A Relationship Between Constraint and the Critical Crack Tip Opening Angle

NASA Technical Reports Server (NTRS)

Johnston, William M.; James, Mark A.

2009-01-01

Of the various approaches used to model and predict fracture, the Crack Tip Opening Angle (CTOA) fracture criterion has been successfully used for a wide range of two-dimensional thin-sheet and thin plate applications. As thicker structure is considered, modeling the full three-dimensional fracture process will become essential. This paper investigates relationships between the local CTOA evaluated along a three-dimensional crack front and the corresponding local constraint. Previously reported tunneling crack front shapes were measured during fracture by pausing each test and fatigue cycling the specimens to mark the crack surface. Finite element analyses were run to model the tunneling shape during fracture, with the analysis loading conditions duplicating those tests. The results show an inverse relationship between the critical fracture value and constraint which is valid both before maximum load and after maximum load.

Large-Scale Noniridescent Structural Color Printing Enabled by Infiltration-Driven Nonequilibrium Colloidal Assembly.

PubMed

Bai, Ling; Mai, Van Cuong; Lim, Yun; Hou, Shuai; Möhwald, Helmuth; Duan, Hongwei

2018-03-01

Structural colors originating from interaction of light with intricately arranged micro-/nanostructures have stimulated considerable interest because of their inherent photostability and energy efficiency. In particular, noniridescent structural color with wide viewing angle has been receiving increasing attention recently. However, no method is yet available for rapid and large-scale fabrication of full-spectrum structural color patterns with wide viewing angles. Here, infiltration-driven nonequilibrium assembly of colloidal particles on liquid-permeable and particle-excluding substrates is demonstrated to direct the particles to form amorphous colloidal arrays (ACAs) within milliseconds. The infiltration-assisted (IFAST) colloidal assembly opens new possibilities for rapid manufacture of noniridescent structural colors of ACAs and straightforward structural color mixing. Full-spectrum noniridescent structural colors are successfully produced by mixing primary structural colors of red, blue, and yellow using a commercial office inkjet printer. Rapid fabrication of large-scale structural color patterns with sophisticated color combination/layout by IFAST printing is realized. The IFAST technology is versatile for developing structural color patterns with wide viewing angles, as colloidal particles, inks, and substrates are flexibly designable for diverse applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of blotchy pigments in the anterior chamber angle as a sign of angle closure

PubMed Central

Rao, Harsha L; Mungale, Sachin C; Kumbar, Tukaram; Parikh, Rajul S; Garudadri, Chandra S

2012-01-01

Background: Blotchy pigments in the anterior chamber (AC) angle are considered diagnostic of primary angle closure (PAC). But there are no reports either on the prevalence of blotchy pigments in AC angles or the validity of this sign. Aims: To determine the prevalence of blotchy pigments in AC angles and to evaluate their relationship with glaucomatous optic neuropathy (GON) in eyes with occludable angles. Setting and Design: Cross-sectional, comparative study. Materials and Methods: Gonioscopy was performed in 1001 eyes of 526 subjects (245 eyes of 148 consecutive, occludable angle subjects and 756 eyes of 378 non-consecutive, open angle subjects), above 35 years of age. Quadrant-wise location of blotchy pigments was documented. Statistical Analysis: Odds of blotchy pigments in occludable angles against that in open angles were evaluated. Relationship of GON with blotchy pigments in occludable angle eyes was evaluated using a multivariate model. Results: Prevalence of blotchy pigments in occludable angles was 28.6% (95% CI, 22.9-34.3) and in open angles was 4.7% (95% CI, 3.2-6.3). Blotchy pigments were more frequently seen in inferior (16%) and superior quadrants (15%) of occludable angles, and inferior quadrant of open angles (4%). Odds of superior quadrant blotchy pigments in occludable angles were 33 times that in open angles. GON was seen in 107 occludable angle eyes. Blotchy pigments were not significantly associated with GON (odds ratio = 0.5; P = 0.1). Conclusions: Blotchy pigments were seen in 28.6% of occludable angle eyes and 4.7% of open angles eyes. Presence of blotchy pigments in the superior quadrant is more common in occludable angles. Presence of GON in occludable angle eyes was not associated with blotchy pigments. PMID:23202393

Wedgethread pipe connection

DOEpatents

Watts, John D.

2003-06-17

Several embodiments of a wedgethread pipe connection are disclosed that have improved makeup, sealing, and non-loosening characteristics. In one embodiment, an open wedgethread is disclosed that has an included angle measured in the gap between the stab flank and the load flank to be not less than zero, so as to prevent premature wedging between mating flanks before the position of full makeup is reached, as does occur between trapped wedgethreads wherein the included angle is less than zero. The invention may be used for pipe threads large or small, as a flush joint, with collars, screwed into plates or it may even be used to reversibly connect such as solid posts to base members where a wide makeup torque range is desired. This Open wedgethread, as opposed to trapped wedgethreads, provides a threaded pipe connection that: is more cost-effective; can seal high pressure gas; can provide selectively a connection strength as high as the pipe strength; assures easy makeup to the desired position of full makeup within a wide torque range; may have a torque strength as high as the pipe torque strength; is easier to manufacture; is easier to gage; and is less subject to handling damage.

A NARROW SHORT-DURATION GRB JET FROM A WIDE CENTRAL ENGINE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duffell, Paul C.; Quataert, Eliot; MacFadyen, Andrew I., E-mail: duffell@berkeley.edu

2015-11-01

We use two-dimensional relativistic hydrodynamic numerical calculations to show that highly collimated relativistic jets can be produced in neutron star merger models of short-duration gamma-ray bursts (GRBs) without the need for a highly directed engine or a large net magnetic flux. Even a hydrodynamic engine generating a very wide sustained outflow on small scales can, in principle, produce a highly collimated relativistic jet, facilitated by a dense surrounding medium that provides a cocoon surrounding the jet core. An oblate geometry to the surrounding gas significantly enhances the collimation process. Previous numerical simulations have shown that the merger of two neutronmore » stars produces an oblate, expanding cloud of dynamical ejecta. We show that this gas can efficiently collimate the central engine power much like the surrounding star does in long-duration GRB models. For typical short-duration GRB central engine parameters, we find jets with opening angles of an order of 10° in which a large fraction of the total outflow power of the central engine resides in highly relativistic material. These results predict large differences in the opening angles of outflows from binary neutron star mergers versus neutron star–black hole mergers.« less

Common variants near CAV1 and CAV2 are associated with primary open-angle glaucoma

PubMed Central

Thorleifsson, Gudmar; Walters, G Bragi; Hewitt, Alex W; Masson, Gisli; Helgason, Agnar; DeWan, Andrew; Sigurdsson, Asgeir; Jonasdottir, Adalbjorg; Gudjonsson, Sigurjon A; Magnusson, Kristinn P; Stefansson, Hreinn; Lam, Dennis S C; Tam, Pancy O S; Gudmundsdottir, Gudrun J; Southgate, Laura; Burdon, Kathryn P; Gottfredsdottir, Maria Soffia; Aldred, Micheala A; Mitchell, Paul; St Clair, David; Collier, David A; Tang, Nelson; Sveinsson, Orn; Macgregor, Stuart; Martin, Nicholas G; Cree, Angela J; Gibson, Jane; MacLeod, Alex; Jacob, Aby; Ennis, Sarah; Young, Terri L; Chan, Juliana C N; Karwatowski, Wojciech S S; Hammond, Christopher J; Thordarson, Kristjan; Zhang, Mingzhi; Wadelius, Claes; Lotery, Andrew J; Trembath, Richard C; Pang, Chi Pui; Hoh, Josephine; Craig, Jamie E; Kong, Augustine; Mackey, David A; Jonasson, Fridbert; Thorsteinsdottir, Unnur; Stefansson, Kari

2011-01-01

We conducted a genome-wide association study for primary open-angle glaucoma (POAG) in 1,263 affected individuals (cases) and 34,877 controls from Iceland. We identified a common sequence variant at 7q31 (rs4236601[A], odds ratio (OR) = 1.36, P = 5.0 × 10-10). We then replicated the association in sample sets of 2,175 POAG cases and 2,064 controls from Sweden, the UK and Australia (combined OR = 1.18, P = 0.0015) and in 299 POAG cases and 580 unaffected controls from Hong Kong and Shantou, China (combined OR = 5.42, P = 0.0021). The risk variant identified here is located close to CAV1 and CAV2, both of which are expressed in the trabecular meshwork and retinal ganglion cells that are involved in the pathogenesis of POAG. PMID:20835238

Glaucoma: Symptoms and Causes

MedlinePlus

... damage. The types of glaucoma include the following: Open-angle glaucoma Open-angle glaucoma is the most common form of ... angle formed by the cornea and iris remains open, but the trabecular meshwork is partially blocked. This ...

Open-angle glaucoma in patients with diabetic retinopathy at the Puerto Rico Medical Center.

PubMed

Cruz-lñigo, Yousef; Izquierdo, Natalio J; García, Omar; Pérez, Raúl

2012-01-01

The association of open-angle glaucoma (OAG) with diabetes mellitus remains controversial. We report on the frequency of open-angle glaucoma in patients having diabetic retinopathy in a population of the Puerto Rico Medical Center. A cross-sectional study of 1,442 patients was done. Only the chart of patients 40 years-of-age and older, with a diagnosis of diabetic retinopathy and/or open-angle glaucoma were included. Descriptive analysis was done. Unadjusted and gender-adjusted logistic regression analyses were used to estimate risk of developing open-angle glaucoma in patients with diabetic retinopathy for each subsequent decade. 1,040 patients were diagnosed with diabetic retinopathy from July 1, 2004 to June 30, 2009. Also, 402 patients were diagnosed with open-angle glaucoma from July 1, 2007 to June 30, 2009. Of the 1,040 patients with diabetic retinopathy, 64 patients (6.15%) also had OAG. According to our gender-adjusted logistic regression analysis the estimated risk of developing open-angle glaucoma for patients 40 years-of-age with diabetic retinopathy increased for each subsequent decade until the seventh decade, odds ratio = 5.07 (95% confidence interval: 1.62-15.86). Thereafter, it decreased, odds ratio = 2.07 (95% confidence interval: 0.36-11.82). Our findings suggest that Puerto Rico patients between 40 to 79 years of age with diabetic retinopathy have an increased risk of developing open-angle glaucoma with each subsequent decade. Screening for open-angle glaucoma in patients with diabetic retinopathy is of utmost importance in the aging Puerto Rico population to prevent blindness.

Experimental demonstration of conformal phased array antenna via transformation optics.

PubMed

Lei, Juan; Yang, Juxing; Chen, Xi; Zhang, Zhiya; Fu, Guang; Hao, Yang

2018-02-28

Transformation Optics has been proven a versatile technique for designing novel electromagnetic devices and it has much wider applicability in many subject areas related to general wave equations. Among them, quasi-conformal transformation optics (QCTO) can be applied to minimize anisotropy of transformed media and has opened up the possibility to the design of broadband antennas with arbitrary geometries. In this work, a wide-angle scanning conformal phased array based on all-dielectric QCTO lens is designed and experimentally demonstrated. Excited by the same current distribution as such in a conventional planar array, the conformal system in presence of QCTO lens can preserve the same radiation characteristics of a planar array with wide-angle beam-scanning and low side lobe level (SLL). Laplace's equation subject to Dirichlet-Neumann boundary conditions is adopted to construct the mapping between the virtual and physical spaces. The isotropic lens with graded refractive index is realized by all-dielectric holey structure after an effective parameter approximation. The measurements of the fabricated system agree well with the simulated results, which demonstrate its excellent wide-angle beam scanning performance. Such demonstration paves the way to a robust but efficient array synthesis, as well as multi-beam and beam forming realization of conformal arrays via transformation optics.

Incident-angle-controlled semitransparent colored perovskite solar cells with improved efficiency exploiting a multilayer dielectric mirror.

PubMed

Lee, Kyu-Tae; Jang, Ji-Yun; Park, Sang Jin; Ok, Song Ah; Park, Hui Joon

2017-09-28

See-through perovskite solar cells with high efficiency and iridescent colors are demonstrated by employing a multilayer dielectric mirror. A certain amount of visible light is used for wide color gamut semitransparent color generation, which can be easily tuned by changing an angle of incidence, and a wide range of visible light is efficiently reflected back toward a photoactive layer of the perovskite solar cells by the dielectric mirror for highly efficient light-harvesting performance, thus achieving 10.12% power conversion efficiency. We also rigorously examine how the number of pairs in the multilayer dielectric mirror affects optical properties of the colored semitransparent perovskite solar cells. The described approach can open the door to a large number of applications such as building-integrated photovoltaics, self-powered wearable electronics and power-generating color filters for energy-efficient display systems.

Evaluation of the anterior chamber angle in Asian Indian eyes by ultrasound biomicroscopy and gonioscopy.

PubMed

Kaushik, Sushmita; Jain, Rajeev; Pandav, Surinder Singh; Gupta, Amod

2006-09-01

To compare the ultrasound biomicroscopic measurement of the anterior chamber angle in Asian Indian eyes, with the angle width estimated by gonioscopy. Patients with open and closed angles attending a glaucoma clinic were recruited for the study. Temporal quadrants of the angles of patients were categorized by gonioscopy as Grade 0 to Grade 4, using Shaffer's classification. These angles were quantified by ultrasound biomicroscopy (UBM) using the following biometric characteristics: Angle opening distance at 250 micro (AOD 250) and 500 micro (AOD 500) from the scleral spur and trabecular meshwork-ciliary process distance (TCPD). The angles were further segregated as "narrow angles" (Schaffer's Grade 2 or less) and "open angles" (Schaffer's Grade 3 and 4). The UBM measurements were computed in each case and analyzed in relation to the gonioscopic angle evaluation. One hundred and sixty three eyes of 163 patients were analyzed. One hundred and six eyes had "narrow angles" and 57 eyes had "open angles" on gonioscopy. There was a significant difference among the mean UBM measurements of each angle grade estimated by gonioscopy (P < 0.001). The Pearson correlation coefficient between all UBM parameters and gonioscopy grades was significant at the 0.01 level. The mean AOD 250, AOD 500 and TCPD in narrow angles were 58+/-49 micro, 102+/-84 micro and 653+/-124 respectively, while it was 176+/-47 micro, 291+/-62 micro and 883+/-94 micro in eyes with open angles (P < 0.001) respectively. The angle width estimated by gonioscopy correlated significantly with the angle dimensions measured by UBM. Gonioscopy, though a subjective test, is a reliable method for estimation of the angle width.

Lamina cribrosa position and Bruch's membrane opening differences between anterior ischemic optic neuropathy and open-angle glaucoma.

PubMed

Rebolleda, Gema; Pérez-Sarriegui, Ane; Díez-Álvarez, Laura; De Juan, Victoria; Muñoz-Negrete, Francisco J

2018-06-01

To compare the optic nerve head morphology among primary open-angle glaucoma, non-arteritic anterior ischemic optic neuropathy eyes, their fellow healthy eyes and control eyes, using spectral-domain optical coherence tomography with enhanced depth imaging. Observational cross-sectional study including 88 eyes of 68 patients. In this study, 23 non-arteritic anterior ischemic optic neuropathy eyes, 17 fellow unaffected eyes, 25 primary open-angle glaucoma eyes, and 23 age-matched control eyes were included. Peripapillary retinal nerve fiber layer thickness and optic disk area were evaluated. Bruch's membrane opening diameter, optic cup depth, anterior lamina cribrosa depth, and prelaminar tissue thickness were assessed. Non-arteritic anterior ischemic optic neuropathy and primary open-angle glaucoma eyes had similar visual field mean deviation and peripapillary retinal nerve fiber layer thickness (P = 0.6 and P = 0.56, respectively). Bruch's membrane opening diameter was significantly larger in primary open-angle glaucoma eyes than in control eyes (P = 0.02). Lamina cribrosa and disk cup were deeper in eyes with primary open-angle glaucoma than both control and non-arteritic anterior ischemic optic neuropathy eyes (P < 0.001). Prelaminar tissue thickness was significantly thinner in primary open-angle glaucoma eyes than in non-arteritic anterior ischemic optic neuropathy eyes (P < 0.001). Lamina cribrosa was shallower in both non-arteritic anterior ischemic optic neuropathy and unaffected fellow eyes compared to healthy eyes (P < 0.001 and P = 0.04, respectively). No differences were found in the optic disk area. A forward lamina cribrosa placement and not a smaller disk could be involved in the pathogenesis of non-arteritic anterior ischemic optic neuropathy. A significantly larger Bruch's membrane opening diameter was found in primary open-angle glaucoma eyes compared with control eyes. This issue has clinical implications because Bruch's membrane opening has been considered a stable reference for disk-related measures.

PROTOSTELLAR OUTFLOWS AND RADIATIVE FEEDBACK FROM MASSIVE STARS. II. FEEDBACK, STAR-FORMATION EFFICIENCY, AND OUTFLOW BROADENING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuiper, Rolf; Turner, Neal J.; Yorke, Harold W., E-mail: rolf.kuiper@uni-tuebingen.de, E-mail: Neal.J.Turner@jpl.nasa.gov, E-mail: Harold.W.Yorke@jpl.nasa.gov

2016-11-20

We perform two-dimensional axially symmetric radiation hydrodynamic simulations to assess the impact of outflows and radiative force feedback from massive protostars by varying when the protostellar outflow starts, and to determine the ratio of ejection to accretion rates and the strength of the wide-angle disk wind component. The star-formation efficiency, i.e., the ratio of final stellar mass to initial core mass, is dominated by radiative forces and the ratio of outflow to accretion rates. Increasing this ratio has three effects. First, the protostar grows slower with a lower luminosity at any given time, lowering radiative feedback. Second, bipolar cavities clearedmore » by the outflow become larger, further diminishing radiative feedback on disk and core scales. Third, the higher momentum outflow sweeps up more material from the collapsing envelope, decreasing the protostar's potential mass reservoir via entrainment. The star-formation efficiency varies with the ratio of ejection to accretion rates from 50% in the case of very weak outflows to as low as 20% for very strong outflows. At latitudes between the low-density bipolar cavity and the high-density accretion disk, wide-angle disk winds remove some of the gas, which otherwise would be part of the accretion flow onto the disk; varying the strength of these wide-angle disk winds, however, alters the final star-formation efficiency by only ±6%. For all cases, the opening angle of the bipolar outflow cavity remains below 20° during early protostellar accretion phases, increasing rapidly up to 65° at the onset of radiation pressure feedback.« less

Genetic correlations between intraocular pressure, blood pressure and primary open-angle glaucoma: a multi-cohort analysis.

PubMed

Aschard, Hugues; Kang, Jae H; Iglesias, Adriana I; Hysi, Pirro; Cooke Bailey, Jessica N; Khawaja, Anthony P; Allingham, R Rand; Ashley-Koch, Allison; Lee, Richard K; Moroi, Sayoko E; Brilliant, Murray H; Wollstein, Gadi; Schuman, Joel S; Fingert, John H; Budenz, Donald L; Realini, Tony; Gaasterland, Terry; Scott, William K; Singh, Kuldev; Sit, Arthur J; Igo, Robert P; Song, Yeunjoo E; Hark, Lisa; Ritch, Robert; Rhee, Douglas J; Gulati, Vikas; Haven, Shane; Vollrath, Douglas; Zack, Donald J; Medeiros, Felipe; Weinreb, Robert N; Cheng, Ching-Yu; Chasman, Daniel I; Christen, William G; Pericak-Vance, Margaret A; Liu, Yutao; Kraft, Peter; Richards, Julia E; Rosner, Bernard A; Hauser, Michael A; Klaver, Caroline C W; vanDuijn, Cornelia M; Haines, Jonathan; Wiggs, Janey L; Pasquale, Louis R

2017-11-01

Primary open-angle glaucoma (POAG) is the most common chronic optic neuropathy worldwide. Epidemiological studies show a robust positive relation between intraocular pressure (IOP) and POAG and modest positive association between IOP and blood pressure (BP), while the relation between BP and POAG is controversial. The International Glaucoma Genetics Consortium (n=27 558), the International Consortium on Blood Pressure (n=69 395), and the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database (n=37 333), represent genome-wide data sets for IOP, BP traits and POAG, respectively. We formed genome-wide significant variant panels for IOP and diastolic BP and found a strong relation with POAG (odds ratio and 95% confidence interval: 1.18 (1.14-1.21), P=1.8 × 10 -27 ) for the former trait but no association for the latter (P=0.93). Next, we used linkage disequilibrium (LD) score regression, to provide genome-wide estimates of correlation between traits without the need for additional phenotyping. We also compared our genome-wide estimate of heritability between IOP and BP to an estimate based solely on direct measures of these traits in the Erasmus Rucphen Family (ERF; n=2519) study using Sequential Oligogenic Linkage Analysis Routines (SOLAR). LD score regression revealed high genetic correlation between IOP and POAG (48.5%, P=2.1 × 10 -5 ); however, genetic correlation between IOP and diastolic BP (P=0.86) and between diastolic BP and POAG (P=0.42) were negligible. Using SOLAR in the ERF study, we confirmed the minimal heritability between IOP and diastolic BP (P=0.63). Overall, IOP shares genetic basis with POAG, whereas BP has limited shared genetic correlation with IOP or POAG.

On the evolution of jet energy and opening angle in strongly coupled plasma

NASA Astrophysics Data System (ADS)

Chesler, Paul M.; Rajagopal, Krishna

2016-05-01

We calculate how the energy and the opening angle of jets in {N} = 4 SYM theory evolve as they propagate through the strongly coupled plasma of that theory. We define the rate of energy loss dE jet /dx and the jet opening angle in a straightforward fashion directly in the gauge theory before calculating both holographically, in the dual gravitational description. In this way, we rederive the previously known result for dE jet /dx without the need to introduce a finite slab of plasma. We obtain a striking relationship between the initial opening angle of the jet, which is to say the opening angle that it would have had if it had found itself in vacuum instead of in plasma, and the thermalization distance of the jet. Via this relationship, we show that {N} = 4 SYM jets with any initial energy that have the same initial opening angle and the same trajectory through the plasma experience the same fractional energy loss. We also provide an expansion that describes how the opening angle of the {N} = 4 SYM jets increases slowly as they lose energy, over the fraction of their lifetime when their fractional energy loss is not yet large. We close by looking ahead toward potential qualitative lessons from our results for QCD jets produced in heavy collisions and propagating through quark-gluon plasma.

On the evolution of jet energy and opening angle in strongly coupled plasma

DOE PAGES

Chesler, Paul M.; Rajagopal, Krishna

2016-05-17

We calculate how the energy and the opening angle of jets in N = 4SYM theory evolve as they propagate through the strongly coupled plasma of that theory. We define the rate of energy loss dE jet/dx and the jet opening angle in a straightforward fashion directly in the gauge theory before calculating both holographically, in the dual gravitational description. In this way, we rederive the previously known result for dE jet/dx without the need to introduce a finite slab of plasma. We obtain a striking relationship between the initial opening angle of the jet, which is to say themore » opening angle that it would have had if it had found itself in vacuum instead of in plasma, and the thermalization distance of the jet. Via this relationship, we show that N = 4SYM jets with any initial energy that have the same initial opening angle and the same trajectory through the plasma experience the same fractional energy loss. We also provide an expansion that describes how the opening angle of the N = 4SYM jets increases slowly as they lose energy, over the fraction of their lifetime when their fractional energy loss is not yet large. In conclusion, we close by looking ahead toward potential qualitative lessons from our results for QCD jets produced in heavy collisions and propagating through quark-gluon plasma.« less

Anterior segment parameters as predictors of intraocular pressure reduction after phacoemulsification in eyes with open-angle glaucoma.

PubMed

Hsia, Yen C; Moghimi, Sasan; Coh, Paul; Chen, Rebecca; Masis, Marisse; Lin, Shan C

2017-07-01

To evaluate intraocular pressure (IOP) change after cataract surgery in eyes with open-angle glaucoma (OAG) and its relationship to angle and anterior segment parameters measured by anterior segment optical coherence tomography (AS-OCT). University of California, San Francisco, California, USA. Prospective case series. Eyes were placed into a narrow-angle group or open-angle group based on gonioscopy grading. Biometric parameters were measured using AS-OCT (Visante) preoperatively, and IOP 4 months after surgery was obtained. The IOP change and its relationship to AS-OCT parameters were evaluated. Eighty-one eyes of 69 patients were enrolled. The mean age of the patients was 76.8 years. The preoperative IOP was 15.02 mm Hg on 1.89 glaucoma medications. The average mean deviation of preoperative visual field was -4.58 dB. The mean IOP reduction was 2.1 mm Hg (12.8%) from a preoperative mean of 15.0 mm Hg. The IOP reduction was significantly greater in eyes with narrow angles than in eyes with open angles (20.4% versus 8.0%) (P = .002). In multivariate analysis, preoperative IOP (β = -0.53, P < .001, R 2  = 0.40), angle-opening distance at 500 mm (β = 5.83, P = .02, R 2  = 0.45), angle-opening distance at 750 mm (β = 5.82, P = .001, R 2  = 0.52), and lens vault (β = -0.002, P = .009, R 2  = 0.47) were associated with IOP reduction postoperatively. In eyes with OAG, IOP reduction after cataract surgery was greater in eyes with narrower angles. Preoperative IOP, angle-opening distance, and lens vault were predictors for IOP reduction. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Biological and aerodynamic problems with the flight of animals

NASA Technical Reports Server (NTRS)

Holst, E. V.; Kuchemann, D.

1980-01-01

Biological and aerodynamic considerations related to birds and insects are discussed. A wide field is open for comparative biological, physiological, and aerodynamic investigations. Considerable mathematics related to the flight of animals is presented, including 20 equations. The 15 figures included depict the design of bird and insect wings, diagrams of propulsion efficiency, thrust, lift, and angles of attack and photographs of flapping wing free flying wing only models which were built and flown.

Thermally Tunable Hydrogels Displaying Angle-Independent Structural Colors.

PubMed

Ohtsuka, Yumiko; Seki, Takahiro; Takeoka, Yukikazu

2015-12-14

We report the preparation of thermally tunable hydrogels displaying angle-independent structural colors. The porous structures were formed with short-range order using colloidal amorphous array templates and a small amount of carbon black (CB). The resultant porous hydrogels prepared using colloidal amorphous arrays without CB appeared white, whereas the hydrogels with CB revealed bright structural colors. The brightly colored hydrogels rapidly changed hues in a reversible manner, and the hues varied widely depending on the water temperature. Moreover, the structural colors were angle-independent under diffusive lighting because of the isotropic nanostructure generated from the colloidal amorphous arrays. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

A Generalized Maxwell Model for Creep Behavior of Artery Opening Angle

PubMed Central

Zhang, W.; Guo, X.; Kassab, G. S.

2009-01-01

An artery ring springs open into a sector after a radial cut. The opening angle characterizes the residual strain in the unloaded state, which is fundamental to understanding stress and strain in the vessel wall. A recent study revealed that the opening angle decreases with time if the artery is cut from the loaded state, while it increases if the cut is made from the no-load state due to viscoelasticity. In both cases, the opening angle approaches the same value in 3 hours. This implies that the characteristic relaxation time is about 10,000 sec. Here, the creep function of a generalized Maxwell model (a spring in series with six Voigt bodies) is used to predict the temporal change of opening angle in multiple time scales. It is demonstrated that the theoretical model captures the salient features of the experimental results. The proposed creep function may be extended to study the viscoelastic response of blood vessels under various loading conditions. PMID:19045526

Mechanical oscillatory behavior of a C60 fullerene tunneling through open carbon nanocones

NASA Astrophysics Data System (ADS)

Sadeghi, F.; Ansari, R.

2017-07-01

This paper deals with the mechanical oscillatory behavior of a C60 fullerene inside open carbon nanocones (CNCs). The fullerene molecule is assumed to enter the nanocone through its small end or wide end. Following our previously published study, semi-analytical expressions for the evaluation of vdW interactions are presented which facilitate obtaining a formula for oscillation frequency. The equation of motion is numerically solved to attain the time histories of separation distance and velocity of the fullerene molecule. Based on the conservation of the mechanical energy law, a new semi-analytical formula is also derived to accurately evaluate the oscillation frequency of the system. With respect to the present formulation, a detailed parametric study is conducted to gain an insight into the effects of both geometrical parameters (small-end radius, wide-end radius and vertex angle of nanocone) and initial conditions (initial separation distance and initial velocity) on the oscillatory behavior of C60 fullerene-open CNC oscillators. For given geometrical parameters and initial conditions, it is shown that higher oscillation frequencies can be achieved when the fullerene molecule enters the open nanocone through its small end.

The distinction between juvenile and adult-onset primary open-angle glaucoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiggs, J.L.; Haines, J.L.; Damji, K.F.

1996-01-01

Because of the significant differences between the juvenile and adult forms of open-angle glaucoma, especially with regard to inheritance, prevalence, severity, and age of onset, we read with interest the recent publication by Morissette et al., describing a pedigree with a phenotype that overlaps the distinctive features of juvenile-onset open-angle glaucoma (JOAG) and adult-onset primary open-angle glaucoma (usually abbreviated as POAG or COAG). These authors conclude that a gene mapped to human chromosome 1q21-q31 (GLC1A) can be responsible for both juvenile and adult forms of open-angle glaucoma. The implications of such a result could be extremely important, in light ofmore » the high prevalence of the adult form of the disease. However, while the data presented in this report suggest that variable expressivity of the GLC1A gene may lead to a broader range of onset for this form of juvenile glaucoma, these data do not identify the GLC1A gene as an important cause of POAG. To prevent misleading interpretations of this and similar studies, we wish to clarify the distinction between the juvenile and adult forms of open-angle glaucoma. 8 refs.« less

Factors associated with postoperative C5 palsy after expansive open-door laminoplasty: retrospective cohort study using multivariable analysis.

PubMed

Tsuji, Takashi; Matsumoto, Morio; Nakamura, Masaya; Ishii, Ken; Fujita, Nobuyuki; Chiba, Kazuhiro; Watanabe, Kota

2017-09-01

The aim of the present study was to investigate the factors associated with C5 palsy by focusing on radiological parameters using multivariable analysis. The authors retrospectively assessed 190 patients with cervical spondylotic myelopathy treated by open-door laminoplasty. Four radiographic parameters-the number of expanded lamina, C3-C7 angle, lamina open angle and space anterior to the spinal cord-were evaluated to clarify the factors associated with C5 palsy. Of the 190 patients, 11 developed C5 palsy, giving an overall incidence of 5.8%. Although the number of expanded lamina, lamina open angle and space anterior to the spinal cord were significantly larger in C5 palsy group than those in non-palsy group, a multiple logistic regression analysis revealed that only the space anterior to the spinal cord (odds ratio 2.60) was a significant independent factor associated with C5 palsy. A multiple linear regression analysis indicated that the lamina open angle was associated with the space anterior to the spinal cord and the analysis identified the following equation: space anterior to the spinal cord (mm) = 1.54 + 0.09 × lamina open angle (degree). A cut-off value of 53.5° for the lamina open angle predicted the development of C5 palsy with a sensitivity of 72.7% and a specificity of 83.2%. The larger postoperative space anterior to the spinal cord, which was associated with the lamina open angle, was positively correlated with the higher incidence of C5 palsy.

Changes in Anterior Segment Morphology and Predictors of Angle Widening after Laser Iridotomy in South Indian Eyes.

PubMed

Zebardast, Nazlee; Kavitha, Srinivasan; Krishnamurthy, Palaniswamy; Friedman, David S; Nongpiur, Monisha E; Aung, Tin; Quigley, Harry A; Ramulu, Pradeep Y; Venkatesh, Rengaraj

2016-12-01

To compare anterior segment optical coherence tomography (ASOCT) angle morphology before and after laser peripheral iridotomy (LPI) in a cohort of South Indian subjects with primary angle-closure suspect (PACS) or primary angle-closure/primary angle-closure glaucoma (PAC/PACG) and to examine baseline parameters associated with angle widening. Prospective observational study. A total of 244 subjects aged ≥30 years with PACS or PAC/PACG in at least 1 eye. The ASOCT images and angle gonioscopic grades were analyzed for all subjects at baseline and 2 weeks after LPI. Multivariable linear and logistic regression models were used to determine predictors of angle widening (change in mean angle opening distance [AOD750]) and angle opening (all 4 quadrants with trabecular meshwork [TM] visible on gonioscopy after LPI). Change in ASOCT parameters with LPI and baseline predictors of angle widening. Laser peripheral iridotomy resulted in angle widening on ASOCT with significant increases in AOD750, angle recess area, and trabecular iris surface area (P < 0.05 for all). Gonioscopically, 44.7% of all subjects had open angles in all 4 quadrants after LPI, with a greater percentage of angles open in the PACS group compared with the PAC/PACG group (52.4% vs. 36.4%; P = 0.01). In multivariable regression analyses, greater postoperative angle widening as defined by change in AOD750 was associated with shorter baseline AOD750 and axial length, and greater baseline anterior chamber depth, iris curvature, and lens vault (P ≤ 0.002 for all). Gonioscopic angle opening after LPI was more common with wider baseline angle width (modified Shaffer grade) and lower cup-to-disc ratio (P < 0.001 for both). In a South Indian population with PACS or PAC/PACG, LPI results in significant anterior chamber angle widening seen on both ASOCT and gonioscopy, although some degree of persistent iridotrabecular contact was present in approximately half of PACS eyes and approximately two thirds of PAC/PACG eyes on gonioscopy. The greatest widening by ASOCT was observed in eyes with features most consistent with greater baseline pupillary block. Copyright © 2016 American Academy of Ophthalmology. All rights reserved.

Supersonic axial-force characteristics of a rectangular-box cavity with various length-to-depth ratios in a flat plate

NASA Technical Reports Server (NTRS)

Blair, A. B., Jr.; Stallings, R. L., Jr.

1986-01-01

A wind-tunnel investigation has been conducted at Mach numbers of 1.50, 2.16, and 2.86 to obtain axial-force data on a metric rectangular-box cavity with various length-to-depth ratios. The model was tested at angles of attack from -4 deg to -2 deg. The results are summarized to show variations in cavity axial-force coefficient for deep- and shallow-cavity configurations with detached and attached cavity flow fields, respectively. The results of the investigation indicate that for a wide range of cavity lengths and depths, good correlations of the cavity axial-force coefficients (based on cavity rear-face area) are obtained when these coefficients are plotted as a function of cavity length-to-depth ratio. Abrupt increases in the cavity axial-force coefficients at an angle of attack of 0 deg. reflect the transition from an open (detached) cavity flow field to a closed (attached) cavity flow field. Cavity length-to-depth ratio is the dominant factor affecting the switching of the cavity flow field from one type to the other. The type of cavity flow field (open or closed) is not dependent on the test angles of attack except near the critical value of length-to-depth ratio.

The Physics of Imaging with Remote Sensors : Photon State Space & Radiative Transfer

NASA Technical Reports Server (NTRS)

Davis, Anthony B.

2012-01-01

Standard (mono-pixel/steady-source) retrieval methodology is reaching its fundamental limit with access to multi-angle/multi-spectral photo- polarimetry. Next... Two emerging new classes of retrieval algorithm worth nurturing: multi-pixel time-domain Wave-radiometry transition regimes, and more... Cross-fertilization with bio-medical imaging. Physics-based remote sensing: - What is "photon state space?" - What is "radiative transfer?" - Is "the end" in sight? Two wide-open frontiers! center dot Examples (with variations.

Experimental measurements of heat transfer coefficient in a partially/fully opened tilted cavity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakroun, W.; Elsayed, M.M.; Al-Fahed, S.F.

1997-11-01

An experimental investigation was carried out to determine the heat transfer coefficient from a rectangular tilted cavity to the ambient due to the buoyancy driven flow in the cavity. The cavity is partially or fully open from one side. All the walls of the cavity are adiabatic except the wall facing the cavity opening which is heated at a constant heat flux. Air was used as the cavity fluid and the experiments were carried out at a flux Grashof number of 5.5 {times} 10{sup 8}. The tilt angle of the cavity, measured from the vertical direction, was changed between {minus}90more » deg to +90 deg in 15 deg increments. Also, geometries of aspect ratio (height-to-width of cavity) of 1.0, 0.5, and 0.25 and of opening ratio (opening height to cavity height) of 1.0, 0.5, and 0.25 were considered in the study. The results are presented in terms of the average Nusselt number for different values of the above experimental parameters. Conclusions are derived for the effect of changing the tilt angle, the aspect ratio, or the opening ratio of the cavity on the average heat transfer coefficient between the cavity and the ambient air. Buoyancy-driven flow in rectangular cavities has been widely investigated by many researchers. This geometry is of special interest in many solar applications such as in solar passive heating, solar concentrators, and solar central receivers. The importance of the geometry extends to other engineering applications such as electronic equipment, fire research, and energy conservation in buildings.« less

Wide-angle seismic data from the East Sicily margin: Imaging the deep structure of a Tethyan transform margin and the modern Calabria subduction lateral slab tear.

NASA Astrophysics Data System (ADS)

Dellong, D.; Klingelhoefer, F.; Kopp, H.; Gutscher, M. A.

2016-12-01

It is generally accepted that a STEP fault (Subduction Tear Edge Propagator) has accommodated the roll back of the Ionian Slab along the eastern Sicily Margin since 6 to 7 Ma. However the location of this lithospheric scale tear fault, and its surface expression is controversial. Constrain by numerous bathymetric imaging and shallow sub-surface multi-channels seismic (MCS) studies, variety of fault geometry was proposed. Moreover the role of the Malta Escarpment in this geodynamic system also remain the object of debates. It may be linked to the opening of the Ionian basin during a phase of strike-slip rifting since more than 180 Ma. Here we present the results of modelling of two wide-angle seismic profiles from the DIONYSUS survey (R/V Meteor, Oct. 2014). The first profile (DY-P3) was recorded by 25 Ocean- Bottom-Seismometers (OBS) and 3 land stations, and the second profile (DY-P1) by 52 OBS. Forward modelling of both profiles reveals a zone of abrupt crustal thinning from about 30 km below the Hyblean plateau and East-Sicily continental domain, to values of 8-15 km over a short lateral distance of 20-30 km. In the northern profile (DY-P3) the crust east of this abrupt thinning is of transitional thickness (15 km) and characterized by seismic velocities and velocity gradients similar to thinned continental crust. In the southern profile (DY-P1) this crust is 6-8 km thick, and the velocity gradients are close to those of oceanic crust. On this profile about 50-60 km eastward from the base of the Malta Escarpment, a lateral change of crustal velocities was modelled. Here a recent shallow transtensional deformation has been observed in MCS data at the position of this structure and linked to an elongated basin visible in the bathymetry and was linked to the STEP fault location. The results of the wide-angle seismic modelling suggest an ancient origin for the Malta Escarpment, formed as a transform margin during opening of the Ionian Basin about 180 Ma ago. The geometry of the modern day STEP fault is largely obscured in the northern profile because of the superposition of the structures with the ancient Tethyan transform Margin. In the southern wide-angle seismic profile these two structures are distinct and this allow us to conclude that the Malta Escarpment offshore SE Sicily has not been re-activated by the recent STEP-fault activity.

Undetected angle closure in patients with a diagnosis of open-angle glaucoma.

PubMed

Varma, Devesh K; Simpson, Sarah M; Rai, Amandeep S; Ahmed, Iqbal Ike K

2017-08-01

The aim of this study was to identify the proportion of patients referred to a tertiary glaucoma centre with a diagnosis of open-angle glaucoma (OAG) who were found to have angle closure glaucoma. Retrospective chart review. Consecutive new patients referred for glaucoma management to a tertiary centre between July 2010 and December 2011 were reviewed. Patients whose referrals for glaucoma assessment specified angle status as "open" were included. The data collected included glaucoma specialist's angle assessment, diagnosis, and glaucoma severity. The status of those with 180 degrees or more Shaffer angle grading of 0 was classified as "closed." From 1234 glaucoma referrals, 179 cases were specified to have a diagnosis of OAG or when angles were known to be open. Of these, 16 (8.9%) were found on examination by the glaucoma specialist to have angle closure. Pseudoexfoliation was present in 4 of 16 patients (25%) in the missed angle-closure glaucoma (ACG) group and 22 of 108 patients (13.5%) in the remaining OAG group. There was no difference found in demographic or ocular biometric parameters between those with confirmed OAG versus those with missed ACG. Almost 1 in 11 patients referred by ophthalmologists to a tertiary glaucoma centre with a diagnosis of OAG were in fact found to have angle closure. Given the different treatment approaches for ACG versus OAG, this study suggests a need to strengthen angle evaluations. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Monte Carlo-based assessment of the trade-off between spatial resolution, field-of-view and scattered radiation in the variable resolution X-ray CT scanner.

PubMed

Arabi, Hossein; Kamali Asl, Ali Reza; Ay, Mohammad Reza; Zaidi, Habib

2015-07-01

The purpose of this work is to evaluate the impact of optimization of magnification on performance parameters of the variable resolution X-ray (VRX) CT scanner. A realistic model based on an actual VRX CT scanner was implemented in the GATE Monte Carlo simulation platform. To evaluate the influence of system magnification, spatial resolution, field-of-view (FOV) and scatter-to-primary ratio of the scanner were estimated for both fixed and optimum object magnification at each detector rotation angle. Comparison and inference between these performance parameters were performed angle by angle to determine appropriate object position at each opening half angle. Optimization of magnification resulted in a trade-off between spatial resolution and FOV of the scanner at opening half angles of 90°-12°, where the spatial resolution increased up to 50% and the scatter-to-primary ratio decreased from 4.8% to 3.8% at a detector angle of about 90° for the same FOV and X-ray energy spectrum. The disadvantage of magnification optimization at these angles is the significant reduction of the FOV (up to 50%). Moreover, magnification optimization was definitely beneficial for opening half angles below 12° improving the spatial resolution from 7.5 cy/mm to 20 cy/mm. Meanwhile, the FOV increased by more than 50% at these angles. It can be concluded that optimization of magnification is essential for opening half angles below 12°. For opening half angles between 90° and 12°, the VRX CT scanner magnification should be set according to the desired spatial resolution and FOV. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Lack of Association of Mutations in Optineurin With Disease in Patients With Adult-onset Primary Open-angle Glaucoma

PubMed Central

Wiggs, Janey L.; Auguste, Josette; Allingham, R. Rand; Flor, Jason D.; Pericak-Vance, Margaret A.; Rogers, Kathryn; LaRocque, Karen R.; Graham, Felicia L.; Broomer, Bob; Del Bono, Elizabeth; Haines, Jonathan L.; Hauser, Michael

2005-01-01

Objective: To determine whether mutations in the optineurin gene contribute to susceptibility to adult-onset primary open-angle glaucoma. Methods: The optineurin gene was screened in 86 probands with adult-onset primary open-angle glaucoma and in 80 age-matched control subjects. Exons 4 and 5, containing the recurrent mutations identified in patients with normal-tension glaucoma, were sequenced in all individuals studied, while the remaining exons were screened for DNA sequence variants with denaturing high-performance liquid chromatography. Results: The recurrent mutation, Met98Lys, previously found to be associated with an increased risk of disease was found in 8 (9%) of 86 probands. We also found the Met98Lys mutation in 10% of individuals from a control population of similar age, sex, and ethnicity. Consistent segregation of the mutation with the disease was not demonstrated in any of the 8 families. No other DNA changes altering the amino acid structure of the protein were found. Conclusion: The mutations in the optineurin gene associated with normal-tension glaucoma are not associated with adult-onset primary open-angle glaucoma in this patient population. Clinical Relevance: Genetic abnormalities that render the optic nerve susceptible to degeneration are excellent candidates for genetic factors that could contribute to adult-onset primary open-angle glaucoma. Mutations in optineurin have been associated with normal-tension glaucoma, but are not associated with disease in patients with adult-onset primary open-angle glaucoma. This result may indicate that normal-tension glaucoma is not necessarily part of the phenotypic spectrum of adult open-angle glaucoma. PMID:12912697

Common variants near ABCA1, AFAP1 and GMDS confer risk of primary open-angle glaucoma

PubMed Central

Fogarty, Rhys; Sharma, Shiwani; Hewitt, Alex W.; Martin, Sarah; Law, Matthew H.; Cremin, Katie; Bailey, Jessica N. Cooke; Loomis, Stephanie J.; Pasquale, Louis R.; Haines, Jonathan L.; Hauser, Michael A.; Viswanathan, Ananth C.; McGuffin, Peter; Topouzis, Fotis; Foster, Paul J.; Graham, Stuart L; Casson, Robert J; Chehade, Mark; White, Andrew J; Zhou, Tiger; Souzeau, Emmanuelle; Landers, John; Fitzgerald, Jude T; Klebe, Sonja; Ruddle, Jonathan B; Goldberg, Ivan; Healey, Paul R; Mills, Richard A.; Wang, Jie Jin; Montgomery, Grant W.; Martin, Nicholas G.; Radford-Smith, Graham; Whiteman, David C.; Brown, Matthew A.; Wiggs, Janey L.; Mackey, David A; Mitchell, Paul; MacGregor, Stuart; Craig, Jamie E.

2014-01-01

Primary open-angle glaucoma (POAG) is a major cause of irreversible blindness worldwide. We performed a genome-wide association study in an Australian discovery cohort comprising 1,155 advanced POAG cases and 1,992 controls. Association of the top SNPs from the discovery stage was investigated in two Australian replication cohorts (total 932 cases, 6,862 controls) and two US replication cohorts (total 2,616 cases, 2,634 controls). Meta-analysis of all cohorts revealed three novel loci associated with development of POAG. These loci are located upstream of ABCA1 (rs2472493 [G] OR=1.31, P= 2.1 × 10−19), within AFAP1 (rs4619890 [G] OR=1.20, P= 7.0 × 10−10) and within GMDS (rs11969985 [G] OR=1.31, and P= 7.7 × 10−10). Using RT-PCR and immunolabelling, we also showed that these genes are expressed within human retina, optic nerve and trabecular meshwork and that ABCA1 and AFAP1 are also expressed in retinal ganglion cells. PMID:25173105

Anterior Segment Imaging Predicts Incident Gonioscopic Angle Closure.

PubMed

Baskaran, Mani; Iyer, Jayant V; Narayanaswamy, Arun K; He, Yingke; Sakata, Lisandro M; Wu, Renyi; Liu, Dianna; Nongpiur, Monisha E; Friedman, David S; Aung, Tin

2015-12-01

To investigate the incidence of gonioscopic angle closure after 4 years in subjects with gonioscopically open angles but varying degrees of angle closure detected on anterior segment optical coherence tomography (AS OCT; Visante; Carl Zeiss Meditec, Dublin, CA) at baseline. Prospective, observational study. Three hundred forty-two subjects, mostly Chinese, 50 years of age or older, were recruited, of whom 65 were controls with open angles on gonioscopy and AS OCT at baseline, and 277 were cases with baseline open angles on gonioscopy but closed angles (1-4 quadrants) on AS OCT scans. All subjects underwent gonioscopy and AS OCT at baseline (horizontal and vertical single scans) and after 4 years. The examiner performing gonioscopy was masked to the baseline and AS OCT data. Angle closure in a quadrant was defined as nonvisibility of the posterior trabecular meshwork by gonioscopy and visible iridotrabecular contact beyond the scleral spur in AS OCT scans. Gonioscopic angle closure in 2 or 3 quadrants after 4 years. There were no statistically significant differences in age, ethnicity, or gender between cases and controls. None of the control subjects demonstrated gonioscopic angle closure after 4 years. Forty-eight of the 277 subjects (17.3%; 95% confidence interval [CI], 12.8-23; P < 0.0001) with at least 1 quadrant of angle closure on AS OCT at baseline demonstrated gonioscopic angle closure in 2 or more quadrants, whereas 28 subjects (10.1%; 95% CI, 6.7-14.6; P < 0.004) demonstrated gonioscopic angle closure in 3 or more quadrants after 4 years. Individuals with more quadrants of angle closure on baseline AS OCT scans had a greater likelihood of gonioscopic angle closure developing after 4 years (P < 0.0001, chi-square test for trend for both definitions of angle closure). Anterior segment OCT imaging at baseline predicts incident gonioscopic angle closure after 4 years among subjects who have gonioscopically open angles and iridotrabecular contact on AS OCT at baseline. Copyright © 2015 American Academy of Ophthalmology. All rights reserved.

Open arthrolysis for elbow stiffness increases carrying angle but has no impact on functional recovery.

PubMed

Fan, Dapeng; Wang, Wei; Hildebrand, Kevin A; Fan, Cun-Yi

2016-09-09

With the exception of normal anatomic changes in the medial collateral ligament and radial head, other factors related to carrying angle changes have not been systematically studied. We reviewed patients who underwent open arthrolysis of the elbow, and evaluated if open arthrolysis could change carrying angle. We then identified factors associated with carrying angle changes. Fifty patients with a minimum of 24 months of follow-up after open arthrolysis were evaluated retrospectively. Preoperative and postoperative carrying angles were compared. The carrying angles of 36 elbows in 36 patients were unchanged after surgery (Group A), while the carrying angles of 14 elbows in 14 patients increased postoperatively (Group B). In Group A, mean postoperative extension and flexion were 7° (range 0-24°) and 125° (range 10-135°) respectively, while mean postoperative pronation and supination were 60° (range 50-80°) and 65° (range 30-85°), respectively. In Group B, mean postoperative extension and flexion were 25° (range 0-40°) and 128° (range 60-138°), while mean postoperative pronation and supination were 65° (range 45-85°) and 60° (range 45-75°), respectively. No significant difference in range of motion and Mayo Elbow Performance Score was observed between the two groups. During open arthrolysis, humeral trochlea debridement and techniques for improving forearm rotation could increase carrying angle. However, this had no impact on elbow functional recovery.

Obstructive sleep apnoea syndrome in patients with primary open-angle glaucoma.

PubMed

Balbay, Ege G; Balbay, Oner; Annakkaya, Ali N; Suner, Kezban O; Yuksel, Harun; Tunç, Murat; Arbak, Peri

2014-10-01

To investigate the prevalence of obstructive sleep apnoea syndrome in patients with primary open-angle glaucoma. Case series. School of Medicine, Düzce University, Turkey. Twenty-one consecutive primary open-angle glaucoma patients (12 females and 9 males) who attended the out-patient clinic of the Department of Ophthalmology between July 2007 and February 2008 were included in this study. All patients underwent polysomnographic examination. The prevalence of obstructive sleep apnoea syndrome was 33.3% in patients with primary open-angle glaucoma; the severity of the condition was mild in 14.3% and moderate in 19.0% of the subjects. The age (P=0.047) and neck circumference (P=0.024) in patients with obstructive sleep apnoea syndrome were significantly greater than those without the syndrome. Triceps skinfold thickness in glaucomatous obstructive sleep apnoea syndrome patients reached near significance versus those without the syndrome (P=0.078). Snoring was observed in all glaucoma cases with obstructive sleep apnoea syndrome. The intra-ocular pressure of patients with primary open-angle glaucoma with obstructive sleep apnoea syndrome was significantly lower than those without obstructive sleep apnoea syndrome (P=0.006 and P=0.035 for the right and left eyes, respectively). There was no significant difference in the cup/disc ratio and visual acuity, except visual field defect, between primary open-angle glaucoma patients with and without obstructive sleep apnoea syndrome. Although it does not provide evidence for a cause-effect relationship, high prevalence of obstructive sleep apnoea syndrome in patients with primary open-angle glaucoma in this study suggests the need to explore the long-term results of coincidence, relationship, and cross-interaction of these two common disorders.

Tank-Binding Kinase 1 (TBK1) Gene and Open-Angle Glaucomas (An American Ophthalmological Society Thesis)

PubMed Central

Fingert, John H.; Robin, Alan L.; Scheetz, Todd E.; Kwon, Young H.; Liebmann, Jeffrey M.; Ritch, Robert; Alward, Wallace L.M.

2016-01-01

Purpose To investigate the role of TANK-binding kinase 1 (TBK1) gene copy-number variations (ie, gene duplications and triplications) in the pathophysiology of various open-angle glaucomas. Methods In previous studies, we discovered that copy-number variations in the TBK1 gene are associated with normal-tension glaucoma. Here, we investigated the prevalence of copy-number variations in cohorts of patients with other open-angle glaucomas—juvenile-onset open-angle glaucoma (n=30), pigmentary glaucoma (n=209), exfoliation glaucoma (n=225), and steroid-induced glaucoma (n=79)—using a quantitative polymerase chain reaction assay. Results No TBK1 gene copy-number variations were detected in patients with juvenile-onset open-angle glaucoma, pigmentary glaucoma, or steroid-induced glaucoma. A TBK1 gene duplication was detected in one (0.44%) of the 225 exfoliation glaucoma patients. Conclusions TBK1 gene copy-number variations (gene duplications and triplications) have been previously associated with normal-tension glaucoma. An exploration of other open-angle glaucomas detected a TBK1 copy-number variation in a patient with exfoliation glaucoma, which is the first example of a TBK1 mutation in a glaucoma patient with a diagnosis other than normal-tension glaucoma. A broader phenotypic range may be associated with TBK1 copy-number variations, although mutations in this gene are most often detected in patients with normal-tension glaucoma. PMID:27881886

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chesler, Paul M.; Rajagopal, Krishna

We calculate how the energy and the opening angle of jets in N = 4SYM theory evolve as they propagate through the strongly coupled plasma of that theory. We define the rate of energy loss dE jet/dx and the jet opening angle in a straightforward fashion directly in the gauge theory before calculating both holographically, in the dual gravitational description. In this way, we rederive the previously known result for dE jet/dx without the need to introduce a finite slab of plasma. We obtain a striking relationship between the initial opening angle of the jet, which is to say themore » opening angle that it would have had if it had found itself in vacuum instead of in plasma, and the thermalization distance of the jet. Via this relationship, we show that N = 4SYM jets with any initial energy that have the same initial opening angle and the same trajectory through the plasma experience the same fractional energy loss. We also provide an expansion that describes how the opening angle of the N = 4SYM jets increases slowly as they lose energy, over the fraction of their lifetime when their fractional energy loss is not yet large. In conclusion, we close by looking ahead toward potential qualitative lessons from our results for QCD jets produced in heavy collisions and propagating through quark-gluon plasma.« less

Tank-Binding Kinase 1 (TBK1) Gene and Open-Angle Glaucomas (An American Ophthalmological Society Thesis).

PubMed

Fingert, John H; Robin, Alan L; Scheetz, Todd E; Kwon, Young H; Liebmann, Jeffrey M; Ritch, Robert; Alward, Wallace L M

2016-08-01

To investigate the role of TANK-binding kinase 1 ( TBK1 ) gene copy-number variations (ie, gene duplications and triplications) in the pathophysiology of various open-angle glaucomas. In previous studies, we discovered that copy-number variations in the TBK1 gene are associated with normal-tension glaucoma. Here, we investigated the prevalence of copy-number variations in cohorts of patients with other open-angle glaucomas-juvenile-onset open-angle glaucoma (n=30), pigmentary glaucoma (n=209), exfoliation glaucoma (n=225), and steroid-induced glaucoma (n=79)-using a quantitative polymerase chain reaction assay. No TBK1 gene copy-number variations were detected in patients with juvenile-onset open-angle glaucoma, pigmentary glaucoma, or steroid-induced glaucoma. A TBK1 gene duplication was detected in one (0.44%) of the 225 exfoliation glaucoma patients. TBK1 gene copy-number variations (gene duplications and triplications) have been previously associated with normal-tension glaucoma. An exploration of other open-angle glaucomas detected a TBK1 copy-number variation in a patient with exfoliation glaucoma, which is the first example of a TBK1 mutation in a glaucoma patient with a diagnosis other than normal-tension glaucoma. A broader phenotypic range may be associated with TBK1 copy-number variations, although mutations in this gene are most often detected in patients with normal-tension glaucoma.

EC95-43057-8

NASA Image and Video Library

1995-03-24

Outlined with gold stripes are the hinged nose strakes, modifications made to NASA's F-18 HARV (High Alpha Research Vehicle) at the Dryden Flight Research Center, Edwards, California. Actuated Nose Strakes for Enhanced Rolling (ANSER) were installed to fly the third and final phase in the HARV flight test project. Normally folded flush, the units -- four feet long and six inches wide -- can be opened independently to interact with the nose vortices to produce large side forces for control. Early wind tunnel tests indicated that the strakes would be as effective in yaw control at high angles of attack as rudders are at lower angles. Testing involved evaluation of the strakes by themselves as well as combined with the aircraft's Thrust Vectoring System. The strakes were designed by NASA's Langley Research Center, then installed and flight tested at Dryden.

Internal reflection sensors with high angular resolution

NASA Astrophysics Data System (ADS)

Shavirin, I.; Strelkov, O.; Vetskous, A.; Norton-Wayne, L.; Harwood, R.

1996-07-01

We discuss the use of total internal reflection for the production of sensors with high angular resolution. These sensors are intended for measurement of the angle between a sensor's axis and the direction to a source of radiation or reflecting object. Sensors of this type are used in controlling the position of machine parts in robotics and industry, orienting space vehicles and astronomic devices in relation to the Sun, and as autocollimators for checking angles of deviation. This kind of sensor was used in the Apollo space vehicle some 20 years ago. Using photodetectors with linear and area CCD arrays has opened up new application possibilities for appropriately designed sensors. A generalized methodology is presented applicable to a wide range of tasks. Some modifications that can improve the performance of the basic design are described.

Auditory processing deficits in individuals with primary open-angle glaucoma.

PubMed

Rance, Gary; O'Hare, Fleur; O'Leary, Stephen; Starr, Arnold; Ly, Anna; Cheng, Belinda; Tomlin, Dani; Graydon, Kelley; Chisari, Donella; Trounce, Ian; Crowston, Jonathan

2012-01-01

The high energy demand of the auditory and visual pathways render these sensory systems prone to diseases that impair mitochondrial function. Primary open-angle glaucoma, a neurodegenerative disease of the optic nerve, has recently been associated with a spectrum of mitochondrial abnormalities. This study sought to investigate auditory processing in individuals with open-angle glaucoma. DESIGN/STUDY SAMPLE: Twenty-seven subjects with open-angle glaucoma underwent electrophysiologic (auditory brainstem response), auditory temporal processing (amplitude modulation detection), and speech perception (monosyllabic words in quiet and background noise) assessment in each ear. A cohort of age, gender and hearing level matched control subjects was also tested. While the majority of glaucoma subjects in this study demonstrated normal auditory function, there were a significant number (6/27 subjects, 22%) who showed abnormal auditory brainstem responses and impaired auditory perception in one or both ears. The finding that a significant proportion of subjects with open-angle glaucoma presented with auditory dysfunction provides evidence of systemic neuronal susceptibility. Affected individuals may suffer significant communication difficulties in everyday listening situations.

Genome-wide analysis of central corneal thickness in primary open-angle glaucoma cases in the NEIGHBOR and GLAUGEN consortia.

PubMed

Ulmer, Megan; Li, Jun; Yaspan, Brian L; Ozel, Ayse Bilge; Richards, Julia E; Moroi, Sayoko E; Hawthorne, Felicia; Budenz, Donald L; Friedman, David S; Gaasterland, Douglas; Haines, Jonathan; Kang, Jae H; Lee, Richard; Lichter, Paul; Liu, Yutao; Pasquale, Louis R; Pericak-Vance, Margaret; Realini, Anthony; Schuman, Joel S; Singh, Kuldev; Vollrath, Douglas; Weinreb, Robert; Wollstein, Gadi; Zack, Donald J; Zhang, Kang; Young, Terri; Allingham, R Rand; Wiggs, Janey L; Ashley-Koch, Allison; Hauser, Michael A

2012-07-03

To investigate the effects of central corneal thickness (CCT)-associated variants on primary open-angle glaucoma (POAG) risk using single nucleotide polymorphisms (SNP) data from the Glaucoma Genes and Environment (GLAUGEN) and National Eye Institute (NEI) Glaucoma Human Genetics Collaboration (NEIGHBOR) consortia. A replication analysis of previously reported CCT SNPs was performed in a CCT dataset (n = 1117) and these SNPs were then tested for association with POAG using a larger POAG dataset (n = 6470). Then a CCT genome-wide association study (GWAS) was performed. Top SNPs from this analysis were selected and tested for association with POAG. cDNA libraries from fetal and adult brain and ocular tissue samples were generated and used for candidate gene expression analysis. Association with one of 20 previously published CCT SNPs was replicated: rs12447690, near the ZNF469 gene (P = 0.001; β = -5.08 μm/allele). None of these SNPs were significantly associated with POAG. In the CCT GWAS, no SNPs reached genome-wide significance. After testing 50 candidate SNPs for association with POAG, one SNP was identified, rs7481514 within the neurotrimin (NTM) gene, that was significantly associated with POAG in a low-tension subset (P = 0.00099; Odds Ratio [OR] = 1.28). Additionally, SNPs in the CNTNAP4 gene showed suggestive association with POAG (top SNP = rs1428758; P = 0.018; OR = 0.84). NTM and CNTNAP4 were shown to be expressed in ocular tissues. The results suggest previously reported CCT loci are not significantly associated with POAG susceptibility. By performing a quantitative analysis of CCT and a subsequent analysis of POAG, SNPs in two cell adhesion molecules, NTM and CNTNAP4, were identified and may increase POAG susceptibility in a subset of cases.

Partially-overlapped viewing zone based integral imaging system with super wide viewing angle.

PubMed

Xiong, Zhao-Long; Wang, Qiong-Hua; Li, Shu-Li; Deng, Huan; Ji, Chao-Chao

2014-09-22

In this paper, we analyze the relationship between viewer and viewing zones of integral imaging (II) system and present a partially-overlapped viewing zone (POVZ) based integral imaging system with a super wide viewing angle. In the proposed system, the viewing angle can be wider than the viewing angle of the conventional tracking based II system. In addition, the POVZ can eliminate the flipping and time delay of the 3D scene as well. The proposed II system has a super wide viewing angle of 120° without flipping effect about twice as wide as the conventional one.

Automatic helmet-wearing detection for law enforcement using CCTV cameras

NASA Astrophysics Data System (ADS)

Wonghabut, P.; Kumphong, J.; Satiennam, T.; Ung-arunyawee, R.; Leelapatra, W.

2018-04-01

The objective of this research is to develop an application for enforcing helmet wearing using CCTV cameras. The developed application aims to help law enforcement by police, and eventually resulting in changing risk behaviours and consequently reducing the number of accidents and its severity. Conceptually, the application software implemented using C++ language and OpenCV library uses two different angle of view CCTV cameras. Video frames recorded by the wide-angle CCTV camera are used to detect motorcyclists. If any motorcyclist without helmet is found, then the zoomed (narrow-angle) CCTV is activated to capture image of the violating motorcyclist and the motorcycle license plate in real time. Captured images are managed by database implemented using MySQL for ticket issuing. The results show that the developed program is able to detect 81% of motorcyclists on various motorcycle types during daytime and night-time. The validation results reveal that the program achieves 74% accuracy in detecting the motorcyclist without helmet.

46 CFR 172.065 - Damage stability.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of sinkage, heel, and trim, must be below the lower edge of an opening through which progressive... sliding watertight door; or (vi) Side scuttle of the non-opening type. (2) Heel angle. The maximum angle of heel must not exceed 25 degrees, except that this angle may be increased to 30 degrees if no deck...

46 CFR 172.065 - Damage stability.

Code of Federal Regulations, 2010 CFR

2010-10-01

... of sinkage, heel, and trim, must be below the lower edge of an opening through which progressive... sliding watertight door; or (vi) Side scuttle of the non-opening type. (2) Heel angle. The maximum angle of heel must not exceed 25 degrees, except that this angle may be increased to 30 degrees if no deck...

Open-loop GPS signal tracking at low elevation angles from a ground-based observation site

NASA Astrophysics Data System (ADS)

Beyerle, Georg; Zus, Florian

2016-04-01

For more than a decade space-based global navigation satellite system (GNSS) radio occultation (RO) observations are used by meteorological services world-wide for their numerical weather prediction models. In addition, climate studies increasingly rely on validated GNSS-RO data sets of atmospheric parameters. GNSS-RO profiles typically cover an altitude range from the boundary layer up to the upper stratosphere; their highest accuracy and precision, however, are attained at the tropopause level. In the lower troposphere, multipath ray propagation tend to induce signal amplitude and frequency fluctuations which lead to the development and implementation of open-loop signal tracking methods in GNSS-RO receiver firmwares. In open-loop mode the feed-back values for the carrier tracking loop are derived not from measured data, but from a Doppler frequency model which usually is extracted from an atmospheric climatology. In order to ensure that this receiver-internal parameter set, does not bias the carrier phase path observables, dual-channel open-loop GNSS-RO signal tracking was suggested. Following this proposal the ground-based "GLESER" (GPS low-elevation setting event recorder) campaign was established. Its objective was to disproof the existence of model-induced frequency biases using ground-based GPS observations at very low elevation angles. Between January and December 2014 about 2600 validated setting events, starting at geometric elevation angles of +2° and extending to -1°… - 1.5°, were recorded by the single frequency "OpenGPS" GPS receiver at a measurement site located close to Potsdam, Germany (52.3808°N, 13.0642°E). The study is based on the assumption that these ground-based observations may be used as proxies for space-based RO measurements, even if the latter occur on a one order of magnitude faster temporal scale. The "GLESER" data analysis shows that the open-loop Doppler model has negligible influence on the derived frequency profile provided signal-to-noise density ratios remain above about 30 dB Hz. At low signal levels, however, the dual-channel open-loop design, which tracks the same signal using two Doppler models separated by a 10 Hz offset, reveals a notable bias. A significant fraction of this bias is caused by frequency aliasing. The receiver's dual-channel setup, however, allows for unambiguous identification of the affected observation samples. Finally, the repeat patterns in terms of azimuth angle of the GPS orbit traces reveals characteristic signatures in both, signal amplitude and Doppler frequency with respect to the topography close to the observation site. On the other hand, mean vertical refractivity gradients extracted from ECMWF meteorological fields exhibit moderate correlations with observed signal amplitude fluctuations at negative elevation angles emphasizing the information content of low-elevation GPS signals with respect to the atmospheric state in the boundary layer.

Biomarkers in primary open angle glaucoma.

PubMed

Kokotas, Haris; Kroupis, Christos; Chiras, Dimitrios; Grigoriadou, Maria; Lamnissou, Klea; Petersen, Michael B; Kitsos, George

2012-12-01

Glaucoma, a leading cause of blindness worldwide, is currently defined as a disturbance of the structural or functional integrity of the optic nerve that causes characteristic atrophic changes in the optic nerve, which may lead to specific visual field defects over time. This disturbance usually can be arrested or diminished by adequate lowering of intraocular pressure (IOP). Glaucoma can be divided roughly into two main categories, ‘ open angle ’ and ‘ closed angle ’ glaucoma.Open angle, chronic glaucoma tends to progress at a slower rate and patients may not notice loss of vision until the disease has progressed significantly. Primary open angle glaucoma(POAG) is described distinctly as a multifactorial optic neuropathy that is chronic and progressive with a characteristic acquired loss of optic nerve fibers. Such loss develops in the presence of open anterior chamber angles, characteristic visual field abnormalities, and IOP that is too high for the healthy eye. It manifests by cupping and atrophy of the optic disc, in the absence of other known causes of glaucomatous disease. Several biological markers have been implicated with the disease. The purpose of this study was to summarize the current knowledge regarding the non-genetic molecular markers which have been predicted to have an association with POAG but have not yet been validated.

A simple three dimensional wide-angle beam propagation method

NASA Astrophysics Data System (ADS)

Ma, Changbao; van Keuren, Edward

2006-05-01

The development of three dimensional (3-D) waveguide structures for chip scale planar lightwave circuits (PLCs) is hampered by the lack of effective 3-D wide-angle (WA) beam propagation methods (BPMs). We present a simple 3-D wide-angle beam propagation method (WA-BPM) using Hoekstra’s scheme along with a new 3-D wave equation splitting method. The applicability, accuracy and effectiveness of our method are demonstrated by applying it to simulations of wide-angle beam propagation and comparing them with analytical solutions.

A simple three dimensional wide-angle beam propagation method.

PubMed

Ma, Changbao; Van Keuren, Edward

2006-05-29

The development of three dimensional (3-D) waveguide structures for chip scale planar lightwave circuits (PLCs) is hampered by the lack of effective 3-D wide-angle (WA) beam propagation methods (BPMs). We present a simple 3-D wide-angle beam propagation method (WA-BPM) using Hoekstra's scheme along with a new 3-D wave equation splitting method. The applicability, accuracy and effectiveness of our method are demonstrated by applying it to simulations of wide-angle beam propagation and comparing them with analytical solutions.

The Influence of Structure Heights and Opening Angles of Micro- and Nanocones on the Macroscopic Surface Wetting Properties

NASA Astrophysics Data System (ADS)

Schneider, Ling; Laustsen, Milan; Mandsberg, Nikolaj; Taboryski, Rafael

2016-02-01

We discuss the influence of surface structure, namely the height and opening angles of nano- and microcones on the surface wettability. We show experimental evidence that the opening angle of the cones is the critical parameter on sample superhydrophobicity, namely static contact angles and roll-off angles. The textured surfaces are fabricated on silicon wafers by using a simple one-step method of reactive ion etching at different processing time and gas flow rates. By using hydrophobic coating or hydrophilic surface treatment, we are able to switch the surface wettability from superhydrophilic to superhydrophobic without altering surface structures. In addition, we show examples of polymer replicas (polypropylene and poly(methyl methacrylate) with different wettability, fabricated by injection moulding using templates of the silicon cone-structures.

Wide-angle vision for road views

NASA Astrophysics Data System (ADS)

Huang, F.; Fehrs, K.-K.; Hartmann, G.; Klette, R.

2013-03-01

The field-of-view of a wide-angle image is greater than (say) 90 degrees, and so contains more information than available in a standard image. A wide field-of-view is more advantageous than standard input for understanding the geometry of 3D scenes, and for estimating the poses of panoramic sensors within such scenes. Thus, wide-angle imaging sensors and methodologies are commonly used in various road-safety, street surveillance, street virtual touring, or street 3D modelling applications. The paper reviews related wide-angle vision technologies by focusing on mathematical issues rather than on hardware.

Crustal Structure of the Ionian Basin and Eastern Sicily Margin: Results From a Wide-Angle Seismic Survey

NASA Astrophysics Data System (ADS)

Dellong, David; Klingelhoefer, Frauke; Kopp, Heidrun; Graindorge, David; Margheriti, Lucia; Moretti, Milena; Murphy, Shane; Gutscher, Marc-Andre

2018-03-01

In the Ionian Sea (central Mediterranean) the slow convergence between Africa and Eurasia results in the formation of a narrow subduction zone. The nature of the crust of the subducting plate remains debated and could represent the last remnants of the Neo-Tethys ocean. The origin of the Ionian basin is also under discussion, especially concerning the rifting mechanisms as the Malta Escarpment could represent a remnant of this opening. This subduction retreats toward the south-east (motion occurring since the last 35 Ma) but is confined to the narrow Ionian basin. A major lateral slab tear fault is required to accommodate the slab roll-back. This fault is thought to propagate along the eastern Sicily margin but its precise location remains controversial. This study focuses on the deep crustal structure of the eastern Sicily margin and the Malta Escarpment. We present two two-dimensional P wave velocity models obtained from forward modeling of wide-angle seismic data acquired onboard the R/V Meteor during the DIONYSUS cruise in 2014. The results image an oceanic crust within the Ionian basin as well as the deep structure of the Malta Escarpment, which presents characteristics of a transform margin. A deep and asymmetrical sedimentary basin is imaged south of the Messina strait and seems to have opened between the Calabrian and Peloritan continental terranes. The interpretation of the velocity models suggests that the tear fault is located east of the Malta Escarpment, along the Alfeo fault system.

The use of new facility by means internal balance with sting support for wide range Angle of Attack aircraft

NASA Astrophysics Data System (ADS)

Subagyo; Daryanto, Yanto; Risnawan, Novan

2018-04-01

The development of facilities for the testing of wide range angle of attack aircraft in the wind tunnel at subsonic regime has done and implemented. Development required to meet the test at an angle of attack from -20 ° to 40 °. Testing the wide range angle of attack aircraft with a wide variation of the angle of attack become important needs. This can be done simply by using the sting support-equipped by internal balance to measure the forces and moments component aerodynamics. The results of development and use on the wide range angle of attack aircraft testing are aerodynamics characteristics in the form of the coefficient three components forces and the three components of the moment. A series of test aircraft was successfully carried out and the results are shown in the form of graphs of characteristic of aerodynamics at wind speed 70 m/s.

Effect of triggering angles on the crushing mechanisms of hybrid woven kenaf/aluminum hollow cylinders

NASA Astrophysics Data System (ADS)

Ismail, Al Emran; Mat Noor, Fazimah; Mohamad, Zaleha; Amran Madlan, Mohd; Zulafif Rahim, M.; Rasidi Ibrahim, M.; Ahmad, Sufizar; Nasrull Abdol Rahman, Mohd; Salleh, Salihatun Md; Sadikin, Azmahani; Mahzan, Shahruddin; Nor, Nik Hisyamudin Muhd

2017-10-01

This paper presents the effect of triggering angles constructed on the top of hybrid woven kenaf/aluminium hollow cylinders on the energy absorption performances. The crushing performances of aluminium tubes can be found widely in open literature. However, lack number of work on the hybridizing the aluminium tubes with woven kenaf fibre is found. Woven kenaf mats are produced and bathed with polymeric resin before they are wrapped around the aluminium tubes twice. Different fibre orientations, ±θ° are used where θ = 0, 15, 30 and 45. Once the hybrid composite hardened, one of their end are chamfered using different angles of 0°, 30°, 45° and 60°. The tubes are quasi-statically compressed in order to obtain their force-displacement responses and crashworthiness parameters are extracted and discussed with the relation of fibre orientations and chamfering angles. It is found that the chamfering angles are only affected the force-displacement curves during the first stage of elastic deformation whereas there is no obvious effect in the second stage. However, varying the fibre orientations are slightly increased the force-displacement curves especially when the fibre is orientated with 30°. Based on the fracture mechanism observations, most of composite experienced large fragmentation indicating that the composites absorbed the crushing energy ineffectively.

