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Sample records for improve intravascular optical

  1. Heartbeat OCT: In vivo intravascular megahertz-optical coherence tomography

    NARCIS (Netherlands)

    T. Wang (Tianshi); A.F.H. Pfeiffer (Andreas); E.S. Regar (Eveline); W. Wieser (Wolfgang); H.M.M. van Beusekom (Heleen); C.T. Lancée (Charles); T. Springeling (Tirza); I. Krabbendam (Ilona); A.F.W. van der Steen (Ton); R. Huber (Roman); G. van Soest (Gijs)

    2015-01-01

    textabstractCardiac motion artifacts, non-uniform rotational distortion and undersampling affect the image quality and the diagnostic impact of intravascular optical coherence tomography (IV-OCT). In this study we demonstrate how these limitations of IV-OCT can be addressed by using an imaging syste

  2. Consensus standards for acquisition, measurement, and reporting of intravascular optical coherence tomography studies

    DEFF Research Database (Denmark)

    Tearney, Guillermo J; Regar, Evelyn; Akasaka, Takashi

    2012-01-01

    The purpose of this document is to make the output of the International Working Group for Intravascular Optical Coherence Tomography (IWG-IVOCT) Standardization and Validation available to medical and scientific communities, through a peer-reviewed publication, in the interest of improving the di...

  3. Imminent Cardiac Risk Assessment via Optical Intravascular Biochemical Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, D.; Wetzel, L; Wetzel, M; Lodder, R

    2009-01-01

    Heart disease is by far the biggest killer in the United States, and type II diabetes, which affects 8% of the U.S. population, is on the rise. In many cases, the acute coronary syndrome and/or sudden cardiac death occurs without warning. Atherosclerosis has known behavioral, genetic and dietary risk factors. However, our laboratory studies with animal models and human post-mortem tissue using FT-IR microspectroscopy reveal the chemical microstructure within arteries and in the arterial walls themselves. These include spectra obtained from the aortas of ApoE-/- knockout mice on sucrose and normal diets showing lipid deposition in the former case. Also pre-aneurysm chemical images of knockout mouse aorta walls, and spectra of plaque excised from a living human patient are shown for comparison. In keeping with the theme of the SPEC 2008 conference Spectroscopic Diagnosis of Disease this paper describes the background and potential value of a new catheter-based system to provide in vivo biochemical analysis of plaque in human coronary arteries. We report the following: (1) results of FT-IR microspectroscopy on animal models of vascular disease to illustrate the localized chemical distinctions between pathological and normal tissue, (2) current diagnostic techniques used for risk assessment of patients with potential unstable coronary syndromes, and (3) the advantages and limitations of each of these techniques illustrated with patent care histories, related in the first person, by the physician coauthors. Note that the physician comments clarify the contribution of each diagnostic technique to imminent cardiac risk assessment in a clinical setting, leading to the appreciation of what localized intravascular chemical analysis can contribute as an add-on diagnostic tool. The quality of medical imaging has improved dramatically since the turn of the century. Among clinical non-invasive diagnostic tools, laboratory tests of body fluids, EKG, and physical examination are

  4. Retinal and choroidal intravascular spectral-domain optical coherence tomography

    DEFF Research Database (Denmark)

    Willerslev, Anne; Li, Xiao Qiang; Cordtz, Peter;

    2014-01-01

    flow in the retinal vessels in patients with ocular ischaemic syndrome and central retinal artery occlusion were both associated with lower reflectivity of the blood and an unstructured intravascular SD-OCT profile. Discussion:  This qualitative in vivo study found a characteristically structured SD...

  5. All-optical pulse-echo ultrasound probe for intravascular imaging (Conference Presentation)

    Science.gov (United States)

    Colchester, Richard J.; Noimark, Sacha; Mosse, Charles A.; Zhang, Edward Z.; Beard, Paul C.; Parkin, Ivan P.; Papakonstantinou, Ioannis; Desjardins, Adrien E.

    2016-02-01

    High frequency ultrasound probes such as intravascular ultrasound (IVUS) and intracardiac echocardiography (ICE) catheters can be invaluable for guiding minimally invasive medical procedures in cardiology such as coronary stent placement and ablation. With current-generation ultrasound probes, ultrasound is generated and received electrically. The complexities involved with fabricating these electrical probes can result in high costs that limit their clinical applicability. Additionally, it can be challenging to achieve wide transmission bandwidths and adequate wideband reception sensitivity with small piezoelectric elements. Optical methods for transmitting and receiving ultrasound are emerging as alternatives to their electrical counterparts. They offer several distinguishing advantages, including the potential to generate and detect the broadband ultrasound fields (tens of MHz) required for high resolution imaging. In this study, we developed a miniature, side-looking, pulse-echo ultrasound probe for intravascular imaging, with fibre-optic transmission and reception. The axial resolution was better than 70 microns, and the imaging depth in tissue was greater than 1 cm. Ultrasound transmission was performed by photoacoustic excitation of a carbon nanotube/polydimethylsiloxane composite material; ultrasound reception, with a fibre-optic Fabry-Perot cavity. Ex vivo tissue studies, which included healthy swine tissue and diseased human tissue, demonstrated the strong potential of this technique. To our knowledge, this is the first study to achieve an all-optical pulse-echo ultrasound probe for intravascular imaging. The potential for performing all-optical B-mode imaging (2D and 3D) with virtual arrays of transmit/receive elements, and hybrid imaging with pulse-echo ultrasound and photoacoustic sensing are discussed.

  6. Offline fusion of co-registered intravascular ultrasound and frequency domain optical coherence tomography images for the analysis of human atherosclerotic plaques

    DEFF Research Database (Denmark)

    Räber, Lorenz; Heo, Jung Ho; Radu, Maria D

    2012-01-01

    To demonstrate the feasibility and potential usefulness of an offline fusion of matched optical coherence tomography (OCT) and intravascular ultrasound (IVUS)/virtual histology (IVUS-VH) images.......To demonstrate the feasibility and potential usefulness of an offline fusion of matched optical coherence tomography (OCT) and intravascular ultrasound (IVUS)/virtual histology (IVUS-VH) images....

  7. Improved bioresorbable microporous intravascular stents for gene therapy.

    Science.gov (United States)

    Ye, Y W; Landau, C; Meidell, R S; Willard, J E; Moskowitz, A; Aziz, S; Carlisle, E; Nelson, K; Eberhart, R C

    1996-01-01

    Drug imbibing microporous stents are under development at a number of centers to enhance healing of the arterial wall after balloon coronary angioplasty procedures. The authors improved the mechanical strength and reservoir properties of a biodegradable microporous stent reported to this Society in 1994. A combined tubular/helical coil stent is readily fabricated by flotation/precipitation and casting/ winding techniques. A two stage solvent swelling technique allows precise adjustment of the surface hydrophilic/hydrophobic balance. These developments permit seven-fold improvement in drug capacity without significantly altering mechanical properties. Stents modified in this manner retain tensile and compressive strength and are suitable for remote deployment. Elution kinetics of these modified stents suggest they are suitable for gene delivery. Successful gene transfer and transmural expression have been demonstrated after implantation of stents impregnated with a recombinant adenovirus carrying a nuclear localizing beta-galactosidase reporter gene into rabbit carotid arteries. These studies suggest that surface modified, bioresorbable polymer stents ultimately may be useful adjunctive devices for gene transfer during percutaneous transluminal revascularization.

  8. Optical coherence tomography – near infrared spectroscopy system and catheter for intravascular imaging

    Science.gov (United States)

    Fard, Ali M.; Vacas-Jacques, Paulino; Hamidi, Ehsan; Wang, Hao; Carruth, Robert W.; Gardecki, Joseph A.; Tearney, Guillermo J.

    2013-01-01

    Owing to its superior resolution, intravascular optical coherence tomography (IVOCT) is a promising tool for imaging the microstructure of coronary artery walls. However, IVOCT does not identify chemicals and molecules in the tissue, which is required for a more complete understanding and accurate diagnosis of coronary disease. Here we present a dual-modality imaging system and catheter that uniquely combines IVOCT with diffuse near-infrared spectroscopy (NIRS) in a single dual-modality imaging device for simultaneous acquisition of microstructural and compositional information. As a proof-of-concept demonstration, the device has been used to visualize co-incident microstructural and spectroscopic information obtained from a diseased cadaver human coronary artery. PMID:24514658

  9. Compensation of spectral artifacts in dual-modality intravascular optical coherence tomography and near-infrared spectroscopy (Conference Presentation)

    Science.gov (United States)

    Fard, Ali M.; Gardecki, Joseph A.; Ughi, Giovanni J.; Hyun, Chulho; Tearney, Guillermo J.

    2016-02-01

    Intravascular optical coherence tomography (OCT) is a high-resolution catheter-based imaging method that provides three-dimensional microscopic images of coronary artery in vivo, facilitating coronary artery disease treatment decisions based on detailed morphology. Near-infrared spectroscopy (NIRS) has proven to be a powerful tool for identification of lipid-rich plaques inside the coronary walls. We have recently demonstrated a dual-modality intravascular imaging technology that integrates OCT and NIRS into one imaging catheter using a two-fiber arrangement and a custom-made dual-channel fiber rotary junction. It therefore enables simultaneous acquisition of microstructural and composition information at 100 frames/second for improved diagnosis of coronary lesions. The dual-modality OCT-NIRS system employs a single wavelength-swept light source for both OCT and NIRS modalities. It subsequently uses a high-speed photoreceiver to detect the NIRS spectrum in the time domain. Although use of one light source greatly simplifies the system configuration, such light source exhibits pulse-to-pulse wavelength and intensity variation due to mechanical scanning of the wavelength. This can be in particular problematic for NIRS modality and sacrifices the reliability of the acquired spectra. In order to address this challenge, here we developed a robust data acquisition and processing method that compensates for the spectral variations of the wavelength-swept light source. The proposed method extracts the properties of the light source, i.e., variation period and amplitude from a reference spectrum and subsequently calibrates the NIRS datasets. We have applied this method on datasets obtained from cadaver human coronary arteries using a polygon-scanning (1230-1350nm) OCT system, operating at 100,000 sweeps per second. The results suggest that our algorithm accurately and robustly compensates the spectral variations and visualizes the dual-modality OCT-NIRS images. These

  10. Combined optical coherence tomography and intravascular ultrasound radio frequency data analysis for plaque characterization. Classification accuracy of human coronary plaques in vitro

    NARCIS (Netherlands)

    T.P.M. Goderie; G. van Soest (Gijs); H.M. Garcia-Garcia (Hector); N. Gonzalo (Nieves); S. Koljenovic (Senada); G.J.H.L. Leenders (Geert); F. Mastik (Frits); E.S. Regar (Eveline); J.W. Oosterhuis (Wolter); P.W.J.C. Serruys (Patrick); A.F.W. van der Steen (Ton)

    2010-01-01

    textabstractThis study was performed to characterize coronary plaque types by optical coherence tomography (OCT) and intravascular ultrasound (IVUS) radiofrequency (RF) data analysis, and to investigate the possibility of error reduction by combining these techniques. Intracoronary imaging methods h

  11. Analysis and compensation for the effect of the catheter position on image intensities in intravascular optical coherence tomography

    Science.gov (United States)

    Liu, Shengnan; Eggermont, Jeroen; Wolterbeek, Ron; Broersen, Alexander; Busk, Carol A. G. R.; Precht, Helle; Lelieveldt, Boudewijn P. F.; Dijkstra, Jouke

    2016-12-01

    Intravascular optical coherence tomography (IVOCT) is an imaging technique that is used to analyze the underlying cause of cardiovascular disease. Because a catheter is used during imaging, the intensities can be affected by the catheter position. This work aims to analyze the effect of the catheter position on IVOCT image intensities and to propose a compensation method to minimize this effect in order to improve the visualization and the automatic analysis of IVOCT images. The effect of catheter position is modeled with respect to the distance between the catheter and the arterial wall (distance-dependent factor) and the incident angle onto the arterial wall (angle-dependent factor). A light transmission model incorporating both factors is introduced. On the basis of this model, the interaction effect of both factors is estimated with a hierarchical multivariant linear regression model. Statistical analysis shows that IVOCT intensities are significantly affected by both factors with p<0.001, as either aspect increases the intensity decreases. This effect differs for different pullbacks. The regression results were used to compensate for this effect. Experiments show that the proposed compensation method can improve the performance of the automatic bioresorbable vascular scaffold strut detection.

  12. Validating Intravascular Imaging with Serial Optical Coherence Tomography and Confocal Fluorescence Microscopy

    Science.gov (United States)

    Tardif, Pier-Luc; Bertrand, Marie-Jeanne; Abran, Maxime; Castonguay, Alexandre; Lefebvre, Joël; Stähli, Barbara E.; Merlet, Nolwenn; Mihalache-Avram, Teodora; Geoffroy, Pascale; Mecteau, Mélanie; Busseuil, David; Ni, Feng; Abulrob, Abedelnasser; Rhéaume, Éric; L’Allier, Philippe; Tardif, Jean-Claude; Lesage, Frédéric

    2016-01-01

    Atherosclerotic cardiovascular diseases are characterized by the formation of a plaque in the arterial wall. Intravascular ultrasound (IVUS) provides high-resolution images allowing delineation of atherosclerotic plaques. When combined with near infrared fluorescence (NIRF), the plaque can also be studied at a molecular level with a large variety of biomarkers. In this work, we present a system enabling automated volumetric histology imaging of excised aortas that can spatially correlate results with combined IVUS/NIRF imaging of lipid-rich atheroma in cholesterol-fed rabbits. Pullbacks in the rabbit aortas were performed with a dual modality IVUS/NIRF catheter developed by our group. Ex vivo three-dimensional (3D) histology was performed combining optical coherence tomography (OCT) and confocal fluorescence microscopy, providing high-resolution anatomical and molecular information, respectively, to validate in vivo findings. The microscope was combined with a serial slicer allowing for the imaging of the whole vessel automatically. Colocalization of in vivo and ex vivo results is demonstrated. Slices can then be recovered to be tested in conventional histology. PMID:27983695

  13. Validating Intravascular Imaging with Serial Optical Coherence Tomography and Confocal Fluorescence Microscopy

    Directory of Open Access Journals (Sweden)

    Pier-Luc Tardif

    2016-12-01

    Full Text Available Atherosclerotic cardiovascular diseases are characterized by the formation of a plaque in the arterial wall. Intravascular ultrasound (IVUS provides high-resolution images allowing delineation of atherosclerotic plaques. When combined with near infrared fluorescence (NIRF, the plaque can also be studied at a molecular level with a large variety of biomarkers. In this work, we present a system enabling automated volumetric histology imaging of excised aortas that can spatially correlate results with combined IVUS/NIRF imaging of lipid-rich atheroma in cholesterol-fed rabbits. Pullbacks in the rabbit aortas were performed with a dual modality IVUS/NIRF catheter developed by our group. Ex vivo three-dimensional (3D histology was performed combining optical coherence tomography (OCT and confocal fluorescence microscopy, providing high-resolution anatomical and molecular information, respectively, to validate in vivo findings. The microscope was combined with a serial slicer allowing for the imaging of the whole vessel automatically. Colocalization of in vivo and ex vivo results is demonstrated. Slices can then be recovered to be tested in conventional histology.

  14. Intravascular optical coherence tomography to characterize tissue deformation during angioplasty: preliminary experiments with artery phantoms

    Science.gov (United States)

    Azarnoush, Hamed; Vergnole, Sébastien; Pazos, Valérie; Bisaillon, Charles-Étienne; Boulet, Benoit; Lamouche, Guy

    2012-09-01

    We explored the potential of intravascular optical coherence tomography (IVOCT) to assess deformation during angioplasty balloon inflation. Using a semi-compliant balloon and artery phantoms, we considered two experimental scenarios. The goal for the first scenario was to investigate if variation in the elasticity of the structure surrounding the balloon could be sensed by IVOCT monitoring. In this scenario, we used three single-layer phantoms with various mechanical properties. Image analysis was performed to extract the inner and outer diameters of the phantoms at various pressures. The goal for the second scenario was twofold. First, we investigated the IVOCT capability to monitor a more complex balloon inflation process. The balloon was in a folded state prior to inflation. This allowed studying two stages of deformation: during balloon unfolding and during balloon expansion. Second, we investigated IVOCT capability to monitor the deformation in a three-layer phantom used to better mimic a true artery. So, not only were the IVOCT images processed to provide the inner and outer diameters of the phantom, but the layer thicknesses were also determined. In both scenarios, IVOCT monitoring revealed to be very efficient in providing relevant information about the phantom deformation during balloon inflation.

  15. Intravascular optical coherence tomography light scattering artifacts: merry-go-rounding, blooming, and ghost struts

    Science.gov (United States)

    Mancuso, J. Jacob; Halaney, David L.; Elahi, Sahar; Ho, Derek; Wang, Tianyi; Ouyang, Yongjian; Dijkstra, Jouke; Milner, Thomas E.; Feldman, Marc D.

    2014-12-01

    We sought to elucidate the mechanisms underlying two common intravascular optical coherence tomography (IV-OCT) artifacts that occur when imaging metallic stents: "merry-go-rounding" (MGR), which is an increase in strut arc length (SAL), and "blooming," which is an increase in the strut reflection thickness (blooming thickness). Due to uncontrollable variables that occur in vivo, we performed an in vitro assessment of MGR and blooming in stented vessel phantoms. Using Xience V and Driver stents, we examined the effects of catheter offset, intimal strut coverage, and residual blood on SAL and blooming thickness in IV-OCT images. Catheter offset and strut coverage both caused minor MGR, while the greatest MGR effect resulted from light scattering by residual blood in the vessel lumen, with 1% hematocrit (Hct) causing a more than fourfold increase in SAL compared with saline (pResidual blood also resulted in blooming, with blooming thickness more than doubling when imaged in 0.5% Hct compared with saline (presidual blood in the imaging field, is the predominant cause of MGR. Light scattering also results in blooming, and a newly described artifact, three-dimensional-MGR, which results in "ghost struts" in B-scans.

  16. First clinical pilot study with intravascular polarization sensitive optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Villiger, Martin; Karanasos, Antonios; Ren, Jian; Lippok, Norman; Shishkov, Milen; Daemen, Joost; Van Mieghem, Nicolas; Diletti, Roberto; Valgimigli, Marco; van Geuns, Robert-Jan; de Jaegere, Peter; Zijlstra, Felix; van Soest, Gijs; Nadkarni, Seemantini; Regar, Evelyn; Bouma, Brett E.

    2016-02-01

    Polarization sensitive (PS) OCT measures the polarization states of the light backscattered by tissue and provides measures of tissue birefringence and depolarization in addition to the structural OCT signal. Ex vivo studies have demonstrated that birefringence is increased in tissue rich in collagen and with elevated smooth muscle cell content. Preliminary data further suggests that depolarization can identify regions of macrophage infiltration, lipid, and irregularly arranged collagen fibers. These are important aspects of the mechanical integrity and vulnerability of atherosclerotic plaques. To evaluate the potential of PS-OCT in the clinical setting, we combined our custom PS-OCT system with commercially available OCT catheters (Fastview, Terumo Corporation) and performed a pilot study in 30 patients, scheduled to undergo percutaneous coronary intervention (PCI) on the grounds of stable or unstable angina. A total of 82 pullbacks in 39 vessels were performed, either in the native coronary arteries or post procedure. Comparing consecutive pullbacks of the same coronary artery, we found excellent agreement between the polarization features in the repeat pullbacks, validating the repeatability and robustness of PS-OCT in the clinical in vivo setting. In addition we observed that the birefringence and depolarization features vary significantly across lesions with identical structural OCT appearance, suggesting morphological subtypes. This first human pilot study proved the feasibility and robustness of intravascular PS-OCT. PS-OCT achieves improved tissue characterization and may help in identifying high-risk plaques, with the potential to ultimately improve risk stratification and help guiding PCI.

  17. Characterization of coronary plaques with combined use of intravascular ultrasound, virtual histology and optical coherence tomography

    Directory of Open Access Journals (Sweden)

    José Calabuig

    2010-09-01

    Full Text Available According to post-mortem studies, luminal thrombosis occurs from plaque rupture, erosion and calcified nodules. In vivo studies have found thin cap fibroatheroma (TCFA as the main vulnerable lesion, prone to rupture. Few data about other post-mortem lesions have been reported in vivo. Our main objective is to characterize in vivo the coronary plaques with intravascular ultrasound-virtual histology (IVUS-VH and optical coherence tomography (OCT, in order to detect not only thin cap fibroatheroma (TCFA, but also other possible vulnerable lesions. The secondary objective is to correlate these findings with clinical and analytical data. Twenty-five patients (18 stable submitted to coronary angiography were included in this pilot study. After angiography, the three vessels were studied (when possible with IVUS-VH and OCT. Plaque characteristics were correlated with clinical and analytical data. Forty-six lesions were analyzed. IVUS-VH detected significant necrotic core in 15 (3 were definite TCFA. OCT detected TCFA in 10 lesions, erosion in 6, thrombus in 5 and calcified nodule in 8. Possible vulnerable lesion was found in 61% of stable and 57% of unstable patients. Erosions and calcified nodules were only found in stable patients. Those with significant necrotic core had higher body mass index (P=0.016, higher levels of hs-CRP (P=0.019 and triglycerides (P=0.040. The higher the levels of hs-CRP, the larger the size of the necrotic core (r=0.69, P=0.003. Lesions with characteristics of vulnerability were detected by IVUS-VH and OCT in more than 50% of stable and unstable coronary patients. A significant necrotic core was mainly correlated with

  18. Three-dimensional quantitative coronary angiography and the registration with intravascular ultrasound and optical coherence tomography

    NARCIS (Netherlands)

    Tu, Shengxian

    2012-01-01

    This thesis proposes several new algorithms including X-ray angiographic image enhancement, three-dimensional (3D) angiographic reconstruction, angiographic overlap prediction, and the co-registration of X-ray angiography with intracoronary imaging devices, such as intravascular ultrasound (IVUS) an

  19. Intravascular clearance of disseminating Cryptococcus neoformans in the brain can be improved by enhancing neutrophil recruitment in mice.

    Science.gov (United States)

    Sun, Donglei; Zhang, Mingshun; Liu, Gongguan; Wu, Hui; Li, Chang; Zhou, Hong; Zhang, Xiquan; Shi, Meiqing

    2016-07-01

    Extrapulmonary dissemination of Cryptococcus neoformans (C. neoformans) is one of the most critical steps in the development of meningoencephalitis. Here, we report that clearance of the disseminating C. neoformans occurs within the brain microvasculature. Interestingly, the efficiency of the intravascular clearance in the brain is reduced compared to that in the lung. Intravascular clearance is mainly mediated by neutrophils, and complement C5a receptor signaling is crucial for mediating neutrophil recruitment in the vasculature. C. neoformans stimulated actin polymerization of neutrophils is critically involved in their recruitment to the lung, which is associated with the unique vascular structure detected in the lung. The relatively lower efficiency of fungal clearance in the brain vasculature correlates with less efficient recruitment of neutrophils. Accordingly, intravascular clearance of C. neoformans in the brain could be remarkably improved by increasing the recruitment of neutrophils. We conclude that neutrophils have the ability to eliminate C. neoformans arrested in the vasculature. However, insufficient recruitment of neutrophils limited the optimal clearance of this microorganism in the brain. These results imply that a therapeutic strategy aimed at enhancing the accumulation of neutrophils could help prevent cryptococcal meningoencephalitis.

  20. Intravascular ultrasound

    Science.gov (United States)

    IVUS; Ultrasound - coronary artery; Endovascular ultrasound; Intravascular echocardiography ... A tiny ultrasound wand is attached to the top of a thin tube. This tube is called a catheter. The catheter ...

  1. Fully integrated optical coherence tomography, ultrasound, and indocyanine green-based fluorescence tri-modality system for intravascular imaging.

    Science.gov (United States)

    Li, Yan; Jing, Joseph; Qu, Yueqiao; Miao, Yusi; Zhang, Buyun; Ma, Teng; Yu, Mingyue; Zhou, Qifa; Chen, Zhongping

    2017-02-01

    We present a tri-modality imaging system and fully integrated tri-modality probe for intravascular imaging. The tri-modality imaging system is able to simultaneously acquire optical coherence tomography (OCT), ultrasound (US), and fluorescence imaging. Moreover, for fluorescence imaging, we used the FDA-approved indocyanine green (ICG) dye as the contrast agent to target lipid-loaded macrophages. We conducted imaging from a male New Zealand white rabbit to evaluate the performance of the tri-modality system. In addition, tri-modality images of rabbit aortas were correlated with hematoxylin and eosin (H&E) histology to check the measurement accuracy. The fully integrated miniature tri-modality probe, together with the use of ICG dye suggest that the system is of great potential for providing a more accurate assessment of vulnerable plaques in clinical applications.

  2. Head to head comparison of optical coherence tomography, intravascular ultrasound echogenicity and virtual histology for the detection of changes in polymeric struts over time

    DEFF Research Database (Denmark)

    Brugaletta, Salvatore; Gomez-Lara, Josep; Bruining, Nico

    2012-01-01

    To analyse and to compare the changes in the various optical coherence tomography (OCT), echogenicity and intravascular ultrasound virtual histology (VH) of the everolimus-eluting bioresorbable scaffold (ABSORB) degradation parameters during the first 12 months after ABSORB implantation. In the A......To analyse and to compare the changes in the various optical coherence tomography (OCT), echogenicity and intravascular ultrasound virtual histology (VH) of the everolimus-eluting bioresorbable scaffold (ABSORB) degradation parameters during the first 12 months after ABSORB implantation....... In the ABSORB study, changes in the appearance of the ABSORB scaffold were monitored over time using various intracoronary imaging modalities. The scaffold struts exhibited a progressive change in their black core area by OCT, in their ultrasound derived grey level intensity quantified by echogenicity...

  3. Relation between baseline plaque features and subsequent coronary artery remodeling determined by optical coherence tomography and intravascular ultrasound.

    Science.gov (United States)

    Xie, Zulong; Dong, Nana; Sun, Rong; Liu, Xinxin; Gu, Xia; Sun, Yong; Du, Hongwei; Dai, Jiannan; Liu, Youbin; Hou, Jingbo; Tian, Jinwei; Yu, Bo

    2017-01-17

    Atherosclerosis often leads to myocardial infarction and stroke. We examined the influence of baseline plaque characteristics on subsequent vascular remodeling in response to changes in plaque size. Using optical coherence tomography (OCT) and intravascular ultrasound (IVUS), we examined 213 plaques from 138 patients with acute coronary syndrome at baseline and repeated IVUS at the 12-month follow-up. The change in external elastic membrane (EEM) area for each 1 mm2 change in plaque area (i.e., the slope of the regression line) was calculated as a measure of vascular remodeling capacity. In plaques with static positive remodeling, the slope was smaller than in plaques without static positive remodeling. In addition, the slope of the regression line for lesions with a large plaque burden was much smaller than that for lesions with a small plaque burden. Multivariate linear regression analysis showed that diabetes, calcification and static positive remodeling were inversely and independently associated with the level of change in EEM area/change in plaque area. Lesions with a large plaque burden, calcifications or static positive remodeling had less remodeling capacity, and calcification and static positive remodeling were independent predictors of reduced subsequent remodeling. Therefore, calcifications and static positive remodeling could be used as morphological biomarkers to predict decreased subsequent arterial remodeling.

  4. A new method for real-time co-registration of 3D coronary angiography and intravascular ultrasound or optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Carlier, Stéphane, E-mail: sgcarlier@hotmail.com [Department of Cardiology, Universitair Ziekenhuis - UZ Brussel, Brussels (Belgium); Department of Cardiology, Erasme University Hospital, Université Libre de Bruxelles (ULB), Brussels (Belgium); Didday, Rich [INDEC Medical Systems Inc., Santa Clara, CA (United States); Slots, Tristan [Pie Medical Imaging BV, Maastricht (Netherlands); Kayaert, Peter; Sonck, Jeroen [Department of Cardiology, Universitair Ziekenhuis - UZ Brussel, Brussels (Belgium); El-Mourad, Mike; Preumont, Nicolas [Department of Cardiology, Erasme University Hospital, Université Libre de Bruxelles (ULB), Brussels (Belgium); Schoors, Dany; Van Camp, Guy [Department of Cardiology, Universitair Ziekenhuis - UZ Brussel, Brussels (Belgium)

    2014-06-15

    We present a new clinically practical method for online co-registration of 3D quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) or optical coherence tomography (OCT). The workflow is based on two modified commercially available software packages. Reconstruction steps are explained and compared to previously available methods. The feasibility for different clinical scenarios is illustrated. The co-registration appears accurate, robust and induced a minimal delay on the normal cath lab activities. This new method is based on the 3D angiographic reconstruction of the catheter path and does not require operator’s identification of landmarks to establish the image synchronization.

  5. Optical assessment of intravascular and intracellular parameters related to tissue viability

    Science.gov (United States)

    Mayevsky, Avraham; Sherman, Efrat; Cohen-Kashi, Meir; Dekel, Nava; Pewzner, Eliyahu

    2007-02-01

    Tissue viability represents the balance between O II supply and demand. In our previous paper (Mayevsky et al; Proc.SPIE 6083 : z1-z10, 2006) the HbO II was added to the multiparametric tissue spectroscope (Mayevsky et al J.Biomedical Optics 9:1028-1045,2004). This parameter provides relative values of microcirculatory blood oxygenation (MC-HbO II) evaluated by the 2 wavelength reflectometry principle. The advantage of this approach as compared to pulse oximetry is that the measurement is not dependent of the existence of the pulse of the heart. Also in the MC-HbO II the information is collected from small vessels providing O II to the mitochondria as compared to the pulse oximeter indicating blood oxygenation by the respiratory and cardiovascular systems. In the present study we compared the level of blood oxygenation measured by the pulse oximeter to that measured by the CritiView in the brain exposed to various systemic and localized perturbations of O II supply or demand. We exposed gerbils to anoxia, hypoxia, ischemia and terminal anoxia. In addition we measured mitochondrial NADH (surface fluorometry), tissue reflectance, tissue blood flow (laser Doppler flowmetry) from the same site of MC-HbO II measurement. A clear connection was found between the two blood oxygenation parameters only when systemic perturbations were used (anoxia, hypoxia and terminal anoxia). Under local events (ischemia) the MC-HbO II was responsive while the systemic oxygenation was unchanged. We concluded that MC-HbO II has a significant value in interpretation of tissue energy metabolism under pathophysiological conditions.

  6. Automated detection of vessel lumen and stent struts in intravascular optical coherence tomography to evaluate stent apposition and neointimal coverage

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Hyeong Soo; Kim, Chang-Soo; Yoo, Hongki, E-mail: kjwmm@korea.ac.kr, E-mail: hyoo@hanyang.ac.kr [Department of Biomedical Engineering, Hanyang University, Seoul 04763 (Korea, Republic of); Lee, Jae Joong; Song, Joon Woo; Kim, Jin Won, E-mail: kjwmm@korea.ac.kr, E-mail: hyoo@hanyang.ac.kr [Division of Interventional Cardiology, Cardiovascular Center, Korea University Guro Hospital, Seoul 08308 (Korea, Republic of)

    2016-04-15

    Purpose: Intravascular optical coherence tomography (IV-OCT) is a high-resolution imaging method used to visualize the microstructure of arterial walls in vivo. IV-OCT enables the clinician to clearly observe and accurately measure stent apposition and neointimal coverage of coronary stents, which are associated with side effects such as in-stent thrombosis. In this study, the authors present an algorithm for quantifying stent apposition and neointimal coverage by automatically detecting lumen contours and stent struts in IV-OCT images. Methods: The algorithm utilizes OCT intensity images and their first and second gradient images along the axial direction to detect lumen contours and stent strut candidates. These stent strut candidates are classified into true and false stent struts based on their features, using an artificial neural network with one hidden layer and ten nodes. After segmentation, either the protrusion distance (PD) or neointimal thickness (NT) for each strut is measured automatically. In randomly selected image sets covering a large variety of clinical scenarios, the results of the algorithm were compared to those of manual segmentation by IV-OCT readers. Results: Stent strut detection showed a 96.5% positive predictive value and a 92.9% true positive rate. In addition, case-by-case validation also showed comparable accuracy for most cases. High correlation coefficients (R > 0.99) were observed for PD and NT between the algorithmic and the manual results, showing little bias (0.20 and 0.46 μm, respectively) and a narrow range of limits of agreement (36 and 54 μm, respectively). In addition, the algorithm worked well in various clinical scenarios and even in cases with a low level of stent malapposition and neointimal coverage. Conclusions: The presented automatic algorithm enables robust and fast detection of lumen contours and stent struts and provides quantitative measurements of PD and NT. In addition, the algorithm was validated using

  7. Continued improvement of clinical outcome and cost effectiveness following intravascular ultrasound guided PCI: insights from a prospective, randomised study

    Science.gov (United States)

    Gaster, A L; Slothuus Skjoldborg, U; Larsen, J; Korsholm, L; von Birgelen, C; Jensen, S; Thayssen, P; Pedersen, K E; Haghfelt, T H

    2003-01-01

    Objective: To investigate in a prospective randomised study both long term clinical effects and cost effectiveness of percutaneous coronary interventions (PCI) with or without intravascular ultrasound (IVUS) guidance. Methods: 108 male patients with stable angina referred for PCI of a significant coronary lesion were randomly assigned to IVUS guided PCI or conventional PCI. Individual accumulated costs of the entire follow up period were calculated and compared in the randomisation groups. Effectiveness of treatment was measured by freedom from major adverse cardiac events. Results: Cost effectiveness of IVUS guided PCI that was noted at six months was maintained and even accentuated at long term follow up (median 2.5 years). The cumulated cost level was found to be lower for the IVUS guided group, with a cumulated cost of &163 672 in the IVUS guided group versus &313 706 in the coronary angiography group (p = 0.01). Throughout the study, mean cost per day was lower in the IVUS guided PCI group (&2.7 v &5.2; p = 0.01). In the IVUS group, 78% were free from major adverse cardiac events versus 59% in the coronary angiography group (p = 0.04) with an odds ratio of 2.5 in favour of IVUS guidance. Conclusion: IVUS guidance results in continued improvement of long term clinical outcome and cost effectiveness. The results of this study suggest that IVUS guidance may be used more liberally in PCI. PMID:12923023

  8. Improved Optical Keyboard

    Science.gov (United States)

    Jamieson, R. S.

    1985-01-01

    Optical keyboard surfaces used in typewriters, computer terminals, and telephone inexpensively fabricated using stack of printed-circuit cards set in laminate. Internal laminations carry all illuminating and sensing light conductors to keys.

  9. Improved optically driven microrotors

    Science.gov (United States)

    Asavei, Theodor; Loke, Vincent L. Y.; Nieminen, Timo A.; Heckenberg, Norman R.; Rubinsztein-Dunlop, Halina

    2008-08-01

    Two-photon polymerization of optically curing resins is a powerful method to fabricate micron sized objects which can be used as tools to measure properties at small scales. These microdevices can be driven by means of externally applied focused laser beams (optical tweezers) through angular momentum exchange, giving rise to a net torque. The advantage of the optical drive is that no contact is required, therefore making the microdevices suited to non-invasive biological applications. The fabrication method is versatile and allows building objects of any 3D shape. We discuss the design and modelling of various optically driven rotors. In particular, we consider fabrication of microspheres with an internal shape birefringence in order to obtain rotation in an optical trap. The reason for fabricating this type of object is that they are well-suited for studies of mechanical properties of single biomolecules such as the torsional stiffness of DNA or torque generated by molecular motors. The microspheres fabricated are able to transduce torques of 2000 pNnm with optical powers of 500 mW and could be rotated with frequencies up to 40 Hz in circularly polarized light.

  10. The qualitative assessment of biodegradable coronary stents with the use of intravascular ultrasound, optical coherence tomography and histology

    OpenAIRE

    Burcu GÜL

    2014-01-01

    Percutaneous coronary intervention (PCI) is the most common treatment for coronary artery disease (CAD). The first form of PCI introduced was balloon angioplasty. After that, the advent of coronary stents (tubular wire mesh for intravascular mechanical support) led to a new era in interventional cardiology. Through the implantation of bare metal stents (BMS), all three limitations of balloon angioplasty – coronary artery dissection, elastic recoil and negative remodelling – are prevented. Unf...

  11. Back-to-back optical coherence tomography-ultrasound probe for co-registered three-dimensional intravascular imaging with real-time display

    Science.gov (United States)

    Li, Jiawen; Ma, Teng; Jing, Joseph; Zhang, Jun; Patel, Pranav M.; Shung, K. Kirk; Zhou, Qifa; Chen, Zhongping

    2014-03-01

    We have developed a novel integrated optical coherence tomography (OCT)-intravascular ultrasound (IVUS) probe, with a 1.5 mm-long rigid-part and 0.9 mm outer diameter, for real-time intracoronary imaging of atherosclerotic plaques and guiding interventional procedures. By placing the OCT ball lens and IVUS 45MHz single element transducer back-to-back at the same axial position, this probe can provide automatically co-registered, co-axial OCT-IVUS imaging. To demonstrate its capability, 3D OCT-IVUS imaging of a pig's coronary artery in real-time displayed in polar coordinates, as well as images of two major types of advanced plaques in human cadaver coronary segments, was obtained using this probe and our upgraded system. Histology validation is also presented.

  12. Mapping intravascular ultrasound controversies in interventional cardiology practice.

    Directory of Open Access Journals (Sweden)

    David Maresca

    Full Text Available Intravascular ultrasound is a catheter-based imaging modality that was developed to investigate the condition of coronary arteries and assess the vulnerability of coronary atherosclerotic plaques in particular. Since its introduction in the clinic 20 years ago, use of intravascular ultrasound innovation has been relatively limited. Intravascular ultrasound remains a niche technology; its clinical practice did not vastly expand, except in Japan, where intravascular ultrasound is an appraised tool for guiding percutaneous coronary interventions. In this qualitative research study, we follow scholarship on the sociology of innovation in exploring both the current adoption practices and perspectives on the future of intravascular ultrasound. We conducted a survey of biomedical experts with experience in the technology, the practice, and the commercialization of intravascular ultrasound. The collected information enabled us to map intravascular ultrasound controversies as well as to outline the dynamics of the international network of experts that generates intravascular ultrasound innovations and uses intravascular ultrasound technologies. While the technology is praised for its capacity to measure coronary atherosclerotic plaque morphology and is steadily used in clinical research, the lack of demonstrated benefits of intravascular ultrasound guided coronary interventions emerges as the strongest factor that prevents its expansion. Furthermore, most of the controversies identified were external to intravascular ultrasound technology itself, meaning that decision making at the industrial, financial and regulatory levels are likely to determine the future of intravascular ultrasound. In light of opinions from the responding experts', a wider adoption of intravascular ultrasound as a stand-alone imaging modality seems rather uncertain, but the appeal for this technology may be renewed by improving image quality and through combination with

  13. Disseminated intravascular coagulation (DIC)

    Science.gov (United States)

    ... Jr, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice . 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 141. Thachil J, Toh CH. Current concepts in the management of disseminated intravascular coagulation. Thromb Res . 2012;129 ...

  14. Intravascular malignant lymphomatosis

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Duverneuil, N.; Lafitte, F.; Chiras, J. [Service de Neuroradiologie Charcot, Batiment Babinski, Hopital de la Salpetriere, 75013 Paris (France); Mokhtari, K. [Service de Neuropathologie, Hopital de la Salpetriere, 75013 Paris (France); Behin, A.; Hoang-Xuan, K. [Departement de Neurologie, Hopital de la Salpetriere, 75013 Paris (France)

    2002-09-01

    Intravascular malignant lymphomatosis is a rare and probably often overlooked disease characterised by massive intravascular proliferation of lymphoid cells, usually with a poor prognosis. CT and MRI appearances are nonspecific; the most suggestive finding being both asymmetrical, bilateral, contrast enhancing high-signal areas on T2 weighting and infarct-like lesions of the cortex and basal ganglia. We report two patients with previously unreported dural and spinal cord involvement. (orig.)

  15. In Vivo Diagnosis of Plaque Erosion and Calcified Nodule in Patients with Acute Coronary Syndrome by Intravascular Optical Coherence Tomography

    Science.gov (United States)

    Jia, Haibo; Abtahian, Farhad; Aguirre, Aaron D; Lee, Stephen; Chia, Stanley; Lowe, Harry; Kato, Koji; Yonetsu, Taishi; Vergallo, Rocco; Hu, Sining; Tian, Jinwei; Lee, Hang; Park, Seung-Jung; Jang, Yang-Soo; Raffel, Owen C.; Mizuno, Kyoichi; Uemura, Shiro; Itoh, Tomonori; Kakuta, Tsunekazu; Choi, So-Yeon; Dauerman, Harold L.; Prasad, Abhiram; Toma, Catalin; McNulty, Iris; Zhang, Shaosong; Yu, Bo; Fuster, Valentine; Narula, Jagat; Virmani, Renu; Jang, Ik-Kyung

    2013-01-01

    Objectives To characterize the morphological features of plaque erosion and calcified nodule in patients with acute coronary syndrome (ACS) by optical coherence tomography (OCT). Background Plaque erosion and calcified nodule have not been systematically investigated in vivo. Methods One hundred and twenty-six patients with ACS who had undergone pre-intervention OCT imaging were included. The culprit lesions were classified as plaque rupture (PR), erosion (OCT-erosion), calcified nodule (OCT-CN), or others using a new set of diagnostic criteria for OCT. Results The incidences of PR, OCT-erosion, and OCT-CN were 43.7%, 31.0%, and 7.9%, respectively. Patients with OCT-erosion were the youngest compared with those with PR and OCT-CN (53.8±13.1 years vs. 60.6±11.5 years, 65.1±5.0 years, p=0.005). Compared with patients with PR, presentation with non-ST-segment elevation ACS (NSTE-ACS) was more common in patients with OCT-erosion (61.5% vs. 29.1%, p=0.008) and OCT-CN (100% vs. 29.1%, perosion had a lower frequency of lipid plaque (43.6% vs. 100%, perosion followed by OCT-CN and PR (55.4±14.7% vs. 66.1±13.5% vs. 68.8±12.9%, perosion and OCT-CN in vivo. OCT-erosion is a frequent finding in patients with ACS, especially in those with NSTE-ACS and younger patients. OCT-CN is the least common etiology for ACS and is more common in older patients. PMID:23810884

  16. Effective anti-thrombotic therapy without stenting: intravascular optical coherence tomography-based management in plaque erosion (the EROSION study).

    Science.gov (United States)

    Jia, Haibo; Dai, Jiannan; Hou, Jingbo; Xing, Lei; Ma, Lijia; Liu, Huimin; Xu, Maoen; Yao, Yuan; Hu, Sining; Yamamoto, Erika; Lee, Hang; Zhang, Shaosong; Yu, Bo; Jang, Ik-Kyung

    2017-03-14

    Plaque erosion, compared with plaque rupture, has distinctly different underlying pathology and therefore may merit tailored therapy. In this study, we aimed to assess whether patients with acute coronary syndrome (ACS) caused by plaque erosion might be stabilized by anti-thrombotic therapy without stent implantation. This was a single-centre, uncontrolled, prospective, proof-of concept study. Patients with ACS including ST-segment elevation myocardial infarction were prospectively enrolled. If needed, aspiration thrombectomy was performed. Patients diagnosed with plaque erosion by optical coherence tomography (OCT) and residual diameter stenosis 50% reduction of thrombus volume at 1 month compared with baseline. The secondary endpoint was a composite of cardiac death, recurrent ischaemia requiring revascularization, stroke, and major bleeding. Among 405 ACS patients with analysable OCT images, plaque erosion was identified in 103 (25.4%) patients. Sixty patients enrolled and 55 patients completed the 1-month follow-up. Forty-seven patients (47/60, 78.3%; 95% confidence interval: 65.8-87.9%) met the primary endpoint, and 22 patients had no visible thrombus at 1 month. Thrombus volume decreased from 3.7 (1.3, 10.9) mm3 to 0.2 (0.0, 2.0) mm3. Minimal flow area increased from 1.7 (1.4, 2.4) mm2 to 2.1 (1.5, 3.8) mm2. One patient died of gastrointestinal bleeding, and another patient required repeat percutaneous coronary intervention. The rest of the patients remained asymptomatic. For patients with ACS caused by plaque erosion, conservative treatment with anti-thrombotic therapy without stenting may be an option.

  17. Harmonic Intravascular Ultrasound

    NARCIS (Netherlands)

    M.E. Frijlink (Martijn)

    2006-01-01

    textabstractMedical ultrasound is a popular imaging modality in cardiology. Harmonic Imaging is a technique that has been shown to increase the image quality of diagnostic ultrasound at frequencies below 10 MHz. However, Intravascular Ultrasound, which is a technique to acoustically investigate arte

  18. Harmonic Intravascular Ultrasound

    NARCIS (Netherlands)

    M.E. Frijlink (Martijn)

    2006-01-01

    textabstractMedical ultrasound is a popular imaging modality in cardiology. Harmonic Imaging is a technique that has been shown to increase the image quality of diagnostic ultrasound at frequencies below 10 MHz. However, Intravascular Ultrasound, which is a technique to acoustically investigate arte

  19. Intravascular lymphoma mimicking vasculitis.

    Science.gov (United States)

    Prayson, Richard A

    2016-12-01

    Intravascular lymphoma is a rare malignancy which is characterized by a proliferation of atypical appearing B cells, generally confined to vascular lumina. A tissue biopsy demonstrating the pathology is required to make a diagnosis. The tumor is often disseminated at the time of diagnosis and prognosis is poor, even with aggressive chemotherapy. Neurologic presentations of this neoplasm can be quite varied. This report documents the presence of intravascular lymphoma diagnosed on a brain biopsy in a 60-year-old man. He initially presented 6months before brain biopsy with chest pain and hypotension, warranting coronary artery bypass graft surgery. Four months later, he presented with signs attributed to a stroke (diaphoresis, slumped over in a chair and left hand weakness). He subsequently developed a sudden onset wide-based gait, left leg numbness, word finding difficulties and worsening confusion. A MRI study showed multiple infarcts in the brain, including cerebellum. Invasive angiogram suggested vasculitis. He was started on a course of treatment for presumed central nervous system vasculitis. He continued to develop signs suggestive of ongoing infarct development and a biopsy from the right parietal was taken. The biopsy showed atypical intravascular CD20 positive staining B cells, consistent with intravascular lymphoma. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Intravascular "mulberry-like" bodies

    DEFF Research Database (Denmark)

    Sørensen, Flemming Brandt; Klebe, J G; Henriques, U V

    1988-01-01

    Intravascular "mulberry-like" bodies in a stillborn female infant with moderate maceration are reported. The histogenesis of these structures is discussed based on light-microscopic, immunohistochemical and ultrastructural findings. No demonstrable causal relation between the intravascular lesions...... and fetal death was found, the cause of death being attributed to intrauterine asphyxia. It is concluded, that intravascular "mulberry-bodies" most likely represent artifacts due to red blood cell autolysis....

  1. Disseminated intravascular coagulation in cancer patients

    NARCIS (Netherlands)

    M. Levi

    2009-01-01

    Disseminated intravascular coagulation (DIC) is a syndrome that may complicate a variety of diseases, including malignant disease. DIC is characterized by widespread, intravascular activation of coagulation (leading to intravascular fibrin deposition) and simultaneous consumption of coagulation fact

  2. How Is Disseminated Intravascular Coagulation Treated?

    Science.gov (United States)

    ... the NHLBI on Twitter. How Is Disseminated Intravascular Coagulation Treated? Treatment for disseminated intravascular coagulation (DIC) depends ... and treat the underlying cause. Acute Disseminated Intravascular Coagulation People who have acute DIC may have severe ...

  3. Obstetrical disseminated intravascular coagulation score.

    Science.gov (United States)

    Kobayashi, Takao

    2014-06-01

    Obstetrical disseminated intravascular coagulation (DIC) is usually a very acute, serious complication of pregnancy. The obstetrical DIC score helps with making a prompt diagnosis and starting treatment early. This DIC score, in which higher scores are given for clinical parameters rather than for laboratory parameters, has three components: (i) the underlying diseases; (ii) the clinical symptoms; and (iii) the laboratory findings (coagulation tests). It is justifiably appropriate to initiate therapy for DIC when the obstetrical DIC score reaches 8 points or more before obtaining the results of coagulation tests. Improvement of blood coagulation tests and clinical symptoms are essential to the efficacy evaluation for treatment after a diagnosis of obstetrical DIC. Therefore, the efficacy evaluation criteria for obstetrical DIC are also defined to enable follow-up of the clinical efficacy of DIC therapy.

  4. An intravascular protein osmometer.

    Science.gov (United States)

    Henson, J W; Brace, R A

    1983-05-01

    Our purpose was to develop an intravascular osmometer for measuring the colloid (i.e., protein) osmotic pressure (COP) of circulating blood. A semipermeable hollow fiber from a Cordis Dow artificial kidney (C-DAK 4000) was attached to polyethylene tubing on one end, filled with saline, and sealed at the other end. This was small enough to be inserted into the vasculature of research animals. Protein osmotic pressure plus hydrostatic pressure was measured by a Statham pressure transducer attached to the hollow fiber. Simultaneously, a second catheter and transducer was used to measure hydrostatic pressure, which was subtracted from the pressure measured from the fiber with an on-line computer. The system was documented by a variety of tests. The colloid osmotic pressure vs. albumin concentration curve determined with the fiber is identical to the curve determined by standard membrane osmometry. The time constant for 2- and 8-cm fibers was 2.6 +/- 0.6 and 1.5 +/- 0.5 (+/- SD) min, respectively. The reflection coefficient (+/- SD) of the fiber for NaCl is 0.042 +/- 0.019 (n = 38); COP measured at varying temperatures (absolute scale) changed linearly as expected from COP = nCRT (i.e., van't Hoff's law). Finally, hollow-fiber osmometers were inserted into femoral veins of dogs and sheep, and blood COP was continuously recorded during osmotic manipulations. In conclusion, we attempted to develop and document a simple method for continuous measurement of intravascular colloid osmotic pressure.

  5. Improving metrology for micro-optics manufacturing

    Science.gov (United States)

    Davies, Angela D.; Bergner, Brent C.; Gardner, Neil W.

    2003-11-01

    Metrology is one of the critical enabling technologies for realizing the full market potential for micro-optical systems. Measurement capabilities are currently far behind present and future needs. Much of today"s test equipment was developed for the micro-electronics industry and is not optimized for micro-optic materials and geometries. Metrology capabilities currently limit the components that can be realized, in many cases. Improved testing will be come increasingly important as the technology moves to integration where it will become important to "test early and test often" to achieve high yields. In this paper, we focus on micro-refractive components in particular, and describe measurement challenges for this class of components and current and future needs. We also describe a new micro-optics metrology research program at UNC Charlotte under the Center for Precision Metrology and the new Center for Optoelectronics and Optical Communications to address these needs.

  6. AD Ejection Line Studies and Optics Improvements

    CERN Document Server

    Belochitskii, P

    2013-01-01

    This paper is a summary of the work we made to understand and improve the AD ejection line optics. In 2011 significant differences were noticed between the optical properties of the AD ejection line and the MAD model. Investigations started to find out the sources of discrepancy. Better understanding of the ejection line optics was obtained and corrections were applied to the model of ejection line. The beam delivery to the experiments is better understood now. The results obtained might be useful as well for the optics design of AD to ELENA transfer line. Potential problems with the fringing field model in MAD were pointed out, when bending magnets with large bending angles and small bending radius are involved.

  7. Improvements for Optics Measurement and Corrections software

    CERN Document Server

    Bach, T

    2013-01-01

    This note presents the improvements for the OMC software during a 14 month technical student internship at CERN. The goal of the work was to improve existing software in terms of maintainability, features and performance. Significant improvements in stability, speed and overall development process were reached. The main software, a Java GUI at the LHC CCC, run for months without noteworthy problems. The overall running time of the software chain used for optics corrections was reduced from nearly half an hour to around two minutes. This was the result of analysing and improving several involved programs and algorithms.

  8. Intravascular large B cell lymphoma

    Directory of Open Access Journals (Sweden)

    Ricardo García-Muñoz

    2014-01-01

    Full Text Available Intravascular large B cell lymphoma (IVBCL is a rare type of extranodal large B cell lymphoma characterized by selective growth of lymphoma cells within the microvasculature. We present an illustrative case of intravascular B cell lymphoma suspected by the presence of a very small monoclonal B cell population identified by immunophenotype and polymerase chain reaction in bone marrow. The diagnosis was confirmed by skin biopsy.

  9. A Novel Model of Atherosclerosis in Rabbits Using Injury to Arterial Walls Induced by Ferric Chloride as Evaluated by Optical Coherence Tomography as well as Intravascular Ultrasound and Histology

    Directory of Open Access Journals (Sweden)

    Jinwei Tian

    2012-01-01

    Full Text Available This study aim was to develop a new model of atherosclerosis by FeCl3-induced injury to right common carotid arteries (CCAs of rabbits. Right CCAs were induced in male New Zealand White rabbits (=15 by combination of a cholesterol-rich diet and FeCl3-induced injury to arterial walls. The right and left CCAs were evaluated by histology and in vivo intravascular ultrasound (IVUS and optical coherence tomography (OCT examinations of 24 hours (=3, 8 weeks (=6, and 12 weeks (=6 after injury. Each right CCA of the rabbits showed extensive white-yellow plaques. At eight and 12 weeks after injury, IVUS, OCT, and histological findings demonstrated that the right CCAs had evident eccentric plaques. Six plaques (50% with evident positive remodeling were observed. Marked progression was clearly observed in the same plaque at 12 weeks after injury when it underwent repeat OCT and IVUS. We demonstrated, for the first time, a novel model of atherosclerosis induced by FeCl3. The model is simple, fast, inexpensive, and reproducible and has a high success rate. The eccentric plaques and remodeling of plaques were common in this model. We successfully carried out IVUS and OCT examinations twice in the same lesion within a relatively long period of time.

  10. Automatic segmentation of coronary morphology using transmittance-based lumen intensity-enhanced intravascular optical coherence tomography images and applying a localized level-set-based active contour method.

    Science.gov (United States)

    Joseph, Shiju; Adnan, Asif; Adlam, David

    2016-10-01

    Lumen segmentation from clinical intravascular optical coherence tomography (IV-OCT) images has clinical relevance as it provides a full three-dimensional perspective of diseased coronary artery sections. Inaccurate segmentation may occur when there are artifacts in the image, resulting from issues such as inadequate blood clearance. This study proposes a transmittance-based lumen intensity enhancement method that ensures only lumen regions are highlighted. A level-set-based active contour method that utilizes the local speckle distribution properties of the image is then employed to drive an image-specific active contour toward the true lumen boundaries. By utilizing local speckle properties, the intensity variation issues within the image are resolved. This combined approach has been successfully applied to challenging clinical IV-OCT datasets that contains multiple lumens, residual blood flow, and its shadowing artifact. A method to identify the guide-wire and interpolate the lost lumen segments has been implemented. This approach is fast and can be performed even when guide-wire boundaries are not easily identified. Lumen enhancement also makes it easy to identify vessel side branches. This automated approach is not only able to extract the arterial lumen, but also the smaller microvascular lumens that are associated with the vasa vasorum and with atherosclerotic plaque.

  11. Fast integrated intravascular photoacoustic/ultrasound catheter

    Science.gov (United States)

    Choi, Changhoon; Cho, Seunghee; Kim, Taehoon; Park, Sungjo; Park, Hyoeun; Kim, Jinmoo; Lee, Seunghoon; Kang, Yeonsu; Jang, Kiyuk; Kim, Chulhong

    2016-03-01

    In cardiology, a vulnerable plaque is considered to be a key subject because it is strongly related to atherosclerosis and acute myocardial infarction. Because conventional intravascular imaging devices exhibit several limitations with regard to vulnerable plaque detection, the need for an effective lipid imaging modality has been continuously suggested. Photoacoustic (PA) imaging is a medical imaging technique with a high level of ultrasound (US) resolution and strong optical contrast. In this study, we successfully developed an integrated intravascular photoacoustic/ultrasound (IV-PAUS) imaging system with a catheter diameter of 1.2 mm for lipid-rich atherosclerosis imaging. An Nd:YAG pulsed laser with an excitation wavelength of 1064 nm was utilized. IV-PAUS offers 5-mm depth penetration and axial and lateral PA imaging resolutions of 94 μm and 203 μm, respectively, as determined by imaging a 6-μm carbon fiber. We initially obtained 3-dimensional (3D) co-registered PA/US images of metal stents. Subsequently, we successfully obtained 3D coregistered PA/US ex vivo images using an iliac artery from a rabbit atherosclerosis model. Accordingly, lipid-rich plaques were sufficiently differentiated from normal tissue in the ex vivo experiment. We validated these findings histologically to confirm the lipid content.

  12. Extremely refractory Kawasaki disease with disseminated intravascular coagulation.

    Science.gov (United States)

    Koh, Young Kwon; Lee, Jae Hee; Park, Yeong Bong

    2017-07-01

    Disseminated intravascular coagulation is a rare complication of Kawasaki disease and appears in Kawasaki disease patients. We report a case of refractory Kawasaki disease complicated with disseminated intravascular coagulation and giant coronary aneurysm. A 5-month-old boy presented with Kawasaki disease with coagulopathy. Although the coagulopathy improved after fresh-frozen plasma and antithrombin-III administration, the fever persisted despite two rounds of intravenous immunoglobulin, along with intravenous methylprednisolone pulse therapy and infliximab administration. Despite all efforts to treatment, the patient had giant coronary aneurysms and died suddenly.

  13. Nonlinear intravascular ultrasound contrast imaging

    NARCIS (Netherlands)

    Goertz, David E.; Frijlink, Martijn E.; de Jong, N.; van der Steen, Antonius F.W.

    2006-01-01

    Nonlinear contrast agent imaging with intravascular ultrasound (IVUS) is investigated using a prototype IVUS system and an experimental small bubble contrast agent. The IVUS system employed a mechanically scanned single element transducer and was operated at a 20 MHz transmit frequency (F20) for

  14. Intravascular ultrasound tissue harmonic imaging in vivo.

    Science.gov (United States)

    Frijlink, Martijn E; Goertz, David E; van Damme, Luc C A; Krams, Rob; van der Steen, Antonius F W

    2006-10-01

    Tissue harmonic imaging (THI) has been shown to increase image quality of medical ultrasound in the frequency range from 2 to 10 MHz and might, therefore, also be used to improve image quality in intravascular ultrasound (IVUS). In this study we constructed a prototype IVUS system that could operate in both fundamental frequency and second harmonic imaging modes. This system uses a conventional, continuously rotating, single-element IVUS catheter and was operated in fundamental 20 MHz, fundamental 40 MHz, and harmonic 40 MHz modes (transmit 20 MHz, receive 40 MHz). Hydrophone beam characterization measurements demonstrated the build-up of a second harmonic signal as a function of increasing pressure. Imaging experiments were conducted in both a tissue-mimicking phantom and in an atherosclerotic animal model in vivo. Acquisitions of fundamental 20 and 40 MHz and second harmonic acquisitions resulted in cross sections of the phantom and a rabbit aorta. The harmonic results of the imaging experiments showed the feasibility of intravascular THI with a conventional IVUS catheter both in a phantom and in vivo. The harmonic acquisitions also showed the potential of THI to reduce image artifacts compared to fundamental imaging.

  15. Performance improvement of CGHs for optical testing

    Science.gov (United States)

    Pruss, Christof; Reichelt, Stephan; Korolkov, Victor P.; Osten, Wolfgang; Tiziani, Hans J.

    2003-05-01

    The expansion of the field of diffractive optics applications is accompanied by toughening performance requirements for CGHs. Optical testing sets especially high requirements, concerning wavefront accuracy and diffraction efficiency. The key point in fabrication technology is the writing system creating the photomask or the profiled pattern. The diffractive optics fabrication facility at ITO (University of Stuttgart) is based on the circular laser writing system CLWS-300. This flexible and high-accurate tool was originally designed for binary diffractive optics fabrication. This paper presents novel enhancements of this system allowing direct laser writing of a wide range of binary and continuous-relief CGHs on photoresist layers, chromium films and LDW-glass. Main topics of the enhancements were the scanning accuracy and exposure control. Many types of CGHs (binary precision holograms for optical testing, Shack-Hartmann arrays, microlens discs for confocal microscopy, diffractive interferometer objectives, doughnut generators etc.) have been manufactured using the developed algorithms and hardware.

  16. Management and Outcome of Patients With Acute Coronary Syndrome Caused by Plaque Rupture Versus Plaque Erosion: An Intravascular Optical Coherence Tomography Study.

    Science.gov (United States)

    Hu, Sining; Zhu, Yinchun; Zhang, Yingying; Dai, Jiannan; Li, Lulu; Dauerman, Harold; Soeda, Tsunenari; Wang, Zhao; Lee, Hang; Wang, Chao; Zhe, Chunyang; Wang, Yan; Zheng, Gonghui; Zhang, Shaosong; Jia, Haibo; Yu, Bo; Jang, Ik-Kyung

    2017-02-24

    Plaque rupture and erosion are the 2 most common mechanisms for acute coronary syndromes. However, the outcome of these 2 distinct pathologies in patients with acute coronary syndromes has never been studied. We retrospectively studied 141 patients with acute coronary syndromes who underwent optical coherence tomography (OCT) imaging of the culprit lesion prior to stenting from the Massachusetts General Hospital OCT Registry. Management (stent versus no stent), poststent OCT findings, and outcomes were compared. Among the 141 culprit lesions, rupture was found in 79 (56%) patients and erosion in 62 (44%). Stent implantation was performed in 77 (97.5%) patients with rupture versus 49 (79.0%) in those with erosion (Perosion group. Plaque rupture was associated with a higher incidence of no reflow or slow flow and distal embolization. Although cardiac event rates were comparable between the two groups at the 1-year follow-up, none of the erosion patients who were treated conservatively without stenting had adverse cardiac events. Unfavorable poststent OCT findings were more frequent in rupture patients compared with erosion patients. A subset of erosion patients who were treated conservatively without stenting remained free of adverse cardiac events for up to 1 year. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  17. Does Dopplersignal enhancement with Levovist improve the diagnostic confidence of duplex scanning of the iliac arteries?--(A pilot study with correlation to intravascular ultrasound)

    DEFF Research Database (Denmark)

    Vogt, K C; Jensen, F; Schroeder, T V

    1998-01-01

    To evaluate whether echo-enhancement with Levovist improves the diagnostic confidence of duplex scanning of the iliac arteries.......To evaluate whether echo-enhancement with Levovist improves the diagnostic confidence of duplex scanning of the iliac arteries....

  18. Improved evaluation of optical depth components from Langley plot data

    Science.gov (United States)

    Biggar, S. F.; Gellman, D. I.; Slater, P. N.

    1990-01-01

    A simple, iterative procedure to determine the optical depth components of the extinction optical depth measured by a solar radiometer is presented. Simulated data show that the iterative procedure improves the determination of the exponent of a Junge law particle size distribution. The determination of the optical depth due to aerosol scattering is improved as compared to a method which uses only two points from the extinction data. The iterative method was used to determine spectral optical depth components for June 11-13, 1988 during the MAC III experiment.

  19. [Disseminated intravascular coagulation: clinical and biological diagnosis].

    Science.gov (United States)

    Touaoussa, Aziz; El Youssi, Hind; El Hassani, Imane; Hanouf, Daham; El Bergui, Imane; Zoulati, Ghizlane; Amrani Hassani, Moncef

    2015-01-01

    Disseminated intravascular coagulation (DIC) is a syndrome characterized by the systemic activation of blood coagulation. Its pathophysiological mechanisms are complex and dependent on the underlying pathology, making the clinical and biological expression of quite variable DIC. Among the various biological parameters disrupted, most are not specific, and none of them allows in itself to make the diagnosis. All this does not facilitate the task of the practitioner for diagnosis of overt DIC, much less that of the non-overt DIC, early stage whose treatment would improve the prognosis. These considerations have led to develop scores, combining several parameters depending on their availability in daily practice, as well as their diagnostic relevance. Of all the scores, the ISTH (International society of thrombosis and hemostasis) remains the most used.

  20. Electromagnetic actuation methods for intravascular locomotive microrobot.

    Science.gov (United States)

    Cha, Kyoungrae; Jeong, Semi; Choi, Jongho; Qin, Lulu; Li, Jie; Park, Jongoh; Park, Sukho

    2010-01-01

    Heart diseases such as angina pectoris and myocardial infarction have been becoming the leading causes of death all over the world in recent years. The pharmacotherapy and the surgical operations have been executed for treating heart problems. The percutaneous coronary intervention (PCI) with catheter is frequently used for the treatment of coronary artery diseases, but the treatment of chronic total occlusion (CTO) is very difficult and challenging operation, since there is no efficient alternative therapy until now. For this reason, the microrobot to improve the intravascular treatment is one of the growing research areas. In this paper, various electromagnetic actuation (EMA) systems to supply driving power for the microrobot were proposed. The performance of the locomotion of microrobot in the 2D and 3D space were validated with in-vitro experiments and also the in-vivo tests were performed for demonstrating the movement of microrobot in the living rabbit.

  1. Ventricular metastasis resulting in disseminated intravascular coagulation

    Directory of Open Access Journals (Sweden)

    Davis Ian D

    2005-05-01

    Full Text Available Abstract Background Disseminated Intravascular Coagulation (DIC complicates up to 7% of malignancies, the commonest solid organ association being adenocarcinoma. Transitional Cell Carcinoma (TCC has rarely been associated with DIC. Case presentation A 74-year-old woman with TCC bladder and DIC was found to have a cardiac lesion suspicious for metastatic disease. The DIC improved with infusion of plasma and administration of Vitamin K, however the cardiac lesion was deemed inoperable and chemotherapy inappropriate; given the patients functional status. We postulate that direct activation of the coagulation cascade by the intraventricular metastasis probably triggered the coagulopathy in this patient. Conclusion Cardiac metastases should be considered in cancer patients with otherwise unexplained DIC. This may influence treatment choices.

  2. Intra-stent tissue evaluation within bare metal and drug-eluting stents > 3 years since implantation in patients with mild to moderate neointimal proliferation using optical coherence tomography and virtual histology intravascular ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Kitabata, Hironori; Loh, Joshua P.; Pendyala, Lakshmana K.; Omar, Alfazir; Ota, Hideaki; Minha, Sa’ar; Magalhaes, Marco A.; Torguson, Rebecca; Chen, Fang; Satler, Lowell F.; Pichard, Augusto D.; Waksman, Ron, E-mail: ron.waksman@medstar.net

    2014-04-15

    Objective: We aimed to compare neointimal tissue characteristics between bare-metal stents (BMS) and drug-eluting stents (DES) at long-term follow-up using optical coherence tomography (OCT) and virtual histology intravascular ultrasound (VH-IVUS). Background: Neoatherosclerosis in neointima has been reported in BMS and in DES. Methods: Thirty patients with 36 stented lesions [BMS (n = 17) or DES (n = 19)] > 3 years after implantation were prospectively enrolled. OCT and VH-IVUS were performed and analyzed independently. Stents with ≥ 70% diameter stenosis were excluded. Results: The median duration from implantation was 126.0 months in the BMS group and 60.0 months in the DES group (p < 0.001). Lipid-laden intima (58.8% vs. 42.1%, p = 0.317), thrombus (17.6% vs. 5.3%, p = 0.326), and calcification (35.3% vs. 26.3%, p = 0.559) did not show significant differences between BMS and DES. When divided into 3 time periods, the cumulative incidence of lipid-laden neointima from > 3 years to < 9 years was similar between BMS and DES (42.9% vs. 42.1%, p = 1.000). Furthermore, it continued to gradually increase over time in both groups. OCT-derived thin-cap fibroatheroma (TCFA) was observed in 17.6% of BMS- and 5.3% of DES-treated lesions (p = 0.326). No stents had evidence of intimal disruption. The percentage volume of necrotic core (16.1% [9.7, 20.3] vs. 9.7% [7.0, 16.5], p = 0.062) and dense calcium (9.5% [3.8, 13.6] vs. 2.7% [0.4, 4.9], p = 0.080) in neointima tended to be greater in BMS-treated lesions. Intra-stent VH-TCFA (BMS vs. DES 45.5% vs. 18.2%, p = 0.361) did not differ significantly. Conclusion: At long-term follow-up beyond 3 years after implantation, the intra-stent neointimal tissue characteristics appeared similar for both BMS and DES.

