cardiac infection and pathology has been difficult to establish because of a lack of robust methods to detect scarce, focally distributed parasites within tissues. We developed a highly sensitive bioluminescence imaging system based on T.?cruzi expressing a novel luciferase that emits tissue-penetrating orange-red light. This enabled long-term serial evaluation of parasite burdens in individual mice with an in vivo limit of detection of significantly less than 1000 parasites. Parasite distributions during chronic infections were highly focal and spatiotemporally dynamic, but did not localize to the heart. End-point ex vivo bioluminescence imaging allowed tissue-specific quantification of parasite loads with minimal sampling bias. During chronic infections, the gastro-intestinal tract, specifically the colon and stomach, was the only site where T.?cruzi infection was consistently observed. Quantitative PCR-inferred parasite loads correlated with ex vivo bioluminescence and confirmed the gut as the parasite reservoir. Chronically infected mice developed myocarditis and cardiac fibrosis, despite the absence of locally persistent parasites. These data identify the gut as a permissive niche for long-term T.?cruzi infection and show that canonical features of Chagas disease can occur without continual myocardium-specific infection. PMID:24712539

Lewis, Michael D; Fortes Francisco, Amanda; Taylor, Martin C; Burrell-Saward, Hollie; McLatchie, Alex P; Miles, Michael A; Kelly, John M

2014-01-01

80

Bio-luminescent imaging and characterization of organ-specific metastasis of human cancer in NOD/SCID mice  

Science.gov (United States)

Many clinical evidences demonstrate that the sites of distant metastasis are not random and certain malignant tumors show a tendency to develop metastases in specific organs (e.g., brain, liver, and lungs). However, an appropriate animal model to characterize the metastatic nature of transplantable human cancer cell lines has not been reported well. Recent advances in bio-luminescent imaging (BLI) technologies have facilitated the quantitative analysis of various cellular processes in vivo. To visualize the fate of tumor progression in the living mice, we are constructing a luciferaseexpressing human cancer cell library (including melanoma, colon, breast, and prostate cancer). Herein we demonstrate that the BLI technology in couple with a fine ultrasonic guidance realizes cancer cell-type dependent metastasis to the specific organs. For example, some melanoma cell lines showed frequent metastasis to brain, lungs, and lymph nodes in the mouse model. Notably, reflecting the clinical features of melanoma, breast, and prostate cancer, some of the cell lines showed preferential metastasis to the brain. Moreover, these cellular resources for BLI allow a high throughput screening for potential anti-cancer drugs. Thus, this BLI-mediated additional strategy with the luciferase-expressing cancer cell resources should promote many translational studies for human cancer therapy.

Chun, Nicole A. L.; Murakami, Takashi

2010-02-01

 
 
 
 
81

Bioluminescence resonance energy transfer (BRET) imaging of protein-protein interactions within deep tissues of living subjects.  

Science.gov (United States)

Identifying protein-protein interactions (PPIs) is essential for understanding various disease mechanisms and developing new therapeutic approaches. Current methods for assaying cellular intermolecular interactions are mainly used for cells in culture and have limited use for the noninvasive assessment of small animal disease models. Here, we describe red light-emitting reporter systems based on bioluminescence resonance energy transfer (BRET) that allow for assaying PPIs both in cell culture and deep tissues of small animals. These BRET systems consist of the recently developed Renilla reniformis luciferase (RLuc) variants RLuc8 and RLuc8.6, used as BRET donors, combined with two red fluorescent proteins, TagRFP and TurboFP635, as BRET acceptors. In addition to the native coelenterazine luciferase substrate, we used the synthetic derivative coelenterazine-v, which further red-shifts the emission maxima of Renilla luciferases by 35 nm. We show the use of these BRET systems for ratiometric imaging of both cells in culture and deep-tissue small animal tumor models and validate their applicability for studying PPIs in mice in the context of rapamycin-induced FK506 binding protein 12 (FKBP12)-FKBP12 rapamycin binding domain (FRB) association. These red light-emitting BRET systems have great potential for investigating PPIs in the context of drug screening and target validation applications. PMID:21730157

Dragulescu-Andrasi, Anca; Chan, Carmel T; De, Abhijit; Massoud, Tarik F; Gambhir, Sanjiv S

2011-07-19

82

In Vivo Bioluminescence Tumor Imaging of RGD Peptide-modified Adenoviral Vector Encoding Firefly Luciferase Reporter Gene  

Science.gov (United States)

Purpose The goal of this study is to demonstrate the feasibility of chemically modified human adenovirus (Ad) vectors for tumor retargeting. Procedures E1- and E3-deleted Ad vectors carrying firefly luciferase reporter gene under cytomegalovirus promoter (AdLuc) was surface-modified with cyclic arginine–glycine–aspartic acid (RGD) peptides through a bifunctional poly(ethyleneglycol) linker (RGD-PEG-AdLuc) for integrin ?v?3 specific delivery. The Coxsackie and adenovirus viral receptor (CAR) and integrin ?v?3 expression in various tumor cell lines was determined by reverse transcriptase PCR and fluorescence-activated cell sorting. Bioluminescence imaging was performed in vitro and in vivo to evaluate RGD-modified AdLuc infectivity. Results RGD-PEG-AdLuc abrogated the native CAR tropism and exhibited significantly enhanced transduction efficiency of integrin-positive tumors than AdLuc through intravenous administration. Conclusion This approach provides a robust platform for site-specific gene delivery and noninvasive monitoring of the transgene delivery efficacy and homing. PMID:17297551

Niu, Gang; Xiong, Zhengming; Cheng, Zhen; Cai, Weibo; Gambhir, Sanjiv S.; Xing, Lei; Chen, Xiaoyuan

2014-01-01

83

Bioluminescent and micro-computed tomography imaging of bone repair induced by fibrin-binding growth factors.  

Science.gov (United States)

In this work we have evaluated the capacity of bone morphogenetic protein-2 (BMP-2) and fibrin-binding platelet-derived growth factor-BB (PDGF-BB) to support cell growth and induce bone regeneration using two different imaging technologies to improve the understanding of structural and organizational processes participating in tissue repair. Human mesenchymal stem cells from adipose tissue (hAMSCs) expressing two luciferase genes, one under the control of the cytomegalovirus (CMV) promoter and the other under the control of a tissue-specific promoter (osteocalcin or platelet endothelial cell adhesion molecule), were seeded in fibrin matrices containing BMP-2 and fibrin-binding PDGF-BB, and further implanted intramuscularly or in a mouse calvarial defect. Then, cell growth and bone regeneration were monitored by bioluminescence imaging (BLI) to analyze the evolution of target gene expression, indicative of cell differentiation towards the osteoblastic and endothelial lineages. Non-invasive imaging was supplemented with micro-computed tomography (?CT) to evaluate bone regeneration and high-resolution ?CT of vascular casts. Results from BLI showed hAMSC growth during the first week in all cases, followed by a rapid decrease in cell number; as well as an increment of osteocalcin but not PECAM-1 expression 3weeks after implantation. Results from ?CT show that the delivery of BMP-2 and PDGF-BB by fibrin induced the formation of more bone and improves vascularization, resulting in more abundant and thicker vessels, in comparison with controls. Although the inclusion of hAMSCs in the fibrin matrices made no significant difference in any of these parameters, there was a significant increment in the connectivity of the vascular network in defects treated with hAMSCs. PMID:24905933

Vila, Olaia F; Martino, Mikaël M; Nebuloni, Laura; Kuhn, Gisela; Pérez-Amodio, Soledad; Müller, Ralph; Hubbell, Jeffrey A; Rubio, Nuria; Blanco, Jerónimo

2014-10-01

84

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.

85

Evaluating reporter genes of different luciferases for optimized in vivo bioluminescence imaging of transplanted neural stem cells in the brain.  

Science.gov (United States)

Bioluminescence imaging (BLI) has become the method of choice for optical tracking of cells in small laboratory animals. However, the use of luciferases from different species, depending on different substrates and emitting at distinct wavelengths, has not been optimized for sensitive neuroimaging. In order to identify the most suitable luciferase, this quantitative study compared the luciferases Luc2, CBG99, PpyRE9 and hRluc. Human embryonic kidney (HEK-293) cells and mouse neural stem cells were transduced by lentiviral vector-mediated transfer to express one of the four luciferases, together with copGFP. A T2A peptide linker promoted stoichiometric expression between both imaging reporters and the comparison of cell populations upon flow cytometry. Cell dilution series were used to determine highest BLI sensitivity in vitro for Luc2. However, Coelenterazine h-dependent hRluc signals clearly exceeded d-luciferin-dependent BLI in vitro. For the quantitative in vivo analysis, cells were transplanted into mouse brain and BLI was performed including the recording of emission kinetics and spectral characteristics. Differences in light kinetics were observed for d-luciferin vs Coelenterazine h. The emission spectra of Luc2 and PpyRE9 remained almost unchanged, while the emission spectrum of CBG99 became biphasic. Most importantly, photon emission decreased in the order of Luc2, CBG99, PpyRE9 to hRluc. The feasibility of combining different luciferases for dual color and dual substrate neuroimaging was tested and discussed. This investigation provides the first complete quantitative comparison of different luciferases expressed by neural stem cells. It results in a clear recommendation of Luc2 as the best luciferase selection for in vivo neuroimaging. PMID:24375906

Mezzanotte, Laura; Aswendt, Markus; Tennstaedt, Annette; Hoeben, Rob; Hoehn, Mathias; Löwik, Clemens

2013-01-01

86

Bioluminescent Reaction by Immobilized Luciferase  

Science.gov (United States)

We have investigated an effect of immobilization of luciferase molecules at the optical fiber end on a bioluminescent reaction. The time dependence of measured count rates of emitted photons has been analyzed by fitting with numerical solution of differential equations including the effect of the product-inhibitor and the deactivation of the luciferase. Through the analysis, we have successfully extracted kinetic constants such as, reaction rate, number of active luciferase molecules, etc. Ratio of active molecules to total luciferase molecules in immobilization was one order of magnitude lower than that in solution. The reaction rate of the bioluminescent process was also different from the one of free luciferase in solution.

Tanaka, Ryuta; Takahama, Eriko; Iinuma, Masataka; Ikeda, Takeshi; Kadoya, Yutaka; Kuroda, Akio

87

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

Science.gov (United States)

Yersinia pestis causes an acute infection known as the plague. Conventional techniques to enumerate Y. pestis can be labor intensive and do not lend themselves to high throughput assays. In contrast, bioluminescent bioreporters produce light that can be detected using plate readers or optical imaging platforms to monitor bacterial populations as a function of luminescence. Here, we describe the development of two Y. pestis chromosomal-based luxCDABE bioreporters, Lux(PtolC) and Lux(PcysZK). These bioreporters use constitutive promoters to drive expression of luxCDABE that allow for sensitive detection of bacteria via bioluminescence in vitro. Importantly, both bioreporters demonstrate a direct correlation between bacterial numbers and bioluminescence, which allows for bioluminescence to be used to compare bacterial numbers. We demonstrate the use of these bioreporters to test antimicrobial inhibitors (Lux(PtolC)) and monitor intracellular survival (Lux(PtolC) and Lux(PcysZK)) in vitro. Furthermore, we show that Y. pestis infection of the mouse model can be monitored using whole animal optical imaging in real time. Using optical imaging, we observed Y. pestis dissemination and differentiated between virulence phenotypes in live animals via bioluminescence. Finally, we demonstrate that whole animal optical imaging can identify unexpected colonization patterns in mutant-infected animals. PMID:23071730

Sun, Yanwen; Connor, Michael G; Pennington, Jarrod M; Lawrenz, Matthew B

2012-01-01

88

In vivo bioluminescence imaging to evaluate systemic and topical antibiotics against community-acquired methicillin-resistant Staphylococcus aureus-infected skin wounds in mice.  

Science.gov (United States)

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) frequently causes skin and soft tissue infections, including impetigo, cellulitis, folliculitis, and infected wounds and ulcers. Uncomplicated CA-MRSA skin infections are typically managed in an outpatient setting with oral and topical antibiotics and/or incision and drainage, whereas complicated skin infections often require hospitalization, intravenous antibiotics, and sometimes surgery. The aim of this study was to develop a mouse model of CA-MRSA wound infection to compare the efficacy of commonly used systemic and topical antibiotics. A bioluminescent USA300 CA-MRSA strain was inoculated into full-thickness scalpel wounds on the backs of mice and digital photography/image analysis and in vivo bioluminescence imaging were used to measure wound healing and the bacterial burden. Subcutaneous vancomycin, daptomycin, and linezolid similarly reduced the lesion sizes and bacterial burden. Oral linezolid, clindamycin, and doxycycline all decreased the lesion sizes and bacterial burden. Oral trimethoprim-sulfamethoxazole decreased the bacterial burden but did not decrease the lesion size. Topical mupirocin and retapamulin ointments both reduced the bacterial burden. However, the petrolatum vehicle ointment for retapamulin, but not the polyethylene glycol vehicle ointment for mupirocin, promoted wound healing and initially increased the bacterial burden. Finally, in type 2 diabetic mice, subcutaneous linezolid and daptomycin had the most rapid therapeutic effect compared with vancomycin. Taken together, this mouse model of CA-MRSA wound infection, which utilizes in vivo bioluminescence imaging to monitor the bacterial burden, represents an alternative method to evaluate the preclinical in vivo efficacy of systemic and topical antimicrobial agents. PMID:23208713

Guo, Yi; Ramos, Romela Irene; Cho, John S; Donegan, Niles P; Cheung, Ambrose L; Miller, Lloyd S

2013-02-01

89

Development of a novel liposomal nanodelivery system for bioluminescence imaging and targeted drug delivery in ErbB2-overexpressing metastatic ovarian carcinoma.  

Science.gov (United States)

Liposomes as targeted drug delivery systems are an emerging strategy in the treatment of cancer to selectively target tumors or genes. In this study, we generated the recombinant protein, EC1-GLuc, by fusing the EC1 peptide, an artificial ligand of ErbB2, with Gaussia luciferase (GLuc). The purified EC1-GLuc was conjugated with a nickel-chelating liposome to construct the EC1-GLuc-liposome. In vitro experiments revealed that the EC1-GLuc-liposome selectively targeted and internalized into ErbB2-overexpressing SKOv3 cells for bioluminescence imaging. A cell-impermeable fluorescence dye (HPTS) encapsulated in the EC-GLuc-liposome was efficiently delivered into the SKOv3 cells. In addition, the EC1-GLuc-liposome also targeted metastatic SKOv3 tumors for bioluminescence imaging and effectively delivered HPTS into metastatic tumors in vivo. Therefore, the present study demonstrates the novel EC1-GLuc-liposome to be an effective theranostic system for monitoring and treating ErbB2-overexpressing metastatic ovarian carcinoma through a combination of targeted molecular imaging and DDS. PMID:25190023

Han, Xiao-Jian; Wei, Yong-Fang; Wan, Yu-Ying; Jiang, Li-Ping; Zhang, Jian-Feng; Xin, Hong-Bo

2014-11-01

90

Development of a novel liposomal nanodelivery system for bioluminescence imaging and targeted drug delivery in ErbB2-overexpressing metastatic ovarian carcinoma  

Science.gov (United States)

Liposomes as targeted drug delivery systems are an emerging strategy in the treatment of cancer to selectively target tumors or genes. In this study, we generated the recombinant protein, EC1-GLuc, by fusing the EC1 peptide, an artificial ligand of ErbB2, with Gaussia luciferase (GLuc). The purified EC1-GLuc was conjugated with a nickel-chelating liposome to construct the EC1-GLuc-liposome. In vitro experiments revealed that the EC1-GLuc-liposome selectively targeted and internalized into ErbB2-overexpressing SKOv3 cells for bioluminescence imaging. A cell-impermeable fluorescence dye (HPTS) encapsulated in the EC-GLuc-liposome was efficiently delivered into the SKOv3 cells. In addition, the EC1-GLuc-liposome also targeted metastatic SKOv3 tumors for bioluminescence imaging and effectively delivered HPTS into metastatic tumors in vivo. Therefore, the present study demonstrates the novel EC1-GLuc-liposome to be an effective theranostic system for monitoring and treating ErbB2-overexpressing metastatic ovarian carcinoma through a combination of targeted molecular imaging and DDS. PMID:25190023

HAN, XIAO-JIAN; WEI, YONG-FANG; WAN, YU-YING; JIANG, LI-PING; ZHANG, JIAN-FENG; XIN, HONG-BO

2014-01-01

91

Practical reconstruction method for bioluminescence tomography  

Science.gov (United States)

Bioluminescence tomography (BLT) is used to localize and quantify bioluminescent sources in a small living animal. By advancing bioluminescent imaging to a tomographic framework, it helps to diagnose diseases, monitor therapies and facilitate drug development. In this paper, we establish a direct linear relationship between measured surface photon density and an unknown bioluminescence source distribution by using a finite-element method based on the diffusion approximation to the photon propagation in biological tissue. We develop a novel reconstruction algorithm to recover the source distribution. This algorithm incorporates a priori knowledge to define the permissible source region in order to enhance numerical stability and efficiency. Simulations with a numerical mouse chest phantom demonstrate the feasibility of the proposed BLT algorithm and reveal its performance in terms of source location, density, and robustness against noise. Lastly, BLT experiments are performed to identify the location and power of two light sources in a physical mouse chest phantom.

Cong, Wenxiang; Wang, Ge; Kumar, Durairaj; Liu, Yi; Jiang, Ming; Wang, Lihong V.; Hoffman, Eric A.; McLennan, Geoffrey; McCray, Paul B.; Zabner, Joseph; Cong, Alexander

2005-09-01

92

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.

93

Fungi bioluminescence revisited.  

Science.gov (United States)

A review of the research conducted during the past 30 years on the distribution, taxonomy, phylogeny, ecology, physiology and bioluminescence mechanisms of luminescent fungi is presented. We recognize 64 species of bioluminescent fungi belonging to at least three distinct evolutionary lineages, termed Omphalotus, Armillaria and mycenoid. An accounting of their currently accepted names, distributions, citations reporting luminescence and whether their mycelium and/or basidiomes emit light are provided. We address the physiological and ecological aspects of fungal bioluminescence and provide data on the mechanisms responsible for bioluminescence in the fungi. PMID:18264584

Desjardin, Dennis E; Oliveira, Anderson G; Stevani, Cassius V

2008-02-01

94

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

Science.gov (United States)

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) of any reported bioluminescent protein that utilizes its natural substrate coelenterazine, a benefit of which is demonstrated at various tissue depths in small animals. The imaging utility of BRET3 at the single-cell level is demonstrated using an intramolecular sensor incorporating two mammalian target of rapamycin pathway proteins (FKBP12 and FRB) that dimerize only in the presence of rapamycin. With its increased photon intensity, red-shifted light output, and good spectral resolution (approximately 85 nm), BRET3 shows improved spatial and temporal resolution for measuring intracellular events in single cells and in living small animal models. The development of further BRET3-based assays will allow imaging of protein-protein interactions using a single assay directly scalable from intact living cells to small living subjects, allowing accelerated drug discovery. PMID:19351700

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

2009-08-01

95

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

Directory of Open Access Journals (Sweden)

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

96

Bioluminescence resonance energy transfer (BRET) imaging of protein–protein interactions within deep tissues of living subjects  

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Identifying protein–protein interactions (PPIs) is essential for understanding various disease mechanisms and developing new therapeutic approaches. Current methods for assaying cellular intermolecular interactions are mainly used for cells in culture and have limited use for the noninvasive assessment of small animal disease models. Here, we describe red light-emitting reporter systems based on bioluminescence resonance energy transfer (BRET) that allow for assaying PPIs both in cell cultu...

Dragulescu-andrasi, Anca; Chan, Carmel T.; De, Abhijit; Massoud, Tarik F.; Gambhir, Sanjiv S.

2011-01-01

97

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.; Widder, Edith

2009-06-17

98

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

99

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.

100

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

 
 
 
 
101

Bioluminescence imaging of point sources implanted in small animals post mortem: evaluation of a method for estimating source strength and depth  

International Nuclear Information System (INIS)

The performance of a simple approach for the in vivo reconstruction of bioluminescent point sources in small animals was evaluated. The method uses the diffusion approximation as a forward model of light propagation from a point source in a homogeneous tissue to find the source depth and power. The optical properties of the tissue are estimated from reflectance images obtained at the same location on the animal. It was possible to localize point sources implanted in mice, 2-8 mm deep, to within 1 mm. The same performance was achieved for sources implanted in rat abdomens when the effects of tissue surface curvature were eliminated. The source power was reconstructed within a factor of 2 of the true power for the given range of depths, even though the apparent brightness of the source varied by several orders of magnitude. The study also showed that reconstructions using optical properties measured in situ were superior to those based on data in the literature

102

Enhanced healing of diabetic wounds by topical administration of adipose tissue-derived stromal cells overexpressing stromal-derived factor-1: biodistribution and engraftment analysis by bioluminescent imaging.  

Science.gov (United States)

Chronic ulcers represent a major health problem in diabetic patients resulting in pain and discomfort. Conventional therapy does not guarantee adequate wound repair. In diabetes, impaired healing is partly due to poor endothelial progenitor cells mobilisation and homing, with altered levels of the chemokine stromal-derived factor-1 (SDF-1) at the wound site. Adipose tissue-associated stromal cells (AT-SCs) can provide an accessible source of progenitor cells secreting proangiogenic factors and differentiating into endothelial-like cells. We demonstrated that topical administration of AT-SCs genetically modified ex vivo to overexpress SDF-1, promotes wound healing into diabetic mice. In particular, by in vivo bioluminescent imaging analysis, we monitored biodistribution and survival after transplantation of luciferase-expressing cells. In conclusion, this study indicates the therapeutic potential of AT-SCs administration in wound healing, through cell differentiation, enhanced cellular recruitment at the wound site, and paracrine effects associated with local growth-factors production. PMID:21234108

Di Rocco, Giuliana; Gentile, Antonietta; Antonini, Annalisa; Ceradini, Francesca; Wu, Joseph C; Capogrossi, Maurizio C; Toietta, Gabriele

2010-01-01

103

Bioluminescence imaging of point sources implanted in small animals post mortem: evaluation of a method for estimating source strength and depth  

Energy Technology Data Exchange (ETDEWEB)

The performance of a simple approach for the in vivo reconstruction of bioluminescent point sources in small animals was evaluated. The method uses the diffusion approximation as a forward model of light propagation from a point source in a homogeneous tissue to find the source depth and power. The optical properties of the tissue are estimated from reflectance images obtained at the same location on the animal. It was possible to localize point sources implanted in mice, 2-8 mm deep, to within 1 mm. The same performance was achieved for sources implanted in rat abdomens when the effects of tissue surface curvature were eliminated. The source power was reconstructed within a factor of 2 of the true power for the given range of depths, even though the apparent brightness of the source varied by several orders of magnitude. The study also showed that reconstructions using optical properties measured in situ were superior to those based on data in the literature.

Comsa, D C; Farrell, T J; Patterson, M S [Juravinski Cancer Centre and McMaster University, 699 Concession Street, Hamilton, ON L8V 5C2 (Canada)

2007-09-07

104

Bioluminescence: Living Light  

Science.gov (United States)

This National Geographic lesson plan explores bioluminescent creatures and the underwater world in which they live. Using shoeboxes and black paint, students are directed to build a deep-sea model and inhabit it with fish made out of black construction paper. Students then use the model to describe how organisms use bioluminescence and learn about its use as camouflage. In addition to a detailed protocol, the lesson plan includes suggestions for assessments and links to additional information.

Xpeditions, National G.

105

Bioluminescence tomography by an iterative reweighted (l)2 norm optimization.  

Science.gov (United States)

Bioluminescence tomography is a promising tool in preclinical research, enabling noninvasive real-time in vivo imaging as well as quantitative analysis in small animal studies. Due to the difficulty of reconstruction, continuous efforts are still made to find more practical and efficient approaches. In this paper, we present an iterative reweighted l2-norm optimization incorporating anatomical structures in order to enhance the performance of bioluminescence tomography. The structure priors have been utilized to generate a heterogeneous mouse model by extracting the internal organs and tissues, which can assist in establishing a more precise photon diffusion model, as well as reflecting a more specific position of the reconstruction results inside the mouse. To evaluate the performance of the iterative reweighted approach, several numerical simulation studies including comparative analyses and multisource cases have been conducted to reconstruct the same datasets. The results suggest that the proposed method is able to ensure the accuracy, robustness, and efficiency of bioluminescence tomography. Finally, an in vivo experiment was performed to further validate its feasibility in a practical application. PMID:23974521

Ping Wu; Yifang Hu; Kun Wang; Jie Tian

2014-01-01

106

Action of ?-radiation on bioluminescence of Noctiluca miliaris  

International Nuclear Information System (INIS)

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

107

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

108

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.

2006-01-01

109

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

110

Thoughts on the diversity of convergent evolution of bioluminescence on earth  

Science.gov (United States)

The widespread independent evolution of analogous bioluminescent systems is one of the most impressive and diverse examples of convergent evolution on earth. There are roughly 30 extant bioluminescent systems that have evolved independently on Earth, with each system likely having unique enzymes responsible for catalysing the bioluminescent reaction. Bioluminescence is a chemical reaction involving a luciferin molecule and a luciferase or photoprotein that results in the emission of light. Some independent systems utilize the same luciferin, such as the use of tetrapyrrolic compounds by krill and dinoflagellates, and the wide use of coelenterazine by marine organisms, while the enzymes involved are unique. One common thread among all the different bioluminescent systems is the requirement of molecular oxygen. Bioluminescence is found in most forms of life, especially marine organisms. Bioluminescence in known to benefit the organism by: attraction, repulsion, communication, camouflage, and illumination. The marine ecosystem is significantly affected by bioluminescence, the only light found in the pelagic zone and below is from bioluminescent organisms. Transgenic bioluminescent organisms have revolutionized molecular research, medicine and the biotechnology industry. The use of bioluminescence in studying molecular pathways and disease allows for non-invasive and real-time analysis. Bioluminescence-based assays have been developed for several analytes by coupling luminescence to many enzyme-catalysed reactions.

Waldenmaier, Hans E.; Oliveira, Anderson G.; Stevani, Cassius V.

2012-10-01

111

Toona sinensis and its major bioactive compound gallic acid inhibit LPS-induced inflammation in nuclear factor-?B transgenic mice as evaluated by in vivo bioluminescence imaging.  