Geometrically Thick Obscuration by Radiation-driven Outflow from Magnetized Tori of Active Galactic Nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, Chi-Ho; Krolik, Julian H.

2017-07-01

Near-Eddington radiation from active galactic nuclei (AGNs) has significant dynamical influence on the surrounding dusty gas, plausibly furnishing AGNs with geometrically thick obscuration. We investigate this paradigm with radiative magnetohydrodynamics simulations. The simulations solve the magnetohydrodynamics equations simultaneously with the infrared (IR) and ultraviolet (UV) radiative transfer (RT) equations; no approximate closure is used for RT. We find that our torus, when given a suitable sub-Keplerian angular momentum profile, spontaneously evolves toward a state in which its opening angle, density distribution, and flow pattern change only slowly. This “steady” state lasts for as long as there is gas resupply towardmore » the inner edge. The torus is best described as a midplane inflow and a high-latitude outflow. The outflow is launched from the torus inner edge by UV radiation and expands in solid angle as it ascends; IR radiation continues to drive the wide-angle outflow outside the central hole. The dusty outflow obscures the central source in soft X-rays, the IR, and the UV over three-quarters of solid angle, and each decade in column density covers roughly equal solid angle around the central source; these obscuration properties are similar to what observations imply.« less

Effect of aperture geometry on heat transfer in tilted partially open cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elsayed, M.M.; Chakroun, W.

1999-11-01

Heat transfer in cavities is receiving increasing attention because of the various applications in engineering; e.g., passive solar heating, energy conservation in buildings, solar concentrating receivers, and electronic equipment. Here, convection from a square, tilted partially open cavity was investigated experimentally. The experiment was carried out to study the effect of the aperture geometry on the heat transfer between the cavity and the surrounding air. Four different geometrical arrangements for the opening were investigated: (1) high wall slit, (2) low wall slit, (3) centered wall slit, and (4) uniform wall slots. Each opening arrangement was studied at opening ratios (i.e.,more » ratio of opening height to cavity height) of 0.25, 0.5, and 0.75. The average heat transfer coefficient between the cavity and the surrounding air was estimated for each geometrical arrangement for tilt angles ranging from {minus}90 deg to +90 deg with increments of 15 deg and at a constant heat flux Grashof number of 5.5 x 10{sup 8}. The results showed that for tilt angles between 90 and 75 deg, the heat transfer coefficient has a small value that is independent of the geometrical arrangement of the opening. The value of the heat transfer coefficient increases sharply with decreasing tilt angle until an angle value of zero degrees is reached. The increase in the heat transfer coefficient continues in the negative range of tilt angle but not in the same rate as in the positive range of the tilt angle. The uniform slot arrangement gave in general higher heat transfer coefficient than the other three arrangements of the opening. Large differences in the heat transfer coefficient were observed between the high and the low wall slits where the high wall slit is found to transfer more heat to the surroundings than the low wall slit. Correlations were developed to predict the average Nusselt number of the cavity in terms of the opening ratio and the cavity tilt angle for cavities with high wall slit, low wall slit, centered wall slit, and the uniform wall slots.« less

Anatomical features of skull base and oral cavity: a pilot study to determine the accessibility of the sella by transoral robotic-assisted surgery.

PubMed

Amelot, Aymeric; Trunet, Stephanie; Degos, Vincent; André, Olivier; Dionnet, Aurore; Cornu, Philippe; Hans, Stéphane; Chauvet, Dorian

2015-10-01

The role of transoral robotic surgery (TORS) in the skull base emerges and represents the natural progression toward miniinvasive resections in confined spaces. The accessibility of the sella via TORS has been recently described on fresh human cadavers. An anatomic study is mandatory to know if this approach would be feasible in the majority of patients regardless of their oral morphological features. From 30 skull base CT scans from patients who were asked to open their mouth as wide as they can, we measured specific dimensions of the oral cavity and the skull base, such as length of the palate, mouth opening and distance from the sella to the palate. All data were acquired on a sagittal midline plane and on a 25° rotation plane, which simulated the axis of the robotic instruments. Looking at the projection of the dental palatine line on the sella, we studied possible predictive factors of sellar accessibility and tried to bring objective data for surgical feasibility. We also proposed an angle α to study the working angle at the skull base. We observed that the maximal mouth opening was a good predictive factor of sellar accessibility by TORS (p < 0.05). The mouth aperture threshold value for a good sensitivity, over 80 %, was comparable to the mean value of mouth opening in our series, 38.9 and 39.4 mm respectively. Moreover, we showed a statistically significant increase of the working angle α at the skull base comparing the lateral access to the midline one (p < 0.05). This seemed to quantitatively demonstrate that the robotic arms placed at the labial commissure of the mouth can reach the sella. From these anatomical features and previous cadaveric dissections, we assume that TORS may be feasible on a majority of patients to remove pituitary adenomas.

[Magnetotherapy designed to affect cervical sympathetic ganglia for the treatment of patients with primary open-angle glaucoma].

PubMed

Veselova, E V; Kamenskikh, T G; Raĭgorodkiĭ, Iu M; Kolbenev, I O; Myshkina, E S

2010-01-01

The traveling magnetic field was used to treat primary open-angle glaucoma. The field was applied to the projection of cervical sympathetic ganglia of the patients. Hemodynamic parameters of posterior short ciliary arteries and central retinal artery were analysed along with visual evoked potentials, visual field limits, and visual acuity. It was shown that magnetotherapy with the use of an AMO-ATOS apparatus produces better clinical results in patients with stage I and II primary open-angle glaucoma compared with medicamentous therapy (intake of trental tablets).

46 CFR 174.207 - Damaged stability criteria.

Code of Federal Regulations, 2011 CFR

2011-10-01

... sinkage, heel, and trim, must be below the lower edge of an opening through which progressive flooding may... of this subpart; or (v) Side scuttle of the non-opening type. (2) Angle of heel. The angle of heel...

s95-16445

NASA Image and Video Library

2014-08-07

S95-16445 (13-22 July 1995) --- A wide angle view from the rear shows activity in the new Mission Control Center (MCC), opened for operation and dedicated during the STS-70 mission. The Space Shuttle Discovery was just passing over Florida at the time this photo was taken (note mercator map and TV scene on screens). The new MCC, developed at a cost of about 50 million, replaces the main-frame based, NASA-unique design of the old Mission Control with a standard workstation-based, local area network system commonly in use today.

Lone Propeller

NASA Image and Video Library

2017-09-15

This view of Saturn's A ring features a lone "propeller" -- one of many such features created by small moonlets embedded in the rings as they attempt, unsuccessfully, to open gaps in the ring material. The image was taken by NASA's Cassini spacecraft on Sept. 13, 2017. It is among the last images Cassini sent back to Earth. The view was taken in visible light using the Cassini spacecraft wide-angle camera at a distance of 420,000 miles (676,000 kilometers) from Saturn. Image scale is 2.3 miles (3.7 kilometers). https://photojournal.jpl.nasa.gov/catalog/PIA21894

High prevalence of narrow angles among Chinese-American glaucoma and glaucoma suspect patients.

PubMed

Seider, Michael I; Pekmezci, Melike; Han, Ying; Sandhu, Simi; Kwok, Shiu Y; Lee, Roland Y; Lin, Shan C

2009-01-01

To evaluate the prevalence of gonioscopically narrow angles in a Chinese-American population with glaucoma or glaucoma suspicion. Charts from all Chinese-American patients seen in a comprehensive ophthalmology clinic in the Chinatown district of San Francisco in 2002 were reviewed. One eye from each patient with glaucoma or glaucoma suspicion that met inclusion criteria was included (n=108). Data were collected for sex, age, race (self-declared), refraction (spherical equivalent), intraocular pressure, gonioscopy, and vertical cup-to-disk ratio. Sixty percent (n=65) of Chinese-American eyes with glaucoma or glaucoma suspicion had gonioscopically narrow angles (Shaffer grade < or = 2 in 3 or more quadrants). Those with narrow angles were significantly older (P=0.004) than their open angle counterparts, but the 2 groups did not differ in terms of sex, refraction, intraocular pressure, or cup-to-disk ratio (all, P > or = 0.071). In a multivariate model including age, sex, and refraction as predictors of angle grade (open or narrow), only age was a significant predictor of angle grade (P=0.004). A large proportion of Chinese-Americans in our study population with glaucoma or glaucoma suspicion had gonioscopically narrow angles. In multivariate analysis, patients with narrow angles were older than those with open angles but did not differ from them in terms of sex or refraction. Continued evaluation of angle closure glaucoma risk among Chinese-Americans is needed.

Assessment of morphological and anatomical characteristics of mental foramen using cone beam computed tomography.

PubMed

Goyushov, Samir; Tözüm, Melek Didem; Tözüm, Tolga Fikret

2018-05-25

To determine the shape, position, vertical height, surrounding bone characteristics, and opening angle of mental foramen (MF) using dental cone beam computed tomography (CBCT). A retrospective study was performed on 663 patients. CBCT records analyzed for the shape, position, and surrounding bone measurements of the MF using Simplant 3D software (Hasselt, Belgium). Opening angle of MF was also assessed. Kruskal-Wallis and Mann-Whitney U tests were employed to test significant differences between parameters, genders and ages. All mental foramina were visualized. Regarding location, 49.2% of the MFs were located between first and second premolars, 7.7 distal and 39.7% coincident to the apex of the mandibular second premolar. The mean MF opening angle was 45.4° on the right side, and 45.9° on the left. There were no statistically differences between gender groups with regard to the opening angle degrees. This study may provide useful information about variations in the position, shape and size, angle of mental foramen, which may help the practitioners to perform safer mental nerve blocks and surgical procedures.

MHD effects on heat transfer and entropy generation of nanofluid flow in an open cavity

NASA Astrophysics Data System (ADS)

Mehrez, Zouhaier; El Cafsi, Afif; Belghith, Ali; Le Quéré, Patrick

2015-01-01

The present numerical work investigates the effect of an external oriented magnetic field on heat transfer and entropy generation of Cu-water nanofluid flow in an open cavity heated from below. The governing equations are solved numerically by the finite-volume method. The study has been carried out for a wide range of solid volume fraction 0≤φ≤0.06, Hartmann number 0≤Ha≤100, Reynolds number 100≤Re≤500 and Richardson number 0.001≤Ri≤1 at three inclination angles of magnetic field γ: 0°, 45° and 90°. The numerical results are given by streamlines, isotherms, average Nusselt number, average entropy generation and Bejan number. The results show that flow behavior, temperature distribution, heat transfer and entropy generation are strongly affected by the presence of a magnetic field. The average Nusselt number and entropy generation, which increase by increasing volume fraction of nanoparticles, depend mainly on the Hartmann number and inclination angle of the magnetic field. The variation rates of heat transfer and entropy generation while adding nanoparticles or applying a magnetic field depend on the Richardson and Reynolds numbers.

Synthetic strategy for preparing chiral double-semicrystalline polyether block copolymers

DOE PAGES

McGrath, Alaina J.; Shi, Weichao; Rodriguez, Christina G.; ...

2014-12-11

Here, we report an effective strategy for the synthesis of semi-crystalline block copolyethers with well-defined architecture and stereochemistry. As an exemplary system, triblock copolymers containing either atactic (racemic) or isotactic ( R or S) poly(propylene oxide) end blocks with a central poly(ethylene oxide) mid-block were prepared by anionic ring-opening procedures. Stereochemical control was achieved by an initial hydrolytic kinetic resolution of racemic terminal epoxides followed by anionic ring-opening polymerization of the enantiopure monomer feedstock. The resultant triblock copolymers were highly isotactic (meso triads [ mm]% ~ 90%) with optical microscopy, differential scanning calorimetry, wide angle x-ray scattering and small anglemore » x-ray scattering being used to probe the impact of the isotacticity on the resultant polymer and hydrogel properties.« less

Agreement between Gonioscopic Examination and Swept Source Fourier Domain Anterior Segment Optical Coherence Tomography Imaging

PubMed Central

Nguyen, Donna; Minnal, Vandana R.

2016-01-01

Purpose. To evaluate interobserver, intervisit, and interinstrument agreements for gonioscopy and Fourier domain anterior segment optical coherence tomography (FD ASOCT) for classifying open and narrow angle eyes. Methods. Eighty-six eyes with open or narrow anterior chamber angles were included. The superior angle was classified open or narrow by 2 of 5 glaucoma specialists using gonioscopy and imaged by FD ASOCT in the dark. The superior angle of each FD ASOCT image was graded as open or narrow by 2 masked readers. The same procedures were repeated within 6 months. Kappas for interobserver and intervisit agreements for each instrument and interinstrument agreements were calculated. Results. The mean age was 50.9 (±18.4) years. Interobserver agreements were moderate to good for both gonioscopy (0.57 and 0.69) and FD ASOCT (0.58 and 0.75). Intervisit agreements were moderate to excellent for both gonioscopy (0.53 to 0.86) and FD ASOCT (0.57 and 0.85). Interinstrument agreements were fair to good (0.34 to 0.63), with FD ASOCT classifying more angles as narrow than gonioscopy. Conclusions. Both gonioscopy and FD ASOCT examiners were internally consistent with similar interobserver and intervisit agreements for angle classification. Agreement between instruments was fair to good, with FD ASOCT classifying more angles as narrow than gonioscopy. PMID:27990300

Real-time inverse kinematics for the upper limb: a model-based algorithm using segment orientations.

PubMed

Borbély, Bence J; Szolgay, Péter

2017-01-17

Model based analysis of human upper limb movements has key importance in understanding the motor control processes of our nervous system. Various simulation software packages have been developed over the years to perform model based analysis. These packages provide computationally intensive-and therefore off-line-solutions to calculate the anatomical joint angles from motion captured raw measurement data (also referred as inverse kinematics). In addition, recent developments in inertial motion sensing technology show that it may replace large, immobile and expensive optical systems with small, mobile and cheaper solutions in cases when a laboratory-free measurement setup is needed. The objective of the presented work is to extend the workflow of measurement and analysis of human arm movements with an algorithm that allows accurate and real-time estimation of anatomical joint angles for a widely used OpenSim upper limb kinematic model when inertial sensors are used for movement recording. The internal structure of the selected upper limb model is analyzed and used as the underlying platform for the development of the proposed algorithm. Based on this structure, a prototype marker set is constructed that facilitates the reconstruction of model-based joint angles using orientation data directly available from inertial measurement systems. The mathematical formulation of the reconstruction algorithm is presented along with the validation of the algorithm on various platforms, including embedded environments. Execution performance tables of the proposed algorithm show significant improvement on all tested platforms. Compared to OpenSim's Inverse Kinematics tool 50-15,000x speedup is achieved while maintaining numerical accuracy. The proposed algorithm is capable of real-time reconstruction of standardized anatomical joint angles even in embedded environments, establishing a new way for complex applications to take advantage of accurate and fast model-based inverse kinematics calculations.

Glaucoma anterior chamber morphometry based on optical Scheimpflug images.

PubMed

Alonso, Ruiz Simonato; Ambrósio Junior, Renato; Paranhos Junior, Augusto; Sakata, Lisandro Massanori; Ventura, Marcelo Palis

2010-01-01

To compare the performance of gonioscopy and noncontact morphometry with anterior chamber tomography (High Resolution Pentacam - HR) using optical Scheimpflug images in the evaluation of the anterior chamber angle (ACA). Transversal study. 112 eyes from 74 subjects evaluated at the Glaucoma Department, Fluminense Federal University, underwent gonioscopy and Pentacam HR. Using gonioscopy, the ACA was graded using the Shaffer Classification (SC) by a single experienced examiner masked to the Pentacam HR findings. Narrow angle was determined in eyes in which the posterior trabecular meshwork could not be seen in two or more quadrants on non-indentation gonioscopy (SC Grade 2 or less). Pentacam HR images of the nasal and temporal quadrants were evaluated by custom software to automatically obtain anterior chamber measurements, such as: anterior chamber angle (ACA), anterior chamber volume (ACV) and anterior chamber depth (ACD). Based on gonioscopy results, 74 (60.07%) eyes of patients classified as open-angle (SC 3 and 4) and 38 (33.93%) eyes of patients classified as narrow-angle (SC 1 and 2). Noncontact morphometry with Scheimpflug images revealed a mean ACA of 39.20 ± 5.31 degrees for open-angle and 21.18 ± 7.98 degrees for narrow-angle. The open-angle group showed significant greater ACV and ACD values when compared to narrow-angle group (ACV of 193 ± 36 mm³ vs. 90 ± 25 mm³, respectively, p<0.001; and ACD of 3,09 ± 0,42 mm vs. 1,55 ± 0,64 mm, respectively, p<0.0001.). In screening eyes with open-angle and narrow-angle with the Pentacam ACA of 20º (SC Grade 2) using the ROC curves, the analysis showed 52.6% of sensitivity and 100% of specificity. The Pentacam showed ability in detecting eyes at risk for angle closure analyzing ACV and ACD.

Peripapillary schisis in open-angle glaucoma.

PubMed

Dhingra, N; Manoharan, R; Gill, S; Nagar, M

2017-03-01

PurposeTo report clinical features, topographic findings and outcome of 10 eyes with peripapillary schisis in open-angle glaucoma.Patients and methodsA retrospective review of patients with open-angle glaucoma who were noted to have peripapillary schisis on optical coherence tomography (OCT) were included. Serial peripapillary and macula infrared and OCT images, visual acuity, visual fields, and schisis appearance were reviewed.ResultsTen eyes of nine patients with open-angle glaucoma were detected to have the presence of peripapillary schisis. Nerve fibre layer schisis was detected in all eyes and one eye had an associated macular schisis. None of the eyes had an acquired pit of the optic nerve or pathological myopia. The mean intraocular pressures at detection was 18.3±4.3 mm Hg and the schisis resolved in four eyes after a mean follow-up of 21.2±8.8 months. Visual field worsening was noted in 4 of the 10 eyes and the resolution of schisis resulted in significant reduction in the retinal nerve fibre layer (RNFL) thickness.ConclusionsPeripapillary schisis detected during the normal course of open-angle glaucoma can resolve spontaneously and rarely involves the macula. Its resolution leads to reduction in RNFL thickness; therefore, caution is advised while interpreting serial scans.

Extending the Utility of the Parabolic Approximation in Medical Ultrasound Using Wide-Angle Diffraction Modeling.

PubMed

Soneson, Joshua E

2017-04-01

Wide-angle parabolic models are commonly used in geophysics and underwater acoustics but have seen little application in medical ultrasound. Here, a wide-angle model for continuous-wave high-intensity ultrasound beams is derived, which approximates the diffraction process more accurately than the commonly used Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation without increasing implementation complexity or computing time. A method for preventing the high spatial frequencies often present in source boundary conditions from corrupting the solution is presented. Simulations of shallowly focused axisymmetric beams using both the wide-angle and standard parabolic models are compared to assess the accuracy with which they model diffraction effects. The wide-angle model proposed here offers improved focusing accuracy and less error throughout the computational domain than the standard parabolic model, offering a facile method for extending the utility of existing KZK codes.

Assessment of narrow angles by gonioscopy, Van Herick method and anterior segment optical coherence tomography.

PubMed

Park, Seong Bae; Sung, Kyung Rim; Kang, Sung Yung; Jo, Jung Woo; Lee, Kyoung Sub; Kook, Michael S

2011-07-01

To evaluate anterior chamber (AC) angles using gonioscopy, Van Herick technique and anterior segment optical coherence tomography (AS-OCT). One hundred forty-eight consecutive subjects were enrolled. The agreement between any two of three diagnostic methods, gonioscopy, AS-OCT and Van Herick, was calculated in narrow-angle patients. The area under receiver-operating characteristic curves (AUC) for discriminating between narrow and open angles determined by gonioscopy was calculated in all participants for AS-OCT parameter angle opening distance (AOD), angle recess area, trabecular iris surface area and anterior chamber depth (ACD). As a subgroup analysis, capability of AS-OCT parameters for detecting angle closure defined by AS-OCT was assessed in narrow-angle patients. The agreement between the Van Herick method and gonioscopy in detecting angle closure was excellent in narrow angles (κ = 0.80, temporal; κ = 0.82, nasal). However, agreement between gonioscopy and AS-OCT and between the Van Herick method and AS-OCT was poor (κ = 0.11-0.16). Discrimination capability of AS-OCT parameters between open and narrow angles determined by gonioscopy was excellent for all AS-OCT parameters (AUC, temporal: AOD500 = 0.96, nasal: AOD500 = 0.99). The AUCs for detecting angle closure defined by AS-OCT image in narrow angle subjects was good for all AS-OCT parameters (AUC, 0.80-0.94) except for ACD (temporal: ACD = 0.70, nasal: ACD = 0.63). Assessment of narrow angles by gonioscopy and the Van Herick technique showed good agreement, but both measurements revealed poor agreement with AS-OCT. The angle closure detection capability of AS-OCT parameters was excellent; however, it was slightly lower in ACD.

High Prevalence of Narrow Angles among Chinese-American Glaucoma and Glaucoma Suspect Patients

PubMed Central

Seider, Michael I; Pekmezci, Melike; Han, Ying; Sandhu, Simi; Kwok, Shiu Y; Lee, Roland Y; Lin, Shan C

2009-01-01

Purpose To evaluate the prevalence of gonioscopically narrow angles in a Chinese-American population with glaucoma or glaucoma suspicion. Patients and Methods Charts from all Chinese-American patients seen in a comprehensive ophthalmology clinic in the Chinatown district of San Francisco in 2002 were reviewed. One eye from each patient with glaucoma or glaucoma suspicion that met inclusion criteria was included (n=108). Data was collected for gender, age, race (self-declared), refraction (spherical equivalent), intraocular pressure (IOP), gonioscopy and vertical cup-to-disk ratio (CDR). Results Sixty percent (n=65) of Chinese-American eyes with glaucoma or glaucoma suspicion had gonioscopically narrow angles (Shaffer grade ≤2 in three or more quadrants). Those with narrow angles were significantly older (P=0.004) than their open angle counterparts, but the two groups did not differ in terms of gender, refraction, IOP or CDR (all, P≥0.071). In a multivariate model including age, gender and refraction as predictors of angle grade (open or narrow), only age was a significant predictor of angle grade (P=0.004). Conclusions A large proportion of Chinese-Americans in our study population with glaucoma or glaucoma suspicion had gonioscopically narrow angles. In multivariate analysis, patients with narrow angles were older than those with open angles but did not differ from them in terms of gender or refraction. Continued evaluation of angle closure glaucoma risk among Chinese-Americans is needed. PMID:19826385

Comparison of a technique using a new percutaneous osteosynthesis device with conventional open surgery for displaced patella fractures in a randomized controlled trial.

PubMed

Luna-Pizarro, Daniel; Amato, Dante; Arellano, Francisco; Hernández, Armando; López-Rojas, Pablo

2006-09-01

To compare the percutaneous patellar osteosynthesis system (PPOS) technique with open surgery for patella fractures. Randomized controlled trial. Referral orthopedic and trauma center. Fifty-three patients with displaced patellar fractures. Stabilization and fixation of patellar fractures with PPOS or open surgery. Knee-flexion and -extension angles, pain, surgical time, and assessment of knee function based on the Knee Society Clinical Rating Scale (KSCRS). Comparison of PPOS and open-surgery groups at 4 weeks showed the following: pain, 3.7 +/- 1.6 versus 6.2 +/- 1.4 arbitrary units, P < 0.001; flexion angle, 46 +/- 20.7 versus 12.7 +/- 6.0 degrees, P < 0.001; extension angle, -2.5 versus -3.8 degrees, P < 0.001. At 8 weeks, the following was demonstrated: pain, 1.3 +/- 1.6 versus 4.1 +/- 2.1 arbitrary units, P < 0.001; flexion angle, 87 +/- 17.3 versus 34 +/- 26 degrees, P < 0.001; extension angle, 0 versus -3 degrees, P < 0.001. Surgical time was 35.3 +/- 7.8 versus 66.2 +/- 14.1 minutes, P < 0.001. KSCRS assessment was 84 +/- 4 versus 70 +/- 8, P < 0.001 at 8 weeks; 85 +/- 2 versus 73 +/- 8, P < 0.001 at 12 months; and 85 +/- 1 versus 82 +/- 7, P = 0.246 at 24 months. Frequency of total complications (infections, fragment displacement, and wire-related pain) was significantly lower in the PPOS than in the open-surgery group (P < 0.02). PPOS for patella fractures was associated with shorter surgical time, less pain, better mobility angles, higher functional score up to 2 years, and a lower incidence of complications than open surgery.

Regional distribution of circumferential residual strains in the human aorta according to age and gender.

PubMed

Sokolis, Dimitrios P; Savva, Giannis D; Papadodima, Stavroula A; Kourkoulis, Stavros K

2017-03-01

The biomechanical response of the human aorta varies with axial location, but little is known about the respective variation of residual strains. Such data are available for common lab animals, but in the traditional opening angle measurement the aorta is considered as an ideal cylinder and average residual strains are measured, so that the spatial variations of local residual strains are not determined. The present study provides opening angle and residual strain data throughout the course and around the circumference of the aorta harvested during autopsy. Opening angle showed notable topographical variation; the highest value was at the top of aortic arch, declining abruptly toward the ascending aorta and to a near-constant value in the descending aorta, and rising in the abdominal aorta. The variation of curvature and of external but not internal residual stretch resembled that of opening angle. Extensive residual stress and wall thickness differences were evidenced among quadrants, with the more pre-stressed being also the thicker quadrants. Gender had overall minor effects, but aging led to increased parameters, occurring earlier in the distal aorta but at later stages becoming predominant proximally. Differences in caliber were pronounced in older subjects, unlike those in opening angle, residual stretches, and thickness that were striking in middle-aged subjects. By contrast, curvature decreased with aging in relation to the smaller percentwise opening angle differences. Detailed knowledge of the zero-stress/no-load geometry of the human aortic wall is critical for an in-depth understanding of aortic physiology, while providing the basis for comparison with disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gonioscopy-assisted Transluminal Trabeculotomy: An Ab Interno Circumferential Trabeculotomy: 24 Months Follow-up.

PubMed

Grover, Davinder S; Smith, Oluwatosin; Fellman, Ronald L; Godfrey, David G; Gupta, Aditi; Montes de Oca, Ildamaris; Feuer, William J

2018-05-01

The purpose of this study was to provide 24-month follow-up on surgical success and safety of an ab interno circumferential 360-degree trabeculotomy. Chart review of patients who underwent a gonioscopy-assisted transluminal trabeculotomy (GATT) procedure was performed by 4 of the authors (D.S.G., O.S., R.L.F., and D.G.G.). The surgery was performed in adults with various types of open-angle glaucoma with preoperative intraocular pressures (IOPs) of ≥18 mm Hg. In total, 198 patients aged 24 to 89 years underwent the GATT procedure with at least 18 months follow-up. Patients with primary open-angle glaucoma had an average IOP decrease of 9.2 mm Hg at 24 months with an average decrease of 1.43 glaucoma medications. The mean percentage of IOP decrease in these primary open-angle glaucoma groups at 24 months was 37.3%. In secondary open-angle glaucoma, at 24 months there was an average decrease in IOP of 14.1 mm Hg on an average of 2.0 fewer medications. The mean percentage of IOP decrease in the secondary open-angle glaucoma groups at 24 months was 49.8%. The cumulative proportion of failure at 24 months ranged from 0.18 to 0.48, depending on the group. In all 6 study groups, at all 5 postoperative time points (3, 6, 12, 18, and 24 mo) the mean IOP and reduction in glaucoma medications was significantly reduced from baseline (P<0.001) with the exception of one time point. The 24-month results demonstrate that GATT is relatively safe and effective in treating various forms of open-angle glaucoma. The long-term results for GATT are relatively equivalent to those previously reported for GATT and ab externo trabeculotomy studies.

The Frequency of Optical Coherence Tomography Testing in Glaucoma at a Single Academic Medical Center.

PubMed

Griffith, Joseph F; Goldberg, Jeffrey L

2016-03-01

To determine the frequency of optical coherence tomography (OCT) examinations compared with clinical examinations and visual field (VF) tests in patients with 5 types of glaucoma. A retrospective, longitudinal cohort study was conducted of 5154 patients treated between 2003 and 2010 at a single academic medical center. Patients were classified using billing records as having primary open-angle glaucoma, low-tension open-angle glaucoma (NTG), pigmentary open-angle glaucoma, chronic angle-closure glaucoma, or pseudoexfoliation glaucoma. Analysis of variance, χ test, and exact χ test were performed to identify associations between glaucoma type and test frequency. Pigmentary open-angle glaucoma and NTG patients had a higher rate of undergoing at least 2 VFs (94.4%, 94.9%), and chronic angle-closure glaucoma patients had a lower rate of undergoing at least 2 OCTs (25.3%) than all other glaucoma types. NTG patients also had the highest rate of undergoing at least 2 OCTs and at least 2 VFs (36.6%). Overall, the rate of clinical examinations (2.68 examinations/y) exceeded the rates of OCTs (1.39 examinations/y), which exceeded the rate of VF tests (1.24 tests/y). There were no differences in OCT frequency between glaucoma types (0.91 to 1.63 OCTs/y). Within each glaucoma diagnosis, patients had clinical examinations more frequently than OCTs and clinical examinations more frequently than VFs. Primary open-angle glaucoma and pseudoexfoliation glaucoma patients also had OCTs more frequently than VFs. More patients had at least 2 VF tests than at least 2 OCTs (4481 vs. 1679). The relative use of clinical examinations, VF testing, and OCT imaging varies among glaucoma diagnoses.

The Zeldovich approximation and wide-angle redshift-space distortions

NASA Astrophysics Data System (ADS)

Castorina, Emanuele; White, Martin

2018-06-01

The contribution of line-of-sight peculiar velocities to the observed redshift of objects breaks the translational symmetry of the underlying theory, modifying the predicted 2-point functions. These `wide angle effects' have mostly been studied using linear perturbation theory in the context of the multipoles of the correlation function and power spectrum . In this work we present the first calculation of wide angle terms in the Zeldovich approximation, which is known to be more accurate than linear theory on scales probed by the next generation of galaxy surveys. We present the exact result for dark matter and perturbatively biased tracers as well as the small angle expansion of the configuration- and Fourier-space two-point functions and the connection to the multi-frequency angular power spectrum. We compare different definitions of the line-of-sight direction and discuss how to translate between them. We show that wide angle terms can reach tens of percent of the total signal in a measurement at low redshift in some approximations, and that a generic feature of wide angle effects is to slightly shift the Baryon Acoustic Oscillation scale.

Buoyant miscible displacement flow of shear-thinning fluids: Experiments and Simulations

NASA Astrophysics Data System (ADS)

Ale Etrati Khosroshahi, Seyed Ali; Frigaard, Ian

2017-11-01

We study displacement flow of two miscible fluids with density and viscosity contrast in an inclined pipe. Our focus is mainly on displacements where transverse mixing is not significant and thus a two-layer, stratified flow develops. Our experiments are carried out in a long pipe, covering a wide range of flow-rates, inclination angles and viscosity ratios. Density and viscosity contrasts are achieved by adding Glycerol and Xanthan gum to water, respectively. At each angle, flow rate and viscosity ratio are varied and density contrast is fixed. We identify and map different flow regimes, instabilities and front dynamics based on Fr , Re / Frcosβ and viscosity ratio m. The problem is also studied numerically to get a better insight into the flow structure and shear-thinning effects. Numerical simulations are completed using OpenFOAM in both pipe and channel geometries and are compared against the experiments. Schlumberger, NSERC.

Optical superimposed vortex beams generated by integrated holographic plates with blazed grating

NASA Astrophysics Data System (ADS)

Zhang, Xue-Dong; Su, Ya-Hui; Ni, Jin-Cheng; Wang, Zhong-Yu; Wang, Yu-Long; Wang, Chao-Wei; Ren, Fei-Fei; Zhang, Zhen; Fan, Hua; Zhang, Wei-Jie; Li, Guo-Qiang; Hu, Yan-Lei; Li, Jia-Wen; Wu, Dong; Chu, Jia-Ru

2017-08-01

In this paper, we demonstrate that the superposition of two vortex beams with controlled topological charges can be realized by integrating two holographic plates with blazed grating. First, the holographic plate with blazed grating was designed and fabricated by laser direct writing for generating well-separated vortex beam. Then, the relationship between the periods of blazed grating and the discrete angles of vortex beams was systemically investigated. Finally, through setting the discrete angle and different revolving direction of the holographic plates, the composite fork-shaped field was realized by the superposition of two vortex beams in a particular position. The topological charges of composite fork-shaped field (l = 1, 0, 3, and 4) depend on the topological charges of compositional vortex beams, which are well agreed with the theoretical simulation. The method opens up a wide range of opportunities and possibilities for applying in optical communication, optical manipulations, and photonic integrated circuits.

Detecting blind building façades from highly overlapping wide angle aerial imagery

NASA Astrophysics Data System (ADS)

Burochin, Jean-Pascal; Vallet, Bruno; Brédif, Mathieu; Mallet, Clément; Brosset, Thomas; Paparoditis, Nicolas

2014-10-01

This paper deals with the identification of blind building façades, i.e. façades which have no openings, in wide angle aerial images with a decimeter pixel size, acquired by nadir looking cameras. This blindness characterization is in general crucial for real estate estimation and has, at least in France, a particular importance on the evaluation of legal permission of constructing on a parcel due to local urban planning schemes. We assume that we have at our disposal an aerial survey with a relatively high stereo overlap along-track and across-track and a 3D city model of LoD 1, that can have been generated with the input images. The 3D model is textured with the aerial imagery by taking into account the 3D occlusions and by selecting for each façade the best available resolution texture seeing the whole façade. We then parse all 3D façades textures by looking for evidence of openings (windows or doors). This evidence is characterized by a comprehensive set of basic radiometric and geometrical features. The blindness prognostic is then elaborated through an (SVM) supervised classification. Despite the relatively low resolution of the images, we reach a classification accuracy of around 85% on decimeter resolution imagery with 60 × 40 % stereo overlap. On the one hand, we show that the results are very sensitive to the texturing resampling process and to vegetation presence on façade textures. On the other hand, the most relevant features for our classification framework are related to texture uniformity and horizontal aspect and to the maximal contrast of the opening detections. We conclude that standard aerial imagery used to build 3D city models can also be exploited to some extent and at no additional cost for facade blindness characterisation.

Realization of an Ultra-thin Metasurface to Facilitate Wide Bandwidth, Wide Angle Beam Scanning.

PubMed

Bah, Alpha O; Qin, Pei-Yuan; Ziolkowski, Richard W; Cheng, Qiang; Guo, Y Jay

2018-03-19

A wide bandwidth, ultra-thin, metasurface is reported that facilitates wide angle beam scanning. Each unit cell of the metasurface contains a multi-resonant, strongly-coupled unequal arm Jerusalem cross element. This element consists of two bent-arm, orthogonal, capacitively loaded strips. The wide bandwidth of the metasurface is achieved by taking advantage of the strong coupling within and between its multi-resonant elements. A prototype of the proposed metasurface has been fabricated and measured. The design concept has been validated by the measured results. The proposed metasurface is able to alleviate the well-known problem of impedance mismatch caused by mutual coupling when the main beam of an array is scanned. In order to validate the wideband and wide scanning ability of the proposed metasurface, it is integrated with a wideband antenna array as a wide angle impedance matching element. The metasurface-array combination facilitates wide angle scanning over a 6:1 impedance bandwidth without the need for bulky dielectrics or multi-layered structures.

Radiographic comparison of surgical hip dislocation and hip arthroscopy for treatment of cam deformity in femoroacetabular impingement.

PubMed

Bedi, Asheesh; Zaltz, Ira; De La Torre, Katrina; Kelly, Bryan T

2011-07-01

Whether open or arthroscopic techniques are employed, the goal of femoroacetabular impingement (FAI) surgery is to achieve impingement-free range of motion. While arthroscopic approaches have improved and gained popularity, an objective evaluation of the surgical correction achieved with this approach compared with open surgery remains to be defined in the literature. This study was undertaken to compare the efficacy of arthroscopic osteoplasty and open surgical dislocation in treating FAI dysmorphology in a consecutive series of patients. Cohort study; Level of evidence, 3. Surgical treatment was performed in 60 male patients under 40 years of age for symptomatic FAI refractory to nonoperative management. Patients were matched (not randomized) to treatment groups: 30 patients (15 left and 15 right hips) underwent arthroscopic cam and/or rim osteoplasty with labral debridement and/or refixation by an arthroscopic surgeon; and 30 (14 left and 16 right hips) underwent open surgical dislocation, cam and/or rim osteoplasty, and labral debridement or refixation by a hip preservation surgeon. Anteroposterior (AP) pelvis and extended-neck (Dunn) lateral radiographs were obtained and the depth of resection and arc of resection were measured by assessment of anterior femoral head-neck offset, AP and lateral α angle, and β angle on preoperative and postoperative radiographs. In the arthroscopic group, the extended-neck lateral α angle was reduced by a mean of 17.2° (28.3%, P < .05), AP α angle was reduced by a mean of 12.6° (16.8%), anterior head-neck offset improved 5.0 mm (111%, P < .05), and β angle increased by a mean of 23.1°. In the open dislocation group, the extended-neck lateral α angle was reduced by a mean of 21.2° (30.7%, P < .05), AP α angle was reduced by a mean of 20.1° (25.7%), anterior head-neck offset improved 6.56 mm (108%, P < .05), and β angle increased by a mean of 18.35°. Arthroscopic osteoplasty can restore head-neck offset and achieve similar depth, arc, and proximal-distal resection with comparable efficacy to open surgical dislocation for anterior and anterosuperior cam and focal rim impingement deformity. The open technique, however, may allow greater correction of posterosuperior loss of femoral offset and may be favorable for FAI patterns that demonstrate considerable proximal femoral deformity on AP radiographs.

The effect of subject measurement error on joint kinematics in the conventional gait model: Insights from the open-source pyCGM tool using high performance computing methods.

PubMed

Schwartz, Mathew; Dixon, Philippe C

2018-01-01

The conventional gait model (CGM) is a widely used biomechanical model which has been validated over many years. The CGM relies on retro-reflective markers placed along anatomical landmarks, a static calibration pose, and subject measurements as inputs for joint angle calculations. While past literature has shown the possible errors caused by improper marker placement, studies on the effects of inaccurate subject measurements are lacking. Moreover, as many laboratories rely on the commercial version of the CGM, released as the Plug-in Gait (Vicon Motion Systems Ltd, Oxford, UK), integrating improvements into the CGM code is not easily accomplished. This paper introduces a Python implementation for the CGM, referred to as pyCGM, which is an open-source, easily modifiable, cross platform, and high performance computational implementation. The aims of pyCGM are to (1) reproduce joint kinematic outputs from the Vicon CGM and (2) be implemented in a parallel approach to allow integration on a high performance computer. The aims of this paper are to (1) demonstrate that pyCGM can systematically and efficiently examine the effect of subject measurements on joint angles and (2) be updated to include new calculation methods suggested in the literature. The results show that the calculated joint angles from pyCGM agree with Vicon CGM outputs, with a maximum lower body joint angle difference of less than 10-5 degrees. Through the hierarchical system, the ankle joint is the most vulnerable to subject measurement error. Leg length has the greatest effect on all joints as a percentage of measurement error. When compared to the errors previously found through inter-laboratory measurements, the impact of subject measurements is minimal, and researchers should rather focus on marker placement. Finally, we showed that code modifications can be performed to include improved hip, knee, and ankle joint centre estimations suggested in the existing literature. The pyCGM code is provided in open source format and available at https://github.com/cadop/pyCGM.

The effect of subject measurement error on joint kinematics in the conventional gait model: Insights from the open-source pyCGM tool using high performance computing methods

PubMed Central

Dixon, Philippe C.

2018-01-01

The conventional gait model (CGM) is a widely used biomechanical model which has been validated over many years. The CGM relies on retro-reflective markers placed along anatomical landmarks, a static calibration pose, and subject measurements as inputs for joint angle calculations. While past literature has shown the possible errors caused by improper marker placement, studies on the effects of inaccurate subject measurements are lacking. Moreover, as many laboratories rely on the commercial version of the CGM, released as the Plug-in Gait (Vicon Motion Systems Ltd, Oxford, UK), integrating improvements into the CGM code is not easily accomplished. This paper introduces a Python implementation for the CGM, referred to as pyCGM, which is an open-source, easily modifiable, cross platform, and high performance computational implementation. The aims of pyCGM are to (1) reproduce joint kinematic outputs from the Vicon CGM and (2) be implemented in a parallel approach to allow integration on a high performance computer. The aims of this paper are to (1) demonstrate that pyCGM can systematically and efficiently examine the effect of subject measurements on joint angles and (2) be updated to include new calculation methods suggested in the literature. The results show that the calculated joint angles from pyCGM agree with Vicon CGM outputs, with a maximum lower body joint angle difference of less than 10-5 degrees. Through the hierarchical system, the ankle joint is the most vulnerable to subject measurement error. Leg length has the greatest effect on all joints as a percentage of measurement error. When compared to the errors previously found through inter-laboratory measurements, the impact of subject measurements is minimal, and researchers should rather focus on marker placement. Finally, we showed that code modifications can be performed to include improved hip, knee, and ankle joint centre estimations suggested in the existing literature. The pyCGM code is provided in open source format and available at https://github.com/cadop/pyCGM. PMID:29293565

Grooves and Kinks in the Rings

NASA Image and Video Library

2017-06-19

Many of the features seen in Saturn's rings are shaped by the planet's moons. This view from NASA's Cassini spacecraft shows two different effects of moons that cause waves in the A ring and kinks in a faint ringlet. The view captures the outer edge of the 200-mile-wide (320-kilometer-wide) Encke Gap, in the outer portion of Saturn's A ring. This is the same region features the large propeller called Earhart. Also visible here is one of several kinked and clumpy ringlets found within the gap. Kinks and clumps in the Encke ringlet move about, and even appear and disappear, in part due to the gravitational effects of Pan -- which orbits in the gap and whose gravitational influence holds it open. The A ring, which takes up most of the image on the left side, displays wave features caused by Pan, as well as the moons Pandora and Prometheus, which orbit a bit farther from Saturn on both sides of the planet's F ring. This view was taken in visible light with the Cassini spacecraft narrow-angle camera on March 22, 2017, and looks toward the sunlit side of the rings from about 22 degrees above the ring plane. The view was acquired at a distance of approximately 63,000 miles (101,000 kilometers) from Saturn and at a phase angle (the angle between the sun, the rings and the spacecraft) of 59 degrees. Image scale is 1,979 feet (603 meters) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21333

Correlations between Preoperative Angle Parameters and Postoperative Unpredicted Refractive Errors after Cataract Surgery in Open Angle Glaucoma (AOD 500).

PubMed

Lee, Wonseok; Bae, Hyoung Won; Lee, Si Hyung; Kim, Chan Yun; Seong, Gong Je

2017-03-01

To assess the accuracy of intraocular lens (IOL) power prediction for cataract surgery with open angle glaucoma (OAG) and to identify preoperative angle parameters correlated with postoperative unpredicted refractive errors. This study comprised 45 eyes from 45 OAG subjects and 63 eyes from 63 non-glaucomatous cataract subjects (controls). We investigated differences in preoperative predicted refractive errors and postoperative refractive errors for each group. Preoperative predicted refractive errors were obtained by biometry (IOL-master) and compared to postoperative refractive errors measured by auto-refractometer 2 months postoperatively. Anterior angle parameters were determined using swept source optical coherence tomography. We investigated correlations between preoperative angle parameters [angle open distance (AOD); trabecular iris surface area (TISA); angle recess area (ARA); trabecular iris angle (TIA)] and postoperative unpredicted refractive errors. In patients with OAG, significant differences were noted between preoperative predicted and postoperative real refractive errors, with more myopia than predicted. No significant differences were recorded in controls. Angle parameters (AOD, ARA, TISA, and TIA) at the superior and inferior quadrant were significantly correlated with differences between predicted and postoperative refractive errors in OAG patients (-0.321 to -0.408, p<0.05). Superior quadrant AOD 500 was significantly correlated with postoperative refractive differences in multivariate linear regression analysis (β=-2.925, R²=0.404). Clinically unpredicted refractive errors after cataract surgery were more common in OAG than in controls. Certain preoperative angle parameters, especially AOD 500 at the superior quadrant, were significantly correlated with these unpredicted errors.

Correlations between Preoperative Angle Parameters and Postoperative Unpredicted Refractive Errors after Cataract Surgery in Open Angle Glaucoma (AOD 500)

PubMed Central

Lee, Wonseok; Bae, Hyoung Won; Lee, Si Hyung; Kim, Chan Yun

2017-01-01

Purpose To assess the accuracy of intraocular lens (IOL) power prediction for cataract surgery with open angle glaucoma (OAG) and to identify preoperative angle parameters correlated with postoperative unpredicted refractive errors. Materials and Methods This study comprised 45 eyes from 45 OAG subjects and 63 eyes from 63 non-glaucomatous cataract subjects (controls). We investigated differences in preoperative predicted refractive errors and postoperative refractive errors for each group. Preoperative predicted refractive errors were obtained by biometry (IOL-master) and compared to postoperative refractive errors measured by auto-refractometer 2 months postoperatively. Anterior angle parameters were determined using swept source optical coherence tomography. We investigated correlations between preoperative angle parameters [angle open distance (AOD); trabecular iris surface area (TISA); angle recess area (ARA); trabecular iris angle (TIA)] and postoperative unpredicted refractive errors. Results In patients with OAG, significant differences were noted between preoperative predicted and postoperative real refractive errors, with more myopia than predicted. No significant differences were recorded in controls. Angle parameters (AOD, ARA, TISA, and TIA) at the superior and inferior quadrant were significantly correlated with differences between predicted and postoperative refractive errors in OAG patients (-0.321 to -0.408, p<0.05). Superior quadrant AOD 500 was significantly correlated with postoperative refractive differences in multivariate linear regression analysis (β=-2.925, R2=0.404). Conclusion Clinically unpredicted refractive errors after cataract surgery were more common in OAG than in controls. Certain preoperative angle parameters, especially AOD 500 at the superior quadrant, were significantly correlated with these unpredicted errors. PMID:28120576

Experimental study of the possibility of reducing the resistance and unevenness of output field of velocities in flat diffuser channels with large opening angles

NASA Astrophysics Data System (ADS)

Dmitriev, S. S.; Vasil'ev, K. E.; Mokhamed, S. M. S. O.; Gusev, A. A.; Barbashin, A. V.

2017-11-01

In modern combined cycle gas turbines (CCGT), when designing the reducers from the output diffuser of a gas turbine to a boiler-utilizer, wide-angle diffusers are used, in which practically from the input a flow separation and transition to jet stream regime occurs. In such channels, the energy loss in the field of velocities sharply rise and the field of velocities in the output from them is characterized by considerable unevenness that worsens the heat transfer process in the first by motion tube bundles of the boiler-utilizer. The results of experimental research of the method for reducing the energy loss and alignment of the field of velocities at the output from a flat asymmetrical diffuser channel with one deflecting wall with the opening angle of 40° by means of placing inside the channel the flat plate parallel to the deflecting wall are presented in the paper. It is revealed that, at this placement of the plate in the channel, it has a chance to reduce the energy loss by 20%, considerably align the output field of velocities, and decrease the dynamic loads on the walls in the output cross-section. The studied method of resistance reduction and alignment of the fields of velocities in the flat diffuser channels was used for optimization of the reducer from the output diffuser of the gas turbine to the boiler-utilizer of CCGT of PGU-450T type of Kaliningrad Thermal Power Plant-2. The obtained results are evidence that the configuration of the reducer installed in the PGU-450T of Kaliningrad Thermal Power Plant-2 is not optimal. It follows also from the obtained data that working-off the reducer should be necessarily conducted by the test results of the channel consisting of the model of reducer with the model of boiler-utilizer installed behind it. Application of the method of alignment of output field of velocities and reducing the resistance in the wide-angle diffusers investigated in the work made it possible—when using the known model of diffusion reducer for PGU-450T, which is bad from the standpoint of aerodynamics— to reduce the value of the coefficient of the total loss by almost 20% as compared with the model of real reducer of PGU-450T.

Origin of the wide-angle hot H2 in DG Tauri. New insight from SINFONI spectro-imaging

NASA Astrophysics Data System (ADS)

Agra-Amboage, V.; Cabrit, S.; Dougados, C.; Kristensen, L. E.; Ibgui, L.; Reunanen, J.

2014-04-01

Context. The origin of protostellar jets remains a major open question in star formation. Magnetohydrodynamical (MHD) disc winds are an important mechanism to consider, because they would have a significant impact on planet formation and migration. Aims: We wish to test the origins proposed for the extended hot H2 at 2000 K around the atomic jet from the T Tauri star DG Tau, in order to constrain the wide-angle wind structure and the possible presence of an MHD disc wind in this prototypical source. Methods: We present spectro-imaging observations of the DG Tau jet in H2 1-0 S(1) with 0.̋ 12 angular resolution, obtained with SINFONI/VLT. Thanks to spatial deconvolution by the point spread function and to careful correction for wavelength calibration and for uneven slit illumination (to within a few km s-1), we performed a thorough analysis and modeled the morphology and kinematics. We also compared our results with studies in [Fe II], [O I], and FUV-pumped H2. Absolute flux calibration yields the H2 column/volume density and emission surface, and narrows down possible shock conditions. Results: The limb-brightened H2 1-0 S(1) emission in the blue lobe is strikingly similar to FUV-pumped H2 imaged 6 yr later, confirming that they trace the same hot gas and setting an upper limit <12 km s-1 on any expansion proper motion. The wide-angle rims are at lower blueshifts (between -5 and 0 km s-1) than probed by narrow long-slit spectra. We confirm that they extend to larger angle and to lower speed the onion-like velocity structure observed in optical atomic lines. The latter is shown to be steady over ≥4 yr but undetected in [Fe II] by SINFONI, probably due to strong iron depletion. The rim thickness ≤14 AU rules out excitation by C-type shocks, and J-type shock speeds are constrained to ≃10 km s-1. Conclusions: We find that explaining the H2 1-0 S(1) wide-angle emission with a shocked layer requires either a recent outburst (15 yr) into a pre-existing ambient outflow or an excessive wind mass flux. A slow photoevaporative wind from the dense irradiated disc surface and an MHD disc wind heated by ambipolar diffusion seem to be more promising and need to be modeled in more detail. Better observational constraints on proper motion and rim thickness would also be crucial for clarifying the origin of this structure.

Stable high absorption metamaterial for wide-angle incidence of terahertz wave

NASA Astrophysics Data System (ADS)

Du, Qiujiao; Zeng, Zuoxun; Xiang, Dong; Lv, Tao; Zhang, Guangyong; Yang, Hongwu

2014-04-01

We propose a metamaterial based on metallic Jerusalem cross and cross-wire structures for realizing relatively stable high absorption with respect to the wide angle incidence of both polarized terahertz (THz) waves. Numerical simulations are carried out to verify the proposed absorber. For both transverse electric and transverse magnetic polarizations, absorptions around 0.93 THz reach nearly up to unity under normal incidence and maintain above 97% over a wide incidence angle range. The THz absorber can be easily micro-fabricated due to a thickness about 40 times smaller than operating wavelength. The proposed metamaterial is a promising candidate as absorbing element in THz thermal imager, due to its wide angle, stable high absorption and very thin thickness.

Wide-angle full-vector beam propagation method based on an alternating direction implicit preconditioner

NASA Astrophysics Data System (ADS)

Chui, Siu Lit; Lu, Ya Yan

2004-03-01

Wide-angle full-vector beam propagation methods (BPMs) for three-dimensional wave-guiding structures can be derived on the basis of rational approximants of a square root operator or its exponential (i.e., the one-way propagator). While the less accurate BPM based on the slowly varying envelope approximation can be efficiently solved by the alternating direction implicit (ADI) method, the wide-angle variants involve linear systems that are more difficult to handle. We present an efficient solver for these linear systems that is based on a Krylov subspace method with an ADI preconditioner. The resulting wide-angle full-vector BPM is used to simulate the propagation of wave fields in a Y branch and a taper.

Wide-angle full-vector beam propagation method based on an alternating direction implicit preconditioner.

PubMed

Chui, Siu Lit; Lu, Ya Yan

2004-03-01

Wide-angle full-vector beam propagation methods (BPMs) for three-dimensional wave-guiding structures can be derived on the basis of rational approximants of a square root operator or its exponential (i.e., the one-way propagator). While the less accurate BPM based on the slowly varying envelope approximation can be efficiently solved by the alternating direction implicit (ADI) method, the wide-angle variants involve linear systems that are more difficult to handle. We present an efficient solver for these linear systems that is based on a Krylov subspace method with an ADI preconditioner. The resulting wide-angle full-vector BPM is used to simulate the propagation of wave fields in a Y branch and a taper.

Some Characteristics of Fuel Sprays from Open Nozzles

NASA Technical Reports Server (NTRS)

Rothrock, A M; Lee, D W

1930-01-01

The penetration and cone-angle of fuel sprays from open nozzles were recorded with the NACA Spray Photography Equipment. The results show that for injection systems in which the rate of pressure rise at the discharge orifice is high, open nozzles give spray-tip velocities and penetrations which compare favorably with those of closed nozzles. The spray cone-angle was the same for all tests, although open nozzles having different orifice diameters were used, and one nozzle was used both as an open and as a closed nozzle. In designing a fuel system using open nozzles, particular care must be taken to avoid air pockets. The check valve should be placed close to the discharge orifice.

[Fe II] emissions associated with the young interacting binary UY Aurigae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pyo, Tae-Soo; Hayashi, Masahiko; Beck, Tracy L.

We present high-resolution 1.06-1.28 μm spectra toward the interacting binary UY Aur obtained with GEMINI/NIFS and the adaptive optics system Altair. We have detected [Fe II] λ1.257 μm and He I λ1.083 μm lines from both UY Aur A (the primary source) and UY Aur B (the secondary). In [Fe II] UY Aur A drives fast and widely opening outflows with an opening angle of ∼90° along a position angle of ∼40°, while UY Aur B is associated with a redshifted knot. The blueshifted and redshifted emissions show a complicated structure between the primary and secondary. The radial velocities ofmore » the [Fe II] emission features are similar for UY Aur A and B: ∼ –100 km s{sup –1} for the blueshifted emission and ∼ +130 km s{sup –1} for the redshifted component. The He I line profile observed toward UY Aur A comprises a central emission feature with deep absorptions at both blueshifted and redshifted velocities. These absorption features may be explained by stellar wind models. The He I line profile of UY Aur B shows only an emission feature.« less

Linkage to 10q22 for maximum intraocular pressure and 1p32 for maximum cup-to-disc ratio in an extended primary open-angle glaucoma pedigree.

PubMed

Charlesworth, Jac C; Dyer, Thomas D; Stankovich, Jim M; Blangero, John; Mackey, David A; Craig, Jamie E; Green, Catherine M; Foote, Simon J; Baird, Paul N; Sale, Michèle M

2005-10-01

The purpose of this study was to identify genetic contributions to primary open-angle glaucoma (POAG) through investigations of two quantitative components of the POAG phenotype. Genome-wide multipoint variance-components linkage analyses of maximum recorded intraocular pressure (IOP) and maximum vertical cup-to-disc ratio were conducted on data from a single, large Australian POAG pedigree that has been found to segregate the myocilin Q368X mutation in some individuals. Multipoint linkage analysis of maximum recorded IOP produced a peak LOD score of 3.3 (P = 0.00015) near marker D10S537 on 10q22, whereas the maximum cup-to-disc ratio produced a peak LOD score of 2.3 (P = 0.00056) near markers D1S197 to D1S220 on 1p32. Inclusion of the myocilin Q368X mutation as a covariate provided evidence of an interaction between this mutation and the IOP and cup-to-disc ratio loci. Significant linkage has been identified for maximum IOP and suggestive linkage for vertical cup-to-disc ratio. Identification of genes contributing to the variance of these traits will enhance understanding of the pathophysiology of POAG as a whole.

Myocardial infarction increases progressive visual field defects in well treated early primary open angle glaucoma--a prospective case control study.

PubMed

Mondal, Lakshmikanta; Baidya, Krishnapada; Choudhury, Himadri; Roy, Rupam

2013-06-01

The purpose of the study was to evaluate the progression of glaucomatous field damage in patients with stable primary open angle glaucoma after an attack of myocardial infarction. In this case control study, 62 open angle glaucoma patients were selected and regularly followed up. Among 62 patients, 9 had an attack of myocardial infarction. The intra-ocular pressure and visual field progression of both the groups (myocardial infarction versus no myocardial infarction) were analysed. Three (33.3%) out of 9 patients who had suffered from myocardial infarction showed progressive visual field loss whereas only 9 (16.9%) out of 53 patients who did not suffer from myocardial infarction, showed progressive field changes. Both the groups had stable target intra-ocular pressure between 14 and 16 mm Hg. Myocardial infarction may adversely influence the progression of primary open angle glaucoma which is suspected to result from ischaemia induced neuronal loss and only control of intraocular pressure is not the only solution. We have to look for other drugs that prevents ischaemia induced neuronal damage.

MOJAVE - XIV. Shapes and opening angles of AGN jets

NASA Astrophysics Data System (ADS)

Pushkarev, A. B.; Kovalev, Y. Y.; Lister, M. L.; Savolainen, T.

2017-07-01

We present 15 GHz stacked VLBA images of 373 jets associated with active galactic nuclei (AGNs) having at least five observing epochs within a 20 yr time interval 1994-2015 from the Monitoring Of Jets in Active galactic nuclei with VLBA Experiments (MOJAVE) programme and/or its precursor, the 2-cm VLBA Survey. These data are supplemented by 1.4 GHz single-epoch VLBA observations of 135 MOJAVE AGNs to probe larger scale jet structures. The typical jet geometry is found to be close to conical on scales from hundreds to thousands of parsecs, while a number of galaxies show quasi-parabolic streamlines on smaller scales. A true jet geometry in a considerable fraction of AGNs appears only after stacking epochs over several years. The jets with significant radial accelerated motion undergo more active collimation. We have analysed total intensity jet profiles transverse to the local jet ridgeline and derived both apparent and intrinsic opening angles of the flows, with medians of 21.5° and 1.3°, respectively. The Fermi LAT-detected gamma-ray AGNs in our sample have, on average, wider apparent and narrower intrinsic opening angle, and smaller viewing angle than non-LAT-detected AGNs. We have established a highly significant correlation between the apparent opening angle and gamma-ray luminosity, driven by Doppler beaming and projection effects.

Gravity field error analysis for pendulum formations by a semi-analytical approach

NASA Astrophysics Data System (ADS)

Li, Huishu; Reubelt, Tilo; Antoni, Markus; Sneeuw, Nico

2017-03-01

Many geoscience disciplines push for ever higher requirements on accuracy, homogeneity and time- and space-resolution of the Earth's gravity field. Apart from better instruments or new observables, alternative satellite formations could improve the signal and error structure compared to Grace. One possibility to increase the sensitivity and isotropy by adding cross-track information is a pair of satellites flying in a pendulum formation. This formation contains two satellites which have different ascending nodes and arguments of latitude, but have the same orbital height and inclination. In this study, the semi-analytical approach for efficient pre-mission error assessment is presented, and the transfer coefficients of range, range-rate and range-acceleration gravitational perturbations are derived analytically for the pendulum formation considering a set of opening angles. The new challenge is the time variations of the opening angle and the range, leading to temporally variable transfer coefficients. This is solved by Fourier expansion of the sine/cosine of the opening angle and the central angle. The transfer coefficients are further applied to assess the error patterns which are caused by different orbital parameters. The simulation results indicate that a significant improvement in accuracy and isotropy is obtained for small and medium initial opening angles of single polar pendulums, compared to Grace. The optimal initial opening angles are 45° and 15° for accuracy and isotropy, respectively. For a Bender configuration, which is constituted by a polar Grace and an inclined pendulum in this paper, the behaviour of results is dependent on the inclination (prograde vs. retrograde) and on the relative baseline orientation (left or right leading). The simulation for a sun-synchronous orbit shows better results for the left leading case.

Flow field and performance characteristics of combustor diffusers: A basic study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hestermann, R.; Kim, S.; Ben Khaled, A.

1995-10-01

Results of a detailed study concerning the influence of geometric as well as fluid mechanic parameters o the performance of a plane model combustor diffuser in cold flow are presented. For a qualitative insight into the complex flow field inside the prediffuser, the sudden expansion region, and the flow field around the flame tube dome, results of a flow visualization study with the hydrogen bubble method as well as with the ink jet method are presented for different opening angles of the prediffuser and for different flame tube distances. Also, quantitative data from detailed measurements with LDV and conventional pressuremore » probes in a geometrically similar air-driven setup are presented. These data clearly demonstrate the effect of boundary layer thickness as well as the influence of different turbulence levels at the entry of the prediffuser on the performance characteristics of combustor diffusers. The possibility of getting an unseparated flow field inside the prediffuser even at large opening angles by appropriately matching the diffuser`s opening angle and the flame tube distance is demonstrated. Also, for flows with an increased turbulence level at the entrance--all other conditions held constant--an increased opening angle can be realized without experiencing flow separation. The comparison of the experimental data with predictions utilizing a finite-volume-code based on a body-fitted coordinate system for diffusers with an included total opening angle less than 18 deg demonstrates the capability of describing the flow field in combustor diffusers with reasonable accuracy.« less

An all-reflective wide-angle flat-field telescope for space

NASA Technical Reports Server (NTRS)

Hallam, K. L.; Howell, B. J.; Wilson, M. E.

1984-01-01

An all-reflective wide-angle flat-field telescope (WAFFT) designed and built at Goddard Space Flight Center demonstrates the markedly improved wide-angle imaging capability which can be achieved with a design based on a recently announced class of unobscured 3-mirror optical systems. Astronomy and earth observation missions in space dictate the necessity or preference for wide-angle all-reflective systems which can provide UV through IR wavelength coverage and tolerate the space environment. An initial prototype unit has been designed to meet imaging requirements suitable for monitoring the ultraviolet sky from space. The unobscured f/4, 36 mm efl system achieves a full 20 x 30 deg field of view with resolution over a flat focal surface that is well matched for use with advanced ultraviolet image array detectors. Aspects of the design and fabrication approach, which have especially important bearing on the system solution, are reviewed; and test results are compared with the analytic performance predictions. Other possible applications of the WAFFT class of imaging system are briefly discussed. The exceptional wide-angle, high quality resolution, and very wide spectral coverage of the WAFFT-type optical system could make it a very important tool for future space research.

Short-focus and ultra-wide-angle lens design in wavefront coding

NASA Astrophysics Data System (ADS)

Zhang, Jiyan; Huang, Yuanqing; Xiong, Feibing

2016-10-01

Wavefront coding (WFC) is a hybrid technology designed to increase depth of field of conventional optics. The goal of our research is to apply this technology to the short-focus and ultra-wide-angle lens which suffers from the aberration related with large field of view (FOV) such as coma and astigmatism. WFC can also be used to compensate for other aberration which is sensitive to the FOV. Ultra-wide-angle lens has a little depth of focus because it has small F number and short-focus. We design a hybrid lens combing WFC with the ultra-wide-angle lens. The full FOV and relative aperture of the final design are up to170° and 1/1.8 respectively. The focal length is 2 mm. We adopt the cubic phase mask (CPM) in the design. The conventional design will have a wide variation of the point spread function (PSF) across the FOV and it is very sensitive with the variation of the FOV. The new design we obtain the PSF is nearly invariant over the whole FOV. But the result of the design also shows the little difference between the horizontal and vertical length of the PSF. We analyze that the CPM is non-symmetric phase mask and the FOV is so large, which will generate variation in the final image quality. For that reason, we apply a new method to avoid that happened. We try to make the rays incident on the CPM with small angle and decrease the deformation of the PSF. The experimental result shows the new method to optimize the CPM is fit for the ultra-wide-angle lens. The research above will be a helpful instruction to design the ultra-wide-angle lens with WFC.

Hong's grading for evaluating anterior chamber angle width.

PubMed

Kim, Seok Hwan; Kang, Ja Heon; Park, Ki Ho; Hong, Chul

2012-11-01

To compare Hong's grading method with anterior segment optical coherence tomography (AS-OCT), gonioscopy, and the dark-room prone-position test (DRPT) for evaluating anterior chamber width. The anterior chamber angle was graded using Hong's grading method, and Hong's angle width was calculated from the arctangent of Hong's grades. The correlation between Hong's angle width and AS-OCT parameters was analyzed. The area under the receiver operating characteristic curve (AUC) for Hong's grading method when discriminating between narrow and open angles as determined by gonioscopy was calculated. Correlation analysis was performed between Hong's angle width and intraocular pressure (IOP) changes determined by DRPT. A total of 60 subjects were enrolled. Of these subjects, 53.5 % had a narrow angle. Hong's angle width correlated significantly with the AS-OCT parameters (r = 0.562-0.719, P < 0.01). A Bland-Altman plot showed relatively good agreement between Hong's angle width and the angle width obtained by AS-OCT. The ability of Hong's grading method to discriminate between open and narrow angles was good (AUC = 0.868, 95 % CI 0.756-0.942). A significant linear correlation was found between Hong's angle width and IOP change determined by DRPT (r = -0.761, P < 0.01). Hong's grading method is useful for detecting narrow angles. Hong's grading correlated well with AS-OCT parameters and DRPT.

Crustal structure of the Ionian basin and eastern Sicily margin : results from a wide angle seismic survey and implication for the crustal nature and origin of the basin, and the recent tear fault location

NASA Astrophysics Data System (ADS)

Gutscher, M. A.; Dellong, D.; Klingelhoefer, F.; Kopp, H.; Graindorge, D.; Margheriti, L.; Moretti, M.

2017-12-01

In the Ionian Sea (Central Mediterranean) the slow convergence between Africa and Eurasia results in the formation of a narrow subduction zone. The nature of the crust and lithosphere of the subducting plate remain debated and could represent the last remnants of the Neo-Tethys ocean. The rifting mechanism that produced the Ionian basin are also still under discussion with the Malta escarpment representing a possible remnant of this opening. At present, this subduction is still retreating to the south-east (motion occurring since the last 35 Ma) but is confined to the narrow Ionian Basin. In order to accommodate slab roll-back, a major lateral slab tear fault is required. This fault is thought to propagate along the eastern Sicily margin but its precise location remains controversial. This study focuses on the deep crustal structure of the Eastern-Sicily margin and the Malta Escarpment by presenting two wide-angle velocity profiles crossing these structures roughly orthogonally. The data used for the forward velocity modeling were acquired onboard the R/V Meteor during the DIONYSUS cruise in 2014. The results image an oceanic crust within the Ionian basin as well as the deep structure of the Malta Escarpment which presents characteristics of a transform margin. A deep and asymmetrical sedimentary basin is imaged south of the Messina strait and seems to have opened in between the Calabrian and Peloritan continental terranes. The interpretation of the velocity models suggests that the tear fault is located east of the Malta Escarpment, along the Alfeo fault system.

Risk factors for predicting visual field progression in Chinese patients with primary open-angle glaucoma: A retrospective study.

PubMed

Hung, Kuo-Hsuan; Cheng, Ching-Yu; Liu, Catherine Jui-Ling

2015-07-01

Glaucoma is a leading cause of irreversible blindness worldwide. It is characterized by progressive deterioration of the visual field (VF) that results in a complete loss of vision. This study aimed to determine the risk factors associated with VF progression in Chinese patients with primary open-angle glaucoma (POAG). We reviewed the charts of POAG patients who visited our clinic between July 2009 and June 2010. We included patients with five or more reliable VF tests using the Humphrey Field Analyzer (Humphrey Instruments, San Leandro, CA, USA) during a period of at least 2 years. The scoring system of the Collaborative Initial Glaucoma Treatment Study (CIGTS) was used to code the VF. Progression was defined as an increasing score ≥3, compared to the averaged baseline data. Univariate and multivariate logistic regression analyses were performed to identify the risk factors of VF progression. There were 92 patients (representing 92 eyes) with an average of 8.9 reliable VFs over a mean follow up of 5.4 years. Multivariate logistic regression showed that eyes with more VF tests [odds ratio (OR) = 1.500, p < 0.010] and either increased peak intraocular pressure (IOP) (OR = 1.235, p = 0.044) or a wide IOP range (OR = 1.165, p = 0.041) favored VF progression. High myopia (less than -6.0 D) was not a risk factor (OR = 1.289, p = 0.698) for VF progression in this study. In addition to a greater number of VF tests, Chinese patients with treated POAG who experienced a high peak IOP or a wide range of IOP during follow up were more likely to have VF deterioration. Copyright © 2015. Published by Elsevier Taiwan.

Mechanical strength assessment of a drilled hole in the contralateral cortex at the end of the open wedge for high tibial osteotomy.

PubMed

Diffo Kaze, Arnaud; Maas, Stefan; Hoffmann, Alexander; Pape, Dietrich

2017-12-01

This study aimed to investigate, by means of finite element analysis, the effect of a drill hole at the end of a horizontal osteotomy to reduce the risk of lateral cortex fracture while performing an opening wedge high tibial osteotomy (OWHTO). The question was whether drilling a hole relieves stress and increases the maximum correction angle without fracture of the lateral cortex depending on the ductility of the cortical bone. Two different types of osteotomy cuts were considered; one with a drill hole (diameter 5 mm) and the other without the hole. The drill holes were located about 20 mm distally to the tibial plateau and 6 mm medially to the lateral cortex, such that the minimal thickness of the contralateral cortical bone was 5 mm. Based on finite element calculations, two approaches were used to compare the two types of osteotomy cuts considered: (1) Assessing the static strength using local stresses following the idea of the FKM-guideline, subsequently referred to as the "FKM approach" and (2) limiting the total strain during the opening of the osteotomy wedge, subsequently referred to as "strain approach". A critical opening angle leading to crack initiation in the opposite lateral cortex was determined for each approach and was defined as comparative parameter. The relation to bone aging was investigated by considering the material parameters of cortical bones from young and old subjects. The maximum equivalent (von-Mises) stress was smaller for the cases with a drill hole at the end of the osteotomy cut. The critical angle was approximately 1.5 times higher for the specimens with a drill hole compared to those without. This corresponds to an average increase of 50%. The calculated critical angle for all approaches is below 5°. The critical angle depends on the used approach, on patient's age and assumed ductility of the cortical bone. Drilling a hole at the end of the osteotomy reduces the stresses in the lateral cortex and increases the critical opening angle prior to cracking of the opposite cortex in specimen with small correction angles. But the difference from having a drill hole or not is not so significant, especially for older patients. The ductility of the cortical bone is the decisive parameter for the critical opening angle.

46 CFR 172.150 - Survival conditions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... waterline, in the final condition of sinkage, heel, and trim, must be below the lower edge of openings such.... (5) Side scuttles of the non-opening type. (b) Heel angle. (1) Except as described in paragraph (b)(2) of this section, the maximum angle of heel must not exceed 15 degrees (17 degrees if no part of the...

46 CFR 172.150 - Survival conditions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... waterline, in the final condition of sinkage, heel, and trim, must be below the lower edge of openings such.... (5) Side scuttles of the non-opening type. (b) Heel angle. (1) Except as described in paragraph (b)(2) of this section, the maximum angle of heel must not exceed 15 degrees (17 degrees if no part of the...

Ocular Biometrics of Myopic Eyes With Narrow Angles.

PubMed

Chong, Gabriel T; Wen, Joanne C; Su, Daniel Hsien-Wen; Stinnett, Sandra; Asrani, Sanjay

2016-02-01

The purpose of this study was to compare the ocular biometrics between myopic patients with and without narrow angles. Patients with a stable myopic refraction (myopia worse than -1.00 D spherical equivalent) were prospectively recruited. Angle status was assessed using gonioscopy and biometric measurements were performed using an anterior segment optical coherence tomography and an IOLMaster. A total of 29 patients (58 eyes) were enrolled with 13 patients (26 eyes) classified as having narrow angles and 16 patients (32 eyes) classified as having open angles. Baseline demographics of age, sex, and ethnicity did not differ significantly between the 2 groups. The patients with narrow angles were on average older than those with open angles but the difference did not reach statistical significance (P=0.12). The central anterior chamber depth was significantly less in the eyes with narrow angles (P=0.05). However, the average lens thickness, although greater in the eyes with narrow angles, did not reach statistical significance (P=0.10). Refractive error, axial lengths, and iris thicknesses did not differ significantly between the 2 groups (P=0.32, 0.47, 0.15). Narrow angles can occur in myopic eyes. Routine gonioscopy is therefore recommended for all patients regardless of refractive error.

Newly Designed Apparatus for Measuring the Angular Dependent Surface Emittance in a Wide Wavelength Range and at Elevated Temperatures up to 1400°C

NASA Astrophysics Data System (ADS)

Rydzek, M.; Stark, T.; Arduini-Schuster, M.; Manara, J.

2012-11-01

An optimized apparatus for measuring the angular dependent surface emittance up to elevated temperatures has been designed. This emittance measurement apparatus (EMMA) is coupled to a Bruker Vertex 70v FTIR-spectrometer, so that a wavelength range from about 2 μm up to 25 μm is accessible. The central part of the new apparatus is a double walled, stainless steel vessel which can be evacuated or filled with various gases or with air. Inside the vessel a cylindrical tube furnace is pivot-mounted on a system of discs, for automatically rotating up to an angle of 180°. This allows both, the measurement at different detection angles (0° to 85°) and a consecutive measurement of sample and black-body reference without ventilating and opening the pot. The aim of this work is to present the newly designed emittance measurement apparatus which enables the determination of the angular dependent spectral emittance of opaque samples at temperatures up to 1400 °C. Next to the setup of the apparatus, the measurement results of various materials are presented at different detection angles.

