Science.gov

Sample records for real-time intraocular pressure

  1. [Intraocular pressure in phacoemulsification].

    PubMed

    Synek, S; Synková, M; Skorkovská, S

    2002-01-01

    The authors investigated changes of the intraocular pressure after non-complicated phacoemulsification with implantation of an intraocular lens of different types (OMMA, silicone, Acrysof) in 40 patients. From the results it is obvious that in some patients already 4 hours after surgery the intraocular pressure rises to an average of 31 +/- 17 mm Hg. The magnitude of the intraocular pressure was not influenced by the size of the surgical wound nor the type of intraocular lens. In values below 30 mm Hg the authors recommend merely follow up of the patients as they assume that these values have a positive impact on closure of the tunnel incision. In the differential diagnosis it is important to consider the post-operative inflammatory reaction, the absorption reaction of residual viscoelastic material, pupillary block while the lenticular capsule is intact and undiagnosed glaucoma. In values above 30 mm Hg the authors recommend administration of beta-blockers, Diluran and antiphlogistics.

  2. Real-Time Retinal Vessel Mapping and Localization for Intraocular Surgery

    PubMed Central

    Becker, Brian C.; Riviere, Cameron N.

    2013-01-01

    Computer-aided intraocular surgery requires precise, real-time knowledge of the vasculature during retinal procedures such as laser photocoagulation or vessel cannulation. Because vitreoretinal surgeons manipulate retinal structures on the back of the eye through ports in the sclera, voluntary and involuntary tool motion rotates the eye in the socket and causes movement to the microscope view of the retina. The dynamic nature of the surgical workspace during intraocular surgery makes mapping, tracking, and localizing vasculature in real time a challenge. We present an approach that both maps and localizes retinal vessels by temporally fusing and registering individual-frame vessel detections. On video of porcine and human retina, we demonstrate real-time performance, rapid convergence, and robustness to variable illumination and tool occlusion. PMID:24488000

  3. Intraocular pressure reduction and regulation system

    NASA Technical Reports Server (NTRS)

    Baehr, E. F.; Burnett, J. E.; Felder, S. F.; Mcgannon, W. J.

    1979-01-01

    An intraocular pressure reduction and regulation system is described and data are presented covering performance in: (1) reducing intraocular pressure to a preselected value, (2) maintaining a set minimum intraocular pressure, and (3) reducing the dynamic increases in intraocular pressure resulting from external loads applied to the eye.

  4. Intraocular pressure reduction and regulation

    NASA Technical Reports Server (NTRS)

    Baehr, E. F.; Mcgannon, W. J.

    1979-01-01

    System designed to reduce intraocular pressure hydraulically to any level desired by physician over set time and in controlled manner has number of uses in ophthalmology. Device may be most immediately useful in treatment of glaucoma.

  5. Real-Time Detection of Dust Devils from Pressure Readings

    NASA Technical Reports Server (NTRS)

    Wagstaff, Kiri

    2009-01-01

    A method for real-time detection of dust devils at a given location is based on identifying the abrupt, temporary decreases in atmospheric pressure that are characteristic of dust devils as they travel through that location. The method was conceived for use in a study of dust devils on the Martian surface, where bandwidth limitations encourage the transmission of only those blocks of data that are most likely to contain information about features of interest, such as dust devils. The method, which is a form of intelligent data compression, could readily be adapted to use for the same purpose in scientific investigation of dust devils on Earth. In this method, the readings of an atmospheric- pressure sensor are repeatedly digitized, recorded, and processed by an algorithm that looks for extreme deviations from a continually updated model of the current pressure environment. The question in formulating the algorithm is how to model current normal observations and what minimum magnitude deviation can be considered sufficiently anomalous as to indicate the presence of a dust devil. There is no single, simple answer to this question: any answer necessarily entails a compromise between false detections and misses. For the original Mars application, the answer was sought through analysis of sliding time windows of digitized pressure readings. Windows of 5-, 10-, and 15-minute durations were considered. The windows were advanced in increments of 30 seconds. Increments of other sizes can also be used, but computational cost increases as the increment decreases and analysis is performed more frequently. Pressure models were defined using a polynomial fit to the data within the windows. For example, the figure depicts pressure readings from a 10-minute window wherein the model was defined by a third-degree polynomial fit to the readings and dust devils were identified as negative deviations larger than both 3 standard deviations (from the mean) and 0.05 mbar in magnitude. An

  6. [Intraocular pressure measurement in children].

    PubMed

    Bresson-Dumont, H

    2009-03-01

    Intraocular pressure (IOP) measurement in children is often difficult to perform because younger children are non-compliant and resisting the examination. Normal IOP in children is not well established yet because in the studies reporting about IOP, the instruments used and clinical conditions have varied. Non contact tonometer often overestimates IOP in blinking children and is not always reliable. But all the others measurement techniques use contact (GAT, Perkins, Tono-Pen, ORA, RBT), and are not always suitable and easy-touse. Under general anaesthesia, mean IOP measured with Perkins applanation tonometer is under 8 mmHg before age of 3 months and under 12 mmHg between ages of 6 and 9 months. After, IOP shows an increasing trend with age of 1 mmHg per year up to 12 years. Some studies have proposed as normal pediatric IOP: To=0.71 x age (years) +10, up to age 10. Then, IOP tends to approach adult levels by 12 years of age. However pediatric glaucoma is rare: congenital glaucoma, before age of 3 years, autosomal dominant juvenile glaucoma, with family history of glaucoma and elevated IOP, or secondary glaucoma with special context. Thus, hypertony has to be confirmed by another measurement technique, correlated to central corneal thickness, and clinical examination (optic nerve head and visual field). PMID:19515328

  7. 21 CFR 886.4280 - Intraocular pressure measuring device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Intraocular pressure measuring device. 886.4280... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4280 Intraocular pressure measuring device. (a) Identification. An intraocular pressure measuring device is a manual or AC-powered...

  8. 21 CFR 886.4280 - Intraocular pressure measuring device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Intraocular pressure measuring device. 886.4280... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4280 Intraocular pressure measuring device. (a) Identification. An intraocular pressure measuring device is a manual or AC-powered...

  9. 21 CFR 886.4280 - Intraocular pressure measuring device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Intraocular pressure measuring device. 886.4280... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4280 Intraocular pressure measuring device. (a) Identification. An intraocular pressure measuring device is a manual or AC-powered...

  10. 21 CFR 886.4280 - Intraocular pressure measuring device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular pressure measuring device. 886.4280... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4280 Intraocular pressure measuring device. (a) Identification. An intraocular pressure measuring device is a manual or AC-powered...

  11. Infant Botulism and Raised Intraocular Pressure.

    PubMed

    Eberly, Matthew D; Uber, Ian; Kieling, Christopher R; Birdsong, Richard H

    2009-11-01

    Infant botulism is an exceedingly rare disease. Because confirmatory laboratory testing is not available for several days after time of presentation, infant botulism remains a clinical diagnosis. The authors demonstrate how raised intraocular pressure may provide an additional clinical clue to making the diagnosis.

  12. Real-time strap pressure sensor system for powered exoskeletons.

    PubMed

    Tamez-Duque, Jesús; Cobian-Ugalde, Rebeca; Kilicarslan, Atilla; Venkatakrishnan, Anusha; Soto, Rogelio; Contreras-Vidal, Jose Luis

    2015-02-16

    Assistive and rehabilitative powered exoskeletons for spinal cord injury (SCI) and stroke subjects have recently reached the clinic. Proper tension and joint alignment are critical to ensuring safety. Challenges still exist in adjustment and fitting, with most current systems depending on personnel experience for appropriate individual fastening. Paraplegia and tetraplegia patients using these devices have impaired sensation and cannot signal if straps are uncomfortable or painful. Excessive pressure and blood-flow restriction can lead to skin ulcers, necrotic tissue and infections. Tension must be just enough to prevent slipping and maintain posture. Research in pressure dynamics is extensive for wheelchairs and mattresses, but little research has been done on exoskeleton straps. We present a system to monitor pressure exerted by physical human-machine interfaces and provide data about levels of skin/body pressure in fastening straps. The system consists of sensing arrays, signal processing hardware with wireless transmission, and an interactive GUI. For validation, a lower-body powered exoskeleton carrying the full weight of users was used. Experimental trials were conducted with one SCI and one able-bodied subject. The system can help prevent skin injuries related to excessive pressure in mobility-impaired patients using powered exoskeletons, supporting functionality, independence and better overall quality of life.

  13. Real-Time Strap Pressure Sensor System for Powered Exoskeletons

    PubMed Central

    Tamez-Duque, Jesús; Cobian-Ugalde, Rebeca; Kilicarslan, Atilla; Venkatakrishnan, Anusha; Soto, Rogelio; Contreras-Vidal, Jose Luis

    2015-01-01

    Assistive and rehabilitative powered exoskeletons for spinal cord injury (SCI) and stroke subjects have recently reached the clinic. Proper tension and joint alignment are critical to ensuring safety. Challenges still exist in adjustment and fitting, with most current systems depending on personnel experience for appropriate individual fastening. Paraplegia and tetraplegia patients using these devices have impaired sensation and cannot signal if straps are uncomfortable or painful. Excessive pressure and blood-flow restriction can lead to skin ulcers, necrotic tissue and infections. Tension must be just enough to prevent slipping and maintain posture. Research in pressure dynamics is extensive for wheelchairs and mattresses, but little research has been done on exoskeleton straps. We present a system to monitor pressure exerted by physical human-machine interfaces and provide data about levels of skin/body pressure in fastening straps. The system consists of sensing arrays, signal processing hardware with wireless transmission, and an interactive GUI. For validation, a lower-body powered exoskeleton carrying the full weight of users was used. Experimental trials were conducted with one SCI and one able-bodied subject. The system can help prevent skin injuries related to excessive pressure in mobility-impaired patients using powered exoskeletons, supporting functionality, independence and better overall quality of life. PMID:25690551

  14. Real-time strap pressure sensor system for powered exoskeletons.

    PubMed

    Tamez-Duque, Jesús; Cobian-Ugalde, Rebeca; Kilicarslan, Atilla; Venkatakrishnan, Anusha; Soto, Rogelio; Contreras-Vidal, Jose Luis

    2015-01-01

    Assistive and rehabilitative powered exoskeletons for spinal cord injury (SCI) and stroke subjects have recently reached the clinic. Proper tension and joint alignment are critical to ensuring safety. Challenges still exist in adjustment and fitting, with most current systems depending on personnel experience for appropriate individual fastening. Paraplegia and tetraplegia patients using these devices have impaired sensation and cannot signal if straps are uncomfortable or painful. Excessive pressure and blood-flow restriction can lead to skin ulcers, necrotic tissue and infections. Tension must be just enough to prevent slipping and maintain posture. Research in pressure dynamics is extensive for wheelchairs and mattresses, but little research has been done on exoskeleton straps. We present a system to monitor pressure exerted by physical human-machine interfaces and provide data about levels of skin/body pressure in fastening straps. The system consists of sensing arrays, signal processing hardware with wireless transmission, and an interactive GUI. For validation, a lower-body powered exoskeleton carrying the full weight of users was used. Experimental trials were conducted with one SCI and one able-bodied subject. The system can help prevent skin injuries related to excessive pressure in mobility-impaired patients using powered exoskeletons, supporting functionality, independence and better overall quality of life. PMID:25690551

  15. Primary cilia signaling mediates intraocular pressure sensation.

    PubMed

    Luo, Na; Conwell, Michael D; Chen, Xingjuan; Kettenhofen, Christine Insinna; Westlake, Christopher J; Cantor, Louis B; Wells, Clark D; Weinreb, Robert N; Corson, Timothy W; Spandau, Dan F; Joos, Karen M; Iomini, Carlo; Obukhov, Alexander G; Sun, Yang

    2014-09-01

    Lowe syndrome is a rare X-linked congenital disease that presents with congenital cataracts and glaucoma, as well as renal and cerebral dysfunction. OCRL, an inositol polyphosphate 5-phosphatase, is mutated in Lowe syndrome. We previously showed that OCRL is involved in vesicular trafficking to the primary cilium. Primary cilia are sensory organelles on the surface of eukaryotic cells that mediate mechanotransduction in the kidney, brain, and bone. However, their potential role in the trabecular meshwork (TM) in the eye, which regulates intraocular pressure, is unknown. Here, we show that TM cells, which are defective in glaucoma, have primary cilia that are critical for response to pressure changes. Primary cilia in TM cells shorten in response to fluid flow and elevated hydrostatic pressure, and promote increased transcription of TNF-α, TGF-β, and GLI1 genes. Furthermore, OCRL is found to be required for primary cilia to respond to pressure stimulation. The interaction of OCRL with transient receptor potential vanilloid 4 (TRPV4), a ciliary mechanosensory channel, suggests that OCRL may act through regulation of this channel. A novel disease-causing OCRL allele prevents TRPV4-mediated calcium signaling. In addition, TRPV4 agonist GSK 1016790A treatment reduced intraocular pressure in mice; TRPV4 knockout animals exhibited elevated intraocular pressure and shortened cilia. Thus, mechanotransduction by primary cilia in TM cells is implicated in how the eye senses pressure changes and highlights OCRL and TRPV4 as attractive therapeutic targets for the treatment of glaucoma. Implications of OCRL and TRPV4 in primary cilia function may also shed light on mechanosensation in other organ systems.

  16. Loop mediated isothermal amplification assay using hydroxy naphthol blue, conventional polymerase chain reaction and real-time PCR in the diagnosis of intraocular tuberculosis.

    PubMed

    Balne, P K; Basu, S; Rath, S; Barik, M R; Sharma, S

    2015-01-01

    This study is a comparative evaluation (Chi-square test) of a closed tube loop mediated isothermal amplification assay using hydroxy naphthol blue dye (HNB-LAMP), real-time polymerase chain reaction (PCR) and conventional PCR in the diagnosis of intraocular tuberculosis. Considering clinical presentation as the gold standard in 33 patients, the sensitivity of HNB-LAMP assay (75.8%) was higher (not significant, P value 0.2) than conventional PCR (57.6%) and lower than real-time PCR (90.9%). Specificity was 100% by all three methods. No amplification was observed in negative controls (n = 20) by all three methods. The cost of the HNB-LAMP assay was Rs. 500.00 and it does not require thermocycler, therefore, it can be used as an alternative to conventional PCR in resource-poor settings.

  17. Circadian rhythm of intraocular pressure in the adult rat.

    PubMed

    Lozano, Diana C; Hartwick, Andrew T E; Twa, Michael D

    2015-05-01

    Ocular hypertension is a risk factor for developing glaucoma, which consists of a group of optic neuropathies characterized by progressive degeneration of retinal ganglion cells and subsequent irreversible vision loss. Our understanding of how intraocular pressure damages the optic nerve is based on clinical measures of intraocular pressure that only gives a partial view of the dynamic pressure load inside the eye. Intraocular pressure varies over the course of the day and the oscillator regulating these daily changes has not yet been conclusively identified. The purpose of this study was to compare and contrast the circadian rhythms of intraocular pressure and body temperature in Brown Norway rats when these animals are housed in standard light-dark and continuous dim light (40-90 lux) conditions. The results from this study show that the temperature rhythm measured in continuous dim light drifted forward relative to external time, indicating that the rhythm was free running and being regulated by an internal biological clock. Also, the results show that there is a persistent, but dampened, circadian rhythm of intraocular pressure in continuous dim light and that the circadian rhythms of temperature and intraocular pressure are not synchronized by the same central oscillator. We conclude that once- or twice-daily clinical measures of intraocular pressure are insufficient to describe intraocular pressure dynamics. Similarly, our results indicate that, in experimental animal models of glaucoma, the common practice of housing animals in constant light does not necessarily eliminate the potential influence of intraocular pressure rhythms on the progression of nerve damage. Future studies should aim to determine whether an oscillator within the eye regulates the rhythm of intraocular pressure and to better characterize the impact of glaucoma on this rhythm.

  18. Development of an instrument for real-time computation of indicated mean effective pressure

    NASA Technical Reports Server (NTRS)

    Rice, W. J.

    1984-01-01

    A new instrument capable of computing in real time the per-cycle indicated mean effective pressure (IMEP) of internal combustion engines and compressors was designed and tested. The values of IMEP obtained with the new instrument were found to be in excellent agreement with values obtained by previous postrun data reduction techniques.

  19. New technologies for measuring intraocular pressure.

    PubMed

    Garcia-Feijoo, Julian; Martinez-de-la-Casa, Jose María; Morales-Fernandez, Laura; Saenz Frances, Federico; Santos-Bueso, Enrique; Garcia-Saenz, Sofia; Mendez-Hernandez, Carmen

    2015-01-01

    The level of intraocular pressure (IOP) is the main known risk factor for the development and progression of glaucomatous optic neuropathy. Despite Goldmann applanation tonometry (GAT) being the gold standard for determining IOP since the last century, its limitations were obvious from the start and include substantial effects of several eye variables such as axial length, curvature, rigidity, and corneal thickness. These limitations have prompted the development of numerous formulas and nomograms designed to compensate for the ocular characteristics effect on GAT, but none of these methods has been entirely satisfactory. Similarly, as a result of efforts to mitigate some of the limitations of conventional tonometry, several new tonometers have appeared on the scene. PMID:26518073

  20. A real-time pressure estimation algorithm for closed-loop combustion control

    NASA Astrophysics Data System (ADS)

    Al-Durra, Ahmed; Canova, Marcello; Yurkovich, Stephen

    2013-07-01

    The cylinder pressure is arguably the most important variable characterizing the combustion process in internal combustion engines. In light of the recent advances in combustion technologies and in engine control, the use of cylinder pressure is now frequently considered as a feedback signal for closed-loop combustion control algorithms. In order to generate an accurate pressure trace for real-time combustion control and diagnostics, the output of the in-cylinder pressure transducer must be conditioned with signal processing methods to mitigate the well-known issues of offset and noise. While several techniques have been proposed for processing the cylinder pressure signal with limited computational burden, most of the available methods still require one to apply low-pass filters or moving average windows in order to mitigate the noise. This ultimately limits the opportunity of exploiting the in-cylinder pressure feedback for a cycle-by-cycle control of the combustion process. To this extent, this paper presents an estimation algorithm that extracts the pressure signal from the in-cylinder sensor in real-time, allowing for estimating the 50% burn rate location and IMEP on a cycle-by-cycle basis. The proposed approach relies on a model-based estimation algorithm whose starting point is a crank-angle based engine combustion model that predicts the in-cylinder pressure from the definition of a burn rate function. Linear parameter varying (LPV) techniques are then used to expand the region of estimation to cover the engine operating map, as well as allowing for real-time cylinder estimation during transients. The estimator is tested on the experimental data collected on an engine dynamometer as well as on a high-fidelity engine simulator. The results obtained show the effectiveness of the estimator in reconstructing the cylinder pressure on a crank-angle basis and in rejecting measurement noise and modeling errors, with considerably low computation effort.

  1. Effects of Different Intensities of Exercise on Intraocular Pressure

    ERIC Educational Resources Information Center

    Rowe, Deryl; And Others

    1976-01-01

    The decrease in intraocular pressure during exercise and the first few minutes of recovery is related to a decrease in blood pH and an increase in blood lactate concentration, not to the intensity of the exercise. (MB)

  2. Relation between intraocular pressure and size of transverse sinuses.

    PubMed

    Kantarci, Mecit; Dane, Senol; Gumustekin, Kenan; Onbas, Omer; Alper, Fatih; Okur, Adnan; Aslankurt, Murat; Yazici, Ahmet Taylan

    2005-01-01

    There are asymmetries in the sizes of transverse sinus and intraocular pressure. The purpose of this study was to investigate possible relationships between the asymmetry of transverse sinuses in TOF MR venography and intraocular pressures of right and left eyes. In this study, subjects were 63 male and 42 female medical school students, aged 18-21 years (mean+/-SD; 19.72+/-0.67 years). Subjects with neurological and ophthalmologic disease, particularly dural sinus thrombosis, myopia, trauma and glaucoma, were excluded the study. Subjects were divided into five groups according to the magnitudes of the right- and left-transverse sinuses in MR venography results. There is a functional relation between intraocular pressures of the right and left eyes and asymmetry of the transverse sinus. If the transverse sinus on one side is larger and its venous drainage is greater, the intraocular pressure of the eye on this side is lower. It can be speculated that the transverse sinus size may be associated with pathogenesis of diseases with increased intraocular pressure such as glaucoma. We aim to determine the relation between the size and drainage of transverse sinuses in TOF MR venography and intraocular pressure in patients with open-angle glaucoma in our next study. PMID:15647949

  3. Noninvasive intraocular pressure monitoring: current insights

    PubMed Central

    De Smedt, Stefan

    2015-01-01

    Glaucoma is the second leading cause of blindness worldwide and intraocular pressure (IOP) is currently its only modifiable risk factor. Peak IOP has for a long time been considered as a major contributor to glaucoma progression, but its effects may depend not only on its magnitude, but also on its time course. The IOP is nowadays considered to be a dynamic parameter with a circadian rhythm and spontaneous changes. The current practice of punctual measuring the IOP during office hours is therefore a suboptimal approach, which does not take into account the natural fluctuation of IOP. Because of its static nature a single IOP measurement in sitting position fails to document the true range of an individual’s IOP, peak IOP, or variation throughout the day. Phasing means monitoring a patient’s IOP during the daytime or over a 24-hour period. This can provide additional information in the management of glaucoma patients. This review focuses on the current insight of non-invasive IOP monitoring as a method of obtaining more complete IOP profiles. Invasive techniques using an implantable sensor are beyond the scope of this review. PMID:26257509

  4. Real-time noninvasive estimation of intrapleural pressure in mechanically ventilated patients: a feasibility study.

    PubMed

    Albanese, Antonio; Karamolegkos, Nikolaos; Haider, Syed W; Seiver, Adam; Chbat, Nicolas W

    2013-01-01

    A method for real-time noninvasive estimation of intrapleural pressure in mechanically ventilated patients is proposed. The method employs a simple first-order lung mechanics model that is fitted in real-time to flow and pressure signals acquired non-invasively at the opening of the patient airways, in order to estimate lung resistance (RL), lung compliance (CL) and intrapleural pressure (Ppl) continuously in time. Estimation is achieved by minimizing the sum of squared residuals between measured and model predicted airway pressure using a modified Recursive Least Squares (RLS) approach. Particularly, two different RLS algorithms, namely the conventional RLS with Exponential Forgetting (EF-RLS) and the RLS with Vector-type Forgetting Factor (VFF-RLS), are considered in this study and their performances are first evaluated using simulated data. Simulations suggest that the conventional EF-RLS algorithm is not suitable for our purposes, whereas the VFF-RLS method provides satisfactory results. The potential of the VFF-RLS based method is then proved on experimental data collected from a mechanically ventilated pig. Results show that the method provides continuous estimated lung resistance and compliance in normal physiological ranges and pleural pressure in good agreement with invasive esophageal pressure measurements.

  5. Effects of 2-alkynyladenosine derivatives on intraocular pressure in rabbits.

    PubMed

    Konno, Takashi; Ohnuma, Shin-ya; Uemoto, Kazuhiro; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Endo, Kazuki; Hosokawa, Tomokazu; Nakahata, Norimichi

    2004-02-23

    We evaluated the activities of 2-alkynyladenosine derivatives, relatively selective adenosine A2 receptor agonists, in the intraocular pressure regulation in rabbits. An adenosine A2 receptor agonist 2-[p-(2-carboxyethyl)phenylethylamino]-5'-N-ethylcarboxamidoadenosine (CGS-21680) decreased intraocular pressure, while another A2 receptor agonist 2-(phenylamino)adenosine transiently increased it. The first group of 2-alkynyladenosine derivatives (1-hexyn-1-yl derivatives) caused a transient increase followed by decrease in intraocular pressure, while the second group (1-octyn-1-yl and 6-cyano-1-hexyn-1-yl derivatives) only decreased it. The second group is also effective in the ocular hypertensive models induced by water-loading and alpha-chymotrypsin. The outflow facility was increased by a 1-octyn-1-yl derivative. Both increase and decrease in intraocular pressure induced by 2-alkynyladenosine derivatives were inhibited by an adenosine A2 receptor antagonist 3,7-dimethyl-1-propargylxanthine, but not by an adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropyl xanthine. These findings suggest that 2-alkynyladenosine derivatives may affect intraocular pressure via adenosine A2 receptor, and 2-alkynyladenosine derivative-induced ocular hypotension is due to the increase of outflow facility.

  6. [Intraocular Pressure Sensor Based on a Contact Lens].

    PubMed

    Guo, Xuhong; Pet, Weihua; Yao, Zhaolin; Chen, Yuanfang; Hu, Xiaohui; Chen, Hongda; Zhu, Jingyuan; Wu, Huijuan

    2016-02-01

    Intraocular pressure detection has a great significance for understanding the status of eye health, prevention and treatment of diseases such as glaucoma. Traditional intraocular pressure detection needs to be held in the hospital. It is not only time-consuming to doctors and patients, but also difficult to achieve 24 hour-continuous detection. Microminiaturization of the intraocular pressure sensor and wearing it as a contact lens, which is convenient, comfortable and noninvasive, can solve this problem because the soft contact lens with an embedded micro fabricated strain gauge allows the measurement of changes in corneal curvature to correlate to variations of intraocular pressure. We fabricated a strain gauge using micro-electron mechanical systems, and integrated with the contact lens made of polydimethylsiloxane (PDMS) using injection molding. The experimental results showed that the sensitivity was 100. 7 µV/µm. When attached to the corneal surface, the average sensitivity of sensor response of intraocular pressure can be 125.8 µV/mm Hg under the ideal condition. PMID:27382734

  7. [Intraocular Pressure Sensor Based on a Contact Lens].

    PubMed

    Guo, Xuhong; Pet, Weihua; Yao, Zhaolin; Chen, Yuanfang; Hu, Xiaohui; Chen, Hongda; Zhu, Jingyuan; Wu, Huijuan

    2016-02-01

    Intraocular pressure detection has a great significance for understanding the status of eye health, prevention and treatment of diseases such as glaucoma. Traditional intraocular pressure detection needs to be held in the hospital. It is not only time-consuming to doctors and patients, but also difficult to achieve 24 hour-continuous detection. Microminiaturization of the intraocular pressure sensor and wearing it as a contact lens, which is convenient, comfortable and noninvasive, can solve this problem because the soft contact lens with an embedded micro fabricated strain gauge allows the measurement of changes in corneal curvature to correlate to variations of intraocular pressure. We fabricated a strain gauge using micro-electron mechanical systems, and integrated with the contact lens made of polydimethylsiloxane (PDMS) using injection molding. The experimental results showed that the sensitivity was 100. 7 µV/µm. When attached to the corneal surface, the average sensitivity of sensor response of intraocular pressure can be 125.8 µV/mm Hg under the ideal condition.

  8. Relationship between homocysteine and intraocular pressure in men and women

    PubMed Central

    Leibovitzh, Haim; Cohen, Eytan; levi, Amos; Kramer, Michal; Shochat, Tzippy; Goldberg, Elad; Krause, Ilan

    2016-01-01

    Abstract The relationship between homocysteine levels and glaucoma has been questioned in previous studies without conclusive results. In the current study, we assessed the relationship between homocysteine levels and intraocular pressure which is one of the main factors in the development of glaucoma in men and women. A retrospective cross-sectional analysis of a database from a screening center in Israel which assessed 11,850 subjects, within an age range 20 to 80 years. The relationship between homocysteine and intraocular pressure has been investigated by comparing intraocular pressure in subjects with elevated and normal homocysteine and by comparing homocysteine levels in subjects with elevated and normal intraocular pressure. In addition, we compared the levels of homocysteine in subjects with and without a confirmed diagnosis of glaucoma. The mean IOP (±SD) in subjects with normal homocysteine levels(≤15 μmol/L) was 13.2 ± 2.3 mm Hg and 13.4 ± 2.4 mm Hg in those with high homocysteine levels (>15 μmol/L) (P < 0.008, 95% confidence interval [CI] 0.3–0.09).Nonetheless, after multivariate adjustment for age, gender, vitamin B12, and folic acid statistical significance was no longer demonstrated (P = 0.37). Mean homocysteine levels (±SD) in subjects with normal intraocular pressure of ≤ 21 mm Hg was 11.7 ± 5.5 μmol/L and 12.09 ± 3.43 μmol/L in those with elevated intraocular pressure (P = 0.4, 95%CI 1.1–1.8). Mean homocysteine levels (±SD) in subjects with glaucoma were 11.2 ± 3.5 μmol/L compared to 11.7 ± 5.5 μmol/L in subjects without glaucoma and normal intraocular pressure ≤ 21 mm Hg (P = 0.4, 95% CI 1.2–2.1). The current study displays no clinical correlation between the homocysteine level and the intraocular pressure. Homocysteine may not be used as a predictive parameter to recognize those subjects prone to develop elevated intraocular pressure. PMID:27661027

  9. Intra-ocular pressure normalization technique and equipment

    NASA Technical Reports Server (NTRS)

    Baehr, E. F. (Inventor)

    1979-01-01

    A method and apparatus is described for safely reducing abnormally high intraocular pressure in an eye during a predetermined time interval. This allows maintenance of normal intraocular pressure during glaucoma surgery. A pressure regulator of the spring-biassed diaphragm type is provided with additional bias by a column of liquid. The hypodermic needle can be safely inserted into the anterior chamber of the eye. Liquid is then bled out of the column to reduce the bias on the diaphragm of the pressure regulator and, consequently, the output pressure of the regulator. This lowering pressure of the regulator also occurs in the eye by means of a small second bleed path provided between the pressure regulator and the hypodermic needle.

  10. Effect of chymase on intraocular pressure in rabbits.

    PubMed

    Konno, Takashi; Maruichi, Midori; Takai, Shinji; Oku, Hidehiro; Sugiyama, Tetsuya; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Ikeda, Tsunehiko; Miyazaki, Mizuo

    2005-11-01

    Chymase is a chymotrypsin-like serine protease that is stored exclusively in the secretory granules of mast cells and converts big endothelins to endothelin-1 (1-31). The aim of this study was to evaluate the effect of chymase on intraocular pressure in rabbits. Chymase injection (3 and 10 mU) resulted in a trend toward increased intraocular pressure and a significant increase in intraocular pressure at a dose of 10 mU compared with the control. A specific chymase inhibitor, Suc-Val-Pro-Phe(P)(OPh)(2), attenuated the ocular hypertension induced by chymase. Endothelin-1 (1-31) also caused ocular hypertension, which was inhibited by a selective endothelin ET(A) receptor antagonist, cyclo(D-Asp-Pro-D-Val-Leu-D-Trp) (BQ-123). Moreover, chymase-induced ocular hypertension was inhibited by BQ-123. These results suggest that chymase influences the regulation of intraocular pressure, and it is likely that the formation of endothelin-1 (1-31) and subsequent activation of endothelin ET(A) receptors are involved in the development of ocular hypertension induced by chymase.

  11. Blood Pressure Modifies Retinal Susceptibility to Intraocular Pressure Elevation

    PubMed Central

    He, Zheng; Nguyen, Christine T. O.; Armitage, James A.; Vingrys, Algis J.; Bui, Bang V.

    2012-01-01

    Primary open angle glaucoma affects more than 67 million people. Elevated intraocular pressure (IOP) is a risk factor for glaucoma and may reduce nutrient availability by decreasing ocular perfusion pressure (OPP). An interaction between arterial blood pressure and IOP determines OPP; but the exact contribution that these factors have for retinal function is not fully understood. Here we sought to determine how acute modifications of arterial pressure will affect the susceptibility of neuronal function and blood flow to IOP challenge. Anaesthetized (ketamine:xylazine) Long-Evan rats with low (∼60 mmHg, sodium nitroprusside infusion), moderate (∼100 mmHg, saline), or high levels (∼160 mmHg, angiotensin II) of mean arterial pressure (MAP, n = 5–10 per group) were subjected to IOP challenge (10–120 mmHg, 5 mmHg steps every 3 minutes). Electroretinograms were measured at each IOP step to assess bipolar cell (b-wave) and inner retinal function (scotopic threshold response or STR). Ocular blood flow was measured using laser-Doppler flowmetry in groups with similar MAP level and the same IOP challenge protocol. Both b-wave and STR amplitudes decreased with IOP elevation. Retinal function was less susceptible to IOP challenge when MAP was high, whereas the converse was true for low MAP. Consistent with the effects on retinal function, higher IOP was needed to attenuated ocular blood flow in animals with higher MAP. The susceptibility of retinal function to IOP challenge can be ameliorated by acute high BP, and exacerbated by low BP. This is partially mediated by modifications in ocular blood flow. PMID:22359566

  12. An ultralow power wireless intraocular pressure monitoring system

    NASA Astrophysics Data System (ADS)

    Demeng, Liu; Niansong, Mei; Zhaofeng, Zhang

    2014-10-01

    This paper describes an ultralow power wireless intraocular pressure (IOP) monitoring system that is dedicated to sensing and transferring intraocular pressure of glaucoma patients. Our system is comprised of a capacitive pressure sensor, an application-specific integrated circuit, which is designed on the SMIC 180 nm process, and a dipole antenna. The system is wirelessly powered and demonstrates a power consumption of 7.56 μW at 1.24 V during continuous monitoring, a significant reduction in active power dissipation compared to existing work. The input RF sensitivity is -13 dBm. A significant reduction in input RF sensitivity results from the reduction of mismatch time of the ASK modulation caused by FM0 encoding. The system exhibits an average error of ± 1.5 mmHg in measured pressure. Finally, a complete IOP system is demonstrated in the real biological environment, showing a successful reading of the pressure of an eye.

  13. Real-time, whole-brain, temporally resolved pressure responses in translational head impact.

    PubMed

    Zhao, Wei; Ji, Songbai

    2016-02-01

    Theoretical debate still exists on the role of linear acceleration ( a lin) on the risk of brain injury. Recent injury metrics only consider head rotational acceleration ( a rot) but not a lin, despite that real-world on-field head impacts suggesting a lin significantly improves a concussion risk function. These controversial findings suggest a practical challenge in integrating theory and real-world experiment. Focusing on tissue-level mechanical responses estimated from finite-element (FE) models of the human head, rather than impact kinematics alone, may help address this debate. However, the substantial computational cost incurred (runtime and hardware) poses a significant barrier for their practical use. In this study, we established a real-time technique to estimate whole-brain a lin-induced pressures. Three hydrostatic atlas pressures corresponding to translational impacts (referred to as 'brain print') along the three major axes were pre-computed. For an arbitrary a lin profile at any instance in time, the atlas pressures were linearly scaled and then superimposed to estimate whole-brain responses. Using 12 publically available, independently measured or reconstructed real-world a lin profiles representative of a range of impact/injury scenarios, the technique was successfully validated (except for one case with an extremely short impulse of approx. 1 ms). The computational cost to estimate whole-brain pressure responses for an entire a lin profile was less than 0.1 s on a laptop versus typically hours on a high-end multicore computer. These findings suggest the potential of the simple, yet effective technique to enable future studies to focus on tissue-level brain responses, rather than solely relying on global head impact kinematics that have plagued early and contemporary brain injury research to date.

  14. [Problems of intraocular pressure in scuba diving (author's transl)].

    PubMed

    Kalthoff, H; John, S; Scholz, V

    1975-04-01

    The reactions of intraocular pressure (i. o. p.), pulse rate, and blood pressure were studied on 30 scuba divers in a pressure tank. Under excess pressures of 2 and 4 atm the i.o.p. showed an average fall of 2-3 mm Hg. The pulse rate fell in average by 4-5/min, while the blood pressure only showed minor changes. In the authors' opinion a well compensated chronic simple glaucoma with intact discs and fields does not exclude fitness for scuba diving.

  15. Payload and Components Real-Time Automated Test System (PACRATS), Data Acquisition of Leak Rate and Pressure Data Test Procedure

    NASA Technical Reports Server (NTRS)

    Rinehart, Maegan L.

    2011-01-01

    The purpose of this activity is to provide the Mechanical Components Test Facility (MCTF) with the capability to obtain electronic leak test and proof pressure data, Payload and Components Real-time Automated Test System (PACRATS) data acquisition software will be utilized to display real-time data. It will record leak rates and pressure/vacuum level(s) simultaneously. This added functionality will provide electronic leak test and pressure data at specified sampling frequencies. Electronically stored data will provide ES61 with increased data security, analysis, and accuracy. The tasks performed in this procedure are to verify PACRATS only, and are not intended to provide verifications for MCTF equipment.

  16. The interaction between intracranial pressure, intraocular pressure and lamina cribrosal compression in glaucoma.

    PubMed

    McMonnies, Charles W

    2016-05-01

    This review examines some of the biomechanical consequences associated with the opposing intraocular and intracranial forces. These forces compress the lamina cribrosa and are a potential source of glaucomatous pathology. A difference between them creates a displacement force on the lamina cribrosa. Increasing intraocular pressure and/or decreasing intracranial pressure will increase the trans-lamina cribrosa pressure difference and the risk of its posterior displacement, canal expansion and the formation of pathological cupping. Both intraocular pressure and intracranial pressure can be elevated during a Valsalva manoeuvre with associated increases in both anterior and posterior lamina cribrosa loading as well as its compression. Any resulting thinning of or damage to the lamina cribrosa and/or retinal ganglion cell axons and/or astrocyte and glial cells attached to the matrix of the lamina cribrosa and/or reduction in blood flow to the lamina cribrosa may contribute to glaucomatous neuropathy. Thinning of the lamina cribrosa reduces its stiffness and increases the risk of its posterior displacement. Optic nerve head posterior displacement warrants medical or surgical lowering of intraocular pressure; however, compared to intraocular pressure, the trans-lamina cribrosa pressure difference may be more important in pressure-related pathology of the optic nerve head region. Similarly important could be increased compression loading of the lamina cribrosa. Reducing participation in activities which elevate intraocular and intracranial pressure will decrease lamina cribrosa compression exposure and may contribute to glaucoma management and may have prognostic significance for glaucoma suspects. PMID:27079432

  17. Effects of angiotensin, vasopressin and atrial natriuretic peptide on intraocular pressure in anesthetized rats

    NASA Technical Reports Server (NTRS)

    Palm, D. E.; Shue, S. G.; Keil, L. C.; Balaban, C. D.; Severs, W. B.

    1995-01-01

    The effects of atrial natriuretic peptide (ANP), vasopressin (AVP) and angiotensin (ANG) on blood and intraocular pressures of pentobarbital anesthetized rats were evaluated following intravenous, intracerebroventricular or anterior chamber routes of administration. Central injections did not affect intraocular pressure. Equipressor intravenous infusions of ANG raised, whereas AVP decreased, intraocular pressure. Direct infusions of a balanced salt solution (0.175 microliter/min) raised intraocular pressure between 30 and 60 min. Adding ANG or ANP slightly reduced this solvent effect but AVP was markedly inhibitory. An AVP-V1 receptor antagonist reversed the blunting of the solvent-induced rise by the peptide, indicating receptor specificity. Acetazolamide pretreatment lowered intraocular pressure, but the solvent-induced rise in intraocular pressure and inhibition by AVP still occurred without altering the temporal pattern. Thus, these effects appear unrelated to aqueous humor synthesis rate. The data support the possibility of intraocular pressure regulation by peptides acting from the blood and aqueous humor.

  18. Intra-ocular pressure normalization technique and equipment

    NASA Technical Reports Server (NTRS)

    Mcgannon, W. J. (Inventor)

    1980-01-01

    A method and apparatus for safely reducing abnormally high intraocular pressure in an eye during a predetermined time interval is presented. This allows maintenance of normal intraocular pressure during glaucoma surgery. According to the invention, a pressure regulator of the spring biased diaphragm type is provided with additional bias by a column of liquid. The height of the column of liquid is selected such that the pressure at a hypodermic needle connected to the output of the pressure regulator is equal to the measured pressure of the eye. The hypodermic needle can then be safely inserted into the anterior chamber of the eye. Liquid is then bled out of the column to reduce the bias on the diaphragm of the pressure regulator and, consequently, the output pressure of the regulator. This lowering pressure of the regulator also occurs in the eye by means of a small second bleed path provided between the pressure regulator and the hypodermic needle. Alternately, a second hypodermic needle may be inserted into the eye to provide a controlled leak off path for excessive pressure and clouded fluid from the anterior chamber.

  19. Real-time pressure monitoring for dynamic control during paper mill operation using fiber optic pressure sensors

    NASA Astrophysics Data System (ADS)

    Fielder, Robert S.; Boyd, Clark; Palmer, Matthew; Eriksen, Oddbjørn

    2006-03-01

    Fiber optic pressure sensors were integrated into the grinding plates of an operational paper pulp mill for real-time monitoring of the pulp grinding process. On-line system monitoring will allow smart, active control of the grinding plates thereby improving the quality and consistency of the pulp produced. Sensors were constructed and calibrated for use in the harsh environment of an operating paper pulp grinder. The sensors were 1.65mm in diameter including titanium housing, and were installed directly into the grooves of the grinding plates. The sensing elements were flush-mounted with the wall and exposed to the wood pulp slurry. Nine sensors were calibrated up to 1000psi. During operation, pressure was sampled at 1.0MHz, and pressure spikes up to 175psi were observed. Pressure pulses measured are due to the relative motion between the grooves and channels on two pulp grinding plates. The consistency, size distribution, and quality of paper pulp exiting from the grinder are directly related to the distance between the channels on the two rotating elements. The pressure pulses produced are also proportional to the distance between channels. Therefore, by monitoring pressure fluctuations, grinding elements can be dynamically controlled thereby producing a "smart mill."

  20. Real-Time Optical Monitoring of Flow Kinetics and Gas Phase Reactions Under High-Pressure OMCVD Conditions

    NASA Technical Reports Server (NTRS)

    Dietz, N.; McCall, S.; Bachmann, K. J.

    2001-01-01

    This contribution addresses the real-time optical characterization of gas flow and gas phase reactions as they play a crucial role for chemical vapor phase depositions utilizing elevated and high pressure chemical vapor deposition (HPCVD) conditions. The objectives of these experiments are to validate on the basis of results on real-time optical diagnostics process models simulation codes, and provide input parameter sets needed for analysis and control of chemical vapor deposition at elevated pressures. Access to microgravity is required to retain high pressure conditions of laminar flow, which is essential for successful acquisition and interpretation of the optical data. In this contribution, we describe the design and construction of the HPCVD system, which include access ports for various optical methods of real-time process monitoring and to analyze the initial stages of heteroepitaxy and steady-state growth in the different pressure ranges. To analyze the onset of turbulence, provisions are made for implementation of experimental methods for in-situ characterization of the nature of flow. This knowledge will be the basis for the design definition of experiments under microgravity, where gas flow conditions, gas phase and surface chemistry, might be analyzed by remote controlled real-time diagnostics tools, developed in this research project.

  1. The effect of intraocular gas and fluid volumes on intraocular pressure.

    PubMed

    Simone, J N; Whitacre, M M

    1990-02-01

    Large increases in the intraocular pressure (IOP) of postoperative gas-containing eyes may require the removal of gas or fluid to reduce the IOP to the normal range. Application of the ideal gas law to Friedenwald's equation provides a mathematical model of the relationship between IOP, intraocular gas and fluid volumes, and the coefficient of scleral rigidity. This mathematic model shows that removal of a given volume of gas or fluid produces an identical decrease in IOP and that the more gas an eye contains, the greater the volume reduction necessary to reduce the pressure. Application of the model shows that the effective coefficient of scleral rigidity is low (mean K, 0.0021) in eyes with elevated IOP that have undergone vitrectomy and retinal cryopexy and very low (mean K, 0.0013) in eyes with elevated IOP that have undergone placement of a scleral buckle and band. By using the appropriate mean coefficient of rigidity, the volume of material to be aspirated to produce a given decrease in IOP can be predicted with clinically useful accuracy. PMID:2326014

  2. [Intraocular pressure in snorkling and diving (author's transl)].

    PubMed

    Kalthoff, H; John, S

    1976-02-01

    The reactions of the intraocular pressure (i.o.p) in snorkling and scuba diving were studies on 29 healthy subjects. A patient with chronic glaucoma simplex was examined in a pressure tank. The results confirm the author's opinion, that a well compensated chronic glaucoma simplex with intact discs and fields does not exclude fitness to dive. However, a diver with narrow angel glaucoma risks sudden rise in i.o.p. and acute glaucoma while ascending to the surface. Persons, who are examined for fitness to dive, should be seen by an ophthalmologist, if they have a glaucoma or if they are hypermetropic and over 40 years of age.

  3. Note: A micro-perfusion system for use during real-time physiological studies under high pressure.

    PubMed

    Maltas, Jeff; Long, Zac; Huff, Alison; Maloney, Ryan; Ryan, Jordan; Urayama, Paul

    2014-10-01

    We construct a micro-perfusion system using piston screw pump generators for use during real-time, high-pressure physiological studies. Perfusion is achieved using two generators, with one generator being compressed while the other is retracted, thus maintaining pressurization while producing fluid flow. We demonstrate control over perfusion rates in the 10-μl/s range and the ability to change between fluid reservoirs at up to 50 MPa. We validate the screw-pump approach by monitoring the cyanide-induced response of UV-excited autofluorescence from Saccharomyces cerevisiae under pressurization.

  4. 3D Real-Time Echocardiography Combined with Mini Pressure Wire Generate Reliable Pressure-Volume Loops in Small Hearts

    PubMed Central

    Linden, Katharina; Dewald, Oliver; Gatzweiler, Eva; Seehase, Matthias; Duerr, Georg Daniel; Dörner, Jonas; Kleppe, Stephanie

    2016-01-01

    Background Pressure-volume loops (PVL) provide vital information regarding ventricular performance and pathophysiology in cardiac disease. Unfortunately, acquisition of PVL by conductance technology is not feasible in neonates and small children due to the available human catheter size and resulting invasiveness. The aim of the study was to validate the accuracy of PVL in small hearts using volume data obtained by real-time three-dimensional echocardiography (3DE) and simultaneously acquired pressure data. Methods In 17 piglets (weight range: 3.6–8.0 kg) left ventricular PVL were generated by 3DE and simultaneous recordings of ventricular pressure using a mini pressure wire (PVL3D). PVL3D were compared to conductance catheter measurements (PVLCond) under various hemodynamic conditions (baseline, alpha-adrenergic stimulation with phenylephrine, beta-adrenoreceptor-blockage using esmolol). In order to validate the accuracy of 3D volumetric data, cardiac magnetic resonance imaging (CMR) was performed in another 8 piglets. Results Correlation between CMR- and 3DE-derived volumes was good (enddiastolic volume: mean bias -0.03ml ±1.34ml). Computation of PVL3D in small hearts was feasible and comparable to results obtained by conductance technology. Bland-Altman analysis showed a low bias between PVL3D and PVLCond. Systolic and diastolic parameters were closely associated (Intraclass-Correlation Coefficient for: systolic myocardial elastance 0.95, arterial elastance 0.93, diastolic relaxation constant tau 0.90, indexed end-diastolic volume 0.98). Hemodynamic changes under different conditions were well detected by both methods (ICC 0.82 to 0.98). Inter- and intra-observer coefficients of variation were below 5% for all parameters. Conclusions PVL3D generated from 3DE combined with mini pressure wire represent a novel, feasible and reliable method to assess different hemodynamic conditions of cardiac function in hearts comparable to neonate and infant size. This

  5. Tear Film Functions and Intraocular Pressure Changes in Pregnancy.

    PubMed

    Ibraheem, Waheed A; Ibraheem, Anifat B; Tjani, Aramide M; Oladejo, Samuel; Adepoju, Susan; Folohunso, Bukola

    2015-12-01

    Pregnancy related ocular changes are diverse with varied clinical outcome. In a cross-sectional, descriptive case control study, we evaluated tear film functions and intraocular pressure during pregnancy and compared the results with non-pregnant women. A total of 270 participants including 165 healthy pregnant women and 105 non-pregnant who were free from systemic and pre-pregnancy eye diseases were investigated. Snellen's chart, fluorescein dye, No 41 Whatman filter paper, Perkin's tonometer were employed to assess visual acuity, tear break up time (TBUT), Schirmer's test (ST), intraocular pressure (IOP) on all subjects. The mean values for IOP (mmHg), TBUT (seconds) and Schirmer's reading (mm) were: 13.24 ± 2.18, 25.05 ± 9.30, 37.03 ± 17.06 and 14.24 ± 2.66, 22.10 ± 10.81, 50.13 ± 19.10 for cases and controls respectively. Schirmer's reading (SR) was significantly lower among pregnant women. Only age had a statistically significant association with the measured parameters. Our study revealed reduced SR during pregnancy. We suggest routine ocular assessment for pregnant women to forestall deleterious sequelae of dry eye.

  6. Extensive facial and orbital infantile hemangiomas associated with high intraocular pressure.

    PubMed

    Shatriah, Ismail; Norazizah, Mohd-Amin; Wan-Hitam, Wan-Hazabbah; Wong, Abd-Rahim; Yunus, Rohaizan; Leo, Seo-Wei

    2013-01-01

    High intraocular pressure is a rare ophthalmic condition associated with infantile hemangiomas that involves the orbit, eyelid, or both. Here, we describe a patient with extensive facial and orbital infantile hemangiomas associated with high intraocular pressure in the affected eye. The prompt management of this challenging condition is essential. PMID:22329437

  7. Associations with Intraocular Pressure in a Large Cohort

    PubMed Central

    Chan, Michelle P.Y.; Grossi, Carlota M.; Khawaja, Anthony P.; Yip, Jennifer L.Y.; Khaw, Kay-Tee; Patel, Praveen J.; Khaw, Peng T.; Morgan, James E.; Vernon, Stephen A.; Foster, Paul J.

    2016-01-01

    Purpose To describe the associations of physical and demographic factors with Goldmann-correlated intraocular pressure (IOPg) and corneal-compensated intraocular pressure (IOPcc) in a British cohort. Design Cross-sectional study within the UK Biobank, a large-scale multisite cohort study in the United Kingdom. Participants We included 110 573 participants from the UK Biobank with intraocular pressure (IOP) measurements available. Their mean age was 57 years (range, 40–69 years); 54% were women, and 90% were white. Methods Participants had 1 IOP measurement made on each eye using the Ocular Response Analyzer noncontact tonometer. Linear regression models were used to assess the associations of IOP with physical and demographic factors. Main Outcome Measures The IOPg and IOPcc. Results The mean IOPg was 15.72 mmHg (95% confidence interval [CI], 15.70–15.74 mmHg), and the mean IOPcc was 15.95 mmHg (15.92–15.97 mmHg). After adjusting for covariates, IOPg and IOPcc were both significantly associated with older age, male sex, higher systolic blood pressure (SBP), faster heart rate, greater myopia, self-reported glaucoma, and colder season (all P < 0.001). The strongest determinants of both IOPg and IOPcc were SBP (partial R2: IOPg 2.30%, IOPcc 2.26%), followed by refractive error (IOPg 0.60%, IOPcc 1.04%). The following variables had different directions of association with IOPg and IOPcc: height (−0.77 mmHg/m IOPg; 1.03 mmHg/m IOPcc), smoking (0.19 mmHg IOPg, −0.35 mmHg IOPcc), self-reported diabetes (0.41 mmHg IOPg, −0.05 mmHg IOPcc), and black ethnicity (−0.80 mmHg IOPg, 0.77 mmHg IOPcc). This suggests that height, smoking, diabetes, and ethnicity are related to corneal biomechanical properties. The increase in both IOPg and IOPcc with age was greatest among those of mixed ethnicities, followed by blacks and whites. The same set of covariates explained 7.4% of the variability of IOPcc but only 5.3% of the variability of IOPg. Conclusions This analysis

  8. Change in Intraocular Pressure During Point-of-Care Ultrasound

    PubMed Central

    Berg, Cameron; Doniger, Stephanie J.; Zaia, Brita; Williams, Sarah R.

    2015-01-01

    Introduction Point-of-care ocular ultrasound (US) is a valuable tool for the evaluation of traumatic ocular injuries. Conventionally, any maneuver that may increase intraocular pressure (IOP) is relatively contraindicated in the setting of globe rupture. Some authors have cautioned against the use of US in these scenarios because of a theoretical concern that an US examination may cause or exacerbate the extrusion of intraocular contents. This study set out to investigate whether ocular US affects IOP. The secondary objective was to validate the intraocular pressure measurements obtained with the Diaton® as compared with standard applanation techniques (the Tono-Pen®). Methods We enrolled a convenience sample of healthy adult volunteers. We obtained the baseline IOP for each patient by using a transpalpebral tonometer. Ocular US was then performed on each subject using a high-frequency linear array transducer, and a second IOP was obtained during the US examination. A third IOP measurement was obtained following the completion of the US examination. To validate transpalpebral measurement, a subset of subjects also underwent traditional transcorneal applanation tonometry prior to the US examination as a baseline measurement. In a subset of 10 patients, we obtained baseline pre-ultrasound IOP measurements with the Diaton® and Tono-Pen®, and then compared them. Results The study included 40 subjects. IOP values during ocular US examination were slightly greater than baseline (average +1.8mmHg, p=0.01). Post-US examination IOP values were not significantly different than baseline (average −0.15mmHg, p=0.42). In a subset of 10 subjects, IOP values were not significantly different between transpalpebral and transcorneal tonometry (average +0.03mmHg, p=0.07). Conclusion In healthy volunteer subjects, point-of-care ocular US causes a small and transient increase in IOP. We also showed no difference between the Diaton® and Tono-Pen® methods of IOP measurement

  9. Sustained elevation in intraocular pressure associated with intravitreal bevacizumab injections.

    PubMed

    Kahook, Malik Y; Kimura, Alan E; Wong, Lisa J; Ammar, David A; Maycotte, Marco A; Mandava, Naresh

    2009-01-01

    This retrospective case series reports sustained elevation of intraocular pressure (IOP) after single or repeated intravitreal injections of bevacizumab (Avastin; Genentech, San Francisco, CA) for wet age-related macular degeneration (AMD). All six cases experienced significant and sustained elevation in IOP after single or repeated intravitreal injections of bevacizumab. Initiation or advancement of IOP-lowering therapy was required in all cases. The results support the need for further studies investigating the incidence of this potential side effect and the need for close long-term surveillance of IOP after injection of bevacizumab, particularly in patients with glaucoma or suspected glaucoma. Future in vitro and in vivo studies are needed to better understand the reasons for this observed phenomenon. PMID:19485295

  10. Persistently raised intraocular pressure following extracapsular cataract extraction.

    PubMed

    David, R; Tessler, Z; Yagev, R; Briscoe, D; Biedner, B Z; Gilad, E; Yassur, Y

    1990-05-01

    In this population based study we have reviewed the files of all patients who underwent an extracapsular cataract extraction (ECCE) between 1984 and 1987, were normotensives prior to surgery, and were followed up for at least 10 months after the ECCE. From a total of 1047 operations 746 qualified for the inclusion criteria; of these, 16 (2.1%) were found to have a consistently raised intraocular pressure (greater than 21 mmHg) on more than two occasions) at four months or later after surgery and throughout at least a six-month period. An increased incidence of secondary aphakic glaucoma was associated with anterior chamber IOL implantation (p less than 0.001) and posterior capsule rupture (p less than 0.01), but not with any of the other variables examined (age, sex, surgeon).

  11. Real-time measurement of blood pressure with Nexfin in a patient with thalidomide-related phocomelia.

    PubMed

    Earle, Rosie; Vaghadia, Himat; Shanahan, Enda; Tang, Raymond; Sawka, Andrew

    2016-11-01

    We report the novel application of photoplethysmographic technology with the Nexfin HD monitor for real-time measurement of blood pressure (BP) in a patient with tetraamelia. The patient was a 58-year-old man with tetraamelia secondary to thalidomide exposure in utero, who presented for surgical excision of a maxillary schwannoma. Because difficulty of cuff use on rudimentary limbs and failure to gain invasive arterial access due to abnormalities of limb vasculature, this population is known to pose some unique challenges for BP measurement. Nexfin may offer an alternative noninvasive method to detect BP in patients with phocomelia during the perioperative period. PMID:27687383

  12. A new device to noninvasively estimate the intraocular pressure produced during ocular compression

    PubMed Central

    Korenfeld, Michael S; Dueker, David K

    2016-01-01

    Purpose To describe a noninvasive instrument that estimates intraocular pressure during episodes of external globe compression and to demonstrate the accuracy and reliability of this device by comparing it to the intraocular pressures simultaneously and manometrically measured in cannulated eyes. Methods A thin fluid-filled bladder was constructed from flexible and inelastic plastic sheeting and was connected to a pressure transducer with high pressure tubing. The output of the pressure transducer was sent to an amplifier and recorded. This device was validated by measuring induced pressure in the fluid-filled bladder while digital pressure was applied to one surface, and the other surface was placed directly against a human cadaver eye or in vivo pig eye. The human cadaver and in vivo pig eyes were each cannulated to provide a manometric intraocular pressure control. Results The measurements obtained with the newly described device were within ~5% of simultaneously measured manometric intraocular pressures in both a human cadaver and in vivo pig eye model for a pressure range of ~15–100 mmHg. Conclusion This novel noninvasive device is useful for estimating the intraocular pressure transients induced during any form of external globe compression; this is a clinical setting where no other devices can be used to estimate intraocular pressure. PMID:26955260

  13. Real-time combustion control and diagnostics sensor-pressure oscillation monitor

    DOEpatents

    Chorpening, Benjamin T.; Thornton, Jimmy; Huckaby, E. David; Richards, George A.

    2009-07-14

    An apparatus and method for monitoring and controlling the combustion process in a combustion system to determine the amplitude and/or frequencies of dynamic pressure oscillations during combustion. An electrode in communication with the combustion system senses hydrocarbon ions and/or electrons produced by the combustion process and calibration apparatus calibrates the relationship between the standard deviation of the current in the electrode and the amplitudes of the dynamic pressure oscillations by applying a substantially constant voltage between the electrode and ground resulting in a current in the electrode and by varying one or more of (1) the flow rate of the fuel, (2) the flow rate of the oxidant, (3) the equivalence ratio, (4) the acoustic tuning of the combustion system, and (5) the fuel distribution in the combustion chamber such that the amplitudes of the dynamic pressure oscillations in the combustion chamber are calculated as a function of the standard deviation of the electrode current. Thereafter, the supply of fuel and/or oxidant is varied to modify the dynamic pressure oscillations.

  14. Intraocular Pressure Regulation: Findings of Pulse-Dependent Trabecular Meshwork Motion Lead to Unifying Concepts of Intraocular Pressure Homeostasis

    PubMed Central

    2014-01-01

    Abstract Intraocular pressure (IOP) is the only treatable risk factor in glaucoma, one of the world's leading causes of blindness. Mechanisms that maintain IOP within a normal range have been poorly understood in contrast to intrinsic mechanisms that regulate systemic blood pressure. Vessel walls experience continuous pulse-induced cyclic pressure and flow. Pressure-dependent wall stress and flow-dependent shear stress provide sensory signals that initiate mechanotransduction responses. The responses optimize vessel wall elasticity, compliance and lumen size, providing a feedback loop to maintain intrinsic pressure homeostasis. Aqueous humor is part of a vascular circulatory loop, being secreted into the anterior chamber of the eye from the vasculature, then returning to the vasculature by passing through the trabecular meshwork (TM), a uniquely modified vessel wall interposed between the anterior chamber and a vascular sinus called Schlemm's canal (SC). Since pressure in circulatory loops elsewhere is modulated by cyclic stresses, one might predict similar pressure modulation in the aqueous outflow system. Recent laboratory evidence in fact demonstrates that cyclic IOP changes alter aqueous outflow while increasing cellularity and contractility of TM cells. Cyclic changes also lead to alterations in gene expression, changes in cytoskeletal networks and modulation of signal transduction. A new technology, phase-based optical coherence tomography, demonstrates in vivo pulse-dependent TM motion like that elsewhere in the vasculature. Recognition of pulse-dependent TM motion provides a linkage to well-characterized mechanisms that provide pressure homeostasis in the systemic vasculature. The linkage may permit unifying concepts of pressure control and provide new insights into IOP homeostatic mechanisms. PMID:24359130

  15. Effects of phacoemulsification on intraocular pressure and anterior chamber depth

    PubMed Central

    LIU, XIN-QUAN; ZHU, HUA-YING; SU, JING; HAO, XIAO-JUN

    2013-01-01

    The aim of this study was to investigate the effects of phacoemulsification with intraocular lens (IOL) implantation on intraocular pressure (IOP) and anterior chamber depth (ACD) in patients with cataract or cataract associated with primary angle closure (PAC). A total of 361 patients (481 affected eyes) with senile cataract (cataract group) and 44 patients (52 affected eyes) with cataract associated with PAC (cataract with PAC group) underwent phacoemulsification with IOL implantation from July 2005 to May 2007 and were followed up for 3 to 25 months. There was a significant difference between pre-operative and post-operative IOPs (t=9.270, P<0.01) in the cataract group and in the cataract with PAC group (t=3.29, P<0.01). No significant differences were identified in pre-operative IOP (t=−2.437, P>0.05) and the IOP three months after surgery (t=2.154, P>0.05) between the two groups. There was a significant difference between the pre-operative and post-operative ACDs (t=7.781, P<0.01) in the cataract group and in the cataract with PAC group (t=4.528, P<0.01). A significant difference in ACD between the two groups (t=8.325, P<0.01) existed prior to surgery but following surgery, the ACDs of the two groups were not significantly different (t=2.86, P>0.05). Phacoemulsification with IOL implantation has IOP-lowering effects on cataract and cataract with PAC patients. The International Society of Geography and Epidemiology of Ophthalmology classification method for angle closure glaucoma was adopted in our study. Furhter studies are required to prove the safety and mechanism of lowering IOP impact of phacoemulsifation towards PAC glaucoma (PACG). PMID:23403825

  16. Effects of phacoemulsification on intraocular pressure and anterior chamber depth.

    PubMed

    Liu, Xin-Quan; Zhu, Hua-Ying; Su, Jing; Hao, Xiao-Jun

    2013-02-01

    The aim of this study was to investigate the effects of phacoemulsification with intraocular lens (IOL) implantation on intraocular pressure (IOP) and anterior chamber depth (ACD) in patients with cataract or cataract associated with primary angle closure (PAC). A total of 361 patients (481 affected eyes) with senile cataract (cataract group) and 44 patients (52 affected eyes) with cataract associated with PAC (cataract with PAC group) underwent phacoemulsification with IOL implantation from July 2005 to May 2007 and were followed up for 3 to 25 months. There was a significant difference between pre-operative and post-operative IOPs (t=9.270, P<0.01) in the cataract group and in the cataract with PAC group (t=3.29, P<0.01). No significant differences were identified in pre-operative IOP (t=-2.437, P>0.05) and the IOP three months after surgery (t=2.154, P>0.05) between the two groups. There was a significant difference between the pre-operative and post-operative ACDs (t=7.781, P<0.01) in the cataract group and in the cataract with PAC group (t=4.528, P<0.01). A significant difference in ACD between the two groups (t=8.325, P<0.01) existed prior to surgery but following surgery, the ACDs of the two groups were not significantly different (t=2.86, P>0.05). Phacoemulsification with IOL implantation has IOP-lowering effects on cataract and cataract with PAC patients. The International Society of Geography and Epidemiology of Ophthalmology classification method for angle closure glaucoma was adopted in our study. Furhter studies are required to prove the safety and mechanism of lowering IOP impact of phacoemulsifation towards PAC glaucoma (PACG).

  17. An examination of the hypothesis that intraocular pressure elevation episodes can have prognostic significance in glaucoma suspects.

    PubMed

    McMonnies, Charles

    2015-01-01

    The efficacy of intraocular pressure reduction in retarding the progression of glaucoma has been demonstrated. This review examines the potential for prognostic advantage for glaucoma suspects in reducing their optic nerve head exposure to elevated intraocular pressure associated with activities which have been shown to elevate intraocular pressure. In this observational study, patients examined at the Centre for Eye Health (University of New South Wales) with a diagnosis of glaucoma suspect were surveyed to determine their histories for participation in activities which are known to elevate intraocular pressure. The evidence regarding the pathological significance of these sources of elevation in susceptible patients was examined. Apart from the universality of sleep-related intraocular pressure elevations, the histories from 183 confirmed glaucoma suspects indicate a wide range and variation in frequency of participation in other intraocular pressure elevating activities. A reduction in exposure to elevated intraocular pressure may improve the prognosis for glaucoma suspects. Additional patient specific assessment of the results of this screening could provide an indication of the degree (frequency, intensity level and duration) of exposure to elevated intraocular pressure. Such information may provide the basis for improving a patient's prognosis by helping them to identify opportunities to reduce such exposure to elevated intraocular pressure. Any benefit of reduction of such exposure appears likely to be greater if activities which elevate intraocular pressure are of long duration, occur frequently, occur over a long period of time, and/or involve high levels of intraocular pressure elevation.

  18. An examination of the hypothesis that intraocular pressure elevation episodes can have prognostic significance in glaucoma suspects

    PubMed Central

    McMonnies, Charles

    2014-01-01

    The efficacy of intraocular pressure reduction in retarding the progression of glaucoma has been demonstrated. This review examines the potential for prognostic advantage for glaucoma suspects in reducing their optic nerve head exposure to elevated intraocular pressure associated with activities which have been shown to elevate intraocular pressure. In this observational study, patients examined at the Centre for Eye Health (University of New South Wales) with a diagnosis of glaucoma suspect were surveyed to determine their histories for participation in activities which are known to elevate intraocular pressure. The evidence regarding the pathological significance of these sources of elevation in susceptible patients was examined. Apart from the universality of sleep-related intraocular pressure elevations, the histories from 183 confirmed glaucoma suspects indicate a wide range and variation in frequency of participation in other intraocular pressure elevating activities. A reduction in exposure to elevated intraocular pressure may improve the prognosis for glaucoma suspects. Additional patient specific assessment of the results of this screening could provide an indication of the degree (frequency, intensity level and duration) of exposure to elevated intraocular pressure. Such information may provide the basis for improving a patient's prognosis by helping them to identify opportunities to reduce such exposure to elevated intraocular pressure. Any benefit of reduction of such exposure appears likely to be greater if activities which elevate intraocular pressure are of long duration, occur frequently, occur over a long period of time, and/or involve high levels of intraocular pressure elevation. PMID:25199440

  19. The influence of intraocular pressure and air jet pressure on corneal contactless tonometry tests.

    PubMed

    Simonini, Irene; Pandolfi, Anna

    2016-05-01

    The air puff is a dynamic contactless tonometer test used in ophthalmology clinical practice to assess the biomechanical properties of the human cornea and the intraocular pressure due to the filling fluids of the eye. The test is controversial, since the dynamic response of the cornea is governed by the interaction of several factors which cannot be discerned within a single measurement. In this study we describe a numerical model of the air puff tests, and perform a parametric analysis on the major action parameters (jet pressure and intraocular pressure) to assess their relevance on the mechanical response of a patient-specific cornea. The particular cornea considered here has been treated with laser reprofiling to correct myopia, and the parametric study has been conducted on both the preoperative and postoperative geometries. The material properties of the cornea have been obtained by means of an identification procedure that compares the static biomechanical response of preoperative and postoperative corneas under the physiological IOP. The parametric study on the intraocular pressure suggests that the displacement of the cornea׳s apex can be a reliable indicator for tonometry, and the one on the air jet pressure predicts the outcomes of two or more distinct measurements on the same cornea, which can be used in inverse procedures to estimate the material properties of the tissue.

  20. Real-time flavor release from French fries using atmospheric pressure chemical ionization-mass spectrometry.

    PubMed

    van Loon, Wil A M; Linssen, Jozef P H; Boelrijk, Alexandra E M; Burgering, Maurits J M; Voragen, Alphons G J

    2005-08-10

    Flavor release from French fries was measured with atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) using both assessors (in vivo) and a mouth model system (in vitro). Several volatiles measured with APCI were identified with MS-MS. The effect of frying time, salt addition, and an alternative process using superheated steam was determined on I(max) (maximum intensity of compounds) and on t(max) (time of maximum intensity). In vitro a "chewing" frequency of 0.60 Hz caused an increased t(max) for low molecular weight compounds compared to the other frequencies tested. Above 0.93 Hz further increase in the frequency did not affect t(max). Trends observed with in vivo experiments could be verified with in vitro experiments. I(max) correlated well with frying time. Addition of salt resulted in a decreased t(max), suggesting a salting-out effect. The alternative process caused a layer of oil on the surface, and this resulted in a higher t(max), but no effect on I(max) was found. This phenomenon may be critical for the sensory quality and would not have been observed with static volatile measurements, demonstrating the value of flavor release measurements.

  1. Pharmacotherapy of intraocular pressure: part I. Parasympathomimetic, sympathomimetic and sympatholytics.

    PubMed

    Costagliola, Ciro; dell'Omo, Roberto; Romano, Mario R; Rinaldi, Michele; Zeppa, Lucia; Parmeggiani, Francesco

    2009-11-01

    Elevated intraocular pressure (IOP) has been recognized as the major risk factor for the development of glaucoma and a wide range of options are now available to reduce it: medical treatment, laser, filtering, or cyclodestructive surgery (alone or in combination). All these modalities act by decreasing eye pressure and, thereby, protecting the optic nerve head from a mechanic direct and/or vascular indirect insult. Topical medical therapy represents the first-choice treatment and, in most cases, it effectively controls IOP, avoiding the occurrence of further optic nerve damage. All medications lower IOP in two main ways: decreasing the production of aqueous humour or by increasing its outflow from the eye. Consequently, antiglaucoma drugs either suppress aqueous humour formation (beta-adrenergic antagonists, carbonic anhydrase inhibitors, and alpha-2-adrenergic agonists) or raise aqueous humour outflow throughout the conventional (e.g., pilocarpine) or uveoscleral (prostaglandin FP receptor agonists, and prostamides) route. In addition, fixed and unfixed combinations of antiglaucoma compounds have also been available for patients requiring more than one type of medication. This review, which is part one of two (please see Expert Opinion on Pharmacotherapy 10 (17)) briefly considers the characteristics of sympathomimetic, sympatholytics and parasympathomimetic commonly employed in the medical treatment of glaucoma, mainly the primary open-angle form, focusing the discussion on the clinical evidence supporting the use of these three classes of compound. PMID:19874249

  2. Rapid detection of Salmonella from hydrodynamic pressure-treated poultry using molecular beacon real-time PCR.

    PubMed

    Patel, J R; Bhagwat, A A; Sanglay, G C; Solomon, M B

    2006-02-01

    A real-time polymerase chain reaction (PCR) assay was evaluated to detect Salmonella in hydrodynamic pressure (HDP)-treated chicken using molecular beacon probes available as a commercial kit (iQ-Check, Bio-Rad Laboratories). The sensitivity and accuracy of the assay were compared with the conventional USDA microbiological procedure using artificially contaminated minced chicken. Chicken fillets were irradiated at 10 kGy to completely destroy any naturally occurring Salmonella. These fillets were minced and inoculated with as low as 2+/-1 cfu of S. typhimurium per 25 g chicken. The minced chicken samples were vacuum packed in multi-layer barrier bags, heat shrunk, and treated with HDP. Results showed that all inoculated samples (n=36) were detected by the PCR assay and conventional USDA procedure. Similarly, all uninoculated controls (n=11) were negative by both PCR assay and USDA procedure. As few as 2+/-1 cfu could be detected from 25 g HDP-treated chicken following 16-18 h enrichment in buffered peptone water. Real-time PCR proved to be an effective method for Salmonella detection in HDP-treated chicken with high sensitivity and more importantly, a rapid and high-throughput detection in 18 h, compared to 3-8 days for the conventional microbiological methods. HDP treatment, which has been reported to reduce spoilage bacteria in various meats, was unable to kill pathogenic Salmonella in minced chicken.

  3. "Real-time" core formation experiments using X-ray tomography at high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Watson, H. C.; Anzures, B.; Yu, T.; Wang, Y.

    2015-12-01

    The process of differentiation is a defining moment in a planet's history. Direct observation of this process at work is impossible in our solar system because it was complete within the first few tens of millions of years. Geochemical and geophysical evidence points to magma ocean scenarios to explain differentiation of large planets such as Earth. Smaller planets and planetesimals likely never achieved the high temperatures necessary for wide scale melting. In these smaller bodies, silicates may have only partially melted, or not melted at all. Furthermore, isotopic signatures in meteorites suggest that some planetesimals differentiated within just a few million years. Achieving efficient core segregation on this rapid timescale is difficult, particularly in a solid or semi-solid silicate matrix. Direct measurements of metallic melt migration velocities have been difficult due to experimental limitations and most previous work has relied on geometric models based on 2-D observations in quenched samples. We have employed a relatively new technique of in-situ, high pressure, high temperature, X-ray micro-tomography coupled with 3-D numerical simulations to evaluate the efficiency of melt percolation in metal/silicate systems. From this, we can place constraints on the timing of core formation in early solar system bodies. Mixtures of olivine and KLB-1 peridotite and up to 12 vol% FeS were pre-synthesized to achieve an initial equilibrium microstructure of silicate and sulfide. The samples were then were then pressed again to ~2GPa, and heated to ~1300°C to collect X-ray tomography images as the partially molten samples were undergoing shear deformation. The reconstructed 3-D images of melt distribution were used as the input for lattice Boltzmann simulations of fluid flow through the melt network and calculations of permeability and melt migration velocity. Our in-situ x-ray tomography results are complemented by traditional 2-D image analysis and high

  4. Argon laser trabeculoplasty as a means of decreasing intraocular pressure from ''normal'' levels in glaucomatous eyes

    SciTech Connect

    Sharpe, E.D.; Simmons, R.J.

    1985-06-15

    The authors conducted a retrospective study of 67 patients (85 eyes) with severe glaucoma to determine whether argon laser trabeculoplasty could reduce intraocular pressures below the ''normal'' range. All patients had initial intraocular pressures of less than or equal to 19 mm Hg. Success was defined as a decrease in intraocular pressure of at least 20%, no increase in medications, stable visual field, and no subsequent glaucoma surgery. After an average follow-up period of 30 months, treatment was successful in 31 cases. One half of the failures occurred by six months and 11 failures (30%) occurred after 12 months. Sixteen patients were able to decrease their medications. Two patients achieved intraocular pressures between 6 and 9 mm Hg and 20 between 10 and 12 mm Hg.

  5. Prognostic Factor Analysis of Intraocular Pressure with Neovascular Glaucoma.

    PubMed

    Nakano, Satoko; Nakamuro, Takako; Yokoyama, Katsuhiko; Kiyosaki, Kunihiro; Kubota, Toshiaki

    2016-01-01

    Purpose. To perform multivariate analysis for identifying independent predictors of elevated intraocular pressure (IOP) with neovascular glaucoma (NVG), including antivascular endothelial growth factor (VEGF) intravitreal injections. Methods. We retrospectively reviewed 142 NVG patients (181 eyes) with ischemic retinal diseases [proliferative diabetic retinopathy (PDR) in 134 eyes, retinal vein occlusion (RVO) in 29, and ocular ischemic syndrome in 18]. We analyzed age, gender, initial/final LogMAR VA, initial/final IOP, extent of iris and/or angle neovascularization, treatments, preexisting complications, concurrent medications, and follow-up duration. Results. The mean follow-up duration was 23.8 ± 18.8 months. At the final follow-up, 125 (72.3%) eyes had IOP ≤ 21 mmHg. NVG patients with RVO had a higher degree of angle closure and higher IOP. NVG with PDR had better IOP and LogMAR VA. Angle closure had the greatest impact on final IOP. Greater than 90% of patients treated with trabeculectomy with mitomycin C (LEC) had persistent declines in IOP (≤21 mmHg). Stand-alone and combination anti-VEGF therapies were not associated with improved long-term prognosis of IOP. Conclusions. Angle closure was found to have the greatest effect on NVG-IOP prognosis. When target IOP values are not obtained after adequate PRP with or without anti-VEGF, early LEC may improve the prognosis of IOP. PMID:27579175

  6. Soft wearable contact lens sensor for continuous intraocular pressure monitoring.

    PubMed

    Chen, Guo-Zhen; Chan, Ion-Seng; Leung, Leo K K; Lam, David C C

    2014-09-01

    Intraocular pressure (IOP) is a primary indicator of glaucoma, but measurements from a single visit to the clinic miss the peak IOP that may occur at night during sleep. A soft chipless contact lens sensor that allows the IOP to be monitored throughout the day and at night is developed in this study. A resonance circuit composed of a thin film capacitor coupled with a sensing coil that can sense corneal curvature deformation is designed, fabricated and embedded into a soft contact lens. The resonance frequency of the sensor is designed to vary with the lens curvature as it changes with the IOP. The frequency responses and the ability of the sensor to track IOP cycles were tested using a silicone rubber model eye. The results showed that the sensor has excellent linearity with a frequency response of ∼8 kHz/mmHg, and the sensor can accurately track fluctuating IOP. These results showed that the chipless contact lens sensor can potentially be used to monitor IOP to improve diagnosis accuracy and treatment of glaucoma.