Science.gov (United States)

In the present study, we investigated the anti-inflammatory effects of a nutritious vegetable Toona sinensis (leaf extracts, TS) and its major bioactive compound gallic acid (GA) by analysing LPS-induced NF-?B activation in transgenic mice, using bioluminescence imaging. Mice were challenged intraperitoneally with LPS (1mg/kg) and treated orally with TS or GA (100 or 5mg/kg, respectively). In vivo and ex vivo imaging showed that LPS increased NF-?B luminescence in the abdominal region, which was significantly inhibited by TS or GA. Immunohistochemical and ELISA analyses confirmed that TS and GA inhibited LPS-induced NF-?B, interleukin-1?, and tumour necrosis factor-? expression. Microarray analysis revealed that biological pathways associated with metabolism and the immune responses were affected by TS or GA. Particularly, LPS-induced thioredoxin-like 4B (TXNL4B) 2 expression in the small intestine, and TXNL4B, iNOS, and COX-2 expression in RAW 264.7 cells were significantly inhibited by TS or GA. Thus, the anti-inflammatory potential of TS was mediated by the downregulation of NF-?B pathway. PMID:23122080

Hsiang, Chien-Yun; Hseu, You-Cheng; Chang, Yi-Chih; Kumar, K J Senthil; Ho, Tin-Yun; Yang, Hsin-Ling

2013-01-15

112

Bioluminescence of Marine Dinoflagellates  

Science.gov (United States)

Portable light-baffled underwater photometers have been designed for the measurement of dinoflagellate bioluminescence by day and night. Maximal light emission is obtained by mechanical stimulation in a defined volume. The pump which stimulates the dinoflagellates also constantly replenishes the sample volume so that continuous measurements are possible. Evidence for both diurnal variation and vertical migration is presented. Using luminous bacteria for calibration a single dinoflagellate has been found to emit of the order of 1010 light quanta per flash. The technique suggests that large scale mapping of bioluminescence is feasible. PMID:19873546

Seliger, H. H.; Fastie, W. G.; Taylor, W. R.; McElroy, W. D.

1962-01-01

113

Information-theoretic method for wavelength selection in bioluminescence tomography  

Science.gov (United States)

Practical imaging constraints restrict the number of wavelengths that can be measured in a single Biolumines- cence Tomography imaging session, but it is unclear which set of measurement wavelengths is optimal, in the sense of providing the most information about the bioluminescent source. Mutual Information was used to integrate knowledge of the type of bioluminescent source likely to be present, the optical properties of tissue and physics of light propagation, and the noise characteristics of the imaging system, in order to quantify the information contained in measurements at different sets of wavelengths. The approach was applied to a two-dimensional sim- ulation of Bioluminescence Tomography imaging of a mouse, and the results indicate that different wavelengths and sets of wavelengths contain different amounts of information. When imaging at a single wavelength, 580nm was found to be optimal, and when imaging at two wavelengths, 570nm and 580nm were found to be optimal. Examination of the dispersion of the posterior distributions for single wavelengths suggests that information regarding the location of the centre of the bioluminescence distribution is relatively independent of wavelength, whilst information regarding the width of the bioluminescence distribution is relatively wavelength specific.

Basevi, Hector R. A.; Guggenheim, James A.; Dehghani, Hamid; Styles, Iain B.

2013-06-01

114

Bioluminescent bioreporter sensing of foodborne toxins  

Science.gov (United States)

Histamine is the primary etiological agent in the foodborne disease scombrotoxicosis, one of the most common food toxicities related to fish consumption. Procedures for detecting histamine in fish products are available, but are often too expensive or too complex for routine use. As an alternative, a bacterial bioluminescent bioreporter has been constructed to develop a biosensor system that autonomously responds to low levels of histamine. The bioreporter contains a promoterless Photorhabdus luminescens lux operon (luxCDABE) fused with the Vibrio anguillarum angR regulatory gene promoter of the anguibactin biosynthetic operon. The bioreporter emitted 1.46 times more bioluminescence than background, 30 minutes after the addition of 100mM histamine. However, specificity was not optimal, as this biosensor generated significant bioluminescence in the presence of L-proline and L-histidine. As a means towards improving histamine specificity, the promoter region of a histamine oxidase gene from Arthrobacter globiformis was cloned upstream of the promotorless lux operon from Photorhabdus luminescens. This recently constructed whole-cell, lux-based bioluminescent bioreporter is currently being tested for optimal performance in the presence of histamine in order to provide a rapid, simple, and inexpensive model sensor for the detection of foodborne toxins.

Fraley, Amanda C.; Ripp, Steven; Sayler, Gary S.

2004-06-01

115

Bioluminescent properties of obelin and aequorin with novel coelenterazine analogues.  

Science.gov (United States)

The main analytical use of Ca(2+)-regulated photoproteins from luminous coelenterates is for real-time non-invasive visualization of intracellular calcium concentration ([Ca(2+)]i) dynamics in cells and whole organisms. A limitation of this approach for in vivo deep tissue imaging is the fact that blue light emitted by the photoprotein is highly absorbed by tissue. Seven novel coelenterazine analogues were synthesized and their effects on the bioluminescent properties of recombinant obelin from Obelia longissima and aequorin from Aequorea victoria were evaluated. Only analogues having electron-donating groups (m-OCH3 and m-OH) on the C6 phenol moiety or an extended resonance system at the C8 position (1-naphthyl and ?-styryl analogues) showed a significant red shift of light emission. Of these, only the ?-styryl analogue displayed a sufficiently high light intensity to allow eventual tissue penetration. The possible suitability of this compound for in vivo assays was corroborated by studies with aequorin which allowed the monitoring of [Ca(2+)]i dynamics in cultured CHO cells and in hippocampal brain slices. Thus, the ?-styryl coelenterazine analogue might be potentially useful for non-invasive, in vivo bioluminescence imaging in deep tissues of small animals. PMID:24553660

Gealageas, Ronan; Malikova, Natalia P; Picaud, Sandrine; Borgdorff, Aren J; Burakova, Ludmila P; Brûlet, Philippe; Vysotski, Eugene S; Dodd, Robert H

2014-04-01

116

Real-time bioluminescence imaging of polycythemia vera development in mice  

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Abstrac Polycythemia vera (PV) is a myeloproliferative disorder involving hematopoietic stem cells. A recurrent somatic missense mutation in JAK2 (JAK2V617F) is thought to play a causal role in PV. Therefore, targeting Jak2 will likely provide a molecular mechanism-based therapy for PV. To facilitate the development of such new and specific therapeutics, a suitable and well characterized preclinical animal model is essential. Although several mouse models of PV have been reported, ...

2009-01-01

117

TIMED Imaging Photometer Experiment (TIPE)  

Science.gov (United States)

This document contains a summary of the TIMED Imaging Photometer Experiment (TIPE) instrument study at the time of the termination of project due to TIPE being de-selected from the Thermosphere, Ionosphere and Mesosphere Energetics and Dynamics (TIMED) mission.

Mende, Stephen B.; Fritts, D. C.; Hecht, James H.; Killeen, T. L.; Llewellyn, Edward J.; Lowe, Robert P.; Mcdade, Ian C.; Ross, Martin N.; Swenson, Gary R.; Turnbull, David N.

1994-01-01

118

Bioluminescence assays: effects of quinones and phenols.  

Science.gov (United States)

The influence of a series of quinones and phenols on bacteria bioluminescence systems was investigated. Three bioluminescence systems used in ecological monitoring were compared: (1) water-soluble; (2) immobilized in starch gel coupled enzyme systems: NADH:FMN-oxidoreductase-luciferase; (3) luminescent bacteria. Bioluminescence inhibition constants of quinones and phenols and bioluminescence induction periods were compared. These kinetic parameters are proportional to quinone concentrations and depend on the quinone redox potential. Different effects of the substances are related to structure and properties of the bioluminescence systems. The set of bioluminescence assays for quinones and phenols monitoring should include two bioluminescence systems: 1 (or 2) and 3. PMID:12568457

Kudryasheva, N; Vetrova, E; Kuznetsov, A; Kratasyuk, V; Stom, D

2002-10-01

119

Bioluminescence imaging of therapy response does not correlate with FDG-PET response in a mouse model of Burkitt lymphoma.  

Science.gov (United States)

Since the development and evaluation of novel anti-cancer therapies require molecular insight in the disease state, both FDG-PET and BLI imaging were evaluated in a Burkitt B-cell lymphoma xenograft model treated with cyclophosphamide or temsirolimus. Daudi xenograft mice were treated with either cyclophosphamide or temsirolimus and imaged with BLI and FDG-PET on d0 (before treatment), d2, d4, d7, d9 and d14 following the start of therapy. Besides tumor volume changes, therapy response was assessed with immunohistochemical analysis (apoptosis). BLI revealed a flare following both therapeutics that was significantly higher when compared to control tumors. FDG-PET decreased immediatelly, long before the tumor reduced in size. Late after therapy, BLI signal intensities decreased significantly compared to baseline subsequent to tumor size reduction while apoptosis was immediately induced following both treatment regimen. Unlike FDG, BLI was not able to reflect reduced levels of viable cells and was not able to predict tumor size response and apoptosis response. PMID:23133822

Saint-Hubert, Marijke De; Devos, Ellen; Ibrahimi, Abdelilah; Debyser, Zeger; Mortelmans, Luc; Mottaghy, Felix M

2012-01-01

120

Bioluminescent Imaging Reveals Divergent Viral Pathogenesis in Two Strains of Stat1-Deficient Mice, and in ?ß? Interferon Receptor-Deficient Mice  

Science.gov (United States)

Pivotal components of the IFN response to virus infection include the IFN receptors (IFNR), and the downstream factor signal transducer and activator of transcription 1 (Stat1). Mice deficient for Stat1 and IFNR (Stat1?/? and IFN?ß?R?/? mice) lack responsiveness to IFN and exhibit high sensitivity to various pathogens. Here we examined herpes simplex virus type 1 (HSV-1) pathogenesis in Stat1?/? mice and in IFN?ß?R?/? mice following corneal infection and bioluminescent imaging. Two divergent and paradoxical patterns of infection were observed. Mice with an N-terminal deletion in Stat1 (129Stat1?/? (N-term)) had transient infection of the liver and spleen, but succumbed to encephalitis by day 10 post-infection. In stark contrast, infection of IFN?ß?R?/? mice was rapidly fatal, with associated viremia and fulminant infection of the liver and spleen, with infected infiltrating cells being primarily of the monocyte/macrophage lineage. To resolve the surprising difference between Stat1?/? and IFN?ß?R?/? mice, we infected an additional Stat1?/? strain deleted in the DNA-binding domain (129Stat1?/? (DBD)). These 129Stat1?/? (DBD) mice recapitulated the lethal pattern of liver and spleen infection seen following infection of IFN?ß?R?/? mice. This lethal pattern was also observed when 129Stat1?/? (N-term) mice were infected and treated with a Type I IFN-blocking antibody, and immune cells derived from 129Stat1?/? (N-term) mice were shown to be responsive to Type I IFN. These data therefore show significant differences in viral pathogenesis between two commonly-used Stat1?/? mouse strains. The data are consistent with the hypothesis that Stat1?/? (N-term) mice have residual Type I IFN receptor-dependent IFN responses. Complete loss of IFN signaling pathways allows viremia and rapid viral spread with a fatal infection of the liver. This study underscores the importance of careful comparisons between knockout mouse strains in viral pathogenesis, and may also be relevant to the causation of HSV hepatitis in humans, a rare but frequently fatal infection. PMID:21915277

Pasieka, Tracy Jo; Collins, Lynne; O'Connor, Megan A.; Chen, Yufei; Parker, Zachary M.; Berwin, Brent L.; Piwnica-Worms, David R.; Leib, David A.

2011-01-01

 
 
 
 
121

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

Science.gov (United States)

Bathyphotometer measurements of bioluminescence are used as a proxy for the abundance of luminescent organisms for studying population dynamics; the interaction of luminescent organisms with physical, chemical, and biological oceanographic processes; and spatial complexity especially in coastal areas. However, the usefulness of bioluminescence measurements has been limited by the inability to compare results from different bathyphotometer designs, or even the same bathyphotometer operating at different volume flow rates. The primary objective of this study was to compare measurements of stimulated bioluminescence of four species of cultured dinoflagellates, the most common source of bioluminescence in coastal waters, using two different bathyphotometer flow agitators as a function of bathyphotometer volume flow rate and dinoflagellate concentration. For both the NOSC and BIOLITE flow agitators and each species of dinoflagellate tested, there was a critical volume flow rate, above which average bioluminescence intensity, designated as bathyphotometer bioluminescence potential (BBP), remained relatively constant and scaled directly with dinoflagellate cell concentration. At supra-critical volume flow rates, the ratio of BIOLITE to NOSC BBP was nearly constant for the same species studied, but varied between species. The spatial pattern and residence time of flash trajectories within the NOSC flow agitator indicated the presence of dominant secondary recirculating flows, where most of the bioluminescence was detected. A secondary objective (appearing in the Appendix) was to study the feasibility of using NOSC BBP to scale flow-stimulated bioluminescence intensity across similar flow fields, where the contributing composition of luminescent species remained the same. Fully developed turbulent pipe flow was chosen because it is hydrodynamically well characterized. Average bioluminescence intensity in a 2.54-cm i.d. pipe was highly correlated with wall shear stress and BBP. This correlation, when further scaled by pipe diameter, effectively predicted bioluminescence intensity in fully developed turbulent flow in a 0.83-cm i.d. pipe. Determining similar correlations between other bathyphotometer flow agitators and flow fields will allow bioluminescence potential measurements to become a more powerful tool for the oceanographic community.

Latz, Michael I.; Rohr, Jim

2013-07-01

122

Bioluminescent Imaging Reveals Divergent Viral Pathogenesis in Two Strains of Stat1-Deficient Mice, and in ?ß? Interferon Receptor-Deficient Mice  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pivotal components of the IFN response to virus infection include the IFN receptors (IFNR), and the downstream factor signal transducer and activator of transcription 1 (Stat1). Mice deficient for Stat1 and IFNR (Stat1?/? and IFN?ß?R?/? mice) lack responsiveness to IFN and exhibit high sensitivity to various pathogens. Here we examined herpes simplex virus type 1 (HSV-1) pathogenesis in Stat1?/? mice and in IFN?ß?R?/? mice following corneal infection and bioluminescent i...

Pasieka, Tracy Jo; Collins, Lynne; O Connor, Megan A.; Chen, Yufei; Parker, Zachary M.; Berwin, Brent L.; Piwnica-worms, David R.; Leib, David A.

2011-01-01

123

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

124

Bioluminescence monitoring of photodynamic therapy response of rat gliosarcoma in vitro and in vivo  

Science.gov (United States)

Photodynamic Therapy (PDT) is a promising modality for tumor treatment that combines a photosensitizing agent and visible light resulting in the production of cytotoxic reactive oxygen species leading to cell death. Bioluminescence detection/imaging is a noninvasive technique that uses luciferase gene transfection together with administration of luciferin to generate detectable visible light. It can provide real-time assessment of tumor growth and therapeutic response. The aim of this study is to investigate the potential fo bioluminescence following animolevulinic acid (ALA)-mediated PDT. The in vitro results show a decrease of luminescence, with an excellent correlation to the number of viable cells. In vivo, the tumor growth was monitored using a cooled CCD camera, and ALA-PDT was performed 7-10 days post tumor implantation. The results show a decrease of the bioluminescence signal from the tumor that corresponds to a decrease of viable cells within the tumor, followed by re-growth at the sub-curative PDT doses used.

Moriyama, Eduardo H.; Bisland, Stuart K.; Lin, Annie; Bogaards, Arjen; Lilge, Lothar D.; Wilson, Brian C.

2003-06-01

125

Random matrix-based dimensionality reduction for bioluminescence tomography reconstruction  

Science.gov (United States)

We show how a random matrix can be used to reduce the dimensionality of the bioluminescence tomography reconstruction problem. A randomised low-rank approximation for the sensitivity matrix is computed, and we show how this can be used to reconstruct the bioluminescence source distribution on a randomised basis for the mesh nodes. The distribution on the original mesh can be found easily via a simple matrix multiplication. The majority of the computation required can be performed in advance of the reconstruction, and the reconstruction time itself is of the order milliseconds. This could allow for high frame rate real-time reconstructions to be performed.

Styles, Iain B.; Basevi, Hector R. A.; Guggenheim, James A.; Dehghani, Hamid

2013-06-01

126

Quantifying the activity of adenoviral E1A CR2 deletion mutants using renilla luciferase bioluminescence and 3'-deoxy-3'-[18F]fluorothymidine positron emission tomography imaging.  

Science.gov (United States)

The adenoviral E1A CR2 mutant dl922-947 has potent activity in ovarian cancer. We have used Renilla luciferase bioluminescence imaging to monitor viral E1A expression and replication and [18F]fluorothymidine positron emission tomography ([18F]FLT-PET) to quantify the activity of dl922-947 in vivo. We created dlCR2 Ren, with the same E1A CR2 deletion as dl922-947 and the luciferase gene from Renilla reniformis downstream of E1. Light emitted from s.c. and i.p. IGROV1 ovarian carcinoma xenografts was measured following treatment with dlCR2 Ren. Mice bearing s.c. IGROV1 xenografts were injected with 2.96 to 3.7 MBq of [18F]FLT 48 and 168 hours following i.t. injection of dl922-947 or control virus Ad LM-X. The presence of Renilla luciferase in dlCR2 Ren did not reduce in vitro nor in vivo potency compared with dl922-947. Light emission correlated closely with E1A expression in vitro and peaked 48 hours after dlCR2 Ren injection in both s.c. and i.p. IGROV1 xenografts. It diminished by 168 hours in s.c. tumors but persisted for at least 2 weeks in i.p. models. Normalized tumor [18F]FLT uptake at 60 minutes (NUV60), fractional retention, and area under radioactivity curve all decreased marginally 48 hours after dl922-947 treatment and significantly at 168 hours compared with controls. There was a close linear correlation between NUV60 and both tumor proliferation (Ki67 labeling index) and thymidine kinase 1 expression. Renilla luciferase bioluminescence and [18F]FLT-PET imaging are capable of quantifying the activity and effectiveness of E1A CR2-deleted adenoviral mutants in ovarian cancer. PMID:16982761

Leyton, Julius; Lockley, Michelle; Aerts, Joeri L; Baird, Sarah K; Aboagye, Eric O; Lemoine, Nicholas R; McNeish, Iain A

2006-09-15

127

Use of bioluminescent Escherichia coli O157:H7 to study intra-protozoan survival of bacteria within Tetrahymena pyriformis.  

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A method was developed that enabled real-time monitoring of the uptake and survival of bioluminescent Escherichia coli O157 within the freshwater ciliate Tetrahymena pyriformis. Constitutively bioluminescent E. coli O157 pLITE27 was cocultured with T. pyriformis in nutrient-deficient (Chalkley's) and in nutrient-rich (proteose peptone, yeast extract) media. Non-internalised bacteria were inactivated by addition of colistin, indicated by a decline in bioluminescence. Protozoa were subsequently lysed with Triton X-100 which lead to a further drop in bioluminescence, consistent with release of live internal bacteria from T. pyriformis into the colistin-containing environment. Bioluminescence measurements for non-lysed cultures indicated that internalised E. coli O157 pLITE27 cells were only slowly digested by T. pyriformis, in both media, over the time period studied. The results suggest that bioluminescent bacteria are useful tools in the study of bacterial intra-protozoan survival. PMID:12799006

Nelson, Shona M; Cooper, Alison A A; Taylor, Elaine L; Salisbury, Vyvyan C

2003-06-01

128

Effect of irradiation on bioluminescence spectrum of microbial ATP  

International Nuclear Information System (INIS)

The effect of irradiation on bioluminescence spectrum of dehydrated cabbage microbial ATP was studied. The results showed that the spectral bandwidth of ATP standard was from 490 to 640 nm and the peak wavelength was at 563 nm. The spectral bandwidths of irradiated dehydrated cabbage microbial ATP and CK did not change. Peak wavelengths of dehydrated cabbage irradiated at different dosages were not significantly different from that of CK. The peaks of bioluminescence spectrum of irradiated samples were higher than that of CK, which may be because of the increasing concentration of ATP, and this effect would be kept for quite a long time after irradiation. (authors)

129

Modulation of firefly luciferase bioluminescence at bioelectrochemical interfaces.  

Science.gov (United States)

This paper describes a method by which the activity of an immobilized enzyme can be modulated electrochemically at an electrode. The particular example studied, involving the enzyme firefly luciferase being immobilized in a gelatin film of thickness bioluminescent emission. Using this biointerfacial arrangement, we have been able to demonstrate the reversible switching off and on of the enzyme's activity. Through a series of mechanistic studies, we have been able to determine that the bioluminescence response is modulated (on long time scales) as a consequence of the electrochemical depletion of protons at the electrode interface resulting in a local increase in pH. PMID:21651254

Chittock, R S; Glidle, A; Wharton, C W; Berovic, N; Beynon, T D; Cooper, J M

1998-10-01

130

Fast-position and time-sensitive readout of image intensifiers for single-photon detection  

Science.gov (United States)

We present results on novel image intensifier tubes for single photon detection. We have adopted an image charge coupling technique that allows a read-out of image intensifiers with good imaging properties and much superior time resolution than obtainable with the standard phosphor screen read-out. Although combinations of sealed microchannel plate detector tubes with position and time sensitive anode structures have already been reported, our method has the advantage that the superficial electrode array has not be implemented inside the tube. We couple the image charge from a high-resistive anode layer through the vacuum housing to a wedge-and-strip or delay-line pattern that can be attached from outside. We show results on single photon imaging with special intensifiers produced by Proxitronic GmbH in the visible and UV for an active diameter of 25 mm. The variability of the system, especially a version with a solar-blind UV-cathode and 40 mm active diameter, should open great opportunities for detection task in various fields like astronomy, reconnaissance, bioluminescence, atomic physics, and material research, particularly when both good imaging and timing performance are required.

Jagutzki, Ottmar; Barnstedt, Juergen; Spillmann, Uwe; Spielberger, Lutz; Mergel, Volker; Ullmann-Pfleger, Klaus; Grewing, Michael; Schmidt-Boecking, Horst W.

1999-11-01

131

A generalized hybrid algorithm for bioluminescence tomography.  

Science.gov (United States)

Bioluminescence tomography (BLT) is a promising optical molecular imaging technique on the frontier of biomedical optics. In this paper, a generalized hybrid algorithm has been proposed based on the graph cuts algorithm and gradient-based algorithms. The graph cuts algorithm is adopted to estimate a reliable source support without prior knowledge, and different gradient-based algorithms are sequentially used to acquire an accurate and fine source distribution according to the reconstruction status. Furthermore, multilevel meshes for the internal sources are used to speed up the computation and improve the accuracy of reconstruction. Numerical simulations have been performed to validate this proposed algorithm and demonstrate its high performance in the multi-source situation even if the detection noises, optical property errors and phantom structure errors are involved in the forward imaging. PMID:23667787

Shi, Shengkun; Mao, Heng

2013-05-01

132

Generation of topically transgenic rats by in utero electroporation and in vivo bioluminescence screening.  

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In utero electroporation (IUE) is a technique which allows genetic modification of cells in the brain for investigating neuronal development. So far, the use of IUE for investigating behavior or neuropathology in the adult brain has been limited by insufficient methods for monitoring of IUE transfection success by non-invasive techniques in postnatal animals. For the present study, E16 rats were used for IUE. After intraventricular injection of the nucleic acids into the embryos, positioning of the tweezer electrodes was critical for targeting either the developing cortex or the hippocampus. Ventricular co-injection and electroporation of a luciferase gene allowed monitoring of the transfected cells postnatally after intraperitoneal luciferin injection in the anesthetized live P7 pup by in vivo bioluminescence, using an IVIS Spectrum device with 3D quantification software. Area definition by bioluminescence could clearly differentiate between cortical and hippocampal electroporations and detect a signal longitudinally over time up to 5 weeks after birth. This imaging technique allowed us to select pups with a sufficient number of transfected cells assumed necessary for triggering biological effects and, subsequently, to perform behavioral investigations at 3 month of age. As an example, this study demonstrates that IUE with the human full length DISC1 gene into the rat cortex led to amphetamine hypersensitivity. Co-transfected GFP could be detected in neurons by post mortem fluorescence microscopy in cryosections indicating gene expression present at ?6 months after birth. We conclude that postnatal bioluminescence imaging allows evaluating the success of transient transfections with IUE in rats. Investigations on the influence of topical gene manipulations during neurodevelopment on the adult brain and its connectivity are greatly facilitated. For many scientific questions, this technique can supplement or even replace the use of transgenic rats and provide a novel technology for behavioral neuroscience. PMID:24084570

Vomund, Sandra; Sapir, Tamar; Reiner, Orly; Silva, Maria A de Souza; Korth, Carsten

2013-01-01

133

Real-time metabolic imaging  

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The endogenous substance pyruvate is of major importance to maintain energy homeostasis in the cells and provides a window to several important metabolic processes essential to cell survival. Cell viability is therefore reflected in the metabolism of pyruvate. NMR spectroscopy has until now been the only noninvasive method to gain insight into the fate of pyruvate in the body, but the low NMR sensitivity even at high field strength has only allowed information about steady-state conditions. The medically relevant information about the distribution, localization, and metabolic rate of the substance during the first minute after the injection has not been obtainable. Use of a hyperpolarization technique has enabled 10-15% polarization of 13C1 in up to a 0.3 M pyruvate solution. i.v. injection of the solution into rats and pigs allows imaging of the distribution of pyruvate and mapping of its major metabolites lactate and alanine within a time frame of 10 s. Real-time molecular imaging with MRI has become a reality. 13C | dynamic nuclear polarization | hyperpolarized | MRI | spectroscopy

Golman, Klaes; in 't Zandt, René; Thaning, Mikkel

2006-07-01

134

Photodynamic inactivation of recombinant bioluminescent Escherichia coli by cationic porphyrins under artificial and solar irradiation.  