Extremely Soft X-Ray Flash as the Indicator of Off-axis Orphan GRB Afterglow

NASA Astrophysics Data System (ADS)

Urata, Yuji; Huang, Kuiyun; Yamazaki, Ryo; Sakamoto, Takanori

2015-06-01

We verified the off-axis jet model of X-ray flashes (XRFs) and examined a discovery of off-axis orphan gamma-ray burst (GRB) afterglows. The XRF sample was selected on the basis of the following three factors: (1) a constraint on the lower peak energy of the prompt spectrum {E}{obs}{src}, (2) redshift measurements, and (3) multicolor observations of an earlier (or brightening) phase. XRF 020903 was the only sample selected on the basis of these criteria. A complete optical multicolor afterglow light curve of XRF 020903 obtained from archived data and photometric results in the literature showed an achromatic brightening around 0.7 days. An off-axis jet model with a large observing angle (0.21 rad, which is twice the jet opening half-angle, {θ }{jet}) can naturally describe the achromatic brightening and the prompt X-ray spectral properties. This result indicates the existence of off-axis orphan GRB afterglow light curves. Events with a larger viewing angle (\\gt ∼ 2{θ }{jet}) could be discovered using an 8 m class telescope with wide-field imagers such as the Subaru Hyper-Suprime-Cam and the Large Synoptic Survey Telescope.

Wide-angle planar microtracking for quasi-static microcell concentrating photovoltaics

NASA Astrophysics Data System (ADS)

Price, Jared S.; Sheng, Xing; Meulblok, Bram M.; Rogers, John A.; Giebink, Noel C.

2015-02-01

Concentrating photovoltaics offer a way to lower the cost of solar power. However, the existing paradigm based on precise orientation of large-area concentrator modules towards the Sun limits their deployment to large, open land areas. Here, we explore an alternate approach using high-efficiency microcell photovoltaics embedded between a pair of plastic lenslet arrays to demonstrate quasi-static concentrating photovoltaic panels <1 cm thick that accomplish full-day tracking with >200x flux concentration ratio through small (<1 cm) lateral translation at fixed latitude tilt. Per unit of installed land area, cosine projection loss for fixed microtracking concentrating photovoltaic panels is ultimately offset by improved ground coverage relative to their conventional dual-axis counterparts, enabling a ~1.9x increase in daily energy output that may open up a new opportunity for compact, high-efficiency concentrating photovoltaics to be installed on rooftops and other limited-space urban environments.

Wide-angle planar microtracking for quasi-static microcell concentrating photovoltaics.

PubMed

Price, Jared S; Sheng, Xing; Meulblok, Bram M; Rogers, John A; Giebink, Noel C

2015-02-05

Concentrating photovoltaics offer a way to lower the cost of solar power. However, the existing paradigm based on precise orientation of large-area concentrator modules towards the Sun limits their deployment to large, open land areas. Here, we explore an alternate approach using high-efficiency microcell photovoltaics embedded between a pair of plastic lenslet arrays to demonstrate quasi-static concentrating photovoltaic panels <1 cm thick that accomplish full-day tracking with >200x flux concentration ratio through small (<1 cm) lateral translation at fixed latitude tilt. Per unit of installed land area, cosine projection loss for fixed microtracking concentrating photovoltaic panels is ultimately offset by improved ground coverage relative to their conventional dual-axis counterparts, enabling a ~1.9x increase in daily energy output that may open up a new opportunity for compact, high-efficiency concentrating photovoltaics to be installed on rooftops and other limited-space urban environments.

Wide-angle imaging system with fiberoptic components providing angle-dependent virtual material stops

NASA Technical Reports Server (NTRS)

Vaughan, Arthur H. (Inventor)

1993-01-01

A strip imaging wide angle optical system is provided. The optical system is provided with a 'virtual' material stop to avoid aberrational effects inherent in wide angle optical systems. The optical system includes a spherical mirror section for receiving light from a 180 deg strip or arc of a target image. Light received by the spherical mirror section is reflected to a frustoconical mirror section for subsequent rereflection to a row of optical fibers. Each optical fiber transmits a portion of the received light to a detector. The optical system exploits the narrow cone of acceptance associated with optical fibers to substantially eliminate vignetting effects inherent in wide angle systems. Further, the optical system exploits the narrow cone of acceptance of the optical fibers to substantially limit spherical aberration. The optical system is ideally suited for any application wherein a 180 deg strip image need be detected, and is particularly well adapted for use in hostile environments such as in planetary exploration.

Analysis of the EM scattering from arbitrary open-ended waveguide cavities using axial Gaussian Beam tracking

NASA Technical Reports Server (NTRS)

Burkholder, R. J.; Pathak, P. H.

1988-01-01

The electromagnetic (EM) scattering from a planar termination located inside relatively arbitrarily shaped open-ended waveguide cavities with smoothly curved interior walls is analyzed using a Gaussian Beam (GB) expansion of the incident plane wave fields in the open end. The cavities under consideration may contain perfectly-conducting interior walls with or without a thin layer of material coating, or the walls may be characterized by an impedance boundary condition. In the present approach, the GB's are tracked only to the termination of the waveguide cavity via beam reflections from interior waveguide cavity walls. The Gaussian beams are tracked approximately only along their beam axes; this approximation which remains valid for relatively well focussed beams assumes that an incident GB gives rise to a reflected GB with parameters related to the incident beam and the radius of curvature of the wall. It is found that this approximation breaks down for GB's which come close to grazing a convex surface and when the width of the incident beam is comparable to the radius of curvature of the surface. The expansion of the fields at the open end depend on the incidence angle only through the expansion coefficients, so the GB's need to be tracked through the waveguide cavity only once for a wide range of incidence angles. At the termination, the sum of all the GB's are integrated using a result developed from a generalized reciprocity principle, to give the fields scattered from the interior of the cavity. The rim edge at the open end of the cavity is assumed to be sharp and the external scattering from the rim is added separately using Geometrical Theory of Diffraction. The results based on the present approach are compared with solutions based on the hybrid asymptotic modal method. The agreement is found to be very good for cavities made up of planar surfaces, and also for cavities with curved surfaces which are not too long with respect to their width.

Performance Prediction of Darrieus-Type Hydroturbine with Inlet Nozzle Operated in Open Water Channels

NASA Astrophysics Data System (ADS)

Nakashima, K.; Watanabe, S.; Matsushita, D.; Tsuda, S.; Furukawa, A.

2016-11-01

Small hydropower is one of the renewable energies and is expected to be effectively used for local supply of electricity. We have developed Darrieus-type hydro-turbine systems, and among them, the Darrieus-turbine with a weir and a nozzle installed upstream of turbine is, so far, in success to obtain more output power by gathering all water into the turbine. However, there can several cases exist, in which installing the weir covering all the flow channel width is unrealistic, and in such cases, the turbine should be put alone in open channels without upstream weir. Since the output power is very small in such a utilization of small hydropower, it is important to derive more power for the cost reduction. In the present study, we parametrically investigate the preferable shape of the inlet nozzle for the Darrieus-type hydroturbine operated in an open flow channel. Experimental investigation is carried out in the open channel in our lab. Tested inlet nozzles are composed of two flat plates with the various nozzle converging angles and nozzle outlet (runner inlet) widths with the nozzle inlet width kept constant. As a result, the turbine with the nozzles having large converging angle and wide outlet width generates higher power. Two-dimensional unsteady numerical simulation is also carried out to qualitatively understand the flow mechanism leading to the better performance of turbine. Since the depth, the width and the flow rate in the real open flow channels are different from place to place and, in some cases from time to time, it is also important to predict the onsite performance of the hydroturbine from the lab experiment at planning stage. One-dimensional stream-tube model is developed for this purpose, in which the Darrieus-type hydroturbine with the inlet nozzle is considered as an actuator-disk modelled based on our experimental and numerical results.

Evaluation of the Quality of Action Cameras with Wide-Angle Lenses in Uav Photogrammetry

NASA Astrophysics Data System (ADS)

Hastedt, H.; Ekkel, T.; Luhmann, T.

2016-06-01

The application of light-weight cameras in UAV photogrammetry is required due to restrictions in payload. In general, consumer cameras with normal lens type are applied to a UAV system. The availability of action cameras, like the GoPro Hero4 Black, including a wide-angle lens (fish-eye lens) offers new perspectives in UAV projects. With these investigations, different calibration procedures for fish-eye lenses are evaluated in order to quantify their accuracy potential in UAV photogrammetry. Herewith the GoPro Hero4 is evaluated using different acquisition modes. It is investigated to which extent the standard calibration approaches in OpenCV or Agisoft PhotoScan/Lens can be applied to the evaluation processes in UAV photogrammetry. Therefore different calibration setups and processing procedures are assessed and discussed. Additionally a pre-correction of the initial distortion by GoPro Studio and its application to the photogrammetric purposes will be evaluated. An experimental setup with a set of control points and a prospective flight scenario is chosen to evaluate the processing results using Agisoft PhotoScan. Herewith it is analysed to which extent a pre-calibration and pre-correction of a GoPro Hero4 will reinforce the reliability and accuracy of a flight scenario.

Modeling the effect of preexisting joints on normal fault geometries using a brittle and cohesive material

NASA Astrophysics Data System (ADS)

Kettermann, M.; van Gent, H. W.; Urai, J. L.

2012-04-01

Brittle rocks, such as for example those hosting many carbonate or sandstone reservoirs, are often affected by different kinds of fractures that influence each other. Understanding the effects of these interactions on fault geometries and the formation of cavities and potential fluid pathways might be useful for reservoir quality prediction and production. Analogue modeling has proven to be a useful tool to study faulting processes, although usually the used materials do not provide cohesion and tensile strength, which are essential to create open fractures. Therefore, very fine-grained, cohesive, hemihydrate powder was used for our experiments. The mechanical properties of the material are scaling well for natural prototypes. Due to the fine grain size structures are preserved in in great detail. The used deformation box allows the formation of a half-graben and has initial dimensions of 30 cm width, 28 cm length and 20 cm height. The maximum dip-slip along the 60° dipping predefined basement fault is 4.5 cm and was fully used in all experiments. To setup open joints prior to faulting, sheets of paper placed vertically within the box to a depth of about 5 cm from top. The powder was then sieved into the box, embedding the paper almost entirely. Finally strings were used to remove the paper carefully, leaving open voids. Using this method allows the creation of cohesionless open joints while ensuring a minimum impact on the sensitive surrounding material. The presented series of experiments aims to investigate the effect of different angles between the strike of a rigid basement fault and a distinct joint set. All experiments were performed with a joint spacing of 2.5 cm and the fault-joint angles incrementally covered 0°, 4°, 8°, 12°, 16°, 20° and 25°. During the deformation time lapse photography from the top and side captured every structural change and provided data for post-processing analysis using particle imaging velocimetry (PIV). Additionally, stereo-photography at the final stage of deformation enabled the creation of 3D models to preserve basic geometric information. The models showed that at the surface the deformation localized always along preexisting joints, even when they strike at an angle to the basement-fault. In most cases faults intersect precisely at the maximum depth of the joints. With increasing fault-joint angle the deformation occurred distributed over several joints by forming stepovers with fractures oriented normal to the strike of the joints. No fractures were observed parallel to the basement fault. At low angles stepovers coincided with wedge-shaped structures between two joints that remain higher than the surrounding joint-fault intersection. The wide opening gap along the main fault allowed detailed observations of the fault planes at depth, which revealed (1) changing dips according to joint-fault angles, (2) slickenlines, (3) superimposed steepening fault-planes, causing sharp sawtooth-shaped structures. Comparison to a field analogue at Canyonlands National Park, Utah/USA showed similar structures and features such as vertical fault escarpments at the surface coinciding with joint-surfaces. In the field and in the models stepovers were observed as well as conjugate faulting and incremental fault-steepening.

The rotate-plus-shift C-arm trajectory: complete CT data with limited angular rotation

NASA Astrophysics Data System (ADS)

Ritschl, Ludwig; Kuntz, Jan; Kachelrieß, Marc

2015-03-01

In the last decade C-arm-based cone-beam CT became a widely used modality for intraoperative imaging. Typically a C-arm scan is performed using a circle-like trajectory around a region of interest. Therefor an angular range of at least 180° plus fan-angle must be covered to ensure a completely sampled data set. This fact defines some constraints on the geometry and technical specifications of a C-arm system, for example a larger C radius or a smaller C opening respectively. These technical modifications are usually not beneficial in terms of handling and usability of the C-arm during classical 2D applications like fluoroscopy. The method proposed in this paper relaxes the constraint of 180° plus fan-angle rotation to acquire a complete data set. The proposed C-arm trajectory requires a motorization of the orbital axis of the C and of ideally two orthogonal axis in the C plane. The trajectory consists of three parts: A rotation of the C around a defined iso-center and two translational movements parallel to the detector plane at the begin and at the end of the rotation. Combining these three parts to one trajectory enables for the acquisition of a completely sampled dataset using only 180° minus fan-angle of rotation. To evaluate the method we show animal and cadaver scans acquired with a mobile C-arm prototype. We expect that the transition of this method into clinical routine will lead to a much broader use of intraoperative 3D imaging in a wide field of clinical applications.

3. WIDE ANGLE OF NEUTRAL BUOYANCY SIMULATOR (NBS) FROM WITHIN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. WIDE ANGLE OF NEUTRAL BUOYANCY SIMULATOR (NBS) FROM WITHIN NBS HIGHBAY DOORS. DIVE BELL IN FOREGROUND. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

Evaluation of lens distortion errors in video-based motion analysis

NASA Technical Reports Server (NTRS)

Poliner, Jeffrey; Wilmington, Robert; Klute, Glenn K.; Micocci, Angelo

1993-01-01

In an effort to study lens distortion errors, a grid of points of known dimensions was constructed and videotaped using a standard and a wide-angle lens. Recorded images were played back on a VCR and stored on a personal computer. Using these stored images, two experiments were conducted. Errors were calculated as the difference in distance from the known coordinates of the points to the calculated coordinates. The purposes of this project were as follows: (1) to develop the methodology to evaluate errors introduced by lens distortion; (2) to quantify and compare errors introduced by use of both a 'standard' and a wide-angle lens; (3) to investigate techniques to minimize lens-induced errors; and (4) to determine the most effective use of calibration points when using a wide-angle lens with a significant amount of distortion. It was seen that when using a wide-angle lens, errors from lens distortion could be as high as 10 percent of the size of the entire field of view. Even with a standard lens, there was a small amount of lens distortion. It was also found that the choice of calibration points influenced the lens distortion error. By properly selecting the calibration points and avoidance of the outermost regions of a wide-angle lens, the error from lens distortion can be kept below approximately 0.5 percent with a standard lens and 1.5 percent with a wide-angle lens.

Faint Object Camera imaging and spectroscopy of NGC 4151

NASA Technical Reports Server (NTRS)

Boksenberg, A.; Catchpole, R. M.; Macchetto, F.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Crane, P.; Deharveng, J. M.; Disney, M. J.; Jakobsen, P.

1995-01-01

We describe ultraviolet and optical imaging and spectroscopy within the central few arcseconds of the Seyfert galaxy NGC 4151, obtained with the Faint Object Camera on the Hubble Space Telescope. A narrowband image including (O III) lambda(5007) shows a bright nucleus centered on a complex biconical structure having apparent opening angle approximately 65 deg and axis at a position angle along 65 deg-245 deg; images in bands including Lyman-alpha and C IV lambda(1550) and in the optical continuum near 5500 A, show only the bright nucleus. In an off-nuclear optical long-slit spectrum we find a high and a low radial velocity component within the narrow emission lines. We identify the low-velocity component with the bright, extended, knotty structure within the cones, and the high-velocity component with more confined diffuse emission. Also present are strong continuum emission and broad Balmer emission line components, which we attribute to the extended point spread function arising from the intense nuclear emission. Adopting the geometry pointed out by Pedlar et al. (1993) to explain the observed misalignment of the radio jets and the main optical structure we model an ionizing radiation bicone, originating within a galactic disk, with apex at the active nucleus and axis centered on the extended radio jets. We confirm that through density bounding the gross spatial structure of the emission line region can be reproduced with a wide opening angle that includes the line of sight, consistent with the presence of a simple opaque torus allowing direct view of the nucleus. In particular, our modelling reproduces the observed decrease in position angle with distance from the nucleus, progressing initially from the direction of the extended radio jet, through our optical structure, and on to the extended narrow-line region. We explore the kinematics of the narrow-line low- and high-velocity components on the basis of our spectroscopy and adopted model structure.

Energy Landscapes for the Self-Assembly of Supramolecular Polyhedra

NASA Astrophysics Data System (ADS)

Russell, Emily R.; Menon, Govind

2016-06-01

We develop a mathematical model for the energy landscape of polyhedral supramolecular cages recently synthesized by self-assembly (Sun et al. in Science 328:1144-1147, 2010). Our model includes two essential features of the experiment: (1) geometry of the organic ligands and metallic ions; and (2) combinatorics. The molecular geometry is used to introduce an energy that favors square-planar vertices (modeling {Pd}^{2+} ions) and bent edges with one of two preferred opening angles (modeling boomerang-shaped ligands of two types). The combinatorics of the model involve two-colorings of edges of polyhedra with four-valent vertices. The set of such two-colorings, quotiented by the octahedral symmetry group, has a natural graph structure and is called the combinatorial configuration space. The energy landscape of our model is the energy of each state in the combinatorial configuration space. The challenge in the computation of the energy landscape is a combinatorial explosion in the number of two-colorings of edges. We describe sampling methods based on the symmetries of the configurations and connectivity of the configuration graph. When the two preferred opening angles encompass the geometrically ideal angle, the energy landscape exhibits a very low-energy minimum for the most symmetric configuration at equal mixing of the two angles, even when the average opening angle does not match the ideal angle.

Satellite-Tracking Millimeter-Wave Reflector Antenna System For Mobile Satellite-Tracking

NASA Technical Reports Server (NTRS)

Densmore, Arthur C. (Inventor); Jamnejad, Vahraz (Inventor); Woo, Kenneth E. (Inventor)

2001-01-01

A miniature dual-band two-way mobile satellite-tracking antenna system mounted on a movable vehicle includes a miniature parabolic reflector dish having an elliptical aperture with major and minor elliptical axes aligned horizontally and vertically, respectively, to maximize azimuthal directionality and minimize elevational directionality to an extent corresponding to expected pitch excursions of the movable ground vehicle. A feed-horn has a back end and an open front end facing the reflector dish and has vertical side walls opening out from the back end to the front end at a lesser horn angle and horizontal top and bottom walls opening out from the back end to the front end at a greater horn angle. An RF circuit couples two different signal bands between the feed-horn and the user. An antenna attitude controller maintains an antenna azimuth direction relative to the satellite by rotating it in azimuth in response to sensed yaw motions of the movable ground vehicle so as to compensate for the yaw motions to within a pointing error angle. The controller sinusoidally dithers the antenna through a small azimuth dither angle greater than the pointing error angle while sensing a signal from the satellite received at the reflector dish, and deduces the pointing angle error from dither-induced fluctuations in the received signal.

A satellite-tracking millimeter-wave reflector antenna system for mobile satellite-tracking

NASA Technical Reports Server (NTRS)

Densmore, Arthur C. (Inventor); Jamnejad, Vahraz (Inventor); Woo, Kenneth E. (Inventor)

1995-01-01

A miniature dual-band two-way mobile satellite tracking antenna system mounted on a movable ground vehicle includes a miniature parabolic reflector dish having an elliptical aperture with major and minor elliptical axes aligned horizontally and vertically, respectively, to maximize azimuthal directionality and minimize elevational directionality to an extent corresponding to expected pitch excursions of the movable ground vehicle. A feed-horn has a back end and an open front end facing the reflector dish and has vertical side walls opening out from the back end to the front end at a lesser horn angle and horizontal top and bottom walls opening out from the back end to the front end at a greater horn angle. An RF circuit couples two different signal bands between the feed-horn and the user. An antenna attitude controller maintains an antenna azimuth direction relative to the satellite by rotating it in azimuth in response to sensed yaw motions of the movable ground vehicle so as to compensate for the yaw motions to within a pointing error angle. The controller sinusoidally dithers the antenna through a small azimuth dither angle greater than the pointing error angle while sensing a signal from the satellite received at the reflector dish, and deduces the pointing angle error from dither-induced fluctuations in the received signal.

Characteristics of Upper Quadrant Posture of Young Women with Temporomandibular Disorders

PubMed Central

Uritani, Daisuke; Kawakami, Tetsuji; Inoue, Tomohiro; Kirita, Tadaaki

2014-01-01

[Purpose] This study aimed to investigate the characteristics of upper quadrant posture of young women with temporomandibular disorders. [Subjects] The participants were 19 female patients with temporomandibular disorders (patient group: mean age, 30.1 years) and 14 controls (control group: mean age, 24.6 years). [Methods] Outcome measures were the neck inclination angle (formed by a line connecting C7 and the ear tragus with a horizontal line), the angle of the shoulder (formed by a line connecting C7 and the acromial angle with a horizontal line), the cranial rotation angle (formed by a line connecting the ear tragus and the corner of the eye with a horizontal line), and the neck-length/shoulder-width ratio [the ratio of the neck length (from C7 to the tragus) to the width of the shoulder between the acromial angle]. The maximum range of mouth opening was measured using a scale. [Results] The neck inclination angle and maximum range of mouth opening were significantly smaller in the patient group than in the control group. No significant differences were observed in the other outcome measures between the two groups. [Conclusion] Temporomandibular disorders with limited mouth opening in young females are associated with the head position relative to the trunk. PMID:25276038

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldstein, Adam; Connaughton, Valerie; Briggs, Michael S.

We present a method to estimate the jet opening angles of long duration gamma-ray bursts (GRBs) using the prompt gamma-ray energetics and an inversion of the Ghirlanda relation, which is a correlation between the time-integrated peak energy of the GRB prompt spectrum and the collimation-corrected energy in gamma-rays. The derived jet opening angles using this method and detailed assumptions match well with the corresponding inferred jet opening angles obtained when a break in the afterglow is observed. Furthermore, using a model of the predicted long GRB redshift probability distribution observable by the Fermi Gamma-ray Burst Monitor (GBM), we estimate themore » probability distributions for the jet opening angle and rest-frame energetics for a large sample of GBM GRBs for which the redshifts have not been observed. Previous studies have only used a handful of GRBs to estimate these properties due to the paucity of observed afterglow jet breaks, spectroscopic redshifts, and comprehensive prompt gamma-ray observations, and we potentially expand the number of GRBs that can be used in this analysis by more than an order of magnitude. In this analysis, we also present an inferred distribution of jet breaks which indicates that a large fraction of jet breaks are not observable with current instrumentation and observing strategies. We present simple parameterizations for the jet angle, energetics, and jet break distributions so that they may be used in future studies.« less

In Vivo Spinal Posture during Upright and Reclined Sitting in an Office Chair

PubMed Central

Zemp, Roland; Taylor, William R.; Lorenzetti, Silvio

2013-01-01

Increasing numbers of people spend the majority of their working lives seated in an office chair. Musculoskeletal disorders, in particular low back pain, resulting from prolonged static sitting are ubiquitous, but regularly changing sitting position throughout the day is thought to reduce back problems. Nearly all currently available office chairs offer the possibility to alter the backrest reclination angles, but the influence of changing seating positions on the spinal column remains unknown. In an attempt to better understand the potential to adjust or correct spine posture using adjustable seating, five healthy subjects were analysed in an upright and reclined sitting position conducted in an open, upright MRI scanner. The shape of the spine, as described using the vertebral bodies' coordinates, wedge angles, and curvature angles, showed high inter-subject variability between the two seating positions. The mean lumbar, thoracic, and cervical curvature angles were 29 ± 15°, −29 ± 4°, and 13 ± 8° for the upright and 33 ± 12°, −31 ± 7°, and 7 ± 7° for the reclined sitting positions. Thus, a wide range of seating adaptation is possible through modification of chair posture, and dynamic seating options may therefore provide a key feature in reducing or even preventing back pain caused by prolonged static sitting. PMID:24175307

Field Calibration of XAD-Based Passive Air Sampler on the Tibetan Plateau: Wind Influence and Configuration Improvement.

PubMed

Gong, Ping; Wang, Xiaoping; Liu, Xiande; Wania, Frank

2017-05-16

The passive air sampler based on XAD-2 resin (XAD-PAS) has proven useful for collecting atmospheric persistent organic pollutants (POPs) in remote regions. Whereas laboratory studies have shown that, due to the open bottom of its housing, the passive sampling rate (PSR) of the XAD-PAS is susceptible to wind and other processes causing air turbulence, the sampler has not been calibrated in the field at sites experiencing high winds. In this study, the PSRs of the XAD-PAS were calibrated at three sites on the Tibetan Plateau, covering a wide range in temperature (T), pressure (P) and wind speed (v). At sites with low wind speeds (i.e., in a forest and an urban site), the PSRs are proportional to the ratio T 1.75 / P; at windy sites with an average wind speed above 3 m/s, the influence of v on PSRs cannot be ignored. Moreover, the open bottom of the XAD-PAS housing causes the PSRs to be influenced by wind angle and air turbulence caused by sloped terrain. Field calibration, wind speed measurements, and computational fluid dynamics (CFD) simulations indicate that a modified design incorporating an air spoiler consisting of 4 metal sheets dampens the turbulence caused by wind angle and sloped terrain and caps the PSR at ∼5 m 3 /day, irrespective of ambient wind. Therefore, the original XAD-PAS with an open bottom is suitable for deployment in urban areas and other less windy places, the modified design is preferable in mountain regions and other places where air circulation is complicated and strong.

Cross Cell Sandwich Core

NASA Technical Reports Server (NTRS)

Ford, Donald B. (Inventor)

2004-01-01

A sandwich core comprises two faceplates separated by a plurality of cells. The cells are comprised of walls positioned at oblique angles relative to a perpendicular axis extending through the faceplates. The walls preferably form open cells and are constructed from open cells and are constructed from rows of ribbons. The walls may be obliquely angled relative to more than one plane extending through the perpendicular axis.

Heterogeneous growth-induced prestrain in the heart

PubMed Central

Genet, M.; Rausch, M.; Lee, L.C.; Choy, S.; Zhao, X.; Kassab, G.S.; Kozerke, S.; Guccione, J.M.; Kuhl, E.

2015-01-01

Even when entirely unloaded, biological structures are not stress-free, as shown by Y.C. Fung’s seminal opening angle experiment on arteries and the left ventricle. As a result of this prestrain, subject-specific geometries extracted from medical imaging do not represent an unloaded reference configuration necessary for mechanical analysis, even if the structure is externally unloaded. Here we propose a new computational method to create physiological residual stress fields in subject-specific left ventricular geometries using the continuum theory of fictitious configurations combined with a fixed-point iteration. We also reproduced the opening angle experiment on four swine models, to characterize the range of normal opening angle values. The proposed method generates residual stress fields which can reliably reproduce the range of opening angles between 8.7±1.8 and 16.6 ± 13.7 as measured experimentally. We demonstrate that including the effects of prestrain reduces the left ventricular stiffness by up to 40%, thus facilitating the ventricular filling, which has a significant impact on cardiac function. This method can improve the fidelity of subject-specific models to improve our understanding of cardiac diseases and to optimize treatment options. PMID:25913241

Refraction and scattering of sound by a shear layer

NASA Technical Reports Server (NTRS)

Schlinker, R. H.; Amiet, R. K.

1980-01-01

The angle and amplitude changes for acoustic waves refracted by a circular open jet shear layer were determined. The generalized refraction theory was assessed experimentally for on axis and off axis acoustic source locations as source frequency varied from 1 kHz to 10 kHz and free stream Mach number varied from 0.1 to 0.4. Angle and amplitude changes across the shear layer show good agreement with theory. Experiments confirm that the refraction theory is independent of shear layer thickness, acoustic source frequency, and source type. A generalized theory is, thus, available for correcting far field noise data acquired in open jet test facilities. The effect of discrete tone scattering by the open jet turbulent shear layer was also studied. Scattering effects were investigated over the same Mach number range as frequency varied from 5 kHz to 15 kHz. Attenuation of discrete tone amplitude and tone broadening were measured as a function of acoustic source position and radiation angle. Scattering was found to be stronger at angles close to the open jet axis than at 90 deg, and becomes stronger as the acoustic source position shifts downstream. A scattering analysis provided an estimate of the onset of discrete tone scattering.

Retrobulbar hemodynamic parameters in men and women with open angle glaucoma.

PubMed

Marjanović, Ivan; Marjanović, Marija; Gvozdenović, Ranko; Risović, Dušica

2014-12-01

Several factors may have influence on systemic circulation. Additionally, peripheral circulation also demonstrates sex differences, in young women presenting significantly lower finger blood flow in comparison to men of the same age, a finding that disappears in women after menopause. The aim of this study was to compare the retrobulbar hemodynamic parameters measured by means of color Doppler imaging in women and men with open-angle glaucoma and elevated intraocular pressure. A total of 52 eyes from 52 open-angle glaucoma (OAG) patients, with elevated intraocular pressure (lOP), were included in this cross-sectional study. Peak-systolic velocity (PSV), end-diastolic velocity (EDV), and Pourcelot resistivity index (RI) were assessed in the ophtalmic artery (OA), central retinal artery (CRA), and posterior cilliary arteries (PCA). IOP was measured both with Goldmann Applanation tonometer (GAT) and with the dynamic contour tonometer (DCT), three times respectively. Ocular pulse amplitude (OPA) appeared during the DCT measurement. The retrobulbar hemodynamic parameters did not show any difference between men and post-menopausal women. The results of our study did not find any difference between sexes in patients with open-angle glaucoma and elevated intraocular pressure.

Accurate Analysis of Target Characteristic in Bistatic SAR Images: A Dihedral Corner Reflectors Case.

PubMed

Ao, Dongyang; Li, Yuanhao; Hu, Cheng; Tian, Weiming

2017-12-22

The dihedral corner reflectors are the basic geometric structure of many targets and are the main contributions of radar cross section (RCS) in the synthetic aperture radar (SAR) images. In stealth technologies, the elaborate design of the dihedral corners with different opening angles is a useful approach to reduce the high RCS generated by multiple reflections. As bistatic synthetic aperture sensors have flexible geometric configurations and are sensitive to the dihedral corners with different opening angles, they specially fit for the stealth target detections. In this paper, the scattering characteristic of dihedral corner reflectors is accurately analyzed in bistatic synthetic aperture images. The variation of RCS with the changing opening angle is formulated and the method to design a proper bistatic radar for maximizing the detection capability is provided. Both the results of the theoretical analysis and the experiments show the bistatic SAR could detect the dihedral corners, under a certain bistatic angle which is related to the geometry of target structures.

Accurate Analysis of Target Characteristic in Bistatic SAR Images: A Dihedral Corner Reflectors Case

PubMed Central

Ao, Dongyang; Hu, Cheng; Tian, Weiming

2017-01-01

The dihedral corner reflectors are the basic geometric structure of many targets and are the main contributions of radar cross section (RCS) in the synthetic aperture radar (SAR) images. In stealth technologies, the elaborate design of the dihedral corners with different opening angles is a useful approach to reduce the high RCS generated by multiple reflections. As bistatic synthetic aperture sensors have flexible geometric configurations and are sensitive to the dihedral corners with different opening angles, they specially fit for the stealth target detections. In this paper, the scattering characteristic of dihedral corner reflectors is accurately analyzed in bistatic synthetic aperture images. The variation of RCS with the changing opening angle is formulated and the method to design a proper bistatic radar for maximizing the detection capability is provided. Both the results of the theoretical analysis and the experiments show the bistatic SAR could detect the dihedral corners, under a certain bistatic angle which is related to the geometry of target structures. PMID:29271917

Broadband and wide angle near-unity absorption in graphene-insulator-metal thin film stacks

NASA Astrophysics Data System (ADS)

Zhang, H. J.; Zheng, G. G.; Chen, Y. Y.; Xu, L. H.

2018-05-01

Broadband unity absorption in graphene-insulator-metal (GIM) structures is demonstrated in the visible (VIS) and near-infrared (NIR) spectra. The spectral characteristics possess broadband absorption peaks, by simply choosing a stack of GIM, while no nanofabrication steps and patterning are required, and thus can be easily fabricated to cover a large area. The electromagnetic (EM) waves can be entirely trapped and the absorption can be greatly enhanced are verified with the finite-difference time-domain (FDTD) and rigorous coupled wave analysis (RCWA) methods. The position and the number of the absorption peak can be totally controlled by adjusting the thickness of the insulator layer. The proposed absorber maintains high absorption (above 90%) for both transverse electric (TE) and transverse magnetic (TM) polarizations, and for angles of incidence up to 80°. This work opens up a promising approach to realize perfect absorption (PA) with ultra-thin film, which could implicate many potential applications in optical detection and optoelectronic devices.

--No Title--

Science.gov Websites

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Twist-3 contributions to wide-angle photoproduction of pions

NASA Astrophysics Data System (ADS)

Kroll, P.; Passek-Kumerički, K.

2018-04-01

We investigate wide-angle π0 photoproduction within the handbag approach to twist-3 accuracy. In contrast to earlier work both the 2-particle as well as the 3-particle twist-3 contributions are taken into account. It is shown that both are needed for consistent results that respect gauge invariance and crossing properties. The numerical studies reveal the dominance of the twist-3 contribution. With it fair agreement with the recent CLAS measurement of the π0 cross section is obtained. We briefly comment also on wide-angle photoproduction of other pseudoscalar mesons.

Aerodynamic Load Measurements and Opening Characteristics of Automatic Leading Edge Slats on a 45 deg Sweptback Wing at Transonic Speeds

NASA Technical Reports Server (NTRS)

Arabian, Donald D.; Runckel, Jack F.; Reid, Charles F, Jr.

1961-01-01

Measurements of the normal force and chord force were made on the slats of a sting-mounted wing-fuselage model through a Mach number range of 0.60 to 1.03 and at angles of attack from 0 to 20 deg at subsonic speeds and from 0 to 8 deg at Mach number 1.03. The 20-percent-chord tapered leading-edge slats extended from 25 to 95 percent of the semispan and consisted of five segments. The model wing had 45 deg sweep, an aspect ratio of 3.56, a taper ratio of 0.3, and NACA 64(06)AO07 airfoil sections. Slat forces and moments were determined for the slats in the almost-closed and open positions for spanwise extents of 35 to 95 percent and 46 to 95 percent of the semispan. The results of the investigation showed little change in the slat maximum force and moment coefficients with Mach number. The coefficients for the open and almost-closed slat positions had similar variations with angle of attack. The loads on the individual slat segments were found to increase toward the tip for moderate angles of attack and decrease toward the tip for high angles of attack. An analysis of the opening and closing characteristics of aerodynamically operated slats opening on a circular-arc path is included.

A mechanical analysis of conduit arteries accounting for longitudinal residual strains.

PubMed

Wang, Ruoya; Gleason, Rudolph L

2010-04-01

Identification of an appropriate stress-free reference configuration is critically important in providing a reasonable prediction of the intramural stress distribution when performing biomechanical analyses on arteries. The stress-free state is commonly approximated as a radially cut ring that typically opens into a nearly circular sector, relieving much of the circumferential residual strains that exist in the traction-free configuration. An opening angle is often used to characterize this sector. In this study, we first present experimental results showing significant residual deformations in the longitudinal direction of two commonly studied arteries in the pig: the common carotid artery and the left anterior descending coronary artery. We concluded that a radially cut ring cannot completely describe the stress-free state of the arteries. Instead, we propose the use of a longitudinal opening angle, in conjunction with the traditional circumferential opening angle, to experimentally quantify the stress-free state of an artery. Secondly, we propose a new kinematic model to account for the addition of longitudinal residual strains through employing the longitudinal opening angle and performed a stress analysis. We found that with the inclusion of longitudinal residual strains in the stress analysis, the predicted circumferential stress gradient was decreased by 3-fold and the predicted longitudinal stress gradient was increased by 5.7-fold. Thus, inclusion of longitudinal residual strains has a significant effect on the predicted stress distribution in arteries.

The effect of internal fixation lamp on anterior chamber angle width measured by anterior segment optical coherence tomography.

PubMed

Nakamine, Sakari; Sakai, Hiroshi; Arakaki, Yoshikuni; Yonahara, Michiko; Kaiya, Tadayoshi

2018-01-01

To study the effect of the internal fixation lamp on anterior chamber width measured by anterior segment optical coherence tomography. In a prospective cross sectional observational study, consecutive 22 right eyes of 22 patients (4 men and 18 women) with suspected primary angle closure underwent swept source domain anterior segment optical coherence tomography (AS-OCT), (CASIA SS-1000, Tomey, Nagoya, Japan). Anterior chamber parameters of angle opening distance (AOD), trabecular-iris angle (TIA), angle recess area (ARA) at 500 or 750 µm from scleral spur and pupil diameter were measured by AS-OCT in a three-dimensional mode in 4 quadrants (superior, inferior, temporal and nasal) in dark room setting both with and without internal fixation lamp. Anterior segment parameters of AOD 500 in superior, inferior and temporal quadrants, AOD 750 at superior and nasal, TIA 500 at superior, and inferior and TIA 750 at superior and nasal, and ARA 500 or 750 at superior and inferior with internal fixation lamp were greater and the pupil diameter was significantly (all P < 0.05, paired t test) smaller than when measured without fixation lamp. Internal fixation lamp of the anterior segment OCT makes the pupil constrict and angle wider. When using AS-OCT with usual setting with internal fixation lamp on with eyes in which the anterior chamber angle is narrow but open, it is recommended that the internal fixation lamp be turned off to ensure a clear indication as to whether the angle is open or closed in the dark.

Genome-wide association study of intraocular pressure identifies the GLCCI1/ICA1 region as a glaucoma susceptibility locus

PubMed Central

Strange, Amy; Bellenguez, Céline; Sim, Xueling; Luben, Robert; Hysi, Pirro G.; Ramdas, Wishal D.; van Koolwijk, Leonieke M.E.; Freeman, Colin; Pirinen, Matti; Su, Zhan; Band, Gavin; Pearson, Richard; Vukcevic, Damjan; Langford, Cordelia; Deloukas, Panos; Hunt, Sarah; Gray, Emma; Dronov, Serge; Potter, Simon C.; Tashakkori-Ghanbaria, Avazeh; Edkins, Sarah; Bumpstead, Suzannah J.; Blackwell, Jenefer M.; Bramon, Elvira; Brown, Matthew A.; Casas, Juan P.; Corvin, Aiden; Duncanson, Audrey; Jankowski, Janusz A.Z.; Markus, Hugh S.; Mathew, Christopher G.; Palmer, Colin N.A.; Plomin, Robert; Rautanen, Anna; Sawcer, Stephen J.; Trembath, Richard C.; Wood, Nicholas W.; Barroso, Ines; Peltonen, Leena; Healey, Paul; McGuffin, Peter; Topouzis, Fotis; Klaver, Caroline C.W.; van Duijn, Cornelia M.; Mackey, David A.; Young, Terri L.; Hammond, Christopher J.; Khaw, Kay-Tee; Wareham, Nick; Wang, Jie Jin; Wong, Tien Y.; Foster, Paul J.; Mitchell, Paul; Spencer, Chris C.A.; Donnelly, Peter; Viswanathan, Ananth C.

2013-01-01

To discover quantitative trait loci for intraocular pressure, a major risk factor for glaucoma and the only modifiable one, we performed a genome-wide association study on a discovery cohort of 2175 individuals from Sydney, Australia. We found a novel association between intraocular pressure and a common variant at 7p21 near to GLCCI1 and ICA1. The findings in this region were confirmed through two UK replication cohorts totalling 4866 individuals (rs59072263, Pcombined = 1.10 × 10−8). A copy of the G allele at this SNP is associated with an increase in mean IOP of 0.45 mmHg (95%CI = 0.30–0.61 mmHg). These results lend support to the implication of vesicle trafficking and glucocorticoid inducibility pathways in the determination of intraocular pressure and in the pathogenesis of primary open-angle glaucoma. PMID:23836780

Recent advancements of wide-angle polarization analysis with 3He neutron spin filters

NASA Astrophysics Data System (ADS)

Chen, W. C.; Gentile, T. R.; Ye, Q.; Kirchhoff, A.; Watson, S. M.; Rodriguez-Rivera, J. A.; Qiu, Y.; Broholm, C.

2016-09-01

Wide-angle polarization analysis with polarized 3He based neutron spin filters (NSFs) has recently been employed on the Multi-Axis Crystal Spectrometer (MACS) at the National Institute of Standards and Technology Center for Neutron Research (NCNR). Over the past several years, the apparatus has undergone many upgrades to address the fundamental requirements for wide angle polarization analysis using spin exchange optical pumping based 3He NSFs. In this paper, we report substantial improvements in the on-beam-line performance of the apparatus and progress toward routine user capability. We discuss new standard samples used for 3He NSF characterization and the flipping ratio measurement on MACS. We further discuss the management of stray magnetic fields produced by operation of superconducting magnets on the MACS instrument, which can significantly reduce the 3He polarization relaxation time. Finally, we present the results of recent development of horseshoe-shaped wide angle cells.

A New Structural Model for the Red Sea from Seismic Data

NASA Astrophysics Data System (ADS)

Mooney, W. D.; Yao, Z.; Zahran, H. M.; El-Hadidy, S. Y.

2017-12-01

We present a new structureal model for the Red Sea that shows opening on an east-dipping low-angle detachment fault. We measured phase velocities using Rayleigh-wave data recorded at recently-installed, dense broadband seismic stations in the Arabian shield and determined the shear-wave velocity structure. Our results clearly reveal a 300-km wide upper mantle seismic low-velocity zone (LVZ) beneath the western Arabian shield at a depth of 60 km and with a thickness of 130 km. The LVZ has a north-south trend and follows the late-Cenozoic volcanic areas. The lithosphere beneath the western Arabian shield is remarkably thin (60-90 km). The 130-km thick mantle LVZ does not appear beneath the western Red Sea and the spreading axis. Thus, the Red Sea at 20°- 26° N is an asymmetric rift, with thin lithosphere located east of the Red Sea axis, as predicted by the low-angle detachment model for rift development. Passive rifting at the Red Sea and extensional stresses in the shield are probably driven by slab pull from the Zagros subduction zone. The low shear-wave velocity (4.0-4.2 km/s) and the geometry of LVZ beneath the western shield indicate northward flow of hot asthenosphere from the Afar hot spot. The upwelling of basaltic melt in fractures or zones of localized lithospheric thinning has produced extensive late Cenozoic volcanism on the western edge of the shield, and the buoyant LVZ has caused pronounced topography uplift there. Thus, the evolution of the Red Sea and the Arabian shield is driven by subduction of the Arabian plate along its northeastern boundary, and the Red Sea opened on a east-dipping low-angle detachment fault.

[Effects of nootropic agents on visual functions and lacrimal antioxidative activity in patients with primary open-angle glaucoma].

PubMed

Davydova, N G; Kuznetsova, T P; Borisova, S A; Abdulkadyrova, M Zh

2006-01-01

The paper presents the results of an investigation of the effect of the nootropic agents pantogam and nooclerine on visual functions in patients with primary open-angle glaucoma. These agents have been found to have a beneficial effect on the functional activity of the retina and optic nerve, light sensitivity, hemo- and hydrodynamics of the eye.

Wide-angle Spectrally Selective Perfect Absorber by Utilizing Dispersionless Tamm Plasmon Polaritons

PubMed Central

Xue, Chun-hua; Wu, Feng; Jiang, Hai-tao; Li, Yunhui; Zhang, Ye-wen; Chen, Hong

2016-01-01

We theoretically investigate wide-angle spectrally selective absorber by utilizing dispersionless Tamm plasmon polaritons (TPPs) under TM polarization. TPPs are resonant tunneling effects occurring on the interface between one-dimensional photonic crystals (1DPCs) and metal slab, and their dispersion properties are essentially determined by that of 1DPCs. Our investigations show that dispersionless TPPs can be excited in 1DPCs containing hyperbolic metamaterials (HMMs) on metal substrate. Based on dispersionless TPPs, electromagnetic waves penetrate into metal substrate and are absorbed entirely by lossy metal, exhibiting a narrow-band and wide-angle perfect absorption for TM polarization. Our results exhibit nearly perfect absorption with a value over 98% in the angle of incidence region of 0–80 degree. PMID:27991565

Pathophysiology of primary open-angle glaucoma from a neuroinflammatory and neurotoxicity perspective: a review of the literature.

PubMed

Evangelho, Karine; Mogilevskaya, Maria; Losada-Barragan, Monica; Vargas-Sanchez, Jeinny Karina

2017-12-30

Glaucoma is the leading cause of blindness in humans, affecting 2% of the population. This disorder can be classified into various types including primary, secondary, glaucoma with angle closure and with open angle. The prevalence of distinct types of glaucoma differs for each particular region of the world. One of the most common types of this disease is primary open-angle glaucoma (POAG), which is a complex inherited disorder characterized by progressive retinal ganglion cell death, optic nerve head excavation and visual field loss. Nowadays, POAG is considered an optic neuropathy, while intraocular pressure is proposed to play a fundamental role in its pathophysiology and especially in optic disk damage. However, the exact mechanism of optic nerve head damage remains a topic of debate. This literature review aims to bring together the information on the pathophysiology of primary open-angle glaucoma, particularly focusing on neuroinflammatory mechanisms leading to the death of the retinal ganglion cell. A literature search was done on PubMed using key words including primary open-angle glaucoma, retinal ganglion cells, Müller cells, glutamate, glial cells, ischemia, hypoxia, exitotoxicity, neuroinflammation, axotomy and neurotrophic factors. The literature was reviewed to collect the information published about the pathophysiologic mechanisms of RGC death in the POAG, from a neuroinflammatory and neurotoxicity perspective. Proposed mechanisms for glaucomatous damage are a result of pressure in RGC followed by ischemia, hypoxia of the ONH, and consequently death due to glutamate-induced excitotoxicity, deprivation of energy and oxygen, increase in levels of inflammatory mediators and alteration of trophic factors flow. These events lead to blockage of anterograde and retrograde axonal transport with ensuing axotomy and eventually blindness. The damage to ganglion cells and eventually glaucomatous injury can occur via various mechanisms including baric trauma, ischemia and impact of metabolic toxins, which triggers an inflammatory process and secondary degeneration in the ONH.

Deep structure of the continental margin and basin off Greater Kabylia, Algeria - New insights from wide-angle seismic data modeling and multichannel seismic interpretation

NASA Astrophysics Data System (ADS)

Aïdi, Chafik; Beslier, Marie-Odile; Yelles-Chaouche, Abdel Karim; Klingelhoefer, Frauke; Bracene, Rabah; Galve, Audrey; Bounif, Abdallah; Schenini, Laure; Hamai, Lamine; Schnurle, Philippe; Djellit, Hamou; Sage, Françoise; Charvis, Philippe; Déverchère, Jacques

2018-03-01

During the Algerian-French SPIRAL survey aimed at investigating the deep structure of the Algerian margin and basin, two coincident wide-angle and reflection seismic profiles were acquired in central Algeria, offshore Greater Kabylia, together with gravimetric, bathymetric and magnetic data. This 260 km-long offshore-onshore profile spans the Balearic basin, the central Algerian margin and the Greater Kabylia block up to the southward limit of the internal zones onshore. Results are obtained from modeling and interpretation of the combined data sets. The Algerian basin offshore Greater Kabylia is floored by a thin oceanic crust ( 4 km) with P-wave velocities ranging between 5.2 and 6.8 km/s. In the northern Hannibal High region, the atypical 3-layer crustal structure is interpreted as volcanic products stacked over a thin crust similar to that bordering the margin and related to Miocene post-accretion volcanism. These results support a two-step back-arc opening of the west-Algerian basin, comprising oceanic crust accretion during the first southward stage, and a magmatic and probably tectonic reworking of this young oceanic basement during the second, westward, opening phase. The structure of the central Algerian margin is that of a narrow ( 70 km), magma-poor rifted margin, with a wider zone of distal thinned continental crust than on the other margin segments. There is no evidence for mantle exhumation in the sharp ocean-continent transition, but transcurrent movements during the second opening phase may have changed its initial geometry. The Plio-Quaternary inversion of the margin related to ongoing convergence between Africa and Eurasia is expressed by a blind thrust system under the margin rising toward the surface at the slope toe, and by an isostatic disequilibrium resulting from opposite flexures of two plates decoupled at the continental slope. This disequilibrium is likely responsible for the peculiar asymmetrical shape of the crustal neck that may thus be a characteristic feature of inverted rifted margins.

Opening of the Central Atlantic Ocean: Implications for Geometric Rifting and Asymmetric Initial Seafloor Spreading after Continental Breakup

NASA Astrophysics Data System (ADS)

Klingelhoefer, F.; Biari, Y.; Sahabi, M.; Funck, T.; Benabdellouahed, M.; Schnabel, M.; Reichert, C. J.; Gutscher, M. A.; Bronner, A.; Austin, J. A., Jr.

2017-12-01

The structure of conjugate passive margins provides information about rifting styles, the initial phases of the opening of an ocean and the formation of its associated sedimentary basins. The study of the deep structure of conjugate passive continental margins combined with precise plate kinematic reconstructions can provide constraints on the mechanisms of rifting and formation of initial oceanic crust. In this study the Central Atlantic conjugate margins are compared, based on compilation of wide-angle seismic profiles from the NW-Africa Nova Scotian and US passive margins. Plate cinematic reconstructions were used to place the profiles in the position at opening and at the M25 magnetic anomaly. The patterns of volcanism, crustal thickness, geometry, and seismic velocities in the transition zone. suggest symmetric rifting followed by asymmetric oceanic crustal accretion. Conjugate profiles in the southern Central Atlantic image differences in the continental crustal thickness. While profiles on the eastern US margin are characterized by thick layers of magmatic underplating, no such underplate was imaged along the NW-African continental margin. It has been proposed that these volcanic products form part of the CAMP (Central Atlantic Magmatic Province). In the north, two wide-angle seismic profiles acquired in exactly conjugate positions show that the crustal geometry of the unthinned continental crust and the necking zone are nearly symmetric. A region including seismic velocities too high to be explained by either continental or oceanic crust is imaged along the Nova Scotia margin off Eastern Canada, corresponding on the African side to an oceanic crust with slightly elevated velocities. These might result from asymmetric spreading creating seafloor by faulting the existing lithosphere on the Canadian side and the emplacement of magmatic oceanic crust including pockets of serpentinite on the Moroccan margin. A slightly elevated crustal thickness along the African margin can be explained by the influence of the Canary hotspot between 60 and 30 Ma in the study region. After isochron M25, a large-scale plate reorganization may then have led to an increase in spreading velocity and the production of a more typical but thin magmatic crust on both sides.

Design of a polarization-independent, wide-angle, broadband visible absorber

NASA Astrophysics Data System (ADS)

Jia, Xiuli; Wang, Xiaoou

2018-01-01

Many optical systems benefit from elements that can absorb a broad range of wavelengths over a wide range of angles, independent of polarization. In this paper, we present a polarization-independent, wide-angle, broadband absorber in the visible regime that exploits strong symmetric and asymmetric resonance modes of electromagnetic dipoles. It makes use of a bilayer cross-pattern structure which is simple, having five layers that include two stacks of metal ribbon in cross-patterns, two dielectric spacers and a metal reflecting layer. Simulations show that the design exhibits a significantly enhanced absorption property when compared to a device with a bilayer metal film structure or any other complex structure of cross-patterns that have no intersection angle. The maximum absorption efficiency of the device is 100% at resonances, and its absorption characteristics can be maintained over a wide range of angles of incidence - up to ± 60° - regardless of the incident polarization. This strategy can, in principle, be applied to other material systems and could be useful in diverse applications, including thermal emitters, photovoltaics and photodetectors.

The relationship between the fistula tract and the facial nerve in type II first branchial cleft anomalies.

PubMed

Ertas, Burak; Gunaydin, Rıza Onder; Unal, Omer Faruk

2015-04-01

To share our experience involving seven patients with type II first branchial cleft anomalies (hereafter, type II anomalies), to determine whether the location of the external fistula openings of the anomalies are associated with the location of the facial nerve tract, and elucidate the relationship between the location of the fistula opening and the facial nerve. The medical records of seven patients who underwent surgery from 2005 to 2013 for type II anomalies were retrospectively examined. The relationship between the fistula opening and the facial nerve was evaluated in each patient with respect to whether the fistula opening was superior or inferior to the mandibular angle. All patients underwent partial parotidectomy, facial nerve exposure, and total excision of the mass together with connection of a small cuff of the external auditory canal skin to the fistula tract. The fistula tracts were located medially to the facial nerve in two patients, and both fistulae had openings inferior to the mandibular angle. The fistula tracts were located laterally to the facial nerve in the remaining five patients: one patient had no external opening, one had an opening inferior to the mandibular angle, and the remaining three had openings superior to the mandibular angle. Because type II anomalies are rare, their diagnosis is difficult. Surgery of such lesions is challenging and associated with a high risk due to their proximity to the facial nerve. We believe that the location of the fistula opening may help to identify the relationship between the anomalous lesion and facial nerve. Studies involving larger series of cases are needed to confirm our hypothesis; however, because of the rarity of this specific anomaly, it will not be easy to compile a large number of cases. We believe that our study will encourage further investigation on this subject. Copyright © 2014. Published by Elsevier Ireland Ltd.

Comparison of Dimensional Accuracy between Open-Tray and Closed-Tray Implant Impression Technique in 15° Angled Implants

PubMed Central

Balouch, F; Jalalian, E; Nikkheslat, M; Ghavamian, R; Toopchi, Sh; Jallalian, F; Jalalian, S

2013-01-01

Statement of Problem: Various impression techniques have different effects on the accuracy of final cast dimensions. Meanwhile; there are some controversies about the best technique. Purpose: This study was performed to compare two kinds of implant impression methods (open tray and closed tray) on 15 degree angled implants. Materials and Method: In this experimental study, a steel model with 8 cm in diameter and 3 cm in height were produced with 3 holes devised inside to stabilize 3 implants. The central implant was straight and the other two implants were 15° angled. The two angled implants had 5 cm distance from each other and 3.5 cm from the central implant. Dental stone, high strength (type IV) was used for the main casts. Impression trays were filled with poly ether, and then the two impression techniques (open tray and closed tray) were compared. To evaluate positions of the implants, each cast was analyzed by CMM device in 3 dimensions (x,y,z). Differences in the measurements obtained from final casts and laboratory model were analyzed using t-Test. Results: The obtained results indicated that closed tray impression technique was significantly different in dimensional accuracy when compared with open tray method. Dimensional changes were 129 ± 37μ and 143.5 ± 43.67μ in closed tray and open tray, while coefficient of variation in closed- tray and open tray were reported to be 27.2% and 30.4%, respectively. Conclusion: Closed impression technique had less dimensional changes in comparison with open tray method, so this study suggests that closed tray impression technique is more accurate. PMID:24724130

Holographic Jet Shapes and their Evolution in Strongly Coupled Plasma

NASA Astrophysics Data System (ADS)

Brewer, Jasmine; Rajagopal, Krishna; Sadofyev, Andrey; van der Schee, Wilke

2017-11-01

Recently our group analyzed how the probability distribution for the jet opening angle is modified in an ensemble of jets that has propagated through an expanding cooling droplet of plasma [K. Rajagopal, A. V. Sadofyev, W. van der Schee, Phys. Rev. Lett. 116 (2016) 211603]. Each jet in the ensemble is represented holographically by a string in the dual 4+1- dimensional gravitational theory with the distribution of initial energies and opening angles in the ensemble given by perturbative QCD. In [K. Rajagopal, A. V. Sadofyev, W. van der Schee, Phys. Rev. Lett. 116 (2016) 211603], the full string dynamics were approximated by assuming that the string moves at the speed of light. We are now able to analyze the full string dynamics for a range of possible initial conditions, giving us access to the dynamics of holographic jets just after their creation. The nullification timescale and the features of the string when it has nullified are all results of the string evolution. This emboldens us to analyze the full jet shape modification, rather than just the opening angle modification of each jet in the ensemble as in [K. Rajagopal, A. V. Sadofyev, W. van der Schee, Phys. Rev. Lett. 116 (2016) 211603]. We find the result that the jet shape scales with the opening angle at any particular energy. We construct an ensemble of dijets with energies and energy asymmetry distributions taken from events in proton-proton collisions, opening angle distribution as in [K. Rajagopal, A. V. Sadofyev, W. van der Schee, Phys. Rev. Lett. 116 (2016) 211603], and jet shape taken from proton-proton collisions and scaled according to our result. We study how these observables are modified after we send the ensemble of dijets through the strongly-coupled plasma.

Are we ready for genetic testing for primary open-angle glaucoma?

PubMed

Khawaja, Anthony P; Viswanathan, Ananth C

2018-05-01

Following a dramatic reduction in the cost of genotyping technology in recent years, there have been significant advances in the understanding of the genetic basis of glaucoma. Glaucoma patients represent around a quarter of all outpatient activity in the UK hospital eye service and are a huge burden for the National Health Service. A potential benefit of genetic testing is personalised glaucoma management, allowing direction of our limited healthcare resources to the glaucoma patients who most need it. Our review aims to summarise recent discoveries in the field of glaucoma genetics and to discuss their potential clinical utility. While genome-wide association studies have now identified over ten genes associated with primary open-angle glaucoma (POAG), individually, variants in these genes are not predictive of POAG in populations. There are data suggesting some of these POAG variants are associated with conversion from ocular hypertension to POAG and visual field progression among POAG patients. However, these studies have not been replicated yet and such genetic testing is not currently justified in clinical care. In contrast, genetic testing for inherited early-onset disease in relatives of POAG patients with a known genetic mutation is of clear benefit; this can support either regular review to commence early treatment when the disease develops, or discharge from ophthalmology services of relatives who do not carry the mutation. Genetic testing for POAG at a population level is not currently justified.

Using Digital Technology to See Angles from Different Angles. Part 2: Openings and Turns

ERIC Educational Resources Information Center

Host, Erin; Baynham, Emily; McMaster, Heather

2015-01-01

Ever wondered how to use technology to teach angles? This article follows on from an earlier article published last year, providing a range of ideas for integrating technology and concrete materials with the teaching of angle concepts. The authors also provide a comprehensive list of free online games and learning objects that can be used to teach…

Investigation of pH response and photo-control of wettability on spiropyran-derivatized surfaces

NASA Astrophysics Data System (ADS)

Park, Choong-Do

2009-12-01

One promising method to control a liquid drop on a surface for microfluidic devices is to use the surface tension gradient on a photo-responsive surface by light irradiation. A photo-switchable spiropyran monolayer was prepared on smooth glass or silicon wafers via 3-aminopropylmethyldiethoxysilane linkages. The pH response of the surface-bound spiropyran was investigated by measuring contact angle as a function of pH, since the pH value of the liquids applied to a microfluidic system can vary widely. Based on the contact angle titration and UV-Vis spectroscopic data, a protonation and deprotonation mechanism of the surface-bound spiropyran was proposed. The advancing contact angles under UV and under visible light irradiation at high pH values were about 100 smaller than those at low pH values. The decrease in contact angle under UV light with decreasing pH value was assigned to the protonation of open merocyanine (MC) to MC-OH+. Meanwhile, the decrease in contact angle under visible light was attributed to the protonation of the closed spiropryan (SP), generating a mixed state of MC-OH+ in equilibrium with N-protonated SP-NH+. In order to examine the possibility of light-induced liquid drop motion on the spiropyran-derivatized smooth surfaces, the light-induced surface tension change between SP and MC was estimated using the contact angle hysteresis (CAH) and the Lifshitz---van der Waals/Acid-Base (LWAB) approaches based on the contact angle data. The average light-induced surface energy change between the two isomers under UV and visible light exposure was 1.4 mJ/m 2, implying that the small change in surface tension is not sufficient to move a liquid droplet on the surface. Liquid drop motion requires that the light-induced switching angle be greater than the contact angle hysteresis. However, the light-induced switching angle of the spiropyran-derivatized surface was significantly smaller than the hysteresis. Thus, in order to achieve liquid drop motion on the spiropyran-derivatized surface, a new surface design which employs a combination of chemical modification of a hydrophobic organosilane and micropatterned rough surface morphology was suggested.

Minimally Invasive and Open Distal Chevron Osteotomy for Mild to Moderate Hallux Valgus.

PubMed

Brogan, Kit; Lindisfarne, Edward; Akehurst, Harold; Farook, Usama; Shrier, Will; Palmer, Simon

2016-11-01

Minimally invasive surgical (MIS) techniques are increasingly being used in foot and ankle surgery but it is important that they are adopted only once they have been shown to be equivalent or superior to open techniques. We believe that the main advantages of MIS are found in the early postoperative period, but in order to adopt it as a technique longer-term studies are required. The aim of this study was to compare the 2-year outcomes of a third-generation MIS distal chevron osteotomy with a comparable traditional open distal chevron osteotomy for mild-moderate hallux valgus. Our null hypothesis was that the 2 techniques would yield equivalent clinical and radiographic results at 2 years. This was a retrospective cohort study. Eighty-one consecutive feet (49 MIS and 32 open distal chevron osteotomies) were followed up for a minimum 24 months (range 24-58). All patients were clinically assessed using the Manchester-Oxford Foot Questionnaire. Radiographic measures included hallux valgus angle, the intermetatarsal angle, hallux interphalangeal angle, metatarsal phalangeal joint angle, distal metatarsal articular angle, tibial sesamoid position, shape of the first metatarsal head, and plantar offset. Statistical analysis was done using Student t test or Wilcoxon rank-sum test for continuous data and Pearson chi-square test for categorical data. Clinical and radiologic postoperative scores in all domains were substantially improved in both groups (P < .001), but there was no statistically significant difference in improvement of any domain between open and MIS groups (P > .05). There were no significant differences in complications between the 2 groups ( > .5). The midterm results of this third-generation technique show that it was a safe procedure with good clinical outcomes and comparable to traditional open techniques for symptomatic mild-moderate hallux valgus. Level III, retrospective comparative study. © The Author(s) 2016.

Photometric theory for wide-angle phenomena

NASA Technical Reports Server (NTRS)

Usher, Peter D.

1990-01-01

An examination is made of the problem posed by wide-angle photographic photometry, in order to extract a photometric-morphological history of Comet P/Halley. Photometric solutions are presently achieved over wide angles through a generalization of an assumption-free moment-sum method. Standard stars in the field allow a complete solution to be obtained for extinction, sky brightness, and the characteristic curve. After formulating Newton's method for the solution of the general nonlinear least-square problem, an implementation is undertaken for a canonical data set. Attention is given to the problem of random and systematic photometric errors.

Agreement between image grading of conventional (45°) and ultra wide-angle (200°) digital images in the macula in the Reykjavik eye study.

PubMed

Csutak, A; Lengyel, I; Jonasson, F; Leung, I; Geirsdottir, A; Xing, W; Peto, T

2010-10-01

To establish the agreement between image grading of conventional (45°) and ultra wide-angle (200°) digital images in the macula. In 2008, the 12-year follow-up was conducted on 573 participants of the Reykjavik Eye Study. This study included the use of the Optos P200C AF ultra wide-angle laser scanning ophthalmoscope alongside Zeiss FF 450 conventional digital fundus camera on 121 eyes with or without age-related macular degeneration using the International Classification System. Of these eyes, detailed grading was carried out on five cases each with hard drusen, geographic atrophy and chorioretinal neovascularisation, and six cases of soft drusen. Exact agreement and κ-statistics were calculated. Comparison of the conventional and ultra wide-angle images in the macula showed an overall 96.43% agreement (κ=0.93) with no disagreement at end-stage disease; although in one eye chorioretinal neovascularisation was graded as drusenoid pigment epithelial detachment. Of patients with drusen only, the exact agreement was 96.1%. The detailed grading showed no clinically significant disagreement between the conventional 45° and 200° images. On the basis of our results, there is a good agreement between grading conventional and ultra wide-angle images in the macula.

The Prevalence of Age-Related Eye Diseases and Visual Impairment in Aging: Current Estimates

PubMed Central

Klein, Ronald; Klein, Barbara E. K.

2013-01-01

Purpose. To examine prevalence of five age-related eye conditions (age-related cataract, AMD, open-angle glaucoma, diabetic retinopathy [DR], and visual impairment) in the United States. Methods. Review of published scientific articles and unpublished research findings. Results. Cataract, AMD, open-angle glaucoma, DR, and visual impairment prevalences are high in four different studies of these conditions, especially in people over 75 years of age. There are disparities among racial/ethnic groups with higher age-specific prevalence of DR, open-angle glaucoma, and visual impairment in Hispanics and blacks compared with whites, higher prevalence of age-related cataract in whites compared with blacks, and higher prevalence of late AMD in whites compared with Hispanics and blacks. The estimates are based on old data and do not reflect recent changes in the distribution of age and race/ethnicity in the United States population. There are no epidemiologic estimates of prevalence for many visually-impairing conditions. Conclusions. Ongoing prevalence surveys designed to provide reliable estimates of visual impairment, AMD, age-related cataract, open-angle glaucoma, and DR are needed. It is important to collect objective data on these and other conditions that affect vision and quality of life in order to plan for health care needs and identify areas for further research. PMID:24335069

Open-angle glaucoma in the Petit Basset Griffon Vendeen.

PubMed

Bedford, Peter G C

2017-03-01

To report the prevalence and clinical characteristics of an open-angle glaucoma in Petit Basset Griffon Vendeen (PBGV) dogs in the United Kingdom (UK). At breed society clinics extending over a 6-year period, 366 dogs of varying ages and both sexes were clinically examined for signs of glaucoma using slit-lamp biomicroscopy, indirect and direct ophthalmoscopy, tonometry, and gonioscopy. The prevalence of glaucoma was 10.4% (38 dogs). Clinical signs of the disease presented from 3 years of age onwards, the commonest initial feature being the elevation of intraocular pressure (IOP) in 15 dogs (39.4%). In addition to elevated IOP, another 13 dogs (34.2%) presented with other features of glaucoma, some with lens subluxation and globe enlargement and all with possible or known vision defects. In the remaining 10 dogs (26.3%), phacodonesis or lens subluxation was observed before subsequent elevation of IOP. High prevalence and similarity to the primary open-angle glaucoma (POAG) seen in the Beagle and Elkhound breeds indicate that an open-angle glaucoma is present in the PBGV in the UK and that this disease may be genetically determined in this breed. Although increased IOP is the commonest early diagnostic feature, lens instability prior to an increase in IOP may be part of the clinical picture. © 2016 American College of Veterinary Ophthalmologists.

Long Term Results of Visual Field Progression Analysis in Open Angle Glaucoma Patients Under Treatment.

PubMed

Kocatürk, Tolga; Bekmez, Sinan; Katrancı, Merve; Çakmak, Harun; Dayanır, Volkan

2015-01-01

To evaluate visual field progression with trend and event analysis in open angle glaucoma patients under treatment. Fifteen year follow-up results of 408 eyes of 217 glaucoma patients who were followed at Adnan Menderes University, Department of Ophthalmology between 1998 and 2013 were analyzed retrospectively. Visual field data were collected for Mean Deviation (MD), Visual Field Index (VFI), and event occurrence. There were 146 primary open-angle glaucoma (POAG), 123 pseudoexfoliative glaucoma (XFG) and 139 normal tension glaucoma (NTG) eyes. MD showed significant change in all diagnostic groups (p<0.001). The difference of VFI between first and last examinations were significantly different in POAG (p<0.001), and XFG (p<0.003) but not in NTG. VFI progression rates were -0.3, -0.43, and -0.2 % loss/year in treated POAG, XFG, and NTG, respectively. The number of empty triangles were statistically different between POAG-NTG (p=0.001), and XFG-NTG (p=0.002) groups. The number of half-filled (p=0.002), and full-filled (p=0.010) triangles were significantly different between XFG-NTG groups. Functional long-term follow-up of glaucoma patients can be monitored with visual field indices. We herein report our fifteen year follow-up results in open angle glaucoma.

Economic impact of primary open-angle glaucoma in Australia.

PubMed

Dirani, Mohamed; Crowston, Jonathan G; Taylor, Penny S; Moore, Peter T; Rogers, Sophie; Pezzullo, M Lynne; Keeffe, Jill E; Taylor, Hugh R

2011-01-01

Glaucoma is the World's leading cause of irreversible blindness, and poses serious public health and economic concerns.   Review. Published randomized trials and population-based studies since 1985. We report the economic impact of primary open-angle glaucoma and model the effect of changes in detection rates and management strategies. The cost-effectiveness of different interventions to prevent vision loss from primary open-angle glaucoma was measured in terms of financial cost (Australian dollars) and disability-adjusted life years. The prevalence of glaucoma in Australia is expected to increase from 208 000 in 2005 to 379 000 in 2025 because of the aging population. Health system costs over the same time period are estimated to increase from $AU355 million to $AU784 million. Total costs (health system costs, indirect costs and costs of loss of well-being) will increase from $AU1.9 billion to $AU4.3 billion in Australia. Primary open-angle glaucoma poses a significant economic burden, which will increase substantially by 2025. This dynamic model provides a valuable tool for ongoing policy formulation and determining the economic impact of interventions to better prevent visual impairment and blindness from glaucoma. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.

Investigation of Blade Angle of an Open Cross-Flow Runner

NASA Astrophysics Data System (ADS)

Katayama, Yusuke; Iio, Shouichiro; Veerapun, Salisa; Uchiyama, Tomomi

2015-04-01

The aim of this study was to develop a nano-hydraulic turbine utilizing drop structure in irrigation channels or industrial waterways. This study was focused on an open-type cross-flow turbine without any attached equipment for cost reduction and easy maintenance. In this study, the authors used an artificial indoor waterfall as lab model. Test runner which is a simple structure of 20 circular arc-shaped blades sandwiched by two circular plates was used The optimum inlet blade angle and the relationship between the power performance and the flow rate approaching theoretically and experimentally were investigated. As a result, the optimum inlet blade angle due to the flow rate was changed. Additionally, allocation rate of power output in 1st stage and 2nd stage is changed by the blade inlet angle.

Differences in iris thickness among African Americans, Caucasian Americans, Hispanic Americans, Chinese Americans, and Filipino-Americans.

PubMed

Lee, Roland Y; Huang, Guofu; Porco, Travis C; Chen, Yi-Chun; He, Mingguang; Lin, Shan C

2013-12-01

To evaluate the capability of iris thickness parameters to explain the difference in primary angle-closure glaucoma prevalence among the different racial groups. In this prospective study, 436 patients with open and narrow angles that met inclusion criteria were consecutively recruited from the UCSF general ophthalmology and glaucoma clinics to receive anterior segment optical coherence tomography imaging under standardized dark conditions. Images from 11 patients were removed due to poor visibility of the scleral spurs and the remaining images were analyzed using the Zhongshan Angle Assessment Program to assess the following measurements for the nasal and temporal angle of the anterior chamber: iris thickness at 750 and 2000 μm from the scleral spurs and the maximum iris thickness at middle one third of the iris. Iris thickness parameters were compared among and within the following 5 different racial groups: African Americans, Caucasian Americans, Hispanic Americans, Chinese Americans, and Filipino-Americans. In comparing iris parameters among the open-angle racial groups, significant differences were found for nasal iris thickness at 750 and 2000 μm from the scleral spurs in which Chinese Americans displayed the highest mean value (P=0.01, P<0.0001). Among the narrow-angle racial groups, significant difference was found for nasal iris thickness at 2000 μm from the scleral in which Chinese Americans showed the highest mean value (P<0.0001). Significant difference was also found for temporal maximum iris thickness at middle one third of the iris in which African Americans exhibited the highest mean value (P=0.021). Iris thickness was modeled as a function of angle status using linear mixed-effects regression, adjusting for age, sex, pupil diameter, spherical equivalent, ethnicity, and the use of both eyes in patients. The iris thickness difference between the narrow-angle and open-angle groups was significant (P=0.0007). Racial groups that historically showed higher prevalence of primary angle-closure glaucoma possess thicker irides.

Pilot Study of the Effects of Ambient Light Level Variation on Spectral Domain Anterior Segment OCT-Derived Angle Metrics in Caucasians versus Asians.

PubMed

Dastiridou, Anna; Marion, Kenneth; Niemeyer, Moritz; Francis, Brian; Sadda, Srinivas; Chopra, Vikas

2018-04-11

To investigate the effects of ambient light level variation on spectral domain anterior segment optical coherence tomography (SD-ΟCT)-derived anterior chamber angle metrics in Caucasians versus Asians. Caucasian (n = 24) and Asian participants of Chinese ancestry (n = 24) with open angles on gonioscopy had one eye imaged twice at five strictly controlled, ambient light levels. Ethnicity was self-reported. Light levels were strictly controlled using a light meter at 1.0, 0.75, 0.5, 0.25, and 0 foot candle illumination levels. SD-OCT 5-line raster scans at the inferior 270° irido-corneal angle were measured by two trained, masked graders from the Doheny Image Reading Center using customized Image-J software. Schwalbe's line-angle opening distance (SL-AOD) and SL-trabecular iris space area (SL-TISA) in different light meter readings (LMRs) between the two groups were compared. Baseline light SL-AOD and SL-TISA measured 0.464 ± 0.115mm/0.351 ± 0.110mm 2 and 0.344 ± 0.118mm/0.257 ± 0.092mm 2 , respectively, in the Caucasian and the Asian group. SL-AOD and SL-TISA in each LMR were significantly larger in the Caucasian group compared to the Asian group (p < 0.05). Despite this difference in angle size between the groups, there were no statistically significant differences in the degree of change in angle parameters from light to dark (% changes in SL-AOD or SL-TISA between the two groups were statistically similar with all p-values >0.3). SL-based angle dimensions using SD-OCT are sensitive to changes in ambient illumination in participants with Caucasian and Asian ancestry. Although Caucasian eyes had larger baseline angle opening under bright light conditions, the light-to-dark change in angle dimensions was similar in the two groups.