  7. Prognostic Factor Analysis of Intraocular Pressure with Neovascular Glaucoma

    PubMed Central

    Nakamuro, Takako; Yokoyama, Katsuhiko; Kiyosaki, Kunihiro

    2016-01-01

    Purpose. To perform multivariate analysis for identifying independent predictors of elevated intraocular pressure (IOP) with neovascular glaucoma (NVG), including antivascular endothelial growth factor (VEGF) intravitreal injections. Methods. We retrospectively reviewed 142 NVG patients (181 eyes) with ischemic retinal diseases [proliferative diabetic retinopathy (PDR) in 134 eyes, retinal vein occlusion (RVO) in 29, and ocular ischemic syndrome in 18]. We analyzed age, gender, initial/final LogMAR VA, initial/final IOP, extent of iris and/or angle neovascularization, treatments, preexisting complications, concurrent medications, and follow-up duration. Results. The mean follow-up duration was 23.8 ± 18.8 months. At the final follow-up, 125 (72.3%) eyes had IOP ≤ 21 mmHg. NVG patients with RVO had a higher degree of angle closure and higher IOP. NVG with PDR had better IOP and LogMAR VA. Angle closure had the greatest impact on final IOP. Greater than 90% of patients treated with trabeculectomy with mitomycin C (LEC) had persistent declines in IOP (≤21 mmHg). Stand-alone and combination anti-VEGF therapies were not associated with improved long-term prognosis of IOP. Conclusions. Angle closure was found to have the greatest effect on NVG-IOP prognosis. When target IOP values are not obtained after adequate PRP with or without anti-VEGF, early LEC may improve the prognosis of IOP. PMID:27579175

  8. Hypobaric Hypoxia: Effects on Intraocular Pressure and Corneal Thickness

    PubMed Central

    Di Blasio, Dario; Pescosolido, Nicola

    2014-01-01

    Objective. The purpose of this study focused on understanding the mechanisms underlying ocular hydrodynamics and the changes which occur in the eyes of subjects exposed to hypobaric hypoxia (HH) to permit the achievement of more detailed knowledge in glaucomatous disease. Methods. Twenty male subjects, aged 32 ± 5 years, attending the Italian Air Force, were enrolled for this study. The research derived from hypobaric chamber, using helmet and mask supplied to jet pilotes connected to oxygen cylinder and equipped with a preset automatic mixer. Results. The baseline values of intraocular pressure (IOP), recorded at T1, showed a mean of 16 ± 2.23 mmHg, while climbing up to 18,000 feet the mean value was 13.7 ± 4.17 mmHg, recorded at T2. The last assessment was performed returning to sea level (T4) where the mean IOP value was 12.8 ± 2.57 mmHg, with a significant change (P < 0.05) compared to T1. Pachymetry values related to corneal thickness in conditions of hypobarism revealed a statistically significant increase (P < 0.05). Conclusions. The data collected in this research seem to confirm the increasing outflow of aqueous humor (AH) in the trabecular meshwork (TM) under conditions of HH. PMID:24550712

  9. Intraocular Pressure Induced Retinal Changes Identified Using Synchrotron Infrared Microscopy

    PubMed Central

    Chow, Seong Hoong; Wang, Jiang-Hui; He, Zheng; Nguyen, Christine; Lin, Tsung-Wu; Bui, Bang V.

    2016-01-01

    Infrared (IR) spectroscopy has been used to quantify chemical and structural characteristics of a wide range of materials including biological tissues. In this study, we examined spatial changes in the chemical characteristics of rat retina in response to intraocular pressure (IOP) elevation using synchrotron infrared microscopy (SIRM), a non-destructive imaging approach. IOP elevation was induced by placing a suture around the eye of anaesthetised rats. Retinal sections were collected onto transparent CaF2 slides 10 days following IOP elevation. Using combined SIRM spectra and chemical mapping approaches it was possible to quantify IOP induced changes in protein conformation and chemical distribution in various layers of the rat retina. We showed that 10 days following IOP elevation there was an increase in lipid and protein levels in the inner nuclear layer (INL) and ganglion cell layer (GCL). IOP elevation also resulted in an increase in nucleic acids in the INL. Analysis of SIRM spectra revealed a shift in amide peaks to lower vibrational frequencies with a more prominent second shoulder, which is consistent with the presence of cell death in specific layers of the retina. These changes were more substantial in the INL and GCL layers compared with those occurring in the outer nuclear layer. These outcomes demonstrate the utility of SIRM to quantify the effect of IOP elevation on specific layers of the retina. Thus SIRM may be a useful tool for the study of localised tissue changes in glaucoma and other eye diseases. PMID:27711151

  10. Effect of a tight necktie on intraocular pressure

    PubMed Central

    Teng, C; Gurses-Ozden, R; Liebmann, J M; Tello, C; Ritch, R

    2003-01-01

    Aim: To evaluate the effect of a tight necktie on intraocular pressure (IOP) measurement using Goldmann applanation tonometry. Methods: 40 eyes of 20 normal subjects and 20 open angle glaucoma patients (all male) were enrolled. IOP was measured with an open shirt collar, 3 minutes after placing a tight necktie, and 3 minutes after loosening it. All measurements were made by the same examiner. Results: Mean IOP in normal subjects increased by 2.6 (SD 3.9) mm Hg (p=0.008, paired t test; range −3 to +14 mm Hg) and in glaucoma patients by 1.0 (1.8) mm Hg (p=0.02, paired t test; range −2 to +4.5 mm Hg). In normal subjects, IOP in 12 eyes was increased by ⩾2 mm Hg and in seven eyes by ⩾4 mm Hg. In glaucoma patients, IOP in six eyes was increased by ⩾2 mm Hg and in two eyes by ⩾4 mm Hg. Conclusion: A tight necktie increases IOP in both normal subjects and glaucoma patients and could affect the diagnosis and management of glaucoma. PMID:12881330

  11. Impact factors on intraocular pressure measurements in healthy subjects

    PubMed Central

    Theelen, T; Meulendijks, C F M; Geurts, D E M; van Leeuwen, A; Voet, N B M; Deutman, A F

    2004-01-01

    Aim: To evaluate whether intraocular pressure (IOP) calculation by applanation tonometry is determined more essentially by the subject’s neck position or by neck constriction. Methods: 23 right eyes of 23 healthy subjects (12 male, 11 female) were included. IOP was measured by applanation tonometry with the TonoPen on sitting participants under four different conditions: with open collar upright (A) or with the head in the headrest of a slit lamp (B), with a tight necktie upright (C) or in slit lamp position (D). All measurements with neck constriction were performed 3 minutes after placing the necktie. Results: Mean IOP was 16.9 (SD 2.3) mm Hg (range 11–21 mm Hg) (A), 18.1 (SD 2.2) mm Hg (range 14–22 mm Hg) (B), 17.9 (SD 2.9) mm Hg (range 12–25 mm Hg) (C) and 18.7 (SD 2.7) mm Hg (range 13–24 mm Hg) (D). Mean IOP increased by 1.3 (SD 2.6) mm Hg (p = 0.028, paired t test, range +0.2 to +2.4 mm Hg) if subjects changed position from A to B. There was no statistically significant difference between measurements with or without neck constriction. Conclusion: Applanation tonometry may be inaccurate if performed in slit lamp position. In contrast, tight neckties do not significantly affect IOP evaluation in healthy subjects. PMID:15548801

  12. Mechanisms for vasopressin effects on intraocular pressure in anesthetized rats

    NASA Technical Reports Server (NTRS)

    Balaban, C. D.; Palm, D. E.; Shikher, V.; Searles, R. V.; Keil, L. C.; Severs, W. B.

    1997-01-01

    Continuous intracameral infusions of a balanced salt solution (0.175 microliter min-1) have been reported to raise intraocular pressure (IOP) in anesthetized rats. Palm et al. (1995) previously reported that this effect was attenuated significantly by inclusion of arginine-vasopressin (AVP, 10 ng 0.175 microliter-1) in the infusate. This study used experimental and computer simulation methods to investigate factors underlying these changes in IOP. First, constant intracameral infusions of artificial cerebrospinal fluid (aCSF) at different fixed rates (0.049-0.35 microliter min-1) were used to estimate the outflow resistance. Secondly, IOP responses were measured during an 2 hr intracameral infusion of either aCSF or AVP that was the sum of a small constant component (0.05 microliter min-1) and a larger periodic component (0.25 microliter min-1, cycling for 4 min on, then 4 min off); the mean infusion rate was 0.175 microliter min-1. As shown previously for 0.175 microliter min-1 constant infusions, the periodic aCSF infusion induced a significant rise in IOP that was attenuated by AVP administration. Complex demodulation analysis and the estimated gain parameter of a second order transfer function fit to the periodic responses indicated that outflow resistance increased significantly during the infusions in both aCSF and AVP groups, but that the indices of resistance did not differ significantly between aCSF and AVP infused eyes. This finding implies that changes in outflow resistance do not explain the difference in IOP responses to intracameral aCSF and AVP. The two responses differed significantly, though, in damping factors, such that the aCSF responses were considerably more underdamped than the AVP responses. It is hypothesized that aCSF-induced increase in IOP reflects both (1) a small component reflecting increased outflow resistance and (2) a larger non-resistive component. Since the non-resistive component is insensitive to pretreatment with acetazolamide

  13. A New Algorithm for Real-Time Tsunami Forecast Using a Dense Network of Cabled Ocean-Bottom Pressure Gauges

    NASA Astrophysics Data System (ADS)

    Yamamoto, N.; Aoi, S.; Hirata, K.; Kunugi, T.; Nakamura, H.; Suzuki, W.

    2014-12-01

    We started to develop a new algorithm for real-time tsunami forecast based on offshore tsunami observations with 150 cabled ocean-bottom pressure gauges of the Seafloor Observation Network for Earthquakes and Tsunamis (S-net), under construction along the Japan Trench (Kanazawa et al., 2012, JpGU; Uehira et al., 2012, AGU). The most important concept on the new algorithm is involving any type and/or form uncertainties in the tsunami forecast, which cannot be dealt with any of standard linear/nonlinear least square approaches. We first construct a tsunami scenario bank (TSB). It contains offshore tsunami waveforms at the 150 stations and maximum coastal tsunami heights, calculated using nonlinear long-wave theory with runup boundary condition from any possible tsunami sources (fault models) that affect target coastal regions. From TSB, then we quickly explore a range of several suitable tsunami scenarios, that can explain offshore observations. At the same time, maximum possible tsunami heights along the target coastlines, coupled with selected scenarios, are predicted. In the near future, it is possible to forecast real-time tsunami inundation by adding its component in TSB under the same strategy. In this study, we focus on near-field tsunami occurring off the Pacific coast of Tohoku and Hokkaido. Provisionally, we generate 1848 tsunami scenarios, prepared for a research project of nationwide Probabilistic Tsunami Hazard Assessment for Japan (Hirata et al., 2014, AOGS), to construct TSB. For a given pseudo "observed waveforms", the developing algorithm rapidly picks up an allowable range of tsunami scenarios from TSB. In this procedure, we use multiple indexes such as correlation coefficient, sum of squared residual, as well as geometric mean and geometric standard deviation in ratios of scenarios to observations. Use of multiple indexes rather than any single index as linear inversion does reinforce to obtain robust tsunami forecast.

  14. Multi-index method using offshore ocean-bottom pressure data for real-time tsunami forecast

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naotaka; Aoi, Shin; Hirata, Kenji; Suzuki, Wataru; Kunugi, Takashi; Nakamura, Hiromitsu

    2016-07-01

    We developed a real-time tsunami forecast method using only pressure data collected from the bottom of the ocean via a dense offshore observation network. The key feature of the method is rapid matching between offshore tsunami observations and pre-calculated offshore tsunami spatial distributions. We first calculate the tsunami waveforms at offshore stations and the maximum coastal tsunami heights from any possible tsunami source model and register them in the proposed Tsunami Scenario Bank (TSB). When a tsunami occurs, we use multiple indices to quickly select dozens of appropriate tsunami scenarios that can explain the offshore observations. At the same time, the maximum coastal tsunami heights coupled with the selected tsunami scenarios are forecast. We apply three indices, which are the correlation coefficient and two kinds of variance reductions normalized by the L2-norm of either the observation or calculation, to match the observed spatial distributions with the pre-calculated spatial distributions in the TSB. We examine the ability of our method to select appropriate tsunami scenarios by conducting synthetic tests using a scenario based on "pseudo-observations." For these tests, we construct a tentative TSB, which contains tsunami waveforms at locations in the Seafloor Observation Network for Earthquakes and Tsunamis along the Japan Trench and maximum coastal tsunami heights, using about 2000 tsunami source models along the Japan Trench. Based on the test results, we confirm that the method can select appropriate tsunami scenarios within a certain precision by using the two kinds of variance reductions, which are sensitive to the tsunami size, and the correlation coefficient, which is sensitive to the tsunami source location. In this paper, we present the results and discuss the characteristics and behavior of the multi-index method. The addition of tsunami inundation components to the TSB is expected to enable the application of this method to real-time

  15. The Real-Time Wall Interference Correction System of the NASA Ames 12-Foot Pressure Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Ulbrich, Norbert

    1998-01-01

    An improved version of the Wall Signature Method was developed to compute wall interference effects in three-dimensional subsonic wind tunnel testing of aircraft models in real-time. The method may be applied to a full-span or a semispan model. A simplified singularity representation of the aircraft model is used. Fuselage, support system, propulsion simulator, and separation wake volume blockage effects are represented by point sources and sinks. Lifting effects are represented by semi-infinite line doublets. The singularity representation of the test article is combined with the measurement of wind tunnel test reference conditions, wall pressure, lift force, thrust force, pitching moment, rolling moment, and pre-computed solutions of the subsonic potential equation to determine first order wall interference corrections. Second order wall interference corrections for pitching and rolling moment coefficient are also determined. A new procedure is presented that estimates a rolling moment coefficient correction for wings with non-symmetric lift distribution. Experimental data obtained during the calibration of the Ames Bipod model support system and during tests of two semispan models mounted on an image plane in the NASA Ames 12 ft. Pressure Wind Tunnel are used to demonstrate the application of the wall interference correction method.

  16. A chair for cuffless real-time estimation of systolic blood pressure based on pulse transit time.

    PubMed

    Tang, Zunyi; Sekine, Masaki; Tamura, Toshiyo; Yoshida, Masaki; Chen, Wenxi

    2015-01-01

    This study presents an unobtrusive cuffless blood pressure (BP) monitoring system for estimating beat-by-beat systolic blood pressure (SBP) in real-time based on pulse transit time (PTT). The system mainly includes an electrocardiograph with three conductive textile electrodes, a pulse monitor with a LED and a photodetector, a control circuit with a Bluetooth module, and a battery, all of which are mounted on a common armchair to measure ECG and photoplethysmography (PPG) signals from users during sitting on the armchair. The measured ECG and PPG data are transmitted to the software terminal installed on a tablet PC and are further derived to obtain a series of PTT for estimating beat-by-beat BP using Chen's method. We had 9 healthy subjects undergo the BP monitoring experiments of still sitting on a chair for 3 minutes, lying on a bed for 10 minutes, and pedaling using ergometer for 11 minutes in order to assess the accuracy of the estimated BP. A Finometer and a cuff-type BP meter were used as references in the experiments. Preliminary results showed that the mean error and mean absolute difference (MAD) of estimated BP were within -0.5 ± 5.3 mmHg and 4.1 ± 3.4 mmHg, respectively, compared to references. The result suggests that the proposed BP estimation system has the potential for long-term home BP monitoring. PMID:26737443

  17. Driving time modulates accommodative response and intraocular pressure.

    PubMed

    Vera, Jesús; Diaz-Piedra, Carolina; Jiménez, Raimundo; Morales, José M; Catena, Andrés; Cardenas, David; Di Stasi, Leandro L

    2016-10-01

    Driving is a task mainly reliant on the visual system. Most of the time, while driving, our eyes are constantly focusing and refocusing between the road and the dashboard or near and far traffic. Thus, prolonged driving time should produce visual fatigue. Here, for the first time, we investigated the effects of driving time, a common inducer of driver fatigue, on two ocular parameters: the accommodative response (AR) and the intraocular pressure (IOP). A pre/post-test design has been used to assess the impact of driving time on both indices. Twelve participants (out of 17 recruited) completed the study (5 women, 24.42±2.84years old). The participants were healthy and active drivers with no visual impairment or pathology. They drove for 2h in a virtual driving environment. We assessed AR and IOP before and after the driving session, and also collected subjective measures of arousal and fatigue. We found that IOP and AR decreased (i.e., the accommodative lag increased) after the driving session (p=0.03 and p<0.001, respectively). Moreover, the nearest distances tested (20cm, 25cm, and 33cm) induced the highest decreases in AR (corrected p-values<0.05). Consistent with these findings, the subjective levels of arousal decreased and levels of fatigue increased after the driving session (all p-values<0.001). These results represent an innovative step towards an objective, valid, and reliable assessment of fatigue-impaired driving based on visual fatigue signs. PMID:27235337

  18. Nanosponge-Mediated Drug Delivery Lowers Intraocular Pressure

    PubMed Central

    Lambert, Wendi S.; Carlson, Brian J.; van der Ende, Alice E.; Shih, Grace; Dobish, Julia N.; Calkins, David J.; Harth, Eva

    2015-01-01

    Purpose We examined the efficacy of an extended-release drug delivery system, nanosponge (NS) encapsulated compounds, administered intravitreally to lower intraocular pressure (IOP) in mice. Methods Bilateral ocular hypertension was induced in mice by injecting microbeads into the anterior chamber. Hypertensive mice received NS loaded with ocular hypotensive drugs via intravitreal injection and IOP was monitored. Retinal deposition and retinal ganglion cell (RGC) uptake of Neuro-DiO were examined following intravitreal injection of Neuro-DiO-NS using confocal microscopy. Results Brimonidine-loaded NS lowered IOP 12% to 30% for up to 6 days (P < 0.02), whereas travoprost-NS lowered IOP 19% to 29% for up to 4 days (P < 0.02) compared to saline injection. Three bimatoprost NS were tested: a 400-nm NS and two 700-nm NS with amorphous (A-NS) or amorphous/crystalline (AC-NS) crosslinkers. A single injection of 400 nm NS lowered IOP 24% to 33% for up to 17 days compared to saline, while A-NS and AC-NS lowered IOP 22% to 32% and 18% to 26%, respectively, for up to 32 days (P < 0.046). Over time retinal deposition of Neuro-DiO increased from 19% to 71%; Neuro-DiO released from NS was internalized by RGCs. Conclusions A single injection of NS can effectively deliver ocular hypotensive drugs in a linear and continuous manner for up to 32 days. Also, NS may be effective at targeting RGCs, the neurons that degenerate in glaucoma. Translational Relevance Patient compliance is a major issue in glaucoma. The use of NS to deliver a controlled, sustained release of therapeutics could drastically reduce the number of patients that progress to vision loss in this disease. PMID:25599009

  19. Lacrimal gland choristoma in a preterm infant, presenting with spontaneous hyphema and increased intraocular pressure.

    PubMed

    Ranganathan, D; Lenhart, P; Hubbard, G B; Grossniklaus, H

    2010-11-01

    We report a case of intraocular lacrimal gland choristoma presenting very early in a preterm infant with hyphema, a mass lesion and raised intraocular pressure. Enucleation of the involved eye, which is the treatment in most cases, was performed and prosthesis was fitted successfully. An interesting additional finding in our patient was a choroidal defect, not reported to date with other cases in the literature.

  20. A long-lasting hypotensive effect of topical diltiazem on the intraocular pressure in conscious rabbits.

    PubMed

    Santafé, J; Martínez de Ibarreta, M J; Segarra, J; Melena, J

    1997-05-01

    The effect of calcium channel blockers on intraocular pressure and aqueous humor dynamics remains still controversial, although preliminary evidence suggests that these drugs may be beneficial in the management of ocular hypertension and low-tension glaucoma. Having previously reported the ocular hypotensive effect of topical nifedipine and verapamil in albino rabbits, the original aim of the present work was to evaluate the effect of topical diltiazem on aqueous humor dynamics in this species. Intraocular pressure was measured with a manual applanation tonometer. The experiments examining the ocular actions of diltiazem were carried out in two stages. In the first one, short term effects of topical diltiazem on intraocular pressure were studied in groups of 13 albino rabbits receiving 8 different doses of the drug in order to obtain a dose-response curve. Tonographies were performed in 13 anaesthetized animals before and 90 min after drug instillation. In a second phase, the persistence of the effect of diltiazem on intraocular pressure was examined in 6 groups of 10 rabbits each receiving three different doses of the drug. Topical diltiazem was found to lower intraocular pressure in a dose-related fashion. The maximum response to diltiazem was greater and the ED50 lower than those previously reported for nifedipine and verapamil. In the tonographic study, diltiazem was shown to reduce the facility of aqueous humor outflow and inflow. Diltiazem exhibited a long lasting effect on intraocular pressure that was again dose-related. Depending on the dose administered, the calculated time necessary for the peak effect to be halved ranged from 0.6 to 7.0 days. Due to the intensity and the persistence of its intraocular pressure-lowering effect, diltiazem shows great potential for the treatment of glaucoma, since a daily or less frequent administration may be enough to control ocular hypertension.

  1. Apparatus and method for non-contact, acoustic resonance determination of intraocular pressure

    DOEpatents

    Sinha, Dipen N.; Wray, William O.

    1994-01-01

    Apparatus and method for measuring intraocular pressure changes in an eye under investigation by detection of vibrational resonances therein. An ultrasonic transducer operating at its resonant frequency is amplitude modulated and swept over a range of audio frequencies in which human eyes will resonate. The output therefrom is focused onto the eye under investigation, and the resonant vibrations of the eye observed using a fiber-optic reflection vibration sensor. Since the resonant frequency of the eye is dependent on the pressure therein, changes in intraocular pressure may readily be determined after a baseline pressure is established.

  2. Apparatus and method for non-contact, acoustic resonance determination of intraocular pressure

    DOEpatents

    Sinha, D.N.; Wray, W.O.

    1994-12-27

    The apparatus and method for measuring intraocular pressure changes in an eye under investigation by detection of vibrational resonances therein. An ultrasonic transducer operating at its resonant frequency is amplitude modulated and swept over a range of audio frequencies in which human eyes will resonate. The output therefrom is focused onto the eye under investigation, and the resonant vibrations of the eye observed using a fiber-optic reflection vibration sensor. Since the resonant frequency of the eye is dependent on the pressure therein, changes in intraocular pressure may readily be determined after a baseline pressure is established. 3 figures.

  3. Intraocular pressure and glaucoma: Is physical exercise beneficial or a risk?

    PubMed

    McMonnies, Charles William

    2016-01-01

    Intraocular pressure may become elevated with muscle exertion, changes in body position and increased respiratory volumes, especially when Valsalva manoeuver mechanisms are involved. All of these factors may be present during physical exercise, especially if hydration levels are increased. This review examines the evidence for intraocular pressure changes during and after physical exercise. Intraocular pressure elevation may result in a reduction in ocular perfusion pressure with the associated possibility of mechanical and/or ischaemic damage to the optic nerve head. A key consideration is the possibility that, rather than being beneficial for patients who are susceptible to glaucomatous pathology, any intraocular pressure elevation could be detrimental. Lower intraocular pressure after exercise may result from its elevation causing accelerated aqueous outflow during exercise. Also examined is the possibility that people who have lower frailty are more likely to exercise as well as less likely to have or develop glaucoma. Consequently, lower prevalence of glaucoma would be expected among people who exercise. The evidence base for this topic is deficient and would be greatly improved by the availability of tonometry assessment during dynamic exercise, more studies which control for hydration levels, and methods for assessing the potential general health benefits of exercise against any possibility of exacerbated glaucomatous pathology for individual patients who are susceptible to such changes.

  4. Real-Time, Non-Intrusive Detection of Liquid Nitrogen in Liquid Oxygen at High Pressure and High Flow

    NASA Technical Reports Server (NTRS)

    Singh, Jagdish P.; Yueh, Fang-Yu; Kalluru, Rajamohan R.; Harrison, Louie

    2012-01-01

    An integrated fiber-optic Raman sensor has been designed for real-time, nonintrusive detection of liquid nitrogen in liquid oxygen (LOX) at high pressures and high flow rates in order to monitor the quality of LOX used during rocket engine ground testing. The integrated sensor employs a high-power (3-W) Melles Griot diode-pumped, solid-state (DPSS), frequency-doubled Nd:YAG 532- nm laser; a modified Raman probe that has built-in Raman signal filter optics; two high-resolution spectrometers; and photomultiplier tubes (PMTs) with selected bandpass filters to collect both N2 and O2 Raman signals. The PMT detection units are interfaced with National Instruments Lab- VIEW for fast data acquisition. Studies of sensor performance with different detection systems (i.e., spectrometer and PMT) were carried out. The concentration ratio of N2 and O2 can be inferred by comparing the intensities of the N2 and O2 Raman signals. The final system was fabricated to measure N2 and O2 gas mixtures as well as mixtures of liquid N2 and LOX

  5. An effective approach for coupling direct analysis in real time with atmospheric pressure drift tube ion mobility spectrometry.

    PubMed

    Keelor, Joel D; Dwivedi, Prabha; Fernández, Facundo M

    2014-09-01

    Drift tube ion mobility spectrometry (DTIMS) has evolved as a robust analytical platform routinely used for screening small molecules across a broad suite of chemistries ranging from food and pharmaceuticals to explosives and environmental toxins. Most modern atmospheric pressure IM detectors employ corona discharge, photoionization, radioactive, or electrospray ion sources for efficient ion production. Coupling standalone DTIMS with ambient plasma-based techniques, however, has proven to be an exceptional challenge. Device sensitivity with near-ground ambient plasma sources is hindered by poor ion transmission at the source-instrument interface, where ion repulsion is caused by the strong electric field barrier of the high potential ion mobility spectrometry (IMS) inlet. To overcome this shortfall, we introduce a new ion source design incorporating a repeller point electrode used to shape the electric field profile and enable ion transmission from a direct analysis in real time (DART) plasma ion source. Parameter space characterization studies of the DART DTIMS setup were performed to ascertain the optimal configuration for the source assembly favoring ion transport. Preliminary system capabilities for the direct screening of solid pharmaceuticals are briefly demonstrated. PMID:24903510

  6. An Effective Approach for Coupling Direct Analysis in Real Time with Atmospheric Pressure Drift Tube Ion Mobility Spectrometry

    NASA Astrophysics Data System (ADS)

    Keelor, Joel D.; Dwivedi, Prabha; Fernández, Facundo M.

    2014-09-01

    Drift tube ion mobility spectrometry (DTIMS) has evolved as a robust analytical platform routinely used for screening small molecules across a broad suite of chemistries ranging from food and pharmaceuticals to explosives and environmental toxins. Most modern atmospheric pressure IM detectors employ corona discharge, photoionization, radioactive, or electrospray ion sources for efficient ion production. Coupling standalone DTIMS with ambient plasma-based techniques, however, has proven to be an exceptional challenge. Device sensitivity with near-ground ambient plasma sources is hindered by poor ion transmission at the source-instrument interface, where ion repulsion is caused by the strong electric field barrier of the high potential ion mobility spectrometry (IMS) inlet. To overcome this shortfall, we introduce a new ion source design incorporating a repeller point electrode used to shape the electric field profile and enable ion transmission from a direct analysis in real time (DART) plasma ion source. Parameter space characterization studies of the DART DTIMS setup were performed to ascertain the optimal configuration for the source assembly favoring ion transport. Preliminary system capabilities for the direct screening of solid pharmaceuticals are briefly demonstrated.

  7. Intraocular pressure in captive American flamingos (Phoenicopterus ruber) as measured by rebound tonometry.

    PubMed

    Molter, Christine M; Hollingsworth, Steven R; Kass, Philip H; Chinnadurai, Sathya K; Wack, Raymund F

    2014-09-01

    Intraocular pressure was measured using rebound tonometry in American flamingos (Phoenicopterus ruber), with the head in an upright standing position and when lowered in a feeding position, to establish a reference range. Mean +/- standard deviation (SD) (range) intraocular pressure for flamingos with the head in an upright position was right eye (OD)= 10.9 +/- 1.8 mm Hg (7-15 mm Hg) and left eye (OS) = 11.1 +/- 2.3 mm Hg (8-21 mm Hg). Median intraocular pressure for flamingos with the head in an upright position was OD and OS = 11 mm Hg. Mean intraocular pressure for flamingos with the head in a feeding position was OD = 14.3 +/- 2.5 mm Hg (10-22 mm Hg) and OS = 14.4 +/- 2.7 mm Hg (11-24 mm Hg), which were significantly higher. Median intraocular pressure for flamingos with the head in a feeding position was OD and OS = 14 mm Hg.

  8. Relationship between homocysteine and intraocular pressure in men and women: A population-based study.

    PubMed

    Leibovitzh, Haim; Cohen, Eytan; Levi, Amos; Kramer, Michal; Shochat, Tzippy; Goldberg, Elad; Krause, Ilan

    2016-09-01

    The relationship between homocysteine levels and glaucoma has been questioned in previous studies without conclusive results. In the current study, we assessed the relationship between homocysteine levels and intraocular pressure which is one of the main factors in the development of glaucoma in men and women.A retrospective cross-sectional analysis of a database from a screening center in Israel which assessed 11,850 subjects, within an age range 20 to 80 years. The relationship between homocysteine and intraocular pressure has been investigated by comparing intraocular pressure in subjects with elevated and normal homocysteine and by comparing homocysteine levels in subjects with elevated and normal intraocular pressure. In addition, we compared the levels of homocysteine in subjects with and without a confirmed diagnosis of glaucoma.The mean IOP (±SD) in subjects with normal homocysteine levels(≤15 μmol/L) was 13.2 ± 2.3 mm Hg and 13.4 ± 2.4 mm Hg in those with high homocysteine levels (>15 μmol/L) (P < 0.008, 95% confidence interval [CI] 0.3-0.09).Nonetheless, after multivariate adjustment for age, gender, vitamin B12, and folic acid statistical significance was no longer demonstrated (P = 0.37). Mean homocysteine levels (±SD) in subjects with normal intraocular pressure of ≤ 21 mm Hg was 11.7 ± 5.5 μmol/L and 12.09 ± 3.43 μmol/L in those with elevated intraocular pressure (P = 0.4, 95%CI 1.1-1.8). Mean homocysteine levels (±SD) in subjects with glaucoma were 11.2 ± 3.5 μmol/L compared to 11.7 ± 5.5 μmol/L in subjects without glaucoma and normal intraocular pressure ≤ 21 mm Hg (P = 0.4, 95% CI 1.2-2.1).The current study displays no clinical correlation between the homocysteine level and the intraocular pressure. Homocysteine may not be used as a predictive parameter to recognize those subjects prone to develop elevated intraocular pressure. PMID:27661027

  9. Effect of seasons upon intraocular pressure in healthy population of China.

    PubMed

    Qureshi, I A; Xi, X R; Lu, H J; Wu, X D; Huang, Y B; Shiarkar, E

    1996-06-01

    Studies have been shown that intraocular pressure (IOP) shows a seasonal variation, but amount of change differs from study to study. The variability in their results may be due to negligence of factors that can affect IOP. Due to differences in environmental conditions of China than other countries, we investigated seasonal variations in IOP of 103 healthy male Chinese of Shanghai. IOP was measured each month over the course of fourteen months with the Goldmann applanation tonometer. The average intraocular pressures in the winter months were higher than those in the spring, summer, and autumn months. The IOP difference between winter and summer months was found to be 1.4 +/- 0.7 mmHg. This study confirms that season influences IOP. As compared to other nations, effect of seasons on IOP seems to be somewhat less pronounced in Chinese. The possible mechanisms, responsible for the seasonal variation of intraocular pressure, are also postulated.

  10. Sustained reduction of intraocular pressure in humans with the calcium channel blocker verapamil.

    PubMed

    Abelson, M B; Gilbert, C M; Smith, L M

    1988-02-15

    We investigated the effect of the calcium channel blocker verapamil on intraocular pressure in human volunteers. In the initial trial, 15 subjects with untreated ocular hypertension were tested. After a baseline measurement was obtained with applanation tonometry, a 40-microliter drop of verapamil, 1.25 mg/ml, was instilled in one eye. After 30 minutes, a second reading was taken. In a subsequent trial of 12 untreated ocular hypertensive subjects, the duration of action was determined using the same dose and method of delivery. Results showed that verapamil elicited a mean +/- S.E.M. change in intraocular pressure of -3.8 +/- 0.900 mm Hg in the treated eye, and -1.6 +/- 0.400 mm Hg in the untreated eye. This reduction was statistically different in both eyes (treated eye, P = .0007; untreated eye, P = .005). This decrease in intraocular pressure remained statistically significant when compared to predrug baseline values for up to ten hours.

  11. Reference intervals for intraocular pressure measured by rebound tonometry in ten raptor species and factors affecting the intraocular pressure.

    PubMed

    Reuter, Anne; Müller, Kerstin; Arndt, Gisela; Eule, Johanna Corinna

    2011-09-01

    Intraocular pressure (IOP) was measured with the TonoVet rebound tonometer in 10 raptor species, and possible factors affecting IOP were investigated. A complete ophthalmic examination was performed, and IOP was assessed in 2 positions, upright and dorsal recumbency, in 237 birds belonging to the families Accipitridae, Falconidae, Strigidae, and Tytonidae. Mean IOP values of healthy eyes were calculated for each species, and differences between families, species, age, sex, left and right eye, as well as the 2 body positions were evaluated. Physiologic fluctuations of IOP were assessed by measuring IOP serially for 5 days at the same time of day in 15 birds of 3 species. Results showed IOP values varied by family and species, with the following mean IOP values (mm Hg +/- SD) determined: white-tailed sea eagle (Haliaeetus albicilla), 26.9 +/- 5.8; red kite (Milvus milvus), 13.0 +/- 5.5; northern goshawk (Accipiter gentilis), 18.3 +/- 3.8; Eurasian sparrowhawk (Accipiter nisus), 15.5 +/- 2.5; common buzzard (Buteo buteo), 26.9 +/- 7.0; common kestrel (Falco tinnunculus), 9.8 +/- 2.5; peregrine falcon, (Falco peregrinus), 12.7 +/- 5.8; tawny owl (Strix aluco), 9.4 +/- 4.1; long-eared owl (Asio otus), 7.8 +/- 3.2; and barn owl (Tyto alba), 10.8 +/- 3.8. No significant differences were found between sexes or between left and right eyes. In goshawks, common buzzards, and common kestrels, mean IOP was significantly lower in juvenile birds than it was in adult birds. Mean IOP differed significantly by body position in tawny owls (P = .01) and common buzzards (P = .04). By measuring IOP over several days, mean physiologic variations of +/- 2 mm Hg were detected. Differences in IOP between species and age groups should be considered when interpreting tonometric results. Physiologic fluctuations of IOP may occur and should not be misinterpreted. These results show that rebound tonometry is a useful diagnostic tool in measuring IOP in birds of prey because it provides rapid

  12. Implantable micromechanical parylene-based pressure sensors for unpowered intraocular pressure sensing

    NASA Astrophysics Data System (ADS)

    Chen, Po-Jui; Rodger, Damien C.; Agrawal, Rajat; Saati, Saloomeh; Meng, Ellis; Varma, Rohit; Humayun, Mark S.; Tai, Yu-Chong

    2007-10-01

    This paper presents the first implantable, unpowered, parylene-based microelectromechanical system (MEMS) pressure sensor for intraocular pressure (IOP) sensing. From in situ mechanical deformation of the compliant spiral-tube structures, this sensor registers pressure variations without electrical or powered signal transduction of any kind. Micromachined high-aspect-ratio polymeric hollow tubes with different geometric layouts are implemented to obtain high-sensitivity pressure responses. An integrated device packaging method has been developed toward enabling minimally invasive suture-less needle-based implantation of the device. Both in vitro and ex vivo device characterizations have successfully demonstrated mmHg resolution of the pressure responses. In vivo animal experiments have also been conducted to verify the biocompatibility and functionality of the implant fixation method inside the eye. Using the proposed implantation scheme, the pressure response of the implant can be directly observed from outside the eye under visible light, with the goal of realizing convenient, direct and faithful IOP monitoring in glaucoma patients.

  13. The intraocular pressure-lowering properties of intravenous paracetamol

    PubMed Central

    van den Heever, Henning; Meyer, David

    2016-01-01

    Aim The aim of this paper was to investigate the intraocular pressure (IOP)-changing properties of a single standard dose of intravenous (IV) paracetamol and compare it to that of topical timolol, oral acetazolamide, and no treatment. Methods A prospective, randomized, investigator-blind, parallel-group study was conducted in 73 eyes of 52 subjects. Subjects received a single dose of IV paracetamol (1 g), oral acetazolamide (250 mg), topical timolol (0.5%, one drop), or no treatment. Baseline IOP was measured, and the measurement was repeated at 1, 2, 4, and 6 hours after treatment. Results Paracetamol reduced IOP from baseline by −10.8% (95% confidence interval [CI]: −4.9% to −16.8%, P=0.146) at 1 hour, −13.3% (95% CI: −8.3% to −18.4%, P=0.045) at 2 hours, −11.8% (95% CI: −5.5% to −18.4%, P=1.000) at 4 hours, and −23.9% (95% CI: −17.8% to −30.1%, P=0.006) at 6 hours after treatment. In the no-treatment group, the change was −2.9% (95% CI: +1.0% to −6.7%, P= referent) at 1 hour, −2.1% (95% CI: +2.9% to −7.2%, P= referent) at 2 hours, −7.6% (95% CI: −3.9% to −11.2%, P= referent) at 4 hours, and −6.9% (95% CI: −3.6% to −10.2%, P= referent) at 6 hours. Acetazolamide reduced IOP by −18.8% (95% CI: −12.7% to −24.8%, P=0.000) at 1 hour, −26.2% (95% CI: −18.2% to −34.2%, P=0.001) at 2 hours, −24.6% (95% CI: −16.9% to −32.3%, P=0.000) after 4 hours, and −26.9% (95% CI: −19.6% to −34.3%, P=0.000) 6 hours after treatment. Timolol reduced IOP by −31.2% (95% CI: −26.7% to −35.7%, P=0.000) at 1 hour, −27.7% (95% CI: −20.7% to −34.8%, P=0.000) at 2 hours, −28.7% (95% CI: −21.1% to −36.2%, P=0.000) at 4 hours, and −21.3% (95% CI: −13.4% to −30.0%, P=0.030) at 6 hours after treatment. The average change in IOP for the no-treatment group was −4.8% (95% CI: −2.6% to −6.9%, P= referent). It was −15.7% (95% CI: −9.3% to −22.1%, P=0.021) for paracetamol, −23.1% (95% CI: −16.4% to

  14. A complex interaction between topical verapamil and timolol on intraocular pressure in conscious rabbits.

    PubMed

    Santafé, J; Martínez de Ibarreta, M J; Segarra, J; Melena, J; Garrido, M

    1996-07-01

    Calcium channel blockers have complex actions on aqueous humour dynamics that seem to depend on the route of drug administration. When applied topically, verapamil and nifedipine effectively lower intraocular pressure. However, these drugs also produce a slight reduction in aqueous humor outflow through the trabecular meshwork whereby they could modify the effect of other drugs on intraocular pressure. As calcium channel blockers could be effective in the management of ocular hypertension and low-tension glaucoma, the aim of the present work was to assess the interaction between verapamil and timolol when both drugs are topically applied to the eye of albino rabbits. Intraocular pressure was measured with a manual applanation tonometer. The effects of 5-6 different doses of each drug alone and the effects of five mixtures of both drugs at fixed concentration ratios (timolol: verapamil 4:1, 2:1, 1:1, 1:2 and 1:4) were evaluated. After measuring baseline intraocular pressure, one 50 microliters drop of the different solutions was instilled in the left eye. Measures of the intraocular pressure were repeated at intervals of 30 min until the maximal effect was reached. Each set of experiments was carried out in a group of 9-11 rabbits. Dose-response curves were fitted with a nonlinear regression microcomputer programme. The median effect plot was constructed as proposed by Chou and Talalay (1981, 1983, 1984). In order to analyse the nature of the interaction between both drugs, the observed effect was compared with the theoretically expected one and the combination indices, that relate the doses of verapamil and timolol present in the mixtures with the doses of both drugs separately which are equieffective with the combination, were calculated. The effects of verapamil and timolol followed the principle of the mass action law when administered alone. Nevertheless, no adequate dose-response relationship was obtained when the mixtures of both drugs were applied. In

  15. An integrated instrument for rapidly deforming living cells using rapid pressure pulses and simultaneously monitoring applied strain in near real time

    NASA Astrophysics Data System (ADS)

    Green, M. E.; Goforth, P. B.; Satin, L. S.; Love, B. J.

    2010-12-01

    Because many types of living cells are sensitive to applied strain, different in vitro models have been designed to elucidate the cellular and subcellular processes that respond to mechanical deformation at both the cell and tissue level. Our focus was to improve upon an already established strain system to make it capable of independently monitoring the deflection and applied pressure delivered to specific wells of a commercially available, deformable multiwell culture plate. To accomplish this, we devised a custom frame that was capable of mounting deformable 6 or 24 well plates, a pressurization system that could load wells within the plates, and a camera-based imaging system which was capable of capturing strain responses at a sufficiently high frame rate. The system used a user defined program constructed in Labview® to trigger plate pressurization while simultaneously allowing the deflection of the silicone elastomeric plate bottoms to be imaged in near real time. With this system, up to six wells could be pulsed simultaneously using compressed air or nitrogen. Digital image capture allowed near-real time monitoring of applied strain, strain rate, and the cell loading profiles. Although our ultimate goal is to determine how different strain rates applied to neurons modulates their intrinsic biochemical cascades, the same platform technology could be readily applied to other systems. Combining commercially available, deformable multiwell plates with a simple instrument having the monitoring capabilities described here should permit near real time calculations of stretch-induced membrane strain in multiple wells in real time for a wide variety of applications, including high throughput drug screening.

  16. [The effect of crystalline lens extraction on intraocular pressure in patients with primary open-angle glaucoma].

    PubMed

    Macarie, S; Macarie, Daniela

    2013-01-01

    This issue presents the results of a study on patients with cataract and primary open angle glaucoma who suffered lens extraction for cataract. We analise the effects of the lens extraction on the level of intraocular pressure at this patients.

  17. Intra-Ocular Pressure Measurement in a Patient with a Thin, Thick or Abnormal Cornea

    PubMed Central

    Clement, Colin I.; Parker, Douglas G.A.; Goldberg, Ivan

    2016-01-01

    Accurate measurement of intra-ocular pressure is a fundamental component of the ocular examination. The most common method of measuring IOP is by Goldmann applanation tonometry, the accuracy of which is influenced by the thickness and biomechanical properties of the cornea. Algorithms devised to correct for corneal thickness to estimate IOP oversimplify the effects of corneal biomechanics. The viscous and elastic properties of the cornea influence IOP measurements in unpredictable ways, a finding borne out in studies of patients with inherently abnormal and surgically altered corneal biomechanics. Dynamic contour tonometry, rebound tonometry and the ocular response analyzer provide useful alternatives to GAT in patients with abnormal corneas, such as those who have undergone laser vision correction or keratoplasty. This article reviews the various methods of intra-ocular pressure measurement available to the clinician and the ways in which their utility is influenced by variations in corneal thickness and biomechanics. PMID:27014386

  18. Intra-Ocular Pressure Measurement in a Patient with a Thin, Thick or Abnormal Cornea.

    PubMed

    Clement, Colin I; Parker, Douglas G A; Goldberg, Ivan

    2016-01-01

    Accurate measurement of intra-ocular pressure is a fundamental component of the ocular examination. The most common method of measuring IOP is by Goldmann applanation tonometry, the accuracy of which is influenced by the thickness and biomechanical properties of the cornea. Algorithms devised to correct for corneal thickness to estimate IOP oversimplify the effects of corneal biomechanics. The viscous and elastic properties of the cornea influence IOP measurements in unpredictable ways, a finding borne out in studies of patients with inherently abnormal and surgically altered corneal biomechanics. Dynamic contour tonometry, rebound tonometry and the ocular response analyzer provide useful alternatives to GAT in patients with abnormal corneas, such as those who have undergone laser vision correction or keratoplasty. This article reviews the various methods of intra-ocular pressure measurement available to the clinician and the ways in which their utility is influenced by variations in corneal thickness and biomechanics. PMID:27014386

  19. Intraocular pressure, retinal vascular, and visual acuity changes during 48 hours of 10-deg head-down tilt

    NASA Technical Reports Server (NTRS)

    Mader, Thomas H.; Taylor, Gerald R.; Hunter, Norwood; Caputo, Michael; Meehan, Richard T.

    1990-01-01

    Intraocular pressures, retinal vascular diameters, and visual acuities of nine men, were repeatedly measured while the subjects were tilted 10 deg head-down for 48 h and while they were seated before (baseline), and after the tilt. An immediate increase in intraocular pressure, measured by pneumatonometer was recorded when subjects assumed the head-down position, and diurnal variations in intraocular pressures were observed for the 48 h. The initial and final head-down intraocular pressures were not significantly different. However, when subjects resumed the sitting position, intraocular pressures fell below the initial sitting values. Computer image analysis of the retinal vasculature detected a 6 percent and 2 percent reduction in the caliber of arteries and veins, respectively, as compared with sitting baseline values. No changes in visual acuity were documented during the 48 h of head-down tilt. The data suggest that the choroidal blood reservoir increases in volume over 48 h at continuous head-down position with a compensatory decrease in aqueous volume. These findings may explain intraocular pressure changes noted in astronauts during previous space missions and in studies associated with change in body position.

  20. Socioeconomic status, systolic blood pressure and intraocular pressure: the Tanjong Pagar Study

    PubMed Central

    Yip, J L Y; Aung, T; Wong, T‐Y; Machin, D; Khaw, P T; Khaw, K‐T; Seah, S; Foster, P J

    2007-01-01

    Background Lower socioeconomic status (SES) is associated with higher morbidity and mortality in many countries. Present evidence suggests that glaucoma has similar risk factors to major chronic diseases such as cardiovascular disease. This study investigates the association between SES and intraocular pressure (IOP), an important risk factor for glaucoma. Methods The Tanjong Pagar Study was a population‐based cross‐sectional survey of Chinese people aged 40–79 years, who were randomly selected from the Singapore electoral register. Of the 2000 people selected, 1717 were considered eligible and 1090 were examined in clinic and included in the present study. IOP was measured using applanation tonometry. SES was assessed using a standardised questionnaire; education and income were used as the main explanatory variables. The effect of systolic blood pressure (SBP) was also examined. Results Participants with lower levels of education and income had higher mean IOP (both p<0.01). These associations remained after adjusting for age and central corneal thickness, a strong independent predictor. SBP was strongly associated with both SES and IOP (both p<0.01). Adjusting for SBP attenuated the association between SES and IOP. Conclusion Participants with lower education and income have a higher mean IOP. This effect may be mediated, in part, by an association of education and income with SBP. This is the first study to suggest that there is a social gradient in the distribution of the only major modifiable risk factor for glaucoma. Increasing similarities exist between the causation models of chronic diseases and that of glaucoma. PMID:16928704

  1. Sustained intraocular pressure elevation after intravitreal injection of bevacizumab and ranibizumab associated with trabeculitis.

    PubMed

    Sniegowski, Matthew; Mandava, Naresh; Kahook, Malik Y

    2010-01-01

    Anti-vascular endothelial growth factor agents are frequently used to treat a variety of ocular neovascular diseases. While agents like bevacizumab and ranibizumab appear to be safe and effective, there have been reports of severe intraocular inflammation as well as sustained elevation of intraocular pressure (IOP) after single or multiple intravitreal injections of these protein-based therapeutics. The true mechanism leading to inflammation and/or sustained spikes in IOP remains unknown. We report a patient with sustained IOP elevation and kerato-precipitates on the trabecular meshwork after multiple injections of both bevacizumab and ranibizumab. We propose that monomer antibodies, aggregated proteins, or other high molecular weight molecules might lead to inflammation in the trabecular meshwork and subsequent elevation in IOP. PMID:20871754

  2. Real-time visualization of oxygen partial pressures in straight channels of running polymer electrolyte fuel cell with water plugging

    NASA Astrophysics Data System (ADS)

    Nagase, Katsuya; Suga, Takeo; Nagumo, Yuzo; Uchida, Makoto; Inukai, Junji; Nishide, Hiroyuki; Watanabe, Masahiro

    2015-01-01

    Visualization inside polymer electrolyte fuel cells (PEFCs) for elucidating the reaction distributions is expected to improve the performance, durability, and stability. An oxygen-sensitive film of a luminescent porphyrin was used to visualize the oxygen partial pressures in five straight gas-flow channels of a running PEFC with liquid-water blockages formed at the end of the channels. The blockage greatly lowered and unstabilized the cell voltage. The oxygen partial pressure decreased nearly to 0 kPa in the blocked channel. With a water blockage in a channel, the oxygen partial pressures in the adjacent channels were lowered due to an extra demand of oxygen consumption. When the number of the blocked channels increased, the oxygen partial pressure in the unblocked channels became much lowered. When the water blockages disappeared, the oxygen partial pressures quickly returned to the values before plugging. The influence of the cross flows of air through the gas diffusion layers in straight channels was much smaller than that in serpentine flow channels.

  3. A time-delay calibrated method for cornea hysteresis and intraocular pressure measurement

    NASA Astrophysics Data System (ADS)

    Wang, Kuo-Jen; Tsai, Che-Liang; Wang, Wai; Hsu, Long; Hsu, Ken-Yuh

    2016-04-01

    The presence of cornea hysteresis (CH) in characterizing the intraocular pressure (IOP) of a human eye deteriorates the accuracy of IOP. To suppress CH, the pressure gauge of a tonometer must be located as close as possible to the cornea. However, this arrangement is unpractical because appropriate working distance to the cornea is required. In this paper, a time-delay calibrated (TDC) method is proposed to counteract the undesired effect of CH in characterizing the IOP. Employing this TDC method, the CH approaches to zero for most eyes measured.

  4. Modeling and Real-Time Process Monitoring of Organometallic Chemical Vapor Deposition of III-V Phosphides and Nitrides at Low and High Pressure

    NASA Technical Reports Server (NTRS)

    Bachmann, K. J.; Cardelino, B. H.; Moore, C. E.; Cardelino, C. A.; Sukidi, N.; McCall, S.

    1999-01-01

    The purpose of this paper is to review modeling and real-time monitoring by robust methods of reflectance spectroscopy of organometallic chemical vapor deposition (OMCVD) processes in extreme regimes of pressure. The merits of p-polarized reflectance spectroscopy under the conditions of chemical beam epitaxy (CBE) and of internal transmission spectroscopy and principal angle spectroscopy at high pressure are assessed. In order to extend OMCVD to materials that exhibit large thermal decomposition pressure at their optimum growth temperature we have designed and built a differentially-pressure-controlled (DCP) OMCVD reactor for use at pressures greater than or equal to 6 atm. We also describe a compact hard-shell (CHS) reactor for extending the pressure range to 100 atm. At such very high pressure the decomposition of source vapors occurs in the vapor phase, and is coupled to flow dynamics and transport. Rate constants for homogeneous gas phase reactions can be predicted based on a combination of first principles and semi-empirical calculations. The pressure dependence of unimolecular rate constants is described by RRKM theory, but requires variational and anharmonicity corrections not included in presently available calculations with the exception of ammonia decomposition. Commercial codes that include chemical reactions and transport exist, but do not adequately cover at present the kinetics of heteroepitaxial crystal growth.

  5. Self-Powered High-Resolution and Pressure-Sensitive Triboelectric Sensor Matrix for Real-Time Tactile Mapping.

    PubMed

    Wang, Xiandi; Zhang, Hanlu; Dong, Lin; Han, Xun; Du, Weiming; Zhai, Junyi; Pan, Caofeng; Wang, Zhong Lin

    2016-04-20

    A triboelectric sensor matrix (TESM) can accurately track and map 2D tactile sensing. A self-powered, high-resolution, pressure-sensitive, flexible and durable TESM with 16 × 16 pixels is fabricated for the fast detection of single-point and multi-point touching. Using cross-locating technology, a cross-type TESM with 32 × 20 pixels is developed for more rapid tactile mapping, which significantly reduces the addressing lines from m × n to m + n.

  6. Prostaglandin E2-Glyceryl Ester: In Vivo Evidence for a Distinct Pharmacological Identity from Intraocular Pressure Studies.

    PubMed

    Woodward, David F; Poloso, Neil J; Wang, Jenny W

    2016-08-01

    Prostaglandin E2 (PGE2)-2-glyceryl ester is a cyclo-oxygenase 2 product of the endocannabinoid 2-arachidonyl glycerol. It is claimed as pharmacologically novel, but this is complicated by rapid and irreversible isomerization to the 1(3) ester. For ocular studies, enzymatic hydrolysis of the ester moiety creates an additional complication. PG-glyceryl esters were stabilized to isomerization and hydrolysis by replacing the noncarbonyl O with NH, to form the serinolamide and propanediolamide as stable analogs of PG-2-glyceryl and PG-2-1(3) glyceryl esters, respectively. Intraocular pressure was measured in conscious dogs and conscious laser-induced ocular hypertensive monkeys. Pharmacological studies involved stable transfectants for each of the human recombinant prostanoid receptors and the isolated feline iris for prostamide activity. PGE2-serinolamide and PGE2- propanediolamide were essentially inactive at all receptors except the EP3 receptor (EC50, ∼500 nM). This obliged elucidation of EP3 receptor involvement in the intraocular pressure response to these PGE2-glycyerl ester analogs. Since the EP3 receptor agonists sulprostone and GR 63799 did not lower monkey intraocular pressure, a role for EP3 receptors in mediating the effects of PGE2-serinolamide and PGE2-propanediolamide is not indicated. PGE2-glyceryl ester (0.01% and 0.1%) substantially lowered intraocular pressure in monkeys. PGE2-propanediolamide was more efficacious than PGE2-serinolamide in lowering intraocular pressure in monkey eyes, but both appeared equieffective in dog eyes. PGE2-serinolamide dose-dependently (0.01- 0.1%) lowered intraocular pressure in both species, but PGF2 α-serinolamide was inactive. In conclusion, stable PGE2-glyceryl ester analogs lowered intraocular pressure. These findings are consistent with the presence of a PGE2-glyceryl ester-specific recognition site in the eye. PMID:27217589

  7. Real-time analysis of polyaromatic hydrocarbons in flames using atmospheric pressure ionization and tandem mass spectrometry

    SciTech Connect

    Sunner, J.; Gahm, K.H.; Ikonomou, M.; Kebarle, P.

    1988-08-01

    The use of Atmospheric Pressure Ionization followed by tandem mass spectrometry (API/MS/MS) for the analysis of flame gases was demonstrated. The hot flame gases from a methane/air laminar diffusion flame were sampled by rapid turbulent mixing with cold nitrogen gas, in a molar ratio of ca. 1 : 10. After 3 ms the gases underwent an additional dilution by a factor of 20 in synthetic air. The gas mixture was ionized by a corona discharge at atmospheric pressure. Subsequent chemical ionization reactions ionize mainly the polyaromatic hydrocarbons, PAHs. The PAH ions were analyzed in a triple quadrupole mass spectrometer. A sequence of PAH ions started with the perinaphthenyl cation, C/sub 13/H/sub 9//sup +/, and extended up to protonated coronene, C/sub 24/H/sub 13//sup +/, and beyond. That the observed ions were indeed protonated PAH molecules was confirmed by comparing the collision-induced dissociation spectra in the MS/MS mode with those of authentic samples. It is argued that most of the ions originate from PAHs that have substituents attached to the polyaromatic skeleton. The identities of the substituents could, however, not be determined. By rapid turbulent mixing of the flame gases with air, the PAHs were partially oxidized. The high mass region of the API spectrum was then dominated by a sequence of singly oxygenated PAHs.

  8. Real-time observation of the dry oxidation of the Si (100) surface with ambient pressure x-ray photoelectron spectroscopy

    SciTech Connect

    Enta, Y.; Mun, B.S.; Rossi, M.; Ross Jr, P.N.; Hussain, Zahid; Fadley, C.S.; Lee, K.-S.; Kim, S.-K.

    2007-09-20

    We have applied ambient-pressure x-ray photoelectron spectroscopy with Si 2p chemical shifts to study the real-time dry oxidation of Si(100), using pressures in the range of 0.01-1 Torr and temperatures of 300-530 oC, and examining the oxide thickness range from 0 to ~;;25 Angstrom. The oxidation rate is initially very high (with rates of up to ~;;225 Angstrom/h) and then, after a certain initial thickness of the oxide in the range of 6-22 Angstrom is formed, decreases to a slow state (with rates of ~;;1.5-4.0 Angstrom/h). Neither the rapid nor the slow regime is explained by the standard Deal-Grove model for Si oxidation.

  9. Tracking Ocean Gravity Waves in Real-time: Highlights of Bottom Pressure Data Recorded on Ocean Networks Canada's NEPTUNE observatory

    NASA Astrophysics Data System (ADS)

    Heesemann, Martin; Mihaly, Steve; Gemmrich, Johannes; Davis, Earl; Thomson, Richard; Dewey, Richard

    2016-04-01

    Ocean Networks Canada operates two cabled ocean observatories off Vancouver Island on Canada's west coast. The regional NEPTUNE observatory spans the entire Juan de Fuca tectonic plate from the coast across the subduction zone to the hydrothermally active Endeavour Segment of the Juan de Fuca Ridge Segment while the VENUS observatory focuses on coastal processes. Both observatories collect data on physical, chemical, biological, and geological aspects of the ocean over long time periods, supporting research on complex earth processes. High-precision bottom pressure recorders (BPR) deployed on the NEPTUNE observatory are capable of detecting a wide range of phenomena related to sea level variations. The observatory BPRs provide observations of nano-resolution (with respect to full scale of the instrument) pressure variations which correspond to sub-millimeter scale surface water displacements in several kilometers of water. Detected signals include tides, tsunamis, infragravity waves, swell, wave-induced microseisms, storm surge, and seismic signals. Spectral analysis reveals many of these phenomena with periods ranging from a few seconds to many hours. Dispersion patterns from distant swells are prominent in the swell and microseism bands. By comparing the difference of arrival times between longer period waves, which arrive first, and shorter period waves we can estimate the distance the swells travelled since they were generated. Using this information, swell can be tracked back to specific storms across the Pacific. The presentation will high-light some examples of the mentioned phenomena in the continuous time-series that in some instances are more than seven years long.

  10. A Circadian and Cardiac Intraocular Pressure Sensor for Smart Implantable Lens.

    PubMed

    Donida, Achille; Di Dato, Giuseppe; Cunzolo, Paolo; Sala, Marco; Piffaretti, Filippo; Orsatti, Paolo; Barrettino, Diego

    2015-12-01

    This paper presents a new system to measure the Intraocular Pressure (IOP) with very high accuracy (0.036 mbar) used for monitoring glaucoma. The system not only monitors the daily variation of the IOP (circadian IOP), but also allows to perform an spectral analysis of the pressure signal generated by the heartbeat (cardiac IOP). The system comprises a piezoresistive pressure sensor, an application-specific integrated circuit (ASIC) to read out the sensor data and an external reader installed on customized glasses. The ASIC readout electronics combines chopping modulation with correlated double sampling (CDS) in order to eliminate both the amplifier offset and the chopper ripple at the sampling frequency. In addition, programmable current sources are used to compensate for the atmospheric pressure ( 800-1200 mbar ) and the circadian component (± 7 mbar) thus allowing to read out the very weak cardiac signals (± 1.6 mbar) with a maximum accuracy of 0.036 mbar.

  11. Experimental Tibetan monkey domestication and its application for intraocular pressure measurement

    PubMed Central

    Yi, Yong; Zeng, Tao; Zhou, Liang; Cai, Su-Ping; Yin, Yan; Wang, Yun; Cao, Xu; Xu, Yue-Zhong; Wang, Hong-Xing; Liu, Xu-Yang

    2012-01-01

    AIM To train Tibetan monkey (Macaca thibetana) for intraocular pressure (IOP) measurement in conscious state and obtain normal IOP in conscious Tibetan Macaque. METHODS The training was based on award-conditioned behavior. Food stimulation and human-animal interaction were used in this training. RESULTS Trained Tibetan monkeys calmly accepted IOP measurement by the TonoVet® rebound tonometer without sedation or anesthesia and their IOP values were similar to other primates. CONCLUSION Human-cultivated Thibetan monkeys are tamable, and can be used for biomedical research such as ophthalmic research without anesthesia. PMID:22773972

  12. Abnormal increase of intraocular pressure in fellow eye after severe ocular trauma

    PubMed Central

    Vaajanen, Anu; Tuulonen, Anja

    2016-01-01

    Abstract Background: An ocular injury can lead to secondary glaucoma in the traumatized eye in 3% to 20% of cases. Literature on the risk of developing elevated intraocular pressure in the nontraumatized fellow eye is scant. Clinicians treating ocular traumas should also bear in mind sympathetic ophthalmia, a rare bilateral granulomatous panuveitis following accidental or surgical trauma to 1 eye. Case report: We report a case of high-pressure glaucoma of the fellow eye without any signs of uveitis. The left eye of a 24-year-old man was injured in an inadvertent movement during a free-time table-tennis match. The eye was severely crushed, leading to blindness. His right eye developed medically uncontrolled high-pressure glaucoma only 1 month after the injury. Conclusion: To the best of our knowledge, there are no previous reports of post-traumatic glaucoma in the nontraumatized eye after open-globe injury. PMID:27495058

  13. A new real-time method for detecting the effect of fentanyl using the preoperative pressure pain threshold and Narcotrend index: a randomized study in female surgery patients.

    PubMed

    Duan, Guangyou; Guo, Shanna; Zhan, Huiming; Qi, Dongmei; Zhang, Yuhao; Zhang, Xianwei

    2015-01-01

    Individual variability in the effects of opioid analgesics such as fentanyl remains a major challenge for tailored pharmacological treatment including postoperative analgesia. This study aimed to establish a new real-time method for detecting the effects of fentanyl and their individual differences in the preoperative period, using the pressure pain threshold (PPT) and Narcotrend index (NTI) test.Eighty women undergoing elective surgery under general anesthesia were enrolled in this randomized, double-blinded, placebo-controlled study to receive either intravenous fentanyl (Group F) or saline (Group S). Before (T1) and 5 (T2) and 10 min (T3) after intravenous injection, the PPT, NTI, respiratory rate, heart rate, blood pressure, and pulse oxygen saturation were measured. The initial time at which the Narcotrend index showed a decline was also recorded.In total, 40 patients in Group S and 38 patients in Group F were included in the final analysis. At 5 min and 10 min after intravenous fentanyl administration, the analgesic effect was determined by measuring the PPT, which was significantly increased (P < 0.001), and the sedative effect was detected using the NTI, which was significantly decreased (P < 0.001). The distribution of percentage changes of the PPT and NTI showed individual differences. At T2 and T3, the absolute changes in NTI and PPT were positively correlated (r = 0.444 at T2, P = 0.005; r = 0.332 at T3, P = 0.042).Through the PPT and NTI, it was feasible to easily detect the effects of fentanyl and their individual differences in real time before induction of anesthesia in the operation room. This method could potentially be applied to preoperatively determine patients' sensitivity to fentanyl.

  14. Real time psychrometric data collection

    SciTech Connect

    McDaniel, K.H.

    1996-12-31

    Eight Mine Weather Stations (MWS) installed at the Waste Isolation Pilot Plant (WIPP) to monitor the underground ventilation system are helping to simulate real-time ventilation scenarios. Seasonal weather extremes can result in variations of Natural Ventilation Pressure (NVP) which can significantly effect the ventilation system. The eight MWS(s) (which previously collected and stored temperature, barometric pressure and relative humidity data for subsequent NVP calculations) were upgraded to provide continuous real-time data to the site wide Central monitoring System. This data can now be utilized by the ventilation engineer to create realtime ventilation simulations and trends which assist in the prediction and mitigation of NVP and psychrometric related events.

  15. The effects of intravenous alfaxalone with and without premedication on intraocular pressure in healthy dogs.

    PubMed

    Bauer, Bianca S; Ambros, Barbara

    2016-04-01

    The objective of this study was to investigate the effects of intravenous alfaxalone with and without premedication on intraocular pressure (IOP) in healthy dogs. Thirty-three dogs were randomized to receive 1 of 3 treatments: acepromazine [0.03 mg/kg body weight (BW)] with butorphanol (0.2 mg/kg BW) intramuscularly (IM), followed by intravenous (IV) alfaxalone (1.5 mg/kg BW); dexmedetomidine (0.002 mg/kg BW) with hydromorphone (0.1 mg/kg BW) IM, followed by alfaxalone (1 mg/kg BW) IV; and saline 0.9% (0.02 mL/kg BW) IM, followed by alfaxalone (3 mg/kg BW) IV. Intraocular pressure (IOP) was measured at baseline, 15 min, and 30 min after premedication, after pre-oxygenation, after administration of alfaxalone, and after intubation. After induction and after intubation, the IOP was significantly increased in all groups compared to baseline. While premedication with acepromazine/butorphanol or dexmedetomidine/hydromorphone did not cause a significant increase in IOP, the risk of vomiting and the associated peak in IOP after dexmedetomidine/hydromorphone should be considered when selecting an anesthetic protocol for dogs with poor tolerance for transient increases in IOP. PMID:27127343

  16. Real-time radiography

    SciTech Connect

    Bossi, R.H.; Oien, C.T.

    1981-02-26

    Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components.

  17. Real-time sonography

    SciTech Connect

    Fleischey, A.C.; James, A.E. Jr.

    1984-01-01

    This textbook acquaints the reader with normal and pathologic anatomy as depicted on dynamic or real-time scanning. Chapters are organized by specialty, such as abdominal, urologic, or pediatric. The text is illustrated with still-frame images and line drawings. The drawings show important areas of interest and provide graphic notation as to where and in what orientation the scan was obtained.

  18. Reaction of a phospholipid monolayer with gas-phase ozone at the air-water interface: measurement of surface excess and surface pressure in real time.

    PubMed

    Thompson, Katherine C; Rennie, Adrian R; King, Martin D; Hardman, Samantha J O; Lucas, Claire O M; Pfrang, Christian; Hughes, Brian R; Hughes, Arwel V

    2010-11-16

    The reaction between gas-phase ozone and monolayers of the unsaturated lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, POPC, on aqueous solutions has been studied in real time using neutron reflection and surface pressure measurements. The reaction between ozone and lung surfactant, which contains POPC, leads to decreased pulmonary function, but little is known about the changes that occur to the interfacial material as a result of oxidation. The results reveal that the initial reaction of ozone with POPC leads to a rapid increase in surface pressure followed by a slow decrease to very low values. The neutron reflection measurements, performed on an isotopologue of POPC with a selectively deuterated palmitoyl strand, reveal that the reaction leads to loss of this strand from the air-water interface, suggesting either solubilization of the product lipid or degradation of the palmitoyl strand by a reactive species. Reactions of (1)H-POPC on D(2)O reveal that the headgroup region of the lipids in aqueous solution is not dramatically perturbed by the reaction of POPC monolayers with ozone supporting degradation of the palmitoyl strand rather than solubilization. The results are consistent with the reaction of ozone with the oleoyl strand of POPC at the air-water interface leading to the formation of OH radicals. The highly reactive OH radicals produced can then go on to react with the saturated palmitoyl strands leading to the formation of oxidized lipids with shorter alkyl tails.

  19. The Effect of Swimming Goggles on Intraocular Pressure and Blood Flow within the Optic Nerve Head

    PubMed Central

    Ma, Kyoung Tak; Chung, Woo Suk; Seo, Kyoung Yul; Seong, Gong Je

    2007-01-01

    Purpose Goggles are frequently worn in the sport of swimming and are designed to form a seal around the periorbital tissue orbit. The resultant pressure on the eye may have the potential to affect intraocular pressure and blood flow of the optic nerve head. This study evaluates the influence of wearing swimming goggles on intraocular pressure (IOP) and blood flow of the ocular nerve head (ONH) in normal subjects. Materials and Methods Thirty healthy participants took part in this study. The IOP of each participant was measured using a Goldmann tonometer. Measurements were taken immediately before putting on swimming goggles, at 5, 10, 30, and 60 minutes after putting on swimming goggles, and then immediately after taking off the goggles. Blood flow of the ONH was measured using the Heidelberg retinal flowmeter. Results The average IOP before, during and after wearing the swimming goggles were 11.88 ± 2.82 mmHg, 14.20 ± 2.81mmHg and 11.78 ± 2.89 mmHg, respectively. The IOP increased immediately after putting on the goggles (p < 0.05) and then returned to normal values immediately after removal (p > 0.05). Blood flow of the ONH was 336.60 ± 89.07 Arbitrary Units (AU) before and 319.18 ± 96.02 AU after the goggles were worn (p < 0.05). Conclusion A small but significant IOP elevation was observed immediately after the swimming goggles were put on. This elevated IOP was maintained while the goggles were kept on, and then returned to normal levels as soon as they were taken off. Blood flow of the ONH did not change significantly throughout the experiment. These facts should be considered for safety concerns, especially in advanced glaucoma patients. PMID:17963338

  20. Real-Time PCR

    NASA Astrophysics Data System (ADS)

    Evrard, A.; Boulle, N.; Lutfalla, G. S.

    Over the past few years there has been a considerable development of DNA amplification by polymerase chain reaction (PCR), and real-time PCR has now superseded conventional PCR techniques in many areas, e.g., the quantification of nucleic acids and genotyping. This new approach is based on the detection and quantification of a fluorescent signal proportional to the amount of amplicons generated by PCR. Real-time detection is achieved by coupling a thermocycler with a fluorimeter. This chapter discusses the general principles of quantitative real-time PCR, the different steps involved in implementing the technique, and some examples of applications in medicine. The polymerase chain reaction (PCR) provides a way of obtaining a large number of copies of a double-stranded DNA fragment of known sequence. This DNA amplification technique, developed in 1985 by K. Mullis (Cetus Corporation), saw a spectacular development over the space of a few years, revolutionising the methods used up to then in molecular biology. Indeed, PCR has many applications, such as the detection of small amounts of DNA, cloning, and quantitative analysis (assaying), each of which will be discussed further below.

  1. The effect of long-term use of intranasal steroids on intraocular pressure.

    PubMed

    Şimşek, Ali; Bayraktar, Cem; Doğan, Sedat; Karataş, Mehmet; Sarıkaya, Yasin

    2016-01-01

    Long-term use of topical nasal steroids (especially older generation steroids) has been shown to elevate intraocular pressure (IOP), but newer intranasal steroids are thought to have a minimal effect on IOP because of their low bioavailability. This study aimed to investigate alterations in IOP with two commonly used intranasal steroids for a 6-month period of time. One-hundred allergic rhinitis patients, divided equally into two groups, used mometasone furoate and fluticasone furoate intranasal steroids for 6 months. IOPs were measured before treatment and repeated at the 3rd, 6th, 12th, and 24th weeks of treatment. The IOPs of the groups were then compared. No statistically significant alteration was observed between the groups during the treatment time period. It was found that new generation intranasal steroids can be used safely, and there may not be an increased risk of IOP elevation in prolonged use in normal healthy people. PMID:27354761

  2. Proper outcome measurements regarding glaucoma: the inadequacy of using intraocular pressure alone.

    PubMed

    Spaeth, G L

    1996-01-01

    Physicians typically assess glaucoma treatment in terms of the effect on intraocular pressure (IOP). However, it is inappropriate to use IOP as the sole outcome measure for the management of glaucoma for several reasons: a) it is a precursor of disease, but not the disease itself. b) Most often, it is not the only factor responsible for glaucomatous damage. c) It suggests, wrongly, that IOP should be maximally lowered in all glaucoma patients. d) We are beginning to be able to assess more accurately other signs, not just precursors, of glaucomatous damage itself, most importantly, optic disc damage and visual field loss. Even though these signs are far more valuable than IOP in assessing the outcome of treatment, they, too, nevertheless, are ultimately subordinate to the effect of treatment on the patient's quality of life. PMID:8823579

  3. Ocular health assessment, tear production, and intraocular pressure in the Andros Island iguana (Cyclura cychlura cychlura).

    PubMed

    Wojick, Kimberlee B; Naples, Lisa M; Knapp, Charles R

    2013-03-01

    The purpose of this study was to assess the ocular health of a wild population of Andros Island iguanas (Cyclura cychlura cychlura) and determine reference values for tear production and intraocular pressure (IOP) for this species. Fifty-two iguanas, 20 males and 32 females, ranging in size from 11.1- to 51.0-cm snout-to-vent length (SVL), were included in the sample set, with measurements obtained from each eye. No abnormalities were found on ophthalmic examination, with the exception of mild, focal chemosis in one individual and periocular ticks in 52% of iguanas. Tear production was measured using the phenol red thread test, and IOP was measured using the TonoVet rebound tonometer set on the P (undefined species) setting. No significant difference was found between males and females for either measurement. No significant difference was found between right and left eyes for intraocular pressure; however, a significant difference was found between eyes for tear production values. The mean (+/- SD) of IOP in the left and right eyes were 4.77 +/- 1.88 mm Hg and 5.12 +/- 2.52 mm Hg, respectively, with a range of 1-11 mm Hg. The mean (+/- SD) of tear production in the left and right eyes were 10.63 +/- 6.89 mm/15 sec (range 1-28 mm/15 sec) and 12.44 +/- 7.52 mm/15 sec (range 1-23 mm/15 sec), respectively. A positive correlation was found between SVL and all ocular parameters measured. This study provides an assessment of ocular health, as well as baseline values for IOP and tear production, in the Andros Island iguana. PMID:23505711

  4. Exome Array Analysis Identifies CAV1/CAV2 as a Susceptibility Locus for Intraocular Pressure

    PubMed Central

    Chen, Fei; Klein, Alison P.; Klein, Barbara E. K.; Lee, Kristine E.; Truitt, Barbara; Klein, Ronald; Iyengar, Sudha K.; Duggal, Priya

    2015-01-01

    Purpose. Intraocular pressure (IOP) is an important clinical parameter in the evaluation of ocular health. Elevated IOP is a major risk factor for primary open-angle glaucoma (POAG). The goal of this study was to identify rare and less common variants that influence IOP. Methods. We performed an exome array analysis in a subset of 1660 individuals from a population-based cohort, the Beaver Dam Eye Study. Associations with IOP were tested on 45,849 single nucleotide variants and 12,390 autosomal genes across the genome. Results. Intraocular pressure was suggestively associated with novel variants located in FAR2 at 12p11.22 (rs4931170, P = 1.2 × 10−5), in GGA3 at 17q25.1 (rs52809447, P = 6.7 × 10−5), and in PKDREJ at 22q13.31 (rs7291444, P = 7.4 × 10−5). Gene-based analysis found suggestive associations between IOP and the genes HAP1, MTBP, FREM3, and PHF12. We successfully replicated the associations with GAS7 (P = 7.4 × 10−3) for IOP, and also identified a previously reported POAG locus in the CAV1/CAV2 region to be associated with IOP (P = 3.3 × 10−3). This association was confirmed in a meta-analysis with three published genome-wide association studies (Pcombined = 4.0 × 10−11). Conclusions. Our results suggest that novel genetic variants and genes with multiple, less common variants may play a role in the control of IOP. The implication of the caveolin genes, CAV1/CAV2, as a common genetic factor influencing both IOP variations and POAG may provide new insights of the underlying mechanism leading to glaucoma and glaucomatous visual field loss. PMID:25525164

  5. Glaucoma Surgery Calculator: Limited Additive Effect of Phacoemulsification on Intraocular Pressure in Ab Interno Trabeculectomy

    PubMed Central

    Schuman, Joel S.; Brown, Eric N.

    2016-01-01

    Purpose To compare intraocular pressure (IOP) reduction and to develop a predictive surgery calculator based on the results between trabectome-mediated ab interno trabeculectomy in pseudophakic patients versus phacoemulsification combined with trabectome-mediated ab interno trabeculectomy in phakic patients. Methods This observational surgical cohort study analyzed pseudophakic patients who received trabectome-mediated ab interno trabeculectomy (AIT) or phacoemulsification combined with AIT (phaco-AIT). Follow up for less than 12 months or neovascular glaucoma led to exclusion. Missing data was imputed by generating 5 similar but non-identical datasets. Groups were matched using Coarsened Exact Matching based on age, gender, type of glaucoma, race, preoperative number of glaucoma medications and baseline intraocular pressure (IOP). Linear regression was used to examine the outcome measures consisting of IOP and medications. Results Of 949 cases, 587 were included consisting of 235 AIT and 352 phaco-AIT. Baseline IOP between groups was statistically significant (p≤0.01) in linear regression models and was minimized after Coarsened Exact Matching. An increment of 1 mmHg in baseline IOP was associated with a 0.73±0.03 mmHg IOP reduction. Phaco-AIT had an IOP reduction that was only 0.73±0.32 mmHg greater than that of AIT. The resulting calculator to determine IOP reduction consisted of the formula -13.54+0.73 × (phacoemulsification yes:1, no:0) + 0.73 × (baseline IOP) + 0.59 × (secondary open angle glaucoma yes:1, no:0) + 0.03 × (age) + 0.09 × (medications). Conclusions This predictive calculator for minimally invasive glaucoma surgery can assist clinical decision making. Only a small additional IOP reduction was observed when phacoemulsification was added to AIT. Patients with a higher baseline IOP had a greater IOP reduction. PMID:27077914

  6. Short-Term Moderately Elevated Intraocular Pressure Is Associated With Elevated Scotopic Electroretinogram Responses

    PubMed Central

    Choh, Vivian; Gurdita, Akshay; Tan, Bingyao; Prasad, Ratna C.; Bizheva, Kostadinka; Joos, Karen M.