Science.gov (United States)

A faster and simpler method to monitor the photoinactivation process of Escherichia coli involving the use of recombinant bioluminescent bacteria is described here. Escherichia coli cells were transformed with luxCDABE genes from the marine bioluminescent bacterium Vibrio fischeri and the recombinant bioluminescent indicator strain was used to assess, in real time, the effect of three cationic meso-substituted porphyrin derivatives on their metabolic activity, under artificial (40 W m(-2)) and solar irradiation (approximately 620 W m(-2)). The photoinactivation of bioluminescent E. coli is effective (>4 log bioluminescence decrease) with the three porphyrins used, the tricationic porphyrin Tri-Py+-Me-PF being the most efficient compound. The photoinactivation process is efficient both with solar and artificial light, for the three porphyrins tested. The results show that bioluminescence analysis is an efficient and sensitive approach being, in addition, more affordable, faster, cheaper and much less laborious than conventional methods. This approach can be used as a screening method for bacterial photoinactivation studies in vitro and also for the monitoring of the efficiency of novel photosensitizer molecules. As far as we know, this is the first study involving the use of bioluminescent bacteria to monitor the antibacterial activity of porphyrins under environmental conditions. PMID:18712538

Alves, Eliana; Carvalho, Carla M B; Tomé, João P C; Faustino, Maria A F; Neves, Maria G P M S; Tomé, Augusto C; Cavaleiro, José A S; Cunha, Angela; Mendo, Sónia; Almeida, Adelaide

2008-11-01

135

A gantry-based tri-modality system for bioluminescence tomography  

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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.

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

2012-04-01

136

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

137

Bioluminescent high-throughput assay for the bacteria adherence to the tissue culture cells.  

Science.gov (United States)

The goal of this study was develop a rapid high-throughput method for the assessment of the bacterial adhesion to tissue culture cells and test this method by investigation of the adhesion and growth of pathogenic and non-pathogenic Escherichia coli strains in the presence of HeLa human epithelial cells. Fifteen strains of E. coli were transformed with a plasmid carrying the entire lux operon of Photorhabdus luminescens to make them bioluminescent. By using the Time-to-Detection approach and bioluminescence imaging in microplate format, the adherence and growth of bacteria in tissue culture medium in the presence of HeLa cells was monitored. It was observed that Eagle's minimal essential medium (EMEM) supplemented with 10% fetal bovine serum (FBS) significantly inhibited growth of E. coli. However, in the presence of HeLa cells the detected growth of E. coli was similar to the growth observed in LB medium. It was established that the initial number of E. coli cells present in the microplate directly correlated with the time necessary for the bioluminescence signal to reach the threshold level, hence allowing the accurate assessment of the adhered cells within 8-10 h. Neither bacterial adherence nor growth kinetics correlated with the pathogenicity of the strain though they were strain-specific. The developed approach provided new information on the interaction of E. coli with epithelial cells and could be used for both pathogenicity research and for the screening of potential therapeutic agents for the ability to minimize pathogen colonization of human tissues. PMID:21337328

Brovko, L; Minikh, O; Piekna, A; Griffiths, M W

2011-07-01

138

Synthesis and bioluminescence of difluoroluciferin.  

Science.gov (United States)

A new synthesis route to firefly luciferin analogs was developed via the synthesis of 5',7'-difluoroluciferin. As a luciferase substrate, it produces maximal bioluminescence at a much lower pH than is optimal for native luciferin, and at lower pH it gives much more of the red-shifted emission that is characteristic of the phenolate. These features are attributed to the enhanced acidity of the o,o-difluorophenol. PMID:25239851

Pirrung, Michael C; Biswas, Goutam; De Howitt, Natalie; Liao, Jiayu

2014-10-15

139

Mathematical Study and Numerical Simulation of Multispectral Bioluminescence Tomography  

Directory of Open Access Journals (Sweden)

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

Ge Wang

2006-12-01

140

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.

 
 
 
 
141

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.

Knight, J. D.; Sky, Sea A.

142

REVIEW OF ENVIRONMENTAL APPLICATIONS OF BIOLUMINESCENCE MEASUREMENTS  

Science.gov (United States)

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

143

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

144

Bacterial bioluminescence and Gumbel statistics: From quorum sensing to correlation  

Science.gov (United States)

We show that, in particular experimental conditions, the time course of the radiant fluxes, measured from a bioluminescent emission of a Vibrio harveyi related strain, collapse after suitable rescaling onto the Gumbel distribution of extreme value theory. We argue that the activation times of the strain luminous emission follow the universal behavior described by this statistical law, in spite of the fact that no extremal process is known to occur.

Delle Side, Domenico; Velardi, Luciano; Nassisi, Vincenzo; Pennetta, Cecilia; Alifano, Pietro; Talà, Adelfia; Salvatore Tredici, Maurizio

2013-12-01

145

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

146

Zero-scan-time vascular MR imaging  

International Nuclear Information System (INIS)

This paper describes a method that integrates vascular imaging with a routine high-resolution MR imaging examination in the same acquisition. All studies are performed after injection of Gd-DTPA using gradient recalled acquisition in a steady state with RF spoiling. Half-echo processing is used to reduce the echo time to 5 msec. Vascular images were extracted from the routinely acquired imaging examinations in 15 patients. High-quality basic images optimized for gadolinium-enhanced routine diagnostic MR imaging also provide suitable vascular enhancement for MR angiography in all cases

147

Image Acquisition in Real Time  

Science.gov (United States)

In 1995, Carlos Jorquera left NASA s Jet Propulsion Laboratory (JPL) to focus on erasing the growing void between high-performance cameras and the requisite software to capture and process the resulting digital images. Since his departure from NASA, Jorquera s efforts have not only satisfied the private industry's cravings for faster, more flexible, and more favorable software applications, but have blossomed into a successful entrepreneurship that is making its mark with improvements in fields such as medicine, weather forecasting, and X-ray inspection. Formerly a JPL engineer who constructed imaging systems for spacecraft and ground-based astronomy projects, Jorquera is the founder and president of the three-person firm, Boulder Imaging Inc., based in Louisville, Colorado. Joining Jorquera to round out the Boulder Imaging staff are Chief Operations Engineer Susan Downey, who also gained experience at JPL working on space-bound projects including Galileo and the Hubble Space Telescope, and Vice President of Engineering and Machine Vision Specialist Jie Zhu Kulbida, who has extensive industrial and research and development experience within the private sector.

2003-01-01

148

In vivo quantification of fluorescent molecular markers in real-time by ratio imaging for diagnostic screening and image-guided surgery.  

Science.gov (United States)

Future applications of "molecular diagnostic screening" and "molecular image-guided surgery" will demand images of molecular markers with high resolution and high throughput (~ > or =30 frames/second). MRI, SPECT, PET, optical fluorescence tomography, hyper-spectral fluorescence imaging, and bioluminescence imaging do not offer such high frame rates. 2D optical fluorescence imaging can provide surface images with high resolution and high throughput. The ability to accurately quantify the fluorescence in vivo is critical to extract functional information of the disease state, however few methods are available. Here, a ratiometric 2D quantification method is introduced. Through mathematical modeling the performance was evaluated using optical properties that resembled biological tissues with the fluorescent marker Protoporhyrin IX. Experimentally the performance was evaluated in optical phantoms with different optical properties employing a novel prototype clinical imaging system. The clinical feasibility of real-time, image-guided surgery was demonstrated in patients undergoing prostatectomy. Discussed are the reasons why the introduced method leads to an increased quantification performance followed by modifications so it can be applied to novel fluorescent molecular markers as phthalocyanine 4 and dual-fluorescent markers. These offer additional advantages as these can provide a linear response to marker concentration and further minimize the dependence on autofluorescence and optical properties, as demonstrated through modeling. PMID:17868102

Bogaards, A; Sterenborg, H J C M; Trachtenberg, J; Wilson, B C; Lilge, L

2007-08-01

149

Multiplexing bioluminescent and fluorescent reporters to monitor live cells.  

Science.gov (United States)

Reporter proteins are valuable tools to monitor promoter activities and characterize signal transduction pathways. Many of the currently available promoter reporters have drawbacks that compromise their performance. Enzyme-based reporter systems using cytosolic luciferases are highly sensitive, but require a cell lysis step that prevents their use in long-term monitoring. By contrast, secreted bioluminescent reporters like Metridia luciferase and Secreted Alkaline Phosphatase can be assayed repeatedly, using supernatant from the same live cell population to produce many sets of data over time. This is crucial for studies with limited amounts of cells, as in the case of stem cells. The use of secreted bioluminescent reporters also enables broader applications to provide more detailed information using live cells; for example, multiplexing with fluorescent proteins. Here, data is presented describing the characteristics of secreted Metridia luciferase and its use in multiplexing applications with either Secreted Alkaline Phosphatase or a fluorescent protein. PMID:20161823

Haugwitz, Michael; Nourzaie, Omar; Garachtchenko, Tatiana; Hu, Lanrong; Gandlur, Suvarna; Olsen, Cathy; Farmer, Andrew; Chaga, Grigoriy; Sagawa, Hiroaki

2008-01-01

150

Three-dimensional multi bioluminescent sources reconstruction based on adaptive finite element method  

Science.gov (United States)

Among many optical molecular imaging modalities, bioluminescence imaging (BLI) has more and more wide application in tumor detection and evaluation of pharmacodynamics, toxicity, pharmacokinetics because of its noninvasive molecular and cellular level detection ability, high sensitivity and low cost in comparison with other imaging technologies. However, BLI can not present the accurate location and intensity of the inner bioluminescence sources such as in the bone, liver or lung etc. Bioluminescent tomography (BLT) shows its advantage in determining the bioluminescence source distribution inside a small animal or phantom. Considering the deficiency of two-dimensional imaging modality, we developed three-dimensional tomography to reconstruct the information of the bioluminescence source distribution in transgenic mOC-Luc mice bone with the boundary measured data. In this paper, to study the osteocalcin (OC) accumulation in transgenic mOC-Luc mice bone, a BLT reconstruction method based on multilevel adaptive finite element (FEM) algorithm was used for localizing and quantifying multi bioluminescence sources. Optical and anatomical information of the tissues are incorporated as a priori knowledge in this method, which can reduce the ill-posedness of BLT. The data was acquired by the dual modality BLT and Micro CT prototype system that was developed by us. Through temperature control and absolute intensity calibration, a relative accurate intensity can be calculated. The location of the OC accumulation was reconstructed, which was coherent with the principle of bone differentiation. This result also was testified by ex vivo experiment in the black 96-plate well using the BLI system and the chemiluminescence apparatus.

Ma, Xibo; Tian, Jie; Zhang, Bo; Zhang, Xing; Xue, Zhenwen; Dong, Di; Han, Dong

2011-03-01

151

An adaptive regularization parameter choice strategy for multispectral bioluminescence tomography  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Bioluminescence tomography (BLT) provides an effective tool for monitoring physiological and pathological activities in vivo. However, the measured data in bioluminescence imaging are corrupted by noise. Therefore, regularization methods are commonly used to find a regularized solution. Nevertheless, for the quality of the reconstructed bioluminescent source obtained by regularization methods, the choice of the regularization parameters is crucial. To date, the selection of regularization parameters remains challenging. With regards to the above problems, the authors proposed a BLT reconstruction algorithm with an adaptive parameter choice rule. Methods: The proposed reconstruction algorithm uses a diffusion equation for modeling the bioluminescent photon transport. The diffusion equation is solved with a finite element method. Computed tomography (CT) images provide anatomical information regarding the geometry of the small animal and its internal organs. To reduce the ill-posedness of BLT, spectral information and the optimal permissible source region are employed. Then, the relationship between the unknown source distribution and multiview and multispectral boundary measurements is established based on the finite element method and the optimal permissible source region. Since the measured data are noisy, the BLT reconstruction is formulated as l{sub 2} data fidelity and a general regularization term. When choosing the regularization parameters for BLT, an efficient model function approach is proposed, which does not require knowledge of the noise level. This approach only requests the computation of the residual and regularized solution norm. With this knowledge, we construct the model function to approximate the objective function, and the regularization parameter is updated iteratively. Results: First, the micro-CT based mouse phantom was used for simulation verification. Simulation experiments were used to illustrate why multispectral data were used rather than monochromatic data. Furthermore, the study conducted using an adaptive regularization parameter demonstrated our ability to accurately localize the bioluminescent source. With the adaptively estimated regularization parameter, the reconstructed center position of the source was (20.37, 31.05, 12.95) mm, and the distance to the real source was 0.63 mm. The results of the dual-source experiments further showed that our algorithm could localize the bioluminescent sources accurately. The authors then presented experimental evidence that the proposed algorithm exhibited its calculated efficiency over the heuristic method. The effectiveness of the new algorithm was also confirmed by comparing it with the L-curve method. Furthermore, various initial speculations regarding the regularization parameter were used to illustrate the convergence of our algorithm. Finally, in vivo mouse experiment further illustrates the effectiveness of the proposed algorithm. Conclusions: Utilizing numerical, physical phantom and in vivo examples, we demonstrated that the bioluminescent sources could be reconstructed accurately with automatic regularization parameters. The proposed algorithm exhibited superior performance than both the heuristic regularization parameter choice method and L-curve method based on the computational speed and localization error.

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

2011-11-15

152

Time Variant Change Analysis in Satellite Images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 a...

Rachita Sharma; Sanjay Kumar Dubey

2013-01-01

153

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

154

Multiplexed mAbs: a new strategy in preclinical time-domain imaging of acute myeloid leukemia.  

Science.gov (United States)

Antibodies play a fundamental role in diagnostic immunophenotyping of leukemias and in cell-targeting therapy. However, this versatility is not reflected in imaging diagnostics. In the present study, we labeled anti–human mAbs monochromatically against selected human myeloid markers expressed on acute myeloid leukemia (AML) cells, all with the same near-infrared fluorochrome. In a novel “multiplexing” strategy, we then combined these mAbs to overcome the limiting target-to-background ratio to image multiple xenografts of AML. Time-domain imaging was used to discriminate autofluorescence from the distinct fluorophore-conjugated antibodies. Imaging with multiplexed mAbs demonstrated superior imaging of AML to green fluorescent protein or bioluminescence and permitted evaluation of therapeutic efficacy with the standard combination of anthracycline and cytarabine in primary patient xenografts. Multiplexing mAbs against CD11b and CD11c provided surrogate imaging biomarkers of differentiation therapy in an acute promyelocytic leukemia model treated with all-trans retinoic acid combined with the histone-deacetylase inhibitor valproic acid. We present herein an optimizedapplication of multiplexed immunolabeling in vivo for optical imaging of AML cellxenografts that provides reproducible, highly accurate disease staging and monitoring of therapeutic effects. PMID:23243270

McCormack, Emmet; Muji?, Maja; Osdal, Tereza; Bruserud, Øystein; Gjertsen, Bjørn Tore

2013-02-14

155

NanoLuc Reporter for Dual Luciferase Imaging in Living Animals  

Science.gov (United States)

Bioluminescence imaging is utilized widely for cell-based assays and animal imaging studies in biomedical research and drug development, capitalizing on high signal-to-background of this technique. A relatively small number of luciferases are available for imaging studies, substantially limiting the ability to image multiple molecular and cellular events as done commonly with fluorescence imaging. To advance dual reporter bioluminescence molecular imaging, we tested a recently developed, ATP-independent luciferase enzyme from Oplophorus gracilirostris (NanoLuc, NL) as a reporter for animal imaging. We demonstrated that NL could be imaged in superficial and deep tissues in living mice, although detection of NL in deep tissues was limited by emission of predominantly blue light by this enzyme. Changes in bioluminescence from NL over time could be used to quantify tumor growth, and secreted NL was detectable in small volumes of serum. We combined NL and firefly luciferase reporters to quantify two key steps in TGF-? signaling in intact cells and living mice, establishing a novel dual luciferase imaging strategy for quantifying signal transduction and drug targeting. Our results establish NL as new reporter for bioluminescence imaging studies in intact cells and living mice that will expand imaging of signal transduction in normal physiology, disease, and drug development. PMID:24371848

Stacer, Amanda C.; Nyati, Shyam; Moudgil, Pranav; Iyengar, Rahul; Luker, Kathryn E.; Rehemtulla, Alnawaz; Luker, Gary D.

2014-01-01

156

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

157

Relationship between ultra-weak bioluminescence and vigour or irradiation dose of irradiated wheat.  

Science.gov (United States)

Ultra-weak luminescent analysis is a new way to detect the irradiation dose and the vigour of irradiated wheat. Wheat grain and wheat flour were used in this research for ultra-weak luminescent analysis. The experimental data showed that the bioluminescence intensity of wheat grain sample was different with increasing storage time and increasing dose, and a similar trend appeared in the germination rates of irradiated wheat grain. It was found that the differences in bioluminescence intensities and germination rates of irradiated wheat grain at different doses and storage times were due to the effect of irraditation on the wheat embryo and self-repair during storage. As a result, ultra-weak luminescent analysis cannot be used to detect the irradiation dose of irradiated wheat, but it can be used to determine vigour. Experiments showed that the irradiation dose had a highly significant effect on the bioluminescence intensities of wheat flour when cane sugar was added. PMID:19291806

Wang, Jun; Yu, Yong

2009-01-01

158

Can compression reduce forensic image time?  

Directory of Open Access Journals (Sweden)

Full Text Available Creating a forensic copy (image of a hard disk drive is one of the fundamental tasks a computer forensic analyst must perform. Time is often critical, and there is a need to consider a trade-off between a number of factors to achieve best results. This paper reports the results from an exploratory study into the impact of using disk drive compression on the time needed to image (and verify a hard disk drive. It was found that time reduction may be achieved once the trade-off of contributing variables was properly estimated. The findings led the investigators to suggest a step-by-step decision making process for analysts when considering disk compression as a means for reducing total image processing time.

Jon Pearse

2011-07-01

159

Doubling time of liver metastase images  

International Nuclear Information System (INIS)

For our study, where clinical and scintigraphic observation seldom lasts more than two years and where measurable metastases always exceed 1 cm3, the exponential model was adopted and our results were all calculated with GERSTENBERG's formula which gives an apparent doubling time. The liver metastases were measured on the scintigraphic image obtained, a more or less sharply limited blank which makes for a first difficulty of judgement. Two magnascanner V type PICKER 5-inch crystal scintigraphs were used, giving three images simultaneously by a transcriber made up of a stylus and a light spot built into the detection system. The isotope used is colloidal gold (198Au) phagocytized by the Kuepfferian reticulo-endothelial system. The doubling time for liver metastase scintigraphic images calculated for fifteen patients having undergone one or more isotopic checks after a first metastase image was discovered range from 10 to 103 days

160

Real Time Speckle Image De-Noising  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper presents real time speckle de-noising based on activity computation algorithm and wavelet transform. Speckles arise in an image when laser light is reflected from an illuminated surface. The process involves detection of speckles in an image by obtaining a number of frames of the same object under different illumination or angle and comparing the frames for the granular computation and de-noising the same on presence of greater activity index. The project can be im...

Kumar, D. Sachin; Seshadri, P. R.; Vaishnav, N.; Janaki, Dr Saraswathi

2014-01-01

 
 
 
 
161

Real-time neutron radiography imaging system  

Science.gov (United States)

This paper describes preliminary work on a real-time neutron radiography imaging system. Initially, the system provided neutron radiographs on photographic film using a gadolinium foil converter. The photos were digitized by a flat scanner. The system implements digital image processing functions for: counting and sizing, measurement, analysis, enhancement, geometric operations and scripting. After the development of these functions, experiments were done on the real-time imaging system and the functions were applied on images captured by a CCD camera. This is pioneer work related to neutron radiography in Brazil. This project is particularly original because our nuclear reactor has unique features: its core lies in a 6 m pool and the neutrons must be driven to the surface by a pipe. Another challenge of this project is the elimination of any light intensifier between the converter screen and the CCD camera. Neutron converter deficiencies have been compensated by applying digital image techniques to the neutron images. A low cost system has been achieved by exploring the benefits of digital image processing. Initial results provided by this system have encouraged us to continue the research and to enlarge its capability.

Dias, Ailton F.; de Albuquerque Araujo, Arnaldo

1994-05-01

162

Time-encoded imaging of energetic radiation  

Science.gov (United States)

Time-encoded imaging (TEI) is a new approach to directional detection of energetic radiation that produces images by inducing a time-dependent modulation of detected particles. TEI-based detectors use single-scatter events and have a low channel count, reducing complexity and cost while maintaining high efficiency with respect to other radiation imaging techniques such as double-scatter or coded aperture imaging. The scalability of TEI systems makes them a very promising detector class for weak source detection. Extension of the technique to high-resolution imaging is also under study. With a prototype time-encoding detector, we demonstrated detection of a neutron source at 60 m with neutron output equivalent to an IAEA significant quantity of WGPu. We have since designed and built a full-scale detector based on the time-encoding concept. We will present results from characterization of very large liquid scintillator cells, including pulse shape discrimination, as well as from studies of the detector system performance in weak source detection scenarios.

Brennan, James; Brubaker, Erik; Gerling, Mark; Marleau, Peter; Nowack, Aaron; Schuster, Patricia

2013-09-01

163

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

Directory of Open Access Journals (Sweden)

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

Wenxiang Cong

2006-12-01

164

Eco-evo bioluminescence on land and in the sea.  

Science.gov (United States)

This review discusses the evolution of bioluminescence organisms that inhabit various environments based on the current understanding of their unique ecologies and biochemistries. As shown here, however, there are still many unanswered questions regarding the functions and mechanisms of bioluminescence, which should be investigated in further studies. To facilitate future research in this field, we introduce our recent attempt, the bioluminescent organism DNA barcode initiative. This genetic reference library will provide resources for other scientists to efficiently identify unstudied bioluminescent organisms, focus their biochemical and genetic research goals, and will generally promote bioluminescence as a field of scientific study. PMID:25084993

Oba, Yuichi; Schultz, Darrin T

2014-01-01

165

Optical biosensor for environmental on-line monitoring of naphthalene and salicylate bioavailability with an immobilized bioluminescent catabolic reporter bacterium.  

Science.gov (United States)

An optical whole-cell biosensor based on a genetically engineered bioluminescent catabolic reporter bacterium was developed for continuous on-line monitoring of naphthalene and salicylate bioavailability and microbial catabolic activity potential in waste streams. The bioluminescent reporter bacterium, Pseudomonas fluorescens HK44, carries a transcriptional nahG-luxCDABE fusion for naphthalene and salicylate catabolism. Exposure to either compound resulted in inducible bioluminescence. The reporter culture was immobilized onto the surface of an optical light guide by using strontium alginate. This biosensor probe was then inserted into a measurement cell which simultaneously received the waste stream solution and a maintenance medium. Exposure under defined conditions to both naphthalene and salicylate resulted in a rapid increase in bioluminescence. The magnitude of the response and the response time were concentration dependent. Good reproducibility of the response was observed during repetitive perturbations with either naphthalene or salicylate. Exposure to other compounds, such as glucose and complex nutrient medium or toluene, resulted in either minor bioluminescence increases after significantly longer response times compared with naphthalene or no response, respectively. The environmental utility of the biosensor was tested by using real pollutant mixtures. A specific bioluminescence response was obtained after exposure to either an aqueous solution saturated with JP-4 jet fuel or an aqueous leachate from a manufactured-gas plant soil, since naphthalene was present in both pollutant mixtures. PMID:8017932

Heitzer, A; Malachowsky, K; Thonnard, J E; Bienkowski, P R; White, D C; Sayler, G S

1994-05-01

166

Optical biosensor for environmental on-line monitoring of naphthalene and salicylate bioavailability with an immobilized bioluminescent catabolic reporter bacterium  

Energy Technology Data Exchange (ETDEWEB)

An optical whole-cell biosensor based on a genetically engineered bioluminescent catabolic reporter bacterium was developed for continuous on-line monitoring of naphthalene and salicylate bioavailability and microbial catabolic activity potential in waste streams. The bioluminescent reporter bacterium, Pseudomonas fluorescens HK44, carries a transcriptional nahG-luxCDABE fusion for naphthalene and salicylate catabolism. Exposure to either compound resulted in inducible bioluminescence. The reporter culture was immobilized onto the surface of an optical guide by using strontium alginate. The biosensor probe was then inserted into a measurement cell which simultaneously received the waste stream solution and a maintenance medium. Exposure under defined conditions to both naphthalene and salicylate resulted in a rapid increase in bioluminescence. The magnitude of the response and the response time were concentration dependent. Good reproducibility of the response was observed during repetitive perturbations with either napthalene or salicylate. Exposure to other compounds, such as glucose and complex nutrient medium or toluene, resulted in either minor bioluminescence increases after significantly longer response times compared with naphthalene or no response, respectively. The environmental utility of the biosensor was tested by using real pollutant mixtures. A specific bioluminescence response was obtained after exposure to either an aqueous solution saturated with JP-4 fuel or an aqueous leachate from a manufactured-gas plant soil, since napthalene was present in both pollutant mixtures. 43 refs., 4 figs., 1 tab.

Heitzer, A.; Malachowsky, K.; Thonnard, J.E. [Univ. of Tennessee, Knoxville, TN (United States)] [and others

1994-05-01

167

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

168

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.

169

A review of the measurement and modelling of dinoflagellate bioluminescence  

Science.gov (United States)

Bioluminescence is a striking phenomenon that is ubiquitous throughout the world's oceans. Here we bring together the findings of in situ observations of bioluminescence in the upper ocean (bioluminescence within the upper ocean, as well as its relationships with other environmental parameters. As dinoflagellates are often the dominant source of stimulated bioluminescence in the upper ocean we review current knowledge regarding the bioluminescence of these organisms including its potential ecological function. Modelling and prediction of the bioluminescent field has previously had only limited success, especially over timescales greater than a few days. We suggest that the potential exists to improve the forecasting of upper ocean bioluminescence potential on longer, seasonal, timescales by utilising and improving methods to model dinoflagellates.

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

2013-02-01

170

A Multi-Camera System for Bioluminescence Tomography in Preclinical Oncology Research  

Directory of Open Access Journals (Sweden)

Full Text Available Bioluminescent imaging (BLI of cells expressing luciferase is a valuable noninvasive technique for investigating molecular events and tumor dynamics in the living animal. Current usage is often limited to planar imaging, but tomographic imaging can enhance the usefulness of this technique in quantitative biomedical studies by allowing accurate determination of tumor size and attribution of the emitted light to a specific organ or tissue. Bioluminescence tomography based on a single camera with source rotation or mirrors to provide additional views has previously been reported. We report here in vivo studies using a novel approach with multiple rotating cameras that, when combined with image reconstruction software, provides the desired representation of point source metastases and other small lesions. Comparison with MRI validated the ability to detect lung tumor colonization in mouse lung.

Ralph P. Mason

2013-07-01

171

Cloaking and imaging at the same time  

Science.gov (United States)

In this letter, we propose a conceptual device to perform good imaging with positive refraction. At the same time, this device is an isotropic omnidirectional cloak with a perfect electric conductor hiding region and shows versatile illusion optical effects. Numerical simulations are performed to verify the functionalities.

Wu, Qiannan; Xu, Yadong; Li, Hui; Chen, Huanyang

2013-02-01

172

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

173

Bioluminescence: from chemical bonds to photons.  