Novel Automated Approach to Predict the Outcome of Laser Peripheral Iridotomy for Primary Angle Closure Suspect Eyes Using Anterior Segment Optical Coherence Tomography.

PubMed

Koh, Victor; Swamidoss, Issac Niwas; Aquino, Maria Cecilia D; Chew, Paul T; Sng, Chelvin

2018-04-27

Develop an algorithm to predict the success of laser peripheral iridotomy (LPI) in primary angle closure suspect (PACS), using pre-treatment anterior segment optical coherence tomography (ASOCT) scans. A total of 116 eyes with PACS underwent LPI and time-domain ASOCT scans (temporal and nasal cuts) were performed before and 1 month after LPI. All the post-treatment scans were classified to one of the following categories: (a) both angles open, (b) one of two angles open and (c) both angles closed. After LPI, success is defined as one or more angles changed from close to open. In this proposed method, the pre and post-LPI ASOCT scans were registered at the corresponding angles based on similarities between the respective local descriptor features and random sample consensus technique was used to identify the largest consensus set of correspondences between the pre and post-LPI ASOCT scans. Subsequently, features such as correlation co-efficient (CC) and structural similarity index (SSIM) were extracted and correlated with the success of LPI. We included 116 eyes and 91 (78.44%) eyes fulfilled the criteria for success after LPI. Using the CC and SSIM index scores from this training set of ASOCT images, our algorithm showed that the success of LPI in eyes with narrow angles can be predicted with 89.7% accuracy, specificity of 95.2% and sensitivity of 36.4% based on pre-LPI ASOCT scans only. Using pre-LPI ASOCT scans, our proposed algorithm showed good accuracy in predicting the success of LPI for PACS eyes. This fully-automated algorithm could aid decision making in offering LPI as a prophylactic treatment for PACS.

Wide Angle of Incidence-Insensitive Polarization-Independent THz Metamaterial Absorber for Both TE and TM Mode Based on Plasmon Hybridizations.

PubMed

Huang, Xiu Tao; Lu, Cong Hui; Rong, Can Can; Wang, Sheng Ming; Liu, Ming Hai

2018-04-25

An ultra-wide-angle THz metamaterial absorber (MA) utilizing sixteen-circular-sector (SCR) resonator for both transverse electric (TE) and transverse magnetic (TM) mode is designed and investigated numerically. At normal incidence, the absorptivity of the proposed MA is higher than 93.7% at 9.05 THz for different polarization angles, due to the rotational symmetry structure of the unit cell. Under oblique incidence, the absorptivity can still exceed 90%, even when the incident angle is up to 70° for both TE and TM mode. Especially, the frequency variation in TE mode is less than 0.25% for different incident angles from 0° to 70°. The electric field (E z ) distributions are used to explain the absorption mechanism. Numerical simulation results show that the high absorption with wide-angle independence stems from fundamental dipole resonance and gap surface plasmons. The broadband deep-infrared MA is also obtained by stacking three metal-dielectric layers. The designed MA has great potential in bolometric pixel elements, biomedical sensors, THz imaging, and solar cells.

Passive rejection of heat from an isotope heat source through an open door

NASA Technical Reports Server (NTRS)

Burns, R. K.

1971-01-01

The isotope heat-source design for a Brayton power system includes a door in the thermal insulation through which the heat can be passively rejected to space when the power system is not operating. The results of an analysis to predict the heat-source surface temperature and the heat-source heat-exchanger temperature during passive heat rejection as a function of insulation door opening angle are presented. They show that for a door opening angle greater than 20 deg, the temperatures are less than the steady-state temperatures during power system operation.

[Basic and clinical studies of pressure-independent damaging factors of open angle glaucoma].

PubMed

Araie, Makoto

2011-03-01

Pathogenesis of open-angle glaucoma involves both pressure-dependent damaging factors and pressure-independent damaging factors. The high prevalence of open-angle glaucoma with normal pressure (normal-tension glaucoma) in Japan implies that treatment of pressure-independent damaging factors in Japanese open-angle glaucoma patients is of importance. In an attempt to investigate the roles of pressure-independent damaging factors in open-angle glaucoma, we carried out basic and clinical studies and obtained the following results. 1. The rate of deterioration of visual field after trabeculectomy in normal tension glaucoma patients with post-operative intraocular pressure (IOP) of 10 mmHg was found to be -0.25 dB/year of mean deviation (MD), suggesting that contribution of pressure-independent damaging factors to the deterioration of MD in open-angle glaucoma is around -0.25 dB/year of mean deviation (MD). 2. Experiments using isolated purified cultured retinal ganglion cells (RGCs) indicated that calcium-channel blockers and some of antiglaucoma drugs showed neuroprotective effects on RGCs at concentrations of 0.01 microM or higher. 3. In mice, damage to RGCs resulted in secondary degeneration of neurons and activation of glial cells in the lateral geniculate nucleous (LGN) and superior colliculus, and these secondary changes in the central nervous system (CNS) due to RGC damage was partly ameliorated by systemic administration of memantine. 4. Mice experimental high IOP glaucoma models could be established using laser irradiation of the limbal area, and the usefulness of Tonolab in IOP measurements of mice eye was confirmed. 5. Monkey experimental high IOP glaucoma models revealed that in the glaucomatous optic nerve head vaso-constrictive reactions to an alpha-1 agonist was abolished, while vasodilative reaction to a prostaglandin FP receptor agonist was retained. 6. In monkeys with experimental high IOP glaucoma, secondary damage to neurons in the LGN and the glial reaction to it were also found, similar to the mice experiments. In living monkeys the glial reaction in the LGN could be observed by means of positron emission tomography. 7. In the LGN of monkeys with experimental high IOP glaucoma, the M-cell system was preferentially damaged in the early stage, while in the later stages both the M- and P-cell systems were damaged. 8. In a single-instituted prospective double-blinded clinical trial, oral administration of nilvadipine at 4 mg/day, a DHP calcium-channel blocker, was found to significantly retard the visual field progression in normal tension glaucoma patients over 3 years, while significantly increasing the choroidal and optic nerve blood flow by about 35%. 9. A multi-instituted prospective double-blinded clinical trial in normal tension glaucoma patients revealed that the rate of MD deterioration under monotherapy with either topical nipradilol or timolol was around -0.05 dB/year, thought to be considerably slower than -0.25 dB/year, the commonly estimated rate of MD deterioration by pressure-independent damaging factors. The current results indicate the possibility of treatment of pressure-independent damaging factors of open-angle glaucoma in Japanese open-angle glaucoma patients with oral nilvadipine and topical anti-glaucoma agents.

Numerical study on the combustion characteristics of a fuel-centered pintle injector for methane rocket engines

NASA Astrophysics Data System (ADS)

Son, Min; Radhakrishnan, Kanmaniraja; Yoon, Youngbin; Koo, Jaye

2017-06-01

A pintle injector is a movable injector capable of controlling injection area and velocities. Although pintle injectors are not a new concept, they have become more notable due to new applications such as planet landers and low-cost engines. However, there has been little consistent research on pintle injectors because they have many design variations and mechanisms. In particular, simulation studies are required for bipropellant applications. In this study, combustion simulation was conducted using methane and oxygen to determine the effects of injection condition and geometries upon combustion characteristics. Steady and two-dimensional axisymmetric conditions were assumed and a 6-step Jones-Lindstedt mechanism with an eddy-dissipation concept model was used for turbulent kinetic reaction. As a result, the results with wide flame angles showed good combustion performances with a large recirculation under the pintle tip. Under lower mass flow-rate conditions, the combustion performance got worse with lower flame angles. To solve this problem, decreasing the pintle opening distance was very effective and the flame angle recovered. In addition, a specific recirculation zone was observed near the post, suggesting that proper design of the post could increase the combustion performance, while the geometry without a recirculation zone had the poor performance.

Underwound DNA under Tension: Structure, Elasticity, and Sequence-Dependent Behaviors

NASA Astrophysics Data System (ADS)

Sheinin, Maxim Y.; Forth, Scott; Marko, John F.; Wang, Michelle D.

2011-09-01

DNA melting under torsion plays an important role in a wide variety of cellular processes. In the present Letter, we have investigated DNA melting at the single-molecule level using an angular optical trap. By directly measuring force, extension, torque, and angle of DNA, we determined the structural and elastic parameters of torsionally melted DNA. Our data reveal that under moderate forces, the melted DNA assumes a left-handed structure as opposed to an open bubble conformation and is highly torsionally compliant. We have also discovered that at low forces melted DNA properties are highly dependent on DNA sequence. These results provide a more comprehensive picture of the global DNA force-torque phase diagram.

Wide-Angle, Flat-Field Telescope

NASA Technical Reports Server (NTRS)

Hallam, K. L.; Howell, B. J.; Wilson, M. E.

1987-01-01

All-reflective system unvignetted. Wide-angle telescope uses unobstructed reflecting elements to produce flat image. No refracting elements, no chromatic aberration, and telescope operates over spectral range from infrared to far ultraviolet. Telescope used with such image detectors as photographic firm, vidicons, and solid-state image arrays.

Observational Implications of Gamma-Ray Burst Afterglow Jet Simulations and Numerical Light Curve Calculations

NASA Astrophysics Data System (ADS)

van Eerten, Hendrik J.; MacFadyen, Andrew I.

2012-06-01

We discuss jet dynamics for narrow and wide gamma-ray burst (GRB) afterglow jets and the observational implications of numerical simulations of relativistic jets in two dimensions. We confirm earlier numerical results that sideways expansion of relativistic jets during the bulk of the afterglow emission phase is logarithmic in time and find that this also applies to narrow jets with half opening angle of 0.05 rad. As a result, afterglow jets remain highly nonspherical until after they have become nonrelativistic. Although sideways expansion steepens the afterglow light curve after the jet break, the jet edges becoming visible dominates the jet break, which means that the jet break is sensitive to the observer angle even for narrow jets. Failure to take the observer angle into account can lead to an overestimation of the jet energy by up to a factor of four. This weakens the challenge posed to the magneter energy limit by extreme events such as GRB090926A. Late-time radio calorimetry based on a spherical nonrelativistic outflow model remains relevant when the observer is approximately on-axis and where differences of a few in flux level between the model and the simulation are acceptable. However, this does not imply sphericity of the outflow and therefore does not translate to high observer angles relevant to orphan afterglows. For more accurate calorimetry and in order to model significant late-time features such as the rise of the counterjet, detailed jet simulations remain indispensable.

An Energetic Electron Flux Dropout Due to Magnetopause Shadowing on 1 June 2013

NASA Astrophysics Data System (ADS)

Kang, Suk-Bin; Fok, Mei-Ching; Komar, Colin; Glocer, Alex; Li, Wen; Buzulukova, Natalia

2018-02-01

We examine the mechanisms responsible for the dropout of energetic electron flux during 31 May to 1 June 2013 using Van Allen Probe (Radiation Belt Storm Probes (RBSP)) electron flux data and simulations with the Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. During the storm main phase, L-shells at RBSP locations are greater than 8, which are connected to open drift shells. Consequently, diminished electron fluxes were observed over a wide range of energies. The combination of drift shell splitting, magnetopause shadowing, and drift loss all results in butterfly electron pitch angle distributions (PADs) at the nightside. During storm sudden commencement, RBSP observations display electron butterfly PADs over a wide range of energies. However, it is difficult to determine whether there are butterfly PADs during the storm main phase since the maximum observable equatorial pitch angle from RBSP is not larger than 40° during this period. To investigate the causes of the dropout, the CIMI model is used as a global 4-D kinetic inner magnetosphere model. The CIMI model reproduces the dropout with very similar timing and flux levels and PADs along the RBSP trajectory for 593 keV. Furthermore, the CIMI simulation shows butterfly PADs for 593 keV during the storm main phase. Based on comparison of observations and simulations, we suggest that the dropout during this event mainly results from magnetopause shadowing.

A common variant mapping to CACNA1A is associated with susceptibility to Exfoliation syndrome

PubMed Central

Aung, Tin; Ozaki, Mineo; Mizoguchi, Takanori; Allingham, R Rand; Li, Zheng; Haripriya, Aravind; Nakano, Satoko; Uebe, Steffen; Harder, Jeffrey M.; Chan, Anita S.Y.; Lee, Mei Chin; Burdon, Kathryn P.; Astakhov, Yury S.; Abu-Amero, Khaled K.; Zenteno, Juan C.; Nilgün, Yildirim; Zarnowski, Tomasz; Pakravan, Mohammad; Safieh, Leen Abu; Jia, Liyun; Wang, Ya Xing; Williams, Susan; Paoli, Daniela; Schlottmann, Patricio G; Huang, Lulin; Sim, Kar Seng; Foo, Jia Nee; Nakano, Masakazu; Ikeda, Yoko; Kumar, Rajesh S; Ueno, Morio; Manabe, Shin-ichi; Hayashi, Ken; Kazama, Shigeyasu; Ideta, Ryuichi; Mori, Yosai; Miyata, Kazunori; Sugiyama, Kazuhisa; Higashide, Tomomi; Chihara, Etsuo; Inoue, Kenji; Ishiko, Satoshi; Yoshida, Akitoshi; Yanagi, Masahide; Kiuchi, Yoshiaki; Aihara, Makoto; Ohashi, Tsutomu; Sakurai, Toshiya; Sugimoto, Takako; Chuman, Hideki; Matsuda, Fumihiko; Yamashiro, Kenji; Gotoh, Norimoto; Miyake, Masahiro; Astakhov, Sergei Y.; Osman, Essam A.; Al-Obeidan, Saleh A.; Owaidhah, Ohoud; Al-Jasim, Leyla; Al Shahwan, Sami; Fogarty, Rhys A.; Leo, Paul; Yetkin, Yaz; Oğuz, Çilingir; Kanavi, Mozhgan Rezaei; Beni, Afsaneh Naderi; Yazdani, Shahin; Akopov, Evgeny L.; Toh, Kai-Yee; Howell, Gareth R; Orr, Andrew C.; Goh, Yufen; Meah, Wee Yang; Peh, Su Qin; Kosior-Jarecka, Ewa; Lukasik, Urszula; Krumbiegel, Mandy; Vithana, Eranga N; Wong, Tien Yin; Liu, Yutao; Ashley Koch, Allison E.; Challa, Pratap; Rautenbach, Robyn M; Mackey, David A.; Hewitt, Alex W; Mitchell, Paul; Wang, Jie Jin; Ziskind, Ari; Carmichael, Trevor; Ramakrishnan, Rangappa; Narendran, Kalpana; Venkatesh, Rangaraj; Vijayan, Saravanan; Zhao, Peiquan; Chen, Xueyi; Guadarrama-Vallejo, Dalia; Cheng, Ching Yu; Perera, Shamira A; Husain, Rahat; Ho, Su-Ling; Welge-Luessen, Ulrich-Christoph; Mardin, Christian; Schloetzer-Schrehardt, Ursula; Hillmer, Axel M.; Herms, Stefan; Moebus, Susanne; Nöthen, Markus M.; Weisschuh, Nicole; Shetty, Rohit; Ghosh, Arkasubhra; Teo, Yik Ying; Brown, Matthew A; Lischinsky, Ignacio; Crowston, Jonathan G; Coote, Michael; Zhao, Bowen; Sang, Jinghong; Zhang, Nihong; You, Qisheng; Vysochinskaya, Vera; Founti, Panayiota; Chatzikyriakidou, Anthoula; Lambropoulos, Alexandros; Anastasopoulos, Eleftherios; Coleman, Anne L; Wilson, M Roy; Rhee, Douglas J; Kang, Jae Hee; May-Bolchakova, Inna; Heegaard, Steffen; Mori, Kazuhiko; Alward, Wallace L.M.; Jonas, Jost B; Xu, Liang; Liebmann, Jeffrey M; Chowbay, Balram; Schaeffeler, Elke; Schwab, Matthias; Lerner, Fabian; Wang, Ningli; Yang, Zhenglin; Frezzotti, Paolo; Kinoshita, Shigeru; Fingert, John H.; Inatani, Masaru; Tashiro, Kei; Reis, André; Edward, Deepak P.; Pasquale, Louis R.; Kubota, Toshiaki; Wiggs, Janey L.; Pasutto, Francesca; Topouzis, Fotis; Dubina, Michael; Craig, Jamie E.; Yoshimura, Nagahisa; Sundaresan, Periasamy; John, Simon W.M.; Ritch, Robert; Hauser, Michael A; Khor, Chiea-Chuen

2015-01-01

Exfoliation syndrome (XFS) is the commonest recognizable cause of open angle glaucoma world-wide. To better understand the etiology of XFS, we conducted a genome-wide association study (GWAS) on 1,484 patients and 1,188 controls from Japan, and followed up the most significant findings on a further 6,901 patients and 20,727 controls from 17 countries across 6 continents. We discovered a significant association between a new locus (CACNA1A rs4926244) and increased susceptibility to XFS (Odds ratio [OR] = 1.16, P = 3.36 × 10−11). Although overwhelming association at the LOXL1 locus was confirmed, the key SNP marker (LOXL1 rs4886776) demonstrated allelic reversal depending on ethnic grouping (In Japanese: ORA-allele= 9.87, P = 2.13 × 10−217; In non-Japanese: ORA-allele= 0.49, P = 2.35 × 10−31). Our findings represent the first genetic locus outside of LOXL1 which surpasses genome-wide significance for XFS, and provides insight into the biology and pathogenesis of the disease. PMID:25706626

A common variant mapping to CACNA1A is associated with susceptibility to exfoliation syndrome.

PubMed

Aung, Tin; Ozaki, Mineo; Mizoguchi, Takanori; Allingham, R Rand; Li, Zheng; Haripriya, Aravind; Nakano, Satoko; Uebe, Steffen; Harder, Jeffrey M; Chan, Anita S Y; Lee, Mei Chin; Burdon, Kathryn P; Astakhov, Yury S; Abu-Amero, Khaled K; Zenteno, Juan C; Nilgün, Yildirim; Zarnowski, Tomasz; Pakravan, Mohammad; Safieh, Leen Abu; Jia, Liyun; Wang, Ya Xing; Williams, Susan; Paoli, Daniela; Schlottmann, Patricio G; Huang, Lulin; Sim, Kar Seng; Foo, Jia Nee; Nakano, Masakazu; Ikeda, Yoko; Kumar, Rajesh S; Ueno, Morio; Manabe, Shin-ichi; Hayashi, Ken; Kazama, Shigeyasu; Ideta, Ryuichi; Mori, Yosai; Miyata, Kazunori; Sugiyama, Kazuhisa; Higashide, Tomomi; Chihara, Etsuo; Inoue, Kenji; Ishiko, Satoshi; Yoshida, Akitoshi; Yanagi, Masahide; Kiuchi, Yoshiaki; Aihara, Makoto; Ohashi, Tsutomu; Sakurai, Toshiya; Sugimoto, Takako; Chuman, Hideki; Matsuda, Fumihiko; Yamashiro, Kenji; Gotoh, Norimoto; Miyake, Masahiro; Astakhov, Sergei Y; Osman, Essam A; Al-Obeidan, Saleh A; Owaidhah, Ohoud; Al-Jasim, Leyla; Al Shahwan, Sami; Fogarty, Rhys A; Leo, Paul; Yetkin, Yaz; Oğuz, Çilingir; Kanavi, Mozhgan Rezaei; Beni, Afsaneh Nederi; Yazdani, Shahin; Akopov, Evgeny L; Toh, Kai-Yee; Howell, Gareth R; Orr, Andrew C; Goh, Yufen; Meah, Wee Yang; Peh, Su Qin; Kosior-Jarecka, Ewa; Lukasik, Urszula; Krumbiegel, Mandy; Vithana, Eranga N; Wong, Tien Yin; Liu, Yutao; Koch, Allison E Ashley; Challa, Pratap; Rautenbach, Robyn M; Mackey, David A; Hewitt, Alex W; Mitchell, Paul; Wang, Jie Jin; Ziskind, Ari; Carmichael, Trevor; Ramakrishnan, Rangappa; Narendran, Kalpana; Venkatesh, Rangaraj; Vijayan, Saravanan; Zhao, Peiquan; Chen, Xueyi; Guadarrama-Vallejo, Dalia; Cheng, Ching Yu; Perera, Shamira A; Husain, Rahat; Ho, Su-Ling; Welge-Luessen, Ulrich-Christoph; Mardin, Christian; Schloetzer-Schrehardt, Ursula; Hillmer, Axel M; Herms, Stefan; Moebus, Susanne; Nöthen, Markus M; Weisschuh, Nicole; Shetty, Rohit; Ghosh, Arkasubhra; Teo, Yik Ying; Brown, Matthew A; Lischinsky, Ignacio; Crowston, Jonathan G; Coote, Michael; Zhao, Bowen; Sang, Jinghong; Zhang, Nihong; You, Qisheng; Vysochinskaya, Vera; Founti, Panayiota; Chatzikyriakidou, Anthoula; Lambropoulos, Alexandros; Anastasopoulos, Eleftherios; Coleman, Anne L; Wilson, M Roy; Rhee, Douglas J; Kang, Jae Hee; May-Bolchakova, Inna; Heegaard, Steffen; Mori, Kazuhiko; Alward, Wallace L M; Jonas, Jost B; Xu, Liang; Liebmann, Jeffrey M; Chowbay, Balram; Schaeffeler, Elke; Schwab, Matthias; Lerner, Fabian; Wang, Ningli; Yang, Zhenglin; Frezzotti, Paolo; Kinoshita, Shigeru; Fingert, John H; Inatani, Masaru; Tashiro, Kei; Reis, André; Edward, Deepak P; Pasquale, Louis R; Kubota, Toshiaki; Wiggs, Janey L; Pasutto, Francesca; Topouzis, Fotis; Dubina, Michael; Craig, Jamie E; Yoshimura, Nagahisa; Sundaresan, Periasamy; John, Simon W M; Ritch, Robert; Hauser, Michael A; Khor, Chiea-Chuen

2015-04-01

Exfoliation syndrome (XFS) is the most common recognizable cause of open-angle glaucoma worldwide. To better understand the etiology of XFS, we conducted a genome-wide association study (GWAS) of 1,484 cases and 1,188 controls from Japan and followed up the most significant findings in a further 6,901 cases and 20,727 controls from 17 countries across 6 continents. We discovered a genome-wide significant association between a new locus (CACNA1A rs4926244) and increased susceptibility to XFS (odds ratio (OR) = 1.16, P = 3.36 × 10(-11)). Although we also confirmed overwhelming association at the LOXL1 locus, the key SNP marker (LOXL1 rs4886776) demonstrated allelic reversal depending on the ancestry group (Japanese: OR(A allele) = 9.87, P = 2.13 × 10(-217); non-Japanese: OR(A allele) = 0.49, P = 2.35 × 10(-31)). Our findings represent the first genetic locus outside of LOXL1 surpassing genome-wide significance for XFS and provide insight into the biology and pathogenesis of the disease.

Linkage studies in primary open angle glaucoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avramopoulos, D.; Grigoriadu, M.; Kitsos, G.

1994-09-01

Glaucoma is a leading cause of blindness worldwide. The majority of glaucoma is associated with an open, normal appearing anterior chamber angle and is termed primary open angle glaucoma (POAG, MIM 137760). It is characterized by elevated intraocular pressure and onset in middle age or later. A subset of POAG with juvenile onset has recently been linked to chromosome 1q in two families with autosomal dominant inheritance. Eleven pedigrees with autosomal dominant POG (non-juvenile-onset) have been identified in Epirus, Greece. In the present study DNA samples have been collected from 50 individuals from one large pedigree, including 12 affected individuals.more » Preliminary results of linkage analysis with chromosome 1 microsatellites using the computer program package LINKAGE Version 5.1 showed no linkage with the markers previously linked to juvenile-onset POAG. Further linkage analysis is being pursued, and the results will be presented.« less

Visual Disability Among Juvenile Open-angle Glaucoma Patients.

PubMed

Gupta, Viney; Ganesan, Vaitheeswaran L; Kumar, Sandip; Chaurasia, Abadh K; Malhotra, Sumit; Gupta, Shikha

2018-04-01

Juvenile onset primary open-angle glaucoma (JOAG) unlike adult onset primary open-angle glaucoma presents with high intraocular pressure and diffuse visual field loss, which if left untreated leads to severe visual disability. The study aimed to evaluate the extent of visual disability among JOAG patients presenting to a tertiary eye care facility. Visual acuity and perimetry records of unrelated JOAG patients presenting to our Glaucoma facility were analyzed. Low vision and blindness was categorized by the WHO criteria and percentage impairment was calculated as per the guidelines provided by the American Medical Association (AMA). Fifty-two (15%) of the 348 JOAG patients were bilaterally blind at presentation and 32 (9%) had low vision according to WHO criteria. Ninety JOAG patients (26%) had a visual impairment of 75% or more. Visual disability at presentation among JOAG patients is high. This entails a huge economic burden, given their young age and associated social responsibilities.

Bayesian refinement of protein structures and ensembles against SAXS data using molecular dynamics

PubMed Central

Shevchuk, Roman; Hub, Jochen S.

2017-01-01

Small-angle X-ray scattering is an increasingly popular technique used to detect protein structures and ensembles in solution. However, the refinement of structures and ensembles against SAXS data is often ambiguous due to the low information content of SAXS data, unknown systematic errors, and unknown scattering contributions from the solvent. We offer a solution to such problems by combining Bayesian inference with all-atom molecular dynamics simulations and explicit-solvent SAXS calculations. The Bayesian formulation correctly weights the SAXS data versus prior physical knowledge, it quantifies the precision or ambiguity of fitted structures and ensembles, and it accounts for unknown systematic errors due to poor buffer matching. The method further provides a probabilistic criterion for identifying the number of states required to explain the SAXS data. The method is validated by refining ensembles of a periplasmic binding protein against calculated SAXS curves. Subsequently, we derive the solution ensembles of the eukaryotic chaperone heat shock protein 90 (Hsp90) against experimental SAXS data. We find that the SAXS data of the apo state of Hsp90 is compatible with a single wide-open conformation, whereas the SAXS data of Hsp90 bound to ATP or to an ATP-analogue strongly suggest heterogenous ensembles of a closed and a wide-open state. PMID:29045407

Data report for onshore-offshore wide-angle seismic recordings in the Bering-Chukchi Sea, Western Alaska and eastern Siberia

USGS Publications Warehouse

Brocher, Thomas M.; Allen, Richard M.; Stone, David B.; Wolf, Lorraine W.; Galloway, Brian K.

1995-01-01

This report presents fourteen deep-crustal wide-angle seismic reflection and refraction profiles recorded onland in western Alaska and eastern Siberia from marine air gun sources in the Bering-Chukchi Seas. During a 20-day period in August, 1994, the R/V Ewing acquired two long (a total of 3754 km) deep-crustal seismic-reflection profiles on the continental shelf of the Bering and Chukchi Seas, in a collaborative project between Stanford University and the United States Geological Survey (USGS). The Ewing's 137.7 liter (8355 cu. in.) air gun array was the source for both the multichannel reflection and the wide-angle seismic data. The Ewing, operated by the Lamont-Doherty Earth Observatory, steamed northward from Nunivak Island to Barrow, and returned, firing the air gun array at intervals of either 50 m or 75 m. About 37,700 air gun shots were fired along the northward directed Lines 1 and 2, and more than 40,000 air gun shots were fired along the southward directed Line 3. The USGS and the University of Alaska, Fairbanks (UAF), deployed an array of twelve 3-component REFTEK and PDAS recorders in western Alaska and eastern Siberia which continuously recorded the air gun signals fired during the northward bound Lines 1 and 2. Seven of these recorders also continuously recorded the southward bound Line 3. These wide-angle seismic data were acquired to: (1) image reflectors in the upper to lower crust, (2) determine crustal and upper mantle refraction velocities, and (3) provide important constraints on the geometry of the Moho along the seismic lines. In this report, we describe the land recording of wide-angle data conducted by the USGS and the UAF, describe in detail how the wide-angle REFTEK and PDAS data were reduced to common receiver gather seismic sections, and illustrate the wide-angle seismic data obtained by the REFTEKs and PDAS's. Air gun signals were observed to ranges in excess of 400 km, and crustal and upper /mantle refractions indicate substantial variation in the crustal thickness along the transect.

Optimal design of wide-view-angle waveplate used for polarimetric diagnosis of lithography system

NASA Astrophysics Data System (ADS)

Gu, Honggang; Jiang, Hao; Zhang, Chuanwei; Chen, Xiuguo; Liu, Shiyuan

2016-03-01

The diagnosis and control of the polarization aberrations is one of the main concerns in a hyper numerical aperture (NA) lithography system. Waveplates are basic and indispensable optical components in the polarimetric diagnosis tools for the immersion lithography system. The retardance of a birefringent waveplate is highly sensitive to the incident angle of the light, which makes the conventional waveplate not suitable to be applied in the polarimetric diagnosis for the immersion lithography system with a hyper NA. In this paper, we propose a method for the optimal design of a wideview- angle waveplate by combining two positive waveplates made from magnesium fluoride (MgF2) and two negative waveplates made from sapphire using the simulated annealing algorithm. Theoretical derivations and numerical simulations are performed and the results demonstrate that the maximum variation in the retardance of the optimally designed wide-view-angle waveplate is less than +/- 0.35° for a wide-view-angle range of +/- 20°.

Beyond the plane-parallel and Newtonian approach: wide-angle redshift distortions and convergence in general relativity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bertacca, Daniele; Maartens, Roy; Raccanelli, Alvise

We extend previous analyses of wide-angle correlations in the galaxy power spectrum in redshift space to include all general relativistic effects. These general relativistic corrections to the standard approach become important on large scales and at high redshifts, and they lead to new terms in the wide-angle correlations. We show that in principle the new terms can produce corrections of nearly 10% on Gpc scales over the usual Newtonian approximation. General relativistic corrections will be important for future large-volume surveys such as SKA and Euclid, although the problem of cosmic variance will present a challenge in observing this.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, B; Wong, R; Lam, W

Purpose: To develop a practical method for routine QA of the MLC of a Tomotherapy unit using ArcCheck. Methods: Two standard test plans were used in this study. One was a helical test, in which the central leaves No. 32 and 33 opened simultaneously for 277.8ms at projections centered at 0°, 120° and 240° gantry angles. The other test plan was a static test with the gantry angle set at 0°, 45°, 90° and 135° respectively and leaves No. 32 and 33 opened sequentially for total 20s which was further divided into eleven or ten segments at each beam angle.more » The ArcCheck was isocentrically set up and adjusted for couch sag. Movie files which took a snapshot exposure every 50ms were recorded. The start/stop time of leaf open was decided by the ramp-up/ramp-down of the detectors. Results: The percentage differences between measured and planned leaf open time were calculated to be within 0.5% in all the tests. In static test, if leaves are synchronized perfectly, the sum of the two detectors’ signals after normalization should equal one when the leaves are in transition. Our results showed mean values of 0.982, 0.983, 0.978 and 0.995 at static gantry angle 0°, 45°, 90° and 135° respectively. Conclusion: A method for estimating the Tomotherapy binary MLC leaf open time using ArcCheck is proposed and proved to be precise enough to verify the planned leaf open time as small as 277.8ms. This method also makes the observation and quantification of the synchronization of leaves possible.« less

Noctilucent cloud polarimetry: Twilight measurements in a wide range of scattering angles

NASA Astrophysics Data System (ADS)

Ugolnikov, Oleg S.; Maslov, Igor A.; Kozelov, Boris V.; Dlugach, Janna M.

2016-06-01

Wide-field polarization measurements of the twilight sky background during several nights with bright and extended noctilucent clouds in central and northern Russia in 2014 and 2015 are used to build the phase dependence of the degree of polarization of sunlight scattered by cloud particles in a wide range of scattering angles (from 40° to 130°). This range covers the linear polarization maximum near 90° and large-angle slope of the curve. The polarization in this angle range is most sensitive to the particle size. The method of separation of scattering on cloud particles from the twilight background is presented. Results are compared with T-matrix simulations for different sizes and shapes of ice particles; the best-fit model radius of particles (0.06 μm) and maximum radius (about 0.1 μm) are estimated.

Wide-angle, polarization-insensitive and broadband absorber based on eight-fold symmetric SRRs metamaterial

NASA Astrophysics Data System (ADS)

Wu, Dong; Liu, Yumin; Yu, Zhongyuan; Chen, Lei; Ma, Rui; Li, Yutong; Li, Ruifang; Ye, Han

2016-12-01

In this paper, we propose a novel three dimensional metamaterial design with eight-fold rotational symmetry that shows a polarization-insensitive, wide-angle and broadband perfect absorption in the microwave band. By simulation, the polarization-insensitive absorption is over 90% between 26.9 GHz to 32.9 GHz, and the broadband absorption remains a good absorption performance to a wide incident angles for both TE and TM polarizations. The magnetic field distribution are investigated to interpret the physical mechanism of broadband absorption. The broadband absorption is based on overlapping the multiple magnetic resonances at the neighboring frequencies by coupling effects of multiple metallic split-ring resonators (SRRs). Moreover, it is demonstrate that the designed structure can be extended to other frequencies by scale down the size of the unit cell, such as the visible frequencies. The simulated results show that the absorption of the smaller absorber is above 90% in the frequency range from 467 THz to 765 THz(392-642 nm), which include orange to purple light in visible region(400-760nm). The wide-angle and polarization-insensitive stabilities of the smaller absorber is also demonstrated at visible region. The proposed work provides a new design of realization of a polarization-insensitive, wide-angle and broadband absorber ranging different frequency bands, and such a structure has potential application in the fields of solar cell, imaging and detection.

Experimental assessment of theory for refraction of sound by a shear layer

NASA Technical Reports Server (NTRS)

Schlinker, R. H.; Amiet, R. K.

1978-01-01

The refraction angle and amplitude changes associated with sound transmission through a circular, open-jet shear layer were studied in a 0.91 m diameter open jet acoustic research tunnel. Free stream Mach number was varied from 0.1 to 0.4. Good agreement between refraction angle correction theory and experiment was obtained over the test Mach number, frequency and angle measurement range for all on-axis acoustic source locations. For off-axis source positions, good agreement was obtained at a source-to-shear layer separation distance greater than the jet radius. Measureable differences between theory and experiment occurred at a source-to-shear layer separation distance less than one jet radius. A shear layer turbulence scattering experiment was conducted at 90 deg to the open jet axis for the same free stream Mach numbers and axial source locations used in the refraction study. Significant discrete tone spectrum broadening and tone amplitude changes were observed at open jet Mach numbers above 0.2 and at acoustic source frequencies greater than 5 kHz. More severe turbulence scattering was observed for downstream source locations.

Zero-stress states of human pulmonary arteries and veins.

PubMed

Huang, W; Yen, R T

1998-09-01

The zero-stress states of the pulmonary arteries and veins from order 3 to order 9 were determined in six normal human lungs within 15 h postmortem. The zero-stress state of each vessel was obtained by cutting the vessel transversely into a series of short rings, then cutting each ring radially, which caused the ring to spring open into a sector. Each sector was characterized by its opening angle. The mean opening angle varied between 92 and 163 degrees in the arterial tree and between 89 and 128 degrees in the venous tree. There was a tendency for opening angles to increase as the sizes of the arteries and veins increased. We computed the residual strains based on the experimental measurements and estimated the residual stresses according to Hooke's law. We found that the inner wall of a vessel at the state in which the internal pressure, external pressure, and longitudinal stress are all zero was under compression and the outer wall was in tension, and that the magnitude of compressive stress was greater than the magnitude of tensile stress.

Does hemipelvis structure and position influence acetabulum orientation?

PubMed

Musielak, Bartosz; Jóźwiak, Marek; Rychlik, Michał; Chen, Brian Po-Jung; Idzior, Maciej; Grzegorzewski, Andrzej

2016-03-16

Although acetabulum orientation is well established anatomically and radiographically, its relation to the innominate bone has rarely been addressed. If explored, it could open the discussion on patomechanisms of such complex disorders as femoroacetabular impingement (FAI). We therefore evaluated the influence of pelvic bone position and structure on acetabular spatial orientation. We describe this relation and its clinical implications. This retrospective study was based on computed tomography scanning of three-dimensional models of 31 consecutive male pelvises (62 acetabulums). All measurements were based on CT spatial reconstruction with the use of highly specialized software (Rhinoceros). Relations between acetabular orientation (inclination, tilt, anteversion angles) and pelvic structure were evaluated. The following parameters were evaluated to assess the pelvic structure: iliac opening angle, iliac tilt angle, interspinous distance (ISD), intertuberous distance (ITD), height of the pelvis (HP), and the ISD/ITD/HP ratio. The linear and nonlinear dependence of the acetabular angles and hemipelvic measurements were examined with Pearson's product - moment correlation and Spearman's rank correlation coefficient. Correlations different from 0 with p < 0.05 were considered statistically significant. Comparison of the axis position with pelvis structure with orientation in the horizontal plane revealed a significant positive correlation between the acetabular anteversion angle and the iliac opening angle (p = 0.041 and 0.008, respectively). In the frontal plane, there was a positive correlation between the acetabular inclination angle and the iliac tilt angle (p = 0.025 and 0.014, respectively) and the acetabular inclination angle and the ISD/ITD/HP ratio (both p = 0.048). There is a significant correlation of the hemipelvic structure and acetabular orientation under anatomic conditions, especially in the frontal and horizontal planes. In the anteroposterior view, the more tilted-down innominate bone causes a more caudally oriented acetabulum axis, whereas in the horizontal view this relation is reversed. This study may serve as a basis for the discussion on the role of the pelvis in common disorders of the hip.

Association of Baseline Anterior Segment Parameters With the Development of Incident Gonioscopic Angle Closure.

PubMed

Nongpiur, Monisha E; Aboobakar, Inas F; Baskaran, Mani; Narayanaswamy, Arun; Sakata, Lisandro M; Wu, Renyi; Atalay, Eray; Friedman, David S; Aung, Tin

2017-03-01

Baseline anterior segment imaging parameters associated with incident gonioscopic angle closure, to our knowledge, are unknown. To identify baseline quantitative anterior segment optical coherence tomography parameters associated with the development of incident gonioscopic angle closure after 4 years among participants with gonioscopically open angles at baseline. Three hundred forty-two participants aged 50 years or older were recruited to participate in this prospective, community-based observational study. Participants underwent gonioscopy and anterior segment optical coherence tomography imaging at baseline and after 4 years. Custom image analysis software was used to quantify anterior chamber parameters from anterior segment optical coherence tomography images. Baseline anterior segment optical coherence tomography measurements among participants with gonioscopically open vs closed angles at follow-up. Of the 342 participants, 187 (55%) were women and 297 (87%) were Chinese. The response rate was 62.4%. Forty-nine participants (14.3%) developed gonioscopic angle closure after 4 years. The mean age (SD) at baseline of the 49 participants was 62.9 (8.0) years, 15 (30.6%) were men, and 43 (87.8%) were Chinese. These participants had a smaller baseline angle opening distance at 750 µm (AOD750) (0.15 mm; 95% CI, 0.12-0.18), trabecular iris surface area at 750 µm (0.07 mm2; 95% CI, 0.05-0.08), anterior chamber area (30 mm2; 95% CI, 2.27-3.74), and anterior chamber volume (24.32 mm2; 95% CI, 18.20-30.44) (all P < .001). Baseline iris curvature (-0.08; 95% CI, -0.12 to -0.04) and lens vault (LV) measurements (-0.29 mm; 95% CI, -0.37 to -0.21) were larger among these participants ( all P < .001). A model consisting of the LV and AOD750 measurements explained 38% of the variance in gonioscopic angle closure occurring at 4 years, with LV accounting for 28% of this variance. For every 0.1 mm increase in LV and 0.1 mm decrease in AOD750, the odds of developing gonioscopic angle closure was 1.29 (95% CI, 1.07-1.57) and 3.27 (95% CI, 1.87-5.69), respectively. In terms of per SD change in LV and AOD750, this translates to an odds ratio of 2.14 (95% CI, 2.48-12.34) and 5.53 (95% CI, 1.22-3.77), respectively. A baseline LV cut-off value of >0.56 mm had 64.6% sensitivity and 84.0% specificity for identifying participants who developed angle closure. These findings suggest that smaller AOD750 and larger LV measurements are associated with the development of incident gonioscopic angle closure after 4 years among participants with gonioscopically open angles at baseline.

Evolution of the mean jet shape and dijet asymmetry distribution of an ensemble of holographic jets in strongly coupled plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brewer, Jasmine; Rajagopal, Krishna; Sadofyev, Andrey

Some of the most important experimentally accessible probes of the quark- gluon plasma (QGP) produced in heavy ion collisions come from the analysis of how the shape and energy of sprays of energetic particles produced within a cone with a specified opening angle (jets) in a hard scattering are modified by their passage through the strongly coupled, liquid, QGP. We model an ensemble of back-to-back dijets for the purpose of gaining a qualitative understanding of how the shapes of the individual jets and the asymmetry in the energy of the pairs of jets in the ensemble are modified by theirmore » passage through an expanding cooling droplet of strongly coupled plasma, in the model in a holographic gauge theory that is dual to a 4+1-dimensional black-hole spacetime that is asymptotically anti-de Sitter (AdS). We build our model by constructing an ensemble of strings in the dual gravitational description of the gauge theory. We model QCD jets in vacuum using strings whose endpoints are moving “downward” into the gravitational bulk spacetime with some fixed small angle, an angle that represents the opening angle (ratio of jet mass to jet energy) that the QCD jet would have in vacuum. Such strings must be moving through the gravitational bulk at (close to) the speed of light; they must be (close to) null. This condition does not specify the energy distribution along the string, meaning that it does not specify the shape of the jet being modeled. We study the dynamics of strings that are initially not null and show that strings with a wide range of initial conditions rapidly accelerate and become null and, as they do, develop a similar distribution of their energy density. We use this distribution of the energy density along the string, choose an ensemble of strings whose opening angles and energies are distributed as in perturbative QCD, and show that we can then fix one of the two model parameters such that the mean jet shape for the jets in the ensemble that we have built matches that measured in proton-proton collisions reasonably well. This is a novel way for hybridizing relevant inputs from perturbative QCD and a strongly coupled holographic gauge theory in the service of modeling jets in QGP. We send our ensemble of strings through an expanding cooling droplet of strongly coupled plasma, choosing the second model parameter so as to get a reasonable value for R AA jet , the suppression in the number of jets, and study how the mean jet shape and the dijet asymmetry are modified, comparing both to measurements from heavy ion collisions at the LHC.« less

Evolution of the mean jet shape and dijet asymmetry distribution of an ensemble of holographic jets in strongly coupled plasma

DOE PAGES

Brewer, Jasmine; Rajagopal, Krishna; Sadofyev, Andrey; ...

2018-02-02

Some of the most important experimentally accessible probes of the quark- gluon plasma (QGP) produced in heavy ion collisions come from the analysis of how the shape and energy of sprays of energetic particles produced within a cone with a specified opening angle (jets) in a hard scattering are modified by their passage through the strongly coupled, liquid, QGP. We model an ensemble of back-to-back dijets for the purpose of gaining a qualitative understanding of how the shapes of the individual jets and the asymmetry in the energy of the pairs of jets in the ensemble are modified by theirmore » passage through an expanding cooling droplet of strongly coupled plasma, in the model in a holographic gauge theory that is dual to a 4+1-dimensional black-hole spacetime that is asymptotically anti-de Sitter (AdS). We build our model by constructing an ensemble of strings in the dual gravitational description of the gauge theory. We model QCD jets in vacuum using strings whose endpoints are moving “downward” into the gravitational bulk spacetime with some fixed small angle, an angle that represents the opening angle (ratio of jet mass to jet energy) that the QCD jet would have in vacuum. Such strings must be moving through the gravitational bulk at (close to) the speed of light; they must be (close to) null. This condition does not specify the energy distribution along the string, meaning that it does not specify the shape of the jet being modeled. We study the dynamics of strings that are initially not null and show that strings with a wide range of initial conditions rapidly accelerate and become null and, as they do, develop a similar distribution of their energy density. We use this distribution of the energy density along the string, choose an ensemble of strings whose opening angles and energies are distributed as in perturbative QCD, and show that we can then fix one of the two model parameters such that the mean jet shape for the jets in the ensemble that we have built matches that measured in proton-proton collisions reasonably well. This is a novel way for hybridizing relevant inputs from perturbative QCD and a strongly coupled holographic gauge theory in the service of modeling jets in QGP. We send our ensemble of strings through an expanding cooling droplet of strongly coupled plasma, choosing the second model parameter so as to get a reasonable value for R AA jet , the suppression in the number of jets, and study how the mean jet shape and the dijet asymmetry are modified, comparing both to measurements from heavy ion collisions at the LHC.« less

Evolution of the mean jet shape and dijet asymmetry distribution of an ensemble of holographic jets in strongly coupled plasma

NASA Astrophysics Data System (ADS)

Brewer, Jasmine; Rajagopal, Krishna; Sadofyev, Andrey; van der Schee, Wilke

2018-02-01

Some of the most important experimentally accessible probes of the quark- gluon plasma (QGP) produced in heavy ion collisions come from the analysis of how the shape and energy of sprays of energetic particles produced within a cone with a specified opening angle (jets) in a hard scattering are modified by their passage through the strongly coupled, liquid, QGP. We model an ensemble of back-to-back dijets for the purpose of gaining a qualitative understanding of how the shapes of the individual jets and the asymmetry in the energy of the pairs of jets in the ensemble are modified by their passage through an expanding cooling droplet of strongly coupled plasma, in the model in a holographic gauge theory that is dual to a 4+1-dimensional black-hole spacetime that is asymptotically anti-de Sitter (AdS). We build our model by constructing an ensemble of strings in the dual gravitational description of the gauge theory. We model QCD jets in vacuum using strings whose endpoints are moving "downward" into the gravitational bulk spacetime with some fixed small angle, an angle that represents the opening angle (ratio of jet mass to jet energy) that the QCD jet would have in vacuum. Such strings must be moving through the gravitational bulk at (close to) the speed of light; they must be (close to) null. This condition does not specify the energy distribution along the string, meaning that it does not specify the shape of the jet being modeled. We study the dynamics of strings that are initially not null and show that strings with a wide range of initial conditions rapidly accelerate and become null and, as they do, develop a similar distribution of their energy density. We use this distribution of the energy density along the string, choose an ensemble of strings whose opening angles and energies are distributed as in perturbative QCD, and show that we can then fix one of the two model parameters such that the mean jet shape for the jets in the ensemble that we have built matches that measured in proton-proton collisions reasonably well. This is a novel way for hybridizing relevant inputs from perturbative QCD and a strongly coupled holographic gauge theory in the service of modeling jets in QGP. We send our ensemble of strings through an expanding cooling droplet of strongly coupled plasma, choosing the second model parameter so as to get a reasonable value for R AA jet , the suppression in the number of jets, and study how the mean jet shape and the dijet asymmetry are modified, comparing both to measurements from heavy ion collisions at the LHC.

Comparison between wide-angle OCT angiography and ultra-wide field fluorescein angiography for detecting non-perfusion areas and retinal neovascularization in eyes with diabetic retinopathy.

PubMed

Sawada, Osamu; Ichiyama, Yusuke; Obata, Syunpei; Ito, Yuka; Kakinoki, Masashi; Sawada, Tomoko; Saishin, Yoshitsugu; Ohji, Masahito

2018-04-30

To compare the ability of wide-angle optical coherence tomography angiography (OCTA) with that of ultra-wide field fluorescein angiography (UWFFA) to detect non-perfusion areas (NPAs) or retinal neovascularization (NV) in eyes with diabetic retinopathy (DR). Patients with DR underwent UWFFA using the Optos® panoramic 200Tx imaging system and wide-angle OCTA with 12 × 12 mm fields of five visual fixations using the PLEX Elite 9000®. We compared the abilities of UWFFA and OCTA to detect NPAs and NV. Fifty-eight eyes of 33 patients (mean age, 60.0 years old; female/male, 16/17) with DR were evaluated. NPAs were detected in 47 out of 58 eyes using UWFFA and in 48 eyes using OCTA. NVs were detected in 25 out of the 58 eyes using UWFFA and in 26 eyes using OCTA. The sensitivity for detection of NPA using OCTA was 0.98, and the specificity was 0.82. The sensitivity for detection of NV was 1.0, and the specificity was 0.97. The wide-angle OCTA seems to be clinically useful for the detection of NPAs or NV.

Integration of least angle regression with empirical Bayes for multi-locus genome-wide association studies

USDA-ARS?s Scientific Manuscript database

Multi-locus genome-wide association studies has become the state-of-the-art procedure to identify quantitative trait loci (QTL) associated with traits simultaneously. However, implementation of multi-locus model is still difficult. In this study, we integrated least angle regression with empirical B...

Wide angle view of the Flight control room of Mission control center

NASA Image and Video Library

1984-10-06

Wide angle view of the flight control room (FCR) of the Mission Control Center (MCC). Some of the STS 41-G crew can be seen on a large screen at the front of the MCC along with a map tracking the progress of the orbiter.

Refractory open-angle glaucoma after neodymium-yttrium-aluminum-garnet laser lysis of vitreous floaters.

PubMed

Cowan, Lisa A; Khine, Kay T; Chopra, Vikas; Fazio, Doreen T; Francis, Brian A

2015-01-01

To illustrate 3 cases of chronic open-angle glaucoma secondary to the neodymium-yttrium-aluminum-garnet (Nd:YAG) laser vitreolysis procedure for symptomatic vitreous floaters. Observational case series. Location of the study was the Doheny Eye Institute. Three eyes of 2 patients who developed chronic open-angle glaucoma after Nd:YAG vitreolysis for symptomatic floaters presenting with very high intraocular pressure (IOP >40 mm Hg) were selected. The time from the laser treatment to the onset of elevated pressure ranges from 1 week to 8 months. There was no associated inflammation, steroid use, or other identifiable cause of chronic IOP elevation. All eyes were treated initially with glaucoma medication, followed by selective laser trabeculoplasty (SLT) and eventually glaucoma surgery (Trabectome) in 2 eyes for disease management. In all eyes, intraocular pressures were eventually stabilized within a normal pressure range from 18 to 38 months following Nd:YAG vitreolysis. At the latest follow-up post surgery, all eyes had intraocular pressures of 22 mm Hg or less with or without medications. Secondary open-angle glaucoma is a complication of Nd:YAG vitreolysis for symptomatic floaters that may present with an increase in intraocular pressure immediately, or many months after the surgery. Furthermore this complication may be permanent and require chronic medical therapy or glaucoma surgery. Copyright © 2015 Elsevier Inc. All rights reserved.

A target field design of open multi-purpose RF coil for musculoskeletal MR imaging at 3T.

PubMed

Gao, Fei; Zhang, Rui; Zhou, Diange; Wang, Xiaoying; Huang, Kefu; Zhang, Jue

2016-10-01

Musculoskeletal MR imaging under multi-angle situations plays an increasingly important role in assessing joint and muscle tissues system. However, there are still limitations due to the closed structures of most conventional RF coils. In this study, a time-harmonic target-field method was employed to design open multi-purpose coil (OMC) for multi-angle musculoskeletal MR imaging. The phantom imaging results suggested that the proposed OMC could achieve homogeneously distributed magnetic field and high signal-to-noise ratio (SNR) of 239.04±0.83 in the region of interest (ROI). The maximum temperature in the heating hazard test was 16°C lower than the standard regulation, which indicated the security of the designed OMC. Furthermore, to demonstrate the effectiveness of the proposed OMC for musculoskeletal MR imaging, especially for multi-angle imaging, a healthy volunteer was examined for MR imaging of elbow, ankle and knee using OMC. The in vivo imaging results showed that the proposed OMC is effective for MR imaging of musculoskeletal tissues at different body parts, with satisfied B1 field homogeneity and SNR. Moreover, the open structure of the OMC could provide a large joint movement region. The proposed open multi-purpose coil is feasible for musculoskeletal MR imaging, and potentially, it is more suitable for the evaluation of musculoskeletal tissues under multi-angle conditions. Copyright © 2016. Published by Elsevier Inc.

46 CFR 42.20-12 - Conditions of equilibrium.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., heel, and trim, is below the lower edge of any opening through which progressive flooding can take... angle of heel. The angle of heel due to unsymmetrical flooding does not exceed 15 degrees. If no part of the deck is immersed, an angle of heel of up to 17 degrees may be accepted. (d) Metacentric height...

46 CFR 42.20-12 - Conditions of equilibrium.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., heel, and trim, is below the lower edge of any opening through which progressive flooding can take... angle of heel. The angle of heel due to unsymmetrical flooding does not exceed 15 degrees. If no part of the deck is immersed, an angle of heel of up to 17 degrees may be accepted. (d) Metacentric height...

Demonstration of angle widening using EyeCam after laser peripheral iridotomy in eyes with angle closure.

PubMed

Perera, Shamira A; Quek, Desmond T; Baskaran, Mani; Tun, Tin A; Kumar, Rajesh S; Friedman, David S; Aung, Tin

2010-06-01

To evaluate EyeCam in detecting changes in angle configuration after laser peripheral iridotomy (LPI) in comparison to gonioscopy, the reference standard. Prospective comparative study. Twenty-four subjects (24 eyes) with primary angle-closure glaucoma (PACG) were recruited. Gonioscopy and EyeCam (Clarity Medical Systems) imaging of all 4 angle quadrants were performed, before and 2 weeks after LPI. Images were graded according to angle structures visible by an observer masked to clinical data or the status of LPI, and were performed in a random order. Angle closure in a quadrant was defined as the inability to visualize the posterior trabecular meshwork. We determined the number of quadrants with closed angles and the mean number of clock hours of angle closure before and after LPI in comparison to gonioscopy. Using EyeCam, all 24 eyes showed at least 1 quadrant of angle widening after LPI. The mean number of clock hours of angle closure decreased significantly, from 8.15 +/- 3.47 clock hours before LPI to 1.75 +/- 2.27 clock hours after LPI (P < .0001, Wilcoxon signed rank test). Overall, gonioscopy showed 1.0 +/- 1.41 (95% CI, 0.43-1.57) quadrants opening from closed to open after LPI compared to 2.0 +/- 1.28 (95% CI, 1.49-2.51, P = .009) quadrants with EyeCam. Intra-observer reproducibility of grading the extent of angle closure in clock hours in EyeCam images was moderate to good (intraclass correlation coefficient 0.831). EyeCam may be used to document changes in angle configuration after LPI in eyes with PACG. Copyright 2010 Elsevier Inc. All rights reserved.

[Uveitic Secondary Glaucoma].

PubMed

Lommatzsch, Claudia; Heinz, Carsten

2018-05-01

An intraocular pressure increase with development of glaucomatous damage is a common complication of uveitis. The prevalence has a wide range depending on various factors such as the underlying uveitis type and the duration of the disease. Pathogenetically, a distinction must be made between a secondary angle closure component and the more frequently occurring open-angle glaucoma. In diagnostics, in addition to the clinical optic nerve head assessment, perimetry and tonometry, the use of imaging examination equipment, such as OCT and HRT, are recommended. In the context of uveitic glaucoma, it must be considered in the evaluation, because the glaucoma-typical changes are generally less pronounced or can be concealed by retinal swelling in comparison with other forms of glaucoma. Therapeutically, drug therapy in the form of eye drops continues to be a first-line recommendation, with the use of topical carbonic anhydrase inhibitors or beta-blockers primarily preferred, depending on the contraindications. An operative therapy follows after unsuccessful or inadequate conservative therapy: the adequate surgical technique depends on the respective finding and includes actually techniques such as filtering procedures and glaucoma drainage devices. Georg Thieme Verlag KG Stuttgart · New York.

Positioning and joining of organic single-crystalline wires

PubMed Central

Wu, Yuchen; Feng, Jiangang; Jiang, Xiangyu; Zhang, Zhen; Wang, Xuedong; Su, Bin; Jiang, Lei

2015-01-01

Organic single-crystal, one-dimensional materials can effectively carry charges and/or excitons due to their highly ordered molecule packing, minimized defects and eliminated grain boundaries. Controlling the alignment/position of organic single-crystal one-dimensional architectures would allow on-demand photon/electron transport, which is a prerequisite in waveguides and other optoelectronic applications. Here we report a guided physical vapour transport technique to control the growth, alignment and positioning of organic single-crystal wires with the guidance of pillar-structured substrates. Submicrometre-wide, hundreds of micrometres long, highly aligned, organic single-crystal wire arrays are generated. Furthermore, these organic single-crystal wires can be joined within controlled angles by varying the pillar geometries. Owing to the controllable growth of organic single-crystal one-dimensional architectures, we can present proof-of-principle demonstrations utilizing joined wires to allow optical waveguide through small radii of curvature (internal angles of ~90–120°). Our methodology may open a route to control the growth of organic single-crystal one-dimensional materials with potential applications in optoelectronics. PMID:25814032

Design of Bi-Directional Hydrofoils for Tidal Current Turbines

NASA Astrophysics Data System (ADS)

Nedyalkov, Ivaylo; Wosnik, Martin

2015-11-01

Tidal Current Turbines operate in flows which reverse direction. Bi-directional hydrofoils have rotational symmetry and allow such turbines to operate without the need for pitch or yaw control, decreasing the initial and maintenance costs. A numerical test-bed was developed to automate the simulations of hydrofoils in OpenFOAM and was utilized to simulate the flow over eleven classes of hydrofoils comprising a total of 700 foil shapes at different angles of attack. For promising candidate foil shapes physical models of 75 mm chord and 150 mm span were fabricated and tested in the University of New Hampshire High-Speed Cavitation Tunnel (HiCaT). The experimental results were compared to the simulations for model validation. The numerical test-bed successfully generated simulations for a wide range of foil shapes, although, as expected, the k - ω - SST turbulence model employed here was not adequate for some of the foils and for large angles of attack at which separation occurred. An optimization algorithm is currently being coupled with the numerical test-bed and additional turbulence models will be implemented in the future.

Breakthrough in 4π ion emission mechanism understanding in plasma focus devices.

PubMed

Sohrabi, Mehdi; Zarinshad, Arefe; Habibi, Morteza

2016-12-12

Ion emission angular distribution mechanisms in plasma focus devices (PFD) have not yet been well developed and understood being due to the lack of an efficient wide-angle ion distribution image detection system to characterize a PFD space in detail. Present belief is that the acceleration of ions points from "anode top" upwards in forward direction within a small solid angle. A breakthrough is reported in this study, by mega-size position-sensitive polycarbonate ion image detection systems invented, on discovery of 4π ion emission from the "anode top" in a PFD space after plasma pinch instability and radial run-away of ions from the "anode cathodes array" during axial acceleration of plasma sheaths before the radial phase. These two ion emission source mechanisms behave respectively as a "Point Ion Source" and a "Line Ion Source" forming "Ion Cathode Shadows" on mega-size detectors. We believe that the inventions and discoveries made here will open new horizons for advanced ion emission studies towards better mechanisms understanding and in particular will promote efficient applications of PFDs in medicine, science and technology.

Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton

NASA Astrophysics Data System (ADS)

Fanelli, C.; Cisbani, E.; Hamilton, D. J.; Salmé, G.; Wojtsekhowski, B.; Ahmidouch, A.; Annand, J. R. M.; Baghdasaryan, H.; Beaufait, J.; Bosted, P.; Brash, E. J.; Butuceanu, C.; Carter, P.; Christy, E.; Chudakov, E.; Danagoulian, S.; Day, D.; Degtyarenko, P.; Ent, R.; Fenker, H.; Fowler, M.; Frlez, E.; Gaskell, D.; Gilman, R.; Horn, T.; Huber, G. M.; de Jager, C. W.; Jensen, E.; Jones, M. K.; Kelleher, A.; Keppel, C.; Khandaker, M.; Kohl, M.; Kumbartzki, G.; Lassiter, S.; Li, Y.; Lindgren, R.; Lovelace, H.; Luo, W.; Mack, D.; Mamyan, V.; Margaziotis, D. J.; Markowitz, P.; Maxwell, J.; Mbianda, G.; Meekins, D.; Meziane, M.; Miller, J.; Mkrtchyan, A.; Mkrtchyan, H.; Mulholland, J.; Nelyubin, V.; Pentchev, L.; Perdrisat, C. F.; Piasetzky, E.; Prok, Y.; Puckett, A. J. R.; Punjabi, V.; Shabestari, M.; Shahinyan, A.; Slifer, K.; Smith, G.; Solvignon, P.; Subedi, R.; Wesselmann, F. R.; Wood, S.; Ye, Z.; Zheng, X.

2015-10-01

Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θcmp=70 ° . The longitudinal transfer KLL, measured to be 0.645 ±0.059 ±0.048 , where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ˜3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fanelli, C.; Cisbani, E.; Hamilton, D. J.

Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of theta(p)(cm) cm = 70 degrees. The longitudinal transfer K-LL, measured to be 0.645 +/- 0.059 +/- 0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying themore » spin of the proton. However, the observed value is similar to 3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.« less

Molecular Dynamics Simulations of Ligand-Induced Flap Conformational Changes in Cathepsin-D-A Comparative Study.

PubMed

Arodola, Olayide A; Soliman, Mahmoud E S

2016-11-01

The flap region in aspartic proteases is a unique structural feature to this class of enzymes, and found to have a profound impact on protein overall structure, function, and dynamics. Understanding the structure and dynamic behavior of the flap regions is crucial in the design of selective inhibitors against aspartic proteases. Cathepsin-D, an aspartic protease enzyme, has been implicated in a long list of degenerative diseases as well as breast cancer progression. Presented herein, for the first time, is a comprehensive description of the conformational flap dynamics of cathepsin-D using a comparative 50 ns "multiple" molecular dynamics simulations. Diverse collective metrics were proposed to accurately define flap dynamics. These are distance d1 between the flap tips residues (Gly79 and Met301); dihedral angle ϕ; in addition to TriCα angles Gly79-Asp33-Asp223, θ1 , and Gly79-Asp223-Met301, θ2 . The maximum distance attained throughout the simulation was 17.42 and 11.47 Å for apo and bound cathepsin-D, respectively, while the minimum distance observed was 8.75 and 6.32 Å for apo and bound cathepsin-D, respectively. The movement of the flap as well as the twist of the active pocket can properly be explained by measuring the angle, θ1 , between Gly79-Asp33-Met301 and correlating it with the distance Cα of the flap tip residues. The asymmetrical opening of the binding cavity was best described by the large shift of -6.26° to +20.94° in the dihedral angle, ϕ, corresponding to the full opening of the flap at a range of 31-33 ns. A wide-range of post-dynamic analyses was also applied in this report to supplement our findings. We believe that this report would augment current efforts in designing potent structure-based inhibitors against cathepsin-D in the treatment of breast cancer and other degenerative diseases. J. Cell. Biochem. 117: 2643-2657, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Dental and skeletal components of Class II open bite treatment with a modified Thurow appliance

PubMed Central

Jacob, Helder Baldi; dos Santos-Pinto, Ary; Buschang, Peter H.

2014-01-01

Introduction Due to the lack of studies that distinguish between dentoalveolar and basal changes caused by the Thurow appliance, this clinical study, carried out by the School of Dentistry - State University of São Paulo/Araraquara, aimed at assessing the dental and skeletal changes induced by modified Thurow appliance. Methods The sample included an experimental group comprising 13 subjects aged between 7 and 10 years old, with Class II malocclusion and anterior open bite, and a control group comprising 22 subjects similar in age, sex and mandibular plane angle. Maxillary/mandibular, horizontal/vertical, dental/skeletal movements (ANS, PNS, U1, U6, Co, Go, Pog, L1, L6) were assessed, based on 14 landmarks, 8 angles (S-N-ANS, SNA, PPA, S-N-Pog, SNB, MPA, PP/MPA, ANB) and 3 linear measures (N-Me, ANS-Me, S-Go). Results Treatment caused significantly greater angle decrease between the palatal and the mandibular plane of the experimental group, primarily due to an increase in the palatal plane angle. ANB, SNA and S-N-ANS angles significantly decreased more in patients from the experimental group. PNS was superiorly remodeled. Lower face height (ANS-Me) decreased in the experimental group and increased in the control group. Conclusions The modified Thurow appliance controlled vertical and horizontal displacements of the maxilla, rotated the maxilla and improved open bite malocclusion, decreasing lower facial height. PMID:24713556

Open-ocean fish reveal an omnidirectional solution to camouflage in polarized environments.

PubMed

Brady, Parrish C; Gilerson, Alexander A; Kattawar, George W; Sullivan, James M; Twardowski, Michael S; Dierssen, Heidi M; Gao, Meng; Travis, Kort; Etheredge, Robert Ian; Tonizzo, Alberto; Ibrahim, Amir; Carrizo, Carlos; Gu, Yalong; Russell, Brandon J; Mislinski, Kathryn; Zhao, Shulei; Cummings, Molly E

2015-11-20

Despite appearing featureless to our eyes, the open ocean is a highly variable environment for polarization-sensitive viewers. Dynamic visual backgrounds coupled with predator encounters from all possible directions make this habitat one of the most challenging for camouflage. We tested open-ocean crypsis in nature by collecting more than 1500 videopolarimetry measurements from live fish from distinct habitats under a variety of viewing conditions. Open-ocean fish species exhibited camouflage that was superior to that of both nearshore fish and mirrorlike surfaces, with significantly higher crypsis at angles associated with predator detection and pursuit. Histological measurements revealed that specific arrangements of reflective guanine platelets in the fish's skin produce angle-dependent polarization modifications for polarocrypsis in the open ocean, suggesting a mechanism for natural selection to shape reflectance properties in this complex environment. Copyright © 2015, American Association for the Advancement of Science.

The Properties of Extragalactic Radio Jets

NASA Astrophysics Data System (ADS)

Finke, Justin

2018-01-01

I show that by assuming a standard Blandford-Konigl jet, it is possible to determine the speed (bulk Lorentz factor) and orientation (angle to the line of sight) of self-similar parsec-scale blazar jets by using four measured quantities: the core radio flux, the extended radio flux, the magnitude of the core shift between two frequencies, and the apparent jet opening angle. Once the bulk Lorentz factor and angle to the line of sight of a jet are known, it is possible to compute their Doppler factor, magnetic field, and intrinsic jet opening angle. I use data taken from the literature and marginalize over nuisance parameters associated with the electron distribution and equipartition, to compute these quantities, albeit with large errors. The results have implications for the resolution of the TeV BL Lac Doppler factor crisis and the production of jets from magnetically arrested disks.

Joint kinematic calculation based on clinical direct kinematic versus inverse kinematic gait models.

PubMed

Kainz, H; Modenese, L; Lloyd, D G; Maine, S; Walsh, H P J; Carty, C P

2016-06-14

Most clinical gait laboratories use the conventional gait analysis model. This model uses a computational method called Direct Kinematics (DK) to calculate joint kinematics. In contrast, musculoskeletal modelling approaches use Inverse Kinematics (IK) to obtain joint angles. IK allows additional analysis (e.g. muscle-tendon length estimates), which may provide valuable information for clinical decision-making in people with movement disorders. The twofold aims of the current study were: (1) to compare joint kinematics obtained by a clinical DK model (Vicon Plug-in-Gait) with those produced by a widely used IK model (available with the OpenSim distribution), and (2) to evaluate the difference in joint kinematics that can be solely attributed to the different computational methods (DK versus IK), anatomical models and marker sets by using MRI based models. Eight children with cerebral palsy were recruited and presented for gait and MRI data collection sessions. Differences in joint kinematics up to 13° were found between the Plug-in-Gait and the gait 2392 OpenSim model. The majority of these differences (94.4%) were attributed to differences in the anatomical models, which included different anatomical segment frames and joint constraints. Different computational methods (DK versus IK) were responsible for only 2.7% of the differences. We recommend using the same anatomical model for kinematic and musculoskeletal analysis to ensure consistency between the obtained joint angles and musculoskeletal estimates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Current concepts on primary open-angle glaucoma genetics: a contribution to disease pathophysiology and future treatment

PubMed Central

Gemenetzi, M; Yang, Y; Lotery, A J

2012-01-01

Glaucoma is a common, complex, heterogenous disease and it constitutes the major cause of irreversible blindness worldwide. Primary open-angle glaucoma (POAG) is the most common type of glaucoma in all populations. Most of the molecular mechanisms leading to POAG development are still unknown. Gene mutations in various populations have been identified by genetic studies and a genetic basis for glaucoma pathogenesis has been established. Linkage analysis and association studies are genetic approaches in the investigation of the genetic basis of POAG. Genome-wide association studies (GWAS) are more powerful compared with linkage analysis in discovering genes of small effect that might contribute to the development of the disease. POAG links to at least 20 genetic loci, but only 2 genes identified in these loci, myocilin and optineurin, are considered as well-established glaucoma-causing genes, whereas the role of other loci, genes, and variants implicated in the development of POAG remains controversial. Gene mutations associated with POAG result in retinal ganglion cell death, which is the common outcome of pathogenetic mechanisms in glaucoma. In future, if the sensitivity and specificity of genotyping increases, it may be possible to screen individuals routinely for disease susceptibility. This review is an update on the latest progress of genetic studies associated with POAG. It emphasizes the correlation of recent achievements in genetics with glaucoma pathophysiology, glaucoma treatment perspectives, and the possibility of future prevention of irreversible visual loss caused by the disease. PMID:22173078

Assessment of β-zone peripapillary atrophy by optical coherence tomography and scanning laser ophthalmoscopy imaging in glaucoma patients

PubMed Central

Seidensticker, Florian; Reznicek, Lukas; Mann, Thomas; Hübert, Irene; Kampik, Anselm; Ulbig, Michael; Hirneiss, Christoph; Neubauer, Aljoscha S; Kernt, Marcus

2014-01-01

Purpose To assess β-zone peripapillary atrophy (β-PPA) using spectral domain optical coherence tomography (SD-OCT), scanning laser ophthalmoscopy (SLO), and fundus auto-fluorescence (FAF) imaging in patients with primary open-angle glaucoma with advanced glaucomatous visual field defects. Methods A consecutive, prospective series of 82 study eyes with primary open-angle glaucoma were included in this study. All study participants underwent a full ophthalmic examination followed by SD-OCT, wide-field SLO, and FAF imaging of the optic nerve head and the peripapillary region. Results Eighty-four glaucomatous eyes were included in our prospective study. Correlation analyses for horizontally and vertically obtained β-PPA for all three imaging modalities (color SLO, FAF, and SD-OCT) revealed highest correlations between FAF and color SLO (Pearson correlation coefficient: 0.904 [P<0.001] for horizontal β-PPA and 0.786 [P<0.001] for vertical β-PPA). Bland–Altman plotting revealed highest agreements between color SLO and FAF, with −2.1 pixels ±1.96 standard deviation (SD) for horizontal β-PPA, SD: 10.5 pixels and 2.4 pixels ±1.96 SD for vertical β-PPA. Conclusion β-PPA can be assessed using en-face SLO and cross-sectional SD-OCT imaging. Correlation analyses revealed highest correlations between color SLO and FAF imaging, while correlations between SLO and SD-OCT were weak. A more precise structural definition of β-PPA is needed. PMID:25061270

The Properties of Short Gamma-Ray Burst Jets Triggered by Neutron Star Mergers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murguia-Berthier, Ariadna; Ramirez-Ruiz, Enrico; Montes, Gabriela

The most popular model for short gamma-ray bursts (sGRBs) involves the coalescence of binary neutron stars. Because the progenitor is actually hidden from view, we must consider under which circumstances such merging systems are capable of producing a successful sGRB. Soon after coalescence, winds are launched from the merger remnant. In this paper, we use realistic wind profiles derived from global merger simulations in order to investigate the interaction of sGRB jets with these winds using numerical simulations. We analyze the conditions for which these axisymmetric winds permit relativistic jets to break out and produce an sGRB. We find thatmore » jets with luminosities comparable to those observed in sGRBs are only successful when their half-opening angles are below ≈20°. This jet collimation mechanism leads to a simple physical interpretation of the luminosities and opening angles inferred for sGRBs. If wide, low-luminosity jets are observed, they might be indicative of a different progenitor avenue such as the merger of a neutron star with a black hole. We also use the observed durations of sGRB to place constraints on the lifetime of the wind phase, which is determined by the time it takes the jet to break out. In all cases we find that the derived limits argue against completely stable remnants for binary neutron star mergers that produce sGRBs.« less

PROSPECTS FOR JOINT GRAVITATIONAL WAVE AND SHORT GAMMA-RAY BURST OBSERVATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, J.; Evans, H.; Fairhurst, S.

2015-08-10

We present a detailed evaluation of the expected rate of joint gravitational-wave (GW) and short gamma-ray burst (GRB) observations over the coming years. We begin by evaluating the improvement in distance sensitivity of the GW search that arises from using the GRB observation to restrict the time and sky location of the source. We argue that this gives a 25% increase in sensitivity when compared to an all-sky, all-time search, corresponding to more than double the number of detectable GW signals associated with GRBs. Using this, we present the expected rate of joint observations with the advanced LIGO and Virgomore » instruments, taking into account the expected evolution of the GW detector network. We show that in the early advanced GW detector observing runs, from 2015 to 2017, there is only a small chance of a joint observation. However, as the detectors approach their design sensitivities, there is a good chance of joint observations, provided wide field GRB satellites, such as Fermi and the Inter planetary Network, continue operation. The rate will also depend critically upon the nature of the progenitor, with neutron star-black hole systems observable to greater distances than double neutron star systems. The relative rate of binary mergers and GRBs will depend upon the jet opening angle of GRBs. Consequently, joint observations, as well as accurate measurement of both the GRB rate and binary merger rates, will allow for an improved estimation of the opening angle of GRBs.« less

A comparison of latanoprost monotherapy with a combination therapy of timolol/dorzolamide in patients with primary open-angle glaucoma.