  3. Optical Theory Improvements to Space Domain Awareness

    Science.gov (United States)

    2016-09-15

    observations are collected through ground-based radar and optical systems as well as space based assets . This research focuses on a ground-based...addition, his professional mentoring will be a great asset going forward in my career. Thanks to Capt Kyle Stewart for helpful discussions on implementation...visualization demonstrates how the point detection, matched filter , Binary Hypothesis Test (BHT), and MHT algorithms are related. . . . . . . . . . . . . 13 2.5

  4. Manufacturing Science of Improved Molded Optics

    Science.gov (United States)

    2013-12-05

    a physical point shear thinning is an unlikely explanation. In a study of friction mechanisms in polymer extrusion , Joshi et al.27 present a...41 Appendix C2 – glass extrusion paper draft 61 Appendix C3 - ring compression test paper draft (Navier law) 97 D. Protective coatings...complex thermo-mechanical behavior of an optical glass during simulation of the lens molding, extrusion and other glass forming processes. This

  5. Improved optical planar waveguides for lasers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Demonstrate efficacy of a novel growth technique for planar waveguides (PWG) Enable PWG laser technology with improved performance, efficiency and manufacturability....

  6. Iatrogenic intravascular pneumocephalus secondary to intravenous catheterization

    Energy Technology Data Exchange (ETDEWEB)

    Yildiz, Altan; Oezer, Caner; Egilmez, Hulusi; Duce, Meltem Nass; Apaydin, Demir F.; Yalcinoglu, Orhan [Department of Radiology, Faculty of Medicine, Mersin University (Turkey)

    2002-03-01

    The presence of pneumocephalus without a history of intracranial or intrathecal procedures is a significant radiographic finding. Although pneumocephalus means a violation of the dural barrier or the presence of infection, intravascular pneumocephalus is different from intraparenchymal pneumocephalus and its benign nature must be known in the presence of intravenous catheterization. Herein, we present a case of iatrogenic intravascular pneumocephalus with CT findings. To our knowledge, there are only a few reported cases of iatrogenic intravascular pneumocephalus in the literature. Careful intravenous catheterization and diagnosis of the condition on imaging helps to prevent unnecessary treatment procedures. (orig.)

  7. Treatment of Disseminated Intravascular Coagulation.

    Science.gov (United States)

    Makruasi, Nisa

    2015-11-01

    Disseminated intravascular coagulation (DIC) is a syndrome characterized by systemic activation of blood coagulation, generation of thrombin, and leading to disturbance of the microvasculature. In this article, definition and diagnostic criteria of DIC depend on the International Society of Thrombosis and Haemostasis (ISTH). There is no gold standard for diagnosis of DIC, only low quality evidence is used in general practice. Many diagnostic tests and repeated measurement are required. For the treatment of DIC, there is no good quality evidence. The most important treatment for DIC is the specific treatment of the conditions associated DIC. Platelets and/or plasma transfusion may be also necessary if indicated. Nevertheless, there is no gold standard for diagnosis and treatment of DIC, we use only low quality evidence in general practice.

  8. Experience with intravascular lead extraction

    Institute of Scientific and Technical Information of China (English)

    MA Jian; TANG Kai; WANG Fang-zheng; ZHANG Shu; HUANG Cong-xin

    2005-01-01

    @@ With the increase of clinical use of cardiac pacemaker, a certain kinds of severe leads-related complications (especially infection) have presented in a few patients who underwent pacemaker implantation. The best way to manage this problem is to remove the transvenous leads.1,2 The technique for percutaneous removal of transvenous leads have undergone considerable development in western countries over the past 2 decades. However, there was scarce data on the application of this technique in China. This article reports the results of transvenous extraction of 171 permanent pacemaker leads with the standard lead extraction devices and intravascular countertraction technique during the period from January 1996 to May 2005 in the Center of Arrhythmia Diagnosis and Treatment, Fu Wai Hospital, Beijing, China.

  9. Intravascular Stenting in Microvascular Anastomoses

    DEFF Research Database (Denmark)

    Assersen, Kristine; Sørensen, Jens

    2015-01-01

    Background The effect of intravascular stenting (IVaS) on microvascular anastomoses has given adverse results. For experienced microsurgeons the benefit of IVaS is doubtful. We have investigated the potential benefit of the IVaS technique for two groups of inexperienced microsurgeons with different...... surgical levels of experience (medical students and young residents). Experienced microsurgeons acted as a control group. Materials and Methods In an experimental crossover study, 139 microsurgical anastomoses were performed on the femoral artery in 70 rats by 10 surgeons. On one side of the rat, the IVaS...... spent on the anastomosis. Results No significant difference in patency rates was seen between the stenting and conventional technique in all three groups. The experienced microsurgeons had 100% patency rate with both techniques. The medical students had 20/28 in the IVaS and 19/28 conventional group...

  10. Intravascular probe for detection of vulnerable plaque

    Science.gov (United States)

    Patt, Bradley E.; Iwanczyk, Jan S.; MacDonald, Lawrence R.; Yamaguchi, Yuko; Tull, Carolyn R.; Janecek, Martin; Hoffman, Edward J.; Strauss, H. William; Tsugita, Ross; Ghazarossian, Vartan

    2001-12-01

    Coronary angiography is unable to define the status of the atheroma, and only measures the luminal dimensions of the blood vessel, without providing information about plaque content. Up to 70% of heart attacks are caused by minimally obstructive vulnerable plaques, which are too small to be detected adequately by angiography. We have developed an intravascular imaging detector to identify vulnerable coronary artery plaques. The detector works by sensing beta or conversion electron radiotracer emissions from plaque-binding radiotracers. The device overcomes the technical constraints of size, sensitivity and conformance to the intravascular environment. The detector at the distal end of the catheter uses six 7mm long by 0.5mm diameter scintillation fibers coupled to 1.5m long plastic fibers. The fibers are offset from each other longitudinally by 6mm and arranged spirally around a guide wire in the catheter. At the proximal end of the catheter the optical fibers are coupled to an interface box with a snap on connector. The interface box contains a position sensitive photomultiplier tube (PSPMT) to decode the individual fibers. The whole detector assembly fits into an 8-French (2.7 mm in diameter) catheter. The PSPMT image is further decoded with software to give a linear image, the total instantaneous count rate and an audio output whose tone corresponds to the count rate. The device was tested with F-18 and Tl-204 sources. Spectrometric response, spatial resolution, sensitivity and beta to background ratio were measured. System resolution is 6 mm and the sensitivity is >500 cps / micrometers Ci when the source is 1 mm from the detector. The beta to background ratio was 11.2 for F-18 measured on a single fiber. The current device will lead to a system allowing imaging of labeled vulnerable plaque in coronary arteries. This type of signature is expected to enable targeted and cost effective therapies to prevent acute coronary artery diseases such as: unstable angina

  11. Performance improvement for optical packet switch with shared buffers

    Institute of Scientific and Technical Information of China (English)

    Junjie Yang; Qingji Zeng; Jie Li; Tong Ye; Guolong Zhu

    2005-01-01

    @@ In this paper, an inner wavelength method is proposed to enlarge buffering capacity of shared fiber delay line buffers. In addition, an optical packet switch called extended shared buffer type optical packet switch(extended SB-OPS) is proposed to realize the inner wavelength method. In order to further improve performance of extended SB-OPS, a greedy algorithm based on inner wavelength method is introduced.The performance of extended SB-OPS is evaluated by simulation experiments.

  12. Improved Fiber-Optic-Coupled Pressure And Vibration Sensors

    Science.gov (United States)

    Zuckerwar, Allan J.; Cuomo, Frank W.

    1994-01-01

    Improved fiber-optic coupler enables use of single optical fiber to carry light to and from sensor head. Eliminates problem of alignment of multiple fibers in sensor head and simplifies calibration by making performance both more predictable and more stable. Sensitivities increased, sizes reduced. Provides increased margin for design of compact sensor heads not required to contain amplifier circuits and withstand high operating temperatures.

  13. Improved optical performance monitoring technique based on nonlinear optics for high-speed WDM Nyquist systems

    Science.gov (United States)

    Guesmi, Latifa; Menif, Mourad

    2016-04-01

    The field of fiber optics nonlinearity is more discussed last years due to such remarkable enhancement in the nonlinear processes efficiency. In this paper, and for optical performance monitoring (OPM), a new achievement of nonlinear effects has been investigated. The use of cross-phase modulation (XPM) and four-wave mixing (FWM) effects between input optical signal and inserted continuous-wave probe has proposed for impairments monitoring. Indeed, transmitting a multi-channels phase modulated signal at high data rate (1 Tbps WDM Nyquist NRZ- DP-QPSK) improves the sensitivity and the dynamic range monitoring. It was observed by simulation results that various optical parameters including optical power, wavelength, chromatic dispersion (CD), polarization mode dispersion (PMD), optical signal-to-noise ratio (OSNR), Q-factor and so on, can be monitored. Also, the effect of increasing the channel spacing between WDM signals is studied and proved its use for FWM power monitoring.

  14. Recanalized chronic coronary thrombus: unraveling a hazy coronary lesion by intravascular ultrasound.

    Science.gov (United States)

    Karamasis, Grigoris V; Chotai, Shayna; Khokhar, Azhar A; Kelly, Paul A

    2016-04-01

    Hazy lesions in coronary angiography can often be a puzzle for the interventional cardiologist. Recanalized chronic coronary thrombus, although rare, is one of the potential diagnoses. Intracoronary imaging with intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are tools that can guide to the correct diagnosis. We present the images of a case where IVUS was used to unravel such a lesion.

  15. Optical fiber sensors measurement system and special fibers improvement

    Science.gov (United States)

    Jelinek, Michal; Hrabina, Jan; Hola, Miroslava; Hucl, Vaclav; Cizek, Martin; Rerucha, Simon; Lazar, Josef; Mikel, Bretislav

    2017-06-01

    We present method for the improvement of the measurement accuracy in the optical frequency spectra measurements based on tunable optical filters. The optical filter was used during the design and realization of the measurement system for the inspection of the fiber Bragg gratings. The system incorporates a reference block for the compensation of environmental influences, an interferometric verification subsystem and a PC - based control software implemented in LabView. The preliminary experimental verification of the measurement principle and the measurement system functionality were carried out on a testing rig with a specially prepared concrete console in the UJV Řež. The presented system is the laboratory version of the special nuclear power plant containment shape deformation measurement system which was installed in the power plant Temelin during last year. On the base of this research we started with preparation other optical fiber sensors to nuclear power plants measurement. These sensors will be based on the microstructured and polarization maintaining optical fibers. We started with development of new methods and techniques of the splicing and shaping optical fibers. We are able to made optical tapers from ultra-short called adiabatic with length around 400 um up to long tapers with length up to 6 millimeters. We developed new techniques of splicing standard Single Mode (SM) and Multimode (MM) optical fibers and splicing of optical fibers with different diameters in the wavelength range from 532 to 1550 nm. Together with development these techniques we prepared other techniques to splicing and shaping special optical fibers like as Polarization-Maintaining (PM) or hollow core Photonic Crystal Fiber (PCF) and theirs cross splicing methods with focus to minimalize backreflection and attenuation. The splicing special optical fibers especially PCF fibers with standard telecommunication and other SM fibers can be done by our developed techniques. Adjustment

  16. Asian-variant intravascular lymphoma in the African race

    Directory of Open Access Journals (Sweden)

    Holly Geyer

    2012-03-01

    Full Text Available Intravascular large B-cell lymphoma (IVLBCL is an exceptionally rare form of non- Hodgkin lymphoma (NHL distinguished by the preferential growth of neoplastic cells within blood vessel lumen. Challenging to detect and deemed disseminated at diagnosis, this condition is characterized by a highly aggressive, inconspicuous course with a high mortality rate. We describe the case of a 48 year-old African-American female presenting with a two month history of low-grade fevers and malaise. Laboratory data was notable for anemia, thrombocytopenia, elevated liver function tests, and hematuria. An extensive workup for infectious, rheumatologic and malignant causes was negative. Her symptoms progressed and within two weeks, she was admitted for disseminated intravascular coagulation (DIC. Her course was complicated by diffuse pulmonary hemorrhage and ultimately, care was withdrawn. Autopsy identified widespread CD-20 positive intravascular large B-cell lymphoma with significant hepatosplenic involvement, characteristic of the Asian variant IVLBCL. This case uniquely highlights development of the Asian variant IVLBVL in a previously undescribed race. Identified by its intraluminal vascular growth pattern, IVLBCL generally spares lymphatic channels. Diagnosis and differentiation of this condition from other hematological malignancies via skin, visceral and bone marrow biopsy is imperative as anthracycline-containing chemotherapies may significantly improve clinical outcomes. This article outlines the common presentation, natural course, and treatment options of IVLBCL, along with the histopathology, immunohistochemistry, and chromosomal aberrations common to this condition.

  17. Intravascular foreign bodies: danger of unretrieved fragmented medical devices.

    Science.gov (United States)

    Tateishi, Minori; Tomizawa, Yasuko

    2009-01-01

    A warning on the danger of unretrieved device fragments and recommendations to mitigate the danger were issued by the Food and Drug Administration in January 2008. The causes of intravascular foreign bodies are classified into three main categories: improper manipulation and usage, device defects, and others, such as patient and anatomical factors. Device failure after long-term use is rarely predicted at the time of approval, since device abnormality is rarely experienced in animal studies and clinical trials conducted during development of the device. Stent fracture due to metal fatigue is one example. Complex complications could occur from simultaneous use of two or more devices with diverse characteristics. The success rate of percutaneous retrieval of intravascular foreign bodies has improved with the advances in commercially available devices. However, the procedure is not always successful and sometimes surgical removal becomes necessary. Appropriate device selection and acquisition of experience in using the device are important. When an intravascular foreign body cannot be retrieved, the risk of complication could be high. Magnetic resonance imaging examination sometimes causes adverse events, including burns due to the heat generated by metal movement. Such information should be correctly recorded. Furthermore, it is necessary to provide patients with adequate information about the characteristics of implanted devices and unretrieved fragments. We reviewed the literature on unretrieved medical device fragments and include articles that describe the Japanese experience.

  18. Improvement of multiprocessing performance by using optical centralized shared bus

    Science.gov (United States)

    Han, Xuliang; Chen, Ray T.

    2004-06-01

    With the ever-increasing need to solve larger and more complex problems, multiprocessing is attracting more and more research efforts. One of the challenges facing the multiprocessor designers is to fulfill in an effective manner the communications among the processes running in parallel on multiple multiprocessors. The conventional electrical backplane bus provides narrow bandwidth as restricted by the physical limitations of electrical interconnects. In the electrical domain, in order to operate at high frequency, the backplane topology has been changed from the simple shared bus to the complicated switched medium. However, the switched medium is an indirect network. It cannot support multicast/broadcast as effectively as the shared bus. Besides the additional latency of going through the intermediate switching nodes, signal routing introduces substantial delay and considerable system complexity. Alternatively, optics has been well known for its interconnect capability. Therefore, it has become imperative to investigate how to improve multiprocessing performance by utilizing optical interconnects. From the implementation standpoint, the existing optical technologies still cannot fulfill the intelligent functions that a switch fabric should provide as effectively as their electronic counterparts. Thus, an innovative optical technology that can provide sufficient bandwidth capacity, while at the same time, retaining the essential merits of the shared bus topology, is highly desirable for the multiprocessing performance improvement. In this paper, the optical centralized shared bus is proposed for use in the multiprocessing systems. This novel optical interconnect architecture not only utilizes the beneficial characteristics of optics, but also retains the desirable properties of the shared bus topology. Meanwhile, from the architecture standpoint, it fits well in the centralized shared-memory multiprocessing scheme. Therefore, a smooth migration with substantial

  19. Stability improvements for the NIST Yb optical lattice clock

    Science.gov (United States)

    Fasano, R. J.; Schioppo, M.; McGrew, W. F.; Brown, R. C.; Hinkley, N.; Yoon, T. H.; Beloy, K.; Oates, C. W.; Ludlow, A. D.

    2016-05-01

    To reach the fundamental limit given by quantum projection noise, optical lattice clocks require advanced laser stabilization techniques. The NIST ytterbium clock has benefited from several generations of extremely high finesse optical cavities, with cavity linewidths below 1 kHz. Characterization of the cavity drift rate has allowed compensation to the mHz/s level, improving the medium-term stability of the cavity. Based on recent measurements using Ramsey spectroscopy with synchronous interrogation, we report a fractional instability σy(1s) thermal noise floor, which will improve our Dick-limited fractional instability at 1 s to below 10-16. Also at University of Colorado.

  20. Shack-Hartmann sensor improvement using optical binning

    CERN Document Server

    Basden, Alastair; Guzman, Dani; Morris, Tim; Myers, Richard; Saunter, Chris

    2007-01-01

    We present a design improvement for a recently proposed type of Shack-Hartmann wavefront sensor that uses a cylindrical (lenticular) lenslet array. The improved sensor design uses optical binning and requires significantly fewer detector pixels than the corresponding conventional or cylindrical Shack-Hartmann sensor, and so detector readout noise causes less signal degradation. Additionally, detector readout time is significantly reduced, which reduces the latency for closed loop systems, and data processing requirements. We provide simple analytical noise considerations and Monte-Carlo simulations, and show that the optically binned Shack-Hartmann sensor can offer better performance than the conventional counterpart in most practical situations, and our design is particularly suited for use with astronomical adaptive optics systems.

  1. Coagulación intravascular diseminada = Disseminated intravascular coagulation

    Directory of Open Access Journals (Sweden)

    Arango Barrientos, Marcos

    2010-12-01

    Full Text Available La coagulación intravascular diseminada (CID es una entidad clínica frecuente que se presenta como fenómeno secundario a diversas enfermedades entre las cuales se destacan las infecciones graves, las neoplasias y las catástrofes obstétricas. Se caracteriza por una activación difusa y simultánea de los sistemas endógenos de la coagulación y la fibrinólisis. El depósito de pequeños trombos en la circulación conduce finalmente a disfunción orgánica múltiple y en algunos casos a la muerte. Las manifestaciones clínicas pueden incluir fenómenos trombóticos y hemorrágicos. Se ha propuesto un puntaje de fácil aplicación para simplificar el diagnóstico de la entidad. El tratamiento incluye el control específico de la causa subyacente que favorece la aparición de la CID, el soporte con hemoderivados en pacientes con manifestaciones de sangrado y la anticoagulación terapéutica en pacientes con trombosis mayores. El desarrollo de CID es un factor pronóstico adverso que aumenta significativamente la tasa de mortalidad. En este artículo de revisión se incluyen los siguientes aspectos de la CID: historia, epidemiología, clasificación, entidades asociadas, fisiopatología, clínica, diagnóstico, tratamiento y pronóstico.

  2. Dosimetry in intravascular brachytherapy; Calculos dosimetricos em braquiterapia intravascular

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Laelia Pumilla Botelho

    2000-03-01

    Among the cardiovascular diseases responsible for deaths in the adult population in almost all countries of the world, the most common is acute myocardial infarction, which generally occurs because of the occlusion of one or more coronary arteries. Several diagnostic techniques and therapies are being tested for the treatment of coronary artery disease. Balloon angioplasty has been a popular treatment which is less invasive than traditional surgeries involving revascularization of the myocardium, thus promising a better quality of life for patients. Unfortunately, the rate of restenosis (re-closing of the vessel) after balloon angioplasty is high (approximately 30-50% within the first year after treatment).Recently, the idea of delivering high radiation doses to coronary arteries to avoid or delay restenosis has been suggested. Known as intravascular brachytherapy, the technique has been used with several radiation sources, and researchers have obtained success in decreasing the rate of restenosis in some patient populations. In order to study the radiation dosimetry in the patient and radiological protection for the attending staff for this therapy, radiation dose distributions for monoenergetic electrons and photons (at nine discrete energies) were calculated for blood vessels of diameter 0.15, o,30 and 0.45 cm with balloon and wire sources using the radiation transport code MCNP4B. Specific calculations were carried out for several candidate radionuclides as well. Two s tent sources (metallic prosthesis that put inside of patient's artery through angioplasty) employing {sup 32} P are also simulated. Advantages and disadvantages of the various radionuclides and source geometries are discussed. The dosimetry developed here will aid in the realization of the benefits obtained in patients for this promising new technology. (author)

  3. Development of catheters for combined intravascular ultrasound and photoacoustic imaging

    Science.gov (United States)

    Karpiouk, Andrei B.; Wang, Bo; Emelianov, Stanislav Y.

    2009-02-01

    Coronary atherosclerosis is a complex disease accompanied by the development of plaques in the arterial wall. Since the vulnerability of the plaques depends on their composition, the appropriate treatment of the arteriosclerosis requires a reliable characterization of the plaques' geometry and content. The intravascular ultrasound (IVUS) imaging is capable of providing structural details of the plaques as well as some functional information. In turn, more functional information about the same plaques can be obtained from intravascular photoacoustic (IVPA) images since the optical properties of the plaque's components differ from that of their environment. The combined IVUS/IVPA imaging is capable of simultaneously detecting and differentiating the plaques, thus determining their vulnerability. The potential of combined IVUS/IVPA imaging has already been demonstrated in phantoms and ex-vivo experiments. However, for in-vivo or clinical imaging, an integrated IVUS/IVPA catheter is required. In this paper, we introduce two prototypes of integrated IVUS/IVPA catheters for in-vivo imaging based on a commercially available single-element IVUS imaging catheter. The light delivery systems are developed using multimode optical fibers with custom-designed distal tips. Both prototypes were tested and compared using an arterial mimicking phantom. The advantages and limitations of both designs are discussed. Overall, the results of our studies suggest that both designs of integrated IVUS/IVPA catheter have a potential for in-vivo IVPA/IVUS imaging of atherosclerotic plaques.

  4. High speed intravascular photoacoustic imaging of atherosclerotic arteries (Conference Presentation)

    Science.gov (United States)

    Piao, Zhonglie; Ma, Teng; Qu, Yueqiao; Li, Jiawen; Yu, Mingyue; He, Youmin; Shung, K. Kirk; Zhou, Qifa; Kim, Chang-Seok; Chen, Zhongping

    2016-02-01

    Cardiovascular disease is the leading cause of death in the industrialized nations. Accurate quantification of both the morphology and composition of lipid-rich vulnerable atherosclerotic plaque are essential for early detection and optimal treatment in clinics. In previous works, intravascular photoacoustic (IVPA) imaging for detection of lipid-rich plaque within coronary artery walls has been demonstrated in ex vivo, but the imaging speed is still limited. In order to increase the imaging speed, a high repetition rate laser is needed. In this work, we present a high speed integrated IVPA/US imaging system with a 500 Hz optical parametric oscillator laser at 1725 nm. A miniature catheter with 1.0 mm outer diameter was designed with a 200 μm multimode fiber and an ultrasound transducer with 45 MHz center frequency. The fiber was polished at 38 degree and enclosed in a glass capillary for total internal reflection. An optical/electrical rotary junction and pull-back mechanism was applied for rotating and linearly scanning the catheter to obtain three-dimensional imaging. Atherosclerotic rabbit abdominal aorta was imaged as two frame/second at 1725 nm. Furthermore, by wide tuning range of the laser wavelength from 1680 nm to 1770 nm, spectroscopic photoacoustic analysis of lipid-mimicking phantom and an human atherosclerotic artery was performed ex vivo. The results demonstrated that the developed IVPA/US imaging system is capable for high speed intravascular imaging for plaque detection.

  5. Micromachined capacitive transducer arrays for intravascular ultrasound

    Science.gov (United States)

    Degertekin, F. Levent; Guldiken, R. Oytun; Karaman, Mustafa

    2005-01-01

    Intravascular ultrasound (IVUS) imaging has become an essential imaging modality for the effective diagnosis and treatment of cardiovascular diseases during the past decade enabled by innovative applications of piezoelectric transducer technology. The limitations in the manufacture and performance of the same piezoelectric transducers have also impeded the improvement of IVUS for emerging clinically important applications such as forward viewing arrays for guiding interventions and high resolution imaging of arterial structure such as vulnerable plaque and fibrous cap, and also implementation of techniques such as harmonic imaging of the tissue and of the contrast agents. Capacitive micromachined ultrasonic transducer (CMUT) technology shows great potential for transforming IVUS not only to satisfy these clinical needs but also to open up possibilities for low-cost imaging devices integrated to therapeutic tools. We have developed manufacturing processes with a maximum process temperature of 250°C to build CMUTs on the same silicon chip with integrated electronics. Using these processes we fabricated CMUT arrays suitable for forward viewing IVUS in the 10-20MHz range. We characterized these array elements in terms of pulse-echo response, radiation pattern measurements and demonstrated its volumetric imaging capabilities on various imaging targets.

  6. Optical Properties of Volcanic Ash: Improving Remote Sensing Observations

    Science.gov (United States)

    Whelley, P.; Colarco, P. R.; Aquila, V.; Krotkov, N. A.; Bleacher, J. E.; Garry, W. B.; Young, K. E.; Lima, A. R.; Martins, J. V.; Carn, S. A.

    2015-12-01

    Many times each year explosive volcanic eruptions loft ash into the atmosphere. Global travel and trade rely on aircraft vulnerable to encounters with airborne ash. Volcanic ash advisory centers (VAACs) rely on dispersion forecasts and satellite data to issue timely warnings. To improve ash forecasts model developers and satellite data providers need realistic information about volcanic ash microphysical and optical properties. In anticipation of future large eruptions we can study smaller events to improve our remote sensing and modeling skills so when the next Pinatubo 1991 or larger eruption occurs, ash can confidently be tracked in a quantitative way. At distances >100km from their sources, drifting ash plumes, often above meteorological clouds, are not easily detected from conventional remote sensing platforms, save deriving their quantitative characteristics, such as mass density. Quantitative interpretation of these observations depends on a priori knowledge of the spectral optical properties of the ash in UV (>0.3μm) and TIR wavelengths (>10μm). Incorrect assumptions about the optical properties result in large errors in inferred column mass loading and size distribution, which misguide operational ash forecasts. Similarly, simulating ash properties in global climate models also requires some knowledge of optical properties to improve aerosol speciation. Recent research has identified a wide range in volcanic ash optical properties among samples collected from the ground after different eruptions. The database of samples investigated remains relatively small, and measurements of optical properties at the relevant particle sizes and spectral channels are far from complete. Generalizing optical properties remains elusive, as does establishing relationships between ash composition and optical properties, which are essential for satellite retrievals. We are building a library of volcanic ash optical and microphysical properties. In this presentation we show

  7. Fold optics path: an improvement for an atomic fountain

    Institute of Scientific and Technical Information of China (English)

    Wei Rong; Zhou Zi-Chao; Shi Chun-Yan; Zhao Jian-Bo; Li Tang; Wang Yu-zhu

    2011-01-01

    A fold optical path is utilized to capture and launch atoms in the atomic fountain.This improved technique reduces the laser power needed by 60 percent,facilitates suppression of the laser power fluctuations,and leads to a more simple and stable system.

  8. Design and study of the intravascular He-Ne laser irradiation therapeutic apparatus

    Science.gov (United States)

    Mao, Haitao; Li, Fangzheng; Wang, Qingguo; Dong, Xingfa; Duan, Qingjie

    1996-09-01

    When the low level He-Ne laser irradiation on both extracorporeally and intracorporeally circulatory blood, it has following useful stimulating functions for the living things: reduce the content of blood plasma middle-molecule substances, increase serum superoxide dismutase, improve hemorheological properties, raise immunity function of organism, etc. We developed the intravascular low level He- Ne irradiation therapeutic apparatus. A He-Ne laser beam of 632.8nm is coupled into 50/125 micrometers optical fiber with the aid of the free lens coupler, after that it entered into the laser pun through the fiber optic connector. The attenuate coefficient of the lens coupler can adjust continuously, so as to choose continuously the output power of the laser pin from 0 to 5 mW. In the pipe of the laser pin there is a large core fiber of 150/190 micrometers, they are stuck to each other. The diameter of the laser pin is less than 0.4 mm, thus it may get into infusion pin of 7, not used with intravenous casing pipe pin. Because it is adopted that the low priced fiber-optic connector, the laser pin can be used only once.

  9. Skin optical clearing for improvement of laser tattoo removal

    Science.gov (United States)

    Genina, Elina A.; Bashkatov, Alexey N.; Gavrilova, Anna A.; Pravdin, Alexander B.; Tuchin, Valery V.; Yaroslavsky, Ilya V.; Altshuler, Gregory B.

    2007-06-01

    The removal of tattoo pigments by laser energy is effected through a process of selective photothermolysis. Dehydration and optical immersion based on refractive index matching of scattering centers with that of surrounding matter through introduction of an exogenous index-matching agent can improve laser tattoo removal by providing increased efficiency of laser delivery to embedded ink particles and enabling the use of shorter wavelength visible lasers more effective on certain inks. Effectiveness of a method of accelerating penetration of the index-matching compounds by enhancing skin permeability through creating a lattice of micro-zones of limited thermal damage in the stratum corneum was studied. As optical clearing agents 100% and 88%-aqueous glycerol solutions were used. The effect of stratum corneum perforation on the rate of the immersion clearing of skin was studied. Dynamics of refractive index alteration of glycerol solution during its interaction with skin samples was monitored. Improvement of tattoo visualization was observed. The results of the experiments have shown that the lattice of island damage method the is effective for transepidermal delivery of optical clearing agents and could be used successfully in in vivo conditions for the enhancement of optical clearing of treated skin area and as enabling improvement of laser tattoo removal.

  10. An unusual case of an ulcerative colitis flare resulting in disseminated intravascular coagulopathy and a bladder hematoma: a case report

    Directory of Open Access Journals (Sweden)

    Christie Dennis

    2004-10-01

    Full Text Available Abstract Background Disorders of coagulation have long been associated with inflammatory bowel disease. Children, as well as adults, with both active and inactive ulcerative colitis have been found to have abnormal coagulation and fibrinolysis. Disseminated intravascular coagulation arises from an overwhelming of the haemostatic regulatory mechanisms leading to an excessive generation of thrombin and a failure of the normal inhibitory pathways to prevent systemic effects of this enzyme. Ulcerative colitis has been associated with disseminated intravascular coagulation in conjunction with septicemia, toxic megacolon and surgery. Case presentation A fourteen-year-old boy with a history of poorly controlled ulcerative colitis presented with nonbilious emesis, hematochezia, and hematuria. Laboratory workup revealed disseminated intravascular coagulation. He was placed on triple antibiotics therapy. An infectious workup came back negative. A computerized tomography (CT scan of the abdomen revealed a marked thickening and irregularity of the bladder wall as well as wall thickening of the rectosigmoid, ascending, transverse, and descending colon. Patient's clinical status remained stable despite a worsening of laboratory values associated with disseminated intravascular coagulation. Patient was begun on high dose intravenous steroids with improvement of the disseminated intravascular coagulation laboratory values within 12 hours and resolution of disseminated intravascular coagulopathy within 4 days. A thorough infectious workup revealed no other causes to his disseminated intravascular coagulation. Conclusions The spectrum of hypercoagulable states associated with ulcerative colitis varies from mild to severe. Although disseminated intravascular coagulation associated with ulcerative colitis is usually related to septicemia, toxic megacolon or surgery, we present a case of an ulcerative colitis flare resulting in disseminated intravascular coagulation

  11. [A method for studying intravascular platelet aggregation in vitro].

    Science.gov (United States)

    Ikonnikova, E I; Chernousova, L A; Moshkina, I R

    1999-06-01

    A simple available method for evaluating intravascular platelet aggregation is proposed. It consists in graphic recording of disaggregation of platelet-rich citrate plasma, which indicates the degree of intravascular aggregation. Intravascular aggregation is notably increased in coronary patients and negligible in normal subjects. The method may be used for the diagnosis of diseases with a high thrombogenic risk.

  12. Improvement of matrix condition of Hybrid, space variant optics by the means of parallel optics design.

    Science.gov (United States)

    Klapp, Iftach; Mendlovic, David

    2009-07-06

    The problem of image restoration of space variant blur is common and important. One of the most useful descriptions of this problem is in its algebraic form I=H*O, where O is the object represented as a column vector, I is the blur image represented as a column vector and H is the PSF matrix that represents the optical system. When inverting the problem to restore the geometric object from the blurred image and the known system matrix, restoration is limited in speed and quality by the system condition. Current optical design methods focus on image quality, therefore if additional image processing is needed the matrix condition is taken "as is". In this paper we would like to present a new optical approach which aims to improve the system condition by proper optical design. In this new method we use Singular Value Decomposition (SVD) to define the weak parts of the matrix condition. We design a second optical system based on those weak SVD parts and then we add the second system parallel to the first one. The original and second systems together work as an improved parallel optics system. Following that, we present a method for designing such a "parallel filter" for systems with a spread SVD pattern. Finally we present a study case in which by using our new method we improve a space variant image system with an initial condition number of 8.76e4, down to a condition number of 2.29e3. We use matrix inversion to simulate image restoration. Results show that the new parallel optics immunity to Additive White Gaussian Noise (AWGN) is much better then that of the original simple lens. Comparing the original and the parallel optics systems, the parallel optics system crosses the MSEIF=0 [db] limit in SNR value which is more than 50db lower then the SNR value in the case of the original simple lens. The new parallel optics system performance is also compared to another method based on the MTF approach.

  13. Nonlinear dynamic characteristics of SMA intravascular stent under radial stochastic loads.

    Science.gov (United States)

    Zhu, Zhiwen; Zhang, Qingxin; Xu, Jia

    2014-01-01

    Nonlinear dynamic characteristics of shape memory alloy (SMA) intravascular stent under radial stochastic loads were studied in this paper. Von de Pol item was improved to interpret the hysteretic phenomena of SMA, and the nonlinear dynamic model of SMA intravascular stent under radial stochastic loads was developed. The conditions of stochastic stability of the system were obtained in singular boundary theory. The steady-state probability density function of the dynamic response of the system was given, and the stochastic Hopf bifurcation characteristics of the system were analyzed. Theoretical analysis and numerical simulation show that the stability of the trivial solution varies with bifurcation parameters, and stochastic Hopf bifurcation appears in the process, which can cause stent fracture or loss. The results of this paper are helpful to application of SMA intravascular stent in biomedical engineering fields.

  14. Introduction of a programme for intravascular transfusions at severe rhesus isoimmunization.

    Science.gov (United States)

    Westgren, M; Jabbar, F; Larsen, J F; Rahman, F; Selbing, A; Stangenberg, M

    1988-01-01

    Thirty-seven fetuses with severe rhesus isoimmunization with a gestational age of less than 30 week underwent 92 intravascular transfusions. Of these, 77 were intracardiac, 13 umbilical vein and two umbilical artery transfusions. Procedure related complications occurred at eight (10%) intracardiac and at two (14%) umbilical cord transfusions. Reversal of hydrops was observed in 10 of 16 fetuses. The perinatal mortality among transfusion treated fetuses was 8/37 (21%). It is concluded that intravascular, intrauterine transfusion leads to improved results among fetuses with early onset of hydrops. Problems concerning indications and technique are discussed.

  15. Image and Signal Processing in Intravascular Ultrasound

    NARCIS (Netherlands)

    W. Li (Wenguang)

    1997-01-01

    textabstractIntravascular ultrasound (rvUS) is a new imaging mOdality providing real-time, crosssectional, high-resolution images of the arterial lumen and vessel wall. In contrast to conventional x-ray angiography that only displays silhouette views of the vessel lumen, IVUS imaging permits visuali

  16. Transducer for harmonic intravascular ultrasound imaging

    NARCIS (Netherlands)

    Vos, Hendrik J.; Frijlink, Martijn E.; Droog, E.J.; Goertz, David E.; Blacquiere, Gerrit; Gisolf, Anton; de Jong, N.; van der Steen, Antonius F.W.

    2005-01-01

    A recent study has shown the feasibility of tissue harmonic imaging (THI) using an intravascular ultrasound (IVUS) transducer. This correspondence describes the design, fabrication, and characterization of a THI-optimized piezoelectric transducer with oval aperture of 0.75 mm by 1 mm. The transducer

  17. Improved magneto-optical trapping of a diatomic molecule

    Science.gov (United States)

    Norrgard, Eric; McCarron, Daniel; Steinecker, Matthew; Demille, David

    2015-05-01

    The magneto-optical trap (MOT) is the workhorse technique for atomic physics in the ultracold regime, serving as the starting point in applications from optical clocks to quantum-degenerate gases. Recently, our group demonstrated the first magneto-optical trap for a molecule, strontium monofluoride (SrF). Here, we present experimental results of two variant trapping schemes which improve upon the original work. In the first, recent insights into the origin of the restoring force in Type-II MOTs (rarely used for atoms but requisite for SrF and other candidate molecules) led to a simple change in polarization scheme for the MOT lasers. In the second, states dark to the restoring MOT beams are diabatically transferred to bright states by synchronously reversing the magnetic field gradient and the laser polarization at RF frequencies. Although magneto-optical trapping of diatomic molecules is in its infancy, our results indicate that access to the ultracold regime may be possible for several molecular species, with potential applications from quantum simulation to tests of fundamental symmetries to ultracold chemistry. We acknowledge funding from ARO and ARO (MURI). E.B.N. acknowledges funding from the NSF GRFP.

  18. Improving resolution of optical coherence tomography for imaging of microstructures

    Science.gov (United States)

    Shen, Kai; Lu, Hui; Wang, James H.; Wang, Michael R.

    2015-03-01

    Multi-frame superresolution technique has been used to improve the lateral resolution of spectral domain optical coherence tomography (SD-OCT) for imaging of 3D microstructures. By adjusting the voltages applied to ? and ? galvanometer scanners in the measurement arm, small lateral imaging positional shifts have been introduced among different C-scans. Utilizing the extracted ?-? plane en face image frames from these specially offset C-scan image sets at the same axial position, we have reconstructed the lateral high resolution image by the efficient multi-frame superresolution technique. To further improve the image quality, we applied the latest K-SVD and bilateral total variation denoising algorithms to the raw SD-OCT lateral images before and along with the superresolution processing, respectively. The performance of the SD-OCT of improved lateral resolution is demonstrated by 3D imaging a microstructure fabricated by photolithography and a double-layer microfluidic device.

  19. Improvements in the optics measurement resolution for the LHC

    CERN Document Server

    Langner, A

    2014-01-01

    Optics measurement algorithms which are based on the measurement of beam position monitor (BPM) turn-by-turn data are currently being improved in preparation for the commissioning of the LHC at higher energy. The turn-by-turn data of one BPM may be used more than once, but the implied correlations were not considered in the final error bar. In this paper the error propagation including correlations is studied for the statistical part of the uncertainty. The confidence level of the measurement is investigated analytically and with simulations.

  20. Improved magneto-optical trapping of a diatomic molecule

    CERN Document Server

    McCarron, D J; Steinecker, M H; DeMille, D

    2014-01-01

    We present experimental results from a new scheme for magneto-optically trapping strontium monofluoride (SrF) molecules, which provides increased confinement compared to our original work. The improved trap employs a new approach to magneto-optical trapping presented by M. Tarbutt, \\emph{arXiv preprint} 1409.0244, which provided insight for the first time into the source of the restoring force in magneto-optical traps (MOTs) where the cycling transition includes dark Zeeman sublevels (known as type-II MOTs). We measure a radial spring constant $20\\times$ greater than in our original work with SrF, comparable to the spring constants reported in atomic type-II MOTs. We achieve a trap lifetime $\\tau_{\\rm{MOT}}=136(2)$~ms, over $2\\times$ longer than originally reported for SrF. Finally, we demonstrate further cooling of the trapped molecules by briefly increasing the trapping lasers' detunings. Our trapping scheme remains a straightforward extension of atomic techniques and marks a step towards the direct product...

  1. Integrated optics to improve resolution on multiple configuration

    Science.gov (United States)

    Liu, Hua; Ding, Quanxin; Guo, Chunjie; Zhou, Liwei

    2015-04-01

    Inspired to in order to reveal the structure to improve imaging resolution, further technical requirement is proposed in some areas of the function and influence on the development of multiple configuration. To breakthrough diffraction limit, smart structures are recommended as the most efficient and economical method, while by used to improve the system performance, especially on signal to noise ratio and resolution. Integrated optics were considered in the selection, with which typical multiple configuration, by use the method of simulation experiment. Methodology can change traditional design concept and to develop the application space. Our calculations using multiple matrix transfer method, also the correlative algorithm and full calculations, show the expected beam shaping through system and, in particular, the experimental results will support our argument, which will be reported in the presentation.

  2. Improved antireflection coated microspheres for biological applications of optical tweezers

    Science.gov (United States)

    Ferro, Valentina; Sonnberger, Aaron; Abdosamadi, Mohammad K.; McDonald, Craig; Schäffer, Erik; McGloin, David

    2016-09-01

    The success of optical tweezers in cellular biology1 is in part due to the wide range of forces that can be applied, from femto- to hundreds of pico-Newtons; nevertheless extending the range of applicable forces to the nanoNewton regime opens access to a new set of phenomena that currently lie beyond optical manipulation. A successful approach to overcome the conventional limits on trapping forces involves the optimization of the trapped probes. Jannasch et al.2 demonstrated that an anti-reflective shell of nanoporous titanium dioxide (aTiO2, nshell = 1.75) on a core particle made out of titanium dioxide in the anatase phase (cTiO2, ncore = 2.3) results in trappable microspheres capable to reach forces above 1 nN. Here we present how the technique can be further improved by coating the high refractive index microspheres with an additional anti-reflective shell made out of silica (SiO2). This external shell not only improves the trap stability for microspheres of different sizes, but also enables the use of functionalization techniques already established for commercial silica beads in biological experiments. We are also investigating the use of these new microspheres as probes to measure adhesion forces between intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 1 (LFA-1) in effector T-Cells and will present preliminary results comparing standard and high-index beads.

  3. Techniques for Intravascular Foreign Body Retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Woodhouse, Joe B.; Uberoi, Raman, E-mail: raman.uberoi@orh.nhs.uk [Oxford University Hospitals (United Kingdom)

    2013-08-01

    As endovascular therapies increase in frequency, the incidence of lost or embolized foreign bodies is increasing. The presence of an intravascular foreign body (IFB) is well recognized to have the potential to cause serious complications. IFB can embolize and impact critical sites such as the heart, with subsequent significant morbidity or mortality. Intravascular foreign bodies most commonly result from embolized central line fragments, but they can originate from many sources, both iatrogenic and noniatrogenic. The percutaneous approach in removing an IFB is widely perceived as the best way to retrieve endovascular foreign bodies. This minimally invasive approach has a high success rate with a low associated morbidity, and it avoids the complications related to open surgical approaches. We examined the characteristics, causes, and incidence of endovascular embolizations and reviewed the various described techniques that have been used to facilitate subsequent explantation of such materials.

  4. [Disseminated intravascular coagulation in solid tumours].

    Science.gov (United States)

    Ferrand, François Régis; Garcia-Hejl, Carine; Moussaid, Yassine; Schernberg, Antoine; Bidard, François-Clément; Pavic, Michel; Khenifer, Safia; Stoclin, Annabelle

    2014-06-01

    Disseminated intravascular coagulation (DIC) is a complex abnormality of hemostasis with dramatic consequences and long described as associated with tumors. Yet the diagnosis and management of paraneoplastic DIC are poorly defined. The purpose of this paper is to review DIC associated with solid tumors, at the pathophysiological and therapeutic levels in particular. We also report data from a recent retrospective series of patients with DIC in the context of a solid tumor, to illustrate the epidemiological, clinical and prognostic.

  5. Temporary intravascular shunts for peripheral vascular trauma.

    Directory of Open Access Journals (Sweden)

    Husain A

    1992-04-01

    Full Text Available Polyvinylchloride (PVC disposable endotracheal suction catheters were successfully used as temporary intravascular shunts in 5 patients of popliteal artery trauma. These simple shunts should be used routinely in such conditions to immediately re-establish blood supply to the ischaemic limb particularly in patients of polytrauma where systemic anticoagulation is contraindicated. This avoids the inherent delay prior to vascular repair and reduces the incidence of irreversible ischemia.

  6. Diagnosis and treatment of disseminated intravascular coagulation.

    Science.gov (United States)

    Levi, M

    2014-06-01

    Disseminated intravascular coagulation (DIC) is a condition in which systemic activation of coagulation without a specific localization occurs, resulting in extensive formation of intravascular fibrin, particularly in small and midsize vessels. Disseminated intravascular coagulation may lead to several altered coagulation parameters, including a low platelet count, abnormal global clotting assays, low levels of physiological anticoagulant proteases, or increased fibrin degradation products. Also, more complex assays for activation of coagulation factors or pathways may indicate involvement of these molecules in DIC. None of these tests alone, however, can accurately ascertain or rebuff a diagnosis of DIC. Nonetheless, a combination of readily available routine assays may be instrumental in establishing a diagnosis of DIC and can also be useful to point to a subset of patients with DIC that may need definite, often costly, interventions in the hemostatic system. Current insights on relevant etiological pathways that may contribute to the occurrence of DIC have led to innovative therapeutic and adjunctive approaches to patient with DIC. Management options directed at the amelioration of hemostatic activation may tentatively be indicated and were found to be advantageous in experimental and clinical investigations. These treatments encompass elimination of tissue factor-mediated thrombin generation or restitution of normal anticoagulant function.

  7. Method to improve the performance of reflectance diffuse optical imaging based on polygonal optical fibers arrangement

    Institute of Scientific and Technical Information of China (English)

    Weitao Li; Zhiyu Qian; Ting Li

    2009-01-01

    In order to improve the performance of reflectance diffuse optical imaging(rDOI),a novel polynomial geometry(PG)of optical fibers arrangement is proposed.Polynomial geometry is based on the hexagonal geometry(HG)and multicentered double-density(MD)mode.The overlapping sensitivity matrix,area ratio(AR),reconstruction image,two-absorber model,arid contrast-to-noise ratio(CNR)in different depths are used to evaluate the performance of PG.The other three geometries including HG,rectangular geometry(RG),and MD mode are also compared with PG.The deformation of the reconstruction images is evaluted by circular ratio(CR).The results prove that the proposed PG has high performance and minimum deformation in quality of reconstruction image in rDOI.

  8. Improved rate control for electron-beam evaporation and evaluation of optical performance improvements.

    Science.gov (United States)

    Gevelber, Michael; Xu, Bing; Smith, Douglas

    2006-03-01

    A new deposition-rate-control and electron-beam-gun (e-gun) strategy was developed that significantly reduces the growth-rate variations for e-beam-deposited SiO2 coatings. The resulting improvements in optical performance are evaluated for multilayer bandpass filters. The adverse effect of uneven silica-source depletion on coating spectral performances during long deposition runs is discussed.

  9. Adaptive Estimation of Intravascular Shear Rate Based on Parameter Optimization

    Science.gov (United States)

    Nitta, Naotaka; Takeda, Naoto

    2008-05-01

    The relationships between the intravascular wall shear stress, controlled by flow dynamics, and the progress of arteriosclerosis plaque have been clarified by various studies. Since the shear stress is determined by the viscosity coefficient and shear rate, both factors must be estimated accurately. In this paper, an adaptive method for improving the accuracy of quantitative shear rate estimation was investigated. First, the parameter dependence of the estimated shear rate was investigated in terms of the differential window width and the number of averaged velocity profiles based on simulation and experimental data, and then the shear rate calculation was optimized. The optimized result revealed that the proposed adaptive method of shear rate estimation was effective for improving the accuracy of shear rate calculation.

  10. Ocean color algorithms in optically shallow waters: limitations and improvements

    Science.gov (United States)

    Carder, Kendall L.; Cannizzaro, Jennifer P.; Lee, Zhongping

    2005-08-01

    Current ocean color algorithms based on remote-sensing reflectance spectra, Rrs(λ), overestimate chlorophyll a concentrations, Chl, and particulate backscattering coefficients, bbp(λ), in optically shallow oceanic waters due to increased bottom reflectance. Since such regions often contain important ecological resources and are heavily influenced by human populations, accurate estimates of Chl and bbp(λ) are essential for monitoring algal blooms (e.g. red tides), detecting sediment resuspension events and quantifying primary productivity. In this study, a large synthetic data set of 500 Rrs(λ) spectra is developed to examine limitations of ocean color algorithms for optically shallow waters and to develop alternative algorithms that can be applied to satellite (e.g. SeaWiFS and MODIS) and aircraft ocean color sensor data. Rrs(λ) spectra are simulated using a semi-analytic model for optically shallow waters. The model is parameterized with sand bottom albedo spectra, ρ(λ), using a wide range of chlorophyll a concentrations (0.03-30 mg m-3), bottom depths (2-50m) and bottom albedos (ρ(550)=0.01-0.30) to provide a robust data set that accurately represents and complements shipboard Rrs(λ) data from the Gulf of Mexico and Bahamian waters. The accuracy of a remotely-based technique developed recently from shipboard Rrs(λ) data is tested on the synthetic data for identifying waters with bottom reflectance contributions at Rrs(555) greater than 25%. Limitations and improvements regarding this method are discussed.

  11. Improving the privacy of optical steganography with temporal phase masks.

    Science.gov (United States)

    Wang, Z; Fok, M P; Xu, L; Chang, J; Prucnal, P R

    2010-03-15

    Temporal phase modulation of spread stealth signals is proposed and demonstrated to improve optical steganography transmission privacy. After phase modulation, the temporally spread stealth signal has a more complex spectral-phase-temporal relationship, such that the original temporal profile cannot be restored when only dispersion compensation is applied to the temporally spread stealth signals. Therefore, it increases the difficulty for the eavesdropper to detect and intercept the stealth channel that is hidden under a public transmission, even with a correct dispersion compensation device. The experimental results demonstrate the feasibility of this approach and display insignificant degradation in transmission performance, compared to the conventional stealth transmission without temporal phase modulation. The proposed system can also work without a clock transmission for signal synchronization. Our analysis and simulation results show that it is difficult for the adversary to detect the existence of the stealth transmission, or find the correct phase mask to recover the stealth signals.

  12. An improved transfer-matrix model for optical superlenses.

    Science.gov (United States)

    Moore, Ciaran P; Blaikie, Richard J; Arnold, Matthew D

    2009-08-01

    The use of transfer-matrix analyses for characterizing planar optical superlensing systems is studied here, and the simple model of the planar superlens as an isolated imaging element is shown to be defective in certain situations. These defects arise due to neglected interactions between the superlens and the spatially varying shadow masks that are normally used as scattering objects for imaging, and which are held in near-field proximity to the superlenses. An extended model is proposed that improves the accuracy of the transfer-matrix analysis, without adding significant complexity, by approximating the reflections from the shadow mask by those from a uniform metal layer. Results obtained using both forms of the transfer matrix model are compared to finite element models and two example superlenses, one with a silver monolayer and the other with three silver sublayers, are characterized. The modified transfer matrix model gives much better agreement in both cases.

  13. Cleaning procedure for improved photothermal background of toroidal optical microresonators

    Science.gov (United States)

    Horak, Erik H.; Knapper, Kassandra A.; Heylman, Kevin D.; Goldsmith, Randall H.

    2016-09-01

    High Q-factors and small mode volumes have made toroidal optical microresonators exquisite sensors to small shifts in the effective refractive index of the WGM modes. Eliminating contaminants and improving quality factors is key for many different sensing techniques, and is particularly important for photothermal imaging as contaminants add photothermal background obscuring objects of interest. Several different cleaning procedures including wet- and dry-chemical procedures are tested for their effect on Q-factors and photothermal background. RCA cleaning was shown to be successful in contrast to previously described acid cleaning procedures, most likely due to the different surface reactivity of the acid reagents used. UV-ozone cleaning was shown to be vastly superior to O2 plasma cleaning procedures, significantly reducing the photothermal background of the resonator.

  14. Optical resolution improvement by nanoparticle's amplitude and phase pattern

    Science.gov (United States)

    Hong, Xin; Sun, Xiaoyaun

    2016-11-01

    Optical detection of nanoparticle with ultra-high sensitivity plays an important role in bio- / nano- and their relative research fields. In our recently developed method, each single particle exhibits unique 4-lobes pattern both in the amplitude and phase images respectively, based on which we explored the possibility of resolution improvement by a particle pair. In this paper two polystyrene beads at the diameter of 100nm were employed with the gap distance ranging from 100-400nm. The amplitude and phase images of the particle pair were simulated by FDTD solver. The images are sensitive to geometrical parameters of the two particles, such as gap distance and direction. The simulation results lead to a resolution of 100nm.

  15. Improved fiber nonlinearity mitigation in dispersion managed optical OFDM links

    Science.gov (United States)

    Tamilarasan, Ilavarasan; Saminathan, Brindha; Murugappan, Meenakshi

    2017-02-01

    Fiber nonlinearity is seen as a capacity limiting factor in OFDM based dispersion managed links since the Four Wave Mixing effects become enhanced due to the high PAPR. In this paper, the authors have compared the linear and nonlinear PAPR reduction techniques for fiber nonlinearity mitigation in OFDM based dispersion managed links. In the existing optical systems, linear transform techniques such as SLM and PTS have been implemented to reduce nonlinear effects. In the proposed study, superior performance of the L2-by-3 nonlinear transform technique is demonstrated for PAPR reduction to mitigate fiber nonlinearities. The performance evaluation is carried out by interfacing multiple simulators. The results of both linear and nonlinear transform techniques have been compared and the results show that nonlinear transform technique outperforms the linear transform in terms of nonlinearity mitigation and improved BER performance.

  16. Intracellular dielectric tagging for improved optical manipulation of mammalian cells

    CSIR Research Space (South Africa)

    Mthunzi, P

    2010-05-01

    Full Text Available Optical micromanipulation of transparent microparticles such as cellularmaterials relies upon the application of optical forces that are crucially dependent on the refractive index contrast between the particle and the surrounding medium. We briefly...

  17. Dichromated-gelatin hologram process for improved optical quality

    Science.gov (United States)

    Stewart, W. C.

    1975-01-01

    Optical distortions are eliminated by use of wetting agency followed by sequential immersion in several alcohol-water baths of increasing alcohol concentration. Dehydration proceeds uniformly over surface of gelatin. Dried plate is free of optically-distorting thickness variations.

  18. Optical fiber strain sensor with improved linearity range

    Science.gov (United States)

    Egalon, Claudio Oliveira (Inventor); Rogowski, Robert S. (Inventor)

    1995-01-01

    A strain sensor is constructed from a two mode optical fiber. When the optical fiber is surface mounted in a straight line and the object to which the optical fiber is mounted is subjected to strain within a predetermined range, the light intensity of any point at the output of the optical fiber will have a linear relationship to strain, provided the intermodal phase difference is less than 0.17 radians.

  19. New metrology techniques improve the production of silicon diffractive optics

    Science.gov (United States)

    Brooks, Cynthia B.; Gully-Santiago, Michael; Grigas, Michelle; Jaffe, Daniel T.

    2014-07-01

    Silicon immersion gratings and grisms offer significant advantages in compactness and performance over frontsurface gratings and over grisms made from lower-index materials. At the same time, the high refractive index of Si (3.4) leads to very stringent constraints on the allowable groove position errors, typically rms error of errors and their origins, we could then implement process controls for each step. The plasma uniformity was improved for the silicon nitride mask etch process and the phase contribution of the plasma etch step was measured. We then used grayscale lithography, a technique in which the photoresist is deliberately underexposed, to measure large-scale nonuniformities in the UV exposure system to an accuracy of 3-5%, allowing us to make corrections to the optical alignment. Additionally, we used a new multiple-exposure technique combined with laser interferometry to measure the relationship between UV exposure dose and line edge shift. From these data we predict the contribution of the etching and photolithographic steps to phase error of the grating surface. These measurements indicate that the errors introduced during the exposure step dominate the contributions of all the other processing steps. This paper presents the techniques used to quantify individual process contributions to phase errors and steps that were taken to improve overall phase uniformity.

  20. Hypothesis: Disseminated Intravascular Inflammation as the Inflammatory Counterpart to Disseminated Intravascular Coagulation

    Science.gov (United States)

    Bull, Brian S.; Bull, Maureen H.

    1994-08-01

    We have identified a leukocyte activation syndrome that is occasionally associated with the transfusion of intraoperatively recovered erythrocytes. This syndrome appears to result from intravascular damage caused by leukocytes activated during the erythrocyte salvage process. We hypothesize that this syndrome is part of a larger disease grouping: disseminated intravascular inflammation (DII). DII is the analog of the coagulation disorder disseminated intravascular coagulation. In disseminated intravascular coagulation, the organ damage results from uncontrolled activation of the clotting pathway; in DII the damage is caused by leukocytes that have become activated by direct contact with bacteria or in rare instances-such as erythrocyte salvage-in the absence of bacteria and bacterial products. Recent studies of the hazards associated with intraoperative blood salvage indicate that activation of leukocytes can be achieved by exposure to activated platelets alone. If such activated leukocytes are reinfused along with the washed erythrocytes, widespread organ damage may result. The lung is the organ most severely affected by activated leukocytes. Adult respiratory distress syndrome is one outcome. It is likely that DII is a presently unrecognized pathophysiological process that complicates a variety of primary disease states and increases their lethality.

  1. High-speed intravascular spectroscopic photoacoustic imaging at 1000 A-lines per second with a 0.9-mm diameter catheter

    Science.gov (United States)

    Li, Yan; Gong, Xiaojing; Liu, Chengbo; Lin, Riqiang; Hau, William; Bai, Xiaosong; Song, Liang

    2015-06-01

    Intravascular spectroscopic photoacoustic technology can image atherosclerotic plaque composition with high sensitivity and specificity, which is critical for identifying vulnerable plaques. Here, we designed and engineered a catheter of 0.9 mm in diameter for intravascular photoacoustic (IVPA) imaging, smaller than the critical size of 1 mm required for clinical translation. Further, a quasifocusing photoacoustic excitation scheme was developed for the catheter, producing well-detectable IVPA signals from stents and lipids with a laser energy as low as ˜30 μJ/pulse. As a result, this design enabled the use of a low-energy, high-repetition rate, ns-pulsed optical parametric oscillator laser for high-speed spectroscopic IVPA imaging at both the 1.2-μm and 1.7-μm spectral bands for lipid detection. Specifically, for each wavelength, a 1-kHz IVPA A-line rate was achieved, ˜100-fold faster than previously reported IVPA systems offering a similar wavelength tuning range. Using the system, spectroscopic IVPA imaging of peri-adventitial adipose tissue from a porcine aorta segment was demonstrated. The significantly improved imaging speed, together with the reduced catheter size and multiwavelength spectroscopic imaging ability, suggests that the developed high-speed IVPA technology is of great potential to be further translated for in vivo applications.

  2. The Diagnosis and Man Disseminated Intravascular Coagulation

    Institute of Scientific and Technical Information of China (English)

    Flelcher B.; Taylor.Jr

    2003-01-01

    @@ This review describes disseminated intravascular coagulation(DIC) as a syndrome in which hemostatic factors are activated and products are generated. This syndrome ranges in severity from an obvious decompensated coagulopathy (overt-DIC) to the subclinical compensated activation of hemostatic factors(non-overt DIC). Ths first part of this review emphasizes two points: First, activation of the hemostatic system is controlled by a vast network of capillaries and venules through anticoagulant and antiinflammatory regulatory factors that operate from the endothelium( e. G. , protein C and thrombomodulin, tissue factor pathway inhibitor).

  3. Optical frequency tripling with improved suppression and sideband selection.

    Science.gov (United States)

    Thakur, Manoj P; Medeiros, Maria C R; Laurêncio, Paula; Mitchell, John E

    2011-12-12

    A novel optical dispersion tolerant millimetre-wave radio-over-fibre system using optical frequency tripling technique with enhanced and selectable sideband suppression is demonstrated. The implementation utilises cascaded optical modulators to achieve either an optical single sideband (OSSB) or double sideband-suppressed carrier (DSB-SC) signal with high sideband suppression. Our analysis and simulation results indicate that the achievable suppression ratio of this configuration is only limited by other system factors such as optical noise and drifting of the operational conditions. The OSSB transmission system performance is assessed experimentally by the transport of 4 WiMax channels modulating a 10 GHz optical upconverted RF carrier as well as for optical frequency doubling and tripling. The 10 GHz and tripled carrier at 30 GHz are dispersion tolerant resulting both in an average relative constellation error (RCE) of -28.7 dB after 40 km of fibre.

  4. Mapping Intravascular Ultrasound Controversies in Interventional Cardiology Practice

    NARCIS (Netherlands)

    Maresca, D.; Adams, S.; Maresca, B.; Van der Steen, A.F.W.

    2014-01-01

    Intravascular ultrasound is a catheter-based imaging modality that was developed to investigate the condition of coronary arteries and assess the vulnerability of coronary atherosclerotic plaques in particular. Since its introduction in the clinic 20 years ago, use of intravascular ultrasound innova

  5. Improved "optical highlighter" probes derived from discosoma red fluorescent protein.

    Science.gov (United States)

    Robinson, Lisbeth C; Marchant, Jonathan S

    2005-02-01

    The tetrameric red fluorescent protein, DsRed, undergoes a rapid red to green color change evoked by short wavelength (lambda highlighter" probe for tracking live cells, organelles, and fusion proteins. This color change results from selective bleaching of the "mature" red-emitting species of DsRed and an enhancement of emission from the "immature" green species, likely caused by dequenching of fluorescence resonance energy transfer occurring within the protein tetramer. Here, we have examined the role of residues known to influence the rate and completeness of chromophore maturation on the cellular and biophysical properties of DsRed mutants. Surprisingly, a single amino acid mutation (N42Q) with increased basal green emission yet rapid chromophore maturation displayed a multiphoton-evoked color change that was brighter, more consistent, more vivid, and easier to evoke than DsRed, despite the larger proportion of green chromophores. Rapidly maturing mutants with more complete chromophore maturation, exhibited little color change and increased resistance to multiphoton bleaching. We describe improved optical and cell biological properties for two DsRed-derived variants which we showcase in photolabeling studies, and discuss these data in terms of implications for fluorescence resonance energy transfer-based probes.

  6. Data center performance improvement using optical wireless links

    Science.gov (United States)

    Arnon, Shlomi

    2017-01-01

    Data centers collect and process information with a capacity that has been increasing from year to year at an almost exponential pace, while many datacenter applications are provided at no cost. This faces datacenter operators with the challenges of meeting exponentially increasing demands for network bandwidth without unreasonable increases in operation and infrastructure cost. In order to meet the requirements of moderate increase in operation and infrastructure cost new technologies are desired. Optical wireless technology could a) reduce the power consumption, b) increase the flexibility and scalability and c) reduce the network overload.. The OWC link could be deployed on top of the existing cable/fiber network layer, such that live migration could be done easily and dynamically and network topology is flexible and adapts quickly to changes in traffic, heat distribution, power consumption and characteristics of the applications. In addition, OWC could provide an easy way to maintains and scale up data centers which would reduce total cost of ownership and increase the return on investment. In this talk we will review the main OWC technologies, algorithms concepts and configurations which improve the performance of next generation data centers.

  7. Pulsed liquid microjet for intravascular injection

    Science.gov (United States)

    Palanker, Daniel V.; Fletcher, Daniel A.; Miller, Jason; Huie, Philip; Marmor, Michael; Blumenkranz, Mark S.

    2002-06-01

    Occlusions of the retinal veins and arteries are associated with common diseases such as hypertension and arteriosclerosis and usually cause severe and irreversible loss of vision. Treatments for these vascular diseases have been unsatisfactory to date in part because of the difficulty of delivering thrombolytic drugs locally within the eye. In this article we describe a pulsed liquid microjet for minimally invasive intra-vascular drug delivery. The microjet is driven by a vapor bubble following an explosive evaporation of saline, produced by a microsecond-long electric discharge in front of the 25 micrometers electrode inside the micronozzle. Expansion of the transient vapor bubble produces a water jet with a diameter equal to the diameter of the nozzle, and with a velocity and duration that are controlled by the pulse energy. We found that fluid could be injected through the wall of a 60-micrometers -diameter artery in choriallantoic membrane using a 15-micrometers diameter liquid jet traveling at more than 60 m/s. Histological analysis of these arteries showed that the width of the perforation is limited to the diameter of the micronozzle, and the penetration depth of the jet is controlled by the discharge energy. The pulsed liquid microjet offers a promising technique for precise and needle-free intravascular delivery of thrombolytic drugs for localized treatment of retinal vascular occlusions.

  8. Improved Climatological Characterization of Optical Turbulence for Space Optical Imaging and Communications

    Science.gov (United States)

    Alliss, R.; Felton, B.

    2010-09-01

    including the Desert Southwest and Haleakala and Mauna Kea on Hawaii. A recent improvement to our modeling over Hawaii was performed by using a more representative land usage dataset. Simulations indicate that the vast lava fields which characterize the Big Island to the shoreline have a large impact on turbulence generation. The same turbulence characteristics are also present in the simulations on the Southeastern face of Haleakala. Turbulence is greatest during the daytime when the lava fields produce tremendous heat fluxes. Good agreement is found when the WRF simulations are compared to in situ data taken from the Thirty Meter Telescope (TMT) on Mauna Kea. The TMT study used a variety of seeing instruments which provided data day and night. Both the WRF simulations and TMT showed ro values bottoming out in the 3-4 cm range during daytime at Mauna Kea. Simulations are also performed over White Sands New Mexico and will be reported on at the conference. Results of these analyses are assisting engineers in developing state of the art adaptive optics designs. Detailed results of this study will be presented at the conference.

  9. Hyperbola-parabola primary mirror in Cassegrain optical antenna to improve transmission efficiency.

    Science.gov (United States)

    Zhang, Li; Chen, Lu; Yang, HuaJun; Jiang, Ping; Mao, Shengqian; Caiyang, Weinan

    2015-08-20

    An optical model with a hyperbola-parabola primary mirror added in the Cassegrain optical antenna, which can effectively improve the transmission efficiency, is proposed in this paper. The optimum parameters of a hyperbola-parabola primary mirror and a secondary mirror for the optical antenna system have been designed and analyzed in detail. The parabola-hyperbola primary structure optical antenna is obtained to improve the transmission efficiency of 10.60% in theory, and the simulation efficiency changed 9.359%. For different deflection angles to the receiving antenna with the emit antenna, the coupling efficiency curve of the optical antenna has been obtained.

  10. An Elderly Lady with Fever of Unknown Etiology and Severe Pulmonary Hypertension: Intravascular Lymphoma—An Elusive Diagnosis

    Directory of Open Access Journals (Sweden)

    Nupur Sinha

    2013-01-01

    Full Text Available Pulmonary hypertension (PH associated with malignancy, especially adenocarcinoma, is a well-known entity and is included in group V of the WHO classification. Intravascular lymphoma is a rare type of diffuse large B cell lymphoma, characterized by selective intravascular growth of malignant lymphocytes, aggressive behavior, and often a fatal course. Most of the time, diagnosis is postmortem due to the rarity and the protean manifestations of the disease. We present a rare case of an elderly patient presenting with severe pulmonary hypertension, fever of unknown etiology (FUO, and lymphadenopathy. Extensive evaluation searching for the etiology of her FUO and PH was noncontributory. The diagnosis of intravascular lymphoma was finally reached by the performance of a random abdominal fat pad biopsy and the patient was started on immunochemotherapy. She continues the follow up after 6 cycles of R-CHOP with no further febrile episodes and steady improvement in exercise tolerance.

  11. Improving the Performance of Three-Mirror Imaging Systems with Freeform Optics

    Science.gov (United States)

    Howard, Joseph M.; Wolbach, Steven

    2013-01-01

    The image quality improvement for three-mirror systems by Freeform Optics is surveyed over various f-number and field specifications. Starting with the Korsch solution, we increase the surface shape degrees of freedom and record the improvements.

  12. Multispectral Imager With Improved Filter Wheel and Optics

    Science.gov (United States)

    Bremer, James C.

    2007-01-01

    Figure 1 schematically depicts an improved multispectral imaging system of the type that utilizes a filter wheel that contains multiple discrete narrow-band-pass filters and that is rotated at a constant high speed to acquire images in rapid succession in the corresponding spectral bands. The improvement, relative to prior systems of this type, consists of the measures taken to prevent the exposure of a focal-plane array (FPA) of photodetectors to light in more than one spectral band at any given time and to prevent exposure of the array to any light during readout. In prior systems, these measures have included, variously the use of mechanical shutters or the incorporation of wide opaque sectors (equivalent to mechanical shutters) into filter wheels. These measures introduce substantial dead times into each operating cycle intervals during which image information cannot be collected and thus incoming light is wasted. In contrast, the present improved design does not involve shutters or wide opaque sectors, and it reduces dead times substantially. The improved multispectral imaging system is preceded by an afocal telescope and includes a filter wheel positioned so that its rotation brings each filter, in its turn, into the exit pupil of the telescope. The filter wheel contains an even number of narrow-band-pass filters separated by narrow, spoke-like opaque sectors. The geometric width of each filter exceeds the cross-sectional width of the light beam coming out of the telescope. The light transmitted by the sequence of narrow-band filters is incident on a dichroic beam splitter that reflects in a broad shorter-wavelength spectral band that contains half of the narrow bands and transmits in a broad longer-wavelength spectral band that contains the other half of the narrow spectral bands. The filters are arranged on the wheel so that if the pass band of a given filter is in the reflection band of the dichroic beam splitter, then the pass band of the adjacent filter

  13. Improved Large Segmented Optics Fabrication Using Magnetorheological Finishing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Primary mirrors for large aperture telescopes (>10m) are collections of smaller (1-2m), typically hexagonal, often aspheric, optical segments. NASA?s next...