    2016-01-01

    Purpose Moderately elevated intraocular pressure (IOP) is a risk factor for open-angle glaucoma. Some patients suffer glaucoma despite clinically measured normal IOPs. Fluctuations in IOP may have a significant role since IOPs are higher during sleep and inversion activities. Controlled transient elevations of IOPs in rats over time lead to optic nerve structural changes that are similar to the early changes observed in constant chronic models of glaucoma. Because early intervention decreases glaucoma progression, this study was done to determine if early physiological changes to the retina could be detected with noninvasive electrophysiological and optical imaging tests during moderately elevated IOP. Methods Intraocular pressures were raised to moderately high levels (35 mm Hg) in one eye of Sprague-Dawley rats while the other (control) eye was untreated. One group of rats underwent scotopic threshold response (STR) and electroretinogram (ERG) testing, while another 3 groups underwent optical coherence tomography (OCT) imaging, Western blot, or histologic evaluation. Results The amplitudes of the STR and ERG responses in eyes with moderately elevated IOPs were enhanced compared to the values before IOP elevation, and compared to untreated contralateral eyes. Structural changes to the optic nerve also occurred during IOP elevation. Conclusions Although ischemic IOP elevations are well-known to globally reduce components of the scotopic ERG, acute elevation in rats to levels often observed in untreated glaucoma patients caused an increase in these parameters. Further exploration of these phenomena may be helpful in better understanding the mechanisms mediating early retinal changes during fluctuating or chronically elevated IOP. PMID:27100161

  7. Intraoperative testing of opening and closing pressure predicts risk of low intraocular pressure after Ahmed glaucoma valve implantation

    PubMed Central

    Bochmann, F; Kipfer, A; Tarantino, J; Kaufmann, C; Bachmann, L; Thiel, M

    2014-01-01

    Purpose The aim of this study was to assess whether intraoperative testing of silicone Ahmed glaucoma valves (AGVs) would identify valves with an increased risk of low postoperative intraocular pressure (IOP). Methods In 30 consecutive cases of glaucoma surgery with AGV implantation, after priming the AGV, we intraoperatively measured the opening pressure A, closing pressure B, and re-opening pressure C using the active infusion pump of a phako-machine. IOP was checked postoperatively on the same day. Low IOP was defined as <5 mm Hg. Intraoperatively measured pressure characteristics of the valve function were analysed for their ability to predict postoperative IOP outcomes. Results Opening A, closing B, and re-opening C pressures (mean, (SD)) were 18.4 (5.1), 8.3 (4.7), and 11.7 (4.8)mm Hg, respectively. Ten patients (33.3%) had low IOP. An opening pressure of ≤18 mm Hg predicted low postoperative IOP with a sensitivity (10/10) of 100% (95% CI, 69.2–100) and a specificity (13/20) of 65.0% (95% CI, 40.8–84.6). Conclusions AGVs have a high variability of opening, closing, and re-opening pressures. An opening pressure of ≤18 mm Hg, a closing pressure of ≤10 mm Hg, or a re-opening pressure of ≤11 mm Hg identified all patients with low postoperative IOP. PMID:25060848

  8. Real time Faraday spectrometer

    DOEpatents

    Smith, Jr., Tommy E.; Struve, Kenneth W.; Colella, Nicholas J.

    1991-01-01

    This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

  9. Real time SAR processing

    NASA Technical Reports Server (NTRS)

    Premkumar, A. B.; Purviance, J. E.

    1990-01-01

    A simplified model for the SAR imaging problem is presented. The model is based on the geometry of the SAR system. Using this model an expression for the entire phase history of the received SAR signal is formulated. From the phase history, it is shown that the range and the azimuth coordinates for a point target image can be obtained by processing the phase information during the intrapulse and interpulse periods respectively. An architecture for a VLSI implementation for the SAR signal processor is presented which generates images in real time. The architecture uses a small number of chips, a new correlation processor, and an efficient azimuth correlation process.

  10. Real-Time Revolution?

    PubMed

    Berlin, Joey

    2016-03-01

    Austin Regional Clinic (ARC) physicians and officials know patient feedback is important, but getting patients to provide it can be a challenge. A pilot program of a new, real-time feedback system provided ARC patients a high-tech convenience previous attempts lacked and produced participation numbers dwarfing those past efforts. ARC's initial results with the system, in which patients answer five to seven questions on a computer tablet and can leave free-text comments, were so successful the clinic is already planning to expand it to all of its locations by the end of June.

  11. A capacitor-based sensor and a contact lens sensing system for intraocular pressure monitoring

    NASA Astrophysics Data System (ADS)

    Chiou, Jin-Chern; Huang, Yu-Chieh; Yeh, Guan-Ting

    2016-01-01

    This study proposes a capacitor-based sensor on a soft contact lens for the measurement of intraocular pressure (IOP). The sensor was designed and fabricated via microelectromechanical system fabrication technologies. The soft contact lens is designed to be worn on a cornea such that the curvature of the contact lens corresponds substantially to that of the cornea. In addition, the contact lens was fabricated via a cast-molding method using poly-2-hydroxyethyl methacrylate to achieve a lens with high oxygen permeability, which can be worn comfortably for a long time. An IOP sensor prototype was implemented, which exhibited 1.2239 pF mmHg-1 (13,171 ppm mmHg-1) sensitivity during measurements of an artificial anterior chamber at pressures between 18 and 30 mmHg. The results indicate that the developed capacitor-based IOP sensor exhibited high stability and reproducibility in a series of measurements performed under various pressures. The capacitance of the proposed IOP sensor can successfully be converted into a digital value via a capacitor-to-digital converter and be transmitted via a commercial wireless telemetry system in this study.

  12. A wireless intraocular pressure monitoring device with a solder-filled microchannel antenna

    NASA Astrophysics Data System (ADS)

    Varel, Çağdaş; Shih, Yi-Chun; Otis, Brian P.; Shen, Tueng S.; Böhringer, Karl F.

    2014-04-01

    This paper presents the prototype of an intraocular pressure sensor as a major step toward building a device that can be permanently implanted during cataract surgery. The implantation will proceed through an incision of 2-3 mm using an injector, during which the complete device must be folded into a cross-section of 2 mm × 1 mm. The device uses radio frequency (RF) for wireless power and data transfer. The prototype includes an antenna, an RF chip and a pressure sensor assembled on a printed circuit board with several circuit components used for testing and calibration. The antenna is fabricated and integrated with the circuit using a fabrication method employing solder-filled microchannels embedded in an elastomer. The monitoring device is powered at 2.716 GHz from a distance of 1-2 cm. The prototype has undergone electrical and mechanical tests for antenna and sensor performance. The flexible antenna can withstand a stress of 33.4 kPa without any electrical disconnection. It did not show a significant increase in electrical resistance after 50 bending cycles with a maximum applied stress of 116 kPa. Transmitted pressure data shows an averaged sensitivity of 16.66 Hz (mm-Hg)-1.

  13. Real-time Measurement of Secondary Organic Aerosols From The Photo-oxidation of Toluene Using Atmospheric Pressure Chemical Ionisation Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Collin, F.; Arias, M. C.; Merritt, J. V.; Hastie, D. R.

    A system has been developed to study the chemical composition of secondary or- ganic aerosol (SOA) from the photo-oxidation of hydrocarbons using real-time atmo- spheric pressure chemical ionisation triple quadrupole mass spectrometry (APCI/MS- MS) analysis. To complement existing work with a smog chamber, a two-litre dynamic reaction cell has been built. This has a residence time of around two minutes (instead of several hours for smog chamber experiments), thus permitting on-line analysis. Sample gases are introduced into the air stream and irradiated by a 1000 W xenon arc lamp. Af- ter dilution, some of the mixture from the reaction cell is introduced in the MS ion source via a heated probe, with the particle number density being determined by a condensation nucleus counter on the remainder. The focus so far has been on SOA from the photo-oxidation of toluene by HO radicals in presence of NO, with the HO radicals being generated by the photolysis of Isopy- lNitrite (IPN). Prior to performing analyses on the SOA, target compounds (detected in the particulate phase in other studies) were selected and three ions designated to make a fingerprint for each compound. Finally, by using either a denuder, a granu- lar bed diffusion battery or a filter, both gas and particulate phases have been studied independently and compared. Preliminary results show that a number of target compounds, such as methylglyoxylic acid, benzaldehyde or cresol, have been detected in both gas and particulate phases. Most of these compounds appear to be present mainly in the gas phase. An exhaustive identification of organic compounds is a part of the on-going work.

  14. Real time automated inspection

    DOEpatents

    Fant, K.M.; Fundakowski, R.A.; Levitt, T.S.; Overland, J.E.; Suresh, B.R.; Ulrich, F.W.

    1985-05-21

    A method and apparatus are described relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections. 43 figs.

  15. Real time automated inspection

    DOEpatents

    Fant, Karl M.; Fundakowski, Richard A.; Levitt, Tod S.; Overland, John E.; Suresh, Bindinganavle R.; Ulrich, Franz W.

    1985-01-01

    A method and apparatus relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges are segmented out by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections.

  16. Regulation of optic nerve head blood flow during combined changes in intraocular pressure and arterial blood pressure

    PubMed Central

    Boltz, Agnes; Schmidl, Doreen; Werkmeister, René M; Lasta, Michael; Kaya, Semira; Palkovits, Stefan; Told, Reinhard; Napora, Katarzyna J; Popa-Cherecheanu, Alina; Garhöfer, Gerhard; Schmetterer, Leopold

    2013-01-01

    In the choroid, there is evidence that blood flow does not only depend on ocular perfusion pressure (OPP), but also on absolute mean arterial pressure (MAP) and intraocular pressure (IOP). The present study included 40 healthy subjects to investigate whether such behavior is also found in the optic nerve head (ONH). The ONH blood flow (ONHBF) was studied using laser Doppler flowmetry during a separate increase in IOP and MAP as well as during a combined elevation. Mean arterial pressure was increased by isometric exercise and IOP by the suction method. During both, the change in ONHBF was less pronounced than the change in OPP indicating autoregulation. Correlation analysis was performed for the combined experiments after pooling all data according to IOP and MAP values. A correlation between ONHBF and MAP was found at IOPs ⩽25 mm Hg (P<0.001), but not at IOPs>25 mm Hg (P=0.79). Optic nerve head blood flow and IOP were significantly correlated (P<0.001), and ONHBF was only slightly dependent on MAP. The data of the present study indicate a complex regulation of ONHBF during combined changes in MAP and IOP. Our results may be compatible with myogenic mechanisms underlying autoregulation, and indicate better ONHBF regulation during an increase in MAP than during an increase in IOP. PMID:23921903

  17. Computational Modeling of Fluid Flow and Intra-Ocular Pressure following Glaucoma Surgery

    PubMed Central

    Gardiner, Bruce S.; Smith, David W.; Coote, Michael; Crowston, Jonathan G.

    2010-01-01

    Background Glaucoma surgery is the most effective means for lowering intraocular pressure by providing a new route for fluid to exit the eye. This new pathway is through the sclera of the eye into sub-conjunctival tissue, where a fluid filled bleb typically forms under the conjunctiva. The long-term success of the procedure relies on the capacity of the sub-conjunctival tissue to absorb the excess fluid presented to it, without generating excessive scar tissue during tissue remodeling that will shut-down fluid flow. The role of inflammatory factors that promote scarring are well researched yet little is known regarding the impact of physical forces on the healing response. Methodology To help elucidate the interplay of physical factors controlling the distribution and absorption of aqueous humor in sub-conjunctival tissue, and tissue remodeling, we have developed a computational model of fluid production in the eye and removal via the trabecular/uveoscleral pathways and the surgical pathway. This surgical pathway is then linked to a porous media computational model of a fluid bleb positioned within the sub-conjunctival tissue. The computational analysis is centered on typical functioning bleb geometry found in a human eye following glaucoma surgery. A parametric study is conducted of changes in fluid absorption by the sub-conjunctival blood vessels, changes in hydraulic conductivity due to scarring, and changes in bleb size and shape, and eye outflow facility. Conclusions This study is motivated by the fact that some blebs are known to have ‘successful’ characteristics that are generally described by clinicians as being low, diffuse and large without the formation of a distinct sub-conjunctival encapsulation. The model predictions are shown to accord with clinical observations in a number of key ways, specifically the variation of intra-ocular pressure with bleb size and shape and the correspondence between sites of predicted maximum interstitial fluid pressure

  18. Selectively bonded polymeric glaucoma drainage device for reliable regulation of intraocular pressure.

    PubMed

    Moon, Seunghwan; Im, Seongmin; An, Jaeyong; Park, Chang Ju; Kim, Hwang Gyun; Park, Sang Woo; Kim, Hyoung Ihl; Lee, Jong-Hyun

    2012-04-01

    A novel glaucoma drainage device (GDD) using a polymeric micro check valve with no reverse flow is presented for the effective regulation of intraocular pressure (IOP). A significant functional improvement was achieved by reducing the possible incidence of hypotony, as the proposed GDD only drains aqueous humor at a certain cracking pressure or higher. The device consists of three biocompatible polymer layers: a top layer (cover), an intermediate layer (membrane), and a bottom layer (base plate with a cannula). All three layers, made of soft polydimethylsiloxane (PDMS), were bonded together to realize the thin GDDs. The bottom layer was selectively coated with chromium (Cr)/gold (Au) to prevent stiction between the valve seat and the valve orifice so that the device could show enhanced reliability in operation and high yield in production. Two types of polymeric devices were fabricated; one was a glaucoma drainage device for humans (GDDH) and the other was a glaucoma drainage device for animals (GDDA). From subsequent in vitro tests, the cracking pressures were 18.33 ± 0.66 mmHg (mean ± standard deviation) for GDDH and 12.42 mmHg for GDDA, both of which were very close to the corresponding normal IOPs. From in vivo tests of GDDA, the IOP of all implanted devices was properly regulated within the target pressure (10-15 mmHg). The experimental results showed that the proposed polymeric GDD has high potential for use in the treatment of glaucoma disease in terms of its repeatability of the cracking pressure and patients' relief from post-operative discomfort. PMID:22094823

  19. Corneal biomechanical changes and intraocular pressure in patients with thyroid orbitopathy

    PubMed Central

    Pniakowska, Zofia; Klysik, Anna; Gos, Roman; Jurowski, Piotr

    2016-01-01

    AIM To determine the relevance of the objective parameters addressing the altered biomechanical properties of cornea for glaucoma monitoring in patients with mild or moderate thyroid associated orbitopathy (TAO), and in healthy individuals. METHODS Twenty-five patients with TAO (group 1) and 25 healthy adults (group 2) were included to the study. Both groups were of a similar age and the ratio women:man. For each patient, the following parameters of both eyes were measured with ocular response analyzer (ORA): corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOPg) and corneal compensated intraocular pressure (IOPcc). In both groups participating in our study, all measurements were performed within minutes to reduce the diurnal effects. RESULTS The mean age in group 1 was 56±11y and 76% were women, 24% were men. The mean age in group 2 was 64±11y and 68% were women, 32% were men. CH correlated negatively with IOPg in group 1 (r2=0.10, P<0.05). IOPg strongly correlated with IOPcc in both groups (group 1: r2=0.79, P<0.0001; group 2: r2=0.85, P<0.0001). There was positive correlation between CRF and IOPg in group 1 (r2=0.12, P<0.05) and in group 2 (r2=0.31, P<0.0001). Statistical analysis revealed no significant correlation between CRF and IOPcc in group 1 (r2=0.009, P>0.05) and also no significant correlation in group 2 (r2=0.04, P>0.05). CRF mean value in group 2 (11.51±1.72 mm Hg) was higher than in group 1 (10.85±1.45 mm Hg) (P<0.05). IOPg strongly correlated with IOPcc in both groups (group 1: r2=0.79, P<0.0001; group 2: r2=0.85, P<0.0001). There was also strong correlation between CRF and CH in both populations: group 1: (r2=0.58, P<0.0001), group 2: (r2=0.41, P<0.0001). CONCLUSION Biomechanical parameters of cornea, as quantified by CH and CRF, and measured together with IOPcc, precisely reveal glaucoma staging in TAO and thus are reliable for diagnosing and follow-up in clinical practice. PMID:27158617

  20. Effects of inner materials on the sensitivity and phase depth of wireless inductive pressure sensors for monitoring intraocular pressure

    NASA Astrophysics Data System (ADS)

    Jang, Cheol-In; Shin, Kyeong-Sik; Kim, Mi Jeung; Yun, Kwang-Seok; Park, Ki Ho; Kang, Ji Yoon; Lee, Soo Hyun

    2016-03-01

    In this research, we developed wireless, inductive, pressure sensors with high sensitivity and investigated the effects of the inner materials (copper or ferrite) on the performance of the sensors. The proposed sensor is comprised of two parts, i.e., the top and the bottom parts. The top part includes a micro coil and a capacitor for the wireless transfer of data, and the bottom part includes the inner materials and a thick or thin flexible membrane to induce changes in the inductance. An anchor is used to assemble the top and bottom parts. The behavior of the sensor with copper was based on the eddy current effect, and, as the pressure increased, its resonance frequency increased, while its phase depth decreased exponentially. The principle of the sensor with ferrite was related to the effective permeability between a ferrite and a coil, and its response was the opposite of that with copper, i.e., as the pressure increased, the resonance frequency decreased linearly, and the phase depth increased linearly. These different operational mechanisms can be explained by the changes in the equations of inductance presented in this paper. After characterizing four different types of inductive pressure sensors in ambient air, one type of inductive pressure sensor was used to monitor the intraocular pressure (IOP) of a rabbit's eye as a biomedical application. The results showed that, in the animal tests, the measured responsivity and sensitivity were 16.7 kHz/mmHg and 1340 ppm/mmHg, respectively. These data indicate that the proposed sensor is a good candidate for monitoring IOP.

  1. Real time polarimetric dehazing.

    PubMed

    Mudge, Jason; Virgen, Miguel

    2013-03-20

    Remote sensing is a rich topic due to its utility in gathering detailed accurate information from locations that are not economically feasible traveling destinations or are physically inaccessible. However, poor visibility over long path lengths is problematic for a variety of reasons. Haze induced by light scatter is one cause for poor visibility and is the focus of this article. Image haze comes about as a result of light scattering off particles and into the imaging path causing a haziness to appear on the image. Image processing using polarimetric information of light scatter can be used to mitigate image haze. An imaging polarimeter which provides the Stokes values in real time combined with a "dehazing" algorithm can automate image haze removal for instant applications. Example uses are to improve visual display providing on-the-spot detection or imbedding in an active control loop to improve viewing and tracking while on a moving platform. In addition, removing haze in this manner allows the trade space for a system operational waveband to be opened up to bands which are object matched and not necessarily restricted by scatter effects. PMID:23518739

  2. Real time analysis under EDS

    NASA Astrophysics Data System (ADS)

    Schneberk, D.

    1985-07-01

    The analysis component of the Enrichment Diagnostic System (EDS) developed for the Atomic Vapor Laser Isotope Separation Program (AVLIS) at Lawrence Livermore National Laboratory (LLNL) is described. Four different types of analysis are performed on data acquired through EDS: (1) absorption spectroscopy on laser-generated spectral lines, (2) mass spectrometer analysis, (3) general purpose waveform analysis, and (4) separation performance calculations. The information produced from this data includes: measures of particle density and velocity, partial pressures of residual gases, and overall measures of isotope enrichment. The analysis component supports a variety of real-time modeling tasks, a means for broadcasting data to other nodes, and a great degree of flexibility for tailoring computations to the exact needs of the process. A particular data base structure and program flow is common to all types of analysis. Key elements of the analysis component are: (1) a fast access data base which can configure all types of analysis, (2) a selected set of analysis routines, (3) a general purpose data manipulation and graphics package for the results of real time analysis.

  3. Real-time analysis of ambient organic aerosols using aerosol flowing atmospheric-pressure afterglow mass spectrometry (AeroFAPA-MS)

    NASA Astrophysics Data System (ADS)

    Brüggemann, Martin; Karu, Einar; Stelzer, Torsten; Hoffmann, Thorsten

    2015-04-01

    Organic aerosol accounts for a major fraction of atmospheric aerosols and has implications on the earth's climate and human health. However, due to the chemical complexity its measurement remains a major challenge for analytical instrumentation.1 Here, we present the development, characterization and application of a new soft ionization technique that allows mass spectrometric real-time detection of organic compounds in ambient aerosols. The aerosol flowing atmospheric-pressure afterglow (AeroFAPA) ion source utilizes a helium glow discharge plasma to produce excited helium species and primary reagent ions. Ionization of the analytes occurs in the afterglow region after thermal desorption and results mainly in intact molecular ions, facilitating the interpretation of the acquired mass spectra. In the past, similar approaches were used to detect pesticides, explosives or illicit drugs on a variety of surfaces.2,3 In contrast, the AeroFAPA source operates 'online' and allows the detection of organic compounds in aerosols without a prior precipitation or sampling step. To our knowledge, this is the first application of an atmospheric-pressure glow discharge ionization technique to ambient aerosol samples. We illustrate that changes in aerosol composition and concentration are detected on the time scale of seconds and in the ng-m-3 range. Additionally, the successful application of AeroFAPA-MS during a field study in a mixed forest region in Central Europe is presented. Several oxidation products of monoterpenes were clearly identified using the possibility to perform tandem MS experiments. The acquired data are in agreement with previous studies and demonstrate that AeroFAPA-MS is a suitable tool for organic aerosol analysis. Furthermore, these results reveal the potential of this technique to enable new insights into aerosol formation, growth and transformation in the atmosphere. References: 1) IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The

  4. Changes in intraocular pressure following administration of suxamethonium and endotracheal intubation: Influence of dexmedetomidine premedication

    PubMed Central

    Pal, Chandan Kumar; Ray, Manjushree; Sen, Anjana; Hajra, Bimal; Mukherjee, Dipankar; Ghanta, Anil Kumar

    2011-01-01

    Background: Use of suxamethonium is associated with an increase in intraocular pressure (IOP) and may be harmful for patients with penetrating eye injuries. The purpose of our study was to observe the efficacy of dexmedetomidine for prevention of rise in IOP associated with the administration of suxamethonium and endotracheal intubation. Methods: Sixty-six American Society of Anaesthesiologists I or II patients undergoing general anaesthesia for non-ophthalmic surgery were included in this randomized, prospective, clinical study. Patients were allocated into three groups to receive 0.4 μg/kg dexmedetomidine (group D4), 0.6 μg/kg dexmedetomidine (group D6) or normal saline (group C) over a period of 10 min before induction. IOP, heart rate and mean arterial pressure were recorded before and after the premedication, after induction, after suxamethonium injection and after endotracheal intubation. Results: Fall in IOP was observed following administration of dexmedetomidine. IOP increased in all three groups after suxamethonium injection and endotracheal intubation, but it never crossed the baseline value in group D4 as well as in group D6. Fall in mean arterial pressure was noticed after dexmedetomidine infusion, especially in the D6 group. Conclusion: Dexmedetomidine (0.6 μg/kg as well as 0.4 μg/kg body weight) effectively prevents rise of IOP associated with administration of suxamethonium and endotracheal intubation. However, dexmedetomidine 0.6 μg/kg may cause significant hypotension. Thus, dexmedetomidine 0.4 μg/kg may be preferred for prevention of rise in IOP. PMID:22223900

  5. Distribution of intraocular pressure and its determinants in an Iranian adult population

    PubMed Central

    Hashemi, Hassan; Khabazkhoob, Mehdi; Emamian, Mohammad Hassan; Shariati, Mohammad; Yekta, Abbasali; Fotouhi, Akbar

    2016-01-01

    AIM To determine the distribution of intraocular pressure (IOP) and its determinants in an Iranian population. METHODS In a cross-sectional survey, random cluster sampling was conducted from the 40-64 years old population of Shahroud, in the north of Iran. All participants had optometry and ophthalmic exams. IOP was determined using the Goldmann tonometry method and biometric components were measured. RESULTS Of the 6311 people selected for the study, 5190 (82.2%) participated. The mean age of the participants was 50.9±6.2y and 58.7% of them were female. Mean IOP was 12.87±2.27 mm Hg. In this study 0.3% of the participants had an IOP higher than 21 mm Hg. The multiple linear regression model revealed that sex (Coef=-0.30; 95% CI: -0.43 to -0.17), diabetes (Coef=0.43; 95% CI: 0.19 to 0.67), high systolic blood pressure (Coef=0.02; 95% CI: 0.01 to 0.02), high body mass index (BMI) (Coef=0.03; 95% CI: 0.01 to 0.04), higher education (Coef=0.02, 95% CI: 0.01 to 0.04), thicker central corneal thickness (Coef=0.01; 95% CI: 0.01 to 0.02), and myopic shift in spherical equivalent (Coef=-0.14; 95% CI: -0.18 to -0.10) significantly correlated with high IOP. CONCLUSION The IOP in this 40-64 years old population is low overall. In the north of Iran, average IOP is statistically significantly correlated with female sex, diabetes, higher BMI, systolic blood pressure, higher education, thicker cornea, and myopic refractive error. PMID:27588277

  6. The effects of oversize donor buttons on postoperative intraocular pressure and corneal curvature in aphakic penetrating keratoplasty.

    PubMed

    Bourne, W M; Davison, J A; O'Fallon, W M

    1982-03-01

    Forty-one consecutive aphakic corneal transplants performed by the same surgeon were studied in order to determine the effects on intraocular pressure and corneal curvature of using 8.0-mm donor buttons in 7.5-mm recipient openings. One half of the grafts had oversize donor buttons, and all were followed for 13 months. The intraocular pressure in the oversize donor group was statistically significantly less during the first five days after keratoplasty, but not subsequently. Eliminating eyes with preoperative glaucoma, more transplants in the same size donor group (P = 0.08) needed glaucoma therapy 13 months after operation. The anterior corneal curvature (mean keratometry reading) was statistically significantly greater in the oversize donor group throughout the postoperative period. Concurrently, the oversize donor group was less hyperopic after all sutures were removed. There was no difference in keratometric astigmatism or corneal thickness between the two groups. Thus, the use of 0.5-mm oversize donor tissue in aphakic corneal transplants reduced the intraocular pressure and increased the central corneal curvature after keratoplasty.

  7. Lowered intraocular pressure in a glaucoma patient after intravitreal injection of ocriplasmin

    PubMed Central

    McClintock, Michael; MacCumber, Mathew W

    2015-01-01

    We report the case of a glaucoma patient who received a single intravitreal injection of 125 µg ocriplasmin for vitreomacular traction in the right eye. The patient had bilateral advanced glaucoma and had previously undergone an implantation of an Ahmed glaucoma valve in the right eye and trabeculectomy in both eyes. The patient was using three topical ophthalmic intraocular pressure (IOP)-lowering medications on the day of injection. Baseline uncorrected Snellen visual acuity was 20/80-1 and IOP was 19 mmHg. Resolution of vitreomacular traction was achieved 1 week after injection. IOP was transiently decreased, reaching a maximum reduction of 12 mmHg below baseline at 1 month after injection, when serous choroidal effusion was also present. IOP returned to baseline levels and choroidal effusion resolved at 2 months after injection of IOP-lowering medication. Vitrectomy with epiretinal membrane and internal limiting membrane peeling, endolaser photocoagulation, and fluid–gas exchange were performed in the right eye ~3.5 months after injection to treat persistent epiretinal membrane, and presumed tractional retinal detachment. Final visual acuity was 20/50+ and IOP was 18 mmHg at 16 weeks after surgery. To our knowledge, this is the first report of IOP reduction and serous choroidal effusion after ocriplasmin injection. PMID:26604668

  8. TRPV4 regulates calcium homeostasis, cytoskeletal remodeling, conventional outflow and intraocular pressure in the mammalian eye

    PubMed Central

    Ryskamp, Daniel A.; Frye, Amber M.; Phuong, Tam T. T.; Yarishkin, Oleg; Jo, Andrew O.; Xu, Yong; Lakk, Monika; Iuso, Anthony; Redmon, Sarah N.; Ambati, Balamurali; Hageman, Gregory; Prestwich, Glenn D.; Torrejon, Karen Y.; Križaj, David

    2016-01-01

    An intractable challenge in glaucoma treatment has been to identify druggable targets within the conventional aqueous humor outflow pathway, which is thought to be regulated/dysregulated by elusive mechanosensitive protein(s). Here, biochemical and functional analyses localized the putative mechanosensitive cation channel TRPV4 to the plasma membrane of primary and immortalized human TM (hTM) cells, and to human and mouse TM tissue. Selective TRPV4 agonists and substrate stretch evoked TRPV4-dependent cation/Ca2+ influx, thickening of F-actin stress fibers and reinforcement of focal adhesion contacts. TRPV4 inhibition enhanced the outflow facility and lowered perfusate pressure in biomimetic TM scaffolds populated with primary hTM cells. Systemic delivery, intraocular injection or topical application of putative TRPV4 antagonist prodrug analogs lowered IOP in glaucomatous mouse eyes and protected retinal neurons from IOP-induced death. Together, these findings indicate that TRPV4 channels function as a critical component of mechanosensitive, Ca2+-signaling machinery within the TM, and that TRPV4-dependent cytoskeletal remodeling regulates TM stiffness and outflow. Thus, TRPV4 is a potential IOP sensor within the conventional outflow pathway and a novel target for treating ocular hypertension. PMID:27510430

  9. Correlation between short-term and long-term intraocular pressure fluctuation in glaucoma patients

    PubMed Central

    Tojo, Naoki; Abe, Shinya; Miyakoshi, Mari; Hayashi, Atsushi

    2016-01-01

    Purpose We investigated correlations between short-term and long-term intraocular pressure (IOP) fluctuations. Methods We examined 50 eyes of glaucoma patients who were followed for >2 years. We measured short-term IOP fluctuation using a Triggerfish® contact lens sensor (CLS). The short-term IOP fluctuation (mVeq) was defined as the difference between the maximum value and the minimum value measured during the 24-hour course with CLS. The long-term IOP fluctuation was defined by four parameters: 1) the mean IOP (mmHg) determined during follow-up; 2) the IOP difference, which was defined as the difference between the maximum IOP and the minimum IOP; 3) the standard deviation of IOP; and 4) the peak IOP, which was defined as the maximum IOP. Correlations between these parameters and the short-term IOP fluctuation were examined. Results The mean follow-up period was 5.4 years. The average IOP was 15.0±4.0 mmHg. The range of short-term IOP fluctuation identified with CLS was significantly correlated with all the four long-term IOP fluctuation parameters. Conclusion Short-term IOP fluctuations were found to be associated with long-term IOP fluctuations. Examination of 24-hour IOP fluctuations with the CLS might be useful for predicting the long-term IOP fluctuation. PMID:27621590

  10. Twenty-four–Hour Measurement of Intraocular Pressure in Guinea Pigs (Cavia porcellus)

    PubMed Central

    Ansari-Mood, Maneli; Mehdi-Rajaei, Seyed; Sadjadi, Reza; Selk-Ghaffari, Masoud; Williams, David L

    2016-01-01

    The objective of this study was to measure intraocular pressure (IOP) in intact, healthy guinea pigs (15 male, 15 female) every 2 h for a 24-h period. First, IOP was measured by using rebound tonometry (RBT). After a 1-min rest period, 0.5% proparacaine ophthalmic solution, a topical anesthetic, was applied to both eyes; 4 min after anesthetic instillation, IOP was measured by using applanation tonometry (APT). The IOP was lower during the light period (0700 to 1900) than during the dark phase (2000 to 0600). The lowest IOP by both RBT and APT (3.68 and 13.37 mm Hg, respectively) occurred at 0700, whereas maximal IOP occurred at 2300 for RBT (8.12 mm Hg) but at 2100 for APT (20.62 mm Hg). No significant differences in IOP between the left and right eyes or between RBT and APT were noted. In addition, daily variations in the IOP of guinea pigs seem to be independent of sex and body weight. The results of this study may be beneficial in the diagnosis and observation of glaucoma in guinea pigs. PMID:26817986

  11. The Application of a Contact Lens Sensor in Detecting 24-Hour Intraocular Pressure-Related Patterns

    PubMed Central

    2016-01-01

    Glaucoma is one of the leading causes of blindness worldwide. Recent studies suggest that intraocular pressure (IOP) fluctuations, peaks, and rhythm are important factors in disease advancement. Yet, current glaucoma management remains hinged on single IOP measurements during clinic hours. To overcome this limitation, 24-hour IOP monitoring devices have been employed and include self-tonometry, permanent IOP, and temporary IOP monitoring. This review discusses each IOP measuring strategy and focuses on the recently FDA-approved contact lens sensor (CLS). The CLS records IOP-related ocular patterns for 24 hours continuously. Using the CLS, IOP-related parameters have been found to be associated with the rate of visual field progression in primary open-angle glaucoma, disease progression in primary angle-closure glaucoma, and various clinical variables in ocular hypertension. The CLS has been used to quantify blink rate and limbal strain and measure the circadian rhythm in a variety of disease states including normal-tension glaucoma and thyroid eye disease. The effects of various IOP-lowering interventions were also characterized using the CLS. CLS provides a unique, safe, and well-tolerated way to study IOP-related patterns in a wide range of disease states. IOP-related patterns may help identify patients most at risk for disease progression and assist with the development of tailored treatments. PMID:27525110

  12. Effect on multifocal electroretinogram in persistently elevated intraocular pressure by erigeron breviscapus extract

    PubMed Central

    Lu, Xue-Jing; Zhang, Fu-Wen; Cheng, Lin; Liu, Ai-Qin; Duan, Jun-Guo

    2011-01-01

    AIM To observe the effect on multifocal electroretinogram (mfERG) in persistently elevated intraocular pressure (IOP) by erigeron breviscapus extract (also named Dengzhanhua in Chinese) in rat models. METHODS The rat models with persistently elevated IOP were established by the method of Akira. Then, erigeron breviscapus extract was given for one month to observe the effect on mfERG in persistently elevated IOP in rats. RESULTS As elevated IOP went on, the mfERG changes were mainly in weaken of reaction density with progressive development. After intervention of erigeron breviscapus extract, the total peak latency of P1 wave had recovered to some extent and the difference was significant when compared with control group (P<0.05); the total response density and P1 wave response density in second circle had risen noticeably, which had significant differences than those of control group (P<0.05). CONCLUSION Erigeron breviscapus extract can improve the impaired visual function of persistently elevated IOP in rats, suggesting that this extract is the effective part of erigeron breviscapus for optic neuroprotection. PMID:22553678

  13. Common genetic determinants of intraocular pressure and primary open-angle glaucoma.

    PubMed

    van Koolwijk, Leonieke M E; Ramdas, Wishal D; Ikram, M Kamran; Jansonius, Nomdo M; Pasutto, Francesca; Hysi, Pirro G; Macgregor, Stuart; Janssen, Sarah F; Hewitt, Alex W; Viswanathan, Ananth C; ten Brink, Jacoline B; Hosseini, S Mohsen; Amin, Najaf; Despriet, Dominiek D G; Willemse-Assink, Jacqueline J M; Kramer, Rogier; Rivadeneira, Fernando; Struchalin, Maksim; Aulchenko, Yurii S; Weisschuh, Nicole; Zenkel, Matthias; Mardin, Christian Y; Gramer, Eugen; Welge-Lüssen, Ulrich; Montgomery, Grant W; Carbonaro, Francis; Young, Terri L; Bellenguez, Céline; McGuffin, Peter; Foster, Paul J; Topouzis, Fotis; Mitchell, Paul; Wang, Jie Jin; Wong, Tien Y; Czudowska, Monika A; Hofman, Albert; Uitterlinden, Andre G; Wolfs, Roger C W; de Jong, Paulus T V M; Oostra, Ben A; Paterson, Andrew D; Mackey, David A; Bergen, Arthur A B; Reis, André; Hammond, Christopher J; Vingerling, Johannes R; Lemij, Hans G; Klaver, Caroline C W; van Duijn, Cornelia M

    2012-01-01

    Intraocular pressure (IOP) is a highly heritable risk factor for primary open-angle glaucoma and is the only target for current glaucoma therapy. The genetic factors which determine IOP are largely unknown. We performed a genome-wide association study for IOP in 11,972 participants from 4 independent population-based studies in The Netherlands. We replicated our findings in 7,482 participants from 4 additional cohorts from the UK, Australia, Canada, and the Wellcome Trust Case-Control Consortium 2/Blue Mountains Eye Study. IOP was significantly associated with rs11656696, located in GAS7 at 17p13.1 (p=1.4×10(-8)), and with rs7555523, located in TMCO1 at 1q24.1 (p=1.6×10(-8)). In a meta-analysis of 4 case-control studies (total N = 1,432 glaucoma cases), both variants also showed evidence for association with glaucoma (p=2.4×10(-2) for rs11656696 and p=9.1×10(-4) for rs7555523). GAS7 and TMCO1 are highly expressed in the ciliary body and trabecular meshwork as well as in the lamina cribrosa, optic nerve, and retina. Both genes functionally interact with known glaucoma disease genes. These data suggest that we have identified two clinically relevant genes involved in IOP regulation.

  14. Psychophysiological stress, elevated intraocular pressure, and acute closed-angle glaucoma.

    PubMed

    Shily, B G

    1987-11-01

    The literature suggests that stress may play a part in the precipitation of acute closed-angle glaucoma because intraocular pressure (IOP) can be affected by the emotional state of the patient. This study considers this evidence in light of what is known concerning the possible relations between psychophysiological stress and elevated IOP. Two common threads run through these observations. The first is the suggestion that stress is a significant factor in the etiology of acute closed-angle glaucoma. The second is a growing suspicion concerning the role of stress in open-angle glaucoma. There is some evidence that glaucoma induction is associated with psychophysiological stress. The role of psychosomatic factors in precipitating angle closure in eyes with an anatomically narrow angle and in raising the IOP in eyes with open angles has been noted in the literature. The implication is that stress reduction might prevent angle closure and reduce the IOP. Suggested methods for achieving these results include biofeedback, meditation, and relaxation exercises.

  15. Toward a Wirelessly Powered On-Lens Intraocular Pressure Monitoring System.

    PubMed

    Chiou, Jin-Chern; Hsu, Shun-Hsi; Liao, Yu-Te; Huang, Yu-Chieh; Yeh, Guan-Ting; Kuei, Cheng-Kai; Dai, Kai-Shiun

    2016-09-01

    This paper presents a wireless on-lens intraocular pressure monitoring system, comprising a capacitance-to-digital converter and a wirelessly powered radio-frequency identification (RFID)-compatible communication system, for sensor control and data communication. The capacitive sensor was embedded on a soft contact lens of 200 μm thickness using commercially available biocompatible lens material, to improve compliance and reduce user discomfort. The sensor chip was shown to achieve effective number of bits greater than 10 over a capacitance range up to 50 pF while consuming only 64-μW power. The on-lens capacitive sensor could detect dielectric variation caused by changes in water content from a distance of 2 cm by using incident power from an RFID reader at 20 dBm. The maximum detectable distance was 11 cm with 30-dBm incident RF power. The rise in eye tissue temperature under 30-dBm RF exposure over an interval of 1 s was simulated and found to be less than 0.01°C.

  16. Intraocular pressure (IOP) in relation to four levels of daily geomagnetic and extreme yearly solar activity

    NASA Astrophysics Data System (ADS)

    Stoupel, E.; Goldenfeld, M.; Shimshoni, M.; Siegel, R.

    1993-03-01

    The link between geomagnetic field activity (GMA), solar activity and intraocular pressure (IOP) in healthy individuals was investigated. The IOP of 485 patients (970 eyes) was recorded over three nonconsecutive years (1979, 1986, 1989) which were characterized by maximal solar activity (1979, 1989) or minimal solar activity (1986). The measurements were also correlated with four categories of GMA activity: quiet (level I0), unsettled (II0), active (III0), and stormy (IV0). Participants were also differentiated by age and sex. We found that IOP was lowest on days of level IV0 (stormy) GMA. The drop in IOP concomitant with a decrease in GMA level was more significant during periods of low solar activity and in persons over 65 years of age. There was a trend towards higher IOP values on days of levels II0 and IV0 GMA in years of high solar activity. Differences between the sexes and among individuals younger than 65 years were not significant. Our results show an interesting aspect of environmental influence on the healthy population.

  17. Intraocular pressure readings obtained through soft contact lenses using four types of tonometer

    PubMed Central

    Takenaka, Joji; Kunihara, Eriko; Rimayanti, Ulfah; Tanaka, Junko; Kaneko, Makoto; Kiuchi, Yoshiaki

    2015-01-01

    Purpose To compare the reliability and accuracy of intraocular pressure (IOP) measured while wearing soft contact lenses (SCLs) using a non-contact tonometer (NCT), Goldmann applanation tonometer (GAT), iCare rebound tonometer (RBT) and the Tono-Pen XL. Methods Twenty-six healthy subjects were examined. The IOP was measured using NCT, GAT, RBT, and the Tono-Pen XL, while the subjects wore SCLs −5.00 D, −0.50 D and +5.00 D. Bland–Altman plots and a regression analysis were used to compare the IOPs obtained with those instruments and the IOPs of the naked eyes measured using GAT (the standard IOPs in this study). Results The IOPs obtained by the Tono-Pen XL while the subjects were wearing −5.00 D, −0.50 D, and +5.00 D SCLs were significantly higher than those of the naked eyes obtained using GAT. RBT showed that the IOPs were similar to the GAT standard IOPs under all conditions. The IOPs measured with NCT and GAT while the subjects were wearing −5.00 D and −0.50 D SCLs were similar to the GAT standard IOPs. The IOPs obtained with RBT and NCT while the subjects were wearing −5.00 D and −0.50 D SCLs exhibited a good correlation with the standard IOPs. Conclusion The NCT and RBT are best when measuring IOP through hydrogel SCLs. PMID:26491250

  18. Effects of high-intensity interval vs. continuous moderate exercise on intraocular pressure.

    PubMed

    Conte, M; Baldin, A D; Russo, M R R R; Storti, L R; Caldara, A A; Cozza, H F P; Ciolac, E G

    2014-09-01

    Our purpose was to compare the acute effects of high-intensity interval training (HIT) vs. continuous moderate exercise (CME) on intraocular pressure (IOP) in healthy subjects. Fifteen young men (age=22.1±6 years) underwent 30 min of HIT (2 min of walking at 50% of reserve heart rate (HR) alternated with 1 min of running at 80% of reserve HR) and CME sessions (30 min of jogging/running at 60% of reserve HR) in random order (2-5 days between sessions). IOP was measured before (baseline), immediately after (post--exercise), 5 min after (Rec5) and 10 min after (Rec10) each exercise session. IOP was reduced post-exercise and remained reduced at Rec5 during both HIT and CME session, with no significant difference between interventions (~16% between 23%). However, IOP remained reduced at Rec10 only after HIT intervention (~19%), whereas IOP at Rec10 returned to levels similar to the observed at baseline during CME intervention. In summary, both HIT and CME equally reduced IOP immediately and 5 min after exercise session. However, only HIT was able to remain IOP reduced 10 min after exercise. These results suggest that HIT may be more effective than CME for reducing IOP in young healthy men.

  19. Intraocular pressure (IOP) in relation to four levels of daily geomagnetic and extreme yearly solar activity.

    PubMed

    Stoupel, E; Goldenfeld, M; Shimshoni, M; Siegel, R

    1993-02-01

    The link between geomagnetic field activity (GMA), solar activity and intraocular pressure (IOP) in healthy individuals was investigated. The IOP of 485 patients (970 eyes) was recorded over three nonconsecutive years (1979, 1986, 1989) which were characterized by maximal solar activity (1979, 1989) or minimal solar activity (1986). The measurements were also correlated with four categories of GMA activity: quiet (level I0), unsettled (II0), active (III0), and stormy (IV0). Participants were also differentiated by age and sex. We found that IOP was lowest on days of level IV0 (stromy) GMA. The drop in IOP concomitant with a decrease in GMA level was more significant during periods of low solar activity and in persons over 65 years of age. There was a trend towards higher IOP values on days of levels II0 and IV0 GMA in years of high solar activity. Differences between the sexes and among individuals younger than 65 years were not significant. Our results show an interesting aspect of environmental influence on the healthy population. PMID:8468099

  20. Application of Cornelian Cherry Iridoid-Polyphenolic Fraction and Loganic Acid to Reduce Intraocular Pressure

    PubMed Central

    Szumny, Dorota; Sozański, Tomasz; Kucharska, Alicja Z.; Dziewiszek, Wojciech; Piórecki, Narcyz; Magdalan, Jan; Chlebda-Sieragowska, Ewa; Kupczynski, Robert; Szeląg, Adam; Szumny, Antoni

    2015-01-01

    One of the most common diseases of old age in modern societies is glaucoma. It is strongly connected with increased intraocular pressure (IOP) and could permanently damage vision in the affected eye. As there are only a limited number of chemical compounds that can decrease IOP as well as blood flow in eye vessels, the up-to-date investigation of new molecules is important. The chemical composition of the dried Cornelian cherry (Cornus mas L.) polar, iridoid-polyphenol-rich fraction was investigated. Loganic acid (50%) and pelargonidin-3-galactoside (7%) were found as the main components. Among the other constituents, iridoid compound cornuside and the anthocyans cyanidin 3-O-galactoside, cyanidin 3-O-robinobioside, and pelargonidin 3-O-robinobioside were quantified in the fraction. In an animal model (New Zealand rabbits), the influence of loganic acid and the polyphenolic fraction isolated from Cornelian cherry fruit was investigated. We found a strong IOP-hypotensive effect for a 0.7% solution of loganic acid, which could be compared with the widely ophthalmologically used timolol. About a 25% decrease in IOP was observed within the first 3 hours of use. PMID:26124854

  1. A biodegradable ocular implant for long-term suppression of intraocular pressure.

    PubMed

    Ng, Xu Wen; Liu, Kerh Lin; Veluchamy, Amutha Barathi; Lwin, Nyein Chan; Wong, Tina T; Venkatraman, Subbu S

    2015-10-01

    Timolol maleate (TM) has been used for many years for the reduction of intraocular pressure (IOP) in glaucoma patients. However, the topical mode of administration (eyedrops) is far from optimal because of the issues of low bioavailability, high drug wastage, and lack of patient compliance. Suboptimal control of the IOP leads to disease progression and eventually to blindness. Ideally, TM is delivered to the patient so that its action is both localized and sustained for 3 months or more. In this work, we developed a subconjunctival TM microfilm for sustained, long-term delivery of TM to the eyes, using the biodegradable elastomer poly(lactide-co-caprolactone) (PLC). The copolymer is biocompatible and has flexibility and mechanical characteristics suitable for a patient-acceptable implant. Controlling the release of TM for 3 months is challenging, and this work describes how, by using a combination of multilayering and blending with poly(ethylene glycol) (PEG) copolymers, we were able to develop a TM-incorporated biodegradable film that can deliver TM at a therapeutic dose for 90 days in vitro. The data was further confirmed in a diseased primate model, with sustained IOP-lowering effects for 5 months with a single implant, with acceptable biocompatibility and partial degradation.

  2. INTRAOCULAR PRESSURE IN SOUTHERN ROCKHOPPER (EUDYPTES CHRYSOCOME) AND MACARONI PENGUINS (EUDYPTES CHRYSOLOPHUS): EVALUATION OF INFLUENCING FACTORS.

    PubMed

    Woodhouse, Sarah J; Peterson, Edward L; Schmitt, Todd; Aquino, Susette

    2016-03-01

    Ophthalmic examinations were performed on 160 macaroni penguins (Eudyptes chrysolophus) and 90 southern rockhopper penguins (Eudyptes chrysocome) at eight North American zoos and aquaria. Intraocular pressure (IOP) was measured using rebound tonometry while penguins were held in two different body positions. Correlations between IOP and factors including age, body position, eye pathology, and housing parameters were evaluated. Normal macaroni penguins had a mean IOP of 42.0 ± 9.7 mm Hg. Normal rockhopper penguins had a mean IOP of 32.9 ± 6.2 mm Hg. Neither species had significantly different IOP between sexes or between left and right eyes of the same penguin. In both species, there was a negative linear correlation between age and IOP. In the macaroni population, IOP was significantly higher when IOP measurement was performed before ophthalmic exam; this was not true in rockhoppers. In both species, IOP measured in a horizontal body position was significantly higher than IOP measured in a vertical body position. In both species, eyes with corneal lesions had significantly lower IOP than normal eyes. In the macaroni penguin, eyes with rubeosis iridis had significantly lower IOP than normal eyes. In macaroni penguins, eyes with cataracts had significantly lower mean IOP than normal eyes; this was not true for rockhoppers.

  3. Correlation between short-term and long-term intraocular pressure fluctuation in glaucoma patients

    PubMed Central

    Tojo, Naoki; Abe, Shinya; Miyakoshi, Mari; Hayashi, Atsushi

    2016-01-01

    Purpose We investigated correlations between short-term and long-term intraocular pressure (IOP) fluctuations. Methods We examined 50 eyes of glaucoma patients who were followed for >2 years. We measured short-term IOP fluctuation using a Triggerfish® contact lens sensor (CLS). The short-term IOP fluctuation (mVeq) was defined as the difference between the maximum value and the minimum value measured during the 24-hour course with CLS. The long-term IOP fluctuation was defined by four parameters: 1) the mean IOP (mmHg) determined during follow-up; 2) the IOP difference, which was defined as the difference between the maximum IOP and the minimum IOP; 3) the standard deviation of IOP; and 4) the peak IOP, which was defined as the maximum IOP. Correlations between these parameters and the short-term IOP fluctuation were examined. Results The mean follow-up period was 5.4 years. The average IOP was 15.0±4.0 mmHg. The range of short-term IOP fluctuation identified with CLS was significantly correlated with all the four long-term IOP fluctuation parameters. Conclusion Short-term IOP fluctuations were found to be associated with long-term IOP fluctuations. Examination of 24-hour IOP fluctuations with the CLS might be useful for predicting the long-term IOP fluctuation.

  4. Elevation of intraocular pressure in rodents using viral vectors targeting the trabecular meshwork.

    PubMed

    Pang, Iok-Hou; Millar, J Cameron; Clark, Abbot F

    2015-12-01

    Rodents are increasingly being used as glaucoma models to study ocular hypertension, optic neuropathy, and retinopathy. A number of different techniques are used to elevate intraocular pressure in rodent eyes by artificially obstructing the aqueous outflow pathway. Another successful technique to induce ocular hypertension is to transduce the trabecular meshwork of rodent eyes with viral vectors expressing glaucoma associated transgenes to provide more relevant models of glaucomatous damage to the trabecular meshwork. This technique has been used to validate newly discovered glaucoma pathogenesis pathways as well as to develop rodent models of primary open angle glaucoma. Ocular hypertension has successfully been induced by adenovirus 5 mediated delivery of mutant MYOC, bioactivated TGFβ2, SFRP1, DKK1, GREM1, and CD44. Advantages of this approach are: selective tropism for the trabecular meshwork, the ability to use numerous mouse strains, and the relatively rapid onset of IOP elevation. Disadvantages include mild-to-moderate ocular inflammation induced by the Ad5 vector and sometimes transient transgene expression. Current efforts are focused at discovering less immunogenic viral vectors that have tropism for the trabecular meshwork and drive sufficient transgene expression to induce ocular hypertension. This viral vector approach allows rapid proof of concept studies to study glaucomatous damage to the trabecular meshwork without the expensive and time-consuming generation of transgenic mouse lines.

  5. Intraocular Pressure, Tear Production, and Ocular Echobiometry in Guinea Pigs (Cavia porcellus).

    PubMed

    Rajaei, Seyed Mehdi; Mood, Maneli Ansari; Sadjadi, Reza; Azizi, Farzaneh

    2016-01-01

    The purpose of this study was to evaluate intraocular pressure (IOP) by means of rebound tonometry, to assess tear production by using the endodontic absorbent paper point tear test (EAPTT) and phenol red thread test (PRTT), and to determine the effects of time of day on IOP and tear production in guinea pigs. The study population comprised 24 healthy adult guinea pigs (12 male, 12 female; 48 eyes) of different breeds and ranging in age from 12 to 15 mo. IOP and tear production were measured at 3 time points (0700, 1500, and 2300) during a 24-h period. Overall values (mean ± 1 SD) were: IOP, 6.81 ± 1.41 mm Hg (range, 4.83 to 8.50); PRTT, 14.33 ± 1.35 mm (range, 12.50 to 16.83); and EAPTT, 8.54 ± 1.08 mm (range, 7.17 to 10.0 mm). In addition, ultrasound biometry was performed by using a B-mode system with linear 8-MHz transducer. This study reports reference values for IOP and tear production in guinea pigs. PMID:27423156

  6. [What to do if the intraocular pressure measurement does not appear reliable].

    PubMed

    Hamard, P

    2010-04-01

    Among the various intraocular pressure (IOP) measurement methods available today, Goldmann applanation tonometry (GAT) remains the gold standard for in-office routine IOP measurement. However, numerous factors may affect IOP measurement with GAT, namely corneal features. Before any interpretation of an IOP value, the measurement conditions should be checked and the central corneal thickness evaluated, since GAT overestimates IOP in thick corneas and underestimates IOP in thin ones. When GAT is not applicable, other IOP measurement devices, which have their own limits, are available. For example, the ocular response analyzer (ORA) and dynamic contour tonometry (DCT) provide IOP readings that are less influenced by corneal properties and may be useful after refractive surgery. Regardless of the choice of tonometer, the IOP value must not be considered alone but from a clinical point of view, including, namely, multiple IOP measurements over a day since the IOP fluctuates over a 24-h time period. A complete clinical examination is necessary in each case to search for glaucomatous neuropathy. PMID:20347507

  7. Sustained intraocular pressure reduction throughout the day with travoprost ophthalmic solution 0.004%

    PubMed Central

    Dubiner, Harvey B; Noecker, Robert

    2012-01-01

    Background The purpose of this study was to characterize intraocular pressure (IOP) reduction throughout the day with travoprost ophthalmic solution 0.004% dosed once daily in the evening. Methods The results of seven published, randomized clinical trials including at least one arm in which travoprost 0.004% was dosed once daily in the evening were integrated. Means (and standard deviations) of mean baseline and on-treatment IOP, as well as mean IOP reduction and mean percent IOP reduction at 0800, 1000, and 1600 hours at weeks 2 and 12 were calculated. Results From a mean baseline IOP ranging from 25.0 to 27.2 mmHg, mean IOP on treatment ranged from 17.4 to 18.8 mmHg across all visits and time points. Mean IOP reductions from baseline ranged from 7.6 to 8.4 mmHg across visits and time points, representing a mean IOP reduction of 30%. Results of the safety analysis were consistent with the results from the individual studies for travoprost ophthalmic solution 0.004%, with ocular hyperemia being the most common side effect. Conclusion Travoprost 0.004% dosed once daily in the evening provides sustained IOP reduction throughout the 24-hour dosing interval in subjects with ocular hypertension or open-angle glaucoma. No reduction of IOP-lowering efficacy was observed at the 1600-hour time point which approached the end of the dosing interval. PMID:22536047

  8. Safety and efficacy of travoprost solution for the treatment of elevated intraocular pressure

    PubMed Central

    Quaranta, Luciano; Riva, Ivano; Katsanos, Andreas; Floriani, Irene; Centofanti, Marco; Konstas, Anastasios G P

    2015-01-01

    Travoprost is a prostaglandin analogue widely used for reducing intraocular pressure (IOP) in patients affected with glaucoma and ocular hypertension. It exerts its ocular hypotensive effect through the prostaglandin FP receptors, located in the ciliary muscle and the trabecular meshwork. Several studies have shown that topical administration of travoprost induces a mean IOP reduction ranging from 25% to 32%, and sustained throughout the 24-hour cycle. When compared with timolol, travoprost is more effective at reducing IOP, while generally no difference has been found in the head-to-head comparison with other prostaglandin analogues. The fixed combination of travoprost and timolol has demonstrated a hypotensive efficacy comparable to the concomitant administration of the two drugs. Recently, a new preservative-free formulation of travoprost 0.004% has been marketed for reducing tolerability-related problems in subjects affected with ocular surface disease. Low rates of topical and systemic adverse reactions, strong ocular hypotensive efficacy, and once-a-day dosing make travoprost a first-line treatment for patients affected with elevated IOP. PMID:25914522

  9. Genome-wide association study and meta-analysis of intraocular pressure.

    PubMed

    Ozel, A Bilge; Moroi, Sayoko E; Reed, David M; Nika, Melisa; Schmidt, Caroline M; Akbari, Sara; Scott, Kathleen; Rozsa, Frank; Pawar, Hemant; Musch, David C; Lichter, Paul R; Gaasterland, Doug; Branham, Kari; Gilbert, Jesse; Garnai, Sarah J; Chen, Wei; Othman, Mohammad; Heckenlively, John; Swaroop, Anand; Abecasis, Gonçalo; Friedman, David S; Zack, Don; Ashley-Koch, Allison; Ulmer, Megan; Kang, Jae H; Liu, Yutao; Yaspan, Brian L; Haines, Jonathan; Allingham, R Rand; Hauser, Michael A; Pasquale, Louis; Wiggs, Janey; Richards, Julia E; Li, Jun Z

    2014-01-01

    Elevated intraocular pressure (IOP) is a major risk factor for glaucoma and is influenced by genetic and environmental factors. Recent genome-wide association studies (GWAS) reported associations with IOP at TMCO1 and GAS7, and with primary open-angle glaucoma (POAG) at CDKN2B-AS1, CAV1/CAV2, and SIX1/SIX6. To identify novel genetic variants and replicate the published findings, we performed GWAS and meta-analysis of IOP in >6,000 subjects of European ancestry collected in three datasets: the NEI Glaucoma Human genetics collaBORation, GLAUcoma Genes and ENvironment study, and a subset of the Age-related Macular Degeneration-Michigan, Mayo, AREDS and Pennsylvania study. While no signal achieved genome-wide significance in individual datasets, a meta-analysis identified significant associations with IOP at TMCO1 (rs7518099-G, p = 8.0 × 10(-8)). Focused analyses of five loci previously reported for IOP and/or POAG, i.e., TMCO1, CDKN2B-AS1, GAS7, CAV1/CAV2, and SIX1/SIX6, revealed associations with IOP that were largely consistent across our three datasets, and replicated the previously reported associations in both effect size and direction. These results confirm the involvement of common variants in multiple genomic regions in regulating IOP and/or glaucoma risk.

  10. The Application of a Contact Lens Sensor in Detecting 24-Hour Intraocular Pressure-Related Patterns.

    PubMed

    Xu, Sarah C; Gauthier, Angela C; Liu, Ji

    2016-01-01

    Glaucoma is one of the leading causes of blindness worldwide. Recent studies suggest that intraocular pressure (IOP) fluctuations, peaks, and rhythm are important factors in disease advancement. Yet, current glaucoma management remains hinged on single IOP measurements during clinic hours. To overcome this limitation, 24-hour IOP monitoring devices have been employed and include self-tonometry, permanent IOP, and temporary IOP monitoring. This review discusses each IOP measuring strategy and focuses on the recently FDA-approved contact lens sensor (CLS). The CLS records IOP-related ocular patterns for 24 hours continuously. Using the CLS, IOP-related parameters have been found to be associated with the rate of visual field progression in primary open-angle glaucoma, disease progression in primary angle-closure glaucoma, and various clinical variables in ocular hypertension. The CLS has been used to quantify blink rate and limbal strain and measure the circadian rhythm in a variety of disease states including normal-tension glaucoma and thyroid eye disease. The effects of various IOP-lowering interventions were also characterized using the CLS. CLS provides a unique, safe, and well-tolerated way to study IOP-related patterns in a wide range of disease states. IOP-related patterns may help identify patients most at risk for disease progression and assist with the development of tailored treatments. PMID:27525110

  11. INTRAOCULAR PRESSURE IN SOUTHERN ROCKHOPPER (EUDYPTES CHRYSOCOME) AND MACARONI PENGUINS (EUDYPTES CHRYSOLOPHUS): EVALUATION OF INFLUENCING FACTORS.

    PubMed

    Woodhouse, Sarah J; Peterson, Edward L; Schmitt, Todd; Aquino, Susette

    2016-03-01

    Ophthalmic examinations were performed on 160 macaroni penguins (Eudyptes chrysolophus) and 90 southern rockhopper penguins (Eudyptes chrysocome) at eight North American zoos and aquaria. Intraocular pressure (IOP) was measured using rebound tonometry while penguins were held in two different body positions. Correlations between IOP and factors including age, body position, eye pathology, and housing parameters were evaluated. Normal macaroni penguins had a mean IOP of 42.0 ± 9.7 mm Hg. Normal rockhopper penguins had a mean IOP of 32.9 ± 6.2 mm Hg. Neither species had significantly different IOP between sexes or between left and right eyes of the same penguin. In both species, there was a negative linear correlation between age and IOP. In the macaroni population, IOP was significantly higher when IOP measurement was performed before ophthalmic exam; this was not true in rockhoppers. In both species, IOP measured in a horizontal body position was significantly higher than IOP measured in a vertical body position. In both species, eyes with corneal lesions had significantly lower IOP than normal eyes. In the macaroni penguin, eyes with rubeosis iridis had significantly lower IOP than normal eyes. In macaroni penguins, eyes with cataracts had significantly lower mean IOP than normal eyes; this was not true for rockhoppers. PMID:27010282

  12. Application of Cornelian Cherry Iridoid-Polyphenolic Fraction and Loganic Acid to Reduce Intraocular Pressure.

    PubMed

    Szumny, Dorota; Sozański, Tomasz; Kucharska, Alicja Z; Dziewiszek, Wojciech; Piórecki, Narcyz; Magdalan, Jan; Chlebda-Sieragowska, Ewa; Kupczynski, Robert; Szeląg, Adam; Szumny, Antoni

    2015-01-01

    One of the most common diseases of old age in modern societies is glaucoma. It is strongly connected with increased intraocular pressure (IOP) and could permanently damage vision in the affected eye. As there are only a limited number of chemical compounds that can decrease IOP as well as blood flow in eye vessels, the up-to-date investigation of new molecules is important. The chemical composition of the dried Cornelian cherry (Cornus mas L.) polar, iridoid-polyphenol-rich fraction was investigated. Loganic acid (50%) and pelargonidin-3-galactoside (7%) were found as the main components. Among the other constituents, iridoid compound cornuside and the anthocyans cyanidin 3-O-galactoside, cyanidin 3-O-robinobioside, and pelargonidin 3-O-robinobioside were quantified in the fraction. In an animal model (New Zealand rabbits), the influence of loganic acid and the polyphenolic fraction isolated from Cornelian cherry fruit was investigated. We found a strong IOP-hypotensive effect for a 0.7% solution of loganic acid, which could be compared with the widely ophthalmologically used timolol. About a 25% decrease in IOP was observed within the first 3 hours of use. PMID:26124854

  13. Regulation of intraocular pressure by soluble and membrane guanylate cyclases and their role in glaucoma

    PubMed Central

    Buys, Emmanuel S.; Potter, Lincoln R.; Pasquale, Louis R.; Ksander, Bruce R.

    2014-01-01

    Glaucoma is a progressive optic neuropathy characterized by visual field defects that ultimately lead to irreversible blindness (Alward, 2000; Anderson et al., 2006). By the year 2020, an estimated 80 million people will have glaucoma, 11 million of which will be bilaterally blind. Primary open-angle glaucoma (POAG) is the most common type of glaucoma. Elevated intraocular pressure (IOP) is currently the only risk factor amenable to treatment. How IOP is regulated and can be modulated remains a topic of active investigation. Available therapies, mostly geared toward lowering IOP, offer incomplete protection, and POAG often goes undetected until irreparable damage has been done, highlighting the need for novel therapeutic approaches, drug targets, and biomarkers (Heijl et al., 2002; Quigley, 2011). In this review, the role of soluble (nitric oxide (NO)-activated) and membrane-bound, natriuretic peptide (NP)-activated guanylate cyclases that generate the secondary signaling molecule cyclic guanosine monophosphate (cGMP) in the regulation of IOP and in the pathophysiology of POAG will be discussed. PMID:24904270

  14. Preventive Dorzolamide-Timolol for Rising Intraocular Pressure During Steep Trendelenburg Position Surgery.

    PubMed

    Molloy, Bonnie Lee; Cong, Xiamei; Watson, Charles

    2016-06-01

    The study purpose was to evaluate preventive use of dorzolamide-timolol ophthalmic solution (Cosopt) during laparoscopic surgery with the patient in steep Trendelenburg (ST) position. Periorbital swelling, venous congestion, and elevated intraocular pressure (IOP) may produce low ocular perfusion. Prompt IOP reduction is important because 30- to 40-minute episodes of acute IOP elevations can result in retinal ganglion cell dysfunction. Dorzolamide-timolol ophthalmic drops reduce IOP and may ameliorate this effect. A double-blind randomized experimental study was conducted to test the effect of dorzolamide-timolol on IOP elevation during laparoscopic surgeries in ST position. Patients were randomly assigned to receive dorzolamide-timolol treatment or balanced salt solution following anesthesia induction. The IOP levels were measured at baseline and 30-minutes intervals throughout surgery. The generalized estimating equations model was used to analyze treatment and time effects and treatment by time interactions. Ninety patients were recruited, with 46 receiving dorzolamide-timolol treatment and 44 receiving balanced salt solution. Statistical analysis revealed significant treatment and time effects and treatment-time interactions on IOP. Patients' IOP was significantly lower in the treatment group than controls (P < .05 to P < .001). Treatment effects were medium to strong. Prophylactic therapy with dorzolamide-timolol significantly reduced IOP of surgical patients during ST positioning. PMID:27501654

  15. Toward a Wirelessly Powered On-Lens Intraocular Pressure Monitoring System.

    PubMed

    Chiou, Jin-Chern; Hsu, Shun-Hsi; Liao, Yu-Te; Huang, Yu-Chieh; Yeh, Guan-Ting; Kuei, Cheng-Kai; Dai, Kai-Shiun

    2016-09-01

    This paper presents a wireless on-lens intraocular pressure monitoring system, comprising a capacitance-to-digital converter and a wirelessly powered radio-frequency identification (RFID)-compatible communication system, for sensor control and data communication. The capacitive sensor was embedded on a soft contact lens of 200 μm thickness using commercially available biocompatible lens material, to improve compliance and reduce user discomfort. The sensor chip was shown to achieve effective number of bits greater than 10 over a capacitance range up to 50 pF while consuming only 64-μW power. The on-lens capacitive sensor could detect dielectric variation caused by changes in water content from a distance of 2 cm by using incident power from an RFID reader at 20 dBm. The maximum detectable distance was 11 cm with 30-dBm incident RF power. The rise in eye tissue temperature under 30-dBm RF exposure over an interval of 1 s was simulated and found to be less than 0.01°C. PMID:27479980

  16. Continuous 24-hour intraocular pressure monitoring for glaucoma--time for a paradigm change.

    PubMed

    Mansouri, K; Weinreb, R

    2012-01-01

    Glaucoma is the main cause of irreversible blindness and intraocular pressure (IOP) is its only modifiable risk factor. The importance of robust lowering of IOP for prevention of glaucoma onset and progression is well established. Although IOP is a dynamic parameter with individual circadian rhythms, current management usually relies on single IOP measurements during regular clinic hours performed a few times a year. Recent technological advances have provided clinicians with tools for continuous IOP monitoring during a 24 hour period in an ambulatory setting. There are two approaches being investigated. The first is permanent IOP monitoring through an implantable sensor and the other is temporary monitoring through a contact lens sensor. In this article, we discuss the shortcomings of the current gold standard for tonometry (Goldmann Applanation Tonometry) and the current experience with the first commercially available continuous 24 hour IOP monitoring technology (SENSIMED Triggerfish®); a telemetric contact lens sensor produced by a Swiss start-up company (Sensimed AG, Lausanne, Switzerland). Recent studies suggest that 24 hour continuous monitoring of IOP can be integrated into clinical practice and have the potential to contribute to the reduction of glaucoma-related vision loss.

  17. Allometry and Scaling of the Intraocular Pressure and Aqueous Humour Flow Rate in Vertebrate Eyes

    PubMed Central

    Zouache, Moussa A.; Eames, Ian; Samsudin, Amir

    2016-01-01

    In vertebrates, intraocular pressure (IOP) is required to maintain the eye into a shape allowing it to function as an optical instrument. It is sustained by the balance between the production of aqueous humour by the ciliary body and the resistance to its outflow from the eye. Dysregulation of the IOP is often pathological to vision. High IOP may lead to glaucoma, which is in man the second most prevalent cause of blindness. Here, we examine the importance of the IOP and rate of formation of aqueous humour in the development of vertebrate eyes by performing allometric and scaling analyses of the forces acting on the eye during head movement and the energy demands of the cornea, and testing the predictions of the models against a list of measurements in vertebrates collated through a systematic review. We show that the IOP has a weak dependence on body mass, and that in order to maintain the focal length of the eye, it needs to be an order of magnitude greater than the pressure drop across the eye resulting from gravity or head movement. This constitutes an evolutionary constraint that is common to all vertebrates. In animals with cornea-based optics, this constraint also represents a condition to maintain visual acuity. Estimated IOPs were found to increase with the evolution of terrestrial animals. The rate of formation of aqueous humour was found to be adjusted to the metabolic requirements of the cornea, scaling as Vac0.67, where Vac is the volume of the anterior chamber. The present work highlights an interdependence between IOP and aqueous flow rate crucial to ocular function that must be considered to understand the evolution of the dioptric apparatus. It should also be taken into consideration in the prevention and treatment of glaucoma. PMID:26990431

  18. The relation between intraocular pressure change and plasma natriuretic peptide under simulated hypobaric conditions

    PubMed Central

    Karadag, Remzi; Sen, Ahmet; Yildirim, Nilgun; Basmak, Hikmet; Golemez, Haydar; Cakir, Erdinc; Akin, Ahmet

    2010-01-01

    Purpose: To ascertain whether the changes in intraocular pressure (IOP) that occur during hypobaric hypoxic exposure are related to plasma N-terminal pro-brain natriuretic peptide (BNP) levels. Materials and Methods: The study group comprised 26 healthy participants (all male, mean age 23.1 years). IOP was measured at local ground level, (792 m above sea level), then while in a chamber providing hypobaric hypoxic conditions (the subjects were exposed to a pressure equivalent to 9144 m for 1-3 min), and again after exit from the chamber. In each condition, the mean of three consecutive measurements of IOP was calculated for each eye. For BNP measurements, blood samples were drawn before the participants entered the chamber and just after they left the chamber. Results: IOP during hypobaric hypoxic exposure (18.00 ± 3.70 mmHg) was significantly greater than that before (15.66 ± 2.10 mmHg, P < 0.001) or after (16.10 ± 2.63 mmHg, P = 0.001) the exposure. IOP levels before and after the exposure were not significantly different (P = 0.136). Plasma BNP levels measured before and after exposure to hypobaric hypoxic conditions were not significantly different (P = 0.462). Conclusion: Plasma BNP levels did not change after short-term hypobaric hypoxic exposure, while the IOP increased. This increase may have been caused by some other systemic factors. As the hypobaric hypoxic conditions were reversed, IOP decreased to normal levels. PMID:20413920

  19. Effect of cisatracurium versus atracurium on intraocular pressure in patients undergoing tracheal intubation for general anesthesia

    PubMed Central

    Jabalameli, Mitra; Soltani, Hassan Ali; Hashemi, Jalal; Rahimi, Mojtaba

    2011-01-01

    BACKGROUND: Increase in intraocular pressure (IOP) following tracheal intubation during general anesthesia can be troublesome. We compared the influence of two muscle relaxants, cisatracurium and atracurium, on IOP in patients undergoing general anesthesia. METHODS: This randomized, double-blind, comparative trial was conducted on 90 candidates for elective non-ophthalmic surgery under general anesthesia. Patients were 18 to 60 years old with the American Society of Anesthesiologists (ASA) class of I or II. Anesthesia was induced with fentanyl (1.5 mg/kg) and sodium thiopental (5 mg/kg). Patients received atracurium (0.5 mg/kg) or cisatracurium (0.15 mg/kg) two minutes prior to tracheal intubation. IOP, systolic (SBP) and diastolic blood pressure (DBP), and heart rate (HR) were measured at baseline (before medication), after medication (before intubation), and 2, 5, and 10 minutes after intubation. RESULTS: In both groups IOP decreased after administration of muscle relaxants (-3.3 ± 3.6 mmHg), then increased 2 minutes after intubation (5.5 ± 4.4 mmHg), but decreased 5 (-3.3 ± 3.3 mmHg) and 10 (-0.5 ± 2.6 mmHg) minutes after intubation. IOP and SBP were significantly higher in the atracurium compared with the cisatracurium group after 2 (p < 0.001 and 0.002, respectively), 5 (p < 0.001 and 0.012, respectively), and 10 (p = 0.02 and 0.048, respectively) minutes after intubation. CONCLUSIONS: Compared with atracurium, administration of cisatracurium can better prevent the increase of IOP following tracheal intubation in general anesthesia. The observed difference might be related to different effects on hemodynamic variables. Application of these results in patients under ophthalmic surgery is warranted. PMID:22247724

  20. Seasonal changes of 24-hour intraocular pressure rhythm in healthy Shanghai population

    PubMed Central

    Cheng, Jingyi; Xiao, Ming; Xu, Huan; Fang, Shaobin; Chen, Xu; Kong, Xiangmei; Sun, Xinghuai

    2016-01-01

    Abstract The aim of the present study was to investigate and compare the 24-hour intraocular pressure (IOP) rhythms in winter and summer in the healthy population of Shanghai, China. This is a cross-sectional study in which 24-hour IOP measurements were taken for all eligible healthy volunteers in winter and summer, respectively, and the temperature, hours of sunlight (sunlight time), and circulatory parameters, including heart rate, systolic blood pressure, and diastolic blood pressure, were also recorded. The 24-hour IOP curves and IOP parameters (mean, peak, trough, and fluctuation of IOP together with the diurnal-to-nocturnal IOP change) in winter and summer were obtained and compared. The magnitude of IOP changes from summer to winter was also calculated. A total of 29 participants (58 eyes), 14 (48.28%) male and 15 (51.72%) female, aged 43.66 ± 12.20 (19–61) years, were considered eligible for this study. Generally, IOP decreased progressively before noon, increased notably in the nocturnal period, and peaked at 12:00 am in winter and at 2:00 am in summer. The pattern of 24-hour IOP in winter and summer was significantly different (P = 0.002). The average IOPs from 4:00 pm to 8:00 am, except for 6:00 am, were significantly higher in winter (P < 0.05). However, no significant differences were shown after adjusting for temperature and/or sunlight time. From summer to winter, the extent of IOP increase was mostly around 0 to 3 mm Hg, and the IOPs increased more significantly in the nocturnal period than in the diurnal period (P = 0.05). The 24-hour IOP rhythms were different in winter and summer, with higher IOP level in winter. Temperature and sunlight time, which are independent of heart rate and blood pressure, affected the 24-hour IOP rhythms in healthy people in Shanghai, China. Further investigations are expected for the rhythm of some endogenous substance secretion and the inner mechanism of regulation of IOP. PMID:27495076

  1. The Diurnal and Nocturnal Effect of Travoprost with SofZia on Intraocular Pressure and Ocular Perfusion Pressure

    PubMed Central

    Seibold, Leonard K.; Kahook, Malik Y.

    2013-01-01

    Purpose To determine the 24-hour effects of travoprost with sofZia on intraocular pressure (IOP) and ocular perfusion pressure as well as the endurance of IOP lowering after last dosing. Design Prospective, open-label study Methods Forty subjects with open angle glaucoma or ocular hypertension were admitted to our sleep laboratory for three 24-hour sessions monitoring IOP, blood pressure (BP), and heart rate. The first baseline session occurred after medication washout or immediately after enrollment for treatment naive patients. A second 24-hour monitoring session was performed after four weeks of once nightly treatment of travoprost with sofZia. The medication was then discontinued and a third 24-hour session was completed 60-84 hours after the last dose taken. IOP measurements were taken using a pneumotonometer every two hours in the sitting position during the 16-hour diurnal period and in the supine position during the 8-hour nocturnal period. Ocular perfusion pressure was defined as 2/3[diastolic BP + 1/3(systolic BP - diastolic BP)] - IOP. Results Treatment with travoprost with sofZia significantly lowered mean diurnal and nocturnal IOP levels from baseline (Diurnal 18.1±3.9 to 15.3±3.3 mm Hg; Nocturnal 20.6±3.6 to 19.4±3.4 mm Hg, p<0.01 for both). Once treatment was discontinued, mean IOP remained at levels significantly less than baseline during both the diurnal (16.6±3.8 mm Hg) and nocturnal periods (19.4±3.5 mm Hg). Mean baseline ocular perfusion pressure was significantly increased during the diurnal but not the nocturnal period (Diurnal 73.7±11.4 to 76.5±10.3 mm Hg, p=0.01; Nocturnal 64.4±12.6 to 64.2±11.1 mm Hg, p=0.67). Conclusion Travoprost with sofZia significantly lowers IOP throughout the diurnal and nocturnal periods, and increases ocular perfusion pressure in the diurnal, but not the nocturnal period in open angle glaucoma and ocular hypertension. The treatment effect on IOP endures for at least 84 hours after the last dose. PMID

  2. Intraocular pressure dynamics with prostaglandin analogs: a clinical application of the water-drinking test

    PubMed Central

    Özyol, Pelin; Özyol, Erhan; Baldemir, Ercan

    2016-01-01

    Aim To evaluate the clinical applicability of the water-drinking test in treatment-naive primary open-angle glaucoma patients. Methods Twenty newly diagnosed primary open-angle glaucoma patients and 20 healthy controls were enrolled in this prospective study. The water-drinking test was performed at baseline and 6 weeks and 3 months after prostaglandin analog treatment. Peak and fluctuation of intraocular pressure (IOP) measurements obtained with the water-drinking test during follow-up were analyzed. Analysis of variance for repeated measures and paired and unpaired t-tests were used for statistical analysis. Results The mean baseline IOP values in patients with primary open-angle glaucoma were 25.1±4.6 mmHg before prostaglandin analog treatment, 19.8±3.7 mmHg at week 6, and 17.9±2.2 mmHg at month 3 after treatment. The difference in mean baseline IOP of the water-drinking tests was statistically significant (P<0.001). At 6 weeks of prostaglandin analog treatment, two patients had high peak and fluctuation of IOP measurements despite a reduction in baseline IOP. After modifying treatment, patients had lower peak and fluctuation of IOP values at month 3 of the study. Conclusion Peak and fluctuation of IOP in response to the water-drinking test were lower with prostaglandin analogs compared with before medication. The water-drinking test can represent an additional benefit in the management of glaucoma patients, especially by detecting higher peak and fluctuation of IOP values despite a reduced mean IOP. Therefore, it could be helpful as a supplementary method in monitoring IOP in the clinical practice. PMID:27555742

  3. Relationship between Corneal Temperature and Intraocular Pressure in Healthy Individuals: A Clinical Thermographic Analysis

    PubMed Central

    Fabiani, Claudia; Li Voti, Roberto; Rusciano, Dario; Mutolo, Maria Giulia; Pescosolido, Nicola

    2016-01-01

    Purpose. To study the geographical distribution of corneal temperature (CT) and its influence on the intraocular pressure (IOP) of healthy human volunteers. Materials and Methods. Fifteen subjects (7 M, 8 F), 33.8 ± 17.4 years old, were enrolled in this pilot, cross-sectional study. Measurements of CT were taken after one hour with closed eyelids (CET) or closed eyelids with a cooling mask (cm-CET) and compared to baseline. Results. If compared to baseline, after CET, average CT significantly increased by 0.56°C in the RE and by 0.48°C in the LE (p < 0.001) and IOP concomitantly significantly increased by 1.13 mmHg and 1.46 mmHg, respectively, in each eye (p < 0.001). After cm-CET, average CT significantly decreased by 0.11°C and 0.20°C, respectively, in the RE and LE (RE p = 0.04; LE p = 0.024), followed by a significant IOP decrease of 2.19 mmHg and 1.54 mmHg, respectively, in each eye (RE p < 0.001; LE p = 0.0019). Conclusion. Significant variations of CT occurred after CET and cm-CET and were directly correlated with significant differences of IOP. It can be speculated that both oxidative stress and sympathetic nerve fiber stimulation by temperature oscillations may affect the regulation of AH vortex flow and turnover, thus influencing IOP values. PMID:26904273

  4. Does Rebound Tonometry Probe Misalignment Modify Intraocular Pressure Measurements in Human Eyes?

    PubMed Central

    Beasley, Ian G.; Laughton, Deborah S.; Coldrick, Benjamin J.; Drew, Thomas E.; Sallah, Marium; Davies, Leon N.