PubMed

Caça, Ihsan; Simsek, Hüseyin; Unlü, Kaan; Ari, Seyhmus; Keklikçi, Ugur

2006-01-01

We compared latanoprost monotherapy therapy with timolol/ dorzolamide in patients with primary open-angle glaucoma to evaluate the effects on intraocular pressure (IOP) and occurrence of adverse events. IOP and topical side effects were evaluated at the beginning, first, and third months. Mean IOP was decreased at the third month. The most common side effect was hyperemia (43.6%). We concluded that latanoprost reduces IOP better than fixed combination and its topical side effects are tolerable.

Robust design study on the wide angle lens with free distortion for mobile lens

NASA Astrophysics Data System (ADS)

Kim, Taeyoung; Yong, Liu; Xu, Qing

2017-10-01

Recently new trend applying wide angle in mobile imaging lens is attracting. Specially, customer requirements for capturing wider scene result that a field of view of lens be wider than 100deg. Introduction of retro-focus type lens in mobile imaging lens is required. However, imaging lens in mobile phone always face to many constraints such as lower total length, low F/# and higher performance. The sensitivity for fabrication may become more severe because of wide angle FOV. In this paper, we investigate an optical lens design satisfy all requirements for mobile imaging lens. In order to accomplish Low cost and small depth of optical system, we used plastic materials for all element and the productivity is considered for realization. The lateral color is minimized less than 2 pixels and optical distortion is less than 5%. Also, we divided optical system into 2 part for robust design. The compensation between 2 groups can help us to increase yield in practice. The 2 group alignment for high yield may be a promising solution for wide angle lens.

Nondestructive hydrogen analysis of steam-oxidized Zircaloy-4 by wide-angle neutron scattering

NASA Astrophysics Data System (ADS)

Yan, Yong; Qian, Shuo; Garrison, Ben; Smith, Tyler; Kim, Peter

2018-04-01

A nondestructive neutron scattering method to precisely measure the hydrogen content in high-temperature steam-oxidized Zircaloy-4 cladding was developed. Zircaloy-4 cladding was used to produce hydrided specimens with hydrogen content up to ≈500 wppm. Following hydrogen charging, the hydrogen content of the hydrided specimens was measured using the vacuum hot extraction method, by which the samples with desired hydrogen concentrations were selected for the neutron study. The hydrided samples were then oxidized in steam up to ≈6.0 wt. % at 1100 °C. Optical microscopy shows that our hydriding procedure results in uniform distribution of circumferential hydrides across the wall thickness, and uniform oxide layers were formed on the sample surfaces by the steam oxidation. Small- and wide-angle neutron scattering were simultaneously performed to provide a quick (less than an hour per sample) measurement of the hydrogen content in various types of hydrided and oxidized Zircaloy-4. Our study demonstrates that the hydrogen in pre-oxidized Zircaloy-4 cladding can be measured very accurately by both small- and wide-angle neutron scattering. For steam-oxidized samples, the small-angle neutron scattering is contaminated with coherent scattering from additional structural features induced by the steam oxidation. However, the scattering intensity of the wide-angle neutron scattering increases proportionally with the hydrogen charged in the samples. The hydrogen content and wide-angle neutron scattering intensity are highly linearly correlated for the oxidized cladding samples examined in this work, and can be used to precisely determine the hydrogen content in steam-oxidized Zircaloy-4 samples. Hydrogen contents determined by neutron scattering of oxidation samples were also found to be consistent with the results of chemical analysis within acceptable margins for error.

Nondestructive hydrogen analysis of steam-oxidized Zircaloy-4 by wide-angle neutron scattering

DOE PAGES

Yan, Yong; Qian, Shuo; Garrison, Ben; ...

2018-04-15

In this study, a nondestructive neutron scattering method to precisely measure the hydrogen content in high-temperature steam-oxidized Zircaloy-4 cladding was developed. Zircaloy-4 cladding was used to produce hydrided specimens with hydrogen content up to ≈500 wppm. Following hydrogen charging, the hydrogen content of the hydrided specimens was measured using the vacuum hot extraction method, by which the samples with desired hydrogen concentrations were selected for the neutron study. The hydrided samples were then oxidized in steam up to ≈6.0wt. % at 1100°C. Optical microscopy shows that our hydriding procedure results in uniform distribution of circumferential hydrides across the wall thickness,more » and uniform oxide layers were formed on the sample surfaces by the steam oxidation. Small- and wide-angle neutron scattering were simultaneously performed to provide a quick (less than an hour per sample) measurement of the hydrogen content in various types of hydrided and oxidized Zircaloy-4. Our study demonstrates that the hydrogen in pre-oxidized Zircaloy-4 cladding can be measured very accurately by both small- and wide-angle neutron scattering. For steam-oxidized samples, the small-angle neutron scattering is contaminated with coherent scattering from additional structural features induced by the steam oxidation. However, the scattering intensity of the wide-angle neutron scattering increases proportionally with the hydrogen charged in the samples. The hydrogen content and wide-angle neutron scattering intensity are highly linearly correlated for the oxidized cladding samples examined in this work, and can be used to precisely determine the hydrogen content in steam-oxidized Zircaloy-4 samples. Hydrogen contents determined by neutron scattering of oxidation samples were also found to be consistent with the results of chemical analysis within acceptable margins for error.« less

Nondestructive hydrogen analysis of steam-oxidized Zircaloy-4 by wide-angle neutron scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Yong; Qian, Shuo; Garrison, Ben

In this study, a nondestructive neutron scattering method to precisely measure the hydrogen content in high-temperature steam-oxidized Zircaloy-4 cladding was developed. Zircaloy-4 cladding was used to produce hydrided specimens with hydrogen content up to ≈500 wppm. Following hydrogen charging, the hydrogen content of the hydrided specimens was measured using the vacuum hot extraction method, by which the samples with desired hydrogen concentrations were selected for the neutron study. The hydrided samples were then oxidized in steam up to ≈6.0wt. % at 1100°C. Optical microscopy shows that our hydriding procedure results in uniform distribution of circumferential hydrides across the wall thickness,more » and uniform oxide layers were formed on the sample surfaces by the steam oxidation. Small- and wide-angle neutron scattering were simultaneously performed to provide a quick (less than an hour per sample) measurement of the hydrogen content in various types of hydrided and oxidized Zircaloy-4. Our study demonstrates that the hydrogen in pre-oxidized Zircaloy-4 cladding can be measured very accurately by both small- and wide-angle neutron scattering. For steam-oxidized samples, the small-angle neutron scattering is contaminated with coherent scattering from additional structural features induced by the steam oxidation. However, the scattering intensity of the wide-angle neutron scattering increases proportionally with the hydrogen charged in the samples. The hydrogen content and wide-angle neutron scattering intensity are highly linearly correlated for the oxidized cladding samples examined in this work, and can be used to precisely determine the hydrogen content in steam-oxidized Zircaloy-4 samples. Hydrogen contents determined by neutron scattering of oxidation samples were also found to be consistent with the results of chemical analysis within acceptable margins for error.« less

Subduction erosion off central Java: transition from accretion to erosion manifested by wide-angle seismic studies

NASA Astrophysics Data System (ADS)

Wittwer, A.; Flueh, E.; Rabbel, W.; Wagner, D.

2006-12-01

In this study, offshore wide-angle data acquired by ocean bottom instruments of a combined onshore- offshore investigation of the tectonic framework of central Java will be presented. The joint interdisciplinary project MERAMEX (Merapi Amphibious Experiment) was carried out in order to characterize the subduction of the Indo-Australian plate beneath Eurasia. The interpretation of three wide-angle data profiles, modelled with forward raytracing, indicates that the subduction of the Roo Rise with its thickened oceanic crust strongly influences the subduction zone. The dip angle of the downgoing oceanic plate is 10° and its crustal thickness increases to the east from 8 km to 9 km between both dip profiles off central Java. Large scale forearc uplift is manifested in isolated forearc highs, reaching water depths of only 1000 m compared to 2000 m water depth off western Java, and results from oceanic basement relief subduction. A broad band of seamounts trends E-W at approximately 10°S. Its incipient subduction off central Java causes frontal erosion of the margin here and leads to mass wasting due to oversteepening of the upper trench wall. A suite of wide-angle profiles off southern Sumatra to central Java indicates a clear change in the tectonic environment between longitude 108°E and 109°E. The well-developed accretionary wedge off southern Sumatra and western Java changes into a small frontal prism with steep slope angles of the upper plate off central Java.

Static balance according to hip joint angle of unsupported leg during one-leg standing.

PubMed

Cha, Ju-Hyung; Kim, Jang-Joon; Ye, Jae-Gwan; Lee, Seul-Ji; Hong, Jeong-Mi; Choi, Hyun-Kyu; Choi, Ho-Suk; Shin, Won-Seob

2017-05-01

[Purpose] This study aimed to determine static balance according to hip joint angle of the unsupported leg during one-leg standing. [Subjects and Methods] Subjects included 45 healthy adult males and females in their 20s. During one-leg standing on the non-dominant leg, the position of the unsupported leg was classified according to hip joint angles of point angle was class. Static balance was then measured using a force plate with eyes open and closed. The total length, sway velocity, maximum deviation, and velocity on the mediolateral and anteroposterior axes of center of pressure were measured. [Results] In balance assessment with eyes open, there were significant differences between groups according to hip joint angle, except for maximum deviation on the anteroposterior axis. In balance assessment with eyes closed, there were significant differences between total length measurements at 0° and 30°, 60° and between 30° and 90°. There were significant differences between sway velocity measurements at 0° and 30° and between 30° and 90°. [Conclusion] Thus, there were differences in static balance according to hip joint angle. It is necessary to clearly identify the hip joint angle during one-leg standing testing.

Traffic Sign Recognition with Invariance to Lighting in Dual-Focal Active Camera System

NASA Astrophysics Data System (ADS)

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

In this paper, we present an automatic vision-based traffic sign recognition system, which can detect and classify traffic signs at long distance under different lighting conditions. To realize this purpose, the traffic sign recognition is developed in an originally proposed dual-focal active camera system. In this system, a telephoto camera is equipped as an assistant of a wide angle camera. The telephoto camera can capture a high accuracy image for an object of interest in the view field of the wide angle camera. The image from the telephoto camera provides enough information for recognition when the accuracy of traffic sign is low from the wide angle camera. In the proposed system, the traffic sign detection and classification are processed separately for different images from the wide angle camera and telephoto camera. Besides, in order to detect traffic sign from complex background in different lighting conditions, we propose a type of color transformation which is invariant to light changing. This color transformation is conducted to highlight the pattern of traffic signs by reducing the complexity of background. Based on the color transformation, a multi-resolution detector with cascade mode is trained and used to locate traffic signs at low resolution in the image from the wide angle camera. After detection, the system actively captures a high accuracy image of each detected traffic sign by controlling the direction and exposure time of the telephoto camera based on the information from the wide angle camera. Moreover, in classification, a hierarchical classifier is constructed and used to recognize the detected traffic signs in the high accuracy image from the telephoto camera. Finally, based on the proposed system, a set of experiments in the domain of traffic sign recognition is presented. The experimental results demonstrate that the proposed system can effectively recognize traffic signs at low resolution in different lighting conditions.

On the Collisionless Asymmetric Magnetic Reconnection Rate

NASA Astrophysics Data System (ADS)

Liu, Yi-Hsin; Hesse, M.; Cassak, P. A.; Shay, M. A.; Wang, S.; Chen, L.-J.

2018-04-01

A prediction of the steady state reconnection electric field in asymmetric reconnection is obtained by maximizing the reconnection rate as a function of the opening angle made by the upstream magnetic field on the weak magnetic field (magnetosheath) side. The prediction is within a factor of 2 of the widely examined asymmetric reconnection model (Cassak & Shay, 2007, https://doi.org/10.1063/1.2795630) in the collisionless limit, and they scale the same over a wide parameter regime. The previous model had the effective aspect ratio of the diffusion region as a free parameter, which simulations and observations suggest is on the order of 0.1, but the present model has no free parameters. In conjunction with the symmetric case (Liu et al., 2017, https://doi.org/10.1103/PhysRevLett.118.085101), this work further suggests that this nearly universal number 0.1, essentially the normalized fast-reconnection rate, is a geometrical factor arising from maximizing the reconnection rate within magnetohydrodynamic-scale constraints.

Numerical investigation of the variable nozzle effect on the mixed flow turbine performance characteristics

NASA Astrophysics Data System (ADS)

Meziri, B.; Hamel, M.; Hireche, O.; Hamidou, K.

2016-09-01

There are various matching ways between turbocharger and engine, the variable nozzle turbine is the most significant method. The turbine design must be economic with high efficiency and large capacity over a wide range of operational conditions. These design intents are used in order to decrease thermal load and improve thermal efficiency of the engine. This paper presents an original design method of a variable nozzle vane for mixed flow turbines developed from previous experimental and numerical studies. The new device is evaluated with a numerical simulation over a wide range of rotational speeds, pressure ratios, and different vane angles. The compressible turbulent steady flow is solved using the ANSYS CFX software. The numerical results agree well with experimental data in the nozzleless configuration. In the variable nozzle case, the results show that the turbine performance characteristics are well accepted in different open positions and improved significantly in low speed regime and at low pressure ratio.

Spatially oriented plasmonic ‘nanograter’ structures

PubMed Central

Liu, Zhe; Cui, Ajuan; Gong, Zhijie; Li, Hongqiang; Xia, Xiaoxiang; Shen, Tiehan H.; Li, Junjie; Yang, Haifang; Li, Wuxia; Gu, Changzhi

2016-01-01

One of the key motivations in producing 3D structures has always been the realization of metamaterials with effective constituent properties that can be tuned in all propagation directions at various frequencies. Here, we report the investigation of spatially oriented “Nanograter” structures with orientation-dependent responses over a wide spectrum by focused-ion-beam based patterning and folding of thin film nanostructures. Au nano units of different shapes, standing along specifically designated orientations, were fabricated. Experimental measurements and simulation results show that such structures offer an additional degree of freedom for adjusting optical properties with the angle of inclination, in additional to the size of the structures. The response frequency can be varied in a wide range (8 μm–14 μm) by the spatial orientation (0°–180°) of the structures, transforming the response from magnetic into electric coupling. This may open up prospects for the fabrication of 3D nanostructures as optical interconnects, focusing elements and logic elements, moving toward the realization of 3D optical circuits. PMID:27357610

Hemocompatibility improvement of poly(ethylene terephthalate) via self-polymerization of dopamine and covalent graft of zwitterions.

PubMed

Cai, Xianmei; Yuan, Jiang; Chen, Shuangchun; Li, Pengfei; Li, Li; Shen, Jian

2014-03-01

Poly (ethylene terephthalate) (PET) has been widely adopted as a scaffold biomaterial, but further hemocompatibility improvement is still needed for wide biomedical applications. Inspired by the composition of adhesive proteins in mussels, we propose to use self-polymerized dopamine to form a surface-adherent polydopamine layer onto PET sheet, followed by Michael addition with N,N-dimethylethylenediamine (DMDA) to build tertiary amine, and final zwitterions(sulfobetaine and carboxybetaine) construction through ring-opening reaction. Physicochemical properties of substrates were demonstrated by water contact angle measurement, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The hemocompatibility was evaluated by platelet adhesion, hemolytic, and protein adsorption. The results showed that the zwitterions immobilized PET endowed with improved resistance to nonspecific protein adsorption and platelet adhesion as well as nonhemolytic. The zwitterions with desirable hemocompatibility can be readily tailored to catheter for various biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

A Population Study of Wide-Separation Brown Dwarf Companions to Main Sequence Stars

NASA Technical Reports Server (NTRS)

Smith, Jeffrey J.

2005-01-01

Increased interest in infrared astronomy has opened the frontier to study cooler objects that shed significant light on the formation of planetary systems. Brown dwarf research provides a wealth of information useful for sorting through a myriad of proposed formation theories. Our study combines observational data from 2MASS with rigorous computer simulations to estimate the true population of long-range (greater than 1000 AU) brown dwarf companions in the solar neighborhood (less than 25 pc from Earth). Expanding on Gizis et al. (2001), we have found the margin of error in previous estimates to be significantly underestimated after we included orbit eccentricity, longitude of pericenter, angle of inclination, field star density, and primary and secondary luminosities as parameters influencing the companion systems in observational studies. We apply our simulation results to current L- and T-dwarf catalogs to provide updated estimates on the frequency of wide-separation brown dwarf companions to main sequence stars.

Long-Lag, Wide-pulse Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Norris, J. P.; Bonnell, J. T.; Kazanas, D.; Scargie, J. D.; Hakkila, J.; Giblin, T. W.

2005-01-01

The best available probe of the early phase of gamma-ray burst (GRB) jet attributes is the prompt gamma-ray emission, in which several intrinsic and extrinsic variables determine observed GRB pulse evolution, including at least: jet opening angle, profiles of Lorentz factor and matter/field density, distance of emission region from central source, and viewing angle. Bright, usually complex bursts have many narrow pulses that are difficult to model due to overlap. However, the relatively simple, long spectral lag, wide-pulse bursts may have simpler physics and are easier to model. We have analyzed the temporal and spectral behavior of wide pulses in 24 long-lag bursts from the BATSE sample, using a pulse model with two shape parameters - width and asymmetry - and the Band spectral model with three shape parameters. We find that pulses in long-lag bursts are distinguished both temporally and spectrally from those in bright bursts: the pulses in long spectral lag bursts are few in number, and approximately 100 times wider (10s of seconds), have systemtically lower peaks in nu*F(nu), harder low-energy spectra and softer high-energy spectra. These five pulse descriptors are essentially uncorrelated for our long-lag sample, suggesting that at least approximately 5 parameters are needed to model burst temporal and spectral behavior, roughly commensurate with the theoretical phase space. However, we do find that pulse width is strongly correlated with spectral lag; hence these two parameters may be viewed as mutual surrogates. The prevalence of long-lag bursts near the BATSE trigger threshold, their predominantly low nu*F(nu) spectral peaks, and relatively steep upper power-law spectral indices indicate that Swiift will detect many such bursts.

Periodic-disturbance accommodating control of the space station for asymptotic momentum management

NASA Technical Reports Server (NTRS)

Warren, Wayne; Wie, Bong

1989-01-01

Periodic maneuvering control is developed for asymptotic momentum management of control gyros used as primary actuating devices for the Space Station. The proposed controller utilizes the concepts of quaternion feedback control and periodic-disturbance accommodation to achieve oscillations about the constant torque equilibrium attitude, while minimizing the control effort required. Three-axis coupled equations of motion, written in terms of quaternions, are derived for roll/yaw controller design and stability analysis. It is shown that the quaternion feedback controller is very robust for a wide range of pitch angles. It is also shown that the proposed controller tunes the open-loop unstable vehicle to a stable oscillatory motion which minimizes the control effort needed for steady-state operations.

Creation of the precision magnetic spectrometer SCAN-3

NASA Astrophysics Data System (ADS)

Afanasiev, S. V.; Anisimov, Yu. S.; Baldin, A. A.; Berlev, A. I.; Dryablov, D. K.; Dubinchik, B. V.; Elishev, A. F.; Fateev, O. V.; Igamkulov, Z. A.; Krechetov, Yu. F.; Kudashkin, I. V.; Kuznechov, S. N.; Malakhov, A. I.; Smirnov, V. A.; Shimansky, S. S.; Kliman, J.; Matousek, V.; Gmutsa, S.; Turzo, I.; Cruceru, I.; Cruceru, M.; Constantin, F.; Niolescu, G.; Ciolacu, L.; Paraipan, M.; Vokál, S.; Vrláková, J.; Baskov, V. A.; Lebedev, A. I.; L'vov, A. I.; Pavlyuchenko, L. N.; Polyansky, V. V.; Rzhanov, E. V.; Sidorin, S. S.; Sokol, G. A.; Glavanakov, I. V.; Tabachenko, A. N.; Jomurodov, D. M.; Bekmirzaev, R. N.; Ibadov, R. M.; Sultanov, M. U.

2017-03-01

The new JINR project [1] is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article.

Additional flow field studies of the GA(W)-1 airfoil with 30-percent chord Fowler flap including slot-gap variations and cove shape modifications

NASA Technical Reports Server (NTRS)

Wentz, W. H., Jr.; Ostowari, C.

1983-01-01

Experimental measurements were made to determine the effects of slot gap opening and flap cove shape on flap and airfoil flow fields. Test model was the GA(W)-1 airfoil with 0.30c Fowler flap deflected 35 degrees. Tests were conducted with optimum, wide and narrow gaps, and with three cove shapes. Three test angles were selected, corresponding to pre-stall and post-stall conditions. Reynolds number was 2,200,000 and Mach number was 0.13. Force, surface pressure, total pressure, and split-film turbulence measurements were made. Results were compared with theory for those parameters for which theoretical values were available.

Comparative assessment of bone pose estimation using Point Cluster Technique and OpenSim.

PubMed

Lathrop, Rebecca L; Chaudhari, Ajit M W; Siston, Robert A

2011-11-01

Estimating the position of the bones from optical motion capture data is a challenge associated with human movement analysis. Bone pose estimation techniques such as the Point Cluster Technique (PCT) and simulations of movement through software packages such as OpenSim are used to minimize soft tissue artifact and estimate skeletal position; however, using different methods for analysis may produce differing kinematic results which could lead to differences in clinical interpretation such as a misclassification of normal or pathological gait. This study evaluated the differences present in knee joint kinematics as a result of calculating joint angles using various techniques. We calculated knee joint kinematics from experimental gait data using the standard PCT, the least squares approach in OpenSim applied to experimental marker data, and the least squares approach in OpenSim applied to the results of the PCT algorithm. Maximum and resultant RMS differences in knee angles were calculated between all techniques. We observed differences in flexion/extension, varus/valgus, and internal/external rotation angles between all approaches. The largest differences were between the PCT results and all results calculated using OpenSim. The RMS differences averaged nearly 5° for flexion/extension angles with maximum differences exceeding 15°. Average RMS differences were relatively small (< 1.08°) between results calculated within OpenSim, suggesting that the choice of marker weighting is not critical to the results of the least squares inverse kinematics calculations. The largest difference between techniques appeared to be a constant offset between the PCT and all OpenSim results, which may be due to differences in the definition of anatomical reference frames, scaling of musculoskeletal models, and/or placement of virtual markers within OpenSim. Different methods for data analysis can produce largely different kinematic results, which could lead to the misclassification of normal or pathological gait. Improved techniques to allow non-uniform scaling of generic models to more accurately reflect subject-specific bone geometries and anatomical reference frames may reduce differences between bone pose estimation techniques and allow for comparison across gait analysis platforms.

Linkage analysis excludes the glaucoma locus on 1q from involvement in autosomal dominant glaucoma with iris hypoplasia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heon, E.; Sheth, B.P.; Kalenak, J.W.

1994-09-01

Genetic factors have been implicated in a variety of types of glaucoma including primary open-angle glaucoma, infantile glaucoma, pigmentary glaucoma, and juvenile open-angle glaucoma. We previously mapped the disease-causing gene for one type of juvenile open angle glaucoma to chromosome 1q21-31. Weatherill and Hart (1969) and Pearce (1983) each noted the association of iris hypoplasia and early-onset autosomal dominant glaucoma. We recently had the opportunity to study a large family (12 affected members) with this phenotype. Affected individuals developed glaucoma at an average age of 30 years. These patients also have a strikingly underdeveloped iris stroma which causes a peculiarmore » eye color. Linkage analysis was able to completely exclude the 1q glaucoma locus from involvement in the disorder that affects this family. A complete clinical description of the family and linkage results at additional candidate loci will be presented.« less

iStent trabecular micro-bypass stent for open-angle glaucoma

PubMed Central

Le, Kim; Saheb, Hady

2014-01-01

Trabecular micro-bypass stents, commonly known as iStents, are micro-invasive glaucoma surgery (MIGS) devices used to treat open-angle glaucoma. Like other MIGS procedures that enhance trabecular outflow, the iStent lowers intraocular pressure (IOP) by creating a direct channel between the anterior chamber and Schlemm’s canal. iStents are typically implanted at the time of phacoemulsification for patients with open-angle glaucoma and visually significant cataracts. This review summarizes the published data regarding the efficacy, safety, and cost considerations of trabecular micro-bypass stents. Most studies found statistically significant reductions in mean IOP and ocular medication use after combined phacoemulsification with single or double iStent implantation. The devices were found to be very safe, with a safety profile similar to that of cataract surgery. Complications were infrequent, with the most common complications being temporary stent obstruction or malposition, which resolved with observation or secondary procedures. Future studies are needed to evaluate long-term outcomes, patient satisfaction, cost effectiveness, and expanded indications. PMID:25284980

Angle stability and outflow in dual blade ab interno trabeculectomy with active versus passive chamber management

PubMed Central

Wang, Chao; Dang, Yalong; Waxman, Susannah; Xia, Xiaobo; Weinreb, Robert N.

2017-01-01

Purpose To compare intraoperative angle stability and postoperative outflow of two ab interno trabeculectomy devices that excise the trabecular meshwork with or without active aspiration and irrigation. We hypothesized that anterior segment optical coherence tomography (AS-OCT) allows for a quantitative comparison of intraoperative angle stability in a microincisional glaucoma surgery (MIGS) pig eye training model. Methods Twelve freshly enucleated porcine eyes were measured with AS-OCT at baseline, at the beginning of the procedure and at its conclusion to determine the anterior chamber depth (ACD) and the nasal angle α in degrees. The right and left eye of pairs were randomly assigned to an active dual blade goniectome (aDBG) and a passive dual blade goniectome (pDBG) group, respectively. The aDBG had irrigation and aspiration ports while the pDBG required surgery under viscoelastic. We performed the procedures using our MIGS training system with a standard, motorized ophthalmic operating microscope. We estimated outflow by obtaining canalograms with fluorescent spheres. Results In aDBG, the nasal angle remained wide open during the procedure at above 90° and did not change towards the end (100±10%, p = 0.9). In contrast, in pDBG, ACD decreased by 51±19% to 21% below baseline (p<0.01) while the angle progressively narrowed by 40±12% (p<0.001). Canalograms showed a similar extent of access to the outflow tract with the aDBG and the pDBG (p = 0.513). The average increase for the aDBG in the superonasal and inferonasal quadrants was between 27 to 31% and for the pDBG between 15 to 18%. Conclusion AS-OCT demonstrated that active irrigation and aspiration improved anterior chamber maintenance and ease of handling with the aDBG in this MIGS training model. The immediate postoperative outflow was equally good with both devices. PMID:28486513

Wide-angle seismic recording from the 2002 Georgia Basin Geohazards Initiative, northwestern Washington and British Columbia

USGS Publications Warehouse

Brocher, Thomas M.; Pratt, Thomas L.; Spence, George D.; Riedel, Michael; Hyndman, Roy D.

2003-01-01

This report describes the acquisition and processing of shallow-crustal wide-angle seismicreflection and refraction data obtained during a collaborative study in the Georgia Strait, western Washington and southwestern British Columbia. The study, the 2002 Georgia Strait Geohazards Initiative, was conducted in May 2002 by the Pacific Geoscience Centre, the U.S. Geological Survey, and the University of Victoria. The wide-angle recordings were designed to image shallow crustal faults and Cenozoic sedimentary basins crossing the International Border in southern Georgia basin and to add to existing wide-angle recordings there made during the 1998 SHIPS experiment. We recorded, at wide-angle, 800 km of shallow penetration multichannel seismic-reflection profiles acquired by the Canadian Coast Guard Ship (CCGS) Tully using an air gun with a volume of 1.967 liters (120 cu. in.). Prior to this reflection survey, we deployed 48 Refteks onshore to record the airgun signals at wide offsets. Three components of an oriented, 4.5 Hz seismometer were digitally recorded at all stations. Nearly 160,300 individual air gun shots were recorded along 180 short seismic reflection lines. In this report, we illustrate the wide-angle profiles acquired using the CCGS Tully, describe the land recording of the air gun signals, and summarize the processing of the land recorder data into common-receiver gathers. We also describe the format and content of the archival tapes containing the SEGY-formated, common-receiver gathers for the Reftek data. Data quality is variable but the experiment provided useful data from 42 of the 48 stations deployed. Three-fourths of all stations yielded useful first-arrivals to source-receiver offsets beyond 10 km: the average maximum source-receiver offset for first arrivals was 17 km. Six stations yielded no useful data and useful firstarrivals were limited to offsets less than 10 km at five stations. We separately archived our recordings of 86 local and regional earthquakes ranging in magnitude from 0.2 to 4.3 and 16 teleseisms ranging in magnitude 5.5 to 6.5.

Early Clinical Results of a Novel Ab Interno Gel Stent for the Surgical Treatment of Open-angle Glaucoma.

PubMed

Sheybani, Arsham; Dick, H Burkhard; Ahmed, Iqbal I K

2016-07-01

To evaluate the intraocular pressure (IOP) lowering effect of the XEN140 microfistula gel stent implant for the surgical treatment of open-angle glaucoma. Forty-nine eyes of 49 patients with an IOP>18 mm Hg and ≤35 mm Hg were studied in a prospective nonrandomized multicenter cohort trial of the surgical implantation of the XEN140 implant in patients with open-angle glaucoma. Complete success was defined as a postoperative IOP≤18 mm Hg with ≥20% reduction in IOP at 12 months without any glaucoma medications. Failure was defined as vision loss of light perceptions vision or worse, need for additional glaucoma surgery, or <20% reduction of IOP from baseline. The average age was 64.3 (28.1 to 86.9) years old. Twenty-one eyes had prior failed trabeculectomy with mitomycin C surgery. IOP at 12 months decreased from a mean of 23.1 (±4.1) mm Hg to 14.7 (±3.7) mm Hg for a 36.4% reduction in IOP from baseline. The number of patients at 12 months who achieved an IOP≤18 mm Hg and ≥20% reduction in IOP was 40 (89%). The number of patients who achieved an IOP≤18 mm Hg and ≥20% reduction in IOP without antiglaucoma medications was 18 (40%). The XEN140 gel stent lowers IOP with few complications when implanted for the surgical treatment of open-angle glaucoma.

Master Volunteer Life Cycle: A Wide Angle Lens on the Volunteer Experience

ERIC Educational Resources Information Center

Strauss, Andrea Lorek; Rager, Amy

2017-01-01

Extension master volunteer programs, such as master naturalist and master gardener, often focus heavily on volunteer education. The model presented here describes the full life cycle of a master volunteer's experience in the program, putting education in the context of other essential program components. By zooming out to a wide-angle view of the…

Juxtacanalicular tissue in pigmentary and primary open angle glaucoma. The hydrodynamic role of pigment and other constituents.

PubMed

Murphy, C G; Johnson, M; Alvarado, J A

1992-12-01

We tested the hypothesis that obstruction of the juxtacanalicular tissues, by melanin granules in pigmentary glaucoma and by other impermeable material in primary open angle glaucoma, leads to the development of a chronic glaucomatous condition. The distribution and concentration of melanin and other impermeable materials in the juxtacanalicular tissues and elsewhere in the trabecular meshwork was determined in 13 specimens. Six specimens were from patients with pigmentary glaucoma, two from patients with pigment dispersion syndrome, and three from patients with primary open angle glaucoma, as well as two from normal subjects. The effect of these materials on flow resistance was estimated using two hydrodynamic models. In model A, the electron-lucent spaces of the juxtacanalicular tissue were assumed to be open spaces, while in model B, these spaces and spaces filled with ground substance were assumed to be gel filled. In pigmentary glaucoma, 3.5% of the pigment was found in the juxtacanalicular tissue, while 96.5% was found in the corneoscleral and uveoscleral tissues. Permeabilities calculated according to model A were much higher than those expected from estimates of outflow facility in all groups, in agreement with the previous report of Ethier et al. The gel-filled spaces available for fluid flow, as determined by model B, showed no statistically demonstrable differences (pigmentary glaucoma, 32.9%; primary open angle glaucoma, 36.6%; pigment dispersion syndrome, 43.4%; normal, 44.1%). Furthermore, the amount of pigment present in the juxtacanalicular tissue was determined to have a negligible influence on permeability. Thus, the development of the chronic glaucomatous condition cannot be directly attributed to pigment accumulation in the juxtacanalicular tissue in pigmentary glaucoma.

Structure of gamma-ray burst jets: intrinsic versus apparent properties

NASA Astrophysics Data System (ADS)

Salafia, O. S.; Ghisellini, G.; Pescalli, A.; Ghirlanda, G.; Nappo, F.

2015-07-01

With this paper we introduce the concept of apparent structure of a gamma-ray burst (GRB) jet, as opposed to its intrinsic structure. The latter is customarily defined specifying the functions ɛ(θ) (the energy emitted per jet unit solid angle) and Γ(θ) (the Lorentz factor of the emitting material); the apparent structure is instead defined by us as the isotropic equivalent energy Eiso(θv) as a function of the viewing angle θv. We show how to predict the apparent structure of a jet given its intrinsic structure. We find that a Gaussian intrinsic structure yields a power-law apparent structure: this opens a new viewpoint on the Gaussian (which can be understood as a proxy for a realistic narrow, well-collimated jet structure) as a possible candidate for a quasi-universal GRB jet structure. We show that such a model (a) is consistent with recent constraints on the observed luminosity function of GRBs; (b) implies fewer orphan afterglows with respect to the standard uniform model; (c) can break out the progenitor star (in the collapsar scenario) without wasting an unreasonable amount of energy; (d) is compatible with the explanation of the Amati correlation as a viewing angle effect; (e) can be very standard in energy content, and still yield a very wide range of observed isotropic equivalent energies.

Modelling of the outburst on July 29th , 2015 observed with OSIRIS in the southern hemisphere of comet 67P/Churyumov-Gerasimenko

NASA Astrophysics Data System (ADS)

Gicquel, Adeline; Vincent, Jean-Baptiste; Sierks, Holger; Rose, Martin; Agarwal, Jessica; Deller, Jakob; Guettler, Carsten; Hoefner, Sebastian; Hofmann, Marc; Hu, Xuanyu; Kovacs, Gabor; Oklay Vincent, Nilda; Shi, Xian; Tubiana, Cecilia; Barbieri, Cesare; Lamy, Phylippe; Rodrigo, Rafael; Koschny, Detlef; Rickman, Hans; OSIRIS Team

2016-10-01

Images of the nucleus and the coma (gas and dust) of comet 67P/Churyumov- Gerasimenko have been acquired by the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras system since March 2014 using both the wide angle camera (WAC) and the narrow angle camera (NAC). We are using the NAC camera to study the bright outburst observed on July 29th, 2015 in the southern hemisphere. The NAC camera's wavelength ranges between 250-1000 nm with a combination of 12 filters. The high spatial resolution is needed to localize the source point of the outburst on the surface of the nucleus. At the time of the observations, the heliocentric distance was 1.25AU and the distance between the spacecraft and the comet was 126 km. We aim to understand the physics leading to such outgassing: Is the jet associated to the outbursts controlled by the micro-topography? Or by ice suddenly exposed? We are using the Direct Simulation Monte Carlo (DSMC) method to study the gas flow close to the nucleus. The goal of the DSMC code is to reproduce the opening angle of the jet, and constrain the outgassing ratio between outburst source and local region. The results of this model will be compared to the images obtained with the NAC camera.

Percutaneous versus traditional and paraspinal posterior open approaches for treatment of thoracolumbar fractures without neurologic deficit: a meta-analysis.

PubMed

Sun, Xiang-Yao; Zhang, Xi-Nuo; Hai, Yong

2017-05-01

This study evaluated differences in outcome variables between percutaneous, traditional, and paraspinal posterior open approaches for traumatic thoracolumbar fractures without neurologic deficit. A systematic review of PubMed, Cochrane, and Embase was performed. In this meta-analysis, we conducted online searches of PubMed, Cochrane, Embase using the search terms "thoracolumbar fractures", "lumbar fractures", ''percutaneous'', "minimally invasive", ''open", "traditional", "posterior", "conventional", "pedicle screw", "sextant", and "clinical trial". The analysis was performed on individual patient data from all the studies that met the selection criteria. Clinical outcomes were expressed as risk difference for dichotomous outcomes and mean difference for continuous outcomes with 95 % confidence interval. Heterogeneity was assessed using the χ 2 test and I 2 statistics. There were 4 randomized controlled trials and 14 observational articles included in this analysis. Percutaneous approach was associated with better ODI score, less Cobb angle correction, less Cobb angle correction loss, less postoperative VBA correction, and lower infection rate compared with open approach. Percutaneous approach was also associated with shorter operative duration, longer intraoperative fluoroscopy, less postoperative VAS, and postoperative VBH% in comparison with traditional open approach. No significant difference was found in Cobb angle correction, postoperative VBA, VBA correction loss, Postoperative VBH%, VBH correction loss, and pedicle screw misplacement between percutaneous approach and open approach. There was no significant difference in operative duration, intraoperative fluoroscopy, postoperative VAS, and postoperative VBH% between percutaneous approach and paraspianl approach. The functional and the radiological outcome of percutaneous approach would be better than open approach in the long term. Although trans-muscular spatium approach belonged to open fixation methods, it was strictly defined as less invasive approach, which provided less injury to the paraspinal muscles and better reposition effect.

Quantitative angle-insensitive flow measurement using relative standard deviation OCT.

PubMed

Zhu, Jiang; Zhang, Buyun; Qi, Li; Wang, Ling; Yang, Qiang; Zhu, Zhuqing; Huo, Tiancheng; Chen, Zhongping

2017-10-30

Incorporating different data processing methods, optical coherence tomography (OCT) has the ability for high-resolution angiography and quantitative flow velocity measurements. However, OCT angiography cannot provide quantitative information of flow velocities, and the velocity measurement based on Doppler OCT requires the determination of Doppler angles, which is a challenge in a complex vascular network. In this study, we report on a relative standard deviation OCT (RSD-OCT) method which provides both vascular network mapping and quantitative information for flow velocities within a wide range of Doppler angles. The RSD values are angle-insensitive within a wide range of angles, and a nearly linear relationship was found between the RSD values and the flow velocities. The RSD-OCT measurement in a rat cortex shows that it can quantify the blood flow velocities as well as map the vascular network in vivo .

Quantitative angle-insensitive flow measurement using relative standard deviation OCT

NASA Astrophysics Data System (ADS)

Zhu, Jiang; Zhang, Buyun; Qi, Li; Wang, Ling; Yang, Qiang; Zhu, Zhuqing; Huo, Tiancheng; Chen, Zhongping

2017-10-01

Incorporating different data processing methods, optical coherence tomography (OCT) has the ability for high-resolution angiography and quantitative flow velocity measurements. However, OCT angiography cannot provide quantitative information of flow velocities, and the velocity measurement based on Doppler OCT requires the determination of Doppler angles, which is a challenge in a complex vascular network. In this study, we report on a relative standard deviation OCT (RSD-OCT) method which provides both vascular network mapping and quantitative information for flow velocities within a wide range of Doppler angles. The RSD values are angle-insensitive within a wide range of angles, and a nearly linear relationship was found between the RSD values and the flow velocities. The RSD-OCT measurement in a rat cortex shows that it can quantify the blood flow velocities as well as map the vascular network in vivo.

Development of a synthetic aperture radar design approach for wide-swath implementation

NASA Technical Reports Server (NTRS)

Jean, B. R.

1981-01-01

The first phase of a study program to develop an advanced synthetic aperture radar design concept is presented. Attributes of particular importance for the system design include wide swath coverage, reduced power requirements, and versatility in the selection of frequency, polarization and incident angle. The multiple beam configuration provides imaging at a nearly constant angle of incidence and offers the potential of realizing a wide range of the attributes desired for an orbital imaging radar for Earth resources applications.

Daytime Water Detection Based on Sky Reflections

NASA Technical Reports Server (NTRS)

Rankin, Arturo L.; Matthies, Larry H.; Bellutta, Paolo

2011-01-01

Robust water detection is a critical perception requirement for unmanned ground vehicle (UGV) autonomous navigation. This is particularly true in wide-open areas where water can collect in naturally occurring terrain depressions during periods of heavy precipitation and form large water bodies. One of the properties of water useful for detecting it is that its surface acts as a horizontal mirror at large incidence angles. Water bodies can be indirectly detected by detecting reflections of the sky below the horizon in color imagery. The Jet Propulsion Laboratory (JPL) has implemented a water detector based on sky reflections that geometrically locates the pixel in the sky that is reflecting on a candidate water pixel on the ground and predicts if the ground pixel is water based on color similarity and local terrain features. This software detects water bodies in wide-open areas on cross-country terrain at mid- to far-range using imagery acquired from a forward-looking stereo pair of color cameras mounted on a terrestrial UGV. In three test sequences approaching a pond under a clear, overcast, and cloudy sky, the true positive detection rate was 100% when the UGV was beyond 7 meters of the water's leading edge and the largest false positive detection rate was 0.58%. The sky reflection based water detector has been integrated on an experimental unmanned vehicle and field tested at Ft. Indiantown Gap, PA, USA.

Glaucoma and clinical characteristics in Vietnamese Americans.

PubMed

Peng, Pai-Huei; Manivanh, Richard; Nguyen, Ngoc; Weinreb, Robert N; Lin, Shan C

2011-08-01

To assess the proportions of glaucoma types and clinical characteristics in Vietnamese Americans in a single-center, retrospective study. Medical charts of Vietnamese-American patients who visited a single private practice in Northern California from 1998-2007 were reviewed. The main outcome measures included the distribution and characteristics of glaucoma types, and clinical parameters associated with the presence of various glaucomas. Data from 2247 patients aged 18-98 years were reviewed. Glaucoma was determined for 305 patients (13.6%). Among this group, 54.8% had primary open-angle glaucoma (POAG), 26.9% had primary angle-closure glaucoma (PACG), 13.4% had mixed mechanism glaucoma (MMG), and 4.9% had secondary glaucoma. In the MMG group (41 patients), 27 patients who initially had open angles developed narrow angles and underwent laser peripheral iridotomy (LPI) with a mean follow up of 6.4 years from the time of iridotomy. The other 13 patients had glaucoma progression with open angles after LPI. One POAG patient had neovascular glaucoma due to retinal vein occlusion several years later. Compared to the PACG group, the MMG group had significantly lower baseline intraocular pressure (25.0 vs. 20.2 mmHg, p = 0.007) but with no difference in biometry. POAG is the major type of glaucoma in this clinic-based Vietnamese population. However, Vietnamese appear to have a relatively higher proportion of PACG than Caucasians and those of African descent. It is recommended that gonioscopy be part of the regular eye check-up for adult Vietnamese patients.

Edge contact angle and modified Kelvin equation for condensation in open pores.

PubMed

Malijevský, Alexandr; Parry, Andrew O; Pospíšil, Martin

2017-08-01

We consider capillary condensation transitions occurring in open slits of width L and finite height H immersed in a reservoir of vapor. In this case the pressure at which condensation occurs is closer to saturation compared to that occurring in an infinite slit (H=∞) due to the presence of two menisci that are pinned near the open ends. Using macroscopic arguments, we derive a modified Kelvin equation for the pressure p_{cc}(L;H) at which condensation occurs and show that the two menisci are characterized by an edge contact angle θ_{e} that is always larger than the equilibrium contact angle θ, only equal to it in the limit of macroscopic H. For walls that are completely wet (θ=0) the edge contact angle depends only on the aspect ratio of the capillary and is well described by θ_{e}≈sqrt[πL/2H] for large H. Similar results apply for condensation in cylindrical pores of finite length. We test these predictions against numerical results obtained using a microscopic density-functional model where the presence of an edge contact angle characterizing the shape of the menisci is clearly visible from the density profiles. Below the wetting temperature T_{w} we find very good agreement for slit pores of widths of just a few tens of molecular diameters, while above T_{w} the modified Kelvin equation only becomes accurate for much larger systems.

Open top culverts as an alternative drainage system to minimize ecological effects in earth roads.

NASA Astrophysics Data System (ADS)

García, Jose L.; Elorrieta, Jose; Robredo, Jose C.; García, Ricardo; García, Fernando; Gimenez, Martin C.

2013-04-01

During the last fifteen years a research team from School of Forestry at the Technical University of Madrid (Spain) has developed several competitive research projects regarding forest roads and open top culverts. A first approach was established with a prototype of 7 meters length in a hydraulic channel at the laboratory determining main parameters of different open top culverts in relation to different sizes of gravels and the self washing properties relationship with different slopes up to 8 %. The curves obtained may help to properly install these drainage systems avoiding maintenance costs. In addition more targeted pilot studies were developed in different forest earth roads in center and north Spain. The construction of the stations under study was financed by the U.P.M and the R&D National Plan. The main outcomes relates the low variation of humidity in a 20 m. wide range at both sides of the open top culverts and several considerations relating the angle of installation, the spacing of such drainage systems and the benefits against rilling along the roads. Also the erosion produced downhill was established and some construction methods to avoid adverse ecological effects. The diffusion of results includes congresses and a small booklet with a great acceptance in forestry services. Also a patent (ES 2 262 437) of an advanced model has been registered.

Development of wide-angle 2D light scattering static cytometry

NASA Astrophysics Data System (ADS)

Xie, Linyan; Liu, Qiao; Shao, Changshun; Su, Xuantao

2016-10-01

We have recently developed a 2D light scattering static cytometer for cellular analysis in a label-free manner, which measures side scatter (SSC) light in the polar angular range from 79 to 101 degrees. Compared with conventional flow cytometry, our cytometric technique requires no fluorescent labeling of the cells, and static cytometry measurements can be performed without flow control. In this paper we present an improved label-free static cytometer that can obtain 2D light scattering patterns in a wider angular range. By illuminating the static microspheres on chip with a scanning optical fiber, wide-angle 2D light scattering patterns of single standard microspheres with a mean diameter of 3.87 μm are obtained. The 2D patterns of 3.87 μm microspheres contain both large-angle forward scatter (FSC) and SSC light in the polar angular range from 40 to 100 degrees, approximately. Experimental 2D patterns of 3.87 μm microspheres are in good agreement with Mie theory simulated ones. The wide-angle light scattering measurements may provide a better resolution for particle analysis as compared with the SSC measurements. Two dimensional light scattering patterns of HL-60 human acute leukemia cells are obtained by using our static cytometer. Compared with SSC 2D light scattering patterns, wide-angle 2D patterns contain richer information of the HL-60 cells. The obtaining of 2D light scattering patterns in a wide angular range could help to enhance the capabilities of our label-free static cytometry for cell analysis.

[The effectiveness of endonasal electrophoresis of neuroprotective agents used in the rehabilitative treatment of the patients presenting with primary open angle glaucoma].

PubMed

Nazarova, G A; Konchugova, T V; Iurova, O V; Sichinava, N V; Turova, E A; Rassulova, M A; Morozova, N E

2013-01-01

The objective of the present study was to estimate the effectiveness of the peptide drug cortexin used to treat primary open angle glaucoma. It was shown that endonasal electrophoresis of cortexin resulted in more pronounced positive changes in the dynamics of clinical, functional, perimetric, and electrophysiological characteristics compared with intramuscular administration of the same drug to the patients of the control group. This difference was apparent both immediately after the termination of the treatment and during the long-term follow-up.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yanagawa, T.; Sakagami, H.; Nagatomo, H.

In inertial confinement fusion, the implosion process is important in forming a high-density plasma core. In the case of a fast ignition scheme using a cone-guided target, the fuel target is imploded with a cone inserted. This scheme is advantageous for efficiently heating the imploded fuel core; however, asymmetric implosion is essentially inevitable. Moreover, the effect of cone position and opening angle on implosion also becomes critical. Focusing on these problems, the effect of the asymmetric implosion, the initial position, and the opening angle on the compression rate of the fuel is investigated using a three-dimensional pure hydrodynamic code.

[Thinking about the present primary open angle glaucoma early diagnosis concepts and methods].

PubMed

Ren, Zeqin

2014-05-01

Early diagnosis of primary open-angle glaucoma has not been clear and consistent in concepts and methods. At present, according to the pathophysiology process of optic nerve damage and its detection technology, early diagnosis on the concept still belongs to the early clinical diagnosis instead of preclinical diagnosis, and on the method depends on the fundus as morphological index combined with the visual field as functional index. The direction of early clinical diagnosis mainly lies in exploring more effective diagnosis index, rather than blindly adopt new diagnostic technology.

Earhart Propeller in Saturn A Ring

NASA Image and Video Library

2017-03-30

The propeller informally named "Earhart" is seen in this view from NASA's Cassini spacecraft at much higher resolution than ever before. This view, obtained on March 22, 2017, is the second time Cassini has deliberately targeted an individual propeller for close-up viewing during its ring-grazing orbits, after its images of Santos-Dumont (PIA21433) a month earlier. The biggest known propeller, informally named "Bleriot," is slated for the third and final propeller close-up in April 2017. Propellers are disturbances in the ring caused by a central moonlet. The moonlet itself would be a few pixels wide in this view, but it is difficult to distinguish from (and may be obscured by) the disturbed ring material that surrounds it. (See PIA20525 for more info on propellers.) The detailed structure of the Earhart propeller, as seen here, differs from that of Santos-Dumont. It is not clear whether these differences have to do with intrinsic differences between Earhart and Santos-Dumont, or whether they have to do with different viewing angles or differences in where the propellers were imaged in their orbits around Saturn. Earhart is situated very close to the 200-mile-wide (320-kilometer-wide) Encke Gap, which is held open by the much larger moon Pan. In this view, half of the Encke Gap is visible as the dark region at right. The gap and the propeller are a study in contrasts. The propeller is nothing more than Earhart's attempt to open a gap like Encke using its gravity. However, Earhart's attempt is thwarted by the mass of the ring, which fills in the nascent gap before it can extend very far. Pan is a few thousand times more massive than Earhart, which enables it to maintain a gap that extends all the way around the ring. To the left of the propeller are wave features in the rings caused by the moons Pandora, Prometheus and Pan. The visible-light image was acquired by the Cassini narrow-angle camera at a distance of 69,183 miles (111,340 kilometers) from the propeller feature. Image scale is 0.4 mile (670 meters) per pixel in the radial, or outward-from-Saturn, direction. The view looks toward the sunlit side of the rings. https://photojournal.jpl.nasa.gov/catalog/PIA21437

Bite angle effects of diphosphines in C-C and C-X bond forming cross coupling reactions.

PubMed

Birkholz, Mandy-Nicole; Freixa, Zoraida; van Leeuwen, Piet W N M

2009-04-01

Catalytic reactions of C-C and C-X bond formation are discussed in this critical review with particular emphasis on cross coupling reactions catalyzed by palladium and wide bite angle bidentate diphosphine ligands. Especially those studies have been collected that allow comparison of the ligand bite angles for the selected ligands: dppp, BINAP, dppf, DPEphos and Xantphos. Similarities with hydrocyanation and CO/ethene/MeOH reactions have been highlighted, while rhodium hydroformylation has been mentioned as a contrasting example, in which predictability is high and steric and electronic effects follow smooth trends. In palladium catalysis wide bite angles and bulkiness of the ligands facilitate generally the reductive elimination thus giving more efficient cross coupling catalysis (174 references).

Argon laser peripheral iridoplasty for angle-closure glaucoma in sibilings with weill-marchesani syndrome.

PubMed

Ritch, R; Solomon, L D

1992-01-01

A patient with Weill-Marchesani syndrome and angle-closure glaucoma had persistent appositional closure after laser iridotomy that was unrelieved by topical application of either miotic or cycloplegic agents. Argon laser peripheral iridoplasty successfully opened the angle. The patient's sister also had Weill-Marchesani syndrome and angle closure unrelieved by laser iridotomy. Angle closure in Weill-Marchesani syndrome and the response to laser iridotomy and treatment with either miotic or cycloplegic agents may be complex and depends on the relative proportion of pupillary block as a mechanism underlying the angle closure, the functional status of the zonular apparatus, and the degree of angle crowding by the peripheral iris in the presence or absence of peripheral anterior synechiae.

A three-dimensional wide-angle BPM for optical waveguide structures.

PubMed

Ma, Changbao; Van Keuren, Edward

2007-01-22

Algorithms for effective modeling of optical propagation in three- dimensional waveguide structures are critical for the design of photonic devices. We present a three-dimensional (3-D) wide-angle beam propagation method (WA-BPM) using Hoekstra's scheme. A sparse matrix algebraic equation is formed and solved using iterative methods. The applicability, accuracy and effectiveness of our method are demonstrated by applying it to simulations of wide-angle beam propagation, along with a technique for shifting the simulation window to reduce the dimension of the numerical equation and a threshold technique to further ensure its convergence. These techniques can ensure the implementation of iterative methods for waveguide structures by relaxing the convergence problem, which will further enable us to develop higher-order 3-D WA-BPMs based on Padé approximant operators.

A three-dimensional wide-angle BPM for optical waveguide structures

NASA Astrophysics Data System (ADS)

Ma, Changbao; van Keuren, Edward

2007-01-01

Algorithms for effective modeling of optical propagation in three- dimensional waveguide structures are critical for the design of photonic devices. We present a three-dimensional (3-D) wide-angle beam propagation method (WA-BPM) using Hoekstra’s scheme. A sparse matrix algebraic equation is formed and solved using iterative methods. The applicability, accuracy and effectiveness of our method are demonstrated by applying it to simulations of wide-angle beam propagation, along with a technique for shifting the simulation window to reduce the dimension of the numerical equation and a threshold technique to further ensure its convergence. These techniques can ensure the implementation of iterative methods for waveguide structures by relaxing the convergence problem, which will further enable us to develop higher-order 3-D WA-BPMs based on Padé approximant operators.

Outer planets mission television subsystem optics study

NASA Technical Reports Server (NTRS)

1972-01-01

An optics study was performed to establish a candidate optical system design for the proposed NASA Mariner Jupiter/Saturn 77 mission. The study was performed over the 6-month period from January through June 1972. The candidate optical system contains both a wide angle (A) and a narrow angle (B) lens. An additional feature is a transfer mirror mechanism that allows image transfer from the B lens to the vidicon initially used for the A lens. This feature adds an operational redundancy to the optical system in allowing for narrow angle viewing if the narrow angle vidicon were to fail. In this failure mode, photography in the wide angle mode would be discontinued. The structure of the candidate system consists mainly of aluminum with substructures of Invar for athermalization. The total optical system weighs (excluding vidicons) approximately 30 pounds and has overall dimensions of 26.6 by 19.5 by 12.3 inches.

Equilibrium configurations of the conducting liquid surface in a nonuniform electric field

NASA Astrophysics Data System (ADS)

Zubarev, N. M.; Zubareva, O. V.

2011-01-01

Possible equilibrium configurations of the free surface of a conducting liquid deformed by a nonuniform external electric field are investigated. The liquid rests on an electrode that has the shape of a dihedral angle formed by two intersecting equipotential half-planes (conducting wedge). It is assumed that the problem has plane symmetry: the surface is invariant under shift along the edge of the dihedral angle. A one-parametric family of exact solutions for the shape of the surface is found in which the opening angle of the region above the wedge serves as a parameter. The solutions are valid when the pressure difference between the inside and outside of the liquid is zero. For an arbitrary pressure difference, approximate solutions to the problem are constructed and it is demonstrated the approximation error is small. It is found that, when the potential difference exceeds a certain threshold value, equilibrium solutions are absent. In this case, the region occupied by the liquid disintegrates, the disintegration scenario depending on the opening angle.

Detection of primary angle closure using anterior segment optical coherence tomography in Asian eyes.

PubMed

Nolan, Winifred P; See, Jovina L; Chew, Paul T K; Friedman, David S; Smith, Scott D; Radhakrishnan, Sunita; Zheng, Ce; Foster, Paul J; Aung, Tin

2007-01-01

To evaluate noncontact anterior segment optical coherence technology (AS-OCT) as a qualitative method of imaging the anterior chamber angle and to determine its ability to detect primary angle closure when compared with gonioscopy in Asian subjects. Prospective observational case series. Two hundred three subjects were recruited from glaucoma clinics in Singapore with diagnoses of primary angle closure, primary open-angle glaucoma, ocular hypertension, or cataract. Both eyes (if eligible) of each patient were included in the study. Exclusion criteria were pseudophakia or previous glaucoma surgery. Images of the nasal, temporal, and inferior angles were obtained with AS-OCT in dark and then light conditions. Gonioscopic angle width was graded using the Spaeth classification for each quadrant in low lighting conditions. Angle closure was defined by AS-OCT as contact between the peripheral iris and angle wall anterior to the scleral spur and by gonioscopy as a Spaeth grade of 0 degree (posterior trabecular meshwork not visible). Comparison of the 2 methods in detecting angle closure was done by eye and by individual. Sensitivities and specificities of AS-OCT were calculated using gonioscopy as the reference standard. Complete data were available for 342 eyes of 200 patients. Of the patients, 70.9% had a clinical diagnosis of treated or untreated primary angle closure. Angle closure in > or =1 quadrants was detected by AS-OCT in 142 (71%) patients (228 [66.7%] eyes) and by gonioscopy in 99 (49.5%) patients (152 [44.4%] eyes). The inferior angle was closed more frequently than the nasal or temporal quadrants using both AS-OCT and gonioscopy. When performed under dark conditions, AS-OCT identified 98% of those subjects found to have angle closure on gonioscopy (95% confidence interval [CI], 92.2-99.6) and led to the characterization of 44.6% of those found to have open angles on gonioscopy to have angle closure as well. With gonioscopy as the reference standard, specificity of AS-OCT in the dark was 55.4% (95% CI, 45.2-65.2) for detecting individuals with angle closure. Anterior segment OCT is a rapid noncontact method of imaging angle structures. It is highly sensitive in detecting angle closure when compared with gonioscopy. More persons are found to have closed angles with AS-OCT than with gonioscopy.

Ocular Pseudoexfoliation and Cardiovascular Disease: A National Cross-Section Comparison Study

PubMed Central

French, Dustin D; Margo, Curtis E; Harman, Lynn E

2012-01-01

Background: Pseudoexfoliation is a systemic disorder characterized by the deposition of extracellular matrix material. The microfibrillar material that gives rise to the condition is visible clinically in the anterior segment of the eye, and is also found in other tissues, including blood vessels, skin, gallbladder, kidneys, lungs, and heart. Aims: The present study aims to determine whether ocular pseudoexfoliation is associated with selected cardiovascular diseases. Materials and Methods: A cross-section comparison study was conducted with the help of the Veterans Health Administration databases, using the International Classification of Diseases, Ninth revision, Clinical Modification for pseudoexfoliation of lens capsule and pseudoexfoliation glaucoma. Selected cardiovascular diseases and risk factors for cardiovascular disease were identified using the appropriate medical codes. Patients with primary open-angle glaucoma, chronic sinusitis, and benign prostatic hyperplasia served as the comparison groups. A logistic regression model was used to control for age, gender, race, and major cardiovascular risk factors. Results: There were 6,046 case patients with pseudoexfoliation; approximately half were diagnosed with pseudoexfoliation glaucoma. Various stages of ischemic heart disease, cardiomyopathy, and aortic aneurysm were significantly associated with ocular pseudoexfoliation, after controlling for age, gender, race, and major cardiovascular risk factors. Associations, in general, were less demonstrable relative to the primary open-angle glaucoma comparison group. Conclusion: Associations of ocular pseudoexfoliation with cardiovascular diseases were generally fewer and less pronounced when compared to patients with primary open-angle glaucoma. These results add to the results of earlier studies, which suggest that open-angle glaucoma itself might be a risk factor for certain cardiovascular disorders. PMID:23112968

Comparison between visual field defect in pigmentary glaucoma and primary open-angle glaucoma.

PubMed

Nilforushan, Naveed; Yadgari, Maryam; Jazayeri, Anisalsadat

2016-10-01

To compare visual field defect patterns between pigmentary glaucoma and primary open-angle glaucoma. Retrospective, comparative study. Patients with diagnosis of primary open-angle glaucoma (POAG) and pigmentary glaucoma (PG) in mild to moderate stages were enrolled in this study. Each of the 52 point locations in total and pattern deviation plot (excluding 2 points adjacent to blind spot) of 24-2 Humphrey visual field as well as six predetermined sectors were compared using SPSS software version 20. Comparisons between 2 groups were performed with the Student t test for continuous variables and the Chi-square test for categorical variables. Thirty-eight eyes of 24 patients with a mean age of 66.26 ± 11 years (range 48-81 years) in the POAG group and 36 eyes of 22 patients with a mean age of 50.52 ± 11 years (range 36-69 years) in the PG group were studied. (P = 0.00). More deviation was detected in points 1, 3, 4, and 32 in total deviation (P = 0.03, P = 0.015, P = 0.018, P = 0.023) and in points 3, 4, and 32 in pattern deviation (P = 0.015, P = 0.049, P = 0.030) in the POAG group, which are the temporal parts of the field. It seems that the temporal area of the visual field in primary open-angle glaucoma is more susceptible to damage in comparison with pigmentary glaucoma.

Progressive Decrease of Peripapillary Angioflow Vessel Density During Structural and Visual Field Progression in Early Primary Open-angle Glaucoma.

PubMed

Holló, Gábor

2017-07-01

To present a case of early primary open-angle glaucoma in which retinal nerve fiber layer thickness (RNFLT), ganglion cell complex (GCC), and visual field progression were accompanied with significant progression of peripapillary angioflow vessel density (PAFD) measured with optical coherence tomographic angiography. A 68-year-old female patient who was under topical intraocular pressure (IOP) lowering medication for 20 years for ocular hypertension of the right and preperimetric primary open-angle glaucoma of the left eye (with reproducible inferotemporal and superotemporal neuroretinal rim and RNFL loss) was prospectively imaged with the AngioVue OCT for RNFLT, GCC thickness, and PAFD, and investigated with the Octopus Normal G2 visual field test on the same days at 6-month intervals for 18 months, while the IOP of the left eye escaped from control. IOP of the left eye fluctuated between 14 and 30 mm Hg in the study period. RNFLT, GCC thickness, and peripapillary PAFD all decreased significantly (linear regression analysis, P=0.030, 0.040, and 0.020, respectively), and a significant 2.1 dB/y progression was seen for a superior visual field cluster. The RNFLT, peripapillary PAFD, and visual field of the right eye remained normal and unchanged. In our case IOP elevation, glaucomatous visual field conversion, and structural progression were accompanied with significant progressive decrease of peripapillary PAFD. The simultaneous thinning of RNFLT and GCC and decrease of peripapillary PAFD suggest that PAFD may potentially be an additional indicator of early progression in primary open-angle glaucoma.

Macular Thickness Variability in Primary Open Angle Glaucoma Patients using Optical Coherence Tomography

PubMed Central

Agarwal, Prakashchand; Sathyan, P; Saini, VK

2014-01-01

ABSTRACT Aim: To compare the difference of retinal macular thickness and macular volume using optical coherence tomography (OCT) in primary open angle glaucoma (POAG) patients with the normal subjects. Materials and methods: This observational case control study included primary open angle glaucoma (POAG) patients (n = 124 eyes) and healthy subjects in the control group (n = 124 eyes). All subjects underwent detailed history, general and systemic exami -nation. Complete ocular examination included best corrected visual acuity (BCVA), slit lamp examination, intraocular pressure (IOP), central corneal thickness, gonioscopy, dilated fundus biomicroscopy. Field analysis was done by white on white Humphrey Field Analyzer (Carl Zeiss). Optical coherence tomography imaging of macular area was performed using Stratus OCT (OCT 3, Version 4, Carl Zeiss Inc, Dublin, California, USA). In both these groups, parameters analyzed were macular thickness, inner macular thicknesses (IMT), outer macular thicknesses (OMT), central macular thick ness (CMT) and total macular volume (TMV). Results: The POAG group had significantly decreased values of TMV, OMT and IMT, compared to control group, while there was no difference in CMT, presumably due to absence of ganglion cells in the central part. Thus, macular thickness and volume parameters may be used for making the diagnosis of glaucoma especially in patients with abnormalities of disc. Conclusion: Macular thickness parameters correlated well with the diagnosis of glaucoma. How to cite this article: Sharma A, Agarwal P, Sathyan P, Saini VK. Macular Thickness Variability in Primary Open Angle Glaucoma Patients using Optical Coherence Tomography. J Current Glau Prac 2014;8(1):10-14. PMID:26997801

Glymphatic stasis at the site of the lamina cribrosa as a potential mechanism underlying open-angle glaucoma.

PubMed

Wostyn, Peter; Killer, Hanspeter Esriel; De Deyn, Peter Paul

2017-07-01

The underlying pathophysiology of primary open-angle glaucoma remains unclear, but the lamina cribrosa seems to be the primary site of injury, and raised intraocular pressure is a major risk factor. In recent years, a decreased intracranial pressure, leading to an abnormally high trans-lamina cribrosa pressure difference, has gained interest as a new risk factor for glaucoma. New research now lends support to the hypothesis that a paravascular transport system is present in the eye analogous to the recently discovered 'glymphatic system' in the brain, which is a functional waste clearance pathway that promotes elimination of interstitial solutes, including β-amyloid, from the brain along paravascular channels. Given that β-amyloid has been reported to increase by chronic elevation of intraocular pressure in glaucomatous animal models and to cause retinal ganglion cell death, the discovery of a paravascular clearance system in the eye may provide powerful new insights into the pathophysiology of primary open-angle glaucoma. In this review, we provide a new conceptual framework for understanding the pathogenesis of primary open-angle glaucoma, present supporting preliminary data from our own post-mortem study and hypothesize that the disease may result from restriction of normal glymphatic flow at the level of the lamina cribrosa owing to a low intracranial pressure and/or a high trans-lamina cribrosa pressure gradient. If confirmed, this viewpoint could offer new perspectives for the development of novel diagnostic and therapeutic strategies for this devastating disorder. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

Distinguishable circumferential inclined direction tilt sensor based on fiber Bragg grating with wide measuring range and high accuracy

NASA Astrophysics Data System (ADS)

Jiang, Shanchao; Wang, Jing; Sui, Qingmei

2015-11-01

One novel distinguishable circumferential inclined direction tilt sensor is demonstrated by incorporating two strain sensitivity fiber Bragg gratings (FBGs) with two orthogonal triangular cantilever beam and using one fiber Bragg grating (FBG) as temperature compensation element. According to spatial vector and space geometry, theory calculation model of the proposed FBG tilt sensor which can be used to obtain the azimuth and tile angle of the inclined direction is established. To obtain its measuring characteristics, calibration experiment on one prototype of the proposed FBG tilt sensor is carried out. After temperature sensitivity experiment data analysis, the proposed FBG tilt sensor exhibits excellent temperature compensation characteristics. In 2-D tilt angle experiment, tilt measurement sensitivities of these two strain sensitivity FBGs are 140.85°/nm and 101.01°/nm over a wide range of 60º. Further, azimuth and tile angle of the inclined direction can be obtained by the proposed FBG tilt sensor which is verified in circumferential angle experiment. Experiment data show that relative errors of azimuth are 0.55% (positive direction) and 1.14% (negative direction), respectively, and relative errors of tilt angle are all less than 3%. Experiment results confirm that the proposed distinguishable circumferential inclined direction tilt sensor based on FBG can achieve azimuth and tile angle measurement with wide measuring range and high accuracy.

Gamma-Ray Burst Jet Breaks Revisited

NASA Astrophysics Data System (ADS)

Wang, Xiang-Gao; Zhang, Bing; Liang, En-Wei; Lu, Rui-Jing; Lin, Da-Bin; Li, Jing; Li, Long

2018-06-01

Gamma-ray Burst (GRB) collimation has been inferred with the observations of achromatic steepening in GRB light curves, known as jet breaks. Identifying a jet break from a GRB afterglow light curve allows a measurement of the jet opening angle and true energetics of GRBs. In this paper, we re-investigate this problem using a large sample of GRBs that have an optical jet break that is consistent with being achromatic in the X-ray band. Our sample includes 99 GRBs from 1997 February to 2015 March that have optical and, for Swift GRBs, X-ray light curves that are consistent with the jet break interpretation. Out of the 99 GRBs we have studied, 55 GRBs are found to have temporal and spectral behaviors both before and after the break, consistent with the theoretical predictions of the jet break models, respectively. These include 53 long/soft (Type II) and 2 short/hard (Type I) GRBs. Only 1 GRB is classified as the candidate of a jet break with energy injection. Another 41 and 3 GRBs are classified as the candidates with the lower and upper limits of the jet break time, respectively. Most jet breaks occur at 90 ks, with a typical opening angle θj = (2.5 ± 1.0)°. This gives a typical beaming correction factor {f}b-1∼ 1000 for Type II GRBs, suggesting an even higher total GRB event rate density in the universe. Both isotropic and jet-corrected energies have a wide span in their distributions: log(Eγ,iso/erg) = 53.11 with σ = 0.84 log(EK,iso/erg) = 54.82 with σ = 0.56 log(Eγ/erg) = 49.54 with σ = 1.29 and log(EK/erg) = 51.33 with σ = 0.58. We also investigate several empirical correlations (Amati, Frail, Ghirlanda, and Liang–Zhang) previously discussed in the literature. We find that in general most of these relations are less tight than before. The existence of early jet breaks and hence small opening angle jets, which were detected in the Swfit era, is most likely the source of scatter. If one limits the sample to jet breaks later than 104 s, the Liang–Zhang relation remains tight and the Ghirlanda relation still exists. These relations are derived from Type II GRBs, and Type I GRBs usually deviate from them.

New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics

PubMed Central

Springelkamp, Henriët; Iglesias, Adriana I.; Mishra, Aniket; Höhn, René; Wojciechowski, Robert; Khawaja, Anthony P.; Nag, Abhishek; Wang, Ya Xing; Wang, Jie Jin; Cuellar-Partida, Gabriel; Gibson, Jane; Bailey, Jessica N. Cooke; Vithana, Eranga N.; Gharahkhani, Puya; Boutin, Thibaud; Ramdas, Wishal D.; Zeller, Tanja; Luben, Robert N.; Yonova-Doing, Ekaterina; Viswanathan, Ananth C.; Yazar, Seyhan; Cree, Angela J.; Haines, Jonathan L.; Koh, Jia Yu; Souzeau, Emmanuelle; Wilson, James F.; Amin, Najaf; Müller, Christian; Venturini, Cristina; Kearns, Lisa S.; Kang, Jae Hee; Tham, Yih Chung; Zhou, Tiger; van Leeuwen, Elisabeth M.; Nickels, Stefan; Sanfilippo, Paul; Liao, Jiemin; van der Linde, Herma; Zhao, Wanting; van Koolwijk, Leonieke M.E.; Zheng, Li; Rivadeneira, Fernando; Baskaran, Mani; van der Lee, Sven J.; Perera, Shamira; de Jong, Paulus T.V.M.; Oostra, Ben A.; Uitterlinden, André G.; Fan, Qiao; Hofman, Albert; Tai, E-Shyong; Vingerling, Johannes R.; Sim, Xueling; Wolfs, Roger C.W.; Teo, Yik Ying; Lemij, Hans G.; Khor, Chiea Chuen; Willemsen, Rob; Lackner, Karl J.; Aung, Tin; Jansonius, Nomdo M.; Montgomery, Grant; Wild, Philipp S.; Young, Terri L.; Burdon, Kathryn P.; Hysi, Pirro G.; Pasquale, Louis R.; Wong, Tien Yin; Klaver, Caroline C.W.; Hewitt, Alex W.; Jonas, Jost B.; Mitchell, Paul; Lotery, Andrew J.; Foster, Paul J.; Vitart, Veronique; Pfeiffer, Norbert; Craig, Jamie E.; Mackey, David A.; Hammond, Christopher J.; Wiggs, Janey L.; Cheng, Ching-Yu; van Duijn, Cornelia M.; MacGregor, Stuart

2017-01-01

Abstract Primary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increased risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We conducted a genome-wide association meta-analysis of IOP and optic disc parameters and validated our findings in multiple sets of POAG cases and controls. Using imputation to the 1000 genomes (1000G) reference set, we identified 9 new genomic regions associated with vertical cup-disc ratio (VCDR) and 1 new region associated with IOP. Additionally, we found 5 novel loci for optic nerve cup area and 6 for disc area. Previously it was assumed that genetic variation influenced POAG either through IOP or via changes to the optic nerve head; here we present evidence that some genomic regions affect both IOP and the disc parameters. We characterized the effect of the novel loci through pathway analysis and found that pathways involved are not entirely distinct as assumed so far. Further, we identified a novel association between CDKN1A and POAG. Using a zebrafish model we show that six6b (associated with POAG and optic nerve head variation) alters the expression of cdkn1a. In summary, we have identified several novel genes influencing the major clinical risk predictors of POAG and showed that genetic variation in CDKN1A is important in POAG risk. PMID:28073927

Effects of Geometrical and Flow Rates on the Prediction of Bottom Pressure Coefficients of Tunnel Lift Gate of Dams

NASA Astrophysics Data System (ADS)

Ameen, Sheeraz; Taher, Taha; Ahmed, Thamir M.

2018-06-01

Hydrostatics and hydrodynamics forces are generated and applied on the vertical lift tunnel gates due to the influence of a wide range of dam operating conditions. One of the most important forces is the uplift force resulting from the jet flow issuing below the gate. This force is based mainly upon many hydraulic and geometrical parameters. In this work, the uplift force is studied in terms of bottom pressure coefficient. The investigation is made paying particular attention on the effects of various three discharges and three gate lip angles on values of bottom pressure coefficients in addition to four different tunnel longitudinal slopes whose impact has not been studied in many previous works. Hydraulic model is constructed in this work for the sake of measuring all parameters required for estimating the bottom pressure coefficients, which are all examined against gate openings. The results show that the bottom pressure coefficient is related to the said variables, however, its behaviour and values are not necessary regular with variance of studied variables. The values are seen more significantly related to the flow rates and for some extent to the slopes of tunnel. An attempt by using the nonlinear regression of Statistical package of social sciences (SPSS) is made to set equations relating bottom pressure coefficient with gate openings for several angles of gate lips. The obtained equations are shown in good agreement with the selected cases of experimental results. The results are applicable for design purposes for similar geometrical and flow parameters considered in this study.