  14. Customized data container for improved performance in optical cryptosystems

    Science.gov (United States)

    Vélez Zea, Alejandro; Fredy Barrera, John; Torroba, Roberto

    2016-12-01

    Coherent optical encryption procedures introduce speckle noise to the output, limiting many practical applications. Until now the only method available to avoid this noise is to codify the information to be processed into a container that is encrypted instead of the original data. Although the decrypted container presents the noise due to the optical processing, their features remain recognizable enough to allow decoding, bringing the original information free of any kind of degradation. The first adopted containers were the quick response (QR) codes. However, the limitations of optical encryption procedures and the features of QR codes imply that in practice only simple codes containing small amounts of data can be processed without large experimental requirements. In order to overcome this problem, we introduce the first tailor made container to be processed in optical cryptosystems, ensuring larger noise tolerance and the ability to process more information with less experimental requirements. We present both simulations and experimental results to demonstrate the advantages of our proposal.

  15. Do shorter wavelengths improve contrast in optical mammography?

    Science.gov (United States)

    Taroni, P.; Pifferi, A.; Torricelli, A.; Spinelli, L.; Danesini, G. M.; Cubeddu, R.

    2004-04-01

    The detection of tumours with time-resolved transmittance imaging relies essentially on blood absorption. Previous theoretical and phantom studies have shown that both contrast and spatial resolution of optical images are affected by the optical properties of the background medium, and high absorption and scattering are generally beneficial. Based on these observations, wavelengths shorter than presently used (680-780 nm) could be profitable for optical mammography. A study was thus performed analysing time-resolved transmittance images at 637, 656, 683 and 785 nm obtained from 26 patients bearing 16 tumours and 15 cysts. The optical contrast proved to increase upon decreasing wavelengths for the detection of cancers in late-gated intensity images, with higher gain in contrast for lesions of smaller size (decrease in contrast with wavelength was observed in scattering images.

  16. Towards Improved Cirrus Cloud Optical Depths from CALIPSO

    Science.gov (United States)

    Garnier, Anne; Vaughan, Mark; Pelon, Jacques; Winker, David; Trepte, Chip; Young, Stuart

    2016-06-01

    This paper reviews recent advances regarding the retrieval of optical depths of semi-transparent cirrus clouds using synergetic analyses of perfectly collocated observations from the CALIOP lidar and the IIR infrared radiometer aboard the CALIPSO satellite.

  17. Improved Large Segmented Optics Fabrication Using Magnetorheological Finishing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Primary mirrors for large aperture telescopes (> 10 m) are collections of smaller (1-2 m), typically hexagonal, often aspheric, optical segments. NASA's next...

  18. Intravascular ultrasound for angiographically indeterminant left main coronary artery disease.

    Science.gov (United States)

    Parashara, D K; Jacobs, L E; Ledley, G S; Yazdanfar, S; Oline, J; Kotler, M N

    1994-01-01

    The precise diagnosis of the presence of significant left main coronary artery disease has profound prognostic and therapeutic implications. Coronary cineangiography has shown to be imprecise and inaccurate to determine the percent stenosis of the left main coronary artery. We report a case with significant left main coronary artery disease in whom coronary cineangiography was in discordance with the clinical data and intravascular ultrasonography. Based on the intravascular ultrasound findings, the patient underwent coronary artery bypass graft surgery. Therefore, the intravascular ultrasonography may be the procedure of choice for assessing indeterminant left main coronary artery lesions by coronary angiography.

  19. Intravascular ultrasound radiofrequency analysis after optimal coronary stenting with initial quantitative coronary angiography guidance: An ATHEROREMO sub-study

    NARCIS (Netherlands)

    G. Sarno (Giovanna); S.A. Garg (Scot); J. Gomez-Lara (Josep); H.M. Garcia-Garcia (Hector); J.M.R. Ligthart (Jürgen); N. Bruining (Nico); Y. Onuma (Yoshinobu); K. Witberg (Karen); R.J.M. van Geuns (Robert Jan); S.P.M. de Boer (Sanneke); J.J. Wykrzykowska (Joanna); C.J. Schultz (Carl); H.J. Duckers (Henricus); E.S. Regar (Eveline); P.P.T. de Jaegere (Peter); P.J. de Feyter (Pim); G.A. van Es (Gerrit Anne); H. Boersma (Eric); W.J. van der Giessen (Wim); P.W.J.C. Serruys (Patrick)

    2011-01-01

    textabstractAims: To investigate whether the use of intravascular ultrasound virtual histology (IVUS-VH) leads to any improvements in stent deployment, when performed in patients considered to have had an optimal percutaneous coronary intervention (PCI) by quantitative coronary angiography (QCA). Me

  20. Intravascular Ultrasound Image Segmentation Using Morphological Snakes

    Directory of Open Access Journals (Sweden)

    Hamdi Mohamed Ali

    2012-06-01

    Full Text Available From the first use of the technics of intravascular ultrasound (IVUS as an imaging technique for the coronary artery system at the 70th century until now , the segmentation of the arterial wall boundaries still an important problem . Much research has been done to give better segmentation result for better diagnostics , evaluation and therapy planning. In this paper we present a new segmentation technics based on Morphological Snakes which developed by Luis Álvarez used for the first time for IVUS segmentation. It is a simple , fast and stable approach of snakes evolution algorithm. Results are presented and discussed in order to demonstrate the effectiveness of this approach in IVUS segmentation.

  1. Quinine-Induced Disseminated Intravascular Coagulation

    Directory of Open Access Journals (Sweden)

    Firas Abed

    2016-01-01

    Full Text Available Every drug comes with some side effect. It is the benefit/risk ratio that determines the medical use of the drug. Quinine, a known antimalarial drug, has been used for nocturnal leg cramps since the 1930s; it is associated with severe life-threatening hematological and cardiovascular side effects. Disseminated intravascular coagulation (DIC, albeit rare, is a known coagulopathy associated with Quinine. It is imperative to inquire about the Quinine intake in medication history in patients with coagulopathy, as most patients still consider it a harmless home remedy for nocturnal leg cramps. In this report, we present a case of coagulopathy in a middle-aged woman, who gave a history of taking Quinine for nocturnal leg cramps, as her home remedy. Early identification of the offending agent led to the diagnosis, prompt discontinuation of the medication, and complete recovery and prevented the future possibility of recurrence.

  2. Disseminated intravascular coagulation in burn injury.

    Science.gov (United States)

    Lippi, Giuseppe; Ippolito, Luigi; Cervellin, Gianfranco

    2010-06-01

    Disseminated intravascular coagulation (DIC) is a complex and multifaceted disorder characterized by the activation of coagulation and fibrinolytic pathways, consumption of coagulation factors, and depletion of coagulation regulatory proteins. The introduction into the circulation of cellular debris characterized by strong thromboplastic activity due to tissue factor exposition or release (in or from burned tissues), which can thereby activate extrinsic pathway of coagulation system and trigger massive thrombin generation when present in sufficient concentration, represents the most plausible biological explanation to support the development of intravascular coagulation in patients with burn injury. Severe burns left untreated might also lead to an immunological and inflammatory response (activation of the complement cascade), which can amplify fibrinolysis and blood clotting. Overall, the real prevalence of DIC in patients with burns is as yet unclear. Postmortem, retrospective, and even longitudinal investigations are in fact biased by several factors, such as the objective difficulty to establish whether DIC might have occurred as a primary complication of burns or rather as a consequence of other superimposed pathologies (e.g., sepsis, multiple organ failure), the different diagnostic criteria for assessing DIC, and the heterogeneity of the patient samples studied. Nevertheless, the current scientific evidence is consistent with the hypothesis that biochemical changes suggestive for DIC (hypercoagulability, hypo- and hyperfibrinolysis) are commonplace in patients with burn trauma, and their severity increases exponentially with the severity of injury. Overt DIC seems to occur especially in critically ill burn patients or in those with severe burns (up to third degree) and large involvement of body surface area, in whom an appropriate therapy might be effective to prevent the otherwise fulminant course. Although early prophylaxis with antithrombin concentrates

  3. Optical Vector Network Analyzer with an Improved Dynamic Range Based on a Polarization Multiplexing Electro-Optic Modulator

    Science.gov (United States)

    Wang, Qi; Wang, Wen-Ting; Chen, Wei; Liu, Jian-Guo; Zhu, Ning-Hua

    2017-05-01

    We present a new method to achieve an optical vector network analyzer (OVNA) based on a polarization multiplexing electro-optic modulator (PM-EOM) without an optical bandpass filter. Optical single sideband (OSSB) modulated signals with a tunable optical carrier-sideband ratio (OCSR) are obtained at the output of the PM-EOM. The OCSR can be flexibly tuned by controlling bias voltages of the PM-EOM. The dynamic range of the OVNA is expanded by taking the improvement of the OCSR into account. The transmission response of an optical device under test (ODUT) is measured based on one-to-one mapping from optical domain to electrical domain. By optimizing the OCSR of the OSSB modulated signals, the dynamic range of the OVNA can be effectively improved with 3.7 dB. An analytical model is derived to describe the transfer function of the ODUT. The magnitude and phase responses of a fiber Bragg grating are characterized with a large dynamic range. Supported by the National Natural Science Foundation of China under Grant Nos 61377070, 61090391 and 61675196, and the National High-Technology Research and Development Program of China under Grant No 2013AA014203.

  4. Improved Framework for Tractography Reconstruction of the Optic Radiation.

    Directory of Open Access Journals (Sweden)

    Eloy Martínez-Heras

    Full Text Available The optic radiation (OR is one of the major components of the visual system and a key structure at risk in white matter diseases such as multiple sclerosis (MS. However, it is challenging to perform track reconstruction of the OR using diffusion MRI due to a sharp change of direction in the Meyer's loop and the presence of kissing and crossing fibers along the pathway. As such, we aimed to provide a highly precise and reproducible framework for tracking the OR from thalamic and visual cortex masks. The framework combined the generation of probabilistic streamlines by high order fiber orientation distributions estimated with constrained spherical deconvolution and an automatic post-processing based on anatomical exclusion criteria (AEC to compensate for the presence of anatomically implausible streamlines. Specifically, those ending in the contralateral hemisphere, cerebrospinal fluid or grey matter outside the visual cortex were automatically excluded. We applied the framework to two distinct high angular resolution diffusion-weighted imaging (HARDI acquisition protocols on one cohort, comprised of ten healthy volunteers and five MS patients. The OR was successfully delineated in both HARDI acquisitions in the healthy volunteers and MS patients. Quantitative evaluation of the OR position was done by comparing the results with histological reference data. Compared with histological mask, the OR reconstruction into a template (OR-TCT was highly precise (percentage of voxels within the OR-TCT correctly defined as OR, ranging from 0.71 to 0.83. The sensitivity (percentage of voxels in histological reference mask correctly defined as OR in OR-TCT ranged from 0.65 to 0.81 and the accuracy (measured by F1 score was 0.73 to 0.77 in healthy volunteers. When AEC was not applied the precision and accuracy decreased. The absolute agreement between both HARDI datasets measured by the intraclass correlation coefficient was 0.73. This improved framework

  5. Subharmonic Contrast Intravascular Ultrasound for Vasa Vasorum Imaging

    NARCIS (Netherlands)

    Goertz, David E.; Frijlink, Martijn E.; Tempel, Dennie; Bhagwandas, Vijay; Gisolf, Andries; Krams, Robert; Jong, de Nico; Steen, van der Antonius F.W.

    2007-01-01

    The feasibility of subharmonic contrast intravascular ultrasound (IVUS) imaging was investigated using a prototype nonlinear IVUS system and the commercial contrast agent Definity™. The system employed a mechanically scanned commercial catheter with a custom transducer element fabricated to have sen

  6. Adaptive optics for improved retinal surgery and diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Humayun, M S; Sadda, S R; Thompson, C A; Olivier, S S; Kartz, M W

    2000-08-21

    It is now possible to field a compact adaptive optics (AO) system on a surgical microscope for use in retinal diagnostics and surgery. Recent developments in integrated circuit technology and optical photonics have led to the capability of building an AO system that is compact and significantly less expensive than traditional AO systems. It is foreseen that such an AO system can be integrated into a surgical microscope while maintaining a package size of a lunchbox. A prototype device can be developed in a manner that lends itself well to large-scale manufacturing.

  7. A systematic analysis of the optical merit function landscape: towards improved optimization methods in optical design

    NARCIS (Netherlands)

    Van Turnhout, M.

    2009-01-01

    A major problem in optical system design is that the optical merit function landscape is usually very complicated, especially for complex design problems where many minima are present. Finding good new local minima is then a difficult task. We show however that a certain degree of order is present i

  8. Improved axial position detection in optical tweezers measurements

    DEFF Research Database (Denmark)

    Dreyer, Jakob Kisbye; Berg-Sørensen, Kirstine; Oddershede, Lene

    2004-01-01

    We investigate the axial position detection of a trapped microsphere in an optical trap by using a quadrant photodiode. By replacing the photodiode with a CCD camera, we obtain detailed information on the light scattered by the microsphere. The correlation of the interference pattern with the axial...

  9. Improved stress prediction in adhesive bonded optical components

    NARCIS (Netherlands)

    Vreugd, J. de; Voert, M.J.A. te; Nijenhuis, J.R.; Pijnenburg, J.A.C.M.; Tabak, E.

    2012-01-01

    Adhesives are widely used in optomechanical structures for bonding optical components to their mounts. The main advantage of using adhesives is the excellent strength to weight ratio. Adhesive bonding is seen as a desirable joining technique as it allows for greater flexibility in design. A disadvan

  10. Intravascular Large B-Cell Lymphoma Diagnosed on Prostate Biopsy: A Case Report

    Directory of Open Access Journals (Sweden)

    Nazan Özsan

    2014-12-01

    Full Text Available Intravascular large B-cell lymphoma (IVLBCL is a very rare type of non-Hodgkin lymphoma, usually affecting elderly patients and characterized by selective infiltration of neoplastic cells within blood vessels’ lumina. IVLBCL diagnosed with prostatic involvement is extremely rare. We report a patient of 65 years old, having mostly neurological complaints but diagnosed with IVLBCL upon histopathological examination of transurethral prostate resection material, which revealed large neoplastic cell infiltration totally limited within the lumens of small vessels. By immunohistochemistry, neoplastic cell infiltration was positive with MUM1, bcl-6, and bcl-2 and negative with ALK1, CD10, and CD30, with a high Ki-67 proliferation index. CD34 and CD31 staining showed expression in endothelial cells, highlighting the intravascular nature of neoplastic infiltrate. The patient unfortunately refused to receive treatment and died of the disease 8 months after the diagnosis. IVLBCL, though very rare, should be considered in differential diagnosis of all organ biopsies with intravascular infiltration. Further improvements in the understanding of the pathogenesis and biology of this rare type of lymphoma are mandatory.

  11. Comparative study of the intravascular ultrasound and optical coherence tomography in stenting strategy selection and its prognostic impact in coronary bifurcation lesions%血管内超声与光学相干断层显像对冠状动脉分叉病变手术策略及预后影响的对照研究

    Institute of Scientific and Technical Information of China (English)

    殷拥军; 孔令秋; 张宏才; 伍洲; 赵珏; 黄大军; 许勇; 聂谦

    2016-01-01

    Objective To investigate the reliability of the intravascular ultrasound(IVUS)and optical coherence tomography(OCT)in stenting strategy selection and its prognostic impact in coronary bifurcation lesions.Methods A total of 157 patients with coronary artery disease were prospectively studied by using angiography,OCT,and IVUS. Quantitative image analyses of the coronary bifurcation lesions were performed.The stenting strategy selection and its prognostic impact were evaluated.Results In the clinical study,the mean minimum lumen diameter(MLD)and the minimum lumen area(MLA) measured by QCA were significantly smaller than those measured by IVUS and OCT (P 0.05),although the OCT seems better in the follow-up.Conclusions IVUS and OCT provide accurate and reproducible quantitative measurements of coronary artery,all of them were reliable in stenting strategy selection.%目的:对比血管内超声(IVUS)及光学相干断层显像(OCT)对冠状动脉分叉病变经皮冠状动脉介入治疗(PCI)手术策略选择及预后的影响。方法冠状动脉造影明确为分叉病变的患者157例,使用冠状动脉定量分析(QCA)测量最小管腔直径(MLD)、最小管腔横截面积(MLA)、参照管腔直径(RLD),其后随机进行 IVUS (84例)和 OCT检查(73例),测量并比较上述参数与 QCA测值的差异;比较不同方法所指导的支架植入方案心血管事件发生率。结果通过 IVUS 及 OCT 所测冠状动脉 MLD、MLA、RLD 均高于 QCA 法,其中 MLD、MLA 差异有统计学意义(P 0.05)。结论IVUS 和OCT 均可用于指导分叉病变患者PCI 策略选择。

  12. Intravascular ultrasonic-photoacoustic (IVUP) endoscope with 2.2-mm diameter catheter for medical imaging.

    Science.gov (United States)

    Bui, Nhat Quang; Hlaing, Kyu Kyu; Nguyen, Van Phuc; Nguyen, Trung Hau; Oh, Yun-Ok; Fan, Xiao Feng; Lee, Yong Wook; Nam, Seung Yun; Kang, Hyun Wook; Oh, Junghwan

    2015-10-01

    Intravascular ultrasound (IVUS) imaging is extremely important for detection and characterization of high-risk atherosclerotic plaques as well as gastrointestinal diseases. Recently, intravascular photoacoustic (IVPA) imaging has been used to differentiate the composition of biological tissues with high optical contrast and ultrasonic resolution. The combination of these imaging techniques could provide morphological information and molecular screening to characterize abnormal tissues, which would help physicians to ensure vital therapeutic value and prognostic significance for patients before commencing therapy. In this study, integration of a high-frequency IVUS imaging catheter (45MHz, single-element, unfocused, 0.7mm in diameter) with a multi-mode optical fiber (0.6mm in core diameter, 0.22 NA), an integrated intravascular ultrasonic-photoacoustic (IVUP) imaging catheter, was developed to provide spatial and functional information on light distribution in a turbid sample. Simultaneously, IVUS imaging was co-registered to IVPA imaging to construct 3D volumetric sample images. In a phantom study, a polyvinyl alcohol (PVA) tissue-mimicking arterial vessel phantom with indocyanine green (ICG) and methylene blue (MB) inclusion was used to demonstrate the feasibility of mapping the biological dyes, which are used in cardiovascular and cancer diagnostics. For the ex vivo study, an excised sample of pig intestine with ICG was utilized to target the biomarkers present in the gastrointestinal tumors or the atherosclerotic plaques with the proposed hybrid technique. The results indicated that IVUP endoscope with the 2.2-mm diameter catheter could be a useful tool for medical imaging. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Intravascular Large B-Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    Maria S. Khan MD, FACP

    2014-03-01

    Full Text Available Case Presentation. A 69-year-old Hispanic male, with a past history of diabetes and coronary disease, was admitted for fever, diarrhea, and confusion of 4 weeks duration. Physical examination showed a disoriented patient with multiple ecchymoses, possible ascites, and bilateral scrotal swelling. Hemoglobin was 6.7, prothrombin time (PT 21.4 seconds with international normalized ratio 2.1, partial thromboplastin time (PTT 55.6 seconds, fibrin split 10 µg/L, and lactate dehydrogenase (LDH 1231 IU/L. Except for a positive DNA test for Epstein–Barr virus (EBV infection, extensive diagnostic workup for infections, malignancy, or a neurological cause was negative. Mixing studies revealed a nonspecific inhibitor of PT and PTT but Factor VIII levels were normal. The patient was empirically treated with antibiotics but developed hypotension and died on day 27 of admission. At autopsy, patient was found to have intravascular diffuse large B-cell lymphoma involving skin, testes, lung, and muscles. The malignant cells were positive for CD20, CD791, Mum-1, and Pax-5 and negative for CD3, CD5, CD10, CD30, and Bcl-6. The malignant cells were 100% positive for Ki-67. Discussion. Intravascular large cell B-cell lymphoma (IVLBCL is rare form of diffuse large B-cell lymphoma and tends to proliferate within small blood vessels, particularly capillaries and postcapillary venules. The cause of its affinity for vascular bed remains unknown. In many reports, IVLBCL was associated with HIV, HHV8, and EBV infections. The fact that our case showed evidence of EBV infection lends support to the association of this diagnosis to viral illness. The available literature on this subject is scant, and in many cases, the diagnosis was made only at autopsy. The typical presentation of this disorder is with B symptoms, progressive neurologic deficits, and skin findings. Bone marrow, spleen, and liver are involved in a minority of patients. Nearly all patients have elevated LDH

  14. Improved electroabsorption demultiplexer by tandem-arrangement with semiconductor optical amplifier

    DEFF Research Database (Denmark)

    Hilliger, E.; Marembert, V.; Schubert, C.

    2002-01-01

    An electroabsorption demultiplexer was improved by operating it in a tandem-arrangement with an optically controlled SOA. An increase of the maximum data rate from 40 Gbit/s to 80 Gbit/s was experimentally demonstrated. The main drawback of the proposed scheme is the need of an additional optical...

  15. Improving acousto-optical interaction by high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard

    In recent years experiments have shown that optical waves in waveguides can be modulated by mechanical stresses from surface acoustic waves (SAW), which have most of their energy density concentrated at the surface. In these experiments the SAWs are generated in piezoelectric materials...... by conventional interdigital transducers consisting of thin electrodes deposited at the surface. In this work the finite element method is employed to investigate if the acousto-optical interaction can be enhanced by generating the SAWs by interdigital transducers consisting of high aspect ratio electrodes....... With a periodic model it is first shown that these tall electrodes introduce several new confined SAW modes with slow phase velocities because of mechanical energy storage in the electrodes. The periodic model is then extended to a finite model by using perfectly matched layers at the substrate borders...

  16. Optical Tweezers and Optical Trapping Improved for Future Automated Micromanipulation and Characterization

    Science.gov (United States)

    Wrbanek, Susan Y.; Decker, Arthur J.

    2005-01-01

    Optical trap arrays are being developed at the NASA Glenn Research Center for holding, manipulating, and optically interrogating arrays of nanotube sensors. The trap arrays, for example, might be used to arrange arrays of chemical sensors for insertion onto a chip in liquid, air, and vacuum environments. Neural-network-controlled spatial light modulators (SLMs) are to generate and control the trap positions and trap profiles in three dimensions.

  17. Brighter near-field optical probes by means of improving the optical destruction threshold.

    Science.gov (United States)

    Stöckle, R M; Schaller, N; Deckert, V; Fokas, C; Zenobi, R

    1999-01-01

    The optical destruction thresholds of conventionally etched and tube-etched near-field optical probes were measured. One of the main advantages of tube-etched tips is their smooth glass surface after taper formation. Presumably for this reason, a destruction limit of over 120 microJ was obtained, almost twice as large as that of the rougher, conventionally etched fibre probes. The use of additional adhesion layers (Ti. Cr, Co and Ni) between the glass surface and the aluminium coating produced, especially for tube-etched tips, a significant increase in the optical destruction threshold. With increasingly thin metal coatings, the use of a protection coating that prevents corrosion during aging is recommended. An additional increase in optical stability was achieved by applying mixed-metal coatings: alternating thin titanium and thick aluminium layers yielded fibre probes with superior properties that achieved average optical destruction thresholds of > 270 microJ. This is an increase in stability of > 400% compared with conventionally fabricated near-field optical tips.

  18. An Improved MAC Scheme of HORNET Based on Node Structure with Variable Optical Buffer

    Institute of Scientific and Technical Information of China (English)

    Nian Fang; Lutang Wang; Zhaoming Huang

    2003-01-01

    An improved unslotted CSMA/CA MAC scheme of HORNET based on the node structure with variable optical buffer is reported. It can be used for transmitting high effectively all variable IP packets in the WDM network.

  19. Improvement of a polarized alkali ion source by means of optical pumping

    Energy Technology Data Exchange (ETDEWEB)

    Dreves, W.; Koch, E.; Jaensch, H.; Kamke, W.; Broermann, W.; Fick, D.

    1982-01-01

    A source for polarized alkali ions can be improved considerably by optical pumping of the atom beam in combination with a modified weak field transition. M-level populations were investigated using laser induced fluorescence in a magnetic field.

  20. An improved resource allocation algorithm based on double auction for optical networks

    Science.gov (United States)

    Duan, Xiaolin; Yang, Xiaolong; Shen, Huang; Chen, Qianbin

    2007-11-01

    For the resource allocation of optical network, grid economy can be introduced to optimize the utilization of resource. Double auction algorithm is appropriate for grid economy, but the speed of convergence of many algorithms is too slow. In this paper we proposed double auction supported optical resource scheduling framework, and then described an improved algorithm on double auction based resource allocation for optical network. We attempt to speed the course of auction and utilize price parameter to adjust the overlay. Simulation results show that our scheme can optimize the equilibrium of overlay, and optical resource can be allocated and scheduled efficiently.

  1. Laboratory testing in disseminated intravascular coagulation.

    Science.gov (United States)

    Favaloro, Emmanuel J

    2010-06-01

    The diagnosis of disseminated intravascular coagulation (DIC) relies on clinical signs and symptoms, identification of the underlying disease, the results of laboratory testing, and differentiation from other pathologies. The clinical features mainly depend on the underlying cause of the DIC. The laboratory diagnosis of DIC uses a combination of tests because no single test result alone can firmly establish or rule out the diagnosis. Global tests of hemostasis may initially provide evidence of coagulation activation and later in the process provide evidence of consumption of coagulation factors, but their individual diagnostic efficiency is limited. Fibrinolytic markers, in particular D-dimer, are reflective of activation of both coagulation and fibrinolysis, so that a normal finding can be useful for ruling-out DIC. Decreased levels of the natural anticoagulants (in particular, antithrombin and protein C) are frequently observed in patients with DIC, but their measurement is not normally incorporated into standard diagnostic algorithms. New tests are being explored for utility in DIC, and some additional tests may be useful on a case-by-case basis, depending on the proposed cause of the DIC or their local availability. For example, clot waveform analysis is useful but currently limited to a single instrument. Also, procalcitonin is an inflammatory biomarker that may be useful within the context of septic DIC, and activated factor X clotting time is an emerging test of procoagulant phospholipids that also seems to hold promise in DIC.

  2. Primary intravascular synovial sarcoma: case report.

    Science.gov (United States)

    Tuncer, Osman Nuri; Erbasan, Ozan; Golbasi, Ilhan

    2012-10-01

    Synovial sarcoma (SS), a mesenchymal spindle cell tumor, displays variable epithelial differentiation, including glandular formation, and features a specific chromosomal translocation, t(X;18)(p11;q11). SS accounts for 5% to 10% of soft-tissue sarcomas. These tumors occur mostly in the joints, especially near the knee, but they also occur in other locations. Primary intravascular SS (IVSS) are extremely rare; only 6 well-documented cases have been reported in the English literature. We describe a new case of primary IVSS of the superior vena cava (SVC) in a 16-year-old boy. A transthoracic echocardiogram confirmed a large (4.8 × 4.6 cm) circumscribed mass filling the right atrium, as well as a moderate pericardial effusion. The mass extended from the SVC to the tricuspid valve but did not prevent valve coaptation. Surgery via a transatrial approach revealed a huge mass (8 to 12 cm) attached to the SVC via a 5-mm pedicle. The tumor was excised, and the patient experienced an uneventful postoperative course. Fluorescence in situ hybridization analysis revealed the presence of the SS-specific translocation.

  3. Toward a Continuous Intravascular Glucose Monitoring System

    Directory of Open Access Journals (Sweden)

    Pedro Irazoqui

    2010-12-01

    Full Text Available Proof-of-concept studies that display the potential of using a glucose-sensitive hydrogel as a continuous glucose sensor are presented. The swelling ratio, porosity, and diffusivity of the hydrogel increased with glucose concentration. In glucose solutions of 50, 100, 200, and 300 mg/dL, the hydrogel swelling ratios were 4.9, 12.3, 15.9, and 21.7, respectively, and the swelling was reversible. The impedance across the hydrogel depended solely on the thickness and had an average increase of 47 W/mm. The hydrogels exposed to a hyperglycemic solution were more porous than the hydrogels exposed to a normal glycemic solution. The diffusivity of 390 Da MW fluorescein isothiocyanate in hydrogels exposed to normal and hyperglycemic solutions was examined using fluorescence recovery after photobleaching and was found to be 9.3 × 10−14 and 41.4 × 10−14 m2/s, respectively, compared to 6.2 × 10−10 m2/s in glucose solution. There was no significant difference between the permeability of hydrogels in normal and hyperglycemic glucose solutions with averages being 5.26 × 10−17 m2 and 5.80 × 10−17 m2, respectively, which resembles 2–4% agarose gels. A prototype design is presented for continuous intravascular glucose monitoring by attaching a glucose sensor to an FDA-approved stent.

  4. Meta-analysis on intravascular low energy laser therapy

    Science.gov (United States)

    Zhao, Shu-Dong; Liu, Timon Cheng-Yi; Wang, Yan-Fang; Liu, Song-Hao

    2008-12-01

    Intravascular low energy laser therapy (ILELT) was put forward for cardiocirculatory diseases in USA in 1982, was popular in Russia in 1980s, and then in China in 1990s. The therapeutic effects of ILELT and drugs in comparison with drugs only on Chinese patients and their blood parameters were analyzed with meta-analyses and reported as (OR, 95%CI) for patient improvement and (WMD, 95% CI) for blood parameter improvement, where 95%CI, OR and WMD denoted 95% confidence intervals, odds ratio and weighted mean difference, respectively. It was found that the patients of cerebral infarction (2.39, 2.09~2.74) and cerebrovascular diseases (2.97, 1.69~2.53) were cured, respectively, (P low density lipoprotein cholesterol (-0.6, -1.01~-0.19), triacylglycerol (0.63, -0.83~-0.42), high density lipoprotein (0.34, 0.10~0.59), erythrocyte aggregation index (-0.24, -0.27~-0.21), erythrocyte Sedimentation Rate (-4.57, -7.26~-1.89), fibrinogen (-0.76, -1.31~-0.21), whole blood contrast viscosity (-0.40, -0.69~-0.12), low cut blood viscosity (-1.2, -1.93~-0.48), high cut blood viscosity (-0.62, -0.92~-0.32), whole blood viscosity(-1.2, -1.85~-0.54) and plasma blood contrast viscosity(-0.07, -0.12~-0.03) were found improved (P < 0.05). It is concluded that the patients of cerebral infarction, cerebrovascular diseases and diabetes might be improved with ILELT, which might be mediated by blood parameter improvement.

  5. Investigation on Characteristics and the Improving Method of Double Loop Optical Buffer

    Institute of Scientific and Technical Information of China (English)

    WANG Yong-Jun; WU Chong-Qing; WANG Zhi; YANG Shuang-Shou; ZHAO Shuang; WANG Ya-Ping; SHU Da; ZHAO Xi

    2009-01-01

    @@ We establish an equivalent cascaded semiconductor optical amplifier system model to analyze the characteristics of the double loop optical buffer (DLOB). The theoretical analysis finds that the performance of the DLOB can be improved by inserted amplifying process in an interval of some cycles. The experiment demonstrates that the buffered cycles can be improved from 20 to 50 and the bit error rate is less than 10-9 by inserting amplifying process in an interval of about 10 cycles.

  6. Exploring Techniques for Improving Retrievals of Bio-optical Properties of Coastal Waters

    Science.gov (United States)

    2013-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Exploring Techniques for Improving Retrievals of Bio ...Exploring Techniques for Improving Retrievals of Bio -optical Properties of Coastal Waters 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...retrieval of bio -optical properties, benefits from the leveraging of funding by NOAA CREST in which remote sensing of coastal waters is an important

  7. Improving the Optical Quality Factor of the WGM Resonator

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Iltchenko, Vladimir

    2008-01-01

    Resonators usually are characterized with two partially dependent values: finesse (F) and quality factor (Q). The finesse of an empty Fabry-Perot (FP) resonator is defined solely by the quality of its mirrors and is calculated as F=piR(exp 1/2)/(1-R). The maximum up-to-date value of reflectivity R approximately equal to 1 - 1.6 x 10(exp -6) is achieved with dielectric mirrors. An FP resonator made with the mirrors has finesse F=1.9 x 10(exp 6). Further practical increase of the finesse of FP resonators is problematic because of the absorption and the scattering of light in the mirror material through fundamental limit on the reflection losses given by the internal material losses and by thermodynamic density fluctuations on the order of parts in 109. The quality factor of a resonator depends on both its finesse and its geometrical size. A one-dimensional FP resonator has Q=2 F L/lambda, where L is the distance between the mirrors and lambda is the wavelength. It is easy to see that the quality factor of the resonator is unlimited because L is unlimited. F and Q are equally important. In some cases, finesse is technically more valuable than the quality factor. For instance, buildup of the optical power inside the resonator, as well as the Purcell factor, is proportional to finesse. Sometimes, however, the quality factor is more valuable. For example, inverse threshold power of intracavity hyperparametric oscillation is proportional to Q(exp 2) and efficiency of parametric frequency mixing is proportional to Q(exp 3). Therefore, it is important to know both the maximally achievable finesse and quality factor values of a resonator. Whispering gallery mode (WGM) resonators are capable of achieving larger finesse compared to FP resonators. For instance, fused silica resonators with finesse 2.3 x 10(exp 6) and 2.8 x 10(exp 6) have been demonstrated. Crystalline WGM resonators reveal even larger finesse values, F=6.3 x 10(exp 6), because of low attenuation of light in the

  8. Improved optical amplification using metamaterial based split ring structures in optical fibres

    Science.gov (United States)

    Prakash, Geetha; Nigam, Raaghvam; Das, Sovan; Chellappa, Sharath

    2016-04-01

    Optical fibres provide the best solutions for transmitting high speed, large amounts of data with good power efficiency. However such transmission would also need amplification for transmission over large distances. Erbium Doped Fibre Amplifiers(EDFAs) are currently being used for optical amplification. But good amplification is achievable with multiple stages and considerable length of EDFA fibres. In this paper we compare the use of Silver Split Ring Resonators(SRRs) , Gold Nano Rods and Silver Fishnet structures which give metamaterial properties to be used in optical fibres to give better amplification than EDFA based fibres. Metamaterials belong to a new class of materials with negative values for permittivity and permeability. Such materials would exhibit negative refractive index leading to these materials being called as left handed media.If such left handed media have an internal structure made of dimensions much smaller than the wavelength but sufficiently thick to exhibit bulk properties, using other optical domains such as plasmonics, it is possible to control light interactions and propagation. Artificial structures smaller than the wavelength of light can be used to enhance electric and magnetic fields. Surface plasmons can be excited on a metal and this can enhance the electric field at the surface. Our paper proposes the use of this phenomenon of achieving gain at optical frequencies by using SRRs, Fishnet structures , Nano Rods. We compare the performance of these structures and observe that they provide gain which is much more than that provided by EDFAs.

  9. Quantum Sensors: Improved Optical Measurement via Specialized Quantum States

    Directory of Open Access Journals (Sweden)

    David S. Simon

    2016-01-01

    Full Text Available Classical measurement strategies in many areas are approaching their maximum resolution and sensitivity levels, but these levels often still fall far short of the ultimate limits allowed by the laws of physics. To go further, strategies must be adopted that take into account the quantum nature of the probe particles and that optimize their quantum states for the desired application. Here, we review some of these approaches, in which quantum entanglement, the orbital angular momentum of single photons, and quantum interferometry are used to produce optical measurements beyond the classical limit.

  10. Using single photons to improve fiber optic communication systems

    Science.gov (United States)

    Pinto, Armando N.; Silva, Nuno A.; Almeida, Álvaro J.; Muga, Nelson J.

    2014-08-01

    We show how to generate, encode, transmit and detect single photons. By using single photons we can address two of the more challenging problems that communication engineers face nowadays: capacity and security. Indeed, by decreasing the number of photons used to encode each bit, we can efficiently explore the full capacity to carry information of optical fibers, and we can guarantee privacy at the physical layer. We present results for single and entangled photon generation. We encode information in the photons polarization and after transmission we retrieve that information. We discuss the impact of fiber birefringence on the photons polarization.

  11. [Progress in diagnosis and treatment for disseminated intravascular coagulation].

    Science.gov (United States)

    Wada, Hideo; Matsumoto, Takeshi; Aota, Takumi; Yamashita, Yoshiki

    2015-02-01

    As the development of a hypercoagulable state in the setting of disseminated intravascular coagulation (DIC) induces localized infection, therapy for DIC should be evaluated according to the findings of examinations for both severe sepsis and DIC. DIC is classified into the following types: "bleeding type," "organ failure type," "asymptomatic type," and "complication type." The "bleeding type" and "organ failure type" are considered to reflect the "plasmin inhibitor (PI) deficiency type" and "antithrombin (AT) deficiency type," respectively. In order to improve the diagnosis of DIC, in particular limitations in global coagulation tests, the Japanese Society of Thrombosis and Hemostasis recently proposed tentative diagnostic criteria for DIC using hemostatic molecular markers and AT. The recommendations for treatment of DIC, especially the use of AT concentrates, recombinant activated protein C and thrombomodulin, vary among several guidelines for the management of DIC. These agents inhibit the effects of key proteases in activating coagulation and consequently exert an anti-inflammatory effect on DIC. Hence, it is necessary to extensively evaluate these agents in well-conducted clinical trials.

  12. Back to the future: testing in disseminated intravascular coagulation.

    Science.gov (United States)

    Toh, Cheng-Hock; Downey, Colin

    2005-11-01

    Following on from the first clinical observations on disseminated intravascular coagulation (DIC) in the nineteenth century, the dawn of laboratory testing for DIC began with the availability of assays that characterized the extrinsic and intrinsic pathways of coagulation. Markedly increased clotting times were the hallmark of DIC. As the understanding of the biochemistry of haemostasis and thrombosis improved, new tests were developed based on the molecular players that participate in the process. However, many are non-specific for DIC and/or are unwieldy in performance to keep apace with the demands of the acute clinical setting. The renewed emphasis in DIC for the modern laboratory of the twenty-first century has seen a return to the simple, rapid and practical global tests of coagulation within scoring systems that also capture the pathophysiological continuum by trend analysis. Additionally, new technologies based on these simple tests of coagulation hold promise in also indicating the in vivo interplay between coagulation and inflammation during DIC.

  13. Subharmonic contrast intravascular ultrasound for vasa vasorum imaging.

    Science.gov (United States)

    Goertz, David E; Frijlink, Martijn E; Tempel, Dennie; Bhagwandas, Vijay; Gisolf, Andries; Krams, Robert; de Jong, Nico; van der Steen, Antonius F W

    2007-12-01

    The feasibility of subharmonic contrast intravascular ultrasound (IVUS) imaging was investigated using a prototype nonlinear IVUS system and the commercial contrast agent Definity . The system employed a mechanically scanned commercial catheter with a custom transducer element fabricated to have sensitivity at both 15 and 30 MHz. Experiments were conducted at a fundamental frequency of 30 MHz (F30; 25% bandwidth), with on-axis pressures ranging from 0.12 to 0.79 MPa, as measured with a needle hydrophone. In vitro characterization experiments demonstrated the detection of 15 MHz subharmonic signals (SH15) when pressure levels reached 360 kPa. The formation of SH15 images was shown, with tissue signals suppressed to near the noise floor and contrast to tissue ratios were improved by up to 30 dB relative to F30. In vivo experiments were performed using the atherosclerotic rabbit aorta model. Following the bolus injection of contrast agent upstream of the imaging catheter, agent was detected within the aorta, vena cava and within the perivascular space. These results provide a first in vivo demonstration of subharmonic contrast IVUS and suggest its potential as a new technique for imaging vasa vasorum.

  14. Progressive multifocal cerebral infarction from intravascular large B cell lymphoma presenting in a man: a case report

    Directory of Open Access Journals (Sweden)

    Chotinaiwattarakul Wattanachai

    2011-01-01

    Full Text Available Abstract Introduction Intravascular lymphoma is rare, and may present as ischemic stroke. Diagnosis is difficult due to the non-specific presentation and lack of lymphadenopathy, thus leading to frequent instances of autopsy-proven diagnosis. To the best of our knowledge, this is the first report of progressive stroke from intravascular lymphoma diagnosed antemortem by random skin biopsy. Case presentation A 42-year-old Thai man presented to our hospital with progressive multifocal cerebral infarction. Despite taking aspirin (300 mg/day, his neurological symptoms worsened. During admission, he developed an unexplained fever and hypoxemia. Magnetic resonance angiography clearly showed patency of all cerebral arteries including the internal carotid and vertebrobasilar arteries. Echocardiography, an antiphospholipid antibody test, cerebrospinal fluid cytology and a bone marrow study were normal. Other laboratory test results showed an elevated lactate dehydrogenase level, nephrotic range proteinuria (3.91 g/day, hypoalbuminemia (1.9 g/dL, a very low high-density lipoprotein level (7 mg/dL and hypertriglyceridemia (353 mg/dL. Because of suspected vasculitis, pulse methylprednisolone was given with transiently minimal improvement. A random skin biopsy from both thighs revealed intravascular large B cell lymphoma. Chemotherapy was not given due to our patient having ventilator associated pneumonia. He died 10 days after the definite diagnosis was established. Conclusion One etiology of stroke is intravascular lymphoma, in which random skin biopsy can be helpful for antemortem diagnosis.

  15. Recent Improvement of Medical Optical Fibre Pressure and Temperature Sensors

    Directory of Open Access Journals (Sweden)

    Sven Poeggel

    2015-07-01

    Full Text Available This investigation describes a detailed analysis of the fabrication and testing of optical fibre pressure and temperature sensors (OFPTS. The optical sensor of this research is based on an extrinsic Fabry–Perot interferometer (EFPI with integrated fibre Bragg grating (FBG for simultaneous pressure and temperature measurements. The sensor is fabricated exclusively in glass and with a small diameter of 0.2 mm, making it suitable for volume-restricted bio-medical applications. Diaphragm shrinking techniques based on polishing, hydrofluoric (HF acid and femtosecond (FS laser micro-machining are described and analysed. The presented sensors were examined carefully and demonstrated a pressure sensitivity in the range of \\(s_p\\ = 2–10 \\(\\frac{\\text{nm}}{\\text{kPa}}\\ and a resolution of better than \\(\\Delta P\\ = 10 Pa protect (0.1 cm H\\(_2\\O. A static pressure test in 38 cmH\\(_2\\O shows no drift of the sensor in a six-day period. Additionally, a dynamic pressure analysis demonstrated that the OFPTS never exceeded a drift of more than 130 Pa (1.3 cm H\\(_2\\O in a 12-h measurement, carried out in a cardiovascular simulator. The temperature sensitivity is given by \\(k=10.7\\ \\(\\frac{\\text{pm}}{\\text{K}}\\, which results in a temperature resolution of better than \\(\\Delta T\\ = 0.1 K. Since the temperature sensing element is placed close to the pressure sensing element, the pressure sensor is insensitive to temperature changes.

  16. Improved optical enhancement in binary plasmonic gratings with nanogap spacing

    Science.gov (United States)

    Darweesh, Ahmad A.; Bauman, Stephen J.; Brawley, Zachary T.; Herzog, Joseph B.

    2016-09-01

    This work thoroughly investigates binary nanowire gratings with nanogap spacing. A binary plasmonic grating is a periodic nanostructure for which each period has two different widths. The study has determined that plasmonic gratings with two different widths in each period give rise to optical enhancement that is 2.1 times stronger than that of standard plasmonic grating structures. A map of varying width ratios has been created to illustrate the key geometric characteristic for enhancement optimization. The structure under investigation was a gold structure with a constant height of 15 nm and a nanogap of 5 nm. The period size of the structure depends on the two nanowire widths in each grating period. The optical enhancement (E/E0)2 of the geometry was investigated using a finite element method (FEM) simulation for various wavelengths. The results show a strong correlation between the plasmon wavelength and the periodicity of the gratings. Additionally, the plasmonic charge distributions have been calculated for various periods and geometries. Various resonant modes exist for the charge distribution, significantly affecting the enhancement depending on the nanowire widths.

  17. Improved fiber-optic chemical sensor for penicillin

    Energy Technology Data Exchange (ETDEWEB)

    Healy, B.G.; Walt, D.R. [Tufts Univ., Medford, MA (United States)

    1995-12-15

    An optical penicillin biosensor is described, based on the enzyme penicillinase. The sensor is fabricated by selective photodeposition of analyte-sensitive polymer matrices on optical imaging fibers. The penicillin-sensitive matrices are fabricated by immobilizing the enzyme as micrometer-sized particles in a polymer hydrogel with a covalently bound pH indicator. An array of penicillin-sensitive and pH-sensitive matrices are fabricated on the same fiber. This array allows for the simultaneous, independent measurement of pH and penicillin. Independent measurement of the two analytes allows penicillin to be quantitated in the presence of a concurrent pH change. An analysis was conducted of enzyme kinetic parameters in order to model the penicillin response of the sensor at all pH values. This analysis accounts for the varying activity of the immobilized penicillinase at different pH values. The sensor detects penicillin in the range 0.25-10.0 mM in the pH range 6.2-7.5. The sensor was used to quantify penicillin concentration produced during a Penicillium chrysogenum fermentation. 27 refs., 7 figs., 1 tab.

  18. Nonlinear optical microscopy improvement by focal-point axial modulation

    Science.gov (United States)

    Dashtabi, Mahdi Mozdoor; Massudi, Reza

    2016-05-01

    Among the most important challenges of microscopy-even more important than the resolution enhancement, especially in biological and neuroscience applications-is noninvasive and label-free imaging deeper into live scattering samples. However, the fundamental limitation on imaging depth is the signal-to-background ratio in scattering biological tissues. Here, using a vibrating microscope objective in conjunction with a lock-in amplifier, we demonstrate the background cancellation in imaging the samples surrounded by turbid and scattering media, which leads to more clear images deeper into the samples. Furthermore, this technique offers the localization and resolution enhancement as well as resolves ambiguities in signal interpretation, using a single-color laser. This technique is applicable to most nonlinear as well as some linear point-scanning optical microscopies.

  19. Improved water quality retrieval by identifying optically unique water classes

    Science.gov (United States)

    Nazeer, Majid; Nichol, Janet E.

    2016-10-01

    Accurate remote sensing retrieval of water quality parameters in complex coastal environments is challenging due to variability of the coastal environment. For example, in the coastal waters of Hong Kong water quality varies from east to west. The currently existing water zones, defined by the Hong Kong Environmental Protection Department (EPD) are based on ease of access to sampling locations rather than on water quality alone. In this study an archive of fifty-seven Landsat Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+) and HJ-1 A/B Charged Couple Device (CCD) images over a 13-year period (January 2000-December 2012) was used to define optically distinct water classes by Fuzzy c-Means (FCM) clustering. The clustering was applied by combining the Surface Reflectance (SR) derived from the first four bands of Landsat and HJ-1 scenes with 240 insitu samples of Chlorophyll-a (Chl-a) and Suspended Solid (SS) concentrations collected within 2 h of image acquisition. The FCM clustering suggested the existence of five optically different water classes in the region. The significance of the defined water classes was tested in terms of the water SR behaviour in each band. The SR for Classes 1 and 2 in bands 1-3 was lower than in other classes, and band 4 showed the lowest reflectance, indicating that these classes represent a clearer type of water. Class 3 showed intermediate reflectance in all bands, while Classes 4 and 5 showed overall higher reflectance indicating high sediment contribution from the Pearl River Delta. Application of water quality retrievals within individual classes showed much greater confidence with Root Mean Square Error (RMSE) of 1.32 μg/l (1.21 mg/l) for Chl-a (SS) concentrations, compared with 5.97 μg/l (2.98 mg/l) when applied to the whole spectrum of different water types across the region.

  20. Intravascular brachytherapy for peripheral vascular disease

    Directory of Open Access Journals (Sweden)

    Hagen, Anja

    2008-09-01

    Full Text Available Scientific background: Percutaneous transluminal angioplasties (PTA through balloon dilatation with or without stenting, i.e. vessel expansion through balloons with or without of implantation of small tubes, called stents, are used in the treatment of peripheral artery occlusive disease (PAOD. The intravascular vessel irradiation, called intravascular brachytherapy, promises a reduction in the rate of repeated stenosis (rate of restenosis after PTA. Research questions: The evaluation addresses questions on medical efficacy, cost-effectiveness as well as ethic, social and legal implications in the use of brachytherapy in PAOD patients. Methods: A systematic literature search was conducted in August 2007 in the most important medical electronic databases for publications beginning from 2002. The medical evaluation included randomized controlled trials (RCT. The information synthesis was performed using meta-analysis. Health economic modeling was performed with clinical assumptions derived from the meta-analysis and economical assumptions derived from the German Diagnosis Related Groups (G-DRG-2007. Results: Medical evaluation: Twelve publications about seven RCT on brachytherapy vs. no brachytherapy were included in the medical evaluation. Two RCT showed a significant reduction in the rate of restenosis at six and/or twelve months for brachytherapy vs. no brachytherapy after successful balloon dilatation, the relative risk in the meta-analysis was 0.62 (95% CI: 0.46 to 0.84. At five years, time to recurrence of restenosis was significantly delayed after brachytherapy. One RCT showed a significant reduction in the rate of restenosis at six months for brachytherapy vs. no brachytherapy after PTA with optional stenting, the relative risk in the meta-analysis was 0.76 (95% CI: 0.61 to 0.95. One RCT observed a significantly higher rate of late thrombotic occlusions after brachytherapy in the subgroup of stented patients. A single RCT for brachytherapy

  1. A twenty-eight channel coil array for improved optic nerve imaging

    Science.gov (United States)

    Merrill, Robb Phillip

    The purpose of this work was to design and construct a radio-frequency coil optimized for imaging the Optic Nerve (ON) on a Siemens 3T magnetic resonance imaging (MRI) scanner. The specific goals were to optimize signal sensitivity from the orbit to the optic chiasm and improve SNR over designs currently in use. The constructed coil features two fiberglass formers that can slide over each other to accommodate any arbitrary head size, while maintaining close coupling near the eyes and around the head in general. This design eliminates the air void regions that occur between the coil elements and the forehead when smaller heads are imaged in one-piece, nonadjustable coil formers. The 28 coil elements were placed using a soccer-ball pattern layout to maximize head coverage. rSNR profiles from phantom imaging studies show that the ON coil provides approximately 55% greater rSNR at the region of the optic chiasm and approximately 400% near the orbits compared to the 12-channel commercial coil. The improved rSNR in the optic nerve region allows performance of high resolution DTI, which provides a qualitative measurement for evaluating optic neuritis. Images from volunteer and patient studies with the ON coil reveal plaques that correspond well with the patient disease history of chronic bilateral optic neuritis. Correspondence of image findings with patient disease histories demonstrates that optic neuritis can be visualized and detected in patients using 3T MRI with advanced imaging coils, providing improved patient care.

  2. New improvements for Brillouin optical time-domain reflectometry

    Science.gov (United States)

    Le Floch, Sébastien; Sauser, Florian

    2017-04-01

    This paper presents new techniques designed to improve the performances of a BOTDR. The first one introduces a second pump to the sensor, thus doubling the Brillouin signal on the receiver. The second one uses image processing with a two-dimensional Gaussian filter whose parameters are defined. The last technique explores the possibilities offered by colour codes. The benefits of each, in terms of signal-to-noise ratio, is presented by comparing measurements over a distance range of 50km with a spatial resolution of 5m. These techniques can easily be combined and the global improvement is estimated at 10dB, compared to conventional sensors.

  3. 76 FR 77834 - Scientific Information Request on Intravascular Diagnostic and Imaging Medical Devices

    Science.gov (United States)

    2011-12-14

    ... Intravascular Diagnostic and Imaging Medical Devices AGENCY: Agency for Healthcare Research and Quality (AHRQ... intravascular diagnostic and imaging medical devices, including: Fractional Flow Reserve (FFR), Coronary Flow... Resonance Imaging (MRI), Elastrography, and Thermography. Scientific information is being solicited to...

  4. Optical coherence tomography: Monte Carlo simulation and improvement by optical amplification

    DEFF Research Database (Denmark)

    Tycho, Andreas

    2002-01-01

    An advanced novel Monte Carlo simulation model of the detection process of an optical coherence tomography (OCT) system is presented. For the first time it is shown analytically that the applicability of the incoherent Monte Carlo approach to model the heterodyne detection process of an OCT system...... model of the OCT signal. The OCT signal from a scattering medium are obtained for several beam and sample geometries using the new Monte Carlo model, and when comparing to results of an analytical model based on the extended Huygens-Fresnel principle excellent agreement is obtained. With the greater...... flexibility of Monte Carlo simulations, this new model is demonstrated to be excellent as a numerical phantom, i.e., as a substitute for otherwise difficult experiments. Finally, a new model of the signal-to-noise ratio (SNR) of an OCT system with optical amplification of the light reflected from the sample...

  5. Network Performance Improvement under Epidemic Failures in Optical Transport Networks

    DEFF Research Database (Denmark)

    Fagertun, Anna Manolova; Ruepp, Sarah Renée

    2013-01-01

    . First we identify the most vulnerable and the most strategic nodes in the network. Then, via extensive simulations we show that strategic placement of resources for improved failure recovery has better performance than randomly assigning lower repair times among the network nodes. Our OPNET simulation...

  6. Intravascular photoacoustic detection of vulnerable plaque based on constituent selected imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jian; Xing Da, E-mail: xingda@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China)

    2011-01-01

    Atherosclerosis, a disease of the large arteries, is the primary cause of heart disease and stroke. Over decades, atherosclerosis is characterized by thickening of the walls of the arteries, only advanced atherosclerotic disease could be observed. Photoacoustic imaging is a hybrid imaging technique that combines the advantages of high spatial resolution of ultrasound with contrast of optical absorption. In this paper, we present an intravascular photoacoustic (IVPA) imaging system to characterize vulnerable plaques by using the optical absorption contrast between different constituents. Epidemiological studies have revealed several important plaque constituents associated with early atherosclerosis, such as macrophage, cholesterol, lipid, calcification, and so on. We chose a section of lipid rich atherosclerosis artery and a section of normal artery as the phantom. Two IVPA images of them are given to show the difference between sick and normal. As a new method of detecting vulnerable plaque, IVPA constituents imaging will provide more details for diagnosis that offer an enticing prospect in early detecting of atherosclerosis.

  7. Improvements of the optical detection setup of COLLAPS

    CERN Document Server

    Sailer, Stefan

    2015-01-01

    In Collinear Laser Spectroscopy of rare isotopes it is crucial to keep the background of the measurements low. Using photomultiplier tubes for those measurements, the dark count rate should be as low as possible and the signal gain high. Therefore, it is important to use the right type of photomultiplier tubes for the purpose of single photon detection with a low signal rate. Thus, I tested several different types of photomultiplier tubes for their dark count rates and noise to signal separation. The results have identified the most suitable type of photomultiplier tubes, but further measuring for verification might be necessary. Therefore, it is very important to keep the photomultiplier tubes shut from light. Exposing the photocathode to light implies life-long damage and increased background for several days. So far, when dismounting one of these photomultiplier tubes from the setup, a big cage around the optical detection setup was covered into black sheets to keep it as dark as possible inside. Still, th...

  8. Tailoring cyanine dark states for improved optically modulated fluorescence recovery.

    Science.gov (United States)

    Mahoney, Daniel P; Owens, Eric A; Fan, Chaoyang; Hsiang, Jung-Cheng; Henary, Maged M; Dickson, Robert M

    2015-04-02

    Cyanine dyes are well-known for their bright fluorescence and utility in biological imaging. However, cyanines also readily photoisomerize to produce nonemissive dark states. Co-illumination with a secondary, red-shifted light source on-resonance with the longer wavelength absorbing dark state reverses the photoisomerization and returns the cyanine dye to the fluorescent manifold, increasing steady-state fluorescence intensity. Modulation of this secondary light source dynamically alters emission intensity, drastically improving detection sensitivity and facilitating fluorescence signals to be recovered from an otherwise overwhelming background. Red and near-IR emitting cyanine derivatives have been synthesized with varying alkyl chain lengths and halogen substituents to alter dual-laser fluorescence enhancement. Photophysical properties and enhancement with dual laser modulation were coupled with density functional calculations to characterize substituent effects on dark state photophysics, potentially improving detection in high background biological environments.

  9. Improved fibre optic acoustic sensors for partial discharge in elastomeric insulations

    Science.gov (United States)

    Rohwetter, Philipp; Lothongkam, Chaiyaporn; Habel, Wolfgang; Heidmann, Gerd; Pepper, Daniel

    2014-05-01

    Partial discharge in elastomeric high voltage insulations is a major reason for device failure. The special challenges of the high voltage environment limit the use of conventional acoustic emission sensors. Fibre-optic sensors can cope with these challenges thanks to their optical sensing principle and the use of all-dielectric materials. In this contribution, improvements to a previously introduced design of ultrasonic fibre-optic acoustic partial discharge sensors for elastomeric insulations are presented. The improved performance of fibre-optic acoustic sensors in detecting AC partial discharge is demonstrated. Furthermore, their ability to detect low-level damage processes in elastomeric insulation under DC dielectric stress is shown to outperform the highly sensitive electrical detection method.

  10. 21 CFR 880.5970 - Percutaneous, implanted, long-term intravascular catheter.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Percutaneous, implanted, long-term intravascular... and Personal Use Therapeutic Devices § 880.5970 Percutaneous, implanted, long-term intravascular catheter. (a) Identification. A percutaneous, implanted, long-term intravascular catheter is a device...

  11. 21 CFR 880.5965 - Subcutaneous, implanted, intravascular infusion port and catheter.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Subcutaneous, implanted, intravascular infusion... Hospital and Personal Use Therapeutic Devices § 880.5965 Subcutaneous, implanted, intravascular infusion port and catheter. (a) Identification. A subcutaneous, implanted, intravascular infusion port...

  12. Current concepts in the management of disseminated intravascular coagulation.

    Science.gov (United States)

    Thachil, Jecko; Toh, Cheng Hock

    2012-04-01

    Disseminated Intravascular Coagulation is a clinicopathological syndrome where widespread intravascular coagulation occurs in response to an inciting process. The pathophysiology for this disorder is complex with an important role for thrombin, the central regulator of the coagulation process. Since the clinical spectrum of DIC is variable due to its dynamic nature, the laboratory diagnosis should ideally be not based on a single marker or an isolated set of results. The treatment should primary focus on the management of the underlying triggering condition with blood products used as resuscitative measures. Newer therapeutic modalities have been recently tried with success although the management of DIC still remains a major challenge.

  13. The Present Situation on Disseminated Intravascular. Coagulation Studies

    Institute of Scientific and Technical Information of China (English)

    刘泽霖

    2001-01-01

    @@ DIC is not a clinical entity in itself. Instead, it always occurs secondary to a broad spectrum of various diseases. DIC may be defined as an acquired syndrome characterized by the activation of intravascular coagulation up to intravascular fibrin formation. Although the trigger for the activation of the coagulation system may vary depending on the underlying condition, it is usually mediated by several cytokines. Thrombin generation proceeds via the (extrinsic) tissue factor/factor Ⅶ a route and simultaneous depression of inhibitory mechanisms, such as the protein C and protein S system. In addition, impaired fibrin degradation, dur to high circulating levels of PAI-1, contributes to enhanced introvascular fibrin deposition.

  14. Oblong-Shaped-Focused Transducers for Intravascular Ultrasound Imaging.

    Science.gov (United States)

    Lee, Junsu; Jang, Jihun; Chang, Jin Ho

    2017-03-01

    In intravascular ultrasound (IVUS) imaging, a transducer is inserted into a blood vessel and rotated to obtain image data. For this purpose, the transducer aperture is typically less than 0.5 mm in diameter, which causes natural focusing to occur in the imaging depth ranging from 1 to 5 mm. Due to the small aperture, however, it is not viable to conduct geometric focusing in order to enhance the spatial resolution of IVUS images. Furthermore, this hampers narrowing the slice thickness of a cross-sectional scan plane in the imaging depth, which leads to lowering spatial and contrast resolutions of IVUS images. To solve this problem, we propose an oblong-shaped-focused transducer for IVUS imaging. Unlike the conventional IVUS transducers with either a circular or a square flat aperture, the proposed transducer has an oblong aperture of which long side is positioned along a blood vessel. This unique configuration makes it possible to conduct geometric focusing at a desired depth in the elevation direction. In this study, furthermore, it is demonstrated that a spherically shaped aperture in both lateral and elevation directions also improves lateral resolution, compared to the conventional flat aperture. To ascertain this, the conventional and the proposed IVUS transducers were designed and fabricated to evaluate and to compare their imaging performances through wire phantom and tissue-mimicking phantom experiments. For the proposed 50-MHz IVUS transducer, a PZT piece of 0.5 × 1.0 mm(2) was spherically shaped for elevation focus at 3 mm by using the conventional press-focusing technique whereas the conventional one has a flat aperture of 0.5 × 0.5 mm(2). The experimental results demonstrated that the proposed IVUS transducer is capable of improving spatial and contrast resolutions of IVUS images.

  15. Improving Acousto-Optical Interaction by Mechanical Resonators on a Surface

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    The finite element method is employed to model surface acoustic waves generated by high aspect ratio electrodes and their interaction with an optical wave in a waveguide. With a periodic model it is first shown that these electrodes act as a mechanical resonator, which introduces several confined...... types of surface acoustic waves compared to using a conventional interdigital transducer with thin electrodes. Thus, this indicates a way to improve acousto-optical interaction for integrated modulators....

  16. Improved optical packet switching structure with recirculation buffer and feedback tunable wavelength converter

    Institute of Scientific and Technical Information of China (English)

    Cheng Wu; Shilin Xiao

    2009-01-01

    The performance of an optical switching network is mainly determined by its core node structure.An improved optical packet switching(OPS)node structure based on recirculation optical fiber delay line(FDL)and feedback tunable wavelength converter(TWC),and a specific scheduling algorithm for the node structure are presented.This switching structure supports both point-to-point and point-to-multi-points broadcasting transmission with superior capacity expansion performance.Its superiority in packet loss probability is proved by simulation.

  17. Acute kidney injury and disseminated intravascular coagulation due to mercuric chloride poisoning

    Science.gov (United States)

    Dhanapriya, J.; Gopalakrishnan, N.; Arun, V.; Dineshkumar, T.; Sakthirajan, R.; Balasubramaniyan, T.; Haris, M.

    2016-01-01

    Mercury is a toxic heavy metal and occurs in organic and inorganic forms. Inorganic mercury includes elemental mercury and mercury salts. Mercury salts are usually white powder or crystals, and widely used in indigenous medicines and folk remedies in Asia. Inorganic mercury poisoning causes acute kidney injury (AKI) and gastrointestinal manifestations and can be life-threatening. We describe a case with unknown substance poisoning who developed AKI and disseminated intravascular coagulation (DIC). Renal biopsy showed acute tubular necrosis. Later, the consumed substance was proven to be mercuric chloride. His renal failure improved over time, and his creatinine normalized after 2 months. PMID:27194836

  18. Approach to improve beam quality of inter-satellite optical communication system based on diffractive optical elements.

    Science.gov (United States)

    Tan, Liying; Yu, Jianjie; Ma, Jing; Yang, Yuqiang; Li, Mi; Jiang, Yijun; Liu, Jianfeng; Han, Qiqi

    2009-04-13

    For inter-satellite optical communication transmitter with reflective telescope of two-mirrors on axis, a large mount of the transmitted energy will be blocked by central obscuration of the secondary mirror. In this paper, a novel scheme based on diffractive optical element (DOE) is introduced to avoid it. This scheme includes one diffractive beam shaper and another diffractive phase corrector, which can diffract the obscured part of transmitted beam into the domain unobscured by the secondary mirror. The proposed approach is firstly researched with a fixed obscuration ratio of 1/4. Numerical simulation shows that the emission efficiency of new figuration is 99.99%; the beam divergence from the novel inter-satellite optical communication transmitter is unchanged; and the peak intensity of receiver plane is increased about 31% compared with the typical configuration. Then the intensy patterns of receiver plane are analyzed with various obscuration ratio, the corresponding numerical modelling reveals that the intensity patterns with various obscuration ratio are nearly identical, but the amplify of relative peak intensity is getting down with the growth of obscuration ratio. This work can improve the beam quality of inter-satellite optical communication system without affecting any other functionality.

  19. An improved image reconstruction method for optical intensity correlation Imaging

    Science.gov (United States)

    Gao, Xin; Feng, Lingjie; Li, Xiyu

    2016-12-01

    The intensity correlation imaging method is a novel kind of interference imaging and it has favorable prospects in deep space recognition. However, restricted by the low detecting signal-to-noise ratio (SNR), it's usually very difficult to obtain high-quality image of deep space object like high-Earth-orbit (HEO) satellite with existing phase retrieval methods. In this paper, based on the priori intensity statistical distribution model of the object and characteristics of measurement noise distribution, an improved method of Prior Information Optimization (PIO) is proposed to reduce the ambiguous images and accelerate the phase retrieval procedure thus realizing fine image reconstruction. As the simulations and experiments show, compared to previous methods, our method could acquire higher-resolution images with less error in low SNR condition.

  20. A Broadband Polyvinylidene Difluoride-Based Hydrophone with Integrated Readout Circuit for Intravascular Photoacoustic Imaging.

    Science.gov (United States)

    Daeichin, Verya; Chen, Chao; Ding, Qing; Wu, Min; Beurskens, Robert; Springeling, Geert; Noothout, Emile; Verweij, Martin D; van Dongen, Koen W A; Bosch, Johan G; van der Steen, Antonius F W; de Jong, Nico; Pertijs, Michiel; van Soest, Gijs

    2016-05-01

    Intravascular photoacoustic (IVPA) imaging can visualize the coronary atherosclerotic plaque composition on the basis of the optical absorption contrast. Most of the photoacoustic (PA) energy of human coronary plaque lipids was found to lie in the frequency band between 2 and 15 MHz requiring a very broadband transducer, especially if a combination with intravascular ultrasound is desired. We have developed a broadband polyvinylidene difluoride (PVDF) transducer (0.6 × 0.6 mm, 52 μm thick) with integrated electronics to match the low capacitance of such a small polyvinylidene difluoride element (<5 pF/mm(2)) with the high capacitive load of the long cable (∼100 pF/m). The new readout circuit provides an output voltage with a sensitivity of about 3.8 μV/Pa at 2.25 MHz. Its response is flat within 10 dB in the range 2 to 15 MHz. The root mean square (rms) output noise level is 259 μV over the entire bandwidth (1-20 MHz), resulting in a minimum detectable pressure of 30 Pa at 2.25 MHz.

  1. Lipid detection by intravascular photoacoustic imaging with flexible catheter at 20 fps (Conference Presentation)

    Science.gov (United States)

    Wu, Min; Daeichin, Verya; Springeling, Geert; van der Steen, Antonius F. W.; van Soest, Gijs

    2016-02-01

    Intravascular Photoacoustic (IVPA) imaging is a promising new technology to assess lipid content of coronary atherosclerotic plaque, an important determinant of the risk associated with the plaque triggering a heart attack. Clinical translation of IVPA imaging requires real-time image acquisition, which has been a technological challenge. In this work, we demonstrate a high-speed, dual-wavelength IVPA imaging system at 1.7 µm wavelength, operating with a flexible catheter of 1.2 mm outer diameter (including outer sheath). The catheter was custom designed and fabricated, and used a 40 MHz transducer for intravascular ultrasound (IVUS) and IVPA imaging. The optical excitation is provided by a dual OPO system, pumped by CW diode-pumped Q-switched Nd:YAG lasers, with a repetition rate of 5 kHz. Each OPO can be tuned to a custom wavelength between 1690 and 1750 nm; two wavelengths only are needed to discriminate between plaque lipids and adipose tissue. The pulse energy is about 80 µJ. We tested the imaging performance of the presented system in a polyvinyl-alcohol (PVA) vessel mimicking phantom and human coronary arteries ex vivo. IVPA identified lipid deposits inside atherosclerotic plaque, while IVUS showed tissue structure. We demonstrated IVPA imaging at a speed of 20 frames per second, with 250 A-scans per frame. This is significantly faster than previous IVPA imaging systems, and will enable the translation of IVPA imaging into clinical practice.