    2013-01-01

    Purpose. To examine the influence of positional misalignments on intraocular pressure (IOP) measurement with a rebound tonometer. Methods. Using the iCare rebound tonometer, IOP readings were taken from the right eye of 36 healthy subjects at the central corneal apex (CC) and compared to IOP measures using the Goldmann applanation tonometer (GAT). Using a bespoke rig, iCare IOP readings were also taken 2 mm laterally from CC, both nasally and temporally, along with angular deviations of 5 and 10 degrees, both nasally and temporally to the visual axis. Results. Mean IOP ± SD, as measured by GAT, was 14.7 ± 2.5 mmHg versus iCare tonometer readings of 17.4 ± 3.6 mmHg at CC, representing an iCare IOP overestimation of 2.7 ± 2.8 mmHg (P < 0.001), which increased at higher average IOPs. IOP at CC using the iCare tonometer was not significantly different to values at lateral displacements. IOP was marginally underestimated with angular deviation of the probe but only reaching significance at 10 degrees nasally. Conclusions. As shown previously, the iCare tonometer overestimates IOP compared to GAT. However, IOP measurement in normal, healthy subjects using the iCare rebound tonometer appears insensitive to misalignments. An IOP underestimation of <1 mmHg with the probe deviated 10 degrees nasally reached statistical but not clinical significance levels. PMID:24073330

  5. Characterization of intraocular pressure responses of the Tibetan monkey (Macaca thibetana)

    PubMed Central

    Liu, Guo; Zeng, Tao; Yu, Wenhan; Yan, Naihong; Wang, Hongxing; Cai, Su-ping; Pang, Iok-Hou

    2011-01-01

    Purpose To characterize the effects of circadian rhythm, feeding time, age, general anesthesia, and ocular hypotensive compounds on intraocular pressure (IOP) of the Tibetan monkey (Macaca thibetana). Methods Tibetan monkeys were trained for IOP measurement with the TonoVet® rebound tonometer without sedation or anesthesia. Their circadian IOP fluctuation was monitored every 3 h. Effects of changing the feeding time, general anesthesia, age (2–3 year-old versus 8–15 year-old animals), and various pharmacological agents, such as travoprost, timolol, naphazoline and spiradoline, on IOP were also evaluated. Results After behavioral training, conscious Tibetan monkeys were receptive to IOP measurement. The lowest and highest IOP values in a circadian cycle were recorded at 3:00 AM (19.8±0.4 mmHg, mean±SEM, n=12) and noon (29.3±0.9 mmHg), respectively. Changing the feeding time from 11:30 AM to 12:30 PM lowered the noon IOP to 25.1±1.2 mmHg. General anesthesia lowered IOP in these monkeys, while IOP of young and mature animals were similar. Three hours after topical ocular administration, travoprost reduced IOP by 5.2±0.6 mmHg (n=6, p<0.001), and timolol reduced IOP by 2.8±0.7 mmHg (p<0.05). Naphazoline and spiradoline lowered IOP by 4.8 mmHg and 2.5 mmHg (both p<0.001), respectively, 2 h after drug administration. Conclusions The circadian IOP fluctuation in conscious Tibetan monkeys and their responses to travoprost, timolol, and other experimental conditions are similar to other primates. These monkeys appear to be a suitable model for glaucoma research. PMID:21654897

  6. Extracellular matrix in the trabecular meshwork: intraocular pressure regulation and dysregulation in glaucoma.

    PubMed

    Vranka, Janice A; Kelley, Mary J; Acott, Ted S; Keller, Kate E

    2015-04-01

    The trabecular meshwork (TM) is located in the anterior segment of the eye and is responsible for regulating the outflow of aqueous humor. Increased resistance to aqueous outflow causes intraocular pressure to increase, which is the primary risk factor for glaucoma. TM cells reside on a series of fenestrated beams and sheets through which the aqueous humor flows to exit the anterior chamber via Schlemm's canal. The outer trabecular cells are phagocytic and are thought to function as a pre-filter. However, most of the outflow resistance is thought to be from the extracellular matrix (ECM) of the juxtacanalicular region, the deepest portion of the TM, and from the inner wall basement membrane of Schlemm's canal. It is becoming increasingly evident that the extracellular milieu is important in maintaining the integrity of the TM. In glaucoma, not only have ultrastructural changes been observed in the ECM of the TM, and a significant number of mutations in ECM genes been noted, but the stiffness of glaucomatous TM appears to be greater than that of normal tissue. Additionally, TGFβ2 has been found to be elevated in the aqueous humor of glaucoma patients and is assumed to be involved in ECM changes deep with the juxtacanalicular region of the TM. This review summarizes the current literature on trabecular ECM as well as the development and function of the TM. Animal models and organ culture models targeting specific ECM molecules to investigate the mechanisms of glaucoma are described. Finally, the growing number of mutations that have been identified in ECM genes and genes that modulate ECM in humans with glaucoma are documented.

  7. ARHGEF12 influences the risk of glaucoma by increasing intraocular pressure.

    PubMed

    Springelkamp, Henriët; Iglesias, Adriana I; Cuellar-Partida, Gabriel; Amin, Najaf; Burdon, Kathryn P; van Leeuwen, Elisabeth M; Gharahkhani, Puya; Mishra, Aniket; van der Lee, Sven J; Hewitt, Alex W; Rivadeneira, Fernando; Viswanathan, Ananth C; Wolfs, Roger C W; Martin, Nicholas G; Ramdas, Wishal D; van Koolwijk, Leonieke M; Pennell, Craig E; Vingerling, Johannes R; Mountain, Jenny E; Uitterlinden, André G; Hofman, Albert; Mitchell, Paul; Lemij, Hans G; Wang, Jie Jin; Klaver, Caroline C W; Mackey, David A; Craig, Jamie E; van Duijn, Cornelia M; MacGregor, Stuart

    2015-05-01

    Primary open-angle glaucoma (POAG) is a blinding disease. Two important risk factors for this disease are a positive family history and elevated intraocular pressure (IOP), which is also highly heritable. Genes found to date associated with IOP and POAG are ABCA1, CAV1/CAV2, GAS7 and TMCO1. However, these genes explain only a small part of the heritability of IOP and POAG. We performed a genome-wide association study of IOP in the population-based Rotterdam Study I and Rotterdam Study II using single nucleotide polymorphisms (SNPs) imputed to 1000 Genomes. In this discovery cohort (n = 8105), we identified a new locus associated with IOP. The most significantly associated SNP was rs58073046 (β = 0.44, P-value = 1.87 × 10(-8), minor allele frequency = 0.12), within the gene ARHGEF12. Independent replication in five population-based studies (n = 7471) resulted in an effect size in the same direction that was significantly associated (β = 0.16, P-value = 0.04). The SNP was also significantly associated with POAG in two independent case-control studies [n = 1225 cases and n = 4117 controls; odds ratio (OR) = 1.53, P-value = 1.99 × 10(-8)], especially with high-tension glaucoma (OR = 1.66, P-value = 2.81 × 10(-9); for normal-tension glaucoma OR = 1.29, P-value = 4.23 × 10(-2)). ARHGEF12 plays an important role in the RhoA/RhoA kinase pathway, which has been implicated in IOP regulation. Furthermore, it binds to ABCA1 and links the ABCA1, CAV1/CAV2 and GAS7 pathway to Mendelian POAG genes (MYOC, OPTN, WDR36). In conclusion, this study identified a novel association between IOP and ARHGEF12.

  8. Estimation of 24-Hour Intraocular Pressure Peak Timing and Variation Using a Contact Lens Sensor

    PubMed Central

    Liu, John H. K.; Mansouri, Kaweh; Weinreb, Robert N.

    2015-01-01

    Purpose To compare estimates of 24-hour intraocular pressure (IOP) peak timing and variation obtained using a contact lens sensor (CLS) and using a pneumatonometer. Methods Laboratory data collected from 30 healthy volunteers (ages, 20-66 years) in a randomized, controlled clinical trial were analyzed. Participants were housed for 24 hours in a sleep laboratory. One randomly selected right or left eye was fitted with a CLS that monitored circumferential curvature in the corneoscleral region related to the change of IOP. Electronic output signals of 30 seconds were averaged and recorded every 5 minutes. In the contralateral eye, habitual IOP measurements were taken using a pneumatonometer once every two hours. Simulated 24-hour rhythms in both eyes were determined by cosinor fitting. Simulated peak timings (acrophases) and simulated data variations (amplitudes) were compared between the paired eyes. Results Bilateral change patterns of average 24-hour data for the group were in parallel. The simulated peak timing in the CLS fitted eye occurred at 4:44 AM ± 210 min (mean ± SD) and the IOP peak timing in the contralateral eye at 4:11 AM ± 120 min (P=0.256, Wilcoxon signed-rank test). There was no significant correlation between the simulated data variations in the paired eyes (P=0.820, linear regression). Conclusions The 24-hour CLS data showed a simulated peak timing close to the 24-hour IOP peak timing obtained using the pneumatonometer. However, the simulated variations of 24-hour data in the paired eyes were not correlated. Estimated 24-hour IOP rhythms using the two devices should not be considered interchangeable. PMID:26076472

  9. Intraocular pressure measurement over soft contact lens by rebound tonometer: a comparative study

    PubMed Central

    Nacaroglu, Senay Asik; Un, Emine Seker; Ersoz, Mehmet Giray; Tasci, Yelda

    2015-01-01

    AIM To evaluate the intraocular pressure (IOP) measurements by Icare rebound tonometer over a contact lens in comparison with Goldmann applanation tonometry (GAT). METHODS Fifty patients using contact lens were included in this study. One of the eyes of the patients was selected randomly and their IOP were measured by rebound tonometer with and without contact lens (RTCL, RT respectively) and by GAT, as well as their central corneal thickness (CCT) by optical pachymeter. The results of both methods were compared by correlation analysis, general linear method repeated measure and Bland-Altman analysis. RESULTS Mean IOP values measured by RTCL, RT and GAT were 15.68±3.7, 14.50±3.4 and 14.16±2.8 (P<0.001), respectively. Mean IOP by RTCL was significantly higher than the measurements implemented by RT and GAT (P<0.001), while there was no difference between the measurements by GAT and RT (P=0.629). There was a good level of positive correlation between GAT and RTCL as well as RT (r=0.786 P<0.001, r=0.833 P<0.001, respectively). We have observed that CCT increase did not show any correlation with the differences of the measurements between RTCL and RT (P=0.329), RTCL and GAT (P=0.07) as well as RT and GAT (P=0.189) in linear regression model. CONCLUSION The average of the measurements over contact lens by rebound tonometer was found to be higher than what was measured by GAT. Although this difference is statistically significant, it may be clinically negligible in the normal population. PMID:26086004

  10. Mechanism related to reduction of intraocular pressure by melanocortins in rabbits

    PubMed Central

    Naveh, N; Kaplan-Messas, A; Marshall, J

    2000-01-01

    AIM—To investigate whether the ocular hypotensive effect of alpha melanocyte stimulating hormone (MSH) is related to eicosanoids or cyclic AMP (cAMP).
METHODS—Intraocular pressure (IOP) readings were taken at a similar time on the day before and after a single dose of topical MSH. Changes in the levels of prostaglandin E2 (PGE2) and prostacyclin in incubated iris ciliary body (ICB) explants were measured by specific radioimmunoassay (RIA). Incubated ICB explants were exposed to MSH or adrenaline (epinephrine) for a week. In addition, cAMP levels in the medium were determined following short term incubation using RIA.
RESULTS—A significant dose related reduction in IOP was noted with topical MSH (mean (SD) maximal effect 4.5 (0.1) mm Hg (21%); p<0.001 v appropriate baseline) which persisted up to 6 hours (p=0.05). MSH treated ICB explants showed a 1.5-fold increase in PGE2 and prostacyclin levels (p<0.001 for each parameter) while cAMP levels were increased twofold (p<0.001).
CONCLUSIONS—A single application of MSH caused a sustained dose related ocular hypotensive effect with no side effects. An increase in eicosanoid and cAMP levels following ICB exposure to MSH indicated their involvement in MSH induced ocular hypotension. MSH and its analogues might have clinical relevance as antiglaucoma drugs with fewer side effects because of their antiallergic and anti-inflammatory properties.

 PMID:11090484

  11. Not only pregnancy but also the number of fetuses in the uterus affects intraocular pressure

    PubMed Central

    Saylık, Metin; Saylık, Safiye A

    2014-01-01

    Aim: To investigate whether, intraocular pressure (IOP) is affected when there is a second fetus in the uterus during pregnancy. Materials and Methods: Eighty eyes of 40 twin pregnancies (TwPs), 80 eyes of 40 singleton pregnancies (SiPs) and 80 eyes of 40 non-pregnant females (NoPs) were included in the study. Statistical Analysis: Repeated measurements analysis of variance with two factors, one-way analysis of variance (ANOVA) and theTukey's multiple comparison test were used. Results: The mean IOP (MIOP) values in TwPs were 14.29 ± 1.28, 11.48 ± 1.20, and 9.81 ± 1.36 mmHg and the MIOP values in SiPs were 14.42 ± 0.95, 13.12 ± 0.75, and 10.97 ± 0.89 mmHg in subsequent trimesters. The MIOP values in NoPs were 14.77 ± 1.18, 14.92 ± 1.33, and 15.08 ± 0.89 mmHg in subsequent 3-month measurements. The results show that the MIOP values for the TwPs group were significantly lower than the SiPs in all trimesters. Conclusions: During pregnancy, the number of fetuses in the uterus is an indirectly important factor that influences the decrease in IOP. We hypothesize that the increased ocular hypotensive effect of TwPs is most likely related to the presence of higher levels of hormones, particularly estrogen, progesterone and relaxin compared with SiPs. PMID:24178401

  12. Haploinsufficient Bmp4 ocular phenotypes include anterior segment dysgenesis with elevated intraocular pressure

    PubMed Central

    Chang, Bo; Smith, Richard S; Peters, Maureen; Savinova, Olga V; Hawes, Norman L; Zabaleta, Adriana; Nusinowitz, Steven; Martin, Janice E; Davisson, Muriel L; Cepko, Constance L; Hogan, Brigid LM; John, Simon WM

    2001-01-01

    Background Glaucoma is a blinding disease usually associated with high intraocular pressure (IOP). In some families, abnormal anterior segment development contributes to glaucoma. The genes causing anterior segment dysgenesis and glaucoma in most of these families are not identified and the affected developmental processes are poorly understood. Bone morphogenetic proteins (BMPs) participate in various developmental processes. We tested the importance of Bmp4 gene dosage for ocular development and developmental glaucoma. Results Bmp4+/- mice have anterior segment abnormalities including malformed, absent or blocked trabecular meshwork and Schlemm's canal drainage structures. Mice with severe drainage structure abnormalities, over 80% or more of their angle's extent, have elevated IOP. The penetrance and severity of abnormalities is strongly influenced by genetic background, being most severe on the C57BL/6J background and absent on some other backgrounds. On the C57BL/6J background there is also persistence of the hyaloid vasculature, diminished numbers of inner retinal cells, and absence of the optic nerve. Conclusions We demonstrate that heterozygous deficiency of BMP4 results in anterior segment dysgenesis and elevated IOP. The abnormalities are similar to those in human patients with developmental glaucoma. Thus, BMP4 is a strong candidate to contribute to Axenfeld-Rieger anomaly and other developmental conditions associated with human glaucoma. BMP4 also participates in posterior segment development and wild-type levels are usually critical for optic nerve development on the C57BL/6J background. Bmp4+/- mice are useful for studying various components of ocular development, and may allow identification of strain specific modifiers affecting a variety of ocular phenotypes. PMID:11722794

  13. ARHGEF12 influences the risk of glaucoma by increasing intraocular pressure.

    PubMed

    Springelkamp, Henriët; Iglesias, Adriana I; Cuellar-Partida, Gabriel; Amin, Najaf; Burdon, Kathryn P; van Leeuwen, Elisabeth M; Gharahkhani, Puya; Mishra, Aniket; van der Lee, Sven J; Hewitt, Alex W; Rivadeneira, Fernando; Viswanathan, Ananth C; Wolfs, Roger C W; Martin, Nicholas G; Ramdas, Wishal D; van Koolwijk, Leonieke M; Pennell, Craig E; Vingerling, Johannes R; Mountain, Jenny E; Uitterlinden, André G; Hofman, Albert; Mitchell, Paul; Lemij, Hans G; Wang, Jie Jin; Klaver, Caroline C W; Mackey, David A; Craig, Jamie E; van Duijn, Cornelia M; MacGregor, Stuart

    2015-05-01

    Primary open-angle glaucoma (POAG) is a blinding disease. Two important risk factors for this disease are a positive family history and elevated intraocular pressure (IOP), which is also highly heritable. Genes found to date associated with IOP and POAG are ABCA1, CAV1/CAV2, GAS7 and TMCO1. However, these genes explain only a small part of the heritability of IOP and POAG. We performed a genome-wide association study of IOP in the population-based Rotterdam Study I and Rotterdam Study II using single nucleotide polymorphisms (SNPs) imputed to 1000 Genomes. In this discovery cohort (n = 8105), we identified a new locus associated with IOP. The most significantly associated SNP was rs58073046 (β = 0.44, P-value = 1.87 × 10(-8), minor allele frequency = 0.12), within the gene ARHGEF12. Independent replication in five population-based studies (n = 7471) resulted in an effect size in the same direction that was significantly associated (β = 0.16, P-value = 0.04). The SNP was also significantly associated with POAG in two independent case-control studies [n = 1225 cases and n = 4117 controls; odds ratio (OR) = 1.53, P-value = 1.99 × 10(-8)], especially with high-tension glaucoma (OR = 1.66, P-value = 2.81 × 10(-9); for normal-tension glaucoma OR = 1.29, P-value = 4.23 × 10(-2)). ARHGEF12 plays an important role in the RhoA/RhoA kinase pathway, which has been implicated in IOP regulation. Furthermore, it binds to ABCA1 and links the ABCA1, CAV1/CAV2 and GAS7 pathway to Mendelian POAG genes (MYOC, OPTN, WDR36). In conclusion, this study identified a novel association between IOP and ARHGEF12. PMID:25637523

  14. The effect of dorzolamide 2% on circadian intraocular pressure in cats with primary congenital glaucoma

    PubMed Central

    Sigle, Kelly J; Camaño-Garcia, Gabriel; Carriquiry, Alicia L; Betts, Daniel M; Kuehn, Markus H; McLellan, Gillian J

    2012-01-01

    Objective To determine the extent of fluctuation in circadian intraocular pressure (IOP) and the efficacy of topical dorzolamide 2% q 8h in lowering IOP and blunting circadian fluctuation in IOP in glaucomatous cats. Animals Studied 7 adult cats with primary congenital glaucoma (PCG). Procedures Measurements of IOP and pupil diameter were obtained for both eyes (OU) of each cat q 4h for 12 days. Cats were housed in a laboratory animal facility with a 12 hour light:dark cycle. Baseline values were established for 2 days. For the next 5 days, placebo (1.4% polyvinyl alcohol) was administered OU q 8h. Dorzolamide 2% (Trusopt, Merck and Co., Inc., West Point, PA) was then administered OU q 8h for a further 5 days. A multivariate mixed linear model was fitted to the data, with parameters estimated from a Bayesian perspective. The 4am time point was selected as the reference for the purposes of comparisons. Results Estimated mean IOP for the reference time point pre-treatment was symmetric (about 33mmHg OU). In all cats, IOP was significantly lower during the diurnal phase, relative to the 4 am measurements, with highest IOP observed 2-6h after the onset of the dark-phase. Circadian fluctuations in IOP were dampened during the treatment period. There was a significant decrease in IOP in all cats during the dorzolamide treatment period (estimated mean for the treatment period reference =17.9 mmHg OU). Conclusion Topical dorzolamide 2% q 8 h is effective in reducing IOP and IOP fluctuation in cats with PCG. PMID:21923823

  15. Central corneal thickness and intraocular pressure in the Cameroonian nonglaucomatous population

    PubMed Central

    Eballe, André Omgbwa; Koki, Godefroy; Ellong, Augustin; Owono, Didier; Epée, Emilienne; Bella, Lucienne Assumpta; Mvogo, Côme Ebana; Kouam, Jeanne Mayouego

    2010-01-01

    Aim: We performed a prospective, analytical study from 01 January to 31 March 2009 in the Ophthalmology Unit of the Gyneco-Obstetric and Pediatric Hospital of Yaounde, aiming to determine the profile of central corneal thickness (CCT) in the Cameroonian nonglaucomatous black population and its relationship with intraocular pressure (IOP). Results and discussion: Four hundred and eighty-five patients (970 eyes) meeting our inclusion criteria were selected for this study. The average CCT was 529.29 ± 35.9 μm in the right eye (95% confidence interval [CI]: 526.09–532.49), 528.19 ± 35.9 μm in the left eye (95% CI: 524.99–531.40) and 528.74 ± 35.89 μm in both eyes (95% CI: 526.48–531.00), range 440 to 670 μm. The average IOP was 13.01 ± 2.97 mmHg in both eyes (95% CI: 12.82–13.19). A rise in CCT by 100 μm was followed by an increase in IOP of about 2.8 mmHg (95% CI: 2.3–3.6) for both eyes taken together. Linear regression analysis showed that corneal thickness was negatively correlated with age and IOP was positively related with age. Conclusion: CCT in the Cameroonian nonglaucomatous black population was found to be lower compared with CCT values in Caucasian and Asian populations. On the basis of reference values ranging between 527 and 560 μm, an adjustment of IOP values by a correction factor is required for many Cameroonian patients. This will improve the diagnosis and follow-up of glaucoma by helping to detect true ocular hypertension. PMID:20689788

  16. Effect of topical 1% atropine sulfate on intraocular pressure in normal horses.

    PubMed

    Herring, I.P.; Pickett, J.P.; Champagne, E.S.; Troy, G.C.; Marini, M.

    2000-01-01

    OBJECTIVE: To determine the effect of topical 1% ophthalmic atropine sulfate on intraocular pressure (IOP) in ocular normotensive horses. Animals Studied Eleven clinically healthy horses. Procedures IOP was measured bilaterally twice daily, at 8 AM and 4 PM, for 5 days. No medication was applied for the first 2 days of the study. Thereafter, one eye of each horse was treated with 0.1 mL of topical 1% atropine sulfate ointment twice daily (7 AM and 7 PM) for 3 days. The contralateral eye served as a control. In eight of the horses, an additional IOP reading was taken 3 days following cessation of the atropine treatment. RESULTS: There was no significant difference in the IOP of control vs. treatment eyes in the pretreatment period, days 1 and 2 (P = 0.97 and 0.55, respectively). During the treatment period, treated eyes of 10 of the horses had significantly lower IOP than control eyes (P = 0.03). The mean IOP reduction in treated eyes, relative to untreated eyes, was 11.2%. One horse had a significant rise in IOP in the treated eye compared to the remaining study animals. The IOP of control eyes did not vary significantly over the observation period (P = 0.27). There was no significant variation in IOP between the 8 AM and 4 PM measurement (P = 0.9). CONCLUSIONS: Topical 1% atropine sulfate causes a small, but significant decline in IOP in most ocular normotensive horses. Because topical atropine may elevate IOP in some horses, it should be used with caution in the treatment of glaucoma in this species.

  17. Real-time temperature determination during retinal photocoagulation on patients

    NASA Astrophysics Data System (ADS)

    Brinkmann, Ralf; Koinzer, Stefan; Schlott, Kerstin; Ptaszynski, Lars; Bever, Marco; Baade, Alexander; Luft, Susanne; Miura, Yoko; Roider, Johann; Birngruber, Reginald

    2012-06-01

    The induced thermal damage in retinal photocoagulation depends on the temperature increase and the time of irradiation. The temperature rise is unknown due to intraocular variations in light transmission, scattering and grade of absorption in the retinal pigment epithelium (RPE) and the choroid. Thus, in clinical practice, often stronger and deeper coagulations are applied than therapeutically needed, which can lead to extended neuroretinal damage and strong pain perception. This work focuses on an optoacoustic (OA) method to determine the temperature rise in real-time during photocoagulation by repetitively exciting thermoelastic pressure transients with nanosecond probe laser pulses, which are simultaneously applied to the treatment radiation. The temperature-dependent pressure amplitudes are non-invasively detected at the cornea with an ultrasonic transducer embedded in the contact lens. During clinical treatment, temperature courses as predicted by heat diffusion theory are observed in most cases. For laser spot diameters of 100 and 300 μm, and irradiation times of 100 and 200 ms, respectively, peak temperatures range between 70°C and 85°C for mild coagulations. The obtained data look very promising for the realization of a feedback-controlled treatment, which automatically generates preselected and reproducible coagulation strengths, unburdens the ophthalmologist from manual laser dosage, and minimizes adverse effects and pain for the patient.

  18. The Effect of a Diving Mask on Intraocular Pressure in a Healthy Population

    PubMed Central

    Goenadi, Catherina Josephine; Law, David Zhiwei; Lee, Jia Wen; Ong, Ee Lin; Chee, Wai Kitt; Cheng, Jason

    2016-01-01

    Purpose Swimming goggles increase the intraocular pressure (IOP) via the periorbital frame pressure and suction effect. In comparison, diving masks have a larger frame rim and incorporate the nose. The exact effect(s) of diving masks on IOP is unknown. This study evaluates the influence of diving masks on IOP in normal, healthy subjects. Methods Tonometry was performed in both eyes of all subjects with an AVIA®Tono-Pen by a single investigator. Measurements were taken at baseline without the diving mask and with the subjects wearing a small-volume, double-window diving mask, but with the mask lenses removed. Two IOP readings in each eye were measured, and an additional reading was measured if the difference between the initial 2 was ≥2 mm Hg. Central corneal thickness (CCT) was also measured in each eye, using a contact pachymeter (OcuScan®Alcon). Results Forty eyes of 20 healthy volunteers (age 29.7 ± 9.3 years; range 21–52) were included. The mean CCT was 544.4 ± 43.5 µm. The mean IOP before the diving mask was worn had been 17.23 ± 2.18 mm Hg (n = 40). The IOP decreased by 0.43 mm Hg (p $1003c; 0.05) to 16.80 ± 2.57 mm Hg after the diving mask had been put on. There was no correlation between IOP change and age (r = 0.143, p = 0.337), gender (r = −0.174, p = 0.283) or CCT (r = −0.123, p = 0.445). Conclusion There was no increase in IOP after the diving mask had been worn. A small but statistically significant decrease in IOP was observed. This study demonstrates that unlike swimming goggles, the strap tension and frame pressure on the periorbital tissue from a diving mask does not increase IOP. Diving masks may be a suitable alternative to swimming goggles for patients with advanced glaucoma or glaucoma filtration surgery. PMID:27462262

  19. System for Rapid, Precise Modulation of Intraocular Pressure, toward Minimally-Invasive In Vivo Measurement of Intracranial Pressure.

    PubMed

    Stockslager, Max A; Samuels, Brian C; Allingham, R Rand; Klesmith, Zoe A; Schwaner, Stephen A; Forest, Craig R; Ethier, C Ross

    2016-01-01

    Pathologic changes in intracranial pressure (ICP) are commonly observed in a variety of medical conditions, including traumatic brain injury, stroke, brain tumors, and glaucoma. However, current ICP measurement techniques are invasive, requiring a lumbar puncture or surgical insertion of a cannula into the cerebrospinal fluid (CSF)-filled ventricles of the brain. A potential alternative approach to ICP measurement leverages the unique anatomy of the central retinal vein, which is exposed to both intraocular pressure (IOP) and ICP as it travels inside the eye and through the optic nerve; manipulating IOP while observing changes in the natural pulsations of the central retinal vein could potentially provide an accurate, indirect measure of ICP. As a step toward implementing this technique, we describe the design, fabrication, and characterization of a system that is capable of manipulating IOP in vivo with <0.1 mmHg resolution and settling times less than 2 seconds. In vitro tests were carried out to characterize system performance. Then, as a proof of concept, we used the system to manipulate IOP in tree shrews (Tupaia belangeri) while video of the retinal vessels was recorded and the caliber of a selected vein was quantified. Modulating IOP using our system elicited a rapid change in the appearance of the retinal vein of interest: IOP was lowered from 10 to 3 mmHg, and retinal vein caliber sharply increased as IOP decreased from 7 to 5 mmHg. Another important feature of this technology is its capability to measure ocular compliance and outflow facility in vivo, as demonstrated in tree shrews. Collectively, these proof-of-concept demonstrations support the utility of this system to manipulate IOP for a variety of useful applications in ocular biomechanics, and provide a framework for further study of the mechanisms of retinal venous pulsation. PMID:26771837

  20. System for Rapid, Precise Modulation of Intraocular Pressure, toward Minimally-Invasive In Vivo Measurement of Intracranial Pressure.

    PubMed

    Stockslager, Max A; Samuels, Brian C; Allingham, R Rand; Klesmith, Zoe A; Schwaner, Stephen A; Forest, Craig R; Ethier, C Ross

    2016-01-01

    Pathologic changes in intracranial pressure (ICP) are commonly observed in a variety of medical conditions, including traumatic brain injury, stroke, brain tumors, and glaucoma. However, current ICP measurement techniques are invasive, requiring a lumbar puncture or surgical insertion of a cannula into the cerebrospinal fluid (CSF)-filled ventricles of the brain. A potential alternative approach to ICP measurement leverages the unique anatomy of the central retinal vein, which is exposed to both intraocular pressure (IOP) and ICP as it travels inside the eye and through the optic nerve; manipulating IOP while observing changes in the natural pulsations of the central retinal vein could potentially provide an accurate, indirect measure of ICP. As a step toward implementing this technique, we describe the design, fabrication, and characterization of a system that is capable of manipulating IOP in vivo with <0.1 mmHg resolution and settling times less than 2 seconds. In vitro tests were carried out to characterize system performance. Then, as a proof of concept, we used the system to manipulate IOP in tree shrews (Tupaia belangeri) while video of the retinal vessels was recorded and the caliber of a selected vein was quantified. Modulating IOP using our system elicited a rapid change in the appearance of the retinal vein of interest: IOP was lowered from 10 to 3 mmHg, and retinal vein caliber sharply increased as IOP decreased from 7 to 5 mmHg. Another important feature of this technology is its capability to measure ocular compliance and outflow facility in vivo, as demonstrated in tree shrews. Collectively, these proof-of-concept demonstrations support the utility of this system to manipulate IOP for a variety of useful applications in ocular biomechanics, and provide a framework for further study of the mechanisms of retinal venous pulsation.

  1. Intraocular Pressure, Blood Pressure, and Retinal Blood Flow Autoregulation: A Mathematical Model to Clarify Their Relationship and Clinical Relevance

    PubMed Central

    Guidoboni, Giovanna; Harris, Alon; Cassani, Simone; Arciero, Julia; Siesky, Brent; Amireskandari, Annahita; Tobe, Leslie; Egan, Patrick; Januleviciene, Ingrida; Park, Joshua

    2014-01-01

    Purpose. This study investigates the relationship between intraocular pressure (IOP) and retinal hemodynamics and predicts how arterial blood pressure (BP) and blood flow autoregulation (AR) influence this relationship. Methods. A mathematical model is developed to simulate blood flow in the central retinal vessels and retinal microvasculature as current flowing through a network of resistances and capacitances. Variable resistances describe active and passive diameter changes due to AR and IOP. The model is validated by using clinically measured values of retinal blood flow and velocity. The model simulations for six theoretical patients with high, normal, and low BP (HBP-, NBP-, LBP-) and functional or absent AR (-wAR, -woAR) are compared with clinical data. Results. The model predicts that NBPwAR and HBPwAR patients can regulate retinal blood flow (RBF) as IOP varies between 15 and 23 mm Hg and between 23 and 29 mm Hg, respectively, whereas LBPwAR patients do not adequately regulate blood flow if IOP is 15 mm Hg or higher. Hemodynamic alterations would be noticeable only if IOP changes occur outside of the regulating range, which, most importantly, depend on BP. The model predictions are consistent with clinical data for IOP reduction via surgery and medications and for cases of induced IOP elevation. Conclusions. The theoretical model results suggest that the ability of IOP to induce noticeable changes in retinal hemodynamics depends on the levels of BP and AR of the individual. These predictions might help to explain the inconsistencies found in the clinical literature concerning the relationship between IOP and retinal hemodynamics. PMID:24876284

  2. System for Rapid, Precise Modulation of Intraocular Pressure, toward Minimally-Invasive In Vivo Measurement of Intracranial Pressure

    PubMed Central

    Stockslager, Max A.; Samuels, Brian C.; Allingham, R. Rand; Klesmith, Zoe A.; Schwaner, Stephen A.; Forest, Craig R.; Ethier, C. Ross

    2016-01-01

    Pathologic changes in intracranial pressure (ICP) are commonly observed in a variety of medical conditions, including traumatic brain injury, stroke, brain tumors, and glaucoma. However, current ICP measurement techniques are invasive, requiring a lumbar puncture or surgical insertion of a cannula into the cerebrospinal fluid (CSF)-filled ventricles of the brain. A potential alternative approach to ICP measurement leverages the unique anatomy of the central retinal vein, which is exposed to both intraocular pressure (IOP) and ICP as it travels inside the eye and through the optic nerve; manipulating IOP while observing changes in the natural pulsations of the central retinal vein could potentially provide an accurate, indirect measure of ICP. As a step toward implementing this technique, we describe the design, fabrication, and characterization of a system that is capable of manipulating IOP in vivo with <0.1 mmHg resolution and settling times less than 2 seconds. In vitro tests were carried out to characterize system performance. Then, as a proof of concept, we used the system to manipulate IOP in tree shrews (Tupaia belangeri) while video of the retinal vessels was recorded and the caliber of a selected vein was quantified. Modulating IOP using our system elicited a rapid change in the appearance of the retinal vein of interest: IOP was lowered from 10 to 3 mmHg, and retinal vein caliber sharply increased as IOP decreased from 7 to 5 mmHg. Another important feature of this technology is its capability to measure ocular compliance and outflow facility in vivo, as demonstrated in tree shrews. Collectively, these proof-of-concept demonstrations support the utility of this system to manipulate IOP for a variety of useful applications in ocular biomechanics, and provide a framework for further study of the mechanisms of retinal venous pulsation. PMID:26771837

  3. Intraocular Pressure Rise in Subjects with and without Glaucoma during Four Common Yoga Positions

    PubMed Central

    Jasien, Jessica V.; Jonas, Jost B.; de Moraes, C. Gustavo; Ritch, Robert

    2015-01-01

    Purpose To measure changes in intraocular pressure (IOP) in association with yoga exercises with a head-down position. Methods The single Center, prospective, observational study included 10 subjects with primary open-angle glaucoma and 10 normal individuals, who performed the yoga exercises of Adho Mukha Svanasana, Uttanasana, Halasana and Viparita Karani for two minutes each. IOP was measured by pneumatonometry at baseline and during and after the exercises. Results All yoga poses were associated with a significant (P<0.01) rise in IOP within one minute after assuming the yoga position. The highest IOP increase (P<0.01) was measured in the Adho Mukha Svanasana position (IOP increase from 17±3.2 mmHg to 28±3.8 mmHg in glaucoma patients; from 17±2.8 mmHg to 29±3.9 mmHg in normal individuals), followed by the Uttanasana position (17±3.9 mmHg to 27±3.4 mmHg (glaucoma patients) and from 18±2.5 mmHg to 26±3.6 mmHg normal individuals)), the Halasana position (18±2.8 mmHg to 24±3.5 mmHg (glaucoma patients); 18±2.7 mmHg to 22±3.4 mmHg (normal individuals)), and finally the Viparita Kirani position (17±4 mmHg to 21±3.6 mmHg (glaucoma patients); 17±2.8 to 21±2.4 mmHg (normal individuals)). IOP dropped back to baseline values within two minutes after returning to a sitting position. Overall, IOP rise was not significantly different between glaucoma and normal subjects (P = 0.813), all though glaucoma eyes tended to have measurements 2 mm Hg higher on average. Conclusions Yoga exercises with head-down positions were associated with a rapid rise in IOP in glaucoma and healthy eyes. IOP returned to baseline values within 2 minutes. Future studies are warranted addressing whether yoga exercise associated IOP changes are associated with similar changes in cerebrospinal fluid pressure and whether they increase the risk of glaucoma progression. Trial Registration ClinicalTrials.gov #NCT01915680 PMID:26698309

  4. Real-Time Benchmark Suite

    1992-01-17

    This software provides a portable benchmark suite for real time kernels. It tests the performance of many of the system calls, as well as the interrupt response time and task response time to interrupts. These numbers provide a baseline for comparing various real-time kernels and hardware platforms.

  5. Effect of persistent high intraocular pressure on microstructure and hydraulic permeability of trabecular meshwork

    NASA Astrophysics Data System (ADS)

    Mei, Xi; Ren, Lin; Xu, Qiang; Zheng, Wei; Liu, Zhi-Cheng

    2015-05-01

    As the aqueous humor leaves the eye, it first passes through the trabecular meshwork (TM). Increased flow resistance in this region causes elevation of intraocular pressure (IOP), which leads to the occurrence of glaucoma. To quantitatively evaluate the effect of high IOP on the configuration and hydraulic permeability of the TM, second harmonic generation (SHG) microscopy was used to image the microstructures of the TM and adjacent tissues in control (normal) and high IOP conditions. Enucleated rabbit eyes were perfused at a pressure of 60 mmHg to achieve the high IOP. Through the anterior chamber of the eye, in situ images were obtained from different depths beneath the surface of the TM. Porosity and specific surface area of the TM in control and high IOP conditions were then calculated to estimate the effect of the high pressure on the permeability of tissue in different depths. We further photographed the histological sections of the TM and compared the in situ images. The following results were obtained in the control condition, where the region of depth was less than 55 μm with crossed branching beams and large pores in the superficial TM. The deeper meshwork is a silk-like tissue with abundant fluorescence separating the small size of pores. The total thickness of pathway tissues composed of TM and juxtacanalicular (JCT) is more than 100 μm. After putting a high pressure on the inner wall of the eye, the TM region progressively collapses and decreases to be less than 40 μm. Fibers of the TM became dense, and the porosity at 34 μm in the high IOP condition is comparable to that at 105 μm in the control condition. As a consequent result, the permeability of the superficial TM decreases rapidly from 120 μm2 to 49.6 μm2 and that of deeper TM decreases from 1.66 μm2 to 0.57 μm2. Heterogeneity reflected by descent in permeability reduces from 12.4 μm of the control condition to 3.74 μm of the high IOP condition. The persistently high IOP makes the TM

  6. Achieving Controlled Intraocular Pressure and Restoration of Vision Following Proactive Treatment of Total Choroidal Detachment Due to Endocyclophotocoagulation.

    PubMed

    Al-Asbali, Tariq

    2016-01-01

    Ocular hypotony due to choroidal detachment (CD) following endocyclophotocoagulation (ECP) is transient. If hypotony lasts for more than 1 week, it could affect vision. This is a case of refractory glaucoma following cataract surgery that was managed by ECP. We drained subchoroidal fluid as CD did not resolve after 1 week. After 5 months, the intraocular pressure was restored to 16 mmHg with one topical glaucoma medication, uncorrected vision improved to 20/300, and with aphakic soft contact lens, it was 20/50. Ophthalmologists facing such complications need not panic and manage hypotony, and the prognosis of such intervention seems to be promising. PMID:27555714

  7. Achieving Controlled Intraocular Pressure and Restoration of Vision Following Proactive Treatment of Total Choroidal Detachment Due to Endocyclophotocoagulation

    PubMed Central

    Al-Asbali, Tariq

    2016-01-01

    Ocular hypotony due to choroidal detachment (CD) following endocyclophotocoagulation (ECP) is transient. If hypotony lasts for more than 1 week, it could affect vision. This is a case of refractory glaucoma following cataract surgery that was managed by ECP. We drained subchoroidal fluid as CD did not resolve after 1 week. After 5 months, the intraocular pressure was restored to 16 mmHg with one topical glaucoma medication, uncorrected vision improved to 20/300, and with aphakic soft contact lens, it was 20/50. Ophthalmologists facing such complications need not panic and manage hypotony, and the prognosis of such intervention seems to be promising. PMID:27555714

  8. Monothiocarbamates Strongly Inhibit Carbonic Anhydrases in Vitro and Possess Intraocular Pressure Lowering Activity in an Animal Model of Glaucoma.

    PubMed

    Vullo, Daniela; Durante, Mariaconcetta; Di Leva, Francesco Saverio; Cosconati, Sandro; Masini, Emanuela; Scozzafava, Andrea; Novellino, Ettore; Supuran, Claudiu T; Carta, Fabrizio

    2016-06-23

    A series of monothiocarbamates (MTCs) were prepared from primary/secondary amines and COS as potential carbonic anhydrase (CA, EC 4.2.1.1) inhibitors, using the dithiocarbamates, the xanthates, and the trithiocarbonates as lead compounds. The MTCs effectively inhibited the pharmacologically relevant human (h) hCAs isoforms I, II, IX, and XII in vitro and showed KIs spanning between the low and medium nanomolar range. By means of a computational study, the MTC moiety binding mode on the CAs was explained. Furthermore, a selection of MTCs were evaluated in a normotensive glaucoma rabbit model for their intraocular pressure (IOP) lowering effects and showed interesting activity. PMID:27253845

  9. Posterior fixation keratoprostheses and mechanical biocompatibility: determination of critical intraocular pressure causing aqueous humor leak and/or keratoprosthesis extrusion

    NASA Astrophysics Data System (ADS)

    Tahi, Hassan; Duchesne, Bernard; Parel, Jean-Marie A.; Nose, Izuru; Denham, David B.; Villain, Franck L.; Lacombe, Emmanuel

    1997-05-01

    The effect of increased intraocular pressure (IOP) in human cadaver eyes implanted with posterior fixation keratoprosthesis was evaluated. Experiments were carried out with six fresh pairs of human cadaver eyes. One eye of each pair was implanted with a PCL-5 keratoprosthesis (8.60 mm diameter with an optic of 5.60 nm diameter) and the contralateral eye was used as a control. The keratoprosthesis was inserted through a 6 mm diameter opening trephined in the cornea. The resistance of the implanted eye to pressure on `aqueous humor' leak and/or keratoprosthesis extrusion was tested by infusing water at a constant flow of 60 mmHg/second into the anterior chamber. IOP variations were recorded with a transducer connected to a computer. IOP could be increased up to 1520 to 2324 mmHg before aqueous humor leaks occurred. Leaks were always located at the keratoprosthesis-cornea interface. No prosthesis extrusion was observed. Implanted eyes that did not leak aqueous and control eyes tore at the sclera. All posterior fixation keratoprostheses implanted eyes resisted more than 100 times the normal physiological intraocular pressure and on this standpoint is safe. Additional experiments were needed to assess the influence of suture fixation and wound healing in an animal model.

  10. Increased intraocular pressure on the first postoperative day following resident-performed cataract surgery

    PubMed Central

    Kim, J Y; Jo, M-W; Brauner, S C; Ferrufino-Ponce, Z; Ali, R; Cremers, S L; An Henderson, B

    2011-01-01

    Purpose The aim of this study was to investigate the incidence of intraocular pressure (IOP) elevation after resident-performed cataract surgery and to determine variables, which influence postoperative day 1 (POD1) IOP. Methods In all, 1111 consecutive cataract surgeries performed only by training residents between 1 July 2001 and 30 June 2006 were included. Elevated IOP was defined as ≥23 mm Hg. Surgeries were classified according to the presence of POD1-IOP elevation. Fisher's exact test and Student t-test were used to compare both groups. Multivariate analyses using generalized estimating equations were performed to investigate predictor variables associated with POD1-IOP elevation. Results The average preoperative IOP was 16.0±3.2 mm Hg and the average POD1-IOP was 19.3±7.1 mm Hg, reflecting a significant increase in IOP (P<0.001, paired t-test). The incidence of POD1-IOP elevation ≥23 mm Hg was 22.0% (244/1111). Presence of glaucoma and ocular hypertension, higher preoperative IOP, and longer axial length were frequently encountered variables in the POD1-IOP elevation group (all P<0.05). Using a multivariate analysis, presence of glaucoma (P=0.004, OR=2.38; 95% confidence interval (95% CI)=1.31–4.30), presence of ocular hypertension (P=0.003, OR=6.09; 95% CI=1.81–20.47), higher preoperative IOP (P<0.001, OR=3.73; 95% CI=1.92–7.25), and longer axial length (P=0.01, OR=1.15; 95% CI=1.03–1.29) were significant predictive factors for POD1-IOP elevation. Conclusions IOP elevation on the first postoperative day following resident-performed cataract surgery occurred frequently (22.0%). Increased early postoperative IOP was associated with presence of glaucoma and ocular hypertension, higher preoperative IOP, and longer axial length. PMID:21527959

  11. Assessment of the central corneal thickness and intraocular pressure in premature and full-term newborns

    PubMed Central

    Muslubas, Isil Bahar Sayman; Oral, Ayse Yesim Aydın; Cabi, Cemalettin; Caliskan, Sinan

    2014-01-01

    Purpose: To assess the central corneal thickness (CCT) and intraocular pressure (IOP) in premature and full-term newborns. Materials and Methods: In this study, we evaluated measurements of CCT and IOP in 45 premature and 45 full-term newborns. IOP was determined with topical anesthesia using a Tono-Pen AVIA, applanation tonometer and a wire lid retractor in premature newborns undergoing screening for retinopathy. Full-term newborns were used as a control group. CCT was determined with a portable pachymeter after IOP measurements had been made in both groups. Because there was high correlation of CCT and IOP between right and left eyes, only the right eye data were used for further analyses. Results: The mean gestational age was 31.5 ± 2.7 weeks (ranging 25-35 weeks) and the mean age at measurement after birth was respectively 36.3 ± 0.9 weeks (ranging 33-37 weeks) in premature newborns and 38.2 ± 0.7 weeks (ranging 38-41 weeks) and 42 ± 2.2 weeks (ranging 39-46 weeks) in full-term newborns. The mean IOP was 16.2 ± 2.7 mmHg (ranging 10-22 mmHg) in premature and 16.6 ± 2.3 mmHg (ranging 10-22 mmHg) in full-term newborns. The mean CCT was found 600 ± 50 μm (ranging 515-790 μm) in the premature group and 586 ± 48 μm (ranging 475-730 μm) in the full-term group. Mean CCT was greater in premature newborns than in full-term newborns, but the difference between groups was not statistically significant (P = 0.7). Mean IOP measurement in two groups was found very similar and the difference also was not statistically significant (P = 0.27). There was no correlation between IOP and CCT, gestational age, gestational weight, age at measurement, weight at measurement neither right nor left eye in both groups in multiple regression analysis. Conclusion: We found that premature infants have slightly thicker corneas but no high IOP measurements than full-term newborns. It could be concluded that in premature at the mean gestational age of 36 weeks CCT is not different

  12. Latrunculin B Reduces Intraocular Pressure in Human Ocular Hypertension and Primary Open-Angle Glaucoma

    PubMed Central

    Rasmussen, Carol A.; Kaufman, Paul L.; Ritch, Robert; Haque, Reza; Brazzell, R. Kim; Vittitow, Jason L.

    2014-01-01

    Purpose To evaluate the safety, tolerability, and intraocular pressure (IOP)-lowering effect of Latrunculin-B (Lat-B), a marine macrolide that disrupts the actin cytoskeleton, in patients with ocular hypertension (OHT) or early primary open-angle glaucoma (POAG). Methods In this Phase I, multicenter, double-masked, randomized, placebo-controlled, ascending-dose study, subjects with bilateral OHT or early POAG (>22 mm Hg) received one of four concentrations of INS115644 (Lat-B ophthalmic solutions, 0.005%, 0.01%, 0.02%, or 0.05%) in one eye over 3 days (5 single-dose instillations, separated by 12 hours). One eye was randomly assigned to active drug, the other to placebo. IOP was measured prior to treatment initiation (day 0) and on days 1 and 3. Results Baseline IOPs were 22.9 ± 2.4 mm Hg and 23.5 + 3.1 mm Hg in the 0.02% and 0.05% dose groups, respectively. At 4 hours post instillation of the first dose, 0.02% INS115644 reduced IOP from baseline (mean ± SE) by 3.8 ± 0.7 mm Hg (P = 0.002) and 0.05% by 3.9 ± 1.0 mm Hg (P = 0.004). A maximum IOP decrease of 24% was noted at 4 hours after the fifth instillation of 0.02%. Adjusting for diurnal baseline and IOP in the contralateral, placebo-treated eye, the maximal 12-hour hypotensive effect was 4.0 ± 0.5 mm Hg (adjusted mean ± SE), a 17% decrease, following the fifth instillation of 0.02% (day 3). Adverse events were few and consisted mainly of mild redness, irritation, and a transient, clinically insignificant increase (≤2.5%) in central corneal thickness. Conclusions In OHT or POAG patients, twice daily Lat-B significantly lowered IOP compared with contralateral, placebo-treated eyes, with few and mild ocular adverse events. Translational Relevance Lat-B may be a potential therapeutic agent for glaucoma. PMID:25237590

  13. Optic nerve head and intraocular pressure in the guinea pig eye.

    PubMed

    Ostrin, Lisa A; Wildsoet, Christine F

    2016-05-01

    The guinea pig is becoming an increasingly popular model for studying human myopia, which carries an increased risk of glaucoma. As a step towards understanding this association, this study sought to characterize the normal, developmental intraocular pressure (IOP) profiles, as well as the anatomy of the optic nerve head (ONH) and adjacent sclera of young guinea pigs. IOP was tracked in pigmented guinea pigs up to 3 months of age. One guinea pig was imaged in vivo with OCT and one with a fundus camera. The eyes of pigmented and albino guinea pigs (ages 2 months) were enucleated and sections from the posterior segment, including the ONH and surrounding sclera, processed for histological analyses - either hematoxylin and eosin (H&E) staining of paraffin embedded, sectioned tissue (n = 1), or cryostat sectioned tissue, processed for immunohistochemistry (n = 3), using primary antibodies against collagen types I-V, elastin, fibronectin and glial fibrillary acidic protein (GFAP). Transmission and scanning electron microscopy (TEM, SEM) studies of ONHs were also undertaken (n = 2 & 5 respectively). Mean IOPs ranged from 17.33 to 22.7 mmHg, increasing slightly across the age range studied, and the IOPs of individual animals also exhibited diurnal variations, peaking in the early morning (mean of 25.8, mmHg, ∼9 am), and decreasing across the day. H&E-stained sections showed retinal ganglion cell axons organized into fascicles in the prelaminar and laminar region of the ONHs, with immunostained sections revealing collagen types I, III, IV and V, as well as elastin, GFAP and fibronectin in the ONHs. SEM revealed a well-defined lamina cribrosa (LC), with radially-oriented collagen beams. TEM revealed collagen fibrils surrounding non-myelinated nerve fiber bundles in the LC region, with myelination and decreased collagen posterior to the LC. The adjacent sclera comprised mainly crimped collagen fibers in a crisscross arrangement. Both the sclera and LC were

  14. Real-time flutter identification

    NASA Technical Reports Server (NTRS)

    Roy, R.; Walker, R.

    1985-01-01

    The techniques and a FORTRAN 77 MOdal Parameter IDentification (MOPID) computer program developed for identification of the frequencies and damping ratios of multiple flutter modes in real time are documented. Physically meaningful model parameterization was combined with state of the art recursive identification techniques and applied to the problem of real time flutter mode monitoring. The performance of the algorithm in terms of convergence speed and parameter estimation error is demonstrated for several simulated data cases, and the results of actual flight data analysis from two different vehicles are presented. It is indicated that the algorithm is capable of real time monitoring of aircraft flutter characteristics with a high degree of reliability.

  15. Efficacy of combined cataract extraction and endoscopic cyclophotocoagulation for the reduction of intraocular pressure and medication burden

    PubMed Central

    Roberts, Sammie J.; Mulvahill, Matthew; SooHoo, Jeffrey R.; Pantcheva, Mina B.; Kahook, Malik Y.; Seibold, Leonard K.

    2016-01-01

    AIM To report on the efficacy of combined endoscopic cyclophotocoagulation (ECP) and phacoemulsification cataract extraction (PCE) with intraocular lens placement for reduction of intraocular pressure (IOP) and medication burden in glaucoma. METHODS A retrospective case review of 91 eyes (73 patients) with glaucoma and cataract that underwent combined PCE/ECP surgery was performed. Baseline demographic and ocular characteristics were recorded, as well as intraocular pressure, number of glaucoma medications, and visual acuity postoperatively with 12-month follow-up. Treatment failure was defined as less than 20% reduction in IOP from baseline on two consecutive visits (at 1, 3, 6, or 12mo postoperatively), IOP ≥21 mm Hg or ≤5 mm Hg on two consecutive visits, or additional glaucoma surgery performed within 12mo after PCE/ECP. RESULTS Overall, mean medicated IOP was reduced from 16.65 mm Hg at baseline to 13.38 mm Hg at 12mo (P<0.0001). Mean number of glaucoma medications was reduced from 1.88 medications at baseline to 1.48 medications at 12mo (P=0.0003). At 3mo postoperatively, the success rate was 73.6% (95%CI: 63.3, 81.5), 57.1% at 6mo (95% CI: 46.3, 66.6), and 49.7% at 12mo (95%CI: 38.9, 59.6). Patient demographic characteristics were not associated with treatment success. The only ocular characteristic associated with treatment success was a higher baseline IOP. CONCLUSION Combined PCE/ECP surgery is an effective surgical option for the reduction of IOP and medication burden in glaucoma patients. Patients with higher baseline IOP levels are most likely to benefit from this procedure. PMID:27275423

  16. Combined ab interno trabeculotomy and lens extraction: a novel management option for combined uveitic and chronic narrow angle raised intraocular pressure.

    PubMed

    Lin, Siying; Gupta, Bhaskar; Rossiter, Jonathan

    2016-02-01

    Minimally invasive glaucoma surgery is a developing area that has the potential to replace traditional glaucoma surgery, with its known risk profile, but at present there are no randomised controlled data to validate its use. We report on a case where sequential bilateral combined ab interno trabeculotomy and lens extraction surgery was performed on a 45-year-old woman with combined uveitic and chronic narrow angle raised intraocular pressure. Maximal medical management alone could not control the intraocular pressure. At 12-month follow-up, the patient had achieved stable intraocular pressure in both eyes on a combination of topical ocular antiglaucomatous and steroid therapies. This case demonstrates the effectiveness of trabecular meshwork ablation via ab interno trabeculotomy in a case of complex mixed mechanism glaucoma.

  17. Real-time software receiver

    NASA Technical Reports Server (NTRS)

    Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

    2007-01-01

    A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

  18. Real-time software receiver

    NASA Technical Reports Server (NTRS)

    Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

    2006-01-01

    A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

  19. Real-time vision systems

    SciTech Connect

    Johnson, R.; Hernandez, J.E.; Lu, Shin-yee

    1994-11-15

    Many industrial and defence applications require an ability to make instantaneous decisions based on sensor input of a time varying process. Such systems are referred to as `real-time systems` because they process and act on data as it occurs in time. When a vision sensor is used in a real-time system, the processing demands can be quite substantial, with typical data rates of 10-20 million samples per second. A real-time Machine Vision Laboratory (MVL) was established in FY94 to extend our years of experience in developing computer vision algorithms to include the development and implementation of real-time vision systems. The laboratory is equipped with a variety of hardware components, including Datacube image acquisition and processing boards, a Sun workstation, and several different types of CCD cameras, including monochrome and color area cameras and analog and digital line-scan cameras. The equipment is reconfigurable for prototyping different applications. This facility has been used to support several programs at LLNL, including O Division`s Peacemaker and Deadeye Projects as well as the CRADA with the U.S. Textile Industry, CAFE (Computer Aided Fabric Inspection). To date, we have successfully demonstrated several real-time applications: bullet tracking, stereo tracking and ranging, and web inspection. This work has been documented in the ongoing development of a real-time software library.

  20. Study of the effect of distance and misalignment between magnetically coupled coils for wireless power transfer in intraocular pressure measurement.

    PubMed

    Rendon-Nava, Adrian E; Díaz-Méndez, J Alejandro; Nino-de-Rivera, Luis; Calleja-Arriaga, Wilfrido; Gil-Carrasco, Felix; Díaz-Alonso, Daniela

    2014-01-01

    An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them. PMID:25097887

  1. Study of the Effect of Distance and Misalignment between Magnetically Coupled Coils for Wireless Power Transfer in Intraocular Pressure Measurement

    PubMed Central

    Rendon-Nava, Adrian E.; Díaz-Méndez, J. Alejandro; Nino-de-Rivera, Luis; Calleja-Arriaga, Wilfrido; Gil-Carrasco, Felix; Díaz-Alonso, Daniela

    2014-01-01

    An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them. PMID:25097887

  2. The impact of acute dynamic exercise on intraocular pressure: role of the beta 2-adrenergic receptor polymorphism.

    PubMed

    Güngör, K; Beydaği, H; Bekir, N; Arslan, C; Süer, C; Erbağci, I; Ergenoğlu, T; Aynacioğlu, A S

    2002-01-01

    Effects of mutations in the beta 2-adrenergic receptor (beta 2AR) gene on intraocular pressure (IOP), in response to acute dynamic exercise, were investigated in 19 healthy males (age 22.6 +/- 2.8 years). Intraocular pressures were measured pre- and post-exercise. Weight, height, body mass index, and maximal oxygen (VO2max) uptake were recorded and subjects were genotyped for Arg16Gly, Gln27Glu and Thr164Ile mutations of the beta 2AR gene. Post-exercise, reductions in mean IOP values were found in 16 subjects with the Gly16Gly and Arg16Gly genotypes, but these values remained low in the eight patients with the Gly16Gly genotype 3 h post-exercise, whereas they returned to baseline within 1 h in the eight subjects with the Arg16Gly genotype. beta 2AR stimulation during exercise could be an important regulator of IOP response and determining beta 2AR polymorphisms may improve understanding of pathogenesis and treatment selection in ophthalmic diseases, e.g. glaucoma.

  3. Rational use of the fixed combination of dorzolamide – timolol in the management of raised intraocular pressure and glaucoma

    PubMed Central

    Yeh, Jason; Kravitz, Daniel; Francis, Brian

    2008-01-01

    Glaucoma is a multifactorial optic neuropathy in which the main therapeutic target is lowering of intraocular pressure (IOP) in order to retard the progression of existing structural and functional damage. The three mainstays of treatment are pharmacologic, laser, and surgical. The primary standard therapy in patients with open-angle glaucoma or ocular hypertension is topical medication. When monotherapy does not adequately lower the intraocular pressure, one or more agents are added or substituted. Combination pharmacotherapy such as Cosopt® is available to improve efficacy and simplify medication regimen. A fixed combination of two ocular hypotensive drugs (the carbonic anhydrase inhibitor dorzolamide and the beta-adrenoceptor antagonist timolol), Cosopt® is indicated for the treatment of elevated IOP in patients with open-angle glaucoma or ocular hypertension insufficiently responsive to topical beta-adrenoceptor antagonist monotherapy. Compared with concomitant therapy with the individual components, the primary advantage of fixed combination dorzolamide – timolol is convenience, which may also improve compliance. Clinical trials have demonstrated that the fixed combination dorzolamide – timolol is safe, effective and generally well tolerated in lowering IOP in patients with open angle glaucoma or ocular hypertension, including individuals uncontrolled on beta-adrenoceptor antagonist or other monotherapy. PMID:19668730

  4. The effect of changing intraocular pressure on the corneal and scleral curvatures in the fresh porcine eye

    PubMed Central

    Pierscionek, B K; Asejczyk‐Widlicka, M; Schachar, R A

    2007-01-01

    Aim To measure corneal and scleral radii of curvature in response to intraocular pressure (IOP). Methods Using digital photographic profile images of 16 fresh porcine eyes, the curvatures of the cornea and sclera were determined in response to five consecutive incremental 100 μl saline intravitreal injections. IOP was measured and ocular rigidity calculated. Elastic moduli of the cornea and sclera were estimated. Results Intraocular pressure and the radius of curvature of the sclera increased linearly with increasing volume. There was no statistical change in corneal curvature. The elasticity of the cornea and sclera was constant during the 15–50 mm Hg increase in IOP. The estimated range of the elastic moduli of the cornea and sclera were, respectively 0.07–0.29 MPa and 0.2 MPa to 0.5 MPa. The scleral rigidity ranged from 0.0017 to 0.0022. Conclusions The elastic moduli of the cornea and sclera are independent of IOP. The modulus of elasticity of the sclera is higher than that of the cornea. Elevation of IOP changes the curvature of the sclera but not that of the cornea. Porcine scleral rigidity is similar to human scleral rigidity. Scleral curvature could be a novel method for measuring IOP. PMID:17151057

  5. Intraocular pressure measurement after penetrating keratoplasty: minified Goldmann applanation tonometer, pneumatonometer, and Tono-Pen versus manometry.

    PubMed Central

    Ménage, M J; Kaufman, P L; Croft, M A; Landay, S P

    1994-01-01

    The accuracy of intraocular pressure measurement with the minified Goldmann applanation tonometer, the pneumatonometer, and the Tono-Pen tonometer were compared in post-mortem human eyes which had undergone penetrating keratoplasty. Enucleated post-mortem human eyes underwent same sized (7.75 mm) or 0.5 mm oversized (8.25 mm) autologous penetrating keratoplasty. Intraocular pressure was then set and measured manometrically while being determined successively with each tonometer over the range of 0-65 mm Hg. Linear regression analysis comparing tonometric and manometric readings showed: (1) minified Goldmann applanation tonometer-slope 0.985 and 0.944, intercept 1.64 and 2.55 mm Hg, correlation coefficient 0.99 and 0.99 in same sized and oversized grafted eyes respectively; (2) pneumatonometer-slope 1.008 and 0.990, intercept 3.37 and 3.69 mm Hg, correlation coefficient 0.99 and 0.98; (3) Tono-Pen-slope 1.061 and 1.002, intercept 5.01 and 4.06 mm Hg, correlation coefficient 0.97 and 0.98. We concluded that the minified Goldmann applanation tonometer is as accurate or more accurate than the pneumatonometer and the Tono-Pen in post-mortem post-keratoplasty human eyes, and may be an economical, convenient alternative to the latter two instruments in clinical practice. PMID:7947545

  6. sCD44 overexpression increases intraocular pressure and aqueous outflow resistance

    PubMed Central

    Giovingo, Michael; Nolan, Michael; McCarty, Ryan; Pang, Iok-Hou; Clark, Abbot F.; Beverley, Rachel M.; Schwartz, Steven; Stamer, W. Daniel; Walker, Loyal; Grybauskas, Algis; Skuran, Kevin; Kuprys, Paulius V.; Yue, Beatrice Y.J.T.

    2013-01-01

    Purpose CD44 plays major roles in multiple physiologic processes. The ectodomain concentration of the CD44 receptor, soluble CD44 (sCD44), is significantly increased in the aqueous humor of primary open-angle glaucoma (POAG). The purpose of this study was to determine if adenoviral constructs of CD44 and isolated 32-kDa sCD44 change intraocular pressure (IOP) in vivo and aqueous outflow resistance in vitro. Methods Adenoviral constructs of human standard CD44 (Ad-CD44S), soluble CD44 (Ad-sCD44), and empty viral cDNA were injected into the vitreous of BALB/cJ mice, followed by serial IOP measurements. Overexpression of CD44S and sCD44 was verified in vitro by enzyme-linked immunosorbent assay (ELISA) and western blot analysis. Anterior segments of porcine eyes were perfused with the isolated sCD44. sCD44-treated human trabecular meshwork (TM) cells and microdissected porcine TM were examined by confocal microscopy and Optiprep density gradient with western blot analysis to determine changes in lipid raft components. Results Intravitreous injection of adenoviral constructs with either Ad-CD44S or Ad-sCD44 vectors caused prolonged ocular hypertension in mice. Eight days after vector injection, Ad-CD44S significantly elevated IOP to 28.3±1.2 mmHg (mean±SEM, n=8; p<0.001); Ad-sCD44 increased IOP to 18.5±2.6 mmHg (n=8; p<0.01), whereas the IOP of uninjected eyes was 12.7±0.2 mmHg (n=16). The IOP elevation lasted more than 50 days. Topical administration of a γ-secretase inhibitor normalized Ad-sCD44-induced elevated IOP. sCD44 levels were significantly elevated in the aqueous humor of Ad-CD44S and Ad-sCD44 eyes versus contralateral uninjected eyes (p<0.01). Anterior segment perfusion of isolated 32-kDa sCD44 significantly decreased aqueous outflow rates. Co-administration of isolated sCD44 and CD44 neutralizing antibody or of γ-secretase inhibitor significantly enhanced flow rates. sCD44-treated human TM cells displayed cross-linked actin network formation

  7. Cataract Surgery combined with excimer laser trabeculotomy to lower intraocular pressure: effectiveness dependent on preoperative IOP

    PubMed Central

    2013-01-01

    Background Cataract surgery combined with excimer laser trabeculotomy (phaco-ELT) can reduce intraocular pressure (IOP). The aim of this study was to evaluate the effect of phaco-ELT on IOP in patients as a function of preoperative IOP. Methods Patients with open-angle glacuoma or ocular hypertension who received phaco-ELT between 01/2008 and 10/2009 were included. Patients were assigned based on preoperative IOP either to the study group (≤21 mmHg) or control group (>21 mmHg) in this IRB-approved, prospective, consecutive case series. Visual Acuity, IOP, and number of anti-glaucoma drugs (AGD) were recorded at baseline and 12 months after phaco-ELT. Any postoperative complications were also recorded. Results 64 eyes of 64 patients (76.5 ± 9.4 years) were included. Baseline IOP was 19.8 ± 5.3 mmHg (AGD 2.4 ± 1.1) for all eyes, 16.5 ± 2.9 mmHg (AGD 2.5 ± 1.0) for the study group, and 25.8 ± 2.9 mmHg (AGD 2.2 ± 1.4) for the control group. Across the two groups, IOP was reduced by 4.5 ± 5.9 mmHg (-23.0%, p < 0.001) and AGD by 0.9 ± 1.5 (-38.9%, p < 0.001). For the study group IOP was reduced by 1.9 ± 4.4 mmHg (-11. 5 %, p = 0.012) and AGD by 1.1 ± 1.4 (-42.9%, p < 0.001), and for the control group by 9.5 ± 5.4 mmHg (-36.6%, p < 0.001) and AGD by 0.7 ± 1.6 (-29.5%, p = 0.085). There were no serious postoperative complications such as endophthalmitis, significant hyphema, or a severe fibrinous reaction of the anterior chamber. Conclusions IOP remained significantly reduced from baseline 12 months after phaco-ELT regardless of preoperative IOP levels, with no major complications. The IOP reduction remained constant over the entire follow-up. Hence, phaco-ELT can be considered in glaucoma and ocular hypertensive patients whenever cataract surgery is performed, in order to further reduce IOP or to reduce the requirement for IOP-reducing medications. PMID:23799932

  8. Real-Time Moire Holography

    NASA Astrophysics Data System (ADS)

    Soares, O. D. D.; Lage, A. I. V. S.

    1986-08-01

    Interferometric techniques including hologrametry, both classical and electronic, present high sensitivity making difficult its practical use in real-time. The introduction of the differencial concept as moire evaluation techniques permits to use with advantage an arbitrary reference pattern within the correlation range. The carrier spatial spectrum can be directly the interferogram fringe pattern instead of the original interference pattern of wavelength dimensional scale. A moire techniques is in itself an optical processing method reducing evaluation time which is advantageous when real-time response is desired from hybrid metrological systems. The moire evaluation is performed via a dynamical digital memory that executes arithmetic operations on two frames temporally in sequence, at TV rate. These characteristics of the moire evaluation techniques can be implemented on a real-time holographic (or speckle based) hybrid system with great practical advantage for dynamical studies.

  9. Real-Time Optical Monitoring and Simulations of Gas Phase Kinetics in InN Vapor Phase Epitaxy at High Pressure

    NASA Technical Reports Server (NTRS)

    Dietz, Nikolaus; Woods, Vincent; McCall, Sonya D.; Bachmann, Klaus J.

    2003-01-01

    Understanding the kinetics of nucleation and coalescence of heteroepitaxial thin films is a crucial step in controlling a chemical vapor deposition process, since it defines the perfection of the heteroepitaxial film both in terms of extended defect formation and chemical integrity of the interface. The initial nucleation process also defines the film quality during the later stages of film growth. The growth of emerging new materials heterostructures such as InN or In-rich Ga(x)In(1-x)N require deposition methods operating at higher vapor densities due to the high thermal decomposition pressure in these materials. High nitrogen pressure has been demonstrated to suppress thermal decomposition of InN, but has not been applied yet in chemical vapor deposition or etching experiments. Because of the difficulty with maintaining stochiometry at elevated temperature, current knowledge regarding thermodynamic data for InN, e.g., its melting point, temperature-dependent heat capacity, heat and entropy of formation are known with far less accuracy than for InP, InAs and InSb. Also, no information exists regarding the partial pressures of nitrogen and phosphorus along the liquidus surfaces of mixed-anion alloys of InN, of which the InN(x)P(1-x) system is the most interesting option. A miscibility gap is expected for InN(x)P(1-x) pseudobinary solidus compositions, but its extent is not established at this point by experimental studies under near equilibrium conditions. The extension of chemical vapor deposition to elevated pressure is also necessary for retaining stoichiometric single phase surface composition for materials that are characterized by large thermal decomposition pressures at optimum processing temperatures.

  10. Real-time measurements of temperature, pressure and moisture profiles in High-Performance Concrete exposed to high temperatures during neutron radiography imaging

    SciTech Connect

    Toropovs, N.; Lo Monte, F.; Wyrzykowski, M.; Weber, B.; Sahmenko, G.; Vontobel, P.; Felicetti, R.; Lura, P.

    2015-02-15

    High-Performance Concrete (HPC) is particularly prone to explosive spalling when exposed to high temperature. Although the exact causes that lead to spalling are still being debated, moisture transport during heating plays an important role in all proposed mechanisms. In this study, slabs made of high-performance, low water-to-binder ratio mortars with addition of superabsorbent polymers (SAP) and polypropylene fibers (PP) were heated from one side on a temperature-controlled plate up to 550 °C. A combination of measurements was performed simultaneously on the same sample: moisture profiles via neutron radiography, temperature profiles with embedded thermocouples and pore pressure evolution with embedded pressure sensors. Spalling occurred in the sample with SAP, where sharp profiles of moisture and temperature were observed. No spalling occurred when PP-fibers were introduced in addition to SAP. The experimental procedure described here is essential for developing and verifying numerical models and studying measures against fire spalling risk in HPC.

  11. Real Time Sonic Boom Display

    NASA Technical Reports Server (NTRS)

    Haering, Ed

    2014-01-01

    This presentation will provide general information about sonic boom mitigation technology to the public in order to supply information to potential partners and licensees. The technology is a combination of flight data, atmospheric data and terrain information implemented into a control room real time display for flight planning. This research is currently being performed and as such, any results and conclusions are ongoing.

  12. Utility of the Tono-Pen in Measuring Intraocular Pressure in Trinidad: A Cross-sectional Study

    PubMed Central

    Billy, A; David, PE; Mahabir, AK; Seerattan, CP; Street, JM; Walcott, VD; Yarna, RJ; Murray, DC; Maharaj, RG

    2015-01-01

    ABSTRACT Aim: To determine the sensitivity and specificity of the Reichert™ Tono-Pen AVIA® when used by novice medical students in an ethnically diverse population in Trinidad. Subject and Methods: Participants were residents of Trinidad between the ages of 20 and 90 years attending the Ophthalmology Clinic at the Eric Williams Medical Sciences Complex (EWMSC). Intraocular pressure (IOP) was measured using the Goldmann applanation tonometer (the gold standard) for ophthalmology clinic patients as part of their routine care. Intraocular pressure measurements were then taken using the Tono-Pen. Results: One hundred persons participated, consisting of Indo-Trinidadians (55%), Afro-Trinidadians (36%), Mixed (8%) and 1% of Caucasian descent. Fourteen per cent reported a diagnosis of glaucoma with 70.6% of these being of African descent. One hundred and ninety-eight readings of IOP were taken. At a cut-off point of 21 mmHg, there were nine true positives, four false positives, seven false negatives and 178 true negatives. The sensitivity and specificity were found to be 56.3% (95% CI 33.2, 76.9) and 97.8% (95% CI 94.5, 99.1), respectively. The positive predictive value was calculated as 69.2% (95% CI 42.4, 87.3) while the negative predictive value was 96.2% (95% CI 92.4, 98.2). The prevalence of elevated IOP in this population was 8.1% (95% CI 4.8, 13.0). The likelihood ratio of a positive result was calculated to be 25.6 (95% CI 8.6, 73.9). Conclusion: The high specificity and negative predictive value suggests that the Tono-Pen can be used with minimal training, and can prove beneficial at the primary care level in the exclusion of increased IOP in an ethnically diverse high-risk Caribbean population. PMID:26624589

  13. Comparison of dielectric barrier discharge, atmospheric pressure radiofrequency-driven glow discharge and direct analysis in real time sources for ambient mass spectrometry of acetaminophen

    NASA Astrophysics Data System (ADS)

    Kratzer, Jan; Mester, Zoltán; Sturgeon, Ralph E.

    2011-08-01

    Three plasma-based ambient pressure ion sources were investigated; laboratory constructed dielectric barrier and rf glow discharges, as well as a commercial corona discharge (DART source). All were used to desorb and ionize a model analyte, providing sampling techniques for ambient mass spectrometry (MS). Experimental parameters were optimized to achive highest signal for acetaminophen as the analyte. Insight into the mechanisms of analyte desorption and ionization was obtained by means of emission spectrometry and ion current measurements. Desorption and ionization mechanisms for this analyte appear to be identical for all three plasma sources. Emission spectra differ only in the intensities of various lines and bands. Desorption of solid analyte requires transfer of thermal energy from the plasma source to sample surface, in the absence of which complete loss of MS response occurs. For acetaminophen, helium was the best plasma gas, providing 100- to 1000-fold higher analyte response than with argon or nitrogen. The same trend was also evident with background ions (protonated water clusters). MS analyte signal intensity correlates with the ion density (expressed as ion current) in the plasma plume and with emission intensity from excited state species in the plasma. These observations support an ionization process which occurs via proton transfer from protonated water clusters to analyte molecules.

  14. Real-time tritium imaging

    SciTech Connect

    Malinowski, M.E.

    1981-09-15

    A real-time image of a tritium-containing titanium film has been made by detecting the secondary electrons produced by tritium ..beta.. decay with a simple two-element electrostatic lens and microchannel plate image intensifier. The obtained image indicates that a resolution of better than 100 ..mu..m is currently obtainable and suggests that image magnification to enhance resolution should be possible.

  15. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  16. [Real time 3D echocardiography].

    PubMed

    Bauer, F; Shiota, T; Thomas, J D

    2001-07-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients. PMID:11494630

  17. Real-time exploitation system

    NASA Astrophysics Data System (ADS)

    Riedel, Richard D.

    1998-11-01

    The proliferation and technology advances of digital sensors for reconnaissance imaging require a commensurate increase in the productivity of ground-based exploitation system to process the increased volume of remotely-sensed data. Systems to support this level of production, themselves, must have significantly reduced development and life-cycle costs from previously installed systems. For cost, growth, and integration advantages, reconnaissance exploitation systems should be designed to maximize Commercial-Off-The-Shelf (COTS) hardware and software. As an example, the Real-Time Exploitation System is a state-of-the-art system for photo interpretation and exploitation of real-time digital reconnaissance imagery. Using COTS hardware, the system is able to receive imagery at rates greater than 80 Mpixels/sec; perform detailed interpretation, exploitation and report generation, and; disseminate reports to intelligence users over secure networks. New technologies have been applied in workflow management, database management, and user interfaces to provide the image analyst with superior analysis tools and access to other intelligence data sources. Photogrammetric functions are also provided for monoscopic and stereoscopic imagery. These functions provide greater geographic accuracy than is achievable in most reconnaissance exploitation systems. The Real-Time Exploitation System significantly reduces timelines for the analysis and report generation process, and significantly increases the quality and accuracy of reports.