Science.gov (United States)

The biological transformation of chemical to photic energy involves an enzyme-mediated chemiluminescent reaction, in which one of the products exists in an electronically excited state, emitting a photon as it returns to the ground state. The colour of bioluminescence differs in different organisms, ranging from the deep blue (460 nm) of certain crustacea, through the bluish green (490 nm) of some bacteria, the green (530 nm) of mushrooms to the red (about 600 nm) of the railroad worm. In one case, energy transfer has been demonstrated from the enzyme system to material that emits light with a longer wavelength. The energies involved range from about 165 to 250 kJ/einstein (40 to 60 kcal/einstein). Boyle first showed that air was involved in bioluminescence in 1668 in his experiments with an air pump. Over the past 100 years, it has become clear that most if not all bioluminescent systems require molecular oxygen. The recent isolation and characterization of an oxygen-containing (peroxide) enzyme intermediate from the bacterial system is described and a reaction mechanism is postulated. This scheme is compared with other hypothetical mechanisms, in particular those involving a four-membered ring intermediate, a dioxetane, in which the simultaneous cleavage of two bonds leaves one product in an excited state. I shall discuss the special role of luciferases in bioluminescence, especially in flashing mechanisms involving 'precharged' intermediates. PMID:238805

Hastings, J W

1975-01-01

174

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

175

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

176

Real-Time Imaging of Quantum Entanglement  

CERN Document Server

Quantum Entanglement - correlations between at least two systems that are stronger than classically explainable - is widely regarded as one of the most prominent features of quantum mechanics and quantum information science. Although, the creation of entanglement between two systems has become possible in laboratories, it has been out of the grasp of one of the most natural ways to investigate nature: direct visual observation. Here we show that modern imaging technology, namely a triggered intensified charge coupled device (ICCD) camera, is fast and sensitive enough to image in real-time the influence of the measurement of one photon on its entangled partner. To demonstrate the non-classicality of the measurements quantitatively from the registered intensity we develop a novel method to statistically analyze the image and precisely quantify the number of photons within a certain region. In addition, we show the high flexibility of our experimental setup in creating any desired spatial-mode entanglement, even...

Fickler, Robert; Lapkiewicz, Radek; Ramelow, Sven; Zeilinger, Anton

2013-01-01

177

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

178

High energy real-time imaging studies  

Energy Technology Data Exchange (ETDEWEB)

Performance characteristics of high energy real-time radiography (RTR) systems were optimized by interchanging components and varying optical coupling methods. Phosphor screens, fiber optic scintillation plates, monolithic high density glass scintillation plates, mirror coatings, different cameras and integration times were studied. X-ray sources were 4- and 9-MeV linear accelerators. High density monolithic glass, high resolution and wide dynamic range CCD cameras, and special focusing and fixturing methods have provided significantly improved spatial resolution and contrast for our high energy real-rime imaging. RTR systems with improved performance characteristics and proper translational/rotational staging were adapted for computed tomography applications.

Haskins, J.J.; Dolan, K.W.; Perkins, D.E.; Rikard, D.; Schneberk, D.J.

1993-04-01

179

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

180

Metabolic imaging in multiple time scales.  

Science.gov (United States)

We report here a novel combination of time-resolved imaging methods for probing mitochondrial metabolism in multiple time scales at the level of single cells. By exploiting a mitochondrial membrane potential reporter fluorescence we demonstrate the single cell metabolic dynamics in time scales ranging from microseconds to seconds to minutes in response to glucose metabolism and mitochondrial perturbations in real time. Our results show that in comparison with normal human mammary epithelial cells, the breast cancer cells display significant alterations in metabolic responses at all measured time scales by single cell kinetics, fluorescence recovery after photobleaching and by scaling analysis of time-series data obtained from mitochondrial fluorescence fluctuations. Furthermore scaling analysis of time-series data in living cells with distinct mitochondrial dysfunction also revealed significant metabolic differences thereby suggesting the broader applicability (e.g. in mitochondrial myopathies and other metabolic disorders) of the proposed strategies beyond the scope of cancer metabolism. We discuss the scope of these findings in the context of developing portable, real-time metabolic measurement systems that can find applications in preclinical and clinical diagnostics. PMID:24013043

Ramanujan, V Krishnan

2014-03-15

 
 
 
 
181

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

182

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)

183

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

184

Practical enzymology course based on bioluminescence.  

Science.gov (United States)

We describe our experience with laboratory courses in enzymology based on the phenomenon of bioluminescence. The soluble and immobilized enzymes of luminous bacteria are used and the practical enzymological course consists of four main courses: (1) training in measuring the activities of soluble and immobilized enzymes; (2) the investigation of kinetic characteristics (kinetic constants) and enzyme-substrate and enzyme-inhibitor interactions in the bacterial bioluminescent reaction; (3) The testing of physico-chemical characteristics of enzymes (pH, temperature, ion strength, etc.); (4) the effect of inhibitors on enzymes. Training is possible in groups of about ten persons. Our practice work has been introduced in the biological, pedagogical and physical departments of Krasnoyarsk State University. Students of the pedagogical department have created a popular and interesting series of laboratory works for high school children aged 14-17 years. PMID:10441047

Kratasyuk, V A; Kudinova, I Y

1999-01-01

185

Understanding Bioluminescence in Dinoflagellates—How Far Have We Come?  

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

Martha Valiadi

2013-09-01

186

Rapid bioluminescence method for bacteriuria screening.  

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A study was performed to evaluate the UTIscreen (Los Alamos Diagnostics, Los Alamos, N. Mex.), a rapid bioluminescence bacteriuria screen. The UTIscreen was compared with three other rapid bacteriuria screens: the Bac-T-Screen (Vitek Systems, Hazelwood, Mo.), an automated filtration device; the Chemstrip LN (Boehringer Mannheim Diagnostics, BioDynamics, Indianapolis, Ind.), an enzyme dipstick; and the Gram stain. A semiquantitative plate culture was used as the reference method. Of the 1,000 ...

Pezzlo, M. T.; Ige, V.; Woolard, A. P.; Peterson, E. M.; La Maza, L. M.

1989-01-01

187

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

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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

188

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

189

Immobilization of bioluminescent Escherichia coli cells using natural and artificial fibers treated with polyethyleneimine.  

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Biosensors based on whole-cell bioluminescence have the potential to become a cost-effective alternative to conventional detection methods upon validation of target selectivity and sensitivity. However, quantitative analysis of bioluminescence is greatly hindered due to lack of control over the total number of cells in a suspending culture. In this study, the effect of surface properties of genetically engineered luminous E. coli cells and fibrous matrices on the immobilization capacity and effectiveness under various environmental conditions were characterized. Four different fibers, including cotton, polyester, viscose rayon, and silk, were investigated. Although cell adhesion was observed on untreated viscose and cotton fibers, viscose fiber pretreated with 0.667% polyethyleneimine (PEI) was found capable of immobilizing the most viable E. coli DPD2234 cells, followed by viscose treated with 0.33% and 1% PEI. The cells immobilized on PEI-treated viscose remained viable and yielded 20% or more bioluminescence signals immediately upon contact with the inducer up to 72 h without feeding nutrients to the cells, suggesting that viscose treated with 0.667% PEI could provide a stable immobilization mechanism for bioluminescent E. coli cells with long sensing period, quick response time, and good signal reproducibility. PMID:19285859

Chu, Yi-Fang; Hsu, Chia-Hua; Soma, Pavan K; Lo, Y Martin

2009-07-01

190

Luciferase-YFP fusion tag with enhanced emission for single-cell luminescence imaging.  

Science.gov (United States)

Taking advantage of the phenomenon of bioluminescence resonance energy transfer (BRET), we developed a bioluminescent probe composed of EYFP and Renilla reniformis luciferase (RLuc)--BRET-based autoilluminated fluorescent protein on EYFP (BAF-Y)--for near-real-time single-cell imaging. We show that BAF-Y exhibits enhanced RLuc luminescence intensity and appropriate subcellular distribution when it was fused to targeting-signal peptides or histone H2AX, thus allowing high spatial and temporal resolution microscopy of living cells. PMID:17618293

Hoshino, Hideto; Nakajima, Yoshihiro; Ohmiya, Yoshihiro

2007-08-01

191

A REVIEW OF ENVIRONMENTAL APPLICATIONS OF BIOLUMINESCENCE MEASUREMENTS  

Science.gov (United States)

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

192

Use of the liquid scintillation spectrometer in bioluminescence analysis  

International Nuclear Information System (INIS)

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

193

Evaluation of the ecotoxicity of pollutants with bioluminescent microorganisms.  

Science.gov (United States)

This chapter deals with the use of bioluminescent microorganisms in environmental monitoring, particularly in the assessment of the ecotoxicity of pollutants. Toxicity bioassays based on bioluminescent microorganisms are an interesting complement to classical toxicity assays, providing easiness of use, rapid response, mass production, and cost effectiveness. A description of the characteristics and main environmental applications in ecotoxicity testing of naturally bioluminescent microorganisms, covering bacteria and eukaryotes such as fungi and dinoglagellates, is reported in this chapter. The main features and applications of a wide variety of recombinant bioluminescent microorganisms, both prokaryotic and eukaryotic, are also summarized and critically considered. Quantitative structure-activity relationship models and hormesis are two important concepts in ecotoxicology; bioluminescent microorganisms have played a pivotal role in their development. As pollutants usually occur in complex mixtures in the environment, the use of both natural and recombinant bioluminescent microorganisms to assess mixture toxicity has been discussed. The main information has been summarized in tables, allowing quick consultation of the variety of luminescent organisms, bioluminescence gene systems, commercially available bioluminescent tests, environmental applications, and relevant references. PMID:25216953

Fernández-Piñas, Francisca; Rodea-Palomares, Ismael; Leganés, Francisco; González-Pleiter, Miguel; Angeles Muñoz-Martín, M

2014-01-01

194

Iterative reconstruction for bioluminescence tomography with total variation regularization  

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Bioluminescence tomography(BLT) is an instrumental molecular imaging modality designed for the 3D location and quantification of bioluminescent sources distribution in vivo. In our context, the diffusion approximation(DA) to radiative transfer equation(RTE) is utilized to model the forward process of light propagation. Mathematically, the solution uniqueness does not hold for DA-based BLT which is an inverse source problem of partial differential equations and hence is highly ill-posed. In the current work, we concentrate on a general regularization framework for BLT with Bregman distance as data fidelity and total variation(TV) as regularization. Two specializations of the Bregman distance, the least squares(LS) distance and Kullback-Leibler(KL) divergence, which correspond to the Gaussian and Poisson environments respectively, are demonstrated and the resulting regularization problems are denoted as LS+TV and KL+TV. Based on the constrained Landweber(CL) scheme and expectation maximization(EM) algorithm for BLT, iterative algorithms for the LS+TV and KL+TV problems in the context of BLT are developed, which are denoted as CL-TV and EM-TV respectively. They are both essentially gradient-based algorithms alternatingly performing the standard CL or EM iteration step and the TV correction step which requires the solution of a weighted ROF model. Chambolle's duality-based approach is adapted and extended to solving the weighted ROF subproblem. Numerical experiments for a 3D heterogeneous mouse phantom are carried out and preliminary results are reported to verify and evaluate the proposed algorithms. It is found that for piecewise-constant sources both CL-TV and EM-TV outperform the conventional CL and EM algorithms for BLT.

Jin, Wenma; He, Yonghong

2012-12-01

195

Dinoflagellate bioluminescence in response to mechanical stimuli in water flows  

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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

196

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

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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

197

Phase Time and Envelope Time in Time-Distance Analysis and Acoustic Imaging  

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Time-distance analysis and acoustic imaging are two related techniques to probe the local properties of solar interior. In this study, we discuss the relation of phase time and envelope time between the two techniques. The location of the envelope peak of the cross correlation function in time-distance analysis is identified as the travel time of the wave packet formed by modes with the same w/l. The phase time of the cross correlation function provides information of the phase change accumulated along the wave path, including the phase change at the boundaries of the mode cavity. The acoustic signals constructed with the technique of acoustic imaging contain both phase and intensity information. The phase of constructed signals can be studied by computing the cross correlation function between time series constructed with ingoing and outgoing waves. In this study, we use the data taken with the Taiwan Oscillation Network (TON) instrument and the Michelson Doppler Imager (MDI) instrument. The analysis is carried out for the quiet Sun. We use the relation of envelope time versus distance measured in time-distance analyses to construct the acoustic signals in acoustic imaging analyses. The phase time of the cross correlation function of constructed ingoing and outgoing time series is twice the difference between the phase time and envelope time in time-distance analyses as predicted. The envelope peak of the cross correlation function between constructed ingoing and outgoing time series is located at zero time as predicted for results of one-bounce at 3 mHz for all four data sets and two-bounce at 3 mHz for two TON data sets. But it is different from zero for other cases. The cause of the deviation of the envelope peak from zero is not known.

Chou, Dean-Yi; Duvall, Thomas L.; Sun, Ming-Tsung; Chang, Hsiang-Kuang; Jimenez, Antonio; Rabello-Soares, Maria Cristina; Ai, Guoxiang; Wang, Gwo-Ping; Goode Philip; Marquette, William; Ehgamberdiev, Shuhrat; Landenkov, Oleg

1999-01-01

198

Quenching of biotinylated aequorin bioluminescence by dye-labeled avidin conjugates: application to homogeneous bioluminescence resonance energy transfer assays.  

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[see reaction]. Avidin conjugates containing the covalently attached dyes QSY-7 and dabcyl were prepared and shown to quench the bioluminescence of biotinylated aequorin. Quenching efficiency was shown to be dependent on both the label-to-avidin ratio and the concentration of the avidin conjugate. These properties were exploited to develop a homogeneous bioluminescence resonance energy transfer (BRET) assay for biotin. PMID:11405714

Adamczyk, M; Moore, J A; Shreder, K

2001-06-14

199

Endotoxin assay by bioluminescence using mutant firefly luciferase.  

Science.gov (United States)

The Limulus reaction is an application of the defense mechanism of horseshoe crab for endotoxin detection. Endotoxin is a component of the cell wall in the outer membrane of gram-negative bacteria, and causes fever or shock when it enters the human blood stream. For endotoxin detection, gel formation or turbidity of the coagulation factor chromogen or fluorescence-modified peptide is used. However, these conventional methods have problems with regard to their measurement time or sensitivity. We recently obtained a mutant firefly luciferase that has a luminescence intensity over 10-fold higher than that of the wild type. Therefore, we developed a new endotoxin detection method that combines the Limulus reaction and bioluminescence using mutant luciferase. The new method detects 0.0005EU/ml of endotoxin within 15min. PMID:19850001

Noda, Kenichi; Goto, Hitoshi; Murakami, Yuji; Ahmed, Abo Bakr F; Kuroda, Akio

2010-02-15

200

Time reversed imaging for perturbed media  

Science.gov (United States)

In time reversed imaging a pulse is propagated through a medium, the signal is recorded, and then the time reversed signal is back-propagated through the same medium to refocus the energy at the original location of the source. The refocusing is independent of the medium if the medium is the same during back-propagation. If the speed of back-propagation differs from the speed of forward propagation, the waves refocus at a different location. For a single source and single receiver, the shift is proportional to the distance between the source and the receiver and the speed difference. If several receivers are placed along a circle to form an aperture angle, the shift in the location of the refocused pulse increases with increasing aperture angle for a given source-receiver distance and speed difference. If we analyze the problem using ray theory, an increase in the aperture angle would result in a decrease in the shift of the refocused pulse. The explanation for the shift of the refocused pulse with aperture angle is simple from a wave-front point of view.

Mehta, Kurang; Snieder, Roel

2006-03-01

 
 
 
 
201

Application of stimulating agents on the immobilized bioluminescence strain Pseudomonas putida mt-2 KG1206, preserved by deep-freezing, for the convenient biomonitoring.  

Science.gov (United States)

This study was conducted to develop methods for the application of an immobilized bioluminescence strain (KG1206), preserved by deep-freezing (DF), for the monitoring of contaminated environments. The immobilized cells, preserved by DF, required approximately 2 hr for reconstitution of their activity. A large reduction in bioluminescence was observed due to the DF process; 0.07-0.58 times that of the non deep-frozen (NDF) immobilized strain. The decreased bioluminescence activity induced by the DF process was enhanced by the stimulants, sodium lactate (SL) and KNO3. However, regardless of the inducer chemical tested, the immobilized strain modified with KNO3 consistently produced greater bioluminescence than that treated with SL, in the range of 3.0-10.7 (avg. 6.7 +/- 3.69) and 1.2-4.2 (avg. 2.4 +/- 1.47) times that of control, respectively. All KNO3 treatments of contaminated groundwater samples also resulted in an increase in bioluminescence activity, but the rate of stimulation varied for each sample. Also, no strong linear correlation was observed between the bioluminescence and the total concentration of an inducer, which may related to the complex characteristics of the environmental samples. Overall, the results demonstrated the ability of immobilized genetically engineered bacteria, preserved by DF, to measure a specific group of environmental contaminants using a stimulating agent (KNO3), suggesting the potential for its preliminary application in a field-ready bioassay. PMID:21174982

Kong, In Chul

2010-01-01

202

High-speed time domain terahertz security imaging  

Science.gov (United States)

Terahertz imaging has the potential to reveal concealed explosives; metallic and non-metallic weapons (such as ceramic, plastic or composite guns and knives); flammables; biological agents; chemical weapons and other threats hidden in packages or on personnel. Time domain terahertz imaging can be employed in reflection mode to image with sub millimeter resolution. Previously, single pixel acquisition times for THz waveforms was typically 20 Hz with time records of approx 80 picoseconds, which typically restricted imaging time to hours for areas on the order of 1 square foot, limiting the field practicality of the equipment. We describe and demonstrate advanced imagers with 100 Hz --> 320 picosecond, and 4000 Hz -- 20 picosecond waveform records. These systems have been demonstrated to image >600 pixels/second from a single channel. Such a system, combined with a 32 channel linear THz array, could image a 1 square foot area with 1 mm resolution in explosives detection image in a short period of time.

Zimdars, David; White, Jeffrey; Williamson, Steven; Stuk, G.

2005-05-01

203

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

204

Energy transfer protein in coelenterate bioluminescence  

Energy Technology Data Exchange (ETDEWEB)

Bioluminescence in the sea pansy, Renilla reniformis, a marine anthozoan coelenterate, is a complex process involving the participation of three proteins. These are: (1) the luciferin-binding protein, (2) the enzyme luciferase, and (3) the green-fluorescent protein (GFP). Luciferin-binding protein is a specific subtrate-binding protein which binds one molecule of coelenterate-type luciferin per molecule of protein and which then releases luciferin in the presence of Ca/sup 2 +/. Luciferase is the enzyme which catalyzes oxidation (by O/sub 2/) of coelenterate-type luciferin, leading to the production of CO/sub 2/ and enzyme-bound excited-state oxyluciferin. Oxyluciferin may then emit blue light by a direct de-excitation pathway or may transfer excitation energy to GFP. GFP is a noncatalytic accessory protein which accepts excitation energy from oxyluciferin, by radiationless energy transfer, and then emits green bioluminescence. In this paper the purification methods and physicochemical characteristics of GFP from R. reniformis are presented, and in the companion article luciferin-binding protein is described.

Ward, W.W.; Cormier, M.J.

1979-01-01

205

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

Science.gov (United States)

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.

Dominjon, A.; Ageron, M.; Barbier, R.; Billault, M.; Brunner, J.; Cajgfinger, T.; Calabria, P.; Chabanat, E.; Chaize, D.; Doan, Q. T.; Guérin, C.; Houlès, J.; Vagneron, L.

2012-12-01

206

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.

207

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

International Nuclear Information System (INIS)

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

208

In vivo bioluminescent tracking of mesenchymal stem cells within large hydrogel constructs.  

Science.gov (United States)

The use of multicomponent scaffolds for cell implantation has necessitated sophisticated techniques for tracking of cell survival in vivo. Bioluminescent imaging (BLI) has emerged as a noninvasive tool for evaluating the therapeutic potential of cell-based tissue engineering strategies. However, the ability to use BLI measurements to longitudinally assess large 3D cellular constructs in vivo and the effects of potential confounding factors are poorly understood. In this study, luciferase-expressing human mesenchymal stem cells (hMSCs) were delivered subcutaneously within agarose and RGD-functionalized alginate hydrogel vehicles to investigate the impact of construct composition and tissue formation on BLI signal. Results showed that alginate constructs exhibited twofold greater BLI counts than agarose constructs at comparable hMSC doses. However, each hydrogel type produced a linear correlation between BLI counts and live cell number, indicating that within a given material, relative differences in cell number could be accurately assessed at early time points. The survival efficiency of delivered hMSCs was highest for the lower cell doses embedded within alginate matrix. BLI signal remained predictive of live cell number through 1 week in vivo, although the strength of correlation decreased over time. Irrespective of hydrogel type or initial hMSC seeding dose, all constructs demonstrated a degree of vascularization and development of a fibrotic capsule after 1 week. Formation of tissue within and adjacent to the constructs was accompanied by an attenuation of BLI signal during the initial period of the image acquisition time-frame. In alginate constructs only, greater vessel volume led to a delayed rise in BLI signal following luciferin delivery. This study identified vascular and fibrotic tissue ingrowth as potential confounding variables for longitudinal BLI studies. Further investigation into the complexities of noninvasive BLI data acquisition from multicomponent constructs, following implantation and subsequent tissue formation, is warranted. PMID:24576050

Allen, Ashley B; Gazit, Zulma; Su, Susan; Stevens, Hazel Y; Guldberg, Robert E

2014-10-01

209

Is it time for cardiac innervation imaging?  

Energy Technology Data Exchange (ETDEWEB)

The autonomic nervous system plays an important role in the regulation of cardiac function and the regional distribution of cardiac nerve terminals can be visualized using scintigraphic techniques. The most commonly used tracer is iodine-123-metaiodobenzylguanidine (MIBG) but C-11-hydroxyephedrine has also been used with PET. When imaging with MIBG, the ratio of heart-to-mediastinal counts is used as an index of tracer uptake, and regional distribution is also assessed from tomographic images. The rate of clearance of the tracer can also be measured and indicates the function of the adrenergic system. Innervation imaging has been applied in patients with susceptibility to arrythmias, coronary artery disease, hypertrophic and dilated cardiomyopathy and anthracycline induced cardiotoxicity. Abnormal adrenergic innervation or function appear to exist in many pathophysiological conditions indicating that sympathetic neurons are very susceptible to damage. Abnormal findings in innervation imaging also appear to have significant prognostic value especially in patients with cardiomyopathy. Recently, it has also been shown that innervation imaging can monitor drug-induced changes in cardiac adrenergic activity. Although innervation imaging holds great promise for clinical use, the method has not received wider clinical acceptance. Larger randomized studies are required to confirm the value of innervation imaging in various specific indications.

Knuuti, J. [Turku Univ., Turku (Finland) Turku PET Center; Sipola, P. [Kuopio Univ., Kuopio (Finland)

2005-03-01

210

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

211

Time selection for ISAR imaging based on time-frequency analysis  

Science.gov (United States)

Because of target's complicated movement, conventional ISAR imaging algorithm can not meet the demands of maneuvering target imaging. On the basis of analyzing the phase model of target scatterer, a new time selection method for maneuvering target imaging is proposed. Based on adaptive optimal kernel (AOK) time-frequency representation, instantaneous Doppler frequencies of echoes in range bins are estimated. According to the estimated Doppler frequencies, imaging time can be selected. Raw radar data verify the effectiveness of the proposed method.

Li, Rui; Tao, Jiang; Shi, Wang D.

2013-03-01

212

Cloaking and imaging at the same time  

CERN Document Server

In this letter, we propose a conceptual device to perform subwavelength imaging with positive refraction. The key to this proposal is that a drain is no longer a must for some cases. What's more, this device is an isotropic omnidirectional cloak with a perfect electric conductor hiding region and shows versatile illusion optical effects. Numerical simulations are performed to verify the functionalities.

Wu, Qiannan; Chen, Huanyang

2012-01-01

213

Dynamics of bioluminescence by Armillaria gallica, A. mellea and A. tabescens.  

Science.gov (United States)

Although fungal bioluminescence is well documented, the ecological significance is poorly understood. We examined bioluminescence by three sympatric species of Armillaria wood decay fungi, differing in parasitic ability. Luminescence by mycelia of four genets of A. gallica, A. mellea and A. tabescens was examined in response to environmental illumination or mechanical disturbance. Luminescence dynamics were assessed in a time series of measurements every 2 min for 72 h for mycelia growing on malt agar or on Cornus florida root wood. Luminescence by the necrotrophic species A. gallica was enhanced by environmental illumination and mechanical disturbance of mycelia. In contrast luminescence by the more parasitic A. mellea and A. tabescens was quenched by prolonged exposure to environmental illumination and less responsive to mechanical disturbance. With environmental illumination absent, all mycelia representing six genets of each Armillaria species were constitutively luminescent. The temporal dynamics of luminescence by all mycelia were complex with no evidence of the previously reported diurnal periodicity. Differences among Armillaria spp. in bioluminescence expression might reflect differences in ecological context as well. PMID:17883025

Mihail, Jeanne D; Bruhn, Johann N

2007-01-01

214

Bioluminescence as a tool for studying detoxification processes in metal salt solutions involving humic substances.  

Science.gov (United States)

The paper considers effects of humic substances (HS), as natural attenuators of toxicity, on solutions of model inorganic pollutants, metal salts - Pb(NO(3))(2), ???l(2), CuSO(4), Eu(NO(3))(3), ?r?l(3), and K(3)[Fe(?N)(6)]. Luminous bacteria Photobacterium phosphoreum and bioluminescent system of coupled enzymatic reactions were used as bioassays to monitor toxicity of salt solutions. The ability of HS to decrease or increase toxicity was demonstrated. Detoxifying concentrations of HS were determined; detoxification coefficients were calculated at different times of exposure of salt solutions to HS. To study the combined effects of HS and salts on bioluminescent assay systems, the rates of biochemical reactions and bacterial ultrastructure were analyzed. The detoxifying effects were explained by: (1) decrease of free metal content in water solutions under metal-HS binding; (2) increase of biochemical reaction rates in a bioluminescent assay system under HS effect; (3) enhancement of mucous layers on cell surface as a response to unfavorable impact of toxicants. Detoxifying mechanisms (2) and (3) reveal the active role of bioassay systems in detoxification processes. PMID:23123596

Tarasova, A S; Kislan, S L; Fedorova, E S; Kuznetsov, A M; Mogilnaya, O A; Stom, D I; Kudryasheva, N S

2012-12-01

215

A time-resolved image sensor for tubeless streak cameras  

Science.gov (United States)

This paper presents a time-resolved CMOS image sensor with draining-only modulation (DOM) pixels for tube-less streak cameras. Although the conventional streak camera has high time resolution, the device requires high voltage and bulky system due to the structure with a vacuum tube. The proposed time-resolved imager with a simple optics realize a streak camera without any vacuum tubes. The proposed image sensor has DOM pixels, a delay-based pulse generator, and a readout circuitry. The delay-based pulse generator in combination with an in-pixel logic allows us to create and to provide a short gating clock to the pixel array. A prototype time-resolved CMOS image sensor with the proposed pixel is designed and implemented using 0.11um CMOS image sensor technology. The image array has 30(Vertical) x 128(Memory length) pixels with the pixel pitch of 22.4um. .