  2. Experimental results for improving the matrix condition using a hybrid optical system.

    Science.gov (United States)

    Klapp, Iftach; Mendlovic, David

    2012-03-01

    We present preliminary experimental results for implementing the "blurred trajectories" method on three parallel optics (PO) systems. The "main" system and "auxiliary" optics were simple laboratory graded lenses attached to an iris diaphragm. When applying the blurred trajectories method we first show an improvement in the matrix condition, as the matrix condition number decreased in a range of factors of 3 to 418 relative to the main system. Following that, image restoration by weak regularization was performed so that the system matrix condition dominated the restoration process. It was shown that the restoration results of the PO are better than those of the main system and the auxiliary optics separately. In addition, the quality of the restoration follows the system's matrix condition. The improvement in the matrix condition achieved by the PO system improved the immunity to detection noise. Finally, a comparison to Wiener filtering restoration shows that it is also generally inferior to the proposed method.

  3. Improving breast cancer diagnosis by reducing chest wall effect in diffuse optical tomography

    Science.gov (United States)

    Zhou, Feifei; Mostafa, Atahar; Zhu, Quing

    2017-03-01

    We have developed the ultrasound (US)-guided diffuse optical tomography technique to assist US diagnosis of breast cancer and to predict neoadjuvant chemotherapy response of patients with breast cancer. The technique was implemented using a hand-held hybrid probe consisting of a coregistered US transducer and optical source and detector fibers which couple the light illumination from laser diodes and photon detection to the photomultiplier tube detectors. With the US guidance, diffused light measurements were made at the breast lesion site and the normal contralateral reference site which was used to estimate the background tissue optical properties for imaging reconstruction. However, background optical properties were affected by the chest wall underneath the breast tissue. We have analyzed data from 297 female patients, and results have shown statistically significant correlation between the fitted optical properties (μa and μs‧) and the chest wall depth. After subtracting the background μa at each wavelength, the difference of computed total hemoglobin (tHb) between malignant and benign lesion groups has improved. For early stage malignant lesions, the area-under-the-receiver operator characteristic curve (AUC) has improved from 88.5% to 91.5%. For all malignant lesions, the AUC has improved from 85.3% to 88.1%. Statistical test has revealed the significant difference of the AUC improvements after subtracting background tHb values.

  4. Improving the All-Optical Response of SOAs Using a Modulated Holding Signal

    DEFF Research Database (Denmark)

    Bischoff, Svend; Nielsen, Mads Lønstrup; Mørk, Jesper

    2004-01-01

    A method for increasing the all-optical modulation bandwidth of semiconductor optical amplifiers (SOAs) by use of a cross-gain-modulated (XGM) holding signal is suggested and analyzed. The bandwidth improvement is numerically demonstrated by studying wavelength conversion in an SOA-based Mach......-Zehnder interferometer (MZI) at 160 and 40 Gb/s. The new scheme is predicted to improve the extinction ratio and the minimum mark output power, as well as to reduce the amplitude jitter of the wavelength converted signal....

  5. Disseminated intravascular coagulation in malaria: A case report

    Directory of Open Access Journals (Sweden)

    Laltanpuii Sailo

    2014-01-01

    Full Text Available Disseminated intravascular coagulation (DIC is seen in <5% of patients with severe Plasmodium falciparum malaria and is more common in cerebral malaria. Here, we report the diagnosis and management of a case of severe P. falciparum malaria with DIC.

  6. Mechanical scanning in intravascular ultrasound imaging: Artifacts and driving mechanisms

    NARCIS (Netherlands)

    H. ten Hoff (H.); E.J. Gussenhoven (Elma); C.M. Korbijn (Carin); F. Mastik (Frits); C.T. Lancée (Charles); N. Bom (Klaas)

    1995-01-01

    textabstractObjective: Currently, intravascular ultrasound (US) imaging catheters are developed and produced to provide a complementary diagnostic method in the treatment of blood vessel obstructive disease. Typical catheter dimensions are a diameter of 1–2.5 mm and a length of 1–1.5 m. A real-time

  7. 21 CFR 880.5440 - Intravascular administration set.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intravascular administration set. 880.5440 Section 880.5440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...) Classification. Class II (special controls). The special control for pharmacy compounding systems within this...

  8. Brachytherapy optimal planning with application to intravascular radiation therapy

    DEFF Research Database (Denmark)

    Sadegh, Payman; Mourtada, Firas A.; Taylor, Russell H.;

    1999-01-01

    . Dose rate calculations are based on the sosimetry formulation of the American Association of Physicists in Medicine, Task Group 43. We apply the technique to optimal planning for intravascular brachytherapy of intimal hyperplasia using ultrasound data and 192Ir seeds. The planning includes...

  9. Detection of vascular morphology by high frequency intravascular ultrasonic imaging

    NARCIS (Netherlands)

    W.J. Gussenhoven (Wilhelmina Johanna); G.S. Madretsma (Guno); H. Pieterman; S.H.K. The (Salem); L. Wenguang; F.C. van Egmond (F.); N. Bom (Klaas)

    1991-01-01

    textabstractThis study was designed to validate the potential clinical utility of intravascular ultrasonic imaging in vitro and in vivo. In vitro studies were performed to assess the accuracy of dimensional and morphological information. In vitro images of human vessels (n = 75) demonstrated that le

  10. Disseminated intravascular coagulopathy in dengue:a brief review

    Institute of Scientific and Technical Information of China (English)

    Viroj Wiwanitkit

    2009-01-01

    Dengue infection is an arboviral infection with a very high prevalence in tropical Southeast Asia.This infection presents as a clinical illness comprising of very high fever with several hematologic aberrations.In this article, the author briefly reviewed the report on disseminated intravascular coagulopathy (DIC),a severe complica-tion,in dengue.

  11. Detection of vascular morphology by high frequency intravascular ultrasonic imaging

    NARCIS (Netherlands)

    W.J. Gussenhoven (Wilhelmina Johanna); G.S. Madretsma (Guno); H. Pieterman; S.H.K. The (Salem); L. Wenguang; F.C. van Egmond (F.); N. Bom (Klaas)

    1991-01-01

    textabstractThis study was designed to validate the potential clinical utility of intravascular ultrasonic imaging in vitro and in vivo. In vitro studies were performed to assess the accuracy of dimensional and morphological information. In vitro images of human vessels (n = 75) demonstrated that le

  12. A Prognostic Dilemma of Basal Cell Carcinoma with Intravascular Invasion

    Science.gov (United States)

    Niumsawatt, Vachara; Castley, Andrew

    2016-01-01

    Summary: Basal cell carcinoma is the most common malignancy; however, it very rarely metastasizes. Despite the low mortality caused by this cancer, once it spreads, it has dim prognosis. We report a case of basal cell carcinoma with rare intravascular invasion and review the literature for risk factors and management of metastasis.

  13. Analysis and correction of linear optics errors, and operational improvements in the Indus-2 storage ring

    Science.gov (United States)

    Husain, Riyasat; Ghodke, A. D.

    2017-08-01

    Estimation and correction of the optics errors in an operational storage ring is always vital to achieve the design performance. To achieve this task, the most suitable and widely used technique, called linear optics from closed orbit (LOCO) is used in almost all storage ring based synchrotron radiation sources. In this technique, based on the response matrix fit, errors in the quadrupole strengths, beam position monitor (BPM) gains, orbit corrector calibration factors etc. can be obtained. For correction of the optics, suitable changes in the quadrupole strengths can be applied through the driving currents of the quadrupole power supplies to achieve the desired optics. The LOCO code has been used at the Indus-2 storage ring for the first time. The estimation of linear beam optics errors and their correction to minimize the distortion of linear beam dynamical parameters by using the installed number of quadrupole power supplies is discussed. After the optics correction, the performance of the storage ring is improved in terms of better beam injection/accumulation, reduced beam loss during energy ramping, and improvement in beam lifetime. It is also useful in controlling the leakage in the orbit bump required for machine studies or for commissioning of new beamlines.

  14. Improved ice particle optical property simulations in the ultraviolet to far-infrared regime

    Science.gov (United States)

    Bi, Lei; Yang, Ping

    2017-03-01

    To derive the bulk radiative properties of ice clouds, aircraft contrails and snow grains, which are fundamental to atmospheric radiative transfer calculations in downstream applications, it is necessary to accurately simulate the scattering of light by individual ice particles. An ice particle optical property database reported in 2013 (hereafter, TAMUice2013) is updated (hereafter, TAMUice2016) to incorporate recent advances in computation of the optical properties of nonspherical particles. Specifically, we employ the invariant imbedding T-matrix (II-TM) method to compute the optical properties of particles with small to moderate size parameters. Both versions use the Improved Geometric Optics Method (IGOM) to compute the optical properties of large ice crystals, but TAMUice2016 improves the treatment of inhomogeneous waves inside the scattering particles in the case where ice is absorptive such as at infrared wavelengths. To bridge the gap between the extinction efficiencies computed from the II-TM and the IGOM, TAMUice2016 includes spectrally dependent higher order terms of the edge effect in addition to the first order counterpart considered in TAMUice2013. Furthermore, the differences between TAMUice2013 and TAMUice2016 are quantified with respect to the computation of the bulk optical properties of ice clouds.

  15. The electronic image stabilization technology research based on improved optical-flow motion vector estimation

    Science.gov (United States)

    Wang, Chao; Ji, Ming; Zhang, Ying; Jiang, Wentao; Lu, Xiaoyan; Wang, Jiaoying; Yang, Heng

    2016-01-01

    The electronic image stabilization technology based on improved optical-flow motion vector estimation technique can effectively improve the non normal shift, such as jitter, rotation and so on. Firstly, the ORB features are extracted from the image, a set of regions are built on these features; Secondly, the optical-flow vector is computed in the feature regions, in order to reduce the computational complexity, the multi resolution strategy of Pyramid is used to calculate the motion vector of the frame; Finally, qualitative and quantitative analysis of the effect of the algorithm is carried out. The results show that the proposed algorithm has better stability compared with image stabilization based on the traditional optical-flow motion vector estimation method.

  16. Improved analytical model for the field of index-guiding microstructured optical fibers

    Science.gov (United States)

    Sharma, Dinesh Kumar; Sharma, Anurag

    2016-05-01

    We present an improved version of our earlier developed analytical field model for the fundamental mode of index-guiding microstructured optical fibers (MOFs), to obtain better accuracy in the simulated results. Using this improved field model, we have studied the splice losses between an MOF and a traditional step-index single-mode fiber (SMF). Comparisons with available experimental and numerical simulation results have also been included.

  17. Atomic layer deposition enhanced grafting of phosphorylcholine on stainless steel for intravascular stents.

    Science.gov (United States)

    Zhong, Qi; Yan, Jin; Qian, Xu; Zhang, Tao; Zhang, Zhuo; Li, Aidong

    2014-09-01

    In-stent restenosis (ISR) and re-endothelialization delay are two major issues of intravascular stent in terms of clinical safety and effects. Construction of mimetic cell membrane surface on stents using phosphorylcholine have been regarded as one of the most powerful strategies to resolve these two issues and improve the performance of stents. In this study, atomic layer deposition (ALD) technology, which is widely used in semiconductor industry, was utilized to fabricate ultra-thin layer (10nm) of alumina (Al2O3) on 316L stainless steel (SS), then the alumina covered surface was modified with 3-aminopropyltriethoxysilane (APS) and 2-methacryloyloxyethyl phosphorylcholine (MPC) sequentially in order to produce phosphorylcholine mimetic cell membrane surface. The pristine and modified surfaces were characterized using X-ray photoelectron spectroscopy, atomic force microscope and water contact angle measurement. Furthermore, the abilities of protein adsorption, platelet adhesion and cell proliferation on the surfaces were investigated. It was found that alumina layer can significantly enhance the surface grafting of APS and MPC on SS; and in turn efficiently inhibit protein adsorption and platelet adhesion, and promote the attachment and proliferation of human umbilical vein endothelial cells (HUVEC) on the surfaces. In association with the fact that the deposition of alumina layer is also beneficial to the improvement of adhesion and integrity of drug-carrying polymer coating on drug eluting stents, we expect that ALD technology can largely assist in the modifications on inert metallic surfaces and benefit implantable medical devices, especially intravascular stents.

  18. Assimilation of remotely-sensed optical properties to improve marine biogeochemistry modelling

    Science.gov (United States)

    Ciavatta, Stefano; Torres, Ricardo; Martinez-Vicente, Victor; Smyth, Timothy; Dall'Olmo, Giorgio; Polimene, Luca; Allen, J. Icarus

    2014-09-01

    In this paper we evaluate whether the assimilation of remotely-sensed optical data into a marine ecosystem model improves the simulation of biogeochemistry in a shelf sea. A localized Ensemble Kalman filter was used to assimilate weekly diffuse light attenuation coefficient data, Kd(443) from SeaWiFs, into an ecosystem model of the western English Channel. The spatial distributions of (unassimilated) surface chlorophyll from satellite, and a multivariate time series of eighteen biogeochemical and optical variables measured in situ at one long-term monitoring site were used to evaluate the system performance for the year 2006. Assimilation reduced the root mean square error and improved the correlation with the assimilated Kd(443) observations, for both the analysis and, to a lesser extent, the forecast estimates, when compared to the reference model simulation. Improvements in the simulation of (unassimilated) ocean colour chlorophyll were less evident, and in some parts of the Channel the simulation of this data deteriorated. The estimation errors for the (unassimilated) in situ data were reduced for most variables with some exceptions, e.g. dissolved nitrogen. Importantly, the assimilation adjusted the balance of ecosystem processes by shifting the simulated food web towards the microbial loop, thus improving the estimation of some properties, e.g. total particulate carbon. Assimilation of Kd(443) outperformed a comparative chlorophyll assimilation experiment, in both the estimation of ocean colour data and in the simulation of independent in situ data. These results are related to relatively low error in Kd(443) data, and because it is a bulk optical property of marine ecosystems. Assimilation of remotely-sensed optical properties is a promising approach to improve the simulation of biogeochemical and optical variables that are relevant for ecosystem functioning and climate change studies.

  19. Adaptive optics in spinning disk microscopy: improved contrast and brightness by a simple and fast method.

    Science.gov (United States)

    Fraisier, V; Clouvel, G; Jasaitis, A; Dimitrov, A; Piolot, T; Salamero, J

    2015-09-01

    Multiconfocal microscopy gives a good compromise between fast imaging and reasonable resolution. However, the low intensity of live fluorescent emitters is a major limitation to this technique. Aberrations induced by the optical setup, especially the mismatch of the refractive index and the biological sample itself, distort the point spread function and further reduce the amount of detected photons. Altogether, this leads to impaired image quality, preventing accurate analysis of molecular processes in biological samples and imaging deep in the sample. The amount of detected fluorescence can be improved with adaptive optics. Here, we used a compact adaptive optics module (adaptive optics box for sectioning optical microscopy), which was specifically designed for spinning disk confocal microscopy. The module overcomes undesired anomalies by correcting for most of the aberrations in confocal imaging. Existing aberration detection methods require prior illumination, which bleaches the sample. To avoid multiple exposures of the sample, we established an experimental model describing the depth dependence of major aberrations. This model allows us to correct for those aberrations when performing a z-stack, gradually increasing the amplitude of the correction with depth. It does not require illumination of the sample for aberration detection, thus minimizing photobleaching and phototoxicity. With this model, we improved both signal-to-background ratio and image contrast. Here, we present comparative studies on a variety of biological samples.

  20. Performance improvement of optical fiber coupler with electric heating versus gas heating.

    Science.gov (United States)

    Shuai, Cijun; Gao, Chengde; Nie, Yi; Peng, Shuping

    2010-08-20

    Gas heating has been widely used in the process of fused biconical tapering. However, as the instability and asymmetric flame temperature of gas heating exist, the performance of the optical devices fabricated by this method was affected. To overcome the problems resulting from gas combustion, an electric heater is designed and manufactured using a metal-ceramic (MoSi(2)) as a heating material. Our experimental data show that the fused-taper machine with an electric heater has improved the performance of optical devices by increasing the consistency of the extinction ratio, excess loss, and the splitting ratio over that of the previous gas heating mode. Microcrystallizations and microcracks were observed at the fused region of the polarization-maintaining (PM) fiber coupler and at the taper region with scanning electron microscopy and atomic force microscopy respectively. The distribution of the microcrystallizations and microcracks are nonuniform along the fiber with gas heating, while their distribution is rather uniform with electric heating. These findings show that the novel optical fiber coupler with an electric heater has improved the performance of optical fiber devices by affecting the consistency of the optical parameters and micromorphology of the surface of PM fiber.

  1. Full Aperture CO2 Laser Process to Improve Laser Damage Resistance of Fused Silica Optical Surface

    Directory of Open Access Journals (Sweden)

    Wei Liao

    2014-01-01

    Full Text Available An improved method is presented to scan the full-aperture optical surface rapidly by using galvanometer steering mirrors. In contrast to the previous studies, the scanning velocity is faster by several orders of magnitude. The velocity is chosen to allow little thermodeposition thus providing small and uniform residual stress. An appropriate power density is set to obtain a lower processing temperature. The proper parameters can help to prevent optical surface from fracturing during operation at high laser flux. S-on-1 damage test results show that the damage threshold of scanned area is approximately 40% higher than that of untreated area.

  2. Vision improvement in a Taiwanese (Han Chinese) family with Leber's hereditary optic neuropathy.

    Science.gov (United States)

    Lin, Hong-Zin; Pang, Cheng-Yoong; Chen, Shee-Ping; Tsai, Rong-Kung

    2012-12-01

    In this report, we describe a Taiwanese (Han Chinese) family with Leber's hereditary optic neuropathy. The family carried a mitochondrial DNA mutation (mtDNA m.14484T>C) associated with spontaneous visual improvement. A 15-year-old boy from this family was diagnosed with Leber's hereditary optic neuropathy 6 months after losing his vision. His vision recovered after 8 months of supportive treatment. His mother, older brother, and two sisters also had the same mutation and had previously experienced vision loss. In this family, there was no male predominance.

  3. Improvement on the magneto-optical Kerr effect of cobalt film with a quadrilayer structure

    Institute of Scientific and Technical Information of China (English)

    Zhang Shao-Yin; Tang Shao-Long; Gao Jin-Long; Luo Xiao-Jing; Xia Wen-Bin; Du You-Wei

    2013-01-01

    The magneto-optical Kerr effect of the HfO2/Co/HfO2/Al multilayer structure is investigated in this work,and an obvious cavity enhancement of the Kerr response for the HfO2 semiconductor is found both theoretically and experimentally.Surprisingly,a maximum value of about-3° of the polar Kerr rotation for s-polarized incident light is observed in our experiment.We propose that this improvement on the Kerr effect can be attributed to the multiple reflection and optical interference in the cavity,which can also be proved by simulation using the finite element method.

  4. Improved quality of optical coherence tomography imaging of basal cell carcinomas using speckle reduction

    DEFF Research Database (Denmark)

    Mogensen, Mette; Jørgensen, Thomas Martini; Thrane, Lars

    2010-01-01

    BACKGROUND: Optical coherence tomography (OCT) is a possible imaging method for delineation of non-melanoma skin cancer. Speckle noise is the dominant noise contribution in OCT images; it limits the ability to identify cellular structures especially skin cancer. QUESTIONS ADDRESSED: This report...... suggests a method for improving OCT image quality for skin cancer imaging. EXPERIMENTAL DESIGN: OCT is an optical imaging method analogous to ultrasound. Two basal cell carcinomas (BCC) were imaged using an OCT speckle reduction technique (SR-OCT) based on repeated scanning by altering the distance between...... to a clinically relevant level when imaging BCC lesions....

  5. Forty-Four Pass Fibre Optic Loop for Improving the Sensitivity of Surface Plasmon Resonance Sensors

    CERN Document Server

    Su, Chin B

    2007-01-01

    A forty-four pass fibre optic surface plasmon resonance sensor that enhances detection sensitivity according to the number of passes is demonstrated for the first time. The technique employs a fibre optic recirculation loop that passes the detection spot forty- four times, thus enhancing sensitivity by a factor of forty-four. Presently, the total number of passes is limited by the onset of lasing action of the recirculation loop. This technique offers a significant sensitivity improvement for various types of plasmon resonance sensors that may be used in chemical and biomolecule detections.

  6. Improved Fluorescent Protein Contrast and Discrimination by Optically Controlling Dark State Lifetimes.

    Science.gov (United States)

    Chen, Yen-Cheng; Dickson, Robert M

    2017-02-16

    Modulation and optical control of photoswitchable fluorescent protein (PS-FP) dark state lifetimes drastically improves sensitivity and selectivity in fluorescence imaging. The dark state population of PS-FPs generates an out-of-phase fluorescence component relative to the sinusoidally modulated 488 nm laser excitation. Because this apparent phase advanced emission results from slow recovery to the fluorescent manifold, we hasten recovery and, therefore, modulation frequency by varying coillumination intensity at 405 nm. As 405 nm illumination regenerates the fluorescent ground state more rapidly than via thermal recovery, we experimentally demonstrate that secondary illumination can control PS-FPs dark state lifetime to act as an additional dimension for discriminating spatially and spectrally overlapping emitters. This experimental combination of out of phase imaging after optical modulation (OPIOM) and synchronously amplified fluorescence image recovery (SAFIRe) optically controls the fluorescent protein dark state lifetimes for improved time resolution, with the resulting modulation-based selective signal recovery being quantitatively modeled. The combined experimental results and quantitative numerical simulations further demonstrate the potential of SAFIRe-OPIOM for wide-field biological imaging with improved speed, sensitivity, and optical resolution over other modulation-based fluorescence microscopies.

  7. Improved performance of the laser guide star adaptive optics system at Lick Observatory

    Energy Technology Data Exchange (ETDEWEB)

    An, J R; Avicola, K; Bauman, B J; Brase, J M; Campbell, E W; Carrano, C; Cooke, J B; Freeze, G J; Friedman, H W; Max, C E; Gates, E L; Gavel, D T; Kanz, V K; Kuklo, T C; Macintosh, B A; Newman, M J; Olivier, S S; Pierce, E L; Waltjen, K E; Watson, A

    1999-07-20

    Results of experiments with the laser guide star adaptive optics system on the 3-meter Shane telescope at Lick Observatory have demonstrated a factor of 4 performance improvement over previous results. Stellar images recorded at a wavelength of 2 {micro}m were corrected to over 40% of the theoretical diffraction-limited peak intensity. For the previous two years, this sodium-layer laser guide star system has corrected stellar images at this wavelength to {approx}10% of the theoretical peak intensity limit. After a campaign to improve the beam quality of the laser system, and to improve calibration accuracy and stability of the adaptive optics system using new techniques for phase retrieval and phase-shifting diffraction interferometry, the system performance has been substantially increased. The next step will be to use the Lick system for astronomical science observations, and to demonstrate this level of performance with the new system being installed on the 10-meter Keck II telescope.

  8. Experimental verification of optically optimized CuGaSe2 top cell for improving chalcopyrite tandems*

    Directory of Open Access Journals (Sweden)

    Lux-Steiner M. Ch.

    2010-10-01

    Full Text Available An efficient tandem solar cell requires a top cell which is highly transparent below the energy gap of its absorber. Previously we had reported on a theoretically optimized CuGaSe2 top cell stack based on realistic material properties. It promised a significant increase in optical transparency and, consequently, enhanced CuGaSe2/Cu(In,GaSe2 tandem efficiency. Here we present the first steps taken towards the experimental realization of this optimized tandem. We started with a mechanically stacked device which achieved 8.5% efficiency. Optical measurements of the improved top cells and corresponding photo current densities of the filtered bottom cell are reported. The experimental findings are in agreement with the optical modeling. These data are used to assess the level of tandem performance that could be accomplished in the near future and to discuss the priorities of further research.

  9. Combined use of optical coherence tomography and intravascular ultrasound during percutaneous coronary intervention in patients with coronary artery disease%光学相干断层成像和血管内超声在冠状动脉介入手术中的应用

    Institute of Scientific and Technical Information of China (English)

    侯静波; 孟令波; 景慎鸿; 韩志刚; 于淮; 于波

    2008-01-01

    目的 应用光学相干断层成像(OCT)及血管内超声(IVUS)检测技术评价冠状动脉内粥样硬化斑块的稳定性,并指导支架置入,检测血管对置入支架后即刻和中远期的反应.方法 选择2008年2-7月间的27例患者,进行冠状动脉造影、OCT及IVUS检查,共检查了30支血管,其中8处为药物支架植入术后血管,并对19处病变进行了支架置入.结果 除外支架置入的8例(置入6个月~4年)外,其余22例病变行OCT及IVUS检查,发现稳定性斑块5例,不稳定斑块17例,其中OCT检出内膜小撕裂4例(IVUS未检出,P>0.05),冠状动脉撕裂伴夹层病变5例(IVUS检出1例,P>0.05),血栓形成5例(IVUS检出1例,P>0.05),偏心斑块伴薄纤维帽12例(IVUS检出2例,P<0.01).8例曾经进行支架治疗的患者,造影、OCT和IVUS发现2例再狭窄;OCT显示支架内膜覆盖良好,IVUS小能精确看到内膜;OCT检测出1例患者有支架后瘤样扩张.对17例不稳定性斑块及2例支架再狭窄病例行支架置入术,术后支架膨胀不良发生率26.0%,OCT及IVUS检出率相同;支架贴壁不良发生率63.2%,IVUS榆出率低于OCT(10.5%比63.2%,P<0.01);支架近远端撕裂10.5%,IVUS均不能检出;内膜脱垂发生率52.6%,IVUS检出率低于OCT(10.5%比52.6%,P<0.05).结论 OCT与IVUS相比,在不稳定性斑块检测准确度方面明显优于IVUS,更能精确指导冠状动脉支架置人.IVUS在操作简便性及反映斑块负荷方面要优于OCT.%Objective To evaluate the value of combined optical coherence tomography (OCT) and intravascular ultrasound (IVUS) examinations in detecting coronary artery plaque during percutaneous transluminal coronary intervention (PCI).Methods CICT and IVUS examinations were performed on 30 diseased coronary vessels from 27 patients underwent PCI from Feb.2008 to Jul.2008.Results Seventeen vulnerable plaques (4 intima tearing which were not detected by IVUS),5 plaque rupture (1 out of 5 was detected by IVUS),5 thrombus

  10. Disseminated intravascular coagulation in term and preterm neonates.

    Science.gov (United States)

    Veldman, Alex; Fischer, Doris; Nold, Marcel F; Wong, Flora Y

    2010-06-01

    Among critically ill patients, the risk of developing disseminated intravascular coagulation (DIC) is probably highest in neonates. Low plasma reserves in pro- and anticoagulant coagulation factors, intravascular volume contraction after birth, and a high incidence of hypoxia and sepsis in critically ill newborns rapidly lead to a decompensation of the coagulation system in this population. Global coagulation tests and single-factor plasma levels have to be interpreted in the context of age-corrected normal ranges. Platelet consumption and reduced protein C plasma levels have diagnostic value; the latter also has prognostic potential in neonates with DIC and sepsis. Therapeutic success relies heavily on reversal of the underlying condition. Some coagulation-specific therapies have been explored in small studies and case series with varying success and sometimes conflicting results. Therefore, larger controlled trials in this common and serious condition are urgently needed.

  11. Disseminated intravascular coagulation: a review for the internist.

    Science.gov (United States)

    Levi, Marcel; van der Poll, Tom

    2013-02-01

    Disseminated intravascular coagulation (DIC) is a syndrome characterized by systemic intravascular activation of coagulation, leading to widespread deposition of fibrin in the circulation. Recent knowledge on important pathogenetic mechanisms that may lead to DIC has resulted in novel preventive and therapeutic approaches to patients with DIC. The diagnosis of DIC can be made by sensitive laboratory tests; however, most of these tests are not readily available in a clinical setting. A reliable diagnosis can also be made on the basis of a small series of laboratory tests that can be combined in a scoring algorithm. The cornerstone of the management of DIC is the specific and vigorous treatment of the underlying disorder. Strategies aimed at the inhibition of coagulation activation may theoretically be justified and have been found beneficial in experimental and clinical studies. These strategies comprise inhibition of tissue factor-mediated activation of coagulation or restoration of physiological anticoagulant pathways.

  12. Theoretical model of intravascular paramagnetic tracers effect on tissue relaxation

    DEFF Research Database (Denmark)

    Kjølby, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij G

    2006-01-01

    that the relaxivity of intravascular contrast agents depends significantly on the host tissue. This agrees with experimental data by Johnson et al. (Magn Reson Med 2000;44:909). In particular, the present results suggest a several-fold increase in the relaxivity of Gd-based contrast agents in brain tissue compared...... with bulk blood. The enhancement of relaxation in tissue is due to the contrast in magnetic susceptibility between blood vessels and parenchyma induced by the presence of paramagnetic tracer. Beyond the perfusion measurements, the results can be applied to quantitation of functional MRI and to vessel size......The concentration of MRI tracers cannot be measured directly by MRI and is commonly evaluated indirectly using their relaxation effect. This study develops a comprehensive theoretical model to describe the transverse relaxation in perfused tissue caused by intravascular tracers. The model takes...

  13. Improvement of tissue analysis and classification using optical coherence tomography combined with Raman spectroscopy

    Science.gov (United States)

    Liu, Chih-Hao; Qi, Ji; Lu, Jing; Wang, Shang; Wu, Chen; Shih, Wei-Chuan; Larin, Kirill V.

    2014-02-01

    Optical coherence tomography (OCT) is an optical imaging technique that is capable of performing high-resolution (approaching the histopathology level) and real-time imaging of tissues without use of contrast agents. Based on these advantages, the pathological features of tumors (in micro scale) can be identified during resection surgery. However, the accuracy of tumor margin prediction still needs to be enhanced for assisting the judgment of surgeons. In this regard, we present a two-dimensional computational method for advanced tissue analysis and characterization based on optical coherence tomography (OCT) and Raman spectroscopy (RS). The method combines the slope of OCT intensity signal and the Principal component (PC) of RS, and relies on the tissue optical attenuation and chemical ingredients for the classification of tissue types. Our pilot experiments were performed on mouse kidney, liver and small intestine. Results demonstrate the improvement of the tissue differentiation compared with the analysis only based on the OCT detection. This combined OCT/RS method is potentially useful as a novel optical biopsy technique for cancer detection.

  14. Microprocessor-controlled optical stimulating device to improve the gait of patients with Parkinson's disease.

    Science.gov (United States)

    Ferrarin, M; Brambilla, M; Garavello, L; Di Candia, A; Pedotti, A; Rabuffetti, M

    2004-05-01

    Different types of visual cue for subjects with Parkinson's disease (PD) produced an improvement in gait and helped some of them prevent or overcome freezing episodes. The paper describes a portable gait-enabling device (optical stimulating glasses (OSGs) that provides, in the peripheral field of view, different types of continuous optic flow (backward or forward) and intermittent stimuli synchronised with external events. The OSGs are a programmable, stand-alone, augmented reality system that can be interfaced with a PC for program set-up. It consists of a pair of non-corrective glasses, equipped with two matrixes of 70 micro light emitting diodes, one on each side, controlled by a microprocessor. Two foot-switches are used to synchronise optical stimulation with specific gait events. A pilot study was carried out on three PD patients and three controls, with different types of optic flow during walking along a fixed path. The continuous optic flow in the forward direction produced an increase in gait velocity in the PD patients (up to + 11% in average), whereas the controls had small variations. The stimulation synchronised with the swing phase, associated with an attentional strategy, produced a remarkable increase in stride length for all subjects. After prolonged testing, the device has shown good applicability and technical functionality, it is easily wearable and transportable, and it does not interfere with gait.

  15. Design of low noise transimpedance amplifier for intravascular ultrasound

    KAUST Repository

    Reda, Dina

    2009-11-01

    In this paper, we study transimpedance amplifiers for capacitive sensing applications with a focus on Intravascular Ultra Sound (IVUS). We employ RF noise cancellation technique on capacitive feedback based transimpedance amplifiers. This technique eliminates the input-referred noise of TIAs completely and enhances the dynamic range of front-end electronics. Simulation results verify the proposed technique used in two different TIA topologies employing shunt-shunt feedback. ©2009 IEEE.

  16. Intravascular papillary endothelial hyperplasia: An unusual histopathological entity.

    Science.gov (United States)

    Mahapatra, Qury S; Sahai, Kavita; Malik, Ajay; Mani, N S

    2015-01-01

    Intravascular papillary endothelial hyperplasia (Masson's tumor) is a benign lesion of the skin and subcutaneous tissue consisting of a reactive proliferation of endothelial cells with papillary formations related to a thrombus. It poses a diagnostic challenge as the clinical signs and symptoms are nonspecific and may mimic a soft tissue sarcoma. The diagnosis is based on histopathology. Here we report two cases of Masson's hemangioma occurring on the upper lip and on the left hand.

  17. Intravascular papillary endothelial hyperplasia: An unusual histopathological entity

    Directory of Open Access Journals (Sweden)

    Qury S Mahapatra

    2015-01-01

    Full Text Available Intravascular papillary endothelial hyperplasia (Masson′s tumor is a benign lesion of the skin and subcutaneous tissue consisting of a reactive proliferation of endothelial cells with papillary formations related to a thrombus. It poses a diagnostic challenge as the clinical signs and symptoms are nonspecific and may mimic a soft tissue sarcoma. The diagnosis is based on histopathology. Here we report two cases of Masson′s hemangioma occurring on the upper lip and on the left hand.

  18. Intravascular papillary endothelial hyperplasia of the mandibular lingual mucosa

    Institute of Scientific and Technical Information of China (English)

    Benay Tokman; (S)ebnem (S)im(s)ek; Erkan Erkmen; Tülin Oygur

    2004-01-01

    @@ In 1923, Masson1 described an unusual papillary endothelial proliferation that he named as "hemangioendotheliome vegetant intravasculaire". In 1976, Clearkin and Enzinger2 coined the term intravascular papillary endothelial hyperplasia (IPEH) that is now in use. This term refers to the presence of endothelium lined papillary projections within a vascular space. Characteristically, the papillary structures are composed of a single layer of swollen or plump endothelial cells without cellular pleomorphism, mitotic activity or necrosis.

  19. Silent intravascular lymphoma initially manifesting as a unilateral adrenal incidentaloma.

    Science.gov (United States)

    Takahashi, Yoshiko; Iida, Keiji; Hino, Yasuhisa; Ohara, Takeshi; Kurahashi, Toshifumi; Tashiro, Takashi; Chihara, Kazuo

    2012-01-01

    Intravascular large B-cell lymphoma (IVLBCL) is a rare subtype of malignant lymphoma. Although the involvement of adrenal glands in IVLBCL is often observed, primary adrenal IVLBCL is rare. Most reported cases of adrenal IVLBCL showed bilateral lesions resulting in rapidly progressive adrenal failure and poor prognosis. Here, we report a case of slowly progressive primary adrenal IVLBCL manifesting initially with unilateral adrenal incidentaloma. This case is a silent IVLBCL and shows that the enlargement of both adrenal glands can be followed.

  20. Central Venous Catheter Intravascular Malpositioning: Causes, Prevention, Diagnosis, and Correction.

    Science.gov (United States)

    Roldan, Carlos J; Paniagua, Linda

    2015-09-01

    Despite the level of skill of the operator and the use of ultrasound guidance, central venous catheter (CVC) placement can result in CVC malpositioning, an unintended placement of the catheter tip in an inadequate vessel. CVC malpositioning is not a complication of central line insertion; however, undiagnosed CVC malpositioning can be associated with significant morbidity and mortality. The objectives of this review were to describe factors associated with intravascular malpositioning of CVCs inserted via the neck and chest and to offer ways of preventing, identifying, and correcting such malpositioning. A literature search of PubMed, Cochrane Library, and MD Consult was performed in June 2014. By searching for "Central line malposition" and then for "Central venous catheters intravascular malposition," we found 178 articles written in English. Of those, we found that 39 were relevant to our objectives and included them in our review. According to those articles, intravascular CVC malpositioning is associated with the presence of congenital and acquired anatomical variants, catheter insertion in left thoracic venous system, inappropriate bevel orientation upon needle insertion, and patient's body habitus variants. Although plain chest radiography is the standard imaging modality for confirming catheter tip location, signs and symptoms of CVC malpositioning even in presence of normal or inconclusive conventional radiography findings should prompt the use of additional diagnostic methods to confirm or rule out CVC malpositioning. With very few exceptions, the recommendation in cases of intravascular CVC malpositioning is to remove and relocate the catheter. Knowing the mechanisms of CVC malpositioning and how to prevent, identify, and correct CVC malpositioning could decrease harm to patients with this condition.

  1. Central Venous Catheter Intravascular Malpositioning: Causes, Prevention, Diagnosis, and Correction

    Directory of Open Access Journals (Sweden)

    Carlos J. Roldan

    2015-10-01

    Full Text Available Despite the level of skill of the operator and the use of ultrasound guidance, central venous catheter (CVC placement can result in CVC malpositioning, an unintended placement of the catheter tip in an inadequate vessel. CVC malpositioning is not a complication of central line insertion; however, undiagnosed CVC malpositioning can be associated with significant morbidity and mortality. The objectives of this review were to describe factors associated with intravascular malpositioning of CVCs inserted via the neck and chest and to offer ways of preventing, identifying, and correcting such malpositioning. A literature search of PubMed, Cochrane Library, and MD Consult was performed in June 2014. By searching for “Central line malposition” and then for “Central venous catheters intravascular malposition,” we found 178 articles written in English. Of those, we found that 39 were relevant to our objectives and included them in our review. According to those articles, intravascular CVC malpositioning is associated with the presence of congenital and acquired anatomical variants, catheter insertion in left thoracic venous system, inappropriate bevel orientation upon needle insertion, and patient’s body habitus variants. Although plain chest radiography is the standard imaging modality for confirming catheter tip location, signs and symptoms of CVC malpositioning even in presence of normal or inconclusive conventional radiography findings should prompt the use of additional diagnostic methods to confirm or rule out CVC malpositioning. With very few exceptions, the recommendation in cases of intravascular CVC malpositioning is to remove and relocate the catheter. Knowing the mechanisms of CVC malpositioning and how to prevent, identify, and correct CVC malpositioning could decrease harm to patients with this condition.

  2. Asian-variant intravascular lymphoma in the African race

    OpenAIRE

    Holly Geyer; Nina Karlin; Brian Palen; Ruben Mesa

    2012-01-01

    Intravascular large B-cell lymphoma (IVLBCL) is an exceptionally rare form of non- Hodgkin lymphoma (NHL) distinguished by the preferential growth of neoplastic cells within blood vessel lumen. Challenging to detect and deemed disseminated at diagnosis, this condition is characterized by a highly aggressive, inconspicuous course with a high mortality rate. We describe the case of a 48 year-old African-American female presenting with a two month history of low-grade fevers and malaise. Laborat...

  3. The improvement of laser induced damage resistance of optical workpiece surface by hydrodynamic effect polishing

    Science.gov (United States)

    Peng, Wenqiang; Guan, Chaoliang; Li, Shengyi; Wang, Zhuo

    2016-10-01

    Surface and subsurface damage in optical element will greatly decrease the laser induced damage threshold (LIDT) in the intense laser optical system. Processing damage on the workpiece surface can be inevitably caused when the material is removed in brittle or plastic mode. As a non-contact polishing technology, hydrodynamic effect polishing (HEP) shows very good performance on generating an ultra-smooth surface without damage. The material is removed by chemisorption between nanoparticle and workpiece surface in the elastic mode in HEP. The subsurface damage and surface scratches can be effectively removed after the polishing process. Meanwhile ultra-smooth surface with atomic level surface roughness can be achieved. To investigate the improvement of LIDT of optical workpiece, polishing experiment was conducted on a magnetorheological finishing (MRF) silica glass sample. AFM measurement results show that all the MRF directional plastic marks have been removed clearly and the root-mean-square (rms) surface roughness has decreased from 0.673nm to 0.177nm after HEP process. Laser induced damage experiment was conducted with laser pulse of 1064nm wavelength and 10ns time width. Compared with the original state, the LEDT of the silica glass sample polished by HEP has increased from 29.78J/cm2 to 45.47J/cm2. It demonstrates that LIDT of optical element treated by HEP can be greatly improved for ultra low surface roughness and nearly defect-free surface/subsurface.

  4. Intravascular Talcosis due to Intravenous Drug Use Is an Underrecognized Cause of Pulmonary Hypertension

    Directory of Open Access Journals (Sweden)

    Christopher C. Griffith

    2012-01-01

    Full Text Available Intravenous injection of illegal drugs or medications meant for oral administration can cause granulomatous disease of the lung. This intravascular talcosis results in pulmonary fibrosis and pulmonary hypertension. Nine cases of histologically confirmed intravascular talcosis were reviewed with specific attention given to the clinical histories in these patients. Five autopsy cases were included in this series with detailed investigation in the anatomic features associated with intravascular talcosis and pulmonary hypertension. All nine patients showed perivascular and/or intravascular deposition of polarizable foreign material in their lungs. Intravascular talcosis as a result of previous intravenous drug use was not clinically suspected in any patient despite clinically diagnosed pulmonary hypertension in five. All patients showed dilatation of the right and left heart, but none had dilatation of the aortic valve. Congestive heart failure with hepatosplenomegaly was also common. We conclude that intravascular talcosis is an underdiagnosed cause of pulmonary hypertension in patients with known history of intravenous drug use.

  5. Transparent conductor-embedding nanocones for selective emitters: optical and electrical improvements of Si solar cells.

    Science.gov (United States)

    Kim, Joondong; Yun, Ju-Hyung; Kim, Hyunyub; Cho, Yunae; Park, Hyeong-Ho; Kumar, M Melvin David; Yi, Junsin; Anderson, Wayne A; Kim, Dong-Wook

    2015-03-19

    Periodical nanocone-arrays were employed in an emitter region for high efficient Si solar cells. Conventional wet-etching process was performed to form the nanocone-arrays for a large area, which spontaneously provides the graded doping features for a selective emitter. This enables to lower the electrical contact resistance and enhances the carrier collection due to the high electric field distribution through a nanocone. Optically, the convex-shaped nanocones efficiently reduce light-reflection and the incident light is effectively focused into Si via nanocone structure, resulting in an extremely improved the carrier collection performances. This nanocone-arrayed selective emitter simultaneously satisfies optical and electrical improvement. We report the record high efficiency of 16.3% for the periodically nanoscale patterned emitter Si solar cell.

  6. Harmonic detection of magnetic resonance for sensitivity improvement of optical atomic magnetometers

    Science.gov (United States)

    Ranjbaran, M.; Tehranchi, M. M.; Hamidi, S. M.; Khalkhali, S. M. H.

    2017-02-01

    Highly sensitive atomic magnetometers use optically detected magnetic resonance of atomic spins to measure extremely weak magnetic field changes. The magnetometer sensitivity is directly proportional to the ratio of intensity to line-shape of the resonance signal. To obtain narrower resonance signal, we implemented harmonic detection of magnetic resonance method in Mx configuration. The nonlinear spin polarization dynamics in detection of the higher harmonics were employed in phenomenological Bloch equations. The measured and simulated harmonic components of the resonance signals in frequency domain yielded significantly narrower line-width accompanying much improved sensitivity. Our results confirm the sensitivity improvement by a factor of two in optical atomic magnetometer via second harmonic signal which can open a new insight in the weak magnetic field measurement system design.

  7. Improving performance of optical fibre chaotic communication by dispersion compensation techniques

    Institute of Scientific and Technical Information of China (English)

    Zhang Jian-Zhong; Wang Yun-Cai; Wang An-Bang

    2008-01-01

    This paper numerically investigates the effects of dispersion on optical fibre chaotic communication,and proposes a dispersion compensation scheme to improve the performance of optical fibre chaotic communication system.The obtained results show that the transmitter-receiver synchronization progressively degrades and the signal-to-noise ratio of the recovered message deteriorates as the fibre length increases due to the dispersion accumulation.Two segments of 2.5-km dispersion-compensating fibres are symmetrically placed at both ends of a segment of 245-km nonzero dispersionshifted fibre with low dispersion in one compensation period.The numerical results show that the signal-to-noise ratio of the extracted 1 GHz sinusoidal message is improved from-2.92 dB to 15.38 dB by this dispemion compensation for the transmission distance of 500 km.

  8. Improvement of PEP-II Linear Optics with a MIA-Derived Virtual Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Cerio, B.; /Colgate U.

    2006-08-30

    In several past studies, model independent analysis, in conjunction with a virtual accelerator model, has been successful in improving PEP-II linear geometric optics. In many cases, optics improvement yielded an increase in machine luminosity. In this study, an updated characterization of linear optics is presented. With the PEP-II beam position monitor (BPM) system, four independent beam centroid orbits were extracted and used to determine phase advances and linear Green's functions among BPM locations. A magnetic lattice model was then constructed with a singular value decomposition-enhanced least-square fitting of phase advances and Green's functions, which are functions of quadrupole strengths, sextupole feed-downs, as well as BPM errors, to the corresponding measured quantities. The fitting process yielded a machine model that matched the measured linear optics of the real machine and was therefore deemed the virtual accelerator. High beta beat, as well as linear coupling, was observed in both LER and HER of the virtual accelerator. Since there was higher beta beating in LER, focus was shifted to the improvement of this ring. By adjusting select quadrupoles of the virtual LER and fitting the resulting beta functions and phase advances to those of the desired lattice, the average beta beat of the virtual machine was effectively reduced. The new magnet configuration was dialed into LER on August 10, 2006, and beta beat was reduced by a factor of three. After fine tuning HER to match the improved LER for optimal collision, a record peak luminosity of 12.069 x 10{sup 33} cm{sup -2} s{sup -1} was attained on August 16, 2006.

  9. Disseminated intravascular large-cell lymphoma with initial presentation mimicking Guillain-Barré syndrome.

    Science.gov (United States)

    Jiang, Qin Li; Pytel, Peter; Rowin, Julie

    2010-07-01

    We report a patient with intravascular large B-cell lymphoma who initially presented with acute ascending weakness and sensory changes. Electrodiagnostic testing and cerebral spinal fluid (CSF) studies were initially suggestive of a demyelinating polyneuropathy. Further clinical evaluation and testing were consistent with mononeuropathy multiplex. Autopsy revealed disseminated intravascular large-cell lymphoma. Intravascular large-cell lymphoma should be considered in the differential diagnosis of a rapidly evolving neuropathy associated with other organ involvement.

  10. Hand-held optical imager (Gen-2): improved instrumentation and target detectability.

    Science.gov (United States)

    Gonzalez, Jean; Decerce, Joseph; Erickson, Sarah J; Martinez, Sergio L; Nunez, Annie; Roman, Manuela; Traub, Barbara; Flores, Cecilia A; Roberts, Seigbeh M; Hernandez, Estrella; Aguirre, Wenceslao; Kiszonas, Richard; Godavarty, Anuradha

    2012-08-01

    Hand-held optical imagers are developed by various researchers towards reflectance-based spectroscopic imaging of breast cancer. Recently, a Gen-1 handheld optical imager was developed with capabilities to perform two-dimensional (2-D) spectroscopic as well as three-dimensional (3-D) tomographic imaging studies. However, the imager was bulky with poor surface contact (~30%) along curved tissues, and limited sensitivity to detect targets consistently. Herein, a Gen-2 hand-held optical imager that overcame the above limitations of the Gen-1 imager has been developed and the instrumentation described. The Gen-2 hand-held imager is less bulky, portable, and has improved surface contact (~86%) on curved tissues. Additionally, the forked probe head design is capable of simultaneous bilateral reflectance imaging of both breast tissues, and also transillumination imaging of a single breast tissue. Experimental studies were performed on tissue phantoms to demonstrate the improved sensitivity in detecting targets using the Gen-2 imager. The improved instrumentation of the Gen-2 imager allowed detection of targets independent of their location with respect to the illumination points, unlike in Gen-1 imager. The developed imager has potential for future clinical breast imaging with enhanced sensitivity, via both reflectance and transillumination imaging.

  11. Intravascular ultrasound in the endovascular management of atherosclerotic peripheral occlusive disease.

    Science.gov (United States)

    Colli, Rosa; Di Stasi, Carmine; Modugno, Pietro; Orlando, Giuseppe; Cavallaro, Antonio

    2004-01-01

    This study is a retrospective analysis of the impact of intravascular ultrasound in addiction to conventional angiography in 36 patients with 55 stenotic peripheral arterial lesions treated with angioplasty and/or stenting. Before treatment, intravascular ultrasound imaging showed that the vessel diameter was underestimated with angiography in 6 cases. The correlation index between angiography and intravascular ultrasound measurements, however, was significant in 27 arterial lesions. After endovascular treatment, angiography showed 3 vessel dissections and no incomplete stent deployment, whereas intravascular ultrasound showed 15 dissections and 5 instances of stent underdeployment. If we consider the intravascular ultrasound data as the gold standard, the specificity of angiography is 100%, while its sensitivity is 56% for vessel dissection and 75% for stent deployment. In the follow up of the 16 patients treated for iliac lesions with intravascular ultrasound control, re-stenosis occurred in 5% (primary patency 94.7%); in a control group of 15 patients treated in the same period without intravascular ultrasound control, re-stenosis occurred in 15.8% (primary patency 83.4%, difference not statistically significant). In conclusion, in the peripheral arteries intravascular ultrasound is more accurate than arteriography in evaluating dissection and stent deployment, but the routine use of intravascular ultrasound in every case of iliac PTA or stenting would not appear justified.

  12. Intravascular large B-cell lymphoma presenting with fulminant pseudomembranous colitis.

    Science.gov (United States)

    Wang, Tao; Ghaffar, Hasan; Grin, Andrea

    2013-05-01

    Intravascular large B-cell lymphoma is a rare entity that usually presents in late stages with non-specific symptoms. We present a case of an incidentally discovered intravascular large B-cell lymphoma in a 78-year-old man who underwent colectomy for medically refractory pseudomembranous colitis. The malignant lymphocytes were preferentially localized to small colonic submucosal vasculature, without any evidence of an extravascular tumor mass. The gastrointestinal system is an exceeding rare initial diagnostic site for intravascular lymphoma, and presentation with pseudomembranous colitis has not been previously reported. We discuss the current definition of intravascular lymphoma, clinicopathological variants, differential diagnoses, as well as current therapy.

  13. Optical reflectivity and hardness improvement of hafnium nitride films via tantalum alloying

    Science.gov (United States)

    Gu, Zhiqing; Huang, Haihua; Zhang, Sam; Wang, Xiaoyi; Gao, Jing; Zhao, Lei; Zheng, Weitao; Hu, Chaoquan

    2016-12-01

    It is found that incorporation of tantalum in a hafnium nitride film induces a tunable optical reflectivity and improves the hardness. The underlying mechanism can be illustrated by a combination of experiments and first-principles calculations. It is shown that the evolution of optical reflectivity and the increase in hardness arise from the formation of Hf1-xTaxN solid solutions and the resulting changes in the electronic structure. The increase in infrared reflectance originates from the increase in concentration of free electrons (n) because Ta (d3s2) has one more valence electron than Hf (d2s2). The sharp blue-shift in cutoff wavelength is attributed to the increase in n and the appearance of t2g → eg interband absorption. These results suggest that alloying of a second transition metal renders an effective avenue to improve simultaneously the optical and mechanical properties of transition metal nitride films. This opens up a door in preparing high-reflectance yet hard films.

  14. RF-modulated pulsed fiber optic lidar transmitter for improved underwater imaging and communications

    Science.gov (United States)

    Kimpel, F.; Chen, Y.; Fouron, J.-L.; Akbulut, M.; Engin, D.; Gupta, S.

    2011-03-01

    We present results on the design, development and initial testing of a fiber-optic based RF-modulated lidar transmitter operating at 532nm, for underwater imaging application in littoral waters. The design implementation is based on using state-of-the-art high-speed FPGAs, thereby producing optical waveforms with arbitrary digital-RF-modulated pulse patterns with carrier frequencies >= 3GHz, with a repetition rate of 0.5-1MHz, and with average powers >=5W (at 532nm). Use of RF-modulated bursts above 500MHz, instead of single optical pulse lidar detection, reduces the effect of volumetric backscatter for underwater imaging application, leading to an improved signal-to-noise-ratio (SNR) and contrast, for a given range. Initial underwater target detection tests conducted at Patuxent River Naval Air Station, MD, in a large water-tank facility, validates the advantages of this hybrid-lidar-radar (HLR) approach for improved underwater imaging, over a wide range of turbidity levels and both white and black targets. The compact, robust and power-efficient fiber laser architecture lends very well to lidar sensor integration on unmanned-underwater-vehicle (UUV) platforms. HLR transmitters can also provide similar advantages in active-sensing situations dominated by continuous backscatter, e.g. underwater communications, imaging through smoke and fire environment, rotor-craft landing in degraded visual environment, and pointing-tracking of active-EO sensors through fog.

  15. Improved Reduced Models for Single-Pass and Reflective Semiconductor Optical Amplifiers

    CERN Document Server

    Dúill, Seán P Ó

    2014-01-01

    We present highly accurate and easy to implement, improved lumped semiconductor optical amplifier (SOA) models for both single-pass and reflective semiconductor optical amplifiers (RSOA). The key feature of the model is the inclusion of the internal losses and we show that a few subdivisions are required to achieve an accuracy of 0.12 dB. For the case of RSOAs, we generalize a recently published model to account for the internal losses that are vital to replicate observed RSOA behavior. The results of the improved reduced RSOA model show large overlap when compared to a full bidirectional travelling wave model over a 40 dB dynamic range of input powers and a 20 dB dynamic range of reflectivity values. The models would be useful for the rapid system simulation of signals in communication systems, i.e. passive optical networks that employ RSOAs, signal processing using SOAs and for implementing digital back propagation to undo amplifier induced signal distortions.

  16. Overview and Improving Fiber Optic Gyroscope Based on MEMS/NEMS Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Bo; Kahn, M T E [Electrical Engineering Department, Cape Peninsula University of Technology, BELLVILLE CAMPUS, Cape Town, 7535 (South Africa); Electrical Engineering Department, Cape Peninsula University of Technology, BELLVILLE CAMPUS, Cape Town, 7535 (South Africa)

    2006-04-01

    The measurement of the rotation of rigid solids is of considerable interest in a number of areas. Rotation detectors are not only used in aircraft, missiles etc. military fields have also been developed for new civil fields such as automobile navigation, antenna stabilization, crane control, unmanned vehicle control, wind and renewable energy platform stabilization. In this paper, the fundamental operations of fiber-optic gyroscopes are reviewed. Performance-limiting phenomena are discussed along with methods to reduce their effect on the rotation-rate signal. Current technology and performance of new demodulate systems are presented applicable to MEMS technology. The FOG with scanning phase-shift demodulates technology based on anti-noise filter circuit improvement of DSP algorithm is proposed in this paper. New methods, which are used to fabricate the nanometer optical fiber, are discussed.

  17. Improved optical sintering efficiency at the contacts of silver nanowires encapsulated by a graphene layer.

    Science.gov (United States)

    Yang, Seung-Bok; Choi, HongKyw; Lee, Da Som; Choi, Choon-Gi; Choi, Sung-Yool; Kim, Il-Doo

    2015-03-18

    Graphene/silver nanowire (AgNWs) stacked electrodes, i.e., graphene/AgNWs, are fabricated on a glass substrate by air-spray coating of AgNWs followed by subsequent encapsulation via a wet transfer of single-layer graphene (SLG) and multilayer graphene (MLG, reference specimen) sheets. Here, graphene is introduced to improve the optical sintering efficiency of a xenon flash lamp by controlling optical transparency and light absorbing yield in stacked graphene/AgNW electrodes, facilitating the fusion at contacts of AgNWs. Intense pulsed light (IPL) sintering induced ultrafast (sintering is an efficient way to provide fast welding of Ag wire-to-wire junctions in stacked electrodes of graphene/AgNWs, leading to enhanced conductivity as well as superior long-term stability under oxygen and sulfur atmospheres. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Azide-derivatized gold nanosphere "clicked" to indium and zinc phthalocyanines for improved nonlinear optical limiting

    Science.gov (United States)

    Bankole, Owolabi M.; Nyokong, Tebello

    2017-05-01

    We report on the conjugation of azide-derivatized gold nanoparticles (AuNPs) to alkyne moieties of ZnPc and InPc via azide-alkyne Huisgen cycloaddition reaction to form phthalocyanines-AuNPs (MPc-AuNPs) conjugates. The detailed structural characterizations of the composites were in good agreement with the expected results. The nonlinear absorption coefficients and other nonlinear optical limiting parameters were almost two times larger for the conjugates compared to free phthalocyanines. We established direct relationship between improved photophysical characterizations and enhanced nonlinear effects of reverse saturable absorption mechanisms favoured by excited triplet absorption of the phthalocyanines in the presence of AuNPs. The combination of InPc with AuNPs resulted in the lowest limiting intensity value of 0.06 J/cm2, hence the best performance in terms of optical limiting.

  19. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  20. Adaptive Light Modulation for Improved Resolution and Efficiency in All-Optical Pulse-Echo Ultrasound.

    Science.gov (United States)

    Alles, Erwin J; Colchester, Richard J; Desjardins, Adrien E

    2016-01-01

    In biomedical all-optical pulse-echo ultrasound systems, ultrasound is generated with the photoacoustic effect by illuminating an optically absorbing structure with a temporally modulated light source. Nanosecond range laser pulses are typically used, which can yield bandwidths exceeding 100 MHz. However, acoustical attenuation within tissue or nonuniformities in the detector or source power spectra result in energy loss at the affected frequencies and in a reduced overall system efficiency. In this work, a laser diode is used to generate linear and nonlinear chirp optical modulations that are extended to microsecond time scales, with bandwidths constrained to the system sensitivity. Compared to those obtained using a 2-ns pulsed laser, pulse-echo images of a phantom obtained using linear chirp excitation exhibit similar axial resolution (99 versus 92 μm, respectively) and signal-to-noise ratios (SNRs) (10.3 versus 9.6 dB). In addition, the axial point spread function (PSF) exhibits lower sidelobe levels in the case of chirp modulation. Using nonlinear (time-stretched) chirp excitations, where the nonlinearity is computed from measurements of the spectral sensitivity of the system, the power spectrum of the imaging system was flattened and its bandwidth broadened. Consequently, the PSF has a narrower axial extent and still lower sidelobe levels. Pulse-echo images acquired with time-stretched chirps as optical modulation have higher axial resolution (64 μm) than those obtained with linear chirps, at the expense of a lower SNR (6.8 dB). Using a linear or time-stretched chirp, the conversion efficiency from optical power to acoustical pressure improved by a factor of 70 or 61, respectively, compared to that obtained with pulsed excitation.

  1. Disseminated intravascular coagulation: testing and diagnosis.

    Science.gov (United States)

    Wada, Hideo; Matsumoto, Takeshi; Yamashita, Yoshiki; Hatada, Tsuyoshi

    2014-09-25

    Abnormalities of the hemostatic system in patients with DIC result from the sum of vectors for hypercoagulation and hyperfibrinolysis. DIC is classified into hyperfibrinolysis, hypercoagulation, massive bleeding or nonsymptomatic types according to the balance of the two vectors. Both the antithrombin (AT) and protein C (PC) levels are significantly low in patients with septic DIC, and reduced amounts of AT and PC result in the lack of inhibition of thrombin and activated FVIII, respectively. Thrombin activates FVIII, while activated FVIII accelerates the coagulation pathway to generate thrombin; thus activation of the coagulation system persists. Three sets of diagnostic criteria have been established by the Japanese Ministry of Health, Labour and Welfare, International Society of Thrombosis and Haemostasis and Japanese Association for Acute Medicine, respectively. Although these three diagnostic criteria score hemostatic abnormalities using similar global coagulation tests, the sensitivity and/or specificity for death differ. Treatment with AT or activated PC may not improve the outcomes of patients with sepsis at the early stage, although they may improve the outcomes in those with DIC. Therefore, new diagnostic criteria for determining the appropriate time to initiate anticoagulant treatment are required.

  2. Improved Algorithms for Accurate Retrieval of UV - Visible Diffuse Attenuation Coefficients in Optically Complex, Inshore Waters

    Science.gov (United States)

    Cao, Fang; Fichot, Cedric G.; Hooker, Stanford B.; Miller, William L.

    2014-01-01

    Photochemical processes driven by high-energy ultraviolet radiation (UVR) in inshore, estuarine, and coastal waters play an important role in global bio geochemical cycles and biological systems. A key to modeling photochemical processes in these optically complex waters is an accurate description of the vertical distribution of UVR in the water column which can be obtained using the diffuse attenuation coefficients of down welling irradiance (Kd()). The Sea UV Sea UVc algorithms (Fichot et al., 2008) can accurately retrieve Kd ( 320, 340, 380,412, 443 and 490 nm) in oceanic and coastal waters using multispectral remote sensing reflectances (Rrs(), Sea WiFS bands). However, SeaUVSeaUVc algorithms are currently not optimized for use in optically complex, inshore waters, where they tend to severely underestimate Kd(). Here, a new training data set of optical properties collected in optically complex, inshore waters was used to re-parameterize the published SeaUVSeaUVc algorithms, resulting in improved Kd() retrievals for turbid, estuarine waters. Although the updated SeaUVSeaUVc algorithms perform best in optically complex waters, the published SeaUVSeaUVc models still perform well in most coastal and oceanic waters. Therefore, we propose a composite set of SeaUVSeaUVc algorithms, optimized for Kd() retrieval in almost all marine systems, ranging from oceanic to inshore waters. The composite algorithm set can retrieve Kd from ocean color with good accuracy across this wide range of water types (e.g., within 13 mean relative error for Kd(340)). A validation step using three independent, in situ data sets indicates that the composite SeaUVSeaUVc can generate accurate Kd values from 320 490 nm using satellite imagery on a global scale. Taking advantage of the inherent benefits of our statistical methods, we pooled the validation data with the training set, obtaining an optimized composite model for estimating Kd() in UV wavelengths for almost all marine waters. This

  3. Method for Observing Intravascular BongHan Duct

    CERN Document Server

    Jiang, X; Shin, H; Lee, B; Choi, C; Soh, K; Cheun, B; Baik, K; Soh, K; Jiang, Xiaowen; Kim, Hee-kyeong; Shin, Hak-soo; Lee, Byong-chon; Choi, Chunho; Soh, Kyung-soon; Cheun, Byeung-soo; Baik, Ku-youn; Soh, Kwang-sup

    2002-01-01

    A method for observing intra blood vessel ducts which are threadlike bundle of tubules which form a part of the BongHan duct system. By injecting 10% dextrose solution at a vena femoralis one makes the intravascular BongHan duct thicker and stronger to be easily detectable after incision of vessels. The duct is semi-transparent, soft and elastic, and composed of smaller tubules whose diameters are of 10$\\mu$m order, which is in agreement with BongHan theory.

  4. Primary Intrarenal Neuroblastoma with Hypertension and Disseminated Intravascular Coagulation

    Directory of Open Access Journals (Sweden)

    Bibi Shahin Shamsian

    2013-01-01

    Full Text Available The primary intrarenal neuroblastoma (IRNB is a rare condition. Intrarenal neuroblastoma typically results from direct renal invasion from an adrenal neuroblastoma, but true intrarenal neuroblastoma originates either sequestered adrenal rests during the fetal life or intrarenal sympathetic ganglia. Clinical, radiological, and pathological correlation is very essential for diagnosis and appropriate management of this type of unusual cases. The distinction of this rare tumor from Wilms’ tumor is an important challenge since both tumors have major differences in prognostic and therapeutic response. We present a 3-year-old boy of primary intrarenal neuroblastoma with extensive abdominal and mediastinal mass, persistent hypertension, and disseminated intravascular coagulation (DIC.

  5. Protection against high intravascular pressure in giraffe legs

    DEFF Research Database (Denmark)

    Petersen, Karin K; Hørlyck, Arne; Østergaard, Kristine Hovkjær

    2013-01-01

    The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated in 11 giraffes whether large and small arteries in the legs and the tight fascia protect leg capillaries. Ultrasound imaging of foreleg arteries in anesthetized giraffes and ex vivo examination....... All three findings can contribute to protection of the capillaries in giraffe legs from a high arterial pressure....... revealed abrupt thickening of the arterial wall and a reduction of its internal diameter just below the elbow. At and distal to this narrowing, the artery constricted spontaneously and in response to norepinephrine and intravascular pressure recordings revealed a dynamic, viscous pressure drop along...

  6. Histamine release and endothelial leakage from an intravascular contrast medium

    Energy Technology Data Exchange (ETDEWEB)

    Raininko, R.

    1981-04-01

    The endothelial injury produced by meglumine iodamide was studied in the rat aorta. A mixture of blood and contrast medium was more toxic to the endothelium than the pure contrast agent. This difference disappeared after premedication with antihistamine, which did not affect the injury produced by the pure contrast agent. Meglumine iodamide appears to cause a release of histamine from blood but not from the aortic endothelium nor from surrounding tissues in amounts demonstrable by this method. Leucocytes are a source of histamine after intravascular contrast medium administration.

  7. Removal of Chronic Intravascular Blood Clots using Liquid Plasma

    Science.gov (United States)

    Jung, Jae-Chul; Choi, Myeong; Koo, Il; Yu, Zengqi; Collins, George

    2011-10-01

    An electrical embolectomy device for removing chronic intravascular blood clots using liquid plasma under saline environment was demonstrated. We employed a proxy experimental blood clot model of deep vein thrombosis (DVT) and actual equine blood clot. Thermal damage to contiguous tissue and the collagen denaturing via the plasma irradiation were investigated by histological analysis using birefringence of the tissue and verified by FT-IR spectroscopic study, respectively, which showed the high removal rate up to 2 mm per minute at room temperature and small thermal damage less than 200 μm.

  8. Silent Intravascular Lymphoma Initially Manifesting as a Unilateral Adrenal Incidentaloma

    Directory of Open Access Journals (Sweden)

    Yoshiko Takahashi

    2012-01-01

    Full Text Available Intravascular large B-cell lymphoma (IVLBCL is a rare subtype of malignant lymphoma. Although the involvement of adrenal glands in IVLBCL is often observed, primary adrenal IVLBCL is rare. Most reported cases of adrenal IVLBCL showed bilateral lesions resulting in rapidly progressive adrenal failure and poor prognosis. Here, we report a case of slowly progressive primary adrenal IVLBCL manifesting initially with unilateral adrenal incidentaloma. This case is a silent IVLBCL and shows that the enlargement of both adrenal glands can be followed.

  9. Application of tissue characterization in intravascular ultrasound imaging

    Science.gov (United States)

    Mullen, William L.; Fitzgerald, Peter J.; Yock, Paul G.

    1994-05-01

    Current intravascular ultrasound imaging technology is able to determine the extent and distribution of pathologic processes within the vessel wall, but is not highly sensitive in discriminating between certain types of tissue. `Tissue characterization' refers to a set of computer-based techniques that utilize features of the ultrasound signal beyond basic amplitude to help define the composition of the tissue of interest. This technique involves quantitative analysis of the ultrasound signals reflected from tissue before these signals pass through the processing steps in the ultrasound instrument.

  10. An improved calibration method using third order polarization mode crosstalk for optical coherence domain polarimetry

    Science.gov (United States)

    Yang, Zhe; Yang, Jun; Zhang, Haoliang; Li, Hanyang; Peng, Feng; Yuan, Yonggui; Cheng, Yongqing; Yuan, Libo

    2017-04-01

    We propose an improved optical coherence domain polarimetry (OCDP) calibration scheme by using polarization mode crosstalk (PMC). The scheme can be used to calibrate the OCDP system's measurement result about intensity of PMC. The intensity of 1st order PMCs are measured by polarization extinction ratio (PER) meter as the scale to transfer the standard into OCDP system, and the higher order PMCs formed by 1st orders are used to expand the scale. Specifying alignment angle of joint points and analyzer, we successfully use 3rd order PMCs and expand the range of calibration over -100 dB.

  11. IMPROVEMENT OF THE CRYSTALLINITY AND OPTICAL PARAMETERS OF ZnO FILM WITH ALUMINUM DOPING

    OpenAIRE

    Ilican, Saliha

    2016-01-01

    In this study, the undoped and Aluminum (Al) doped (1% and 3%) zinc oxide (ZnO) films were prepared by sol gel method via spin coating onto glass substrates. To investigate the structural and optical properties of the films, it was used to X-ray diffractometer and UV-vis spectrophotometer, respectively. The prepared ZnO films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the (002) plane. The crystalline quality of ZnO film was improved by...