  18. Comparison of brimonidine-timolol and dorzolamide-timolol in the management of intraocular pressure increase after phacoemulsification

    PubMed Central

    Turk, Adem; Ceylan, Osman Melih; Gokce, Gokcen; Borazan, Mehmet; Kola, Mehmet

    2015-01-01

    AIM To compare the effectiveness of brimonidine/timolol fixed combination (BTFC) and dorzolamide/timolol fixed combination (DTFC) in the management of short-term intraocular pressure (IOP) increase after phacoemulsification surgery. METHODS Eighty eyes of 80 patients undergoing phacoemulsification and intraocular lens (IOL) implantation were randomly assigned into three groups. Group 1 consisted of 28 eyes and represented the control group. Group 2 consisted of 25 eyes undergoing phacoemulsification surgery and BTFC was instilled at the end of surgery. Group 3 consisted of 27 eyes undergoing phacoemulsification surgery and DTFC was instilled at the end of surgery. IOP was measured preoperatively and 6, 24h and 1wk postoperatively. RESULTS There was no statistically significant difference in preoperative baseline IOP among the three groups (P=0.84). However, IOP was significantly lower in groups 2 and 3 compared to the control group (P<0.05 for all comparisons) at all postoperative visits. There was no significant difference between groups 2 and 3 at any visit. Eight eyes (28.6%) in the control group, two (8%) in Group 2 and one (3.7%) in Group 3 had IOP >25 mm Hg at 6h after surgery (P=0.008). However, IOP decreased and was >25 mm Hg in only one eye in each group at 24h after surgery. CONCLUSION BTFC and DTFC have similar effects in reducing increases in IOP after phacoemulsification surgery and can both be recommended for preventing IOP spikes after such surgery. PMID:26558206

  19. Development of a wireless intra-ocular pressure monitoring system for incorporation into a therapeutic glaucoma drainage implant

    NASA Astrophysics Data System (ADS)

    Kakaday, Tarun; Plunkett, Malcolm; McInnes, Steven; Li, Jim S. Jimmy; Voelcker, Nicolas H.; Craig, Jamie E.

    2008-12-01

    Glaucoma is a common cause of blindness. Wireless, continuous monitoring of intraocular pressure (IOP) is an important, unsolved goal in managing glaucoma. An IOP monitoring system incorporated into a glaucoma drainage implant (GDI) overcomes the design complexity associated with incorporating a similar system in a more confined space within the eye. The device consists of a micro-electro-mechanical systems (MEMS) based capacitive pressure sensor integrated with an inductor printed directly onto a polyimide printed circuit board (PCB). The device is designed to be incorporated onto the external plate of a therapeutic GDI. The resonance frequency changes as a function of IOP, and is tracked remotely using a spectrum analyzer. A theoretical model for the reader antenna was developed to enable maximal inductive coupling with the IOP sensor implant. Pressure chamber tests indicate that the sensor implant has adequate sensitivity in the IOP range with excellent reproducibility over time. Additionally, we show that sensor sensitivity does not change significantly after encapsulation with polydimethylsiloxane (PDMS) to protect the device from fluid environment. In vitro experiments showed that the signal measured wirelessly through sheep corneal and scleral tissue was adequate indicating potential for using the system in human subjects.

  20. Real-time flutter analysis

    NASA Technical Reports Server (NTRS)

    Walker, R.; Gupta, N.

    1984-01-01

    The important algorithm issues necessary to achieve a real time flutter monitoring system; namely, the guidelines for choosing appropriate model forms, reduction of the parameter convergence transient, handling multiple modes, the effect of over parameterization, and estimate accuracy predictions, both online and for experiment design are addressed. An approach for efficiently computing continuous-time flutter parameter Cramer-Rao estimate error bounds were developed. This enables a convincing comparison of theoretical and simulation results, as well as offline studies in preparation for a flight test. Theoretical predictions, simulation and flight test results from the NASA Drones for Aerodynamic and Structural Test (DAST) Program are compared.

  1. Real-time streamflow conditions

    USGS Publications Warehouse

    Graczyk, David J.; Gebert, Warren A.

    1996-01-01

    Would you like to know streamflow conditions before you go fishing in Wisconsin or in more distant locations? Real-time streamflow data throughout Wisconsin and the United States are available on the Internet from the U.S. Geological Survey. You can see if the stream you are interested in fishing is high due to recent rain or low because of an extended dry spell. Flow conditions at more than 100 stream-gaging stations located throughout Wisconsin can be viewed by accessing the Wisconsin District Home Page at: http://wwwdwimdn.er.usgs.gov

  2. Real time infrared aerosol analyzer

    DOEpatents

    Johnson, Stanley A.; Reedy, Gerald T.; Kumar, Romesh

    1990-01-01

    Apparatus for analyzing aerosols in essentially real time includes a virtual impactor which separates coarse particles from fine and ultrafine particles in an aerosol sample. The coarse and ultrafine particles are captured in PTFE filters, and the fine particles impact onto an internal light reflection element. The composition and quantity of the particles on the PTFE filter and on the internal reflection element are measured by alternately passing infrared light through the filter and the internal light reflection element, and analyzing the light through infrared spectrophotometry to identify the particles in the sample.

  3. Real-time analysis keratometer

    NASA Technical Reports Server (NTRS)

    Adachi, Iwao P. (Inventor); Adachi, Yoshifumi (Inventor); Frazer, Robert E. (Inventor)

    1987-01-01

    A computer assisted keratometer in which a fiducial line pattern reticle illuminated by CW or pulsed laser light is projected on a corneal surface through lenses, a prismoidal beamsplitter quarterwave plate, and objective optics. The reticle surface is curved as a conjugate of an ideal corneal curvature. The fiducial image reflected from the cornea undergoes a polarization shift through the quarterwave plate and beamsplitter whereby the projected and reflected beams are separated and directed orthogonally. The reflected beam fiducial pattern forms a moire pattern with a replica of the first recticle. This moire pattern contains transverse aberration due to differences in curvature between the cornea and the ideal corneal curvature. The moire pattern is analyzed in real time by computer which displays either the CW moire pattern or a pulsed mode analysis of the transverse aberration of the cornea under observation, in real time. With the eye focused on a plurality of fixation points in succession, a survey of the entire corneal topography is made and a contour map or three dimensional plot of the cornea can be made as a computer readout in addition to corneal radius and refractive power analysis.

  4. Real-time face tracking

    NASA Astrophysics Data System (ADS)

    Liang, Yufeng; Wilder, Joseph

    1998-10-01

    A real-time face tracker is presented in this paper. The system has achieved 15 frames/second tracking using a Pentium 200 PC with a Datacube MaxPCI image processing board and a Panasonic RGB color camera. It tracks human faces in the camera's field of view while people move freely. A stochastic model to characterize the skin color distribution of human skin is used to segment the face and other skin areas from the background. Median filtering is then used to clean up the background noise. Geometric constraints are applied to the segmented image to extract the face from the background. To reduce computation and achieve real-time tracking, 1D projections (horizontal and vertical) of the image are analyzed instead of the 2D image. Run-length- encoding and frequency domain analysis algorithms are used to separate faces from other skin-like blobs. The system is robust to illumination intensity variations and different skin colors. It can be applied to many human-computer interaction applications such as sound locating, lip- reading, gaze tracking and face recognition.

  5. Autonomous Real Time Requirements Tracing

    NASA Technical Reports Server (NTRS)

    Plattsmier, George; Stetson, Howard

    2014-01-01

    One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto- Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner-TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the

  6. Autonomous Real Time Requirements Tracing

    NASA Technical Reports Server (NTRS)

    Plattsmier, George I.; Stetson, Howard K.

    2014-01-01

    One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto-Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner- TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the

  7. Real-time flood forecasting

    USGS Publications Warehouse

    Lai, C.; Tsay, T.-K.; Chien, C.-H.; Wu, I.-L.

    2009-01-01

    Researchers at the Hydroinformatic Research and Development Team (HIRDT) of the National Taiwan University undertook a project to create a real time flood forecasting model, with an aim to predict the current in the Tamsui River Basin. The model was designed based on deterministic approach with mathematic modeling of complex phenomenon, and specific parameter values operated to produce a discrete result. The project also devised a rainfall-stage model that relates the rate of rainfall upland directly to the change of the state of river, and is further related to another typhoon-rainfall model. The geographic information system (GIS) data, based on precise contour model of the terrain, estimate the regions that were perilous to flooding. The HIRDT, in response to the project's progress, also devoted their application of a deterministic model to unsteady flow of thermodynamics to help predict river authorities issue timely warnings and take other emergency measures.

  8. Development of a real time monitor and multivariate method for long term diagnostics of atmospheric pressure dielectric barrier discharges: Application to He, He/N2, and He/O2 discharges

    NASA Astrophysics Data System (ADS)

    O'Connor, N.; Milosavljević, V.; Daniels, S.

    2011-08-01

    In this paper we present the development and application of a real time atmospheric pressure discharge monitoring diagnostic. The software based diagnostic is designed to extract latent electrical and optical information associated with the operation of an atmospheric pressure dielectric barrier discharge (APDBD) over long time scales. Given that little is known about long term temporal effects in such discharges, the diagnostic methodology is applied to the monitoring of an APDBD in helium and helium with both 0.1% nitrogen and 0.1% oxygen gas admixtures over periods of tens of minutes. Given the large datasets associated with the experiments, it is shown that this process is much expedited through the novel application of multivariate correlations between the electrical and optical parameters of the corresponding chemistries which, in turn, facilitates comparisons between each individual chemistry also. The results of these studies show that the electrical and optical parameters of the discharge in helium and upon the addition of gas admixtures evolve over time scales far longer than the gas residence time and have been compared to current modelling works. It is envisaged that the diagnostic together with the application of multivariate correlations will be applied to rapid system identification and prototyping in both experimental and industrial APDBD systems in the future.

  9. Changes in intraocular pressures during laparoscopy: a comparison of propofol total intravenous anesthesia to desflurane-thiopental anesthesia.

    PubMed

    Asuman, Arslan Onuk; Baris, Arslan; Bilge, Karsli; Bozkurt, Selen; Nurullah, Bülbüler; Meliha, Kahraman; Umit, Celik

    2013-02-01

    The aim of the study was to examine intraocular pressure (IOP) changes during laparoscopic cholecystectomy performed under either desflurane-thiopental anesthesia or propofol total intravenous anesthesia (TIVA). 36 patients who will undergo elective laparoscopic cholecystectomy were enrolled in the study. The patients were randomly divided into one of two groups: desflurane (Group D, n=18) or propofol (Group P, n=18). All patients received fentanyl 2 micro/kg IV, and then breathed 100% oxygen for 3 minutes prior to induction of anesthesia. Anesthesia was induced by using thiopental 5 mg/kg IV in Group D and 2 mg/kg IV propofol in group P. Neuromuscular block was achieved with rocuronium 0.6 mg/kg IV. Anesthesia was maintained with desflurane 3-6% in group D and propofol infusion 5-10 mg/kg/h in group P. Desflurane and propofol concentrations were adjusted to maintain mean arterial pressure witihin 20% of the preinduction value. During anaesthesia, fractionated doses of fentanyl 0.5-1 micro g /kg IV and maintenance doses of muscle relaxants were used. In both groups, the the mixture 60% nitrous oxide and 40% oxygen was administered used. Arterial pressure, heart rate, ETCO2, SpO2 and IOP were recorded at the predefined time points. Creation of pneumoperitoneum resulted in a significant increase in IOP which remained elevated throughout the operation in both groups. Also, we recorded a similar IOP changes with both techniques except at five minutes after pneumoperitoneum in 15 degrees reverse Trendelenburg position during desflurane-thiopental anesthesia. In c6nclusion, desflurane-thiopental anesthesia maintains the IOP at least at similar levels compared to propofol TIVA anesthesia.

  10. Effect on intraocular pressure of switching from latanoprost and travoprost monotherapy to timolol fixed combinations in patients with normal-tension glaucoma.

    PubMed

    Igarashi, Ryoko; Togano, Tetsuya; Sakaue, Yuta; Yoshino, Takaiko; Ueda, Jun; Fukuchi, Takeo

    2014-01-01

    Purpose. To evaluate the effect on intraocular pressure (IOP) of switching from latanoprost and travoprost monotherapy to timolol fixed combinations in Japanese patients with normal-tension glaucoma (NTG). Methods. 27 NTG patients (54 eyes) were compared IOP, superficial punctuate keratitis (SPK) scores, and conjunctival injection scores in eyes treated with prostaglandin (PG) or PG analog/beta-blocker (PG/b) fixed-combination 6 months after the change in therapy. Results. The mean baseline intraocular pressure was 17.4 ± 1.59 mmHg in eyes receiving PG therapy only and 17.4 ± 1.69 mmHg in eyes switched to PG/b. Switching to fixed combination therapy from PG monotherapy, the mean IOP was 13.1 ± 1.79 mmHg (P < 0.001)  (-24.71% reduction from baseline) at 6 months. The mean conjunctival injection score was 0.69 for eyes on PG monotherapy and 0.56 for eyes on fixed combination therapy (P = 0.028). The mean SPK scores were 0.46 and 0.53. This difference was not statistically significant (P = 0.463). Conclusions. Switching from PG monotherapy to PG/b fixed combination therapy for NTG resulted in a greater intraocular pressure reduction than PG alone without increasing the number of instillations.

  11. Intraocular Pressure-Lowering Potential of Subthreshold Selective Laser Trabeculoplasty in Patients with Primary Open-Angle Glaucoma

    PubMed Central

    Yang, Yang Fan; Xu, Jian Gang

    2016-01-01

    Purpose. To compare the efficacy of subthreshold and conventional selective laser trabeculoplasty (SLT) in lowering intraocular pressure (IOP) in the patients with primary open-angle glaucoma (POAG). Methods. Fifty-two eyes from fifty-two POAG patients were randomized into two groups, one group treated with subthreshold SLT using two-thirds of the conventional energy and the other one treated with the conventional energy. IOP was measured with the Goldmann tonometer and the anterior chamber inflammation was determined using laser flare meter. Results. The initial energy dosage used in subthreshold SLT group was significantly lower than the amount of the energy used in conventional SLT group (0.4 ± 0.1 mJ versus 0.6 ± 0.1 mJ, P = 0.030). The total energy dosage was also significantly lower in subthreshold SLT group compared to the other group (37.6 ± 3.3 mJ versus 51.8 ± 5.7 mJ, P = 0.036). However, the level of inflammation in aqueous humor, amount of reduction in IOP, and the success rate in controlling IOP was the same in both groups. Conclusion. The efficacy of subthreshold SLT group in reducing IOP in POAG patients is comparable to the efficacy of conventional SLT group. PMID:27529032

  12. Intraocular pressure changes following the use of silicone oil or Densiron® 68 as endotamponade in pars plana vitrectomy

    PubMed Central

    Romano, Mario R; Angi, Martina; Romano, Vito; Parmeggiani, Francesco; Campa, Claudio; Valldeperas, Xavier; Costagliola, Ciro

    2010-01-01

    Objective To compare the effects of standard silicone oil 5700 (SSO) and heavy silicone oil (HSO) such as Densiron® 68 on intraocular pressure (IOP). Materials and methods Retrospective case series including 180 eyes (105 treated with SSO and 75 with HSO). IOP was measured before surgery, 1 day after, and then at 1-, 3-, 6-, and 12-month follow-ups. Results In the SSO group, a significant increase in IOP occurred in 14% of the eyes (15/105) at 1 day postoperatively, and persisted in 11.4% (12/105) at 1-month follow-up. In the HSO group, a persistent elevated IOP was recorded in 20% of the eyes (15/75) at 1 day postoperatively, and in 16% (12/75) at 1-month follow-up. At 12-month follow-up, mean IOP was 16.7 ± 8.7 mmHg and 19.7 ± 3.8 mmHg, respectively, in the SSO and HSO groups. The difference between the 2 groups was always not significant. Conclusion Overall, the use of Densiron 68 was not associated with higher IOP values as compared with SSO. PMID:21179224

  13. A novel method to predict visual field progression more accurately, using intraocular pressure measurements in glaucoma patients

    PubMed Central

    Asaoka, Ryo; Fujino, Yuri; Murata, Hiroshi; Miki, Atsuya; Tanito, Masaki; Mizoue, Shiro; Mori, Kazuhiko; Suzuki, Katsuyoshi; Yamashita, Takehiro; Kashiwagi, Kenji; Shoji, Nobuyuki

    2016-01-01

    Visual field (VF) data were retrospectively obtained from 491 eyes in 317 patients with open angle glaucoma who had undergone ten VF tests (Humphrey Field Analyzer, 24-2, SITA standard). First, mean of total deviation values (mTD) in the tenth VF was predicted using standard linear regression of the first five VFs (VF1-5) through to using all nine preceding VFs (VF1-9). Then an ‘intraocular pressure (IOP)-integrated VF trend analysis’ was carried out by simply using time multiplied by IOP as the independent term in the linear regression model. Prediction errors (absolute prediction error or root mean squared error: RMSE) for predicting mTD and also point wise TD values of the tenth VF were obtained from both approaches. The mTD absolute prediction errors associated with the IOP-integrated VF trend analysis were significantly smaller than those from the standard trend analysis when VF1-6 through to VF1-8 were used (p < 0.05). The point wise RMSEs from the IOP-integrated trend analysis were significantly smaller than those from the standard trend analysis when VF1-5 through to VF1-9 were used (p < 0.05). This was especially the case when IOP was measured more frequently. Thus a significantly more accurate prediction of VF progression is possible using a simple trend analysis that incorporates IOP measurements. PMID:27562553

  14. A novel method to predict visual field progression more accurately, using intraocular pressure measurements in glaucoma patients.

    PubMed

    2016-01-01

    Visual field (VF) data were retrospectively obtained from 491 eyes in 317 patients with open angle glaucoma who had undergone ten VF tests (Humphrey Field Analyzer, 24-2, SITA standard). First, mean of total deviation values (mTD) in the tenth VF was predicted using standard linear regression of the first five VFs (VF1-5) through to using all nine preceding VFs (VF1-9). Then an 'intraocular pressure (IOP)-integrated VF trend analysis' was carried out by simply using time multiplied by IOP as the independent term in the linear regression model. Prediction errors (absolute prediction error or root mean squared error: RMSE) for predicting mTD and also point wise TD values of the tenth VF were obtained from both approaches. The mTD absolute prediction errors associated with the IOP-integrated VF trend analysis were significantly smaller than those from the standard trend analysis when VF1-6 through to VF1-8 were used (p < 0.05). The point wise RMSEs from the IOP-integrated trend analysis were significantly smaller than those from the standard trend analysis when VF1-5 through to VF1-9 were used (p < 0.05). This was especially the case when IOP was measured more frequently. Thus a significantly more accurate prediction of VF progression is possible using a simple trend analysis that incorporates IOP measurements. PMID:27562553

  15. Fixed combination of topical brimonidine 0.2% and timolol 0.5% for glaucoma and uncontrolled intraocular pressure

    PubMed Central

    Lee, Anne J; McCluskey, Peter

    2008-01-01

    Lowering IOP is the most readily modifiable risk factor to delay the development and progression of glaucoma (POAG). The fixed combination of brimonidine tartrate 0.2% and timolol maleate 0.5% (FCBT) combines a highly selective α2-adrenergic agonist (brimonidine) with a non-selective β-blocker (timolol). FCBT reduces aqueous production and enhances uveoscleral outflow. Concomitant brimonidine and timolol have additive effects on reducing intraocular pressure (IOP). Multi-center randomized control trials have documented superiority of FCBT twice daily on IOP control compared with monotherapy with the individual components, and equal efficacy compared with concomitant therapy. IOP reduction with FCBT versus fixed combination dorzolamide 2% and timolol 0.5% (FCDT) was similar in a small study. Other studies (n > 293) evaluating concomitant brimonidine and timolol have shown that it is not inferior to FCDT. However, concomitant brimonidine and timolol administered twice daily was significantly less efficacious in IOP reduction than fixed combination latanoprost 0.005% and timolol 0.5% (FCLT). There are no published studies comparing FCBT with FCLT. The side effect profile for FCBT reflects that of its individual components. FCBT was generally well tolerated, with less ocular side effects than brimondine alone, but more than timolol alone. Documented systemic effects were few, although this could be confounded by selection bias. FCBT is a safe and effective IOP lowering agent for POAG and ocular hypertension. PMID:19668752

  16. Intraocular Pressure, Central Corneal Thickness, and Prevalence of Open-Angle Glaucoma: The Los Angeles Latino Eye Study

    PubMed Central

    Francis, Brian A.; Varma, Rohit; Chopra, Vikas; Lai, Mei-Ying; Shtir, Corina; Azen, Stanley P.

    2008-01-01

    Purpose To examine the relationship between the prevalence of open-angle glaucoma (OAG) and intraocular pressure (IOP) and the impact of central corneal thickness (CCT) on this relationship. Design Population based cross-sectional study. Methods The study cohort consisted of 5970 participants from the Los Angeles Latino Eye Study (LALES) with no history of glaucoma treatment and with complete ophthalmic examination data. The relationship between the prevalence of OAG and IOP was contrasted across persons with CCT designated as thin, normal or thick. Results Prevalence of OAG was exponentially related to IOP. When stratified by CCT, persons with thin CCT had a significantly higher prevalence of OAG than did those with normal or thick CCT’s at all levels of IOP. Adjusting each IOP individually for CCT did not impact significantly the relationship between the prevalence of OAG and IOP. Conclusions These findings suggest that adjusting for the impact of CCT on IOP by correction algorithms is not necessary in a population analysis of glaucoma prevalence; CCT and other associated corneal properties, however, are important independent risk factors for the prevalence of OAG. PMID:18672218

  17. High intraocular pressure in four vitrectomized eyes with intravitreal C3F8 without high altitude travel

    PubMed Central

    Brosh, K; Strassman, I; Seelenfreund, M

    2014-01-01

    Importance It is well known that altitude ascent with intravitreal gas can cause expansion of gas and intraocular pressure (IOP) elevation. According to Boyle's law, the gas bubble will not expand unless a higher altitude than the gas insertion site has been reached. We report four cases in which intravitreal gas was injected at an altitude of 790 m (Jerusalem). All four cases developed high IOP even though they did not reach a higher altitude in their post-operative period. Observations A report of four patients following vitrectomy with 12% mixture of perfluoropropane and air are presented. All four patients arrived with ocular pain following the ascent by car of 765–1100 m to Jerusalem where the vitrectomy and gas insertion was conducted. Upon examination, all four patients had high IOP (30–55 mm Hg). IOP was well controlled with IOP-lowering medications. None of the patients suffered from long-term complications. Conclusions and Relevance Caution should be taken with altitude changes in patients with intravitreal gas even if there was no ascent from the altitude in which the vitrectomy was performed. PMID:24788015

  18. Modification of hydrophobic acrylic intraocular lens with poly(ethylene glycol) by atmospheric pressure glow discharge: A facile approach

    NASA Astrophysics Data System (ADS)

    Lin, Lin; Wang, Yao; Huang, Xiao-Dan; Xu, Zhi-Kang; Yao, Ke

    2010-10-01

    To improve the anterior surface biocompatibility of hydrophobic acrylic intraocular lens (IOL) in a convenient and continuous way, poly(ethylene glycol)s (PEGs) were immobilized by atmospheric pressure glow discharge (APGD) treatment using argon as the discharge gas. The hydrophilicity and chemical changes on the IOL surface were characterized by static water contact angle and X-ray photoelectron spectroscopy to confirm the covalent binding of PEG. The morphology of the IOL surface was observed under field emission scanning electron microscopy and atomic force microscopy. The surface biocompatibility was evaluated by adhesion experiments with platelets, macrophages, and lens epithelial cells (LECs) in vitro. The results revealed that the anterior surface of the PEG-grafted IOL displayed significantly and permanently improved hydrophilicity. Cell repellency was observed, especially in the PEG-modified IOL group, which resisted the attachment of platelets, macrophages and LECs. Moreover, the spread and growth of cells were suppressed, which may be attributed to the steric stabilization force and chain mobility effect of the modified PEG. All of these results indicated that hydrophobic acrylic IOLs can be hydrophilic modified by PEG through APGD treatment in a convenient and continuous manner which will provide advantages for further industrial applications.

  19. Interface Fluid Syndrome Induced by Uncontrolled Intraocular Pressure Without Triggering Factors After LASIK in a Glaucoma Patient: A Case Report.

    PubMed

    Shoji, Nobuyuki; Ishida, Akira; Haruki, Takahiro; Matsumura, Kazuhiro; Kasahara, Masayuki; Shimizu, Kimiya

    2015-09-01

    This study sought to describe a glaucoma patient with interface fluid syndrome (IFS) induced by uncontrolled intraocular pressure (IOP) without triggering factors after laser in situ keratomileusis (LASIK). Case report and review of the literature. A 23-year-old man with open-angle glaucoma underwent bilateral LASIK for myopia in 2009. Two years later, the patient reported sudden vision loss. The IOP in the right eye was not measurable using Goldmann applanation tonometry (GAT), but was determined to be 33.7 mm Hg using a noncontact tonometer. IFS was diagnosed based on the presence of space-occupying interface fluid on anterior segment optical coherence tomography images. After a trabeculectomy was performed, the IOP decreased to 10 mm Hg, and GAT measurement became possible. However, the corneal fold remained visible in the flap interface. Six months later, the IOP in the left eye increased, and a trabeculectomy was performed during the early stages of this increase in IOP. Following this procedure, the IOP decreased, and visual acuity remained stable. In glaucoma cases that involve a prior increase in IOP, IOP can continue to increase during the disease course even if temporary control of IOP has been achieved. If LASIK is performed in such cases, the treatment of glaucoma becomes insufficient because of underestimation of the typical IOP. In fact, the measurement of IOP can become difficult because of high-IOP levels. Therefore, LASIK should not be performed on patients with glaucoma who are at high risk of elevated IOP.

  20. Genome-wide analysis of multi-ancestry cohorts identifies new loci influencing intraocular pressure and susceptibility to glaucoma.

    PubMed

    Hysi, Pirro G; Cheng, Ching-Yu; Springelkamp, Henriët; Macgregor, Stuart; Bailey, Jessica N Cooke; Wojciechowski, Robert; Vitart, Veronique; Nag, Abhishek; Hewitt, Alex W; Höhn, René; Venturini, Cristina; Mirshahi, Alireza; Ramdas, Wishal D; Thorleifsson, Gudmar; Vithana, Eranga; Khor, Chiea-Chuen; Stefansson, Arni B; Liao, Jiemin; Haines, Jonathan L; Amin, Najaf; Wang, Ya Xing; Wild, Philipp S; Ozel, Ayse B; Li, Jun Z; Fleck, Brian W; Zeller, Tanja; Staffieri, Sandra E; Teo, Yik-Ying; Cuellar-Partida, Gabriel; Luo, Xiaoyan; Allingham, R Rand; Richards, Julia E; Senft, Andrea; Karssen, Lennart C; Zheng, Yingfeng; Bellenguez, Céline; Xu, Liang; Iglesias, Adriana I; Wilson, James F; Kang, Jae H; van Leeuwen, Elisabeth M; Jonsson, Vesteinn; Thorsteinsdottir, Unnur; Despriet, Dominiek D G; Ennis, Sarah; Moroi, Sayoko E; Martin, Nicholas G; Jansonius, Nomdo M; Yazar, Seyhan; Tai, E-Shyong; Amouyel, Philippe; Kirwan, James; van Koolwijk, Leonieke M E; Hauser, Michael A; Jonasson, Fridbert; Leo, Paul; Loomis, Stephanie J; Fogarty, Rhys; Rivadeneira, Fernando; Kearns, Lisa; Lackner, Karl J; de Jong, Paulus T V M; Simpson, Claire L; Pennell, Craig E; Oostra, Ben A; Uitterlinden, André G; Saw, Seang-Mei; Lotery, Andrew J; Bailey-Wilson, Joan E; Hofman, Albert; Vingerling, Johannes R; Maubaret, Cécilia; Pfeiffer, Norbert; Wolfs, Roger C W; Lemij, Hans G; Young, Terri L; Pasquale, Louis R; Delcourt, Cécile; Spector, Timothy D; Klaver, Caroline C W; Small, Kerrin S; Burdon, Kathryn P; Stefansson, Kari; Wong, Tien-Yin; Viswanathan, Ananth; Mackey, David A; Craig, Jamie E; Wiggs, Janey L; van Duijn, Cornelia M; Hammond, Christopher J; Aung, Tin

    2014-10-01

    Elevated intraocular pressure (IOP) is an important risk factor in developing glaucoma, and variability in IOP might herald glaucomatous development or progression. We report the results of a genome-wide association study meta-analysis of 18 population cohorts from the International Glaucoma Genetics Consortium (IGGC), comprising 35,296 multi-ancestry participants for IOP. We confirm genetic association of known loci for IOP and primary open-angle glaucoma (POAG) and identify four new IOP-associated loci located on chromosome 3q25.31 within the FNDC3B gene (P = 4.19 × 10(-8) for rs6445055), two on chromosome 9 (P = 2.80 × 10(-11) for rs2472493 near ABCA1 and P = 6.39 × 10(-11) for rs8176693 within ABO) and one on chromosome 11p11.2 (best P = 1.04 × 10(-11) for rs747782). Separate meta-analyses of 4 independent POAG cohorts, totaling 4,284 cases and 95,560 controls, showed that 3 of these loci for IOP were also associated with POAG.

  1. Measurement of intraocular pressure by both invasive and noninvasive techniques in rabbits exposed to head-down tilt.

    PubMed

    Setogawa, A; Kawai

    1998-02-01

    This study investigates changes in intraocular pressure (IOP) in rabbits during head-down tilt (HDT), which is commonly used as an experimental model to simulate microgravity. IOP was measured by the needle insertion technique (IOPNEEDLE) and Tono-pen tonometry (IOPTONO-PEN). Although the absolute value of the IOPTONO-PEN was significantly smaller than that of the IOPNEEDLE, a significant correlation (r = 0.99) was observed between them. A linear regression analysis yielded an equation as follows: IOPTONO-PEN = 0. 67 IOPNEEDLE - 0.67. Both the IOPNEEDLE and the IOPTONO-PEN changed depending on the tilt angle. Tilting from horizontal (0 degrees) to 75 degrees head-down increased the IOPNEEDLE and the IOPTONO-PEN by 7.3 +/- 0.8 (mean +/- SEM) mmHg and 4.4 +/- 1.3 mmHg. The IOPNEEDLE elevated from 13.1 +/- 1.3 to 16.9 +/- 1.0 mmHg immediately after the onset of 45 degrees HDT and then gradually declined. The value of the IOPNEEDLE during 8 h of HDT was significantly higher than the value in the control animals, which were kept at the horizontal prone position throughout the experiment. Similar findings were observed in the IOPTONO-PEN. These results suggest that the needle insertion technique and the Tono-pen tonometry are both useful for measuring IOP in rabbits.

  2. Genome-wide analysis of multiethnic cohorts identifies new loci influencing intraocular pressure and susceptibility to glaucoma

    PubMed Central

    Vitart, Veronique; Nag, Abhishek; Hewitt, Alex W; Höhn, René; Venturini, Cristina; Mirshahi, Alireza; Ramdas, Wishal D.; Thorleifsson, Gudmar; Vithana, Eranga; Khor, Chiea-Chuen; Stefansson, Arni B; Liao, Jiemin; Haines, Jonathan L; Amin, Najaf; Wang, Ya Xing; Wild, Philipp S; Ozel, Ayse B; Li, Jun Z; Fleck, Brian W; Zeller, Tanja; Staffieri, Sandra E; Teo, Yik-Ying; Cuellar-Partida, Gabriel; Luo, Xiaoyan; Allingham, R Rand; Richards, Julia E; Senft, Andrea; Karssen, Lennart C; Zheng, Yingfeng; Bellenguez, Céline; Xu, Liang; Iglesias, Adriana I; Wilson, James F; Kang, Jae H; van Leeuwen, Elisabeth M; Jonsson, Vesteinn; Thorsteinsdottir, Unnur; Despriet, Dominiek D.G.; Ennis, Sarah; Moroi, Sayoko E; Martin, Nicholas G; Jansonius, Nomdo M; Yazar, Seyhan; Tai, E-Shyong; Amouyel, Philippe; Kirwan, James; van Koolwijk, Leonieke M.E.; Hauser, Michael A; Jonasson, Fridbert; Leo, Paul; Loomis, Stephanie J; Fogarty, Rhys; Rivadeneira, Fernando; Kearns, Lisa; Lackner, Karl J; de Jong, Paulus T.V.M.; Simpson, Claire L; Pennell, Craig E; Oostra, Ben A; Uitterlinden, André G; Saw, Seang-Mei; Lotery, Andrew J; Bailey-Wilson, Joan E; Hofman, Albert; Vingerling, Johannes R; Maubaret, Cécilia; Pfeiffer, Norbert; Wolfs, Roger C.W.; Lemij, Hans G; Young, Terri L; Pasquale, Louis R; Delcourt, Cécile; Spector, Timothy D; Klaver, Caroline C.W.; Small, Kerrin S; Burdon, Kathryn P; Stefansson, Kari; Wong, Tien-Yin; Viswanathan, Ananth; Mackey, David A; Craig, Jamie E; Wiggs, Janey L; van Duijn, Cornelia M; Hammond, Christopher J; Aung, Tin

    2014-01-01

    Elevated intraocular pressure (IOP) is an important risk factor in developing glaucoma and IOP variability may herald glaucomatous development or progression. We report the results of a genome-wide association study meta-analysis of 18 population cohorts from the International Glaucoma Genetics Consortium (IGGC), comprising 35,296 multiethnic participants for IOP. We confirm genetic association of known loci for IOP and primary open angle glaucoma (POAG) and identify four new IOP loci located on chromosome 3q25.31 within the FNDC3B gene (p=4.19×10−08 for rs6445055), two on chromosome 9 (p=2.80×10−11 for rs2472493 near ABCA1 and p=6.39×10−11 for rs8176693 within ABO) and one on chromosome 11p11.2 (best p=1.04×10−11 for rs747782). Separate meta-analyses of four independent POAG cohorts, totaling 4,284 cases and 95,560 controls, show that three of these IOP loci are also associated with POAG. PMID:25173106

  3. Factors Influencing Intraocular Pressure Changes after Laser In Situ Keratomileusis with Flaps Created by Femtosecond Laser or Mechanical Microkeratome

    PubMed Central

    Lin, Meng-Yin; Chang, David C. K.; Shen, Yun-Dun; Lin, Yen-Kuang; Lin, Chang-Ping; Wang, I-Jong

    2016-01-01

    The aim of this study is to describe factors that influence the measured intraocular pressure (IOP) change and to develop a predictive model after myopic laser in situ keratomileusis (LASIK) with a femtosecond (FS) laser or a microkeratome (MK). We retrospectively reviewed preoperative, intraoperative, and 12-month postoperative medical records in 2485 eyes of 1309 patients who underwent LASIK with an FS laser or an MK for myopia and myopic astigmatism. Data were extracted, such as preoperative age, sex, IOP, manifest spherical equivalent (MSE), central corneal keratometry (CCK), central corneal thickness (CCT), and intended flap thickness and postoperative IOP (postIOP) at 1, 6 and 12 months. Linear mixed model (LMM) and multivariate linear regression (MLR) method were used for data analysis. In both models, the preoperative CCT and ablation depth had significant effects on predicting IOP changes in the FS and MK groups. The intended flap thickness was a significant predictor only in the FS laser group (P < .0001 in both models). In the FS group, LMM and MLR could respectively explain 47.00% and 18.91% of the variation of postoperative IOP underestimation (R2 = 0.47 and R2 = 0.1891). In the MK group, LMM and MLR could explain 37.79% and 19.13% of the variation of IOP underestimation (R2 = 0.3779 and 0.1913 respectively). The best-fit model for prediction of IOP changes was the LMM in LASIK with an FS laser. PMID:26824754

  4. Intraocular Pressure-Lowering Potential of Subthreshold Selective Laser Trabeculoplasty in Patients with Primary Open-Angle Glaucoma.

    PubMed

    Zhang, Hong Yang; Qin, Yong Jie; Yang, Yang Fan; Xu, Jian Gang; Yu, Min Bin

    2016-01-01

    Purpose. To compare the efficacy of subthreshold and conventional selective laser trabeculoplasty (SLT) in lowering intraocular pressure (IOP) in the patients with primary open-angle glaucoma (POAG). Methods. Fifty-two eyes from fifty-two POAG patients were randomized into two groups, one group treated with subthreshold SLT using two-thirds of the conventional energy and the other one treated with the conventional energy. IOP was measured with the Goldmann tonometer and the anterior chamber inflammation was determined using laser flare meter. Results. The initial energy dosage used in subthreshold SLT group was significantly lower than the amount of the energy used in conventional SLT group (0.4 ± 0.1 mJ versus 0.6 ± 0.1 mJ, P = 0.030). The total energy dosage was also significantly lower in subthreshold SLT group compared to the other group (37.6 ± 3.3 mJ versus 51.8 ± 5.7 mJ, P = 0.036). However, the level of inflammation in aqueous humor, amount of reduction in IOP, and the success rate in controlling IOP was the same in both groups. Conclusion. The efficacy of subthreshold SLT group in reducing IOP in POAG patients is comparable to the efficacy of conventional SLT group. PMID:27529032

  5. Cerebral Autoregulation Real-Time Monitoring

    PubMed Central

    Tsalach, Adi; Ratner, Eliahu; Lokshin, Stas; Silman, Zmira; Breskin, Ilan; Budin, Nahum; Kamar, Moshe

    2016-01-01

    Cerebral autoregulation is a mechanism which maintains constant cerebral blood flow (CBF) despite changes in mean arterial pressure (MAP). Assessing whether this mechanism is intact or impaired and determining its boundaries is important in many clinical settings, where primary or secondary injuries to the brain may occur. Herein we describe the development of a new ultrasound tagged near infra red light monitor which tracks CBF trends, in parallel, it continuously measures blood pressure and correlates them to produce a real time autoregulation index. Its performance is validated in both in-vitro experiment and a pre-clinical case study. Results suggest that using such a tool, autoregulation boundaries as well as its impairment or functioning can be identified and assessed. It may therefore assist in individualized MAP management to ensure adequate organ perfusion and reduce the risk of postoperative complications, and might play an important role in patient care. PMID:27571474

  6. Effect of prophylactic timolol 0.1% gel on intraocular pressure after an intravitreal injection of ranibizumab: a randomized study

    PubMed Central

    Pece, Alfredo; Allegrini, Davide; Montesano, Giovanni; Dimastrogiovanni, Andrea Fabio

    2016-01-01

    Purpose The purpose of this study is to make a prospective evaluation of the effect of timolol 0.1% eye gel on short-term intraocular pressure (IOP) after an intravitreal injection (IVI) of ranibizumab. Participants and methods One hundred and fifty eyes of 150 IVI-naïve patients with macular edema caused by various pathological conditions (age-related macular degeneration, central or branch retinal vein occlusion, and diabetic retinopathy) were scheduled to undergo an IVI of ranibizumab (0.5 mg/0.05 cc). The patients were randomly divided into three groups: 50 were not treated with timolol before the IVI (group 1); 50 received an instillation of timolol 0.1% eye gel the evening before the IVI (group 2); and 50 received an instillation of timolol 0.1% eye gel 2 hours before the IVI (group 3). The incidence of clinically significant intraocular hypertensive spikes (>25 mmHg and >40 mmHg) was then assessed. Results Our findings showed that mean IOP at baseline was significantly higher than at both 5 and 60 minutes after IVI (P<0.01). Spikes of >25 mmHg were recorded at either time in 27 patients (54%) in group 1, 23 patients (44%) in group 2, and 24 patients (48%) in group 3. None of the between-group differences were significant. Spikes of >40 mmHg (which were only detected 5 minutes after IVI) were recorded in nine (18%), eight (16%), and one patient (2%) in groups 1, 2, and 3, respectively. The only significant difference was between the control and group 3 (P=0.012). Conclusion An increase in IOP after antivascular endothelial growth factor IVI is a frequent complication. The prophylactic use of timolol 0.1% gel effectively reduced the mean IOP when administered 2 hours before IVI and was also effective in preventing dangerous IOP spikes of >40 mmHg. It is therefore recommended before IVIs as a means of preventing emergency procedures and preserving the health of the optic nerve. PMID:27382246

  7. Real-time scene generator

    NASA Astrophysics Data System (ADS)

    Lord, Eric; Shand, David J.; Cantle, Allan J.

    1996-05-01

    This paper describes the techniques which have been developed for an infra-red (IR) target, countermeasure and background image generation system working in real time for HWIL and Trial Proving applications. Operation is in the 3 to 5 and 8 to 14 micron bands. The system may be used to drive a scene projector (otherwise known as a thermal picture synthesizer) or for direct injection into equipment under test. The provision of realistic IR target and countermeasure trajectories and signatures, within representative backgrounds, enables the full performance envelope of a missile system to be evaluated. It also enables an operational weapon system to be proven in a trials environment without compromising safety. The most significant technique developed has been that of line by line synthesis. This minimizes the processing delays to the equivalent of 1.5 frames from input of target and sightline positions to the completion of an output image scan. Using this technique a scene generator has been produced for full closed loop HWIL performance analysis for the development of an air to air missile system. Performance of the synthesis system is as follows: 256 * 256 pixels per frame; 350 target polygons per frame; 100 Hz frame rate; and Gouraud shading, simple reflections, variable geometry targets and atmospheric scaling. A system using a similar technique has also bee used for direct insertion into the video path of a ground to air weapon system in live firing trials. This has provided realistic targets without degrading the closed loop performance. Delay of the modified video signal has been kept to less than 5 lines. The technique has been developed using a combination of 4 high speed Intel i860 RISC processors in parallel with the 4000 series XILINX field programmable gate arrays (FPGA). Start and end conditions for each line of target pixels are prepared and ordered in the I860. The merging with background pixels and output shading and scaling is then carried out in

  8. An ocular compression device for reduction of elevated post anesthetic intraocular pressure.

    PubMed

    S P, Preejith; Sivaprakasam, Mohanasankar; Venkatakrishnan, Jaichandran

    2014-01-01

    Rise in Intra Ocular Pressure (IOP), after administration of regional ophthalmic anesthesia for surgery, is a commonly observed clinical phenomenon. Rise in IOP increases risk of retinal ischemia and leads to surgical complications. The current clinical practice for reduction of IOP, after delivery of local anesthesia, is manually administered digital compression. The highly subjective nature of manual compression, results in unknown duration and magnitude of the pressure applied, thus limiting the clinical effectiveness of the procedure. The work presented here addresses the need for a device that delivers all the benefits of digital compression, while eliminating the uncertainty and risks involved. Design, development and clinical validation of an air pressure based compression device have been presented in this paper. This device makes the compression procedure safe and reliable by quantifying all compression parameters applied and considering safety limits for individual subjects. PMID:25571070

  9. Metal chelator combined with permeability enhancer ameliorates oxidative stress-associated neurodegeneration in rat eyes with elevated intraocular pressure.

    PubMed

    Liu, P; Zhang, M; Shoeb, M; Hogan, D; Tang, Luosheng; Syed, M F; Wang, C Z; Campbell, G A; Ansari, N H

    2014-04-01

    Because as many as half of glaucoma patients on intraocular pressure (IOP)-lowering therapy continue to experience optic nerve toxicity, it is imperative to find other effective therapies. Iron and calcium ions play key roles in oxidative stress, a hallmark of glaucoma. Therefore, we tested metal chelation by means of ethylenediaminetetraacetic acid (EDTA) combined with the permeability enhancer methylsulfonylmethane (MSM) applied topically on the eye to determine if this noninvasive treatment is neuroprotective in rat optic nerve and retinal ganglion cells exposed to oxidative stress induced by elevated IOP. Hyaluronic acid (HA) was injected into the anterior chamber of the rat eye to elevate the IOP. EDTA-MSM was applied topically to the eye for 3 months. Eyeballs and optic nerves were processed for histological assessment of cytoarchitecture. Protein-lipid aldehyde adducts and cyclooxygenase-2 (COX-2) were detected immunohistochemically. HA administration increased IOP and associated oxidative stress and inflammation. Elevated IOP was not affected by EDTA-MSM treatment. However, oxidative damage and inflammation were ameliorated as reflected by a decrease in formation of protein-lipid aldehyde adducts and COX-2 expression, respectively. Furthermore, EDTA-MSM treatment increased retinal ganglion cell survival and decreased demyelination of optic nerve compared with untreated eyes. Chelation treatment with EDTA-MSM ameliorates sequelae of IOP-induced toxicity without affecting IOP. Because most current therapies aim at reducing IOP and damage occurs even in the absence of elevated IOP, EDTA-MSM has the potential to work in conjunction with pressure-reducing therapies to alleviate damage to the optic nerve and retinal ganglion cells. PMID:24509160

  10. Real time cardiac radionuclide imaging

    SciTech Connect

    Jarkewicz, G.G.

    1986-04-29

    A data acquisition system is described for use in radionuclide cardiac imaging of a patient having been administered a myocardium specific radionuclide, comprising: (a) means for monitoring the electrical activity of the heart; (b) first temporary storage means for accumulating respective pages of data corresponding to nuclear events during each cardiac cycle; (c) means, responsive to the means for monitoring, for determining the time duration of each successive cardiac cycle; (d) means for comparing each determined duration of a cardiac cycle with a preselected time duration range; (e) second temporary storage means; and (f) means for conditionally transferring pages of data from the first temporary storage means to the second temporary storage means if the measured duration associated with each page has predetermined correspondence with the preselected duration range, whereby pages of data having the predetermined correspondence may be collated into a quasi-real time study, while pages of data having different correspondence with the preselected time duration range are discarded from the study.

  11. Mobile real time radiography system

    SciTech Connect

    Vigil, J.; Taggart, D.; Betts, S.

    1997-11-01

    A 450-keV Mobile Real Time Radiography (RTR) System was delivered to Los Alamos National Laboratory (LANL) in January 1996. It was purchased to inspect containers of radioactive waste produced at (LANL). Since its delivery it has been used to radiograph more than 600 drums of radioactive waste at various LANL sites. It has the capability of inspecting waste containers of various sizes from <1-gal. buckets up to standard waste boxes (SWB, dimensions 54.5 in. x 71 in. x 37 in.). It has three independent x-ray acquisition formats. The primary system used is a 12- in. image intensifier, the second is a 36-in. linear diode array (LDA) and the last is an open system. It is fully self contained with on board generator, HVAC, and a fire suppression system. It is on a 53-ft long x 8-ft. wide x 14-ft. high trailer that can be moved over any highway requiring only an easily obtainable overweight permit because it weights {approximately}38 tons. It was built to conform to industry standards for a cabinet system which does not require an exclusion zone. The fact that this unit is mobile has allowed us to operate where the waste is stored, rather than having to move the waste to a fixed facility.

  12. Potentials of real time control, stormwater infiltration and urine separation to minimize river impacts: dynamic long term simulation of sewer network, pumping stations, pressure pipes and waste water treatment plant.

    PubMed

    Peters, C; Keller, S; Sieker, H; Jekel, M

    2007-01-01

    River Panke (Berlin, Germany) suffers from hydraulic peak loads and pollutant loads from separate sewers and combined sewer overflows (CSOs). Pumping the wastewater through long pressure pipes causes extreme peak loads to the wastewater treatment plant (WWTP) during stormwater events. In order to find a good solution, it is essential not to decide on one approach at the beginning, but to evaluate a number of different approaches. For this reason, an integrated simulation study is carried out, assessing the potentials of real time control (RTC), stormwater infiltration, storage and urine separation. Criteria for the assessment are derived and multi-criteria analysis is applied. Despite spatial limitations, infiltration has the highest potential and is very effective with respect to both overflows and the WWTP. Due to a high percentage of separate systems, urine separation has a similar potential and causes the strongest benefits at the WWTP. Unconventional control strategies can lead to significant improvement (comparable to infiltrating the water from approximately 10% of the sealed area).

  13. Students Collecting Real time Data

    NASA Astrophysics Data System (ADS)

    Miller, P.

    2006-05-01

    Students Collecting Real-Time Data The Hawaiian Islands Humpback Whale National Marine Sanctuary has created opportunities for middle and high school students to become Student Researchers and to be involved in real-time marine data collection. It is important that we expose students to different fields of science and encourage them to enter scientific fields of study. The Humpback Whale Sanctuary has an education visitor center in Kihei, Maui. Located right on the beach, the site has become a living classroom facility. There is a traditional Hawaiian fishpond fronting the property. The fishpond wall is being restored, using traditional methods. The site has the incredible opportunity of incorporating Hawaiian cultural practices with scientific studies. The Sanctuary offers opportunities for students to get involved in monitoring and data collection studies. Invasive Seaweed Study: Students are collecting data on invasive seaweed for the University of Hawaii. They pull a large net through the shallow waters. Seaweed is sorted, identified and weighed. The invasive seaweeds are removed. The data is recorded and sent to UH. Remote controlled monitoring boats: The sanctuary has 6 boogie board sized remote controlled boats used to monitor reefs. Boats have a camera with lights on the underside. The boats have water quality monitoring devices and GPS units. The video from the underwater camera is transmitted via a wireless transmission. Students are able to monitor the fish, limu and invertebrate populations on the reef and collect water quality data via television monitors or computers. The boat can also pull a small plankton tow net. Data is being compiled into data bases. Artificial Reef Modules: The Sanctuary has a scientific permit from the state to build and deploy artificial reef modules. High school students are designing and building modules. These are deployed out in the Fishpond fronting the Sanctuary site and students are monitoring them on a weekly basis

  14. Real-Time Data Display

    NASA Technical Reports Server (NTRS)

    Pedings, Marc

    2007-01-01

    RT-Display is a MATLAB-based data acquisition environment designed to use a variety of commercial off-the-shelf (COTS) hardware to digitize analog signals to a standard data format usable by other post-acquisition data analysis tools. This software presents the acquired data in real time using a variety of signal-processing algorithms. The acquired data is stored in a standard Operator Interactive Signal Processing Software (OISPS) data-formatted file. RT-Display is primarily configured to use the Agilent VXI (or equivalent) data acquisition boards used in such systems as MIDDAS (Multi-channel Integrated Dynamic Data Acquisition System). The software is generalized and deployable in almost any testing environment, without limitations or proprietary configuration for a specific test program or project. With the Agilent hardware configured and in place, users can start the program and, in one step, immediately begin digitizing multiple channels of data. Once the acquisition is completed, data is converted into a common binary format that also can be translated to specific formats used by external analysis software, such as OISPS and PC-Signal (product of AI Signal Research Inc.). RT-Display at the time of this reporting was certified on Agilent hardware capable of acquisition up to 196,608 samples per second. Data signals are presented to the user on-screen simultaneously for 16 channels. Each channel can be viewed individually, with a maximum capability of 160 signal channels (depending on hardware configuration). Current signal presentations include: time data, fast Fourier transforms (FFT), and power spectral density plots (PSD). Additional processing algorithms can be easily incorporated into this environment.

  15. Intraocular pressure effects of water loading and venous compression tests in normal and denervated pigmented rabbits.

    PubMed

    Gual, A; Mintenig, G M; Belmonte, C

    1989-03-01

    We have compared IOP elevations induced by water-loading and by increased cephalic venous pressure in normal and denervated pigmented rabbits. Denervations were performed by sympathetic ganglionectomy and/or blockade of the sensory and autonomic innervation of the eye through retrobulbar anesthesia; retrobulbar anesthesia induced significant decreases of the basal IOP in control but not in ganglionectomized eyes. The water-loading test induced a peak pressure elevation approximately 30 min after water administration that could be counteracted by retrobulbar anesthesia. Ganglionectomized rabbits exhibited steeper IOP rises and greater IOP increases following water-loading than the control eyes; retrobulbar anesthesia in ganglionectomized eyes delayed the IOP response to water-loading. Compressions of the neck lasting 30 min elicited significant IOP elevations that were more pronounced in ganglionectomized eyes. In these eyes, retrobulbar anesthesia further increased the IOP rise elicited by neck compression. An IOP decrease below control values was observed at the end of the venous compression. The results indicate that an intact efferent innervation of the eye contributes to buffer IOP elevations induced by water-loading or cephalic venous stasis, presumably through the vascular effects of the ocular autonomic nerves.

  16. The Relationship between Corvis ST Tonometry Measured Corneal Parameters and Intraocular Pressure, Corneal Thickness and Corneal Curvature

    PubMed Central

    Asaoka, Ryo; Nakakura, Shunsuke; Tabuchi, Hitoshi; Murata, Hiroshi; Nakao, Yoshitaka; Ihara, Noriko; Rimayanti, Ulfah; Aihara, Makoto; Kiuchi, Yoshiaki

    2015-01-01

    The purpose of the study was to investigate the correlation between Corneal Visualization Scheimpflug Technology (Corvis ST tonometry: CST) parameters and various other ocular parameters, including intraocular pressure (IOP) with Goldmann applanation tonometry. IOP with Goldmann applanation tonometry (IOP-G), central corneal thickness (CCT), axial length (AL), corneal curvature, and CST parameters were measured in 94 eyes of 94 normal subjects. The relationship between ten CST parameters against age, gender, IOP-G, AL, CST-determined CCT and average corneal curvature was investigated using linear modeling. In addition, the relationship between IOP-G versus CST-determined CCT, AL, and other CST parameters was also investigated using linear modeling. Linear modeling showed that the CST measurement ‘A time-1’ is dependent on IOP-G, age, AL, and average corneal curvature; ‘A length-1’ depends on age and average corneal curvature; ‘A velocity-1’ depends on IOP-G and AL; ‘A time-2’ depends on IOP-G, age, and AL; ‘A length-2’ depends on CCT; ‘A velocity-2’ depends on IOP-G, age, AL, CCT, and average corneal curvature; ‘peak distance’ depends on gender; ‘maximum deformation amplitude’ depends on IOP-G, age, and AL. In the optimal model for IOP-G, A time-1, A velocity-1, and highest concavity curvature, but not CCT, were selected as the most important explanatory variables. In conclusion, many CST parameters were not significantly related to CCT, but IOP usually was a significant predictor, suggesting that an adjustment should be made to improve their usefulness for clinical investigations. It was also suggested CST parameters were more influential for IOP-G than CCT and average corneal curvature. PMID:26485129

  17. Comparison study of intraocular pressure reduction efficacy and safety between latanoprost and tafluprost in Japanese with normal-tension glaucoma

    PubMed Central

    Ikeda, Yoko; Mori, Kazuhiko; Tada, Kaori; Ueno, Morio; Kinoshita, Shigeru; Sotozono, Chie

    2016-01-01

    Purpose To evaluate and compare the intraocular pressure (IOP) reduction efficacy and safety between the ophthalmic solutions 0.005% latanoprost (Lat) and 0.0015% tafluprost (Taf) in Japanese patients with normal-tension glaucoma (NTG). Methods In this randomized nonmasked study, we prospectively enrolled 30 Japanese NTG patients who had used Lat monotherapy for more than 4 weeks, and randomly divided them into the following two groups: 1) Lat-to-Taf group (LT group) and 2) Taf-to-Lat group (TL group). At the beginning of the study, both groups were switched from initial Lat to Lat or Taf for 12 weeks, and then switched over to the other drug (crossover) for 12 additional weeks. At 0, 4, 12, 16, and 24 weeks, we evaluated each patient’s IOP, conjunctival injection, and corneal epitheliopathy score, and at 0, 12, and 24 weeks, we evaluated their eyelash changes and pigmentation of the eyelids and irises. Results The mean IOP of the LT group (15 eyes) was 10.5, 10.6, and 11.1 mmHg, at 0, 12, and 24 weeks, respectively, whereas that of the TL group (15 eyes) was 11.7, 11.1, and 10.5 mmHg at 0, 12, and 24 weeks, respectively. No significant differences were found between the two groups and in the intragroup comparisons. Moreover, no significant differences were found between Lat and Taf in regard to the conjunctival injection score and corneal epitheliopathy score. Eyelash changes and eyelid and iris pigmentation were similar in both groups. Conclusion The findings of this study show that Lat and Taf have equivalent efficacy and safety in Japanese patients with NTG. PMID:27601879

  18. The Effect of Diurnal Fluctuation in Intraocular Pressure on the Evaluation of Risk Factors of Progression in Normal Tension Glaucoma

    PubMed Central

    Kim, Seung Hoon; Lee, Eun Jung; Han, Jong Chul; Sohn, Sae Woon; Rhee, Taekkwan; Kee, Changwon

    2016-01-01

    Purpose To investigate whether diurnal fluctuation in intraocular pressure (IOP) can influence the result of the correlations between IOP-related factors and progression of normal tension glaucoma (NTG). Methods Glaucoma progression was defined as visual field (VF) progression and changes in the optic disc and/or retinal nerve fiber layer (RNFL). Two different methods were used to evaluate the impact of the diurnal fluctuation in IOP. ‘Conventional method’ used in previous studies included all IOP measurements during the follow up time. ‘Time adjusted method’ was used to adjust diurnal fluctuation in IOP with the preferred time. Mean IOP, long term IOP fluctuation and the difference between the lowest and highest IOP were calculated using both methods. Cox regression analyses were performed to evaluate the association between IOP-related factors and NTG progression. Results One hundred and forty eyes of 140 patients with NTG were included in this study. 41% (58 of 140 eyes) of eyes underwent NTG progression. Long term IOP variation calculated by conventional method was not a significant risk factor for NTG progression (hazard ratio[HR], 0.311; 95% confidence interval[CI], 0.056–1.717; P = 0.180). Long term IOP variation calculated by time adjusted method, however, was related to progression, with an HR of 5.260 (95% CI,1.191–23.232; P = 0.029). Conclusion Although having the same IOP-related factors, if diurnal fluctuation is included, different results may be found on the relationship between IOP-related factors and NTG progression. Based on our results, diurnal fluctuation in IOP should be considered when IOP-related factors are studied in the future. PMID:27776182

  19. Repeatability, reproducibility and agreement of intraocular pressure measurement in rabbits by the TonoVet and Tono-Pen

    PubMed Central

    Ma, Di; Chen, Chong-Bo; Liang, Jiajian; Lu, Zhihao; Chen, Haoyu; Zhang, Mingzhi

    2016-01-01

    Tono-Pen and TonoVet have been used in rabbits to measure intraocular pressure (IOP) and investigate the effect of IOP lowering therapies. Therefore, their reliability and accuracy are very important and deserve careful evaluation. Our results showed that the with-subject deviation (Sw) and intraclass correlation coefficient (ICC) of the TonoVet and Tono-Pen were 0.61 mmHg/0.83 mmHg and 0.97/0.94, respectively for intrasession repeatability. For intersession reproducibility, the Sw and ICC of TonoVet and Tono-Pen were 1.42 mmHg/1.66 mmHg and 0.73/0.67, respectively. For interoperator reproducibility, the Sw and ICC of the TonoVet and Tono-Pen were 0.72 mmHg/1.11 mmHg and 0.91/0.82 respectively. Both TonoVet and Tono-Pen underestimated the IOP measured by manometry. The regression function was: y = 0.8249x + 0.1011 and y =0.6881x + 2.2290 for TonoVet and Tono-Pen, respectively. Our study suggests that both TonoVet and Tono-Pen had excellent intrasession repeatability and inter-operator reproducibility, but good intersession reproducibility. Both TonoVet and Tono-Pen correlated well with manometry, but underestimated the manometric IOP with presence of fixed and proportional biases. These factors should be considered when measuring IOP with Tono-Pen or TonoVet in rabbit eyes. PMID:27731381

  20. Association of biometric factors with anterior chamber angle widening and intraocular pressure reduction after uneventful phacoemulsification for cataract

    PubMed Central

    Huang, Guofu; Gonzalez, Eduardo; Lee, Roland; Chen, Yi-Chun; He, Mingguang; Lin, Shan C.

    2011-01-01

    PURPOSE To evaluate anterior chamber biometric factors associated with the degree of angle widening and intraocular pressure (IOP) reduction after phacoemulsification. SETTING University of California, San Francisco, California, USA. DESIGN Case series. METHODS Anterior chamber parameters obtained by anterior segment coherence tomography were compared preoperatively and 3 months postoperatively. Measurements included the angle opening distance 500 μm anterior to the scleral spur (AOD500), trabecular–iris space area 500 μm from the scleral spur (TISA500), iris curvature (I-Curv), anterior chamber angle (ACA), trabecular–iris space area, anterior chamber volume, anterior chamber width, and lens vault (LV). RESULTS The study enrolled 73 eyes. The mean patient age was 77.45 years ± 7.84 (SD); 65.75% of patients were women. From preoperatively to 3 months postoperatively, the mean AOD500 increased significantly (0.254 ± 0.105 to 0.433 ± 0.108 mm) and the mean IOP decreased significantly (14.97 ± 3.35 to 12.62 ± 3.37 mm Hg) (P < .001). The reduction in IOP was correlated with the increase in AOD500 (r = 0.240, P = .041) and preoperative LV (r = 0.235, P = .045). After adjusting for related factors, AOD500 widening was positively correlated with LV (β = 0.458, P = .044) and I-Curv (β = 0.235, P = .043) and negatively correlated with preoperative TISA500 (β = −0.269, P = .025) and ACA (β = −0.919, P = .027). CONCLUSIONS Surgically induced AOD widening was significantly correlated with anterior chamber biometric factors. Preoperative LV appears to be a significant factor in angle widening and IOP reduction after phacoemulsification. PMID:22055073

  1. Clinical utility and differential effects of prostaglandin analogs in the management of raised intraocular pressure and ocular hypertension

    PubMed Central

    Lee, Anne J; McCluskey, Peter

    2010-01-01

    Prostaglandin analogs (PGA) are powerful topical ocular hypotensive agents available for the treatment of elevated intraocular pressure (IOP). Latanoprost 0.005% and travoprost 0.004% are prodrugs and analogs of prostaglandin F2α. Bimatoprost 0.03% is regarded as a prostamide, and debate continues as to whether it is a prodrug. The free acids of all 3 PGAs reduce IOP by enhancing uveoscleral and trabecular outflow via direct effects on ciliary muscle relaxation and remodeling of extracellular matrix. The vast majority of clinical trials demonstrate IOP-lowering superiority of latanoprost, bimatoprost and travoprost compared with timolol 0.5%, brimonidine 0.2%, or dorzolamide 2% monotherapy. Bimatoprost appears to be more efficacious in IOP-lowering compared with latanoprost, with weighted mean difference in IOP reduction documented in one meta-analysis of 2.59% to 5.60% from 1- to 6-months study duration. PGAs reduce IOP further when used as adjunctive therapy. Fixed combinations of latanoprost, bimatoprost or travoprost formulated with timolol 0.5% and administered once daily are superior to monotherapy of its constituent parts. PGA have near absence of systemic side effects, although do have other commonly encountered ocular adverse effects. The adverse effects of PGA, and also those found more frequently with bimatoprost use include ocular hyperemia, eyelash growth, and peri-ocular pigmentary changes. Iris pigmentary change is unique to PGA treatment. Once daily administration and near absence of systemic side effects enhances tolerance and compliance. PGAs are often prescribed as first-line treatment for ocular hypertension and open-angle glaucoma. PMID:20689791

  2. Lens Position Parameters as Predictors of Intraocular Pressure Reduction After Cataract Surgery in Nonglaucomatous Patients With Open Angles

    PubMed Central

    Hsu, Chi-Hsin; Kakigi, Caitlin L.; Lin, Shuai-Chun; Wang, Yuan-Hung; Porco, Travis; Lin, Shan C.

    2015-01-01

    Purpose To evaluate the relationship between lens position parameters and intraocular pressure (IOP) reduction after cataract surgery in nonglaucomatous eyes with open angles. Methods The main outcome of the prospective study was percentage of IOP change, which was calculated using the preoperative IOP and the IOP 4 months after cataract surgery in nonglaucomatous eyes with open angles. Lens position (LP), defined as anterior chamber depth (ACD) + 1/2 lens thickness (LT), was assessed preoperatively using parameters from optical biometry. Preoperative IOP, central corneal thickness, ACD, LT, axial length (AXL), and the ratio of preoperative IOP to ACD (PD ratio) were also evaluated as potential predictors of percentage of IOP change. The predictive values of the parameters we found to be associated with the primary outcome were compared. Results Four months after cataract surgery, the average IOP reduction was 2.03 ± 2.42 mm Hg, a 12.74% reduction from the preoperative mean of 14.5 ± 3.05 mm Hg. Lens position was correlated with IOP reduction percentage after adjusting for confounders (P = 0.002). Higher preoperative IOP, shallower ACD, shorter AXL, and thicker LT were significantly associated with percentage of IOP decrease. Although not statistically significant, LP was a better predictor of percentage of IOP change compared to PD ratio, preoperative IOP, and ACD. Conclusions The percentage of IOP reduction after cataract surgery in nonglaucomatous eyes with open angles is greater in more anteriorly positioned lenses. Lens position, which is convenient to compute by basic ocular biometric data, is an accessible predictor with considerable predictive value for postoperative IOP change. PMID:26650901

  3. Prolonged elevation of intraocular pressure results in retinal ganglion cell loss and abnormal retinal function in mice

    PubMed Central

    Khan, A Kareem; Tse, Dennis Y; van der Heijden, Meike; Shah, Priya; Nusbaum, Derek; Yang, Zhuo; Wu, Samuel M; Frankfort, Benjamin J

    2014-01-01

    The purpose of this study was to assess the impact of prolonged intraocular pressure (IOP) elevation on retinal anatomy and function in a mouse model of experimental glaucoma. IOP was elevated by anterior chamber injection of a fixed combination of polystyrene beads and sodium hyaluronate, and maintained via re-injection after 24 weeks. IOP was measured weekly with a rebound tonometer for 48 weeks. Histology was assessed with a combination of retrograde labeling and antibody staining. Retinal physiology and function was assessed with dark-adapted electroretinograms (ERGs). Comparisons between bead-injected animals and various controls were conducted at both 24 and 48 weeks after bead injection. IOP was elevated throughout the study. IOP elevation resulted in a reduction of retinal ganglion cell (RGCs) and an increase in axial length at both 24 and 48 weeks after bead injection. The b-wave amplitude of the ERG was increased to the same degree in bead-injected eyes at both time points, similar to previous studies. The positive scotopic threshold response (pSTR) amplitude, a measure of RGC electrical function, was diminished at both 24 and 48 weeks when normalized to the increased b-wave amplitude. At 48 weeks, the pSTR amplitude was reduced even without normalization, suggesting more profound RGC dysfunction. We conclude that injection of polystyrene beads and sodium hyaluronate causes chronic IOP elevation which results in phenotypes of stable b-wave amplitude increase and progressive pSTR amplitude reduction, as well as RGC loss and axial length elongation. PMID:25450059

  4. Lack of Visual Field Improvement After Initiation of Intraocular Pressure Reducing Treatment in the Early Manifest Glaucoma Trial

    PubMed Central

    Bengtsson, Boel; Heijl, Anders

    2016-01-01

    Purpose We evaluate how visual fields are affected by the initiation of IOP-reducing therapy in previously untreated glaucoma individuals. Methods Qualifying individuals with newly diagnosed glaucoma having normal to moderately elevated IOP were prospectively randomized either to IOP-reducing therapy or to no treatment. Before randomization, individuals underwent repeatedly Standard Automated Perimetry (SAP) testing and Goldmann tonometry. Three months after randomization, patients again underwent SAP and tonometry. Changes between baseline and the 3-month follow-up visit in the perimetric summary index, mean deviation (MD), and total deviation values at significantly depressed test points were compared between the treated and untreated groups. Results Of 255 individuals studied, 129 were randomized to treatment and 126 to no treatment. Intraocular pressure decreased by an average of 24% among treated and by 0.6% in the untreated patients. Mean deviation deteriorated slightly in both groups; mean change was −0.15 and −0.44 dB in the treated and untreated groups, respectively; the difference was not statistically significant, (P = 0.16). No association was seen between IOP reduction and change in MD. Sensitivities decreased slightly in significantly depressed test points, mean change was −0.45 dB in the untreated and −0.38 dB in the treated groups (P = 0.88). Conclusions Observed visual field changes among glaucoma patients receiving initial IOP-reducing therapy were not significantly different to changes seen in patients who received no treatment. Thus, our results did not support the idea that visual field status improves after initiation of IOP- reducing therapy in glaucoma individuals, at least not in individuals with initially normal to moderately elevated IOPs. PMID:27768797

  5. Comparison of intraocular pressure measurement with Scheimpflug-based noncontact tonometer with and without hydrogel contact lenses

    PubMed Central

    Kumar, Mukesh; Shetty, Rohit; Jayadev, Chaitra; Dutta, Debarun; Nicolsan, Maneck D; Nagaraj, Sriharsha; Kumar, Rajesh S

    2015-01-01

    Objectives: The objective was to determine the repeatability of intraocular pressure (IOP) measurements made through a soft contact lens (CL) using the Scheimpflug noncontact tonometry in healthy subjects. Methods: This prospective, randomized, single-center study included one eye of 88 subjects (40 male and 48 female). Only participants without glaucoma or any other ocular pathology were included in this study. Three consecutive IOP measurements by the Scheimpflug noncontact tonometry were performed with and without daily disposable hydrogel CLs (−0.50 DS) (Dailies-nelfilcon A, 69% water, 8.7 mm base curve, 14 mm diameter, center thickness 0.10 mm) by a single operator. To avoid any bias arising from diurnal variation, all measurements were made at a similar time of day (11 am ± 1 h). The repeatability of IOP measurements using the Scheimpflug noncontact tonometry with and without CLs was evaluated using Pearson's correlation analysis. Bland-Altman plotting was used to assess the limits of agreement between the measurements with and without CLs. Results: The mean (± standard deviation) IOPs with and without CL were 13.80 ± 2.70 and 13.79 ± 2.54 mm of Hg respectively. The mean difference was 0.01 ± 0.16 (95% confidence interval, +1.97 to − 2.00) mm Hg. Statistical analysis via paired t-test showed no statistical difference between the two groups with (P = 0.15). A good correlation was found for IOP measurements with and without CL (r = 0.93, P < 0.001). Good test-retest reliability was found when IOP was measured with and without CL. Conclusion: There was no significant difference between IOP measured with and without CLs by Scheimpflug noncontact tonometry. PMID:26044471

  6. Iris transillumination defect and its gene modulators do not correlate with intraocular pressure in the BXD family of mice

    PubMed Central

    Lu, Hong; Lu, Lu; Williams, Robert W.

    2016-01-01

    Purpose Intraocular pressure (IOP) is currently the only treatable phenotype associated with primary open angle glaucoma (POAG). Our group has developed the BXD murine panel for identifying genetic modulators of the various endophenotypes of glaucoma, including pigment dispersion, IOP, and retinal ganglion cell (RGC) death. The BXD family consists of the inbred progeny of crosses between the C57BL/6J (B6) strain and the glaucoma-prone DBA/2J (D2) strain that has mutations in Tyrp1 and Gpnmb. The role of these genes in the iris transillumination defect (TID) has been well documented; however, their possible roles in modulating IOP during glaucoma onset and progression are yet not well understood. Methods We used the IOP data sets and the Eye M430v2 (Sep08) RMA Database available on GeneNetwork to determine whether mutations in Tyrp1 and Gpnmb or TIDs have a direct role in the elevation of IOP in the BXD family. We also determined whether TIDs and IOP are coregulated. Results As expected, Tyrp1 and Gpnmb expression levels showed a high degree of correlation with TIDs. However, there was no correlation between the expression of these genes and IOP. Moreover, unlike TIDs, IOP did not map to either the Tyrp1 or Gpnmb locus. Although the Tyrp1 and Gpnmb mutations in BXD strains are a prerequisite for the development of TID, they are not required for or associated with elevated IOP. Conclusions Genetic modulators of IOP thus may be independently identified using the full array of BXD mice without concern for the presence of TIDs or mutations in Typr1 and/or Gpnmb. PMID:27011731

  7. Comparison study of intraocular pressure reduction efficacy and safety between latanoprost and tafluprost in Japanese with normal-tension glaucoma

    PubMed Central

    Ikeda, Yoko; Mori, Kazuhiko; Tada, Kaori; Ueno, Morio; Kinoshita, Shigeru; Sotozono, Chie

    2016-01-01

    Purpose To evaluate and compare the intraocular pressure (IOP) reduction efficacy and safety between the ophthalmic solutions 0.005% latanoprost (Lat) and 0.0015% tafluprost (Taf) in Japanese patients with normal-tension glaucoma (NTG). Methods In this randomized nonmasked study, we prospectively enrolled 30 Japanese NTG patients who had used Lat monotherapy for more than 4 weeks, and randomly divided them into the following two groups: 1) Lat-to-Taf group (LT group) and 2) Taf-to-Lat group (TL group). At the beginning of the study, both groups were switched from initial Lat to Lat or Taf for 12 weeks, and then switched over to the other drug (crossover) for 12 additional weeks. At 0, 4, 12, 16, and 24 weeks, we evaluated each patient’s IOP, conjunctival injection, and corneal epitheliopathy score, and at 0, 12, and 24 weeks, we evaluated their eyelash changes and pigmentation of the eyelids and irises. Results The mean IOP of the LT group (15 eyes) was 10.5, 10.6, and 11.1 mmHg, at 0, 12, and 24 weeks, respectively, whereas that of the TL group (15 eyes) was 11.7, 11.1, and 10.5 mmHg at 0, 12, and 24 weeks, respectively. No significant differences were found between the two groups and in the intragroup comparisons. Moreover, no significant differences were found between Lat and Taf in regard to the conjunctival injection score and corneal epitheliopathy score. Eyelash changes and eyelid and iris pigmentation were similar in both groups. Conclusion The findings of this study show that Lat and Taf have equivalent efficacy and safety in Japanese patients with NTG.

  8. Feasibility study of sustained-release travoprost punctum plug for intraocular pressure reduction in an Asian population

    PubMed Central

    Perera, Shamira A; Ting, Daniel SW; Nongpiur, Monisha E; Chew, Paul T; Aquino, Maria Cecilia D; Sng, Chelvin CA; Ho, Sue-Wei; Aung, Tin

    2016-01-01

    Purpose To investigate the efficacy and safety of a punctum plug-based sustained drug release system for a prostaglandin analog, travoprost (OTX-TP), for intraocular pressure (IOP) reduction in an Asian population. Methods This is an initial feasibility, prospective, single-arm study involving 26 eyes and a bioresorbable punctum plug containing OTX-TP. An OTX-TP was placed in the vertical portion of the superior or inferior canaliculus of patients with primary open-angle glaucoma or ocular hypertension. The main outcome measure was the IOP-lowering efficacy of OTX-TP at 3 (8 am) and 10, 20, and 30 days (8 am, 10 am, and 4 pm), compared to baseline. Results A total of 26 OTX-TP were inserted for 17 subjects. The mean (standard deviation) age was 57.2 (13.8) years. At 10 days, all plugs were still present, and the IOP reduction from baseline was 6.2 (23%), 5.4 (21%), and 7.5 mmHg (28%) at 8 am, 10 am, and 4 pm, respectively. At 10 days, the mean IOP (standard error of mean) was 21.2 (1.2), 20.4 (0.8), and 19.7 (1.0) at 8 am, 10 am, and 4 pm, respectively, showing no discernible IOP trend during the course of the day. At 30 days, plug retention had declined to 42%, and the overall IOP reduction had decreased to 16%. Conclusion The sustained-release OTX-TP is able to reduce IOP by 24% (day 10) and 15.6% (day 30), respectively. It is a potentially well-tolerable ocular hypotensive for glaucoma patients with a history of poor compliance. PMID:27175058

  9. Age-Related Changes of Intraocular Pressure in Elderly People in Southern China: Lingtou Eye Cohort Study

    PubMed Central

    Han, Xiaotong; Niu, Yong; Guo, Xinxing; Hu, Yin; Yan, William; He, Mingguang

    2016-01-01

    Purpose To study age-related changes of intraocular pressure (IOP) and assess the cohort effect in both cross-sectional and longitudinal settings among elderly Chinese adults. Methods Participants were enrolled from the Lingtou Eye Cohort Study with Chinese government officials aged 40 years and older at baseline and received physical check-up and ocular examinations from 2010 to 2012. IOP was measured using a non-contact tonometer according to standardized protocols, as well as systolic blood pressure (SBP), diastolic blood pressure (DBP) and body mass index (BMI). Participants who had attended IOP measurements in both 2010 and 2012 were included in this study. Cross-sectional association of IOP with age was assessed using multivariate liner regression analyses and based on the data of 2010. Longitudinal changes in IOP were assessed by paired t-test. Results A total of 3372 subjects were enrolled in the current analysis (2010 mean [SD] age, 61.9 [7.1] years; 60.2% men). The mean IOP in 2010 was 15.4±2.3 mmHg for women and 15.2±2.3 mmHg for men with an intersex difference (P = 0.029). Cross-sectional analysis showed that IOP was negatively associated with age (P = 0.003, β = -0.033 for women and P<0.001, β = -0.061 for men) adjusted for baseline SBP, DBP and BMI. Paired t-test suggested that IOP was higher in the year 2012 than 2010 in women (P = 0.006) but did not change significantly in men within 2 years (P = 0.345). In addition, the 2-year changes of IOP were not associated with age adjusted for baseline IOP in 2010 (P = 0.249). Conclusion Cross-sectional data suggests that IOP is lower in people with older age. Longitudinal data does not support such findings and thus the identified decreasing pattern with age in cross-sectional analysis is likely caused by cohort effects. PMID:26986222

  10. Geodynamic monitoring in real times

    NASA Astrophysics Data System (ADS)

    Outkin, V.; Yurkov, A.; Klimshin, A.; Kozlova, I.