Yasutomi, Keita; Han, SangMan; Seo, Min-Woong; Takasawa, Taishi; Kagawa, Keiichiro; Kawahito, Shoji

2014-03-01

216

The design of time resolved intensified CCD imaging system  

International Nuclear Information System (INIS)

Coupled the CCD with an image intensifier, the intensified CCD imaging system has such advantages as higher signal gain, higher signal-to-noise ratio (SNR) and higher dynamic range. Time resolution can be achieved by controlling the shutter time of the image intensifier with an electronic pulse. The structures and set-up of the intensified CCD imaging system, and the performance parameters in field use are detailed. The object plane spatial resolution of 5 lp/mm is achieved when enlargement rate is 1. The dynamic range of this system is 38.7, and the synchronous precision is less than 2 ns, the time resolution is 5 ns. (authors)

217

Imaging and Analysis of Pseudomonas aeruginosa Swarming and Rhamnolipid Production ? †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many bacteria spread over surfaces by “swarming” in groups. A problem for scientists who study swarming is the acquisition of statistically significant data that distinguish two observations or detail the temporal patterns and two-dimensional heterogeneities that occur. It is currently difficult to quantify differences between observed swarm phenotypes. Here, we present a method for acquisition of temporal surface motility data using time-lapse fluorescence and bioluminescence imaging. We...

Morris, Joshua D.; Hewitt, Jessica L.; Wolfe, Lawrence G.; Kamatkar, Nachiket G.; Chapman, Sarah M.; Diener, Justin M.; Courtney, Andrew J.; Leevy, W. Matthew; Shrout, Joshua D.

2011-01-01

218

The use of bioluminescence stimulant on the immobilized strain, P. putida mt-2 KG1206, with toluene analog inducers and environmental samples.  

Science.gov (United States)

This study was conducted to investigate the applicability of the stimulant conditions for the bioluminescence activity of a recombinant strain of Pseudomonas putida, mt-2 KG1206, when immobilized using alginate polymer. The bioluminescence activity of the immobilized strain was generally approximately three to five times lower than the subcultured strain, and the activity was observed to slowly decrease. These facts may have been caused by several factors, such as the low biomass and the time required for diffusion into the entrapped biomass. Although different inducers produced different degrees of stimulation, immobilized bacteria modified with KNO(3) consistently produced more bioluminescence than those treated with sodium lactate, regardless of the inducer chemical tested. Cells treated with KNO(3) exhibited 2.8 times greater bioluminescence than that of the control activity. This condition also stimulated the bioluminescence activities of the immobilized bacteria exposed to contaminated groundwater samples. Based on these results, the immobilized KG1206 presented in this research can be used as a portable assay for the purpose of preliminary on-site monitoring of specific inducer contaminants, with subsequent off-site instrumental analysis, suggesting the potential of this immobilized cell for preliminary application in a field-ready bioassay. PMID:19603161

Ko, Kyungsok; Kong, In Chul

2009-09-01

219

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

220

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.)

 
 
 
 
221

Energy current imaging method for time reversal in elastic media  

Energy Technology Data Exchange (ETDEWEB)

An energy current imaging method is presented for use in locating sources of wave energy during the back propagation stage of the time reversal process. During the back propagation phase of an ideal time reversal experiment, wave energy coalesces from all angles of incidence to recreate the source event; after the recreation, wave energy diverges in every direction. An energy current imaging method based on this convergence/divergence behavior has been developed. The energy current imaging method yields a smaller spatial distribution for source reconstruction than is possible with traditional energy imaging methods.

Anderson, Brian E [Los Alamos National Laboratory; Ulrich, Timothy J [Los Alamos National Laboratory; Le Bas, Pierre - Yves A [Los Alamos National Laboratory; Larmat, Carene [Los Alamos National Laboratory; Johnson, Paul A [Los Alamos National Laboratory; Guyer, Robert A [UNR; Griffa, Michele [ETH ZURICH

2009-01-01

222

Real-time interactive display for integral imaging microscopy.  

Science.gov (United States)

A real-time interactive orthographic-view image display of integral imaging (II) microscopy that includes the generation of intermediate-view elemental images (IVEIs) for resolution enhancement is proposed. Unlike the conventional II microscopes, parallel processing through a graphics processing unit is required for real-time display that generates the IVEIs and interactive orthographic-view images in high speed, according to the user interactive input. The real-time directional-view display for the specimen for which 3D information is acquired through II microscopy is successfully demonstrated by using resolution-enhanced elemental image arrays. A user interactive feature is also satisfied in the proposed real-time interactive display for II microscopy. PMID:25090064

Kwon, Ki-Chul; Jeong, Ji-Seong; Erdenebat, Munkh-Uchral; Lim, Young-Tae; Yoo, Kwan-Hee; Kim, Nam

2014-07-10

223

High energy real-time imaging studies.  

Science.gov (United States)

Performance characteristics of high energy real-time radiography (RTR) systems were optimized by interchanging components and varying optical coupling methods. Phosphor screens, fiber optic scintillation plates, monolithic high density glass scintillation...

J. J. Haskins, K. W. Dolan, D. E. Perkins, D. Rikard, D. J. Schneberk

1993-01-01

224

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

225

Real time implementation of the parametric imaging correlation algorithms  

International Nuclear Information System (INIS)

A novel method for functional image evaluation from image set obtained in contrast aided Ultrafast Computed Tomography and Magnetic Resonance Imaging will be presented. The method converts temporal set of images of first-pass transit of injected contrast, to a single parametric image. The main difference between proposed procedure and other widely accepted methods is fast, that our method applies correlation and discrimination analysis to each concentration-time curve, instead of fitting them to the given a priori tracer kinetics model. A stress will be put on execution speed (i.e. shortening of the time required to obtain a perfusion relevant image), and easiest user interface allowing the physician to utilize the system without any technical assistance. Both execution speed and user interface should satisfy requirements in the interventional procedures. (authors)

226

Real-time interactive color flow MR imaging  

International Nuclear Information System (INIS)

This paper reports on the development and testing of an interactive MR flow-imaging system capable of displaying real-time color-coded velocity information on continuously acquired, dynamic, gray-scale morphologic images. Continuous, ultrashort (TR = 8 msec) gradient-echo sequences were used, with alternating gradient moment nulling and flow encoding. Phase and modulus images are reconstructed in real time by dedicated hardware that we have previously developed and interfaced to an otherwise standard 1.5-T imager. Areas of nonzero velocity are coded as color hues in the gray-scale modulus images. The overall update rate is currently two images per second; section location and orientation can be modified interactively

227

Vegetable seed radiosensitivity and kinetic analysis of super-weak bioluminescence  

International Nuclear Information System (INIS)

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

228

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2014-01-01

229

Image reconstruction in PET using time of flight information  

International Nuclear Information System (INIS)

Recent progresses in fast time coincidence technique have permitted the use of time of flight (TOF) information in positron Emission Tomography. We describe the basic concept of positron time of flight imaging and introduce new concepts in order to incorporate the TOF data in the reconstruction process. An algorithm to recover positron activity is then proposed. We describe the image reconstruction in the TTVO1 time of flight camera, the system architecture and the special purpose operators. The time of flight tomography offers large development possibilities and we look forward the new high resolution, high signal-to-noise TOF camera

230

Bioluminescence detection of proteolytic bond cleavage by using recombinant aequorin.  

Science.gov (United States)

Detection of proteolytic bond cleavage was achieved by taking advantage of the bioluminescence emission generated by the photoprotein aequorin. A genetically engineered HIV-1 protease substrate was coupled with a cysteine-free mutant of aequorin by employing the polymerase chain reaction to produce a fusion protein that incorporates an optimum natural protease cleavage site. The fusion protein was immobilized on a solid phase and employed as the substrate for the HIV-1 protease. Proteolytic bond cleavage was detected by a decrease in the bioluminescence generated by the aequorin fusion protein on the solid phase. A dose-response curve for HIV-1 protease was constructed by relating the decrease in bioluminescence signal with varying amounts of the protease. The system was also used to evaluate two competitive and one noncompetitive inhibitor of the HIV-1 protease. Among the advantages of this assay is that by using recombinant methods a complete bioluminescently labeled protease recognition site can be designed and produced. The assay yields very sensitive detection limits, which are inherent to bioluminescence-based methods. An application of this system may be in the high-throughput screening of biopharmaceutical drugs that are potential inhibitors of a target protease. PMID:10847614

Deo, S K; Lewis, J C; Daunert, S

2000-05-15

231

A bioluminescent sensor for high throughput toxicity classification.  

Science.gov (United States)

A high throughput toxicity monitoring and classification biosensor system has been successfully developed using four immobilized bioluminescent Escherichia coli strains, DPD2511, DPD2540, DPD2794 and TV1061, which have plasmids bearing a fusion of a specific promoter to the luxCDABE operon. The bioluminescence of DPD2511 increases in the presence of oxidative damage, DPD2540 by membrane damage, DPD2794 by DNA damage and TV1061 by protein damage. In the developed biosensor these strains are immobilized in a single 96 well plate using an LB-agar matrix, and are able to detect the toxicities of hydrogen peroxide, phenol and mitomycin C in water samples. As the concentration of each chemical was increased, the bioluminescence levels from the corresponding wells, containing either DPD2511, DPD2540, DPD2794 or TV1061, increased. This increase in bioluminescence followed a dose dependent response to the toxic chemicals within a specific concentration range. In particular, each test requires only 4 h to give clear bioluminescent response signature. Storage of the biosensor at 4 degrees C for 2 weeks caused no change in its dose-dependent response. The fast and easy detection of oxidative, membrane, protein and DNA damaging agents in aqueous environments is possible due to the high throughput capability of this biosensor. PMID:12782464

Kim, Byoung Chan; Gu, Man Bock

2003-08-01

232

Application of Wavelet Transform for Image Denoising of Spatially and Time Variable Astronomical Imaging Systems  

Science.gov (United States)

We report on our efforts to formulate algorithms for image signal processing with the spatially and time variant Point-Spread Function (PSF) and inhomogeneous noise of real imaging systems. In this paper we focus on application of the wavelet transform for denoising of the astronomical images with complicated conditions. They influence above all accuracy of the measurements and the new source detection ability. Our aim is to test the usefulness of Wavelet transform (as the standard image processing technique) for astronomical purposes.

Blažek, M.; Anisimova, E.; Páta, P.

233

Application of Wavelet Transform for Image Denoising of Spatially and Time Variable Astronomical Imaging Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report on our efforts to formulate algorithms for image signal processing with the spatially and time variant Point-Spread Function (PSF) and inhomogeneous noise of real imaging systems. In this paper we focus on application of the wavelet transform for denoising of the astronomical images with complicated conditions. They influence above all accuracy of the measurements and the new source detection ability. Our aim is to test the usefulness ofWavelet transform (as the standard image proce...

Blaz?ek, M.; Anisimova, E.; Pa?ta, P.

2011-01-01

234

Fast exposure time decision in multi-exposure HDR imaging  

Science.gov (United States)

Currently available imaging and display system exists the problem of insufficient dynamic range, and the system cannot restore all the information for an high dynamic range (HDR) scene. The number of low dynamic range(LDR) image samples and fastness of exposure time decision impacts the real-time performance of the system dramatically. In order to realize a real-time HDR video acquisition system, this paper proposed a fast and robust method for exposure time selection in under and over exposure area which is based on system response function. The method utilized the monotony of the imaging system. According to this characteristic the exposure time is adjusted to an initial value to make the median value of the image equals to the middle value of the system output range; then adjust the exposure time to make the pixel value on two sides of histogram be the middle value of the system output range. Thus three low dynamic range images are acquired. Experiments show that the proposed method for adjusting the initial exposure time can converge in two iterations which is more fast and stable than average gray control method. As to the exposure time adjusting in under and over exposed area, the proposed method can use the dynamic range of the system more efficiently than fixed exposure time method.

Piao, Yongjie; Jin, Guang

2012-10-01

235

Assessment of radionuclide angiocardiograms using color/time images  

International Nuclear Information System (INIS)

Color images obtained directly from the CRT display of a digital computer were used to assess the passage of radionuclides through the heart. Following separation of the right and left heart images, the former was recorded as blue and the latter as red, after which a composite image of the entire heart was generated. A cardiac chamber or great vessel may be filled during both color/time phases if an intracardiac shunt is present. On the composite image, these overlapping areas appear as either the complementary color or white

236

Velocity map imaging in time of flight mass spectrometry  

International Nuclear Information System (INIS)

A new variation on time of flight mass spectrometry is presented, which uses a fast framing charge coupled device camera to velocity map image multiple product masses in a single acquisition. The technique is demonstrated on two photofragmentation processes, those of CS2 and CH3S2CH3 (dimethyldisulfide) at a photolysis wavelength of 193 nm. In both cases, several mass fragments are imaged simultaneously, and speed distributions and anisotropy parameters are extracted that are comparable to those obtained by imaging each fragment separately in conventional velocity map imaging studies.

237

Imaging regional cerebral vascular transit time  

International Nuclear Information System (INIS)

Regional variations in cerebral capillary transit time (CTT) could affect the accuracy of models used for measurements of cerebral blood flow and metabolism based on positron emission tomography (PET). The authors of this paper developed an autoradiographic method for mapping CTT by simultaneously measuring local cerebral flow (LCBF) and local cerebral capillary blood volume (LCBV). Rats were given intravenous injections of mixtures of 1,850 MBq of Tc-99 m DTPA for (LCBV) and 1,850 kBq of C-14 iodoantipyrine (for LCBF). At the end of the infusions, the rats were killed and their brains were sectioned for autoradiography. To sets of autoradiograms were produced, each predominantly representing exposure from one of the tracers

238

Time resolved Schlieren imaging of DBD actuator flow fields  

Science.gov (United States)

Schlieren imaging methods measure the first derivative of density in the direction of a knife-edge spatial filter. It has been used extensively in aerodynamic research to visualize the structure of flow fields. With a single barrier planer dielectric barrier discharge (DBD) actuator, Schlieren images clearly show the absence of significant vertical air flow normal to the surface, and no more than few millimeters thick induced boundary layer flow. A gated intensified CCD camera along with a Schlieren system can not only visualize the flow field induced by the actuator, but also temporarily resolve the images of the flow and plasma field. Our time resolved images with triangular applied voltage waveforms indicate that several separate discharge regimes occur during positive and negative going half cycles of single and double barrier DBD actuators. Time resolved Schlieren imaging of both single and double barrier DBDs with different applied waveforms, discharge parameters and electrode geometries reveal important information on the induced flow structure.

Nourgostar, Cyrus; Oksuz, Lutfi; Hershkowitz, Noah

2009-10-01

239

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.

240

Iso-luminance counterillumination drove bioluminescent shark radiation.  

Science.gov (United States)

Counterilluminating animals use ventral photogenic organs (photophores) to mimic the residual downwelling light and cloak their silhouette from upward-looking predators. To cope with variable conditions of pelagic light environments they typically adjust their luminescence intensity. Here, we found evidence that bioluminescent sharks instead emit a constant light output and move up and down in the water column to remain cryptic at iso-luminance depth. We observed, across 21 globally distributed shark species, a correlation between capture depth and the proportion of a ventral area occupied by photophores. This information further allowed us, using visual modelling, to provide an adaptive explanation for shark photophore pattern diversity: in species facing moderate predation risk from below, counterilluminating photophores were partially co-opted for bioluminescent signalling, leading to complex patterns. In addition to increase our understanding of pelagic ecosystems our study emphasizes the importance of bioluminescence as a speciation driver. PMID:24608897

Claes, Julien M; Nilsson, Dan-Eric; Straube, Nicolas; Collin, Shaun P; Mallefet, Jérôme

2014-01-01

 
 
 
 
241

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

Science.gov (United States)

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

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

2013-10-01

242

Improving the Image Quality of Synthetic Transmit Aperture Ultrasound Images - Achieving Real-Time In-Vivo Imaging  

DEFF Research Database (Denmark)

Synthetic transmit aperture (STA) imaging has the potential to increase the image quality of medical ultrasound images beyond the levels obtained by conventional imaging techniques (linear, phased, and convex array imaging). Currently, however, in-vivo applications of STA imaging is limited by a low signal-to-noise ratio (SNR), due to the application of a single transducer element at each emission, and higher susceptibility to tissue motion, produced by the summation of sequentially acquired low resolution images. In order to make real-time STA imaging feasible for in-vivo applications, these issues need to solved. The goal of this PhD study has been to find methods that can be used to overcome the above mentioned limitations, and hereby improve the image quality of STA imaging to a clinically desirable level, enabling real-time in-vivo STA imaging. The thesis investigates a new method to increase the SNR, which employs multi-element subapertures and linearly frequency modulated (FM) signals at each emission.The subaperture is applied to emulate a high power spherical wave transmitted by a virtual point source positioned behind the subaperture, and the linear FM signal replaces the conventional short excitation signal to increase the transmitted temporal energy. This approach, named Temporally encoded Multi-element Synthetic transmit aperture (TMS) imaging, is evaluated in detail for linear array and convex array imaging applications using simulations, and phantom and in-vivo experiments. The thesis contains summaries of four journal articles and four corresponding conference publications, which comprise the primary contributions of the PhD. The first two papers give elaborated evaluations of TMS imaging for linear array and convex array imaging, respectively. The results, including initial in-vivo experiments, showed, that TMS imaging can increase the SNR by as much as 17 dB compared to the traditional imaging techniques, which improves the in-vivo image quality to a highly competitive level. An in-vivo evaluation of convex array TMS imaging for abdominal imaging applications is presented in the third paper, based on a clinical trial with 7 healthy male volunteers. Real-time movie sequences of 3 seconds duration were acquired and analyzed by experienced medical doctors using blinded clinical evaluation. The results showed a statistically significant improvement in image quality of convex array TMS imaging compared to conventional convex array imaging. Only minor motion artifacts causing subtle image brightness fluctuations were reported in TMS imaging, which did not depreciate the diagnostic value of the images. The influence of tissue motion and a method for two-dimensional motion compensation is investigated in the fourth and final paper. The method estimates the tissue velocity and motion vii Abstract direction at each image point by correlating image lines beamformed along a set of motion directions and selects the direction and velocity corresponding to the highest correlation. Using these estimates, motion compensation is obtained by tracking the location of each pixel, when reconstructing the low resolution images. The presented phantom and in-vivo results showed, that severe tissue motion has a negative influence on the image quality of STA imaging as expected, but, most importantly, that the proposed method successfully compensates for the motion, thus, retaining the image quality of TMS imaging, when scanning moving tissue. In conclusion, the results of the research presented in this thesis have demonstrated, that TMS imaging is feasible for real-time in-vivo imaging, and that the obtained image quality is highly competitive with the techniques applied in current medical ultrasound scanners. Hereby, the goals of the PhD have been successfully achieved.

Gammelmark, Kim

2004-01-01

243

Coherent temporal imaging with analog time-bandwidth compression  

CERN Document Server

We introduce the concept of coherent temporal imaging and its combination with the anamorphic stretch transform. The new system can measure both temporal profile of fast waveforms as well as their spectrum in real time and at high-throughput. We show that the combination of coherent detection and warped time-frequency mapping also performs time-bandwidth compression. By reducing the temporal width without sacrificing spectral resolution, it addresses the Big Data problem in real time instruments. The proposed method is the first application of the recently demonstrated Anamorphic Stretch Transform to temporal imaging. Using this method narrow spectral features beyond the spectrometer resolution can be captured. At the same time the output bandwidth and hence the record length is minimized. Coherent detection allows the temporal imaging and dispersive Fourier transform systems to operate in the traditional far field as well as in near field regimes.

Asghari, Mohammad H

2013-01-01

244

Quasi-real-time fluorescence imaging with lifetime dependent contrast.  

Science.gov (United States)

Conventional fluorescence lifetime imaging requires complicated algorithms to extract lifetimes of fluorophores and acquisition of multiple data points at progressively longer delay times to characterize tissues. To address diminishing signal-to-noise ratios at these progressively longer time delays, we report a time-resolved fluorescence imaging method, normalized fluorescence yield imaging that does not require the extraction of lifetimes. The concept is to extract the "contrast" instead of the lifetime value of the fluorophores by using simple mathematical algorithms. This process converts differences in decay times directly to different intensities. The technique was verified experimentally using a gated iCCD camera and an ultraviolet light-emitting diode light source. It was shown that this method can distinguish between chemical dyes (Fluorescein and Rhodamine-B) and biomedical samples, such as powders of elastin and collagen. Good contrast was obtained between fluorophores that varied by less than 6% in lifetime. Additionally, it was shown that long gate times up to 16 ns achieve good contrast depending upon the samples to be studied. These results support the feasibility of time-resolved fluorescence imaging without lifetime extraction, which has a potential clinical role in noninvasive real-time imaging. PMID:21895313

Jiang, Pei-Chi; Grundfest, Warren S; Stafsudd, Oscar M

2011-08-01

245

Transmission mode time-reversal super-resolution imaging.  

Science.gov (United States)

The theory of time-reversal super-resolution imaging of point targets embedded in a reciprocal background medium [A. J. Devaney, "Super-resolution imaging using time-reversal and MUSIC," J. Acoust. Soc. Am. (to be published)] is generalized to the case where the transmitter and receiver sensor arrays need not be coincident and for cases where the background medium can be nonreciprocal. The new theory developed herein is based on the singular value decomposition of the generalized multistatic data matrix of the sensor system rather than the standard eigenvector/eigenvalue decomposition of the time-reversal matrix as was employed in the above-mentioned work and other treatments of time-reversal imaging [Prada, Thomas, and Fink, "The iterative time reversal process: Analysis of the convergence," J. Acoust. Soc. Am. 97, 62 (1995); Prada et al., "Decomposition of the time reversal operator: Detection and selective focusing on two scatterers," J. Acoust. Soc. Am. 99, 2067 (1996)]. A generalized multiple signal classification (MUSIC) algorithm is derived that allows super-resolution imaging of both well-resolved and non-well-resolved point targets from arbitrary sensor array geometries. MUSIC exploits the orthogonal nature of the scatterer and noise subspaces defined by the singular vectors of the multistatic data matrix to form scatterer images. The time-reversal/MUSIC algorithm is tested and validated in two computer simulations of offset vertical seismic profiling where the sensor sources are aligned along the earth's surface and the receiver array is aligned along a subsurface borehole. All results demonstrate the high contrast, high resolution imaging capabilities of this new algorithm combination when compared with "classical" backpropagation or field focusing. Above and beyond the application of seismo-acoustic imaging, the time-reversal super-resolution theory has applications in ocean acoustics for target location, and ultrasonic nondestructive evaluation of parts. PMID:12765392

Lehman, Sean K; Devaney, Anthony J

2003-05-01

246

Bioluminescent method to determine non-specific endotoxicosis in therapy.  

Science.gov (United States)

The possibility of using a bioluminescence method for measuring endotoxicosis during therapy has been investigated. Results of our experiments shown that a bioluminescence method can be used as a reliable criterion to monitor the course of disease for patients with bronchitis, ulcerous disease or chronic colecystitis. Assays using both soluble and immobilized reagents are possible. This method does not reveal differences in patients with sepsis, hepatocirrhosis or oncology. The methods are highly sensitive, rapid and simple and allow quantitative determination of the degree of seriousness of illness and estimation of the severity of a patient's condition. At present the test is used to find substances responsible for the toxic state. PMID:10441049

Esimbekova, E N; Kratasyuk, V A; Abakumova, V V

1999-01-01

247

Bioluminescence and Deep Sea Life: All That Glitters... (title provided or enhanced by cataloger)  

Science.gov (United States)

In this lesson, students will investigate absorption, reflection, and scattering of light in the deep sea and discover the concept of bioluminescence. As they proceed, they will learn that white light (visible light) is comprised of all colors of the spectrum, that the quantity of light decreases with increasing depth in the ocean, the quality of light changes with increasing depth, and that red light penetrates water the least and that blue light penetrates water the most. They will also learn that many ocean organisms are bioluminescent, why organisms bioluminesce, and that bioluminescent light is usually blue. In addition, students will learn about several bioluminescent animals through independent research.

248

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

249

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

250

Time-reverse imaging for detection of landmines  

Science.gov (United States)

Time Reversal is based on the fact that most physical laws of nature are invariant for time reversal, i.e., when time t is replaced by -t, most physical laws remain unchanged. Physically this means that by time reversing, a particle will retrace its original path or trajectory. Based on this fact, systems were built which receive reflections or scattering from targets. If this reflected data is recorded, time reversed and launched into the medium again, it will focus back on the targets. This is the basis for experimental time reversal. Time reverse imaging is somewhat different in the sense that scattering from targets are recorded on the sensors, but then back propagated numerically. Narrow-band or single frequency MUSIC based time-reverse imaging algorithms have been proposed in literature for point-like targets. When this algorithm is applied to scattering from an extended target, such as a landmine, the image has good cross-range resolution, but rather poor range resolution. We propose the use of 2-D MUSIC-based algorithm to improve the near-field range resolution, which can then be used in conjunction with single frequency MUSIC to produce a final high-resolution image. A FDTD elastic-wave simulation is used to verify the results using mines and mine-like targets embedded in a heterogenous soil.

Alam, Mubashir; McClellan, James H.; Norville, Pelham D.; Scott, Waymond R., Jr.

2004-09-01

251

Time-Frequency and Time-Scale-Based Fragile Watermarking Methods for Image Authentication  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two fragile image watermarking methods are proposed for image authentication. The first method is based on time-frequency analysis and the second one is based on time-scale analysis. For the first method, the watermark is chosen as an arbitrary nonstationary signal with a particular signature in the time-frequency plane. Experimental results show that this technique is very sensitive to many attacks such as cropping, scaling, translation, JPEG compression, and rotation, making it very...