  12. Strategies to Improve the Accuracy of Mars-GRAM Sensitivity Studies at Large Optical Depths

    Science.gov (United States)

    Justh, Hilary L.; Justus, Carl G.; Badger, Andrew M.

    2010-01-01

    The poster provides an overview of techniques to improve the Mars Global Reference Atmospheric Model (Mars-GRAM) sensitivity. It has been discovered during the Mars Science Laboratory (MSL) site selection process that the Mars Global Reference Atmospheric Model (Mars-GRAM) when used for sensitivity studies for TES MapYear = 0 and large optical depth values such as tau = 3 is less than realistic. A preliminary fix has been made to Mars-GRAM by adding a density factor value that was determined for tau = 0.3, 1 and 3.

  13. Improvement of optical properties of TiO2 thin film treated with electron beam.

    Science.gov (United States)

    Shin, Joong-Hyeok; Lee, Byung Cheol; Woo, Hee-Gweon; Hwang, Kwang Ha; Jun, Jin

    2013-03-01

    Nanocrystalline titanium dioxide (TiO2) thin films on silicon wafer substrates were prepared by sol-gel spin coating process. The prepared thin films were treated with electron beam (1.1 MeV, 300 kGy) at air atmosphere. The effects of electron-beam (EB) irradiation on the structural and optical properties of the TiO2 thin films were investigated. The structures of all the TiO2 thin films by XRD analysis showed an anatase phase, and the phase remained unchanged within the investigating range of EB treatment. The thickness of the titania thin film decreased slightly with EB treatment whereas the porosity increased. The EB treatment of TiO2 thin film can increase the proportion of Ti3+ in Ti2p at the thin film surface. The optical transmittance of the film in the wavelength ranges of above 380 nm increased after the EB treatment while its refractive index decreased with increasing EB dose. Therefore, improvement of the optical properties could be due to the change in both surface chemistry and morphology of the TiO2 thin films affected by EB irradiation.

  14. Experimental verification of optically optimized CuGaSe2 top cell for improving chalcopyrite tandems

    Science.gov (United States)

    Schmid, M.; Caballero, R.; Klenk, R.; Krč, J.; Rissom, T.; Topi, M.; Lux-Steiner, M. Ch.

    2010-07-01

    An efficient tandem solar cell requires a top cell which is highly transparent below the energy gap of its absorber. Previously we had reported on a theoretically optimized CuGaSe2top cell stack based on realistic material properties. It promised a significant increase in optical transparency and, consequently, enhanced CuGaSe2/Cu(In,Ga)Se2tandem efficiency. Here we present the first steps taken towards the experimental realization of this optimized tandem. We started with a mechanically stacked device which achieved 8.5% efficiency. Optical measurements of the improved top cells and corresponding photo current densities of the filtered bottom cell are reported. The experimental findings are in agreement with the optical modeling. These data are used to assess the level of tandem performance that could be accomplished in the near future and to discuss the priorities of further research. This article has been previously published in PV Direct, the former name of EPJ Photovoltaics.

  15. Throughput Improvement In Wireless Mesh Networks By Integrating With Optical Network

    Directory of Open Access Journals (Sweden)

    Chakrapani gadde

    2012-06-01

    Full Text Available In the last decade wireless mesh networks (WMNs have emerged as a key technology for next generation wireless networking. Because of their advantages over other wireless networks, WMNs are undergoing rapid progress and inspiring numerous applications. One such application is to provide peer-to-peer communication for all the users who are distributed over some area. Since the users are connected in awireless multi-hop passion complete ubiquity is provided. But as the number of users accessing the network is increasing there could be a chance of experiencing more interference by each user due to the communication link of every other user. So in a wireless mesh network as the load increases the throughput of network is going to be decreased due to wireless interference by other users. To sustain this problem we are going to integrate the WMN with passive optical network (PON. The resulting hybrid network (Optical-wireless network could reduce the wireless hops of each user, so that we can reduce the total wireless interference experienced by each user resulting in improved network throughput. This paper aims to study the network throughput gain in Optical-wireless network subject to peer-to-peer communications.

  16. Improved Automatic Filtered Power Control Pumping Method for Uniform Shortpass Band in Optical Fiber Communications

    Science.gov (United States)

    Shen, Jyi-Lai; Huang, Hau-Min; Lee, Yueh-Chien; Huang, Chia-Chih; Lin, Huang-Cuang; Lin, Chin-Yuan

    2009-01-01

    To form a low noise figure and uniform shortpass band in optical fiber communications an improved automatic filtered power control (AFPC) pumping method is proposed here. A modulated single laser signal was entered in a closed feedback loop, in which the erbium-doped fiber amplifier (EDFA) was used as a part of the AFPC loop. Owing to the constant filtered signal and the quadrature phase shift delay inside the feedback loop, an optical pass band was uniformly formed. This EDFA attains high performance with a low noise figure simultaneously. The method was successfully applied to the fabrication of practical 12.0 m length of erbium-doped fiber pumped at 980 nm wavelength and 20 dBm power. Experiments prove that the signal gain of the loop remain flat in the range of 18.2 to 22.4 dB with a worst case error of ±0.5 dB and the noise figure was reduced by 2.2 dB at optimal, which correspond to a shortpass range of 40 nm band pass from 1525 nm to 1565 nm in wavelength. Of course, it should be possible to extent the system performance to all pumping configurations for semiconductor optical amplifiers. This provides the simplest and most economical way to transmit a well-defined band of modulated laser signal and to reject all other unwanted radiation.

  17. Correlation of breast tissue histology and optical signatures to improve margin assessment techniques

    Science.gov (United States)

    Kennedy, Stephanie; Caldwell, Matthew; Bydlon, Torre; Mulvey, Christine; Mueller, Jenna; Wilke, Lee; Barry, William; Ramanujam, Nimmi; Geradts, Joseph

    2016-06-01

    Optical spectroscopy is sensitive to morphological composition and has potential applications in intraoperative margin assessment. Here, we evaluate ex vivo breast tissue and corresponding quantified hematoxylin & eosin images to correlate optical scattering signatures to tissue composition stratified by patient characteristics. Adipose sites (213) were characterized by their cell area and density. All other benign and malignant sites (181) were quantified using a grid method to determine composition. The relationships between mean reduced scattering coefficient (), and % adipose, % collagen, % glands, adipocyte cell area, and adipocyte density were investigated. These relationships were further stratified by age, menopausal status, body mass index (BMI), and breast density. We identified a positive correlation between and % collagen and a negative correlation between and age and BMI. Increased collagen corresponded to increased variability. In postmenopausal women, was similar regardless of fibroglandular content. Contributions from collagen and glands to were independent and equivalent in benign sites; glands showed a stronger positive correlation than collagen to in malignant sites. Our data suggest that scattering could differentiate highly scattering malignant from benign tissues in postmenopausal women. The relationship between scattering and tissue composition will support improved scattering models and technologies to enhance intraoperative optical margin assessment.

  18. Improved optical mass tracer for galaxy clusters calibrated using weak lensing measurements

    CERN Document Server

    Reyes, Reinabelle; Hirata, Christopher M; Bahcall, Neta; Seljak, Uros

    2008-01-01

    We develop an improved mass tracer for clusters of galaxies from optically observed parameters, and calibrate the mass relation using weak gravitational lensing measurements. We employ a sample of ~ 13,000 optically-selected clusters from the Sloan Digital Sky Survey (SDSS) maxBCG catalog, with photometric redshifts in the range 0.1-0.3. The optical tracers we consider are cluster richness, cluster luminosity, luminosity of the brightest cluster galaxy (BCG), and combinations of these parameters. We measure the weak lensing signal around stacked clusters as a function of the different tracers, and use it to determine the tracer with the least amount of scatter. We further use the weak lensing data to calibrate the mass normalization. We find that the best mass estimator for massive clusters is a combination of cluster richness, N_{200}, and the luminosity of the brightest cluster galaxy, L_{BCG}: M_{200\\bar{\\rho}} = (1.27 +/- 0.08) (N_{200}/20)^{1.20 +/- 0.09} (L_{BCG}/\\bar{L}_{BCG}(N_{200}))^{0.71 +/- 0.14} ...

  19. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  20. Diode Laser 810 Nm as a Potential Treatment to Improve Visual Function in Nonarteritic Anterior Ischemic Optic Neuropathy (NAION

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Heidari

    2011-01-01

    Full Text Available Nonarteritic anterior ischemic optic neuropathy (NAION is one of the most widespread visually disabling diseases in the middle-aged and elderly population. The optic nerve damage appears to result from a perfusion insufficiency in the short posterior ciliary arteries leading to infarction of the retrolaminar portion of the optic disc. Induced Heat shock protein (Hsp is known to have neuroprotective effects against ischemic injury of the central nervous system in mammals. Transpupillary thermotherapy (TTT application to the optic nerve head induces Hsp70 expression. We hypothesize that Transpupillary thermotherapy (TTT could be a novel method for improving and preserving the function of the optic nerve fibers in the eye with NAION. An 810-nm diode laser beam is focused to the center of the optic nerve head to induce Hsp. Controlled prospective and randomized clinical trial is necessary to confirm conclusively the effectiveness of this method.

  1. Optical gratings and grisms: developments on straylight and polarization sensitivity improved microstructures

    Science.gov (United States)

    Diehl, Torsten; Triebel, Peter; Moeller, Tobias; Gatto, Alexandre; Pesch, Alexander; Erdmann, Lars H.; Burkhardt, Matthias; Kalies, Alexander

    2015-09-01

    Spectral imaging systems lead to enhanced sensing properties when the sensing system provides sufficient spectral resolution to identify materials from its spectral reflectance signature. The performance of diffraction gratings provides an initial way to improve instrumental resolution. Thus, subsequent manufacturing techniques of high quality gratings are essential to significantly improve the spectral performance. The ZEISS unique technology of manufacturing real-blazed profiles comprising transparent substrates is well suited for the production of transmission gratings. In order to reduce high order aberrations, aspherical and free-form surfaces can be alternatively processed to allow more degrees of freedom in the optical design of spectroscopic instruments with less optical elements and therefore size and weight advantages. Prism substrates were used to manufacture monolithic GRISM elements for UV to IR spectral range. Many years of expertise in the research and development of optical coatings enable high transmission anti-reflection coatings from the DUV to the NIR. ZEISS has developed specially adapted coating processes (Ion beam sputtering, ion-assisted deposition and so on) for maintaining the micro-structure of blazed gratings in particular. Besides of transmission gratings, numerous spectrometer setups (e.g. Offner, Rowland circle, Czerny-Turner system layout) working on the optical design principles of reflection gratings. This technology steps can be applied to manufacture high quality reflection gratings from the EUV to the IR applications with an outstanding level of low stray light and ghost diffraction order by employing a combination of holography and reactive ion beam etching together with the in-house coating capabilities. We report on results of transmission, reflection gratings on plane and curved substrates and GRISM elements with enhanced efficiency of the grating itself combined with low scattered light in the angular distribution. Focusing

  2. Using Pre-TMIn Treatment to Improve the Optical Properties of Green Light Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Bing Xu

    2014-01-01

    Full Text Available We investigated the effects of pre-TMIn treatment on the optical properties of green light emitting diodes (LEDs. Although pre-TMIn treatment did not affect the epitaxial structure of quantum wells, it significantly improved the quality of the surface morphology relative to that of the untreated sample. Indium cluster can be seen by high-resolution transmission electron microscopy (HR-TEM, which is the explanation for the red-shift of photoluminescence (PL. Time-resolved photoluminescence measurements indicated that the sample prepared with pre-TMIn treatment had a shorter radiative decay time. As a result, the light output power of the treated green LED was higher than that of the conventional untreated one. Thus, pre-TMIn treatment appears to be a simple and efficient means of improving the performance of green LEDs.

  3. Spatial-Resolution Improvement in Optical Frequency Domain Reflectometry System Based on Tunable Linear Fiber Laser

    Energy Technology Data Exchange (ETDEWEB)

    Li Guoyu; Li Yan [Institute of Information Engineering, Handan College, Handan, 056005 (China); Zhao Peng, E-mail: guoyu_li@yahoo.cn [School of Physics and Optoelectronic Engineering, Dalian University of Technology, Dalian 116024 (China)

    2011-02-01

    In optical frequency domain reflectometry (OFDR) system, the spatial resolution is obtained by using the total frequency-sweep span of the tunable laser. However, in practice, the spatial resolution is severely limited by nonlinearity in the lightwave-frequency sweep of the tunable laser. A closed-loop PZT modulated DBR linear fiber laser is proposed to improve the spatial resolution of the OFDR system. Experimental results show that the spatial resolution of OFDR system has improved greatly. When the frequency sweep excursion is 66GHz and the fiber under test (FUT) is 7 m, the OFDR system has a spatial resolution of 1.5 m with open-loop PZT modulated laser. But the spatial resolution increases to 35 cm with closed-loop PZT modulated laser.

  4. Incoherent structured illumination improves optical sectioning and contrast in multiphoton super-resolution microscopy.

    Science.gov (United States)

    Winter, Peter W; Chandris, Panagiotis; Fischer, Robert S; Wu, Yicong; Waterman, Clare M; Shroff, Hari

    2015-02-23

    Three-dimensional super-resolution imaging in thick, semi-transparent biological specimens is hindered by light scattering, which increases background and degrades both contrast and optical sectioning. We describe a simple method that mitigates these issues, improving image quality in our recently developed two-photon instant structured illumination microscope without requiring any hardware modifications to the instrument. By exciting the specimen with three laterally-structured, phase-shifted illumination patterns and post-processing the resulting images, we digitally remove both scattered and out-of-focus emissions that would otherwise contaminate our raw data. We demonstrate the improved performance of our approach in biological samples, including pollen grains, primary mouse aortic endothelial cells cultured in a three-dimensional collagen matrix and live tumor-like cell spheroids.

  5. Design and Evaluation of 10-Gbps Inter-satellite Optical Wireless Communication Link for Improved Performance

    Science.gov (United States)

    Gupta, Amit; Nagpal, Shaina

    2017-05-01

    Inter-satellite optical wireless communication (IsOWC) systems can be chosen over existing microwave satellite systems for deploying in space in the future due to their high bandwidth, small size, light weight, low power and low cost. However, the IsOWC system suffers from various attenuations due to weather conditions, turbulence or scintillations which limit its performance and decreases its availability. So, in order to improve the performance, IsOWC system using directly modulated laser source is proposed in this work. The system is designed and evaluated to be suitable for high data rate transmissions up to 10 Gbps. The performance of the system is investigated in order to reduce the cost and complexity of link and improving the quality of information signal. Further the proposed IsOWC system is analysed using BER analyser, power meter and oscilloscope Visualizer.

  6. A short contemporary history of disseminated intravascular coagulation.

    Science.gov (United States)

    Levi, Marcel; van der Poll, Tom

    2014-11-01

    Disseminated intravascular coagulation (DIC) is a syndrome characterized by systemic intravascular activation of coagulation, leading to a widespread deposition of fibrin in the circulation. There is ample experimental and pathological evidence that the fibrin deposition contributes to multiple organ failure. The massive and ongoing activation of coagulation may result in depletion of platelets and coagulation factors, which may cause bleeding (consumption coagulopathy). The syndrome of DIC is well known in the medical literature for centuries, although a more precise description of the underlying mechanisms had to await the 20th century. Initial ideas on a role of the contact activation system as the primary trigger for the systemic activation of coagulation as well as a presumed hyperfibrinolytic response in DIC have been found to be misconceptions. Experimental and clinical evidence now indicate that the initiation of coagulation in DIC is caused by tissue factor expression, which in combination with downregulated physiological anticoagulant pathways and impaired fibrinolysis leads to widespread fibrin deposition. In addition, an extensive bidirectional interaction between coagulation and inflammation may further contribute to the pathogenesis of DIC.

  7. Focused intravascular ultrasonic probe using dimpled transducer elements.

    Science.gov (United States)

    Chen, Y; Qiu, W B; Lam, K H; Liu, B Q; Jiang, X P; Zheng, H R; Luo, H S; Chan, H L W; Dai, J Y

    2015-02-01

    High-frequency focused intravascular ultrasonic probes were fabricated in this study using dimple technique based on PMN-PT single crystal and lead-free KNN-KBT-Mn ceramic. The center frequency, bandwidth, and insertion loss of the PMN-PT transducer were 34 MHz, 75%, and 22.9 dB, respectively. For the lead-free probe, the center frequency, bandwidth, and insertion loss were found to be 40 MHz, 72%, and 28.8 dB, respectively. The ultrasonic images of wire phantom and vessels with good resolution were obtained to evaluate the transducer performance. The -6 dB axial and lateral resolutions of the PMN-PT probe were determined to be 58 μm and 131 μm, respectively. For the lead-free probe, the axial and lateral resolutions were found to be 44 μm and 125 μm, respectively. These results suggest that the mechanical dimpling technique has good potential in preparing focused transducers for intravascular ultrasound applications.

  8. [Disseminated intravascular coagulation. Case series and literature review].

    Science.gov (United States)

    Del Carpio-Orantes, Luis; García-Ortiz, Jorge José

    2014-01-01

    INTRODUCCIÓN: la coagulación intravascular diseminada es una entidad caracteriza por activación de la cascada de la coagulación y fibrinólisis endógena, que puede provocar la muerte. Nuestros objetivos fueron identificar la incidencia de coagulación intravascular diseminada, sus agentes etiológicos y la correlación entre la puntuación de la escala Apache II y la propuesta por la Sociedad Internacional de Trombosis y Hemostasia para el diagnóstico de esta entidad. MÉTODOS: estudio retrospectivo, observacional y descriptivo de pacientes atendidos en una unidad de cuidados intensivos en un periodo de 17 meses. Se analizó etiología, edad, sexo, conteo de plaquetas, coagulograma, niveles de fibrinógeno sérico y cuantificación del dímero D. Se calculó la puntuación de la escala propuesta por la Sociedad Internacional de Trombosis y Hemostasia y de la escala APACHE II.

  9. Experience With Intravascular Ultrasound Imaging Of Human Atherosclerotic Arteries

    Science.gov (United States)

    Mallery, John A.; Gessert, James M.; Maciel, Mario; Tobis, John M.; Griffith, James M.; Berns, Michael W.; Henry, Walter L.

    1989-08-01

    Normal human arteries have a well-defined structure on intravascular images. The intima appears very thin and is most likely represented by a bright reflection arising from the internal elastic lamina. The smooth muscle tunica media is echo-lucent on the ultrasound image and appears as a dark band separating the intima from the adventitia. The adventitia is a brightly reflective layer of variable thickness. The thickness of the intima, and therefore of the atherosclerotic plaque can be accurately measured from the ultrasound images and correlates well with histology. Calcification within the wall of arteries is seen as bright echo reflection with shadowing of the peripheral wall. Fibrotic regions are highly reflective but do not shadow. Necrotic liquid regions within advanced atherosclerotic plaques are seen on ultrasound images as large lucent zones surrounded by echogenic tissue. Imaging can be performed before and after interventional procedures, such as laser angioplasty, balloon angioplasty and atherectomy. Intravascular ultrasound appears to provide an imaging modality for identifying the histologic characteristics of diseased arteries and for quantifying plaque thickness. It might be possible to perform such quantification to evaluate the results of interventional procedures.

  10. An Implantable Intravascular Pressure Sensor for a Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Luigi Brancato

    2016-08-01

    Full Text Available The aim of this study is to investigate the intravascular application of a micro-electro-mechanical system (MEMS pressure sensor to directly measure the hemodynamic characteristics of a ventricular assist device (VAD. A bio- and hemo-compatible packaging strategy is implemented, based on a ceramic thick film process. A commercial sub-millimeter piezoresistive sensor is attached to an alumina substrate, and a double coating of polydimethylsiloxane (PDMS and parylene-C is applied. The final size of the packaged device is 2.6 mm by 3.6 mm by 1.8 mm. A prototype electronic circuit for conditioning and read-out of the pressure signal is developed, satisfying the VAD-specific requirements of low power consumption (less than 14.5 mW in continuous mode and small form factor. The packaged sensor has been submitted to extensive in vitro tests. The device displayed a temperature-independent sensitivity (12 μ V/V/mmHg and good in vitro stability when exposed to the continuous flow of saline solution (less than 0.05 mmHg/day drift after 50 h. During in vivo validation, the transducer has been successfully used to record the arterial pressure waveform of a female sheep. A small, intravascular sensor to continuously register the blood pressure at the inflow and the outflow of a VAD is developed and successfully validated in vivo.

  11. Thyroid Storm Complicated by Bicytopenia and Disseminated Intravascular Coagulation

    Science.gov (United States)

    Tokushima, Yoshinori; Sakanishi, Yuta; Nagae, Kou; Tokushima, Midori; Tago, Masaki; Tomonaga, Motosuke; Yoshioka, Tsuneaki; Hyakutake, Masaki; Sugioka, Takashi; Yamashita, Shu-ichi

    2014-01-01

    Patient: Male, 23 Final Diagnosis: Thyroid storm Symptoms: Delirium • diarrhea • fever • hypertension • hyperventilation • tachycardia • weight loss Medication: — Clinical Procedure: — Specialty: Endocrinology and Metabolic Objective: Unusual clinical course Background: The clinical presentation of thyroid storm includes fever, tachycardia, hypertension, and neurological abnormalities. It is a serious condition with a high mortality rate. Furthermore, some other complications affect the clinical course of thyroid storm. Although it is reported that prognosis is poor when thyroid storm is complicated by disseminated intravascular coagulation syndrome (DIC) and leukopenia, reports of such cases are rare. Case Report: A 23-year-old man presented with delirium, high pyrexia, diarrhea, and weight loss of 18 kg over 2 months. According to the criteria of Burch and Wartofsky, he was diagnosed with thyroid storm on the basis of his symptom-complex and laboratory data that confirmed the presence of hyperthyroidism. Investigations also found leukopenia, thrombocytopenia, and disseminated intravascular coagulation, all of which are very rare complications of thyroid storm. We successfully treated him with combined therapy including anti-thyroid medication, despite leukopenia. Conclusions: Early diagnosis and treatment are essential in ensuring a good outcome for patients with this rare combination of medical problems. PMID:25072662

  12. An improved least cost routing approach for WDM optical network without wavelength converters

    Science.gov (United States)

    Bonani, Luiz H.; Forghani-elahabad, Majid

    2016-12-01

    Routing and wavelength assignment (RWA) problem has been an attractive problem in optical networks, and consequently several algorithms have been proposed in the literature to solve this problem. The most known techniques for the dynamic routing subproblem are fixed routing, fixed-alternate routing, and adaptive routing methods. The first one leads to a high blocking probability (BP) and the last one includes a high computational complexity and requires immense backing from the control and management protocols. The second one suggests a trade-off between performance and complexity, and hence we consider it to improve in our work. In fact, considering the RWA problem in a wavelength routed optical network with no wavelength converter, an improved technique is proposed for the routing subproblem in order to decrease the BP of the network. Based on fixed-alternate approach, the first k shortest paths (SPs) between each node pair is determined. We then rearrange the SPs according to a newly defined cost for the links and paths. Upon arriving a connection request, the sorted paths are consecutively checked for an available wavelength according to the most-used technique. We implement our proposed algorithm and the least-hop fixed-alternate algorithm to show how the rearrangement of SPs contributes to a lower BP in the network. The numerical results demonstrate the efficiency of our proposed algorithm in comparison with the others, considering different number of available wavelengths.

  13. Improved Excitation Light Rejection Enhances Small-Animal Fluorescent Optical Imaging

    Directory of Open Access Journals (Sweden)

    Kildong Hwang

    2005-07-01

    Full Text Available Small-animal fluorescence-enhanced imaging involves the detection of weak fluorescent signals emanating from nanomolar to picomolar concentrations of exogenous or endogenously produced fluorophore concurrent with the rejection of an overwhelmingly large component of backscattered excitation light. The elimination of the back-reflected excitation light of the collected signal remains a major and often unrecognized challenge for further reducing the noise floor and increasing sensitivity of small-animal fluorescence imaging. Herein, we show that the combination of three-cavity interference and holographic super notch filters with appropriate imaging lenses to collimate light improves rejection of excitation light, enabling more accurate imaging. To assess excitation leakage, the “out-of-band (S(Λx” to “in-band (S(Λm–S(Λx” signal ratio from phantom studies and the target-to-background ratio (TBR from in vivo animal imaging was acquired with and without collimating optics. The addition of collimating optics resulted in a 51% to 75% reduction in the ratio of (S(Λx/(S(Λm–S(Λx for the phantom studies and an improvement of TBR from 11% to 31% and of signal-to-noise ratio from 11% to 142% for an integrin-targeting conjugate in human glioma xenografts.

  14. The optical synthetic aperture image restoration based on the improved maximum-likelihood algorithm

    Science.gov (United States)

    Geng, Zexun; Xu, Qing; Zhang, Baoming; Gong, Zhihui

    2012-09-01

    Optical synthetic aperture imaging (OSAI) can be envisaged in the future for improving the image resolution from high altitude orbits. Several future projects are based on optical synthetic aperture for science or earth observation. Comparing with equivalent monolithic telescopes, however, the partly filled aperture of OSAI induces the attenuation of the modulation transfer function of the system. Consequently, images acquired by OSAI instrument have to be post-processed to restore ones equivalent in resolution to that of a single filled aperture. The maximum-likelihood (ML) algorithm proposed by Benvenuto performed better than traditional Wiener filter did, but it didn't work stably and the point spread function (PSF), was assumed to be known and unchanged in iterative restoration. In fact, the PSF is unknown in most cases, and its estimation was expected to be updated alternatively in optimization. Facing these limitations of this method, an improved ML (IML) reconstruction algorithm was proposed in this paper, which incorporated PSF estimation by means of parameter identification into ML, and updated the PSF successively during iteration. Accordingly, the IML algorithm converged stably and reached better results. Experiment results showed that the proposed algorithm performed much better than ML did in peak signal to noise ratio, mean square error and the average contrast evaluation indexes.

  15. INTERNATIONAL SOCIETY ON THROMBOSIS AND HAEMOSTASIS DISSEMINATED INTRAVASCULAR COAGULATION SCORING SYSTEM: IS IT A GOOD PROGNOSTIC INDICATOR IN DIC

    Directory of Open Access Journals (Sweden)

    Nisal Amit, Nimbargi Ravindra, Shelke Parineeta, Kelkar Anjali

    2015-07-01

    Full Text Available Background: Disseminated intravascular coagulation is an acquired disorder characterized by intravascular activation of coagulation due to variety of causes. There is excessive thrombin formation leading to fibrin deposition in microcirculation and consequent ischemic organ damage. The diagnosis is essentially clinical supported by laboratory parameters and a scoring system based on these. The mainstay of treatment is correction of underlying cause and haemostatic support with replacement of coagulation factors. Aim: To evaluate the use of ISTH DIC scoring system in patients of clinically suspected Disseminated Intravascular Coagulation. Methods: 60 cases were studied over a period of one year. Patients were selected with a clinical suspicion of DIC who are having an underlying predisposing condition. Clinical signs and symptoms were recorded. Routine investigations and the tests necessary to calculate the ISTH score i.e. platelet count, Prothrombin time; D-dimer and Fibrinogen were done. The scoring criteria of ISTH were applied in these cases. Chi square and Fisher’s exact tests were used for analysis of the data. Results: The commonest cause of the underlying disorder in our study was found to be Sepsis (66.7% followed by trauma (10%, obstetric causes (8.3% and solid malignancy (6.7%. There was a significant association of ISTH score with outcome of the patients (P value <0.05. Raised APTT and presence of schistocytes also had a significant association with a high ISTH score. Conclusion: ISTH DIC scoring criteria more precisely define clinical and laboratory parameters of DIC. Its clinical utility will improve the timely diagnosis, prediction of severity and will also aid in improving prognosis of DIC patients.

  16. Improved optical limiting performance of laser-ablation-generated metal nanoparticles due to silica-microsphere-induced local field enhancement.

    Science.gov (United States)

    Du, Zheren; Chen, Lianwei; Kao, Tsung-Sheng; Wu, Mengxue; Hong, Minghui

    2015-01-01

    For practical application, optical limiting materials must exhibit a fast response and a low threshold in order to be used for the protection of the human eye and electro-optical sensors against intense light. Many nanomaterials have been found to exhibit optical limiting properties. Laser ablation offers the possibility of fabricating nanoparticles from a wide range of target materials. For practical use of these materials, their optical limiting performance, including optical limiting threshold and the ability to efficiently attenuate high intensity light, needs to be improved. In this paper, we fabricate nanoparticles of different metals by laser ablation in liquid. We study the optical nonlinear properties of the laser-generated nanoparticle dispersion. Silica microspheres are used to enhance the optical limiting performance of the nanoparticle dispersion. The change in the optical nonlinear properties of the laser-generated nanoparticle dispersion caused by silica microspheres is studied. It is found that the incident laser beam is locally focused by the microspheres, leading to an increased optical nonlinearity of the nanoparticle dispersion.

  17. Improved optical limiting performance of laser-ablation-generated metal nanoparticles due to silica-microsphere-induced local field enhancement

    Directory of Open Access Journals (Sweden)

    Zheren Du

    2015-05-01

    Full Text Available For practical application, optical limiting materials must exhibit a fast response and a low threshold in order to be used for the protection of the human eye and electro-optical sensors against intense light. Many nanomaterials have been found to exhibit optical limiting properties. Laser ablation offers the possibility of fabricating nanoparticles from a wide range of target materials. For practical use of these materials, their optical limiting performance, including optical limiting threshold and the ability to efficiently attenuate high intensity light, needs to be improved. In this paper, we fabricate nanoparticles of different metals by laser ablation in liquid. We study the optical nonlinear properties of the laser-generated nanoparticle dispersion. Silica microspheres are used to enhance the optical limiting performance of the nanoparticle dispersion. The change in the optical nonlinear properties of the laser-generated nanoparticle dispersion caused by silica microspheres is studied. It is found that the incident laser beam is locally focused by the microspheres, leading to an increased optical nonlinearity of the nanoparticle dispersion.

  18. Error analysis and algorithm implementation for an improved optical-electric tracking device based on MEMS

    Science.gov (United States)

    Sun, Hong; Wu, Qian-zhong

    2013-09-01

    In order to improve the precision of optical-electric tracking device, proposing a kind of improved optical-electric tracking device based on MEMS, in allusion to the tracking error of gyroscope senor and the random drift, According to the principles of time series analysis of random sequence, establish AR model of gyro random error based on Kalman filter algorithm, then the output signals of gyro are multiple filtered with Kalman filter. And use ARM as micro controller servo motor is controlled by fuzzy PID full closed loop control algorithm, and add advanced correction and feed-forward links to improve response lag of angle input, Free-forward can make output perfectly follow input. The function of lead compensation link is to shorten the response of input signals, so as to reduce errors. Use the wireless video monitor module and remote monitoring software (Visual Basic 6.0) to monitor servo motor state in real time, the video monitor module gathers video signals, and the wireless video module will sent these signals to upper computer, so that show the motor running state in the window of Visual Basic 6.0. At the same time, take a detailed analysis to the main error source. Through the quantitative analysis of the errors from bandwidth and gyro sensor, it makes the proportion of each error in the whole error more intuitive, consequently, decrease the error of the system. Through the simulation and experiment results shows the system has good following characteristic, and it is very valuable for engineering application.

  19. Chemically-doped graphene with improved surface plasmon characteristics: an optical near-field study.

    Science.gov (United States)

    Zheng, Zebo; Wang, Weiliang; Ma, Teng; Deng, Zexiang; Ke, Yanlin; Zhan, Runze; Zou, Qionghui; Ren, Wencai; Chen, Jun; She, Juncong; Zhang, Yu; Liu, Fei; Chen, Huanjun; Deng, Shaozhi; Xu, Ningsheng

    2016-10-01

    One of the most fascinating and important merits of graphene plasmonics is their tunability over a wide range. While chemical doping has proven to be a facile and effective way to create graphene plasmons, most of the previous studies focused on the macroscopic behaviors of the plasmons in chemically-doped graphene and little was known about their nanoscale responses and related mechanisms. Here, to the best of our knowledge, we present the first experimental near-field optical study on chemically-doped graphene with improved surface plasmon characteristics. By using a scattering-type scanning near-field optical microscope (s-SNOM), we managed to show that the graphene plasmons can be tuned and improved using a facile chemical doping method. Specifically, the plasmon interference patterns near the edge of the monolayer graphene were substantially enhanced via nitric acid (HNO3) exposure. The plasmon-related characteristics can be deduced by analyzing such plasmonic fringes, which exhibited a longer plasmon wavelength and reduced plasmon damping rate. In addition, the local carrier density and therefore the Fermi energy level (EF) of graphene can be obtained from the plasmonic nano-imaging, which indicated that the enhanced plasmon oscillation originated from the injection of free holes into graphene by HNO3. These findings were further corroborated by theoretical calculations using density functional theory (DFT). We believe that our findings provide a clear nanoscale picture on improving graphene plasmonics by chemical doping, which will be helpful for optimizing graphene plasmonics and for elucidating the mechanisms of two-dimensional light confinement by atomically thick materials.

  20. Highly curved image sensors: a practical approach for improved optical performance

    Science.gov (United States)

    Guenter, Brian; Joshi, Neel; Stoakley, Richard; Keefe, Andrew; Geary, Kevin; Freeman, Ryan; Hundley, Jake; Patterson, Pamela; Hammon, David; Herrera, Guillermo; Sherman, Elena; Nowak, Andrew; Schubert, Randall; Brewer, Peter; Yang, Louis; Mott, Russell; McKnight, Geoff

    2017-06-01

    The significant optical and size benefits of using a curved focal surface for imaging systems have been well studied yet never brought to market for lack of a high-quality, mass-producible, curved image sensor. In this work we demonstrate that commercial silicon CMOS image sensors can be thinned and formed into accurate, highly curved optical surfaces with undiminished functionality. Our key development is a pneumatic forming process that avoids rigid mechanical constraints and suppresses wrinkling instabilities. A combination of forming-mold design, pressure membrane elastic properties, and controlled friction forces enables us to gradually contact the die at the corners and smoothly press the sensor into a spherical shape. Allowing the die to slide into the concave target shape enables a threefold increase in the spherical curvature over prior approaches having mechanical constraints that resist deformation, and create a high-stress, stretch-dominated state. Our process creates a bridge between the high precision and low-cost but planar CMOS process, and ideal non-planar component shapes such as spherical imagers for improved optical systems. We demonstrate these curved sensors in prototype cameras with custom lenses, measuring exceptional resolution of 3220 line-widths per picture height at an aperture of f/1.2 and nearly 100% relative illumination across the field. Though we use a 1/2.3" format image sensor in this report, we also show this process is generally compatible with many state of the art imaging sensor formats. By example, we report photogrammetry test data for an APS-C sized silicon die formed to a 30$^\\circ$ subtended spherical angle. These gains in sharpness and relative illumination enable a new generation of ultra-high performance, manufacturable, digital imaging systems for scientific, industrial, and artistic use.

  1. Controlling laser beam irradiation area using an optical duplicate system to improve satellite-ground laser communications

    Science.gov (United States)

    Nakayama, Tomoko; Takayama, Yoshihisa; Fujikawa, Chiemi; Kodate, Kashiko

    2016-08-01

    To improve the quality of ground to satellite laser communications, we propose an optical duplicate system of the optical ground station. Our proposed approach can be used to control the beam irradiation area for a satellite position without changing the total power of the output beam and the mechanical drive unit; this is performed by controlling the input pattern of a liquid crystal filter inserted in the input plane of the optical duplicate system. Most of the power of the diffracted laser beam emitted from the ground is focused on the optical axis. By distributing the power to side lobes, it is possible to extend the coverage area for a satellite position. This system allows the laser beam irradiation area to be controlled by a sufficient degree by adjusting the threshold of the satellite reception level. We verify the efficacy of the system using wave optics numerical calculations.

  2. Quantum information tapping using a fiber optical parametric amplifier with noise figure improved by correlated inputs.

    Science.gov (United States)

    Guo, Xueshi; Li, Xiaoying; Liu, Nannan; Ou, Z Y

    2016-07-26

    One of the important functions in a communication network is the distribution of information. It is not a problem to accomplish this in a classical system since classical information can be copied at will. However, challenges arise in quantum system because extra quantum noise is often added when the information content of a quantum state is distributed to various users. Here, we experimentally demonstrate a quantum information tap by using a fiber optical parametric amplifier (FOPA) with correlated inputs, whose noise is reduced by the destructive quantum interference through quantum entanglement between the signal and the idler input fields. By measuring the noise figure of the FOPA and comparing with a regular FOPA, we observe an improvement of 0.7 ± 0.1 dB and 0.84 ± 0.09 dB from the signal and idler outputs, respectively. When the low noise FOPA functions as an information splitter, the device has a total information transfer coefficient of Ts+Ti = 1.5 ± 0.2, which is greater than the classical limit of 1. Moreover, this fiber based device works at the 1550 nm telecom band, so it is compatible with the current fiber-optical network for quantum information distribution.

  3. Combination of principal component analysis and optical-flow motion compensation for improved cardiac MR thermometry

    Science.gov (United States)

    Toupin, S.; de Senneville, B. Denis; Ozenne, V.; Bour, P.; Lepetit-Coiffe, M.; Boissenin, M.; Jais, P.; Quesson, B.

    2017-02-01

    The use of magnetic resonance (MR) thermometry for the monitoring of thermal ablation is rapidly expanding. However, this technique remains challenging for the monitoring of the treatment of cardiac arrhythmia by radiofrequency ablation due to the heart displacement with respiration and contraction. Recent studies have addressed this problem by compensating in-plane motion in real-time with optical-flow based tracking technique. However, these algorithms are sensitive to local variation of signal intensity on magnitude images associated with tissue heating. In this study, an optical-flow algorithm was combined with a principal component analysis method to reduce the impact of such effects. The proposed method was integrated to a fully automatic cardiac MR thermometry pipeline, compatible with a future clinical workflow. It was evaluated on nine healthy volunteers under free breathing conditions, on a phantom and in vivo on the left ventricle of a sheep. The results showed that local intensity changes in magnitude images had lower impact on motion estimation with the proposed method. Using this strategy, the temperature mapping accuracy was significantly improved.

  4. Quantum information tapping using a fiber optical parametric amplifier with noise figure improved by correlated inputs

    Science.gov (United States)

    Guo, Xueshi; Li, Xiaoying; Liu, Nannan; Ou, Z. Y.

    2016-07-01

    One of the important functions in a communication network is the distribution of information. It is not a problem to accomplish this in a classical system since classical information can be copied at will. However, challenges arise in quantum system because extra quantum noise is often added when the information content of a quantum state is distributed to various users. Here, we experimentally demonstrate a quantum information tap by using a fiber optical parametric amplifier (FOPA) with correlated inputs, whose noise is reduced by the destructive quantum interference through quantum entanglement between the signal and the idler input fields. By measuring the noise figure of the FOPA and comparing with a regular FOPA, we observe an improvement of 0.7 ± 0.1 dB and 0.84 ± 0.09 dB from the signal and idler outputs, respectively. When the low noise FOPA functions as an information splitter, the device has a total information transfer coefficient of Ts+Ti = 1.5 ± 0.2, which is greater than the classical limit of 1. Moreover, this fiber based device works at the 1550 nm telecom band, so it is compatible with the current fiber-optical network for quantum information distribution.

  5. Improvement of Optical Reactivity for Nano-TiO2 Film by Nitrogen ECR Plasma

    Institute of Scientific and Technical Information of China (English)

    Yuying XIONG; Tao MA; Linghong KONG; Junfang CHEN; Xianqiu WU; Honghua YU; Zhenxi ZHANG

    2006-01-01

    Nitrogen ion was implanted into the nano-TiO2 film surfaces by electron cyclotron resonance (ECR) plasma modification to improve the optical reactivity in visible-light region for nano-TiO2. Diagnosing the N2 plasma by optical emission spectroscopy (OES) was applied to the process of plasma modification. X-ray photoelectron spectroscopy (XPS) was used for analysis of the binding of element after plasma modification. It is shown that the surface modification was caused by excitated N. The injecting of N2 and N2+ leads to the increase in the dissociative interstitial state N in the films. The doped N makes for TiO2-xNx appearing in the TiO2films. TiO2-xNx forms the impurity energy state in the TiO2 energy band gap and reduces the energy band gap. This is the main reason leading to the red shift of absorption edge.

  6. Improvement of the chirality near avoided resonance crossing in optical microcavity

    Institute of Scientific and Technical Information of China (English)

    SONGQingHai[1,2; GUZhiYuan[1; ZHANGNan[1; WANGKaiYang[1; YINingBo[1; XIAOShuMin[1

    2015-01-01

    Chirality is one of the important phenomena at the vicinity of exceptional point (EP). The conventional understanding is that the chirality is determined by asymmetrical scattering efficiency (η), which reaches to zero only when the resonance ap- proaches EP. Here we study the possibility to enhance the chirality in open systems with a more robust mechanism. By com- bining chirality with avoided resonance crossing, we show that the chirality and 7 can be dramatically modified. Taking a spi- ral shaped annular cavity as an example, we show that the chirality of optical resonances can be significantly improved when two sets of chiral states approach each other, The imbalance between counterclockwise (CCW) components and clockwise (CW) components has been enhanced by more than an order of magnitude. Our research provides a new route to tailor and control the chirality in open systems.

  7. Improving the light quantification of near infrared (NIR) diffused light optical tomography with ultrasound localization

    Science.gov (United States)

    Ardeshirpour, Yasaman

    According to the statistics published by the American Cancer Society, currently breast cancer is the second most common cancer after skin cancer and the second cause of cancer death after lung cancer in the female population. Diffuse optical tomography (DOT) using near-infrared (NIR) light, guided by ultrasound localization, has shown great promise in distinguishing benign from malignant breast tumors and in assessing the response of breast cancer to chemotherapy. Our ultrasound-guided DOT system is based on reflection geometry, with patients scanned in supine position using a hand-held probe. For patients with chest-wall located at a depth shallower than 1 to 2cm, as in about 10% of our clinical cases, the semi-infinite imaging medium is not a valid assumption and the chest-wall effect needs to be considered in the imaging reconstruction procedure. In this dissertation, co-registered ultrasound images were used to model the breast-tissue and chest-wall as a two-layer medium. The effect of the chest wall on breast lesion reconstruction was systematically investigated. The performance of the two-layer model-based reconstruction, using the Finite Element Method, was evaluated by simulation, phantom experiments and clinical studies. The results show that the two-layer model can improve the accuracy of estimated background optical properties, the reconstructed absorption map and the total hemoglobin concentration of the lesion. For patients' data affected by chest wall, the perturbation, which is the difference between measurements obtained at lesion and normal reference sites, may include the information of background mismatch between these two sites. Because the imaging reconstruction is based on the perturbation approach, the effect of this mismatch between the optical properties at the two sites on reconstructed optical absorption was studied and a guideline for imaging procedure was developed to reduce these effects during data capturing. To reduce the artifacts

  8. Co-doping of Ag into Mn:ZnSe Quantum Dots: Giving Optical Filtering effect with Improved Monochromaticity

    OpenAIRE

    Zhiyang Hu; Shuhong Xu; Xiaojing Xu; Zhaochong Wang; Zhuyuan Wang; Chunlei Wang; Yiping Cui

    2015-01-01

    In optics, when polychromatic light is filtered by an optical filter, the monochromaticity of the light can be improved. In this work, we reported that Ag dopant atoms could be used as an optical filter for nanosized Mn:ZnSe quantum dots (QDs). If no Ag doping, aqueous Mn:ZnSe QDs have low monochromaticity due to coexisting of strong ZnSe band gap emission, ZnSe trap emission, and Mn dopant emission. After doping of Ag into QDs, ZnSe band gap and ZnSe trap emissions can be filtered, leaving o...

  9. [Traumatic abruption of the placenta with disseminated intravascular coagulation].

    Science.gov (United States)

    Benz, R; Malär, A-U; Benz-Wörner, J; Scherer, M; Hodel, M; Gähler, A; Haberthür, C; Konrad, C

    2012-10-01

    Trauma in pregnancy is infrequent and a systematic primary strategy constitutes a real challenge for the interdisciplinary team. With a high fetal mortality rate and a substantial maternal mortality rate traumatic placental abruption is a severe emergency which every anesthetist should be aware of. After hemodynamic stabilization of the mother and control of the viability of the fetus the therapy of traumatic placental abruption consists mostly of an immediate caesarean section. Coagulopathy by depletion of coagulation factors as well as disseminated intravascular coagulation (DIC) have to be expected and consequently a massive blood loss must be anticipated. Thrombelastography provides assistance for fast differential diagnosis and goal-directed treatment of the disturbed sections of the coagulation cascade.

  10. Disseminated intravascular coagulation in obstetric and gynecologic disorders.

    Science.gov (United States)

    Montagnana, Martina; Franchi, Massimo; Danese, Elisa; Gotsch, Francesca; Guidi, Gian Cesare

    2010-06-01

    Disseminated intravascular coagulation (DIC) is a syndrome characterized by a massive, widespread, and ongoing activation of the coagulation system, secondary to a variety of clinical conditions. Many obstetric complications, such as abruptio placentae, amniotic fluid embolism, endotoxin sepsis, retained dead fetus, post-hemorrhagic shock, hydatidiform mole, and gynecologic malignancies, might trigger DIC. In these gynecologic and obstetric settings, DIC is usually associated with high mortality and morbidity rates. No single laboratory test is sensitive or specific enough to diagnose DIC definitively, but it can be diagnosed by using a combination of multiple clinical and laboratory tests that reflect the pathophysiology of the syndrome. At present, the therapeutical approach to pregnancy- and gynecologic-related DIC comprises the specific and aggressive treatment of the underlying disease, eventually followed by a supportive blood product replacement therapy and restoration of physiological anticoagulant pathways. This article reviews the etiopathogenesis, clinical manifestations, laboratory diagnosis, and therapy of pregnancy- and gynecologic-related DIC.

  11. Potential diagnostic markers for disseminated intravascular coagulation of sepsis.

    Science.gov (United States)

    Iba, Toshiaki; Ito, Takashi; Maruyama, Ikuro; Jilma, Bernd; Brenner, Thorsten; Müller, Marcella C A; Juffermans, Nicole P; Thachil, Jecko

    2016-03-01

    Disseminated intravascular coagulation (DIC) is an acquired thrombo-haemorrhagic disorder which arises in clinical scenarios like sepsis, trauma and malignancies. The clinic-laboratory diagnosis of DIC is made in a patient who develops the combination of laboratory abnormalities in the appropriate clinical scenario. The most common laboratory parameters in this setting have been the clotting profile, platelet count, serum fibrinogen and fibrin degradation markers. These tests had the advantage that they could be performed easily and in most laboratories. However, with the better understanding of the pathophysiology of DIC, in recent years, more specific tests have been suggested to be useful in this setting. The newer tests can also prove to be useful in prognostication in DIC. In addition, they may provide assistance in the selection and monitoring of patients diagnosed with DIC.

  12. Thrombocytopenia and thrombosis in disseminated intravascular coagulation (DIC).

    Science.gov (United States)

    Kitchens, Craig S

    2009-01-01

    Disseminated intravascular coagulation (DIC) is the physiologic result of pathologic overstimulation of the coagulation system. Despite multiple triggers, a myriad of laboratory abnormalities, and a clinical presentation ranging from gross hemostatic failure to life-threatening thrombosis, or even both simultaneously, a simplified clinical approach augmented by a few readily available tests allows prompt identification of the process and elucidation of treatment opportunities. Platelet counts in DIC may be low, especially in acute sepsis-associated DIC, yet increased in malignancy-associated chronic DIC. Thrombotic risk is not a function of the platelet count, and thrombocytopenia does not protect the patient from thrombosis. The stratification of both thrombotic risk and hemorrhagic risk will be addressed.

  13. Acute renal failure and intravascular hemolysis following henna ingestion

    Directory of Open Access Journals (Sweden)

    Hala E. A. Qurashi

    2013-01-01

    Full Text Available The powder of henna plant (Lawsonia inermis Linn. is extensively used as a decorative skin paint for nail coloring and as a hair dye. Most reports of henna toxicity have been attributed to adding a synthetic dye para-phenylenediamine (PPD. PPD is marketed as black henna added to natural henna to accentuate the dark color and shorten the application time. PPD toxicity is well known and extensively reported in medical literature. We report a case of a young Saudi male who presented with characteristic features of acute renal failure and intravascular hemolysis following ingestion of henna mixture. Management of PPD poisoning is only suppor-tive and helpful only if instituted early. Diagnosis requires a high degree of clinical suspicion, as the clinical features are quite distinctive.

  14. Basic studies on intravascular low-intensity laser therapy

    Science.gov (United States)

    Liu, Timon Cheng-Yi; Duan, Rui; Wang, Shuang-Xi; Liu, Jiang; Cui, Li-Ping; Jin, Hua; Liu, Song-Hao

    2006-09-01

    Intravascular low intensity laser therapy (ILILT) was originally put forward in USA in 1982, but popularized in Russia in 1980s and in China in 1990s, respectively. A randomized placebo-controlled study has shown ILILT clinical efficacy in patients suffering from rheumatoid arthritis. As Chinese therapeutic applications of ILILT were the most widely in the world, its basic research, such as intracellular signal transduction research, blood research in vitro, animal blood research in vivo, human blood research in vivo and traditional Chinese medicine research, was also very progressive in China. Its basic studies will be reviewed in terms of the biological information model of photobiomodulation in this paper. ILILT might work in view of its basic studies, but the further randomized placebo-controlled trial and the further safety research should be done.

  15. Advanced Congestive Heart Failure Associated With Disseminated Intravascular Coagulopathy.

    Science.gov (United States)

    Sarcon, Annahita; Liu, Xiaoli; Ton, David; Haywood, James; Hitchcock, Todd

    2015-01-01

    Background. Disseminated intravascular coagulopathy (DIC) is a complication of an underlying disease and not a primary illness. It is most commonly associated with sepsis, trauma, obstetrical complications, and malignancies. There are very few cases in the literature illustrating the association between DIC and congestive heart failure. Findings. In this report, we present a case of severe congestive heart failure, leading to biventricular thrombi and subsequently DIC. Conclusion. We suggest that the association between congestive heart failure and DIC is an underrecognized one. Congestive heart failure continues to remain a major cause of morbidity and mortality despite advances in medical therapies. Thus far, the precise role of coagulation factors in congestive heart failure is unknown. Further investigations are needed to elucidate the pathophysiology of congestive heart failure and coagulation factors.

  16. Experience with disseminated intravascular coagulation in a children's hospital

    Science.gov (United States)

    Whaun, June M.; Oski, Frank A.

    1972-01-01

    A study was initiated to determine the frequency and significance of disseminated intravascular coagulation (DIC) in the pediatric age group. With the aid of a scoring system, DIC was diagnosed in 48 patients in a period of slightly over one year in a pediatric referral centre with 7000 annual admissions. Sixty percent of all DIC occurred in infants under one month of life. Sixty-six percent of all DIC was associated with sepsis, usually from gram-negative infections. Seventy-nine percent of affected neonates were septic. Laboratory findings of diagnostic importance were anemia with red cell fragmentation, thrombocytopenia, elevated titres of fibrin split products, abnormal thrombin time, and low factor V activity. Mortality was 64% in all ages regardless of cause. Results of management of DIC by treatment of the underlying disease with or without anticoagulation were disappointing. PMID:5082021

  17. Evaluation of Disseminated Intravascular Coagulation in the Craniocerebral Traumas

    Directory of Open Access Journals (Sweden)

    Faruk Altinel

    2014-06-01

    Full Text Available Traumatic injury is one of the most important cause of disseminated intravascular coagulation (DIC. It occurs because of blood loss and hemodilution due to fluid resuscitation. The incidence of trauma associated DIC is mainly higher in the craniocerebral traumas. Even though craniocerebral trauma related DIC is well defined, the pathophysiology has been poorly characterized in the literature. Due to the fact that brain tissue is highly significant for procoagulant molecules, craniocerebral traumas are closely related to DIC. In the current study, 30 patients admitted to emergency room have been considered on the first and fifth day of admission to the hospital for the coagulation tests to evaluate DIC in both two groups. [Cukurova Med J 2014; 39(3.000: 488-495

  18. Search of intravascular hemolysis in patients with the cutaneous form of loxoscelism Pesquisa de hemólise intravascular na forma cutânea de loxoscelismo

    Directory of Open Access Journals (Sweden)

    Pasquale Morena

    1994-04-01

    Full Text Available Haptoglobin assay, a highly sensitive method to detect intravascular hemolysis was carried out in the sera of 19 patients referred to Hospital Vital Brazil with the cutaneous form of loxoscelism in order to investigate the occurrence of mild intravascular hemolysis. Data from this series did not show decreased levels haptoglobin, ruling out intravascular hemolysis in these patients with cutaneous form of loxoscelism.Dezenove pacientes que apresentaram a forma clínica cutânea do loxoscelismo foram investigados com o propósito de pesquisar hemólise intravascular sub-clínica, lançando mão da dosagem de haptoglobina, um método altamente sensível que permite detectar discreta presença de hemólise intravascular. Não foi encontrada diminuição de haptoglobina, o que descarta uma ação hemolítica do veneno da Loxosceles nestes pacientes.

  19. A Closed-Cycle Optical Cryostat and Improved Optical Elements for Studies of Dissipation at the Molecular Scale

    Science.gov (United States)

    2016-02-05

    dependent resistivity of the Au film constituting the wire . The heating is considerably enhanced when the incident polarization is aligned...Zolotavin, Douglas Natelson. Plasmonic Heating in Au nanowires at Low Temperatures, ACS Nano (02 2016) TOTAL: 1 Books Number of Manuscripts: Patents...Inventions (DD882) Scientific Progress See attachment. Technology Transfer Final report: A closed-cycle optical cryostat and

  20. Improving the efficiency of optical coherence tomography by using the non-ideal behaviour of a polarising beam splitter

    KAUST Repository

    Lippok, Norman

    2011-03-30

    We present a new way of improving the efficiency of optical coherence tomography by using the polarisation crosstalk of a polarizing beam splitter to direct most of the available source optical power to the sample. The use of a quarter wave plate in both the reference and the sample arms allows most of the sample power to be directed to the detector while adjusting the reference arm to ensure noise optimised operation. As a result, the sensitivity of such a system can be improved by 6 dB, or alternatively the acquisition time can be improved by a factor of 4 for shot noise limited performance,compared to a traditional OCT configuration using a 50/50 beam splitter. © 2011 Optical Society of America.

  1. Every photon counts: improving low, mid, and high-spatial frequency errors on astronomical optics and materials with MRF

    Science.gov (United States)

    Maloney, Chris; Lormeau, Jean Pierre; Dumas, Paul

    2016-07-01

    Many astronomical sensing applications operate in low-light conditions; for these applications every photon counts. Controlling mid-spatial frequencies and surface roughness on astronomical optics are critical for mitigating scattering effects such as flare and energy loss. By improving these two frequency regimes higher contrast images can be collected with improved efficiency. Classically, Magnetorheological Finishing (MRF) has offered an optical fabrication technique to correct low order errors as well has quilting/print-through errors left over in light-weighted optics from conventional polishing techniques. MRF is a deterministic, sub-aperture polishing process that has been used to improve figure on an ever expanding assortment of optical geometries, such as planos, spheres, on and off axis aspheres, primary mirrors and freeform optics. Precision optics are routinely manufactured by this technology with sizes ranging from 5-2,000mm in diameter. MRF can be used for form corrections; turning a sphere into an asphere or free form, but more commonly for figure corrections achieving figure errors as low as 1nm RMS while using careful metrology setups. Recent advancements in MRF technology have improved the polishing performance expected for astronomical optics in low, mid and high spatial frequency regimes. Deterministic figure correction with MRF is compatible with most materials, including some recent examples on Silicon Carbide and RSA905 Aluminum. MRF also has the ability to produce `perfectly-bad' compensating surfaces, which may be used to compensate for measured or modeled optical deformation from sources such as gravity or mounting. In addition, recent advances in MRF technology allow for corrections of mid-spatial wavelengths as small as 1mm simultaneously with form error correction. Efficient midspatial frequency corrections make use of optimized process conditions including raster polishing in combination with a small tool size. Furthermore, a novel MRF

  2. Intravascular volume administration: a contributing risk factor for intracranial hemorrhage during extracorporeal membrane oxygenation?

    NARCIS (Netherlands)

    Mol, A.C. de; Gerrits, L.C.; Heijst, A.F.J. van; Straatman, H.; Staak, F.H.J.M. van der; Liem, K.D.

    2008-01-01

    OBJECTIVE: The objective of this study was to determine the relationship between the frequency and total volume of intravascular volume administration and the development of intracranial hemorrhage during venoarterial extracorporeal membrane oxygenation. METHODS: In a retrospective, matched,

  3. Characterization of plaque components with intravascular ultrasound elastography in human femoral and coronary arteries in vitro

    NARCIS (Netherlands)

    C.L. de Korte (Chris); G. Pasterkamp (Gerard); H.A. Woutman; N. Bom (Klaas); A.F.W. van der Steen (Ton)

    2000-01-01

    textabstractBACKGROUND: The composition of plaque is a major determinant of coronary-related clinical syndromes. Intravascular ultrasound (IVUS) elastography has proven to be a technique capable of reflecting the mechanical properties of phantom material and the femoral arterial

  4. Real-time intravascular ultrasound/photoacoustic imaging system with omni-directional light excitation

    Science.gov (United States)

    Hsieh, Bao-Yu; Li, Pai-Chi

    2012-02-01

    Photoacoustic (PA) imaging has been investigated for intravascular applications. One of the main challenges is that the imaging frame rate is limited by the pulse repetition frequency (PRF), thus making real-time imaging difficult with most high-power solid-state pulse lasers. The goal of this study is to combine omni-directional optical excitation with a ring array transducer for high-frame-rate imaging, so that the image frame rate is the same as the laser PRF. In the preliminary study, we developed a real-time integrated IVUS/IVPA imaging system by modifying an IVUS system in combination with a high-speed Nd:YLF pulsed laser. In addition, an optical fiber with axicon-like distal tip is designed for omni-directional excitation. In this design, a PA image is acquired without rotating the laser light. The imaging frame rate of this integrated imaging system is 19 fps. Both US and PA images are recorded at the same time and co-registered in the fusion image. The US/PA images of tungsten wire, black tube and rabbit's atherosclerotic aorta were acquired with this integrated system to evaluate its imaging performance. The lateral/axial -6 dB resolution of US image is 2.56°/62.4μm. Resolution of PA imaging is 3.76°/91.5μm. The imaging system was also utilized to acquire IVUS/IVPA images of atherosclerotic rabbit's aorta in ex vivo study.

  5. Increasing concentrations of prothrombin complex concentrate induce disseminated intravascular coagulation in a pig model of coagulopathy with blunt liver injury.

    Science.gov (United States)

    Grottke, Oliver; Braunschweig, Till; Spronk, Henri M H; Esch, Stephanie; Rieg, Annette D; van Oerle, Rene; ten Cate, Hugo; Fitzner, Christina; Tolba, Rene; Rossaint, Rolf

    2011-08-18

    Despite increasing use of prothrombin complex concentrate (PCC) to treat hemorrhage-associated coagulopathy, few studies have investigated PCC in trauma, and there is a particular lack of safety data. This study was performed to evaluate PCC therapy in a porcine model of coagulopathy with blunt liver injury. Coagulopathy was induced in 27 anesthetized pigs by replacing approximately 70% blood volume with hydroxyethyl starch 130/0.4 and Ringer's lactate solution; erythrocytes were collected and retransfused. Ten minutes after trauma, animals randomly received PCC (35 or 50 IU/kg) or saline. Coagulation parameters including thromboelastometry, thrombin generation, and blood loss were monitored for 2 hours. Internal organs were examined macroscopically and histologically to determine the presence of emboli and assess liver injury. Total blood loss was significantly lower and survival was higher in both PCC groups versus the control group (P < .05). These outcomes appeared to be dose-independent. Thromboembolism was found in all animals treated with 50 IU/kg PCC; 44% also showed signs of disseminated intravascular coagulation. Liver injury was similar in all animals. In conclusion, 35 IU/kg PCC safely improved coagulation and attenuated blood loss. However, the higher dose of PCC (50 IU/kg) appeared to increase the risk of thromboembolism and disseminated intravascular coagulation.

  6. Exploiting Deep Matching and SAR Data for the Geo-Localization Accuracy Improvement of Optical Satellite Images

    Directory of Open Access Journals (Sweden)

    Nina Merkle

    2017-06-01

    Full Text Available Improving the geo-localization of optical satellite images is an important pre-processing step for many remote sensing tasks like monitoring by image time series or scene analysis after sudden events. These tasks require geo-referenced and precisely co-registered multi-sensor data. Images captured by the high resolution synthetic aperture radar (SAR satellite TerraSAR-X exhibit an absolute geo-location accuracy within a few decimeters. These images represent therefore a reliable source to improve the geo-location accuracy of optical images, which is in the order of tens of meters. In this paper, a deep learning-based approach for the geo-localization accuracy improvement of optical satellite images through SAR reference data is investigated. Image registration between SAR and optical images requires few, but accurate and reliable matching points. These are derived from a Siamese neural network. The network is trained using TerraSAR-X and PRISM image pairs covering greater urban areas spread over Europe, in order to learn the two-dimensional spatial shifts between optical and SAR image patches. Results confirm that accurate and reliable matching points can be generated with higher matching accuracy and precision with respect to state-of-the-art approaches.

  7. Angled-focused 45 MHz PMN-PT single element transducer for intravascular ultrasound imaging.

    Science.gov (United States)

    Yoon, Sangpil; Williams, Jay; Kang, Bong Jin; Yoon, Changhan; Cabrera-Munoz, Nestor; Jeong, Jong Seob; Lee, Sang Goo; Shung, K Kirk; Kim, Hyung Ham

    2015-06-01

    A transducer with an angled and focused aperture for intravascular ultrasound imaging has been developed. The acoustic stack for the angled-focused transducer was made of PMN-PT single crystal with one matching layer, one protective coating layer, and a highly damped backing layer. It was then press-focused to a desired focal length and inserted into a thin needle housing with an angled tip. A transducer with an angled and unfocused aperture was also made, following the same fabrication procedure, to compare the performance of the two transducers. The focused and unfocused transducers were tested to measure their center frequencies, bandwidths, and spatial resolutions. Lateral resolution of the angled-focused transducer (AFT) improved more than two times compared to that of the angled-unfocused transducer (AUT). A tissue-mimicking phantom in water and a rabbit aorta tissue sample in rabbit blood were scanned using AFT and AUT. Imaging with AFT offered improved contrast, over imaging with AUT, of the tissue-mimicking phantom and the rabbit aorta tissue sample by 23 dB and 8 dB, respectively. The results show that AFT has strong potential to provide morphological and pathological information of coronary arteries with high resolution and high contrast.

  8. Improved thermal-vacuum compatible flat plate radiometric source for system-level testing of remote optical sensors

    Science.gov (United States)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2016-09-01

    In this work, we describe an improved thermal-vacuum compatible flat plate radiometric source which has been developed and utilized for the characterization and calibration of remote optical sensors. This source is unique in that it can be used in situ, in both ambient and thermal-vacuum environments, allowing it to follow the sensor throughout its testing cycle. The performance of the original flat plate radiometric source was presented at the 2009 SPIE1. Following the original efforts, design upgrades were incorporated into the source to improve both radiometric throughput and uniformity. The pre-thermal-vacuum (pre-TVAC) testing results of a spacecraft-level optical sensor with the improved flat plate illumination source, both in ambient and vacuum environments, are presented. We also briefly discuss potential FPI configuration changes in order to improve its radiometric performance. Keywords: Calibration, radiometry, remote sensing, source.

  9. MRI phenotypes of localized intravascular coagulopathy in venous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Kevin S.H. [Boston Children' s Hospital, Department of Radiology, Boston, MA (United States); Dowd, Christopher F.; Hess, Christopher P. [University of California, San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Mathes, Erin F.; Frieden, Ilona J. [University of California, San Francisco, Department of Dermatology, San Francisco, CA (United States); Rosbe, Kristina W. [University of California, San Francisco, Department of Otolaryngology, San Francisco, CA (United States); Hoffman, William Y. [University of California, San Francisco, Department of Surgery, San Francisco, CA (United States)

    2015-10-15

    The incidence of localized intravascular coagulopathy (LIC) in venous malformations varies with lesion size and location, as well as the presence of palpable phleboliths. The development of LIC can cause pain and hemorrhage and can progress to disseminated intravascular coagulopathy (DIC) and thromboembolic disease resulting in death in some cases. Early recognition of LIC can relieve symptoms and prevent progression to life-threatening complications. The aim of this work was to identify MRI features of venous malformation associated with LIC. We hypothesized that venous malformations with larger capacitance, slower flow and less physiological compression (greater stasis) were more likely to be associated with LIC. In this HIPAA-compliant and IRB-approved study, we retrospectively reviewed clinical records and MRI for consecutive patients undergoing evaluation of venous malformations at our multidisciplinary Birthmarks and Vascular Anomalies Center between 2003 and 2013. Inclusion required consensus diagnosis of venous malformation and availability of laboratory data and MRI; patients on anticoagulation or those previously undergoing surgical or endovascular treatment were excluded. LIC was diagnosed when D-dimer exceeded 1,000 ng/mL and/or fibrinogen was less than 200 mg/dL. Two board-certified radiologists assessed the following MRI features for each lesion: morphology (spongiform vs. phlebectatic), presence of phleboliths, size, location (truncal vs. extremity), and tissue type(s) involved (subcutis, muscle, bone and viscera). Univariate logistic regression analyses were used to test associations between LIC and MRI findings, and stepwise regression was applied to assess the significance of the individual imaging predictors. Seventy patients, 37 with LIC, met inclusion criteria during the 10-year study period (age: 14.5 +/- 13.6 years [mean +/- standard deviation]; 30 male, 40 female). Both elevated D-dimer and low fibrinogen were associated with the presence of

  10. Correction of Antithrombin III Deficiency in Disseminated Intravascular Coagulation

    Directory of Open Access Journals (Sweden)

    Ye. L. Neporada

    2008-01-01

    Full Text Available Although antithrombin (AT III concentrate therapy is attended by an increased risk of hemorrhage, the data available in the literature suggest that the agent may have a positive effect on outcome in disseminated intravascular coagulation (DIC. Administration of fresh frozen plasma (FFP is associated with a less risk of hemorrhage; however, there is no evidence for its impact on prognosis in DIC. Objective: to compare the effects of AT concentrate and FFP on the activity of AT and on the clinical course of DIC. Subjects and methods. Forty-three patients diagnosed as having as DIC (according to the JAAM scale and <70% AT deficiency were included into a randomized clinical study. The inclusion criteria were as follows: age less than 16 years and more than 75 years; malignancy; hemorrhage; hemostatic therapy; a thrombocytopenia of <50X109/l. The patients were randomized into 3 groups: A AT concentrate 500— 1000 IU/day; B FFP 10 ml/kg/day; C combined therapy. The agents were daily administered for 4 days in a persistent AT deficiency of 70%. Nadroparin, 95 IU AXa/kg/day, was used as concurrent therapy. Results. The activity of AT substantially increased in Group A and great differences between Groups A and B preserved during therapy: 69±16 and 51±14% (p=0.007; 72±18 and 56±13% (p=0.02; 73±14 and 57±16% (p=0.03, respectively. No significant differences were found in the severity of respiratory disorders, dysfunction of other organs, DIC scale scores, the incidence of hemorrhages (2 cases in Group A, allergic reactions (2 cases of urticaria in Group C and in 30-day mortality — 40, 53.3, and 30.8% in Groups A, B, and C, respectively. Conclusion. As compared with FFP and combined therapy, AT concentrate therapy for DIC provides a more effective correction of AT deficiency. Further studies are needed to compare the impact of three therapy modalities on the outcome and incidence of complications in DIC. Key words: disseminated intravascular

  11. Improved Thermal-Vacuum Compatible Flat Plate Radiometric Souce for System-Level Testing of Optical Sensors

    Science.gov (United States)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2015-01-01

    This work describes the development of an improved vacuum compatible flat plate radiometric source used for characterizing and calibrating remote optical sensors, in situ, throughout their testing period. The original flat plate radiometric source was developed for use by the VIIRS instrument during the NPOESS Preparatory Project (NPP). Following this effort, the FPI has had significant upgrades in order to improve both the radiometric throughput and uniformity. Results of the VIIRS testing with the reconfigured FPI are reported and discussed.

  12. Improvement of the chromatic dispersion tolerance in coherent optical OFDM systems using shifted DFT windows for ultra-long-haul optical transmission systems.