    2011-12-01

    For the decision of problems of the short-term and intermediate term forecast of tectonic earthquakes the technique conditionally named - geodynamic monitoring which does not use the data of seismic monitoring for the operative decision of problems of the forecast is offered. Geodynamic monitoring (GDM) is to studying tensely - deformed conditions of the separate block of rock on change of activity natural radioactive gas is carried out by accommodation in the chosen file of specially designed monitors of radon - devices fixing change in time (VAR). The monitor of radon, (the detector of radon) as the basic measuring device located in the block of rocks, possesses enormous tensosensitivity to relative strain condition of a file. Depending on the enclosed pressure choose three characteristic points: 1) 30-35 % of "background" size VAR - the beginning of accumulation of inelastic energy; 2) 50 % of background VAR - the process of stabilization of an elastic condition of a file; 3) 70-75 % "background" VAR - a critical pressure in the mountain block, an opportunity as spontaneous dump of elastic energy, and under action external "triggerring" forces. If the size of the saved up energy is close to critical dump needs energy at a level of energy of variations of rotation of the Earth. Such significant energy causes "plenty" of earthquakes on all planet simultaneously. This fact confirms an opportunity of the short-term forecast of strong (destructive) earthquakes: dump of elastic pressure of the Earth in this case occurs in 25-30 hours after passage of variations of rotation of the Earth. It is for the notification of the population about coming nearer earthquake. External power functions (mechanical, electromagnetic, etc.), preparations influencing system and occurrence of tectonic earthquakes, are divided on two big classes: 1) "forecasting " functions - processes functionally connected to accumulation of elastic pressure and to dump by its rather small dozes; 2

  11. Analysis of the effects of non-supine sleeping positions on the stress, strain, deformation and intraocular pressure of the human eye

    NASA Astrophysics Data System (ADS)

    Volpe, Peter A.

    This thesis presents analytical models, finite element models and experimental data to investigate the response of the human eye to loads that can be experienced when in a non-supine sleeping position. The hypothesis being investigated is that non-supine sleeping positions can lead to stress, strain and deformation of the eye as well as changes in intraocular pressure (IOP) that may exacerbate vision loss in individuals who have glaucoma. To investigate the quasi-static changes in stress and internal pressure, a Fluid-Structure Interaction simulation was performed on an axisymmetrical model of an eye. Common Aerospace Engineering methods for analyzing pressure vessels and hyperelastic structural walls are applied to developing a suitable model. The quasi-static pressure increase was used in an iterative code to analyze changes in IOP over time.

  12. Research in Distributed Real-Time Systems

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.

    1997-01-01

    This document summarizes the progress we have made on our study of issues concerning the schedulability of real-time systems. Our study has produced several results in the scalability issues of distributed real-time systems. In particular, we have used our techniques to resolve schedulability issues in distributed systems with end-to-end requirements. During the next year (1997-98), we propose to extend the current work to address the modeling and workload characterization issues in distributed real-time systems. In particular, we propose to investigate the effect of different workload models and component models on the design and the subsequent performance of distributed real-time systems.

  13. Comparing two acromegalic patients with respect to central corneal thickness, intraocular pressure, and tear insulin-like growth factor levels before and after treatment

    PubMed Central

    Emrah, Kan; Elif, Kılıç Kan; Ali, Okuyucu

    2015-01-01

    The aim of the study was to compare the central corneal thickness (CCT), intraocular pressure (IOP), and tear insulin-like growth factor-1 (IGF-1) levels of 2 patients with acromegaly before and after the surgical treatment of the disease. CCTs, IOP levels, and tear IGF-1 values showed a decrease after the treatment in 2 patients. As we found higher CCT, IOP, and tear IGF-1 levels in the active phase of the disease in two acromegaly patients, detailed information about the activity of the disease may be important before the examination of these patients. PMID:26632130

  14. Integrated real-time fracture-diagnostics instrumentation system

    SciTech Connect

    Engi, D

    1983-01-01

    The use of an integrated, real-time fracture-diagnostics instrumentation system for the control of the fracturing treatment during massive hydraulic fracturing is proposed. The proposed system consists of four subsystems: an internal-fracture-pressure measurement system, a fluid-flow measurement system, a borehole seismic system, and a surface-electric-potential measurement system. This use of borehole seismic and surface-electric-potential measurements, which are essentially away-from-the-wellbore measurements, in conjunction with the use of the more commonly used types of measurements, i.e., at-the-wellbore pressure and fluid-flow measurements, is a distinctive feature of the composite real-time diagnostics system. Currently, the real-time capabilities of the individual subsystems are being developed, and the problems associated with their integration into a complete, computer-linked instrumentation system are being addressed. 2 figures.

  15. Effects of Systemic Administration of Dexmedetomidine on Intraocular Pressure and Ocular Perfusion Pressure during Laparoscopic Surgery in a Steep Trendelenburg Position: Prospective, Randomized, Double-Blinded Study

    PubMed Central

    2016-01-01

    Increased intraocular pressure (IOP) during surgery is a risk factor for postoperative ophthalmological complications. We assessed the efficacy of systemically infused dexmedetomidine in preventing the increase in IOP caused by a steep Trendelenburg position, and evaluated the influence of underlying hypertension on IOP during surgery. Sixty patients undergoing laparoscopic surgery in a steep Trendelenburg position were included. Patients in the dexmedetomidine group received a 1.0 µg/kg IV loading dose of dexmedetomidine before anesthesia, followed by an infusion of 0.5 µg/kg/hr throughout the operation. Patients in the saline group were infused with the same volume of normal saline. IOP and ocular perfusion pressure (OPP) were measured 16 times pre- and intraoperatively. In the saline group, IOP increased in the steep Trendelenburg position, and was 11.3 mmHg higher at the end of the time at the position compared with the baseline value (before anesthetic induction). This increase in IOP was attenuated in the dexmedetomidine group, for which IOP was only 4.2 mmHg higher (P < 0.001 vs. the saline group). The steep Trendelenburg position was associated with a decrease in OPP; the degree of decrease was comparable for both groups. In intragroup comparisons between patients with underlying hypertension and normotensive patients, the values of IOP at every time point were comparable. Dexmedetomidine infusion attenuated the increase in IOP during laparoscopic surgery in a steep Trendelenburg position, without further decreasing the OPP. Systemic hypertension did not seem to be associated with any additional increase in IOP during surgery. (Registration at the Clinical Research Information Service of Korea National Institute of Health ID: KCT0001482) PMID:27247511

  16. Effects of topical travoprost 0.004% on intraocular pressure and corneal biomechanical properties in an animal model

    PubMed Central

    Lazcano-Gomez, Gabriel; Ancona-Lezama, David; Gil-Carrasco, Felix; Jimenez-Roman, Jesus

    2016-01-01

    Purpose To determine whether topical application of travoprost 0.004% induces changes in corneal biomechanical properties affecting intraocular pressure (IOP) values in rabbits. Methods Both eyes of 10 New Zealand rabbits were measured 3 times with the Ocular Response Analyzer (ORA) before treatment. Each measurement included corneal hysteresis (CH), corneal resistance factor (CRF), corneal-corrected IOP (IOPcc), and Goldmann equivalent IOP (IOPg). A drop of travoprost 0.004% was applied once daily in right eyes for 3 months; left eyes received no treatments. After 3 months of treatment both eyes of all rabbits were again measured 3 times. After complete keratectomy of both eyes, tissues prepared with hematoxylin-eosin stain were analyzed by means of light microscopy. Results The mean pre- and post-treatment IOPg, respectively, for right eyes was 9.92 ± 5.64 mm Hg and 7.62 ± 2.99 mm Hg (P = 0.027); IOPcc, 19.81 ± 5.25 mm Hg and 17.79 ± 4.09 mm Hg (P = 0.063); CRF, 1.65 ± 1.63 mm Hg and 2.18 ± 2.50 mm Hg (P = 0.266); and CH, 2.79 ± 1.74 mm Hg and 2.64 ± 2.08 mm Hg (P = 0.72). Mean post-treatment right and left eye IOPg values were, respectively, 7.62 ± 2.99 and 10.30 ± 4.40 (P = 0.002); IOPcc, 17.79 ± 4.09 mm Hg and 20.37 ± 4.32 mm Hg (P = 0.009); CRF, 1.65 ± 1.63 mm Hg and 2.17 ± 2.47 mm Hg (P = 0.274); and CH, 2.79 ± 1.74 mm Hg and 2.54 ± 2.08 mm Hg (P = 0.575). No difference in CH and CRF was observed between treated and untreated eyes. Conclusions Post-treatment reduction of IOP in treated eyes was a direct hypotensive effect of travoprost 0.004% and was not affected by changes in corneal biomechanical properties (CH and CRF), resulting in real lower IOP values. PMID:27330476

  17. A new measure of patient satisfaction with ocular hypotensive medications: The Treatment Satisfaction Survey for Intraocular Pressure (TSS-IOP)

    PubMed Central

    Atkinson, Mark J; Stewart, William C; Fain, Joel M; Stewart, Jeanette A; Dhawan, Ravinder; Mozaffari, Essy; Lohs, Jan

    2003-01-01

    Purpose To validate the treatment-specific Treatment Satisfaction Survey for Intraocular Pressure (TSS-IOP). Methods Item content was developed by 4 heterogeneous patient focus groups (n = 32). Instrument validation involved 250 patients on ocular hypotensive medications recruited from ophthalmology practices in the Southern USA. Participants responded to demographic and test questions during a clinic visit. Standard psychometric analyses were performed on the resulting data. Sample Of the 412 patients screened, 253 consented to participate, and 250 provided complete datasets. The sample included 44% male (n = 109), 44% Black (n = 109) and 57% brown eyed (n = 142) participants, with a mean age of 64.6 years (SD 13.1) and a history of elevated IOP for an average of 8.4 yrs (SD 7.8). A majority was receiving monotherapy (60%, n = 151). Results A PC Factor analysis (w/ varimax rotation) of the 31 items yielded 5 factors (Eigenvalues > 1.0) explaining 70% of the total variance. Weaker and conceptually redundant items were removed and the remaining 15 items reanalyzed. The satisfaction factors were; Eye Irritation (EI; 4 items), Convenience of Use (CofU; 3 items), Ease of Use (EofU; 3 items), Hyperemia (HYP; 3 items), and Medication Effectiveness (EFF; 2 items). Chronbach's Alphas ranged from .80 to .86. Greater distributional skew was found for less common experiences (i.e., HYP & EI with 65% & 48.4% ceilings) than for more common experiences (i.e., EofU, CofU, EFF with 10.8%, 20.8% & 15.9% ceilings). TSS-IOP scales converged with conceptually related scales on a previously validated measure of treatment satisfaction, the TSQM (r = .36 to .77). Evidence of concurrent criterion-related validity was found. Patients' symptomatic ratings of eye irritation, hyperemia and difficulties using the medication correlated with satisfaction on these dimensions (r = .30-.56, all p < .001). Clinicians' ratings of IOP control, severity of side effects and problematic medication use

  18. The Effect of Ageing on Ocular Blood Flow, Oxygen Tension and Retinal Function during and after Intraocular Pressure Elevation

    PubMed Central

    Lim, Jeremiah K. H.; Nguyen, Christine T. O.; He, Zheng; Vingrys, Algis J.; Bui, Bang V.

    2014-01-01

    Purpose To investigate the effect of ageing on the recovery of ocular blood flow, intravitreal oxygen tension and retinal function during and after intraocular pressure (IOP) elevation. Methods Long Evans rats (3- and 14-month-old) underwent acute stepwise IOP elevation from 10 to 120 mmHg (5 mmHg steps each 3 minutes). IOP was then returned to baseline and recovery was monitored for 2 hours. Photopic electroretinograms (ERG) were recorded at each IOP step during stress and at each minute during recovery. Ocular blood flow and vitreal oxygen tension (pO2) were assayed continuously and simultaneously using a combined laser Doppler flow meter (LDF) and an oxygen sensitive fibre-optic probe, respectively. The combined sensor was placed in the vitreous chamber, proximal to the retina. Data were binned into 3 minute intervals during stress and 1 min intervals during recovery. Recovery data was described using a bi-logistic function. Results Rats of both ages showed similar susceptibility to IOP elevation, with pO2 showing a closer relationship to ERG than LDF. During recovery, both ages showed a distinctive two-phased recovery for all three measures with the exception of the LDF in 3-month-old rats, which showed only 1 phase. In all animals, LDF recovered fastest (<1 minute), followed by pO2 (<10 minute) and ERG (>1 hour). 14-month-old rats showed surprisingly faster and greater LDF recovery compared to the younger group, with similar levels of pO2 recovery. However, the ERG in these middle-aged animals did not fully recover after two hours, despite showing no difference in susceptibility to IOP during stress compared to the young group. Conclusions Young and middle-aged eyes showed similar susceptibility to IOP elevation in terms of pO2, LDF and ERG. Despite this lack of difference during stress, older eyes did not completely recover function, suggesting a more subtle age-related susceptibility to IOP. PMID:24866182

  19. Intraocular Pressure Measurements Referring to the Corneal Thickness in Keratoconic Eyes After Corneal Crosslinking with Riboflavin and Ultraviolet A

    PubMed Central

    Kasumovic, Sanja Sefic; Mavija, Milka; Kasumovic, Aida; Lepara, Orhan; Duric-Colic, Belkisa; Cabric, Emir; Muhamedagic, Lejla; Sakovic-Racic, Adisa; Jankov, Mirko

    2015-01-01

    Aim: To determine the possible relation between intraocular pressure (IOP), central corneal thickness (CCT) and corneal resistance (CR) in kerotoconic eyes before, 3,6 and 12 months after collagen crosslinking procedure (CXL) with aim to find out does the thicker cornea means already more resistance cornea followed with higher IOP. Methods: Thirty eyes (30 patients) with central keratoconus (KC)were evaluated in retrospective cross sectional study. The corneal biomechanical parameters were taken with Wave Light Allegro Oculyzer produced by Alcon before the CXL, 3, 6 and 12 months after the procedure. IOP were checked by Goldmann applanation tonometry (GAT) before, 3, 6 and 12 months after CXL. Results: The value of IOP before the CXL was 12,0 mmHg (10,62-15,25 mmHg), 3 months later 13,5 mmHg (11,0-16,0 mmHg), 6 months 14,0 mmHg (11,0-16,0 mmHg) and 12 months later 15,0 mmHg (10,37-17,25 mmHg) and was statistically significant higher (p=0,015) comparing to the value of IOP 3 months after the CXL, IOP 12 months after CXL procedure was statistically significant higher comparing to preoperative values (p=0,010). There were no statistically significant difference between the values 3 and 6 months after CXL. The CCT before the CXL procedure was 449 (433-505,75 microns), 3 months after CXL was 420 (383-473microns, p < 0,005), 6 months later 437 (401,25-480,25, p=0,001), 12 months after CXL 437 (401-503 microns, p=0,001). However there is statistically significant difference in CCT 12 months after CXL 437 (401-503microns p=0,032) and the value of CCT 3 months later the procedure (p=0,004) and the CCT 12 months after CXL and the value of CXL 6 months after CXL (p=0,036). The value of CCT did not show any statistically significant difference 3 and 6 months postoperatively. Conclusion: After riboflavin-UVA CXL in eyes with KC there was significant decrease in central corneal thickness 3 and 6 months after the procedure and the thickness is almost the same 12 months later

  20. Eye rubbing-induced changes in intraocular pressure and corneal thickness measured at five locations, in subjects with ocular allergy

    PubMed Central

    Osuagwu, Uchechukwu L.; Alanazi, Saud A.

    2015-01-01

    AIM To assess the effects of eye rubbing on corneal thickness (CT) and intraocular pressure (IOP) measurements obtained 0-30min after habitual eye rubbing in symptomatic patients. METHODS Measurements of IOP and CT were obtained at five locations (central, temporal, superior, nasal and inferior) before, and every 5min for 30min interval after 30s of eye rubbing, for 25 randomly selected eyes of 14 subjects with ocular allergy and 11 age-matched normals. Differences in measurements were calculated in each group [Baseline measurements minus measurements recorded at each time interval after eye rubbing (for IOP), and for each corneal location (for CT)] and comparison were then made between groups (allergic versus control) for differences in any observed effects. RESULTS Within groups, baseline mean IOPs in the allergic patient-group (14.2±3.0 mm Hg) and in the control group (13.1±1.9 mm Hg) were similar at all times, after eye rubbing (P >0.05, for all). The maximum reduction in IOP was 0.8 mm Hg in the control subjects and the maximum increase was also 0.8 mm Hg in the allergic subjects. Between groups (allergic versus control), the changes in IOP remained under 1 mm Hg at all times (P=0.2) after 30min of eye rubbing. Between 0 and 30min of CT measurements after eye rubbing, the mean central CT (CCT), inferior CT (ICT), superior CT (SCT), temporal CT (TCT) and nasal CT (NCT) did not vary significantly from baseline values in the control and allergic-subject groups (P>0.05, for both). Between both groups, changes in CT were similar at all locations (P>0.05) except for the TC which was minimally thinner by about 4.4 µm (P=0.001) in the allergic subjects than in the control subjects, 30min following 30s of eye rubbing. CONCLUSION IOP measured in allergic subjects after 30s of habitual eye rubbing was comparable with that obtained in normal subjects at all times between 0 and 30min. Although, CT in the allergic subjects were similar to those of the control subjects at

  1. Real time programming environment for Windows

    SciTech Connect

    LaBelle, D.R.

    1998-04-01

    This document provides a description of the Real Time Programming Environment (RTProE). RTProE tools allow a programmer to create soft real time projects under general, multi-purpose operating systems. The basic features necessary for real time applications are provided by RTProE, leaving the programmer free to concentrate efforts on his specific project. The current version supports Microsoft Windows{trademark} 95 and NT. The tasks of real time synchronization and communication with other programs are handled by RTProE. RTProE includes a generic method for connecting a graphical user interface (GUI) to allow real time control and interaction with the programmer`s product. Topics covered in this paper include real time performance issues, portability, details of shared memory management, code scheduling, application control, Operating System specific concerns and the use of Computer Aided Software Engineering (CASE) tools. The development of RTProE is an important step in the expansion of the real time programming community. The financial costs associated with using the system are minimal. All source code for RTProE has been made publicly available. Any person with access to a personal computer, Windows 95 or NT, and C or FORTRAN compilers can quickly enter the world of real time modeling and simulation.

  2. Aqueous Angiography: Real-Time and Physiologic Aqueous Humor Outflow Imaging

    PubMed Central

    Saraswathy, Sindhu; Tan, James C. H.; Yu, Fei; Francis, Brian A.; Hinton, David R.; Weinreb, Robert N.; Huang, Alex S.

    2016-01-01

    Purpose Trabecular meshwork (TM) bypass surgeries attempt to enhance aqueous humor outflow (AHO) to lower intraocular pressure (IOP). While TM bypass results are promising, inconsistent success is seen. One hypothesis for this variability rests upon segmental (non-360 degrees uniform) AHO. We describe aqueous angiography as a real-time and physiologic AHO imaging technique in model eyes as a way to simulate live AHO imaging. Methods Pig (n = 46) and human (n = 6) enucleated eyes were obtained, orientated based upon inferior oblique insertion, and pre-perfused with balanced salt solution via a Lewicky AC maintainer through a 1mm side-port. Fluorescein (2.5%) was introduced intracamerally at 10 or 30 mm Hg. With an angiographer, infrared and fluorescent (486 nm) images were acquired. Image processing allowed for collection of pixel information based on intensity or location for statistical analyses. Concurrent OCT was performed, and fixable fluorescent dextrans were introduced into the eye for histological analysis of angiographically active areas. Results Aqueous angiography yielded high quality images with segmental patterns (p<0.0001; Kruskal-Wallis test). No single quadrant was consistently identified as the primary quadrant of angiographic signal (p = 0.06–0.86; Kruskal-Wallis test). Regions of high proximal signal did not necessarily correlate with regions of high distal signal. Angiographically positive but not negative areas demonstrated intrascleral lumens on OCT images. Aqueous angiography with fluorescent dextrans led to their trapping in AHO pathways. Conclusions Aqueous angiography is a real-time and physiologic AHO imaging technique in model eyes. PMID:26807586

  3. Real time mass flow computer for Arc Jet Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Vidal, J.

    1978-01-01

    Experiments at the Arc Jet Tunnel at Ames Research Center have typical run times of 5-10 sec during which the test model is subjected to an environment simulating reentry into Jupiter. Previous real-time determination of mass flow required off-line manual computations from taped or strip chart data. The present paper describes a computer which provides personnel with real-time computations of mass flow. Using an 8-bit microprocessor and standard TTL interface circuitry, the unit interrogates temperature and pressure instruments with other parameters to compute mass flow.

  4. Research of real-time communication software

    NASA Astrophysics Data System (ADS)

    Li, Maotang; Guo, Jingbo; Liu, Yuzhong; Li, Jiahong

    2003-11-01

    Real-time communication has been playing an increasingly important role in our work, life and ocean monitor. With the rapid progress of computer and communication technique as well as the miniaturization of communication system, it is needed to develop the adaptable and reliable real-time communication software in the ocean monitor system. This paper involves the real-time communication software research based on the point-to-point satellite intercommunication system. The object-oriented design method is adopted, which can transmit and receive video data and audio data as well as engineering data by satellite channel. In the real-time communication software, some software modules are developed, which can realize the point-to-point satellite intercommunication in the ocean monitor system. There are three advantages for the real-time communication software. One is that the real-time communication software increases the reliability of the point-to-point satellite intercommunication system working. Second is that some optional parameters are intercalated, which greatly increases the flexibility of the system working. Third is that some hardware is substituted by the real-time communication software, which not only decrease the expense of the system and promotes the miniaturization of communication system, but also aggrandizes the agility of the system.

  5. The ALMA Real Time Control System

    NASA Astrophysics Data System (ADS)

    Kern, Jeffrey S.; Juerges, Thomas A.; Marson, Ralph G.

    2009-01-01

    The Atacama Large Millimeter Array (ALMA) is a revolutionary millimeter and submillimeter array being developed on the Atacama plateau of northern Chile. An international partnership lead by NRAO, ESO, and NAOJ this powerful and flexible telescope will provide unprecedented observations of this relatively unexplored frequency range. The control subsystem for the Atacama Large Millimeter Array must coordinate the monitor and control of at least sixty six antennas (in four different styles), two correlators, and all of the ancillary equipment (samplers, local oscillators, front ends, etc.). This equipment will be spread over tens of kilometers and operated remotely. Operation of the array requires a robust, scalable, and maintainable real time control system. The real time control system is responsible for monitoring and control of any devices where there are fixed deadlines. Examples in the ALMA context are antenna pointing and fringe tracking. Traditionally the real time portion of a large software system is an intricate and error prone portion of the software. As a result the real time portion is very expensive in terms of effort expended both during construction and during maintenance phases of a project. The ALMA real time control system uses a Linux based real time operating system to interact with the hardware and the CORBA based ALMA Common Software to communicate in the distributed computing environment. Mixing the requirements of real time computing and the non-deterministic CORBA middleware has produced an interesting design. We discuss the architecture, design, and implementation of the ALMA real time control system. Highlight some lessons learned along the way, and justify our assertion that this should be the last large scale real time control system in radio astronomy.

  6. Real time sensor for therapeutic radiation delivery

    DOEpatents

    Bliss, Mary; Craig, Richard A.; Reeder, Paul L.

    1998-01-01

    The invention is a real time sensor for therapeutic radiation. A probe is placed in or near the patient that senses in real time the dose at the location of the probe. The strength of the dose is determined by either an insertion or an exit probe. The location is determined by a series of vertical and horizontal sensing elements that gives the operator a real time read out dose location relative to placement of the patient. The increased accuracy prevents serious tissue damage to the patient by preventing overdose or delivery of a dose to a wrong location within the body.

  7. Real time sensor for therapeutic radiation delivery

    DOEpatents

    Bliss, M.; Craig, R.A.; Reeder, P.L.

    1998-01-06

    The invention is a real time sensor for therapeutic radiation. A probe is placed in or near the patient that senses in real time the dose at the location of the probe. The strength of the dose is determined by either an insertion or an exit probe. The location is determined by a series of vertical and horizontal sensing elements that gives the operator a real time read out dose location relative to placement of the patient. The increased accuracy prevents serious tissue damage to the patient by preventing overdose or delivery of a dose to a wrong location within the body. 14 figs.

  8. Real-time monitoring of landslides

    USGS Publications Warehouse

    Reid, Mark E.; LaHusen, Richard G.; Baum, Rex L.; Kean, Jason W.; Schulz, William H.; Highland, Lynn M.

    2012-01-01

    Landslides cause fatalities and property damage throughout the Nation. To reduce the impact from hazardous landslides, the U.S. Geological Survey develops and uses real-time and near-real-time landslide monitoring systems. Monitoring can detect when hillslopes are primed for sliding and can provide early indications of rapid, catastrophic movement. Continuous information from up-to-the-minute or real-time monitoring provides prompt notification of landslide activity, advances our understanding of landslide behavior, and enables more effective engineering and planning efforts.

  9. Real-time medical applications and telecommunications.

    PubMed

    Stravs, M

    1999-01-01

    Telecommunications play an important role in telemedicine. Many forms of telecommunication services based on different telecommunication technologies are developed for various needs. The paper deals with complex real-time applications which demand high telecommunication requirements. At the beginning, medical applications are categorised and real-time applications qualified as multimedia applications. Requirements for multimedia elements are listed separately. Later on, short introduction of related telecommunication protocols is given. Real-time medical applications can show their ability in case of guaranteed quality of services delivered by telecommunication network as it is explained in the end.

  10. REAL-TIME TRACER MONITORING OF RESERVOIR STIMULATION PROCEDURES

    SciTech Connect

    George Scott III

    2002-08-01

    Ongoing Phase 2 work comprises the development and field-testing of a real-time reservoir stimulation diagnostic system. Phase 3 work commenced in June 2001, and involved conducting research, development and field-testing of real-time enhanced dual-fluid stimulation processes. Experimental field-testing to date includes three well tests. Application of these real-time stimulation processes and diagnostic technologies has been technically successful with commercial production from the ''marginal'' reservoirs in the first two well tests. The third well test proved downhole-mixing is an efficient process for acid stimulation of a carbonate reservoir that produced oil and gas with 2200 psi bottomhole reservoir pressure, however, subsequent shut-in pressure testing indicated the reservoir was characterized by low-permeability. Realtimezone continues to seek patent protection in foreign markets to the benefit of both RTZ and NETL. Realtimezone and the NETL have licensed the United States patented to Halliburton Energy Services (HES). Ongoing Phase 2 and Phase 3 field-testing continues to confirm applications of both real-time technologies, from well testing conducted over the last 12-month work period and including well test scheduled for year-end of 2002. Technical data transfer to industry is ongoing via Internet tech-transfer, public presentations and industry publications. Final Phase 3 test work will be focused on further field-testing the innovational process of blending stimulation fluids downhole. This system provides a number of advantages in comparison to older industry fracturing techniques and allows the operator to control reservoir fracture propagation and concentrations of proppant placed in the reservoir, in real-time. Another observed advantage is that lower friction pressures result, which results in lower pump treating pressures and safer reservoir hydraulic fracturing jobs.

  11. The dark phase intraocular pressure elevation and retinal ganglion cell degeneration in a rat model of experimental glaucoma.

    PubMed

    Kwong, Jacky M K; Vo, Nancy; Quan, Ann; Nam, Michael; Kyung, Haksu; Yu, Fei; Piri, Natik; Caprioli, Joseph

    2013-07-01

    Intraocular pressure (IOP) elevation is considered as a major risk factor causing the progression of vision deterioration in glaucoma. Although it is known that the IOP level changes widely throughout the day and night, how the dark or light phase IOP elevation contributes to retinal ganglion cell (RGC) degeneration is still largely unclear. To examine the profile of IOP, modified laser photocoagulation was applied to the trabecular meshwork of Brown Norway rats and both light and dark phase IOPs were monitored approximately 1-2 times a week. The relationship between IOP elevation and RGC degeneration was investigated while RGC body loss was analyzed with Rbpms immunolabeling on retinal wholemount and axonal injury in the optic nerve was semi-quantified. The baseline awake dark and light IOPs were 30.4 ± 2.7 and 20.2 ± 2.1 mmHg respectively. The average dark IOP was increased to 38.2 ± 3.2 mmHg for five weeks after the laser treatment on 270° trabecular meshwork. However, there was no significant loss of RGC body and axonal injury. After laser treatment on 330° trabecular meshwork, the dark and light IOPs were significantly increased to 43.8 ± 4.6 and 23 ± 3.7 mmHg respectively for 5 weeks. The cumulative dark and light IOP elevations were 277 ± 86 and 113 ± 50 mmHg days respectively while the cumulative total (light and dark) IOP elevation was 213 ± 114 mmHg days. After 5 weeks, regional RGC body loss of 29.5 ± 15.5% and moderate axonal injury were observed. Axonal injury and loss of RGC body had a high correlation with the cumulative total IOP elevation (R(2) = 0.60 and 0.65 respectively). There was an association between the cumulative dark IOP elevation and RGC body loss (R(2) = 0.37) and axonal injury (R(2) = 0.51) whereas the associations between neuronal damages and the cumulative light IOP elevation were weak (for RGC body loss, R(2) = 0.01; for axonal injury, R(2) = 0.26). Simple linear regression model

  12. Nonpsychotropic cannabinoids, abnormal cannabidiol and canabigerol-dimethyl heptyl, act at novel cannabinoid receptors to reduce intraocular pressure.

    PubMed

    Szczesniak, Anna-Maria; Maor, Yehoshua; Robertson, Harold; Hung, Orlando; Kelly, Melanie E M

    2011-10-01

    The objective of our study was to examine the pharmacology of the intraocular pressure (IOP)-lowering actions of the behaviorally inactive cannabinoids, abnormal cannabidiol (abn-CBD), and a cannabigerol analog, cannabigerol-dimethyl heptyl (CBG-DMH), in comparison to that of the nonselective cannabinoid 1 receptor (CB(1)R) and CB(2)R agonist, WIN55,212-2, in Brown Norway rats. The IOP was measured noninvasively using a hand-held tonometer in nonanesthetized animals. The IOP measurements were taken every 15 min for a period of 2 h after drug administration. All drugs were administered via intraperitoneal (i.p.) injections, and abn-CBD and CBG-DMH were also given topically. Both abn-CBD and CBG-DMH reduced IOP when administrated i.p. at doses of ≥2.5 mg/kg or topically at concentrations of 1%-2%. The IOP-lowering effects of abn-CBD and CBG-DMH were reduced by i.p. administration of O-1918 (2.5 mg/kg), a selective antagonist of the abn-CBD-sensitive cannabinoid-related receptor (CBx), but were unaffected by the CB(1)R antagonist, AM251 (2.5 mg/kg), or the CB(2)R antagonist, AM630 (2.5 mg/kg). In contrast, the IOP-lowering action of WIN55,212-2 was completely blocked by the CB(1)R-selective antagonist, AM251, and was unaffected by the CBx receptor antagonist, O-1918. However, similar to the nonpsychotropic cannabinoids, the ocular hypotensive actions of WIN55,212-2 were also insensitive to block by the CB(2)R antagonist, AM630. Consistent with this, the selective CB(2)R agonist, HU-308 (2 mg/kg) failed to reduce IOP in Brown Norway rats. Concurrent application of a dose of WIN55,212-2 that was subthreshold to reduce IOP (0.25 mg/kg), together with a topical dose of either abn-CBD (0.5%) or CBG-DMH (0.25%), respectively, potentiated the ocular hypotensive effect of either compound applied alone. This study demonstrates that the atypical cannabinoid, abn-CBD, and the cannabigerol analog, CBG-DMH, decrease IOP in the normotensive Brown Norway rat eye independent of CB

  13. Real-time smart fluorescence sensor platform

    NASA Astrophysics Data System (ADS)

    Dickens, Jason E.; Vaughn, Mike S.; Taylor, Mervin; Ponstingl, Mike

    2011-06-01

    A novel compact LED array based light induced fluorescence (LIF) sensor has been developed for real-time in-line monitoring of intrinsic fluorophores in the solid and liquid state. The sensor is essential for on-the-spot, routine, and cost effective real-time analysis. The sensor is designed to provide real-time emission response along with various smart sensing parameters to ensure real-time measurement quality that is required for regulated GMP process monitoring applications. This work describes a LIF sensor tailored for solid-phase fluorometry. Fundamental figures of merit, excitation overexposure and smart sensing features required for modern process monitoring and control are discussed within the context of pharmaceutical solid-phase manufacturing and similar applications.

  14. The LAA real-time benchmarks

    SciTech Connect

    Block, R.K.; Krischer, W.; Lone, S.

    1989-04-01

    In the context of the LAA detector development program a subgroup Real Time Data Processing has tackled the problem of intelligent triggering. The main goal of this group is to show how fast digital devices, implemented as custom-made or commercial processors, can execute some basic algorithms, and how they can be embedded in the data flow between detector readout components and fully programmable commercial processors, which are expected to be the final data processing filter in real time.

  15. Real-time scheduling using minimum search

    NASA Technical Reports Server (NTRS)

    Tadepalli, Prasad; Joshi, Varad

    1992-01-01

    In this paper we consider a simple model of real-time scheduling. We present a real-time scheduling system called RTS which is based on Korf's Minimin algorithm. Experimental results show that the schedule quality initially improves with the amount of look-ahead search and tapers off quickly. So it sppears that reasonably good schedules can be produced with a relatively shallow search.

  16. Processing PCM Data in Real Time

    NASA Technical Reports Server (NTRS)

    Wissink, T. L.

    1982-01-01

    Novel hardware configuration makes it possible for Space Shuttle launch processing system to monitor pulse-code-modulated data in real time. Using two microprogramable "option planes," incoming PCM data are monitored for changes at rate of one frame of data (80 16-bit words) every 10 milliseconds. Real-time PCM processor utilizes CPU in mini-computer and CPU's in two option planes.

  17. Interferometer real time control development for SIM

    NASA Astrophysics Data System (ADS)

    Bell, Charles E.

    2003-02-01

    Real Time Control (RTC) for the Space Interferometry Mission will build on the real time core interferometer control technology under development at JPL since the mid 1990s, with heritage from the ground based MKII and Palomar Testbed Interferometer projects developed in the late '80s and early '90s. The core software and electronics technology for SIM interferometer real time control is successfully operating on several SIM technology demonstration testbeds, including the Real-time Interferometer Control System Testbed, System Testbed-3, and the Microarcsecond Metrology testbed. This paper provides an overview of the architecture, design, integration, and test of the SIM flight interferometer real time control to meet challenging flight system requirements for the high processor throughput, low-latency interconnect, and precise synchronization to support microarcsecond-level astrometric measurements for greater than five years at 1 AU in Earth-trailing orbit. The electronics and software architecture of the interferometer real time control core and its adaptation to a flight design concept are described. Control loops for pointing and pathlength control within each of four flight interferometers and for coordination of control and data across interferometers are illustrated. The nature of onboard data processing to fit average downlink rates while retaining post-processed astrometric measurement precision and accuracy is also addressed. Interferometer flight software will be developed using a software simulation environment incorporating models of the metrology and starlight sensors and actuators to close the real time control loops. RTC flight software and instrument flight electronics will in turn be integrated utilizing the same simulation architecture for metrology and starlight component models to close real time control loops and verify RTC functionality and performance prior to delivery to flight interferometer system integration at Lockheed Martin

  18. Analysis of real-time vibration data

    USGS Publications Warehouse

    Safak, E.

    2005-01-01

    In recent years, a few structures have been instrumented to provide continuous vibration data in real time, recording not only large-amplitude motions generated by extreme loads, but also small-amplitude motions generated by ambient loads. The main objective in continuous recording is to track any changes in structural characteristics, and to detect damage after an extreme event, such as an earthquake or explosion. The Fourier-based spectral analysis methods have been the primary tool to analyze vibration data from structures. In general, such methods do not work well for real-time data, because real-time data are mainly composed of ambient vibrations with very low amplitudes and signal-to-noise ratios. The long duration, linearity, and the stationarity of ambient data, however, allow us to utilize statistical signal processing tools, which can compensate for the adverse effects of low amplitudes and high noise. The analysis of real-time data requires tools and techniques that can be applied in real-time; i.e., data are processed and analyzed while being acquired. This paper presents some of the basic tools and techniques for processing and analyzing real-time vibration data. The topics discussed include utilization of running time windows, tracking mean and mean-square values, filtering, system identification, and damage detection.

  19. REAL TIME SYSTEM OPERATIONS 2006-2007

    SciTech Connect

    Eto, Joseph H.; Parashar, Manu; Lewis, Nancy Jo

    2008-08-15

    The Real Time System Operations (RTSO) 2006-2007 project focused on two parallel technical tasks: (1) Real-Time Applications of Phasors for Monitoring, Alarming and Control; and (2) Real-Time Voltage Security Assessment (RTVSA) Prototype Tool. The overall goal of the phasor applications project was to accelerate adoption and foster greater use of new, more accurate, time-synchronized phasor measurements by conducting research and prototyping applications on California ISO's phasor platform - Real-Time Dynamics Monitoring System (RTDMS) -- that provide previously unavailable information on the dynamic stability of the grid. Feasibility assessment studies were conducted on potential application of this technology for small-signal stability monitoring, validating/improving existing stability nomograms, conducting frequency response analysis, and obtaining real-time sensitivity information on key metrics to assess grid stress. Based on study findings, prototype applications for real-time visualization and alarming, small-signal stability monitoring, measurement based sensitivity analysis and frequency response assessment were developed, factory- and field-tested at the California ISO and at BPA. The goal of the RTVSA project was to provide California ISO with a prototype voltage security assessment tool that runs in real time within California ISO?s new reliability and congestion management system. CERTS conducted a technical assessment of appropriate algorithms, developed a prototype incorporating state-of-art algorithms (such as the continuation power flow, direct method, boundary orbiting method, and hyperplanes) into a framework most suitable for an operations environment. Based on study findings, a functional specification was prepared, which the California ISO has since used to procure a production-quality tool that is now a part of a suite of advanced computational tools that is used by California ISO for reliability and congestion management.

  20. Characterization of real-time computers

    NASA Technical Reports Server (NTRS)

    Shin, K. G.; Krishna, C. M.

    1984-01-01

    A real-time system consists of a computer controller and controlled processes. Despite the synergistic relationship between these two components, they have been traditionally designed and analyzed independently of and separately from each other; namely, computer controllers by computer scientists/engineers and controlled processes by control scientists. As a remedy for this problem, in this report real-time computers are characterized by performance measures based on computer controller response time that are: (1) congruent to the real-time applications, (2) able to offer an objective comparison of rival computer systems, and (3) experimentally measurable/determinable. These measures, unlike others, provide the real-time computer controller with a natural link to controlled processes. In order to demonstrate their utility and power, these measures are first determined for example controlled processes on the basis of control performance functionals. They are then used for two important real-time multiprocessor design applications - the number-power tradeoff and fault-masking and synchronization.

  1. Visualization of Real-Time Data

    NASA Technical Reports Server (NTRS)

    Stansifer, Ryan; Engrand, Peter

    1996-01-01

    In this project we explored various approaches to presenting real-time data from the numerous systems monitored on the space shuttle to computer users. We examined the approach that several projects at the Kennedy Space Center (KSC) used to accomplish this. We undertook to build a prototype system to demonstrate that the Internet and the Java programming language could be used to present the real-time data conveniently. Several Java programs were developed that presented real-time data in different forms including one form that emulated the display screens of the PC GOAL system which is familiar to many at KSC. Also, we developed several communications programs to supply the data continuously. Furthermore, a framework was created using the World Wide Web (WWW) to organize the collection and presentation of the real-time data. We believe our demonstration project shows the great flexibility of the approach. We had no particular use of the data in mind, instead we wanted the most general and the least complex framework possible. People who wish to view data need only know how to use a WWW browser and the address (the URL). People wanting to build WWW documents containing real-time data need only know the values of a few parameters, they do not need to program in Java or any other language. These are stunning advantages over more monolithic systems.

  2. Real-time enhanced vision system

    NASA Astrophysics Data System (ADS)

    Hines, Glenn D.; Rahman, Zia-ur; Jobson, Daniel J.; Woodell, Glenn A.; Harrah, Steven D.

    2005-05-01

    Flying in poor visibility conditions, such as rain, snow, fog or haze, is inherently dangerous. However these conditions can occur at nearly any location, so inevitably pilots must successfully navigate through them. At NASA Langley Research Center (LaRC), under support of the Aviation Safety and Security Program Office and the Systems Engineering Directorate, we are developing an Enhanced Vision System (EVS) that combines image enhancement and synthetic vision elements to assist pilots flying through adverse weather conditions. This system uses a combination of forward-looking infrared and visible sensors for data acquisition. A core function of the system is to enhance and fuse the sensor data in order to increase the information content and quality of the captured imagery. These operations must be performed in real-time for the pilot to use while flying. For image enhancement, we are using the LaRC patented Retinex algorithm since it performs exceptionally well for improving low-contrast range imagery typically seen during poor visibility poor visibility conditions. In general, real-time operation of the Retinex requires specialized hardware. To date, we have successfully implemented a single-sensor real-time version of the Retinex on several different Digital Signal Processor (DSP) platforms. In this paper we give an overview of the EVS and its performance requirements for real-time enhancement and fusion and we discuss our current real-time Retinex implementations on DSPs.

  3. Real-time Enhanced Vision System

    NASA Technical Reports Server (NTRS)

    Hines, Glenn D.; Rahman, Zia-Ur; Jobson, Daniel J.; Woodell, Glenn A.; Harrah, Steven D.

    2005-01-01

    Flying in poor visibility conditions, such as rain, snow, fog or haze, is inherently dangerous. However these conditions can occur at nearly any location, so inevitably pilots must successfully navigate through them. At NASA Langley Research Center (LaRC), under support of the Aviation Safety and Security Program Office and the Systems Engineering Directorate, we are developing an Enhanced Vision System (EVS) that combines image enhancement and synthetic vision elements to assist pilots flying through adverse weather conditions. This system uses a combination of forward-looking infrared and visible sensors for data acquisition. A core function of the system is to enhance and fuse the sensor data in order to increase the information content and quality of the captured imagery. These operations must be performed in real-time for the pilot to use while flying. For image enhancement, we are using the LaRC patented Retinex algorithm since it performs exceptionally well for improving low-contrast range imagery typically seen during poor visibility conditions. In general, real-time operation of the Retinex requires specialized hardware. To date, we have successfully implemented a single-sensor real-time version of the Retinex on several different Digital Signal Processor (DSP) platforms. In this paper we give an overview of the EVS and its performance requirements for real-time enhancement and fusion and we discuss our current real-time Retinex implementations on DSPs.

  4. Really computing nonperturbative real time correlation functions

    NASA Astrophysics Data System (ADS)

    Bödeker, Dietrich; McLerran, Larry; Smilga, Andrei

    1995-10-01

    It has been argued by Grigoriev and Rubakov that one can simulate real time processes involving baryon number nonconservation at high temperature using real time evolution of classical equations, and summing over initial conditions with a classical thermal weight. It is known that such a naive algorithm is plagued by ultraviolet divergences. In quantum theory the divergences are regularized, but the corresponding graphs involve the contributions from the hard momentum region and also the new scale ~gT comes into play. We propose a modified algorithm which involves solving the classical equations of motion for the effective hard thermal loop Hamiltonian with an ultraviolet cutoff μ>>gT and integrating over initial conditions with a proper thermal weight. Such an algorithm should provide a determination of the infrared behavior of the real time correlation function T determining the baryon violation rate. Hopefully, the results obtained in this modified algorithm will be cutoff independent.

  5. Continuous, real time microwave plasma element sensor

    DOEpatents

    Woskov, P.P.; Smatlak, D.L.; Cohn, D.R.; Wittle, J.K.; Titus, C.H.; Surma, J.E.

    1995-12-26

    Microwave-induced plasma is described for continuous, real time trace element monitoring under harsh and variable conditions. The sensor includes a source of high power microwave energy and a shorted waveguide made of a microwave conductive, refractory material communicating with the source of the microwave energy to generate a plasma. The high power waveguide is constructed to be robust in a hot, hostile environment. It includes an aperture for the passage of gases to be analyzed and a spectrometer is connected to receive light from the plasma. Provision is made for real time in situ calibration. The spectrometer disperses the light, which is then analyzed by a computer. The sensor is capable of making continuous, real time quantitative measurements of desired elements, such as the heavy metals lead and mercury. 3 figs.

  6. Continuous, real time microwave plasma element sensor

    DOEpatents

    Woskov, Paul P.; Smatlak, Donna L.; Cohn, Daniel R.; Wittle, J. Kenneth; Titus, Charles H.; Surma, Jeffrey E.

    1995-01-01

    Microwave-induced plasma for continuous, real time trace element monitoring under harsh and variable conditions. The sensor includes a source of high power microwave energy and a shorted waveguide made of a microwave conductive, refractory material communicating with the source of the microwave energy to generate a plasma. The high power waveguide is constructed to be robust in a hot, hostile environment. It includes an aperture for the passage of gases to be analyzed and a spectrometer is connected to receive light from the plasma. Provision is made for real time in situ calibration. The spectrometer disperses the light, which is then analyzed by a computer. The sensor is capable of making continuous, real time quantitative measurements of desired elements, such as the heavy metals lead and mercury.

  7. Real-time, high frequency QRS electrocardiograph

    NASA Technical Reports Server (NTRS)

    Schlegel, Todd T. (Inventor); DePalma, Jude L. (Inventor); Moradi, Saeed (Inventor)

    2006-01-01

    Real time cardiac electrical data are received from a patient, manipulated to determine various useful aspects of the ECG signal, and displayed in real time in a useful form on a computer screen or monitor. The monitor displays the high frequency data from the QRS complex in units of microvolts, juxtaposed with a display of conventional ECG data in units of millivolts or microvolts. The high frequency data are analyzed for their root mean square (RMS) voltage values and the discrete RMS values and related parameters are displayed in real time. The high frequency data from the QRS complex are analyzed with imbedded algorithms to determine the presence or absence of reduced amplitude zones, referred to herein as RAZs. RAZs are displayed as go, no-go signals on the computer monitor. The RMS and related values of the high frequency components are displayed as time varying signals, and the presence or absence of RAZs may be similarly displayed over time.

  8. Durham adaptive optics real-time controller.

    PubMed

    Basden, Alastair; Geng, Deli; Myers, Richard; Younger, Eddy

    2010-11-10

    The Durham adaptive optics (AO) real-time controller was initially a proof of concept design for a generic AO control system. It has since been developed into a modern and powerful central-processing-unit-based real-time control system, capable of using hardware acceleration (including field programmable gate arrays and graphical processing units), based primarily around commercial off-the-shelf hardware. It is powerful enough to be used as the real-time controller for all currently planned 8 m class telescope AO systems. Here we give details of this controller and the concepts behind it, and report on performance, including latency and jitter, which is less than 10 μs for small AO systems.

  9. Real-time DNA microarray analysis

    PubMed Central

    Hassibi, Arjang; Vikalo, Haris; Riechmann, José Luis; Hassibi, Babak

    2009-01-01

    We present a quantification method for affinity-based DNA microarrays which is based on the real-time measurements of hybridization kinetics. This method, i.e. real-time DNA microarrays, enhances the detection dynamic range of conventional systems by being impervious to probe saturation in the capturing spots, washing artifacts, microarray spot-to-spot variations, and other signal amplitude-affecting non-idealities. We demonstrate in both theory and practice that the time-constant of target capturing in microarrays, similar to all affinity-based biosensors, is inversely proportional to the concentration of the target analyte, which we subsequently use as the fundamental parameter to estimate the concentration of the analytes. Furthermore, to empirically validate the capabilities of this method in practical applications, we present a FRET-based assay which enables the real-time detection in gene expression DNA microarrays. PMID:19723688

  10. Real-time DNA microarray analysis.

    PubMed

    Hassibi, Arjang; Vikalo, Haris; Riechmann, José Luis; Hassibi, Babak

    2009-11-01

    We present a quantification method for affinity-based DNA microarrays which is based on the real-time measurements of hybridization kinetics. This method, i.e. real-time DNA microarrays, enhances the detection dynamic range of conventional systems by being impervious to probe saturation in the capturing spots, washing artifacts, microarray spot-to-spot variations, and other signal amplitude-affecting non-idealities. We demonstrate in both theory and practice that the time-constant of target capturing in microarrays, similar to all affinity-based biosensors, is inversely proportional to the concentration of the target analyte, which we subsequently use as the fundamental parameter to estimate the concentration of the analytes. Furthermore, to empirically validate the capabilities of this method in practical applications, we present a FRET-based assay which enables the real-time detection in gene expression DNA microarrays. PMID:19723688

  11. Real-Time Visualization of Tissue Ischemia

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Chrien, Thomas D. (Inventor); Eastwood, Michael L. (Inventor)

    2000-01-01

    A real-time display of tissue ischemia which comprises three CCD video cameras, each with a narrow bandwidth filter at the correct wavelength is discussed. The cameras simultaneously view an area of tissue suspected of having ischemic areas through beamsplitters. The output from each camera is adjusted to give the correct signal intensity for combining with, the others into an image for display. If necessary a digital signal processor (DSP) can implement algorithms for image enhancement prior to display. Current DSP engines are fast enough to give real-time display. Measurement at three, wavelengths, combined into a real-time Red-Green-Blue (RGB) video display with a digital signal processing (DSP) board to implement image algorithms, provides direct visualization of ischemic areas.

  12. The real-time Neutron Monitor database

    NASA Astrophysics Data System (ADS)

    Klein, K.-L.; Steigies, C.; Nmdb Team

    2009-04-01

    In January 2007 the Real time database for high-resolution neutron monitor measurements (NMDB) project, which is supported by the 7th framework program of the European Commission, commenced. One year after the project start we have several neutron monitor stations that are sending their data in real-time to a publicly available prototype database in a common format. We have developed applications that make use of the real-time cosmic ray measurements for example for space weather applications and dose calculations at airplane altitudes. We are also in the process of establishing a public outreach site and a training site with material for university students and researchers and engineers who want to get familiar with cosmic rays and neutron monitor measurements. An overview of the project status as well as instructions on how to use the available data will be given. Possible future developments will be briefly discussed.

  13. Real-time inspection by submarine images

    NASA Astrophysics Data System (ADS)

    Tascini, Guido; Zingaretti, Primo; Conte, Giuseppe

    1996-10-01

    A real-time application of computer vision concerning tracking and inspection of a submarine pipeline is described. The objective is to develop automatic procedures for supporting human operators in the real-time analysis of images acquired by means of cameras mounted on underwater remotely operated vehicles (ROV) Implementation of such procedures gives rise to a human-machine system for underwater pipeline inspection that can automatically detect and signal the presence of the pipe, of its structural or accessory elements, and of dangerous or alien objects in its neighborhood. The possibility of modifying the image acquisition rate in the simulations performed on video- recorded images is used to prove that the system performs all necessary processing with an acceptable robustness working in real-time up to a speed of about 2.5 kn, widely greater than that the actual ROVs and the security features allow.

  14. Test of Real-Time Space Weather Predictors

    NASA Astrophysics Data System (ADS)

    Reiff, P. H.; Bala, R.

    2013-12-01

    We are testing four real-time empirical space weather prediction functions to see which has been most successful, running in real time, for the past two years. Data from the "Wing Model" (presently running at SWPC in Boulder); the "Boyle Model" have been running in real time for a number of years, with the Boyle Index given online with alerts since 2003. The "Ram Model" and the "Newell Model" (also running at Rice University) have all been providing Kp predictions in real time for one year. We are testing their relative effectiveness in predicting Kp, and also their "up time", by using their actual predictions posted in real time against the final version Kp values. The Boyle model is a neural network model with 12-hour lookback time, using the Boyle Index as the base function, and yields one-hour and three-hour ahead predictions. The Ram model is similar to the Boyle model, but adds a pressure term to the base function. The Newell model is also a 12-hour neural net, but using the Newell function as its base. The Wing model gives a one- and four-hour prediction, with the prediction time variable with the solar wind velocity. All three Rice models are available in real time at http://mms.rice.edu/realtime/forecast.html , and the Wing model at http://www.swpc.noaa.gov/wingkp/ . Early results indicate that any of the three Rice neural net predictors had a slightly better success rate in predicting Kp in real time than Wing. In the image below from August 1-7, 2013, Wing's correlation coefficient was 0.682, with three hours of missing data (shown as -1). The Boyle function's correlation coefficient was 0.782, the Ram function was 0.788 and the Newell function was 0.793. In addition, Wing's prediction has missing data more often (roughly 1% over a year of data) than the Rice predictions (roughly 0.1% over a year of data), meaning it had less reliability. All of the models could successfully predict one hour-ahead Kp, on average, to better than one step in Kp, and the

  15. Quantitative Real-Time PCR: Recent Advances.

    PubMed

    Singh, Charanjeet; Roy-Chowdhuri, Sinchita

    2016-01-01

    Quantitative real-time polymerase chain reaction is a technique for simultaneous amplification and product quantification of a target DNA as the process takes place in real time in a "closed-tube" system. Although this technique can provide an absolute quantification of the initial template copy number, quantification relative to a control sample or second sequence is typically adequate. The quantification process employs melting curve analysis and/or fluorescent detection systems and can provide amplification and genotyping in a relatively short time. Here we describe the properties and uses of various fluorescent detection systems used for quantification. PMID:26843055

  16. Imaging of living cells in real time

    NASA Astrophysics Data System (ADS)

    Tychinsky, Vladimir P.; Koufal, Georgy E.; Perevedentseva, Elena V.; Vyshenskaia, Tatiana V.; Nikandrov, Serguei L.

    1996-12-01

    Parameters of intrinsic cell motility is one of the cell activity characteristics which can be measured in real-time. For evaluation of certain organelles velocity we propose to use high sensitivity of computer-aided phase microscope airyscan to local phase changes connected with refractive index. This method is based on periodical scanning of cell profile in direction perpendicular to organelles movement. Analysis of the obtained 2-dimensional time-coordinate matrix allows us to define organelle velocity in quasi-real time and areas of cell activity. The experiments with onion cells confirm the method applicability for cell activity investigation.

  17. Software Package For Real-Time Graphics

    NASA Technical Reports Server (NTRS)

    Malone, Jacqueline C.; Moore, Archie L.

    1991-01-01

    Software package for master graphics interactive console (MAGIC) at Western Aeronautical Test Range (WATR) of NASA Ames Research Center provides general-purpose graphical display system for real-time and post-real-time analysis of data. Written in C language and intended for use on workstation of interactive raster imaging system (IRIS) equipped with level-V Unix operating system. Enables flight researchers to create their own displays on basis of individual requirements. Applicable to monitoring of complicated processes in chemical industry.

  18. Real-Time, Interactive Sonic Boom Display

    NASA Technical Reports Server (NTRS)

    Haering, Jr., Edward A. (Inventor); Plotkin, Kenneth J. (Inventor)

    2012-01-01

    The present invention is an improved real-time, interactive sonic boom display for aircraft. By using physical properties obtained via various sensors and databases, the invention determines, in real-time, sonic boom impacts locations and intensities for aircraft traveling at supersonic speeds. The information is provided to a pilot via a display that lists a selectable set of maneuvers available to the pilot to mitigate sonic boom issues. Upon selection of a maneuver, the information as to the result of the maneuver is displayed and the pilot may proceed with making the maneuver, or provide new data to the system in order to calculate a different maneuver.

  19. Real-Time Occupancy Change Analyzer

    2005-03-30

    The Real-Time Occupancy Change Analyzer (ROCA) produces an occupancy grid map of an environment around the robot, scans the environment to generate a current obstacle map relative to a current robot position, and converts the current obstacle map to a current occupancy grid map. Changes in the occupancy grid can be reported in real time to support a number of tracking capabilities. The benefit of ROCA is that rather than only providing a vector tomore » the detected change, it provides the actual x,y position of the change.« less

  20. Axial Tomography from Digitized Real Time Radiography

    DOE R&D Accomplishments Database

    Zolnay, A. S.; McDonald, W. M.; Doupont, P. A.; McKinney, R. L.; Lee, M. M.

    1985-01-18

    Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

  1. Automated real-time software development

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.; Walker, Carrie K.; Turkovich, John J.

    1993-01-01

    A Computer-Aided Software Engineering (CASE) system has been developed at the Charles Stark Draper Laboratory (CSDL) under the direction of the NASA Langley Research Center. The CSDL CASE tool provides an automated method of generating source code and hard copy documentation from functional application engineering specifications. The goal is to significantly reduce the cost of developing and maintaining real-time scientific and engineering software while increasing system reliability. This paper describes CSDL CASE and discusses demonstrations that used the tool to automatically generate real-time application code.

  2. Real-time evaporimeter/hygrometer

    NASA Astrophysics Data System (ADS)

    Knopp, Jerome; Smiglewski, Leonard T.

    1998-07-01

    Laboratory measurements of microscopic level changes in a water tank were shown to have good correlation with the evaporation rate predicted using Dalton's Law. Submicron level changes in the tank were measured in real-time using an interferometer interfaced to a PC. The methodology developed offers a way to build an instrument that can be used as a standard for an evaporimeter or a hygrometer. The real-time measurement capability provides a tool for determining refined dynamic correlations of evaporation with fast changes in meteorological variables such as wind and solar radiation.

  3. Quantitative Real-Time PCR: Recent Advances.

    PubMed

    Singh, Charanjeet; Roy-Chowdhuri, Sinchita

    2016-01-01

    Quantitative real-time polymerase chain reaction is a technique for simultaneous amplification and product quantification of a target DNA as the process takes place in real time in a "closed-tube" system. Although this technique can provide an absolute quantification of the initial template copy number, quantification relative to a control sample or second sequence is typically adequate. The quantification process employs melting curve analysis and/or fluorescent detection systems and can provide amplification and genotyping in a relatively short time. Here we describe the properties and uses of various fluorescent detection systems used for quantification.

  4. Machine vision for real time orbital operations

    NASA Technical Reports Server (NTRS)

    Vinz, Frank L.

    1988-01-01

    Machine vision for automation and robotic operation of Space Station era systems has the potential for increasing the efficiency of orbital servicing, repair, assembly and docking tasks. A machine vision research project is described in which a TV camera is used for inputing visual data to a computer so that image processing may be achieved for real time control of these orbital operations. A technique has resulted from this research which reduces computer memory requirements and greatly increases typical computational speed such that it has the potential for development into a real time orbital machine vision system. This technique is called AI BOSS (Analysis of Images by Box Scan and Syntax).

  5. Comparing the efficacy of the monocular trial treatment paradigm with multiple measurements of intraocular pressure before and after treatment initiation in primary open-angle glaucoma.

    PubMed

    Krishna, Rohit; Debry, Peter W; Waldman, Corey W; Koulen, Peter

    2012-01-01

    The monocular trial has been proposed as a test to help control for diurnal fluctuations in eye pressure when assessing medication effectiveness. We undertook a prospective study to determine the sensitivity and specificity of the monocular trial as a test for determining the effectiveness of a glaucoma medication. The efficacy of the monocular trial was compared to the diagnostic paradigm of repeated pre- and post-treatment measurements in determining whether an intraocular pressure (IOP)-lowering drug is effective. Forty-two patients with newly diagnosed open-angle glaucoma completed five visits: visit 1 for determining eligibility, obtaining consent, and measuring IOP, visit 2 for a second pressure measurement, and visit 3 for a third pressure reading. The new medication was then started in one eye. IOP measurements were made at weeks 4 and 6. The gold standard IOP change was defined as the difference in mean between the pre- and post-medication visits. A medication was deemed effective if this difference was at least 15%. The monocular trial pressure change was defined as the IOP change in the treated eye between the visit immediately before and immediately after the medication addition, corrected by subtracting the pressure change in the untreated eye. All 42 patients completed the full protocol with good compliance. Twenty-five of 42 (60%) medication additions were considered effective by the gold standard method, and 25/42 (60%) by the monocular trial method. However, the two methods agreed in only 26 patients (17 Yes/Yes, 9 No/No). The calculated sensitivity was low (0.68), with a specificity of 0.53. The monocular trial can give useful clues as to whether a medication is effective, but should not be the only information used in making this determination. To obtain the most valid results, multiple pressure checks should be done before and after starting a new medication.

  6. Real-Time Blackboards For Sensor Fusions

    NASA Astrophysics Data System (ADS)

    Johnson, Donald H.; Shaw, Scott W.; Reynolds, Steven; Himayat, Nageen

    1989-09-01

    Multi-sensor fusion, at the most basic level, can be cast into a concise, elegant model. Reality demands, however, that this model be modified and augmented. These modifications often result in software systems that are confusing in function and difficult to debug. This problem can be ameliorated by adopting an object-oriented, data-flow programming style. For real-time applications, this approach simplifies data communications and storage management. The concept of object-oriented, data-flow programming is conveniently embodied in the black-board style of software architecture. Blackboard systems allow diverse programs access to a central data base. When the blackboard is described as an object, it can be distributed over multiple processors for real-time applications. Choosing the appropriate parallel architecture is the subject of ongoing research. A prototype blackboard has been constructed to fuse optical image regions and Doppler radar events. The system maintains tracks of simulated targets in real time. The results of this simulation have been used to direct further research on real-time blackboard systems.

  7. Real-time cleaning performance feedback

    SciTech Connect

    Meltzer, M.

    1994-12-01

    Monitoring contamination levels on parts during cleaning operations will provide feedback that can be useful in reducing waste generation and air emissions caused by over- or under-cleaning. Such real-time process controls can help eliminate pollution in a wide variety of industries, including aerospace, electronics, and metal finishing.

  8. OPAD-EDIFIS Real-Time Processing

    NASA Technical Reports Server (NTRS)

    Katsinis, Constantine

    1997-01-01

    The Optical Plume Anomaly Detection (OPAD) detects engine hardware degradation of flight vehicles through identification and quantification of elemental species found in the plume by analyzing the plume emission spectra in a real-time mode. Real-time performance of OPAD relies on extensive software which must report metal amounts in the plume faster than once every 0.5 sec. OPAD software previously written by NASA scientists performed most necessary functions at speeds which were far below what is needed for real-time operation. The research presented in this report improved the execution speed of the software by optimizing the code without changing the algorithms and converting it into a parallelized form which is executed in a shared-memory multiprocessor system. The resulting code was subjected to extensive timing analysis. The report also provides suggestions for further performance improvement by (1) identifying areas of algorithm optimization, (2) recommending commercially available multiprocessor architectures and operating systems to support real-time execution and (3) presenting an initial study of fault-tolerance requirements.

  9. REAL TIME CONTROL OF URBAN DRAINAGE NETWORKS

    EPA Science Inventory

    Real-time control (RTC) is a custom-designed, computer-assisted management technology for a specific sewerage network to meet the operational objectives of its collection/conveyance system. RTC can operate in several modes, including a mode that is activated during a wet weather ...

  10. Real Time Grid Reliability Management 2005

    SciTech Connect

    Eto, Joe; Eto, Joe; Lesieutre, Bernard; Lewis, Nancy Jo; Parashar, Manu

    2008-07-07

    The increased need to manage California?s electricity grid in real time is a result of the ongoing transition from a system operated by vertically-integrated utilities serving native loads to one operated by an independent system operator supporting competitive energy markets. During this transition period, the traditional approach to reliability management -- construction of new transmission lines -- has not been pursued due to unresolved issues related to the financing and recovery of transmission project costs. In the absence of investments in new transmission infrastructure, the best strategy for managing reliability is to equip system operators with better real-time information about actual operating margins so that they can better understand and manage the risk of operating closer to the edge. A companion strategy is to address known deficiencies in offline modeling tools that are needed to ground the use of improved real-time tools. This project: (1) developed and conducted first-ever demonstrations of two prototype real-time software tools for voltage security assessment and phasor monitoring; and (2) prepared a scoping study on improving load and generator response models. Additional funding through two separate subsequent work authorizations has already been provided to build upon the work initiated in this project.

  11. The Power of Real-Time PCR

    ERIC Educational Resources Information Center

    Valasek, Mark A.; Repa, Joyce J.

    2005-01-01

    In recent years, real-time polymerase chain reaction (PCR) has emerged as a robust and widely used methodology for biological investigation because it can detect and quantify very small amounts of specific nucleic acid sequences. As a research tool, a major application of this technology is the rapid and accurate assessment of changes in gene…

  12. Real Time Estimation Of Object Spectrocolorimettic Features

    NASA Astrophysics Data System (ADS)

    Petrov, Peter V.; Lukarsky, Christo D.; Christov, Victor V.; Grancharov, Parashkev A.; Arshinkova, Iren I.

    1989-03-01

    The results obtained in the development of a laboratory prototype of intelligent spectrometric system with real time digital signal processing are shown in this paper. The system is acombination of visible range spectrophotometer and focussing holographic grid with photodiode linear structure, i.e.the sensor, real time digital signal processing controller and display processor for gray level visualization, together with PC/XT controlLing computer. The twodimesional adaptive differential pulse code modulator with simultaneous correction of sensor dark current introduced into the real time controller allows the registration of measurments with resolution of 10 bit/el and real time data compression 2.5 times. During computation of colorimetric estimations or wideband photo-metric compression the possibilities for express analysis increase together with the enhancement of the signal-to-noise ratio. The system control and the visualization of spectral and colorimetric features in the data flux is made with personal computer together with display processor with resolution 512x512x8 and interactive software. It may be used for ground-based and onboard complexes.

  13. Feedback as Real-Time Constructions

    ERIC Educational Resources Information Center

    Keiding, Tina Bering; Qvortrup, Ane

    2014-01-01

    This article offers a re-description of feedback and the significance of time in feedback constructions based on systems theory. It describes feedback as internal, real-time constructions in a learning system. From this perspective, feedback is neither immediate nor delayed, but occurs in the very moment it takes place. This article argues for a…

  14. Real-time PCR detection chemistry.

    PubMed

    Navarro, E; Serrano-Heras, G; Castaño, M J; Solera, J

    2015-01-15

    Real-time PCR is the method of choice in many laboratories for diagnostic and food applications. This technology merges the polymerase chain reaction chemistry with the use of fluorescent reporter molecules in order to monitor the production of amplification products during each cycle of the PCR reaction. Thus, the combination of excellent sensitivity and specificity, reproducible data, low contamination risk and reduced hand-on time, which make it a post-PCR analysis unnecessary, has made real-time PCR technology an appealing alternative to conventional PCR. The present paper attempts to provide a rigorous overview of fluorescent-based methods for nucleic acid analysis in real-time PCR described in the literature so far. Herein, different real-time PCR chemistries have been classified into two main groups; the first group comprises double-stranded DNA intercalating molecules, such as SYBR Green I and EvaGreen, whereas the second includes fluorophore-labeled oligonucleotides. The latter, in turn, has been divided into three subgroups according to the type of fluorescent molecules used in the PCR reaction: (i) primer-probes (Scorpions, Amplifluor, LUX, Cyclicons, Angler); (ii) probes; hydrolysis (TaqMan, MGB-TaqMan, Snake assay) and hybridization (Hybprobe or FRET, Molecular Beacons, HyBeacon, MGB-Pleiades, MGB-Eclipse, ResonSense, Yin-Yang or displacing); and (iii) analogues of nucleic acids (PNA, LNA, ZNA, non-natural bases: Plexor primer, Tiny-Molecular Beacon). In addition, structures, mechanisms of action, advantages and applications of such real-time PCR probes and analogues are depicted in this review.

  15. Alfaxalone versus propofol in dogs: a randomised trial to assess effects on peri-induction tear production, intraocular pressure and globe position.

    PubMed

    Costa, Daniel; Leiva, Marta; Moll, Xavier; Aguilar, Adrià; Peña, Teresa; Andaluz, Anna

    2015-01-17

    The purpose of this randomised trial was to compare the effects of alfaxalone and propofol on tear production (STT-1), intraocular pressure (IOP) and globe position (GP) in healthy dogs. Fourteen Beagles were randomly divided into two groups; dogs in one group received alfaxalone (3 mg/kg) (n=7) and dogs in the other group received propofol (6 mg/kg) (n=7), both administered intravenously. IOP and GP were evaluated at basal time (Tb) and T2,5,10,15,20,25&30 (minutes after complete drug administration). STT-1 was evaluated at Tb and T10,20&30. STT-1 and IOP results were analysed using analysis of variance and GP was analysed using the likelihood ratio χ(2) test. Dogs in the alfaxalone group showed a significant reduction in STT-1 at T10&20 (P<0.05), while the propofol group did not show statistically significant differences in this parameter over time. Both anaesthetic drugs produced a transient elevation of IOP at T2 (P>0.05), which then decreased (P<0.01). While alfaxalone caused a ventral globe deviation that lasted from T2 to T10 (P<0.05) and was fully recovered at T30, propofol induced a ventral globe deviation from T2 to T5 (P<0.05), being restored at T20. These results suggest that both alfaxalone and propofol can be safely used for intraocular surgery, as they significantly reduce IOP. Furthermore, anaesthetic induction with propofol would be especially recommended for dogs with tear deficiencies. PMID:25324218

  16. Real-Time Earthquake Analysis for Disaster Mitigation (READI) Network

    NASA Astrophysics Data System (ADS)

    Bock, Y.

    2014-12-01

    Real-time GNSS networks are making a significant impact on our ability to forecast, assess, and mitigate the effects of geological hazards. I describe the activities of the Real-time Earthquake Analysis for Disaster Mitigation (READI) working group. The group leverages 600+ real-time GPS stations in western North America operated by UNAVCO (PBO network), Central Washington University (PANGA), US Geological Survey & Scripps Institution of Oceanography (SCIGN project), UC Berkeley & US Geological Survey (BARD network), and the Pacific Geosciences Centre (WCDA project). Our goal is to demonstrate an earthquake and tsunami early warning system for western North America. Rapid response is particularly important for those coastal communities that are in the near-source region of large earthquakes and may have only minutes of warning time, and who today are not adequately covered by existing seismic and basin-wide ocean-buoy monitoring systems. The READI working group is performing comparisons of independent real time analyses of 1 Hz GPS data for station displacements and is participating in government-sponsored earthquake and tsunami exercises in the Western U.S. I describe a prototype seismogeodetic system using a cluster of southern California stations that includes GNSS tracking and collocation with MEMS accelerometers for real-time estimation of seismic velocity and displacement waveforms, which has advantages for improved earthquake early warning and tsunami forecasts compared to seismic-only or GPS-only methods. The READI working group's ultimate goal is to participate in an Indo-Pacific Tsunami early warning system that utilizes GNSS real-time displacements and ionospheric measurements along with seismic, near-shore buoys and ocean-bottom pressure sensors, where available, to rapidly estimate magnitude and finite fault slip models for large earthquakes, and then forecast tsunami source, energy scale, geographic extent, inundation and runup. This will require

  17. ALMA Correlator Real-Time Data Processor

    NASA Astrophysics Data System (ADS)

    Pisano, J.; Amestica, R.; Perez, J.

    2005-10-01

    The design of a real-time Linux application utilizing Real-Time Application Interface (RTAI) to process real-time data from the radio astronomy correlator for the Atacama Large Millimeter Array (ALMA) is described. The correlator is a custom-built digital signal processor which computes the cross-correlation function of two digitized signal streams. ALMA will have 64 antennas with 2080 signal streams each with a sample rate of 4 giga-samples per second. The correlator's aggregate data output will be 1 gigabyte per second. The software is defined by hard deadlines with high input and processing data rates, while requiring interfaces to non real-time external computers. The designed computer system - the Correlator Data Processor or CDP, consists of a cluster of 17 SMP computers, 16 of which are compute nodes plus a master controller node all running real-time Linux kernels. Each compute node uses an RTAI kernel module to interface to a 32-bit parallel interface which accepts raw data at 64 megabytes per second in 1 megabyte chunks every 16 milliseconds. These data are transferred to tasks running on multiple CPUs in hard real-time using RTAI's LXRT facility to perform quantization corrections, data windowing, FFTs, and phase corrections for a processing rate of approximately 1 GFLOPS. Highly accurate timing signals are distributed to all seventeen computer nodes in order to synchronize them to other time-dependent devices in the observatory array. RTAI kernel tasks interface to the timing signals providing sub-millisecond timing resolution. The CDP interfaces, via the master node, to other computer systems on an external intra-net for command and control, data storage, and further data (image) processing. The master node accesses these external systems utilizing ALMA Common Software (ACS), a CORBA-based client-server software infrastructure providing logging, monitoring, data delivery, and intra-computer function invocation. The software is being developed in tandem

  18. Real-Time Seismology in Portugal

    NASA Astrophysics Data System (ADS)

    Custodio, S.; Marreiros, C.; Carvalho, S.; Vales, D.; Lima, V.; Carrilho, F.

    2012-12-01

    Portugal is located next to the plate boundary between Eurasia (Iberia) and Africa (Nubia). The country has been repeatedly affected by some of the largest earthquakes, both onshore and offshore, in the historical European record, including the largest historical European earthquake, the great Lisbon earthquake of 1755 (~M8.5). The Portuguese territory has suffered directly the consequences of strong ground shaking (collapse of buildings, etc) and also some of the most destructive consequences of earthquakes (e.g. tsunamis, fires, etc). However, the rate of tectonic deformation in the Portuguese territory is low (the Eurasian-African plates converge at a rate of ~ 5 mm/yr), which results in long recurrence intervals between earthquakes. This low to moderate rate of seismic activity has two major negative effects: 1) it is difficult to study the regional seismo-tectonics with traditional passive methods; 2) the population is little aware of earthquake risk and unprepared to react in case of disaster. In this scenario, real-time seismology is key to monitoring earthquake crisis in real-time, providing early warnings about potentially destructive events, and assisting in the channeling of recovery efforts in case of disaster. In this paper we will present the real-time algorithms implemented at Instituto de Meteorologia (IM), the institution responsible for seismic monitoring in Portugal. In particular, we will focus on the following aspects: 1) Data collection and real-time transmission to the headquarters. Broadband seismological stations are owned and operated by five different institutions. The last years have witnessed an effort for integration, and presently most data arrives at IM lab in real-time. 2) Earthquake location and local magnitude determination. Data is automatically analyzed in order to obtain a first earthquake hypocenter and ML. While this process is mostly automatic, it still requires the revision by an operator, who is available 24h. 3

  19. Real-time imaging of quantum entanglement.

    PubMed

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

    2013-01-01

    Quantum Entanglement is widely regarded as one of the most prominent features of quantum mechanics and quantum information science. Although, photonic entanglement is routinely studied in many experiments nowadays, its signature has been out of the grasp for real-time imaging. Here we show that modern technology, namely triggered intensified charge coupled device (ICCD) cameras are fast and sensitive enough to image in real-time the effect of the measurement of one photon on its entangled partner. To quantitatively verify the non-classicality of the measurements we determine the detected photon number and error margin from the registered intensity image within a certain region. Additionally, the use of the ICCD camera allows us to demonstrate the high flexibility of the setup in creating any desired spatial-mode entanglement, which suggests as well that visual imaging in quantum optics not only provides a better intuitive understanding of entanglement but will improve applications of quantum science.

  20. Real Time Radiation Exposure And Health Risks

    NASA Technical Reports Server (NTRS)

    Hu, Shaowen; Barzilla, Janet E.; Semones, Edward J.

    2015-01-01

    Radiation from solar particle events (SPEs) poses a serious threat to future manned missions outside of low Earth orbit (LEO). Accurate characterization of the radiation environment in the inner heliosphere and timely monitoring the health risks to crew are essential steps to ensure the safety of future Mars missions. In this project we plan to develop an approach that can use the particle data from multiple satellites and perform near real-time simulations of radiation exposure and health risks for various exposure scenarios. Time-course profiles of dose rates will be calculated with HZETRN and PDOSE from the energy spectrum and compositions of the particles archived from satellites, and will be validated from recent radiation exposure measurements in space. Real-time estimation of radiation risks will be investigated using ARRBOD. This cross discipline integrated approach can improve risk mitigation by providing critical information for risk assessment and medical guidance to crew during SPEs.

  1. Real time gamma-ray signature identifier

    DOEpatents

    Rowland, Mark; Gosnell, Tom B.; Ham, Cheryl; Perkins, Dwight; Wong, James

    2012-05-15

    A real time gamma-ray signature/source identification method and system using principal components analysis (PCA) for transforming and substantially reducing one or more comprehensive spectral libraries of nuclear materials types and configurations into a corresponding concise representation/signature(s) representing and indexing each individual predetermined spectrum in principal component (PC) space, wherein an unknown gamma-ray signature may be compared against the representative signature to find a match or at least characterize the unknown signature from among all the entries in the library with a single regression or simple projection into the PC space, so as to substantially reduce processing time and computing resources and enable real-time characterization and/or identification.

  2. Real Time Radiation Monitoring Using Nanotechnology

    NASA Technical Reports Server (NTRS)

    Li, Jing (Inventor); Wilkins, Richard T. (Inventor); Hanratty, James J. (Inventor); Lu, Yijiang (Inventor)

    2016-01-01

    System and method for monitoring receipt and estimating flux value, in real time, of incident radiation, using two or more nanostructures (NSs) and associated terminals to provide closed electrical paths and to measure one or more electrical property change values .DELTA.EPV, associated with irradiated NSs, during a sequence of irradiation time intervals. Effects of irradiation, without healing and with healing, of the NSs, are separately modeled for first order and second order healing. Change values.DELTA.EPV are related to flux, to cumulative dose received by NSs, and to radiation and healing effectivity parameters and/or.mu., associated with the NS material and to the flux. Flux and/or dose are estimated in real time, based on EPV change values, using measured .DELTA.EPV values. Threshold dose for specified changes of biological origin (usually undesired) can be estimated. Effects of time-dependent radiation flux are analyzed in pre-healing and healing regimes.

  3. Real time radiography of Titan 4 booster

    NASA Astrophysics Data System (ADS)

    Lachapell, M.; Turner, D.; Dolan, K.; Perkins, D.; Costerus, B.

    1993-04-01

    Lawrence Livermore National Laboratory successfully completed a real-time radiography of the Titan 4 booster motor in February 1993. The success of this project depended on the quick response to Air Force criteria and securing a multi-disciplinary team addressing the numerous technical challenges. The team's challenges included the following: large area imager design and fabrication problems; vibrating mitigation obstacles; sound mitigation dilemmas; high levels of fail safe confidence; and operating a fragile, transportable x-ray linear accelerator. The data was viewed in real-time and stored utilizing standard video hardware. The data from the test is presently being analyzed. The multi-disciplinary team was presented with many serious technical challenges that needed to be addressed expeditiously. The purpose of this paper is to examine some of the technical issues and how they were executed.