Constitutive description of human femoropopliteal artery aging.

PubMed

Kamenskiy, Alexey; Seas, Andreas; Deegan, Paul; Poulson, William; Anttila, Eric; Sim, Sylvie; Desyatova, Anastasia; MacTaggart, Jason

2017-04-01

Femoropopliteal artery (FPA) mechanics play a paramount role in pathophysiology and the artery's response to therapeutic interventions, but data on FPA mechanical properties are scarce. Our goal was to characterize human FPAs over a wide population to derive a constitutive description of FPA aging to be used for computational modeling. Fresh human FPA specimens ([Formula: see text]) were obtained from [Formula: see text] predominantly male (80 %) donors 54±15 years old (range 13-82 years). Morphometric characteristics including radius, wall thickness, opening angle, and longitudinal pre-stretch were recorded. Arteries were subjected to multi-ratio planar biaxial extension to determine constitutive parameters for an invariant-based model accounting for the passive contributions of ground substance, elastin, collagen, and smooth muscle. Nonparametric bootstrapping was used to determine unique sets of material parameters that were used to derive age-group-specific characteristics. Physiologic stress-stretch state was calculated to capture changes with aging. Morphometric and constitutive parameters were derived for seven age groups. Vessel radius, wall thickness, and circumferential opening angle increased with aging, while longitudinal pre-stretch decreased ([Formula: see text]). Age-group-specific constitutive parameters portrayed orthotropic FPA stiffening, especially in the longitudinal direction. Structural changes in artery wall elastin were associated with reduction of physiologic longitudinal and circumferential stretches and stresses with age. These data and the constitutive description of FPA aging shed new light on our understanding of peripheral arterial disease pathophysiology and arterial aging. Application of this knowledge might improve patient selection for specific treatment modalities in personalized, precision medicine algorithms and could assist in device development for treatment of peripheral artery disease.

Production, Thermalization and Transport of Photoelectrons in the Mars Environment

NASA Astrophysics Data System (ADS)

Mitchell, D. L.; Xu, S.; Mazelle, C. X.; Steckiewicz, M.; Luhmann, J. G.; Connerney, J. E. P.; Andersson, L.

2016-12-01

The Solar Wind Electron Analyzer (SWEA) on the MAVEN spacecraft provides a detailed look at the production, thermalization, and transport of photoelectrons in the Mars environment. The MAVEN orbit routinely samples altitudes down to 150 km over wide ranges of solar zenith angle, local time, longitude, latitude and altitude. The altitude range extends into the region of photochemical equilibrium. SWEA's nominal energy resolution of 17% (ΔE/E, FWHM) is insufficient to resolve the photoelectron peaks at 23 and 27 eV, which result from photoionization of CO2 and O by the intense He II line in the solar EUV spectrum. However, during some orbits the spacecraft charged to -18 V near periapsis, which shifted the He II photoelectron features to lower energies, thus allowing them to be resolved. During several week-long deep dip campaigns, the periapsis altitude was lowered to 120 km. Thermalization of primary photoelectrons is very rapid at this altitude, resulting in a residual population at 7 eV, where the cross section to interaction with CO2 has a minimum. At altitudes above the 200 km, collisions become negligible (mean free path > 100 km), and the motion of suprathermal electrons is controlled by the magnetic field. Electron energy-pitch angle distributions reveal transport of photoelectrons from the day to the night hemisphere on both closed crustal magnetic loops and on open lines that extend into the tail. Mapping of such open field lines reveals the regions of the tail with access to the day-side ionosphere, which provide a conduit for ion outflow and loss.

Impact of the slab dip change onto the deformation partitioning in the northern Lesser Antilles oblique subduction zone (Antigua-Virgin Islands)

NASA Astrophysics Data System (ADS)

Laurencin, Muriel; Marcaillou, Boris; Klingelhoefer, Frauke; Graindorge, David; Lebrun, Jean-Frédéric; Laigle, Mireille; Lallemand, Serge

2017-04-01

Marine geophysical cruises Antithesis (2013-2016) investigate the impact of the variations in interplate geometry onto margin tectonic deformation along the strongly oblique Lesser Antilles subduction zone. A striking features of this margin is the drastic increase in earthquake number from the quiet Barbuda-St Martin segment to the Virgin Islands platform. Wide-angle seismic data highlight a northward shallowing of the downgoing plate: in a 150 km distance from the deformation front, the slab dipping angle in the convergence direction decreases from 12° offshore of Antigua Island to 7° offshore of Virgin Islands. North-South wide-angle seismic line substantiates a drastic slab-dip change that likely causes this northward shallowing. This dip change is located beneath the southern tip of the Virgin Islands platform where the Anegada Passage entails the upper plate. Based on deep seismic lines and bathymetric data, the Anegada Passage is a 450 km long W-E trending set of pull-apart basins and strike-slip faults that extends from the Lesser Antilles accretionary prism to Puerto Rico. The newly observed sedimentary architecture within pull-apart Sombrero and Malliwana basins indicates a polyphased tectonic history. A past prominent NW-SE extensive to transtensive phase, possibly related to the Bahamas Bank collision, opened the Anegada Passage as previously published. Transpressive tectonic evidences indicate that these structures have been recently reactivated in an en-echelon sinistral strike-slip system. The interpreted strain ellipsoid is consistent with deformation partitioning. We propose that the slab northward shallowing increases the interplate coupling and the seismic activity beneath the Virgin Islands platform comparatively to the quiet Barbuda-St Martin segment. It is noteworthy that the major tectonic partitioning structure in the Lesser Antilles forearc is located above the slab dip change where the interplate seismic coupling increases.

Enhancement in Open-Circuit Voltage in Organic Solar Cells by Using Ladder-Type Nonfullerene Acceptors

DOE PAGES

Cai, Zhengxu; Zhao, Donglin; Sharapov, Valerii; ...

2018-03-28

The open-circuit voltage (V oc) loss has always been a major factor in lowering power conversion efficiencies (PCEs) in bulk heterojunction organic photovoltaic cells (OPVs). A method to improve the V oc is indispensable to achieve high PCEs. Here in this paper, we investigated a series of perylene diimide-based ladder-type molecules as electron acceptors in nonfullerene OPVs. The D-A ladder-type structures described here lock our pi-systems into a planar structure and eliminate bond twisting associated with linear conjugated systems. This enlarges the interface energy gap (ΔE DA), extends electronic delocalization, and hence improves the V oc. More importantly, these devicesmore » showed an increase in V oc without compromising either the J sc or the FF. C5r exhibited a strong intermolecular interaction and a PCE value of 6.1%. Moreover, grazing-incident wide-angle X-ray scattering analysis and atomic force microscopy images suggested that our fused-ring acceptors showed a suitable domain size and uniform blend films, which were not affected by their rigid molecular structures.« less

Enhancement in Open-Circuit Voltage in Organic Solar Cells by Using Ladder-Type Nonfullerene Acceptors.

PubMed

Cai, Zhengxu; Zhao, Donglin; Sharapov, Valerii; Awais, Mohammad A; Zhang, Na; Chen, Wei; Yu, Luping

2018-04-25

The open-circuit voltage ( V oc ) loss has always been a major factor in lowering power conversion efficiencies (PCEs) in bulk heterojunction organic photovoltaic cells (OPVs). A method to improve the V oc is indispensable to achieve high PCEs. In this paper, we investigated a series of perylene diimide-based ladder-type molecules as electron acceptors in nonfullerene OPVs. The D-A ladder-type structures described here lock our π-systems into a planar structure and eliminate bond twisting associated with linear conjugated systems. This enlarges the interface energy gap (Δ E DA ), extends electronic delocalization, and hence improves the V oc . More importantly, these devices showed an increase in V oc without compromising either the J sc or the FF. C5r exhibited a strong intermolecular interaction and a PCE value of 6.1%. Moreover, grazing-incident wide-angle X-ray scattering analysis and atomic force microscopy images suggested that our fused-ring acceptors showed a suitable domain size and uniform blend films, which were not affected by their rigid molecular structures.

Enhancement in Open-Circuit Voltage in Organic Solar Cells by Using Ladder-Type Nonfullerene Acceptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Zhengxu; Zhao, Donglin; Sharapov, Valerii

The open-circuit voltage (V oc) loss has always been a major factor in lowering power conversion efficiencies (PCEs) in bulk heterojunction organic photovoltaic cells (OPVs). A method to improve the V oc is indispensable to achieve high PCEs. Here in this paper, we investigated a series of perylene diimide-based ladder-type molecules as electron acceptors in nonfullerene OPVs. The D-A ladder-type structures described here lock our pi-systems into a planar structure and eliminate bond twisting associated with linear conjugated systems. This enlarges the interface energy gap (ΔE DA), extends electronic delocalization, and hence improves the V oc. More importantly, these devicesmore » showed an increase in V oc without compromising either the J sc or the FF. C5r exhibited a strong intermolecular interaction and a PCE value of 6.1%. Moreover, grazing-incident wide-angle X-ray scattering analysis and atomic force microscopy images suggested that our fused-ring acceptors showed a suitable domain size and uniform blend films, which were not affected by their rigid molecular structures.« less

The directivity of the sound radiation from panels and openings.

PubMed

Davy, John L

2009-06-01

This paper presents a method for calculating the directivity of the radiation of sound from a panel or opening, whose vibration is forced by the incidence of sound from the other side. The directivity of the radiation depends on the angular distribution of the incident sound energy in the room or duct in whose wall or end the panel or opening occurs. The angular distribution of the incident sound energy is predicted using a model which depends on the sound absorption coefficient of the room or duct surfaces. If the sound source is situated in the room or duct, the sound absorption coefficient model is used in conjunction with a model for the directivity of the sound source. For angles of radiation approaching 90 degrees to the normal to the panel or opening, the effect of the diffraction by the panel or opening, or by the finite baffle in which the panel or opening is mounted, is included. A simple empirical model is developed to predict the diffraction of sound into the shadow zone when the angle of radiation is greater than 90 degrees to the normal to the panel or opening. The method is compared with published experimental results.

Periodic-disturbance accommodating control of the space station for asymptotic momentum management

NASA Technical Reports Server (NTRS)

Warren, Wayne; Wie, Bong; Geller, David

1989-01-01

Periodic-disturbance accommodating control is investigated for asymptotic momentum management of control moment gyros used as primary actuating devices for the Space Station. The proposed controller utilizes the concepts of quaternion feedback control and periodic-disturbance accommodation to achieve oscillations about the constant torque equilibrium attitude, while minimizing the control effort required. Three-axis coupled equations of motion, written in terms of quaternions, are derived for roll/yaw controller design and stability analysis. The quaternion feedback controller designed using the linear-quadratic regulator synthesis technique is shown to be robust for a wide range of pitch angles. It is also shown that the proposed controller tunes the open-loop unstable vehicle to a stable oscillatory motion which minimizes the control effort needed for steady-state operations.

Incident angle of saltating particles in wind-blown sand.

PubMed

Fu, Lin-Tao; Bo, Tian-Li; Gu, Hai-Hua; Zheng, Xiao-Jing

2013-01-01

Incident angle of saltating particles plays a very important role in aeolian events. In this paper, the incident angles of sand particles near the sand bed were measured in wind tunnel. It reveals that the incident angles range widely from 0° to 180° and thereby the means of angles are larger than published data. Surprisingly, it is found the proportion that angles of 5°-15° occupy is far below previous reports. The measuring height is probably the most important reason for the measurement differences between this study and previous investigations.

ARC-1990-AC79-7127

NASA Image and Video Library

1990-02-14

Range : 4 billion miles from Earth, at 32 degrees to the ecliptic. P-36057C This color image of the Sun, Earth, and Venus is one of the first, and maybe, only images that show are solar system from such a vantage point. The image is a portion of a wide angle image containing the sun and the region of space where the Earth and Venus were at the time, with narrow angle cameras centered on each planet. The wide angle was taken with the cameras darkest filter, a methane absorption band, and the shortest possible exposure, one two-hundredth of a second, to avoid saturating the camera's vidicon tube with scattered sunlight. The sun is not large in the sky, as seen from Voyager's perpective at the edge of the solar system. Yet, it is still 8xs brighter than the brightest star in Earth's sky, Sirius. The image of the sun you see is far larger than the actual dimension of the solar disk. The result of the brightness is a bright burned out image with multiple reflections from the optics of the camera. The rays around th sun are a diffraction pattern of the calibration lamp which is mounted in front of the wide angle lens. the 2 narrow angle frames containing the images of the Earth and Venus have been digitally mosaicked into the wide angle image at the appropriate scale. These images were taken through three color filters and recombined to produce the color image. The violet, green, and blue filters used , as well as exposure times of .72,.48, and .72 for Earth, and .36, .24, and .36 for Venus.The images also show long linear streaks resulting from scatering of sulight off parts of the camera and its shade.

An Experimental Investigation on the Generation of a Stable Arch in Granular Materials Using a Developed Trapdoor Apparatus

NASA Astrophysics Data System (ADS)

Ahmadi, Ali; Seyedi Hosseininia, Ehsan

2017-06-01

This paper discusses the formation of stable arches in granular materials by using a series of laboratory tests. To this aim, a developed trapdoor apparatus is designed to find dimensions of arches formed over the door in cohesionless aggregates. This setup has two new important applications. In order to investigate the maximum width of the opening generated exactly on the verge of failure, the door can be open to an arbitrary size. In addition, the box containing granular materials (or base angle) is able to be set on optional angles from zero to 90 degrees with respect to the horizontal. Therefore, it is possible to understand the effect of different levels of gravity accelerations on the formed arches. It is observed that for all tested granular materials, increasing the door size and decreasing the base angle, both cause to increase the width and height of the arch. Moreover, the shape of all arches is governed by a parabola. Furthermore, the maximum door width is approximately five to 8.6 times the particle size, depending on the internal friction angle of materials and the base angle.

Miranda

NASA Image and Video Library

1999-08-24

One wide-angle and eight narrow-angle camera images of Miranda, taken by NASA Voyager 2, were combined in this view. The controlled mosaic was transformed to an orthographic view centered on the south pole.

High diffraction efficiency of three-layer diffractive optics designed for wide temperature range and large incident angle.

PubMed

Mao, Shan; Cui, Qingfeng; Piao, Mingxu; Zhao, Lidong

2016-05-01

A mathematical model of diffraction efficiency and polychromatic integral diffraction efficiency affected by environment temperature change and incident angle for three-layer diffractive optics with different dispersion materials is put forward, and its effects are analyzed. Taking optical materials N-FK5 and N-SF1 as the substrates of multilayer diffractive optics, the effect on diffraction efficiency and polychromatic integral diffraction efficiency with intermediate materials POLYCARB is analyzed with environment temperature change as well as incident angle. Therefore, three-layer diffractive optics can be applied in more wide environmental temperature ranges and larger incident angles for refractive-diffractive hybrid optical systems, which can obtain better image quality. Analysis results can be used to guide the hybrid imaging optical system design for optical engineers.

Establishing Age-Adjusted Reference Ranges for Iris-Related Parameters in Open Angle Eyes with Anterior Segment Optical Coherence Tomography

PubMed Central

Peterson, Jeffrey R.; Blieden, Lauren S.; Chuang, Alice Z.; Baker, Laura A.; Rigi, Mohammed; Feldman, Robert M.; Bell, Nicholas P.

2016-01-01

Purpose Define criteria for iris-related parameters in an adult open angle population as measured with swept source Fourier domain anterior segment optical coherence tomography (ASOCT). Methods Ninety-eight eyes of 98 participants with open angles were included and stratified into 5 age groups (18–35, 36–45, 46–55, 56–65, and 66–79 years). ASOCT scans with 3D mode angle analysis were taken with the CASIA SS-1000 (Tomey Corporation, Nagoya, Japan) and analyzed using the Anterior Chamber Analysis and Interpretation software. Anterior iris surface length (AISL), length of scleral spur landmark (SSL) to pupillary margin (SSL-to-PM), iris contour ratio (ICR = AISL/SSL-to-PM), pupil radius, radius of iris centroid (RICe), and iris volume were measured. Outcome variables were summarized for all eyes and age groups, and mean values among age groups were compared using one-way analysis of variance. Stepwise regression analysis was used to investigate demographic and ocular characteristic factors that affected each iris-related parameter. Results Mean (±SD) values were 2.24 mm (±0.46), 4.06 mm (±0.27), 3.65 mm (±0.48), 4.16 mm (±0.47), 1.14 (±0.04), 1.51 mm2 (±0.23), and 38.42 μL (±4.91) for pupillary radius, RICe, SSL-to-PM, AISL, ICR, iris cross-sectional area, and iris volume, respectively. Both pupillary radius (P = 0.002) and RICe (P = 0.027) decreased with age, while SSL-to-PM (P = 0.002) and AISL increased with age (P = 0.001). ICR (P = 0.54) and iris volume (P = 0.49) were not affected by age. Conclusion This study establishes reference values for iris-related parameters in an adult open angle population, which will be useful for future studies examining the role of iris changes in pathologic states. PMID:26815917

Establishing Age-Adjusted Reference Ranges for Iris-Related Parameters in Open Angle Eyes with Anterior Segment Optical Coherence Tomography.

PubMed

Peterson, Jeffrey R; Blieden, Lauren S; Chuang, Alice Z; Baker, Laura A; Rigi, Mohammed; Feldman, Robert M; Bell, Nicholas P

2016-01-01

Define criteria for iris-related parameters in an adult open angle population as measured with swept source Fourier domain anterior segment optical coherence tomography (ASOCT). Ninety-eight eyes of 98 participants with open angles were included and stratified into 5 age groups (18-35, 36-45, 46-55, 56-65, and 66-79 years). ASOCT scans with 3D mode angle analysis were taken with the CASIA SS-1000 (Tomey Corporation, Nagoya, Japan) and analyzed using the Anterior Chamber Analysis and Interpretation software. Anterior iris surface length (AISL), length of scleral spur landmark (SSL) to pupillary margin (SSL-to-PM), iris contour ratio (ICR = AISL/SSL-to-PM), pupil radius, radius of iris centroid (RICe), and iris volume were measured. Outcome variables were summarized for all eyes and age groups, and mean values among age groups were compared using one-way analysis of variance. Stepwise regression analysis was used to investigate demographic and ocular characteristic factors that affected each iris-related parameter. Mean (±SD) values were 2.24 mm (±0.46), 4.06 mm (±0.27), 3.65 mm (±0.48), 4.16 mm (±0.47), 1.14 (±0.04), 1.51 mm2 (±0.23), and 38.42 μL (±4.91) for pupillary radius, RICe, SSL-to-PM, AISL, ICR, iris cross-sectional area, and iris volume, respectively. Both pupillary radius (P = 0.002) and RICe (P = 0.027) decreased with age, while SSL-to-PM (P = 0.002) and AISL increased with age (P = 0.001). ICR (P = 0.54) and iris volume (P = 0.49) were not affected by age. This study establishes reference values for iris-related parameters in an adult open angle population, which will be useful for future studies examining the role of iris changes in pathologic states.

Wide field strip-imaging optical system

NASA Technical Reports Server (NTRS)

Vaughan, Arthur H. (Inventor)

1994-01-01

A strip imaging wide angle optical system is provided. The optical system is provided with a 'virtual' material stop to avoid aberrational effects inherent in wide angle optical systems. The optical system includes a spherical mirror section for receiving light from a 180-degree strip or arc of a target image. Light received by the spherical mirror section is reflected to a frusto-conical mirror section for subsequent rereflection to a row of optical fibers. Each optical fiber transmits a portion of the received light to a detector. The optical system exploits the narrow cone of acceptance associated with optical fibers to substantially eliminate vignetting effects inherent in wide-angle systems. Further, the optical system exploits the narrow cone of acceptance of the optical fibers to substantially limit spherical aberration. The optical system is ideally suited for any application wherein a 180-degree strip image need be detected, and is particularly well adapted for use in hostile environments such as in planetary exploration.

Solutions on a high-speed wide-angle zoom lens with aspheric surfaces

NASA Astrophysics Data System (ADS)

Yamanashi, Takanori

2012-10-01

Recent development in CMOS and digital camera technology has accelerated the business and market share of digital cinematography. In terms of optical design, this technology has increased the need to carefully consider pixel pitch and characteristics of the imager. When the field angle at the wide end, zoom ratio, and F-number are specified, choosing an appropriate zoom lens type is crucial. In addition, appropriate power distributions and lens configurations are required. At points near the wide end of a zoom lens, it is known that an aspheric surface is an effective means to correct off-axis aberrations. On the other hand, optical designers have to focus on manufacturability of aspheric surfaces and perform required analysis with respect to the surface shape. Centration errors aside, it is also important to know the sensitivity to aspheric shape errors and their effect on image quality. In this paper, wide angle cine zoom lens design examples are introduced and their main characteristics are described. Moreover, technical challenges are pointed out and solutions are proposed.

Ultra-broadband and wide-angle perfect absorber based on composite metal-semiconductor grating

NASA Astrophysics Data System (ADS)

Li, Xu; Wang, Zongpeng; Hou, Yumin

2018-01-01

In this letter, we present an ultra-broadband and wide-angle perfect absorber based on composite Ge-Ni grating. Near perfect absorption above 90% is achieved in a wide frequency range from 150 nm to 4200 nm, which covers almost the full spectrum of solar radiation. The absorption keeps robust in a wide range of incident angle from 0º to 60º. The upper triangle Ge grating works as an antireflection coating. The lower Ni grating works as a reflector and an effective energy trapper. The guided modes inside Ge grating are excited due to reflection of the lower Ni grating surface. In longer wavelength band, gap surface plasmons (GSPs) in the Ni grating are excited and couple with the guided modes inside the Ge grating. The coupled modes extend the perfect absorption band to the near-infrared region (150 nm-4200 nm). This design has potential application in photovoltaic devices and thermal emitters.

Versatile transfer of aligned carbon nanotubes with polydimethylsiloxane as the intermediate

NASA Astrophysics Data System (ADS)

Zhu, Yanwu; Lim, Xiaodai; Chea Sim, Mong; Teck Lim, Chwee; Haur Sow, Chorng

2008-08-01

A simple technique to transfer aligned multi-walled carbon nanotubes (MWCNTs) is demonstrated in this work. With polydimethylsiloxane (PDMS) as the transfer medium, as-grown or patterned MWCNT arrays are directly transferred onto a wide variety of Pt-coated substrates such as glossy paper, cloth, polymers, glass slides, and metal foils at low temperatures. The surface of the transferred CNTs is cleaner with better alignment, compared with the as-grown one. Furthermore, the transferred CNTs show strong adhesion and good electric contact with the target substrates. A maximal current density of ~104 A cm-2 has been achieved from the CNT interconnects prepared with this technique. Because of the lower density and open-ended structures, improved field emission performance has been obtained from CNTs transferred on polymers, based on which flexible emitter devices can be fabricated. In addition, the surface of transferred CNTs becomes more hydrophilic, with an averaged contact angle of 93.4 ± 5.8°, in contrast to the super-hydrophobic as-grown CNT surface (contact angle 151.6 ± 5.5°). With versatile properties and flexible applications, the technique provides a simple and cost-effective way towards future nanodevices based on CNTs.

Shape Recovery with Concomitant Mechanical Strengthening of Amphiphilic Shape Memory Polymers in Warm Water

DOE PAGES

Zhang, Ben; DeBartolo, Janae E.; Song, Jie

2017-01-26

Maintaining adequate or enhancing mechanical properties of shape memory polymers (SMPs) after shape recovery in an aqueous environment are greatly desired for biomedical applications of SMPs as self-fitting tissue scaffolds or minimally invasive surgical implants. Here we report stable temporary shape fixing and facile shape recovery of biodegradable triblock amphiphilic SMPs containing a poly(ethylene glycol) (PEG) center block and flanking poly(lactic acid) or poly(lactic-co-glycolic acid) blocks in warm water, accompanied with concomitant enhanced mechanical strengths. Differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WXRD) and small-angle X-ray scattering (SAXS) analyses revealed that the unique stiffening of the amphiphilic SMPs upon hydrationmore » was due to hydration-driven microphase separation and PEG crystallization. We further demonstrated that the chemical composition of degradable blocks in these SMPs could be tailored to affect the persistence of hydration-induced stiffening upon subsequent dehydration. These properties combined open new horizons for these amphiphilic SMPs for smart weight-bearing in vivo applications (e.g. as self-fitting intervertebral discs). In conclusion, this study also provides a new material design strategy to strengthen polymers in aqueous environment in general.« less

Diving wedges

NASA Astrophysics Data System (ADS)

Vincent, Lionel; Kanso, Eva

2017-11-01

Diving induces large pressures during water entry, accompanied by the creation of cavity behind the diver and water splash ejected from the free water surface. To minimize impact forces, divers streamline their shape at impact. Here, we investigate the impact forces and splash evolution of diving wedges as a function of the wedge opening angle. A gradual transition from impactful to smooth entry is observed as the wedge angle decreases. After submersion, diving wedges experience significantly smaller drag forces (two-fold smaller) than immersed wedges. We characterize the shapes of the cavity and splash created by the wedge and find that they are independent of the entry velocity at short times, but that the splash exhibits distinct variations in shape at later times. Combining experimental approach and a discrete fluid particle model, we show that the splash shape is governed by a destabilizing Venturi-suction force due to air rushing between the splash and the water surface and a stabilizing force due to surface tension. These findings may have implications in a wide range of water entry problems, with applications in engineering and bio-related problems, including naval engineering, disease spreading and platform diving. This work was funded by the National Science Foundation.

A new fast scanning system for the measurement of large angle tracks in nuclear emulsions

NASA Astrophysics Data System (ADS)

Alexandrov, A.; Buonaura, A.; Consiglio, L.; D'Ambrosio, N.; De Lellis, G.; Di Crescenzo, A.; Di Marco, N.; Galati, G.; Lauria, A.; Montesi, M. C.; Pupilli, F.; Shchedrina, T.; Tioukov, V.; Vladymyrov, M.

2015-11-01

Nuclear emulsions have been widely used in particle physics to identify new particles through the observation of their decays thanks to their unique spatial resolution. Nevertheless, before the advent of automatic scanning systems, the emulsion analysis was very demanding in terms of well trained manpower. Due to this reason, they were gradually replaced by electronic detectors, until the '90s, when automatic microscopes started to be developed in Japan and in Europe. Automatic scanning was essential to conceive large scale emulsion-based neutrino experiments like CHORUS, DONUT and OPERA. Standard scanning systems have been initially designed to recognize tracks within a limited angular acceptance (θ lesssim 30°) where θ is the track angle with respect to a line perpendicular to the emulsion plane. In this paper we describe the implementation of a novel fast automatic scanning system aimed at extending the track recognition to the full angular range and improving the present scanning speed. Indeed, nuclear emulsions do not have any intrinsic limit to detect particle direction. Such improvement opens new perspectives to use nuclear emulsions in several fields in addition to large scale neutrino experiments, like muon radiography, medical applications and dark matter directional detection.

Determination of the structural phase and octahedral rotation angle in halide perovskites

NASA Astrophysics Data System (ADS)

dos Reis, Roberto; Yang, Hao; Ophus, Colin; Ercius, Peter; Bizarri, Gregory; Perrodin, Didier; Shalapska, Tetiana; Bourret, Edith; Ciston, Jim; Dahmen, Ulrich

2018-02-01

A key to the unique combination of electronic and optical properties in halide perovskite materials lies in their rich structural complexity. However, their radiation sensitive nature limits nanoscale structural characterization requiring dose efficient microscopic techniques in order to determine their structures precisely. In this work, we determine the space-group and directly image the Br halide sites of CsPbBr3, a promising material for optoelectronic applications. Based on the symmetry of high-order Laue zone reflections of convergent-beam electron diffraction, we identify the tetragonal (I4/mcm) structural phase of CsPbBr3 at cryogenic temperature. Electron ptychography provides a highly sensitive phase contrast measurement of the halide positions under low electron-dose conditions, enabling imaging of the elongated Br sites originating from the out-of-phase octahedral rotation viewed along the [001] direction of I4/mcm persisting at room temperature. The measurement of these features and comparison with simulations yield an octahedral rotation angle of 6.5°(±1.5°). The approach demonstrated here opens up opportunities for understanding the atomic scale structural phenomena applying advanced characterization tools on a wide range of radiation sensitive halide-based all-inorganic and hybrid organic-inorganic perovskites.

Breakthrough in 4π ion emission mechanism understanding in plasma focus devices

PubMed Central

Sohrabi, Mehdi; Zarinshad, Arefe; Habibi, Morteza

2016-01-01

Ion emission angular distribution mechanisms in plasma focus devices (PFD) have not yet been well developed and understood being due to the lack of an efficient wide-angle ion distribution image detection system to characterize a PFD space in detail. Present belief is that the acceleration of ions points from “anode top” upwards in forward direction within a small solid angle. A breakthrough is reported in this study, by mega-size position-sensitive polycarbonate ion image detection systems invented, on discovery of 4π ion emission from the “anode top” in a PFD space after plasma pinch instability and radial run-away of ions from the “anode cathodes array” during axial acceleration of plasma sheaths before the radial phase. These two ion emission source mechanisms behave respectively as a “Point Ion Source” and a “Line Ion Source” forming “Ion Cathode Shadows” on mega-size detectors. We believe that the inventions and discoveries made here will open new horizons for advanced ion emission studies towards better mechanisms understanding and in particular will promote efficient applications of PFDs in medicine, science and technology. PMID:27941832

Random Combinatorial Gradient Metasurface for Broadband, Wide-Angle and Polarization-Independent Diffusion Scattering.

PubMed

Zhuang, Yaqiang; Wang, Guangming; Liang, Jiangang; Cai, Tong; Tang, Xiao-Lan; Guo, Tongfeng; Zhang, Qingfeng

2017-11-29

This paper proposes an easy, efficient strategy for designing broadband, wide-angle and polarization-independent diffusion metasurface for radar cross section (RCS) reduction. A dual-resonance unit cell, composed of a cross wire and cross loop (CWCL), is employed to enhance the phase bandwidth covering the 2π range. Both oblique-gradient and horizontal-gradient phase supercells are designed for illustration. The numerical results agree well with the theoretical ones. To significantly reduce backward scattering, the random combinatorial gradient metasurface (RCGM) is subsequently constructed by collecting eight supercells with randomly distributed gradient directions. The proposed metasurface features an enhanced specular RCS reduction performance and less design complexity compared to other candidates. Both simulated and measured results show that the proposed RCGM can significantly suppress RCS and exhibits broadband, wide-angle and polarization independence features.

Dual-band wide-angle metamaterial perfect absorber based on the combination of localized surface plasmon resonance and Helmholtz resonance.

PubMed

Zhang, Changlei; Huang, Cheng; Pu, Mingbo; Song, Jiakun; Zhao, Zeyu; Wu, Xiaoyu; Luo, Xiangang

2017-07-18

In this article, a dual-band wide-angle metamaterial perfect absorber is proposed to achieve absorption at the wavelength where laser radar operates. It is composed of gold ring array and a Helmholtz resonance cavity spaced by a Si dielectric layer. Numerical simulation results reveal that the designed absorber displays two absorption peaks at the target wavelength of 10.6 μm and 1.064 μm with the large frequency ratio and near-unity absorptivity under the normal incidence. The wide-angle absorbing property and the polarization-insensitive feature are also demonstrated. Localized surface plasmons resonance and Helmholtz resonance are introduced to analyze and interpret the absorbing mechanism. The designed perfect absorber can be developed for potential applications in infrared stealth field.

Graft Angle its Relationship to Tomato Plant Survival

USDA-ARS?s Scientific Manuscript database

Growing plants that can withstand the rigors of open field production is imperative. This study examines the relationship of tensile strength to graft angle and plant survival. Tomato seedlings of ‘FL47’ and ‘Rutgers’ were used as scions on ‘Roma’ rootstock under greenhouse and healing chamber con...

Hydraulic droplet coarsening in open-channel capillaries

NASA Astrophysics Data System (ADS)

Warren, Patrick B.

2016-11-01

Over a range of liquid-solid contact angles, an open-channel capillary with curved or angled sides can show a maximum in the Laplace pressure as a function of the filling state. Examples include double-angle wedges, grooves scored into flat surfaces, steps on surfaces, and the groove between touching parallel cylinders. The liquid in such a channel exhibits a beading instability if the channel is filled beyond the Laplace pressure maximum. The subsequent droplet coarsening takes place by hydraulic transport through the connecting liquid columns that remain in the groove. A mean-field scaling argument predicts the characteristic droplet radius R ˜t1 /7 , as a function of time t . This is confirmed by one-dimensional simulations of the coarsening kinetics. Some remarks are also made on the spreading kinetics of an isolated drop deposited in such a channel.

The Research of the Parallel Computing Development from the Angle of Cloud Computing

NASA Astrophysics Data System (ADS)

Peng, Zhensheng; Gong, Qingge; Duan, Yanyu; Wang, Yun

2017-10-01

Cloud computing is the development of parallel computing, distributed computing and grid computing. The development of cloud computing makes parallel computing come into people’s lives. Firstly, this paper expounds the concept of cloud computing and introduces two several traditional parallel programming model. Secondly, it analyzes and studies the principles, advantages and disadvantages of OpenMP, MPI and Map Reduce respectively. Finally, it takes MPI, OpenMP models compared to Map Reduce from the angle of cloud computing. The results of this paper are intended to provide a reference for the development of parallel computing.

Measurement of surface tension and viscosity by open capillary techniques

DOEpatents

Rye,Robert R. , Yost,Frederick G.

1998-01-01

An open-channel capillary is provided, having preferably a v-shaped groove in a flat wettable surface. The groove has timing marks and a source marker in which the specimen to be tested is deposited. The time of passage between the timing marks is recorded, and the ratio of surface tension .gamma. to viscosity .mu. is determined from the equation given below: ##EQU1## where h.sub.0 is the groove depth, .alpha. is the groove angle, .theta. is the liquid/solid contact angle, and t is the flow time. It has been shown by the

The effects of tibia profile, distraction angle, and knee load on wedge instability and hinge fracture: A finite element study.

PubMed

Weng, Pei-Wei; Chen, Chia-Hsien; Luo, Chu-An; Sun, Jui-Sheng; Tsuang, Yang-Hwei; Cheng, Cheng-Kung; Lin, Shang-Chih

2017-04-01

Several plate systems for high tibial osteotomy (HTO) have been developed to stabilize the opening wedge of an osteotomized tibia. Among them, the TomoFix system, having a quasi-straight and T-shaped design, has been widely adopted in the literature. However, this system is implemented by inserting a lag (i.e., cortical) screw through the proximal combi-hole, to deform the plate and pull the distal tibia toward the plate. This process potentially induces plate springback and creates an elastic preload on the osteotomized tibia, especially at the lateral hinge of the distracted wedge. Using the finite-element method, this study aims to investigate the contoured effect of lag-screw application on the biomechanical behavior of the tibia-plate construct. Two tibial profiles (normal and more concave), three distraction angles (6°, 9°, and 12°), and three knee loads (intraoperative: contouring plate; postoperative: weight and nonweight bearing) are systematically varied in this study. The wedge instability and fracture risk at the lateral hinge are chosen as the comparison indices. The results show the necessity of preoperative planning for a precontoured procedure, rather than elastic deformation using a lag screw. Within the intraoperative period, a more concave tibial profile and/or reduced distraction angle (i.e., 6° or 9°) necessitate a higher compressive load to elastically deform the plate, thereby deteriorating the lateral-hinge fracture risk. A precontoured plate is recommended in the case that the proximal tibia is highly concave and the distraction angle is insufficient to stretch the tibial profile. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

The Use of Sun Elevation Angle for Stereogrammetric Boreal Forest Height in Open Canopies

NASA Technical Reports Server (NTRS)

Montesano, Paul M.; Neigh, Christopher; Sun, Guoqing; Duncanson, Laura Innice; Van Den Hoek, Jamon; Ranson, Kenneth Jon

2017-01-01

Stereogrammetry applied to globally available high resolution spaceborne imagery (HRSI; less than 5 m spatial resolution) yields fine-scaled digital surface models (DSMs) of elevation. These DSMs may represent elevations that range from the ground to the vegetation canopy surface, are produced from stereoscopic image pairs (stereo pairs) that have a variety of acquisition characteristics, and have been coupled with lidar data of forest structure and ground surface elevation to examine forest height. This work explores surface elevations from HRSI DSMs derived from two types of acquisitions in open canopy forests. We (1) apply an automated mass-production stereogrammetry workflow to along-track HRSI stereo pairs, (2) identify multiple spatially coincident DSMs whose stereo pairs were acquired under different solar geometry, (3) vertically co-register these DSMs using coincident spaceborne lidar footprints (from ICESat-GLAS) as reference, and(4) examine differences in surface elevations between the reference lidar and the co-registered HRSI DSMs associated with two general types of acquisitions (DSM types) from different sun elevation angles. We find that these DSM types, distinguished by sun elevation angle at the time of stereo pair acquisition, are associated with different surface elevations estimated from automated stereogrammetry in open canopy forests. For DSM values with corresponding reference ground surface elevation from spaceborne lidar footprints in open canopy northern Siberian Larix forests with slopes less than10, our results show that HRSI DSM acquired with sun elevation angles greater than 35deg and less than 25deg (during snow-free conditions) produced characteristic and consistently distinct distributions of elevation differences from reference lidar. The former include DSMs of near-ground surfaces with root mean square errors less than 0.68 m relative to lidar. The latter, particularly those with angles less than 10deg, show distributions with larger differences from lidar that are associated with open canopy forests whose vegetation surface elevations are captured. Terrain aspect did not have a strong effect on the distribution of vegetation surfaces. Using the two DSM types together, the distribution of DSM-differenced heights in forests (6.0 m, sigma = 1.4 m) was consistent with the distribution of plot-level mean tree heights (6.5m, sigma = 1.2 m). We conclude that the variation in sun elevation angle at time of stereo pair acquisition can create illumination conditions conducive for capturing elevations of surfaces either near the ground or associated with vegetation canopy. Knowledge of HRSI acquisition solar geometry and snow cover can be used to understand and combine stereogrammetric surface elevation estimates to co-register rand difference overlapping DSMs, providing a means to map forest height at fine scales, resolving the vertical structure of groups of trees from spaceborne platforms in open canopy forests.

Influence of Contact Angle, Growth Angle and Melt Surface Tension on Detached Solidification of InSb

NASA Technical Reports Server (NTRS)

Wang, Yazhen; Regel, Liya L.; Wilcox, William R.

2000-01-01

We extended the previous analysis of detached solidification of InSb based on the moving meniscus model. We found that for steady detached solidification to occur in a sealed ampoule in zero gravity, it is necessary for the growth angle to exceed a critical value, the contact angle for the melt on the ampoule wall to exceed a critical value, and the melt-gas surface tension to be below a critical value. These critical values would depend on the material properties and the growth parameters. For the conditions examined here, the sum of the growth angle and the contact angle must exceed approximately 130, which is significantly less than required if both ends of the ampoule are open.

A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion

NASA Astrophysics Data System (ADS)

Yagi, N.; Ohta, N.; Matsuo, T.; Tanaka, T.; Terada, Y.; Kamasaka, H.; Kometani, T.

2010-10-01

The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6μm at BL40XU and 50μm at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.

Crustal thickness variations across the Blue Ridge mountains, southern Appalachians: an alternative procedure for migrating wide-angle reflection data

Treesearch

Robert B. Hawman

2008-01-01

Migration of wide-angle reflections generated by quarry blasts suggests that crustal thickness increases from 38 km beneath the Carolina Terrane to 47–51 km along the southeastern flank of the Blue Ridge. The migration algorithm, developed for generating single-fold images from explosions and earthquakes recorded with isolated, short-aperture arrays, uses the localized...

The nature of crustal boundaries: combined interpretation of wide-angle and normal-incidence seismic data

NASA Astrophysics Data System (ADS)

Long, Roger E.; Matthews, Patricia A.; Graham, Daniel P.

1994-04-01

After a few seconds two-way traveltime, normal-incidence seismic reflection sections are composed mainly of assemblages of short reflections. Very rarely are seen continuous reflections that might correspond to the Moho or a mid-crustal discontinuity. The inferred continuity of these boundaries has traditionally come from refraction seismology. There is now a body of high quality, coincident wide-angle and normal-incidence seismic data that have been recorded with 50-100 m shot spacing and with high frequency sources (e.g. MOBIL, BABEL). The complexity and characteristics of the wide-angle arrivals seen on these data suggest that they do not originate from continuous boundaries. It is suggested that these arrivals are reflections from the same assemblage of short length reflectors that are responsible for normal-incidence reflections. Seismic velocities below the middle crust may (1) change corresponding to normal-incidence reflectivity, or (2) generally increase with depth with localised sills or lens structures of different velocity accounting for the observed reflections. Wide-angle arrivals that have traditionally been identified as reflections from crustal boundaries (e.g. the mid-crust and Moho) and which were considered indicative of a sharp velocity discontinuity from continuous boundaries, may instead result from a concentration of lamellae.

Imaging of retinal and choroidal vascular tumours

PubMed Central

Heimann, H; Jmor, F; Damato, B

2013-01-01

The most common intraocular vascular tumours are choroidal haemangiomas, vasoproliferative tumours, and retinal haemangioblastomas. Rarer conditions include cavernous retinal angioma and arteriovenous malformations. Options for ablating the tumour include photodynamic therapy, argon laser photocoagulation, trans-scleral diathermy, cryotherapy, anti-angiogenic agents, plaque radiotherapy, and proton beam radiotherapy. Secondary effects are common and include retinal exudates, macular oedema, epiretinal membranes, retinal fibrosis, as well as serous and tractional retinal detachment, which are treated using standard methods (ie, intravitreal anti-angiogenic agents or steroids as well as vitreoretinal procedures, such as epiretinal membrane peeling and release of retinal traction). The detection, diagnosis, and monitoring of vascular tumours and their complications have improved considerably thanks to advances in imaging. These include spectral domain and enhanced depth imaging optical coherence tomography (SD-OCT and EDI-OCT, respectively), wide-angle photography and angiography as well as wide-angle fundus autofluorescence. Such novel imaging has provided new diagnostic clues and has profoundly influenced therapeutic strategies so that vascular tumours and secondary effects are now treated concurrently instead of sequentially, enhancing any opportunities for conserving vision and the eye. In this review, we describe how SD-OCT, EDI-OCT, autofluorescence, wide-angle photography and wide-angle angiography have facilitated the evaluation of eyes with the more common vascular tumours, that is, choroidal haemangioma, retinal vasoproliferative tumours, and retinal haemangioblastoma. PMID:23196648

The Wide Angle Camera of the ROSETTA Mission

NASA Astrophysics Data System (ADS)

Barbieri, C.; Fornasier, S.; Verani, S.; Bertini, I.; Lazzarin, M.; Rampazzi, F.; Cremonese, G.; Ragazzoni, R.; Marzari, F.; Angrilli, F.; Bianchini, G. A.; Debei, S.; Dececco, M.; Guizzo, G.; Parzianello, G.; Ramous, P.; Saggin, B.; Zaccariotto, M.; Da Deppo, V.; Naletto, G.; Nicolosi, G.; Pelizzo, M. G.; Tondello, G.; Brunello, P.; Peron, F.

This paper aims to give a brief description of the Wide Angle Camera (WAC), built by the Centro Servizi e AttivitàSpaziali (CISAS) of the University of Padova for the ESA ROSETTA Mission to comet 46P/Wirtanen and asteroids 4979 Otawara and 140 Siwa. The WAC is part of the OSIRIS imaging system, which comprises also a Narrow Angle Camera (NAC) built by the Laboratoire d'Astrophysique Spatiale (LAS) of Marseille. CISAS had also the responsibility to build the shutter and the front cover mechanism for the NAC. The flight model of the WAC was delivered in December 2001, and has been already integrated on ROSETTA.

Optimization of nonimaging focusing heliostat in dynamic correction of astigmatism for a wide range of incident angles.

PubMed

Chong, Kok-Keong

2010-05-15

To overcome astigmatism has always been a great challenge in designing a heliostat capable of focusing the sunlight on a small receiver throughout the year. In this Letter, a nonimaging focusing heliostat with a dynamic adjustment of facet mirrors in a group manner has been analyzed for optimizing the astigmatic correction in a wide range of incident angles. This what is to the author's knowledge a new heliostat is not only designed to serve the purpose of concentrating sunlight to several hundreds of suns, but also to significantly reduce the variation of the solar flux distribution with the incident angle.

Theory, design, and experimental verification of a reflectionless bianisotropic Huygens' metasurface for wide-angle refraction

NASA Astrophysics Data System (ADS)

Chen, Michael; Abdo-Sánchez, Elena; Epstein, Ariel; Eleftheriades, George V.

2018-03-01

Huygens' metasurfaces are electrically thin devices which allow arbitrary field transformations. Beam refraction is among the first demonstrations of realized metasurfaces. As previously shown for extreme-angle refraction, control over only the electric impedance and magnetic admittance of the Huygens' metasurface proved insufficient to produce the desired reflectionless field transformation. To maintain zero reflections for wide refraction angles, magnetoelectric coupling between the electric and magnetic response of the metasurface, leading to bianisotropy, can be introduced. In this paper, we report the theory, design, and experimental characterization of a reflectionless bianisotropic metasurface for extreme-angle refraction of a normally incident plane wave towards 71.8° at 20 GHz. The theory and design of three-layer asymmetric bianisotropic unit cells are discussed. The realized printed circuit board structure was tested via full-wave simulations as well as experimental characterization. To experimentally verify the prototype, two setups were used. A quasi-optical experiment was conducted to assess the specular reflections of the metasurface, while a far-field antenna measurement characterized its refraction nature. The measurements verify that the fabricated metasurface has negligible reflections and the majority of the scattered power is refracted to the desired Floquet mode. This provides an experimental demonstration of a reflectionless wide-angle refracting metasurface using a bianisotropic Huygens' metasurface at microwave frequencies.

3D superwide-angle one-way propagator and its application in seismic modeling and imaging

NASA Astrophysics Data System (ADS)

Jia, Xiaofeng; Jiang, Yunong; Wu, Ru-Shan

2018-07-01

Traditional one-way wave-equation based propagators have been widely used in past decades. Comparing to two-way propagators, one-way methods have higher efficiency and lower memory demands. These two features are especially important in solving large-scale 3D problems. However, regular one-way propagators cannot simulate waves that propagate in large angles within 90° because of their inherent wide angle limitation. Traditional one-way can only propagate along the determined direction (e.g., z-direction), so simulation of turning waves is beyond the ability of one-way methods. We develop 3D superwide-angle one-way propagator to overcome angle limitation and to simulate turning waves with superwide-angle propagation angle (>90°) for modeling and imaging complex geological structures. Wavefields propagating along vertical and horizontal directions are combined using typical stacking scheme. A weight function related to the propagation angle is used for combining and updating wavefields in each propagating step. In the implementation, we use graphics processing units (GPU) to accelerate the process. Typical workflow is designed to exploit the advantages of GPU architecture. Numerical examples show that the method achieves higher accuracy in modeling and imaging steep structures than regular one-way propagators. Actually, superwide-angle one-way propagator can be applied based on any one-way method to improve the effects of seismic modeling and imaging.

Large displacement spherical joint

DOEpatents

Bieg, Lothar F.; Benavides, Gilbert L.

2002-01-01

A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

Ten-Meter Scale Topography and Roughness of Mars Exploration Rovers Landing Sites and Martian Polar Regions

NASA Technical Reports Server (NTRS)

Ivanov, Anton B.

2003-01-01

The Mars Orbiter Camera (MOC) has been operating on board of the Mars Global Surveyor (MGS) spacecraft since 1998. It consists of three cameras - Red and Blue Wide Angle cameras (FOV=140 deg.) and Narrow Angle camera (FOV=0.44 deg.). The Wide Angle camera allows surface resolution down to 230 m/pixel and the Narrow Angle camera - down to 1.5 m/pixel. This work is a continuation of the project, which we have reported previously. Since then we have refined and improved our stereo correlation algorithm and have processed many more stereo pairs. We will discuss results of our stereo pair analysis located in the Mars Exploration rovers (MER) landing sites and address feasibility of recovering topography from stereo pairs (especially in the polar regions), taken during MGS 'Relay-16' mode.

Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases.

PubMed

Iglesias, Adriana I; Mishra, Aniket; Vitart, Veronique; Bykhovskaya, Yelena; Höhn, René; Springelkamp, Henriët; Cuellar-Partida, Gabriel; Gharahkhani, Puya; Bailey, Jessica N Cooke; Willoughby, Colin E; Li, Xiaohui; Yazar, Seyhan; Nag, Abhishek; Khawaja, Anthony P; Polašek, Ozren; Siscovick, David; Mitchell, Paul; Tham, Yih Chung; Haines, Jonathan L; Kearns, Lisa S; Hayward, Caroline; Shi, Yuan; van Leeuwen, Elisabeth M; Taylor, Kent D; Bonnemaijer, Pieter; Rotter, Jerome I; Martin, Nicholas G; Zeller, Tanja; Mills, Richard A; Staffieri, Sandra E; Jonas, Jost B; Schmidtmann, Irene; Boutin, Thibaud; Kang, Jae H; Lucas, Sionne E M; Wong, Tien Yin; Beutel, Manfred E; Wilson, James F; Uitterlinden, André G; Vithana, Eranga N; Foster, Paul J; Hysi, Pirro G; Hewitt, Alex W; Khor, Chiea Chuen; Pasquale, Louis R; Montgomery, Grant W; Klaver, Caroline C W; Aung, Tin; Pfeiffer, Norbert; Mackey, David A; Hammond, Christopher J; Cheng, Ching-Yu; Craig, Jamie E; Rabinowitz, Yaron S; Wiggs, Janey L; Burdon, Kathryn P; van Duijn, Cornelia M; MacGregor, Stuart

2018-05-14

Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related pathways, pathway analyses uncover previously unreported gene sets. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1, ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), and the LUM-DCN-KERA gene complex involved in myopia, corneal dystrophies and cornea plana. Using index CCT-increasing variants, we find a significant inverse correlation in effect sizes between CCT and keratoconus (r = -0.62, P = 5.30 × 10 -5 ) but not between CCT and primary open-angle glaucoma (r = -0.17, P = 0.2). Our findings provide evidence for shared genetic influences between CCT and keratoconus, and implicate candidate genes acting in collagen and extracellular matrix regulation.

Volumetric graphics in liquid using holographic femtosecond laser pulse excitations

NASA Astrophysics Data System (ADS)

Kumagai, Kota; Hayasaki, Yoshio

2017-06-01

Much attention has been paid to the development of three-dimensional volumetric displays in the fields of optics and computer graphics, and it is a dream of we display researchers. However, full-color volumetric displays are challenging because many voxels with different colors have to be formed to render volumetric graphics in real three-dimensional space. Here, we show a new volumetric display in which microbubble voxels are three-dimensionally generated in a liquid by focused femtosecond laser pulses. Use of a high-viscosity liquid, which is the key idea of this system, slows down the movement of the microbubbles, and as a result, volumetric graphics can be displayed. This "volumetric bubble display" has a wide viewing angle and simple refresh and requires no addressing wires because it involves optical access to transparent liquid and achieves full-color graphics composed on light-scattering voxels controlled by illumination light sources. In addition, a bursting of bubble graphics system using an ultrasonic vibrator also has been demonstrated. This technology will open up a wide range of applications in three-dimensional displays, augmented reality and computer graphics.

Processing parameters for filament winding thick-section PEEK/carbon fiber composites

NASA Astrophysics Data System (ADS)

Colton, J.; Leach, D.

1992-12-01

The consolidation pressure and winding speed for thermoplastic filament winding were studied. Thermoplastic composite parts were manufactured from tape prepreg (APC-2); powder-coated, semi-consolidated towpreg; and commingled fiber towpreg. The material used was carbon fiber (AS-4) (60 vol pct) in a PEEK matrix. The parts made were open-ended cylinders of the three materials, 177.8-mm ID, 228.6 mm long, 17 plies thick with a 0 deg lay-up angle; and rings, 50 plies of APC-2 thick, 6.35 mm wide (one strip wide), 177.8-mm ID, and a lay-up of 0 deg. Their quality was determined by surface finish and void percentage. The tubes made from APC-2 appeared to have the best quality of the three prepregs. For the rings, the speed of lay-down had a significant effect on both the final width of the parts and on the percentage of voids. The pressure of the roller had a significant effect on the final widths at a 99 percent confidence level, but a significant effect on the percentage of voids at only a 95 percent confidence level.

Processing parameters for thermoplastic filament winding

NASA Astrophysics Data System (ADS)

Colton, J.; Leach, D.

The consolidation pressure and winding speed for thermoplastic filament winding were studied. Thermoplastic composite parts were manufactured from tape prepreg (APC-2); powder-coated, semiconsolidated towpreg; and commingled fiber towpeg. The material used was carbon fiber (AS-4) (60 vol pct) in a PEEK matrix. The parts made were open-ended cylinders of the three materials, 177.8 mmID, 228.6 mm long, 17 plies thick with a 0 deg lay-up angle; and rings, 50 plies of APC-2 thick, 6.35 mm wide (one strip wide), 177.8 mm ID, and a lay-up of 0 deg. Their quality was determined by surface finish and void percentage. The tubes made from APC-2 appeared to have the best quality of the three prepregs. For the rings, the speed of lay down had a significant effect on both the final width of the parts and on the percentage of voids. The pressure of the roller had a significant effect on the final widths at a 99 percent confidence level, but only a significant effect on the percentage of voids at a 95 percent confidence level.

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

Incident Angle of Saltating Particles in Wind-Blown Sand

PubMed Central

Fu, Lin-Tao; Bo, Tian-Li; Gu, Hai-Hua; Zheng, Xiao-Jing

2013-01-01

Incident angle of saltating particles plays a very important role in aeolian events. In this paper, the incident angles of sand particles near the sand bed were measured in wind tunnel. It reveals that the incident angles range widely from 0° to 180° and thereby the means of angles are larger than published data. Surprisingly, it is found the proportion that angles of 5°–15° occupy is far below previous reports. The measuring height is probably the most important reason for the measurement differences between this study and previous investigations. PMID:23874470

Ocular surface disease incidence in patients with open-angle glaucoma.

PubMed

Radenković, Marija; Stanković-Babić, Gordana; Jovanović, Predrag; Djordjević-Jocić, Jasmina; Trenkić-Božinović, Marija

2016-01-01

Ocular surface disease (OSD) is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbances, tear film instability with potential damage to the ocular surface, accompanied by increased tear film osmolarity and inflammation of the ocular surface. It is a consequence of disrupted homeostasis of lacrimal functional unit. The main pathogenetic mechanism stems from tear hyperosmolarity and tear film instability. The etiological classification is hyposecretory (Sy-Sjögren and non-Sjögren) and evaporative (extrinsic and intrinsic) form. Delphi panel classification grades disease stages. Antiglaucoma topical therapy causes exacerbation or occurrence of symptoms of dry eye due to main ingredients or preservatives (benzalkonium chloride – BAK), which are dose- and time-dependent. BAK reduces the stability of the lipid layer of tears, the number of goblet cells, induces apoptosis and inflammatory infiltration. The aim of this study was the analysis of the OSD incidence in open-angle glaucoma patients caused by topical medicamentous therapy. Retrospective analysis of examined patients with open-angle glaucoma was used. Increased incidence of moderate and advanced OSD Index degrees in the group of primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma. According to the Delphi Panel Scale the most common grade is IIb (POAG and pseudoexfoliative glaucoma). Evaporative form of OSD prevailed in all treatment groups. High percentage of dry eye in patients with higher concentrations of preservatives applied was noticed. OSD should be timely diagnosed and treated. Dry eye has an impact on surgical outcome and postoperative visual acuity, and in order to improve patient compliance and quality of life, symptoms of dry eye should be addressed and medications with lower concentrations of preservatives should be applied.

Open wedge high tibial osteotomy using three-dimensional printed models: Experimental analysis using porcine bone.

PubMed

Kwun, Jun-Dae; Kim, Hee-June; Park, Jaeyoung; Park, Il-Hyung; Kyung, Hee-Soo

2017-01-01

The purpose of this study was to evaluate the usefulness of three-dimensional (3D) printed models for open wedge high tibial osteotomy (HTO) in porcine bone. Computed tomography (CT) images were obtained from 10 porcine knees and 3D imaging was planned using the 3D-Slicer program. The osteotomy line was drawn from the three centimeters below the medial tibial plateau to the proximal end of the fibular head. Then the osteotomy gap was opened until the mechanical axis line was 62.5% from the medial border along the width of the tibial plateau, maintaining the posterior tibial slope angle. The wedge-shaped 3D-printed model was designed with the measured angle and osteotomy section and was produced by the 3D printer. The open wedge HTO surgery was reproduced in porcine bone using the 3D-printed model and the osteotomy site was fixed with a plate. Accuracy of osteotomy and posterior tibial slope was evaluated after the osteotomy. The mean mechanical axis line on the tibial plateau was 61.8±1.5% from the medial tibia. There was no statistically significant difference (P=0.160). The planned and post-osteotomy correction wedge angles were 11.5±3.2° and 11.4±3.3°, and the posterior tibial slope angle was 11.2±2.2° pre-osteotomy and 11.4±2.5° post-osteotomy. There were no significant differences (P=0.854 and P=0.429, respectively). This study showed that good results could be obtained in high tibial osteotomy by using 3D printed models of porcine legs. Copyright © 2016 Elsevier B.V. All rights reserved.

Changes in the retrobulbar arterial circulation after decrease of the elevated intraocular pressure in men and women with primary open angle glaucoma.

PubMed

Marjanović, Ivan; Martinez, Antonio; Marjanović, Marija; Kontić, Djordje; Hentova-Senćanić, Paraskeva; Marković, Vujica; Bozić, Marija

2013-01-01

An altered perfusion of the optic nerve head has been proposed as a pathogenic factor of glaucoma. The aim of this study was to evaluate the changes of the hemodynamic parameters in the retrobulbar arterial circulation after decrease of the elevated intraocular pressure (IOP) in women and men with primary open angle glaucoma. The study included 60 patients (33 males and 27 females) older than 50 years, with diagnosed and treated primary open angle glaucoma (77 eyes of 39 patients had increased IOP, > 25 mm Hg).They were examined at the Clinic of Eye Diseases (complete ophthalmologic exam) and Clinic of Neurology, Clinical Center of Serbia, Belgrade, from December 2009 to December 2010. Imaging of hemodynamic parameters of three retrobulbar arterial vessels: ophthalmic, central retinal and posterior ciliary arteries with color Doppler was performed. Among women, hemodynamic arterial parameter of the peak-systolic velocity was increased in the central retinal artery and decreased in the ophthalmic artery and posterior ciliary arteries; end-diastolic velocity was increased in all three retrobulbar vascular levels; Pourcelot resistivity index was increased, but pulsatility index was decreased in all three vessels. Among men, peak-systolic velocity, end-diastolic velocity and pulsatility index were decreased in all three vessels; resistivity index was increased in the ophthalmic artery, but decreased in the central retinal artery and posterior ciliary arteries. There was a significant change of the ophthalmic artery pulsatility index in women, and the end-diastolic velocity of the ophthalmic artery in men. There was a difference of the retrobulbar arterial circulation between women and men with primary open angle glaucoma after decrease of the elevated intraocular pressure.The role of vascular factors in the supply of the optic disc neuroretinal rim is important.

Angle amplifier based on multiplexed volume holographic gratings

NASA Astrophysics Data System (ADS)

Cao, Liangcai; Zhao, Yifei; He, Qingsheng; Jin, Guofan

2008-03-01

Angle amplifier of laser beam scanner is a widely used device in optical systems. Volume holographic optical elements can be applied in the angle amplifier. Compared with the traditional angle amplifier, it has the advantages of high angle resolution, high diffraction efficiency, small size, and high angle magnification and flexible design. Bragg anglewavelength- compensating recording method is introduced. Because of the Bragg compensatory relation between angle and wavelength, this device could be recorded at another wavelength. The design of the angle amplifier recording at the wavelength of 514.2nm for the working wavelength of 632.8nm is described. An optical setup for recording the angle amplifier device is designed and discussed. Experimental results in the photorefractive crystal Fe:LiNbO 3 demonstrate the feasibility of the angle amplifier scheme.

Effects of flow-path variations on internal reversing flow in a tailpipe offtake configuration for ASTOVL aircraft

NASA Technical Reports Server (NTRS)

Mcardle, Jack G.; Esker, Barbara S.

1993-01-01

A one-third-scale model of a generic tailpipe offtake system for an advanced short takeoff, vertical landing (ASTOVL) aircraft was tested at the NASA Lewis Research Center Powered Lift Facility. The basic model consisted of a tailpipe with a center body to form an annulus simulating turbine outflow with no swirl; twin offtake ducts with elbows at the ends to turn the flow to a downward direction; flow control nozzles at the ends of the elbows; and a blind flange at the end of the tailpipe to simulate a closed cruise nozzle. The offtake duct-to-tailpipe diameter ratio was 0.74. Modifications of a generic nature were then made to this basic configuration to measure the effects of flow-path changes on the flow and pressure-loss characteristics. The modifications included adding rounded entrances at the forward edges of the offtake openings, blocking the tailpipe just aft the openings instead of at the cruise nozzle, changing the location of the openings along the tailpipe, removing the center body, and varying the Mach number (flow rate) over a wide range in the tailpipe ahead of the openings by changing the size of the flow control nozzles. The tests were made with unheated air at tailpipe-to-ambient pressure ratios from 1.4 to 5. Results are presented and compared with performance graphs, total-pressure contour plots, paint streak flow visualization photographs, and a flow-angle probe traverse at the offtake entrance.

Microstructure of Amorphous and Semi-Crystalline Polymers.

DTIC Science & Technology

1981-06-07

of these materials. Further, the occurrence of nodular structures is difficult to reconcile with the results of studies of small angle neutron ...scattering and small angle neutron scattering studies of the same materials. Based on the combined results of these studies , it is suggested that the nodular...relevance here were reviewed by Flory.’ In addition to these, the results of studies using small angle neutron scattering’ and wide angle X-ray scattering

Hip arthroscopy versus open surgical dislocation for femoroacetabular impingement

PubMed Central

Zhang, Dagang; Chen, Long; Wang, Guanglin

2016-01-01

Abstract Background: This meta-analysis aims to evaluate the efficacy and safety of hip arthroscopy versus open surgical dislocation for treating femoroacetabular impingement (FAI) through published clinical trials. Methods: We conducted a comprehensive literature search using PUBMED, EMBASE, and the Cochrane Central Register of Controlled Trials databases for relevant studies on hip arthroscopy and open surgical dislocation as treatment options for FAI. Results: Compared with open surgical dislocation, hip arthroscopy resulted in significantly higher Nonarthritic Hip Scores (NAHS) at 3- and 12-month follow-ups, a significant improvement in NAHS from preoperation to 3 months postoperation, and a significantly lower reoperation rate. Open surgical dislocation resulted in a significantly improved alpha angle by the Dunn view in patients with cam osteoplasty from preoperation to postoperation, compared with hip arthroscopy. This meta-analysis demonstrated no significant differences in the modified Harris Hip Score, Hip Outcome Score-Activities of Daily Living, or Hip Outcome Score-Sport Specific Subscale at 12 months of follow-up, or in complications (including nerve damage, wound infection, and wound dehiscence). Conclusion: Hip arthroscopy resulted in higher NAHS and lower reoperation rates, but had less improvement in alpha angle in patients with cam osteoplasty, than open surgical dislocation. PMID:27741133

The Opening of the Arctic: Establishing a New Security Perimeter for the United States

DTIC Science & Technology

2013-02-14

Eastern oil is projected to come to an end by 2032. British Petroleum, in its annual energy outlook, predicts growth in biofuel supplies and...Inclination angles for GPS and Galileo satellites are 55 and 56 degrees respectively while GLONASS inclination angles are marginally better at 65

Miniaturized haploscope for testing binocular vision

NASA Technical Reports Server (NTRS)

Decker, T. A.

1973-01-01

Device can reproduce virtually all binocular stimulus conditions (target configuration, vergence angle, and accommodative distance) used to test binocular performance. All subsystems of electronic controls are open-loop and solid-state-controlled and, with the exception of vergence angle drive, utilize dc stepping motors as prime movers. Arrangement is also made for readouts of each variable.

Geostationary Coastal and Air Pollution Events (GeoCAPE) Wide Angle Spectrometer (WAS)

NASA Technical Reports Server (NTRS)

Kotecki, Carl; Chu, Martha; Mannino, Antonio; Marx, Catherine Trout; Bowers, Gregory A.; Bolognese, Jeffrey A.; Matson, Elizabeth A.; McBirney, Thomas R.; Earle, Cleland P.; Choi, Michael K.;

Monitoring the recrystallisation of amorphous xylitol using Raman spectroscopy and wide-angle X-ray scattering.

PubMed

Palomäki, Emmi; Ahvenainen, Patrik; Ehlers, Henrik; Svedström, Kirsi; Huotari, Simo; Yliruusi, Jouko

2016-07-11

In this paper we present a fast model system for monitoring the recrystallization of quench-cooled amorphous xylitol using Raman spectroscopy and wide-angle X-ray scattering. The use of these two methods enables comparison between surface and bulk crystallization. Non-ordered mesoporous silica micro-particles were added to the system in order to alter the rate of crystallization of the amorphous xylitol. Raman measurements showed that adding silica to the system increased the rate of surface crystallization, while X-ray measurements showed that the rate of bulk crystallization decreased. Using this model system it is possible to measure fast changes, which occur in minutes or within a few hours. Raman-spectroscopy and wide-angle X-ray scattering were found to be complementary techniques when assessing surface and bulk crystallization of amorphous xylitol. Copyright © 2016 Elsevier B.V. All rights reserved.

Wide-angle display developments by computer graphics

NASA Technical Reports Server (NTRS)

Fetter, William A.

1989-01-01

Computer graphics can now expand its new subset, wide-angle projection, to be as significant a generic capability as computer graphics itself. Some prior work in computer graphics is presented which leads to an attractive further subset of wide-angle projection, called hemispheric projection, to be a major communication media. Hemispheric film systems have long been present and such computer graphics systems are in use in simulators. This is the leading edge of capabilities which should ultimately be as ubiquitous as CRTs (cathode-ray tubes). These assertions are not from degrees in science or only from a degree in graphic design, but in a history of computer graphics innovations, laying groundwork by demonstration. The author believes that it is timely to look at several development strategies, since hemispheric projection is now at a point comparable to the early stages of computer graphics, requiring similar patterns of development again.

Based on graphene tunable dual-band terahertz metamaterial absorber with wide-angle

NASA Astrophysics Data System (ADS)

Huang, Mulin; Cheng, Yongzhi; Cheng, Zhengze; Chen, Haoran; Mao, Xuesong; Gong, Rongzhou

2018-05-01

We present a wide-angle tunable dual-band terahertz (THz) metamaterial absorber (MMA) based on square graphene patch (SGP). This MMA is a simple periodic array, consisting of a dielectric substrate sandwiched with the SGP and a continuous metallic film. The designed MMA can achieve dual-band absorption by exciting fundamental and second higher-order resonance modes on SGP. The numerical simulations indicate that the absorption spectrum of the designed MMA is tuned from 0.85 THz to 1.01 THz, and from 2.84 THz to 3.37 THz when the chemical potential of the SGP is increasing from 0.4eV to 0.8eV. Moreover, it operates well in a wide-angle of the incident waves. The presented THz MMA based on the SGP could find some potential applications in optoelectronic related devices, such as sensor, emitter and wavelength selective radiators.

Assessment of crustal velocity models using seismic refraction and reflection tomography

NASA Astrophysics Data System (ADS)

Zelt, Colin A.; Sain, Kalachand; Naumenko, Julia V.; Sawyer, Dale S.

2003-06-01

Two tomographic methods for assessing velocity models obtained from wide-angle seismic traveltime data are presented through four case studies. The modelling/inversion of wide-angle traveltimes usually involves some aspects that are quite subjective. For example: (1) identifying and including later phases that are often difficult to pick within the seismic coda, (2) assigning specific layers to arrivals, (3) incorporating pre-conceived structure not specifically required by the data and (4) selecting a model parametrization. These steps are applied to maximize model constraint and minimize model non-uniqueness. However, these steps may cause the overall approach to appear ad hoc, and thereby diminish the credibility of the final model. The effect of these subjective choices can largely be addressed by estimating the minimum model structure required by the least subjective portion of the wide-angle data set: the first-arrival times. For data sets with Moho reflections, the tomographic velocity model can be used to invert the PmP times for a minimum-structure Moho. In this way, crustal velocity and Moho models can be obtained that require the least amount of subjective input, and the model structure that is required by the wide-angle data with a high degree of certainty can be differentiated from structure that is merely consistent with the data. The tomographic models are not intended to supersede the preferred models, since the latter model is typically better resolved and more interpretable. This form of tomographic assessment is intended to lend credibility to model features common to the tomographic and preferred models. Four case studies are presented in which a preferred model was derived using one or more of the subjective steps described above. This was followed by conventional first-arrival and reflection traveltime tomography using a finely gridded model parametrization to derive smooth, minimum-structure models. The case studies are from the SE Canadian Cordillera across the Rocky Mountain Trench, central India across the Narmada-Son lineament, the Iberia margin across the Galicia Bank, and the central Chilean margin across the Valparaiso Basin and a subducting seamount. These case studies span the range of modern wide-angle experiments and data sets in terms of shot-receiver spacing, marine and land acquisition, lateral heterogeneity of the study area, and availability of wide-angle reflections and coincident near-vertical reflection data. The results are surprising given the amount of structure in the smooth, tomographically derived models that is consistent with the more subjectively derived models. The results show that exploiting the complementary nature of the subjective and tomographic approaches is an effective strategy for the analysis of wide-angle traveltime data.

Disturbance Detection in Snow Using Polarimetric Imagery of the Visible Spectrum

DTIC Science & Technology

2010-12-01

37 1. Wide- Angle Image .............................................................................37 2. Telephoto Lens Image...known qualitative results regarding polarization is that of Brewster’s angle . Sir David Brewster , a self-taught scientist and inventor, was deeply...refractive indices of materials in which they traversed ( Brewster , 1815). Coulson accurately defines Brewster’s angle : Light which is reflected at a

[Results of the ocular hypertension treatment study and the confocal scanning laser ophthalmoscopy ancillary study and evaluation of the heidelberg retina tomograph].

PubMed

Klatt, K; Schmidt, E; Scheuerle, A F

2008-04-01

The Ocular Hypertension Treatment Study (OHTS) has shown that analyzing changes of the optic disc configuration is superior to evaluating visual field findings for the early detection of primary open angle glaucoma. The Confocal Scanning Laser Ophthalmoscopy Ancillary Study (CSLO) is the first study to reveal that certain topographic baseline measurements of the optic disc are significantly associated with the development of primary open angle glaucoma in patients with ocular hypertension. An abnormally increased "mean height contour" value proved to be the individual parameter connected with the highest risk. The reliability of the Moorfields Regression Analysis of certain individual sectors during early detection of a primary angle glaucoma is higher than that of the global measurement. The temporal superior and inferior as well as the nasal inferior sectors have the highest positive predictive values and the largest risks in both univariate and multivariate analysis.

Fixed combination of bimatoprost and timolol in patients with primary open-angle glaucoma or ocular hypertension with inadequate IOP adjustment

PubMed Central

Brief, Gerrett; Lammich, Tobias; Nagel, Edgar; Pfennigsdorf, Sabine; Spraul, Christoph W; Ho, Selwyn

2010-01-01

Objective To assess the efficacy and tolerability of a fixed combination of bimatoprost and timolol (BTFC) in a large patient sample in a clinical setting. Methods In this multicenter, observational, noncontrolled, open-label study, patients (n = 1862) with primary open-angle glaucoma or ocular hypertension were treated with BTFC. Assessments were made at baseline, six weeks, and three months. Results Prior to starting BTFC, 92.3% of patients were taking other ocular hypotensive medications. In the overall group at three months, mean intraocular pressure was reduced from baseline (21.7 ± 4.5 mmHg and 21.8 ± 4.9 mmHg for the right and left eye, respectively) to 16.1 ± 3.0 mmHg for each eye (P < 0.0001). The majority of patients (92%) reported no adverse events. The most commonly reported adverse events (in >1% of patients) were eye irritation, and ocular and conjunctival hyperemia. Adherence to treatment was generally better than (35.4%) or the same as (57.5%) with prior therapy. BTFC tolerability was rated as excellent or good by 92.3% of physicians and 85.8% of patients. Conclusions In a large group of patients with primary open-angle glaucoma or ocular hypertension, treatment with BTFC was associated with consistent reductions in IOP, improved adherence to treatment, and good tolerability. PMID:20957059

Geometry and Kinematics of Fault-Propagation Folds with Variable Interlimb Angles

NASA Astrophysics Data System (ADS)

Dhont, D.; Jabbour, M.; Hervouet, Y.; Deroin, J.