    Science.gov (United States)

    Sung, Minkyu; Kim, Hoon; Lee, Jaehoon; Jeong, Jichai

    2014-09-22

    In a high-capacity ultra-long-haul optical coherent orthogonal frequency-division multiplexing (CO-OFDM) system, the dispersion tolerance is determined by the length of cyclic extension (CE). In this paper, we propose a novel scheme to substantially improve the dispersion tolerance of CO-OFDM systems without increasing the CE length. Multiple time-shifted discrete Fourier transform (DFT) windows are exploited at the receiver, each demodulating only a part of the subcarriers. Effectively, the proposed scheme reduces the bandwidth of the OFDM signals under demodulation. Numerical simulations are performed to show the improved dispersion tolerance of the proposed scheme in comparison with the conventional CO-OFDM system. We show that the dispersion tolerance improves by a factor equal to the number of DFT windows. The tradeoff between the improved dispersion tolerance and increased receiver complexity is also presented.

  13. Improved MODIS Dark Target aerosol optical depth algorithm over land: angular effect correction

    Science.gov (United States)

    Wu, Yerong; de Graaf, Martin; Menenti, Massimo

    2016-11-01

    Aerosol optical depth (AOD) product retrieved from MODerate Resolution Imaging Spectroradiometer (MODIS) measurements has greatly benefited scientific research in climate change and air quality due to its high quality and large coverage over the globe. However, the current product (e.g., Collection 6) over land needs to be further improved. The is because AOD retrieval still suffers large uncertainty from the surface reflectance (e.g., anisotropic reflection) although the impacts of the surface reflectance have been largely reduced using the Dark Target (DT) algorithm. It has been shown that the AOD retrieval over dark surface can be improved by considering surface bidirectional distribution reflectance function (BRDF) effects in previous study. However, the relationship of the surface reflectance between visible and shortwave infrared band that applied in the previous study can lead to an angular dependence of the AOD retrieval. This has at least two reasons. The relationship based on the assumption of isotropic reflection or Lambertian surface is not suitable for the surface bidirectional reflectance factor (BRF). However, although the relationship varies with the surface cover type by considering the vegetation index NDVISWIR, this index itself has a directional effect and affects the estimation of the surface reflection, and it can lead to some errors in the AOD retrieval. To improve this situation, we derived a new relationship for the spectral surface BRF in this study, using 3 years of data from AERONET-based Surface Reflectance Validation Network (ASRVN). To test the performance of the new algorithm, two case studies were used: 2 years of data from North America and 4 months of data from the global land. The results show that the angular effects of the AOD retrieval are largely reduced in most cases, including fewer occurrences of negative retrievals. Particularly, for the global land case, the AOD retrieval was improved by the new algorithm compared to the

  14. Stem Cell Ophthalmology Treatment Study (SCOTS) for retinal and optic nerve diseases:a case report of improvement in relapsing auto-immune optic neuropathy

    Institute of Scientific and Technical Information of China (English)

    Jeffrey N Weiss; Steven Levy; Susan C Benes

    2015-01-01

    We present the results from a patient with relapsing optic neuropathy treated within the Stem Cell Ophthalmology Treatment Study (SCOTS). SCOTS is an Institutional Review Board ap-proved clinical trial and has become the largest ophthalmology stem cell study registered at the National Institutes of Health to date (www.clinicaltrials.gov Identiifer NCT 01920867). SCOTS utilizes autologous bone marrow-derived stem cells (BMSCs) for treatment of retinal and optic nerve diseases. Pre-treatment and post-treatment comprehensive eye exams of a 54 year old female patient were performed both at the Florida Study Center, USA and at The Eye Center of Columbus, USA. As a consequence of a relapsing optic neuritis, the patient’s previously normal visual acuity decreased to between 20/350 and 20/400 in the right eye and to 20/70 in the left eye. Signiifcant visual ifeld loss developed bilaterally. The patient underwent a right eye vitrectomy with injection of BMSCs into the optic nerve of the right eyeand retrobulbar, subtenon and in-travitreal injection of BMSCs in the left eye. At 15 months after SCOTS treatment, the patient’s visual acuity had improved to 20/150 in the right eye and 20/20 in the left eye. Bilateral visual fields improved markedly. Both macular thickness and fast retinal nerve fiber layer thickness were maximally improved at 3 and 6 months after SCOTS treatment. The patient also reduced her mycophenylate dose from 1,500 mg per day to 500 mg per day and required no steroid pulse therapy during the 15-month follow up.

  15. Improving Calculation Accuracies of Accumulation-Mode Fractions Based on Spectral of Aerosol Optical Depths

    Science.gov (United States)

    Ying, Zhang; Zhengqiang, Li; Yan, Wang

    2014-03-01

    Anthropogenic aerosols are released into the atmosphere, which cause scattering and absorption of incoming solar radiation, thus exerting a direct radiative forcing on the climate system. Anthropogenic Aerosol Optical Depth (AOD) calculations are important in the research of climate changes. Accumulation-Mode Fractions (AMFs) as an anthropogenic aerosol parameter, which are the fractions of AODs between the particulates with diameters smaller than 1μm and total particulates, could be calculated by AOD spectral deconvolution algorithm, and then the anthropogenic AODs are obtained using AMFs. In this study, we present a parameterization method coupled with an AOD spectral deconvolution algorithm to calculate AMFs in Beijing over 2011. All of data are derived from AErosol RObotic NETwork (AERONET) website. The parameterization method is used to improve the accuracies of AMFs compared with constant truncation radius method. We find a good correlation using parameterization method with the square relation coefficient of 0.96, and mean deviation of AMFs is 0.028. The parameterization method could also effectively solve AMF underestimate in winter. It is suggested that the variations of Angstrom indexes in coarse mode have significant impacts on AMF inversions.

  16. Investigation of the effect of Mg doping for improvements of optical and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Caglar, Mujdat, E-mail: mcaglar@anadolu.edu.tr; Caglar, Yasemin; Ilican, Saliha

    2016-03-15

    Sol–gel spin coating method was used for the deposition of nanostructured undoped and Mg doped ZnO films. The effects of magnesium incorporation on the crystalline structure were investigated by XRD measurements and the structural deterioration was observed in the crystalline quality of the films with respect to increasing in Mg doping. All the samples exhibited a wurtzite structure. From the scanning electron microscopy (SEM) images obtained to investigate the surface morphology it was detected that an increase in Mg doping caused an improvement on the surface roughness and a reduction in the number of voids on the surface. To evaluate the absorption edges of the produced samples depending on the Mg, different methods were used and according to the obtained results, a shifting towards to high energies for the optical band gap was observed in each method. By using the single oscillator model, developed by DiDomenico and Wemple, the refractive index dispersion of the films was analyzed. E{sub o} and E{sub d} values of the 5% Mg doped film were found to be 5.76 eV and 11.80 eV, respectively. Within the scope of electrical properties, from Hall effect measurements, it was determined that all the films exhibited n-type behavior and the carrier concentration increased from 1.49×10{sup 16} to 1.20×10{sup 17} cm{sup −3} with increasing Mg doping.

  17. Improving the surface-brightness color relation for early-type stars using optical interferometry

    CERN Document Server

    Challouf, M; Mourard, D; Graczyk, D; Aroui, H; Chesneau, O; Delaa, O; Pietrzyński, G; Gieren, W; Ligi, R; Meilland, A; Perraut, K; Tallon-Bosc, I; McAlister, H; Brummelaar, T ten; Sturmann, J; Sturmann, L; Turner, N; Farrington, C; Vargas, N; Scott, N

    2014-01-01

    The aim of this work is to improve the SBC relation for early-type stars in the $-1 \\leq V-K \\leq 0$ color domain, using optical interferometry. Observations of eight B- and A-type stars were secured with the VEGA/CHARA instrument in the visible. The derived uniform disc angular diameters were converted into limb darkened angular diameters and included in a larger sample of twenty four stars, already observed by interferometry, in order to derive a revised empirical relation for O, B, A spectral type stars with a V-K color index ranging from -1 to 0. We also take the opportunity to check the consistency of the SBC relation up to $V-K \\simeq 4$ using 100 additional measurements. We determined the uniform disc angular diameter for the eight following stars: $\\gamma$ Ori, $\\zeta$ Per, $8$ Cyg, $\\iota$ Her, $\\lambda$ Aql, $\\zeta$ Peg, $\\gamma$ Lyr and $\\delta$ Cyg with V-K color ranging from -0.70 to 0.02 and typical precision of about $1.5\\%$. Using our total sample of 132 stars with $V-K$ colors index ranging f...

  18. Application of improved homogeneity similarity-based denoising in optical coherence tomography retinal images.

    Science.gov (United States)

    Chen, Qiang; de Sisternes, Luis; Leng, Theodore; Rubin, Daniel L

    2015-06-01

    Image denoising is a fundamental preprocessing step of image processing in many applications developed for optical coherence tomography (OCT) retinal imaging--a high-resolution modality for evaluating disease in the eye. To make a homogeneity similarity-based image denoising method more suitable for OCT image removal, we improve it by considering the noise and retinal characteristics of OCT images in two respects: (1) median filtering preprocessing is used to make the noise distribution of OCT images more suitable for patch-based methods; (2) a rectangle neighborhood and region restriction are adopted to accommodate the horizontal stretching of retinal structures when observed in OCT images. As a performance measurement of the proposed technique, we tested the method on real and synthetic noisy retinal OCT images and compared the results with other well-known spatial denoising methods, including bilateral filtering, five partial differential equation (PDE)-based methods, and three patch-based methods. Our results indicate that our proposed method seems suitable for retinal OCT imaging denoising, and that, in general, patch-based methods can achieve better visual denoising results than point-based methods in this type of imaging, because the image patch can better represent the structured information in the images than a single pixel. However, the time complexity of the patch-based methods is substantially higher than that of the others.

  19. Improved FEC Code Based on Concatenated Code for Optical Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    YUAN Jian-guo; JIANG Ze; MAO You-ju

    2006-01-01

    The improved three novel schemes of the super forward error correction(super-FEC) concatenated codes are proposed after the development trend of long-haul optical transmission systems and the defects of the existing FEC codes have been analyzed. The performance simulation of the Reed-Solomon(RS)+Bose-Chaudhuri-Hocguenghem(BCH) inner-outer serial concatenated code is implemented and the conceptions of encoding/decoding the parallel-concatenated code are presented. Furthermore,the simulation results for the RS(255,239)+RS(255,239) code and the RS(255,239)+RS(255,223) code show that the two consecutive concatenated codes are a superior coding scheme with such advantages as the better error correction,moderate redundancy and easy realization compared to the classic RS(255,239) code and other codes,and their signal to noise ratio gains are respectively 2~3 dB more than that of the RS(255,239)code at the bit error rate of 1×10-13. Finally,the frame structure of the novel consecutive concatenated code is arranged to lay a firm foundation in designing its hardware.

  20. Improved PeT molecules for optically sensing voltage in neurons.

    Science.gov (United States)

    Woodford, Clifford R; Frady, E Paxon; Smith, Richard S; Morey, Benjamin; Canzi, Gabriele; Palida, Sakina F; Araneda, Ricardo C; Kristan, William B; Kubiak, Clifford P; Miller, Evan W; Tsien, Roger Y

    2015-02-11

    VoltageFluor (VF) dyes have the potential to measure voltage optically in excitable membranes with a combination of high spatial and temporal resolution essential to better characterize the voltage dynamics of large groups of excitable cells. VF dyes sense voltage with high speed and sensitivity using photoinduced electron transfer (PeT) through a conjugated molecular wire. We show that tuning the driving force for PeT (ΔGPeT + w) through systematic chemical substitution modulates voltage sensitivity, estimate (ΔGPeT + w) values from experimentally measured redox potentials, and validate the voltage sensitivities in patch-clamped HEK cells for 10 new VF dyes. VF2.1(OMe).H, with a 48% ΔF/F per 100 mV, shows approximately 2-fold improvement over previous dyes in HEK cells, dissociated rat cortical neurons, and medicinal leech ganglia. Additionally, VF2.1(OMe).H faithfully reports pharmacological effects and circuit activity in mouse olfactory bulb slices, thus opening a wide range of previously inaccessible applications for voltage-sensitive dyes.

  1. Label-Enhanced Surface Plasmon Resonance: A New Concept for Improved Performance in Optical Biosensor Analysis

    Directory of Open Access Journals (Sweden)

    Niko Granqvist

    2013-11-01

    Full Text Available Surface plasmon resonance (SPR is a well-established optical biosensor technology with many proven applications in the study of molecular interactions as well as in surface and material science. SPR is usually applied in the label-free mode which may be advantageous in cases where the presence of a label may potentially interfere with the studied interactions per se. However, the fundamental challenges of label-free SPR in terms of limited sensitivity and specificity are well known. Here we present a new concept called label-enhanced SPR, which is based on utilizing strongly absorbing dye molecules in combination with the evaluation of the full shape of the SPR curve, whereby the sensitivity as well as the specificity of SPR is significantly improved. The performance of the new label-enhanced SPR method was demonstrated by two simple model assays: a small molecule assay and a DNA hybridization assay. The small molecule assay was used to demonstrate the sensitivity enhancement of the method, and how competitive assays can be used for relative affinity determination. The DNA assay was used to demonstrate the selectivity of the assay, and the capabilities in eliminating noise from bulk liquid composition variations.

  2. Multimodal nonlinear optical microscopy improves the accuracy of early diagnosis of squamous intraepithelial neoplasia

    Science.gov (United States)

    Teh, Seng Khoon; Zheng, Wei; Li, Shuxia; Li, Dong; Zeng, Yan; Yang, Yanqi; Qu, Jianan Y.

    2013-03-01

    We explore diagnostic utility of a multicolor excitation multimodal nonlinear optical (NLO) microscopy for noninvasive detection of squamous epithelial precancer in vivo. The 7,12-dimenthylbenz(a)anthracene treated hamster cheek pouch was used as an animal model of carcinogenesis. The NLO microscope system employed was equipped with the ability to collect multiple tissue endogenous NLO signals such as two-photon excited fluorescence of keratin, nicotinamide adenine dinucleotide, collagen, and tryptophan, and second harmonic generation of collagen in spectral and time domains simultaneously. A total of 34 (11 controlled and 23 treated) Golden Syrian hamsters with 62 in vivo spatially distinct measurement sites were assessed in this study. High-resolution label-free NLO images were acquired from stratum corneum, stratum granulosum-stratum basale, and stroma for all tissue measurement sites. A total of nine and eight features from 745 and 600 nm excitation wavelengths, respectively, involving tissue structural and intrinsic biochemical properties were found to contain significant diagnostic information for precancers detection (p<0.05). Particularly, 600 nm excited tryptophan fluorescence signals emanating from stratum corneum was revealed to provide remarkable diagnostic utility. Multivariate statistical techniques confirmed the integration of diagnostically significant features from multicolor excitation wavelengths yielded improved diagnostic accuracy as compared to using the individual wavelength alone.

  3. Improved optics for automatic stored-seam tracking on an electron-beam welder

    Energy Technology Data Exchange (ETDEWEB)

    Kitzke, K.A.

    1978-11-24

    A commercial 7.5-kW electron-beam welder has been optically upgraded. The viewing system has been replaced by high-resolution optics (36 line pairs per millimeter (36l/mm) with video option. A high-intensity arc lamp provides illumination of the weld region. The upgraded optical system provides the capability for making accurate and repeatable welds with computer-automated seam tracking.

  4. Application of Near Infrared Spectroscopy, Intravascular Ultrasound and the Coronary Calcium Score to Predict Adverse Coronary Events

    Science.gov (United States)

    2015-10-01

    Award Number: W81XWH-11-1-0831 TITLE: Application of Near Infrared Spectroscopy, Intravascular Ultrasound and the Coronary Calcium Score to...3. DATES COVERED 26-SEP-2014 to 25-SEP-2015 4. TITLE AND SUBTITLE Application of Near Infrared Spectroscopy, Intravascular Ultrasound and the...planned. 15. SUBJECT TERMS coronary artery disease, near infrared spectroscopy, calcium scoring, intravascular ultrasound 16. SECURIY CLASSIFICATION OF

  5. Improvement of the optical and morphological properties of microlens arrays fabricated by laser using a sol–gel coating

    Energy Technology Data Exchange (ETDEWEB)

    Nieto, Daniel, E-mail: daniel.nieto@usc.es [Microoptics and GRIN Optics Group, Applied Physics Department, Faculty of Physics, University of Santiago de Compostela, Santiago de Compostela E15782 (Spain); Gómez-Varela, Ana Isabel [Microoptics and GRIN Optics Group, Applied Physics Department, Faculty of Physics, University of Santiago de Compostela, Santiago de Compostela E15782 (Spain); Martín, Yolanda Castro [Instituto de Cerámica y Vidrio (CSIC), Kelsen 5, Campus de Cantoblanco, 28049 Madrid (Spain); O’Connor, Gerard M. [School of Physics, National Centre for Laser Applications, National University of Ireland, University Road, Galway (Ireland); Flores-Arias, María Teresa, E-mail: maite.flores@usc.es [Microoptics and GRIN Optics Group, Applied Physics Department, Faculty of Physics, University of Santiago de Compostela, Santiago de Compostela E15782 (Spain)

    2015-10-01

    Highlights: • Microlens arrays were fabricated on soda-lime glass using a Ti:Sapphire laser. • A SiO{sub 2} coating prepared via sol–gel route was used to improve the microlens quality. • The sol–gel coating was deposited at the microlens top surface using a dip coating. • Optical properties of the microlenses were improved by the coating. - Abstract: We present a simple, repeatable and non-contaminant method to improve the optical and morphological properties of microlens arrays. It consists on depositing hybrid SiO{sub 2} (TEOS, MTES) coatings via sol–gel route onto microlens arrays fabricated using a Ti:Sapphire Femtosecond Amplitude Systems S-pulse HP laser operating at 1030 nm. The deposited silica sol–gel layer reduces the surface roughness (quantified as the root mean square) and increases the quality of the interstices between the microlenses generated by the ablation process, thus improving the contrast and homogeneity of the foci of the microlens array. The proposed technique allows us to obtain microlenses with a diameter in the range of 15–20 μm and a depth of 1.5–15 μm. For the characterization of the micro-optical structures, the UV–visible spectroscopy, spectral ellipsometry, confocal microscopy and beam profilometry were used. The proof-of-principle presented in this paper can be used to improve the optical and morphological properties of micro-optical systems of different nature by tailoring the parameters involved in both the laser ablation and sol–gel processes comprising the starting materials, solvent and catalysts nature and concentration, hydrolysis ratio, aging time and/or deposition conditions.

  6. Improved silica-PLC Mach-Zehnder interferometer type optical switches with error dependence compensation of directional coupler

    Science.gov (United States)

    Wang, Jun; Yi, Jia; Guo, Lijun; Liu, Peng; Hall, Trevor J.; Sun, DeGui

    2017-03-01

    For the most popular structure of planer lightwave circuit (PLC) 2×2 thermo-optic switches, Mach-Zehnder interferometer (MZI), a full range of splitting ratio errors of directional coupler (DC) are investigated. All the parameters determining the splitting ratio are the dimensions and the refractive indices of the waveguide core and cladding layers. In this work, the coherent relationships between the waveguide size and the refractive indices are analyzed and then the error compensation between the width and the refractive index of waveguide core, and the controllable effect of over clad layer refractive index error upon the MZI-type optical switch are all discovered with numerical calculation and BPM simulations. Then, an MZI-type 2×2 thermo-optic switch having a higher error tolerance is established with the efficient optimizations of all the 3 dB-DC parameters. As a result, for the symmetric MZI switch, an insertion loss of 1.5 dB and optical extinction ratio of over 20 dB are realized for the average tolerance of±5.0%. An asymmetric arm optical phase and unequal arm lengths is also employed to improve the uniformities of insertion loss. The agreements between the designs and the experiments are recognized, leading to a wide adoption of practical silica-PLC optical switch products.

  7. Improving Mars-GRAM: Increasing the Accuracy of Sensitivity Studies at Large Optical Depths

    Science.gov (United States)

    Justh, Hilary L.; Justus, C. G.; Badger, Andrew M.

    2010-01-01

    Extensively utilized for numerous mission applications, the Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model. In a Monte-Carlo mode, Mars-GRAM's perturbation modeling capability is used to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). Mars-GRAM has been found to be inexact when used during the Mars Science Laboratory (MSL) site selection process for sensitivity studies for MapYear=0 and large optical depth values such as tau=3. Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM) from the surface to 80 km altitude. Mars-GRAM with the MapYear parameter set to 0 utilizes results from a MGCM run with a fixed value of tau=3 at all locations for the entire year. Imprecise atmospheric density and pressure at all altitudes is a consequence of this use of MGCM with tau=3. Density factor values have been determined for tau=0.3, 1 and 3 as a preliminary fix to this pressure-density problem. These factors adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with Thermal Emission Spectrometer (TES) observations for MapYears 1 and 2 at comparable dust loading. These density factors are fixed values for all latitudes and Ls and are included in Mars-GRAM Release 1.3. Work currently being done, to derive better multipliers by including variations with latitude and/or Ls by comparison of MapYear 0 output directly against TES limb data, will be highlighted in the presentation. The TES limb data utilized in this process has been validated by a comparison study between Mars atmospheric density estimates from Mars-GRAM and measurements by Mars Global Surveyor (MGS). This comparison study was undertaken for locations on Mars of varying latitudes, Ls, and LTST. The more precise density factors will be included in Mars-GRAM 2005 Release 1.4 and thus improve the results of future sensitivity studies done for large

  8. Diagnostic criteria and laboratory tests for disseminated intravascular coagulation.

    Science.gov (United States)

    Wada, Hideo; Matsumoto, Takeshi; Hatada, Tuyoshi

    2012-12-01

    Three diagnostic criteria for disseminated intravascular coagulation (DIC) have been established by the Japanese Ministry of Health, Labor and Welfare, the International Society on Thrombosis and Hemostasis (ISTH) and the Japanese Association for Acute Medicine. The diagnostic criteria involving global coagulation tests, such as the Japanese Ministry of Health, Labor and Welfare criteria and the ISTH overt diagnostic criteria, are first-generation DIC diagnostic criteria, those involving global coagulation tests and changes in these tests such as the Japanese Association for Acute Medicine criteria, are second-generation DIC diagnostic criteria, and those including non-overt DIC diagnostic criteria involving global coagulation tests, changes in these tests and hemostatic molecular markers will be the future (third-generation) DIC diagnostic criteria. There are no significant differences in the three diagnostic criteria with respect to predicting poor outcomes. Therefore, the third generation of diagnostic criteria including hemostatic molecular markers is expected to be established. Standardization and the determination of adequate cutoff values should be required for each laboratory test.

  9. Thromboelastometry in patients with severe sepsis and disseminated intravascular coagulation.

    Science.gov (United States)

    Sivula, Mirka; Pettilä, Ville; Niemi, Tomi T; Varpula, Marjut; Kuitunen, Anne H

    2009-09-01

    Severe sepsis induces coagulopathy, which may lead to disseminated intravascular coagulation (DIC). Thromboelastometry is a point-of-care whole blood coagulation monitor, which has been validated in human endotoxemia model. We assessed thromboelastometry in severe sepsis and overt DIC and investigated its applicability in differentiating sepsis-related coagulation disturbances. Thromboelastometry (EXTEM and FIBTEM tests) and traditional coagulation assays were analyzed in 28 patients with severe sepsis, 12 of who fulfilled the criteria of overt DIC on admission. Ten healthy persons served as controls. Coagulation parameters, clotting time, clot formation time (CFT), alpha angle, maximal clot firmness (MCF) and lysis index at 60 min, were registered. In patients with overt DIC, EXTEM MCF, CFT and alpha angle differed from that in both healthy controls and patients without DIC, indicating hypocoagulation (MCF 52, 63 and 68 mm; CFT 184, 88 and 73 s; and alpha angle 58, 72 and 76 degrees , respectively, P coagulation assays showed progressively worsening coagulopathy from controls to septic patients without DIC and further to those with overt DIC. We conclude that thromboelastometry may be a valuable tool in assessing whole blood coagulation capacity in patients with severe sepsis with and without overt DIC.

  10. Primary intravascular large B-cell lymphoma of pituitary

    Directory of Open Access Journals (Sweden)

    K R Anila

    2012-01-01

    Full Text Available A 68-year-old retired nurse, who was a known hypertensive on medication, presented with prolonged fever of 2-month duration without any clinical evidence of infection. On examination she had altered mental status. She also had other nonspecific complaints such as sleep disturbances, loss of weight, etc. On investigation, she was found to have anemia, thrombocytopenia, raised erythrocyte sedimentation rate (ESR, C-reactive protein (CRP, and lactate dehydrogenase (LDH values. She also had electrolyte imbalance. Radiological evaluation of brain showed mass lesion in the sella turcica, suggestive of pituitary adenoma. Biochemical evaluation showed hypopituitarism. Trans-sphenoidal biopsy was done. Based on histopathological and immunohistochemical findings a diagnosis of intravascular large B-cell lymphoma (IVLBCL of pituitary was made. Our patient′s condition deteriorated rapidly and she succumbed to her illness before therapy could be initiated. We are reporting this case because of the rare subtype of large B-cell lymphoma presenting at an extremely unusual primary site.

  11. Huge Intravascular Tumor Extending to the Heart: Leiomyomatosis

    Directory of Open Access Journals (Sweden)

    Suat Doganci

    2015-01-01

    Full Text Available Intravenous leiomyomatosis (IVL is a rare neoplasm characterized by histologically benign-looking smooth muscle cell tumor mass, which is growing within the intrauterine and extrauterine venous system. In this report we aimed to present an unusual case of IVL, which is originating from iliac vein and extended throughout to right cardiac chambers. A 49-year-old female patient, who was treated with warfarin sodium due to right iliac vein thrombosis, was admitted to our department with intermittent dyspnea, palpitation, and dizziness. Physical examination was almost normal except bilateral pretibial edema. On magnetic resonance venography, there was an intravenous mass, which is originated from right internal iliac vein and extended into the inferior vena cava. Transthoracic echocardiography and transesophageal echocardiography revealed a huge mass extending from the inferior vena cava through the right atrium, with obvious venous occlusion. Thoracic, abdominal, and pelvic MR showed an intravascular mass, which is concordant with leiomyomatosis. Surgery was performed through median sternotomy. A huge mass with 25-cm length and 186-gr weight was excised through right atrial oblique incision, on beating heart with cardiopulmonary bypass. Histopathologic assessment was compatible with IVL. Exact strategy for the surgical treatment of IVL is still controversial. We used one-stage approach, with complete resection of a huge IVL extending from right atrium to right iliac vein. In such cases, high recurrence rate is a significant problem; therefore it should be kept in mind.

  12. Huge Intravascular Tumor Extending to the Heart: Leiomyomatosis.

    Science.gov (United States)

    Doganci, Suat; Kaya, Erkan; Kadan, Murat; Karabacak, Kubilay; Erol, Gökhan; Demirkilic, Ufuk

    2015-01-01

    Intravenous leiomyomatosis (IVL) is a rare neoplasm characterized by histologically benign-looking smooth muscle cell tumor mass, which is growing within the intrauterine and extrauterine venous system. In this report we aimed to present an unusual case of IVL, which is originating from iliac vein and extended throughout to right cardiac chambers. A 49-year-old female patient, who was treated with warfarin sodium due to right iliac vein thrombosis, was admitted to our department with intermittent dyspnea, palpitation, and dizziness. Physical examination was almost normal except bilateral pretibial edema. On magnetic resonance venography, there was an intravenous mass, which is originated from right internal iliac vein and extended into the inferior vena cava. Transthoracic echocardiography and transesophageal echocardiography revealed a huge mass extending from the inferior vena cava through the right atrium, with obvious venous occlusion. Thoracic, abdominal, and pelvic MR showed an intravascular mass, which is concordant with leiomyomatosis. Surgery was performed through median sternotomy. A huge mass with 25-cm length and 186-gr weight was excised through right atrial oblique incision, on beating heart with cardiopulmonary bypass. Histopathologic assessment was compatible with IVL. Exact strategy for the surgical treatment of IVL is still controversial. We used one-stage approach, with complete resection of a huge IVL extending from right atrium to right iliac vein. In such cases, high recurrence rate is a significant problem; therefore it should be kept in mind.

  13. Biochemistry and pathophysiology of intravascular and intracellular lipolysis.

    Science.gov (United States)

    Young, Stephen G; Zechner, Rudolf

    2013-03-01

    All organisms use fatty acids (FAs) for energy substrates and as precursors for membrane and signaling lipids. The most efficient way to transport and store FAs is in the form of triglycerides (TGs); however, TGs are not capable of traversing biological membranes and therefore need to be cleaved by TG hydrolases ("lipases") before moving in or out of cells. This biochemical process is generally called "lipolysis." Intravascular lipolysis degrades lipoprotein-associated TGs to FAs for their subsequent uptake by parenchymal cells, whereas intracellular lipolysis generates FAs and glycerol for their release (in the case of white adipose tissue) or use by cells (in the case of other tissues). Although the importance of lipolysis has been recognized for decades, many of the key proteins involved in lipolysis have been uncovered only recently. Important new developments include the discovery of glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1), the molecule that moves lipoprotein lipase from the interstitial spaces to the capillary lumen, and the discovery of adipose triglyceride lipase (ATGL) and comparative gene identification-58 (CGI-58) as crucial molecules in the hydrolysis of TGs within cells. This review summarizes current views of lipolysis and highlights the relevance of this process to human disease.

  14. Simultaneous morphological and biochemical endogenous optical imaging of atherosclerosis.

    Science.gov (United States)

    Jo, Javier A; Park, Jesung; Pande, Paritosh; Shrestha, Sebina; Serafino, Michael J; Rico Jimenez, J de Jesus; Clubb, Fred; Walton, Brian; Buja, L Maximilian; Phipps, Jennifer E; Feldman, Marc D; Adame, Jessie; Applegate, Brian E

    2015-08-01

    The aim of this study was to validate novel imaging technology for simultaneous morphological and biochemical endogenous optical imaging of coronary atherosclerotic plaque. Optical coherence tomography (OCT) generates high-resolution 3D images of plaque morphology and endogenous fluorescence lifetime imaging microscopy (FLIM) characterizes biochemical composition. Both imaging modalities rely on plaque's intrinsic optical characteristics, making contrast agents unnecessary. A multimodal OCT/FLIM system was utilized to generate luminal biochemical maps superimposed on high-resolution (7 µm axial and 13 µm lateral) structural volumetric images. Forty-seven fresh postmortem human coronary segments were imaged: pathological intimal thickening (PIT, n = 26), fibroatheroma (FA, n = 12), thin-cap FA (TCFA, n = 2), and fibrocalcific plaque (CA, n = 7), determined by histopathology. Multimodal images were evaluated, and each plaque identified as PIT, FA, TCFA, or CA based on expert OCT readers, and as having high-lipid (HL), high-collagen (HC), or low-collagen/low-lipid (LCL) luminal composition based on linear discriminant analysis of FLIM. Of 47 plaques, 89.4% (42/47) of the plaques were correctly identified based on OCT/FLIM evaluation using tissue histopathology and immunohistochemistry as the gold standard. Four of the misclassifications corresponded to confusing PIT with HL luminal composition for FA with HL cap. The other corresponded to confusing FA with a HC cap for FA with an LCL cap. We have demonstrated the feasibility of accurate simultaneous OCT/FLIM morphological and biochemical characterization of coronary plaques at spatial resolutions and acquisition speeds compatible with catheter-based intravascular imaging. The success of this pilot study sets up future development of a multimodal intravascular imaging system that will enable studies that could help improve our understanding of plaque pathogenesis. Published on behalf of the European Society of

  15. Intravascular ultrasound assessed incomplete stent apposition and stent fracture in stent thrombosis after bare metal versus drug-eluting stent treatment the Nordic Intravascular Ultrasound Study (NIVUS)

    DEFF Research Database (Denmark)

    Kosonen, Petteri; Vikman, Saila; Jensen, Lisette Okkels;

    2013-01-01

    This prospective multicenter registry used intravascular ultrasound (IVUS) in patients with definite stent thrombosis (ST) to compare rates of incomplete stent apposition (ISA), stent fracture and stent expansion in patients treated with drug-eluting (DES) versus bare metal (BMS) stents. ST...... is a rare, but potential life threatening event after coronary stent implantation. The etiology seems to be multifactorial....

  16. Detection and characterization of atherosclerotic plaques by Raman probe spectroscopy and optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Matthäus, Christian; Dochow, Sebastian; Egodage, Kokila D.; Schie, Iwan; Romeike, Bernd F.; Brehm, Bernhard R.; Popp, Jürgen

    2017-02-01

    Visualization and characterization of inner arterial plaque depositions is of vital diagnostic interest. Established intravascular imaging techniques provide valuable morphological information, but cannot deliver information about the chemical composition of individual plaques. Probe based Raman spectroscopy offers the possibility for a biochemical characterization of atherosclerotic plaque formations during an intravascular intervention. From post mortem studies it is well known that the severity of a plaque and its stability are strongly correlated with its biochemical composition. Especially the identification of vulnerable plaques remains one of the most important and challenging aspects in cardiology. Thus, specific information about the composition of a plaque would greatly improve the risk assessment and management. Furthermore, knowledge about the composition can offer new therapeutic and medication strategies. Plaque calcifications as well as major lipid components such as cholesterol, cholesterol esters and triglycerides can be spectroscopically easily differentiated. Intravascular optical coherence tomography (OCT) is currently a prominent catheter based imaging technique for the localization and visualization of atherosclerotic plaque depositions. The high resolution of OCT with 10 to 15 µm allows for very detailed characterization of morphological features such as different plaque formations, thin fibrous caps and accurate measurements of lesion lengths. In combination with OCT imaging the obtained spectral information can provide substantial information supporting on on-site diagnosis of various plaque types and therefor an improved risk assessment. The potential and feasibility of combining OCT with Raman spectroscopy is demonstrated on excised plaque samples, as well as under in vivo conditions. Acknowledgements: Financial support from the Carl Zeiss Foundation is greatly acknowledged.

  17. Improving surface acousto-optical interaction by high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2009-01-01

    The acousto-optical interaction of an optical wave confined inside a waveguide and a surface acoustic wave launched by an interdigital transducer (IDT) at the surface of a piezoelectric material is considered. The IDT with high aspect ratio electrodes supports several acoustic modes that are stro...

  18. Optical properties of atmospheric particles: complete parameter sets obtained through polar photometry and an improved inversion technique.

    Science.gov (United States)

    Hänel, G

    1994-10-20

    Complete sets of optical parameters of dry particles sampled on a Nuclepore filter are derived through interpretation of photometric data with an improved inversion technique. The parameters are the volume-extinction and absorption coefficients, the single-scattering albedo, the asymmetry parameter of the volume scattering function, the apparent complex refractive index, and the apparent soot content. They may serve as input data for solar radiation-budget considerations. Results from preliminary measurements taken in Central Europe and Italy show an extreme variability of the optical parameters. Both large regional and temporal variabilities have been observed caused by the fluctuating midlatitude weather systems and human activities.

  19. Improving Recording Density of All-Optical Magnetic Storage by Using High-Pass Angular Spectrum Filters

    Institute of Scientific and Technical Information of China (English)

    ZHUANG You-Yi; ZHANG Yao-Ju

    2009-01-01

    A new design is presented to improve the magnetic recording density in all-optical magnetic storage.By using the high numerical lens with a high-pass angular spectrum filter, circularly polarized laser pulses are focused into the magneto-optic film with the perpendicular anisotropy.Magnetization of the film is induced by the inverse Faraday effect.As the obstructed angle of the filter increases the magnetic recording density increases evidently.The magnetization intensity and the sidelobe effect are also discussed.

  20. Cost savings and clinical acceptability of an intravascular line tip culture triage policy.

    Science.gov (United States)

    Colston, J; Batchelor, B; Bowler, I C J W

    2013-05-01

    Culture of intravascular line tips is useful for the diagnosis of intravascular line-related phlebitis and bacteraemia. However, the test lacks specificity, with a low predictive value for intravascular line bacteraemia. A recent randomised study showed that predictive value could be increased and costs reduced by refrigerating intravascular lines and retrieving them for culture only if there was a bacteraemia in the seven days before or after the intravascular line was received. We studied whether a similar triage policy could be introduced into our 1400-bed National Health Service (NHS) teaching hospital in the UK. We assessed cost reduction in the laboratory and clinical acceptability. Data regarding the number of intravascular lines received, stored and cultured and blood cultures received was retrieved from the microbiology computer, for five-month periods before and after the introduction of the new triage policy. Of the 134 intravascular line tips received in the five months after the policy had been introduced, 101 (75%) were stored without retrieval and 33 were cultured. Of these, 7/134 (5%) were culture positive and three matched a concurrent blood culture. Audit showed that compliance with the policy was >98%. The estimated annual cost reduction following the introduction of the policy was £3,166.96. The policy was acceptable to clinicians. The policy was both cost saving and clinically acceptable. If the policy were adopted throughout the NHS in the UK, the annual cost saving to the service might be in the order of £300,000. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  1. Improved Optical Magnetometer Based on Electromagnetically Induced Transparency in a Ring-Cavity Setup

    Science.gov (United States)

    Bardhan, Bhaskar Roy; Kim, Moochan; Dowling, Jonathan

    2012-06-01

    We propose and simulate a ring-gyro optical magnetometer based on polarization rotation of an optical field in an electromagnetically induced transparency (EIT) system. By properly choosing the polarization orientations of the optical field and the transition energy levels, the transparency conditions for the polarization components are derived for the EIT system inserted into the ring-cavity setup as a cell. As the optical field passes through the cell, the fluctuations of the Rabi frequency as well as the density inside the cell, due to the fluctuations in the laser field, give rise to the dephasing of the polarization vector. We show that using the setup it is possible to achieve very sensitive measurement of the magnetic field. Besides, by making several round trips of the photons, the dephasing effects can be removed by some suitable dynamical decoupling schemes implemented with additional waveplates in the setup. This enables us to obtain long interrogation length for the EIT based optical magnetometer.

  2. Analysis and Improvement of Reflection-type Transverse Modulation Optical Voltage Sensors

    Institute of Scientific and Technical Information of China (English)

    LUO Sunan; YE Miaoyuan; XU Yan; CUI Ying

    2001-01-01

    Reflection-type transverse modulation optical voltage sensors, which employ reflection retarders to replace quarter-wave plates, are convenient for practical use. In previous literatures, the measured voltage was all applied to Bi4Ge3O12 crystal along the (110) direction for transverse modulation optical voltage sensor, and crystals are used as sensing materials. In this paper, reflection-type transverse modulation optical voltage sensor has been analyzed theoretically and a novel configuration in which the measured voltage is applied to a Bi4C-e3O12 crystal along the (001) direction with light wave passing through the crystal in the (110) direction has been proposed. According to this theoretical analysis, a novel optical voltage sensor, which can be used in a 220 kV optical fiber voltage transformer, has been designed and assembled. Experimental results showed that the linearity and the stability of the sensor during 24 hours can reach 0.3%.

  3. Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester

    Science.gov (United States)

    Azarnoush, Hamed; Vergnole, Sébastien; Bourezak, Rafik; Boulet, Benoit; Lamouche, Guy

    2010-08-01

    We present an innovative integration of an intravascular optical coherence tomography probe into a computerized balloon deployment system to monitor the balloon inflation process. The high-resolution intraluminal imaging of the balloon provides a detailed assessment of the balloon quality and, consequently, a technique to improve the balloon manufacturing process. A custom-built swept-source optical coherence tomography system is used for real-time imaging. A semicompliant balloon with a nominal diameter of 4 mm is fabricated for the experiments. Imaging results correspond to balloon deployment in air and inside an artery phantom. A characterization of the balloon diameter, wall thickness, compliance, and elastic modulus is provided, based on image segmentation. Using the images obtained from the probe pullback, a three-dimensional visualization of the inflated balloon is presented.

  4. Long-term safety and feasibility of three-vessel multimodality intravascular imaging in patients with ST-elevation myocardial infarction

    DEFF Research Database (Denmark)

    Taniwaki, Masanori; Radu, Maria D; Garcia-Garcia, Hector M

    2015-01-01

    We assessed the feasibility and the procedural and long-term safety of intracoronary (i.c) imaging for documentary purposes with optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in patients with acute ST-elevation myocardial infarction (STEMI) undergoing primary PCI in the s......We assessed the feasibility and the procedural and long-term safety of intracoronary (i.c) imaging for documentary purposes with optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in patients with acute ST-elevation myocardial infarction (STEMI) undergoing primary PCI...... in the setting of IBIS-4 study. IBIS4 (NCT00962416) is a prospective cohort study conducted at five European centers including 103 STEMI patients who underwent serial three-vessel coronary imaging during primary PCI and at 13 months. The feasibility parameter was successful imaging, defined as the number...... with the results from a cohort of 485 STEMI patients undergoing primary PCI without additional imaging. Imaging of the infarct-related artery at baseline (and follow-up) was successful in 92.2% (96.6%) of patients using OCT and in 93.2% (95.5%) using IVUS. Imaging of the non-infarct-related vessels was successful...

  5. CT-pro-AVP as a tool for assessment of intravascular volume depletion in severe hyponatremia.

    Science.gov (United States)

    Boursier, Guilaine; Alméras, Marion; Buthiau, Delphine; Jugant, Sébastien; Daubin, Delphine; Kuster, Nils; Dupuy, Anne-Marie; Ribstein, Jean; Klouche, Kada; Cristol, Jean-Paul

    2015-07-01

    Assessment of volume status is essential to best manage hyponatremic patients but is not always accurate in clinical practice. The aim of this study was to evaluate the reliability of C-terminal portion of pro-arginine-vasopressin (CT-pro-AVP), a surrogate biomarker of vasopressin release, in assessing intravascular volume (IVV) depletion in hypoosmolar hyponatremic patients. Plasma CT-pro-AVP and urea-to-creatinine ratio (Ur/Cr) were performed in 131 hospitalized patients presenting chronic severe hypoosmolar hyponatremia. At hospital discharge, their IVV was evaluated regardless of CT-pro-AVP concentrations. All patients were then classified as decreased or as normal/expanded IVV group. Plasma CT-pro-AVP levels were higher in patients with decreased IVV (34.6 vs. 11.3 pmol/L, ppro-AVP and Ur/Cr resulted in an improved ROC AUC up to 0.787 (95% CI 0.709-0.866). Our findings support the hypothesis that CT-pro-AVP plasma level may reflect IVV and would be a tool for its assessment. This performance has been magnified by its combination with Ur/Cr. A dual-marker strategy may help clinicians to optimize the management of severe hyponatremia especially in case of confusing clinical presentations. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  6. The clinical efficacy of extracorporeal and intravascular hemocorrection methods in psoriasis

    Directory of Open Access Journals (Sweden)

    Baityakov V.V.

    2012-03-01

    Full Text Available Purpose. The study of the influence of extracorporeal and intravascular hemocorrection methods (plasmapheresis, ultraviolet blood radiation, ozonetherapy and its combination on skin process and life quality in patients with extensive psoriasis. Methods. 253 patients with extensive psoriasis from the age of 18 to 72 have been investigated. PASI (Psoriasis Area and Severity Index and dermatological index of life quality (DILQ have been used for treatment assessment. Results. The inclusion of efferent quantum and ozone therapy methods in the complex treatment of psoriasis has promoted to the more rapid and complete positive dynamics of skin process and the improvement of life quality. The use of plasmapheresis and its variations with photomodification or the ozone treatment of returning erythrocyte suspension has been the most effective. Plasmapheresis and its modifications are appropriateto be used in the complex treatment of the patients with severe forms of psoriasis. Conclusion: Further study of efferent quantum and ozone therapy methods and their wider use in psoriasis therapy and other chronic dermatosis seem to be promising.

  7. Micromachined PIN-PMN-PT crystal composite transducer for high-frequency intravascular ultrasound (IVUS) imaging.

    Science.gov (United States)

    Li, Xiang; Ma, Teng; Tian, Jian; Han, Pengdi; Zhou, Qifa; Shung, K Kirk

    2014-07-01

    In this paper, we report the use of micromachined PbIn1/2Nb1/2O3-PbMg1/3Nb2/3O3-PbTiO 3 (PIN-PMNPT) single crystal 1-3 composite material for intravascular ultrasound (IVUS) imaging application. The effective electromechanical coupling coefficient kt(eff) of the composite was measured to be 0.75 to 0.78. Acoustic impedance was estimated to be 20 MRayl. Based on the composite, needle-type and flexible-type IVUS transducers were fabricated. The composite transducer achieved an 86% bandwidth at the center frequency of 41 MHz, which resulted in a 43 μm axial resolution. Ex vivo IVUS imaging was conducted to demonstrate the improvement of axial resolution. The composite transducer was capable of identifying the three layers of a cadaver coronary artery specimen with high resolution. The PIN-PMN-PT-based composite has superior piezoelectric properties comparable to PMN-PT-based composite and its thermal stability is higher than PMN-PT. PIN-PMN-PT crystal can be an alternative approach for fabricating high-frequency composite, instead of using PMN-PT.

  8. Treatment Effects of Xuebijing Injection in Severe Septic Patients with Disseminated Intravascular Coagulation

    Directory of Open Access Journals (Sweden)

    Qin Yin

    2014-01-01

    Full Text Available The treatment effects of Xuebijing (XBJ injection in severe septic patients with disseminated intravascular coagulation (DIC were investigated in this study. 171 severe septic patients with DIC were divided into the control group (n=83 or intervention group (n=88. Routine therapies were administered in both groups, and XBJ injection was administered additionally in the intervention group. Incidence of DIC, clinical severity scores, and coagulation parameters at 7 days after administration of XBJ injection were compared between the two groups, and short-term prognosis was evaluated by 28-day mortality. Compared with the control group, incidence of DIC in the intervention group was significantly lower at 7 days after administration of XBJ injection (P<0.001. In addition, differences of platelet count and prothrombin time were significantly greater in the intervention group than in the control group (P all <0.05, and similar results were also found for differences of the Mortality in Emergency Department Sepsis score and Acute Physiology and Chronic Health Evaluation II score (P all <0.05. Furthermore, 28-day mortality was significantly lower in the intervention group (P=0.034. These results demonstrate that XBJ injection can effectively treat DIC caused by severe sepsis and improve short-term prognosis of severe septic patients with DIC.

  9. Micromachined PIN-PMN-PT Crystal Composite Transducer for High-Frequency Intravascular Ultrasound (IVUS) Imaging

    Science.gov (United States)

    Li, Xiang; Ma, Teng; Tian, Jian; Han, Pengdi; Zhou, Qifa; Shung, K. Kirk

    2015-01-01

    In this paper, we report the use of micromachined PbIn1/2Nb1/2O3–PbMg1/3Nb2/3O3–PbTiO3 (PIN-PMN-PT) single crystal 1–3 composite material for intravascular ultrasound (IVUS) imaging application. The effective electromechanical coupling coefficient kt(eff) of the composite was measured to be 0.75 to 0.78. Acoustic impedance was estimated to be 20 MRayl. Based on the composite, needle-type and flexible-type IVUS transducers were fabricated. The composite transducer achieved an 86% bandwidth at the center frequency of 41 MHz, which resulted in a 43 μm axial resolution. Ex vivo IVUS imaging was conducted to demonstrate the improvement of axial resolution. The composite transducer was capable of identifying the three layers of a cadaver coronary artery specimen with high resolution. The PIN-PMN-PT-based composite has superior piezoelectric properties comparable to PMN-PT-based composite and its thermal stability is higher than PMN-PT. PIN-PMN-PT crystal can be an alternative approach for fabricating high-frequency composite, instead of using PMN-PT. PMID:24960706

  10. The Imaging Modulography Technique Revisited for High-Definition Intravascular Ultrasound: Theoretical Framework.

    Science.gov (United States)

    Tacheau, Antoine; Le Floc'h, Simon; Finet, Gérard; Doyley, Marvin M; Pettigrew, Roderic I; Cloutier, Guy; Ohayon, Jacques

    2016-03-01

    Mechanical characterization of atherosclerotic lesions remains an essential step for the detection of vulnerable plaques (VPs). Recently, an intravascular ultrasound (IVUS) elasticity reconstruction method (iMOD) has been tested in vivo by our group. The major limitation of iMOD is the need to estimate the strain field in the entire VP despite attenuated depth penetration signals when using high-definition (HD) IVUS systems. Therefore, an extended iMOD approach (E-iMOD) was designed and applied to coronary lesions of patients imaged in vivo with IVUS. The E-iMOD method (i) quantified necrotic core areas with a mean absolute relative error of 3.5 ± 3.5% and (ii) identified Young's moduli of the necrotic cores and fibrous regions with mean values of 5.7 ± 0.8 kPa and 794.5 ± 22.0 kPa instead of 5 kPa and 800 kPa, respectively. This study demonstrates the potential of the improved HD-IVUS modulography technique E-iMOD to characterize coronary VPs.

  11. Improvement of Three-Dimensional Resolution in Optical Data Storage by Combination of Two Annular Binary Phase Filters

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiao-Feng; LI Cheng-Fang; RUAN Hao

    2004-01-01

    @@ We present an improved confocal readout system to achieve three-dimensional superresolution. This improved system is based on a combination of two different annular binary phase filters, the one designed for increasing the transverse superresolution and the other for achieving axial superresolution. By adjusting the pupil parameters,each pupil can be well designed. The simulation results show that with this improved system, the area of the central lobe of the three-dimensional point spread function of the read optics is greatly reduced. Moreover, the side-lobes are extinguished.

  12. Cascaded Orientation-Patterned Gallium Arsenide Optical Parametric Oscillator for Improved Longwave Infrared Conversion Efficiency

    Science.gov (United States)

    Feaver, Ryan K.

    Optical parametric oscillators (OPOs) utilizing quasi-phase matched materials offer an appealing alternative to direct laser sources. Quasi-phase matched materials provide a useful alternative to traditional birefringent nonlinear optical materials and through material engineering, higher nonlinear coefficients can now be accessed. Orientation patterned gallium arsenide (OPGaAs) is an ideal material because of its broad IR transmission and large nonlinear coefficient. In contrast to ferroelectric materials, such as lithium niobate, where the pattern is fabricated through electric poling, zincblende materials, like OPGaAs, are grown epitaxially with the designed pattern. Generating longwave output from a much shorter pump wavelength, however, is relatively inefficiency due to the large quantum defect when compared to similar devices operating in the 3 - 5 mum regime. One method to increase pump to idler conversion efficiency is to recycle the undesired and higher energy signal photons into additional idler photons via a second nonlinear stage. An external amplifier stage can be utilized, where the signal and idler from the OPO are sent to a second nonlinear crystal in which the idler is amplified at the expense of the signal. Alternatively, the second crystal can be placed within the original OPO cavity where the signal from the first-stage acts as the pump for the second crystal and the resonant intensity of the signal is higher. Pumping the second crystal within the OPO should lead to higher conversion efficiency into the longwave idler. The grating period needed for the second crystal to use the signal from the first crystal to produce additional idler has the fortuitous advantage that it will not phase match to the original pump wavelength, avoiding unwanted nonlinear interactions. Therefore, a simple linear cavity can be utilized where the pump from the first-stage will simply propagate through the second crystal without undesired results. Without this feature

  13. Contact-geometry engineering in a circular light-emitting diode (LED) for improved electrical and optical performances

    Science.gov (United States)

    Park, Yun Soo; Lee, Hwan Gi; Yang, Chung-Mo; Kim, Dong-Seok; Bae, Jin-Hyuk; Cho, Seongjae; Lee, Jung-Hee; Kang, In Man

    2013-01-01

    GaN light-emitting diodes (LEDs) based on circular mesa structure are fabricated and their electrical and optical characterizations are performed. The uniform current flow in the circular LED (C-LED) was conducted in the radial direction, from the n-type GaN island electrode at the center to the p-type GaN ring electrode around the perimeter. The symmetric electrode structuring substantially improved the electrical and optical performances. The operating voltage for C-LED at a reference current (100 mA) was 20.9% lower than that of a conventionally structured LED (CV-LED). Also, C-LED showed 19.4% higher optical output power than CV-LED.

  14. Improvement of an optical fiber sensor for the detection of low concentrations of solutes using the photothermal effect

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado, S. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada (CICATA-Legaria), Calzada Legaria 694 Col. Irrigación, Del. Miguel Hidalgo, Mexico D.F. 11500 (Mexico); Marín, E., E-mail: emarinm@ipn.mx [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada (CICATA-Legaria), Calzada Legaria 694 Col. Irrigación, Del. Miguel Hidalgo, Mexico D.F. 11500 (Mexico); Calderón, A. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada (CICATA-Legaria), Calzada Legaria 694 Col. Irrigación, Del. Miguel Hidalgo, Mexico D.F. 11500 (Mexico); Marcano, A. [Department of Physics and Engineering and Optical Science Center for Applied Research, Delaware State University, 1200 North Dupont Highway, Dover, DE 19901 (United States)

    2014-10-10

    Highlights: • Fiber optic sensors can be used as refractometers. • Refractive index changes are generated by a laser beam through a photothermal thermal lens effect. • Concentration measurements at micromolar level are possible. • The thermal lens effect can be monitored. - Abstract: We report on the use of an optical fiber sensor for the determination of concentration of contaminants in solutions below the micromolar level based on the photothermal lens effect. A pump laser beam has been added to a conventional configuration widely used as refractometer, so that the device is improved to detect tiny changes of the refractive index of a sample related to the amount of heat generated following optical absorption. In this way, concentrations as low as 0.1 μM of methylene blue in distilled water were measured. A simple experiment is also performed to demonstrate the photothermal effect.

  15. Improve the performance of orthogonal ASK/DPSK optical label switching by DC-balanced line encoding

    DEFF Research Database (Denmark)

    Chi, Nan; Xu, Lin; Zhang, J.;

    2006-01-01

    Orthogonal amplitude shift keying/differential phase-shift keying (ASK/DPSK) labeling is a promising approach to ultrahigh packet-rate routing and forwarding in the optical layer. However, the limitation on the payload extinction ratio (ER) is a detrimental effect for network scalability and tran......Orthogonal amplitude shift keying/differential phase-shift keying (ASK/DPSK) labeling is a promising approach to ultrahigh packet-rate routing and forwarding in the optical layer. However, the limitation on the payload extinction ratio (ER) is a detrimental effect for network scalability...... and transparency. This paper presents theoretical and experimental studies of ASK/DPSK labeling. It proposes that dc-balanced 8B10B coding can greatly improve ER tolerance, which in turn leads to better system performance. By using the 8B10B coding method, the paper demonstrates transmission and optical label...

  16. New improvement of the combined optical fiber transducer for landslide monitoring

    Science.gov (United States)

    Zhu, Z.-W.; Yuan, Q.-Y.; Liu, D.-Y.; Liu, B.; Liu, J.-C.; Luo, H.

    2014-08-01

    Landslide monitoring is important in predicting the behavior of landslides, thereby ensuring environmental, life, and property safety. On the basis of our previous studies, we conducted the double shear test by using a third-generation optical fiber transducer that uses expandable polystyrene (EPS) as base material. However, the third-generation transducer has poor performance when cohesive force is present between the grout and capillary stainless steel pipe of the transducer. Thus, the fourth-generation optical fiber transducer was invented. Similar to the third-generation transducer, the fourth-generation transducer also used EPS as its base material. Single shear test was conducted on the fourth-generation transducer after being grouted with cement mortar (1 : 1 mix ratio). The micro-bend loss mechanism of the optical fiber was considered, and the optical time domain reflectometry instrument was used. The fact that the loss sequence of optical fibers subjected to loading is different at various locations is found. The relationship of the loading-point displacement vs. optical fiber sliding distance and optical loss were measured. Results show that the maximum initial measurement precision of the newly proposed device is 1 mm, the corresponding sliding distance is 21 mm, and the dynamic range is 0-20 mm. The fourth-generation transducer can measure the movement direction of loadings, thus making this transducer applicable for landslide monitoring.

  17. Improved properties of phosphor-filled luminescent down-shifting layers: reduced scattering, optical model, and optimization for PV application

    Science.gov (United States)

    Solodovnyk, Anastasiia; Lipovšek, Benjamin; Forberich, Karen; Stern, Edda; Krč, Janez; Batentschuk, Miroslaw; Topič, Marko; Brabec, Christoph J.

    2015-12-01

    We studied the optical properties of polymer layers filled with phosphor particles in two aspects. First, we used two different polymer binders with refractive indices n = 1.46 and n = 1.61 (λ = 600 nm) to decrease Δn with the phosphor particles (n = 1.81). Second, we prepared two particle size distributions D50 = 12 μm and D50 = 19 μm. The particles were dispersed in both polymer binders in several volume concentrations and coated onto glass with thicknesses of 150 - 600 μm. We present further a newly developed optical model for simulation and optimization of such luminescent down-shifting (LDS) layers. The model is developed within the ray tracing framework of the existing optical simulator CROWM (Combined Ray Optics / Wave Optics Model), which enables simulation of standalone LDS layers as well as complete solar cells (including thick and thin layers) enhanced by the LDS layers for an improved solar spectrum harvesting. Experimental results and numerical simulations show that the layers of the higher refractive index binder with larger particles result in the highest optical transmittance in the visible light spectrum. Finally we proved that scattering of the phosphor particles in the LDS layers may increase the overall light harvesting in the solar cell. We used numerical simulations to determine optimal layer composition for application in realistic thin-film photovoltaic devices. Surprisingly LDS layers with lower measured optical transmittance are more efficient when applied onto the solar cells due to graded refractive index and efficient light scattering. Therefore, our phosphor-filled LDS layers could possibly complement other light-coupling techniques in photovoltaics.

  18. Assessment of culprit lesions by intravascular ultrasound in patients with acute myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    LIU Jian; LIU Chuan-fen; LU Ming-yu; MA Yu-liang; WANG Long; CHEN Hong; WANG Wei-min

    2009-01-01

    Background Intravascular ultrasound has become the standard invasive method for diagnosing coronary artery disease. The aim of the present study was to evaluate the ability of intravascular ultrasound for assessment of culprit lesion morphology during primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI).Methods We performed 18 intravascular ultrasound assessments preintervention during the primary PCI for AMI. intravascular ultrasound analysis included qualitative and quantitative measurements of reference and lesion extemal elastic membrane (EEM), lumen, and plaque plus media (P&M) area. Positive remodeling was defined as lesion/mean reference EEM >1.0. Culprit lesions were identified by a combination of electrocardiogram (ECG) and coronary angiography.Results There was an average of 1.44 infarct-related artery (IRA) plaques per patient. The incidences of thrombus and plaque ruptures were 28% (5) and 33% (6), respectively. Hypoechoic plaque was observed in 72% (13) of AMI patients. Calcified lesions could be found in 33% (6) of culprit lesions. Sixty percent of the culprit lesion sites presented with positive remodeling.Conclusions Intravascular ultrasound is a safe and feasible imaging modality in patients with AMI and can help identify plaque rupture, intracoronary thrombus or calcification. The culprit lesion site in AMI cases often presents with positive remodeling.

  19. Co-doping of Ag into Mn:ZnSe Quantum Dots: Giving Optical Filtering effect with Improved Monochromaticity.

    Science.gov (United States)

    Hu, Zhiyang; Xu, Shuhong; Xu, Xiaojing; Wang, Zhaochong; Wang, Zhuyuan; Wang, Chunlei; Cui, Yiping

    2015-10-08

    In optics, when polychromatic light is filtered by an optical filter, the monochromaticity of the light can be improved. In this work, we reported that Ag dopant atoms could be used as an optical filter for nanosized Mn:ZnSe quantum dots (QDs). If no Ag doping, aqueous Mn:ZnSe QDs have low monochromaticity due to coexisting of strong ZnSe band gap emission, ZnSe trap emission, and Mn dopant emission. After doping of Ag into QDs, ZnSe band gap and ZnSe trap emissions can be filtered, leaving only Mn dopant emission with improved monochromaticity. The mechanism for the optical filtering effect of Ag was investigated. The results indicate that the doping of Ag will introduce a new faster deactivation process from ZnSe conduction band to Ag energy level, leading to less electrons deactived via ZnSe band gap emission and ZnSe trap emission. As a result, only Mn dopant emission is left.

  20. Improved Early Crop Type Identification By Joint Use of High Temporal Resolution SAR And Optical Image Time Series

    Directory of Open Access Journals (Sweden)

    Jordi Inglada

    2016-04-01

    Full Text Available High temporal and spatial resolution optical image time series have been proven efficient for crop type mapping at the end of the agricultural season. However, due to cloud cover and image availability, crop identification earlier in the season is difficult. The recent availability of high temporal and spatial resolution SAR image time series, opens the possibility of improving early crop type mapping. This paper studies the impact of such SAR image time series when used in complement of optical imagery. The pertinent SAR image features, the optimal working resolution, the effect of speckle filtering and the use of temporal gap-filling of the optical image time series are assessed. SAR image time series as those provided by the Sentinel-1 satellites allow significant improvements in terms of land cover classification, both in terms of accuracy at the end of the season and for early crop identification. Haralik textures (Entropy, Inertia, the polarization ratio and the local mean together with the VV imagery were found to be the most pertinent features. Working at at 10 m resolution and using speckle filtering yield better results than other configurations. Finally it was shown that the use of SAR imagery allows to use optical data without gap-filling yielding results which are equivalent to the use of gap-filling in the case of perfect cloud screening, and better results in the case of cloud screening errors.

  1. Supportive management strategies for disseminated intravascular coagulation. An international consensus.

    Science.gov (United States)

    Squizzato, Alessandro; Hunt, Beverley J; Kinasewitz, Gary T; Wada, Hideo; Ten Cate, Hugo; Thachil, Jecko; Levi, Marcel; Vicente, Vicente; D'Angelo, Armando; Di Nisio, Marcello

    2016-05-01

    The cornerstone of the management of disseminated intravascular coagulation (DIC) is the treatment of the underlying condition triggering the coagulopathy. However, a number of uncertainties remain over the optimal supportive treatment. The aim of this study was to provide evidence and expert-based recommendations on the optimal supportive haemostatic and antithrombotic treatment strategies for patients with DIC. A working group defined five relevant clinical scenarios. Published studies were systematically searched in the MEDLINE and EMBASE databases (up to May 2014). Seven internationally recognised experts were asked to independently provide clinical advice. A two-phase blinded data collection technique was used to reach consensus. Only three randomised controlled trials (RCTs) on the supportive management of DIC were identified. The RCTs (overall less than 100 patients) investigated the use of fresh frozen plasma and platelet transfusion and found no differences in survival between the intervention and control groups. The experts' approach was heterogeneous, although there was consensus that supportive management should vary according to the underlying cause, clinical manifestations and severity of blood test abnormalities. Platelet transfusion should be given to maintain platelet count > 50×10⁹/l in case of bleeding while a lower threshold of 20 to 30×10⁹/l may be used in DIC without bleeding. Thromboprophylaxis with low-molecular-weight heparin is advised until bleeding ensues or platelet count drops below 30×10⁹/l. In conclusion, in the absence of solid evidence from RCTs, an individualised supportive management of DIC is advisable based on the type of underlying disease, presence of bleeding or thrombotic complications and laboratory tests results.

  2. Monolithic CMUT-on-CMOS integration for intravascular ultrasound applications.

    Science.gov (United States)

    Zahorian, Jaime; Hochman, Michael; Xu, Toby; Satir, Sarp; Gurun, Gokce; Karaman, Mustafa; Degertekin, F Levent

    2011-12-01

    One of the most important promises of capacitive micromachined ultrasonic transducer (CMUT) technology is integration with electronics. This approach is required to minimize the parasitic capacitances in the receive mode, especially in catheter-based volumetric imaging arrays, for which the elements must be small. Furthermore, optimization of the available silicon area and minimized number of connections occurs when the CMUTs are fabricated directly above the associated electronics. Here, we describe successful fabrication and performance evaluation of CMUT arrays for intravascular imaging on custom-designed CMOS receiver electronics from a commercial IC foundry. The CMUT-on-CMOS process starts with surface isolation and mechanical planarization of the CMOS electronics to reduce topography. The rest of the CMUT fabrication is achieved by modifying a low-temperature micromachining process through the addition of a single mask and developing a dry etching step to produce sloped sidewalls for simple and reliable CMUT-to-CMOS interconnection. This CMUT-to-CMOS interconnect method reduced the parasitic capacitance by a factor of 200 when compared with a standard wire-bonding method. Characterization experiments indicate that the CMUT-on-CMOS elements are uniform in frequency response and are similar to CMUTs simultaneously fabricated on standard silicon wafers without electronics integration. Ex- periments on a 1.6-mm-diameter dual-ring CMUT array with a center frequency of 15 MHz show that both the CMUTs and the integrated CMOS electronics are fully functional. The SNR measurements indicate that the performance is adequate for imaging chronic total occlusions located 1 cm from the CMUT array.

  3. Intravascular papillary endothelial hyperplasia: magnetic resonance imaging of finger lesions

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Jinkyeong; Kim, Jee-Young [The Catholic University of Korea, Department of Radiology, St. Vincent' s Hospital, College of Medicine, Suwon, Gyeonggi-do (Korea, Republic of); Yoo, Changyoung [The Catholic University of Korea, Department of Hospital Pathology, St. Vincent' s Hospital, College of Medicine, Suwon, Gyeonggi-do (Korea, Republic of)

    2016-02-15

    To describe magnetic resonance imaging (MRI) features of intravascular papillary endothelial hyperplasia (IPEH), to identify findings differentiating IPEH of the finger from that of other locations, and to correlate these with pathology. Nineteen patients with 20 I.E. masses of the finger (n = 13) and other locations (n = 7) were evaluated. All patients underwent MRI, and the results were correlated with pathology. Seventeen IPEHs, including all IPEHs of the finger, were located in the subcutis, the three other lesions in the muscle layer. On T1WI, all masses were isointense or slightly hyperintense. IPEHs of the finger (n = 13) revealed focal hyperintense nodules (n = 2) or central hypointensity (n = 2) on T1WI, hypointensity with a hyperintense rim (n = 7), hyperintensity with hypointense nodules (n = 5), or isointensity with a hypointense rim (n = 1) on T2WI, and rim enhancement (n = 5), heterogeneous enhancement with nodular nonenhanced areas (n = 6), peripheral nodular enhancement (n = 1), or no enhancement (n = 1) on gadolinium-enhanced T1WI. IPEHs of other locations (n = 7) demonstrated focal hyperintense nodules (n = 5) on T1WI, hyperintensity with hypointense nodules (n = 5) or heterogeneous signal intensity (n = 2) on T2WI, and rim or rim and septal enhancement (n = 6) or peripheral nodular enhancement (n = 1). Microscopically, IPEHs were composed of thrombi that were hypointense on T2WI and papillary endothelial proliferations that showed T2 hyperintensity and enhancement. MRI of finger IPEH reveals well-demarcated subcutaneous masses with hypointensity or hypointense nodules with peripheral hyperintensity on T2WI, as well as peripheral enhancement. T1 hyperintense nodules, internal heterogeneity on T2WI, and septal enhancement are more common in IPEH of other locations. (orig.)

  4. Mechanotransductional basis of endothelial cell response to intravascular bubbles.

    Science.gov (United States)

    Klinger, Alexandra L; Pichette, Benjamin; Sobolewski, Peter; Eckmann, David M

    2011-10-01

    Vascular air embolism resulting from too rapid decompression is a well-known risk in deep-sea diving, aviation and space travel. It is also a common complication during surgery or other medical procedures when air or other endogenously administered gas is entrained in the circulation. Preventive and post-event treatment options are extremely limited for this dangerous condition, and none of them address the poorly understood pathophysiology of endothelial response to intravascular bubble presence. Using a novel apparatus allowing precise manipulation of microbubbles in real time fluorescence microscopy studies, we directly measure human umbilical vein endothelial cell responses to bubble contact. Strong intracellular calcium transients requiring extracellular calcium are observed upon cell-bubble interaction. The transient is eliminated both by the presence of the stretch activated channel inhibitor, gadolinium, and the transient receptor potential vanilliod family inhibitor, ruthenium red. No bubble induced calcium upsurge occurs if the cells are pretreated with an inhibitor of actin polymerization, cytochalasin-D. This study explores the biomechanical mechanisms at play in bubble interfacial interactions with endothelial surface layer (ESL) macromolecules, reassessing cell response after selective digestion of glycocalyx glycosoaminoglycans, hyaluran (HA) and heparin sulfate (HS). HA digestion causes reduction of cell-bubble adherence and a more rapid induction of calcium influx after contact. HS depletion significantly decreases calcium transient amplitudes, as does pharmacologically induced sydencan ectodomain shedding. The surfactant perfluorocarbon Oxycyte abolishes any bubble induced calcium transient, presumably through direct competition with ESL macromolecules for interfacial occupancy, thus attenuating the interactions that trigger potentially deleterious biochemical pathways.