Braham Barkat; Farook Sattar

2010-01-01

252

Mesoscopic relaxation time of dynamic image correlation spectroscopy  

Directory of Open Access Journals (Sweden)

Full Text Available Dynamical images contain useful information of how the objects behave in time and space. When the system is in biological fluids, the motion of the object is much over-damped; the relaxation time is the characteristics in a diffusive time scale. We have found dynamical states of melting and forming of small nematic domains (10—30 ?m that are exhibited in the suspensions of fd-viruses under applied AC electric field amplitude at low frequency. Dynamic image correlation function is used for extracting the mes- oscopic relaxation times of the dynamical states, which can be employed as an application to other dynamic imaging process of biologically relevant soft condensed matter and biomedical systems.

Kyongok Kang

2010-06-01

253

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

254

Time-frequency techniques applied to ISAR imaging of aircraft  

Science.gov (United States)

The key to successful ISAR imaging is frequency estimation, as the cross range position of scatteres on the target is determined from the differential Doppler shifts of the received radar signal. Many ISAR images are blurred when conventional processing is used. We show that such blurring can result because the full complexity of the target motion is not taken into account. A sufficiently general model shows that the Doppler shifts are time dependent. We give an example using a quadratic time-frequency method on radar data of an aircraft. Irregular motion is detected, and sharp images are formed in the case where the conventional ISAR processor gave a blurred image. The complexity of the target motion was verified using motion reference data.

Sparr, Trygve

2001-03-01

255

Real-time MR image acquistion and reconstruction  

International Nuclear Information System (INIS)

The authors' true real-time MR reconstruction system is based on MR fluoroscopy. The system produces and displays an uninterrupted sequence of six 128(x) x 64(y) images per second in which subject motion can be clearly seen. Spin-warp acquisition techniques are used with standard gradients. In image updating, reconstruction repeats after each group of eight or 16 phase encodings has been measured, instead of being deferred until the complete set of 64 or more phase encodings has been measured. The effect of any phase encoding can be observed in the image within 280 msec of measurement. The authors report how they use the system to track subject motion, create real-time scout images, and accelerate angiography

256

Real-Time Analysis of Large Astronomical Images  

CERN Document Server

Forthcoming instruments designed for high-cadence large-area surveys, such as the Dark Energy Survey and Large Synoptic Survey Telescope, will generate several GB of data products every few minutes during survey operations. Since such surveys are designed to operate with minimal observer interaction, automated real-time analysis of these large images is necessary to ensure uninterrupted production of science-quality data. We describe a software infrastructure suite designed to support such surveys, focusing particularly on ImageHealth, a tool for near-real-time processing of large images. These image manipulation and analysis algorithms were applied to simulated data from the Dark Energy Survey, as well as observed data collected by the Y4KCam on the CTIO 1m telescope and the Mosaic camera on the Blanco telescope. The accuracy and speed of the ImageHealth code in particular were benchmarked against results from SourceExtractor, a standard image analysis tool ubiquitous in the astronomical community. ImageHeal...

Kuehn, K

2012-01-01

257

Time-resolved PHERMEX image restorations constrained with an additional multiply-exposed image  

International Nuclear Information System (INIS)

There are a number of possible industrial and scientific applications of nanosecond cineradiographs. Although the technology exists to produce closely spaced pulses of x rays for this application, the quality of the time-resolved radiographs is severely limited. The limitations arise from the necessity of using a fluorescent screen to convert the transmitted x rays to light and then using electro-optical imaging systems to gate and to record the images with conventional high-speed cameras. It has been proposed that, in addition to the time-resolved images, a conventional multiply exposed radiograph be obtained. This report uses both PHERMEX and conventional photographic simulations to demonstrate that the additional information supplied by the multiply exposed radiograph can be used to improve the quality of digital image restorations of the time-resolved pictures over what could be achieved with the degraded images alone

258

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.

259

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)

260

Real-time evaluation of aggregation using confocal imaging and image analysis tools.  

Science.gov (United States)

Real-time confocal imaging was utilised to monitor the in situ loss of BSA monomers and aggregate formation using Spatial Intensity Distribution Analysis (SpIDA) and Raster Image Correlation Spectroscopy (RICS). At the proof of concept level this work has demonstrated the applicability of RICS and SpIDA for monitoring protein oligomerisation and larger aggregate formation. PMID:24324999

Hamrang, Zahra; Zindy, Egor; Clarke, David; Pluen, Alain

2014-02-01

 
 
 
 
261

The mechanism of electronic excitation in the bacterial bioluminescent reaction  

International Nuclear Information System (INIS)

The current state of the problem of formation of the electron-excited product in the chemiluminescent reaction that underlies the bacterial luminescence is analysed. Various schemes of chemical transformations capable of producing a bacterial bioluminescence emitter are presented. The problem of excitation of secondary emitters is considered; two possible mechanisms of their excitation are analysed.

262

A bioluminescent signal system: detection of chemical toxicants in water.  

Science.gov (United States)

Prototype technologies of a bioluminescent signal system (BSS) based on the luminous bacterium Photobacterium phosphoreum and three enzymatic bioluminescence systems have been proposed for detecting and signalling the presence of toxicants in water systems. A number of pesticides, mostly known as poisonous substances, similar in their structures and physicochemical properties, have been taken as model compounds of chemical agents. The effect of toxicants (organophosphates, derivatives of dithiocarbamide acid, and pyrethroid preparations) on the bioluminescence of the four systems has been analysed. EC(50) and EC(80) have been determined and compared to the maximum permissible concentration for each of the analysed substances. The triple-enzyme systems with ADH and trypsin have been shown to be more sensitive to organophosphorous compounds (0.13-11 mg/L), while the triple-enzyme system with trypsin is highly sensitive to lipotropic poison, a derivative of dithiocarbamine acid (0.03 mg/L). Sensitivities of the triple-enzyme systems to pyrethroid preparations are similar to those of luminous bacteria (0.9-5 mg/L). The results can be used to construct an alarm-test bioluminescence system for detecting chemical toxicants, based on intact bacteria or enzyme systems. PMID:17603816

Vetrova, E; Esimbekova, E; Remmel, N; Kotova, S; Beloskov, N; Kratasyuk, V; Gitelson, I

2007-01-01

263

Bioluminescence characteristics of the fruiting body of Mycena chlorophos.  

Science.gov (United States)

Bioluminescent fungi are widely distributed on land and most belong to the class Basidomycetes. Light of about 530 nm wavelength maximum is emitted continuously. The molecular basis for the light-emitting process remains unclear. We investigated the characteristics of the bioluminescence using cultivated fruiting bodies of M. chlorophos. Only fresh fruiting bodies exhibited long-lasting light emission; rapid decay of light emission was observed with frozen and freeze-dried samples. Freeze-dried samples can be stored at room temperature under dry conditions and may be useful for the isolation of luciferin. The light emission of the fresh fruiting bodies was maintained in various buffers at varying pH; it could be stopped with pH 4 acetate buffer and could be recovered at pH 6. The isolation of luciferin from the fresh fruiting bodies might be possible by the control of buffer pH. The effect of temperature on the light emission of fruiting bodies indicated that bioluminescence in M. chlorophos may involve enzymatic reaction(s). The solubilization of bioluminescent components from the fruiting bodies could not be achieved with various surfactants. PMID:21370386

Mori, Kenichi; Kojima, Satoshi; Maki, Shojiro; Hirano, Takashi; Niwa, Haruki

2011-01-01

264

Source Reconstruction for Spectrally-resolved Bioluminescence Tomography with Sparse A priori Information  

Science.gov (United States)

Through restoration of the light source information in small animals in vivo, optical molecular imaging, such as fluorescence molecular tomography (FMT) and bioluminescence tomography (BLT), can depict biological and physiological changes observed using molecular probes. A priori information plays an indispensable role in tomographic reconstruction. As a type of a priori information, the sparsity characteristic of the light source has not been sufficiently considered to date. In this paper, we introduce a compressed sensing method to develop a new tomographic algorithm for spectrally-resolved bioluminescence tomography. This method uses the nature of the source sparsity to improve the reconstruction quality with a regularization implementation. Based on verification of the inverse crime, the proposed algorithm is validated with Monte Carlo-based synthetic data and the popular Tikhonov regularization method. Testing with different noise levels and single/multiple source settings at different depths demonstrates the improved performance of this algorithm. Experimental reconstruction with a mouse-shaped phantom further shows the potential of the proposed algorithm. PMID:19434138

Lu, Yujie; Zhang, Xiaoqun; Douraghy, Ali; Stout, David; Tian, Jie; Chan, Tony F.; Chatziioannou, Arion F.

2009-01-01

265

Detection of heterogeneous substrate distributions in tumors and spheroids by bioluminescence  

International Nuclear Information System (INIS)

Heterogeneous cell populations within solid tumors often limit non-surgical tumor therapies. Partially, the biological variability among cancer cells in vivo is attributable to a non-uniform oxygenation and pH distribution as a consequence of spatial and temporal heterogeneities in the tumor microcirculation. In order to evaluate whether such inhomogeneities may also be found in the distribution of nutrients and metabolites, a method, originally developed for the determination of regional substrate distributions in brain tissue; has been applied to cryobiopsies of human tumor xenografts and of tumors in patients. In addition, this method has been adapted to multicellular tumor spheroids of human origin. The bioluminescence reactions are enzymatically linked to the substrate of interest. A cold cyrostat section of the frozen enzyme solution is laid upon a frozen cryostat section of a tumor or of a spheroid. Bioluminescence recorded by film exposure occurs upon thawing these sections. The exposed film is then evaluated by microdensitometry and by special image analysis. The regional distributions of glucose, lactate and ATP are obtained in relative units. The results show that all substances investigated exhibit large regional differences reflecting a great heterogeneity of the metabolic micromilieu in malignant tumors and even within tumor spheroids

266

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

267

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. PMID:22938303

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

2012-08-01

268

360-degree dense multiview image acquisition system using time multiplexing  

Science.gov (United States)

A novel 360-degree 3D image acquisition system that captures multi-view images with narrow view interval is proposed. The system consists of a scanning optics system and a high-speed camera. The scanning optics system is composed of a double-parabolic mirror shell and a rotating flat mirror tilted at 45 degrees to the horizontal plane. The mirror shell produces a real image of an object that is placed at the bottom of the shell. The mirror shell is modified from usual system which is used as 3D illusion toy so that the real image can be captured from right horizontal viewing direction. The rotating mirror in the real image reflects the image to the camera-axis direction. The reflected image observed from the camera varies according to the angle of the rotating mirror. This means that the camera can capture the object from various viewing directions that are determined by the angle of the rotating mirror. To acquire the time-varying reflected images, we use a high-speed camera that is synchronized with the angle of the rotating mirror. We have used a high-speed camera which resolution is 256×256 and the maximum frame rate is 10000fps at the resolution. Rotating speed of the tilted flat mirror is about 27 rev./sec. The number of views is 360. The focus length of parabolic mirrors is 73mm and diameter is 360mm. Objects which length is less than about 30mm can be acquired. Captured images are compensated rotation and distortion caused by double-parabolic mirror system, and reproduced as 3D moving images by Seelinder display.

Yendo, Tomohiro; Fujii, Toshiaki; Panahpour Tehrani, Mehrdad; Tanimoto, Masayuki

2010-02-01

269

Experimental ultrasound system for real-time synthetic imaging  

DEFF Research Database (Denmark)

Digital signal processing is being employed more and more in modern ultrasound scanners. This has made it possible to do dynamic receive focusing for each sample and implement other advanced imaging methods. The processing, however, has to be very fast and cost-effective at the same time. Dedicated chips are used in order to do real time processing. This often makes it difficult to implement radically different imaging strategies on one platform and makes the scanners less accessible for research purposes. Here flexibility is the prime concern, and the storage of data from all transducer elements over 5 to 10 seconds is needed to perform clinical evaluation of synthetic and 3D imaging. This paper describes a real-time system specifically designed for research purposes. The purpose of the system is to make it possible to acquire multi-channel data in real-time from clinical multi-element ultrasound transducers, and to enable real-time or near realtime processing of the acquired data. The system will be capable of performing the processing for the currently available imaging methods, and will make it possible to perform initial trials in a clinical environment with new imaging modalities for synthetic aperture imaging, 2D and 3D B-mode and velocity imaging. The system can be used with 128 element transducers and can excite 128 channels and receive and sample data from 64 channels simultaneously at 40 MHz with 12 bits precision. Data can be processed in real time using the system's 80 signal processing units or it can be stored directly in RAM. The system has 24 GBytes RAM and can thus store 8 seconds of multi-channel data. It is fully software programmable and its signal processing units can also be reconfigured under software control. The control of the system is done over an Ethernet using C and Matlab. Programs for doing e.g. B-mode imaging can directly be written in Matlab and executed on the system over the net from any workstation running Matlab. The overall system concept is presented and an example ofa 20 lines script for doing phased array B-mode imaging is presented.

Jensen, JØrgen Arendt; Pedersen, Henrik MØller

1999-01-01

270

Near infrared bioluminescence resonance energy transfer from firefly luciferase-quantum dot bionanoconjugates.  

Science.gov (United States)

The bioluminescence resonance energy transfer (BRET) between firefly luciferase enzymes and semiconductive quantum dots (QDs) with near infrared emission is described. The QD were phase transferred to aqueous buffers using a histidine mediated phase transfer route, and incubated with a hexahistidine tagged, green emitting variant of firefly luciferase from Photinus pyralis (PPyGRTS). The PPyGRTS were bound to the QD interface via the hexahistidine tag, which effectively displaces the histidine layer and binds directly to the QD interfaces, allowing for short donor-acceptor distances (?5.5 nm). Due to this, high BRET efficiency ratios of ?5 were obtained. These PPyGRTS-QD bio-nano conjugates were characterized by transmission electron microscopy, thermal gravimetric analysis, Fourier transform infrared spectroscopy and BRET emission studies. The final optimized conjugate was easily observable by night vision imaging, demonstrating the potential of these materials in imaging and signaling/sensing applications. PMID:25414169

Alam, Rabeka; Karam, Liliana M; Doane, Tennyson L; Zylstra, Joshua; Fontaine, Danielle M; Branchini, Bruce R; Maye, Mathew M

2014-12-12

271

Long-term Time Lapse Imaging of Mouse Cochlear Explants.  

Science.gov (United States)

Here we present a method for long-term time-lapse imaging of live embryonic mouse cochlear explants. The developmental program responsible for building the highly ordered, complex structure of the mammalian cochlea proceeds for around ten days. In order to study changes in gene expression over this period and their response to pharmaceutical or genetic manipulation, long-term imaging is necessary. Previously, live imaging has typically been limited by the viability of explanted tissue in a humidified chamber atop a standard microscope. Difficulty in maintaining optimal conditions for culture growth with regard to humidity and temperature has placed limits on the length of imaging experiments. A microscope integrated into a modified tissue culture incubator provides an excellent environment for long term-live imaging. In this method we demonstrate how to establish embryonic mouse cochlear explants and how to use an incubator microscope to conduct time lapse imaging using both bright field and fluorescent microscopy to examine the behavior of a typical embryonic day (E) 13 cochlear explant and Sox2, a marker of the prosensory cells of the cochlea, over 5 days. PMID:25407734

Mulvaney, Joanna F; Dabdoub, Alain

2014-01-01

272

Application of Wavelet Transform for Image Denoising of Spatially and Time Variable Astronomical Imaging Systems  

Directory of Open Access Journals (Sweden)

Full Text Available We report on our efforts to formulate algorithms for image signal processing with the spatially and time variant Point-Spread Function (PSF and inhomogeneous noise of real imaging systems. In this paper we focus on application of the wavelet transform for denoising of the astronomical images with complicated conditions. They influence above all accuracy of the measurements and the new source detection ability. Our aim is to test the usefulness ofWavelet transform (as the standard image processing technique for astronomical purposes.

M. Blažek

2011-01-01

273

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

274

Construction and validation of improved triple fusion reporter gene vectors for molecular imaging of living subjects.  

Science.gov (United States)

Multimodality imaging using several reporter genes and imaging technologies has become an increasingly important tool in determining the location(s), magnitude, and time variation of reporter gene expression in small animals. We have reported construction and validation of several triple fusion genes composed of a bioluminescent, a fluorescent, and a positron emission tomography (PET) reporter gene in cell culture and in living subjects. However, the bioluminescent and fluorescent components of fusion reporter proteins encoded by these vectors possess lesser activities when compared with the bioluminescent and fluorescent components of the nonfusions. In this study, we first created a mutant (mtfl) of a thermostable firefly luciferase (tfl) bearing the peroxisome localization signal to have greater cytoplasmic localization and improved access for its substrate, d-luciferin. Comparison between the three luciferases [mtfl, tfl, and firefly luciferase (fl)] both in cell culture and in living mice revealed that mtfl possessed 6- to 10-fold (in vitro) and 2-fold (in vivo) higher activity than fl. The improved version of the triple fusion vector carrying mtfl as the bioluminescent reporter component showed significantly (P Heteractis crispa, and coral Discosoma, respectively) evaluated, mrfp1 was able to preserve highest expression as a component of the triple fusion reporter gene for in vivo fluorescence imaging. A truncated version of wild-type herpes simplex virus 1 (HSV1) thymidine kinase gene (wttk) retained a higher expression level than the truncated mutant HSV1-sr39 TK (ttk) as the third reporter component of this improved triple fusion vector. Multimodality imaging of tumor-bearing mice using bioluminescence and microPET showed higher luciferase activity [(2.7 +/- 0.1 versus 1.9 +/- 0.1) x (10(6) p/s/cm(2)/sr)] but similar level of fluorine-18-labeled 2'-fluoro-2'-deoxyarabinofuranosyl-5-ethyluracil (18F-FEAU) uptake (1.37 +/- 0.15 versus 1.37 +/- 0.2) percentage injected dose per gram] by mtfl-mrfp1-wttk-expressing tumors compared with the fl-mrfp1-wttk-expressing tumors. Both tumors showed 4- to 5-fold higher accumulation (P < 0.05) of 18F-FEAU than fluorine-18-labeled 9-(4-fluoro-3-hydroxymethylbutyl)guanine. This improved triple fusion reporter vector will enable high sensitivity detection of lower numbers of cells from living animals using the combined bioluminescence, fluorescence, and microPET imaging techniques. PMID:17409415

Ray, Pritha; Tsien, Roger; Gambhir, Sanjiv Sam

2007-04-01

275

Real-time quantitative phase imaging for cell studies  

Science.gov (United States)

Most biological cells are not clearly visible with a bright field microscope. Several methods have been developed to improve contrast in cell imaging, including use of exogenous contrast agents such as fluorescence microscopy, as well as utilizing properties of light-specimen interaction for optics design, to reveal the endogenous contrast, such as phase contrast microscopy (PCM) and differential interference contrast (DIC) microscopy. Although PCM and DIC methods significantly improve the image contrast without the need for staining agents, they only provide qualitative information about the phase change induced by the cells as light passes through them. Quantitative phase imaging (QPI) has recently emerged as an effective imaging tool which provides not only better image contrast but also cell-induced phase shifts in the optical pathlength, thus allowing nanometer-scale measurements of structures and dynamics of the cells. Other important aspects of an imaging system are its imaging speed and throughput. High-throughput, high-speed, real-time quantitative phase imaging with high spatial and temporal sensitivity is highly desirable in many applications including applied physics and biomedicine. In this dissertation, to address this need, I discuss the development of such an imaging system that includes the white light diffraction phase microscopy (wDPM), a new optical imaging method, and image reconstruction/analysis algorithms using graphics processing units (GPUs). wDPM can measure optical pathlength changes at nanometer scale both spatially and temporally with single-shot image acquisition, enabling very fast imaging. I also exploit the broadband spectrum of white light used as the light source in wDPM to develop a system called spectroscopic diffraction phase microscopy (sDPM). This sDPM system allows QPI measurements at several wavelengths, which solves the problem of thickness and refractive index coupling in the phase shifts induced by the cell, and which also may help visualize more-complex cell structures. Owing to its high spatial and temporal sensitivity and single-shot acquisition, wDPM enables measurement of nanometer-scale dynamic processes of cells at very high rate and measurement of cell growth because of the linear relationship between a cell-induced phase shift and its dry mass. The parallel algorithms and software tools I developed allow real-time QPI imaging and online image analysis at frame rates of up to 40 megapixel-size images per second. This capability allows very high throughput of several thousands of cells in imaging mode and eliminates the need of storing the images since we only need to store processed data, which is much smaller in storage size. Finally, I present the capability of the system by showing an application in red blood cell screening, which can be used as a diagnostic tool in blood testing and may pave the way for digital hematology and remote diagnostics.

Pham, Hoa Vinh

276

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

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

Kandaswamy, Krishna Kumar

2011-08-17

277

Real-Time Video Imaging of Protease Expression In Vivo  

Directory of Open Access Journals (Sweden)

Full Text Available We demonstrate the first true real-time in vivo video imaging of extracellular protease expression using an ultrafast-acting and extended-use activatable probe. This simple, one-step technique is capable of boosting fluorescent signals upon target protease cleavage as early as 30 minutes from injection in a small animal model and is able to sustain the strong fluorescent signal up to 24 hours. Using this method, we video imaged the expression and inhibition of matrix metalloproteinases (MMPs in a tumor-bearing mouse model. The current platform can be universally applied to any target protease of interest with a known peptide substrate and is adaptable to a wide range of real-time imaging applications with high throughputs such as for in vivo drug screening, examinations of the therapeutic efficacy of drugs, and monitoring of disease onset and development in animal models.

Lei Zhu, Jin Xie, Magdalena Swierczewska, Fan Zhang, Qimeng Quan, Ying Ma, Xuexun Fang, Kwangmeyung Kim, Seulki Lee, Xiaoyuan Chen

2011-01-01

278

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.''

279

Real-time synthesis of image slices in deformed tissue from nominal volume images.  

Science.gov (United States)

This paper presents a fast image synthesis procedure for elastic volumes under deformation. Given the node displacements of a mesh and the 3D image voxel data of an undeformed volume, the method maps the image plane pixels to be synthesized from the deformed configuration back to the nominal pre-deformed configuration, where the pixel intensities are obtained easily through interpolation in the regular-grid structure of the voxel volume. For smooth interpolation, this mapping requires the identification of the mesh element enclosing each image pixel. To accelerate this point location procedure, a fast method of marking the image pixels is employed by finding the intersection of the mesh and the image, and marking this intersection on the image pixels using Bresenham's line drawing algorithm. A deformable tissue phantom was constructed, it was modeled using the finite element method, and its 3D ultrasound volume was acquired in its undeformed state. Actual B-mode images of the phantom under deformation by the ultrasound probe were then compared with the corresponding synthesized images simulated for the same deformations. Results show that realistic images can be synthesized in real-time using the proposed technique. PMID:18051084

Goksel, Orcun; Salcudean, Septimiu E

2007-01-01

280

Time-resolved fast neutron imaging: simulation of detector performance  

CERN Document Server

We have analyzed and compared the performance of two novel fast-neutron imaging methods with time-of-flight spectroscopy capability. Using MCNP and GEANT code simulations of neutron and charged-particle transport in the detectors, key parameters such as detection efficiency, the amount of energy deposited in the converter and the spatial resolution of both detector variants have been evaluated.

Vartsky, D; Goldberg, M B; Mardor, I; Feldman, G; Bar, D; Shor, A; Dangendorf, V; Laczko, G; Breskin, Amos; Chechik, R

2004-01-01

 
 
 
 
281

Optimal Stopping Time Formulation of Adaptive Image Filtering  

International Nuclear Information System (INIS)

This paper presents an approach to image filtering based on an optimal stopping time problem for the evolution equation describing the filtering kernel. This approach allows us to obtain easily an adaptivity of the filter with respect to the noise level. Well-posedness of the problem and convergence of fully discrete approximations are proved and numerical examples are presented and discussed

282

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

283

Real-time synthetic aperture imaging: opportunities and challenges  

DEFF Research Database (Denmark)

Synthetic aperture (SA) ultrasound imaging has not been introduced in commercial scanners mainly due to the computational cost associated with the hardware implementation of this imaging modality. SA imaging redefines the term beamformed line. Since the acquired information comes from all points in the region of interest it is possible to beamform the signals along a desired path, thus, improving the estimation of blood flow. The transmission of coded excitations makes it possible to achieve higher contrast and larger penetration depth compared to "conventional" scanners. This paper presents the development and implementation of the signal processing stages employed in SA imaging: compression of received data acquired using codes, and beamforming. The goal was to implement the system using commercially available field programmable gate arrays. The compression filter operates on frequency modulated pulses with duration of up to 50 mus sampled at 70 MHz. The beamformer can process data from 256 channels at a pulse repetition frequency of 5000 Hz and produces 192 lines of 1024 complex samples in real time. The lines are described by their origin, direction, length and distance between two samples in 3D. This parametric description makes it possible to quickly change the image geometry during scanning, thus enabling adaptive imaging and precise flow estimation. The paper addresses problems such as large bandwidth and computational load and gives the solutions that have been adopted for the implementation.

Nikolov, Svetoslav; Tomov, Borislav Gueorguiev

2006-01-01

284

Time series analysis of brain regional volume by MR image  

International Nuclear Information System (INIS)

The present study proposed a methodology of time series analysis of volumes of frontal, parietal, temporal and occipital lobes and cerebellum because such volumetric reports along the process of individual's aging have been scarcely presented. Subjects analyzed were brain images of 2 healthy males and 18 females of av. age of 69.0 y, of which T1-weighted 3D SPGR (spoiled gradient recalled in the steady state) acquisitions with a GE SIGNA EXCITE HD 1.5T machine were conducted for 4 times in the time series of 42-50 months. The image size was 256 x 256 x (86-124) voxels with digitization level 16 bits. As the template for the regions, the standard gray matter atlas (icbn452atlasprobabilitygray) and its labeled one (icbn.Labels), provided by UCLA Laboratory of Neuro Imaging, were used for individual's standardization. Segmentation, normalization and coregistration were performed with the MR imaging software SPM8 (Statistic Parametric Mapping 8). Volumes of regions were calculated as their voxel ratio to the whole brain voxel in percent. It was found that the regional volumes decreased with aging in all above lobes examined and cerebellum in average percent per year of -0.11, -0.07, -0.04, -0.02, and -0.03, respectively. The procedure for calculation of the regional volumes, which has been manually operated hitherto, can be automatically conducted for the individual brain using the standard atlases above. (T.T.)