2009-12-01

Fault-propagation folds are common features in foreland basins and fold-and-thrust belts. Several conceptual models have been proposed to account for their geometry and kinematics. It is generally accepted that the shape of fault-propagation folds depends directly from both the amount of displacement along the basal decollement level and the dip angle of the ramp. Among these, the variable interlimb angle model proposed by Mitra (1990) is based on a folding kinematics that is able to explain open and close natural folds. However, the application of this model is limited because the geometric evolution and thickness variation of the fold directly depend on imposed parameters such as the maximal value of the ramp height. Here, we use the ramp and the interlimb angles as input data to develop a forward fold modelling accounting for thickness variations in the forelimb. The relationship between the fold amplitude and fold wavelength are subsequently applied to build balanced geologic cross-sections from surface parameters only, and to propose a kinematic restoration of the folding through time. We considered three natural examples to validate the variable interlimb angle model. Observed thickness variations in the forelimb of the Turner Valley anticline in the Alberta foothills of Canada precisely correspond to the theoretical values proposed by our model. Deep reconstruction of the Alima anticline in the southern Tunisian Atlas implies that the decollement level is localized in the Triassic-Liassic series, as highlighted by seismic imaging. Our kinematic reconstruction of the Ucero anticline in the Spanish Castilian mountains is also in agreement with the anticline geometry derived from two cross-sections. The variable interlimb angle model implies that the fault-propagation fold can be symmetric, normal asymmetric (with a greater dip value in the forelimb than in the backlimb), or reversely asymmetric (with greater dip in the backlimb) depending on the shortening amount. This model allows also: (i) to easily explain folds with wide variety of geometries; (ii) to understand the deep architecture of anticlines; and (iii) to deduce the kinematic evolution of folding with time. Mitra, S., 1990, Fault-propagation folds: geometry, kinematic evolution, and hydrocarbon traps. AAPG Bulletin, v. 74, no. 6, p. 921-945.

Biomimetic artificial Si compound eye surface structures with broadband and wide-angle antireflection properties for Si-based optoelectronic applications

NASA Astrophysics Data System (ADS)

Leem, Jung Woo; Song, Young Min; Yu, Jae Su

2013-10-01

We report the biomimetic artificial silicon (Si) compound eye structures for broadband and wide-angle antireflection by integrating nanostructures (NSs) into periodically patterned microstructures (p-MSs) via thermal dewetting of gold and subsequent dry etching. The truncated cone microstructures with a two-dimensional hexagonal symmetry pattern were fabricated by photolithography and dry etching processes. The desirable shape and density of the nanostructures were obtained by controlled dewetting. The incorporation of p-MSs into the NS/Si surface further reduced the surface total reflectance over a wide wavelength range of 300-1030 nm at near normal incidence, indicating the average reflectance (Ravg) and solar weighted reflectance (RSWR) values of ~2.5% and 2%, respectively, compared to the only NSs on the flat Si surface (i.e., Ravg ~ 4.9% and RSWR ~ 4.5%). Additionally, the resulting structure improved the angle-dependent antireflection property due to its relatively omnidirectional shape, which exhibited the Ravg < 4.3% and RSWR < 3.7% in the wavelength region of 300-1100 nm even at a high incident light angle of 70° in the specular reflectance.We report the biomimetic artificial silicon (Si) compound eye structures for broadband and wide-angle antireflection by integrating nanostructures (NSs) into periodically patterned microstructures (p-MSs) via thermal dewetting of gold and subsequent dry etching. The truncated cone microstructures with a two-dimensional hexagonal symmetry pattern were fabricated by photolithography and dry etching processes. The desirable shape and density of the nanostructures were obtained by controlled dewetting. The incorporation of p-MSs into the NS/Si surface further reduced the surface total reflectance over a wide wavelength range of 300-1030 nm at near normal incidence, indicating the average reflectance (Ravg) and solar weighted reflectance (RSWR) values of ~2.5% and 2%, respectively, compared to the only NSs on the flat Si surface (i.e., Ravg ~ 4.9% and RSWR ~ 4.5%). Additionally, the resulting structure improved the angle-dependent antireflection property due to its relatively omnidirectional shape, which exhibited the Ravg < 4.3% and RSWR < 3.7% in the wavelength region of 300-1100 nm even at a high incident light angle of 70° in the specular reflectance. Electronic supplementary information (ESI) available: See DOI: 10.1039/c3nr02806b

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geltman, S.

Recent measurements on CO{sub 2}-laser-assisted electron-atom collisions have shown large inconsistencies with the Kroll-Watson formula for small-angle scattering. We have carried out a detailed study to compare the predictions of Kroll-Watson theory (for both single and multimode fields) with those of conventional perturbation theory for stimulated free-free transitions. It is found that for {ital E}{sub 0}/2{omega}{sup 2}{lt}1, where perturbation theory is valid, there are large differences with the Kroll-Watson theory. Comparisons of experimental variations with respect to scattering angle and electron energy show much better agreement with perturbation theory than with Kroll-Watson theory. A study of the angular variations inmore » perturbation theory shows that use of the {open_quote}{open_quote}outgoing{close_quote}{close_quote} wave final state gives much better agreement with experiment than does the {open_quote}{open_quote}ingoing{close_quote}{close_quote} wave final state, which is different from the choice made in early bremsstrahlung theory. {copyright} {ital 1996 The American Physical Society.}« less

Anterior chamber angle assessment using gonioscopy and ultrasound biomicroscopy.

PubMed

Narayanaswamy, Arun; Vijaya, Lingam; Shantha, B; Baskaran, Mani; Sathidevi, A V; Baluswamy, Sukumar

2004-01-01

Comparison of anterior chamber angle measurements using ultrasound biomicroscopy (UBM) and gonioscopy. Five hundred subjects were evaluated for grading of angle width by the Shaffer method. UBM was done in the same group to document angle width, angle opening distance (AOD 500), and anterior chamber depth. Biometric parameters were documented in all subjects. UBM and gonioscopic findings were compared. A study was conducted in 282 men and 218 women with a mean age of 57.32 +/- 12.48 years. Gonioscopic grading was used to segregate occludable (slit-like, grades 1 and 2) from nonoccludable (grades 3 and 4) angles. Subjective assessment by gonioscopy resulted in an overestimation of angle width within the occludable group when compared with values obtained by UBM. This did not affect the segregation of occludable versus nonoccludable angles by gonioscopy. Biometric parameters in eyes with occludable angles were significantly lower in comparison with eyes with nonoccludable angles, except for lens thickness. AOD 500 correlated well with angle width. We concluded that clinical segregation into occludable and nonoccludable angles by an experienced observer using gonioscopy is fairly accurate. However, UBM is required for objective quantification of angles, and AOD 500 can be a reliable and standard parameter to grade angle width.

Camouflage of a high-angle skeletal Class II open-bite malocclusion in an adult after mini-implant failure during treatment.

PubMed

Franzotti Sant'Anna, Eduardo; Carneiro da Cunha, Amanda; Paludo Brunetto, Daniel; Franzotti Sant'Anna, Claudia

2017-03-01

The treatment of skeletal anterior open-bite malocclusion requires complex orthodontic planning that considers its multifactorial etiology, treatment limitations, and high relapse rates. This case report illustrates a successful treatment approach for a skeletal high-angle Class II malocclusion in an adult with a severe open bite. The treatment consisted of a high-pull headgear therapy after mini-implants failure during fixed orthodontic therapy. Adequate esthetics and function were achieved. Despite its low probability, the unexpected event of mini-implant loosening during complex treatments should be considered. Therefore, classic orthodontic mechanics should be established, especially when treating patients for whom invasive procedures such as miniplates or orthognathic surgery are not available options. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

MARGATS cruise: investigation of the deep internal structure and the heterogeneous margins of the Demerara plateau reveals a polyphased volcanic history

NASA Astrophysics Data System (ADS)

Graindorge, D.; Museur, T.; Roest, W. R.; Klingelhoefer, F.; Loncke, L.; Basile, C.; Poetisi, E.; Deverchere, J.; Heuret, A.; Jean-Frederic, L.; Perrot, J.

2017-12-01

The MARGATS scientific cruise was carried out from October 20th to November 16th 2016 on board the R/V L'Atalante, offshore Suriname and French Guiana. This cruise is part of a program dedicated to the geological investigation of the continental margin, including the Demerara plateau, following the GUYAPLAC (2003), IGUANES (2013) and DRADEM (2016) cruises. The aim of MARGATS was to image the internal structure of the Demerara plateau and its different margins using coincident deep penetrating wide angle refraction and multi channel reflection seismic (MCS) methods. During the MARGATS experiment 171 OBS deployments were distributed along 4 wide-angle lines. Along each wide-angle line we also recorded coincident MCS data using a 3 km long 480 channel streamer. The dataset was completed by three MCS lines along the eastern part of the Demerara plateau. MCS MAR007 line which is coincident with line OBS MAR-3 was extended on land by 13 land stations deployed along the Maroni River. This line, together with MCS MAR001 and the coincident OBS MAR-1 line reveal the highly homogeneous deep structure of the internal part of the plateau. MCS MAR005 line, which is coincident with OBS MAR-2, MCS MAR006 line coincident with OBS MAR-4, MCS MAR002, MCS MAR003 and MCS MAR004 helps to elucidate the structural complexity of the northern transform margin and the eastern divergent margin of the plateau. These new datasets are highly complementary to the DRADEM dredge results which provide evidence for mid Jurassic volcanic rocks along the plateau and significant vertical displacements along the transform margin. These results allow to interpret the plateau as the remains of a huge jurassic volcanic divergent margin along the Central Atlantic ocean to the west, possibly remobilized during the cretaceous opening of the Equatorial Atlantic ocean as an highly oblique margin to the north and a divergent margin to the east in persistent presence of volcanism. This AGU session will be a great opportunity to present the exceptional quality of the seismic data, after the initial processing steps and how these data are conditioning a new understanding of the Demarara plateau and its margins which implies the hypothetic role of a new hot spot shaping the complex polyphased history of the structure.

Entry, Descent, and Landing Guidance and Control Approaches to Satisfy Mars Human Mission Landing Criteria

NASA Technical Reports Server (NTRS)

Dwyer Cianciolo, Alicia; Powell, Richard W.

2017-01-01

Precision landing on Mars is a challenge. All Mars lander missions prior to the 2012 Mars Science Laboratory (MSL) had landing location uncertainty ellipses on the order of hundreds of kilometers. Sending humans to the surface of Mars will likely require multiple landers delivered in close proximity, which will in turn require orders of magnitude improvement in landing accuracy. MSL was the first Mars mission to use an Apollo-derived bank angle guidance to reduce the size of the landing ellipse. It utilized commanded bank angle magnitude to control total range and bank angle reversals to control cross range. A shortcoming of this bank angle guidance is that the open loop phase of flight created by use of bank reversals increases targeting errors. This paper presents a comparison of entry, descent and landing performance for a vehicle with a low lift-to-drag ratio using both bank angle control and an alternative guidance called Direct Force Control (DFC). DFC eliminates the open loop flight errors by directly controlling two forces independently, lift and side force. This permits independent control of down range and cross range. Performance results, evaluated using the Program to Optimize Simulated Trajectories (POST2), including propellant use and landing accuracy, are presented.

Agreement between gonioscopy and ultrasound biomicroscopy in detecting iridotrabecular apposition.

PubMed

Barkana, Yaniv; Dorairaj, Syril K; Gerber, Yariv; Liebmann, Jeffrey M; Ritch, Robert

2007-10-01

To assess the agreement between findings obtained at dark-room gonioscopy and ultrasound biomicroscopy (UBM) in the diagnosis of iridotrabecular apposition in light and dark conditions. We enrolled patients with appositional angle closure at dark-room gonioscopy performed using a 1-mm slitlamp beam that did not cross the pupil. Ultrasound biomicroscopic images were acquired in normal room light and subsequently with all room lights off. Images were evaluated for the presence or absence of iris-cornea contact. The angle opening distance at 500 microm was calculated. Iridotrabecular apposition in at least 1 angle quadrant was demonstrated in all 18 eyes at dark-room gonioscopy, 17 eyes (94%) at dark-room UBM, and only 10 eyes (56%) at UBM in room light. Of 18 superior angles that were appositionally closed at dark-room gonioscopy, apposition was demonstrated on UBM images in 16 (89%) in a dark room but only 6 (33%) in room light. Angle opening distance was less during dark-room gonioscopy in all but the nasal quadrant. We found high agreement between gonioscopy and UBM when both are performed in a completely dark room. Our findings support the recommendation that, in routine clinical practice, gonioscopy be performed in a dark room to avoid misdiagnosis of treatable iridotrabecular apposition.

A mathematical method for precisely calculating the radiographic angles of the cup after total hip arthroplasty.

PubMed

Zhao, Jing-Xin; Su, Xiu-Yun; Xiao, Ruo-Xiu; Zhao, Zhe; Zhang, Li-Hai; Zhang, Li-Cheng; Tang, Pei-Fu

2016-11-01

We established a mathematical method to precisely calculate the radiographic anteversion (RA) and radiographic inclination (RI) angles of the acetabular cup based on anterior-posterior (AP) pelvic radiographs after total hip arthroplasty. Using Mathematica software, a mathematical model for an oblique cone was established to simulate how AP pelvic radiographs are obtained and to address the relationship between the two-dimensional and three-dimensional geometry of the opening circle of the cup. In this model, the vertex was the X-ray beam source, and the generatrix was the ellipse in radiographs projected from the opening circle of the acetabular cup. Using this model, we established a series of mathematical formulas to reveal the differences between the true RA and RI cup angles and the measurements results achieved using traditional methods and AP pelvic radiographs and to precisely calculate the RA and RI cup angles based on post-operative AP pelvic radiographs. Statistical analysis indicated that traditional methods should be used with caution if traditional measurements methods are used to calculate the RA and RI cup angles with AP pelvic radiograph. The entire calculation process could be performed by an orthopedic surgeon with mathematical knowledge of basic matrix and vector equations. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Handling Qualities of a Capsule Spacecraft During Atmospheric Entry

NASA Technical Reports Server (NTRS)

Bilimoria, Karl D.; Mueller, Eric R.

2010-01-01

A piloted simulation was conducted to study handling qualities for capsule spacecraft entering the Earth s atmosphere. Eight evaluation pilots, including six pilot astronauts, provided Cooper-Harper ratings, workload ratings, and qualitative comments. The simulation began after descending through the atmospheric entry interface point and continued until the drogue parachutes deployed. There were two categories of piloting tasks, both of which required bank angle control. In one task category, the pilot followed a closed-loop bank angle command computed by the backup guidance system to manage g-loads during entry. In the other task category, the pilot used intuitive rules to determine the desired bank angle independently, based on an open-loop schedule of vertical speed, Mach, and total energy specified at several range-to-target gates along the entry trajectory. Pilots were able to accurately track the bank angle guidance commands and steered the capsule toward the recovery site with essentially the same range error as the benchmark autopilot trajectory albeit with substantially higher propellant usage, and the handling qualities for this task were satisfactory. Another key result was that the complex piloting task of atmospheric entry could be performed satisfactorily, even in the presence of large dispersions, by controlling bank angle to follow a simple open-loop schedule.

HST Multicolor (255-1042 nm) Photometry of Saturn's Main Rings. 1; Radial Profiles, Phase and Opening Angle Variations, and Regional Spectra

NASA Technical Reports Server (NTRS)

Cuzzi, Jeffrey N.; French, Richard G.; Dones, Luke; DeVincenzi, Donald (Technical Monitor)

2001-01-01

The main rings of Saturn were observed with the Planetary Camera of the WFPC2 instrument on the Hubble Space Telescope (HST) from September 1996 to August 2000 as the'ring opening angle to Earth and Sun increased from 4 deg to 24 deg, with a spread of phase angles between 0.3 deg and 6 deg at each opening angle. The rings were routinely observed in the five HST wideband UBVRI filters (F336W, F439W, F555W, F675W, and F814W) and occasionally in the F255W, F785LP, and F1042M filters. The emphasis in this series of papers will be on radial color (implying compositional) variations. In this first paper we describe the analysis technique and calibration procedure, note revisions in a previously published Voyager ring color data analysis, and present new results based on over 100 HST images. In the 300-600 nm spectral range where the rings are red, the 555nm/336nm ratio increases by about 14% as the phase angle increases from 0.3 deg to 6 deg. This effect, never reported previously for the rings, is significantly larger than the phase reddening which characterizes other icy objects, primarily because of the redness of the rings. However, there is no discernible tendency for color to vary with ring opening angle at a given phase angle, and there is no phase variation of color where the spectrum is flat. We infer from this combination of facts that multiple intraparticle scattering, either in a regolith or between facets of an unusually rough surface, is important in these geometries, but that multiple interparticle scattering in a vertically extended layer is not. Voyager color ratios at a phase angle of 14 deg are compatible with this trend, but calibration uncertainties prevent their use in quantitative modeling. Overall ring-average spectra are compatible with those of earlier work within calibration uncertainties, but ring spectra vary noticeably with region. We refine and subdivide the regions previously defined by others. The variation seen between radial profiles of ratios between different wavelength suggests the presence of multiple compositional components with different radial distributions. We present new radial profiles of far UV color ratio (F336W/F255W) showing, substantial global variations having a different radial structure than seen between 555 and 336nm. We also find evidence for absorption in the 850nm spectral range (a feature previously only weakly indicated in ring-averaged spectra) primarily through its radial variation; it is located primarily in the C ring, where the particles are known to have lower albedo, and is consistent with "interplanetary pollution" of the rings.

Brightness discrimination test is not useful in screening for open angle glaucoma.

PubMed

Peter, E; Thomas, R; Muliyil, J

1996-06-01

Brightness discrimination test (BDT) is routinely employed to assess asymmetrical optic nerve dysfunction and has been suggested as a screening test for primary open angle glaucoma (POAG). We tested the reliability and validity of BDT in the diagnosis of POAG. The study groups included 34 patients with established primary open angle glaucoma, 20 glaucoma suspects, and 33 age-sex matched controls. Cataract was not an exclusion criterion in these groups. The normal brightness score was determined to be 88% (mean score, 94%-2 SD) in a pilot study. Brightness discrimination test was performed in all subjects by two observers independently. BDT showed an excellent interobserver agreement (weighted Kappa 0.84). The presence of a cataract alone increased the risk of brightness impairment twofold, glaucoma alone increased the risk eightfold, and the presence of both conditions by 17 times compared to those with neither condition. BDT was not a useful test in the diagnosis of POAG (sensitivity 67% and specificity 93%); the ability to detect a significant field defect was also poor (sensitivity 53% and specificity 76%). There was poor association between decreased brightness scores and asymmetrical field defects as determined by the Humphrey's field analyzer (HFA).

Characterizing the “POAGome”: A bioinformatics-driven approach to primary open-angle glaucoma

PubMed Central

Danford, Ian D.; Verkuil, Lana D.; Choi, Daniel J.; Collins, David W.; Gudiseva, Harini V.; Uyhazi, Katherine E.; Lau, Marisa K.; Kanu, Levi N.; Grant, Gregory R.; Chavali, Venkata R.M.; O’Brien, Joan M.

2017-01-01

Primary open-angle glaucoma (POAG) is a genetically, physiologically, and phenotypically complex neurodegenerative disorder. This study addressed the expanding collection of genes associated with POAG, referred to as the “POAGome.” We used bioinformatics tools to perform an extensive, systematic literature search and compiled 542 genes with confirmed associations with POAG and its related phenotypes (normal tension glaucoma, ocular hypertension, juvenile open-angle glaucoma, and primary congenital glaucoma). The genes were classified according to their associated ocular tissues and phenotypes, and functional annotation and pathway analyses were subsequently performed. Our study reveals that no single molecular pathway can encompass the pathophysiology of POAG. The analyses suggested that inflammation and senescence may play pivotal roles in both the development and perpetuation of the retinal ganglion cell degeneration seen in POAG. The TGF-β signaling pathway was repeatedly implicated in our analyses, suggesting that it may be an important contributor to the manifestation of POAG in the anterior and posterior segments of the globe. We propose a molecular model of POAG revolving around TGF-β signaling, which incorporates the roles of inflammation and senescence in this disease. Finally, we highlight emerging molecular therapies that show promise for treating POAG. PMID:28223208

Oxidative stress markers in patients with primary open-angle glaucoma.

PubMed

Ghanem, Asaad A; Arafa, Lamiaa F; El-Baz, Ayman

2010-04-01

To investigate the levels of antioxidant enzymes catalase (CAT), glutathione peroxidase (GPO), superoxide dismutase (SOD), and malondialdehyde (MDA) in human eyes with primary open-angle glaucoma (POAG) and to correlate their concentrations with severity of glaucoma. A prospective cases control study. Thirty patients with primary open-angle glaucoma and twenty-five patients with senile cataracts of matched age and gender were included in the study prospectively. Aqueous humor samples were obtained by paracentesis at the time of elective surgery for glaucomatous and cataractous patients. Aqueous humor were analyzed for CAT, GPO, SOD, and MDA status. GPO, SOD, and MDA enzyme levels revealed a high significant increase in aqueous humor of POAG patients with respect to the comparative group of cataract patients (P < 0.001). No significant difference in the activity of CAT enzyme in aqueous humor of POAG and cataract patient (P = 0.201). Significant correlation was found between the MDA enzyme level and severe visual field loss (P < 0.001) in POAG patients. Increased levels of aqueous humor GPO, SOD, and MDA may be associated with POAG. In addition, they may be useful antioxidant enzyme levels in aqueous humor of POAG patients as a result of glaucoma disease and not a cause.

Prospective, non-interventional, multicenter study of the intraocular pressure-lowering effects of prostaglandin analog/prostamide-containing therapies in previously treated patients with open-angle glaucoma or ocular hypertension

PubMed Central

Tamçelik, Nevbahar; Izgi, Belgin; Temel, Ahmet; Yildirim, Nilgun; Okka, Mehmet; Özcan, Altan; Yüksel, Nurşen; Elgin, Ufuk; Altan, Çiğdem; Ozer, Baris

2017-01-01

Objective The objective of this study was to assess the intraocular pressure (IOP)-lowering efficacy, tolerability, safety, and usage patterns of prostaglandin analog/prostamide (PGA/P)-containing topical ocular hypotensives in ocular hypertension (OHT) and primary open-angle glaucoma in the Turkish clinical setting. Methods This non-interventional, multicenter study enrolled previously treated patients who failed to achieve target IOP (or experienced unacceptable adverse events [AEs]) and were prescribed a PGA/P-containing IOP-lowering agent. Treatment was initiated at baseline (V1), and patients returned at weeks 4–6 (V2) and 8–12 (V3). The primary efficacy measure was the change in IOP from baseline at V3 in each eye. The secondary measures were physician’s assessment of IOP-lowering efficacy, patients (%) reaching target IOP determined at V1, hyperemia score, physician and patient assessment of study treatment tolerability at V3, and AE frequency/severity. A subgroup analysis of patients receiving the most common study treatment was conducted. All analyses were performed using the safety population (patients who received one or more doses and had any data available). Results Of 358 enrolled patients, 60.6% had primary open-angle glaucoma, 29.9% had secondary open-angle glaucoma (protocol amendment), and 13.1% had OHT; 13 patients had multiple diagnoses. At V3, the mean IOP change from baseline was ≥−4.2 mmHg (≥21.1%). IOP met or was lower than the target in 81.7% of patients, 95% exhibited none to mild conjunctival hyperemia (most common AE), and tolerability was rated good/very good by >91.1% of patients and physicians. The results were similar in patients who received the most common study treatment, bimatoprost 0.03%/timolol 0.5% (bim/tim; n=310). Conclusion PGA/P-containing medications, including bim/tim, significantly reduced IOP in previously treated patients with open-angle glaucoma or OHT; most reached their target IOP or an IOP even lower than their target and reported good/very good tolerability. PGA/P-containing medications such as bim/tim should be considered as a safe, effective therapeutic option for Turkish patients who exhibit poor response, tolerance, or adherence to their previous therapy. PMID:28458511

Doppler term in the galaxy two-point correlation function: Wide-angle, velocity, Doppler lensing and cosmic acceleration effects

NASA Astrophysics Data System (ADS)

Raccanelli, Alvise; Bertacca, Daniele; Jeong, Donghui; Neyrinck, Mark C.; Szalay, Alexander S.

2018-03-01

We study the parity-odd part (that we shall call Doppler term) of the linear galaxy two-point correlation function that arises from wide-angle, velocity, Doppler lensing and cosmic acceleration effects. As it is important at low redshift and at large angular separations, the Doppler term is usually neglected in the current generation of galaxy surveys. For future wide-angle galaxy surveys, however, we show that the Doppler term must be included. The effect of these terms is dominated by the magnification due to relativistic aberration effects and the slope of the galaxy redshift distribution and it generally mimics the effect of the local type primordial non-Gaussianity with the effective nonlinearity parameter fNLeff of a few; we show that this would affect forecasts on measurements of fNL at low-redshift. Our results show that a survey at low redshift with large number density over a wide area of the sky could detect the Doppler term with a signal-to-noise ratio of ∼ 1 - 20, depending on survey specifications.

A dynamic study of the anterior cruciate ligament of the knee using an open MRI.

PubMed

Guenoun, Daphne; Vaccaro, Julien; Le Corroller, Thomas; Barral, Pierre-Antoine; Lagier, Aude; Pauly, Vanessa; Coquart, Benjamin; Coste, Joel; Champsaur, Pierre

2017-03-01

Recent anatomical and radiological studies of the anterior cruciate ligament (ACL) suggest the ACL length and orientation change during knee flexion, and an open MRI sequencing during knee flexion enables a dynamic ACL analysis. This study's goal is to describe a normal ACL using a 1T open MRI and, in particular, variations in length and insertion angles at different degrees of flexion. Twenty-one volunteers with clinically healthy knees received a dynamic MRI with their knees in hyperextension, neutral position, and flexed at 45° and 90° angles. For each position, two radiologists measured the ACL lengths and angles of the proximal insertion between the ACL's anterior edge and the roof of the inter-condylar notch. Additionally, we measured the ACL's and the tibial plateau's distal angle insertion between their anterior edges and then compared these with the nonparametric Wilcoxon test. The ACL had a significant extension between the 90° flexion and all other positions (hyperextension: 31.75 ± 2.5 mm, neutral position: 32.5 ± 2.6 mm, 45°: 35.6 ± 1.6 mm, 90°: 35.6 ± 1.6 mm). There was also a significant increase of the angle insertion between the proximal 90° flexion and all other positions, as well as between hyperextension and bending to 45° (hyperextension: 2.45° ± 3.7°, neutral: 13.4° ± 9.7°, 45°: 33 25 ± 9.3, 90: 51.85° ± 9.3°). Additionally, there is a significant increase in the distal angle insertion for all positions (hyperextension: 133.2° ± 5.4°, neutral position: 134.95° ± 4.4°, 45°: 138.35° ± 5.9°, 90°: 149.15° ± 8.6°). Our study is the first to exhibit that a dynamic MRI has a significant ACL extension in vivo during bending. This concept opens the way for further studies to improve the diagnosis of traumatic ACL injuries using a dynamic MRI.

Single and double superimposing interferometer systems

DOEpatents

Erskine, David J.

2000-01-01

Interferometers which can imprint a coherent delay on a broadband uncollimated beam are described. The delay value can be independent of incident ray angle, allowing interferometry using uncollimated beams from common extended sources such as lamps and fiber bundles, and facilitating Fourier Transform spectroscopy of wide angle sources. Pairs of such interferometers matched in delay and dispersion can measure velocity and communicate using ordinary lamps, wide diameter optical fibers and arbitrary non-imaging paths, and not requiring a laser.

Visual imaging control systems of the Mariner to Jupiter and Saturn spacecraft

NASA Technical Reports Server (NTRS)

Larks, L.

1979-01-01

Design and fabrication of optical systems for the Mariner Jupiter Saturn (Voyager) mission is described. Because of the long distances of these planets from the sun, the spacecraft was designed without solar panels with the electricity generated on-board by radio-isotope thermal generators (RTG). The presence of RTG's and Jupiter radiation environment required that the optical systems be fabricated out of radiation stabilized materials. A narrow angle and a wide angle camera are located on the spacecraft scan platform, with the narrow angle lens a modification of the Mariner 10 lens. The optical system is described, noting that the lens was modified by moving the aperture correctors forward and placing a spider mounted secondary mirror in the original back surface of the second aperture corrector. The wide angle lens was made out of cerium doped, radiation stabilized optical glass with greatest blue transmittance, which would be resistant to RTG and Jupiter radiation.

Dielectric-based subwavelength metallic meanders for wide-angle band absorbers.

PubMed

Shen, Su; Qiao, Wen; Ye, Yan; Zhou, Yun; Chen, Linsen

2015-01-26

We propose nano-meanders that can achieve wide-angle band absorption in visible regime. The nano-meander consists of a subwavelength dielectric grating covered by continuous ultra-thin Aluminum film (less than one tenth of the incident wavelength). The excited photonic resonant modes, such as cavity mode, surface plasmonic mode and Rayleigh-Wood anomaly, are discussed in detail. Nearly total resonant absorption due to funneling mechanism in the air nano-groove is almost invariant with large incident angle in transverse magnetic polarization. From both the structural geometry and the nanofabrication point of view, the light absorber has a very simple geometrical structure and it is easy to be integrated into complex photonic devices. The highly efficient angle-robust light absorber can be potential candidate for a range of passive and active photonic applications, including solar-energy harvesting as well as producing artificial colors on a large scale substrate.

A method to measure internal contact angle in opaque systems by magnetic resonance imaging.

PubMed

Zhu, Weiqin; Tian, Ye; Gao, Xuefeng; Jiang, Lei

2013-07-23

Internal contact angle is an important parameter for internal wettability characterization. However, due to the limitation of optical imaging, methods available for contact angle measurement are only suitable for transparent or open systems. For most of the practical situations that require contact angle measurement in opaque or enclosed systems, the traditional methods are not effective. Based upon the requirement, a method suitable for contact angle measurement in nontransparent systems is developed by employing MRI technology. In the Article, the method is demonstrated by measuring internal contact angles in opaque cylindrical tubes. It proves that the method also shows great feasibility in transparent situations and opaque capillary systems. By using the method, contact angle in opaque systems could be measured successfully, which is significant in understanding the wetting behaviors in nontransparent systems and calculating interfacial parameters in enclosed systems.

[Sinus tarsi approach combined with medial distraction technique for treatment of intra-articular calcaneus fractures].

PubMed

Zhou, Haichao; Ren, Haoyang; Li, Bing; Yu, Tao; Yang, Yunfeng

2016-07-08

?To discuss the effectiveness of limited open reduction via sinus tarsi approach using medial distraction technique in the treatment of intra-articular calcaneus fractures by comparing with open reduction and internal fixation via extensile L-shaped incision. ?A retrospective analysis was made on the clinical data of 21 patients with intra-articular calcaneus fractures treated by sinus tarsi approach combined with medial distraction technique between April 2013 and November 2014 (minimally invasive group), and 32 patients treated by extensile L-shaped incision approach between June 2012 and September 2014 (extensile incision group). No significant difference was found in gender, age, injury pattern, fracture classification, time from injury to operation, preoperative Böhler angle, Gissane angle, calcaneal varus angle, the ankle and hind-foot score of American Orthopaedic Foot and Ankle Society (AOFAS), and visual analogue scale (VAS) score between 2 groups (P>0.05), which was comparable. The operation time, wound complications, and bone healing time were recorded. The postoperative function was also evaluated by AOFAS score and VAS score. The pre-and post-operative Böhler angle, Gissane angle, and calcaneal varus angle were measured on the X-ray films, and the corrective angle was calculated. ?Sixteen patients were followed up 6-18 months (mean, 11.5 months) in the minimally invasive group, and 23 patients for 6-24 months (mean, 13.5 months) in the extensile incision group. Difference was not significant in operation time between 2 groups (t=0.929, P=0.796). No complication occurred in the minimally invasive group; partial skin flap necrosis occurred in 3 cases of the extensile incision group, was cured after dressing change. There was no loosening of implants or reduction loss in 2 groups at last follow-up. Subtalar joint stiffness occurred in 1 case of the minimally invasive group and 4 cases of the extensile incision group, and 1 patient had discomfort for the implants in the extensile incision group. The bone healing time was (9.9±0.8) weeks in the minimally invasive group, and was (10.1±0.7) weeks in the extensile incision group, showing no significant difference (t=0.613, P=0.845 ). Böhler angle, Gissane angle, calcaneal varus angle, AOFAS score, and VAS score were significantly improved at last follow-up when compared with preoperative values in 2 groups (P<0.05), but there was no significant difference between 2 groups (P>0.05), and the corrective value of angle showed no significant difference between 2 groups (P>0.05). ?Limited open reduction via sinus tarsi approach for intra-articular calcaneus fractures could reduce the incidence of wound complications effectively. Meanwhile, the medial distraction technique is helpful to correct the heel varus deformity.

The crustal structure of the north-eastern Gulf of Aden continental margin: insights from wide-angle seismic data

NASA Astrophysics Data System (ADS)

Watremez, L.; Leroy, S.; Rouzo, S.; D'Acremont, E.; Unternehr, P.; Ebinger, C.; Lucazeau, F.; Al-Lazki, A.

2011-02-01

The wide-angle seismic (WAS) and gravity data of the Encens survey allow us to determine the deep crustal structure of the north-eastern Gulf of Aden non-volcanic passive margin. The Gulf of Aden is a young oceanic basin that began to open at least 17.6 Ma ago. Its current geometry shows first- and second-order segmentation: our study focusses on the Ashawq-Salalah second-order segment, between Alula-Fartak and Socotra-Hadbeen fracture zones. Modelling of the WAS and gravity data (three profiles across and three along the margin) gives insights into the first- and second-order structures. (1) Continental thinning is abrupt (15-20 km thinning across 50-100 km distance). It is accommodated by several tilted blocks. (2) The ocean-continent transition (OCT) is narrow (15 km wide). The velocity modelling provides indications on its geometry: oceanic-type upper-crust (4.5 km s-1) and continental-type lower crust (>6.5 km s-1). (3) The thickness of the oceanic crust decreases from West (10 km) to the East (5.5 km). This pattern is probably linked to a variation of magma supply along the nascent slow-spreading ridge axis. (4) A 5 km thick intermediate velocity body (7.6 to 7.8 km s-1) exists at the crust-mantle interface below the thinned margin, the OCT and the oceanic crust. We interpret it as an underplated mafic body, or partly intruded mafic material emplaced during a `post-rift' event, according to the presence of a young volcano evidenced by heat-flow measurement (Encens-Flux survey) and multichannel seismic reflection (Encens survey). We propose that the non-volcanic passive margin is affected by post-rift volcanism suggesting that post-rift melting anomalies may influence the late evolution of non-volcanic passive margins.

Differential protein expression in tears of patients with primary open angle and pseudoexfoliative glaucoma.

PubMed

Pieragostino, Damiana; Bucci, Sonia; Agnifili, Luca; Fasanella, Vincenzo; D'Aguanno, Simona; Mastropasqua, Alessandra; Ciancaglini, Marco; Mastropasqua, Leonardo; Di Ilio, Carmine; Sacchetta, Paolo; Urbani, Andrea; Del Boccio, Piero

2012-04-01

Primary open angle (POAG) and pseudoexfoliative glaucoma (PXG) are the most common primary and secondary forms of glaucoma, respectively. Even though the patho-physiology, aqueous humor composition, risk factors, clinical features, therapy and drug induced ocular surface changes in POAG and PXG have been widely studied, to date information concerning tear protein characterization is lacking. Tears are a source of nourishment for ocular surface tissues and a vehicle to remove local waste products, metabolized drugs and inflammatory mediators produced in several ophthalmic diseases. In glaucoma, the proteomic definition of tears may provide insights concerning patho-physiology of the disease and ocular surface modifications induced by topical therapy. Our study aimed at characterizing protein patterns in tears of patients with medically controlled POAG and PXG. A comparative tears proteomic analysis by label-free LC-MS(E) highlighted differences in the expression of several proteins in the two glaucoma sub-types and control subjects, highlighting inflammation pathways expressed in both diseases. Results were independently reconfirmed by SDS-PAGE and linear MALDI-TOF MS, validating altered levels of Lysozyme C, Lipocalin-1, Protein S100, Immunoglobulins and Prolactin Inducible Protein. Moreover, we found a differential pattern of phosphorylated Cystatin-S that distinguishes the two pathologies. The most relevant results suggest that in both pathologies there may be active inflammation pathways related to the disease and/or induced by therapy. We show, for the first time, tear protein patterns expressed under controlled intraocular pressure conditions in POAG and PXG subjects. These findings could help in the understanding of molecular machinery underlying these ophthalmologic diseases, resulting in early diagnosis and more specific therapy.

Perspectives for Distributed Observations of Near-Earth Space Using a Russian-Cuban Observatory

NASA Astrophysics Data System (ADS)

Bisikalo, D. V.; Savanov, I. S.; Naroenkov, S. A.; Nalivkin, M. A.; Shugarov, A. S.; Bakhtigaraev, N. S.; Levkina, P. A.; Ibragimov, M. A.; Kil'pio, E. Yu.; Sachkov, M. E.; Kartashova, A. P.; Fateeva, A. M.; Uratsuka, Marta R. Rodriguez; Estrada, Ramses Zaldivar; Diaz, Antonio Alonsa; Rodríguez, Omar Pons; Figuera, Fidel Hernandes; Garcia, Maritza Garcia

2018-06-01

The creation of a specialized network of large, wide-angle telescopes for distributed observations of near-Earth space using a Russian-Cuban Observatory is considered. An extremely important goal of routine monitoring of near-Earth and near-Sun space is warding off threats with both natural and technogenic origins. Natural threats are associated with asteroids or comets, and technogenic threats with man-made debris in near-Earth space. A modern network of ground-based optical instruments designed to ward off such threats must: (a) have a global and, if possible, uniform geographic distribution, (b) be suitable for wide-angle, high-accuracy precision survey observations, and (c) be created and operated within a single network-oriented framework. Experience at the Institute of Astronomy on the development of one-meter-class wide-angle telescopes and elements of a super-wide-angle telescope cluster is applied to determine preferences for the composition of each node of such a network. The efficiency of distributed observations in attaining maximally accurate predictions of the motions of potentially dangerous celestial bodies as they approach the Earth and in observations of space debris and man-made satellites is estimated. The first estimates of astroclimatic conditions at the proposed site of the future Russian-Cuban Observatory in the mountains of the Sierra del Rosario Biosphere Reserve are obtained. Special attention is given to the possible use of the network to carry out a wide range of astrophysical studies, including optical support for the localization of gravitational waves and other transient events.

Mapping the megathrust beneath the northern Gulf of Alaska using wide-angle seismic reflection/refraction profiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brocher, T.M.; Fuis, G.S.; Fisher, M.A.

1993-04-01

In the northern Gulf of Alaska and Prince William Sound, wide-angle seismic reflection/refraction profiling, earthquake studies, and laboratory measurements of physical properties are used to determine the geometry of the Prince William and Yakutat terranes, and the subducting Pacific plate. In this complex region, the Yakutat terrane is underthrust beneath the Prince William terrane, and both terranes are interpreted to be underlain by the Pacific plate. Wide-angle seismic reflection/refraction profiles recorded along 5 seismic lines are used to unravel this terrane geometry. Modeled velocities in the upper crust of the Prince William terrane (to 18-km depth) agree closely with laboratorymore » velocity measurements of Orca Group phyllites and quartzofeldspathic graywackes (the chief components of the Prince William terrane) to hydrostatic pressures as high as 600 MPa (6 KBAR). An interpretation consistent with these data extends the Prince William terrane to at least 18-km depth. A landward dipping reflection at depths of 16--24 km is interpreted as the base of the Prince William terrane. This reflector corresponds to the top of the Wadati-Benioff zone seismicity and is interpreted as the megathrust. Beneath this reflector is a 6.9-km/s refractor, that is strongly reflective and magnetic, and is interpreted to be gabbro in Eocene age oceanic crust of the underthrust Yakutat terrane. Both wide-angle seismic and magnetic anomaly data indicate that the Yakutat terrane has been underthrust beneath the Prince William terrane for at least a few hundred kilometers. Wide-angle seismic data are consistent with a 9 to 10[degree] landward dip of the subducting Pacific plate, distinctly different from the inferred average 3 to 4[degree] dip of the overlying 6.9-km/s refractor and Wadati-Benioff seismic zone. The preferred interpretation of the geophysical data is that one composite plate, composed of the Pacific and Yakutat plates, is subducting beneath southern Alaska.« less

The Tethys Rifting of the Valencia Trough Basin

NASA Astrophysics Data System (ADS)

Viñas, Marina; Ranero, César R.; Cameselle, Alejandra L.

2017-04-01

The western Mediterranean submarine realm is composed of several basin inferred to be formed by a common geodynamic process: upper plate extension during slab rollback of a retreating subduction zone. Although the time evolution of the geometry of the trenches is debated, all models assume that basins opened sequentially from NW (Gulf of Lions) towards the SE (Ligurian-Provençal and later Tyrrhenian basins) and SW (Valencia Trough and later Algerian-South Balearic and Alboran Basin) as trenches migrated. Basin opening history is key to reconstruct kinematics of slab retreat preferred in each model. However, the deep structure of basins is inadequately known due to the paucity of modern wide-angle and multichannel reflection seismic studies across entire systems, and absence of deep drilling in the deep-water regions of the basins, as a result, much of the opening evolution is inferred from indirect evidence. In the Valencia Trough Basin (VTB), drilling and vintage seismic data provide good knowledge of the shallow geology of the basin. However, crustal-scale information across the entire VTB has been limited to two studies (Figure 1): One in the late 80's (Valsis experiment) with three Expanded Spread Profiles that yielded local 1D velocity/depth models used to constrain 2D gravity modeling, and a few multichannel seismic profiles along the Iberian shelf and across segments of the basin. A second study in the early 90's (ESCI experiment) collected a low-resolution deep-penetration multichannel seismic reflection profile across the basin and a coincident wide-angle seismic line with numerous land stations in Iberia but a handful of widely-spaced Ocean Bottom Seismometers. In the absence of modern detailed crustal structure, the origin and evolution of the VTB is still debated. Industry multichannel seismic reflection profiles cover the SW segment of the VTB. This is a region where the basin sea floor is comparatively shallower and has numerous industry wells reaching deep into the sediment sequence, which provides an unprecedented view of the tectonic structure and distribution of synrift deposits across the entire basin, from the Iberian to the North Balearic margin (Figure 2). Here we first show that the seismic records provide full crustal-scale information. Later we discuss the tectonic and sedimentary structure that supports that crustal stretching and basin formation of the VTB occurred fundamentally during the Mesozoic times by strike-slip tectonics and not during Tertiary times by back-arc extension. We show that the current sea floor morphological configuration giving rise to the so-called Valencia Trough does not represent the changes in crystalline basement thickness related to rifting, but fundamentally a product of sediment dynamics, particularly by the development during post-Messinian times of the Ebro-river delta. Our results are significant to understand Tethyan rifting and need to be considered for plate kinematic reconstructions of the western Mediterranean.

Neurovascular structures of the mandibular angle and condyle: a comprehensive anatomical review.

PubMed

Yang, Hun-Mu; Won, Sung-Yoon; Kim, Hee-Jin; Hu, Kyung-Seok

2015-11-01

Various surgical interventions including esthetic surgery, salivary gland excision, and open reduction of fracture have been performed in the area around the mandibular angle and condyle. This study aimed to comprehensively review the anatomy of the neurovascular structures on the angle and condyle with recent anatomic and clinical research. We provide detailed information about the branching and distributing patterns of the neurovascular structures at the mandibular angle and condyle, with reported data of measurements and proportions from previous anatomical and clinical research. Our report should serve to help practitioners gain a better understanding of the area in order or reduce potential complications during local procedures. Reckless manipulation during mandibular angle reduction could mutilate arterial branches, not only from the facial artery, but also from the external carotid artery. The transverse facial artery and superficial temporal artery could be damaged during approach and incision in the condylar area. The marginal mandibular branch of the facial nerve can be easily damaged during submandibular gland excision or facial rejuvenation treatment. The main trunk of the facial nerve and its upper and lower distinct divisions have been damaged during parotidectomy, rhytidectomy, and open reductions of condylar fractures. By revisiting the information in the present study, surgeons will be able to more accurately prevent procedure-related complications, such as iatrogenic vascular accidents on the mandibular angle and condyle, complete and partial facial palsy, gustatory sweating (Frey syndrome), and traumatic neuroma after parotidectomy.

Trabecular Meshwork Height in Primary Open-Angle Glaucoma Versus Primary Angle-Closure Glaucoma.

PubMed

Masis, Marisse; Chen, Rebecca; Porco, Travis; Lin, Shan C

2017-11-01

To determine if trabecular meshwork (TM) height differs between primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) eyes. Prospective, cross-sectional clinical study. Adult patients were consecutively recruited from glaucoma clinics at the University of California, San Francisco, from January 2012 to July 2015. Images were obtained from spectral-domain optical coherence tomography (Cirrus OCT; Carl Zeiss Meditec, Inc, Dublin, California, USA). Univariate and multivariate linear mixed models comparing TM height and glaucoma type were performed to assess the relationship between TM height and glaucoma subtype. Mixed-effects regression was used to adjust for the use of both eyes in some subjects. The study included 260 eyes from 161 subjects, composed of 61 men and 100 women. Mean age was 70 years (SD 11.77). There were 199 eyes (123 patients) in the POAG group and 61 eyes (38 patients) in the PACG group. Mean TM heights in the POAG and PACG groups were 812 ± 13 μm and 732 ± 27 μm, respectively, and the difference was significant in univariate analysis (P = .004) and in multivariate analysis (β = -88.7 [24.05-153.5]; P = .008). In this clinic-based population, trabecular meshwork height is shorter in PACG patients compared to POAG patients. This finding may provide insight into the pathophysiology of angle closure and provide assistance in future diagnosis, prevention, and management of the angle-closure spectrum of disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

16 CFR 1500.43 - Method of test for flashpoint of volatile flammable materials by Tagliabue open-cup apparatus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... inches in length, with a right-angle bend 1/2-inch from each end. This wire is placed snugly in holes... form a top when shield is open). The interior of the draft shield shall be painted a flat black...

16 CFR 1500.43 - Method of test for flashpoint of volatile flammable materials by Tagliabue open-cup apparatus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... inches in length, with a right-angle bend 1/2-inch from each end. This wire is placed snugly in holes... form a top when shield is open). The interior of the draft shield shall be painted a flat black...

Prevalence of comorbid retinal disease in patients with glaucoma at an academic medical center.

PubMed

Griffith, Joseph F; Goldberg, Jeffrey L

2015-01-01

Patients with various retinal diseases and patients who have undergone retinal procedures and surgeries have an increased risk of developing ocular hypertension and glaucoma. Little is known about the epidemiology of comorbid retinal diseases in glaucoma patients. This study evaluated the prevalence of retinal comorbidities in a population of patients with five types of glaucoma. A longitudinal, retrospective study was conducted using International Classification of Disease (ICD-9) billing records from 2003 to 2010 at an academic medical center. Patients were classified as having primary open-angle glaucoma (POAG), low tension open-angle glaucoma (NTG), pigmentary open-angle glaucoma, chronic-angle closure glaucoma (CACG), or pseudoexfoliation glaucoma (PXG) if they had at least three clinic visits with the same ICD-9 code. Patients were classified as having a retinal comorbidity if they had two visits with the same code. Variables were analyzed with the independent t-test, χ (2) test, analysis of variance, or Fisher's exact test. A total of 5,154 patients had glaucoma, and 14.8% of these had a retinal comorbidity. The prevalence of comorbid retinal disease was higher in patients with POAG (15.7%) than in those with NTG (10.7%), PXG (10.1%), or pigmentary open-angle glaucoma (3.7%; P<0.05). Two hundred and two patients had diabetic retinopathy, with POAG patients (4.5%) having a higher prevalence than those with CACG (1.4%) or PXG (0.6%; P<0.001). There were 297 patients who had macular degeneration and both POAG (2.0%) and PXG patients (2.9%) had a higher prevalence of nonexudative macular degeneration than those with CACG (0%; P<0.01). Patients with comorbid retinal disease had a higher prevalence of blindness and low vision than those without comorbid retinal disease (1.97% versus 1.02%, P=0.02). The high prevalence of comorbid retinal disease and the nearly twofold increase in blindness and low vision in this population demonstrate the need for ophthalmologists to determine if patients have multiple etiologies for their vision loss. The higher prevalence of certain retinal diseases in POAG patients may reflect common pathophysiological processes that warrant further investigation.

SU-G-TeP4-03: A Multileaf Collimator Calibration and Quality Assurance Technique Using An Electronic Portal Imaging Device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lebron, S; Yan, G; Li, J

2016-06-15

Purpose: To develop an accurate and quick multileaf collimator (MLC) calibration and quality assurance technique using an electronic portal imaging device (EPID) Methods: The MLC models used include the MLCi and Agility (Elekta Ltd). This technique consists of two 22(L)x10(W) cm{sup 2} fields with 0{sup 0} and 180{sup 0} collimator angles centered to an offset EPID. The MLC opening is estimated by calculating the profile at the image’s center in the image’s horizontal direction. Scans in the image’s vertical direction were calculated every 20 pixels in the inner 70% of estimated MLC opening. The profiles’ edges were fitted with linearmore » equations to determine the image’s rotation angle. Then, crossline profiles were scanned at the center of each leaf taking into account the leaf’s width at isocenter and the rotation angle. The profiles’ edges determine the location of the leaves’ edges and these were subtracted from the reference leaf’s position in order to determine the relative leaf offsets. The edge location of all profiles was determined by using the parameterized gradient of the penumbra region. The technique was tested against an established diode array-based method, and for different MLC systems, patterns, gantry angles, days, energies, beam modalities and MLC openings. Results: The differences between the proposed and established methods were 0.26±0.19mm. The leaf offsets’ deviation was <0.3mm (5 months period). For pattern fields, the differences between predetermined and calculated offsets were 0.18±0.18mm. The leaf offset deviation of measurements with different energies and MLC openings were <0.1mm and <0.3mm, respectively. The differences between offsets of FF and FFF beams were 0.01±0.02mm (<0.07mm). The differences between the offsets at different gantry angles were 0.08±0.15mm. Conclusion: The proposed method proved to be accurate and efficient in calculating the relative leaf offsets. Parameterized field edge is essential to obtain accurate result by eliminating the noise from EPID.« less

Effects of anode geometry on forward wide-angle neon ion emissions in 3.5 kJ plasma focus device by novel mega-size panorama polycarbonate image detectors

NASA Astrophysics Data System (ADS)

Sohrabi, M.; Soltani, Z.; Sarlak, Z.

2018-03-01

Forward wide-angle neon ion emissions in a 3.5 kJ plasma focus device (PFD) were studied using 5 different anode top geometries; hollow-end cylinder, solid triangle, solid hemisphere, hollow-end cone and flat-end cone. Position-sensitive mega-size panorama polycarbonate ion image detectors (MS-PCID) developed by dual-cell circular mega-size electrochemical etching (MS-ECE) systems were applied for processesing wide-angle neon ion images on MS-PCIDs exposed on the PFD cylinder top base under a single pinch shot. The images can be simply observed, analyzed and relatively quantified in terms of ion emission angular distributions even by the unaided eyes. By analysis of the forward neon ion emission images, the ion emission yields, ion emission angular distributions, iso-fluence ion contours and solid angles of ion emissions in 4π PFD space were determined. The neon ion emission yields on the PFD cylinder top base are in an increasing order ~2.1×109, ~2.2 ×109, ~2.8×109, ~2.9×109, and ~3.5×109 neon ions/shot for the 5 stated anode top geometries respectively. The panorama neon ion images as diagnosed even by the unaided eyes demonstrate the lowest and highest ion yields from the hollow-end cylinder and flat-end cone anode tops respectively. Relative dynamic qualitative neon ion spectrometry was made by the unaided eyes demonstrating relative neon ion energy as they appear. The study also demonstrates the unique power of the MS-PCID/MS-ECE imaging system as an advanced state-of-the-art ion imaging method for wide-angle dynamic parametric studies in PFD space and other ion study applications.

Precision determination of electron scattering angle by differential nuclear recoil energy method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liyanage, N.; Saenboonruang, K.

2015-12-01

The accurate determination of the scattered electron angle is crucial to electron scattering experiments, both with open-geometry large-acceptance spectrometers and ones with dipole-type magnetic spectrometers for electron detection. In particular, for small central-angle experiments using dipole-type magnetic spectrometers, in which surveys are used to measure the spectrometer angle with respect to the primary electron beam, the importance of the scattering angle determination is emphasized. However, given the complexities of large experiments and spectrometers, the accuracy of such surveys is limited and insufficient to meet demands of some experiments. In this article, we present a new technique for determination of themore » electron scattering angle based on an accurate measurement of the primary beam energy and the principle of differential nuclear recoil. This technique was used to determine the scattering angle for several experiments carried out at the Experimental Hall A, Jefferson Lab. Results have shown that the new technique greatly improved the accuracy of the angle determination compared to surveys.« less

Precision Determination of Electron Scattering Angle by Differential Nuclear Recoil Energy Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liyanage, Nilanga; Saenboonruang, Kiadtisak

2015-09-01

The accurate determination of the scattered electron angle is crucial to electron scattering experiments, both with open-geometry large-acceptance spectrometers and ones with dipole-type magnetic spectrometers for electron detection. In particular, for small central-angle experiments using dipole-type magnetic spectrometers, in which surveys are used to measure the spectrometer angle with respect to the primary electron beam, the importance of the scattering angle determination is emphasized. However, given the complexities of large experiments and spectrometers, the accuracy of such surveys is limited and insufficient to meet demands of some experiments. In this article, we present a new technique for determination of themore » electron scattering angle based on an accurate measurement of the primary beam energy and the principle of differential nuclear recoil. This technique was used to determine the scattering angle for several experiments carried out at the Experimental Hall A, Jefferson Lab. Results have shown that the new technique greatly improved the accuracy of the angle determination compared to surveys.« less

An efficient multiplexing approach for adaptive aircraft communications via a relay satellite.

NASA Technical Reports Server (NTRS)

Devieux, C.; Bisaga, J. J.

1973-01-01

Description of a coherent wide-angle multiplexing approach which is 4 to 8 dB more efficient in the utilization of satellite power as compared to a multicarrier transmission accessing a single TWT amplifier transponder. The wide-angle multiplexing approach achieves this performance by efficiently trading the modulation power improvement against backoff at the satellite earth terminal phase modulator. A simple addition of an amplitude clipper at the modulator input is critical to the proper operation of the system.

Portable mini-chamber for temperature dependent studies using small angle and wide angle x-ray scattering

NASA Astrophysics Data System (ADS)

Dev, Arun Singh; Kumar, Dileep; Potdar, Satish; Pandit, Pallavi; Roth, Stephan V.; Gupta, Ajay

2018-04-01

The present work describes the design and performance of a vacuum compatible portable mini chamber for temperature dependent GISAXS and GIWAXS studies of thin films and multilayer structures. The water cooled body of the chamber allows sample annealing up to 900 K using ultra high vacuum compatible (UHV) pyrolytic boron nitride heater, thus making it possible to study the temperature dependent evolution of structure and morphology of two-dimensional nanostructured materials. Due to its light weight and small size, the chamber is portable and can be accommodated at synchrotron facilities worldwide. A systematic illustration of the versatility of the chamber has been demonstrated at beamline P03, PETRA-III, DESY, Hamburg, Germany. Temperature dependent grazing incidence small angle x-ray scattering (GISAXS) and grazing incidence wide angle x-ray scattering (GIWAXS) measurements were performed on oblique angle deposited Co/Ag multilayer structure, which jointly revealed that the surface diffusion in Co columns in Co/Ag multilayer enhances by increasing temperature from RT to ˜573 K. This results in a morphology change from columnar tilted structure to densely packed morphological isotropic multilayer.

Characteristics of a wind-actuated aerodynamic braking device for high-speed trains

NASA Astrophysics Data System (ADS)

Takami, H.; Maekawa, H.

2017-04-01

To shorten the stopping distance of the high speed trains in case of emergency, we developed a small-sized aerodynamic braking unit without use of the friction between a rail and a wheel. The developed device could actuate a pair of two drag panels with a travelling wind. However, after the drag panel fully opened, vibrational movements of the drag panel characterized by its slight flutter were repeated. In this study, to stabilize the opened panel, matters pertaining to the angle of attack with respect to the drag panel and pertaining to the arrangement of the two panels were examined by a wind tunnel experiment using a scale model. As a result, to stabilize the opened panel and to keep the good performance of the braking device, it is found out that an angle of attack of 75 to 80 degrees is suitable provided that the interval of the two panels is narrow enough.

A predictive factor for acquiring an ideal lower limb realignment after opening-wedge high tibial osteotomy.

PubMed

Bito, Haruhiko; Takeuchi, Ryohei; Kumagai, Ken; Aratake, Masato; Saito, Izumi; Hayashi, Riku; Sasaki, Yohei; Aota, Yoichi; Saito, Tomoyuki

2009-04-01

Obtaining a correct postoperative limb alignment is an important factor in achieving a successful clinical outcome after an opening-wedge high tibial osteotomy (OWHTO). To better predict some of the aspects that impact upon the clinical outcomes following this procedure, including postoperative correction loss and over correction, we examined the changes in the frontal plane of the lower limb in a cohort of patients who had undergone OWHTO using radiography. Forty-two knees from 33 patients (23 cases of osteoarthritis and 10 of osteonecrosis) underwent a valgus realignment OWHTO procedure and were radiographically assessed for changes that occurred pre- and post-surgery. The mean femorotibial angle (FTA) was found to be 182.1 +/- 2.0 degrees (12 +/- 2.0 anatomical varus angulation) preoperatively and 169.6 +/- 2.4 degrees (10.4 +/- 2.4 anatomical valgus angulation) postoperatively. These measurements thus revealed significant changes in the weight bearing line ratio (WBL), femoral axis angle (FA), tibial axis angle (TA), tibia plateau angle (TP), tibia vara angle (TV) and talar tilt angle (TT) following OWHTO. In contrast, no significant change was found in the weight bearing line angle (WBLA) after these treatments. To assess the relationship between the correction angle and these indexes, 42 knees were divided into the following three groups according to the postoperative FTA; a normal correction group (168 degrees < or = FTA < or = 172 degrees ), an over-correction group (FTA < 168 degrees ), and an under-correction group (FTA > 172 degrees ). There were significant differences in the delta angle [DA; calculated as (pre FTA - post FTA) - (pre TV - post TV)] among each group of patients. Our results thus indicate a negative correlation between the DA and preoperative TA (R(2) = 0.148, p < 0.05). Hence, given that the correction errors in our patients appear to negatively correlate with the preoperative TA, postoperative malalignments are likely to be predictable prior to surgery.

Wide Angle, Single Screen, Gridded Square-Loop Frequency Selective Surface for Diplexing Two Closely Separated Frequency Bands

NASA Technical Reports Server (NTRS)

Wu, Te-Kao (Inventor)

1996-01-01

The design and performance of a wide angle, single screen, frequency selective surface (FSS) with gridded square-loop path elements are described for diplexing closely separated signal bands, for example, X- and Ku-band signals in an Orbiting Very Long Baseline Interferometer (OVLBI) earth station reflector antenna system, as well as other applications such as military and commercial communications via satellites. Excellent agreement is obtained between the predicted and measured results of this FSS design using the gridded square-loop patch elements sandwiched between 0.0889 cm thick tetrafluoroethylene fluorocarbon polymer (PTFE) slabs. Resonant frequency drift is reduced by 1 GHz with an incidence angle from 0 deg normal to 40 deg from normal.

Reflection color filters of the three primary colors with wide viewing angles using common-thickness silicon subwavelength gratings.

PubMed

Kanamori, Yoshiaki; Ozaki, Toshikazu; Hane, Kazuhiro

2014-10-20

We fabricated reflection color filters of the three primary colors with wide viewing angles using silicon two-dimensional subwavelength gratings on the same quartz substrate. The grating periods were 400, 340, and 300 nm for red, green, and blue filters, respectively. All of the color filters had the same grating thickness of 100 nm, which enabled simple fabrication of a color filter array. Reflected colors from the red, green, and blue filters under s-polarized white-light irradiation appeared in the respective colors at incident angles from 0 to 50°. By rigorous coupled-wave analysis, the dimensions of each color filter were designed, and the calculated reflectivity was compared with the measured reflectivity.

What is MISR? MISR Instrument? MISR Project?

Atmospheric Science Data Center

2014-12-08

... to improve our understanding of the Earth's environment and climate. Viewing the sunlit Earth simultaneously at nine widely-spaced angles, ... types of atmospheric particles and clouds on climate. The change in reflection at different view angles affords the means to distinguish ...

An Exploratory Investigation of the Role of Openness in Relationship Quality among Emerging Adult Chinese Couples

PubMed Central

Zhou, Yixin; Wang, Kexin; Chen, Shuang; Zhang, Jianxin; Zhou, Mingjie

2017-01-01

This study tested emerging adult couples’ openness and its fit effect on their romantic relationship quality using quadratic polynomial regression and response surface analysis. Participants were 260 emerging adult dyads. Both dyads’ openness and relationship quality were measured. The result showed that (1) female and male openness contribute differently to relationship quality; (2) couples with similar high openness could experience better relationship quality than those with similar low openness traits; and (3) when dyadic openness is dissimilar, it is better to be either relatively high or relatively low than to be moderate. These findings highlight the role of openness in emerging adults’ romantic relationships from a dyadic angle. PMID:28360875

Mitral Valve Stenosis after Open Repair Surgery for Non-rheumatic Mitral Valve Regurgitation: A Review.

PubMed

Shabsigh, Muhammad; Lawrence, Cassidy; Rosero-Britton, Byron R; Kumar, Nicolas; Kimura, Satoshi; Durda, Michael Andrew; Essandoh, Michael

2016-01-01

Mitral stenosis (MS) after mitral valve (MV) repair is a slowly progressive condition, usually detected many years after the index MV surgery. It is defined as a mean transmitral pressure gradient (TMPG) >5 mmHg or a mitral valve area (MVA) <1.5 cm(2). Pannus formation around the mitral annulus or extending to the mitral leaflets is suggested as the main mechanism for developing delayed MS after MV repair. On the other hand, early stenosis is thought to be a direct result of an undersized annuloplasty ring. Furthermore, in MS following ischemic mitral regurgitation (MR) repair, subvalvular tethering is the hypothesized pathophysiology. MS after MV repair has an incidence of 9-54%. Several factors have been associated with a higher risk for developing MS after MV repair, including the use of flexible Duran annuloplasty rings versus rigid Carpentier-Edwards rings, complete annuloplasty rings versus partial bands, small versus large anterior leaflet opening angle, and anterior leaflet tip opening length. Intraoperative echocardiography can measure the anterior leaflet opening angle, the anterior leaflet tip opening dimension, the MVA and the mean TMPG, and may help identify patients at risk for developing MS after MV repair.

Mitral Valve Stenosis after Open Repair Surgery for Non-rheumatic Mitral Valve Regurgitation: A Review

PubMed Central

Shabsigh, Muhammad; Lawrence, Cassidy; Rosero-Britton, Byron R.; Kumar, Nicolas; Kimura, Satoshi; Durda, Michael Andrew; Essandoh, Michael

2016-01-01

Mitral stenosis (MS) after mitral valve (MV) repair is a slowly progressive condition, usually detected many years after the index MV surgery. It is defined as a mean transmitral pressure gradient (TMPG) >5 mmHg or a mitral valve area (MVA) <1.5 cm2. Pannus formation around the mitral annulus or extending to the mitral leaflets is suggested as the main mechanism for developing delayed MS after MV repair. On the other hand, early stenosis is thought to be a direct result of an undersized annuloplasty ring. Furthermore, in MS following ischemic mitral regurgitation (MR) repair, subvalvular tethering is the hypothesized pathophysiology. MS after MV repair has an incidence of 9–54%. Several factors have been associated with a higher risk for developing MS after MV repair, including the use of flexible Duran annuloplasty rings versus rigid Carpentier–Edwards rings, complete annuloplasty rings versus partial bands, small versus large anterior leaflet opening angle, and anterior leaflet tip opening length. Intraoperative echocardiography can measure the anterior leaflet opening angle, the anterior leaflet tip opening dimension, the MVA and the mean TMPG, and may help identify patients at risk for developing MS after MV repair. PMID:27148540

A platform for dynamic simulation and control of movement based on OpenSim and MATLAB.

PubMed

Mansouri, Misagh; Reinbolt, Jeffrey A

2012-05-11

Numerical simulations play an important role in solving complex engineering problems and have the potential to revolutionize medical decision making and treatment strategies. In this paper, we combine the rapid model-based design, control systems and powerful numerical method strengths of MATLAB/Simulink with the simulation and human movement dynamics strengths of OpenSim by developing a new interface between the two software tools. OpenSim is integrated with Simulink using the MATLAB S-function mechanism, and the interface is demonstrated using both open-loop and closed-loop control systems. While the open-loop system uses MATLAB/Simulink to separately reproduce the OpenSim Forward Dynamics Tool, the closed-loop system adds the unique feature of feedback control to OpenSim, which is necessary for most human movement simulations. An arm model example was successfully used in both open-loop and closed-loop cases. For the open-loop case, the simulation reproduced results from the OpenSim Forward Dynamics Tool with root mean square (RMS) differences of 0.03° for the shoulder elevation angle and 0.06° for the elbow flexion angle. MATLAB's variable step-size integrator reduced the time required to generate the forward dynamic simulation from 7.1s (OpenSim) to 2.9s (MATLAB). For the closed-loop case, a proportional-integral-derivative controller was used to successfully balance a pole on model's hand despite random force disturbances on the pole. The new interface presented here not only integrates the OpenSim and MATLAB/Simulink software tools, but also will allow neuroscientists, physiologists, biomechanists, and physical therapists to adapt and generate new solutions as treatments for musculoskeletal conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

A platform for dynamic simulation and control of movement based on OpenSim and MATLAB

PubMed Central

Mansouri, Misagh; Reinbolt, Jeffrey A.

2013-01-01

Numerical simulations play an important role in solving complex engineering problems and have the potential to revolutionize medical decision making and treatment strategies. In this paper, we combine the rapid model-based design, control systems and powerful numerical method strengths of MATLAB/Simulink with the simulation and human movement dynamics strengths of OpenSim by developing a new interface between the two software tools. OpenSim is integrated with Simulink using the MATLAB S-function mechanism, and the interface is demonstrated using both open-loop and closed-loop control systems. While the open-loop system uses MATLAB/Simulink to separately reproduce the OpenSim Forward Dynamics Tool, the closed-loop system adds the unique feature of feedback control to OpenSim, which is necessary for most human movement simulations. An arm model example was successfully used in both open-loop and closed-loop cases. For the open-loop case, the simulation reproduced results from the OpenSim Forward Dynamics Tool with root mean square (RMS) differences of 0.03° for the shoulder elevation angle and 0.06° for the elbow flexion angle. MATLAB’s variable step-size integrator reduced the time required to generate the forward dynamic simulation from 7.1 s (OpenSim) to 2.9 s (MATLAB). For the closed-loop case, a proportional–integral–derivative controller was used to successfully balance a pole on model’s hand despite random force disturbances on the pole. The new interface presented here not only integrates the OpenSim and MATLAB/Simulink software tools, but also will allow neuroscientists, physiologists, biomechanists, and physical therapists to adapt and generate new solutions as treatments for musculoskeletal conditions. PMID:22464351

[The short nose].

PubMed

Levet, Y

2014-12-01

Short noses are not only depending on the length of the dorsum, but also if there is a saddle deformity, or a too lower situation of the fronto-nasal angle, or an open naso-labial angle or a rim retraction. All the cases are treated, often with the help of cartilage grafts and with a closed approach. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

3. Elevation view of entire midsection using ultrawide angle lens. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. Elevation view of entire midsection using ultrawide angle lens. Note opened south doors and closed north doors. The following photo WA-203-C-4 is similar except the camera position was moved right to include the slope of the south end. - Puget Sound Naval Shipyard, Munitions Storage Bunker, Naval Ammunitions Depot, South of Campbell Trail, Bremerton, Kitsap County, WA

Colliding Stellar Winds Structure and X-ray Emission

NASA Astrophysics Data System (ADS)

Pittard, J. M.; Dawson, B.

2018-04-01

We investigate the structure and X-ray emission from the colliding stellar winds in massive star binaries. We find that the opening angle of the contact discontinuity (CD) is overestimated by several formulae in the literature at very small values of the wind momentum ratio, η. We find also that the shocks in the primary (dominant) and secondary winds flare by ≈20° compared to the CD, and that the entire secondary wind is shocked when η ≲ 0.02. Analytical expressions for the opening angles of the shocks, and the fraction of each wind that is shocked, are provided. We find that the X-ray luminosity Lx∝η, and that the spectrum softens slightly as η decreases.

Efficiency of geometric designs of flexible solar panels: mathematical simulation

NASA Astrophysics Data System (ADS)

Marciniak, Malgorzata; Hassebo, Yasser; Enriquez-Torres, Delfino; Serey-Roman, Maria Ignacia

2017-09-01

The purpose of this study is to analyze various surfaces of flexible solar panels and compare them to the traditional at panels mathematically. We evaluated the efficiency based on the integral formulas that involve flux. We performed calculations for flat panels with different positions, a cylindrical panel, conical panels with various opening angles and segments of a spherical panel. Our results indicate that the best efficiency per unit area belongs to particular segments of spherically-shaped panels. In addition, we calculated the optimal opening angle of a cone-shaped panel that maximizes the annual accumulation of the sun radiation per unit area. The considered shapes are presented below with a suggestion for connections of the cells.

Growth optimization toward low angle incidence microchannel epitaxy of GaN using ammonia-based metal-organic molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Lin, Chia-Hung; Abe, Ryota; Uchiyama, Shota; Maruyama, Takahiro; Naritsuka, Shigeya

2012-08-01

Growth optimization toward low angle incidence microchannel epitaxy (LAIMCE) of GaN was accomplished using ammonia-based metal-organic molecular beam epitaxy (NH3-based MOMBE). Firstly, the [NH3]/[trimethylgallium (TMG)] ratio (R) dependence of selective GaN growth was studied. The growth temperature was set at 860 °C while R was varied from 5 to 200 with precursors being supplied parallel to the openings cut in the SiO2 mask. The selectivity of the growth was superior for all R, because TMG and NH3 preferably decompose on the GaN film. The formation of {112¯0}GaN or {112¯2}GaN sidewalls and (0001)GaN surface were observed by the change in R. The intersurface diffusion of Ga adatoms was also changed by a change in R. Ga adatoms migrate from the sidewalls to the top at R lower than 50, whereas the migration weakened with R greater than 100. Secondly, LAIMCE was optimized by changing the growth temperature. Consequently, 6 μm wide lateral overgrowth in the direction of precursor incidence was achieved with no pit after etching by H3PO4, which was six times wider than that in the opposite direction.

Determination of the structural phase and octahedral rotation angle in halide perovskites

DOE PAGES

dos Reis, Roberto; Yang, Hao; Ophus, Colin; ...

2018-02-12

A key to the unique combination of electronic and optical properties in halide perovskite materials lies in their rich structural complexity. However, their radiation sensitive nature limits nanoscale structural characterization requiring dose efficient microscopic techniques in order to determine their structures precisely. In this work, we determine the space-group and directly image the Br halide sites of CsPbBr 3, a promising material for optoelectronic applications. Based on the symmetry of high-order Laue zone reflections of convergent-beam electron diffraction, we identify the tetragonal (I4/mcm) structural phase of CsPbBr 3 at cryogenic temperature. Electron ptychography provides a highly sensitive phase contrast measurementmore » of the halide positions under low electron-dose conditions, enabling imaging of the elongated Br sites originating from the out-of-phase octahedral rotation viewed along the [001] direction of I4/mcm persisting at room temperature. The measurement of these features and comparison with simulations yield an octahedral rotation angle of 6.5°(±1.5°). Finally, the approach demonstrated here opens up opportunities for understanding the atomic scale structural phenomena applying advanced characterization tools on a wide range of radiation sensitive halide-based all-inorganic and hybrid organic-inorganic perovskites.« less

Champagne flutes and brandy snifters: modelling protostellar outflow-cloud chemical interfaces

NASA Astrophysics Data System (ADS)

Rollins, R. P.; Rawlings, J. M. C.; Williams, D. A.; Redman, M. P.

2014-10-01

A rich variety of molecular species has now been observed towards hot cores in star-forming regions and in the interstellar medium. An increasing body of evidence from millimetre interferometers suggests that many of these form at the interfaces between protostellar outflows and their natal molecular clouds. However, current models have remained unable to explain the origin of the observational bias towards wide-angled `brandy snifter' shaped outflows over narrower `champagne flute' shapes in carbon monoxide imaging. Furthermore, these wide-angled systems exhibit unusually high abundances of the molecular ion HCO+. We present results from a chemodynamic model of such regions where a rich chemistry arises naturally as a result of turbulent mixing between cold, dense molecular gas and the hot, ionized outflow material. The injecta drives a rich and rapid ion-neutral chemistry in qualitative and quantitative agreement with the observations. The observational bias towards wide-angled outflows is explained naturally by the geometry-dependent ion injection rate causing rapid dissociation of CO in the younger systems.

Use of a microscope-mounted wide-angle point of view camera to record optimal hand position in ocular surgery.

PubMed

Gooi, Patrick; Ahmed, Yusuf; Ahmed, Iqbal Ike K

2014-07-01

We describe the use of a microscope-mounted wide-angle point-of-view camera to record optimal hand positions in ocular surgery. The camera is mounted close to the objective lens beneath the surgeon's oculars and faces the same direction as the surgeon, providing a surgeon's view. A wide-angle lens enables viewing of both hands simultaneously and does not require repositioning the camera during the case. Proper hand positioning and instrument placement through microincisions are critical for effective and atraumatic handling of tissue within the eye. Our technique has potential in the assessment and training of optimal hand position for surgeons performing intraocular surgery. It is an innovative way to routinely record instrument and operating hand positions in ophthalmic surgery and has minimal requirements in terms of cost, personnel, and operating-room space. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Evaluation of the Association Between Common Genetic Variants Near the ABCA1 Gene and Primary Angle Closure Glaucoma in a Han Chinese Population.