  5. SEPSIS-ASSOCIATED DISSEMINATED INTRAVASCULAR COAGULATION AND THROMBOEMBOLIC DISEASE

    Directory of Open Access Journals (Sweden)

    Nicola Semeraro

    2010-08-01

    Full Text Available Sepsis is almost invariably associated with haemostatic abnormalities ranging from subclinical activation of blood coagulation (hypercoagulability, which may contribute to localized venous thromboembolism, to acute disseminated intravascular coagulation (DIC, characterized by massive thrombin formation and widespread microvascular thrombosis, partly responsible of the multiple organ dysfunction syndrome (MODS, and subsequent consumption of platelets and coagulation proteins causing, in most severe cases, bleeding manifestations. There is general agreement that the key event underlying this life-threatening sepsis complication is the overwhelming inflammatory host response to the infectious agent leading to the overexpression of inflammatory mediators. Mechanistically, the latter, together with the micro-organism and its derivatives, causes DIC by 1 up-regulation of procoagulant molecules, primarily tissue factor (TF, which is produced mainly by stimulated monocytes-macrophages and by specific cells in target tissues; 2 impairment of physiological anticoagulant pathways (antithrombin, protein C pathway, tissue factor pathway inhibitor, which is orchestrated mainly by dysfunctional endothelial cells (ECs; and 3 suppression of fibrinolysis due to increased plasminogen activator inhibitor-1 (PAI-1 by ECs and likely also to thrombin-mediated  activation of thrombin-activatable fibrinolysis inhibitor (TAFI. Notably, clotting enzymes non only lead to microvascular thrombosis but can also elicit cellular responses that amplify the inflammatory reactions. Inflammatory mediators can also cause, directly or indirectly, cell apoptosis or necrosis and recent evidence indicates that products released from dead cells, such as nuclear proteins (particularly extracellular histones, are able to propagate further inflammation, coagulation, cell death and MODS. These insights into the pathogenetic mechanisms of DIC and MODS may have important implications for the

  6. Intravascular ultrasound predictors of CD163 positive macrophage infiltration.

    Science.gov (United States)

    Sato, Takao; Kameyama, Tomoki; Ueno, Hiroshi; Inoue, Hiroshi

    2014-06-01

    The present study aimed to determine characteristics of macrophage accumulation and predictors of CD163 positive macrophages by ultrasonic tissue characterization. Intraplaque hemorrhage is associated with plaque instability and induces macrophage accumulation with a scavenger receptor, CD163. These CD163 positive macrophages have anti-atherogenic property. In 50 patients with acute coronary syndrome, lumen, vessel and plaque area, and plaque components (% fibrous, % fibro fatty, % dense calcium, and % necrotic core) of the culprit lesion were determined by virtual histology (VH) intravascular ultrasound (IVUS). Remodeling index (RI) was also determined. Atherothrombotic debris of the culprit lesion was collected during percutaneous coronary intervention using a distal protection device. CD163 positive macrophages and glycophorin A (a protein specific to erythrocytes) were determined immunohistochemically. Percentage of CD163 positive macrophages to the whole cells (% CD163) correlated positively with lumen, vessel and plaque area, and RI. Further, % CD163 had significant positive correlation with % necrotic core and negative correlation with % dense calcium. Immunopositive areas of glycophorin A (% glycophorin A), expressed as the ratio of positively stained areas per total tissue, had a significant positive correlation with % CD163. On multivariate analysis, % necrotic core, % dense calcium, and RI were independent determinants of % CD163. Positive remodeling and large necrotic core without calcification on VH-IVUS were likely to indicate coronary intraplaque hemorrhage with CD163 positive macrophages infiltration. © 2014, Wiley Periodicals, Inc.

  7. Successful Control of Disseminated Intravascular Coagulation by Recombinant Thrombomodulin during Arsenic Trioxide Treatment in Relapsed Patient with Acute Promyelocytic Leukemia

    Directory of Open Access Journals (Sweden)

    Motohiro Shindo

    2012-01-01

    Full Text Available Disseminated intravascular coagulation (DIC frequently occurs in patients with acute promyelocytic leukemia (APL. With the induction of therapy in APL using all-trans retinoic acid (ATRA, DIC can be controlled in most cases as ATRA usually shows immediate improvement of the APL. However, arsenic trioxide (ATO which has been used for the treatment of relapse in APL patients has shown to take time to suppress APL cells, therefore the control of DIC in APL with ATO treatment is a major problem. Recently, the recombinant soluble thrombomodulin fragment has received a lot of attention as the novel drug for the treatment of DIC with high efficacy. Here, we present a relapsed patient with APL in whom DIC was successfully and safely controlled by rTM during treatment with ATO.

  8. Strategies to Improve the Accuracy of Mars-GRAM Sensitivity Studies at Large Optical Depths

    Science.gov (United States)

    Justh, Hilary L.; Justus, Carl G.; Badger, Andrew M.

    2009-01-01

    at comparable dust loading. Currently, these density factors are fixed values for all latitudes and Ls. Results will be presented of the work underway to derive better multipliers by including possible variation with latitude and/or Ls. This is achieved by comparison of Mars-GRAM MapYear=0 output with TES limb data. The addition of these density factors to Mars-GRAM will improve the results of the sensitivity studies done for large optical depths. Answers may also be provided to the issues raised in a recent study by Desai(2008). Desai has shown that the actual landing sites of Mars Pathfinder, the Mars Exploration Rovers and the Phoenix Mars Lander have been further downrange than predicted by models prior to landing. Desai s reconstruction of their entries into the Martian atmosphere showed that the models consistently predicted higher densities than those found upon EDL. The solution of this problem would be important to the Mars Program since future exploration of Mars by landers and rovers will require more accurate landing capabilities, especially for the proposed Mars Sample Return mission.

  9. Fabrication of a porous fiber cladding material using microsphere templating for improved response time with fiber optic sensor arrays.

    Science.gov (United States)

    Henning, Paul E; Rigo, M Veronica; Geissinger, Peter

    2012-01-01

    A highly porous optical-fiber cladding was developed for evanescent-wave fiber sensors, which contains sensor molecules, maintains guiding conditions in the optical fiber, and is suitable for sensing in aqueous environments. To make the cladding material (a poly(ethylene) glycol diacrylate (PEGDA) polymer) highly porous, a microsphere templating strategy was employed. The resulting pore network increases transport of the target analyte to the sensor molecules located in the cladding, which improves the sensor response time. This was demonstrated using fluorescein-based pH sensor molecules, which were covalently attached to the cladding material. Scanning electron microscopy was used to examine the structure of the templated polymer and the large network of interconnected pores. Fluorescence measurements showed a tenfold improvement in the response time for the templated polymer and a reliable pH response over a pH range of five to nine with an estimated accuracy of 0.08 pH units.

  10. Teleophthalmology with optical coherence tomography imaging in community optometry. Evaluation of a quality improvement for macular patients

    Directory of Open Access Journals (Sweden)

    Kelly SP

    2011-12-01

    Full Text Available Simon P Kelly1, Ian Wallwork2, David Haider1, Kashif Qureshi11Ophthalmology Department, Royal Bolton Hospital National Health Service Foundation Trust, Bolton, 2Wallwork Opticians, Salford, UKPurpose: To describe a quality improvement for referral of National Health Service patients with macular disorders from a community optometry setting in an urban area.Methods: Service evaluation of teleophthalmology consultation based on spectral domain optical coherence tomography images acquired by the community optometrist and transmitted to hospital eye services.Results: Fifty patients with suspected macular conditions were managed via telemedicine consultation over 1 year. Responses were provided by hospital eye service-based ophthalmologists to the community optometrist or patient within the next day in 48 cases (96% and in 34 (68% patients on the same day. In the consensus opinion of the optometrist and ophthalmologist, 33 (66% patients required further “face-to-face” medical examination and were triaged on clinical urgency. Seventeen cases (34% were managed in the community and are a potential cost improvement. Specialty trainees were supervised in telemedicine consultations.Conclusion: Innovation and quality improvement were demonstrated in both optometry to ophthalmology referrals and in primary optometric care by use of telemedicine with spectral domain optical coherence tomography images. E-referral of spectral domain optical coherence tomography images assists triage of macular patients and swifter care of urgent cases. Teleophthalmology is also, in the authors’ opinion, a tool to improve interdisciplinary professional working with community optometrists. Implications for progress are discussed.Keywords: telemedicine, teleophthalmology, innovation, community referral, optical coherence tomography, service evaluation

  11. Severe bleeding tendency caused by a rare complication of excessive fibrinolysis with disseminated intravascular coagulation in a 51-year-old Japanese man with prostate cancer: a case report

    Directory of Open Access Journals (Sweden)

    Wada Yoshihiro

    2012-11-01

    Full Text Available Abstract Introduction Disseminated intravascular coagulation causes thrombotic tendency leading to multiple organ failure and occurs in a wide variety of diseases including malignancy. Disseminated intravascular coagulation is a latent complication in people with prostate cancer. Case presentation A 51-year-old Japanese man with advanced castration-resistant prostate cancer was admitted to our hospital because of extensive purpura and severe anemia. Prolonged plasma coagulation time, hypofibrinogenemia and normal platelet count suggested that a decrease in fibrinogen induced a bleeding tendency causing purpura. However, elevated plasma levels of thrombin-antithrombin complex, fibrin and/or fibrinogen degradation products and D-dimers, with positive fibrin monomer test, manifested disseminated intravascular coagulation and subsequent fibrinolysis. Plasma levels of thrombin-antithrombin complex, fibrin and/or fibrinogen degradation products and D-dimers decreased after administration of low-molecular-weight heparin. However, low fibrinogen and α2-antiplasmin levels were not improved and plasmin-antiplasmin complex did not decrease, which revealed excessive fibrinolysis complicated with disseminated intravascular coagulation. We suspected that prostate cancer cell-derived urokinase-type plasminogen activator caused excessive fibrinolysis. Administration of tranexamic acid for fibrinogenolysis was added together with high-dose anti-androgen therapy (fosfestrol for prostate cancer. Thereafter, prostate-specific antigen and plasmin-antiplasmin complex decreased, followed by normalized fibrinogen and α2-antiplasmin levels, and the patient eventually recovered from the bleeding tendency. Immunohistochemical staining of the biopsied prostate tissue exhibited that the prostate cancer cells produced tissue factor, the coagulation initiator, and urokinase-type plasminogen activator. Conclusion This patient with rare complications of disseminated

  12. Improvement of Aerosol Optical Depth Retrieval over Hong Kong from a Geostationary Meteorological Satellite Using Critical Reflectance with Background Optical Depth Correction

    Science.gov (United States)

    Kim, Mijin; Kim, Jhoon; Wong, Man Sing; Yoon, Jongmin; Lee, Jaehwa; Wu, Dong L.; Chan, P.W.; Nichol, Janet E.; Chung, Chu-Yong; Ou, Mi-Lim

    2014-01-01

    Despite continuous efforts to retrieve aerosol optical depth (AOD) using a conventional 5-channelmeteorological imager in geostationary orbit, the accuracy in urban areas has been poorer than other areas primarily due to complex urban surface properties and mixed aerosol types from different emission sources. The two largest error sources in aerosol retrieval have been aerosol type selection and surface reflectance. In selecting the aerosol type from a single visible channel, the season-dependent aerosol optical properties were adopted from longterm measurements of Aerosol Robotic Network (AERONET) sun-photometers. With the aerosol optical properties obtained fromthe AERONET inversion data, look-up tableswere calculated by using a radiative transfer code: the Second Simulation of the Satellite Signal in the Solar Spectrum (6S). Surface reflectance was estimated using the clear sky composite method, awidely used technique for geostationary retrievals. Over East Asia, the AOD retrieved from the Meteorological Imager showed good agreement, although the values were affected by cloud contamination errors. However, the conventional retrieval of the AOD over Hong Kong was largely underestimated due to the lack of information on the aerosol type and surface properties. To detect spatial and temporal variation of aerosol type over the area, the critical reflectance method, a technique to retrieve single scattering albedo (SSA), was applied. Additionally, the background aerosol effect was corrected to improve the accuracy of the surface reflectance over Hong Kong. The AOD retrieved froma modified algorithmwas compared to the collocated data measured by AERONET in Hong Kong. The comparison showed that the new aerosol type selection using the critical reflectance and the corrected surface reflectance significantly improved the accuracy of AODs in Hong Kong areas,with a correlation coefficient increase from0.65 to 0.76 and a regression line change from tMI [basic algorithm] = 0

  13. A case of giant cavernous hemangioma of the liver complicated by intravascular coagulopathy.

    Directory of Open Access Journals (Sweden)

    Watanabe,Makoto

    1978-04-01

    Full Text Available A case of liver hemangioma complicated by intravascular coagulopathy is presented because of the rarity of the association. Hemangioma of the liver was suspected by palpation of the liver tumor, scintigraphy and x-ray examination, and confirmed by selective hepatic arteriography in combination with exploratory laparotomy. Intravascular coagulopathy was established by demonstrating secondary fibrinolysis and consumption of platelets and coagulation factors. Unconjugated hyperbilirubinemia due to micro-angiopathic hemolytic anemia was also present. The clinical course of the clotting abnormalities was basically a chronic one with an occasional acute or subacute defibrination process associated with further enlargement of the hepatic tumor. These provide sufficient evidence that the intravascular coagulopathy was closely related with the hemangioma in the liver. Neither ligation of a presumed nutritional artery of the hemangioma nor radiation therapy caused any demonstrable reduction in the tumor size.

  14. Intravascular large B-cell lymphoma presenting clinically as rapidly progressive dementia.

    Science.gov (United States)

    Brett, F M; Chen, D; Loftus, T; Langan, Y; Looby, S; Hutchinson, S

    2017-07-19

    In patients presenting with rapidly progressive dementia, prion disease may enter the differential diagnosis. The commonest malignancies masquerading as prion disease are primary CNS lymphoma and intravascular large B-cell lymphoma, both rare and difficult to diagnose without brain biopsy. This 82-year-old lady with a past history of hypertension, presented with rapidly progressive cognitive impairment and ataxia. The possibility of sCJD was raised. Brain biopsy was carried out. Western blot for prion protein was negative. Brain biopsy showed intravascular large B-cell lymphoma. She died shortly afterwards. The clinical presentation of intravascular large B-cell lymphoma is diverse. Patients may present as in this case with dementia, seizures, and myoclonus leading to a clinical diagnosis of sCJD. The diagnosis here was made at biopsy but is made at autopsy in over 50% of cases.

  15. Intravascular lymphoma presenting as a specific pulmonary embolism and acute respiratory failure: a case report

    Directory of Open Access Journals (Sweden)

    Georgin-Lavialle Sophie

    2009-05-01

    Full Text Available Abstract Introduction The occurrence of an intravascular lymphoma with severe pulmonary involvement mimicking pulmonary embolism is described. Case presentation A 38-year-old man was referred to our intensive care unit with acute respiratory failure and long lasting fever. Appropriate investigations failed to demonstrate any bacterial, viral, parasitic or mycobacterial infection. A chest computed tomography scan ruled out any proximal or sub-segmental pulmonary embolism but the ventilation/perfusion lung scan concluded that there was a high probability of pulmonary embolism. The cutaneous biopsy pathology diagnosed intravascular lymphoma. Conclusion Intravascular lymphoma is a rare disease characterized by exclusive or predominant growth of neoplastic cells within the lumina of small blood vessels. Lung involvement seems to be common, but predominant lung presentation of this disease is rare. In our patient, urgent chemotherapy, along with adequate supportive care allowed complete recovery.

  16. An improved algorithm for the determination of aerosol optical depth in the ultraviolet spectral range from Brewer spectrophotometer observations

    Science.gov (United States)

    Sellitto, P.; di Sarra, A.; Siani, A. M.

    2006-10-01

    Methods to derive aerosol optical depth in the UV spectral range from ground-based remote-sensing stations equipped with Brewer spectrophotometers have been recently developed. In this study a modified Langley plot method has been implemented to retrieve aerosol optical depth from direct sun Brewer measurements. The method uses measurements over an extended range of atmospheric airmasses obtained with two different neutral density filters, and accounts for short-term variations of total ozone, derived from the same direct sun observations. The improved algorithm has been applied to data collected with a Brewer mark IV, operational in Rome, Italy, and with a Brewer mark III, operational in Lampedusa, Italy, in the Mediterranean. The efficiency of the improved algorithm has been tested comparing the number of determinations of the extraterrestrial constant against those obtained with a standard Langley plot procedure. The improved method produces a larger number of reliable Langley plots, allowing for a better statistical characterization of the extraterrestrial constant and a better study of its temporal variability. The values of aerosol optical depth calculated in Rome and Lampedusa compare well with simultaneous determinations in the 416-440 nm interval derived from MFRSR and CIMEL measurements.

  17. Accumulation of /sup 99m/Tc-sulfur colloid by the lung and kidney following disseminated intravascular coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Smith, F.W.; Brown, R.G.; Ash, J.M.; Gilday, D.L.

    1980-06-01

    A patient is described who demonstrated accumulation of /sup 99m/Tc-sulfur colloid in both the lung and kidney following treatment for disseminated intravascular coagulation. This phenomenon has been demonstrated experimentally in animals following the induction of disseminated intravascular coagulation, but to our knowledge has not been previously described in humans.

  18. Improved performance of traveling wave directional coupler modulator based on electro-optic polymer

    CERN Document Server

    Zhang, Xingyu; Lin, Che-yun; Wang, Alan X; Hosseini, Amir; Lin, Xiaohui; Chen, Ray T

    2014-01-01

    Polymer based electro-optic modulators have shown great potentials in high frequency analog optical links. Existing commercial LiNibO3 Mach-Zehnder modulators have intrinsic drawbacks in linearity to provide high fidelity communication. In this paper, we present the design, fabrication and characterization of a traveling wave directional coupler modulator based on electro-optic polymer, which is able to provide high linearity, high speed, and low optical insertion loss. A silver ground electrode is used to reduce waveguide sidewall roughness due to the scattering of UV light in photolithography process in addition to suppressing the RF loss. A 1-to-2 multi-mode interference 3dB-splitter, a photobleached refractive index taper and a quasi-vertical taper are used to reduce the optical insertion loss of the device. The symmetric waveguide structure of the MMI-fed directional coupler is intrinsically bias-free, and the modulation is obtained at the 3-dB point regardless of the ambient temperature. By achieving lo...

  19. Improving depth resolution of diffuse optical tomography with an exponential adjustment method based on maximum singular value of layered sensitivity

    Institute of Scientific and Technical Information of China (English)

    Haijing Niu; Ping Guo; Xiaodong Song; Tianzi Jiang

    2008-01-01

    The sensitivity of diffuse optical tomography (DOT) imaging exponentially decreases with the increase of photon penetration depth, which leads to a poor depth resolution for DOT. In this letter, an exponential adjustment method (EAM) based on maximum singular value of layered sensitivity is proposed. Optimal depth resolution can be achieved by compensating the reduced sensitivity in the deep medium. Simulations are performed using a semi-infinite model and the simulation results show that the EAM method can substantially improve the depth resolution of deeply embedded objects in the medium. Consequently, the image quality and the reconstruction accuracy for these objects have been largely improved.

  20. Performance of an improved first generation optical CT scanner for 3D dosimetry.

    Science.gov (United States)

    Qian, Xin; Adamovics, John; Wuu, Cheng-Shie

    2013-12-21

    Performance analysis of a modified 3D dosimetry optical scanner based on the first generation optical CT scanner OCTOPUS is presented. The system consists of PRESAGE dosimeters, the modified 3D scanner, and a new developed in-house user control panel written in Labview program which provides more flexibility to optimize mechanical control and data acquisition technique. The total scanning time has been significantly reduced from initial 8 h to ∼2 h by using the modified scanner. The functional performance of the modified scanner has been evaluated in terms of the mechanical integrity uncertainty of the data acquisition process. Optical density distribution comparison between the modified scanner, OCTOPUS and the treatment plan system has been studied. It has been demonstrated that the agreement between the modified scanner and treatment plans is comparable with that between the OCTOPUS and treatment plans.

  1. An improved optical tweezers assay for measuring the force generation of single kinesin molecules.

    Science.gov (United States)

    Nicholas, Matthew P; Rao, Lu; Gennerich, Arne

    2014-01-01

    Numerous microtubule-associated molecular motors, including several kinesins and cytoplasmic dynein, produce opposing forces that regulate spindle and chromosome positioning during mitosis. The motility and force generation of these motors are therefore critical to normal cell division, and dysfunction of these processes may contribute to human disease. Optical tweezers provide a powerful method for studying the nanometer motility and piconewton force generation of single motor proteins in vitro. Using kinesin-1 as a prototype, we present a set of step-by-step, optimized protocols for expressing a kinesin construct (K560-GFP) in Escherichia coli, purifying it, and studying its force generation in an optical tweezers microscope. We also provide detailed instructions on proper alignment and calibration of an optical trapping microscope. These methods provide a foundation for a variety of similar experiments.

  2. Recent acquisitions in the pathophysiology, diagnosis and treatment of disseminated intravascular coagulation

    Directory of Open Access Journals (Sweden)

    Lippi Giuseppe

    2006-02-01

    Full Text Available Abstract Disseminated intravascular coagulation (DIC is a disorder characterized by both acute generalized, widespread activation of coagulation, which results in thrombotic complications due to the intravascular formation of fibrin, and diffuse hemorrhages, due to the consumption of platelets and coagulation factors. Systemic activation of coagulation may occur in a variety of disorders, including sepsis, severe infections, malignancies, obstetric or vascular disorders, and severe toxic or immunological reactions. In this review, we briefly report the present knowledge about the pathophysiology and diagnosis of DIC. Particular attention is also given to the current standard and experimental therapies of overt DIC.

  3. Intravascular ultrasound-guided stenting of left main stem dissection after Medtronic Corevalve implantation.

    Science.gov (United States)

    Van Mieghem, N M; de Jaegere, P P

    2013-08-01

    Transcatheter aortic valve implantation (TAVI) implies the introduction, positioning, and deployment of a stented bioprosthesis in the (calcified) native aortic valve. We report an at first glance uneventful TAVI with the Medtronic Corevalve System, which was followed by transient electrocardiographic changes suggesting acute left main stem disease. The diagnosis of acute left main stem dissection extending from the left coronary cusp was firmly established by intravascular ultrasound. The ostium of the left main stem was successfully treated with intravascular ultrasound-guided placement of a drug eluting stent. © 2013 Wiley Periodicals, Inc.

  4. Early thrombomodulin-α administration outcome for acute disseminated intravascular coagulopathy in gastrointestinal surgery.

    Science.gov (United States)

    Konishi, Hirotaka; Okamoto, Kazuma; Shoda, Katsutoshi; Arita, Tomohiro; Kosuga, Toshiyuki; Morimura, Ryo; Komatsu, Shuhei; Murayama, Yasutoshi; Shiozaki, Atsushi; Kuriu, Yoshiaki; Ikoma, Hisashi; Nakanishi, Masayoshi; Ichikawa, Daisuke; Fujiwara, Hitoshi; Otsuji, Eigo

    2017-02-07

    To investigate the efficacy of thrombomodulin (TM)-α for treatment of disseminated intravascular coagulopathy (DIC) in the field of gastrointestinal surgery. Thirty-six peri-operative DIC patients in the field of gastrointestinal surgery who were treated with TM-α were retrospectively investigated. The relationships between patient demographics and the efficacy of TM-α were examined. Analysis of survival at 28 d was also performed on some parameters by means of the Kaplan-Meier method. Relationships between the initiation of TM-α and patient demographics were also evaluated. Abscess formation or bacteremia was the most frequent cause of DIC (33%), followed by digestive tract perforation (31%). Twenty-six patients developed DIC after surgery, frequently within 1 wk (81%). TM-α was most often administered within 1 d of the DIC diagnosis (72%) and was continued for more than 3 d (64%). Although bleeding tendency was observed in 7 patients (19%), a hemostatic procedure was not needed. DIC scores, systemic inflammatory response syndrome (SIRS) scores, quick-sequential organ failure assessment (qSOFA) scores, platelet counts, and prothrombin time ratios significantly improved after 1 wk (P SIRS and qSOFA) at 1 wk were significantly better prognostic factors for 28-d survival (P < 0.05, for all). TM-α was administered significantly earlier to patients with severe clinical symptoms, such as high qSOFA scores, sepsis, shock or high lactate values (P < 0.05, for all). Early administration of TM-α and improvements in each parameter were essential for treatment of DIC. The diagnosis of patients with mild symptoms requires further study.

  5. Exogenous normal lymph alleviates microcirculation disturbances and abnormal hemorheological properties in rats with disseminated intravascular coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Chun-Yu; Zhao, Zi-Gang; Zhang, Yu-Ping [Institute of Microcirculation, Hebei North University, Zhangjiakou (China); Hou, Ya-Li [Department of Clinical Laboratory, First Affiliated Hospital, Hebei North University, Zhangjiakou (China); Li, Jun-Jie; Jiang, Hua; Zhang, Jing [Institute of Microcirculation, Hebei North University, Zhangjiakou (China)

    2013-02-01

    Disturbances of the microcirculation and abnormal hemorheological properties are important factors that play an important role in disseminated intravascular coagulation (DIC) and result in organ dysfunction or failure. In the present study, we established an animal model of DIC using intravenous Dextran 500 in rats, and used exogenous normal lymph corresponding to 1/15 of whole blood volume for injection through the left jugular vein. We found that normal lymph could improve the blood pressure and survival time of rats with DIC. The results regarding the mesenteric microcirculation showed that the abnormality of the diameter of mesenteric microvessels and micro-blood flow speed in the DIC+lymph group was significantly less than in the DIC+saline group. Whole blood viscosity, relative viscosity, plasma viscosity, hematocrit (Hct), erythrocyte sedimentation rate (ESR), and electrophoresis time of erythrocytes were significantly increased in the DIC+saline group compared to the control group. The electrophoretic length and migration of erythrocytes from the DIC+saline and DIC+lymph groups were significantly slower than the control group. Blood relative viscosity, Hct, ESR, and electrophoretic time of erythrocytes were significantly increased in the DIC+lymph group compared to the control group. Whole blood viscosity, relative viscosity and reduced viscosity were significantly lower in the DIC+lymph group than in the DIC+saline group, and erythrocyte deformability index was also significantly higher than in the DIC+saline and control groups. These results suggest that exogenous normal lymph could markedly improve the acute microcirculation disturbance and the abnormal hemorheological properties in rats with DIC induced by Dextran 500.

  6. IMPACT OF OBESITY ON ENDOTOXIN-INDUCED DISSEMINATED INTRAVASCULAR COAGULATION.

    Science.gov (United States)

    Duburcq, Thibault; Tournoys, Antoine; Gnemmi, Viviane; Hubert, Thomas; Gmyr, Valery; Pattou, François; Jourdain, Mercé

    2015-10-01

    An early activation of coagulation and fibrinolysis occurs during sepsis, leading to the syndrome of disseminated intravascular coagulation (DIC). Obesity has been demonstrated to be a hypercoagulable and hypofibrinolytic state, but its impact on DIC has never been studied. In this study, we aimed to determine if obesity impairs DIC in an acute endotoxic shock model using minipigs. This was a prospective, comparative, and experimental ancillary study approved by the Animal Ethics Committee. Pigs were chosen as a clinically relevant species, resembling humans in coagulation reactions. Four groups of five "Yucatan" minipigs were studied: lean and obese control groups, a lean lipopolysaccharide (LPS) group receiving Escherichia coli endotoxin (LPS), and an obese LPS group receiving the same endotoxin dose. We measured standard coagulation parameters (prothrombin time [PT], platelet count, and fibrinogen levels), thrombin-antithrombin complexes, tissue-type plasminogen activator, and plasminogen activator inhibitor-1. All measurements were performed at baseline and 30, 60, 90, 150, and 300 min. Results were given as median with interquartile ranges. At baseline, platelet count (477 [428 - 532] G/L vs. 381 [307 - 442] G/L; P = 0.005) and fibrinogen levels (4.6 [3.8 - 5.2] g/L vs. 2 [1.8 - 2.9] g/L; P coagulation parameters (PT, platelet count, and fibrinogen levels) and the increase in thrombin-antithrombin complexes (581 [382 - 1,057] μg/mL vs. 247 [125 - 369] μg/mL at 150 min; P = 0.03) were significantly more important in the obese LPS group compared with those in the lean LPS group. Concerning the fibrinolytic reaction, we found a slightly more elevated increase of plasminogen activator inhibitor-1 in the obese LPS group at 300 min (481 [365 - 617] ng/mL vs. 355 [209 - 660] ng/mL; P = 0.66). In our model of endotoxic shock, obese pigs developed a more severe DIC with a more severe procoagulant response.

  7. Intravascular Ultrasound in Percutaneous Coronary Intervention for Chronic Total Occlusion

    Directory of Open Access Journals (Sweden)

    M Mohandes

    2010-09-01

    Full Text Available Background: Percutaneous coronary intervention (PCI of chronic total occlusion (CTO is one of the most challenging procedures in interventional cardiology. New techniques and devices have made possible to face these complex procedures. Intravascular ultrasound (IVUS reveals special features and contributes greatly to procedural success.Method: We analysed retrospectively IVUS contribution and findings in 23 cases of a total 46 CTOs PCI from February 2009 to August 2010 in our cath lab. Both true and functional CTO were included in this study. The procedure was considered successful when a TIMI III flow was reached in the occluded vessel after stent implantation with a residual stenosis less than 30%. IVUS features and contribution in CTO-PCI were analysed. All data were introduced in SPSS version 15 (SPSS Inc. Chicago, Illinois, USA. Continuous variables were described by mean ± SD and categorical variables were expressed as percentage. A P<0.05 was considered statistically significant.Results: 46 PCIs in 34 patients were performed during 19 months in our centre. The procedure was successful in 28 cases (60.9%.. IVUS was performed in 23 (82.1% of successful procedures. IVUS revealed calcium somewhere in 17 (73.9%. Despite wire angiographic verification in true lumen distally IVUS showed subintimal wire position in part of CTO segment in 6(26.1%. In 22(95.7% of cases IVUS allowed both the wire position verification in true lumen and the vessel measurement before stent implantation. In 1(4.3% case a second wire was introduced into true lumen guided by IVUS after realising that the first wire was in false lumen. We could not find significant relation between calcium presence and subintimal wire penetration in CTO segment (p: 0.14 Conclusions: IVUS showed calcium in CTO segment in a high percentage of cases. It is not unusual to find wire penetration in subintimal space in part of CTO segment. IVUS has a key contribution in the step by step

  8. Rifampicin-induced disseminated intravascular coagulation in pulmonary tuberculosis treatment

    Science.gov (United States)

    Chen, Guo; He, Jian-Qing

    2017-01-01

    Abstract Rationale: Disseminated intravascular coagulation (DIC) induced by daily rifampicin therapy is rare, especially the patient is absent of malignancy, severe infection, and prior exposure to rifampicin. Patient concerns: We report a case of DIC induced by daily rifampicin treatment for pulmonary tuberculosis. A 22-year-old, previously healthy man received an anti-tuberculosis therapy consisting of isoniazid, rifampicin, ethambutol, and pyrazinamide on the daily dose recommended by the World Health Organization tuberculosis guidelines after a diagnosis of pulmonary tuberculosis. Two weeks later, he was transferred to the West China Hospital with nasal hemorrhage for 1 week, hematochezia, hematuria, and petechiae for 5 days. Diagnoses: Laboratory data and symptoms on admission indicated DIC. Interventions: The anti-tuberculosis drugs were discontinued after admission and he was initiated with targeted treatment for DIC, omeprazole and polyene hosphatidylcholine infusion, as well as nutrition supportive treatment. Five days after admission, ethambutol, moxifloxacin, and amikacin were added to the patient without further active hemorrhage. Eight days after admission, the platelet count had risen gradually. Isoniazid was administered on 24 days after admission, while his liver function tests and platelet counts returned to normal. No recurrence of DIC occurred. The diagnosis of rifampicin-induced DIC was confirmed. Outcomes: The patient recovered and left hospital with isoniazid, ethambutol, levofloxacin, and streptomycin after 4 weeks of hospitalization. There was no recurrence of DIC or hemorrhage during the 8 months of follow-up. The literature review revealed that there were 10 other cases of rifampicin-induced DIC. Only 4 cases received rifampicin on a daily basis for pulmonary tuberculosis treatment and the others were on intermittent dosing schedule for pulmonary tuberculosis or leprosy treatment. Lessons: As a rare adverse effect, DIC induced by

  9. Multicenter evaluation of temporary intravascular shunt use in vascular trauma.

    Science.gov (United States)

    Inaba, Kenji; Aksoy, Hande; Seamon, Mark J; Marks, Joshua A; Duchesne, Juan; Schroll, Rebecca; Fox, Charles J; Pieracci, Fredric M; Moore, Ernest E; Joseph, Bellal; Haider, Ansab A; Harvin, John A; Lawless, Ryan A; Cannon, Jeremy; Holland, Seth R; Demetriades, Demetrios

    2016-03-01

    The indications and outcomes associated with temporary intravascular shunting (TIVS) for vascular trauma in the civilian sector are poorly understood. The objective of this study was to perform a contemporary multicenter review of TIVS use and outcomes. Patients sustaining vascular trauma, requiring TIVS insertion (January 2005 to December 2013), were retrospectively identified at seven Level I trauma centers. Clinical demographics, operative details, and outcomes were abstracted. A total of 213 injuries (2.7%; 94.8% arterial) requiring TIVS were identified in 7,385 patients with vascular injuries. Median age was 27.0 years (range, 4-89 years), 91.0% were male, Glasgow Coma Scale (GCS) score was 15.0 (interquartile range, 4.0), Injury Severity Score (ISS) was 16.0 (interquartile range, 15.0), 26.0% had an ISS of 25 or greater, and 71.1% had penetrating injuries. The most common mechanism was gunshot wound (62.7%), followed by auto versus pedestrian (11.4%) and motor vehicle collision (6.5%). Shunts were placed for damage control in 63.4%, staged repair for combined orthopedic and vascular injuries in 36.1%, and for insufficient surgeon skill set in 0.5%. The most common vessel shunted was the superficial femoral artery (23.9%), followed by popliteal artery (18.8%) and brachial artery (13.2%). An argyle shunt (81.2%) was the most common conduit, followed by Pruitt-Inahara (9.4%). Dwell time was less than 6 hours in 61.4%, 24 hours in 86.5%, 48 hours in 95.9%, with only 4.1% remaining in place for more than 48 hours. Of the patients, 81.6% survived to definitive repair, and 79.6% survived overall. Complications included shunt thrombosis (5.6%) and dislodgment (1.4%). There was no association between dwell time and shunt thrombosis. The use of a noncommercial shunt (chest tube/feeding tube) did not impact shunt thrombosis but was an independent risk factor for subsequent graft failure. The limb salvage rate was 96.3%. No deaths could be attributed to a shunt

  10. Surface Contaminant Control Technologies to Improve Laser Damage Resistance of Optics

    Directory of Open Access Journals (Sweden)

    Xiaofeng Cheng

    2014-01-01

    Full Text Available The large high-power solid lasers, such as the National Ignition Facility (NIF of America and the Shenguang-III (SG-III laser facility of China, can output over 2.1 MJ laser pulse for the inertial confinement fusion (ICF experiments. Because of the enhancement of operating flux and the expansion of laser driver scale, the problem of contamination seriously influences their construction period and operation life. During irradiation by intense laser beams, the contaminants on the metallic surface of beam tubes can be transmitted to the optical surfaces and lead to damage of optical components. For the high-power solid-state laser facilities, contamination control focuses on the slab amplifiers, spatial filters, and final-optical assemblies. In this paper, an effective solution to control contaminations including the whole process of the laser driver is put forward to provide the safe operation of laser facilities, and the detailed technical methods of contamination control such as washing, cleanliness metrology, and cleanliness protecting are also introduced to reduce the probability of laser-induced damage of optics. The experimental results show that the cleanliness level of SG-III laser facility is much better to ensure that the laser facility can safely operate at high energy flux.

  11. Improving the acousto-optical interaction in a Mach-Zehnder interferometer

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Sigmund, Ole

    2009-01-01

    A method for modeling the interaction of the mechanical field from a surface acoustic wave and the optical field in the waveguides of a Mach–Zehnder interferometer is presented. The surface acoustic wave is generated by an interdigital transducer using a linear elastic plane model of a piezoelect......A method for modeling the interaction of the mechanical field from a surface acoustic wave and the optical field in the waveguides of a Mach–Zehnder interferometer is presented. The surface acoustic wave is generated by an interdigital transducer using a linear elastic plane model...... of a piezoelectric, inhomogeneous material, and reflections from the boundaries are avoided by applying perfectly matched layers. The optical modes in the waveguides are modeled by time-harmonic wave equations for the magnetic field. The two models are coupled using stress-optical relations and the change...... bigger if the waveguides are kept single moded. It is furthermore shown that the difference increases more than ten times when the waveguides are buried below the surface, where the mechanical stresses have their maximum, and in the case where two interdigital transducers are used the difference...

  12. Improved characterisation of intra-night optical variability of prominent AGN classes

    CERN Document Server

    Goyal, Arti; Wiita, Paul J; Stalin, C S; Sagar, Ram

    2013-01-01

    The incidence of intra-night optical variability (INOV) is known to to differ significantly among different classes of powerful active galactic nuclei (AGN). A number of statistical methods have been employed in the literature for testing the presence of INOV in the light curves, sometimes leading to discordant results. In this paper we compare the INOV characteristics of six prominent classes of AGN, as evaluated using three commonly used statistical tests, namely the $\\chi^2-$test, the modified $C-$test and the $F-$test, which has recently begun to gain popularity. The AGN classes considered are: radio-quiet quasars (RQQs), radio-intermediate quasars (RIQs), lobe-dominated quasars (LDQs), low optical polarization core-dominated quasars (LPCDQs), high optical polarization core-dominated quasars (HPCDQs), and TeV blazars. Our analysis is based on a large body of AGN monitoring data, involving 262 sessions of intra-night monitoring of a total 77 AGN, using 1-2 metre class optical telescopes located in India. I...

  13. Improved thermal and strain performance of annealed polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bache, Morten;

    2011-01-01

    We report on a detailed study of the inscription and characterization of fiber Bragg gratings (FBGs) in commercial step index polymer optical fibers (POFs). Through the growth dynamics of the gratings, we identify the effect of UV-induced heating during the grating inscription. We found that FBGs...

  14. Analysis and optimization of radial smoothing based on optical Kerr effect for irradiation improvement

    Science.gov (United States)

    Hou, Pengcheng; Zhong, Zheqiang; Zhang, Bin

    2016-11-01

    In radial smoothing scheme, taking a super-Gaussian pulse train obtained by the pulse stacking scheme based on fibers and spatial shaping technology based on serrated-aperture apodizers as the pump laser, due to the hemispherical shape of the optical Kerr medium, the induced refraction index by the interaction of the optical Kerr medium and the pump laser is spherically distributed with periodical variation. Consequently, the transmission wavefront of the laser quads in the beamline is periodically modulated, resulting in the rapidly and periodic focal zooming in far field. This focal zooming smoothes the speckles on target plane in the radial direction in the sense of averaged over a finite time interval. The performance of the pump laser and the optical Kerr medium strongly affect the radial smoothing effect. In order to obtain better smoothing effect as that of smoothing by spectral dispersion, the propagation model of laser quads in the beamline with the radial smoothing scheme has been built up and further used to optimize the parameters of the pump laser and the optical Kerr medium. The beam smoothing effects of the joint use of continuous phase plate and polarization control plate with smoothing by spectral dispersion, as well as radial smoothing have been analyzed and compared in detail. Results indicate that, the delay time between each super-Gaussian pulse in the pump laser should be matched with the pulse width of each super-Gaussian pulse to achieve the best and stable radial smoothing effect, while the fluctuation of the peak intensity of each super-Gaussian pulse in the pump laser would degrade the radial smoothing effect. The selection of the optical Kerr medium directly determines its thickness and peak intensity of the pump laser to obtain the required wavefront modulation, which affects the feasibility of the radial smoothing scheme.

  15. Annealing a Follow-up Program: Improvement of the Dark Energy Figure of Merit for Optical Galaxy Cluster Surveys

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao-Yi; Rozo, Eduardo; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC /CCAPP, Columbus /KICP, Chicago /KIPAC, Menlo Park /SLAC

    2010-06-02

    The precision of cosmological parameters derived from galaxy cluster surveys is limited by uncertainty in relating observable signals to cluster mass. We demonstrate that a small mass-calibration follow-up program can significantly reduce this uncertainty and improve parameter constraints, particularly when the follow-up targets are judiciously chosen. To this end, we apply a simulated annealing algorithm to maximize the dark energy information at fixed observational cost, and find that optimal follow-up strategies can reduce the observational cost required to achieve a specified precision by up to an order of magnitude. Considering clusters selected from optical imaging in the Dark Energy Survey, we find that approximately 200 low-redshift X-ray clusters or massive Sunyaev-Zel'dovich clusters can improve the dark energy figure of merit by 50%, provided that the follow-up mass measurements involve no systematic error. In practice, the actual improvement depends on (1) the uncertainty in the systematic error in follow-up mass measurements, which needs to be controlled at the 5% level to avoid severe degradation of the results; and (2) the scatter in the optical richness-mass distribution, which needs to be made as tight as possible to improve the efficacy of follow-up observations.

  16. Hollow fiber optics with improved durability for high-peak-power pulses of Q-switched Nd:YAG lasers.

    Science.gov (United States)

    Matsuura, Yuji; Tsuchiuchi, Akio; Noguchi, Hiroshi; Miyagi, Mitsunobu

    2007-03-10

    To improve the damage threshold of hollow optical waveguides for transmitting Q-switched Nd:YAG laser pulses, we optimize the metallization processes for the inner coating of fibers. For silver-coated hollow fiber as the base, second, and third Nd:YAG lasers, drying silver films at a moderate temperature and with inert gas flow is found to be effective. By using this drying process, the resistance to high-peak-power optical pulse radiation is drastically improved for fibers fabricated with and without the sensitizing process. The maximum peak power transmitted in the fiber is greater than 20 MW. To improve the energy threshold of aluminum-coated hollow fibers for the fourth and fifth harmonics of Nd:YAG lasers, a thin silver film is added between the aluminum film and the glass substrate to increase adhesion of the aluminum coating. By using this primer layer, the power threshold improves to 3 MW for the fourth harmonics of a Q-switched Nd:YAG laser light.

  17. Performance improvement of hybrid subcarrier multiplexing optical spectrum code division multiplexing system using spectral direct decoding detection technique

    Science.gov (United States)

    Sahbudin, R. K. Z.; Abdullah, M. K.; Mokhtar, M.

    2009-06-01

    This paper proposes a hybrid subcarrier multiplexing/optical spectrum code division multiplexing (SCM/OSCDM) system for the purpose of combining the advantages of both techniques. Optical spectrum code division multiple-access (OSCDMA) is one of the multiplexing techniques that is becoming popular because of the flexibility in the allocation of channels, ability to operate asynchronously, enhanced privacy and increased capacity in bursty nature networks. On the other hand, subcarrier multiplexing (SCM) technique is able to enhance the channel data rate of OSCDMA systems. In this paper, a newly developed detection technique for the OSCDM called spectral direct decoding (SDD) detection technique is compared mathematically with the AND subtraction detection technique. The system utilizes a new unified code construction named KS (Khazani-Syed) code. The results characterizing the bit-error-rate (BER) show that SDD offers a significant improved performance at BER of 10 -9.

  18. Contrast improvement of continuous wave diffuse optical tomography reconstruction by hybrid approach using least square and genetic algorithm.

    Science.gov (United States)

    Patra, Rusha; Dutta, Pranab K

    2015-07-01

    Reconstruction of the absorption coefficient of tissue with good contrast is of key importance in functional diffuse optical imaging. A hybrid approach using model-based iterative image reconstruction and a genetic algorithm is proposed to enhance the contrast of the reconstructed image. The proposed method yields an observed contrast of 98.4%, mean square error of 0.638×10⁻³, and object centroid error of (0.001 to 0.22) mm. Experimental validation of the proposed method has also been provided with tissue-like phantoms which shows a significant improvement in image quality and thus establishes the potential of the method for functional diffuse optical tomography reconstruction with continuous wave setup. A case study of finger joint imaging is illustrated as well to show the prospect of the proposed method in clinical diagnosis. The method can also be applied to the concentration measurement of a region of interest in a turbid medium.

  19. Improvement of the dynamic range using background subtraction in single shot wide-field optical coherence tomography

    Science.gov (United States)

    Anna, Tulsi; Singh Mehta, Dalip; Sato, Manabu

    2015-12-01

    We investigated on the signal in single shot wide-field optical coherence tomographic (SS-WF-OCT) system to improve the dynamic range (DR). The SS-WF-OCT system is based on two-dimensional (2D) polarization Michelson interferometer and superluminescent diode (center wavelength of 842.5 nm) as light source. Two π-phase-shifted interferograms were acquired simultaneously using a single CCD camera and after subtraction, the en-face OCT image (area (x) 4.0 mm × (y) 4.3 mm) is obtained using 2D Hilbert transform. The OCT signal including incoherent background noises was analyzed. To improve the DR, background noise subtraction has been introduced and its measurement process is presented. This method is valuable during the background noise is stable. Using the scattering samples, such as, grind metal and polymer sponge with background subtraction algorithm, a significant reduction in background noise and improvement in the DR was demonstrated .

  20. Improvement of continuous-variable quantum key distribution systems by using optical preamplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Fossier, S; Debuisschert, T [Thales Research and Technology France, RD 128, 91767 Palaiseau Cedex (France); Diamanti, E; Tualle-Brouri, R; Grangier, P [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS, Univ. Paris-Sud, Campus Polytechnique, RD 128, 91127 Palaiseau Cedex (France)

    2009-06-14

    Continuous-variable quantum key distribution protocols have been implemented recently, based on Gaussian modulation of the quadratures of coherent states. A present limitation of such systems is the finite efficiency of the detectors, that can in principle be compensated for by the use of classical optical preamplifiers. Here we study this possibility in detail, by deriving the modified secret key generation rates when an optical parametric amplifier is placed at the output of the quantum channel. After presenting a general set of security proofs, we show that the use of preamplifiers does compensate all the imperfections of the detectors when the amplifier is optimal in terms of gain and noise. Imperfect amplifiers can also enhance the system performance, under conditions which are generally satisfied in practice.

  1. Tanshinone ⅡA protects rabbits against LPS-induced disseminated intravascular coagulation (DIC)

    Institute of Scientific and Technical Information of China (English)

    Liang-cai WU; Xi LIN; Hao SUN

    2012-01-01

    Aim:To evaluate the effects of tanshinone ⅡA (Tan ⅡA),a lipophilic diterpene from the Chinese herb Salvia miltiorrhiza,on lipopolysaccharide (LPS)-induced disseminated intravascular coagulation (DIC) in rabbits.Methods:LPS-induced DIC model was made in adult male New Zealand rabbits by continuous intravenous infusion of LPS (0.5 mg/kg)via marginal ear vein for 6 h.The animals were simultaneously administered with Tan ⅡA (1,3 and 10 mg/kg) or heparin (500 000IU/kg) through continuous infusion via the contralateral marginal ear vein for 6 h.Before and 2 and 6 h after the start of LPS infusion,blood samples were taken for biochemical analyses.Results:Continuous infusion of LPS into the rabbits gradually impaired the hemostatic parameters,damaged renal and liver functions,increased the plasma TNF-α level,and led to a high mortality rate (80%).Treatment of the rabbits with Tan ⅡA dose-dependently attenuated the increase in activated partial thromboplastin time (APTT),prothrombin time (PT) and fibrin-fibrinogen degradation products (FDP); ameliorated the decrease in plasma levels of fibrinogen and platelets; and reversed the decline in activity of protein C and antithrombin Ⅲ.Meanwhile,the treatment significantly suppressed the increase in the plasma levels of aminotransferase,creatinine and TNF-α,and led to much lower mortality (46.7% and 26.7% for the medium- and high-dose groups).Treatment of the rabbits with the high dose of heparin also effectively improved the hemostatic parameters,ameliorated liver and renal injuries,and reduced the plasma level of TNF-α,and significantly reduced the mortality (33.3%).Conclusion:Tan ⅡA exerts a protective effect against DIC in rabbits.

  2. Thromboelastometry (TEM) findings in disseminated intravascular coagulation in a pig model of endotoxinemia.

    Science.gov (United States)

    Schöchl, Herbert; Solomon, Cristina; Schulz, Arthur; Voelckel, Wolfgang; Hanke, Alexander; Van Griensven, Martijn; Redl, Heinz; Bahrami, Soheyl

    2011-01-01

    Standard coagulation tests have a low specificity and sensitivity for diagnosing disseminated intravascular coagulation. The aim of this study was to determine whether whole blood thromboelastometry (TEM) detects lipopolysaccharide (LPS)-induced changes in coagulation. Blood samples from 10 pigs were drawn at baseline, before and at the end of LPS infusion and 2, 3, 4 and 5 h after the start of endotoxinemia. Simultaneous to TEM, standard coagulation tests and extended coagulation analysis including tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1) were performed. Endotoxinemia resulted in a significant acceleration of the nonactivated TEM (NATEM) clotting time 2 h after the end of LPS infusion; in contrast, the changes in international normalized ratio and activated partial thromboplastin time suggested delayed initiation of coagulation. NATEM maximum clot firmness (MCF) and fibrin-based thromboelastometry test (FIBTEM)-MCF decreased significantly from baseline until the last time point (from 64.6 ± 7.8 and 35.1 ± 12.8 mm to 52.8 ± 4.6 and 21.4 ± 11.8 mm, respectively; P = 0.01 for both parameters). A sharp, transient increase of t-PA had no effect on maximum lysis in the NATEM test. PAI-1 increased significantly 3 h after the start of LPS infusion, paralleled by a decrease in maximum lysis. In conclusion, TEM was superior to standard coagulation tests in reflecting initial activation of coagulation during endotoxinemia. TEM further suggested consumption of coagulation substrate; at the same time, inhibition of plasminogen activation was accompanied by improved clot stability. Further investigations are necessary to establish the clinical relevance of these findings.

  3. Abnormal pulmonary artery stiffness in pulmonary arterial hypertension: in vivo study with intravascular ultrasound.

    Directory of Open Access Journals (Sweden)

    Edmund M T Lau

    Full Text Available BACKGROUND: There is increasing recognition that pulmonary artery stiffness is an important determinant of right ventricular (RV afterload in pulmonary arterial hypertension (PAH. We used intravascular ultrasound (IVUS to evaluate the mechanical properties of the elastic pulmonary arteries (PA in subjects with PAH, and assessed the effects of PAH-specific therapy on indices of arterial stiffness. METHOD: Using IVUS and simultaneous right heart catheterisation, 20 pulmonary segments in 8 PAH subjects and 12 pulmonary segments in 8 controls were studied to determine their compliance, distensibility, elastic modulus and stiffness index β. PAH subjects underwent repeat IVUS examinations after 6-months of bosentan therapy. RESULTS: AT BASELINE, PAH SUBJECTS DEMONSTRATED GREATER STIFFNESS IN ALL MEASURED INDICES COMPARED TO CONTROLS: compliance (1.50±0.11×10(-2 mm(2/mmHg vs 4.49±0.43×10(-2 mm(2/mmHg, p<0.0001, distensibility (0.32±0.03%/mmHg vs 1.18±0.13%/mmHg, p<0.0001, elastic modulus (720±64 mmHg vs 198±19 mmHg, p<0.0001, and stiffness index β (15.0±1.4 vs 11.0±0.7, p = 0.046. Strong inverse exponential associations existed between mean pulmonary artery pressure and compliance (r(2 = 0.82, p<0.0001, and also between mean PAP and distensibility (r(2 = 0.79, p = 0.002. Bosentan therapy, for 6-months, was not associated with any significant changes in all indices of PA stiffness. CONCLUSION: Increased stiffness occurs in the proximal elastic PA in patients with PAH and contributes to the pathogenesis RV failure. Bosentan therapy may not be effective at improving PA stiffness.

  4. Improved parameters metropolitan area network supported with all-optical network's technology

    Science.gov (United States)

    Gradkowska, Magdalena; Kalita, Mariusz

    2006-03-01

    The advantages of all-optical network's technics make them one of main elements of the metropolitan area networks. They enable different applications in high quality mulitimedia services and guarantee a constant and reliable access to the Internet. As the growing expansion of the Internet continues in an unpredictable direction, many new solutions are expected. The major challenge is the increasing demand for flexible, transparent and customised bandwidth services for both private and business customers.

  5. An efficient method to improve the proximity effect for electron beam optical disc mastering

    Science.gov (United States)

    Pan, C. T.; Chen, M. F.

    2005-04-01

    For the next-generation optical disc, electron beam mastering has been considered as a high-potential technique to fabricate a high-density optical disc. However, for electron beam mastering, the proximity effect caused by electron backscattering is an important problem. In this study, the influence of the proximity effect on the linewidth (full width at half magnitude, FWHM) and thickness of the residual resist is discussed. Some methods are presented to solve the proximity effect for optical disc mastering, i.e., by raising the electron beam voltage and depositing thin film material with low atomic number on a silicon substrate. In the study, thin film materials such as Al, Ni, SiO2, and Si3N4 are deposited on a silicon wafer to explore the proximity effect. The preliminary experimental results show that raising the electron beam voltage and depositing SiO2 or Si3N4 thin film on a silicon substrate can efficiently solve this problem. Later, the resist with a nano-pattern is transferred into a metal Ni-Co (nickel-cobalt) mould by electroplating. The technique of the Ni-Co electroplating process with hardness at least Vicker hardness (Hv) 650 and residual stress below 1.5 kg mm-2 is developed. Then, with the Ni-Co mould, a modified LIGA process is applied to produce a high-density optical disc. The Ni-Co mould serves as the master for the hot embossing process to replicate the nano-pattern onto the PMMA sheet. Since the feature size is down to the nanometre range, the study presents an innovative demoulding mechanism to demould the master from the PMMA sheet without damaging the nanometre patterns.

  6. A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy

    Science.gov (United States)

    Rajagopal, Vaishnavi; Stokes, Chris; Ferzoco, Alessandra

    2017-08-01

    We report a custom-geometry linear ion trap designed for fluorescence spectroscopy of gas-phase ions at ambient to cryogenic temperatures. Laser-induced fluorescence from trapped ions is collected from between the trapping rods, orthogonal to the excitation laser that runs along the axis of the linear ion trap. To increase optical access to the ion cloud, the diameter of the round trapping rods is 80% of the inscribed diameter, rather than the roughly 110% used to approximate purely quadrupolar electric fields. To encompass as much of the ion cloud as possible, the first collection optic has a 25.4 mm diameter and a numerical aperture of 0.6. The choice of geometry and collection optics yields 107 detected photons/s from trapped rhodamine 6G ions. The trap is coupled to a closed-cycle helium refrigerator, which in combination with two 50 Ohm heaters enables temperature control to below 25 K on the rod electrodes. The purpose of the instrument is to broaden the applicability of fluorescence spectroscopy of gas-phase ions to cases where photon emission is a minority relaxation pathway. Such studies are important to understand how the microenvironment of a chromophore influences excited state charge transfer processes. [Figure not available: see fulltext.

  7. Improved fixation quality provided by a Bessel beacon in an adaptive optics system.

    Science.gov (United States)

    Lambert, Andrew J; Daly, Elizabeth M; Dainty, Christopher J

    2013-07-01

    We investigate whether a structured probe beam that creates the beacon for use in a retinal imaging adaptive optics system can provide useful side effects. In particular we investigate whether a Bessel beam that is seen by the subject as a set of concentric rings has a dampening effect on fixation variations of the subject under observation. This calming effect would allow longer periods of observation, particularly for patients with abnormal fixation. An experimental adaptive optics system developed for retinal imaging is used to monitor the fluctuations in aberrations for artificial and human subjects. The probe beam is alternated between a traditional beacon and one provided by a Bessel beam created by SLM. Time-frequency analysis is used to indicate the differences in power and time variation during fixation depending on whether the Bessel beam or the traditional beacon is employed. Comparison is made with the response for an artificial eye to discount systemic variations. Significant evidence is accrued to indicate the reduced fluctuations in fixation when the Bessel beam is employed to create the beacon. © 2013 The Authors Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

  8. Effect of temperature and fixation on the optical properties of atherosclerotic tissue: a validation study of an ex-vivo whole heart cadaveric model

    NARCIS (Netherlands)

    Gnanadesigan, M.; Van Soest, G.; White, S.; Scoltock, S.; Ughi, G.J.; Baumbach, A.; Van der Steen, A.F.W.; Regar, E.; Johnson, T.W.

    2014-01-01

    Atherosclerotic plaque composition can be imaged using the optical attenuation coefficient derived from intravascular optical coherence tomography (OCT) data. The relation between optical properties and tissue type has been established on autopsy tissues. In this study, we validate an ex-vivo model

  9. Effect of temperature and fixation on the optical properties of atherosclerotic tissue: A validation study of an ex-vivo whole heart cadaveric model

    NARCIS (Netherlands)

    M. Gnanadesigan (Muthukaruppan); G. van Soest (Gijs); S. White (Stephen); S. Scoltock (Simon); G.J. Ughi (Giovanni); A. Baumbach (Andreas); A.F.W. van der Steen (Ton); E.S. Regar (Eveline); T.W. Johnson (Thomas)

    2014-01-01

    textabstractAtherosclerotic plaque composition can be imaged using the optical attenuation coefficient derived from intravascular optical coherence tomography (OCT) data. The relation between optical properties and tissue type has been established on autopsy tissues. In this study, we validate an ex

  10. Lung and renal uptake of techneticum Tc 99m sulphur colloid related to disseminated intravascular coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Jelle Teertstra, H.; Verdegaal, W.P.; Ras, G.J.

    1985-01-01

    In addition to a recently published case study, we present another three cases in which we observed both lung and renal uptake of technetium Tc 99m sulphur colloid which was related to a period of disseminated intravascular coagulation. Being familiar with this relationship may influence the diagnosis and course of the illness in certain patients.

  11. [Rhabdomyolysis, disseminated intravascular coagulation and multiple organ failure in a patient with cocaine and heroine poisoning].

    Science.gov (United States)

    Vreugdenhil, G; Ligthart, J; de Leeuw, P W

    1992-06-20

    A 19-year-old female patient with cocaine and heroin intoxication is described in whom several life threatening complications such as hypovolemic shock, cardiopulmonary insufficiency, rhabdomyolysis, diffuse intravascular coagulation and multiple organ failure occurred. The patient survived the intoxication after quick intensive treatment.

  12. Identification of atherosclerotic plaque components with intravascular ultrasound elastography in vivo: a Yucatan pig study.

    NARCIS (Netherlands)

    Korte, C.L. de; Sierevogel, M.J.; Mastik, F.; Strijder, C.; Schaar, J.A.; Velema, E.; Pasterkamp, G.; Serruys, P.W.; Steen, A.F.W. van der

    2002-01-01

    BACKGROUND: Intravascular ultrasound elastography assesses the local strain of the atherosclerotic vessel wall. In the present study, the potential to identify different plaque components in vivo was investigated. METHODS AND RESULTS: Atherosclerotic external iliac and femoral arteries (n=24) of 6 Y

  13. Introducing intravascular microdialysis for continuous lactate monitoring in patients undergoing cardiac surgery : a prospective observational study

    NARCIS (Netherlands)

    Schierenbeck, Fanny; Nijsten, Maarten W. N.; Franco-Cereceda, Anders; Liska, Jan

    2014-01-01

    Introduction: Lactate is a marker of hypoperfusion and may be used for risk assessment in critically ill patients. Although evidence suggests that repeated lactate measurements are of clinical interest, how and when lactate should be analyzed is controversial. Intravascular microdialysis provides a

  14. Serial intravascular ultrasound assessment of changes in coronary atherosclerotic plaque dimensions and composition: an update

    DEFF Research Database (Denmark)

    Hartmann, Marc; Huisman, Jennifer; Böse, Dirk;

    2011-01-01

    This manuscript reviews the use of serial intravascular ultrasound (IVUS) examination of coronary atherosclerosis in recent observational studies and randomized trials that revealed the effects of cholesterol-lowering and lipid-modifying therapies and offered novel insight into plaque progression...

  15. Introducing intravascular microdialysis for continuous lactate monitoring in patients undergoing cardiac surgery : a prospective observational study

    NARCIS (Netherlands)

    Schierenbeck, Fanny; Nijsten, Maarten W. N.; Franco-Cereceda, Anders; Liska, Jan

    2014-01-01

    Introduction: Lactate is a marker of hypoperfusion and may be used for risk assessment in critically ill patients. Although evidence suggests that repeated lactate measurements are of clinical interest, how and when lactate should be analyzed is controversial. Intravascular microdialysis provides a

  16. Congenital heart disease: cardiovascular MR imaging by using an intravascular blood pool contrast agent.

    NARCIS (Netherlands)

    Makowski, M.R.; Wiethoff, A.J.; Uribe, S.; Parish, V.; Botnar, R.M.; Bell, A.; Kiesewetter, C.; Beerbaum, P.B.J.; Jansen, C.H.; Razavi, R.; Schaeffter, T.; Greil, G.F.

    2011-01-01

    PURPOSE: To compare the image quality and diagnostic performance of a contrast agent-specific inversion-recovery (IR) steady-state free precession (SSFP) magnetic resonance (MR) imaging sequence performed by using an intravascular contrast agent (gadofosveset trisodium) with those of a commonly used

  17. Radiological imaging of florid intravascular papillary endothelial hyperplasia in the mandibule: case report and literature review.

    Science.gov (United States)

    Xu, Sheng-Sheng; Li, Dan

    2014-01-01

    Intravascular papillary endothelial hyperplasia was a rare benign vascular proliferative process as a result of papillary proliferation of the endothelial cells within the vessels. To our knowledge, we reported the second case occurring in the madibule, and the first reported in 1984 in the literature. We discussed manifestations of multislice computed tomography and panoramic radiography about the lesion and relevant literature was reviewed.

  18. Coronary plaque composition as assessed by greyscale intravascular ultrasound and radiofrequency spectral data analysis

    NARCIS (Netherlands)

    N. Gonzalo (Nieves); H.M. Garcia-Garcia (Hector); J.M.R. Ligthart (Jürgen); G.A. Rodriguez-Granillo (Gaston); E. Meliga (Emanuele); Y. Onuma (Yoshinobu); J.C.H. Schuurbiers (Johan); N. Bruining (Nico); P.W.J.C. Serruys (Patrick)

    2008-01-01

    textabstractObjectives: (i) To explore the relation between greyscale intravascular ultrasound (IVUS) plaque qualitative classification and IVUS radiofrequency data (RFD) analysis tissue types; (ii) to evaluate if plaque composition as assessed by RFD analysis can be predicted by visual assessment o

  19. Disseminated intravascular coagulation as an unusual presentation of an Epstein-Barr virus infection

    NARCIS (Netherlands)

    van Steijn, JHM; van Tol, KM; van Essen, LH; Gans, ROB

    2000-01-01

    Epstein-Barr viral (EBV)-infection usually presents as fever, sore throat, fatigue, lymphadenopathy and atypical lymphocytosis. We describe a patient with disseminated intravascular coagulation as the presenting symptom caused by a primary EBV infection. (C) 2000 Elsevier Science B.V. All rights res

  20. Determining Central Black Hole Masses in Distant Active Galaxies and Quasars. II. Improved Optical and UV Scaling Relationships

    DEFF Research Database (Denmark)

    Vestergaard, Marianne; Peterson, B. M.

    2006-01-01

    We present four improved empirical relationships useful for estimating the central black hole mass in nearby AGNs and distant luminous quasars alike using either optical or UV single-epoch spectroscopy. These mass-scaling relationships between line widths and luminosity are based on recently...... estimate that the absolute uncertainties in masses given by these mass-scaling relationships are typically around a factor of 4. We include in an Appendix mass estimates for all the Bright Quasar Survey (PG) quasars for which direct reverberation-based mass measurements are not available....

  1. High-resolution intravascular magnetic resonance quantification of atherosclerotic plaque at 3T

    Directory of Open Access Journals (Sweden)

    Qian Di

    2012-03-01

    Full Text Available Abstract Background The thickness of fibrous caps (FCT of atherosclerotic lesions is a critical factor affecting plaque vulnerability to rupture. This study tests whether 3 Tesla high-resolution intravascular cardiovascular magnetic resonance (CMR employing tiny loopless detectors can identify lesions and accurately measure FCT in human arterial specimens, and whether such an approach is feasible in vivo using animal models. Methods Receive-only 2.2 mm and 0.8 mm diameter intravascular loopless CMR detectors were fabricated for a clinical 3 Tesla MR scanner, and the absolute signal-to-noise ratio determined. The detectors were applied in a two-step protocol comprised of CMR angiography to identify atherosclerotic lesions, followed by high-resolution CMR to characterize FCT, lesion size, and/or vessel wall thickness. The protocol was applied in fresh human iliac and carotid artery specimens in a human-equivalent saline bath. Mean FCT measured by 80 μm intravascular CMR was compared with histology of the same sections. In vivo studies compared aortic wall thickness and plaque size in healthy and hyperlipidemic rabbit models, with post-mortem histology. Results Histology confirmed plaques in human specimens, with calcifications appearing as signal voids. Mean FCT agreed with histological measurements within 13% on average (correlation coefficient, R = 0.98; Bland-Altman analysis, -1.3 ± 68.9 μm. In vivo aortic wall and plaque size measured by 80 μm intravascular CMR agreed with histology. Conclusion Intravascular 3T CMR with loopless detectors can both locate atherosclerotic lesions, and accurately measure FCT at high-resolution in a strategy that appears feasible in vivo. The approach shows promise for quantifying vulnerable plaque for evaluating experimental therapies.

  2. Innovative instrumentation for detecting optical transients in the hypothesis of a new improved mirror at solar furnace of Almeria

    Energy Technology Data Exchange (ETDEWEB)

    Nanni, D.; Bartolini, C.; Cosentino, G.; Guarnieri, A.; Piccioni, A.; Beskin, G.; La Padula, C.

    2002-07-01

    The improvement of the solar Furnace mirror as light collector, with an expected Point Spread Function (PSF) of about less than 0.1 degree centigree, could provide a sufficient image definition for astronomical observations of Optical Transients (OTs). Wide-angle large aperture optics, combined with a finely pixelated imaging camera located in the focal plane 7.50 meters away from the mirrors, could offer a field of view (FOV) of 3 degree centigree diameter (30cm length). All these requirements involve the filling of focal plane by means of light having a spatial resolution of few millimeters and a time-resolution of the imager in the range of 50-1000 frame/s. A realistic approach, with regard to such demanding resolution, could be reached exploring properties of devices alternative to Photo-Multipliers tube (PMT) such as Multi Anode Photomultiplier tubes (MAPMT), semiconductor and hybrid devices (CCD, CMOS, HPD, Amorphous silicon detector etc.). These sensors, that during the last years have had a rapid development triggered by scientific, industrial and medical requirement, used or individually or coupled with optical field de magnifier (e. g. Tapers), present an efficient photon detection and a very high spatial resolution. (Author) 12 refs.

  3. Noise sources and improved performance of a mid-wave infrared uncooled silicon carbide optical photodetector.

    Science.gov (United States)

    Lim, Geunsik; Manzur, Tariq; Kar, Aravinda

    2014-12-20

    An uncooled photon detector is fabricated for the mid-wave infrared (MWIR) wavelength of 4.21 μm by doping an n-type 4H-SiC substrate with gallium using a laser doping technique. The dopant creates a p-type energy level of 0.3 eV, which is the energy of a photon corresponding to the MWIR wavelength 4.21 μm. This energy level was confirmed by optical absorption spectroscopy. The detection mechanism involves photoexcitation of carriers by the photons of this wavelength absorbed in the semiconductor. The resulting changes in the carrier densities at different energy levels modify the refractive index and, therefore, the reflectance of the semiconductor. This change in the reflectance constitutes the optical response of the detector, which can be probed remotely with a laser beam such as a He-Ne laser and the power of the reflected probe beam can be measured with a conventional laser power meter. The noise mechanisms in the probe laser, silicon carbide MWIR detector, and laser power meter affect the performance of the detector in regards to aspects such as the responsivity, noise equivalent temperature difference (NETD), and detectivity. For the MWIR wavelengths of 4.21 and 4.63 μm, the experimental detectivity of the optical photodetector of this study was found to be 1.07×10(10)  cm·Hz(1/2)/W, while the theoretical value was 1.11×10(10)  cm·Hz(1/2)/W. The values of NETD are 404 and 15.5 mK based on experimental data for an MWIR radiation source with a temperature of 25°C and theoretical calculations, respectively.