285

Imaging the time sequence of latent electrostatic fingerprints  

Science.gov (United States)

Biometric identification for forensic investigations and security continues to depend on classic fingerprinting in many instances. Existing techniques rely on either visible deposits or hidden (latent) fingerprints resulting from the transfer of residues from the finger to the surface. However, one of the limitations of classic fingerprinting, for use as forensic evidence, is in determining a time sequence of events. It is extremely difficult to establish a timeline, from fingerprint evidence alone. We present the capability of a new technique which images the electrical charge deposited by tribocharging when a finger contacts an electrically insulated surface. The method is applicable to insulating surfaces and has been tested on PVC, PTFE, Acetate and PVDF sheets. The latent electrostatic charge pattern is detected using a novel, microscopic, electric potential sensor. The sensor is capable of imaging static charge distributions non-invasively, with no discharging effect on the sample. We present data showing the decay of the charge image with time, over a period up to 14 days. This capability has two major implications. First this technique does not suffer from ambiguities caused by a history of old fingerprints and second it has the potential to allow the time sequence of recent charge fingerprint images to be determined.

Watson, P.; Prance, R. J.; Prance, H.; Beardsmore-Rust, S. T.

2010-10-01

286

Image reconstruction in time-of-flight positron emission tomography  

International Nuclear Information System (INIS)

Five algorithms for image reconstruction in time-of-flight assisted positron emission tomography have been studied. These algorithms include three approaches previously described in the literature and two new methods recently developed in our institute. Computer simulation studies have been performed to evaluate the relative merits of these various techniques. Performance indices such as computational efficiency, reconstructed image resolution, and signal-to-noise ratio have been investigated. Results from the analysis suggest that the two new methods may offer some potential advantages over other algorithms. (Auth.)

287

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

288

Digital image processing of real-time radiographic images for waste characterization  

International Nuclear Information System (INIS)

A digital image processing system has been developed for use in real-time radiographic analysis. This system provides tools for quantitative analysis of waste container contents such as volumes of liquids and dimensions of objects. The system processes incoming video signals in real-time and is controlled via a Windows user interface

289

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

290

Time-resolved tomographic images of a relativistic electron beam  

Energy Technology Data Exchange (ETDEWEB)

We obtained a sequential series of time-resolved tomographic two-dimensional images of a 4.5-MeV, 6-kA, 30-ns electron beam. Three linear fiber-optic arrays of 30 or 60 fibers each were positioned around the beam axis at 0/sup 0/, 61/sup 0/, and 117/sup 0/. The beam interacting with nitrogen at 20 Torr emitted light that was focused onto the fiber arrays and transmitted to a streak camera where the data were recorded on film. The film was digitized, and two-dimensional images were reconstructed using the maximum-entropy tomographic technique. These images were then combined to produce an ultra-high-speed movie of the electron-beam pulse.

Koehler, H.A.; Jacoby, B.A.; Nelson, M.

1984-07-01

291

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)

292

Real-Time, Holographic, Dynamic Image-Storage Device  

Science.gov (United States)

Solid-state device developed for high-speed acquisition, dynamic storage, and amplification of three-dimensional holographic images. Holograms generated via four-wave mixing in two or more photorefractive crystals (or subelements of single crystal) to create single-crystal or multicrystal oscillator. Apparatus provides dynamic storage of holographic image of object after electronic shutter closed to turn off object beam. Provides capability to store, amplify, process, and transmit time-varying, two-dimensional, spatial information. Developments include sensors, actuators, and optical computers operating at speeds on order of speed of light. Potential in applications in which need for high-speed acquisition and storage of three-dimensional holographic images.

Montgomery, Raymond C.; Lafleur, Sharon S.

1995-01-01

293

Time-resolved tomographic images of a relativistic electron beam  

International Nuclear Information System (INIS)

We obtained a sequential series of time-resolved tomographic two-dimensional images of a 4.5-MeV, 6-kA, 30-ns electron beam. Three linear fiber-optic arrays of 30 or 60 fibers each were positioned around the beam axis at 00, 610, and 1170. The beam interacting with nitrogen at 20 Torr emitted light that was focused onto the fiber arrays and transmitted to a streak camera where the data were recorded on film. The film was digitized, and two-dimensional images were reconstructed using the maximum-entropy tomographic technique. These images were then combined to produce an ultra-high-speed movie of the electron-beam pulse

294

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

295

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

296

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

297

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 < 0.05. Results showed that women had significantly higher temperature variations than men (p < 0.01) along the time. In men, only the body region of the abdomen obtained a significant variance (p < 0.05) on the analyzed period, both in the anterior and posterior part. In women, the anterior abdomen and thighs, and the posterior part of the hands, forearms and abdomen showed significant differences (p < 0.05). Based on our results, it can be concluded that the time in rest condition required reaching a TSK balance in 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

298

Time-frequency analysis of functional optical mammographic images  

Science.gov (United States)

We have introduced working technology that provides for time-series imaging of the hemoglobin signal in large tissue structures. In this study we have explored our ability to detect aberrant time-frequency responses of breast vasculature for subjects with Stage II breast cancer at rest and in response to simple provocations. The hypothesis being explored is that time-series imaging will be sensitive to the known structural and functional malformations of the tumor vasculature. Mammographic studies were conducted using an adjustable hemisheric measuring head containing 21 source and 21 detector locations (441 source-detector pairs). Simultaneous dual-wavelength studies were performed at 760 and 830 nm at a framing rate of ~2.7 Hz. Optical measures were performed on women lying prone with the breast hanging in a pendant position. Two class of measures were performed: (1) 20- minute baseline measure wherein the subject was at rest; (2) provocation studies wherein the subject was asked to perform some simple breathing maneuvers. Collected data were analyzed to identify the time-frequency structure and central tendencies of the detector responses and those of the image time series. Imaging data were generated using the Normalized Difference Method (Pei et al., Appl. Opt. 40, 5755-5769, 2001). Results obtained clearly document three classes of anomalies when compared to the normal contralateral breast. 1) Breast tumors exhibit altered oxygen supply/demand imbalance in response to an oxidative challenge (breath hold). 2) The vasomotor response of the tumor vasculature is mainly depressed and exhibits an altered modulation. 3) The affected area of the breast wherein the altered vasomotor signature is seen extends well beyond the limits of the tumor itself.

Barbour, Randall L.; Graber, Harry L.; Schmitz, Christoph H.; Tarantini, Frank; Khoury, Georges; Naar, David J.; Panetta, Thomas F.; Lewis, Theophilus; Pei, Yaling

2003-07-01

299

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

Energy Technology Data Exchange (ETDEWEB)

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

Seliger, H H

1976-01-01

300

Distribution of bioluminescent fungi across old-growth and secondary tropical rain forest in Costa Rica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Most research on bioluminescent fungi is concentrated on their taxonomic relationships, while the basics of their natural history and ecological relationships are poorly understood. In this study, we compared the distribution of bioluminescent fungi between old-growth and secondary forest as related to four different soil types at the tropical rainforest of La Selva Biological Station in Costa Rica. The study was conducted during the wet season of 2009. Bioluminescent fungi were sought follow...

Carolina Seas-Carvajal; Gerardo Avalos

2013-01-01

 
 
 
 
301

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

302

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

303

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

Science.gov (United States)

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

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

2014-05-01

304

Seasonal variation of deep-sea bioluminescence in the Ionian Sea  

International Nuclear Information System (INIS)

The ICDeep (Image Intensified Charge Coupled Device for Deep sea research) profiler was used to measure the density of deep bioluminescent animals (BL) through the water column in the east, west and mid-Ionian Sea and in the Algerian Basin. A west to east decrease in BL density was found. Generalized additive modelling was used to investigate seasonal variation in the east and west Ionian Sea (NESTOR and NEMO neutrino telescope sites, respectively) from BL measurements in autumn 2008 and spring 2009. A significant seasonal effect was found in the west Ionian Sea (p<0.001), where a deep autumnal peak in BL density occurred between 500 and 2400 m. No significant seasonal variation in BL density was found in the east Ionian Sea (p=0.07). In both spring and autumn, significant differences in BL density were found through the water column between the east and west Ionian Sea (p<0.001).

305

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

International Nuclear Information System (INIS)

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

306

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

307

Seasonal variation of deep-sea bioluminescence in the Ionian Sea  

Energy Technology Data Exchange (ETDEWEB)

The ICDeep (Image Intensified Charge Coupled Device for Deep sea research) profiler was used to measure the density of deep bioluminescent animals (BL) through the water column in the east, west and mid-Ionian Sea and in the Algerian Basin. A west to east decrease in BL density was found. Generalized additive modelling was used to investigate seasonal variation in the east and west Ionian Sea (NESTOR and NEMO neutrino telescope sites, respectively) from BL measurements in autumn 2008 and spring 2009. A significant seasonal effect was found in the west Ionian Sea (p<0.001), where a deep autumnal peak in BL density occurred between 500 and 2400 m. No significant seasonal variation in BL density was found in the east Ionian Sea (p=0.07). In both spring and autumn, significant differences in BL density were found through the water column between the east and west Ionian Sea (p<0.001).

Craig, Jessica, E-mail: j.craig@abdn.ac.u [University of Aberdeen, Oceanlab, Main Street, Newburgh, Aberdeenshire, AB41 6AA (United Kingdom); Jamieson, Alan J.; Bagley, Philip M.; Priede, Imants G. [University of Aberdeen, Oceanlab, Main Street, Newburgh, Aberdeenshire, AB41 6AA (United Kingdom)

2011-01-21

308

Real-Time Digital Compression Of Television Image Data  

Science.gov (United States)

Digital encoding/decoding system compresses color television image data in real time for transmission at lower data rates and, consequently, lower bandwidths. Implements predictive coding process, in which each picture element (pixel) predicted from values of prior neighboring pixels, and coded transmission expresses difference between actual and predicted current values. Combines differential pulse-code modulation process with non-linear, nonadaptive predictor, nonuniform quantizer, and multilevel Huffman encoder.

Barnes, Scott P.; Shalkhauser, Mary JO; Whyte, Wayne A., Jr.

1990-01-01

309

IMAGING THE SOLAR TACHOCLINE BY TIME-DISTANCE HELIOSEISMOLOGY  

International Nuclear Information System (INIS)

The solar tachocline at the bottom of the convection zone is an important region for the dynamics of the Sun and the solar dynamo. In this region, the sound speed inferred by global helioseismology exhibits a bump of approximately 0.4% relative to the standard solar model. Global helioseismology does not provide any information on possible latitudinal variations or asymmetries between the northern and southern hemisphere. Here, we develop a time-distance helioseismology technique, including surface- and deep-focusing measurement schemes and a combination of both, for two-dimensional tomographic imaging of the solar tachocline that infers radial and latitudinal variations in the sound speed. We test the technique using artificial solar oscillation data obtained from numerical simulations. The technique successfully recovers major features of the simplified tachocline models. The technique is then applied to SOHO/MDI medium-l data and provides for the first time a full two-dimensional sound-speed perturbation image of the solar tachocline. The one-dimensional radial profile obtained by latitudinal averaging of the image is in good agreement with the previous global helioseismology result. It is found that the amplitude of the sound-speed perturbation at the tachocline varies with latitude, but it is not clear whether this is in part or fully an effect of instrumental distortion. Our initial results demonstrate that time-distance helioseismology can be used to probe the helioseismology can be used to probe the deep interior structure of the Sun, including the solar tachocline.

310

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

311

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

312

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

313

Integration of image exposure time into a modified laser speckle imaging method  

Energy Technology Data Exchange (ETDEWEB)

Speckle-based methods have been developed to characterize tissue blood flow and perfusion. One such method, called modified laser speckle imaging (mLSI), enables computation of blood flow maps with relatively high spatial resolution. Although it is known that the sensitivity and noise in LSI measurements depend on image exposure time, a fundamental disadvantage of mLSI is that it does not take into account this parameter. In this work, we integrate the exposure time into the mLSI method and provide experimental support of our approach with measurements from an in vitro flow phantom.

RamIrez-San-Juan, J C; Salazar-Hermenegildo, N; Ramos-Garcia, R; Munoz-Lopez, J [Optics Department, INAOE, Puebla (Mexico); Huang, Y C [Department of Electrical Engineering and Computer Science, University of California, Irvine, CA (United States); Choi, B, E-mail: jcram@inaoep.m [Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA (United States)

2010-11-21

314

Integration of image exposure time into a modified laser speckle imaging method  

Science.gov (United States)

Speckle-based methods have been developed to characterize tissue blood flow and perfusion. One such method, called modified laser speckle imaging (mLSI), enables computation of blood flow maps with relatively high spatial resolution. Although it is known that the sensitivity and noise in LSI measurements depend on image exposure time, a fundamental disadvantage of mLSI is that it does not take into account this parameter. In this work, we integrate the exposure time into the mLSI method and provide experimental support of our approach with measurements from an in vitro flow phantom. PMID:21048287

Ramírez-San-Juan, J C; Huang, Y C; Salazar-Hermenegildo, N; Ramos-García, R; Muñoz-Lopez, J; Choi, B

2012-01-01

315

Integration of image exposure time into a modified laser speckle imaging method  

International Nuclear Information System (INIS)

Speckle-based methods have been developed to characterize tissue blood flow and perfusion. One such method, called modified laser speckle imaging (mLSI), enables computation of blood flow maps with relatively high spatial resolution. Although it is known that the sensitivity and noise in LSI measurements depend on image exposure time, a fundamental disadvantage of mLSI is that it does not take into account this parameter. In this work, we integrate the exposure time into the mLSI method and provide experimental support of our approach with measurements from an in vitro flow phantom.

316

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

317

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

318

Design and implementation of a real-time positron imager  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper we are going to present the first real-time S-parameter positron imager. This is a useful tool in solid state technology for mapping the lateral defect types and concentrations on a material sample. This technology has been developed for two major categories of researchers, the first being those that have a focused low energy positron beam and second those that do not. Here we describe the design and implementation of a real-time automated scanning system that rasters a sample s...

Beling, Cd; Fung, S.; Naik, Ps

2004-01-01

319

Bioluminescent assay for serum adenosine deaminase with immobilized bacterial luciferase.  

Science.gov (United States)

We describe a bioluminescence method for measuring adenosine deaminase activity in serum. The method involves use of batchwise enzyme reaction containing adenosine, alpha-ketoglutarate, glutamic dehydrogenase and NADH. The resulting solution is injected to the continuous-flow bioluminescence system. In the system, a bacterial luciferase and NAD(P)H:FMN oxidoreductase are covalently co-immobilized on Sepharose 4B. Carrier solution (pH 6.8) for bioluminescence reaction contains FMN and decanal. The continuous-flow light-emitting system, in which the reactor (flow cell packed with immobilized enzyme) is placed in front of a photomultiplier tube inside a photon counter, is versatile and simple. Concentration and response are linearly related from 1.2 to 92.5 pmol per injection of ammonia. The precision of the method is satisfactory (coefficient of variation 3.9-6.8%). We validated the technique by comparing results with conventional assay method (UV method). Normal values for adenosine deaminase activity of serum ranged from 7.0 to 22.0 U/l in agreement with those obtained by other method. The Sepharose 4B-immobilized enzymes are stable for more than one year. This assay system could be used as a routine clinical laboratory test in the diagnosis of liver damage. PMID:2620450

Oda, K; Yoshida, S; Hirose, S; Takeda, T

1989-10-31

320

Real-time vibration amplitude and phase imaging with heterodyne interferometry and correlation image sensor  

Science.gov (United States)

We propose a new out-of-plane vibration imaging technique for micro-structured solid-state devices such as MEMS (microelectro mechanical systems) microphones and resonators. This technique is based on the longitudinally scanning optical interferometry and an integrated image sensor device which we call the correlation image sensor (CIS). The CIS is able to extract an arbitrary frequency component from time-varying incident light and produce a complex correlation image including amplitude and phase in addition to a conventional intensity image. In heterodyne interferometry of vibrating objects, the vibration information is encoded in several frequency components generated by mutual modulation of longitudinal scan and vibration. In this paper, the combination of newly developed multi-channel CIS and the scanning heterodyne technique enable us to obtain the multiple frequency components simultaneously and reconstruct the vibration amplitude and phase distributions in real time. As an example, vibration modes of a MEMS acoustic sensor are shown to be rconstructed at video rate. A theoretical possiblitiy for the imaging of higher than GHz vibration combining other optical heterodyne techniques is also discussed.

Sato, Seichi; Kurihara, Toru; Ando, Shigeru

2008-08-01

 
 
 
 
321

Time-gated imaging system for tumor diagnosis  

Science.gov (United States)

A novel approach is proposed for fluorescence imaging of biological substrates. Discrimination among the contributions of different fluorophores is achieved in the time domain, taking advantage of the differences in decay times of exogenous versus endogenous fluorescences. The experimental setup relies on an intensified video camera and on a subnanosecond dye laser used for the excitation. The video camera has an electronic shutter that provides exposure times as short as 5 ns. A detailed description of the apparatus is reported with an analysis of performances. The time-gated technique is especially attractive for tumor detection in combination with photosensitizing drugs. Experiments performed on a murine tumor have shown interesting results that make this technique promising for a future application in the clinical diagnosis.

Cubeddu, Rinaldo; Taroni, Paola; Valentini, Gianluca

1993-02-01

322

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

323

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

324

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

325

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.

326

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

327

Real-time FPGA Based Implementation of Color Image Edge Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Color Image edge detection is very basic and important step for many applications such as image segmentation, image analysis, facial analysis, objects identifications/tracking and many others. The main challenge for real-time implementation of color image edge detection is because of high volume of data to be processed (3 times as compared to gray images). This paper describes the real-time implementation of Sobel operator based color image edge detection using FPGA. Sobel operator is chosen ...

Sanjay Singh; Anil Kumar Saini; Ravi Saini

2012-01-01

328

Image-Based Learning Approach Applied to Time Series Forecasting  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish 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

329

Image-Based Learning Approach Applied to Time Series Forecasting  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish 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.

330

Holographic Real-Time Imaging of Standing Waves in Gases  

Science.gov (United States)

Stroboscopic holographic inteferometry has been developed at an advanced undergraduatelevel allowing real-time imaging of standing sound waves in gas filled, closed tube resonators. A heterodyne Mach-Zehnder interferometer was first built by students to show the feasibility of interferometric detection of sound waves in a small cell. In the subsequent holographic study, the laser irradiance is modulated by an acousto-optic cell at frequencies near that of the standing wave, and a video camera records the fringe motion due to sound pressure changes. Fractional fringe shifts are observed for an air filled cell, and multiple fringe shifts are imaged for the case of freon. Sound reflections from the cell ends are easily observed, with non-sinusoidal waveforms dominating at high intensities due to position of resonator harmonics. Presented by Dick Peterson

Peterson, Dick

2011-01-11

331

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

332

Application of Bacterial Bioluminescence To Assess the Efficacy of Fast-Acting Biocides?  

Science.gov (United States)

Traditional microbiological techniques are used to provide reliable data on the rate and extent of kill for a range of biocides. However, such techniques provide very limited data regarding the initial rate of kill of fast-acting biocides over very short time domains. This study describes the application of a recombinant strain of Escherichia coli expressing the Photorhabdus luminescens lux operon as a whole-cell biosensor. Light emission is linked directly to bacterial metabolism; therefore, by monitoring light output, the impact of fast-acting biocides can be assessed. Electrochemically activated solutions (ECASs), bleach, Virkon, and ethanol were assessed at three concentrations (1%, 10%, 80%) in the presence of organic soiling. Over a 2-s time course, 80% ECAS produced the greatest reduction in light output in the absence of organic load but was strongly inhibited by its presence. Eighty percent ethanol outperformed all tested biocides in the presence of organic soil. Bleach and Virkon produced similar reductions in bioluminescence at matched concentrations within the time course of the assay. It was also demonstrated that the assay can be used to rapidly assess the impact of organic soiling. The use of bioluminescent bacteria as whole-cell bioreporters allows assessment of the relative efficacies of fast-acting biocides within milliseconds of application. The assay can be used to investigate activity over short or extended time domains to confirm complete metabolic inhibition of the bioreporter. Moreover, the assay may enable further elucidation of their mechanism of action by allowing the investigation of activity over time domains precluded by traditional microbiology. PMID:21876044

Robinson, Gareth M.; Tonks, Katherine M.; Thorn, Robin M. S.; Reynolds, Darren M.

2011-01-01

333

Application of bacterial bioluminescence to assess the efficacy of fast-acting biocides.  

Science.gov (United States)

Traditional microbiological techniques are used to provide reliable data on the rate and extent of kill for a range of biocides. However, such techniques provide very limited data regarding the initial rate of kill of fast-acting biocides over very short time domains. This study describes the application of a recombinant strain of Escherichia coli expressing the Photorhabdus luminescens lux operon as a whole-cell biosensor. Light emission is linked directly to bacterial metabolism; therefore, by monitoring light output, the impact of fast-acting biocides can be assessed. Electrochemically activated solutions (ECASs), bleach, Virkon, and ethanol were assessed at three concentrations (1%, 10%, 80%) in the presence of organic soiling. Over a 2-s time course, 80% ECAS produced the greatest reduction in light output in the absence of organic load but was strongly inhibited by its presence. Eighty percent ethanol outperformed all tested biocides in the presence of organic soil. Bleach and Virkon produced similar reductions in bioluminescence at matched concentrations within the time course of the assay. It was also demonstrated that the assay can be used to rapidly assess the impact of organic soiling. The use of bioluminescent bacteria as whole-cell bioreporters allows assessment of the relative efficacies of fast-acting biocides within milliseconds of application. The assay can be used to investigate activity over short or extended time domains to confirm complete metabolic inhibition of the bioreporter. Moreover, the assay may enable further elucidation of their mechanism of action by allowing the investigation of activity over time domains precluded by traditional microbiology. PMID:21876044

Robinson, Gareth M; Tonks, Katherine M; Thorn, Robin M S; Reynolds, Darren M

2011-11-01

334

Time Resolved Imaging of Longitudinal Modulations in Intense Beams  

Science.gov (United States)

The longitudinal evolution of high intensity beams is not well understood despite its importance to the success of such applications as free electron lasers and light sources, heavy ion inertial fusion, and high energy colliders. For example any amplification of current modulations in an FEL photoinjector can lead to unwanted coherent synchrotron radiation further downstream in compression chicanes or bends. A significant factor usually neglected is the coupling to the transverse dynamics which can strongly affect the longitudinal evolution. Previous experiments at the University of Maryland have revealed much about the longitudinal physics of space-charge dominated beams by monitoring the evolution of longitudinal perturbations. For the first time, experimental results are presented here which reveal the effect of longitudinal perturbations on the transverse beam distribution, with the aid of several new diagnostics that capture detailed time-resolved density images. A longitudinal modulation of the particle density is deliberately generated at the source, and its evolution is tracked downstream using a number of diagnostics such as current monitors, high-resolution energy analyzers, as well as the transverse imaging devices. The latter consist of a high-resolution 16-bit gated camera coupled with very fast emitters such as prompt optical transition radiation (OTR) from an alumina screen, or fast Phosphor screens with 3-ns time resolution. Simulations using the particle-in-cell code WARP are applied to cross-check the experimental results. These experiments and especially the comparisons to simulation represent significant progress towards understanding the longitudinal physics of intense beams.

Tian, Kai

2007-11-01

335

Time-resolved imaging for the APS linac beams  

International Nuclear Information System (INIS)

The particle-beam imaging diagnostics for the Advanced Photon Source (APS) injector lime have been enhanced by the installation of optical transition radiation (OTR) screens and the use of Ce-doped YAG crystals as beam profile monitors. Both converters have improved spatial resolution and time responses compared to the standard Chromox (Al2O3:Cr) screens used elsewhere in the linac. These enhancements allow us to address the smaller beam sizes (x = 30 microm have been observed with a micropulse bunch length of ? = 2-3 ps using OTR. First results on the lower-emittance rf thermionic gun are briefly discussed

336

Imaging Soft Responsive Surfaces by Time-Resolved Fluorescence Techniques  

Science.gov (United States)

Polymers and proteins induce surface reconstruction within supported lipid bilayers due to electrostatic interactions with lipid headgroups. This introduces structural and dynamical heterogeneity into the lipid bilayer. These issues were investigated using fluorescence techniques. Fluorescence Correlation Spectroscopy (FCS) was used to characterize the mobility distribution of the lipid molecules in the presence of sparsely-adsorbed polymers and proteins. Time-lapsed photography of individual molecules was employed to image domains formed. Two different regions were observed: lipids bound with polymers, whose motion was retarded, and lipids free of adsorbed polymers. The size and mobility of these dynamical domains will be discussed in detail.

Xie, Anne Feng; Jiang Zhao, John; Granick, Steve

2002-03-01

337

Time-Domain Fluorescence Lifetime Imaging Techniques Suitable for Solid-State Imaging Sensor Arrays  

Directory of Open Access Journals (Sweden)

Full Text Available We have successfully demonstrated video-rate CMOS single-photon avalanche diode (SPAD-based cameras for fluorescence lifetime imaging microscopy (FLIM by applying innovative FLIM algorithms. We also review and compare several time-domain techniques and solid-state FLIM systems, and adapt the proposed algorithms for massive CMOS SPAD-based arrays and hardware implementations. The theoretical error equations are derived and their performances are demonstrated on the data obtained from 0.13 ?m CMOS SPAD arrays and the multiple-decay data obtained from scanning PMT systems. In vivo two photon fluorescence lifetime imaging data of FITC-albumin labeled vasculature of a P22 rat carcinosarcoma (BD9 rat window chamber are used to test how different algorithms perform on bi-decay data. The proposed techniques are capable of producing lifetime images with enough contrast.

Robert K. Henderson

2012-05-01

338

Real Time Image Segmentation using watershed algorithm on FPGA  

Directory of Open Access Journals (Sweden)

Full Text Available Watershed transformation is a powerful technique that can be efficiently used for image segmentation. Its use for classifying and grading rice kernels has been discussed followed by its implementation on reconfigurable devices. In this paper, we implement a watershed based segmentation algorithm on a Virtex-6 platform. Themain contribution of this work is the low execution time and minimal internal hardware resource occupation. Watershed has been written in C-code and also in Verilog hardware descriptive language. The Verilog code is synthesized on Virtex-6 Xilinx platform. Execution timing in both these approaches have been analyzed and the hardware approach has been found to be much faster than its software counterpart.