  4. Real time animation of space plasma phenomena

    NASA Technical Reports Server (NTRS)

    Jordan, K. F.; Greenstadt, E. W.

    1987-01-01

    In pursuit of real time animation of computer simulated space plasma phenomena, the code was rewritten for the Massively Parallel Processor (MPP). The program creates a dynamic representation of the global bowshock which is based on actual spacecraft data and designed for three dimensional graphic output. This output consists of time slice sequences which make up the frames of the animation. With the MPP, 16384, 512 or 4 frames can be calculated simultaneously depending upon which characteristic is being computed. The run time was greatly reduced which promotes the rapid sequence of images and makes real time animation a foreseeable goal. The addition of more complex phenomenology in the constructed computer images is now possible and work proceeds to generate these images.

  5. Real-Time Gauge/Gravity Duality

    SciTech Connect

    Skenderis, Kostas; Rees, Balt C. van

    2008-08-22

    We present a general prescription for the holographic computation of real-time n-point functions in nontrivial states. In quantum field theory such real-time computations involve a choice of a time contour in the complex time plane. The holographic prescription amounts to 'filling in' this contour with bulk solutions: real segments of the contour are filled in with Lorentzian solutions while imaginary segments are filled in with Riemannian solutions and appropriate matching conditions are imposed at the corners of the contour. We illustrate the general discussion by computing the 2-point function of a scalar operator using this prescription and by showing that this leads to an unambiguous answer with the correct i{epsilon} insertions.

  6. Visualizations for Real-time Pricing Demonstration

    SciTech Connect

    Marinovici, Maria C.; Hammerstrom, Janelle L.; Widergren, Steven E.; Dayley, Greg K.

    2014-10-13

    In this paper, the visualization tools created for monitoring the operations of a real-time pricing demonstration system that runs at a distribution feeder level are presented. The information these tools provide gives insights into demand behavior from automated price responsive devices, distribution feeder characteristics, impact of weather on system’s development, and other significant dynamics. Given the large number of devices that bid into a feeder-level real-time electricity market, new techniques are explored to summarize the present state of the system and contrast that with previous trends as well as future projections. To better understand the system behavior and correctly inform decision-making procedures, effective visualization of the data is imperative.

  7. AMON: Transition to real-time operations

    NASA Astrophysics Data System (ADS)

    Cowen, D. F.; Keivani, A.; Tešić, G.

    2016-04-01

    The Astrophysical Multimessenger Observatory Network (AMON) will link the world's leading high-energy neutrino, cosmic-ray, gamma-ray and gravitational wave observatories by performing real-time coincidence searches for multimessenger sources from observatories' subthreshold data streams. The resulting coincidences will be distributed to interested parties in the form of electronic alerts for real-time follow-up observation. We will present the science case, design elements, current and projected partner observatories, status of the AMON project, and an initial AMON-enabled analysis. The prototype of the AMON server has been online since August 2014 and processing archival data. Currently, we are deploying new high-uptime servers and will be ready to start issuing alerts as early as winter 2015/16.

  8. System Equivalent for Real Time Digital Simulator

    NASA Astrophysics Data System (ADS)

    Lin, Xi

    2011-07-01

    The purpose of this research is to develop a method of making system equivalents for the Real Time Digital Simulator (RTDS), which should enhance its capability of simulating large power systems. The proposed equivalent combines a Frequency Dependent Network Equivalent (FDNE) for the high frequency electromagnetic transients and a Transient Stability Analysis (TSA) type simulation block for the electromechanical transients. The frequency dependent characteristic for FDNE is obtained by curve-fitting frequency domain admittance characteristics using the Vector Fitting method. An approach for approximating the frequency dependent characteristic of large power networks from readily available typical power-flow data is also introduced. A new scheme of incorporating TSA solution in RTDS is proposed. This report shows how the TSA algorithm can be adapted to a real time platform. The validity of this method is confirmed with examples, including the study of a multi in-feed HVDC system based network.

  9. "Fast" Is Not "Real-Time": Designing Effective Real-Time AI Systems

    NASA Astrophysics Data System (ADS)

    O'Reilly, Cindy A.; Cromarty, Andrew S.

    1985-04-01

    Realistic practical problem domains (such as robotics, process control, and certain kinds of signal processing) stand to benefit greatly from the application of artificial intelligence techniques. These problem domains are of special interest because they are typified by complex dynamic environments in which the ability to select and initiate a proper response to environmental events in real time is a strict prerequisite to effective environmental interaction. Artificial intelligence systems developed to date have been sheltered from this real-time requirement, however, largely by virtue of their use of simplified problem domains or problem representations. The plethora of colloquial and (in general) mutually inconsistent interpretations of the term "real-time" employed by workers in each of these domains further exacerbates the difficul-ties in effectively applying state-of-the-art problem solving tech-niques to time-critical problems. Indeed, the intellectual waters are by now sufficiently muddied that the pursuit of a rigorous treatment of intelligent real-time performance mandates the redevelopment of proper problem perspective on what "real-time" means, starting from first principles. We present a simple but nonetheless formal definition of real-time performance. We then undertake an analysis of both conventional techniques and AI technology with respect to their ability to meet substantive real-time performance criteria. This analysis provides a basis for specification of problem-independent design requirements for systems that would claim real-time performance. Finally, we discuss the application of these design principles to a pragmatic problem in real-time signal understanding.

  10. CRTF Real-Time Aperture Flux system

    SciTech Connect

    Davis, D.B.

    1980-01-01

    The Real-Time Aperture Flux system (TRAF) is a test measurement system designed to determine the input power/unit area (flux density) during solar experiments conducted at the Central Receiver Test Facility, Sandia National Laboratories, Albuquerque, New Mexico. The RTAF is capable of using both thermal sensors and photon sensors to determine the flux densities in the RTAF measuring plane. These data are manipulated in various ways to derive input power and flux density distribution to solar experiments.

  11. Thermal imaging with real time picture presentation.

    PubMed

    Borg, S B

    1968-09-01

    The accomplishment of thermal imaging with real-time picture presentation represents a significant advance in nondestructive testing. Described here is the AGA Thermovision, capable of producing such imaging. Operating principles, basic features, and recording techniques are reviewed, and a survey is made of the range of applications. Examples include electrical power distribution elements, a turbine blade, and a missile model in a wind tunnel.

  12. Real-Time Clinical Monitoring of Biomolecules

    NASA Astrophysics Data System (ADS)

    Rogers, Michelle L.; Boutelle, Martyn G.

    2013-06-01

    Continuous monitoring of clinical biomarkers offers the exciting possibility of new therapies that use biomarker levels to guide treatment in real time. This review explores recent progress toward this goal. We initially consider measurements in body fluids by a range of analytical methods. We then discuss direct tissue measurements performed by implanted sensors; sampling techniques, including microdialysis and ultrafiltration; and noninvasive methods. A future directions section considers analytical methods at the cusp of clinical use.

  13. Real-Time X-Ray Inspection

    NASA Technical Reports Server (NTRS)

    Bulthuis, Ronald V.

    1988-01-01

    X-ray imaging instrument adapted to continuous scanning. Modern version of fluoroscope enables rapid x-ray inspection of parts. Developed for detection of buckling in insulated ducts. Uses radiation from radioactive gadolinium or thallium source. Instrument weighs only 6 1/2 lb. Quickly scanned by hand along duct surface, providing real-time image. Based on Lixiscope, developed at Goddard Space Flight Center.

  14. Real-time interactive treatment planning.

    PubMed

    Otto, Karl

    2014-09-01

    The goal of this work is to develop an interactive treatment planning platform that permits real-time manipulation of dose distributions including DVHs and other dose metrics. The hypothesis underlying the approach proposed here is that the process of evaluating potential dose distribution options and deciding on the best clinical trade-offs may be separated from the derivation of the actual delivery parameters used for the patient's treatment. For this purpose a novel algorithm for deriving an Achievable Dose Estimate (ADE) was developed. The ADE algorithm is computationally efficient so as to update dose distributions in effectively real-time while accurately incorporating the limits of what can be achieved in practice. The resulting system is a software environment for interactive real-time manipulation of dose that permits the clinician to rapidly develop a fully customized 3D dose distribution. Graphical navigation of dose distributions is achieved by a sophisticated method of identifying contributing fluence elements, modifying those elements and re-computing the entire dose distribution. 3D dose distributions are calculated in ~2-20 ms. Including graphics processing overhead, clinicians may visually interact with the dose distribution (e.g. 'drag' a DVH) and display updates of the dose distribution at a rate of more than 20 times per second. Preliminary testing on various sites shows that interactive planning may be completed in ~1-5 min, depending on the complexity of the case (number of targets and OARs). Final DVHs are derived through a separate plan optimization step using a conventional VMAT planning system and were shown to be achievable within 2% and 4% in high and low dose regions respectively. With real-time interactive planning trade-offs between Target(s) and OARs may be evaluated efficiently providing a better understanding of the dosimetric options available to each patient in static or adaptive RT.

  15. Software Analyzes Complex Systems in Real Time

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Expert system software programs, also known as knowledge-based systems, are computer programs that emulate the knowledge and analytical skills of one or more human experts, related to a specific subject. SHINE (Spacecraft Health Inference Engine) is one such program, a software inference engine (expert system) designed by NASA for the purpose of monitoring, analyzing, and diagnosing both real-time and non-real-time systems. It was developed to meet many of the Agency s demanding and rigorous artificial intelligence goals for current and future needs. NASA developed the sophisticated and reusable software based on the experience and requirements of its Jet Propulsion Laboratory s (JPL) Artificial Intelligence Research Group in developing expert systems for space flight operations specifically, the diagnosis of spacecraft health. It was designed to be efficient enough to operate in demanding real time and in limited hardware environments, and to be utilized by non-expert systems applications written in conventional programming languages. The technology is currently used in several ongoing NASA applications, including the Mars Exploration Rovers and the Spacecraft Health Automatic Reasoning Pilot (SHARP) program for the diagnosis of telecommunication anomalies during the Neptune Voyager Encounter. It is also finding applications outside of the Space Agency.

  16. Real-time monitoring system for microfluidics

    NASA Astrophysics Data System (ADS)

    Sapuppo, F.; Cantelli, G.; Fortuna, L.; Arena, P.; Bucolo, M.

    2007-05-01

    A new non-invasive real-time system for the monitoring and control of microfluidodynamic phenomena is proposed. The general purpose design of such system is suitable for in vitro and in vivo experimental setup and therefore for microfluidic application in the biomedical field such as lab-on-chip and for research studies in the field of microcirculation. The system consists of an ad hoc optical setup for image magnification providing images suitable for image acquisition and processing. The optic system was designed and developed using discrete opto-mechanic components mounted on a breadboard in order to provide an optic path accessible at any point where the information needs to be acquired. The optic sensing, acquisition, and processing were performed using an integrated vision system based on the Cellular Nonlinear Networks (CNNs) analogic technology called Focal Plane Processor (FPP, Eye-RIS, Anafocus) and inserted in the optic path. Ad hoc algorithms were implemented for the real-time analysis and extraction of fluido-dynamic parameters in micro-channels. They were tested on images recorded during in vivo microcirculation experiments on hamsters and then they were applied on images optically acquired and processed in real-time during in vitro experiments on a continuous microfluidic device (serpentine mixer, ThinXXS) with a two-phase fluid.

  17. Turning movement estimation in real time

    SciTech Connect

    Martin, P.T.

    1997-08-01

    Fast processors offer exciting opportunities for real-time traffic monitoring. Conventional transportation planning models that assume stable and predictable travel patterns do not lend themselves to on-line traffic forecasting. This paper describes how a new traffic flow inference model has the potential to determine comprehensive flow information in real time. Its philosophical basis is borrowed from the field of operational research, where it has been used for optimizing water and electricity flows. This paper shows how road traffic turning movement flows can be estimated from link detected flows at small recurrent intervals, in real time. The paper details the formulation of the problem, outlines the structure of the data set that provides the detector data for the model input and observed turning flows for the model evaluation. The theoretical principles that define the model are described briefly. Turning movement flow estimates, at 5-min intervals, from two independent surveys are presented and analyzed. The results show an overall mean coefficient of determination (r{sup 2}) of 79--82% between observed and modeled turning movement flows.

  18. Steering a mobile robot in real time

    NASA Astrophysics Data System (ADS)

    Chuah, Mei C.; Fennema, Claude L., Jr.

    1994-10-01

    Using computer vision for mobile robot navigation has been of interest since the 1960s. This interest is evident in even the earliest robot projects: at SRI International (`Shakey') and at the Stanford University (`Stanford Cart'). These pioneering projects provided a foundation for late work but fell far short of providing real time solutions. Since the mid 1980s, the ARPA sponsored ALV and UGV projects have established a need for real time navigation. To achieve the necessary speed, some researchers have focused on building faster hardware; others have turned to the use of new computational architectures, such as neural nets. The work described in this paper uses another approach that has become known as `perceptual servoing.' Previously reported results show that perceptual servoing is both fast and accurate when used to steer vehicles equipped with precise odometers. When the instrumentation on the vehicle does not give precise measurements of distance traveled, as could be the case for a vehicle traveling on ice or mud, new techniques are required to accommodate the reduced ability to make accurate predictions about motion and control. This paper presents a method that computes estimates of distance traveled using landmarks and path information. The new method continues to perform in real time using modest computational facilities, and results demonstrate the effects of the new implementation on steering accuracy.

  19. Real-time optical image processing techniques

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang

    1988-01-01

    Nonlinear real-time optical processing on spatial pulse frequency modulation has been pursued through the analysis, design, and fabrication of pulse frequency modulated halftone screens and the modification of micro-channel spatial light modulators (MSLMs). Micro-channel spatial light modulators are modified via the Fabry-Perot method to achieve the high gamma operation required for non-linear operation. Real-time nonlinear processing was performed using the halftone screen and MSLM. The experiments showed the effectiveness of the thresholding and also showed the needs of higher SBP for image processing. The Hughes LCLV has been characterized and found to yield high gamma (about 1.7) when operated in low frequency and low bias mode. Cascading of two LCLVs should also provide enough gamma for nonlinear processing. In this case, the SBP of the LCLV is sufficient but the uniformity of the LCLV needs improvement. These include image correlation, computer generation of holograms, pseudo-color image encoding for image enhancement, and associative-retrieval in neural processing. The discovery of the only known optical method for dynamic range compression of an input image in real-time by using GaAs photorefractive crystals is reported. Finally, a new architecture for non-linear multiple sensory, neural processing has been suggested.

  20. Real-time Tsunami Inundation Prediction Using High Performance Computers

    NASA Astrophysics Data System (ADS)

    Oishi, Y.; Imamura, F.; Sugawara, D.

    2014-12-01

    Recently off-shore tsunami observation stations based on cabled ocean bottom pressure gauges are actively being deployed especially in Japan. These cabled systems are designed to provide real-time tsunami data before tsunamis reach coastlines for disaster mitigation purposes. To receive real benefits of these observations, real-time analysis techniques to make an effective use of these data are necessary. A representative study was made by Tsushima et al. (2009) that proposed a method to provide instant tsunami source prediction based on achieving tsunami waveform data. As time passes, the prediction is improved by using updated waveform data. After a tsunami source is predicted, tsunami waveforms are synthesized from pre-computed tsunami Green functions of linear long wave equations. Tsushima et al. (2014) updated the method by combining the tsunami waveform inversion with an instant inversion of coseismic crustal deformation and improved the prediction accuracy and speed in the early stages. For disaster mitigation purposes, real-time predictions of tsunami inundation are also important. In this study, we discuss the possibility of real-time tsunami inundation predictions, which require faster-than-real-time tsunami inundation simulation in addition to instant tsunami source analysis. Although the computational amount is large to solve non-linear shallow water equations for inundation predictions, it has become executable through the recent developments of high performance computing technologies. We conducted parallel computations of tsunami inundation and achieved 6.0 TFLOPS by using 19,000 CPU cores. We employed a leap-frog finite difference method with nested staggered grids of which resolution range from 405 m to 5 m. The resolution ratio of each nested domain was 1/3. Total number of grid points were 13 million, and the time step was 0.1 seconds. Tsunami sources of 2011 Tohoku-oki earthquake were tested. The inundation prediction up to 2 hours after the

  1. Acting to gain information: Real-time reasoning meets real-time perception

    NASA Technical Reports Server (NTRS)

    Rosenschein, Stan

    1994-01-01

    Recent advances in intelligent reactive systems suggest new approaches to the problem of deriving task-relevant information from perceptual systems in real time. The author will describe work in progress aimed at coupling intelligent control mechanisms to real-time perception systems, with special emphasis on frame rate visual measurement systems. A model for integrated reasoning and perception will be discussed, and recent progress in applying these ideas to problems of sensor utilization for efficient recognition and tracking will be described.

  2. Slimhole early kick detection by real-time drilling analysis

    SciTech Connect

    Swanson, B.W.; Gardner, A.G.; Brown, N.P.; Murray, P.J.

    1997-03-01

    Early kick detection has been identified as being of primary importance in slimhole wellbores. Small annular volumes means that, to maintain the integrity of the well, allowable kick volumes must be small. Gas influxes must therefore be detected and shut in rapidly. This paper describes an early kick-detection system developed for slimholes to detect and confirm the presence of an influx rapidly. This system has been run successfully on a number of slimhole operations. The early kick-detection (EKD) system is based on real-time analysis of drilling data obtained directly from a comprehensive mud-logging system on the rig. The analysis technique compares predictions of mud flow out and standpipe pressure from a dynamic wellbore model with corresponding values from the rig. The predicted values are derived from a model driven in real time by rig data such as pump rate and pipe rotation rate. Kick detection is based on deviations between measured data and idealized model predictions. The EKD system has been incorporated into an operational engineer-oriented graphical interface, which has provided easy access to the model for both input and output of data, and for the interpretation of results. This paper describes the design considerations and technology behind the EKD system and the engineering interface. The paper also presents examples of the system running in real time at a slimhole rig site.

  3. The Formation of Social Conventions in Real-Time Environments

    PubMed Central

    Hawkins, Robert X. D.; Goldstone, Robert L.

    2016-01-01

    Why are some behaviors governed by strong social conventions while others are not? We experimentally investigate two factors contributing to the formation of conventions in a game of impure coordination: the continuity of interaction within each round of play (simultaneous vs. real-time) and the stakes of the interaction (high vs. low differences between payoffs). To maximize efficiency and fairness in this game, players must coordinate on one of two equally advantageous equilibria. In agreement with other studies manipulating continuity of interaction, we find that players who were allowed to interact continuously within rounds achieved outcomes with greater efficiency and fairness than players who were forced to make simultaneous decisions. However, the stability of equilibria in the real-time condition varied systematically and dramatically with stakes: players converged on more stable patterns of behavior when stakes are high. To account for this result, we present a novel analysis of the dynamics of continuous interaction and signaling within rounds. We discuss this previously unconsidered interaction between within-trial and across-trial dynamics as a form of social canalization. When stakes are low in a real-time environment, players can satisfactorily coordinate ‘on the fly’, but when stakes are high there is increased pressure to establish and adhere to shared expectations that persist across rounds. PMID:27002729

  4. Exploring Earthquakes in Real-Time

    NASA Astrophysics Data System (ADS)

    Bravo, T. K.; Kafka, A. L.; Coleman, B.; Taber, J. J.

    2013-12-01

    Earthquakes capture the attention of students and inspire them to explore the Earth. Adding the ability to view and explore recordings of significant and newsworthy earthquakes in real-time makes the subject even more compelling. To address this opportunity, the Incorporated Research Institutions for Seismology (IRIS), in collaboration with Moravian College, developed ';jAmaSeis', a cross-platform application that enables students to access real-time earthquake waveform data. Students can watch as the seismic waves are recorded on their computer, and can be among the first to analyze the data from an earthquake. jAmaSeis facilitates student centered investigations of seismological concepts using either a low-cost educational seismograph or streamed data from other educational seismographs or from any seismic station that sends data to the IRIS Data Management System. After an earthquake, students can analyze the seismograms to determine characteristics of earthquakes such as time of occurrence, distance from the epicenter to the station, magnitude, and location. The software has been designed to provide graphical clues to guide students in the analysis and assist in their interpretations. Since jAmaSeis can simultaneously record up to three stations from anywhere on the planet, there are numerous opportunities for student driven investigations. For example, students can explore differences in the seismograms from different distances from an earthquake and compare waveforms from different azimuthal directions. Students can simultaneously monitor seismicity at a tectonic plate boundary and in the middle of the plate regardless of their school location. This can help students discover for themselves the ideas underlying seismic wave propagation, regional earthquake hazards, magnitude-frequency relationships, and the details of plate tectonics. The real-time nature of the data keeps the investigations dynamic, and offers students countless opportunities to explore.

  5. Prototype COBRA near-real-time processor

    NASA Astrophysics Data System (ADS)

    Earp, Samuel L.; Marshall, J. W.; Anthony, E. R.

    1996-05-01

    The U.S. Marine Corps COBRA countermine surveillance program has developed, as a risk- reduction alternative, a near real-time processor for the output of the COBRA multispectral camera. This processor has been tested using approximately 13.5 hours of video data from the COBRA DT-0 developmental test, representing approximately 243,000 frames of multispectral data. The results have been very encouraging--the system is robust and the minefield detection performance has met the goals of the COBRA program. The MITRE COBRA prototype processor is built from commercial-off-the-shelf VME bus technology. Video capture is provided by a Transtech TDM 435 capture/display VME card. Control is performed on a GMSV64 Super Sparc card that resides in two VME slots. The compute engine consists of two Pentek 4270 Quad TMS320C40 digital signal processing boards. There are two additional 6U VME boards to provide fast SCSI IO. The system is capable of capturing, digitizing and processing the COBRA data stream at between one-eighth and one-half real-time, depending on processing options. The nominal compute power of the system is 2.2 GOPS, 450 MFLOPS. The system is easily upgradeable due to the open architecture--one proposed upgrade will be to increase the number of available TMS320C40 processors to sixteen, providing real-time performance without compromising the current investment in software and hardware. The software for the system is primarily written in C, with hand-optimized assembler code for portions of the compute kernel. The algorithm that is implemented is based on the MITRE minefield detection algorithm detailed at AeroSense '95. The system development required a registration algorithm--this was the only algorithm development that was performed, the rest of the algorithms coming from previous MITRE effort on the COBRA program. Lessons learned from the development and upgrade/test plans will be presented.

  6. Real-time structured light depth extraction

    NASA Astrophysics Data System (ADS)

    Keller, Kurtis; Ackerman, Jeremy D.

    2000-03-01

    Gathering depth data using structured light has been a procedure for many different environments and uses. Many of these system are utilized instead of laser line scanning because of their quickness. However, to utilize depth extraction for some applications, in our case laparoscopic surgery, the depth extraction must be in real time. We have developed an apparatus that speeds up the raw image display and grabbing in structured light depth extraction from 30 frames per second to 60 and 180 frames per second. This results in an updated depth and texture map of about 15 times per second versus about 3. This increased update rate allows for real time depth extraction for use in augmented medical/surgical applications. Our miniature, fist-sized projector utilizes an internal ferro-reflective LCD display that is illuminated with cold light from a flex light pipe. The miniature projector, attachable to a laparoscope, displays inverted pairs of structured light into the body where these images are then viewed by a high-speed camera set slightly off axis from the projector that grabs images synchronously. The images from the camera are ported to a graphics-processing card where six frames are worked on simultaneously to extract depth and create mapped textures from these images. This information is then sent to the host computer with 3D coordinate information of the projector/camera and the associated textures. The surgeon is then able to view body images in real time from different locations without physically moving the laparoscope imager/projector, thereby, reducing the trauma of moving laparoscopes in the patient.

  7. Real-time failure control (SAFD)

    NASA Technical Reports Server (NTRS)

    Panossian, Hagop V.; Kemp, Victoria R.; Eckerling, Sherry J.

    1990-01-01

    The Real Time Failure Control program involves development of a failure detection algorithm, referred as System for Failure and Anomaly Detection (SAFD), for the Space Shuttle Main Engine (SSME). This failure detection approach is signal-based and it entails monitoring SSME measurement signals based on predetermined and computed mean values and standard deviations. Twenty four engine measurements are included in the algorithm and provisions are made to add more parameters if needed. Six major sections of research are presented: (1) SAFD algorithm development; (2) SAFD simulations; (3) Digital Transient Model failure simulation; (4) closed-loop simulation; (5) SAFD current limitations; and (6) enhancements planned for.

  8. Open Source Real Time Operating Systems Overview

    SciTech Connect

    Straumann, Till

    2001-12-11

    Modern control systems applications are often built on top of a real time operating system (RTOS) which provides the necessary hardware abstraction as well as scheduling, networking and other services. Several open source RTOS solutions are publicly available, which is very attractive, both from an economic (no licensing fees) as well as from a technical (control over the source code) point of view. This contribution gives an overview of the RTLinux and RTEMS systems (architecture, development environment, API etc.). Both systems feature most popular CPUs, several APIs (including Posix), networking, portability and optional commercial support. Some performance figures are presented, focusing on interrupt latency and context switching delay.

  9. Systems Analyze Water Quality in Real Time

    NASA Technical Reports Server (NTRS)

    2010-01-01

    A water analyzer developed under Small Business Innovation Research (SBIR) contracts with Kennedy Space Center now monitors treatment processes at water and wastewater facilities around the world. Originally designed to provide real-time detection of nutrient levels in hydroponic solutions for growing plants in space, the ChemScan analyzer, produced by ASA Analytics Inc., of Waukesha, Wisconsin, utilizes spectrometry and chemometric algorithms to automatically analyze multiple parameters in the water treatment process with little need for maintenance, calibration, or operator intervention. The company has experienced a compound annual growth rate of 40 percent over its 15-year history as a direct result of the technology's success.

  10. Real-time teleteaching in medical physics.

    PubMed

    Woo, M; Ng, Kh

    2008-01-01

    Medical physics is a relatively small professional community, usually with a scarcity of expertise that could greatly benefit students entering the field. However, the reach of the profession can span great geographical distances, making the training of students a difficult task. In addition to the requirement of training new students, the evolving field of medical physics, with its many emerging advanced techniques and technologies, could benefit greatly from ongoing continuing education as well as consultation with experts.Many continuing education courses and workshops are constantly being offered, including many web-based study courses and virtual libraries. However, one mode of education and communication that has not been widely used is the real-time interactive process. Video-based conferencing systems do exist, but these usually require a substantial amount of effort and cost to set up.The authors have been working on promoting the ever-expanding capability of the Internet to facilitate the education of medical physics to students entering the field. A pilot project has been carried out for six years and reported previously. The project is a collaboration between the Department of Medical Physics at the Toronto Odette Cancer Centre in Canada and the Department of Biomedical Imaging at the University of Malaya in Malaysia. Since 2001, medical physics graduate students at the University of Malaya have been taught by lecturers from Toronto every year, using the Internet as the main tool of communication.The pilot study explored the different methods that can be used to provide real-time interactive remote education, and delivered traditional classroom lectures as well as hands-on workshops.Another similar project was started in 2007 to offer real-time teaching to a class of medical physics students at Wuhan University in Hubei, China. There are new challenges as well as new opportunities associated with this project. By building an inventory of tools and

  11. General purpose computers in real time

    SciTech Connect

    Biel, J.R.

    1989-09-18

    I see three main trends in the use of general purpose computers in real time. The first is more processing power. The second is the use of higher speed interconnects between computers (allowing more data to be delivered to the processors). The third is the use of larger programs running in the computers. Although there is still work that needs to be done, I believe that all indications are that the online need for general purpose computers should be available for the SCC and LHC machines. 2 figs.

  12. Real-Time Reed-Solomon Decoder

    NASA Technical Reports Server (NTRS)

    Maki, Gary K.; Cameron, Kelly B.; Owsley, Patrick A.

    1994-01-01

    Generic Reed-Solomon decoder fast enough to correct errors in real time in practical applications designed to be implemented in fewer and smaller very-large-scale integrated, VLSI, circuit chips. Configured to operate in pipelined manner. One outstanding aspect of decoder design is that Euclid multiplier and divider modules contain Galoisfield multipliers configured as combinational-logic cells. Operates at speeds greater than older multipliers. Cellular configuration highly regular and requires little interconnection area, making it ideal for implementation in extraordinarily dense VLSI circuitry. Flight electronics single chip version of this technology implemented and available.

  13. Object detection in real-time

    NASA Astrophysics Data System (ADS)

    Solder, Ulrich; Graefe, Volker

    1991-03-01

    An algorithm working on monocular gray-scale image sequences for object detection combined with a road tracker is presented. This algorithm appropriate for the real-time demands of an autonomous car driving with speeds over 40 km/h may be used for triggering obstacle avoidance maneuvers such as coming to a safe stop automatically in front of an obstacle or following another car. Moving and static objects have been detected in real-world experiments on various types of roads even under unfavorable weather conditions. . Morgenthaler and

  14. [Development of real-time CT fluoroscopy].

    PubMed

    Katada, K; Anno, H; Takeshita, G; Ogura, Y; Koga, S; Ida, Y; Nonomura, K; Kanno, T; Ohashi, A; Sata, S

    1994-10-25

    A new CT system that permits real-time monitoring of CT images was developed. Phantom and volunteer studies revealed that the images were displayed at a rate of six per second with a delay time of 0.83 second with clinically sufficient resolution (256 x 256) using the newly developed fast image processor and partial-reconstruction algorithm. The clinical trial of stereotactic aspiration of intracerebral hematoma was successful. The initial trial with CT fluoroscopy revealed potential usefulness of the system in biopsy and other CT-guided interventions. PMID:9261196

  15. Near real time data processing system

    NASA Astrophysics Data System (ADS)

    Mousessian, Ardvas; Vuu, Christina

    2008-08-01

    Raytheon recently developed and implemented a Near Real Time (NRT) data processing subsystem for Earth Observing System (EOS) Microwave Limb Sounder (MLS3) instrument on NASA Aura spacecraft. The NRT can be viewed as a customized Science Information Processing System (SIPS) where the measurements and information provided by the instrument are expeditiously processed, packaged, and delivered. The purpose of the MLS NRT is to process Level 0 data up through Level 2, and distribute standard data products to the customer within 3-5 hours of the first set of data arrival.

  16. Real time analysis of voiced sounds

    NASA Technical Reports Server (NTRS)

    Hong, J. P. (Inventor)

    1976-01-01

    A power spectrum analysis of the harmonic content of a voiced sound signal is conducted in real time by phase-lock-loop tracking of the fundamental frequency, (f sub 0) of the signal and successive harmonics (h sub 1 through h sub n) of the fundamental frequency. The analysis also includes measuring the quadrature power and phase of each frequency tracked, differentiating the power measurements of the harmonics in adjacent pairs, and analyzing successive differentials to determine peak power points in the power spectrum for display or use in analysis of voiced sound, such as for voice recognition.

  17. Real-Time Optical Monitoring of GRBs

    NASA Astrophysics Data System (ADS)

    Hudec, René; Křížek, Miroslav

    2006-05-01

    Even the fastest alert robotic follow-up telescope is unable to cover the times just after (within first 10 seconds) and before GRB triggers. This time domain is accessible by optical monitors only. We report on analyses of GRB positions on images taken by optical photographic monitors (now operated remotely) within the European meteor network EN. This system is able to provide real-time and pre-burst optical data for GRBs with limiting magnitudes up to 12 in the best cases. The image database is searchable by special software for coincidences with GRBs and the particular images are then scanned and evaluated by computer.

  18. Comparison of Four Different Supraglottic Airway Devices in Terms of Efficacy, Intra-ocular Pressure and Haemodynamic Parameters in Children Undergoing Ophthalmic Surgery

    PubMed Central

    Peker, Gökhan; Takmaz, Suna Akın; Baltacı, Bülent; Başar, Hülya; Kotanoğlu, Mustafa

    2015-01-01

    Objective The aim of this study was to compare insertion parameters of four different types of supraglottic airway devices (SGAD) (Classic LMA, I-gel LMA, Proseal LMA, Cobra PLA) in children undergoing ophthalmic surgery and to determine the effect on intra-ocular pressure (IOP) and haemodynamic responses during insertion. Methods Sixty American society of Anesthesiologists (ASA) I–II children aged 1–10 years undergoing extra-ocular ophthalmic surgery were randomly divided into four groups (Group LMA, Group I-gel LMA, Group PLMA and Group CPLA) in this prospective, randomised study. Anaesthesia was induced with decreasing sevoflurane concentrations (8%–2%) in a mixture of 50% N2O-O2. All SGADs were inserted under deep anaesthesia. The characteristics of insertion (number of attempts, ease and time), oropharyngeal leak pressure (OLP) and complications were recorded. IOP in both eyes, heart rate (HR), mean arterial pressure (MAP) and EtCO2 were measured before and 2 and 5 min after insertion of the SGADs. Results There was no difference between the groups in terms of the characteristics of insertion. The mean IOP did not increase significantly in all groups. MAP and HR changes were similar among the groups during follow-up. In all groups, HR increased 2 min after insertion (statistically insignificant) and returned to the baseline value 5 min after insertion. A statistically significant correlation was seen between HR increase and IOP values before and after insertion of the SGADs (p=0.006, correlation coefficient=0.352). Desaturation was seen in one patient in Groups LMA, PLMA and CPLA, and laryngospasm was seen in two patients in Group CPLA and in one patient in Group LMA. Conclusion It was seen that during insertion of Classic LMA, I-gel LMA, Proseal LMA and Cobra PLA, IOP did not increase and haemodynamic stability was maintained in children undergoing extra-ocular ophthalmic surgery. PMID:27366519

  19. Short-Term Intraocular Pressure Elevations after Combined Phacoemulsification and Implantation of Two Trabecular Micro-Bypass Stents: Prednisolone versus Loteprednol

    PubMed Central

    Wang, Qianqian; Harasymowycz, Paul

    2015-01-01

    Objective. To compare the effects of prednisolone and of loteprednol after combined phacoemulsification and trabecular micro-bypass stent implantation (phaco-iStent). Methods. Patients who underwent phaco-iStent between April 2013 and November 2014 were identified by retrospective chart review. Postoperatively, they received either prednisolone (n = 38) or loteprednol (n = 58). Baseline data was compared. Primary outcomes including intraocular pressure (IOP) and number of glaucoma medications (NGM) were analyzed at preoperative visit, postoperative day 1, weeks 1-2, weeks 3-4, and months 2-3. Results. Both groups had similar preoperative parameters (p > 0.05). The mean IOP spike occurred at postoperative weeks 1-2 with an increase of 2.21 ± 7.30 mmHg in the loteprednol group and 2.54 ± 9.28 mmHg in the prednisolone group. It decreased by weeks 3-4 in both groups and continued to improve at months 2-3. NGM showed significant reduction (p < 0.0001) after the surgery and remained stable in both groups. No significant group effect or time-group interaction in IOP and NGM evolution was detected (p > 0.05). The proportions of patients needing paracentesis were similar between the two groups. Conclusion. Similar early IOP elevations after combined phaco-iStent occurred with both prednisolone and loteprednol. Facilitated glucocorticoid infusion, altered aqueous humor outflow, and local inflammation may be contributing factors. PMID:26266045

  20. Comparison of Intraocular Pressure before and after Laser In Situ Keratomileusis Refractive Surgery Measured with Perkins Tonometry, Noncontact Tonometry, and Transpalpebral Tonometry

    PubMed Central

    Cacho, Isabel; Sanchez-Naves, Juan; Batres, Laura; Pintor, Jesús; Carracedo, Gonzalo

    2015-01-01

    Purpose. To compare the intraocular pressure (IOP) before and after Laser In Situ Keratomileusis (LASIK), measured by Diaton, Perkins, and noncontact air pulse tonometers. Methods. Fifty-seven patients with a mean age of 34.88 were scheduled for myopia LASIK treatment. Spherical equivalent refraction (SER), corneal curvature (K), and central corneal thickness (CCT) and superior corneal thickness (SCT) were obtained before and after LASIK surgery. IOP values before and after surgery were measured using Diaton, Perkins, and noncontact air pulse tonometers. Results. The IOP values before and after LASIK surgery using Perkins tonometer and air tonometers were statistically significant (p < 0.05). However, no significant differences were found (p > 0.05) for IOP values measured with Diaton tonometer. CCT decreases significantly after surgery (p < 0.05) but no statistical differences were found in SCT (p = 0.08). Correlations between pre- and postsurgery were found for all tonometers used, with p = 0.001 and r = 0.434 for the air pulse tonometer, p = 0.008 and r = 0.355 for Perkins, and p < 0.001 and r = 0.637 for Diaton. Conclusion. Transpalpebral tonometry may be useful for measuring postsurgery IOP after myopic LASIK ablation because this technique is not influenced by the treatment. PMID:26167293

  1. Effect of preservative removal from fixed-combination bimatoprost/timolol on intraocular pressure lowering: a potential timolol dose–response phenomenon

    PubMed Central

    Shen, Jie; Bejanian, Marina

    2016-01-01

    Purpose Many patients with glaucoma require combination therapies to achieve target intraocular pressure (IOP) and preserve visual function. Ocular hypotensives often contain a preservative (eg, benzalkonium chloride [BAK]), but preservative-free (PF) formulations have been developed for patients with sensitivity. A Phase III study found the efficacy of bimatoprost 0.03%/timolol 0.5% (bim/tim, Ganfort®) PF to be equivalent to that of preserved bim/tim, although a trend favoring bim/tim PF was observed. As BAK is a corneal penetration enhancer, this literature review aims to explain these findings by exploring the relationship between timolol concentration and its IOP-lowering effect. Methods Systematic searches were performed in Scopus and PubMed for clinical trials published in English between 1960 and July 2014 using the keywords “timolol”, “intraocular pressure”, and the concentrations “1%, 0.5%, OR 0.25%”. Articles that directly compared IOP-lowering effects of ≥2 concentrations of timolol were identified by manual screening, and cross-checked for duplication. Results Seventeen studies that included 10–371 patients were evaluated; the majority were randomized (16/17), double-masked (14/17), and enrolled patients with open-angle glaucoma or ocular hypertension (12/17). All studies investigated timolol in preserved formulations. Timolol concentrations tested ranged from 0.008% to 1.5%. Of 13 studies comparing timolol 0.25% versus 0.5%, two found the 0.25% dose to have greater IOP-lowering effects, and three reported the opposite; eight reported similar IOP lowering. Results also indicate that timolol 0.5% may be more effective than higher concentrations. Conclusion The evidence suggests that timolol may have an inverted U-shaped dose–response curve, and that its optimal IOP-lowering concentration is between 0.25% and 0.5%. Compared with bim/tim, removal of the permeability enhancer BAK in bim/tim PF could have resulted in a lower timolol

  2. Real-time virtual room acoustic simulation

    NASA Astrophysics Data System (ADS)

    Carneal, James P.; Johnson, Jan; Johnson, Troge; Johnson, Marty

    2003-10-01

    A realistic virtual room acoustic simulation has been implemented on a PC-based computer in near real-time. Room acoustics are calculated by the image source method using realistic absorption coefficients for a variety of realistic surfaces and programmed in MATLAB. The resulting impulse response filters are then applied in near real-time using fast convolution DSP techniques using data being read from a CD-ROM. The system was implemented in a virtual acoustic room facility. Optimizations have been performed to retain the realistic virtual room effect while minimizing computations through limited psycho-acoustic testing. In general, realistic anechoic to reverberant virtual rooms have been re-created with six 8192 coefficient filters. To provide realistic simulations, special care must be taken to accurately reproduce the low frequency acoustics. Since the virtual room acoustic facility was not totally anechoic (as are most anechoic chambers), inverse filters were applied to compensate for over-amplified acoustics at frequencies below 350 Hz.

  3. Real-time applications of neural nets

    SciTech Connect

    Spencer, J.E.

    1989-05-01

    Producing, accelerating and colliding very high power, low emittance beams for long periods is a formidable problem in real-time control. As energy has grown exponentially in time so has the complexity of the machines and their control systems. Similar growth rates have occurred in many areas, e.g., improved integrated circuits have been paid for with comparable increases in complexity. However, in this case, reliability, capability and cost have improved due to reduced size, high production and increased integration which allow various kinds of feedback. In contrast, most large complex systems (LCS) are perceived to lack such possibilities because only one copy is made. Neural nets, as a metaphor for LCS, suggest ways to circumvent such limitations. It is argued that they are logically equivalent to multi-loop feedback/forward control of faulty systems. While complimentary to AI, they mesh nicely with characteristics desired for real-time systems. Such issues are considered, examples given and possibilities discussed. 21 refs., 6 figs.

  4. Residential Real-time Price Response Simulation

    SciTech Connect

    Widergren, Steven E.; Subbarao, Krishnappa; Chassin, David P.; Fuller, Jason C.; Pratt, Robert G.

    2011-10-10

    The electric industry is gaining experience with innovative price responsive demand pilots and limited roll-outs to customers. One of these pilots is investigating real-time pricing signals to engage end-use systems and local distributed generation and storage in a distributed optimization process. Attractive aspects about the approach include strong scalability characteristics, simplified interfaces between automation devices, and the adaptability to integrate a wide variety of devices and systems. Experience in this nascent field is revealing a rich array of for engineering decisions and the application of complexity theory. To test the decisions, computer simulations are used to reveal insights about design, demand elasticity, and the limits of response (including consumer fatigue). Agent-based approaches lend themselves well in the simulation to modeling the participation and interaction of each piece of equipment on a distribution feeder. This paper discusses rate design and simulation experiences at the distribution feeder level where consumers and their HVAC systems and water heaters on a feeder receive real-time pricing signals.

  5. Real-time adaptive video image enhancement

    NASA Astrophysics Data System (ADS)

    Garside, John R.; Harrison, Chris G.

    1999-07-01

    As part of a continuing collaboration between the University of Manchester and British Aerospace, a signal processing array has been constructed to demonstrate that it is feasible to compensate a video signal for the degradation caused by atmospheric haze in real-time. Previously reported work has shown good agreement between a simple physical model of light scattering by atmospheric haze and the observed loss of contrast. This model predicts a characteristic relationship between contrast loss in the image and the range from the camera to the scene. For an airborne camera, the slant-range to a point on the ground may be estimated from the airplane's pose, as reported by the inertial navigation system, and the contrast may be obtained from the camera's output. Fusing data from these two streams provides a means of estimating model parameters such as the visibility and the overall illumination of the scene. This knowledge allows the same model to be applied in reverse, thus restoring the contrast lost to atmospheric haze. An efficient approximation of range is vital for a real-time implementation of the method. Preliminary results show that an adaptive approach to fitting the model's parameters, exploiting the temporal correlation between video frames, leads to a robust implementation with a significantly accelerated throughput.

  6. Real-Time Flight Envelope Monitoring System

    NASA Technical Reports Server (NTRS)

    Kerho, Michael; Bragg, Michael B.; Ansell, Phillip J.

    2012-01-01

    The objective of this effort was to show that real-time aircraft control-surface hinge-moment information could be used to provide a robust and reliable prediction of vehicle performance and control authority degradation. For a given airfoil section with a control surface -- be it a wing with an aileron, rudder, or elevator -- the control-surface hinge moment is sensitive to the aerodynamic characteristics of the section. As a result, changes in the aerodynamics of the section due to angle-of-attack or environmental effects such as icing, heavy rain, surface contaminants, bird strikes, or battle damage will affect the control surface hinge moment. These changes include both the magnitude of the hinge moment and its sign in a time-averaged sense, and the variation of the hinge moment with time. The current program attempts to take the real-time hinge moment information from the aircraft control surfaces and develop a system to predict aircraft envelope boundaries across a range of conditions, alerting the flight crew to reductions in aircraft controllability and flight boundaries.

  7. Real Time Simulation of Power Grid Disruptions

    SciTech Connect

    Chinthavali, Supriya; Dimitrovski, Aleksandar D; Fernandez, Steven J; Groer, Christopher S; Nutaro, James J; Olama, Mohammed M; Omitaomu, Olufemi A; Shankar, Mallikarjun; Spafford, Kyle L; Vacaliuc, Bogdan

    2012-11-01

    DOE-OE and DOE-SC workshops (Reference 1-3) identified the key power grid problem that requires insight addressable by the next generation of exascale computing is coupling of real-time data streams (1-2 TB per hour) as the streams are ingested to dynamic models. These models would then identify predicted disruptions in time (2-4 seconds) to trigger the smart grid s self healing functions. This project attempted to establish the feasibility of this approach and defined the scientific issues, and demonstrated example solutions to important smart grid simulation problems. These objectives were accomplished by 1) using the existing frequency recorders on the national grid to establish a representative and scalable real-time data stream; 2) invoking ORNL signature identification algorithms; 3) modeling dynamically a representative region of the Eastern interconnect using an institutional cluster, measuring the scalability and computational benchmarks for a national capability; and 4) constructing a prototype simulation for the system s concept of smart grid deployment. The delivered ORNL enduring capability included: 1) data processing and simulation metrics to design a national capability justifying exascale applications; 2) Software and intellectual property built around the example solutions; 3) demonstrated dynamic models to design few second self-healing.

  8. Neutron monitor database in real time

    NASA Astrophysics Data System (ADS)

    Kozlov, Valery; Kudela, Karel; Starodubtsev, Sergei; Turpanov, Alexey; Usoskin, Ilya; Yanke, Victor

    2003-09-01

    A first distributed Real Time Cosmic Ray Database using measurements of several neutron monitors is presented. The aim of the project is to develop a unified database with data from different neutron monitors collected together, in unified format and to provide a user with several commonly used data access methods. The database contains original cosmic ray as well as all housekeeping and technical data necessary for scientific data analysis. Currently the database includes Lomnicky Stit, Moscow, Oulu, Tixie Bay, Yakutsk stations and it is opened for other neutron monitors. The main database server is located in IKFIA SB RAS (Yakutsk) but there will be several mirrors of the database. The datbase and all its mirrors are updated on the nearly real-time (1 hour) basis. The data access software includes WWW-interface, Perl scipts and C library, which may be linked to a user program. Most of frequently used functions are implemented to make it operable to users without SQL language knowledge. A draft of the data representation standard is suggested, based on common practice of neutron monitor community. The database engine is freely distributed open-sourced PostgreSQL server coupled with a set of replication tools developed at Bioengineering division of the IRCCS E. Medea, Italy.

  9. Near-real-time Jason-1 Images

    NASA Astrophysics Data System (ADS)

    Rigor, E. M.; Bingham, A.; Case, K.

    2002-12-01

    The Jason-1 satellite mission provides sea surface height measurements in near-real-time (NRT). These operational data can be used for a variety of scientific and commercial applications, including marine meteorology, ship routing, and climate prediction. The Physical Oceanography Distributed Active Archive Center (PO.DAAC), NASA's primary data center for archiving and distributing oceanographic data, is supporting the JASON-1 mission by capturing NRT data from Jason Ground System (JGS) and distributing the data to operational users. In addition, PO.DAAC will be processing the data to create value-added NRT browse images, which will be made available, along with their associated binary data, through the Near-Real-Time Image Distribution Server (NEREIDS). Two NRT data products will be processed by JGS and captured by PO.DAAC: Operational Sensor Data Records (OSDRs) and Interim Geophysical Data Records (IGDRs). OSDRs have a latency of three hours from data collection and an orbit accuracy of 30 cm; IGDRs are available seventy-two hours after collection and have an accuracy of 2.5 cm. After capturing these data, PO.DAAC will automatically create significant wave height, wind speed, and water vapor content browse images from the OSDR data. Additional parameters will be provided from the IGDR data product, such as the sea surface height anomaly, among others. In this poster, we describe the functionality of NEREIDS and demonstrate the usefulness of operational altimetric data for scientific applications.

  10. Real-time design with peer tasks

    NASA Technical Reports Server (NTRS)

    Goforth, Andre; Howes, Norman R.; Wood, Jonathan D.; Barnes, Michael J.

    1995-01-01

    We introduce a real-time design methodology for large scale, distributed, parallel architecture, real-time systems (LDPARTS), as an alternative to those methods using rate or dead-line monotonic analysis. In our method the fundamental units of prioritization, work items, are domain specific objects with timing requirements (deadlines) found in user's specification. A work item consists of a collection of tasks of equal priority. Current scheduling theories are applied with artifact deadlines introduced by the designer whereas our method schedules work items to meet user's specification deadlines (sometimes called end-to-end deadlines). Our method supports these scheduling properties. Work item scheduling is based on domain specific importance instead of task level urgency and still meets as many user specification deadlines as can be met by scheduling tasks with respect to urgency. Second, the minimum (closest) on-line deadline that can be guaranteed for a work item of highest importance, scheduled at run time, is approximately the inverse of the throughput, measured in work items per second. Third, throughput is not degraded during overload and instead of resorting to task shedding during overload, the designer can specify which work items to shed. We prove these properties in a mathematical model.

  11. 3D MR imaging in real time

    NASA Astrophysics Data System (ADS)

    Guttman, Michael A.; McVeigh, Elliot R.

    2001-05-01

    A system has been developed to produce live 3D volume renderings from an MR scanner. Whereas real-time 2D MR imaging has been demonstrated by several groups, 3D volumes are currently rendered off-line to gain greater understanding of anatomical structures. For example, surgical planning is sometimes performed by viewing 2D images or 3D renderings from previously acquired image data. A disadvantage of this approach is misregistration which could occur if the anatomy changes due to normal muscle contractions or surgical manipulation. The ability to produce volume renderings in real-time and present them in the magnet room could eliminate this problem, and enable or benefit other types of interventional procedures. The system uses the data stream generated by a fast 2D multi- slice pulse sequence to update a volume rendering immediately after a new slice is available. We demonstrate some basic types of user interaction with the rendering during imaging at a rate of up to 20 frames per second.

  12. Real-Time and Near Real-Time Data for Space Weather Applications and Services

    NASA Astrophysics Data System (ADS)

    Singer, H. J.; Balch, C. C.; Biesecker, D. A.; Matsuo, T.; Onsager, T. G.

    2015-12-01

    Space weather can be defined as conditions in the vicinity of Earth and in the interplanetary environment that are caused primarily by solar processes and influenced by conditions on Earth and its atmosphere. Examples of space weather are the conditions that result from geomagnetic storms, solar particle events, and bursts of intense solar flare radiation. These conditions can have impacts on modern-day technologies such as GPS or electric power grids and on human activities such as astronauts living on the International Space Station or explorers traveling to the moon or Mars. While the ultimate space weather goal is accurate prediction of future space weather conditions, for many applications and services, we rely on real-time and near-real time observations and model results for the specification of current conditions. In this presentation, we will describe the space weather system and the need for real-time and near-real time data that drive the system, characterize conditions in the space environment, and are used by models for assimilation and validation. Currently available data will be assessed and a vision for future needs will be given. The challenges for establishing real-time data requirements, as well as acquiring, processing, and disseminating the data will be described, including national and international collaborations. In addition to describing how the data are used for official government products, we will also give examples of how these data are used by both the public and private sector for new applications that serve the public.

  13. Real-time, face recognition technology

    SciTech Connect

    Brady, S.

    1995-11-01

    The Institute for Scientific Computing Research (ISCR) at Lawrence Livermore National Laboratory recently developed the real-time, face recognition technology KEN. KEN uses novel imaging devices such as silicon retinas developed at Caltech or off-the-shelf CCD cameras to acquire images of a face and to compare them to a database of known faces in a robust fashion. The KEN-Online project makes that recognition technology accessible through the World Wide Web (WWW), an internet service that has recently seen explosive growth. A WWW client can submit face images, add them to the database of known faces and submit other pictures that the system tries to recognize. KEN-Online serves to evaluate the recognition technology and grow a large face database. KEN-Online includes the use of public domain tools such as mSQL for its name-database and perl scripts to assist the uploading of images.

  14. Wi-Fi real time location systems

    NASA Astrophysics Data System (ADS)

    Doll, Benjamin A.

    This thesis objective was to determine the viability of utilizing an untrained Wi-Fi. real time location system as a GPS alternative for indoor environments. Background. research showed that GPS is rarely able to penetrate buildings to provide reliable. location data. The benefit of having location information in a facility and how they might. be used for disaster or emergency relief personnel and their resources motivated this. research. A building was selected with a well-deployed Wi-Fi infrastructure and its. untrained location feature was used to determine the distance between the specified. test points and the system identified location. It was found that the average distance. from the test point throughout the facility was 14.3 feet 80% of the time. This fell within. the defined viable range and supported that an untrained Wi-Fi RTLS system could be a. viable solution for GPS's lack of availability indoors.

  15. Real time software tools and methodologies

    NASA Technical Reports Server (NTRS)

    Christofferson, M. J.

    1981-01-01

    Real time systems are characterized by high speed processing and throughput as well as asynchronous event processing requirements. These requirements give rise to particular implementations of parallel or pipeline multitasking structures, of intertask or interprocess communications mechanisms, and finally of message (buffer) routing or switching mechanisms. These mechanisms or structures, along with the data structue, describe the essential character of the system. These common structural elements and mechanisms are identified, their implementation in the form of routines, tasks or macros - in other words, tools are formalized. The tools developed support or make available the following: reentrant task creation, generalized message routing techniques, generalized task structures/task families, standardized intertask communications mechanisms, and pipeline and parallel processing architectures in a multitasking environment. Tools development raise some interesting prospects in the areas of software instrumentation and software portability. These issues are discussed following the description of the tools themselves.

  16. Near real-time traffic routing

    NASA Technical Reports Server (NTRS)

    Yang, Chaowei (Inventor); Cao, Ying (Inventor); Xie, Jibo (Inventor); Zhou, Bin (Inventor)

    2012-01-01

    A near real-time physical transportation network routing system comprising: a traffic simulation computing grid and a dynamic traffic routing service computing grid. The traffic simulator produces traffic network travel time predictions for a physical transportation network using a traffic simulation model and common input data. The physical transportation network is divided into a multiple sections. Each section has a primary zone and a buffer zone. The traffic simulation computing grid includes multiple of traffic simulation computing nodes. The common input data includes static network characteristics, an origin-destination data table, dynamic traffic information data and historical traffic data. The dynamic traffic routing service computing grid includes multiple dynamic traffic routing computing nodes and generates traffic route(s) using the traffic network travel time predictions.

  17. Real time speech formant analyzer and display

    DOEpatents

    Holland, G.E.; Struve, W.S.; Homer, J.F.

    1987-02-03

    A speech analyzer for interpretation of sound includes a sound input which converts the sound into a signal representing the sound. The signal is passed through a plurality of frequency pass filters to derive a plurality of frequency formants. These formants are converted to voltage signals by frequency-to-voltage converters and then are prepared for visual display in continuous real time. Parameters from the inputted sound are also derived and displayed. The display may then be interpreted by the user. The preferred embodiment includes a microprocessor which is interfaced with a television set for displaying of the sound formants. The microprocessor software enables the sound analyzer to present a variety of display modes for interpretive and therapeutic used by the user. 19 figs.

  18. Real time speech formant analyzer and display

    DOEpatents

    Holland, George E.; Struve, Walter S.; Homer, John F.

    1987-01-01

    A speech analyzer for interpretation of sound includes a sound input which converts the sound into a signal representing the sound. The signal is passed through a plurality of frequency pass filters to derive a plurality of frequency formants. These formants are converted to voltage signals by frequency-to-voltage converters and then are prepared for visual display in continuous real time. Parameters from the inputted sound are also derived and displayed. The display may then be interpreted by the user. The preferred embodiment includes a microprocessor which is interfaced with a television set for displaying of the sound formants. The microprocessor software enables the sound analyzer to present a variety of display modes for interpretive and therapeutic used by the user.

  19. In-line real time air monitor

    DOEpatents

    Wise, M.B.; Thompson, C.V.

    1998-07-14

    An in-line gas monitor capable of accurate gas composition analysis in a continuous real time manner even under strong applied vacuum conditions operates by mixing an air sample with helium forming a sample gas in two complementary sample loops embedded in a manifold which includes two pairs of 3-way solenoid valves. The sample gas is then analyzed in an ion trap mass spectrometer on a continuous basis. Two valve drivers actuate the two pairs of 3-way valves in a reciprocating fashion, so that there is always flow through the in-line gas monitor via one or the other of the sample loops. The duty cycle for the two pairs of 3-way valves is varied by tuning the two valve drivers to a duty cycle typically between 0.2 to 0.7 seconds. 3 figs.

  20. In-line real time air monitor

    DOEpatents

    Wise, Marcus B.; Thompson, Cyril V.

    1998-01-01

    An in-line gas monitor capable of accurate gas composition analysis in a continuous real time manner even under strong applied vacuum conditions operates by mixing an air sample with helium forming a sample gas in two complementary sample loops embedded in a manifold which includes two pairs of 3-way solenoid valves. The sample gas is then analyzed in an ion trap mass spectrometer on a continuous basis. Two valve drivers actuate the two pairs of 3-way valves in a reciprocating fashion, so that there is always flow through the in-line gas monitor via one or the other of the sample loops. The duty cycle for the two pairs of 3-way valves is varied by tuning the two valve drivers to a duty cycle typically between 0.2 to 0.7 seconds.

  1. Filming protein fibrillogenesis in real time

    NASA Astrophysics Data System (ADS)

    Bella, Angelo; Shaw, Michael; Ray, Santanu; Ryadnov, Maxim G.

    2014-12-01

    Protein fibrillogenesis is a universal tool of nano-to-micro scale construction supporting different forms of biological function. Its exploitable potential in nanoscience and technology is substantial, but the direct observation of homogeneous fibre growth able to underpin a kinetic-based rationale for building customized nanostructures in situ is lacking. Here we introduce a kinetic model of de novo protein fibrillogenesis which we imaged at the nanoscale and in real time, filmed. The model helped to reveal that, in contrast to heterogeneous amyloid assemblies, homogeneous protein recruitment is principally characterized by uniform rates of cooperative growth at both ends of growing fibers, bi-directional growth, with lateral growth arrested at a post-seeding stage. The model provides a foundation for in situ engineering of sequence-prescribed fibrous architectures.

  2. PCs stir reliability, real-time concerns

    SciTech Connect

    Strothman, J.

    1994-11-01

    While pre-Christmas price wars regularly boost personal computer sales this time of year, price cuts alone won`t cause process control systems designers to open their wallets and buy PCs. User studies and user feedback to process control equipment suppliers show several other issues continue to rank higher than price including: (1) Hardware and software reliability; (2) easy-to-use user interfaces; (3) ability to do multitasking; (4) need for real-time updates. These and several other non-price issues - including open versus proprietary systems, slower scan rates from PCs compared to programmable controllers, and assurances that the PC will work in an industrial environment - scored high in a study authored earlier this year by Jesse Yoder, owner of Idea Network, Clinton, NJ. The report, titled {open_quotes}The World Market for Process Control Equipment,{close_quotes} was written for FIND/SVP, a New York City market research firm.

  3. A Flexible Real-Time Architecture

    SciTech Connect

    WICKSTROM,GREGORY L.

    2000-08-17

    Assuring hard real-time characteristics of I/O associated with embedded software is often a difficult task. Input-Output related statements are often intermixed with the computational code, resulting in I/O timing that is dependent on the execution path and computational load. One way to mitigate this problem is through the use of interrupts. However, the non-determinism that is introduced by interrupt driven I/O may be so difficult to analyze that it is prohibited in some high consequence systems. This paper describes a balanced hardware/software solution to obtain consistent interrupt-free I/O timing, and results in software that is much more amenable to analysis.

  4. Terrestrial Real-Time Volcano Monitoring

    NASA Astrophysics Data System (ADS)

    Franke, M.

    2013-12-01

    As volcano monitoring involves more and different sensors from seismic to GPS receivers, from video and thermal cameras to multi-parameter probes measuring temperature, ph values and humidity in the ground and the air, it becomes important to design real-time networks that integrate and leverage the multitude of available parameters. In order to do so some simple principles need to be observed: a) a common time base for all measurements, b) a packetized general data communication protocol for acquisition and distribution, c) an open and well documented interface to the data permitting standard and emerging innovative processing, and d) an intuitive visualization platform for scientists and civil defense personnel. Although mentioned as simple principles, the list above does not necessarily lead to obvious solutions or integrated systems, which is, however, required to take advantage of the available data. Only once the different data streams are put into context to each other in terms of time and location can a broader view be obtained and additional information extracted. The presentation is a summary of currently available technologies and how they can achieve the goal of an integrated real-time volcano monitoring system. A common time base are standard for seismic and GPS networks. In different projects we extended this to video feeds and time-lapse photography. Other probes have been integrated with vault interface enclosures (VIE) as used in the Transportable Array (TA) of the USArray. The VIE can accommodate the sensors employed in volcano monitoring. The TA has shown that Antelope is a versatile and robust middleware. It provides the required packetized general communication protocol that is independent from the actual physical communication link leaving the network design to adopt appropriate and possible hybrid solutions. This applies for the data acquisition and the data/information dissemination providing both a much needed collaboration platform, as

  5. Real-time slicing of data space

    SciTech Connect

    Crawfis, R.A.

    1996-07-01

    Real-time rendering of iso-contour surfaces is problematic for large complex data sets. In this paper, an algorithm is presented that allows very rapid representation of an interval set surrounding a iso-contour surface. The algorithm draws upon three main ideas. A fast indexing scheme is used to select only those data points near the contour surface. Hardware assisted splatting is then employed on these data points to produce a volume rendering of the interval set. Finally, by shifting a small window through the indexing scheme or data space, animated volumes are produced showing the changing contour values. In addition to allowing fast selection and rendering of the data, the indexing scheme allows a much compressed representation of the data by eliminating ``noise`` data points.

  6. REAL TIME DATA FOR REMEDIATION ACTIVITIES [11505

    SciTech Connect

    BROCK CT

    2011-01-13

    Health physicists from the CH2M HILL Plateau Remediation Company collaborated with Berkeley Nucleonics Corporation to modify the SAM 940 isotope identifier instrument to be used for nuclear waste remediation. These modifications coupled with existing capabilities of the SAM 940 have proven to be invaluable during remediation activities, reducing disposal costs by allowing swift remediation of targeted areas that have been identified as having isotopes of concern (IOC), and eliminating multiple visits to sites by declaring an excavation site clear of IOCs before demobilizing from the site. These advantages are enabled by accumulating spectral data for specific isotopes that is nearly 100 percent free of false positives, which are filtered out in 'real time.'

  7. Real-time snapshot hyperspectral imaging endoscope.

    PubMed

    Kester, Robert T; Bedard, Noah; Gao, Liang; Tkaczyk, Tomasz S

    2011-05-01

    Hyperspectral imaging has tremendous potential to detect important molecular biomarkers of early cancer based on their unique spectral signatures. Several drawbacks have limited its use for in vivo screening applications: most notably the poor temporal and spatial resolution, high expense, and low optical throughput of existing hyperspectral imagers. We present the development of a new real-time hyperspectral endoscope (called the image mapping spectroscopy endoscope) based on an image mapping technique capable of addressing these challenges. The parallel high throughput nature of this technique enables the device to operate at frame rates of 5.2 frames per second while collecting a (x, y, λ) datacube of 350 × 350 × 48. We have successfully imaged tissue in vivo, resolving a vasculature pattern of the lower lip while simultaneously detecting oxy-hemoglobin. PMID:21639573

  8. Identifying financial crises in real time

    NASA Astrophysics Data System (ADS)

    da Fonseca, Eder Lucio; Ferreira, Fernando F.; Muruganandam, Paulsamy; Cerdeira, Hilda A.

    2013-03-01

    Following the thermodynamic formulation of a multifractal measure that was shown to enable the detection of large fluctuations at an early stage, here we propose a new index which permits us to distinguish events like financial crises in real time. We calculate the partition function from which we can obtain thermodynamic quantities analogous to the free energy and specific heat. The index is defined as the normalized energy variation and it can be used to study the behavior of stochastic time series, such as financial market daily data. Famous financial market crashes-Black Thursday (1929), Black Monday (1987) and the subprime crisis (2008)-are identified with clear and robust results. The method is also applied to the market fluctuations of 2011. From these results it appears as if the apparent crisis of 2011 is of a different nature to the other three. We also show that the analysis has forecasting capabilities.

  9. Real Time Correction of Aircraft Flight Fonfiguration

    NASA Technical Reports Server (NTRS)

    Schipper, John F. (Inventor)

    2009-01-01

    Method and system for monitoring and analyzing, in real time, variation with time of an aircraft flight parameter. A time-dependent recovery band, defined by first and second recovery band boundaries that are spaced apart at at least one time point, is constructed for a selected flight parameter and for a selected time recovery time interval length .DELTA.t(FP;rec). A flight parameter, having a value FP(t=t.sub.p) at a time t=t.sub.p, is likely to be able to recover to a reference flight parameter value FP(t';ref), lying in a band of reference flight parameter values FP(t';ref;CB), within a time interval given by t.sub.p.ltoreq.t'.ltoreq.t.sub.p.DELTA.t(FP;rec), if (or only if) the flight parameter value lies between the first and second recovery band boundary traces.

  10. Real-time forecasts of dengue epidemics

    NASA Astrophysics Data System (ADS)

    Yamana, T. K.; Shaman, J. L.

    2015-12-01

    Dengue is a mosquito-borne viral disease prevalent in the tropics and subtropics, with an estimated 2.5 billion people at risk of transmission. In many areas with endemic dengue, disease transmission is seasonal but prone to high inter-annual variability with occasional severe epidemics. Predicting and preparing for periods of higher than average transmission is a significant public health challenge. Here we present a model of dengue transmission and a framework for optimizing model simulations with real-time observational data of dengue cases and environmental variables in order to generate ensemble-based forecasts of the timing and severity of disease outbreaks. The model-inference system is validated using synthetic data and dengue outbreak records. Retrospective forecasts are generated for a number of locations and the accuracy of these forecasts is quantified.

  11. Intraoperative, real-time, functional MRI.

    PubMed

    Gering, D T; Weber, D M

    1998-01-01

    Functional MRI (fMRI) methods have been demonstrated to noninvasively identify motor-sensory, visual, and other areas of eloquent cortex for guiding surgical intervention. Typically, fMRI data are acquired preoperatively during a conventional surgical planning MRI examination. Unlike direct cortical stimulation at the time of surgery, however, preoperative fMRI methods do not account for the potential movement of tissues (relative to the time of functional imaging) that may occur in the surgical suite as a direct result of the intervention. Recently, an MRI device has been demonstrated for use in the surgical suite that has the potential to reduce the extent of cortical exposure required for the intervention. However, the invasive requirements of cortical mapping may supersede the invasive requirements of the surgical intervention itself. Consequently, we demonstrate here a modification to the intraoperative MRI device that facilitates a noninvasive, real-time, functional MR examination in the surgical suite.

  12. Near Real-Time Solar Image Reconstruction

    NASA Astrophysics Data System (ADS)

    Yang, G.; Denker, C.; Wang, H.

    2001-05-01

    We use a Linux Beowulf cluster to build a system for near real-time solar image reconstruction with the goal to obtain diffraction limited solar images at a cadence of one minute. This gives us immediate access to high-level data products and enables direct visualization of dynamic processes on the Sun. Space weather warnings and flare forecasting will benefit from this project. The image processing algorithms are based on the speckle masking method combined with frame selection. The parallel programs use explicit message passing via Parallel Virtual Machine (PVM). The preliminary results are very promising. Now, we can construct a 256 by 256 pixel image out of 50 short-exposure images within one minute on a Beowulf cluster with four 500~MHz CPUs. In addition, we want to explore the possibility of applying parallel computing on Beowulf clusters to other complex data reduction and analysis problems that we encounter, e.g., in multi-dimensional spectro-polarimetry.

  13. Near real-time stereo vision system

    NASA Technical Reports Server (NTRS)

    Anderson, Charles H. (Inventor); Matthies, Larry H. (Inventor)

    1993-01-01

    The apparatus for a near real-time stereo vision system for use with a robotic vehicle is described. The system is comprised of two cameras mounted on three-axis rotation platforms, image-processing boards, a CPU, and specialized stereo vision algorithms. Bandpass-filtered image pyramids are computed, stereo matching is performed by least-squares correlation, and confidence ranges are estimated by means of Bayes' theorem. In particular, Laplacian image pyramids are built and disparity maps are produced from the 60 x 64 level of the pyramids at rates of up to 2 seconds per image pair. The first autonomous cross-country robotic traverses (of up to 100 meters) have been achieved using the stereo vision system of the present invention with all computing done onboard the vehicle. The overall approach disclosed herein provides a unifying paradigm for practical domain-independent stereo ranging.

  14. Near real-time stereo vision system

    NASA Astrophysics Data System (ADS)

    Matthies, Larry H.; Anderson, Charles H.

    1991-12-01

    The apparatus for a near real-time stereo vision system for use with a robotic vehicle is described. The system is comprised of two cameras mounted on three-axis rotation platforms, image-processing boards, a CPU, and specialized stereo vision algorithms. Bandpass-filtered image pyramids are computed, stereo matching is performed by least-squares correlation, and confidence ranges are estimated by means of Bayes' theorem. In particular, Laplacian image pyramids are built and disparity maps are produced from the 60 x 64 level of the pyramids at rates of up to 2 seconds per image pair. The first autonomous cross-country robotic traverses (of up to 100 meters) have been achieved using the stereo vision system of the present invention with all computing done onboard the vehicle. The overall approach disclosed herein provides a unifying paradigm for practical domain-independent stereo ranging.

  15. Real time visualization of quantum walk

    SciTech Connect

    Miyazaki, Akihide; Hamada, Shinji; Sekino, Hideo

    2014-02-20

    Time evolution of quantum particles like electrons is described by time-dependent Schrödinger equation (TDSE). The TDSE is regarded as the diffusion equation of electrons with imaginary diffusion coefficients. And the TDSE is solved by quantum walk (QW) which is regarded as a quantum version of a classical random walk. The diffusion equation is solved in discretized space/time as in the case of classical random walk with additional unitary transformation of internal degree of freedom typical for quantum particles. We call the QW for solution of the TDSE a Schrödinger walk (SW). For observation of one quantum particle evolution under a given potential in atto-second scale, we attempt a successive computation and visualization of the SW. Using Pure Data programming, we observe the correct behavior of a probability distribution under the given potential in real time for observers of atto-second scale.

  16. Real-time value-driven diagnosis

    NASA Technical Reports Server (NTRS)

    Dambrosio, Bruce

    1995-01-01

    Diagnosis is often thought of as an isolated task in theoretical reasoning (reasoning with the goal of updating our beliefs about the world). We present a decision-theoretic interpretation of diagnosis as a task in practical reasoning (reasoning with the goal of acting in the world), and sketch components of our approach to this task. These components include an abstract problem description, a decision-theoretic model of the basic task, a set of inference methods suitable for evaluating the decision representation in real-time, and a control architecture to provide the needed continuing coordination between the agent and its environment. A principal contribution of this work is the representation and inference methods we have developed, which extend previously available probabilistic inference methods and narrow, somewhat, the gap between probabilistic and logical models of diagnosis.

  17. Real-time visualization of joint cavitation.

    PubMed

    Kawchuk, Gregory N; Fryer, Jerome; Jaremko, Jacob L; Zeng, Hongbo; Rowe, Lindsay; Thompson, Richard

    2015-01-01

    Cracking sounds emitted from human synovial joints have been attributed historically to the sudden collapse of a cavitation bubble formed as articular surfaces are separated. Unfortunately, bubble collapse as the source of joint cracking is inconsistent with many physical phenomena that define the joint cracking phenomenon. Here we present direct evidence from real-time magnetic resonance imaging that the mechanism of joint cracking is related to cavity formation rather than bubble collapse. In this study, ten metacarpophalangeal joints were studied by inserting the finger of interest into a flexible tube tightened around a length of cable used to provide long-axis traction. Before and after traction, static 3D T1-weighted magnetic resonance images were acquired. During traction, rapid cine magnetic resonance images were obtained from the joint midline at a rate of 3.2 frames per second until the cracking event occurred. As traction forces increased, real-time cine magnetic resonance imaging demonstrated rapid cavity inception at the time of joint separation and sound production after which the resulting cavity remained visible. Our results offer direct experimental evidence that joint cracking is associated with cavity inception rather than collapse of a pre-existing bubble. These observations are consistent with tribonucleation, a known process where opposing surfaces resist separation until a critical point where they then separate rapidly creating sustained gas cavities. Observed previously in vitro, this is the first in-vivo macroscopic demonstration of tribonucleation and as such, provides a new theoretical framework to investigate health outcomes associated with joint cracking.

  18. Real-Time Visualization of Joint Cavitation

    PubMed Central

    Rowe, Lindsay

    2015-01-01

    Cracking sounds emitted from human synovial joints have been attributed historically to the sudden collapse of a cavitation bubble formed as articular surfaces are separated. Unfortunately, bubble collapse as the source of joint cracking is inconsistent with many physical phenomena that define the joint cracking phenomenon. Here we present direct evidence from real-time magnetic resonance imaging that the mechanism of joint cracking is related to cavity formation rather than bubble collapse. In this study, ten metacarpophalangeal joints were studied by inserting the finger of interest into a flexible tube tightened around a length of cable used to provide long-axis traction. Before and after traction, static 3D T1-weighted magnetic resonance images were acquired. During traction, rapid cine magnetic resonance images were obtained from the joint midline at a rate of 3.2 frames per second until the cracking event occurred. As traction forces increased, real-time cine magnetic resonance imaging demonstrated rapid cavity inception at the time of joint separation and sound production after which the resulting cavity remained visible. Our results offer direct experimental evidence that joint cracking is associated with cavity inception rather than collapse of a pre-existing bubble. These observations are consistent with tribonucleation, a known process where opposing surfaces resist separation until a critical point where they then separate rapidly creating sustained gas cavities. Observed previously in vitro, this is the first in-vivo macroscopic demonstration of tribonucleation and as such, provides a new theoretical framework to investigate health outcomes associated with joint cracking. PMID:25875374

  19. A real-time pulsed photon dosimeter

    NASA Astrophysics Data System (ADS)

    Brown, David; Olsher, Richard H.; Eisen, Yosef; Rodriguez, Joseph F.

    1996-02-01

    Radiation sources producing short pulses of photon radiation are now widespread. Such sources include electron and proton linear accelerators, betatrons, synchrotrons, and field-emission impulse generators. It is often desirable to measure leakage and skyshine radiation from such sources in real time, on a single-pulse basis as low as 8.7 nGy (1 μR) per pulse. This paper describes the design and performance of a prototype, real-time, pulsed photon dosimeter (PPD) capable of single-pulse dose measurements over the range from 3.5 nGy to 3.5 μGy (0.4 to 400 μR). The PPD may also be operated in a multiple-pulse mode that integrates the dose from a train of radiation pulses over a 3-s period. A pulse repetition rate of up to 300 Hz is accommodated. The design is eminently suitable for packaging as a lightweight, portable, survey meter. The PPD uses a CdWO 4 scintillator optically coupled to a photodiode to generate a charge at the diode output. A pulse amplifier converts the charge to a voltage pulse. A digitizer circuit generates a burst of logic pulses whose number is proportional to the peak value of the voltage pulse. The digitizer output is recorded by a pulse counter and suitably displayed. A prototype PPD was built for testing and evaluation purposes. The performance of the PPD was evaluated with a variety of pulsed photon sources. The dynamic range, energy response, and response to multiple pulses were characterized. The experimental data confirm the viability of the PPD for pulsed photon dosimetry.

  20. Towards real time speckle controlled retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Bliedtner, Katharina; Seifert, Eric; Stockmann, Leoni; Effe, Lisa; Brinkmann, Ralf

    2016-03-01

    Photocoagulation is a laser treatment widely used for the therapy of several retinal diseases. Intra- and inter-individual variations of the ocular transmission, light scattering and the retinal absorption makes it impossible to achieve a uniform effective exposure and hence a uniform damage throughout the therapy. A real-time monitoring and control of the induced damage is highly requested. Here, an approach to realize a real time optical feedback using dynamic speckle analysis is presented. A 532 nm continuous wave Nd:YAG laser is used for coagulation. During coagulation, speckle dynamics are monitored by a coherent object illumination using a 633nm HeNe laser and analyzed by a CMOS camera with a frame rate up to 1 kHz. It is obvious that a control system needs to determine whether the desired damage is achieved to shut down the system in a fraction of the exposure time. Here we use a fast and simple adaption of the generalized difference algorithm to analyze the speckle movements. This algorithm runs on a FPGA and is able to calculate a feedback value which is correlated to the thermal and coagulation induced tissue motion and thus the achieved damage. For different spot sizes (50-200 μm) and different exposure times (50-500 ms) the algorithm shows the ability to discriminate between different categories of retinal pigment epithelial damage ex-vivo in enucleated porcine eyes. Furthermore in-vivo experiments in rabbits show the ability of the system to determine tissue changes in living tissue during coagulation.

  1. A tool for modeling concurrent real-time computation

    NASA Technical Reports Server (NTRS)

    Sharma, D. D.; Huang, Shie-Rei; Bhatt, Rahul; Sridharan, N. S.

    1990-01-01

    Real-time computation is a significant area of research in general, and in AI in particular. The complexity of practical real-time problems demands use of knowledge-based problem solving techniques while satisfying real-time performance constraints. Since the demands of a complex real-time problem cannot be predicted (owing to the dynamic nature of the environment) powerful dynamic resource control techniques are needed to monitor and control the performance. A real-time computation model for a real-time tool, an implementation of the QP-Net simulator on a Symbolics machine, and an implementation on a Butterfly multiprocessor machine are briefly described.