  4. Corrections and improvements of lung imaging under Optical Coherence Tomography (OCT)

    Science.gov (United States)

    Golabchi, Ali

    Visualization and correct assessment of alveolar volume via intact lung imaging is important to study and assess respiratory mechanics. Optical Coherence Tomography (OCT), a real time imaging technique based on near-infrared interferometry, can image several layers of distal alveoli in intact, ex-vivo lung tissue. However optical effects associated with heterogeneity of lung tissue, including the refraction caused by air-tissue interfaces along alveoli and duct walls, and changes in speed of light as it travels through the tissue, result in inaccurate measurement of alveolar volume. Experimentally such errors have been difficult to analyze because of lack of ''ground truth,'' as the lung has a unique microstructure of liquid-coated thin walls surrounding relatively large airspaces, which is difficult to model with synthetic foams. In addition, both lung and foams contain airspaces of highly irregular shape, further complicating quantitative measurement of optical artifacts and correction. To address this we have adapted the Bragg-Nye bubble raft, a crystalline two-dimensional arrangement of elements similar in geometry to alveoli (up to several hundred um in diameter with thin walls) as an inflated lung phantom in order to understand, analyze and correct these errors. By applying exact optical ray tracing on OCT images of the bubble raft, the errors are predicted and corrected. The results are validated by imaging the bubble raft with OCT from one edge and with a charged coupled device (CCD) camera in transillumination from top, providing ground truth for the OCT. We also developed a tomographic technique based on incoherent summation of multiple angle-diverse images by utilizing image registration to increase our depth of imaging and our results were validated by utilizing the inflated lung phantom. In this thesis also, an experimental apparatus for macro-scale mechanical probing of lung with in-situ micro-scale imaging of alveolar deformation was analyzed

  5. Identification of small molecules that improve ATP synthesis defects conferred by Leber's hereditary optic neuropathy mutations.

    Science.gov (United States)

    Datta, Sandipan; Tomilov, Alexey; Cortopassi, Gino

    2016-09-01

    Inherited mitochondrial complex I mutations cause blinding Leber's hereditary optic neuropathy (LHON), for which no curative therapy exists. A specific biochemical consequence of LHON mutations in the presence of trace rotenone was observed: deficient complex I-dependent ATP synthesis (CIDAS) and mitochondrial O2 consumption, proportional to the clinical severity of the three primary LHON mutations. We optimized a high-throughput assay of CIDAS to screen 1600 drugs to 2, papaverine and zolpidem, which protected CIDAS in LHON cells concentration-dependently. TSPO and cAMP were investigated as protective mechanisms, but a conclusive mechanism remains to be elucidated; next steps include testing in animal models.

  6. Treatment of Disseminated Intravascular Coagulation%浅谈弥散性血管内凝血的治疗体会

    Institute of Scientific and Technical Information of China (English)

    贾金凤

    2015-01-01

    Objective Disseminated intravascular coagulation therapy were discussed. Methods to select patients diagnosed with this disease in our hospital between January 2012 to December 2014 were treated 20 cases of research and analysis. Results 20 patients were discharged 12 patients , 6 patients had some improvement , 2 cases of therapy, treatment improvement rate of 90%. Conclusion For patients with disseminated intravascular hemorrhage take early detection and early diagnosis and anticoagulant treatment can get the desired therapeutic effect .%目的:对弥散性血管内凝血的治疗进行探讨。方法随去选取我院2012年1月~2014年12月间收治的本病确诊患者20例进行研究分析。结果20例患者中有12例痊愈出院,有6例有一定好转,2例治疗无效,治疗好转率为90%。结论对于弥散性血管内出血患者采取早发现早确诊,并进行抗凝治疗可以得到理想的治疗效果。

  7. Improvement of Response Performance of Liquid Crystal Optical Devices by using a Low Viscosity Component

    Institute of Scientific and Technical Information of China (English)

    PENG Zeng-Hui; LIU Yong-Gang; YAO Li-Shuang; CAO Zhao-Liang; MU Quan-Quan; HU Li-Fa; LU Xing-Hai; XUAN Li; ZHANG Zhi-Yong

    2011-01-01

    Difluorooxymethylene-bridged (CF2O) liquid crystal (LC) with low viscosity is prepared and used as a fast response LC material. When the material is mixed with isothiocyanato LCs with high birefringence, the visco-elastic coefficient of the mixture decreases evidently and, accordingly, the response performance increases. While the concentration of CF2O LCs is about 7%, the LC mixture approximately maintains high birefringence and exhibits a fastest response performance that is 14% higher than that of pure isothiocyanato LCs. Therefore, the LC material and mixing method could find useful applications in optical devices.%@@ Difluorooxymethylene-bridged(CF2O)liquid crystal(LC)with low viscosity is prepared and used as a fast response LC material.When the material is mixed with isothiocyanato LCs with high birefringence,the visco-elastic coefficient of the mixture decreases evidently and,accordingly,the response performance increases.While the concentration of CF2O LCs is about 7%,the LC mixture approximately maintains high birefringence and exhibits a fastest response performance that is 14%higher than that of pure isothiocyanato LCs.Therefore,the LC material and mixing method could find useful applications in optical devices.

  8. Improving Continuous-Variable Measurement-Device-Independent Multipartite Quantum Communication with Optical Amplifiers*

    Science.gov (United States)

    Guo, Ying; Zhao, Wei; Li, Fei; Huang, Duan; Liao, Qin; Xie, Cai-Lang

    2017-08-01

    The developing tendency of continuous-variable (CV) measurement-device-independent (MDI) quantum cryptography is to cope with the practical issue of implementing scalable quantum networks. Up to now, most theoretical and experimental researches on CV-MDI QKD are focused on two-party protocols. However, we suggest a CV-MDI multipartite quantum secret sharing (QSS) protocol use the EPR states coupled with optical amplifiers. More remarkable, QSS is the real application in multipartite CV-MDI QKD, in other words, is the concrete implementation method of multipartite CV-MDI QKD. It can implement a practical quantum network scheme, under which the legal participants create the secret correlations by using EPR states connecting to an untrusted relay via insecure links and applying the multi-entangled Greenberger-Horne-Zeilinger (GHZ) state analysis at relay station. Even if there is a possibility that the relay may be completely tampered, the legal participants are still able to extract a secret key from network communication. The numerical simulation indicates that the quantum network communication can be achieved in an asymmetric scenario, fulfilling the demands of a practical quantum network. Additionally, we illustrate that the use of optical amplifiers can compensate the partial inherent imperfections of detectors and increase the transmission distance of the CV-MDI quantum system.

  9. Improved fluoroimmunoassays using the dye Alexa Fluor 647 with the RAPTOR, a fiber optic biosensor.

    Science.gov (United States)

    Anderson, George P; Nerurkar, Nandan L

    2002-12-20

    The performance of the fluorescent dye Alexa Fluor 647 (AF647) was explored as an alternative to Cy5 for immunoassays on the RAPTOR, a fiber optic biosensor. The RAPTOR performs sandwich fluoroimmunoassays on the surface of small polystyrene optical waveguides for analyte detection. Fluorescence and immunoassay data were examined at various dye-to-protein (D/P) ratios for both Cy5 and Alexa Fluor 647. Primarily, due to the self-quenching characteristics of Cy5, Alexa Fluor 647 is substantially more effective in fluoroimmunoassays, yielding over twice the signal for any given analyte concentration. Alexa Fluor 647 can be attached to antibodies at higher ratios, D/P=6, before self-quenching begins to limit the dye's effectiveness. Furthermore, while Alexa Fluor 647 becomes quenched at high dye-to-protein ratios, D/P=9, the net fluorescence yield reaches a maximum, as opposed to Cy5-labeled proteins, which become nearly nonfluorescent at high labeling ratios, D/P> or =6. The limitations of Cy5 were elucidated with an immunoassay for ricin, while the advantages of Alexa Fluor 647 were demonstrated in both direct binding assays as well as in a sandwich immunoassay for staphylococcal enterotoxin B.

  10. An improved distributed routing algorithm for Benes based optical NoC

    CERN Document Server

    Zhang, Jing; Yang, Yintang

    2011-01-01

    Integrated optical interconnect is believed to be one of the main technologies to replace electrical wires. Optical Network-on-Chip (ONoC) has attracted more attentions nowadays. Benes topology is a good choice for ONoC for its rearrangeable non-blocking character, multistage feature and easy scalability. Routing algorithm plays an important role in determining the performance of ONoC. But traditional routing algorithms for Benes network are not suitable for ONoC communication, we developed a new distributed routing algorithm for Benes ONoC in this paper. Our algorithm selected the routing path dynamically according to network condition and enables more path choices for the message traveling in the network. We used OPNET to evaluate the performance of our routing algorithm and also compared it with a well-known bit-controlled routing algorithm. ETE delay and throughput were showed under different packet length and network sizes. Simulation results show that our routing algorithm can provide better performance...

  11. Improving the visualization of electron-microscopy data through optical flow interpolation

    KAUST Repository

    Carata, Lucian

    2013-01-01

    Technical developments in neurobiology have reached a point where the acquisition of high resolution images representing individual neurons and synapses becomes possible. For this, the brain tissue samples are sliced using a diamond knife and imaged with electron-microscopy (EM). However, the technique achieves a low resolution in the cutting direction, due to limitations of the mechanical process, making a direct visualization of a dataset difficult. We aim to increase the depth resolution of the volume by adding new image slices interpolated from the existing ones, without requiring modifications to the EM image-capturing method. As classical interpolation methods do not provide satisfactory results on this type of data, the current paper proposes a re-framing of the problem in terms of motion volumes, considering the depth axis as a temporal axis. An optical flow method is adapted to estimate the motion vectors of pixels in the EM images, and this information is used to compute and insert multiple new images at certain depths in the volume. We evaluate the visualization results in comparison with interpolation methods currently used on EM data, transforming the highly anisotropic original dataset into a dataset with a larger depth resolution. The interpolation based on optical flow better reveals neurite structures with realistic undistorted shapes, and helps to easier map neuronal connections. © 2011 ACM.

  12. Improving OPTICS Algorithm with Imperialist Competitive Algorithm: Choosing Automatically Best Parameters

    Directory of Open Access Journals (Sweden)

    Mahdi Ghorbani

    2016-05-01

    Full Text Available Clustering based on similarity is one of the most important stages in data analysis and a beneficial tool for data mining. There are a wide range of data from which a clear pattern cannot be driven using common clustering methods, data with unusual shapes. Scientists introduced density-based clustering algorithms to resolve this issue and enable clustering for this kind of data.Among all density-based clustering algorithms, Ordering points to identify the clustering structure (OPTICS is an algorithm for finding density-based clusters in spatial data. Density-based methods describe clusters as dense areas among diffused ones. An informal definition of cluster is: “For each intra-cluster point, neighborhood with specific radius Ɛ, must contains minimum number of point’s µ.” It’s very difficult to specify these two parameters for any types of data and needs great effort setting up them to achieve desired results.The main goal of this research is to use meta-heuristic methods especially Imperialist Competitive Algorithm (ICA to precise estimation of these parameters (Ɛ, µ so that we can apply them to OPTICS Algorithm to achieve accurate and high quality clusters for any data sets. In order to evaluation of mentioned method, we utilized data sets specialized for classification and removed class label. Comparing our results with original one, proved that our method is produced a precise class label.

  13. Lensless multiple-image optical encryption based on improved phase retrieval algorithm.

    Science.gov (United States)

    Huang, Jian-Ji; Hwang, Hone-Ene; Chen, Chun-Yuan; Chen, Ching-Mu

    2012-05-01

    A novel architecture of the optical multiple-image encryption based on the modified Gerchberg-Saxton algorithm (MGSA) by using cascading phase only functions (POFs) in the Fresnel transform (FrT) domain is presented. This proposed method can greatly increase the capacity of the system by avoiding the crosstalk, completely, between the encrypted target images. Each present stage encrypted target image is encoded as to a complex function by using the MGSA with constraining the encrypted target image of the previous stage. Not only the wavelength and position parameters in the FrT domain can be keys to increase system security, the created POFs are also served mutually as the encryption keys to decrypt target image from present stage into next stage in the cascaded scheme. Compared with a prior method [Appl. Opt.48, 2686-2692 (2009)], the main advantages of this proposed encryption system is that it does not need any transformative lenses and this makes it very efficient and easy to implement optically. Simulation results show that this proposed encryption system can successfully achieve the multiple-image encryption via fewer POFs, which is more advantageous in simpler implementation and efficiency than a prior method where each decryption stage requires two POFs to accomplish this task.

  14. Biomedical optics centers: forty years of multidisciplinary clinical translation for improving human health

    Science.gov (United States)

    Tromberg, Bruce J.; Anderson, R. Rox; Birngruber, Reginald; Brinkmann, Ralf; Berns, Michael W.; Parrish, John A.; Apiou-Sbirlea, Gabriela

    2016-12-01

    Despite widespread government and public interest, there are significant barriers to translating basic science discoveries into clinical practice. Biophotonics and biomedical optics technologies can be used to overcome many of these hurdles, due, in part, to offering new portable, bedside, and accessible devices. The current JBO special issue highlights promising activities and examples of translational biophotonics from leading laboratories around the world. We identify common essential features of successful clinical translation by examining the origins and activities of three major international academic affiliated centers with beginnings traceable to the mid-late 1970s: The Wellman Center for Photomedicine (Mass General Hospital, USA), the Beckman Laser Institute and Medical Clinic (University of California, Irvine, USA), and the Medical Laser Center Lübeck at the University of Lübeck, Germany. Major factors driving the success of these programs include visionary founders and leadership, multidisciplinary research and training activities in light-based therapies and diagnostics, diverse funding portfolios, and a thriving entrepreneurial culture that tolerates risk. We provide a brief review of how these three programs emerged and highlight critical phases and lessons learned. Based on these observations, we identify pathways for encouraging the growth and formation of similar programs in order to more rapidly and effectively expand the impact of biophotonics and biomedical optics on human health.

  15. Clinical analysis of 28 cases with obstetric disseminated intravascular coagulation%产科弥漫性血管内凝血28例临床分析

    Institute of Scientific and Technical Information of China (English)

    侯桂玉; 郭跃文

    2014-01-01

    Objective To explore the cause, treatment programs and prognostic factors of obstetric disseminated intravascular coagulation. Methods 28 pregnant women with disseminated intravascular coagulation in our hospital from January 2006 to January 2014 were selected, the cause and clinical manifestations of the pregnant women with disseminated intravascular coagulation were retrospectively analyzed. Results 28 pregnant women were all rescued successfully, no maternal deaths;3 cases had total hysterectomy, 1 case had subtotal hysterectomy, 6 cases had uterine arterial embolization. Fetal condition, 27 neonatal survived, 1 case was intrauterine death, 4 cases were stillbirth, neonatal mortality rate was 15.62%. Patients' coagulation function had significant differences before and after the treatment of disseminated intravascular coagulation. After the treatment, patients' coagulation function had been significantly improved. Conclusion In the treatment of disseminated intravascular coagulation, it is main to remove the cause of disseminated intravascular coagulation, while to give effective hemostasis, add volume and other related symptomatic treatment. It plays a very important role for reservations uterus of uterine arterial embolization and plus line B-Lynch suture uterus when Laparotomy again.%目的:探讨产科弥漫性血管内凝血的发生原因、治疗方案及其预后的影响因素。方法选择2006年1月~2014年1月在我院妇产科收治的28例发生弥漫性血管内凝血的孕妇作为本次临床观察的研究对象,回顾性分析孕妇发生弥漫性血管内凝血的原因及其临床表现,探讨弥漫性血管内凝血的临床治疗效果。结果28例孕妇均抢救成功,无产妇死亡病例;子宫全切除的患者有3例,次全子宫切除患者1例,子宫动脉灌注栓塞术患者6例。胎儿情况,新生儿存活27例,宫内死亡1例,死胎4例,新生儿死亡率为15.62%。患者在弥漫性血管内凝血

  16. Si Hybrid Solar Cells with 13% Efficiency via Concurrent Improvement in Optical and Electrical Properties by Employing Graphene Quantum Dots

    KAUST Repository

    Tsai, Meng Lin

    2015-12-18

    By employing graphene quantum dots (GQDs) in PEDOT:PSS, we have achieved an efficiency of 13.22% in Si/PEDOT:PSS hybrid solar cells. The efficiency enhancement is based on concurrent improvement in optical and electrical properties by the photon downconversion process and the improved conductivity of PEDOT:PSS via appropriate incorporation of GQDs. After introducing GQDs into PEDOT:PSS, the short circuit current and the fill factor of rear-contact optimized hybrid cells are increased from 32.11 to 36.26 mA/cm and 62.85% to 63.87%, respectively. The organic-inorganic hybrid solar cell obtained herein holds the promise for developing photon-managing, low-cost, and highly efficient photovoltaic devices.

  17. Improvement of dispersion stability and optical properties of CdSe/ZnSe structured quantum dots by polymer coating.

    Science.gov (United States)

    Kwon, Young-Tae; Eom, Nu Si A; Choi, Yo-Min; Kim, Bum-Sung; Kim, Taek-Soo; Lee, Chan-Gi; Lee, Kun-Jae; Choa, Yong-Ho

    2014-10-01

    In this study, CdSe core and CdSe/ZnSe core/shell quantum dots with a narrow size distribution were synthesized in a micro-reactor. A PMMA coating applied to the surface of CdSe/ZnSe core/shell QDs to prevent degradation gave improved dispersion stability compared to the CdSe core and CdSe/ZnSe core/shell. Many previous approaches to dispersion stability have not been quantitatively assessed. The dispersion stability was confirmed by multiple light scattering measurement. Additionally, the PMMA-coated CdSe/ZnSe QDs showed greatly improved optical properties with a photoluminescence quantum yield up to 80%. This structural motif is expected to prevent the degradation of QDs.

  18. Image quality improvement by the structured light illumination method in an optical readout cantilever array infrared imaging system.

    Science.gov (United States)

    Feng, Yun; Zhao, Yuejin; Liu, Ming; Dong, Liquan; Yu, Xiaomei; Kong, Lingqin; Ma, Wei; Liu, Xiaohua

    2015-04-01

    The structured light illumination method is applied in an optical readout uncooled infrared imaging system to improve the IR image quality. The unavoidable nonuniform distribution of the initial bending angles of the bimaterial cantilever pixels in the focal plane array (FPA) can be well compensated by this method. An ordinary projector is used to generate structured lights of different intensity distribution. The projected light is divided into patches of rectangular regions, and the brightness of each region can be set automatically according to the deflection angles of the FPA and the light intensity focused on the imaging plane. By this method, the FPA image on the CCD plane can be much more uniform and the image quality of the IR target improved significantly. A comparative experiment is designed to verify the effectiveness. The theoretical analysis and experimental results show that the proposed structured light illumination method outperforms the conventional one, especially when it is difficult to perfect the FPA fabrication.

  19. Improved structure stability, optical and magnetic properties of Ca and Ti co-substituted BiFeO3 nanoparticles

    Science.gov (United States)

    Kumar, Vijay; Singh, Satyendra

    2016-11-01

    We report the optical and magnetic properties of single-crystalline Ca and Ti co-substituted bismuth ferrite, Bi1-xCaxFe1-xTixO3, nanoparticles, synthesized by a facile sol-gel methodology in the compositional range wherein 0 ≤ x ≤ 0.25. X-ray diffraction (XRD) and transmission electron microscopy (TEM) investigations show that all samples possess a rhombohedrally distorted perovskite structure with space group R3c. Ca and Ti co-substitution controls the formation of secondary phases and improved the stability of perovskite phase of BiFeO3. The average particle size was estimated by Williamson Hall plot, confirmed by TEM, and found to be about 59, 50, 46, 41, 40 and 38 nm of Bi1-xCaxFe1-xTixO3 for x = 0, 0.05, 0.10, 0.15, 0.20 and 0.25, respectively. The UV-vis absorption study reveal the strong absorption of visible light with a small optical band gap (1.77-2.25 eV) for 0 ≤ x ≤ 0.25 indicates a possibility of utilizing for photocatalytic activities. The magnetic study at room-temperature displays the improved magnetization and coercive field in Bi1-xCaxFe1-xTixO3 nanoparticles due to the release of the latent magnetization locked within the toroidal spin structure of BiFeO3.

  20. Integration and fusion of standard automated perimetry and optical coherence tomography data for improved automated glaucoma diagnostics

    Directory of Open Access Journals (Sweden)

    Bizios Dimitrios

    2011-08-01

    Full Text Available Abstract Background The performance of glaucoma diagnostic systems could be conceivably improved by the integration of functional and structural test measurements that provide relevant and complementary information for reaching a diagnosis. The purpose of this study was to investigate the performance of data fusion methods and techniques for simple combination of Standard Automated Perimetry (SAP and Optical Coherence Tomography (OCT data for the diagnosis of glaucoma using Artificial Neural Networks (ANNs. Methods Humphrey 24-2 SITA standard SAP and StratusOCT tests were prospectively collected from a randomly selected population of 125 healthy persons and 135 patients with glaucomatous optic nerve heads and used as input for the ANNs. We tested commercially available standard parameters as well as novel ones (fused OCT and SAP data that exploit the spatial relationship between visual field areas and sectors of the OCT peripapillary scan circle. We evaluated the performance of these SAP and OCT derived parameters both separately and in combination. Results The diagnostic accuracy from a combination of fused SAP and OCT data (95.39% was higher than that of the best conventional parameters of either instrument, i.e. SAP Glaucoma Hemifield Test (p Conclusions Compared to the use of SAP parameters, input from the combination of fused OCT and SAP parameters, and from fused OCT data, significantly increased the performance of ANNs. Integrating parameters by including a priori relevant information through data fusion may improve ANN classification accuracy compared to currently available methods.

  1. Ar plasma irradiation improved optical and electrical properties of TiO₂/Ag/TiO₂ multilayer thin film.

    Science.gov (United States)

    Fang, Yingcui; He, Jinjun; Zhang, Kang; Xiao, Chuanyun; Zhang, Bing; Shen, Jie; Niu, Haihong; Yan, Rong; Chen, Junling

    2015-12-01

    Embedding a thin metal layer between two thin dielectric or semiconductor layers [dielectric/metal/dielectric (DMD)] leads to a kind of transparent electrode that is promising as a substitute for the currently widely applied indium tin oxide electrode. However, the optical and electrical properties of DMD still wait for further improvement. In this study, Ar plasma irradiation (API) was, for the first time to our knowledge, applied to improve the optical and electrical properties of a TiO2/Ag/TiO2 electrode that was fabricated by electron-beam evaporation of TiO2 and electric-resistance heating of high purity Ag under vacuum. Ar plasma was produced by radio frequency glow discharge. The Ag layer was bombarded before the second layer of TiO2 was deposited. The electrode with configuration of TiO2 (24  nm)/Ag(14  nm)/TiO2 (24  nm) after API for 10 s shows excellent performance. The mean transmittance between 370 and 800 nm reaches 94% and the sheet resistance is as low as 6  Ω/sq, while Haacke's figure of merit is as high as 112×10(-3)  Ω(-1). The improvement mechanism is discussed based on field emission scanning electron microscope images and absorption spectra. The improvement is attributed to the fact that API reduces the localized surface plasmon resonance of Ag nanoparticles and makes the Ag film thinner and denser.

  2. Improved Energy Efficiency for Optical Transport Networks by Elastic Forward Error Correction

    DEFF Research Database (Denmark)

    Rasmussen, Anders; Yankov, Metodi Plamenov; Berger, Michael Stübert

    2014-01-01

    is available. We show that this additional parity information decreases the number of necessary decoding iterations and thus reduces the power consumption in iterative decoders during periods of low load. The code rate adjustments can be done on a frame-by-frame basis and thus make it possible to manipulate...... the balance between effective data rate and FEC coding gain without any disruption to the live traffic. As a consequence, these automatic adjustments can be performed very often based on the current traffic demand and bit error rate performance of the links through the network. The FEC scheme itself...... is designed to work as a transparent add-on to transceivers running the optical transport network (OTN) protocol, adding an extra layer of elastic soft-decision FEC to the built-in hard-decision FEC implemented in OTN, while retaining interoperability with existing OTN equipment. In order to facilitate...

  3. Performance improvement of an optical network providing services based on multicast

    CERN Document Server

    Reinhard, Vincent; Tomasik, Joanna; Barth, Dominique; Weisser, Marc-Antoine

    2011-01-01

    Operators of networks covering large areas are confronted with demands from some of their customers who are virtual service providers. These providers may call for the connectivity service which fulfils the specificity of their services, for instance a multicast transition with allocated bandwidth. On the other hand, network operators want to make profit by trading the connectivity service of requested quality to their customers and to limit their infrastructure investments (or do not invest anything at all). We focus on circuit switching optical networks and work on repetitive multicast demands whose source and destinations are {\\em \\`a priori} known by an operator. He may therefore have corresponding trees "ready to be allocated" and adapt his network infrastructure according to these recurrent transmissions. This adjustment consists in setting available branching routers in the selected nodes of a predefined tree. The branching nodes are opto-electronic nodes which are able to duplicate data and retransmit...

  4. Plasmon resonance gold nanoparticles for improving optical diagnostics and photothermal therapy of tumor

    Science.gov (United States)

    Zagainova, E. V.; Sirotkina, M. A.; Shirmanova, M. V.; Elagin, V. V.; Kirillin, M.; Agrba, P.; Kamensky, V. A.; Nadtochenko, V. A.

    2010-02-01

    The study was performed on 16 CBA-line female mice with transplanted cervical cancer. 0.2 ml of gold nanoparticle solution with a concentration of 109 particles/ml were injected into the animals intravenously. The particles were 200-250 nm in size; the plasmon-resonance related extinction maximum was at the wavelength of 850-950 nm. Accumulation of the nanoparticles into tumor node was visualized by the method of optical coherence tomography (OCT). When the accumulation of nanoparticles in the tumor was maximal, hyperthermia was accomplished using the LSP-AZOR laser setup generating cw radiation at 810 nm. The duration of exposition was 20 min. The therapeutical effect was assessed by the rate of tumor growth inhibition (TGI, %). Determining the instant when nanoparticle concentration in tumor tissue reaches its maximum enables more efficient laser impact. The use of nanoparticles decreases laser irradiation power and ensures local action.

  5. 3D automatic quantification applied to optically sectioned images to improve microscopy analysis

    Directory of Open Access Journals (Sweden)

    JE Diaz-Zamboni

    2009-08-01

    Full Text Available New fluorescence microscopy techniques, such as confocal or digital deconvolution microscopy, allow to easily obtain three-dimensional (3D information from specimens. However, there are few 3D quantification tools that allow extracting information of these volumes. Therefore, the amount of information acquired by these techniques is difficult to manipulate and analyze manually. The present study describes a model-based method, which for the first time shows 3D visualization and quantification of fluorescent apoptotic body signals, from optical serial sections of porcine hepatocyte spheroids correlating them to their morphological structures. The method consists on an algorithm that counts apoptotic bodies in a spheroid structure and extracts information from them, such as their centroids in cartesian and radial coordinates, relative to the spheroid centre, and their integrated intensity. 3D visualization of the extracted information, allowed us to quantify the distribution of apoptotic bodies in three different zones of the spheroid.

  6. Using wavelength-normalized optical spectroscopy to improve the accuracy of bacteria growth rate quantification

    Science.gov (United States)

    McBirney, Samantha E.; Trinh, Kristy; Wong-Beringer, Annie; Armani, Andrea M.

    2017-02-01

    One of the fundamental analytical measurements performed in microbiology is monitoring and characterizing cell concentration in culture media. Measurement error will give rise to reproducibility problems in a wide range of applications, from biomanufacturing to basic research. Therefore, it is critical that the generated results are consistent. Single wavelength optical density (OD) measurements have become the preferred approach. Here, we compare the conventional OD600 technique with a multi-wavelength normalized scattering optical spectroscopy method to measure the growth rates of Pseudomonas aeruginosa and Staphylococcus aureus, two of the leading nosocomial pathogens with proven abilities to develop resistance. The multi-wavelength normalization process minimizes the impact of bacteria byproducts and environmental noise on the signal, thereby accurately quantifying growth rates with high fidelity at low concentrations. In contrast, due to poor absorbance and scattering at 600 nm, the classic OD600 measurement method is able to detect bacteria but cannot quantify the growth rate reliably. Our wavelength-normalization protocol to detect bacteria growth rates can be readily and easily adopted by research labs, given that it only requires the use of a standard spectrophotometer and implementation of straightforward data analysis. Measuring and monitoring bacteria growth rates play a critical role in a wide range of settings, spanning from therapeutic design and development to diagnostics and disease prevention. Having a full understanding of the growth cycles of bacteria known to cause severe infections and diseases will lead to a better understanding of the pathogenesis of these illnesses, leading to better treatment and, ultimately, the development of a cure.

  7. Improved laser damage threshold performance of calcium fluoride optical surfaces via Accelerated Neutral Atom Beam (ANAB) processing

    Science.gov (United States)

    Kirkpatrick, S.; Walsh, M.; Svrluga, R.; Thomas, M.

    2015-11-01

    Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface

  8. The effect of vascular curvature on three-dimensional reconstruction of intravascular ultrasound images.

    Science.gov (United States)

    Wiet, S P; Vonesh, M J; Waligora, M J; Kane, B J; McPherson, D D

    1996-01-01

    To characterize the effect of vessel curvature on the geometric accuracy of conventional three-dimensional reconstruction (3DR) algorithms for intravascular ultrasound image data. A common method of 3DR for intravascular ultrasound image data involves geometric reassembly and volumetric interpolation of a spatially related sequence of tomographic cross sections generated by an ultrasound catheter withdrawn at a constant rate through a vascular segment of interest. The resulting 3DR is displayed as a straight segment, with inherent vascular curvature neglected. Most vascular structures, however, are not straight but curved to some degree. For this reason, vascular curvature may influence the accuracy of computer-generated 3DR. We collected image data using three different intravascular ultrasound catheters (2.9 Fr, 4.3 Fr, 8.0 Fr) during a constant-rate pullback of 1 mm/sec through tubing of known diameter with imposed radii of curvature ranging from 2 to 10 cm. Image data were also collected from straight tubing. Image data were digitized at 1.0-mm intervals through a length of 25 mm. Two passes through each radius of curvature were performed with each intravascular ultrasound catheter. 3DR lumen volume for each radius of curvature was compared to that theoretically expected from a straight cylindrical segment. Differences between 3DR lumen volume of theoretical versus curved (actual) tubes were quantified as absolute percentage error and categorized as a function of curvature. Tubing deformation error was quantified by quantitative coronary angiography (QCA). Volumetric errors ranged from 1% to 35%, with an inverse relationship demonstrated between 3DR lumen volume and segmental radius of curvature. Higher curvatures (r curvatures (r > 6.0 cm). This trend was exhibited for all three catheters and was shown to be independent of tubing deformation artifacts. QCA-determined percentage diameter stenosis indicated no deformation error as a function of curvature. Total

  9. COAGULACIÓN INTRAVASCULAR DISEMINADA SECUNDARIA A ANEURISMA AÓRTICO DIAGNOSTICADA TRAS EXTRACCIÓN DENTAL

    Directory of Open Access Journals (Sweden)

    Cuevas-Ruiz MV

    2006-04-01

    Full Text Available RESUMEN:Las manifestaciones de la coagulación intravascular diseminada (CID están determinadas por la causa subyacente; sin embargo, en los casos de CID compensada el diagnóstico se basa en las pruebas de laboratorio.Presentamos el caso de un varón de 81 años al que se diagnostico de una coagulación intravascular diseminada secundaria a un aneurisma gigante de ambas ilíacas tras una extracción dentaria. SUMMARYThe clinical presentation of disseminated intravascular coagulopathy (DIC is determined by the underlying disease. However, in patients with chronic DIC the diagnostic is based in laboratory tests.We report a case of an 81-year-old male who was diagnosed disseminated intravascular coagulopathy secondary to gigant iliac aneurysm after a dental extraction

  10. Accurate monitoring of intravascular fluid volume: A novel application of intrathoracic impedance measures for the guidance of volume reduction therapy

    Directory of Open Access Journals (Sweden)

    Barbara A. Lara

    2015-09-01

    Conclusion: Impedance vectors derived from a multivector monitoring system reflect changes in intravascular plasma volume. Two of these vectors most closely track changes in plasma volume and may be used to more accurately guide and optimize volume reduction therapy.

  11. Optical signal to noise ratio improvement through unbalanced noise beating in phase-sensitive parametric amplifiers.

    Science.gov (United States)

    Malik, R; Kumpera, A; Olsson, S L I; Andrekson, P A; Karlsson, M

    2014-05-05

    We investigate the beating of signal and idler waves, which have imbalanced signal to noise ratios, in a phase-sensitive parametric amplifier. Imbalanced signal to noise ratios are achieved in two ways; first by imbalanced noise loading; second by varying idler to signal input power ratio. In the case of imbalanced noise loading the phase-sensitive amplifier improved the signal to noise ratio from 3 to 6 dB, and in the case of varying idler to signal input power ratio, the signal to noise ratio improved from 3 to in excess of 20 dB.

  12. Aerosol decadal trends – Part 1: In-situ optical measurements at GAW and IMPROVE stations

    Directory of Open Access Journals (Sweden)

    M. Collaud Coen

    2013-01-01

    Full Text Available Currently many ground-based atmospheric stations include in-situ measurements of aerosol physical and optical properties, resulting in more than 20 long-term (> 10 yr aerosol measurement sites in the Northern Hemisphere and Antarctica. Most of these sites are located at remote locations and monitor the aerosol particle number concentration, wavelength-dependent light scattering, backscattering, and absorption coefficients. The existence of these multi-year datasets enables the analysis of long-term trends of these aerosol parameters, and of the derived light scattering Ångström exponent and backscatter fraction. Since the aerosol variables are not normally distributed, three different methods (the seasonal Mann-Kendall test associated with the Sen's slope, the generalized least squares fit associated with an autoregressive bootstrap algorithm for confidence intervals, and the least-mean square fit applied to logarithms of the data were applied to detect the long-term trends and their magnitudes. To allow a comparison among measurement sites, trends on the most recent 10 and 15 yr periods were calculated. No significant trends were found for the three continental European sites. Statistically significant trends were found for the two European marine sites but the signs of the trends varied with aerosol property and location. Statistically significant decreasing trends for both scattering and absorption coefficients (mean slope of −2.0% yr−1 were found for most North American stations, although positive trends were found for a few desert and high-altitude sites. The difference in the timing of emission reduction policy for the Europe and US continents is a likely explanation for the decreasing trends in aerosol optical parameters found for most American sites compared to the lack of trends observed in Europe. No significant trends in scattering coefficient were found for the Arctic or Antarctic stations, whereas the Arctic station

  13. Enhancing optical absorption of metal–organic frameworks for improved visible light photocatalysis

    NARCIS (Netherlands)

    Nasalevich, M.A.; Goesten, M.G.; Savenije, T.J.; Kapteijn, F.; Gascon, J.

    2013-01-01

    NH2-MIL-125(Ti) has been post-synthetically functionalized with dye-like molecular fragments. The new material (methyl red-MIL- 125(Ti)) exhibits improved light absorption over a wide range of the visible spectrum, and shows enhanced photocatalytic oxidation activity under visible light illumination

  14. Expected Improvements in the Quantitative Remote Sensing of Optically Complex Waters with the Use of an Optically Fast Hyperspectral Spectrometer—A Modeling Study

    Directory of Open Access Journals (Sweden)

    Wesley J. Moses

    2015-03-01

    Full Text Available Using simulated data, we investigated the effect of noise in a spaceborne hyperspectral sensor on the accuracy of the atmospheric correction of at-sensor radiances and the consequent uncertainties in retrieved water quality parameters. Specifically, we investigated the improvement expected as the F-number of the sensor is changed from 3.5, which is the smallest among existing operational spaceborne hyperspectral sensors, to 1.0, which is foreseeable in the near future. With the change in F-number, the uncertainties in the atmospherically corrected reflectance decreased by more than 90% across the visible-near-infrared spectrum, the number of pixels with negative reflectance (caused by over-correction decreased to almost one-third, and the uncertainties in the retrieved water quality parameters decreased by more than 50% and up to 92%. The analysis was based on the sensor model of the Hyperspectral Imager for the Coastal Ocean (HICO but using a 30-m spatial resolution instead of HICO’s 96 m. Atmospheric correction was performed using Tafkaa. Water quality parameters were retrieved using a numerical method and a semi-analytical algorithm. The results emphasize the effect of sensor noise on water quality parameter retrieval and the need for sensors with high Signal-to-Noise Ratio for quantitative remote sensing of optically complex waters.

  15. Expected Improvements in the Quantitative Remote Sensing of Optically Complex Waters with the Use of an Optically Fast Hyperspectral Spectrometer—A Modeling Study

    Science.gov (United States)

    Moses, Wesley J.; Bowles, Jeffrey H.; Corson, Michael R.

    2015-01-01

    Using simulated data, we investigated the effect of noise in a spaceborne hyperspectral sensor on the accuracy of the atmospheric correction of at-sensor radiances and the consequent uncertainties in retrieved water quality parameters. Specifically, we investigated the improvement expected as the F-number of the sensor is changed from 3.5, which is the smallest among existing operational spaceborne hyperspectral sensors, to 1.0, which is foreseeable in the near future. With the change in F-number, the uncertainties in the atmospherically corrected reflectance decreased by more than 90% across the visible-near-infrared spectrum, the number of pixels with negative reflectance (caused by over-correction) decreased to almost one-third, and the uncertainties in the retrieved water quality parameters decreased by more than 50% and up to 92%. The analysis was based on the sensor model of the Hyperspectral Imager for the Coastal Ocean (HICO) but using a 30-m spatial resolution instead of HICO’s 96 m. Atmospheric correction was performed using Tafkaa. Water quality parameters were retrieved using a numerical method and a semi-analytical algorithm. The results emphasize the effect of sensor noise on water quality parameter retrieval and the need for sensors with high Signal-to-Noise Ratio for quantitative remote sensing of optically complex waters. PMID:25781507

  16. An Improved Treatment of Optics in the Lindquist-Wheeler Models

    CERN Document Server

    Clifton, Timothy; O'Donnell, Kane

    2012-01-01

    We consider the optical properties of Lindquist-Wheeler (LW) models of the Universe. These models consist of lattices constructed from regularly arranged discrete masses. They are akin to the Wigner-Seitz construction of solid state physics, and result in a dynamical description of the large-scale Universe in which the global expansion is given by a Friedmann-like equation. We show that if these models are constructed in a particular way then the redshifts of distant objects, as well as the dynamics of the global space-time, can be made to be in good agreement with the homogeneous and isotropic Friedmann-Lemaitre-Robertson-Walker (FLRW) solutions of Einstein's equations, at the level of <3% out to z~2. Angular diameter and luminosity distances, on the other hand, differ from those found in the corresponding FLRW models, while being consistent with the 'empty beam' approximation, together with the shearing effects due to the nearest masses. This can be compared with the large deviations found from the corre...

  17. Improved Imaging of Magnetically Labeled Cells Using Rotational Magnetomotive Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Peter Cimalla

    2017-04-01

    Full Text Available In this paper, we present a reliable and robust method for magnetomotive optical coherence tomography (MM-OCT imaging of single cells labeled with iron oxide particles. This method employs modulated longitudinal and transverse magnetic fields to evoke alignment and rotation of anisotropic magnetic structures in the sample volume. Experimental evidence suggests that magnetic particles assemble themselves in elongated chains when exposed to a permanent magnetic field. Magnetomotion in the intracellular space was detected and visualized by means of 3D OCT as well as laser speckle reflectometry as a 2D reference imaging method. Our experiments on mesenchymal stem cells embedded in agar scaffolds show that the magnetomotive signal in rotational MM-OCT is significantly increased by a factor of ~3 compared to previous pulsed MM-OCT, although the solenoid’s power consumption was 16 times lower. Finally, we use our novel method to image ARPE-19 cells, a human retinal pigment epithelium cell line. Our results permit magnetomotive imaging with higher sensitivity and the use of low power magnetic fields or larger working distances for future three-dimensional cell tracking in target tissues and organs.

  18. ZnS films for infrared optical coatings: improvement of adhesion to Ge substrates

    Science.gov (United States)

    Sánchez-Agudo, M.; Génova, I.; Orr, H. J. B.; Harris, G.; Pérez, G.

    2008-09-01

    In this work, physical and optical properties of ZnS films grown at different evaporation conditions have been studied. ZnS 3000 nm thick films have been deposited on Ge substrates at 200°C, 120°C and without substrate heating. In addition, evaporation rates of 4, 2 and 1 nm/s have been considered. The structural and morphological properties of the films have been analysed by XRD and AFM, respectively and the refractive index in the 2.4-11.5 microns range has been determined from transmittance spectra through reverse synthesis. From this analysis, the most suitable evaporation conditions for ZnS thin films deposition have been defined in terms of film properties and intended applications on thermal IR multilayer coatings. Afterwards, adhesion properties of ZnS films deposited under the optimised conditions have been analysed. ZnS films deposited at 120°C and 4 nm/s peeled off when subjected to MIL-F-48616 standard surface durability testing. The use of a MgO bonding layer to enhance the ZnS film adherence to the substrate has been proposed and its effect on the ZnS film properties has been studied. Finally, the mechanical stability of the ZnS coating under MIL-F-48616 standard testing has been confirmed for films grown onto MgO coated substrates.

  19. Improvement of plastic optical fiber microphone based on moisture pattern sensing in devoiced breath

    Science.gov (United States)

    Taki, Tomohito; Honma, Satoshi; Morisawa, Masayuki; Muto, Shinzo

    2008-03-01

    Conversation is the most practical and common form in communication. However, people with a verbal handicap feel a difficulty to produce words due to variations in vocal chords. This research leads to develop a new devoiced microphone system based on distinguishes between the moisture patterns for each devoiced breaths, using a plastic optical fiber (POF) moisture sensor. In the experiment, five POF-type moisture sensors with fast response were fabricated by coating swell polymer with a slightly larger refractive index than that of fiber core and were set in front of mouth. When these sensors are exposed into humid air produced by devoiced breath, refractive index in cladding layer decreases by swelling and then the POF sensor heads change to guided type. Based on the above operation principle, the output light intensities from the five sensors set in front of mouth change each other. Using above mentioned output light intensity patterns, discernment of devoiced vowels in Japanese (a,i,u,e,o) was tried by means of DynamicProgramming-Matching (DP-matching) method. As the result, distinction rate over 90% was obtained to Japanese devoiced vowels. Therefore, using this system and a voice synthesizer, development of new microphone for the person with a functional disorder in the vocal chords seems to be possible.

  20. Improving optical performance of concentrator cells by means of a deposited nanopattern layer

    Energy Technology Data Exchange (ETDEWEB)

    García-Linares, Pablo, E-mail: pablo.garcia-linares@cea.fr; Besson, Pierre; Weick, Clément; Baudrit, Mathieu [CEA-LITEN, Laboratoire de Photovoltaïque à Concentration, INES, Le Bourget du Lac (France); Dominguez, César [CEA-LITEN, Laboratoire de Photovoltaïque à Concentration, INES, Le Bourget du Lac (France); Instituto de Energía Solar - Universidad Politécnica de Madrid, Madrid (Spain); Dellea, Olivier [CEA-LITEN, Laboratoire de Surfaces Nanostructurées, Grenoble (France); Kämpfe, Thomas; Jourlin, Yves [Laboratoire Hubert Curien UMR CNRS, Université de Lyon, St. Etienne (France)

    2015-09-28

    Multijunction solar cells (MJSC) use anti-reflective coatings (ARC) to minimize Fresnel reflection losses for a family of light incidence angles. These coatings adapt the refractive index of the cell to that of the surrounding medium. Patterns with sizes in the range of the light wavelength can be used to further reduce reflections through diffraction. Transparent nanopatterns with a gradual profile, called moth-eye nanostructures, can adapt the refractive index of the optical interfaces (often with n∼1.5) used to encapsulate concentrator solar cells to that of the air (n{sub air}∼1). Here we show the effect of a nanometric moth-eye ARC with a round motif deposited on commercial MJSC that achieves short-circuit current (I{sub SC}) gains greater than 2% at normal incidence and even higher in the case of tilted illumination. In this work, MJSC with different moth-eye ARC are characterized under quantum efficiency (QE) as well as under concentrated illumination I-V in order to assess their potential. Simulations based on coupled wave analysis (RCWA) are used to fit the experimental results with successful results.

  1. Improving Photovoltaic Energy Production with Fiber-Optic Distributed Temperature Sensing

    Science.gov (United States)

    Hausner, M. B.; Berli, M.

    2014-12-01

    The efficiency of solar photovoltaic (PV) generators declines sharply with increased temperatures. Peak solar exposure often occurs at the same time as peak temperatures, but solar PV installations are typically designed based on solar angle. In temperate areas, the peak temperatures may not be high enough to induce significant efficiency losses. In some of the areas with the greatest potential for solar development, however, summer air temperatures regularly reach 45 °C and PV panel temperatures exceed the air temperatures. Here we present a preliminary model of a PV array intended to optimize solar production in a hot and arid environment. The model begins with the diurnal and seasonal cycles in the angle and elevation of the sun, but also includes a meteorology-driven energy balance to project the temperatures of the PV panels and supporting structure. The model will be calibrated and parameterized using a solar array at the Desert Research Institute's (DRI) Renewable Energy Deployment and Display (REDD) facility in Reno, Nevada, and validated with a similar array at DRI's Las Vegas campus. Optical fibers will be installed on the PV panels and structural supports and interrogated by a distributed temperature sensor (DTS) to record the spatial and temporal variations in temperature. Combining the simulated panel temperatures, the efficiency-temperature relationship for the panels, and the known solar cycles at a site will allow us to optimize the design of future PV collectors (i.e., the aspect and angle of panels) for given production goals.

  2. Improved optical limiting performance of laser-ablation-generated metal nanoparticles due to silica-microsphere-induced local field enhancement

    OpenAIRE

    Zheren Du; Lianwei Chen; Tsung-Sheng Kao; Mengxue Wu; Minghui Hong

    2015-01-01

    For practical application, optical limiting materials must exhibit a fast response and a low threshold in order to be used for the protection of the human eye and electro-optical sensors against intense light. Many nanomaterials have been found to exhibit optical limiting properties. Laser ablation offers the possibility of fabricating nanoparticles from a wide range of target materials. For practical use of these materials, their optical limiting performance, including optical limiting thres...

  3. An Arthrobacter spp. bacteremia leading to fetal death and maternal disseminated intravascular coagulation.

    Science.gov (United States)

    Shigeta, Naoya; Ozaki, Kimiaki; Hori, Kensuke; Ito, Kimihiko; Nakayama, Masahiro; Nakahira, Kumiko; Yanagihara, Itaru

    2013-02-01

    A 34-year-old parous woman developed high fever and threatened preterm labor after a 1-day trip, for which she was receiving prenatal care at a hospital. Three days after onset, at 24 4/7 weeks of gestation, she was transferred to our hospital in an emergency. Soon after the woman's arrival at our hospital, the infant was spontaneously stillborn via a transvaginal delivery. Laboratory tests revealed severe maternal disseminated intravascular coagulation with renal and liver insufficiency. Histopathologic examination of the placenta revealed vast fibrin deposition and remarkable neutrophilic infiltration in the intervillous space, suggesting a rare bacterial infection caused by Arthrobacter spp. The bacteria were predominantly detected in the placenta and maternal blood serum by common bacterial 16S rRNA sequencing after polymerase chain reaction amplification. We report the first case, to our knowledge, of bacteremia with Arthrobacter spp., which may lead to maternal disseminated intravascular coagulation and intrauterine fetal death.

  4. Distal polyneuropathy after canine heartworm disease therapy complicated by disseminated intravascular coagulation.

    Science.gov (United States)

    Dillon, A R; Braund, K G

    1982-08-01

    A 3-year-old male Setter-type dog had a progressive distal sensorimotor polyneuropathy characterized by weakness, bilateral atrophy of distal appendicular musculature, and reduced response to tactile stimuli. The diagnosis of a distal axonopathy was supported by electromyographic findings of fibrillation potentials, positive sharp waves in distal limb muscles, and absence of evoked action potentials, myopathic changes of atrophic angular fibers, and myelinated nerve fiber depletion in distal parts of peripheral nerves. The neuropathy appeared 5 weeks after 38 days of heparin therapy for disseminated intravascular coagulation. The disseminated intravascular coagulation, a complication of thiacetarsamide therapy for heartworm disease, had resolved 40 days after the end of heparin therapy. The cause of the neuropathy was not determined.

  5. Regression of coronary atherosclerosis by simvastatin: a serial intravascular ultrasound study

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Thayssen, Per; Pedersen, Knud Erik;

    2004-01-01

    BACKGROUND: Angiography of the coronary arteries reflects only changes in luminal dimensions. With intravascular ultrasound, cross-sectional images can be obtained and area measurements can be added to calculate volumes of the external elastic membrane (EEM), plaque plus media (P+M), and lumen...... in a not previously revascularized coronary artery, serial intravascular ultrasound studies with an ECG-triggered pullback were performed at baseline, after 3 months on a lipid-lowering diet, and after another 12 months on simvastatin 40 mg/d. Mean length of the analyzed atherosclerotic segments was 5.9+/-3.3 mm.......2+/-0.7 mmol/L, Ptherapy with simvastatin for 12 months is associated with a significant P+M regression in coronary arteries measured as reduction in P+M and EEM volumes without any...

  6. Effect of catecholamines and insulin on plasma volume and intravascular mass of albumin in man

    DEFF Research Database (Denmark)

    Hilsted, J; Christensen, N J; Larsen, S

    1989-01-01

    1. The effect of intravenous catecholamine infusions and of intravenous insulin on plasma volume and intravascular mass of albumin was investigated in healthy males. 2. Physiological doses of adrenaline (0.5 microgram/min and 3 microgram/min) increased peripheral venous packed cell volume...... significantly; intravenous noradrenaline at 0.5 microgram/min had no effect on packed cell volume, whereas packed cell volume increased significantly at 3 micrograms of noradrenaline/min. No significant change in packed cell volume was found during saline infusion. 3. During adrenaline infusion at 6 micrograms...... in packed cell volume, plasma volume, intravascular mass of albumin and transcapillary escape rate of albumin during hypoglycaemia may be explained by the combined actions of adrenaline and insulin....

  7. Transbiliary intravascular ultrasound-guided diagnostic biopsy of an inaccessible pancreatic head mass

    Directory of Open Access Journals (Sweden)

    Jeffrey Forris Beecham Chick, MD, MPH, DABR

    2017-06-01

    Full Text Available Percutaneous image-guided biopsies of pancreatic malignancies may prove challenging and nondiagnostic due to a variety of anatomic considerations. For patients with complex post-surgical anatomy, such as a Roux-en-Y gastric bypass, diagnosis via endoscopic ultrasound with fine-needle aspiration may not be possible because of an inability to reach the proximal duodenum. This report describes the first diagnostic case of transbiliary intravascular ultrasound-guided biopsy of a pancreatic head mass in a patient with prior Roux-en-Y gastric bypass for which a diagnosis could not be achieved via percutaneous and endoscopic approaches. Transbiliary intravascular ultrasound-guided biopsy resulted in a diagnosis of pancreatic adenocarcinoma, allowing the initiation of chemotherapy.

  8. Improved fiber-optic link for the phase reference distribution system for the TESLA technology based projects

    Science.gov (United States)

    Czuba, Krzysztof; Felber, Matthias

    2005-09-01

    The UV Free-Electron Laser (UVFEL) [1], The X-Ray Free-Electron Laser (XFEL) [2] and The International Linear Accelerator (ILC) [9] projects will require phase synchronization of various RF frequency subsystems on kilometer distances with accuracy better than 1ps. To fulfill these requirements, a phase reference distribution system concept was proposed and a prototype was developed for tests in the TESLA Test Facility 2 (TTF2). An important part of the phase reference system is the fiber-optic phase stable, long distance link described in this paper. An interferometrical scheme with feedback on phase, suppressing long term phase drifts induced by temperature changes was developed and tested in laboratory and under accelerator conditions. A motorized optical delay line was used in the system to compensate for phase errors. Described are error considerations and most important project issues like the hardware development and the real time phase controller software. The presented measurement results satisfy the design requirements. Experience gained during the experiments yielded proposals for system improvements.

  9. Improvement of diffraction efficiency of three-dimensional magneto-optic spatial light modulator with magnetophotonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, K.; Takagi, H., E-mail: takagi@ee.tut.ac.jp; Lim, P. B.; Inoue, M., E-mail: inoue@tut.ac.jp [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441 8580 (Japan); Goto, Taichi [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441 8580 (Japan); JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Horimai, H. [HolyMine Corporation, Atsugi, Kanagawa 243 0813 (Japan); Yoshikawa, H. [Department of Computer Engineering, College of Science and Technology, Nihon University, Funabashi, Chiba 274 8501 (Japan); Bove, V. M. [MIT Media Lab, Cambridge, Massachusetts 02139 (United States)

    2016-01-11

    We have developed three-dimensional magneto-optic spatial light modulators (3D-MOSLMs) that use magnetic domains as submicron scale pixels to represent holograms. Our display system uses a submicron-scale magnetic pixel array on an amorphous TbFe film to create a wide viewing angle hologram. However, in previous work the reconstructed images had a low intensity and a low optical contrast; brightness of the reconstructed image was 4.4 × 10{sup −2 }cd/m{sup 2} with 532 nm illumination light at 10.8 mW/cm{sup 2}, while display standard ISO13406 recommends 100 cd/m{sup 2} or more. In this paper, we describe our development of a 3D-MOSLM composed of an artificial magnetic lattice structure of magnetophotonic crystals (MPCs). The MPCs enhance the diffraction efficiency of reconstructed 3D images and reduce the power consumption for controlling the magnetic pixels by a light localization effect. We demonstrate reconstructed 3D images using the MPC and show significant brightness improvement.

  10. Moldable AR microstructures for improved laser transmission and damage resistance in CIRCM fiber optic beam delivery systems

    Science.gov (United States)

    MacLeod, Bruce D.; Hobbs, Douglas S.; Sabatino, Ernest, III

    2011-06-01

    Anti-reflecting (AR) surface relief microstructures (ARMs) are being developed as a replacement for thin-film AR coatings in laser-based systems to improve light transmission, power handling, operational bandwidth, and system reliability. Because ARMs textures have the potential to be replicated using simple embossing methods, the performance advantage and robustness of ARMs can be extended to moldable mid-infrared transmitting materials such as chalcogenide optical fibers. In this work, the optical performance of mid-infrared transparencies incorporating ARMs textures replicated from a master template has been modeled, and multiple master stamping tools have been fabricated in materials such as diamond, silicon carbide, nickel, silicon, and sapphire. Images from ARMs texture embossing trials using arsenic sulfide and arsenic selenide (AMTIR2) glasses, and fluoride glasses such as ZBLAN and indium fluoride provided by IRPhotonics, show excellent pattern transfer and fidelity. Transmission measurements of ARMs textures stamped into arsenic sulfide and arsenic selenide windows show broadband infrared performance equivalent to ARMs textured windows processed by direct patterning and etch methods. A system for molding ARMs textures directly into the end facets of multi-mode mid-infrared transmitting fibers is yielding promising initial results.

  11. Improved identification of the solution space of aerosol microphysical properties derived from the inversion of profiles of lidar optical data, part 2: simulations with synthetic optical data.

    Science.gov (United States)

    Kolgotin, Alexei; Müller, Detlef; Chemyakin, Eduard; Romanov, Anton

    2016-12-01

    We developed a mathematical scheme that allows us to improve retrieval products obtained from the inversion of multiwavelength Raman/HSRL lidar data, commonly dubbed "3 backscatter+2 extinction" (3β+2α) lidar. This scheme works independently of the automated inversion method that is currently being developed in the framework of the Aerosol-Cloud-Ecosystem (ACE) mission and which is successfully applied since 2012 [Atmos. Meas. Tech.7, 3487 (2014)10.5194/amt-7-3487-2014; "Comparison of aerosol optical and microphysical retrievals from HSRL-2 and in-situ measurements during DISCOVER-AQ 2013 (California and Texas)," in International Laser Radar Conference, July 2015, paper PS-C1-14] to data collected with the first airborne multiwavelength 3β+2α high spectral resolution lidar (HSRL) developed at NASA Langley Research Center. The mathematical scheme uses gradient correlation relationships we presented in part 1 of our study [Appl. Opt.55, 9839 (2016)APOPAI0003-693510.1364/AO.55.009839] in which we investigated lidar data products and particle microphysical parameters from one and the same set of optical lidar profiles. For an accurate assessment of regression coefficients that are used in the correlation relationships we specially designed the proximate analysis method that allows us to search for a first-estimate solution space of particle microphysical parameters on the basis of a look-up table. The scheme works for any shape of particle size distribution. Simulation studies demonstrate a significant stabilization of the various solution spaces of the investigated aerosol microphysical data products if we apply this gradient correlation method in our traditional regularization technique. Surface-area concentration can be estimated with an uncertainty that is not worse than the measurement error of the underlying extinction coefficients. The retrieval uncertainty of the effective radius is as large as ±0.07  μm for fine mode particles and approximately

  12. Aerosol decadal trends – Part 1: In-situ optical measurements at GAW and IMPROVE stations

    Directory of Open Access Journals (Sweden)

    B. A. Schichtel

    2012-08-01

    Full Text Available Currently many ground-based atmospheric stations include in-situ measurements of aerosol physical and optical properties, resulting in more than 20 long-term (>10 yr aerosol measurement sites in the Northern Hemisphere and Antarctica. Most of these sites are located at remote locations and monitor the aerosol particle number concentration, wavelength-dependent light scattering, backscattering, and absorption coefficients. The existence of these multi-year datasets enables the analysis of long-term trends of these aerosol parameters of the derived light scattering Ångström exponent and backscatter fraction. Since the aerosol variables are not normally distributed, three different methods (the seasonal Mann-Kendall test associated with the Sen's slope, the generalized least squares fit associated with an autoregressive bootstrap algorithm for confidence intervals, and the least-mean square fit applied to logarithms of the data were applied to detect the long-term trends and their magnitudes for each month. To allow a comparison among measurement sites with varying length of data records, trends on the most recent 10 and 15 yr periods were calculated. No significant trends were found for the three continental European sites. Statistically significant trends were found for the two European marine sites but the signs of the trends varied with aerosol property and location. Statistically significant decreasing trends for both scattering and absorption coefficient were found for most North American stations, although positive trends were found for a few desert and high-altitude sites. No significant trends in scattering coefficient were found for the Arctic or Antarctic stations, whereas the Arctic station had a negative trend in absorption coefficient.

  13. High resolution aerosol optical thickness retrieval over the Pearl River Delta region with improved aerosol modelling

    Institute of Scientific and Technical Information of China (English)

    WONG; ManSing; NICHOL; Janet; LEE; Kwon; Ho

    2009-01-01

    Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, a new aerosol retrieval algorithm using the MODIS 500 m resolution images is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta region. The rationale of our technique is to first estimate the aerosol reflectance by decomposing the top-of-atmosphere reflectance from surface reflectance and Rayleigh path reflectance. For the determination of surface reflectance, a modified Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. A strong correlation is shown between the surface reflectance of MRT images and MODIS land surface reflectance products (MOD09), with a value of 0.9. For conversion of aerosol reflectance to Aerosol Optical Thickness (AOT), comprehensive Look Up Tables (LUT) are constructed, in which aerosol properties and sun-viewing geometry in the radiative transfer calculations are taken into account. Four aerosol types, namely mixed urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on three years of AERONET measurements in Hong Kong. Their aerosol properties were input for LUT calculation. The resulting 500 m AOT images are highly correlated (r = 0.89) with AERONET sunphotometer observations in Hong Kong. This study demonstrates the applicability of aerosol retrieval at fine resolution scale in urban areas, which can assist the study of aerosol loading distribution and the impact of localized and transient pollution on urban air quality. In addition, the MODIS 500 m AOT images can be used to study cross

  14. High resolution aerosol optical thickness retrieval over the Pearl River Delta region with improved aerosol modelling

    Institute of Scientific and Technical Information of China (English)

    WONG ManSing; NICHOL Janet; LEE Kwon Ho; LI ZhanQing

    2009-01-01

    Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, a new aerosol retrieval algorithm using the MODIS 500 m resolu-tion images is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta re-gion. The rationale of our technique is to first estimate the aerosol reflectance by decomposing the top-of-atmosphere reflectance from surface reflectance and Rayleigh path reflectance. For the deter-mination of surface reflectance, a modified Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. A strong correlation is shown between the surface reflec-tance of MRT images and MODIS land surface reflectance products (MOD09), with a value of 0.9. For conversion of aerosol reflectance to Aerosol Optical Thickness (AOT), comprehensive Look Up Tables (LUT) are constructed, in which aerosol properties and sun-viewing geometry in the radiative transfer calculations are taken into account. Four aerosol types, namely mixed urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on three years of AERONET measurements in Hong Kong. Their aerosol properties were input for LUT calculation. The resulting 500 m AOT images are highly correlated (r=0.89) with AERONET sunphotometer observations in Hong Kong. This study demonstrates the applicability of aerosol retrieval at fine resolution scale in urban areas, which can assist the study of aerosol loading distribution and the impact of localized and transient pollution on urban air quality. In addition, the MODIS 500 m AOT images can be used to study cross

  15. The loss of homeostasis in hemostasis: new approaches in treating and understanding acute disseminated intravascular coagulation in critically ill patients.

    Science.gov (United States)

    Hook, Karen M; Abrams, Charles S

    2012-02-01

    Disseminated intravascular coagulation (DIC) profoundly increases the morbidity and mortality of patients who have sepsis. Both laboratory and clinical research advanced the understanding of the biology and pathophysiology of DIC. This, in turn, gave rise to improved therapies and patient outcomes. Beginning with a stimulus causing disruption of vascular integrity, cytokines and chemokines cause activation of systemic coagulation and inflammation. Seemingly paradoxically, the interplay between coagulation and inflammation also inhibits endogenous anticoagulants, fibrinolytics, and antiinflammatory pathways. The earliest documented and best-studied microbial cause of DIC is the lipopolysaccharide endotoxin of Gram-negative bacteria. Extensive microvascular thrombi emerge in the systemic vasculature due to dysregulation of coagulation. The result of this unrestrained, widespread small vessel thromboses multiorgan system failure. Consumption of platelets and coagulation factors during this process can lead to an elevated risk of hemorrhage. The management of these patients with simultaneous hemorrhage and thrombosis is complex and challenging. Definitive treatment of DIC, and attenuation of end-organ damage, requires control of the inciting cause. Currently, activated protein C is the only approved therapy in the United States for sepsis complicated by DIC. Further research is needed in this area to improve clinical outcomes for patients with sepsis.

  16. Supervised domain adaptation of decision forests: Transfer of models trained in vitro for in vivo intravascular ultrasound tissue characterization.

    Science.gov (United States)

    Conjeti, Sailesh; Katouzian, Amin; Roy, Abhijit Guha; Peter, Loïc; Sheet, Debdoot; Carlier, Stéphane; Laine, Andrew; Navab, Nassir

    2016-08-01

    In this paper, we propose a supervised domain adaptation (DA) framework for adapting decision forests in the presence of distribution shift between training (source) and testing (target) domains, given few labeled examples. We introduce a novel method for DA through an error-correcting hierarchical transfer relaxation scheme with domain alignment, feature normalization, and leaf posterior reweighting to correct for the distribution shift between the domains. For the first time we apply DA to the challenging problem of extending in vitro trained forests (source domain) for in vivo applications (target domain). The proof-of-concept is provided for in vivo characterization of atherosclerotic tissues using intravascular ultrasound signals, where presence of flowing blood is a source of distribution shift between the two domains. This potentially leads to misclassification upon direct deployment of in vitro trained classifier, thus motivating the need for DA as obtaining reliable in vivo training labels is often challenging if not infeasible. Exhaustive validations and parameter sensitivity analysis substantiate the reliability of the proposed DA framework and demonstrates improved tissue characterization performance for scenarios where adaptation is conducted in presence of only a few examples. The proposed method can thus be leveraged to reduce annotation costs and improve computational efficiency over conventional retraining approaches.

  17. MRI evaluation and follow-up of bone necrosis after meningococcal infection and disseminated intravascular coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Damry, N. (Dept. of Radiology, Hopital Universitaire des Enfants Reine Fabiola, Brussels (Belgium)); Schurmans, T. (Dept. of Peadiatrics, Hopital Universitaire des Enfants Reine Fabiola, Brussels (Belgium)); Perlmutter, N. (Dept. of Radiology, Hopital Universitaire des Enfants Reine Fabiola, Brussels (Belgium))

    1993-10-01

    Disseminated intravascular coagulation (DIC) is a serious complication of meningococcal septicaemia. It often results in infarction of various tissues namely the skin, adrenal glands, kidneys, brain and, much less commonly, bones. We describe a patient who presented bone lesions after meningococcal septicaemia. In addition to plain radiography and scintigraphy the lesions were evaluated with MRI and have proved to be extensive and still progressive, approxximately 18 months after the onset of the disease. (orig.)

  18. [Evaluation of the severity course and prognosis of disseminated intravascular blood coagulation syndrome].

    Science.gov (United States)

    Kinakh, M V; Chaplyk, V V; Fedchyshyn, N R

    2009-01-01

    Activation of the peroxidal oxidation of lipids (POL) processes with its primary and secondary products levels raising constitutes a favourable sign, according to data of examination of 66 patients, suffering different phases of disseminated intravascular blood coagulation syndrome (DIBCS). The POL products contents reduction (areactive course) characterizes the process severity and constitutes an unfavourable prognostical sign. The areactive course rate is the highest in the patients, suffering DIBCS, phase III.

  19. THROMBOPHILIA AND INTENSITY OF THE INTRAVASCULAR MICROCOAGULATION IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE, ATHEROTHROMBOSIS

    Directory of Open Access Journals (Sweden)

    E. A. Shelest

    2015-09-01

    Full Text Available Aim. To study the intensity of the intravascular microcoagulation in patients with atherothrombosis (AT, chronic obstructive pulmonary disease (COPD and thrombophilia.Material and methods. 115 patients were enrolled into the study: 37 patients with COPD (22 with thrombophilia and 15 without thrombophilia; 37 patients with AT (23 with thrombophilia and 14 without thrombophilia; 41 patients with COPD+AT (24 with thrombophilia and 17 without thrombophilia. In the control group 53 healthy people (39 with thrombophilia and 14 without thrombophilia were included. Median age was 62 (56.5, 69 years. The intensity of intravascular microcoagulation was measured: platelet factor 4 (PF4 by ELISA, D-dimer by ELISA, XIIa-dependent fibrinolysis (time. Polymerase chain reaction was used for detection of such trombophilia parameters as Leiden mutation, prothrombin gene mutation 20210A, mutation in the gene of methylenetetrahydrofolate reductase (MTHFR and plasminogen activator inhibitor-1 (PAI-1.Results. The level of PF4 and D-dimer was significantly higher while fibrinolytic activity was lower in COPD (103.5 ME/ml, 70 ng/ml, 650 s, respectively, AT (127.1 ME/ml, 96,9 ng/ml, 850 s, respectively and COPD+AT (136.5 ME/ml, 106.5 ng/ml, 1148 s, respectively groups as compared with the control group (p<0.05. When analyzing the level of intravascular coagulation parameters in patients with thrombophilia and without it, levels of PF4, D-dimer and XIIa-dependent fibrinolysis (time were significantly higher in thrombophilia subgroups among all patients (p<0.05. In patients with thrombophilia levels of these parameters were significantly higher in those with two or more thrombophilia gene polymorphisms than with one (p<0.01.Conclusion. The intensity of intravascular microcoagulation increases in patients with thrombophilia, atherothrombosis and COPD.

  20. Study of restenosis in drug eluting stents: new insights from greyscale intravascular ultrasound and virtual histology.

    Science.gov (United States)

    Garcia-Garcia, Hector M; Shen, Zhujun; Piazza, Nicolo

    2009-05-01

    In current cardiology practice, many patients undergo secondary revascularisation due to reduced long-term vein graft patency or in-stent restenosis. In this report, we describe causes of drug-eluting stent restenosis identifiable by intravascular ultrasound imaging (IVUS) and variables related to restenosis used for reporting greyscale IVUS. In addition, IVUS findings in bypass grafts and the long-term results after stent implantation are provided. Finally, the usefulness of IVUS virtual histology for the study of restenosis is described.