BHUPINDER VERMA,

2011-06-01

339

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

340

Real-time synthetic aperture ultrasonic scroll-imaging system and imaging experiment for nuclear power plant NDT  

International Nuclear Information System (INIS)

The authors discuss their development of a real-time synthetic aperture imaging system which provides a cross sectional image of an object in real-time. They have already confirmed the performance of the system by imaging experiments using the normal-beam method. To confirm the wide applicability of the system, they have carried out imaging experiments with the angle-beam method. They considered four different sound paths for angle-beam SAFT imaging. After calculating sound path lengths, computer simulation and experiments were carried out. It is shown that there were two dominant paths for image reconstruction caused by the directivity of the transducer

 
 
 
 
341

A Double-Threshold Technique for Fast Time-Correspondence Imaging  

CERN Document Server

We present a robust imaging method based on time-correspondence imaging and normalized ghost imaging (GI) that sets two thresholds to select the reference frame exposures for image reconstruction. This double-threshold time-correspondence imaging protocol always gives better quality and signal-to-noise ratio than previous GI schemes, and is insensitive to surrounding noise. Moreover, only simple add and minus operations are required while less data storage space and computing time are consumed, thus faster imaging speeds are attainable. The protocol offers a general approach applicable to all GI techniques, and marks a further step forward towards real-time practical applications of correlation imaging.

Li, Ming-Fei; Liu, Xue-Feng; Yao, Xu-Ri; Luo, Kai-Hong; Fan, Heng; Wu, Ling-An

2013-01-01

342

Comparative bioluminescence dynamics among multiple Armillaria gallica, A. mellea, and A. tabescens genets.  

Science.gov (United States)

Bioluminescence is well known among white-spored species of Basidiomycota including several species of the white-rot wood decay genus Armillaria. Previous work demonstrated consistent differences among A. gallica, A. mellea, and A. tabescens in luminescence magnitude and in luminescence expression relative to environmental stimuli. In the present studies, temporal fluctuations in mycelial luminescence were quantitatively characterized using genets matched for geographical location. All genets derived from rhizomorphs or basdiomata were constitutively luminescent while six of 13 genets originating from mycelial fans were inconsistently luminescent. Using time series of 1000 consecutive measurements over 800 ms intervals, fluctuation patterns had significantly quantifiable structure and were not simply 'white noise'. Fluctuation patterns were qualitatively similar with alternating periods of rapid fluctuation and relative stability, regardless of luminescence magnitude. Anomalous spikes or shifts in luminescence were recorded for several genets suggesting further work to identify the transient stimuli which elicited these altered luminescence patterns. PMID:23537877

Mihail, Jeanne D

2013-03-01

343

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

344

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

345

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

346

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 ecological 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

2013-01-01

347

Inhibitory effect of lipoic acid on firefly luciferase bioluminescence  

International Nuclear Information System (INIS)

Lipoic acid was found to inhibit the firefly luciferin-luciferase reaction. The inhibition is competitive and is the strongest known (Ki 0.026 ± 0.013 ?M) compared with other reported inhibitors. Considering the structure-activity correlations, the mechanism of inhibition may originate from the sulfur atom and carboxyl moiety of lipoic acid giving it structural specificity. Subsequent addition of lipoic acid and nitric oxide accelerated the inhibition in vitro, suggesting that lipoic acid may have a functional role in regulating firefly bioluminescence

348

Toxicity assessment of Hanford Site wastes by bacterial bioluminescence  

International Nuclear Information System (INIS)

This paper examines the toxicity of the nonradioactive component of low-level wastes stored in tanks on the Hanford reservation. The use of a faster, cheaper bioassay to replace the 96 hour fish acute toxicity test is examined. The new bioassay is based on loss of bioluminescence of Photobacter phosphoreum (commonly called Microtox) following exposure to toxic materials. This bioassay is calibrated and compares well to the standard fish acute toxicity test for characterization of Hanford Wastes. 4 refs., 11 figs., 11 tabs

349

Bioluminescence method to evaluate antimicrobial agents against Mycobacterium avium.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Plasmid pLUC10, carrying the firefly luciferase gene, was transformed by electroporation into Mycobacterium avium A5. Bioluminescence production by strain A5(pLUC10), as measured in a microdilution plate luminometer, was approximately 1 relative light unit per 2 x 10(6) viable bacilli, whereas it was 0.0005 relative light unit for an equal number of parental cells. The susceptibility of strain A5(pLUC10) to eight concentrations of each of eight antimicrobial agents was evaluated by the lucife...

Cooksey, R. C.; Morlock, G. P.; Beggs, M.; Crawford, J. T.

1995-01-01

350

Imaging system for obtaining space- and time-resolved plasma images on TMX  

International Nuclear Information System (INIS)

A Reticon 50 x 50 photodiode array camera has been placed on Livermore's Tandem Mirror Experiment to view a 56-cm diameter plasma source of visible, vacuum-ultraviolet, and x-ray photons. The compact camera views the source through a pinhole, filters, a fiber optic coupler, a microchannel plate intensifier (MCPI), and a reducer. The images are digitized (at 3.3 MHz) and stored in a large, high-speed memory that has a capacity of 45 images. A local LSI-11 microprocessor provides immediate processing and display of the data. The data are also stored on floppy disks that can be further processed on the large Livermore Computer System. The temporal resolution is limited by the fastest MCPI gate. The number of images recorded is determined by the read-out time of the Reticon camera (minimum 0.9 msec). The spatial resolution of approximately 1.4 cm is fixed by the geometry and the pinhole of 0.025 cm. Typical high-quality color representation of some plasma images are included

351

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)

352

Reduction of capsule endoscopy reading times by unsupervised image mining.  

Science.gov (United States)

The screening of the small intestine has become painless and easy with wireless capsule endoscopy (WCE) that is a revolutionary, relatively non-invasive imaging technique performed by a wireless swallowable endoscopic capsule transmitting thousands of video frames per examination. The average time required for the visual inspection of a full 8-h WCE video ranges from 45 to 120min, depending on the experience of the examiner. In this paper, we propose a novel approach to WCE reading time reduction by unsupervised mining of video frames. The proposed methodology is based on a data reduction algorithm which is applied according to a novel scheme for the extraction of representative video frames from a full length WCE video. It can be used either as a video summarization or as a video bookmarking tool, providing the comparative advantage of being general, unbounded by the finiteness of a training set. The number of frames extracted is controlled by a parameter that can be tuned automatically. Comprehensive experiments on real WCE videos indicate that a significant reduction in the reading times is feasible. In the case of the WCE videos used this reduction reached 85% without any loss of abnormalities. PMID:19969440

Iakovidis, D K; Tsevas, S; Polydorou, A

2010-09-01

353

Chern numbers hiding in time-of-flight images  

International Nuclear Information System (INIS)

We present a technique for detecting topological invariants--Chern numbers--from time-of-flight images of ultracold atoms. We show that the Chern numbers of integer quantum Hall states of lattice fermions leave their fingerprints in the atoms' momentum distribution. We analytically demonstrate that the number of local maxima in the momentum distribution is equal to the Chern number in two limiting cases, for large hopping anisotropy and in the continuum limit. In addition, our numerical simulations beyond these two limits show that these local maxima persist for a range of parameters. Thus, an everyday observable in cold atom experiments can serve as a useful tool to characterize and visualize quantum states with nontrivial topology.

354

High-resolution imaging with a real-time synthetic aperture ultrasound system: a phantom study  

Science.gov (United States)

It is difficult for ultrasound to image small targets such as breast microcalcifications. Synthetic aperture ultrasound imaging has recently developed as a promising tool to improve the capabilities of medical ultrasound. We use two different tissueequivalent phantoms to study the imaging capabilities of a real-time synthetic aperture ultrasound system for imaging small targets. The InnerVision ultrasound system DAS009 is an investigational system for real-time synthetic aperture ultrasound imaging. We use the system to image the two phantoms, and compare the images with those obtained from clinical scanners Acuson Sequoia 512 and Siemens S2000. Our results show that synthetic aperture ultrasound imaging produces images with higher resolution and less image artifacts than Acuson Sequoia 512 and Siemens S2000. In addition, we study the effects of sound speed on synthetic aperture ultrasound imaging and demonstrate that an accurate sound speed is very important for imaging small targets.

Huang, Lianjie; Labyed, Yassin; Simonetti, Francesco; Williamson, Michael; Rosenberg, Robert; Heintz, Philip; Sandoval, Daniel

2011-03-01

355

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

356

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

357

High Dynamic Range Image Based on Multiple Exposure Time Synthetization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

High dynamic range of illumination may cause serious distortions and otherproblems in viewing and further processing of digital images. In this paper a new tonereproduction preprocessing algorithm is introduced which may help in developing hardly ornon-viewable features and content of the images. The method is based on the synthetizationof multiple exposure images from which the dense part, i.e. regions having the maximumlevel of detail are included in the output image. The resulted high qual...

Yoshifumi Shimodaira; Szilveszter Balogh; Takeshi Hashimoto; András Rövid; Va?rkonyi-ko?czy, Annama?ria R.

2007-01-01

358

Non invasive real-time monitoring of bacterial infection & therapeutic effect of anti-microbials in five mouse models  

Science.gov (United States)

Background & objectives: In vivo imaging system has contributed significantly to the understanding of bacterial infection and efficacy of drugs in animal model. We report five rapid, reproducible, and non invasive murine pulmonary infection, skin and soft tissue infection, sepsis, and meningitis models using Xenogen bioluminescent strains and specialized in vivo imaging system (IVIS). Methods: The progression of bacterial infection in different target organs was evaluated by the photon intensity and target organ bacterial counts. Genetically engineered bioluminescent bacterial strains viz. Staphylococcus aureus Xen 8.1, 29 and 31; Streptococcus pneumoniae Xen 9 and 10 and Pseudomonas aeruginosa Xen-5 were used to induce different target organs infection and were validated with commercially available antibiotics. Results: The lower limit of detection of colony forming unit (cfu) was 1.7-log10 whereas the lower limit of detection of relative light unit (RLU) was 4.2-log10. Recovery of live bacteria from different target organs showed that the bioluminescent signal correlated to the live bacterial count. Interpretation & conclusions: This study demonstrated the real time monitoring and non-invasive analysis of progression of infection and pharmacological efficacy of drugs. These models may be useful for pre-clinical discovery of new antibiotics. PMID:22199109

Barman, Tarani Kanta; Rao, Madhvi; Bhati, Ashish; Kishore, Krishna; Shukla, Gunjan; Kumar, Manoj; Mathur, Tarun; Pandya, Manisha; Upadhyay, Dilip J.

2011-01-01

359

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.

Jensen, Peter Damsgaard; Mohr, Johan Jacob

2011-01-01

360

Real-Time Colour Doppler Imaging for HIFU Therapy Guidance  

Science.gov (United States)

This study is an investigation of interference and blooming artifacts in real-time color Doppler imaging during High-Intensity Focused Ultrasound (HIFU) therapy to improve the field of view (FOV) and distinguish blood vessels from the artifacts. It is hypothesized that the interference and blooming artifacts are caused by incoherent interference between HIFU and imaging signals and inertial cavitation/boiling, respectively. The incoherent interference shifts the tissue velocity estimates toward the Nyquist limits in standard autocorrelation-based estimation. The interference artifact is removed by applying a threshold according to the acceleration in tissue velocity estimation. The effects of inertial cavitation and/or boiling (i.e., broadband spectrum and high amplitude) in the blooming artifact are analyzed by measuring the standard deviation of phase differences, the average difference between adjacent eigenvalues and the average power. From in vivo rabbit experiments, due to its broadband spectrum, while the standard deviation of phase differences in the blooming artifact (0.0959 ± 0.0368 PRF) is significantly increased compared to the normal blood vessels (0.0078 ± 0.0013 PRF), the average difference between adjacent eigenvalues in the blooming artifact (-35.0 ± 8.6 dB) is moderately changed compared to those in the normal blood vessels (i.e., -58.6 ± 4.6 dB). The average power in the blooming artifact (i.e., 48.0 ± 12.7) is also increased compared to the normal blood vessels (i.e., 6.2 ± 1.2). This broadband and high amplitude signature could be utilized to remove this blooming artifact by thresholding after further investigation to distinguish the target blood vessel from the artifact.

Yoo, Yang Mo; Zderic, Vesna; Managuli, Ravi; Vaezy, Shahram; Kim, Yongmin

2005-03-01

 
 
 
 
361

Real-time image acquisition and deblurring for underwater gravel extraction by smartphone  

Directory of Open Access Journals (Sweden)

Full Text Available Gravel size distribution is an important aspect of stream investigation. Using water photography to determine such distribution is a simple and cost-effective approach for gathering instream gravel information. However, good-quality images of underwater gravels in shallow areas are difficult to acquire because of the flow- and wind-induced perturbation at water surface. Thus, two Lucy–Richardson iterations are applied on an averaged image to obtain a deblurred image for gravel extraction. A Matlab code for multi-frame image averaging and image deblurring is implemented on a laptop computer. Underwater gravel images are acquired using a video camera and processed offline. Thus, the usability of the images acquired during field investigation cannot be determined immediately. However, returning to the investigated streams for additional data gathering would be costly, and the cameras may accidentally be dropped into the water. This paper presents multi-frame image averaging and image deblurring smartphone-based approaches for underwater gravel extraction. A waterproof smartphone is used to acquire the images, on which image deblurring is immediately conducted to test whether the images can be used for gravel extraction. The averaged image of using mean-based filter is derived during real-time image acquisition. The deblurred image is derived block-by-block because of limited memory capacity of smartphones. The time consumed for acquiring 1500 frame images with size of 1280 × 720 pixels is approximately 6 min by Sony Xperia smartphones. Image averaging can be performed in real time during image acquisition. Image deblurring is accomplished accurately and is consistent with results of the Matlab code. The processing time for image deblurring is approximately 12 min. A compact system for underwater gravel investigation using smartphones is successfully developed in this study. Image acquisition and deblurring are completed in real time at the investigated fields. Thus, we can immediately test whether the acquired images are usable for gravel extraction, thereby improving investigation efficiency significantly. 

Ming-Fu Chen

2014-02-01

362

The multispectral advanced volumetric real-time imaging compositor for real-time distributed scene generation  

Science.gov (United States)

AMRDEC has developed the Multi-spectral Advanced Volumetric Real-time Imaging Compositor (MAVRIC) prototype for distributed real-time hardware-in-the-loop (HWIL) scene generation. MAVRIC is a dynamic object-based energy conserved scene compositor that can seamlessly convolve distributed scene elements into temporally aligned physicsbased scenes for enhancing existing AMRDEC scene generation codes. The volumetric compositing process accepts input independent of depth order. This real-time compositor framework is built around AMRDEC's ContinuumCore API which provides the common messaging interface leveraging the Neutral Messaging Language (NML) for local, shared memory, reflective memory, network, and remote direct memory access (RDMA) communications and the Joint Signature Image Generator (JSIG) that provides energy conserved scene component interface at each render node. This structure allows for a highly scalable real-time environment capable of rendering individual objects at high fidelity while being considerate of real-time hardware-in-the-loop concerns, such as latency. As such, this system can be scaled to handle highly complex detailed scenes such as urban environments. This architecture provides the basis for common scene generation as it provides disparate scene elements to be calculated by various phenomenology codes and integrated seamlessly into a unified composited environment. This advanced capability is the gateway to higher fidelity scene generation such as ray-tracing. The high speed interconnects using PCI Express and InfiniBand were examined to support distributed scene generation whereby the scene graph, associated phenomenology, and the scene elements can be dynamically distributed across multiple high performance computing assets to maximize system performance.

Morris, Joseph W.; Ballard, Gary H.; Bunfield, Dennis H.; Peddycoart, Thomas E.; Trimble, Darian E.

2011-06-01

363

Ultraweak bioluminescence dynamics and singlet oxygen correlations during injury repair in sweet potato  

Science.gov (United States)

Ultraweak bioluminescence at the level of hundreds of photons per second per square centimeter after cutting injury of sweet potato was investigated. A small emission peak immediate after cutting and a later and higher peak were observed. Selective singlet oxygen inhibitors and sensors have been use to study the contribution of singlet oxygen during the curing process, demonstrating increased presence of singlet oxygen during and after the late bioemission peak. It was confirmed that singlet oxygen has direct contribution to ultraweak bioluminescence but also induces the formation of other exited luminescent species that are responsible for the recorded bioluminescence.

Hossu, Marius; Ma, Lun; Chen, Wei

2011-03-01

364

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

International Nuclear Information System (INIS)

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

365

High Dynamic Range Image Based on Multiple Exposure Time Synthetization  

Directory of Open Access Journals (Sweden)

Full Text Available High dynamic range of illumination may cause serious distortions and otherproblems in viewing and further processing of digital images. In this paper a new tonereproduction preprocessing algorithm is introduced which may help in developing hardly ornon-viewable features and content of the images. The method is based on the synthetizationof multiple exposure images from which the dense part, i.e. regions having the maximumlevel of detail are included in the output image. The resulted high quality HDR image makeseasier the information extraction and effectively supports the further processing of theimage.

Yoshifumi Shimodaira

2007-03-01

366

High resolution, near real-time x-ray video imaging without image intensification  

International Nuclear Information System (INIS)

This paper discusses a type of x-ray camera designed to generate standard RS-170 video output that does not use x-ray or optical image intensifiers. Instead, it employs a very sensitive, very high resolution, CCD sensor which views an x-ray-to-light conversion screen directly through a high speed imaging lens. This new solid state TV camera, which will be described later, has very low readout noise plus unusually high gain which enables it to generate real-time video with incident flux levels typical of many inspection applications. Perhaps more important is an ability to integrate for multiple frame intervals on the chip followed by the output of a standard, RS-170 format video frame containing two balanced interlaced fields. In this integrating mode excellent quality images of low contrast objects can be obtained with only a few tenths of a second integrating intervals. The basic elements of this type of camera will be described and applications discussed where this approach appears to have important advantages over other methods in common use. Also included is an analytical/numerical discussion which supports some of the important points

367

Multimodality Imaging of Tumor Response to Doxil  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Early assessment of tumor responses to chemotherapy could enhance treatment outcomes by ensuring that, from the beginning, treatments meet the individualized needs of patients. In this study, we applied multiple modality molecular imaging techniques to pre-clinical monitoring of early tumor responses to Doxil, focusing on imaging of apoptosis.Methods: Mice bearing UM-SCC-22B human head and neck squamous cancer tumors received either PBS or 1 to 2 doses of Doxil® (doxorubicin HCl liposome injection (10 mg/kg/dose. Bioluminescence signals from an apoptosis-responsive reporter gene were captured for apoptosis evaluation. Tumor metabolism and proliferation were assessed by 18F-FDG and 3'-18F-fluoro-3'-deoxythymidine (18F-FLT positron emission tomography. Diffusion-weighted magnetic resonance imaging (DW-MRI was performed to calculate averaged apparent diffusion coefficients (ADCs for the whole tumor volume. After imaging, tumor samples were collected for histological evaluation, including terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL, anti-CD31, and Ki-67 immunostaining.Results: Two doses of Doxil significantly inhibited tumor growth. Bioluminescence imaging (BLI indicated apoptosis of tumor cells after just 1 dose of Doxil treatment, before apparent tumor shrinkage. 18F-FDG and 18F-FLT PET imaging identified decreased tumor metabolism and proliferation at later time points than those at which BLI indicated apoptosis. MRI measurements of ADC altered in response to Doxil, but only after tumors were treated with 2 doses. Decreased tumor proliferation and increased apoptotic cells were confirmed by changes of Ki-67 index and apoptotic ratio.Conclusion: Our study of tumor responses to different doses of Doxil demonstrated that it is essential to combine apoptosis imaging strategies with imaging of other critical biological or pathological pathways, such as metabolism and proliferation, to improve clinical decision making in apoptosis-related diseases and interventions.

Fan Zhang, Lei Zhu, Gang Liu, Naoki Hida, Guangming Lu, Henry S. Eden, Gang Niu, Xiaoyuan Chen

2011-01-01

368

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

369

Time projection chamber based on micro-pattern detector for neutron time-resolved imaging  

International Nuclear Information System (INIS)

We report on the performance of a micro-Time Projection Chamber (TPC) with a micro-pixel chamber(?-PIC) readout for a time-resolved neutron imaging detector. We developed a ?-TPC with a ?-PIC, which is a type of micro pattern gas detector, and detected three-dimensional (3-D) tracks and the Bragg curves of protons with energies of around 1 MeV. Based on this technique we pointed out that the 3-D measurement of the decay pattern of 3He (n,p (573 keV)) 3H (191 keV) reaction would enable us to distinguish the proton and triton using the energy loss information (Nucl. Instr. and Meth. 517 (2004) 219). Here we present the first result of the 3-D measurement of the decay pattern of 3He reaction with the energy loss information using the ?-TPC

370

Real-time stereo image watermarking using discrete cosine transform and adaptive disparity maps  

Science.gov (United States)

In this paper, a real-time stereo image watermarking scheme using discrete cosine transform(DCT) and disparity map is proposed. That is, a watermark image is embedded into the right image of a stereo image pair in the frequency domain through the conventional DCT operation and disparity information between the watermarked right image and the left image is extracted. And then, the disparity data and the left image are simultaneously transmitted to the recipient through the communication channel. At the receiver, the watermarked right image is reconstructed from the received left image and disparity data through the adaptive matching algorithm and a watermark image is finally extracted from this reconstructed right image through the decoding algorithm. From some experiments by using the stereo image pair captured by the CCD camera and a watermark image of English alphabet 'NRL', it is found that the PSNR of the reconstructed right image through the DCT and adaptive matching algorithm improves to 9.3dB by comparing with those of the reconstructed right images through the conventional pixel-based and block-based matching algorithms. At the same time the PSNR of the watermark image extracted from the reconstructed right image also improve to 7.72dB by comparing with those of the others. These experimental results suggest a possibility of practical implementation of a disparity map-based stereo image watermarking scheme.

Hwang, Dong-Choon; Bae, Kyung-Hoon; Lee, Maeng-Ho; Kim, Eun-Soo

2003-11-01

371

Time-resolved imaging for the APS linac beams.  

Energy Technology Data Exchange (ETDEWEB)

The particle-beam imaging diagnostics for the Advanced Photon Source (APS) injector lime have been enhanced by the installation of optical transition radiation (OTR) screens and the use of Ce-doped YAG crystals as beam profile monitors. Both converters have improved spatial resolution and time responses compared to the standard Chromox (Al{sub 2}O{sub 3}:Cr) screens used elsewhere in the linac. These enhancements allow us to address the smaller beam sizes (< 100 {micro}m) and the critical micropulse bunch length of higher brightness gun sources For the Linac macropulse of 30-ns duration composed of 86 micropulses at S-band frequency intervals, only the OTR mechanism is prompt enough to separate individual micropulses and to allow streak camera measurements of the micropulse averaged bunch length. Tests have been performed at 400 to 625 MeV using the gated DC thermionic gun source. Beam sizes less than {sigma}{sub x} = 30 {micro}m have been observed with a micropulse bunch length of {sigma} = 2-3 ps using OTR. First results on the lower-emittance rf thermionic gun are briefly discussed.

Lumpkin, A. H.

1998-09-29

372

Time resolved ICCD images of an atmospheric pressure plasma jet  

Science.gov (United States)

Plasma bullet is a relatively new plasma source with a large field of potential applications, from biomedical to material processing and surface activation. Our plasma bullet was made of Pyrex glass tube with two electrodes. The width of the electrodes and distance between them was 15 mm. The buffer gas was helium with a flow of 4 slm. High voltage probe was used to obtain voltage waveforms while current waveforms were measured at the resistor. Working frequency was 80 kHz and the power transmitted to the plasma was less than 5 W. Time-resolved images obtained by fast ICCD camera show that the plasma is not continuous, but consisted of small packages of plasma traveling at high speeds. The velocity of these packages outside of the tube is much larger (˜15 km/s) than the speed of the feed gas (˜7 m/s). On the other hand, the velocities in the zone of the electrodes are smaller (˜5 km/s) than the speed of the bullet, but still much higher than the speed of the flowing gas.

Puac, Nevena; Maletic, Dejan; Lazovic, Sasa; Malovic, Gordana; Djordjevic, Antonije; Petrovic, Zoran Lj.

2011-11-01

373

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.

2014-01-01

374

Real-time single-molecule imaging of quantum interference  

Science.gov (United States)

The observation of interference patterns in double-slit experiments with massive particles is generally regarded as the ultimate demonstration of the quantum nature of these objects. Such matter-wave interference has been observed for electrons, neutrons, atoms and molecules and, in contrast to classical physics, quantum interference can be observed when single particles arrive at the detector one by one. The build-up of such patterns in experiments with electrons has been described as the ``most beautiful experiment in physics''. Here, we show how a combination of nanofabrication and nano-imaging allows us to record the full two-dimensional build-up of quantum interference patterns in real time for phthalocyanine molecules and for derivatives of phthalocyanine molecules, which have masses of 514 AMU and 1,298 AMU respectively. A laser-controlled micro-evaporation source was used to produce a beam of molecules with the required intensity and coherence, and the gratings were machined in 10-nm-thick silicon nitride membranes to reduce the effect of van der Waals forces. Wide-field fluorescence microscopy detected the position of each molecule with an accuracy of 10 nm and revealed the build-up of a deterministic ensemble interference pattern from single molecules that arrived stochastically at the detector. In addition to providing this particularly clear demonstration of wave-particle duality, our approach could also be used to study larger molecules and explore the boundary between quantum and classical physics.

Juffmann, Thomas; Milic, Adriana; Müllneritsch, Michael; Asenbaum, Peter; Tsukernik, Alexander; Tüxen, Jens; Mayor, Marcel; Cheshnovsky, Ori; Arndt, Markus

2012-05-01

375

Time-motion analysis of factors affecting patient throughput in an MR imaging center  

International Nuclear Information System (INIS)

The high cost of MR imaging makes efficient use essential. In an effort to increase patient throughput, attention has been focused on shortening the imaging time through reductions in matrix size and number of excitations, and through the use of newer ''fast imaging'' techniques. Less attention has been given to other time-consuming aspects not directly related to imaging time. The authors undertook a time-motion study using a daily log of minute-by-minute activities associated with an MR imaging examination. The times required for the following components of the examination were measured: total study time, examination set-up time, intrastudy physician ''image review'' time, and interstudy patient turnover time. The time lost to claustrophobic reactions, patients' failure to appear for scheduled examinations, unanticipated patient care (sedation, reassurance), and equipment malfunction was also analyzed. Actual imaging time accounted for a relatively small proportion (42%) of total study time. Other factors such as intrastudy image review time (15%), interstudy patient turnover time (11%), and time lost due to claustrophobic reactions, patients' failure to appear for scheduled examinations, and equipment malfunction contributed significantly to the total study time. Simple solutions to these problems can contribute greatly to increasing patient throughput

376

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

International Nuclear Information System (INIS)

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.)

377

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

378

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-ven