  2. Approaching near real-time biosensing: microfluidic microsphere based biosensor for real-time analyte detection.

    PubMed

    Cohen, Noa; Sabhachandani, Pooja; Golberg, Alexander; Konry, Tania

    2015-04-15

    In this study we describe a simple lab-on-a-chip (LOC) biosensor approach utilizing well mixed microfluidic device and a microsphere-based assay capable of performing near real-time diagnostics of clinically relevant analytes such cytokines and antibodies. We were able to overcome the adsorption kinetics reaction rate-limiting mechanism, which is diffusion-controlled in standard immunoassays, by introducing the microsphere-based assay into well-mixed yet simple microfluidic device with turbulent flow profiles in the reaction regions. The integrated microsphere-based LOC device performs dynamic detection of the analyte in minimal amount of biological specimen by continuously sampling micro-liter volumes of sample per minute to detect dynamic changes in target analyte concentration. Furthermore we developed a mathematical model for the well-mixed reaction to describe the near real time detection mechanism observed in the developed LOC method. To demonstrate the specificity and sensitivity of the developed real time monitoring LOC approach, we applied the device for clinically relevant analytes: Tumor Necrosis Factor (TNF)-α cytokine and its clinically used inhibitor, anti-TNF-α antibody. Based on the reported results herein, the developed LOC device provides continuous sensitive and specific near real-time monitoring method for analytes such as cytokines and antibodies, reduces reagent volumes by nearly three orders of magnitude as well as eliminates the washing steps required by standard immunoassays.

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

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

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

  4. Clinical experience with real-time ultrasound

    NASA Astrophysics Data System (ADS)

    Chimiak, William J.; Wolfman, Neil T.; Covitz, Wesley

    1995-05-01

    After testing the extended multimedia interface (EMMI) product which is an asynchronous transmission mode (ATM) user to network interface (UNI) of AT&T at the Society for Computer Applications in Radiology conference in Winston-Salem, the Department of Radiology together with AT&T are implementing a tele-ultrasound system to combine real- time ultrasound with the static imaging features of more traditional digital ultrasound systems. Our current ultrasound system archives digital images to an optical disk system. Static images are sent using our digital radiology systems. This could be transferring images from one digital imaging and communications (DICOM)-compliant machine to another, or the current image transfer methodologies. The prototype of a live ultrasound system using the EMMI demonstrated the feasibility of doing live ultrasound. We now are developing the scenarios using a mix of the two methodologies. Utilizing EMMI technology, radiologists at the BGSM review at a workstation both static images and real-time scanning done by a technologist on patients at a remote site in order to render on-line primary diagnosis. Our goal is to test the feasibility of operating an ultrasound laboratory at a remote site utilizing a trained technologist without the necessity of having a full-time radiologist at that site. Initial plans are for a radiologist to review an initial set of static images on a patient taken by the technologist. If further scanning is required, the EMMI is used to transmit real-time imaging and audio using the audio input of a standard microphone system and the National Television Standards Committee (NTSC) output of the ultrasound equipment from the remote site to the radiologist in the department review station. The EMMI digitally encodes this data and places it in an ATM format. This ATM data stream goes to the GCNS2000 and then to the other EMMI where the ATM data stream is decoded into the live studies and voice communication which are then

  5. Real Time Earthquake Information System in Japan

    NASA Astrophysics Data System (ADS)

    Doi, K.; Kato, T.

    2003-12-01

    An early earthquake notification system in Japan had been developed by the Japan Meteorological Agency (JMA) as a governmental organization responsible for issuing earthquake information and tsunami forecasts. The system was primarily developed for prompt provision of a tsunami forecast to the public with locating an earthquake and estimating its magnitude as quickly as possible. Years after, a system for a prompt provision of seismic intensity information as indices of degrees of disasters caused by strong ground motion was also developed so that concerned governmental organizations can decide whether it was necessary for them to launch emergency response or not. At present, JMA issues the following kinds of information successively when a large earthquake occurs. 1) Prompt report of occurrence of a large earthquake and major seismic intensities caused by the earthquake in about two minutes after the earthquake occurrence. 2) Tsunami forecast in around three minutes. 3) Information on expected arrival times and maximum heights of tsunami waves in around five minutes. 4) Information on a hypocenter and a magnitude of the earthquake, the seismic intensity at each observation station, the times of high tides in addition to the expected tsunami arrival times in 5-7 minutes. To issue information above, JMA has established; - An advanced nationwide seismic network with about 180 stations for seismic wave observation and about 3,400 stations for instrumental seismic intensity observation including about 2,800 seismic intensity stations maintained by local governments, - Data telemetry networks via landlines and partly via a satellite communication link, - Real-time data processing techniques, for example, the automatic calculation of earthquake location and magnitude, the database driven method for quantitative tsunami estimation, and - Dissemination networks, via computer-to-computer communications and facsimile through dedicated telephone lines. JMA operationally

  6. CRANS - CONFIGURABLE REAL-TIME ANALYSIS SYSTEM

    NASA Technical Reports Server (NTRS)

    Mccluney, K.

    1994-01-01

    In a real-time environment, the results of changes or failures in a complex, interconnected system need evaluation quickly. Tabulations showing the effects of changes and/or failures of a given item in the system are generally only useful for a single input, and only with regard to that item. Subsequent changes become harder to evaluate as combinations of failures produce a cascade effect. When confronted by multiple indicated failures in the system, it becomes necessary to determine a single cause. In this case, failure tables are not very helpful. CRANS, the Configurable Real-time ANalysis System, can interpret a logic tree, constructed by the user, describing a complex system and determine the effects of changes and failures in it. Items in the tree are related to each other by Boolean operators. The user is then able to change the state of these items (ON/OFF FAILED/UNFAILED). The program then evaluates the logic tree based on these changes and determines any resultant changes to other items in the tree. CRANS can also search for a common cause for multiple item failures, and allow the user to explore the logic tree from within the program. A "help" mode and a reference check provide the user with a means of exploring an item's underlying logic from within the program. A commonality check determines single point failures for an item or group of items. Output is in the form of a user-defined matrix or matrices of colored boxes, each box representing an item or set of items from the logic tree. Input is via mouse selection of the matrix boxes, using the mouse buttons to toggle the state of the item. CRANS is written in C-language and requires the MIT X Window System, Version 11 Revision 4 or Revision 5. It requires 78K of RAM for execution and a three button mouse. It has been successfully implemented on Sun4 workstations running SunOS, HP9000 workstations running HP-UX, and DECstations running ULTRIX. No executable is provided on the distribution medium; however

  7. A Case of Sustained Intraocular Pressure Elevation after Multiple Intravitreal Injection of Ranibizumab and Aflibercept for Neovascular Age-Related Macular Degeneration

    PubMed Central

    Matsubara, Hisashi; Miyata, Ryohei; Kobayashi, Maki; Tsukitome, Hideyuki; Ikesugi, Kengo; Kondo, Mineo

    2016-01-01

    Intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents are widely used to treat neovascular age-related macular degeneration (nAMD). Although these treatments are effective, multiple injections have recently been recommended to ensure that there is a good long-term prognosis. However, sustained intraocular pressure (IOP) elevations have been reported to develop after multiple injections of anti-VEGF agents. We present our findings of a case of uncontrolled and persistent IOP elevation after switching from intravitreal ranibizumab injections to intravitreal aflibercept injections. A 74-year-old Japanese man without a history of glaucoma underwent 22 ranibizumab injections for nAMD and suddenly developed an elevated IOP after the 22nd injection. Although the subsequent medical treatment led to normalization of his IOP, the subretinal fluid under the central fovea remained even after the 25th injection of ranibizumab. Thus, ranibizumab treatment was switched to bimonthly intravitreal aflibercept injections in conjunction with glaucoma medications. His IOP recovered to within the normal range; however, after the 11th aflibercept injection, there was a sudden elevation of his IOP in spite of the continued glaucoma medications. Due to this sustained IOP elevation, his aflibercept injections were suspended for 16 weeks. Because his IOP could not be normalized by a full glaucoma medication regimen, the patient underwent trabeculotomy, which resulted in a lowering of the IOP to normal levels. We conclude that patients who receive serial intravitreal injections of anti-VEGF agents need to be closely monitored because severe and sustained ocular hypertension can develop. PMID:27462248

  8. Numerical analysis of specific absorption rate in the human head due to a 13.56 MHz RFID-based intra-ocular pressure measurement system.

    PubMed

    Hirtl, Rene; Schmid, Gernot

    2013-09-21

    A modern wireless intra-ocular pressure monitoring system, based on 13.56 MHz inductively coupled data transmission, was dosimetrically analyzed with respect to the specific absorption rate (SAR) induced inside the head and the eye due to the electromagnetic field exposure caused by the reader antenna of the transmission system. The analysis was based on numerical finite difference time domain computations using a high resolution anatomical eye model integrated in a modern commercially available anatomical model of a male head. Three different reader antenna configurations, a 7-turn elliptic (30 mm × 50 mm) antenna at 12 mm distance from the eye, a flexible circular antenna (60 mm diameter, 8 turns on 2 mm substrate) directly attached to the skin, and a circular 7-turn antenna (30 mm diameter at 12 mm distance to the eye) were analyzed, respectively. Possible influences of the eye-lid status (closed or opened) and the transponder antenna contained in a contact lens directly attached to the eye were taken into account. The results clearly demonstrated that for typical reader antenna currents required for proper data transmission, the SAR values remain far below the limits for localized exposure of the head, as defined by the International Commission for Non-Ionizing Radiation Protection. Particularly the induced SAR inside the eye was found to be substantially (orders of magnitudes for typical reader antenna currents in the order of 1 A turn) below values which have been reported to be critical with respect to thermally induced adverse health effects in eye tissues. PMID:24002053

  9. Agreement between diurnal variations of intraocular pressure by Tono-Pen and Goldmann applanation tonometer in patients on topical anti-glaucoma medication.

    PubMed

    Gupta, Shikha; Sinha, Gautam; Sharma, Reetika; Nayak, Bhagabat; Patil, Bharat; Kashyap, Bibhuti; Shameer, Abdul; Dada, Tanuj

    2016-02-01

    To estimate agreement in diurnal variations of intraocular pressure (IOP) by Tono-Pen (TP) and Goldmann applanation tonometer (GAT) in glaucoma patients on topical anti-glaucoma medication(s). IOP was measured at every 3 h from 7 a.m. to 10 a.m. in 50 eyes of glaucoma patients on topical medication(s). Diurnal fluctuation of IOP by each method was calculated as maximum-minimum IOP in a day. Central corneal thickness (CCT) was measured by ultrasonic pachymeter. There was good correlation between TP and GAT at all times during a day, minimum, and maximum IOPs during a day (Correlation coefficient, 0.706 at 7 a.m., 0.624 at 10 a.m., 0.682 at 1 p.m., 0.814 at 4 p.m., 0.652 at 7 p.m., 0.572 at 10 p.m., 0.668 minimum IOP, 0.689 maximum IOP). Mean IOPs by TP were always higher than GAT at all times during a day. Bland-Altman plots suggested a close relationship between the two sets of readings, and that this relationship was consistent at different times in a day, in maximum IOPs, minimum IOPs and also in fluctuation of IOPs. Linear regression analysis between the differences of diurnal fluctuation (diurnal fluctuation by GAT-diurnal fluctuation by TP) and CCT showed strong association (R 2 = 0.857, p < 0.001). The mean change in difference of diurnal fluctuation (GAT-TP) for a 10-micron increase in CCT was 0.69 mmHg. TP can be considered a reliable alternative to GAT in glaucoma patients for knowing the diurnal control of IOP; however these two methods should not be used interchangeably. Difference of diurnal fluctuation between two methods is dependent on CCT.

  10. Intraocular pressure control with Ahmed glaucoma drainage device in patients with cicatricial ocular surface disease-associated or aniridia-related glaucoma.

    PubMed

    Almousa, Radwan; Lake, Damian B

    2014-08-01

    To analyze the control of intraocular pressure (IOP) with an Ahmed glaucoma drainage device (AGDD) in two groups of glaucoma patients--one with cicatricial ocular surface disease (COSD) and one with aniridia. This is a retrospective comparative case series of nine patients (11 eyes) with COSD and six patients (8 eyes) with aniridia who underwent AGDD surgery to control IOP. The main outcome measure in both groups was stability of IOP between 6 and 21 mmHg. Mean IOP decreased significantly in both groups after AGDD surgery (29.6 ± 8.7 vs 14.7 ± 2.5, p = 0.008 in the COSD group; 26.3 ± 8.2 vs 15.3 ± 5.8, p = 0.008 in the aniridia group). Over a mean post-surgery follow-up of 37.1 months in the COSD group, we managed to control IOP in nine eyes; IOP control was successful in 87 % of eyes at 12 months and 58 % of eyes at 26 months. Over a mean post-surgery follow-up of 37.4 months in the aniridia group, we managed to control the IOP in seven eyes; IOP control was successful in 87 % of eyes at 12 months. AGDD surgery had no significant deleterious effect on visual acuity in either group. A severe complication occurred in one eye (1/8) in the aniridia group (lost vision due to retinal detachment) and in one eye (1/11) in the COSD group (tube exposure). AGDD surgery is effective in controlling IOP and has a low complication rate in COSD and aniridia patients; however, some of the complications are severe and prompt management is needed to prevent deleterious results.

  11. A genome-wide association study of intra-ocular pressure suggests a novel association in the gene FAM125B in the TwinsUK cohort.

    PubMed

    Nag, Abhishek; Venturini, Cristina; Small, Kerrin S; Young, Terri L; Viswanathan, Ananth C; Mackey, David A; Hysi, Pirro G; Hammond, Christopher

    2014-06-15

    Glaucoma is a major cause of blindness in the world. To date, common genetic variants associated with glaucoma only explain a small proportion of its heritability. We performed a genome-wide association study of intra-ocular pressure (IOP), an underlying endophenotype for glaucoma. The discovery phase of the study was carried out in the TwinsUK cohort (N = 2774) analyzing association between IOP and single nucleotide polymorphisms (SNPs) imputed to HapMap2. The results were validated in 12 independent replication cohorts of European ancestry (combined N = 22 789) that were a part of the International Glaucoma Genetics Consortium. Expression quantitative trait locus (eQTL) analyses of the significantly associated SNPs were performed using data from the Multiple Tissue Human Expression Resource (MuTHER) Study. In the TwinsUK cohort, IOP was significantly associated with a number of SNPs at 9q33.3 (P = 3.48 × 10(-8) for rs2286885, the most significantly associated SNP at this locus), within the genomic sequence of the FAM125B gene. Independent replication in a composite panel of 12 cohorts revealed consistent direction of effect and significant association (P = 0.003, for fixed-effect meta-analysis). Suggestive evidence for an eQTL effect of rs2286885 was observed for one of the probes targeting the coding region of the FAM125B gene. This gene codes for a component of a membrane complex involved in vesicular trafficking process, a function similar to that of the Caveolin genes (CAV1 and CAV2) which have previously been associated with primary open-angle glaucoma. This study suggests a novel association between SNPs in FAM125B and IOP in the TwinsUK cohort, though further studies to elucidate the functional role of this gene in glaucoma are necessary.

  12. Eyes with Suspicious Appearance of the Optic Disc and Normal Intraocular Pressure: Using Clinical and Epidemiological Characteristics to Differentiate Those with and without Glaucoma

    PubMed Central

    Sousa, Marina C.; Dorairaj, Syril; Biteli, Luis G.

    2016-01-01

    Among all glaucoma suspects, eyes with optic nerve head features suspicious or suggestive of early glaucoma are probably those that offer the greatest challenge for clinicians. In contrast with the robust longitudinal data published on ocular hypertension, there is no specific management guideline for these patients. Therefore, evaluating eyes with suspicious optic disc appearance and normal intraocular pressure (IOP), we sought to investigate potential differences in clinical and epidemiological characteristics to differentiate those with normal-tension glaucoma (NTG) from those with presumed large physiological optic disc cups (pLPC). In this observational case-control study, we consecutively enrolled individuals with pLPC and NTG. All eyes had vertical cup-to-disc ratio (VCDR)≥0.6 and untreated IOP<21 mmHg. Glaucomatous eyes had reproducible visual field defects. Eyes with pLPC required normal visual fields and ≥30 months of follow-up with no evidence of glaucomatous neuropathy. Clinical and epidemiological parameters were compared between groups. Eighty-four individuals with pLPC and 40 NTG patients were included. Regarding our main results, NTG patients were significantly older and with a higher prevalence of Japanese descendants (p<0.01). Not only did pLPC eyes have smaller mean VCDR, but also larger optic discs (p≤0.04). There were no significant differences for gender, central corneal thickness, and spherical equivalent (p≥0.38). Significant odds ratios (OR) were found for race (OR = 2.42; for Japanese ancestry), age (OR = 1.05), VCDR (OR = 5.03), and disc size (OR = 0.04; p≤0.04). In conclusion, in patients with suspicious optic disc and normal IOP, those with older age, Japanese ancestry, smaller optic discs, and larger VCDR are more likely to have NTG, and therefore, deserve deeper investigation and closer monitoring. PMID:27433805

  13. Three Toxic Heavy Metals in Open-Angle Glaucoma with Low-Teen and High-Teen Intraocular Pressure: A Cross-Sectional Study from South Korea

    PubMed Central

    Lee, Si Hyung; Kang, Eun Min; Kim, Gyu Ah; Kwak, Seung Woo; Kim, Joon Mo; Bae, Hyoung Won; Seong, Gong Je; Kim, Chan Yun

    2016-01-01

    Background To investigate the association between heavy metal levels and open-angle glaucoma (OAG) with low- and high-teen baseline intraocular pressure (IOP) using a population-based study design. Methods This cross-sectional study included 5,198 participants older than 19 years of age who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2012 and had blood heavy metal levels available. The OAG with normal baseline IOP (IOP ≤ 21 mmHg) subjects were stratified into low-teen OAG (baseline IOP ≤ 15 mmHg) and high-teen OAG (15 mmHg < baseline IOP ≤ 21 mmHg), and the association between blood lead, mercury, and cadmium levels and glaucoma prevalence was assessed for low- and high-teen OAG. Results The adjusted geometric mean of blood cadmium levels was significantly higher in subjects with low-teen OAG than that of the non-glaucomatous group (P = 0.028), whereas there were no significant differences in blood lead and mercury levels. After adjusting for potential confounders, the low-teen OAG was positively associated with log-transformed blood cadmium levels (OR, 1.41; 95% confidence interval (CI), 1.03–1.93; P = 0.026). For high-teen OAG, log-transformed blood levels of the three heavy metals were not associated with disease prevalence. The association between log-transformed blood cadmium levels and low-teen OAG was significant only in men (OR, 1.65; 95% CI, 1.10–2.48; P = 0.016), and not in women (OR, 1.10; 95% CI, 0.66–1.85; P = 0.709). Conclusions The results of this study suggest that cadmium toxicity could play a role in glaucoma pathogenesis, particularly in men and in OAG with low-teen baseline IOP. PMID:27768724

  14. Numerical analysis of specific absorption rate in the human head due to a 13.56 MHz RFID-based intra-ocular pressure measurement system

    NASA Astrophysics Data System (ADS)

    Hirtl, Rene; Schmid, Gernot

    2013-09-01

    A modern wireless intra-ocular pressure monitoring system, based on 13.56 MHz inductively coupled data transmission, was dosimetrically analyzed with respect to the specific absorption rate (SAR) induced inside the head and the eye due to the electromagnetic field exposure caused by the reader antenna of the transmission system. The analysis was based on numerical finite difference time domain computations using a high resolution anatomical eye model integrated in a modern commercially available anatomical model of a male head. Three different reader antenna configurations, a 7-turn elliptic (30 mm × 50 mm) antenna at 12 mm distance from the eye, a flexible circular antenna (60 mm diameter, 8 turns on 2 mm substrate) directly attached to the skin, and a circular 7-turn antenna (30 mm diameter at 12 mm distance to the eye) were analyzed, respectively. Possible influences of the eye-lid status (closed or opened) and the transponder antenna contained in a contact lens directly attached to the eye were taken into account. The results clearly demonstrated that for typical reader antenna currents required for proper data transmission, the SAR values remain far below the limits for localized exposure of the head, as defined by the International Commission for Non-Ionizing Radiation Protection. Particularly the induced SAR inside the eye was found to be substantially (orders of magnitudes for typical reader antenna currents in the order of 1 A turn) below values which have been reported to be critical with respect to thermally induced adverse health effects in eye tissues.

  15. Real-time reconfigurable subthreshold CMOS perceptron.

    PubMed

    Aunet, S; Oelmann, B; Norseng, P A; Berg, Y

    2008-04-01

    In this paper, a new, real-time reconfigurable perceptron circuit element is presented. A six-transistor version used as a threshold gate, having a fan-in of three, producing adequate outputs for threshold of T =1, 2 and 3 is demonstrated by chip measurements. Subthreshold operation for supply voltages in the range of 100-350 mV is shown. The circuit performs competitively with a standard static complimentary metal-oxide-semiconductor (CMOS) implementation when maximum speed and energy delay product are taken into account, when used in a ring oscillator. Functionality per transistor is, to our knowledge, the highest reported for a variety of comparable circuits not based on floating gate techniques. Statistical simulations predict probabilities for making working circuits under mismatch and process variations. The simulations, in 120-nm CMOS, also support discussions regarding lower limits to supply voltage and redundancy. A brief discussion on how the circuit may be exploited as a basic building block for future defect tolerant mixed signal circuits, as well as neural networks, exploiting redundancy, is included.

  16. Real-Time Principal-Component Analysis

    NASA Technical Reports Server (NTRS)

    Duong, Vu; Duong, Tuan

    2005-01-01

    A recently written computer program implements dominant-element-based gradient descent and dynamic initial learning rate (DOGEDYN), which was described in Method of Real-Time Principal-Component Analysis (NPO-40034) NASA Tech Briefs, Vol. 29, No. 1 (January 2005), page 59. To recapitulate: DOGEDYN is a method of sequential principal-component analysis (PCA) suitable for such applications as data compression and extraction of features from sets of data. In DOGEDYN, input data are represented as a sequence of vectors acquired at sampling times. The learning algorithm in DOGEDYN involves sequential extraction of principal vectors by means of a gradient descent in which only the dominant element is used at each iteration. Each iteration includes updating of elements of a weight matrix by amounts proportional to a dynamic initial learning rate chosen to increase the rate of convergence by compensating for the energy lost through the previous extraction of principal components. In comparison with a prior method of gradient-descent-based sequential PCA, DOGEDYN involves less computation and offers a greater rate of learning convergence. The sequential DOGEDYN computations require less memory than would parallel computations for the same purpose. The DOGEDYN software can be executed on a personal computer.

  17. Real-Time 3D Visualization

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Butler Hine, former director of the Intelligent Mechanism Group (IMG) at Ames Research Center, and five others partnered to start Fourth Planet, Inc., a visualization company that specializes in the intuitive visual representation of dynamic, real-time data over the Internet and Intranet. Over a five-year period, the then NASA researchers performed ten robotic field missions in harsh climes to mimic the end- to-end operations of automated vehicles trekking across another world under control from Earth. The core software technology for these missions was the Virtual Environment Vehicle Interface (VEVI). Fourth Planet has released VEVI4, the fourth generation of the VEVI software, and NetVision. VEVI4 is a cutting-edge computer graphics simulation and remote control applications tool. The NetVision package allows large companies to view and analyze in virtual 3D space such things as the health or performance of their computer network or locate a trouble spot on an electric power grid. Other products are forthcoming. Fourth Planet is currently part of the NASA/Ames Technology Commercialization Center, a business incubator for start-up companies.

  18. Correction of deformed images in real time

    NASA Astrophysics Data System (ADS)

    Van der Jeught, Sam; Buytaert, Jan A. N.; Dirckx, Joris J. J.

    2011-09-01

    Optical lens systems generally contain non-linear distortion artifacts that impose important limitations on the direct interpretation of the images. Image processing can be used to correct for these artifacts, but due to the calculation-intensive nature of the required distortion correction process, this is usually performed offline. This is not an option in image-based applications that operate interactively, however, where the real-time display of distortion corrected images can be vital. To this end, we propose a new technique to correct for arbitrary geometric lens distortion that uses the parallel processing power of a commercial graphics processing unit (GPU). By offloading the distortion correction process to the GPU, we can relieve the central processing unit (CPU) of doing this computationally very demanding task. We successfully implemented the full distortion correction algorithm on the GPU, thereby achieving a display rate of over 30 frames/sec for fully processed images of size 1024 × 768 pixels without the need for any additional digital image processing hardware.

  19. Real time radiation measurements in space

    NASA Astrophysics Data System (ADS)

    Thomson, I.; Mackay, G.

    Radiation composed of energetic electrons, protons, photons, and galactic cosmic rays will be experienced by all space missions and may have effects on radiation sensitive electronic components and biological specimens. Radiation issues of interest to microgravity and biological experiments are discussed and the design of a new direct reading electronic radiation monitoring system is described. The proposed system consists of a radiation sensitive metal oxide semiconductor field effect transistor (MOSFET) specially designed to respond to ionizing radiation. On exposure to radiation, a permanent charge is stored in the MOSFET's insulating oxide, altering the device's electrical characteristics in a manner directly proportional to the dose exposed. A simple circuit reads the MOSFET's cumulative dose, making it possible to obtain real-time measurements and store the data or transfer the data to an earth station. Tests have shown that the MOSFET dosimeter shows a linear response up to at least 30,000 centiGray at a resolution of 0.1 centiGray. The MOSFET dosimetry system will be installed on the European Space Agency's ARTEP satellite scheduled for launch in November 1991.

  20. Extrasolar Giant Impacts in Real Time

    NASA Astrophysics Data System (ADS)

    Rieke, George; Meng, Huan; Su, Kate

    2013-10-01

    Spitzer observations in the previous cycles have revealed 3.6 and 4.5 um variability and periodicity in extreme debris disks on timescales of weeks or even shorter. Such disks typically have warm temperatures and strong crystalline silicate emission, indicative of very fine dust particles in the terrestrial planet zone and below the blowout sizes of the stars. Many of the disks are around solar-like stars in the age range of 30 - 100+ Myr, the expected time for the final buildup of terrestrial planets through massive collisions. These young extrasolar systems are probably going through this phase with series of violent collisions, or possible analogs of the Moon-forming impact, providing rare opportunities to investigate terrestrial planet formation and collision in real time, and put our own Solar System in context. Here we propose to continue the monitoring of three such systems with daily sampling cadence. The observations will provide insight into the physical and dynamical processes of the planet-forming disks.

  1. Optimizing near real time accountability for reprocessing.

    SciTech Connect

    Cipiti, Benjamin B.

    2010-06-01

    Near Real Time Accountability (NRTA) of actinides at high precision in reprocessing plants has been a long sought-after goal in the safeguards community. Achieving this goal is hampered by the difficulty of making precision measurements in the reprocessing environment, equipment cost, and impact to plant operations. Thus the design of future reprocessing plants requires an optimization of different approaches. The Separations and Safeguards Performance Model, developed at Sandia National Laboratories, was used to evaluate a number of NRTA strategies in a UREX+ reprocessing plant. Strategies examined include the incorporation of additional actinide measurements of internal plant vessels, more use of process monitoring data, and the option of periodic draining of inventory to key tanks. Preliminary results show that the addition of measurement technologies can increase the overall measurement uncertainty due to additional error propagation, so care must be taken when designing an advanced system. Initial results also show that relying on a combination of different NRTA techniques will likely be the best option. The model provides a platform for integrating all the data. The modeling results for the different NRTA options under various material loss conditions will be presented.

  2. High sensitivity real-time NVR monitor

    NASA Technical Reports Server (NTRS)

    Bowers, William D. (Inventor); Chuan, Raymond L. (Inventor)

    1997-01-01

    A real time non-volatile residue (NVR) monitor, which utilizes surface acoustic wave (SAW) resonators to detect molecular contamination in a given environment. The SAW resonators operate at a resonant frequency of approximately 200 MHz-2,000 MHz which enables the NVR monitor to detect molecular contamination on the order of 10.sup.-11 g-cm.sup.-2 to 10.sup.-13 g-cm.sup.2. The NVR monitor utilizes active temperature control of (SAW) resonators to achieve a stable resonant frequency. The temperature control system of the NVR monitor is able to directly heat and cool the SAW resonators utilizing a thermoelectric element to maintain the resonators at a present temperature independent of the environmental conditions. In order to enable the direct heating and cooling of the SAW resonators, the SAW resonators are operatively mounted to a heat sink. In one embodiment, the heat sink is located in between the SAW resonators and an electronic circuit board which contains at least a portion of the SAW control electronics. The electrical leads of the SAW resonators are connected through the heat sink to the circuit board via an electronic path which prevents inaccurate frequency measurement.

  3. Real-time scheduling of software tasks

    SciTech Connect

    Hoff, L.T.

    1995-12-01

    When designing real-time systems, it is often desirable to schedule execution of software tasks based on the occurrence of events. The events may be clock ticks, interrupts from a hardware device, or software signals from other software tasks. If the nature of the events, is well understood, this scheduling is normally a static part of the system design. If the nature of the events is not completely understood, or is expected to change over time, it may be necessary to provide a mechanism for adjusting the scheduling of the software tasks. RHIC front-end computers (FECs) provide such a mechanism. The goals in designing this mechanism were to be as independent as possible of the underlying operating system, to allow for future expansion of the mechanism to handle new types of events, and to allow easy configuration. Some considerations which steered the design were programming paradigm (object oriented vs. procedural), programming language, and whether events are merely interesting moments in time, or whether they intrinsically have data associated with them. The design also needed to address performance and robustness tradeoffs involving shared task contexts, task priorities, and use of interrupt service routine (ISR) contexts vs. task contexts. This paper will explore these considerations and tradeoffs.

  4. Real-time video watermarking technique

    NASA Astrophysics Data System (ADS)

    Lee, Han H.; Chae, Jong J.; Choi, Jong U.

    2002-04-01

    Most previous video watermarking algorithms cannot be supported by real-time processing. Our algorithm proposed the specific embedding method in the spatial domain directly rather than the frequency domain. Also the algorithm supports the robustness from the video attacking skills. In the paper, for example, watermark is inserted immediately into the output frame of Digital Video (DV) camcorder. We select the Y component from the DV signal, and then the watermark information is inserted in all of the Y frames. The watermarked video frames put in the video MPEG encoder. We consider embedding information to the high quality video streams, such as a DVD, HDTV. Our experimental results show the high quality of the video even if compressed. Therefore, the robustness from compression is tested by MPEG-2 of 6Mbits/sec of 720x480 frame size and the invisibility is proved by measurement of PSNR. The results also show the robustness from several video editing methods, such as a cut-and-splice and cut-insert-splice, and video conversions, letterboxing, pan & span, and wide screen of media.

  5. Real-time optoacoustic monitoring of stroke

    NASA Astrophysics Data System (ADS)

    Kneipp, Moritz; Turner, Jake; Hambauer, Sebastian; Krieg, Sandro M.; Lehmberg, Jens; Lindauer, Ute; Razansky, Daniel

    2014-03-01

    Characterizing disease progression and identifying possible therapeutic interventions in stroke is greatly aided by the use of longitudinal function imaging studies. In this study, we investigate the applicability of real-time multispectral optoacoustic tomography (MSOT) as a tool for non-invasive monitoring of the progression of stroke in the whole brain. The middle cerebral artery occlusion (MCAO) method was used to induce stroke. Mice were imaged under isoflurane anesthesia preoperatively and at several time points during and after the 60-minute occlusion. The animals were sacrificed after 24 hours and their excised brains frozen at -80°C for sectioning. The cryosection were stained using H&E staining to identify the ischemic lesion. Major vessels are readily identifiable in the whole mouse head in the in vivo optoacoustic scans. During ischemia, a reduction in cerebral blood volume is detectable in the cortex. Post ischemia, spectral unmixing of the optoacoustic signals shows an asymmetry of the deoxygenated hemoglobin in the hemisphere affected by MCAO. This hypoxic area was mainly located around the boundary of the ischemic lesion and was therefore identified as the ischemic penumbra. Non-invasive functional MSOT imaging is able to visualize the hypoxic penumbra in brains affected by stroke. Stopping the spread of the infarct area and revitalizing the penumbra is central in stroke research, this new imaging technique may therefore prove to be a valuable tool in the monitoring and developing new treatments.

  6. Recommendations for Real-Time Speech MRI

    PubMed Central

    Lingala, Sajan Goud; Sutton, Brad P.; Miquel, Marc E.; Nayak, Krishna S.

    2016-01-01

    Real-time magnetic resonance imaging (RT-MRI) is being increasingly used for speech and vocal production research studies. Several imaging protocols have emerged based on advances in RT-MRI acquisition, reconstruction, and audio-processing methods. This review summarizes the state-of-the-art, discusses technical considerations, and provides specific guidance for new groups entering this field. We provide recommendations for performing RT-MRI of the upper airway. This is a consensus statement stemming from the ISMRM-endorsed Speech MRI summit held in Los Angeles, February 2014. A major unmet need identified at the summit was the need for consensus on protocols that can be easily adapted by researchers equipped with conventional MRI systems. To this end, we provide a discussion of tradeoffs in RT-MRI in terms of acquisition requirements, a priori assumptions, artifacts, computational load, and performance for different speech tasks. We provide four recommended protocols and identify appropriate acquisition and reconstruction tools. We list pointers to open-source software that facilitate implementation. We conclude by discussing current open challenges in the methodological aspects of RT-MRI of speech. PMID:26174802

  7. Real-time information management environment (RIME)

    NASA Astrophysics Data System (ADS)

    DeCleene, Brian T.; Griffin, Sean; Matchett, Garry; Niejadlik, Richard

    2000-08-01

    Whereas data mining and exploitation improve the quality and quantity of information available to the user, there remains a mission requirement to assist the end-user in managing the access to this information and ensuring that the appropriate information is delivered to the right user in time to make decisions and take action. This paper discusses TASC's federated architecture to next- generation information management, contrasts the approach against emerging technologies, and quantifies the performance gains. This architecture and implementation, known as Real-time Information Management Environment (RIME), is based on two key concepts: information utility and content-based channelization. The introduction of utility allows users to express the importance and delivery requirements of their information needs in the context of their mission. Rather than competing for resources on a first-come/first-served basis, the infrastructure employs these utility functions to dynamically react to unanticipated loading by optimizing the delivered information utility. Furthermore, commander's resource policies shape these functions to ensure that resources are allocated according to military doctrine. Using information about the desired content, channelization identifies opportunities to aggregate users onto shared channels reducing redundant transmissions. Hence, channelization increases the information throughput of the system and balances sender/receiver processing load.

  8. Real time visual servoing using controlled illumination

    NASA Astrophysics Data System (ADS)

    Urban, J. P.; Motyl, G.; Gallice, J.

    1994-02-01

    A real-time visual servoing approach is applied to robotics tasks consisting of the positioning of the end effector with respect to a priori known polyhedral objects. The vision apparatus is consituted by a compact CCD camera rigidly coupled with two laser stripes mounted on the wrist of a robot manipulator. The objective is to servo the robot and effector at a constant position and orientation with respect to a known object in three- dimensional space in the field of view of the sensory system. The approach is expressed in terms of sensor-based control applied to visual servoing. In the case of camera-light stripe coupling, the elementary visual signals used for visual servoing are the points of discontinuity in the light stripes. The feasibility of the approach is demonstrated in a factory automation task consisting of the positioning of the end-effector tool over a vehicle battery. Both simulation and experimentation results are presented, proving the robustness and stability of the algorithm.

  9. Ames Lab 101: Real-Time 3D Imaging

    ScienceCinema

    Zhang, Song

    2016-07-12

    Ames Laboratory scientist Song Zhang explains his real-time 3-D imaging technology. The technique can be used to create high-resolution, real-time, precise, 3-D images for use in healthcare, security, and entertainment applications.

  10. Ames Lab 101: Real-Time 3D Imaging

    SciTech Connect

    Zhang, Song

    2010-01-01

    Ames Laboratory scientist Song Zhang explains his real-time 3-D imaging technology. The technique can be used to create high-resolution, real-time, precise, 3-D images for use in healthcare, security, and entertainment applications.

  11. Real time reconstruction of quasiperiodic multi parameter physiological signals

    NASA Astrophysics Data System (ADS)

    Ganeshapillai, Gartheeban; Guttag, John

    2012-12-01

    A modern intensive care unit (ICU) has automated analysis systems that depend on continuous uninterrupted real time monitoring of physiological signals such as electrocardiogram (ECG), arterial blood pressure (ABP), and photo-plethysmogram (PPG). These signals are often corrupted by noise, artifacts, and missing data. We present an automated learning framework for real time reconstruction of corrupted multi-parameter nonstationary quasiperiodic physiological signals. The key idea is to learn a patient-specific model of the relationships between signals, and then reconstruct corrupted segments using the information available in correlated signals. We evaluated our method on MIT-BIH arrhythmia data, a two-channel ECG dataset with many clinically significant arrhythmias, and on the CinC challenge 2010 data, a multi-parameter dataset containing ECG, ABP, and PPG. For each, we evaluated both the residual distance between the original signals and the reconstructed signals, and the performance of a heartbeat classifier on a reconstructed ECG signal. At an SNR of 0 dB, the average residual distance on the CinC data was roughly 3% of the energy in the signal, and on the arrhythmia database it was roughly 16%. The difference is attributable to the large amount of diversity in the arrhythmia database. Remarkably, despite the relatively high residual difference, the classification accuracy on the arrhythmia database was still 98%, indicating that our method restored the physiologically important aspects of the signal.

  12. Advanced clinical monitoring: considerations for real-time hemodynamic diagnostics.

    PubMed

    Goldman, J M; Cordova, M J

    1994-01-01

    In an effort to ease staffing burdens and potentially improve patient outcome in an intensive care unit (ICU) environment, we are developing a real-time system to accurately and efficiently diagnose cardiopulmonary emergencies. The system is being designed to utilize all relevant routinely-monitored physiological data in order to automatically diagnose potentially fatal events. The initial stage of this project involved formulating the overall system design and appropriate methods for real-time data acquisition, data storage, data trending, waveform analysis, and implementing diagnostic rules. Initially, we defined a conceptual analysis of the minimum physiologic data set, and the monitoring time-frames (trends) which would be required to diagnose cardiopulmonary emergencies. Following that analysis, we used a fuzzy logic diagnostic engine to analyze physiological data during a simulated arrhythmic cardiac arrest (ACA) in order to assess the validity of our diagnostic methodology. We used rate, trend, and morphologic data extracted from the following signals: expired CO2 time-concentration curve (capnogram), electrocardiogram, and arterial blood pressure. The system performed well: The fuzzy logic engine effectively diagnosed the likelihood of ACA from the subtle hemodynamic trends which preceded the complete arrest. As the clinical picture worsened, the fuzzy logic-based system accurately indicated the change in patient condition. Termination of the simulated arrest was rapidly detected by the diagnostic engine. In view of the effectiveness of this fuzzy logic implementation, we plan to develop additional fuzzy logic modules to diagnose other cardiopulmonary emergencies.

  13. Real-time support for high performance aircraft operation

    NASA Technical Reports Server (NTRS)

    Vidal, Jacques J.

    1989-01-01

    The feasibility of real-time processing schemes using artificial neural networks (ANNs) is investigated. A rationale for digital neural nets is presented and a general processor architecture for control applications is illustrated. Research results on ANN structures for real-time applications are given. Research results on ANN algorithms for real-time control are also shown.

  14. Apparatus Characterizes Transient Voltages in Real Time

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro

    2005-01-01

    is received, a volatile memory is filled with data for a total time of 200 ms. After the data are transferred to nonvolatile memory, the recorder rearms itself within 400 ms to enable recording of subsequent transients. Unfortunately, the recorded data must be retrieved through a serial communication link. Depending on the amount of data recorded, the memory can be filled before retrieval is completed. Although large amounts of data are recorded and retrieved, only a small part of the information (the selected parameters) is usually required. The present transient-voltage recorder provides the required information, without incurring the overhead associated with the recording, storage, and retrieval of complete transient-waveform data. In operation, this apparatus processes transient voltage waveforms in real time to extract and record the selected parameters. An analog-to-digital converter that operates at a speed of as much as 100 mega-samples per second is used to sample a transient waveform. A real-time comparator and peak detector are implemented by use of fast field-programmable gate arrays.

  15. Public Science with Real-Time Experiments

    NASA Astrophysics Data System (ADS)

    Lenardic, A.

    2013-12-01

    One of the best ways for professional scientists to engage in public outreach is to get outside of the university and/or lab walls and go out into the public. That is, go to public spaces to do some science experiments with the public - this includes students of all ages that constitute that public. Technological advance in portable measurement gear now allow one to do real, or near real, time experiments in outdoor, public spaces. We have been running a meta-experiment of this sort, aimed at the public display of science, for about a year now in Houston TX at the Lee and Joe Jamail Skatepark. The project goes under the title of Sk8Lab Houston and has introduced students of all ages to the power of scientific experimentation. We bring a portable science pack with us to the park. The pack has a range of wireless measurement gear that allow experiments to be done on the spot. Some of the experiments are designed by us but many are designed on by whoever suggests them to us that day. Over time the Sk8Lab scientists have built up a level of "trust" with the people who frequent the park (no one feels like we are gonna grade them at the park and they know that the learning is not on some regimented clock). This has broken down some learning walls and allowed for a more informal mode of exploration and a more genuine mode of experimentation (as compared to what often happens in class labs when students feel like they are just being forced to reproduce some known result). We will describe some of the test case experiments we have run and also discuss some of the trials, tribulations, and happy successes (many unplanned) along the way.

  16. Real-Time Feature Tracking Using Homography

    NASA Technical Reports Server (NTRS)

    Clouse, Daniel S.; Cheng, Yang; Ansar, Adnan I.; Trotz, David C.; Padgett, Curtis W.

    2010-01-01

    This software finds feature point correspondences in sequences of images. It is designed for feature matching in aerial imagery. Feature matching is a fundamental step in a number of important image processing operations: calibrating the cameras in a camera array, stabilizing images in aerial movies, geo-registration of images, and generating high-fidelity surface maps from aerial movies. The method uses a Shi-Tomasi corner detector and normalized cross-correlation. This process is likely to result in the production of some mismatches. The feature set is cleaned up using the assumption that there is a large planar patch visible in both images. At high altitude, this assumption is often reasonable. A mathematical transformation, called an homography, is developed that allows us to predict the position in image 2 of any point on the plane in image 1. Any feature pair that is inconsistent with the homography is thrown out. The output of the process is a set of feature pairs, and the homography. The algorithms in this innovation are well known, but the new implementation improves the process in several ways. It runs in real-time at 2 Hz on 64-megapixel imagery. The new Shi-Tomasi corner detector tries to produce the requested number of features by automatically adjusting the minimum distance between found features. The homography-finding code now uses an implementation of the RANSAC algorithm that adjusts the number of iterations automatically to achieve a pre-set probability of missing a set of inliers. The new interface allows the caller to pass in a set of predetermined points in one of the images. This allows the ability to track the same set of points through multiple frames.

  17. Toward Real Time Neural Net Flight Controllers

    NASA Technical Reports Server (NTRS)

    Jorgensen, C. C.; Mah, R. W.; Ross, J.; Lu, Henry, Jr. (Technical Monitor)

    1994-01-01

    NASA Ames Research Center has an ongoing program in neural network control technology targeted toward real time flight demonstrations using a modified F-15 which permits direct inner loop control of actuators, rapid switching between alternative control designs, and substitutable processors. An important part of this program is the ACTIVE flight project which is examining the feasibility of using neural networks in the design, control, and system identification of new aircraft prototypes. This paper discusses two research applications initiated with this objective in mind: utilization of neural networks for wind tunnel aircraft model identification and rapid learning algorithms for on line reconfiguration and control. The first application involves the identification of aerodynamic flight characteristics from analysis of wind tunnel test data. This identification is important in the early stages of aircraft design because complete specification of control architecture's may not be possible even though concept models at varying scales are available for aerodynamic wind tunnel testing. Testing of this type is often a long and expensive process involving measurement of aircraft lift, drag, and moment of inertia at varying angles of attack and control surface configurations. This information in turn can be used in the design of the flight control systems by applying the derived lookup tables to generate piece wise linearized controllers. Thus, reduced costs in tunnel test times and the rapid transfer of wind tunnel insights into prototype controllers becomes an important factor in more efficient generation and testing of new flight systems. NASA Ames Research Center is successfully applying modular neural networks as one way of anticipating small scale aircraft model performances prior to testing, thus reducing the number of in tunnel test hours and potentially, the number of intermediate scaled models required for estimation of surface flow effects.

  18. Real time monitoring of electroless nickel plating

    NASA Astrophysics Data System (ADS)

    Rains, Aaron E.; Kline, Ronald A.

    2013-01-01

    This work deals with the design and manufacturing of the heat and chemical resistant transducer case required for on-line immersion testing, experimental design, data acquisition and signal processing. Results are presented for several depositions with an accuracy of two ten-thousandths of an inch in coating thickness obtained. Monitoring the deposition rate of Electroless Nickel (EN) plating in-situ will provide measurement of the accurate dimensions of the component being plated, in real time. EN is used as for corrosion and wear protection for automotive an - Electroless Nickel (EN) plating is commonly used for corrosion and wear protection for automotive and aerospace components. It plates evenly and symmetrically, theoretically allowing the part to be plated to its final dimension. Currently the standard approach to monitoring the thickness of the deposited nickel is to remove the component from the plating bath and physically measure the part. This can lead to plating problems such as pitting, non-adhesion of the deposit and contamination of the plating solution. The goal of this research effort is to demonstrate that plating thickness can be rapidly and accurately measured using ultrasonic testing. Here a special housing is designed to allow immersion of the ultrasonic transducers directly into the plating bath. An FFT based signal processing algorithm was developed to resolve closely spaced echoes for precise thickness determination. The technique in this research effort was found to be capable of measuring plating thicknesses to within 0.0002 inches. It is expected that this approach will lead to cost savings in many EN plating operations.

  19. A real-time prediction of UTC

    NASA Technical Reports Server (NTRS)

    Thomas, Claudine; Allan, David W.

    1994-01-01

    The reference time scale for all scientific and technologic applications on the Earth, the Universal Coordinated Time (UTC), must be as stable, reliable, and accurate as possible. With this in view the BIPM and before it the BIH, have always calculated and then disseminated UTC with a delay of about 80 days. There are three fundamental reasons for doing this: (1) It takes some weeks for data, gathered from some 200 clocks spread world-wide, to be collected and for errors to be eliminated; (2) changes in clock rates can only be measured with high precision well after the fact; and (3) the measurement noise originating in time links, in particular using Loran-C, is smoothed out only when averaging over an extended period. Until mid-1992, the ultimate stability of UTC was reached at averaging times of about 100 days and corresponded to an Allan deviation sigma(sub y)(tau) of about 1,5x10(exp -14) then compared to the best primary clock in the world, the PTB CS2. For several years now, a predicted UTC has been computed by the USNO through an extrapolation of the values as published in deferred time by the BIPM. This is made available through the USNO Series 4, through the USNO Automated Data Service, and through GPS signals. Due to the instability of UTC, the poor predictability of the available clocks, and the intentional SA degradation of GPS signals, the real-time access to this extrapolated UTC has represented the true deferred-time UTC only to within several hundreds of nanoseconds.

  20. Real time PV manufacturing diagnostic system

    SciTech Connect

    Kochergin, Vladimir; Crawford, Michael A.

    2015-09-01

    The main obstacle Photovoltaic (PV) industry is facing at present is the higher cost of PV energy compared to that of fossil energy. While solar cell efficiencies continue to make incremental gains these improvements are so far insufficient to drive PV costs down to match that of fossil energy. Improved in-line diagnostics however, has the potential to significantly increase the productivity and reduce cost by improving the yield of the process. On this Phase I/Phase II SBIR project MicroXact developed and demonstrated at CIGS pilot manufacturing line a high-throughput in-line PV manufacturing diagnostic system, which was verified to provide fast and accurate data on the spatial uniformity of thickness, an composition of the thin films comprising the solar cell as the solar cell is processed reel-to-reel. In Phase II project MicroXact developed a stand-alone system prototype and demonstrated the following technical characteristics: 1) ability of real time defect/composition inconsistency detection over 60cm wide web at web speeds up to 3m/minute; 2) Better than 1mm spatial resolution on 60cm wide web; 3) an average better than 20nm spectral resolution resulting in more than sufficient sensitivity to composition imperfections (copper-rich and copper-poor regions were detected). The system was verified to be high vacuum compatible. Phase II results completely validated both technical and economic feasibility of the proposed concept. MicroXact’s solution is an enabling technique for in-line PV manufacturing diagnostics to increase the productivity of PV manufacturing lines and reduce the cost of solar energy, thus reducing the US dependency on foreign oil while simultaneously reducing emission of greenhouse gasses.

  1. Practical Real-Time Imaging Stereo Matcher

    NASA Astrophysics Data System (ADS)

    Nishihara, H. K.

    1984-10-01

    A binocular-stereo-matching algorithm for making rapid visual range measurements in noisy images is described. This technique is developed for application to problems in robotics where noise tolerance, reliability, and speed are predominant issues. A high speed pipelined convolver for preprocessing images and an unstructured light technique for improving signal quality are introduced to help enhance performance to meet the demands of this task domain. These optimizations, however, are not sufficient. A closer examination of the problems encountered suggests that broader interpretations of both the objective of binocular stereo and of the zero-crossing theory of Marr and Poggio [Proc. R. Soc. Lond. B 204, 301 (1979)] are required. In this paper, we restrict ourselves to the problem of making a single primitive surface measurement for example, to determine whether or not a specified volume of space is occupied, to measure the range to a surface at an indicated image location, or to determine the elevation gradient at that position. In this framework we make a subtle but important shift from the explicit use of zero-crossing contours (in bandpass-filtered images) as the elements matched between left and right images, to the use of the signs between zero crossings. With this change, we obtain a simpler algorithm with a reduced sensitivity to noise and a more predictable behavior. The practical real-time imaging stereo matcher (PRISM) system incorporates this algorithm with the unstructured light technique and a high speed digital convolver. It has been used successfully by others as a sensor in a path-planning system and a bin-picking system.

  2. Six-month comparison of bimatoprost once-daily and twice-daily with timolol twice-daily in patients with elevated intraocular pressure.

    PubMed

    Sherwood, M; Brandt, J

    2001-05-01

    The efficacy and safety of bimatoprost, a member of a new class of pharmacological agents called prostamides, were compared with the efficacy and safety of timolol in patients with glaucoma or ocular hypertension. Pooled 6-month results from two ongoing, multicenter, randomized, double-masked, clinical trials were analyzed. Patients were randomized in a 2:2:1 ratio to treatment with bimatoprost 0.03% once a day ([QD] n = 474), bimatoprost 0.03% twice a day ([BID] n = 483), or timolol 0.5% BID (n = 241). Scheduled visits were at prestudy, baseline, week 2, week 6, month 3, and month 6. The primary outcome measure was in diurnal intraocular pressure ([IOP] 8 AM, 10 AM, 4 PM, 8 PM). Bimatoprost QD provided significantly greater mean IOP reductions from baseline than timolol at every time of the day and at each study visit (p pressures were achieved by a significantly higher percentage of patients in the bimatoprost QD group than in the timolol group. At 10 AM (peak timolol effect) at month 6, IOP

  3. Characterizing intraocular tumors with photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Xu, Guan; Xue, Yafang; Gursel, Zeynep; Slimani, Naziha; Wang, Xueding; Demirci, Hakan

    2016-03-01

    Intraocular tumors are life-threatening conditions. Long-term mortality from uveal melanoma, which accounts for 80% of primary intraocular tumors, could be as high as 25% depending on the size, ciliary body involvement and extraocular extension. The treatments of intraocular tumors include eye-sparing approaches such as radiotherapy and thermotherapy, and the more aggressive enucleation. The accurate diagnosis of intraocular tumors is thereby critical in the management and follow-up of the patients. The diagnosis of intraocular tumors is usually based on clinical examination with acoustic backscattering based ultrasonography. By analyzing the high frequency fluctuations within the ultrasound (US) signals, microarchitecture information inside the tumor can be characterized. However, US cannot interrogate the histochemical components formulating the microarchitecture. One representative example is the inability of US imaging (and other contemporary imaging modalities as well) in differentiating nevoid and melanoma cells as the two types of cells possesses similar acoustic backscattering properties. Combining optical and US imaging, photoacoustic (PA) measurements encode both the microarchitecture and histochemical component information in biological tissue. This study attempts to characterize ocular tumors by analyzing the high frequency signal components in the multispectral PA images. Ex vivo human eye globes with melanoma and retinoblastoma tumors were scanned using less than 6 mJ per square centimeters laser energy with tunable range of 600-1700 nm. A PA-US parallel imaging system with US probes CL15-7 and L22-14 were used to acquire the high frequency PA signals in real time. Preliminary results show that the proposed method can identify uveal melanoma against retinoblastoma tumors.

  4. Real-Time Payload Operations on the International Space Station

    NASA Technical Reports Server (NTRS)

    Cissom, Rick D.; Watson, Kristi

    2004-01-01

    This paper will focus on the challenges that Payload Operations have faced as Payload Utilization has evolved over the last three years of real-time experience. Specifically the paper will focus on the planning challenges and the constant battle over program allocation between core systems and payloads, the process of developing and implementing crew training in a centralized location that is being support by a payload development community spread out all over the US, the unique challenges associated with deployed pressurized payload payloads that are not located within an ISPR, and the importance of documenting specific requirements that the payload development community must implement to get through the crew reviews associated with training and procedures. The authors will focus on specific lessons learned and improvements that have been made in both the streamlining of the processes and the associated documentation.

  5. Simulation of MC-1 Engine on Real-Time Station

    NASA Technical Reports Server (NTRS)

    Ly, William; Roe, Fred (Technical Monitor)

    2001-01-01

    The MC-1 rocket engine is a new, 60,000-pound-thrust engine designed to boost small spacecraft carrying payloads weighing up to 500 pounds. The engine was designed in-house at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, and built by SUMMA Technology, Inc. A vital part of the success of the engine development was the verification of the Propulsion System Controller (PSC) used to control the MC-1 engine during development testing at test facilities in Mississippi and California. The MC-1 engine simulation software was developed on the Applied Dynamics, Inc.'s Real-Time Station (RTS) computer system (ESL) to verify the PSC's hardware and software performance in the Marshall Avionics System Testbed's (MAST) Engine Simulation Lab at the MSFC. The engine model includes the simulation of pressure transducers, thermocouple sensors and valve-positions.

  6. Satellite clock corrections estimation to accomplish real time ppp: experiments for brazilian real time network

    NASA Astrophysics Data System (ADS)

    Marques, Haroldo; Monico, João; Aquino, Marcio; Melo, Weyller

    2014-05-01

    The real time PPP method requires the availability of real time precise orbits and satellites clocks corrections. Currently, it is possible to apply the solutions of clocks and orbits available by BKG within the context of IGS Pilot project or by using the operational predicted IGU ephemeris. The accuracy of the satellite position available in the IGU is enough for several applications requiring good quality. However, the satellites clocks corrections do not provide enough accuracy (3 ns ~ 0.9 m) to accomplish real time PPP with the same level of accuracy. Therefore, for real time PPP application it is necessary to further research and develop appropriated methodologies for estimating the satellite clock corrections in real time with better accuracy. Currently, it is possible to apply the real time solutions of clocks and orbits available by Federal Agency for Cartography and Geodesy (BKG) within the context of IGS Pilot project. The BKG corrections are disseminated by a new proposed format of the RTCM 3.x and can be applied in the broadcasted orbits and clocks. Some investigations have been proposed for the estimation of the satellite clock corrections using GNSS code and phase observable at the double difference level between satellites and epochs (MERVAT, DOUSA, 2007). Another possibility consists of applying a Kalman Filter in the PPP network mode (HAUSCHILD, 2010) and it is also possible the integration of both methods, using network PPP and observables at double difference level in specific time intervals (ZHANG; LI; GUO, 2010). For this work the methodology adopted consists in the estimation of the satellite clock corrections based on the data adjustment in the PPP mode, but for a network of GNSS stations. The clock solution can be solved by using two types of observables: code smoothed by carrier phase or undifferenced code together with carrier phase. In the former, we estimate receiver clock error; satellite clock correction and troposphere, considering

  7. Instrumentation development for real time brainwave monitoring.

    SciTech Connect

    Anderson, Lawrence Frederick; Clough, Benjamin W.

    2005-12-01

    The human brain functions through a chemically-induced biological process which operates in a manner similar to electrical systems. The signal resulting from this biochemical process can actually be monitored and read using tools and having patterns similar to those found in electrical and electronics engineering. The primary signature of this electrical activity is the ''brain wave'', which looks remarkably similar to the output of many electrical systems. Likewise, the device currently used in medical arenas to read brain electrical activity is the electroencephalogram (EEG) which is synonymous with a multi-channel oscilloscope reading. Brain wave readings and recordings for medical purposes are traditionally taken in clinical settings such as hospitals, laboratories or diagnostic clinics. The signal is captured via externally applied scalp electrodes using semi-viscous gel to reduce impedance. The signal will be in the 10 to 100 microvolt range. In other instances, where surgeons are attempting to isolate particular types of minute brain signals, the electrodes may actually be temporarily implanted in the brain during a preliminary procedure. The current configurations of equipment required for EEGs involve large recording instruments, many electrodes, wires, and large amounts of hard disk space devoted to storing large files of brain wave data which are then eventually analyzed for patterns of concern. Advances in sensors, signal processing, data storage and microelectronics over the last decade would seem to have paved the way for the realization of devices capable of ''real time'' external monitoring, and possible assessment, of brain activity. A myriad of applications for such a capability are likewise presenting themselves, including the ability to assess brain functioning, level of functioning and malfunctioning. Our plan is to develop the sensors, signal processing, and portable instrumentation package which could capture, analyze, and communicate

  8. Real Time Wide Area Radiation Surveillance System

    NASA Astrophysics Data System (ADS)

    Biafore, M.

    2012-04-01

    We present the REWARD project, financed within the FP7 programme, theme SEC-2011.1.5-1 (Development of detection capabilities of difficult to detect radioactive sources and nuclear materials - Capability Project). Within this project, we propose a novel mobile system for real time, wide area radiation surveillance. The system is based on the integration of new miniaturized solid-state radiation sensors: a CdZnTe detector for gamma radiation and a high efficiency neutron detector based on novel silicon technologies. The sensing unit will include a wireless communication interface to send the data remotely to a monitoring base station which also uses a GPS system to calculate the position of the tag. The system will also incorporate middleware and high level software to provide web-service interfaces for the exchange of information, and that will offer top level functionalities as management of users, mobile tags and environment data and alarms, database storage and management and a web-based graphical user interface. Effort will be spent to ensure that the software is modular and re-usable across as many architectural levels as possible. Finally, an expert system will continuously analyze the information from the radiation sensor and correlate it with historical data from the tag location in order to generate an alarm when an abnormal situation is detected. The system will be useful for many different scenarios, including such lost radioactive sources and radioactive contamination. It will be possible to deploy in emergency units and in general in any type of mobile or static equipment. The sensing units will be highly portable thanks to their low size and low energy consumption. The complete system will be scalable in terms of complexity and cost and will offer very high precision on both the measurement and the location of the radiation. The modularity and flexibility of the system will allow for a realistic introduction to the market. Authorities may start with a

  9. Real-time Forensic Disaster Analysis

    NASA Astrophysics Data System (ADS)

    Wenzel, F.; Daniell, J.; Khazai, B.; Mühr, B.; Kunz-Plapp, T.; Markus, M.; Vervaeck, A.

    2012-04-01

    The Center for Disaster Management and Risk Reduction Technology (CEDIM, www.cedim.de) - an interdisciplinary research center founded by the German Research Centre for Geoscience (GFZ) and Karlsruhe Institute of Technology (KIT) - has embarked on a new style of disaster research known as Forensic Disaster Analysis. The notion has been coined by the Integrated Research on Disaster Risk initiative (IRDR, www.irdrinternational.org) launched by ICSU in 2010. It has been defined as an approach to studying natural disasters that aims at uncovering the root causes of disasters through in-depth investigations that go beyond the reconnaissance reports and case studies typically conducted after disasters. In adopting this comprehensive understanding of disasters CEDIM adds a real-time component to the assessment and evaluation process. By comprehensive we mean that most if not all relevant aspects of disasters are considered and jointly analysed. This includes the impact (human, economy, and infrastructure), comparisons with recent historic events, social vulnerability, reconstruction and long-term impacts on livelihood issues. The forensic disaster analysis research mode is thus best characterized as "event-based research" through systematic investigation of critical issues arising after a disaster across various inter-related areas. The forensic approach requires (a) availability of global data bases regarding previous earthquake losses, socio-economic parameters, building stock information, etc.; (b) leveraging platforms such as the EERI clearing house, relief-web, and the many sources of local and international sources where information is organized; and (c) rapid access to critical information (e.g., crowd sourcing techniques) to improve our understanding of the complex dynamics of disasters. The main scientific questions being addressed are: What are critical factors that control loss of life, of infrastructure, and for economy? What are the critical interactions

  10. Efficacy and Tolerability of the Fixed Combinations Latanoprost/Timolol versus Dorzolamide/Timolol in Patients with Elevated Intraocular Pressure: A Meta-Analysis of Randomized Controlled Trials

    PubMed Central

    Huang, Wenyong

    2013-01-01

    Objective To evaluate the efficacy and tolerability of the fixed combination of Latanoprost/Timolol versus Dorzolamide/Timolol in the treatment of patients with elevated intraocular pressure (IOP). Methods A comprehensive literature meta-analysis was performed according to the Cochrane Collaboration methodology to identify randomized clinical trials comparing latanoprost/timolol FC (FCLT) with dorzolamide/timolol (FCDT) in patients with elevated IOP. The efficacy estimates were measured by the weight mean difference (WMD) for the IOP reduction (IOPR) from baseline to end point, including the diurnal mean IOPR, 8 AM IOPR, 12 PM IOPR, and 4 PM IOPR. The tolerability estimates were measured by RR for adverse events. All outcomes were reported with a 95% confidence interval (CI). The data were synthesized by Stata 12.0 SE for Windows. Results Eight studies involving 841 patients (841 eyes) were included in the meta-analysis. With a WMD of IOPR in the diurnal mean of 0.16 mmHg (95% CI, -0.31 to 0.63), the FCLT was as effective as FCDT in lowering IOP in patients with elevated IOP (P = 0.51). The WMDs of IOPR were 0.58 mmHg (95% CI: -0.002 to 1.17) at 8 AM, -0.07 mmHg (95% CI: -0.50 to 0.36) at 12 PM, and 0.41 mmHg (95% CI: -0.18 to 1.00) at 4 PM, and there were no significant difference between FCLT and FCDT. FCLT was associated with a significantly lower incidence of eye pain, bitter taste, and irritation/stinging than FCDT, with pooled RRs of 0.34 (95% CI: 0.14 to 0.82), 0.06 (95% CI:0.008 to 0.42), and 0.35 (95% CI: 0.14 to 0.85), respectively. Conclusion FCLT was associated with equivalent efficacy in IOP lowering comparing with FCDT. However, FCLT was better tolerated than FCDT. PMID:24349536

  11. Protein expression, biochemical pharmacology of signal transduction, and relation to intraocular pressure modulation by bradykinin B2 receptors in ciliary muscle

    PubMed Central

    Xu, Shouxi; Li, Linya; Katoli, Parvaneh; Kelly, Curtis R.; Wang, Yu; Cao, Shutong; Patil, Rajkumar; Husain, Shahid; Klekar, Laura; Scott, Daniel

    2013-01-01

    Purpose To examine the bradykinin (BK) B2-receptor system in human and monkey ciliary muscle (CM) using immunohistochemical techniques, and to pharmacologically characterize the associated biochemical signal transduction systems in human CM (h-CM) cells. BK-induced modulation of intraocular pressure (IOP) in pigmented Dutch-Belt rabbits and cynomolgus monkeys was also studied. Methods Previously published procedures were used throughout these studies. Results The human and monkey ciliary bodies expressed high levels of B2-receptor protein immunoreactivity. Various kinins differentially stimulated [Ca2+]i mobilization in primary h-CM cells (BK EC50=2.4±0.2 nM > Hyp3,β-(2-thienyl)-Ala5,Tyr(Me)8-(®)-Arg9)-BK (RMP-7) > Des-Arg9-BK EC50=4.2 µM [n=3–6]), and this was blocked by B2-selective antagonists, HOE-140 (IC50=1.4±0.1 nM) and WIN-63448 (IC50=174 nM). A phospholipase C inhibitor (U73122; 10–30 µM) and ethylene glycol tetraacetic acid (1–2 mM) abolished the BK-induced [Ca2+]i mobilization. Total prostaglandin (primarily PGE2) secretion stimulated by BK and other kinins in h-CM cells was attenuated by the cyclooxygenase inhibitors bromfenac and flurbiprofen, and by the B2-antagonists. BK and RMP-7 (100 nM) induced a twofold increase in extracellular signal-regulated kinase-1/2 phosphorylation, and BK (0.1–1 µM; at 24 h) caused a 1.4–3.1-fold increase in promatrix metalloproteinases-1–3 release. Topical ocular BK (100 µg) failed to alter IOP in cynomolgus monkeys. However, intravitreal injection of 50 µg of BK, but not Des-Arg9-BK, lowered IOP in rabbit eyes (22.9±7.3% and 37.0±5.6% at 5 h and 8 h post-injection; n=7–10). Conclusions These studies have provided evidence of a functional endogenously expressed B2-receptor system in the CM that appears to be involved in modulating IOP. PMID:23805043

  12. An observational study of bimatoprost 0.01% in patients on prior intraocular pressure-lowering therapy: the Canadian Lumigan® RC Early Analysis Review (CLEAR) trial

    PubMed Central

    Crichton, Andrew C; Nixon, Donald R; Simonyi, Susan; Bhogal, Meetu; Sigouin, Christopher S; Discepola, Marino J; Hutnik, Cindy ML; Baptiste, Darryl C; Yan, David B

    2014-01-01

    Purpose To evaluate the ocular hyperemia and intraocular pressure (IOP)-lowering efficacy of bimatoprost 0.01% in subjects with elevated IOP due to primary open-angle glaucoma (POAG) or ocular hypertension (OHT) in a real-world clinical setting. Subjects and methods This open-label, 12-week, observational study was conducted at 67 centers in Canada. Subjects with elevated IOP due to POAG or OHT instilled bimatoprost 0.01% as monotherapy once daily. Ocular hyperemia was graded by the investigator at baseline, week 6, and week 12 using a standardized photographic 5-point grading scale. Change in IOP from baseline was also evaluated at these time points. This analysis includes the subgroup of 268 subjects who had been previously treated with latanoprost 0.005%, bimatoprost 0.03%, travoprost 0.004%, and travoprost 0.004% with SofZia™ or nonselective beta-adrenergic receptor blockers prior to the study. Results After 12 weeks of treatment with 0.01% bimatoprost, ocular hyperemia was graded as none-to-mild hyperemia (grades 0, +0.5, or +1) for 94.1% of subjects and as moderate-to-severe hyperemia (grades +2 or +3) for 5.9%. No statistically significant shifts in ocular hyperemia ratings were observed at week 12 for any of the prior IOP-lowering therapies except bimatoprost 0.03%, in which 20.8% of subjects experienced an improvement. The mean percentage change from baseline IOP at week 12 following the switch to bimatoprost 0.01% monotherapy ranged from −2.3%±17.3% to −26.3%±12.4%. Furthermore, the decreased mean percentage change from baseline IOP was statistically significant across all prior IOP-lowering medications, except for bimatoprost 0.03% at the 6- and 12-week visits and travoprost 0.004% at the 6-week visit. Conclusion This observational study demonstrates that bimatoprost 0.01% was well tolerated among POAG and OHT subjects who switched from prior IOP-lowering medication. Furthermore, a switch in ocular hypertensive treatment to bimatoprost 0.01% was

  13. Real time UAV autonomy through offline calculations

    NASA Astrophysics Data System (ADS)

    Jung, Sunghun

    . Once one or several targets are detected, UAVs near the target are manipulated to approach to the target. If the number of detected targets is more than one, UAVs are evenly grouped to track targets. After a specific period of time, UAVs hand off and continue their original tasks. Thirdly, Emergency algorithm is generated to avoid losses of UAVs when UAVs have system failures. If one UAV is out of fuel or control during the mission, the Emergency algorithm brings the malfunctioning UAV to the point of departure and let the rest UAVs to continue an aerial reconnaissance. An UAV which finishes its task the earliest will continue to search a region which the failed UAV is supposed to search. In addition, Emergency algorithm prevents UAVs colliding into each other by using emergency altitude. Overall, the framework developed here facilitates the solution of several mission planning problems. The robustness built into our discretization of space and time permits feedback corrections on real-time to vehicle trajectories. The library of off-line solutions proposed and developed here minimizes computational overhead during operations.

  14. Real Time Flux Control in PM Motors

    SciTech Connect

    Otaduy, P.J.

    2005-09-27

    Significant research at the Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) is being conducted to develop ways to increase (1) torque, (2) speed range, and (3) efficiency of traction electric motors for hybrid electric vehicles (HEV) within existing current and voltage bounds. Current is limited by the inverter semiconductor devices' capability and voltage is limited by the stator wire insulation's ability to withstand the maximum back-electromotive force (emf), which occurs at the upper end of the speed range. One research track has been to explore ways to control the path and magnitude of magnetic flux while the motor is operating. The phrase, real time flux control (RTFC), refers to this mode of operation in which system parameters are changed while the motor is operating to improve its performance and speed range. RTFC has potential to meet an increased torque demand by introducing additional flux through the main air gap from an external source. It can augment the speed range by diverting flux away from the main air gap to reduce back-emf at high speeds. Conventional RTFC technology is known as vector control [1]. Vector control decomposes the stator current into two components; one that produces torque and a second that opposes (weakens) the magnetic field generated by the rotor, thereby requiring more overall stator current and reducing the efficiency. Efficiency can be improved by selecting a RTFC method that reduces the back-emf without increasing the average current. This favors methods that use pulse currents or very low currents to achieve field weakening. Foremost in ORNL's effort to develop flux control is the work of J. S. Hsu. Early research [2,3] introduced direct control of air-gap flux in permanent magnet (PM) machines and demonstrated it with a flux-controlled generator. The configuration eliminates the problem of demagnetization because it diverts all the flux from the magnets instead of

  15. Real-Time Wireless Data Acquisition System

    NASA Technical Reports Server (NTRS)

    Valencia, Emilio J.; Perotti, Jose; Lucena, Angel; Mata, Carlos

    2007-01-01

    Current and future aerospace requirements demand the creation of a new breed of sensing devices, with emphasis on reduced weight, power consumption, and physical size. This new generation of sensors must possess a high degree of intelligence to provide critical data efficiently and in real-time. Intelligence will include self-calibration, self-health assessment, and pre-processing of raw data at the sensor level. Most of these features are already incorporated in the Wireless Sensors Network (SensorNet(TradeMark)), developed by the Instrumentation Group at Kennedy Space Center (KSC). A system based on the SensorNet(TradeMark) architecture consists of data collection point(s) called Central Stations (CS) and intelligent sensors called Remote Stations (RS) where one or more CSs can be accommodated depending on the specific application. The CS's major function is to establish communications with the Remote Stations and to poll each RS for data and health information. The CS also collects, stores and distributes these data to the appropriate systems requiring the information. The system has the ability to perform point-to-point, multi-point and relay mode communications with an autonomous self-diagnosis of each communications link. Upon detection of a communication failure, the system automatically reconfigures to establish new communication paths. These communication paths are automatically and autonomously selected as the best paths by the system based on the existing operating environment. The data acquisition system currently under development at KSC consists of the SensorNet(TradeMark) wireless sensors as the remote stations and the central station called the Radio Frequency Health Node (RFHN). The RFF1N is the central station which remotely communicates with the SensorNet(TradeMark) sensors to control them and to receive data. The system's salient feature is the ability to provide deterministic sensor data with accurate time stamps for both time critical and non

  16. Association Between Cardiovascular and Intraocular Pressure Changes in a 14-Day 6 deg Head Down Tilt (HDT) Bed Rest Study: Possible Implications in Retinal Anatomy

    NASA Technical Reports Server (NTRS)

    Cromwell, Ronita; Zanello, Susana; Yarbough, Patrice; Ploutz-Snyder, Robert; Taibbi, Giovanni; Vizzeri, Gianmarco

    2013-01-01

    Visual symptoms and intracranial pressure increase reported in astronauts returning from long duration missions in low Earth-orbit are thought to be related to fluid shifts within the body due to microgravity exposure. Because of this possible relation to fluid shifts, studies conducted in head-down tilt (HDT) bed rest are being monitored for potential changes in ocular health. These measures will also serve to determine whether HDT is a suitable ground-based analog to model subclinical cardiovascular and ocular changes that could shed light on the etiology of the VIIP syndrome observed in spaceflight. Sixteen healthy normotensive (12M, 4F, age range 29-54 years), non-smoker and normal weight subjects, volunteered to participate in a 14 day 6 deg head HDT study conducted at the NASA Flight Analogs Research Unit (FARU). This facility provides standard bed rest conditions (diet, wake/sleep time, time allowed in sunlight) during the time that the subjects stay at the FARU. Cardiovascular parameters were obtained in supine posture at BR-5, BR+0, and BR+3 and ocular monitoring was performed weekly. Intraocular pressure (IOP) increased from pre-bed rest BR-3) to the third day into bed rest (BR+3). Values reached a plateau towards the end of the bed rest phase (BR10) and decreased within the first three days of recovery (BR+2) returning to levels comparable to baseline at BR-3. As expected, most cardiovascular parameters were affected by 14 days of HDT bed rest. Plasma volume decreased as a result of bed rest but recovered to baseline levels by BR+3. Indications of cardiovascular deconditioning included increase in both systolic and diastolic blood pressure and heart rate, and a decrease in stroke volume and cardiac output between BR-5 and BR+3. Due to the experimental design of this study, we were not able to test the hypothesis that fluid shifts might be involved in the IOP increase during the bed rest phase, since cardiovascular measures were not available for those

  17. A Novel, Real-Time, In Vivo Mouse Retinal Imaging System

    PubMed Central

    Butler, Mark C.; Sullivan, Jack M.

    2015-01-01

    Purpose To develop an efficient, low-cost instrument for robust real-time imaging of the mouse retina in vivo, and assess system capabilities by evaluating various animal models. Methods Following multiple disappointing attempts to visualize the mouse retina during a subretinal injection using commercially available systems, we identified the key limitation to be inadequate illumination due to off axis illumination and poor optical train optimization. Therefore, we designed a paraxial illumination system for Greenough-type stereo dissecting microscope incorporating an optimized optical launch and an efficiently coupled fiber optic delivery system. Excitation and emission filters control spectral bandwidth. A color coupled-charged device (CCD) camera is coupled to the microscope for image capture. Although, field of view (FOV) is constrained by the small pupil aperture, the high optical power of the mouse eye, and the long working distance (needed for surgical manipulations), these limitations can be compensated by eye positioning in order to observe the entire retina. Results The retinal imaging system delivers an adjustable narrow beam to the dilated pupil with minimal vignetting. The optic nerve, vasculature, and posterior pole are crisply visualized and the entire retina can be observed through eye positioning. Normal and degenerative retinal phenotypes can be followed over time. Subretinal or intraocular injection procedures are followed in real time. Real-time, intravenous fluorescein angiography for the live mouse has been achieved. Conclusions A novel device is established for real-time viewing and image capture of the small animal retina during subretinal injections for preclinical gene therapy studies. PMID:26551329

  18. Easy and hard testbeds for real-time search algorithms

    SciTech Connect

    Koenig, S.; Simmons, R.G.

    1996-12-31

    Although researchers have studied which factors influence the behavior of traditional search algorithms, currently not much is known about how domain properties influence the performance of real-time search algorithms. In this paper we demonstrate, both theoretically and experimentally, that Eulerian state spaces (a super set of undirected state spaces) are very easy for some existing real-time search algorithms to solve: even real-time search algorithms that can be intractable, in general, are efficient for Eulerian state spaces. Because traditional real-time search testbeds (such as the eight puzzle and gridworlds) are Eulerian, they cannot be used to distinguish between efficient and inefficient real-time search algorithms. It follows that one has to use non-Eulerian domains to demonstrate the general superiority of a given algorithm. To this end, we present two classes of hard-to-search state spaces and demonstrate the performance of various real-time search algorithms on them.

  19. Mechatronic objects for real-time control software development

    NASA Astrophysics Data System (ADS)

    Muir, Patrick F.; Horner, Jeremy W.

    1998-12-01

    The design of real-time control software for a mechatronic system must be effectively integrated with the system hardware in order to achieve useful qualitative benefits beyond basic functionality. The sought-after benefits include: rapid development, flexibility, maintainability, extensively, and reusability. In this work we focus upon the interface between the device drivers and the control software with the aim to properly design this interface to best realize the aforementioned benefits. The results of this fundamental research include the development of an easily manageable set of four C++ object classes following an object-oriented approach to software design. These Universal Mechatronic Objects (UMOs) are applicable to a wide spectrum of actuators including dc motors, stepper motors, and solenoids; and sensors including pressure sensors, microswitches, and encoders. UMOs encapsulate the interface between the electrical subsystem and the control subsystem, providing the control software developer with a powerful abstraction that facilitates the development of hardware-independent control code and providing the electrical subsystem developer with an effective abstraction that facilitates the development of application-independent device drivers. Objects which are intuitively related to hardware components of the mechatronic system can be declared using the UMOs early in the system development process to facilitate the rapid concurrent development of both the electrical and the control subsystems. Our UMOs were developed as part of a project to implement a real-time control system for a z-theta robotic manipulator. The z- theta manipulator is one component of the Minifactory project in the Microdynamic Systems Laboratory at Carnegie Mellon University. The goals of this agile assembly project include the reduction of factory setup and changeover times, plug-and-play type modularity, and the reuse of its components. The application of UMOs to the manipulator

  20. PERTS: A Prototyping Environment for Real-Time Systems

    NASA Technical Reports Server (NTRS)

    Liu, Jane W. S.; Lin, Kwei-Jay; Liu, C. L.

    1993-01-01

    PERTS is a prototyping environment for real-time systems. It is being built incrementally and will contain basic building blocks of operating systems for time-critical applications, tools, and performance models for the analysis, evaluation and measurement of real-time systems and a simulation/emulation environment. It is designed to support the use and evaluation of new design approaches, experimentations with alternative system building blocks, and the analysis and performance profiling of prototype real-time systems.