PubMed

Luo, Huaichao; Chen, Yuhong; Ye, Zimeng; Sun, Xinghuai; Shi, Yi; Luo, Qian; Gong, Bo; Shuai, Ping; Yang, Jiyun; Zhou, Yu; Liu, Xiaoqi; Zhang, Kaijiong; Tan, Chang; Li, Yuanfeng; Lin, Ying; Yang, Zhenglin

2015-10-01

Recently, three large genome-wide association studies have identified multiple variants associated with primary open angle glaucoma (POAG) near the ABCA1 gene. Considering that POAG and primary angle closure glaucoma (PACG) share many similar clinical manifestations, the present study was conducted to investigate whether these genetic variants were also associated with PACG in a Han Chinese population. A case-control association study of 1122 cases (PACG/PAC) and 1311 normal, matched controls was undertaken. Seven single-nucleotide polymorphisms (SNPs) near the ABCA1 gene, including rs2422493, rs2487042, rs2472496, rs2472493, rs2487032, rs2472459, and rs2472519, were genotyped. Genotype and allele frequencies were assessed using χ² tests. Linkage disequilibrium (LD) structure was analyzed by computer software. Among the SNPs genotyped, no association was observed between these SNPs and PACG. However, we discovered that two haplotypes, CATTTAC (corrected P = 0.048) and CGCCCGC (corrected P = 0.048), remained significantly associated with PACG/PAC after Bonferroni correction. Subjects with the CATTTAC haplotype have a 1.71-fold increased possibility of having PACG/PAC, whereas subjects with the CGCCCGC haplotype have 0.47-fold decreased possibility of developing PACG. Our findings suggest that the genetic backgrounds of PACG and POAG might be different. However, whether or not ABCA1 plays a role in the development of PACG is still not made certain by this study. Thus, further research is needed to find the role of ABCA1 in the progress of PACG.

Large-visual-angle microstructure inspired from quantitative design of Morpho butterflies' lamellae deviation using the FDTD/PSO method.

PubMed

Wang, Wanlin; Zhang, Wang; Chen, Weixin; Gu, Jiajun; Liu, Qinglei; Deng, Tao; Zhang, Di

2013-01-15

The wide angular range of the treelike structure in Morpho butterfly scales was investigated by finite-difference time-domain (FDTD)/particle-swarm-optimization (PSO) analysis. Using the FDTD method, different parameters in the Morpho butterflies' treelike structure were studied and their contributions to the angular dependence were analyzed. Then a wide angular range was realized by the PSO method from quantitatively designing the lamellae deviation (Δy), which was a crucial parameter with angular range. The field map of the wide-range reflection in a large area was given to confirm the wide angular range. The tristimulus values and corresponding color coordinates for various viewing directions were calculated to confirm the blue color in different observation angles. The wide angular range realized by the FDTD/PSO method will assist us in understanding the scientific principles involved and also in designing artificial optical materials.

Proximal opening wedge osteotomy with wedge-plate fixation compared with proximal chevron osteotomy for the treatment of hallux valgus: a prospective, randomized study.

PubMed

Glazebrook, Mark; Copithorne, Peter; Boyd, Gordon; Daniels, Timothy; Lalonde, Karl-André; Francis, Patricia; Hickey, Michael

2014-10-01

Hallux valgus with an increased intermetatarsal angle is usually treated with a proximal metatarsal osteotomy. The proximal chevron osteotomy is commonly used but is technically difficult. This study compares the proximal opening wedge osteotomy of the first metatarsal with the proximal chevron osteotomy for the treatment of hallux valgus with an increased intermetatarsal angle. This prospective, randomized multicenter (three-center) study was based on the clinical outcome scores of the Short Form-36, the American Orthopaedic Foot & Ankle Society forefoot questionnaire, and the visual analog scale for pain, activity, and patient satisfaction. Subjects were assessed prior to surgery and at three, six, and twelve months postoperatively. Surgeon preference was evaluated based on questionnaires and the operative times required for each procedure. No significant differences were found for any of the patients' clinical outcome measurements between the two procedures. The proximal opening wedge osteotomy was found to lengthen, and the proximal chevron osteotomy was found to shorten, the first metatarsal. The intermetatarsal angles improved (decreased) significantly, from 14.8° ± 3.2° to 9.1° ± 2.9 (mean and standard deviation) after a proximal opening wedge osteotomy and from 14.6° ± 3.9° to 11.3° ± 4.0° after a proximal chevron osteotomy (p < 0.05 for both). Operative time required for performing a proximal opening wedge osteotomy is similar to that required for performing a proximal chevron osteotomy (mean and standard deviation, 67.1 ± 16.5 minutes compared with 69.9 ± 18.6 minutes; p = 0.510). Opening wedge and proximal chevron osteotomies have comparable radiographic outcomes and comparable clinical outcomes for pain, satisfaction, and function. The proximal opening wedge osteotomy lengthens, and the proximal chevron osteotomy shortens, the first metatarsal. The proximal opening wedge osteotomy was subjectively less technically demanding and was preferred by the orthopaedic surgeons in this study. Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2014 by The Journal of Bone and Joint Surgery, Incorporated.

Efficacy and tolerability of brinzolamide/brimonidine suspension and prostaglandin analogs in patients previously treated with dorzolamide/timolol solution and prostaglandin analogs.

PubMed

Lo, Jonathan S; Pang, Pierre M; Lo, Samuel C

2016-01-01

Fixed combination glaucoma medication is increasingly used in glaucoma treatment. There is a lack of comparative study in the literature of non-beta blocker combination agents used adjunctively with a glaucoma agent in a different class. The objective of this study is to evaluate the effect of intraocular pressure (IOP) control and tolerability of non-beta blocker combination suspension with prostaglandin analogs (PGA) in patients with open angle glaucoma who were previously treated with beta blocker combination solution with PGA. Open-label retrospective review of patient records. This study looked at patients with open angle glaucoma taking dorzolamide/timolol solution with PGA that were switched to brinzolamide/brimonidine combination suspension with PGA. This study reviewed the charts of all patients who were at least 21 years old with a clinical diagnosis of open-angle glaucoma or ocular hypertension in at least one eye. Patients needed to have been treated with concomitant use of PGA and dorzolamide/timolol solution for at least one month. Patients using dorzolamide/timolol solution plus PGA with medication related ocular irritation were switched to brinzolamide/brimonidine suspension with the same PGA. Best-corrected visual acuity, ocular hyperemia grading, slit lamp biomicroscopy and Goldmann applanation tonometry measurements, and patient medication preferences were assessed at baseline, 1 month and 3 months. Forty eyes with open angle glaucoma. The mean age of the patients was 68 and 60% were females. The IOP before the switch was 17.2 and 16.5 (P=0.70) following the switch at 3 months. We found a decreasing trend of ocular hyperemia (P=0.064) and strong preference (P=0.011) for non-beta blocker combination suspension but no difference of visual acuity and slit lamp findings. Brinzolamide/brimonidine combination suspension when used adjunctively with PGA is equally effective. Patients in this study reported greatly reduced ocular redness and shorter duration of stinging with non-beta blocker combination suspension. Their preference of it over dorzolamide/timolol combination solution makes it a viable treatment option, particularly for the aging glaucoma patient with comorbidities that restrict the beta blocker use.

Tension Strength, Failure Prediction and Damage Mechanisms in 2D Triaxial Braided Composites with Notch

NASA Technical Reports Server (NTRS)

Norman, Timothy L.; Anglin, Colin

1995-01-01

The unnotched and notched (open hole) tensile strength and failure mechanisms of two-dimensional (2D) triaxial braided composites were examined. The effect of notch size and notch position were investigated. Damage initiation and propagation in notched and unnotched coupons were also examined. Theory developed to predict the normal stress distribution near an open hole and failure for tape laminated composites was evaluated for its applicability to 2D triaxial braided textile composite materials. Four different fiber architectures were considered; braid angle, yarn and braider size, percentage of longitudinal yarns and braider angle varied. Tape laminates equivalent to textile composites were also constructed for comparison. Unnotched tape equivalents were stronger than braided textiles but exhibited greater notch sensitivity. Notched textiles and tape equivalents have roughly the same strength at large notch sizes. Two common damage mechanisms were found: braider yarn cracking and near notch longitudinal yarn splitting. Cracking was found to initiate in braider yarns in unnotched and notched coupons, and propagate in the direction of the braider yarns until failure. Damage initiation stress decreased with increasing braid angle. No significant differences in prediction of near notch strain between textile and tape equivalents could be detected for small braid angle, but the correlations were weak for textiles with large braid angle. Notch strength could not be predicted using existing anisotropic theory for braided textiles due to their insensitivity to notch.

Practical Tests with the "auto Control Slot." Part II : Discussion

NASA Technical Reports Server (NTRS)

Lachmann, G

1930-01-01

For some time the D.V.L. has been investigating the question of applicability of Handley Page slotted wings to German airplanes. Comparitive gliding tests were made with open and closed slots on an Albatros L 75 airplane equipped with the Handley Page "auto control slots." This investigation served to determine the effect of the auto control slot on the properties and performances of airplanes at large angles of attack. The most important problems were whether the angle of glide at small angles of attack can be increased by the adoption of the auto control slot and, in particular, as to whether the flight characteristics at large angles of attack are improved thereby and equilibrium in gliding flight is guaranteed even at larger than ordinary angles of attack.

Practical Tests with the "auto Control Slot." Part I : Lecture

NASA Technical Reports Server (NTRS)

Lachmann, G

1930-01-01

For some time the D.V.L. has been investigating the question of applicability of Handley Page slotted wings to German airplanes. Comparitive gliding tests were made with open and closed slots on an Albatros L 75 airplane equipped with the Handley Page "auto control slots." This investigation served to determine the effect of the auto control slot on the properties and performances of airplanes at large angles of attack. The most important problems were whether the angle of glide at small angles of attack can be increased by the adoption of the auto control slot and, in particular, as to whether the flight characteristics at large angles of attack are improved thereby and equilibrium in gliding flight is guaranteed even at larger than ordinary angles of attack.

Detection of Clinically Significant Retinopathy of Prematurity Using Wide-angle Digital Retinal Photography

PubMed Central

Chiang, Michael F.; Melia, Michele; Buffenn, Angela N.; Lambert, Scott R.; Recchia, Franco M.; Simpson, Jennifer L.; Yang, Michael B.

2013-01-01

Objective To evaluate the accuracy of detecting clinically significant retinopathy of prematurity (ROP) using wide-angle digital retinal photography. Methods Literature searches of PubMed and the Cochrane Library databases were conducted last on December 7, 2010, and yielded 414 unique citations. The authors assessed these 414 citations and marked 82 that potentially met the inclusion criteria. These 82 studies were reviewed in full text; 28 studies met inclusion criteria. The authors extracted from these studies information about study design, interventions, outcomes, and study quality. After data abstraction, 18 were excluded for study deficiencies or because they were superseded by a more recent publication. The methodologist reviewed the remaining 10 studies and assigned ratings of evidence quality; 7 studies were rated level I evidence and 3 studies were rated level III evidence. Results There is level I evidence from ≥5 studies demonstrating that digital retinal photography has high accuracy for detection of clinically significant ROP. Level III studies have reported high accuracy, without any detectable complications, from real-world operational programs intended to detect clinically significant ROP through remote site interpretation of wide-angle retinal photographs. Conclusions Wide-angle digital retinal photography has the potential to complement standard ROP care. It may provide advantages through objective documentation of clinical examination findings, improved recognition of disease progression by comparing previous photographs, and the creation of image libraries for education and research. Financial Disclosure(s) Proprietary or commercial disclosure may be found after the references. PMID:22541632

Highly Collimated Jets and Wide-angle Outflows in HH 46/47: New Evidence from Spitzer Infrared Images

NASA Technical Reports Server (NTRS)

Velusamy, T.; Langer, William D.; Marsh, Kenneth. A.

2007-01-01

We present new details of the structure and morphology of the jets and outflows in HH 46/47 as seen in Spitzer infrared images from IRAC and MIPS, reprocessed using the 'HiRes' deconvolution technique. HiRes improves the visualization of spatial morphology by enhancing resolution (to subarcsecond levels in IRAC bands) and removing the contaminating side lobes from bright sources. In addition to sharper views of previously reported bow shocks, we have detected (1) the sharply delineated cavity walls of the wide-angle biconical outflow, seen in scattered light on both sides of the protostar, (2) several very narrow jet features at distances approximately 400 AU to approximately 0.1 pc from the star, and (3) compact emissions at MIPS 24 m with the jet heads, tracing the hottest atomic/ionic gas in the bow shocks. Together the IRAC and MIPS images provide a more complete picture of the bow shocks, tracing both the molecular and atomic/ionic gases, respectively. The narrow width and alignment of all jet-related features indicate a high degree of jet collimation and low divergence (width of approximately 400 AU increasing by only a factor of 2.3 over 0.2 pc). The morphology of this jet, bow shocks, wide-angle outflows, and the fact that the jet is nonprecessing and episodic, constrain the mechanisms for producing the jet's entrained molecular gas, and origins of the fast jet, and slower wide-angle outflow.

Wide Angle Movie

NASA Technical Reports Server (NTRS)

1999-01-01

This brief movie illustrates the passage of the Moon through the Saturn-bound Cassini spacecraft's wide-angle camera field of view as the spacecraft passed by the Moon on the way to its closest approach with Earth on August 17, 1999. From beginning to end of the sequence, 25 wide-angle images (with a spatial image scale of about 14 miles per pixel (about 23 kilometers)were taken over the course of 7 and 1/2 minutes through a series of narrow and broadband spectral filters and polarizers, ranging from the violet to the near-infrared regions of the spectrum, to calibrate the spectral response of the wide-angle camera. The exposure times range from 5 milliseconds to 1.5 seconds. Two of the exposures were smeared and have been discarded and replaced with nearby images to make a smooth movie sequence. All images were scaled so that the brightness of Crisium basin, the dark circular region in the upper right, is approximately the same in every image. The imaging data were processed and released by the Cassini Imaging Central Laboratory for Operations (CICLOPS)at the University of Arizona's Lunar and Planetary Laboratory, Tucson, AZ.

Photo Credit: NASA/JPL/Cassini Imaging Team/University of Arizona

Cassini, launched in 1997, is a joint mission of NASA, the European Space Agency and Italian Space Agency. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

25G compared with 20G vitrectomy under Resight non-contact wide-angle lenses for Terson syndrome.

PubMed

Mao, Xinbang; You, Zhipeng

2017-08-01

The aim of the present study was to compare the effectiveness of 25G vitrectomy to standard 20G vitrectomy for treatment of Terson syndrome under Resight non-contact wide-angle lenses. This was a case-control study of 20 patients with Terson syndrome (study group) that underwent 25G vitrectomy under Resight non-contact wide-angle lenses, with those of 20 matched patients that underwent 20G vitrectomy (control group). Medical records were reviewed from between July 2011 and October 2013. Data included results of the Early Treatment Diabetic Retinopathy Study examination, ophthalmology B-scan ultrasonography and fundus photography. The mean age, follow-up time, the preoperative visual acuity of LogMAR and the preoperative intraocular pressure (IOP) were all comparable in the two groups (all P>0.05). There were statistically significant differences in postoperative visual acuity of LogMAR compared with preoperative visual acuity (P<0.001) in both groups, but no difference between the groups (P=0.845). However, the operative times (13.5 min in study group vs. 42 min in control group) and post-operative IOP at day 1 (13.5 vs. 20 mmHg) were significantly reduced in the study group compared to the control group (P<0.001). Therefore, the present findings suggest that 25G Vitrectomy for Terson syndrome under Resight non-contact wide-angle lenses can achieve a significantly shorter operative time and lower post-operative IOP compared with 20G Vitrectomy.

Optimum take-off angle in the long jump.

PubMed

Linthorne, Nicholas P; Guzman, Maurice S; Bridgett, Lisa A

2005-07-01

In this study, we found that the optimum take-off angle for a long jumper may be predicted by combining the equation for the range of a projectile in free flight with the measured relations between take-off speed, take-off height and take-off angle for the athlete. The prediction method was evaluated using video measurements of three experienced male long jumpers who performed maximum-effort jumps over a wide range of take-off angles. To produce low take-off angles the athletes used a long and fast run-up, whereas higher take-off angles were produced using a progressively shorter and slower run-up. For all three athletes, the take-off speed decreased and the take-off height increased as the athlete jumped with a higher take-off angle. The calculated optimum take-off angles were in good agreement with the athletes' competition take-off angles.

Jet creation in post-AGB binaries: the circum-companion accretion disk around BD+46°442

NASA Astrophysics Data System (ADS)

Bollen, Dylan; Van Winckel, Hans; Kamath, Devika

2017-11-01

Aims: We aim at describing and understanding binary interaction processes in systems with very evolved companions. Here, we focus on understanding the origin and determining the properties of the high-velocity outflow observed in one such system. Methods: We present a quantitative analysis of BD+46°442, a post-AGB binary that shows active mass transfer that leads to the creation of a disk-driven outflow or jet. We obtained high-resolution optical spectra from the HERMES spectrograph, mounted on the 1.2 m Flemish Mercator Telescope. By performing a time-series analysis of the Hα profile, we identified the different components of the system. We deduced the jet geometry by comparing the orbital phased data with our jet model. In order to image the accretion disk around the companion of BD+46°442, we applied the technique of Doppler tomography. Results: The orbital phase-dependent variations in the Hα profile can be related to an accretion disk around the companion, from which a high-velocity outflow or jet is launched. Our model shows that there is a clear correlation between the inclination angle and the jet opening angle. The latitudinally dependent velocity structure of our jet model shows a good correspondence to the data, with outflow velocities higher than at least 400 km s-1. The intensity peak in the Doppler map might be partly caused by a hot spot in the disk, or by a larger asymmetrical structure in the disk. Conclusions: We show that BD+46°442 is a result of a binary interaction channel. The origin of the fast outflow in this system might be to a gaseous disk around the secondary component, which is most likely a main-sequence star. Our analysis suggests that the outflow has a rather wide opening angle and is not strongly collimated. Our time-resolved spectral monitoring reveals the launching site of the jet in the binary BD+46°442. Similar orbital phase-dependent Hα profiles are commonly observed in post-AGB binaries. Post-AGB binaries provide ideal test beds to study jet formation and launching mechanisms over a wide range of orbital conditions. Based on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemmish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.The reduced spectra (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/607/A60

Open conformation of a substrate-binding cleft: sup 19 F NMR studies of cleft angle in the D-galactose chemosensory receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luck, L.A.; Falke, J.J.

1991-07-02

The Escherichia coli D-galactose and D-glucose receptor is a two-domain structure with a sugar-binding site at the interface between domains. The structure of the closed cleft containing bound D-glucose has been determined crystalloghraphically, but the open cleft remains to be characterized. The present study illustrates a generalizable approach that is used to detect and analyze both the open- and closed-cleft conformations in solution. A {sup 19}F nucleus located inside the cleft is monitored by {sup 19}F NMR. When the cleft is occupied by D-glucose, the {sup 19}F nucleus is found to be inaccessible to the aqueous paramagnetic probe Gd{center dot}EDTA,more » verifying that the occupied cleft is closed in solution and inaccessible to bulk solvent. When the cleft is empty, the {sup 19}F nucleus becomes accessible to the paramagnet such that the distance of closest approach is r {le} 10 {angstrom}, indicating that the empty cleft opens at least transiently by an angle {theta} {ge} 18 {plus minus} 3{degrees}.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mizuta, Akira; Ioka, Kunihito

We investigate the jet propagation and breakout from the stellar progenitor for gamma-ray burst (GRB) collapsars by performing two-dimensional relativistic hydrodynamic simulations and analytical modeling. We find that the jet opening angle is given by θ{sub j} ∼ 1/5Γ{sub 0} and infer the initial Lorentz factor of the jet at the central engine, Γ{sub 0}, is a few for existing observations of θ{sub j}. The jet keeps the Lorentz factor low inside the star by converging cylindrically via collimation shocks under the cocoon pressure and accelerates at jet breakout before the free expansion to a hollow-cone structure. In this newmore » picture, the GRB duration is determined by the sound crossing time of the cocoon, after which the opening angle widens, reducing the apparent luminosity. Some bursts violating the maximum opening angle θ{sub j,{sub max}} ∼ 1/5 ∼ 12° imply the existence of a baryon-rich sheath or a long-acting jet. We can explain the slopes in both Amati and Yonetoku spectral relations using an off-centered photosphere model, if we make only one assumption that the total jet luminosity is proportional to the initial Lorentz factor of the jet. We also numerically calibrate the pre-breakout model (Bromberg et al.) for later use.« less

Examining Delay Intervals in the Diagnosis and Treatment of Primary Open Angle Glaucoma in an Egyptian Population and Its Impact on Lifestyle

PubMed Central

Abu Hussein, Nahla B.; Habib, Ahmed E.; El Sayed, Yasmine M.

2016-01-01

Purpose. To examine causes as well as extent of delay in diagnosis and treatment of primary open angle glaucoma patients in a sample of Egyptians. Patients and Methods. 440 patients with primary open angle glaucoma were interviewed to evaluate delay in their diagnosis and treatment. The extent and cause of delay were investigated. The total delay interval, if any, was correlated with socioeconomic and other factors. Results. The median total delay was one year, with 50% of patients having a total delay of 1 year or less, of which 25% exhibited zero total delay. 25% of patients had a delay ranging from 1 to 3 years, and 25% had a total delay ranging from 3 to 27 years. Diagnostic delay accounted for 43.03% of cases. Longer delays were met in patients with certain socioeconomic factors. Patients with a positive family history of glaucoma displayed shorter delay periods. Conclusion. Significant delay in the diagnosis and treatment of glaucoma was found. Poor socioeconomic status seems to hinder timely diagnosis and treatment of POAG. Certain socioeconomic factors seem to correlate with the extent of delay. More effort is thus needed to subsidize the cost of investigations and treatment for glaucoma patients. PMID:28116140

Modifiable factors in the management of glaucoma: a systematic review of current evidence.

PubMed

Hecht, Idan; Achiron, Asaf; Man, Vitaly; Burgansky-Eliash, Zvia

2017-04-01

Primary open angle glaucoma is a chronic optic neuropathy affecting millions of people worldwide and represents a major public health issue. Environmental factors, behaviors, and diet are intimately related to patient health and may play a role in the pathogenesis and progression of glaucoma. This study aims to review the literature, focusing on the last three years, regarding modifiable lifestyle interventions in the management of primary open angle glaucoma. Electronic databases were searched for studies published between January 2013 and July 2016 on the topic of lifestyle interventions in primary open angle glaucoma. Sleeping with the head elevated and avoiding the worst eye-dependent side during sleep may slightly lower intraocular pressure and reduce visual field loss. Some food supplements and moderate aerobic exercise may also reduce intraocular pressure up to 2.0 and 3.0 mmHg, respectively. Frequency of coffee intake may be associated with disease progression. Potential negative effects are associated with weight-lifting and yoga exercises. Certain lifestyle habits could influence glaucoma progression, yet no specific interventions are currently supported by robust evidence. Awareness of the possible influences of certain habits should help guide clinical advice and is important to help patients avoid adverse outcomes and take an active role in the management of their disease.

First-line treatment for elevated intraocular pressure (IOP) associated with open-angle glaucoma or ocular hypertension: focus on bimatoprost

PubMed Central

Law, Simon K

2007-01-01

The goal of treatment for open-angle glaucoma or ocular hypertension is to improve quality of life through reduction of intraocular pressure (IOP) to preserve visual function. Prostaglandins, as a newer class of ocular hypotensive agents, have been shown to be effective in IOP reduction by the primary mechanism of action of increase the uveoscleral outflow. Bimatoprost is a member this class, but different from the other members by having an ethyl amide group rather than an isopropyl ester at the C-1 carbon of the alpha chain. Bimatoprost used once daily has been shown to be more effect in IOP reduction than other classes of topical ocular hypotensive agents including beta-blockers, carbonic anhydrase inhibitors, and alpha agonists. Comparing with other topical prostaglandins, bimatoprost may be slightly more effective in IOP reduction, but the clinical significance is uncertain. The commonly reported adverse events associated with bimatoprost are localized to the eye and include conjunctival hyperemia, changes in the pigmentation of the periocular skin and iris, and eyelash darkening and growth. It is currently approved by the Food and Drug Administration (FDA) and the European Commission (EC) for first-line therapy for the reduction of elevated IOP in patients with open-angle glaucoma or ocular hypertension. PMID:19668476

Spatial hearing in Cope’s gray treefrog: I. Open and closed loop experiments on sound localization in the presence and absence of noise

PubMed Central

Caldwell, Michael S.; Bee, Mark A.

2014-01-01

The ability to reliably locate sound sources is critical to anurans, which navigate acoustically complex breeding choruses when choosing mates. Yet, the factors influencing sound localization performance in frogs remain largely unexplored. We applied two complementary methodologies, open and closed loop playback trials, to identify influences on localization abilities in Cope’s gray treefrog, Hyla chrysoscelis. We examined localization acuity and phonotaxis behavior of females in response to advertisement calls presented from 12 azimuthal angles, at two signal levels, in the presence and absence of noise, and at two noise levels. Orientation responses were consistent with precise localization of sound sources, rather than binary discrimination between sources on either side of the body (lateralization). Frogs were unable to discriminate between sounds arriving from forward and rearward directions, and accurate localization was limited to forward sound presentation angles. Within this region, sound presentation angle had little effect on localization acuity. The presence of noise and low signal-to-noise ratios also did not strongly impair localization ability in open loop trials, but females exhibited reduced phonotaxis performance consistent with impaired localization during closed loop trials. We discuss these results in light of previous work on spatial hearing in anurans. PMID:24504182

Stent conformity in curved vascular models with simulated aneurysm necks using flat-panel CT: an in vitro study.

PubMed

Ebrahimi, N; Claus, B; Lee, C-Y; Biondi, A; Benndorf, G

2007-05-01

Radiographic visibility of self-expandable intracranial stents is insufficient for assessment of conformability and deployment characteristics. The purpose of this study was to evaluate stent mechanics in a curved vessel model by using Flat-Panel CT (FPCT). The following stents were used: Neuroform 2, Neuroform Treo, Enterprise, and LEO. All stents were bent in the same polytetrafluoroethylene tubes with various angles ranging from 150 degrees to 30 degrees . To visualize potential prolapse of the stent struts, 4-, 5-, and 8-mm openings were created. FPCTs were obtained using a C-arm with flat detector. FPCT scans provided excellent visualization of deployment characteristics and stent mechanics and was superior to digital subtraction angiography (DSA) and digital radiography (DR). The Neuroform2/Treo showed, with increasing angle and diameter of the opening, a continuous increase in cell size. These stents also showed an outward prolapse at the convexity and an inwards prolapse of struts at the concavity of the curvature. The Enterprise showed an increasing trend to flatten and to kink with curvatures that are more acute. The LEO showed fewer trends to kink but an inward crimping of its ends with more acute angles. Deployment characteristics and conformability to a curved vessel model vary considerably, depending on the angle and the stent design. Adverse mechanics such as increased cell opening, strut prolapse, flattening, and kinking occur during stent placement in a curved vessel model, and may gain clinical importance. FPCT is superior to DSA and DR in visualizing small metallic stents and enables accurate detection of adverse stent mechanics.

Multiplicative Quaternion Extended Kalman Filtering for Nonspinning Guided Projectiles

DTIC Science & Technology

2013-07-01

tactical applications are inertial. The advantages of using quaternions rather than Euler angles to represent projectile attitude are discussed, and...projectiles generally don’t experience a wide range of heading angles , this has not a primary concern. The other major advantage of quaternions (or...DCMs) over Euler angles is their propagation equations are linear with respect to the quaternion and only depend on the IMU’s angular velocity. This

Structure of gel phase DMPC determined by X-ray diffraction.

PubMed Central

Tristram-Nagle, Stephanie; Liu, Yufeng; Legleiter, Justin; Nagle, John F

2002-01-01

The structure of fully hydrated gel phase dimyristoylphosphatidylcholine lipid bilayers was obtained at 10 degrees C. Oriented lipid multilayers were used to obtain high signal-to-noise intensity data. The chain tilt angle and an estimate of the methylene electron density were obtained from wide angle reflections. The chain tilt angle is measured to be 32.3 +/- 0.6 degrees near full hydration, and it does not change as the sample is mildly dehydrated from a repeat spacing of D = 59.9 A to D = 56.5 A. Low angle diffraction peaks were obtained up to the tenth order for 17 samples with variable D and prepared by three different methods with different geometries. In addition to the usual Fourier reconstructions of the electron density profiles, model electron density profiles were fit to all the low angle data simultaneously while constraining the model to include the wide-angle data and the measured lipid volume. Results are obtained for area/lipid (A = 47.2 +/- 0.5 A(2)), the compressibility modulus (K(A) = 500 +/- 100 dyn/cm), various thicknesses, such as the hydrocarbon thickness (2D(C) = 30.3 +/- 0.2 A), and the head-to-head spacing (D(HH) = 40.1 +/- 0.1 A). PMID:12496100

Omni-Directional Viewing-Angle Switching through Control of the Beam Divergence Angle in a Liquid Crystal Panel

NASA Astrophysics Data System (ADS)

Baek, Jong-In; Kim, Ki-Han; Kim, Jae Chang; Yoon, Tae-Hoon

2010-01-01

This paper proposes a method of omni-directional viewing-angle switching by controlling the beam diverging angle (BDA) in a liquid crystal (LC) panel. The LCs aligned randomly by in-cell polymer structures diffuse the collimated backlight for the bright state of the wide viewing-angle mode. We align the LCs homogeneously by applying an in-plane field for the narrow viewing-angle mode. By doing this the scattering is significantly reduced so that the small BDA is maintained as it passes through the LC layer. The dark state can be obtained by aligning the LCs homeotropically with a vertical electric field. We demonstrated experimentally the omni-directional switching of the viewing-angle, without an additional panel or backlighting system.

Contact angle determination procedure and detection of an invisible surface film

NASA Technical Reports Server (NTRS)

Meyer, G.; Grat, R.

1990-01-01

The contact angle value, i.e., the tangent angle of liquid resting on a planar solid surface, is a basic parameter which can be applied to a wide range of applications. The goal is to provide a basic understanding of the contact angle measurement technique and to present a simple illustration that can be applied as a quality control method; namely, detection of a surface contaminant which exists on a surface that appears clean to the unaided eye. The equipment and experimental procedures are detailed.

[Predicting the probability of development and progression of primary open angle glaucoma by regression modeling].

PubMed

Likhvantseva, V G; Sokolov, V A; Levanova, O N; Kovelenova, I V

2018-01-01

Prediction of the clinical course of primary open-angle glaucoma (POAG) is one of the main directions in solving the problem of vision loss prevention and stabilization of the pathological process. Simple statistical methods of correlation analysis show the extent of each risk factor's impact, but do not indicate the total impact of these factors in personalized combinations. The relationships between the risk factors is subject to correlation and regression analysis. The regression equation represents the dependence of the mathematical expectation of the resulting sign on the combination of factor signs. To develop a technique for predicting the probability of development and progression of primary open-angle glaucoma based on a personalized combination of risk factors by linear multivariate regression analysis. The study included 66 patients (23 female and 43 male; 132 eyes) with newly diagnosed primary open-angle glaucoma. The control group consisted of 14 patients (8 male and 6 female). Standard ophthalmic examination was supplemented with biochemical study of lacrimal fluid. Concentration of matrix metalloproteinase MMP-2 and MMP-9 in tear fluid in both eyes was determined using 'sandwich' enzyme-linked immunosorbent assay (ELISA) method. The study resulted in the development of regression equations and step-by-step multivariate logistic models that can help calculate the risk of development and progression of POAG. Those models are based on expert evaluation of clinical and instrumental indicators of hydrodynamic disturbances (coefficient of outflow ease - C, volume of intraocular fluid secretion - F, fluctuation of intraocular pressure), as well as personalized morphometric parameters of the retina (central retinal thickness in the macular area) and concentration of MMP-2 and MMP-9 in the tear film. The newly developed regression equations are highly informative and can be a reliable tool for studying of the influence vector and assessment of pathogenic potential of the independent risk factors in specific personalized combinations.

Dual-mode switching of a liquid crystal panel for viewing angle control

NASA Astrophysics Data System (ADS)

Baek, Jong-In; Kwon, Yong-Hoan; Kim, Jae Chang; Yoon, Tae-Hoon

2007-03-01

The authors propose a method to control the viewing angle of a liquid crystal (LC) panel using dual-mode switching. To realize both wide viewing angle (WVA) characteristics and narrow viewing angle (NVA) characteristics with a single LC panel, the authors use two different dark states. The LC layer can be aligned homogeneously parallel to the transmission axis of the bottom polarizer for WVA dark state operation, while it can be aligned vertically for NVA dark state operation. The authors demonstrated that viewing angle control can be achieved with a single panel without any loss of contrast at the front.

Observations of Solar Energetic Particles from 3He-rich Events over a Wide Range of Heliographic Longitude

NASA Astrophysics Data System (ADS)

Wiedenbeck, M. E.; Mason, G. M.; Cohen, C. M. S.; Nitta, N. V.; Gómez-Herrero, R.; Haggerty, D. K.

2013-01-01

A prevailing model for the origin of 3He-rich solar energetic particle (SEP) events attributes particle acceleration to processes associated with the reconnection between closed magnetic field lines in an active region and neighboring open field lines. The open field from the small reconnection volume then provides a path along which accelerated particles escape into a relatively narrow range of angles in the heliosphere. The narrow width (standard deviation <20°) of the distribution of X-ray flare longitudes found to be associated with 3He-rich SEP events detected at a single spacecraft at 1 AU supports this model. We report multispacecraft observations of individual 3He-rich SEP events that occurred during the solar minimum time period from 2007 January through 2011 January using instrumentation carried by the two Solar Terrestrial Relations Observatory spacecraft and the Advanced Composition Explorer. We find that detections of 3He-rich events at pairs of spacecraft are not uncommon, even when their longitudinal separation is >60°. We present the observations of the 3He-rich event of 2010 February 7, which was detected at all three spacecraft when they spanned 136° in heliographic longitude. Measured fluences of 3He in this event were found to have a strong dependence on longitude which is well fit by a Gaussian with standard deviation ~48° centered at the longitude that is connected to the source region by a nominal Parker spiral magnetic field. We discuss several mechanisms for distributing flare-accelerated particles over a wide range of heliographic longitudes including interplanetary diffusion perpendicular to the magnetic field, spreading of a compact cluster of open field lines between the active region and the source surface where the field becomes radial and opens out into the heliosphere, and distortion of the interplanetary field by a preceding coronal mass ejection. Statistical studies of additional 3He-rich events detected at multiple spacecraft will be needed to establish the relative importance of the various mechanisms.

Wind-tunnel investigation of several high aspect-ratio supercritical wing configurations on a wide-body-type fuselage

NASA Technical Reports Server (NTRS)

Bartlett, D. W.

1977-01-01

An investigation was conducted in the Langley 8-foot transonic pressure tunnel on two aspect-ratio 11.95 supercritical wings that were tested in combination with a representative wide-body-type fuselage. The two supercritical wings have identical planforms for equal sweep angles and differ only in thickness. Each wing was tested at quarter-chord sweep angles of 27 deg and 30 deg. At the higher sweep angle, the aspect ratio is reduced to 11.36. At 27 deg of quarter-chord sweep, the thicker supercritical wing (SCW-1) has maximum streamwise thickness-to-chord ratios of 0.16 at the wing-fuselage juncture, 0.14 at the planform break station, and 0.12 at the tip. The thinner wing (SCW-2) has maximum streamwise thickness-to-chord ratios of 0.144, 0.12, and 0.10 at the same stations respectively. Tests were also conducted on the thinner supercritical wing at the 27 deg sweep angle with a 15.24 cm (6.0 in.) shorter span which results in an aspect ratio of 10.25. For comparison, data were obtained on a current wide-body transport wing (AR=7) that was tested on the same fuselage used with the supercritical wings.

Brønsted acid sites based on penta-coordinated aluminum species

NASA Astrophysics Data System (ADS)

Wang, Zichun; Jiang, Yijiao; Lafon, Olivier; Trébosc, Julien; Duk Kim, Kyung; Stampfl, Catherine; Baiker, Alfons; Amoureux, Jean-Paul; Huang, Jun

2016-12-01

Zeolites and amorphous silica-alumina (ASA), which both provide Brønsted acid sites (BASs), are the most extensively used solid acid catalysts in the chemical industry. It is widely believed that BASs consist only of tetra-coordinated aluminum sites (AlIV) with bridging OH groups in zeolites or nearby silanols on ASA surfaces. Here we report the direct observation in ASA of a new type of BAS based on penta-coordinated aluminum species (AlV) by 27Al-{1H} dipolar-mediated correlation two-dimensional NMR experiments at high magnetic field under magic-angle spinning. Both BAS-AlIV and -AlV show a similar acidity to protonate probe molecular ammonia. The quantitative evaluation of 1H and 27Al sites demonstrates that BAS-AlV co-exists with BAS-AlIV rather than replaces it, which opens new avenues for strongly enhancing the acidity of these popular solid acids.

Narrowband thermal radiation from closed-end microcavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohiyama, Asaka; Shimizu, Makoto; Iguchi, Fumitada

2015-10-07

High spectral selectivity of thermal radiation is important for achieving high-efficiency energy systems. In this study, intense, narrowband, and low directional absorption/radiation were observed in closed-end microcavity which is a conventional open-end microcavity covered by a semi-transparent thin metal film. The quality factor (Q factor) of optical absorption band strongly depended on the film electrical conductivity. Asymmetric and narrow absorption band with a Q factor of 25 at 1.28 μm was obtained for a 6-nm-thick Au film. Numerical simulations suggest that the formation of a fixed-end mode at the cavity aperture contributes to the narrowband optical absorption. The closed-end microcavity filledmore » with SiO{sub 2} exhibits intense and isotropic thermal radiation over a wide solid angle according to numerical simulation. The narrow and asymmetric absorption spectrum was experimentally confirmed in a model of closed-end microcavity.« less

Peel/seal properties of poly(ethylene methyl acrylate)/polybutene-1 blend films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohammdi, Seyedeh Raziyeh; Ajji, Abdellah; Tabatabaei, Seyed H.

Nowadays, the possibility to easy open a food package is of great interest both from the consumer and food producers’ perspective. In this study, the peel/seal properties of poly (ethylene methyl acrylate) (EMA)/polybutene-1 (PB-1) blend films were investigated. Three blends of EMA/PB-1 with different methyl acrylate (MA) content were prepared using cast extrusion process. Differential Scanning Calorimetry (DSC) was used to investigate the thermal behavior as well as the crystalinity of the blends. The effect of polymer matrix on the crystalline structure of PB-1 was studied using Wide Angle X-ray Diffraction (WAXD) and DSC. T-peel tests were carried out onmore » the heat sealed films at various seal temperatures. The effect of MA content and heat seal temperature on peel/seal properties (i.e. peel initiation temperature, temperature window of sealability and peel strength) of the films were studied.« less

From SOLER to SURETY for effective non-verbal communication.

PubMed

Stickley, Theodore

2011-11-01

This paper critiques the model for non-verbal communication referred to as SOLER (which stands for: "Sit squarely"; "Open posture"; "Lean towards the other"; "Eye contact; "Relax"). It has been approximately thirty years since Egan (1975) introduced his acronym SOLER as an aid for teaching and learning about non-verbal communication. There is evidence that the SOLER framework has been widely used in nurse education with little published critical appraisal. A new acronym that might be appropriate for non-verbal communication skills training and education is proposed and this is SURETY (which stands for "Sit at an angle"; "Uncross legs and arms"; "Relax"; "Eye contact"; "Touch"; "Your intuition"). The proposed model advances the SOLER model by including the use of touch and the importance of individual intuition is emphasised. The model encourages student nurse educators to also think about therapeutic space when they teach skills of non-verbal communication. Copyright © 2011 Elsevier Ltd. All rights reserved.

Ultrasensitive sensing with three-dimensional terahertz metamaterial absorber

NASA Astrophysics Data System (ADS)

Tan, Siyu; Yan, Fengping; Wang, Wei; Zhou, Hong; Hou, Yafei

2018-05-01

Planar metasurfaces and metamaterial absorbers have shown great promise for label-free sensing applications at microwaves, optical and terahertz frequencies. The realization of high-quality-factor resonance in these structures is of significant interest to enhance the sensing sensitivities to detect minute frequency shifts. We propose and demonstrate in this manuscript an ultrasensitive terahertz metamaterial absorber sensor based on a three-dimensional split ring resonator absorber with a high quality factor of 60.09. The sensing performance of the proposed absorber sensor was systematically investigated through detailed numerical calculations and a maximum refractive index sensitivity of 34.40% RIU‑1 was obtained. Furthermore, the absorber sensor can maintain a high sensitivity for a wide range of incidence angles up to 60° under TM polarization incidence. These findings would improve the design flexibility of the absorber sensors and further open up new avenues to achieve ultrasensitive sensing in the terahertz regime.

Disorder-induced Room Temperature Ferromagnetism in Glassy Chromites

PubMed Central

Araujo, C. Moyses; Nagar, Sandeep; Ramzan, Muhammad; Shukla, R.; Jayakumar, O. D.; Tyagi, A. K.; Liu, Yi-Sheng; Chen, Jeng-Lung; Glans, Per-Anders; Chang, Chinglin; Blomqvist, Andreas; Lizárraga, Raquel; Holmström, Erik; Belova, Lyubov; Guo, Jinghua; Ahuja, Rajeev; Rao, K. V.

2014-01-01

We report an unusual robust ferromagnetic order above room temperature upon amorphization of perovskite [YCrO3] in pulsed laser deposited thin films. This is contrary to the usual expected formation of a spin glass magnetic state in the resulting disordered structure. To understand the underlying physics of this phenomenon, we combine advanced spectroscopic techniques and first-principles calculations. We find that the observed order-disorder transformation is accompanied by an insulator-metal transition arising from a wide distribution of Cr-O-Cr bond angles and the consequent metallization through free carriers. Similar results also found in YbCrO3-films suggest that the observed phenomenon is more general and should, in principle, apply to a wider range of oxide systems. The ability to tailor ferromagnetic order above room temperature in oxide materials opens up many possibilities for novel technological applications of this counter intuitive effect. PMID:24732685

Analysis of Balance Ability Dependent on the Angle of the Knee Joint in Females in Their 20s

PubMed Central

Yoon, Se-Won; Lee, Jeong-Woo; Cho, Woon-Su; Kim, An-Na; Lee, Kyung-Hee

2013-01-01

The aim of this study was to investigate how balance ability according to angle of the knee joint changes in young female adults wearing a knee orthosis. [Methods] This study was conducted with 11 healthy female adults. The subjects used a knee brace that could be set to angles of 0°, 15°, and 30° of knee flexion. The ability to balance was evaluated by balance assessment. A total of four postures were used for measurements: a forward-facing posture with the eyes open on a stable surface (NO), a forward-facing posture with the eyes closed on a stable surface (NC), a forward-facing posture with the eyes open on an unstable surface (PO), and a forward-facing posture with the eyes closed on an unstable surface (PC). [Results] Regarding the weight distribution index and stability index on a stable surface, there was no interaction according to whether there was visual deprivation or not or according to knee flexion angle. Furthermore, the stability index on an unstable surface showed no interaction according to whether there was visual deprivation or not or according to knee flexion angle. But the WDI on a stable surface showed no interaction according to whether there was visual deprivation or not or according to knee flexion angle. [Conclusion] There were significant differences in the knee extension range of motion of normal elderly people and knee osteoarthritis, and the quadriceps femoris played an important role in knee function in individuals with knee osteoarthritis. PMID:24259902

Symmetric rearrangement of groundwater-fed streams.

PubMed

Yi, Robert; Cohen, Yossi; Devauchelle, Olivier; Gibbins, Goodwin; Seybold, Hansjörg; Rothman, Daniel H

2017-11-01

Streams shape landscapes through headward growth and lateral migration. When these streams are primarily fed by groundwater, recent work suggests that their tips advance to maximize the symmetry of the local Laplacian field associated with groundwater flow. We explore the extent to which such forcing is responsible for the lateral migration of streams by studying two features of groundwater-fed streams in Bristol, Florida: their confluence angle near junctions and their curvature. First, we find that, while streams asymptotically form a 72° angle near their tips, they simultaneously exhibit a wide 120° confluence angle within approximately 10 m of their junctions. We show that this wide angle maximizes the symmetry of the groundwater field near the junction. Second, we argue that streams migrate laterally within valleys and present a new spectral analysis method to relate planform curvature to the surrounding groundwater field. Our results suggest that streams migrate laterally in response to fluxes from the surrounding groundwater table, providing evidence of a new mechanism that complements Laplacian growth at their tips.

A Wide Field of View Plasma Spectrometer

DOE PAGES

Skoug, Ruth M.; Funsten, Herbert O.; Moebius, Eberhard; ...

2016-07-01

Here we present a fundamentally new type of space plasma spectrometer, the wide field of view plasma spectrometer, whose field of view is >1.25π ster using fewer resources than traditional methods. The enabling component is analogous to a pinhole camera with an electrostatic energy-angle filter at the image plane. Particle energy-per-charge is selected with a tunable bias voltage applied to the filter plate relative to the pinhole aperture plate. For a given bias voltage, charged particles from different directions are focused by different angles to different locations. Particles with appropriate locations and angles can transit the filter plate and aremore » measured using a microchannel plate detector with a position-sensitive anode. Full energy and angle coverage are obtained using a single high-voltage power supply, resulting in considerable resource savings and allowing measurements at fast timescales. Lastly, we present laboratory prototype measurements and simulations demonstrating the instrument concept and discuss optimizations of the instrument design for application to space measurements.« less

The effectiveness of early lens extraction with intraocular lens implantation for the treatment of primary angle-closure glaucoma (EAGLE): study protocol for a randomized controlled trial.

PubMed

Azuara-Blanco, Augusto; Burr, Jennifer M; Cochran, Claire; Ramsay, Craig; Vale, Luke; Foster, Paul; Friedman, David; Quayyum, Zahidul; Lai, Jimmy; Nolan, Winnie; Aung, Tin; Chew, Paul; McPherson, Gladys; McDonald, Alison; Norrie, John

2011-05-23

Glaucoma is the leading cause of irreversible blindness. Although primary open-angle glaucoma is more common, primary angle-closure glaucoma (PACG) is more likely to result in irreversible blindness. By 2020, 5·3 million people worldwide will be blind because of PACG. The current standard care for PACG is a stepped approach of a combination of laser iridotomy surgery (to open the drainage angle) and medical treatment (to reduce intraocular pressure). If these treatments fail, glaucoma surgery (eg, trabeculectomy) is indicated. It has been proposed that, because the lens of the eye plays a major role in the mechanisms leading to PACG, early clear lens extraction will improve glaucoma control by opening the drainage angle. This procedure might reduce the need for drugs and glaucoma surgery, maintain good visual acuity, and improve quality of life compared with standard care.EAGLE aims to evaluate whether early lens extraction improves patient-reported, clinical outcomes, and cost-effectiveness, compared with standard care. EAGLE is a multicentre pragmatic randomized trial. All people presenting to the recruitment centres in the UK and east Asia with newly diagnosed PACG and who are at least 50 years old are eligible.The primary outcomes are EQ-5D, intraocular pressure, and incremental cost per quality adjusted life year (QALY) gained. Other outcomes are: vision and glaucoma-specific patient-reported outcomes, visual acuity, visual field, angle closure, number of medications, additional surgery (e.g., trabeculectomy), costs to the health services and patients, and adverse events.A single main analysis will be done at the end of the trial, after three years of follow-up. The analysis will be based on all participants as randomized (intention to treat). 400 participants (200 in each group) will be recruited, to have 90% power at 5% significance level to detect a difference in EQ-5D score between the two groups of 0·05, and a mean difference in intraocular pressure of 1·75 mm Hg. The study will have 80% power to detect a difference of 15% in the glaucoma surgery rate. ISRCTN44464607.

Wide angle view of Mission Control Center during Apollo 14 transmission

NASA Image and Video Library

1971-01-31

S71-17122 (31 Jan. 1971) --- A wide angle overall view of the Mission Operations Control Room (MOCR) in the Mission Control Center at the Manned spacecraft Center. This view was photographed during the first color television transmission from the Apollo 14 Command Module. Projected on the large screen at the right front of the MOCR is a view of the Apollo 14 Lunar Module, still attached to the Saturn IVB stage. The Command and Service Modules were approaching the LM/S-IVB during transposition and docking maneuvers.

ELECTROMAGNETIC SCATTERING AND ANTENNA TECHNOLOGY (EMSAT) Task Order 0003: Design of a Circularly Polarized, 20 60 GHZ Active Phased Array for Wide Angle Scanning

DTIC Science & Technology

2017-08-08

Another area of the design that needs to be experimentally tested is the SMPS connectors used to attach the two beamforming stages together. In...AFRL-RY-WP-TR-2017-0104 ELECTROMAGNETIC SCATTERING AND ANTENNA TECHNOLOGY (EMSAT) Task Order 0003: Design of a Circularly Polarized, 20-60...Order 0003: Design of a Circularly Polarized, 20-60 GHZ Active Phased Array for Wide Angle Scanning 5a. CONTRACT NUMBER FA8650-14-D-1714-0003 5b

Wide-angle X-ray scattering study of heat-treated PEEK and PEEK composite

NASA Technical Reports Server (NTRS)

Cebe, Peggy; Lowry, Lynn; Chung, Shirley Y.; Yavrouian, Andre; Gupta, Amitava

1987-01-01

Samples of poly(etheretherketone) (PEEK) neat resin and APC-2 carbon fiber composite were subjected to various heat treatments, and the effect of quenching and annealing treatments was studied by wide-angle X-ray scattering. It is found that high-temperature treatments may introduce disorder into neat resin and composite PEEK when followed by rapid cooling. The disorder is metastable and can revert to ordered state when the material is heated above its glass transition temperature and then cooled slowly. The disorder may result from residual thermal stresses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Sucheng; Duan, Qian; Li, Shuo

We experimentally demonstrate that perfect electromagnetic absorption can be realized in the one-atom thick graphene. Employing coherent illumination in the waveguide system, the absorbance of the unpatterned graphene monolayer is observed to be greater than 94% over the microwave X-band, 7–13 GHz, and to achieve a full absorption, >99% in experiment, at ∼8.3 GHz. In addition, the absorption characteristic manifests equivalently a wide range of incident angle. The experimental results agree very well with the theoretical calculations. Our work accomplishes the broadband, wide-angle, high-performance absorption in the thinnest material with simple configuration.

Evaluation of a novel collimator for molecular breast tomosynthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilland, David R.; Welch, Benjamin L.; Lee, Seungjoon

Here, this study investigated a novel gamma camera for molecular breast tomosynthesis (MBT), which is a nuclear breast imaging method that uses limited angle tomography. The camera is equipped with a variable angle, slant-hole (VASH) collimator that allows the camera to remain close to the breast throughout the acquisition. The goal of this study was to evaluate the spatial resolution and count sensitivity of this camera and to compare contrast and contrast-to-noise ratio (CNR) with conventional planar imaging using an experimental breast phantom. Methods The VASH collimator mounts to a commercial gamma camera for breast imaging that uses a pixelatedmore » (3.2 mm), 15 × 20 cm NaI crystal. Spatial resolution was measured in planar images over a range of distances from the collimator (30-100 mm) and a range of slant angles (–25° to 25°) using 99mTc line sources. Spatial resolution was also measured in reconstructed MBT images including in the depth dimension. The images were reconstructed from data acquired over the -25° to 25° angular range using an iterative algorithm adapted to the slant-hole geometry. Sensitivity was measured over the range of slant angles using a disk source. Measured spatial resolution and sensitivity were compared to theoretical values. Contrast and CNR were measured using a breast phantom containing spherical lesions (6.2 mm and 7.8 mm diameter) and positioned over a range of depths in the phantom. The MBT and planar methods had equal scan time, and the count density in the breast phantom data was similar to that in clinical nuclear breast imaging. The MBT method used an iterative reconstruction algorithm combined with a postreconstruction Metz filter. Results The measured spatial resolution in planar images agreed well with theoretical calculations over the range of distances and slant angles. The measured FWHM was 9.7 mm at 50 mm distance. In reconstructed MBT images, the spatial resolution in the depth dimension was approximately 2.2 mm greater than the other two dimensions due to the limited angle data. The measured count sensitivity agreed closely with theory over all slant angles when using a wide energy window. At 0° slant angle, measured sensitivity was 19.7 counts sec -1 μCi -1 with the open energy window and 11.2 counts sec -1 μCi -1 with a 20% wide photopeak window (126 to 154 keV). The measured CNR in the MBT images was significantly greater than in the planar images for all but the lowest CNR cases where the lesion detectability was extremely low for both MBT and planar. The 7.8 mm lesion at 37 mm depth was marginally detectable in the planar image but easily visible in the MBT image. The improved CNR with MBT was due to a large improvement in contrast, which out-weighed the increase in image noise. Conclusion The spatial resolution and count sensitivity measurements with the prototype MBT system matched theoretical calculations, and the measured CNR in breast phantom images was generally greater with the MBT system compared to conventional planar imaging. These results demonstrate the potential of the proposed MBT system to improve lesion detection in nuclear breast imaging.« less

Evaluation of a novel collimator for molecular breast tomosynthesis.

PubMed

Gilland, David R; Welch, Benjamin L; Lee, Seungjoon; Kross, Brian; Weisenberger, Andrew G

2017-11-01

This study investigated a novel gamma camera for molecular breast tomosynthesis (MBT), which is a nuclear breast imaging method that uses limited angle tomography. The camera is equipped with a variable angle, slant-hole (VASH) collimator that allows the camera to remain close to the breast throughout the acquisition. The goal of this study was to evaluate the spatial resolution and count sensitivity of this camera and to compare contrast and contrast-to-noise ratio (CNR) with conventional planar imaging using an experimental breast phantom. The VASH collimator mounts to a commercial gamma camera for breast imaging that uses a pixelated (3.2 mm), 15 × 20 cm NaI crystal. Spatial resolution was measured in planar images over a range of distances from the collimator (30-100 mm) and a range of slant angles (-25° to 25°) using 99m Tc line sources. Spatial resolution was also measured in reconstructed MBT images including in the depth dimension. The images were reconstructed from data acquired over the -25° to 25° angular range using an iterative algorithm adapted to the slant-hole geometry. Sensitivity was measured over the range of slant angles using a disk source. Measured spatial resolution and sensitivity were compared to theoretical values. Contrast and CNR were measured using a breast phantom containing spherical lesions (6.2 mm and 7.8 mm diameter) and positioned over a range of depths in the phantom. The MBT and planar methods had equal scan time, and the count density in the breast phantom data was similar to that in clinical nuclear breast imaging. The MBT method used an iterative reconstruction algorithm combined with a postreconstruction Metz filter. The measured spatial resolution in planar images agreed well with theoretical calculations over the range of distances and slant angles. The measured FWHM was 9.7 mm at 50 mm distance. In reconstructed MBT images, the spatial resolution in the depth dimension was approximately 2.2 mm greater than the other two dimensions due to the limited angle data. The measured count sensitivity agreed closely with theory over all slant angles when using a wide energy window. At 0° slant angle, measured sensitivity was 19.7 counts sec -1 μCi -1 with the open energy window and 11.2 counts sec -1 μCi -1 with a 20% wide photopeak window (126 to 154 keV). The measured CNR in the MBT images was significantly greater than in the planar images for all but the lowest CNR cases where the lesion detectability was extremely low for both MBT and planar. The 7.8 mm lesion at 37 mm depth was marginally detectable in the planar image but easily visible in the MBT image. The improved CNR with MBT was due to a large improvement in contrast, which out-weighed the increase in image noise. The spatial resolution and count sensitivity measurements with the prototype MBT system matched theoretical calculations, and the measured CNR in breast phantom images was generally greater with the MBT system compared to conventional planar imaging. These results demonstrate the potential of the proposed MBT system to improve lesion detection in nuclear breast imaging. © 2017 American Association of Physicists in Medicine.

Evaluation of a novel collimator for molecular breast tomosynthesis

DOE PAGES

Gilland, David R.; Welch, Benjamin L.; Lee, Seungjoon; ...

2017-09-06

Here, this study investigated a novel gamma camera for molecular breast tomosynthesis (MBT), which is a nuclear breast imaging method that uses limited angle tomography. The camera is equipped with a variable angle, slant-hole (VASH) collimator that allows the camera to remain close to the breast throughout the acquisition. The goal of this study was to evaluate the spatial resolution and count sensitivity of this camera and to compare contrast and contrast-to-noise ratio (CNR) with conventional planar imaging using an experimental breast phantom. Methods The VASH collimator mounts to a commercial gamma camera for breast imaging that uses a pixelatedmore » (3.2 mm), 15 × 20 cm NaI crystal. Spatial resolution was measured in planar images over a range of distances from the collimator (30-100 mm) and a range of slant angles (–25° to 25°) using 99mTc line sources. Spatial resolution was also measured in reconstructed MBT images including in the depth dimension. The images were reconstructed from data acquired over the -25° to 25° angular range using an iterative algorithm adapted to the slant-hole geometry. Sensitivity was measured over the range of slant angles using a disk source. Measured spatial resolution and sensitivity were compared to theoretical values. Contrast and CNR were measured using a breast phantom containing spherical lesions (6.2 mm and 7.8 mm diameter) and positioned over a range of depths in the phantom. The MBT and planar methods had equal scan time, and the count density in the breast phantom data was similar to that in clinical nuclear breast imaging. The MBT method used an iterative reconstruction algorithm combined with a postreconstruction Metz filter. Results The measured spatial resolution in planar images agreed well with theoretical calculations over the range of distances and slant angles. The measured FWHM was 9.7 mm at 50 mm distance. In reconstructed MBT images, the spatial resolution in the depth dimension was approximately 2.2 mm greater than the other two dimensions due to the limited angle data. The measured count sensitivity agreed closely with theory over all slant angles when using a wide energy window. At 0° slant angle, measured sensitivity was 19.7 counts sec -1 μCi -1 with the open energy window and 11.2 counts sec -1 μCi -1 with a 20% wide photopeak window (126 to 154 keV). The measured CNR in the MBT images was significantly greater than in the planar images for all but the lowest CNR cases where the lesion detectability was extremely low for both MBT and planar. The 7.8 mm lesion at 37 mm depth was marginally detectable in the planar image but easily visible in the MBT image. The improved CNR with MBT was due to a large improvement in contrast, which out-weighed the increase in image noise. Conclusion The spatial resolution and count sensitivity measurements with the prototype MBT system matched theoretical calculations, and the measured CNR in breast phantom images was generally greater with the MBT system compared to conventional planar imaging. These results demonstrate the potential of the proposed MBT system to improve lesion detection in nuclear breast imaging.« less

System description and analysis. Part 1: Feasibility study for helicopter/VTOL wide-angle simulation image generation display system

NASA Technical Reports Server (NTRS)

1977-01-01

A preliminary design for a helicopter/VSTOL wide angle simulator image generation display system is studied. The visual system is to become part of a simulator capability to support Army aviation systems research and development within the near term. As required for the Army to simulate a wide range of aircraft characteristics, versatility and ease of changing cockpit configurations were primary considerations of the study. Due to the Army's interest in low altitude flight and descents into and landing in constrained areas, particular emphasis is given to wide field of view, resolution, brightness, contrast, and color. The visual display study includes a preliminary design, demonstrated feasibility of advanced concepts, and a plan for subsequent detail design and development. Analysis and tradeoff considerations for various visual system elements are outlined and discussed.

Evaluation of anterior chamber angle under dark and light conditions in angle closure glaucoma: An anterior segment OCT study.

PubMed

Masoodi, Habibeh; Jafarzadehpur, Ebrahim; Esmaeili, Alireza; Abolbashari, Fereshteh; Ahmadi Hosseini, Seyed Mahdi

2014-08-01

To evaluate changes of nasal and temporal anterior chamber angle (ACA) in subjects with angle closure glaucoma using Spectralis AS-OCT (SAS-OCT) under dark and light conditions. Based on dark-room gonioscopy, 24 subjects with open angles and 86 with narrow angles participated in this study. The nasal and temporal angle opening distance at 500 μm anterior to the scleral spur (AOD500), nasal and temporal ACA were measured using SAS-OCT in light and dark conditions. In 2 groups, ACA and AOD500 in nasal and temporal quadrants were significantly greater in light compared to dark (all with p=0.000). The AOD500 and ACA were significantly higher in nasal than temporal in measured conditions for 2 groups except the ACA and AOD500 of normal group measured in light. The difference between nasal and temporal in dark (29.07 ± 65.71 μm for AOD500 and 5.7 ± 4.07° for ACA) was greater than light (24.86 ± 79.85 μm for AOD500 and 2.09 ± 7.21° for ACA) condition. But the difference was only significant for ACA (p=0.000). The correlation analysis showed a negative correlation between AOD500 and pupil diameter in temporal and nasal quadrants (both with p=0.000). While temporal AOD500 difference correlated with spherical equivalent, temporal and asal gonioscopy, nasal AOD correlated with IOP, temporal and nasal gonioscopy. Clinically important changes in ACA structure could be detected with SAS-OCT in nasal and temporal quadrants under different illumination intensity. The results could help in improvement of examination condition for better and more accurate assessment of individuals with angle closure glaucoma. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

MO-F-CAMPUS-T-01: Radiosurgery of Multiple Brain Metastases with Single-Isocenter VMAT: Optimizing Treatment Geometry to Reduce Normal Brain Dose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Q; Snyder, K; Liu, C

Purpose: To develop an optimization algorithm to reduce normal brain dose by optimizing couch and collimator angles for single isocenter multiple targets treatment of stereotactic radiosurgery. Methods: Three metastatic brain lesions were retrospectively planned using single-isocenter volumetric modulated arc therapy (VMAT). Three matrices were developed to calculate the projection of each lesion on Beam’s Eye View (BEV) by the rotating couch, collimator and gantry respectively. The island blocking problem was addressed by computing the total area of open space between any two lesions with shared MLC leaf pairs. The couch and collimator angles resulting in the smallest open areas weremore » the optimized angles for each treatment arc. Two treatment plans with and without couch and collimator angle optimization were developed using the same objective functions and to achieve 99% of each target volume receiving full prescription dose of 18Gy. Plan quality was evaluated by calculating each target’s Conformity Index (CI), Gradient Index (GI), and Homogeneity index (HI), and absolute volume of normal brain V8Gy, V10Gy, V12Gy, and V14Gy. Results: Using the new couch/collimator optimization strategy, dose to normal brain tissue was reduced substantially. V8, V10, V12, and V14 decreased by 2.3%, 3.6%, 3.5%, and 6%, respectively. There were no significant differences in the conformity index, gradient index, and homogeneity index between two treatment plans with and without the new optimization algorithm. Conclusion: We have developed a solution to the island blocking problem in delivering radiation to multiple brain metastases with shared isocenter. Significant reduction in dose to normal brain was achieved by using optimal couch and collimator angles that minimize total area of open space between any of the two lesions with shared MLC leaf pairs. This technique has been integrated into Eclipse treatment system using scripting API.« less

The influence of third molars in the line of mandibular angle fractures on wound and bone healing.

PubMed

Ulbrich, N; Ettl, T; Waiss, W; Gosau, M; Moralis, A; Reichert, T E; Mueller, S

2016-07-01

The objective of this study was to evaluate postoperative complications after removal or retention of the third molar in the line of mandibular angle fractures. This retrospective study included the data of 98 patients with a molar in the line of a mandibular angle fracture treated with internal reduction and mini-plate fixation at our department over 9 years. Patients were classified into two groups: tooth removal during osteosynthesis (n = 45) and tooth retention (n = 55). The primary target criterion was the incidence of minor (outpatient treatment, local measures) and major (surgical revision, rehospitalisation) complications. Time between trauma and surgery was 1.4 days (range 0 to 12), and the average follow-up 291 days (range 66 to 863). Regarding the eruption status, 26 of 52 (50.0 %) impacted third molars, 11 of 19 (57.9 %) incompletely erupted and 8 of 27 (29.6 %) completely erupted molars had been removed during open reduction. Overall, 17 (17.3 %) patients had postoperative minor (n = 7) or major (n = 10) complications, in detail 10/45 (22.0 %) patients after tooth removal and 7/55 (13 %) patients after tooth retention (p = 0.286). Complication rates between impacted and incompletely erupted third molars (impacted molars 15.0 %, incompletely erupted molars 10.0 %) did not differ significantly, but completely erupted molars had a complication rate of 26.0 %. Mandibular angle fractures with a completely erupted third molar show the highest complication rate after open reduction and osteosynthesis. Retention of a non-infectious third molar facilitates open reduction and does not increase the complication risk. The study helps with the decision of removing or retention of a third molar during surgical treatment of a mandibular angle fracture.

Evaluation and comparison of indentation ultrasound biomicroscopy gonioscopy in relative pupillary block, peripheral anterior synechia, and plateau iris configuration.

PubMed

Matsunaga, Koichi; Ito, Kunio; Esaki, Koji; Sugimoto, Kota; Sano, Toru; Miura, Katsuya; Sasoh, Mikio; Uji, Yukitaka

2004-12-01

To evaluate and compare the findings and changes of the anterior chamber angle configuration with indentation ultrasound biomicroscopy (UBM) gonioscopy in relative pupillary block (RPB), peripheral anterior synechia (PAS), and plateau iris configuration (PIC). This study included 73 eyes of 52 patients with RPB (n = 26), PAS (n = 21), or PIC (n = 26). First, a conventional UBM scan was performed using a normal size standard eye cup before indentation. Then, for indentation UBM gonioscopy, scans were performed using a new eye cup that we designed. For evaluation of the angle, angle opening distance 500 and angle recess area were recorded and evaluated with regard to the effect of expansion on the anterior chamber angle. Indentation UBM gonioscopy showed the characteristic images in each of the eyes. The angle of all examined eyes was significantly widened with indentation (P < 0.01). The angle changes in eyes with RPB were significantly greater than in eyes with PAS or PIC (P < 0.01). Indentation UBM gonioscopy is a very useful method for observing the angle and diagnosis of RPB, PAS, and PIC.

Solar System Portrait - 60 Frame Mosaic

NASA Image and Video Library

1996-09-13

The cameras of Voyager 1 on Feb. 14, 1990, pointed back toward the sun and took a series of pictures of the sun and the planets, making the first ever portrait of our solar system as seen from the outside. In the course of taking this mosaic consisting of a total of 60 frames, Voyager 1 made several images of the inner solar system from a distance of approximately 4 billion miles and about 32 degrees above the ecliptic plane. Thirty-nine wide angle frames link together six of the planets of our solar system in this mosaic. Outermost Neptune is 30 times further from the sun than Earth. Our sun is seen as the bright object in the center of the circle of frames. The wide-angle image of the sun was taken with the camera's darkest filter (a methane absorption band) and the shortest possible exposure (5 thousandths of a second) to avoid saturating the camera's vidicon tube with scattered sunlight. The sun is not large as seen from Voyager, only about one-fortieth of the diameter as seen from Earth, but is still almost 8 million times brighter than the brightest star in Earth's sky, Sirius. The result of this great brightness is an image with multiple reflections from the optics in the camera. Wide-angle images surrounding the sun also show many artifacts attributable to scattered light in the optics. These were taken through the clear filter with one second exposures. The insets show the planets magnified many times. Narrow-angle images of Earth, Venus, Jupiter, Saturn, Uranus and Neptune were acquired as the spacecraft built the wide-angle mosaic. Jupiter is larger than a narrow-angle pixel and is clearly resolved, as is Saturn with its rings. Uranus and Neptune appear larger than they really are because of image smear due to spacecraft motion during the long (15 second) exposures. From Voyager's great distance Earth and Venus are mere points of light, less than the size of a picture element even in the narrow-angle camera. Earth was a crescent only 0.12 pixel in size. Coincidentally, Earth lies right in the center of one of the scattered light rays resulting from taking the image so close to the sun. http://photojournal.jpl.nasa.gov/catalog/PIA00451

Solar System Portrait - 60 Frame Mosaic

NASA Technical Reports Server (NTRS)

1990-01-01

The cameras of Voyager 1 on Feb. 14, 1990, pointed back toward the sun and took a series of pictures of the sun and the planets, making the first ever 'portrait' of our solar system as seen from the outside. In the course of taking this mosaic consisting of a total of 60 frames, Voyager 1 made several images of the inner solar system from a distance of approximately 4 billion miles and about 32 degrees above the ecliptic plane. Thirty-nine wide angle frames link together six of the planets of our solar system in this mosaic. Outermost Neptune is 30 times further from the sun than Earth. Our sun is seen as the bright object in the center of the circle of frames. The wide-angle image of the sun was taken with the camera's darkest filter (a methane absorption band) and the shortest possible exposure (5 thousandths of a second) to avoid saturating the camera's vidicon tube with scattered sunlight. The sun is not large as seen from Voyager, only about one-fortieth of the diameter as seen from Earth, but is still almost 8 million times brighter than the brightest star in Earth's sky, Sirius. The result of this great brightness is an image with multiple reflections from the optics in the camera. Wide-angle images surrounding the sun also show many artifacts attributable to scattered light in the optics. These were taken through the clear filter with one second exposures. The insets show the planets magnified many times. Narrow-angle images of Earth, Venus, Jupiter, Saturn, Uranus and Neptune were acquired as the spacecraft built the wide-angle mosaic. Jupiter is larger than a narrow-angle pixel and is clearly resolved, as is Saturn with its rings. Uranus and Neptune appear larger than they really are because of image smear due to spacecraft motion during the long (15 second) exposures. From Voyager's great distance Earth and Venus are mere points of light, less than the size of a picture element even in the narrow-angle camera. Earth was a crescent only 0.12 pixel in size. Coincidentally, Earth lies right in the center of one of the scattered light rays resulting from taking the image so close to the sun.

A comparative study on omnidirectional anti-reflection SiO2 nanostructure films coating by glancing angle deposition

NASA Astrophysics Data System (ADS)

Prachachet, R.; Samransuksamer, B.; Horprathum, M.; Eiamchai, P.; Limwichean, S.; Chananonnawathorn, C.; Lertvanithphol, T.; Muthitamongkol, P.; Boonruang, S.; Buranasiri, P.

2018-02-01

Fabricated omnidirectional anti-reflection nanostructure films as a one of the promising alternative solar cell applications have attracted enormous scientific and industrial research benefits to their broadband, effective over a wide range of incident angles, lithography-free and high-throughput process. Recently, the nanostructure SiO2 film was the most inclusive study on anti-reflection with omnidirectional and broadband characteristics. In this work, the three-dimensional silicon dioxide (SiO2) nanostructured thin film with different morphologies including vertical align, slant, spiral and thin films were fabricated by electron beam evaporation with glancing angle deposition (GLAD) on the glass slide and silicon wafer substrate. The morphological of the prepared samples were characterized by field-emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HRTEM). The transmission, omnidirectional and birefringence property of the nanostructure SiO2 films were investigated by UV-Vis-NIR spectrophotometer and variable angle spectroscopic ellipsometer (VASE). The spectrophotometer measurement was performed at normal incident angle and a full spectral range of 200 - 2000 nm. The angle dependent transmission measurements were investigated by rotating the specimen, with incidence angle defined relative to the surface normal of the prepared samples. This study demonstrates that the obtained SiO2 nanostructure film coated on glass slide substrate exhibits a higher transmission was 93% at normal incident angle. In addition, transmission measurement in visible wavelength and wide incident angles -80 to 80 were increased in comparison with the SiO2 thin film and glass slide substrate due to the transition in the refractive index profile from air to the nanostructure layer that improve the antireflection characteristics. The results clearly showed the enhanced omnidirectional and broadband characteristic of the three dimensional SiO2 nanostructure film coating.

Mixed-phase aerosol particles

NASA Astrophysics Data System (ADS)

Corti, T.; Krieger, U. K.; Koop, T.; Peter, T.

2003-04-01

Within a liquid aerosol particle a solid phase may coexist with the liquid over a wide range of ambient conditions. The optical properties of such particles are of interest for a number of reasons. They will affect the scattering albedo of atmospheric aerosols, may cause depolarisation in lidar measurements, and potentially open a window for studying the internal morphology and physical properties (e.g. wetting properties, diffusion constants) of composite particles in laboratory experiments. In this contribution, we will present results of experimental and theoretical work on mixed-phase aerosol particles. The optical properties of mixed-phase particles depend on the location of the inclusion in the liquid phase, which is determined by the surface tensions of the involved interfaces. In the case of complete wetting, the energetically favoured position of the inclusion is in the volume of the liquid phase. For partial wetting, a position at the surface of the liquid phase is favoured, with the contact angle between the solid, liquid and air being described by Young's equation. For systems with small contact angles, the difference in energy between an inclusion situated at the droplets surface and in its volume may be so small that the thermal energy kT is sufficient to displace the inclusion from the droplet surface into its volume. The critical contact angle depends on the size of the inclusion and the droplet and ranges from 0.1 to 10 degrees. Examples of mixed-phase aerosol particles are aged soot particles and sea salt particles at low relative humidity. For aged soot, contact angles on sulphuric acid clearly above 10 degrees have been reported, so that soot inclusions are expected to be located at the surface of aerosol particles. For mixed-phase sea salt particles, consisting of a solid NaCl inclusion and an aqueous solution of mainly NaCl and MgCl2, our measurements on macroscopic NaCl crystals show a contact angle clearly below 10 degrees and possibly as low as 0.1 degrees. An experimental method - based on measuring photon count statistics - is developed to distinguish in single levitated aerosol particle whether a solid inclusion is located in the volume of the particle or at its surface.

Influence of guide vane opening on the flow phenomena in a pump turbine during a fast transition from pump mode to generating mode

NASA Astrophysics Data System (ADS)

Stens, C.; Riedelbauch, S.

2017-04-01

Due to a more fluctuating energy production caused by renewable energies such as wind and solar power, the number of changes between operating points in pumped storage power plants has increased over the last years. To further increase available regulating power, it is desirable to speed up these changes of operation conditions in Hydro units. Previous studies showed that CFD is well capable of predicting the flow phenomena in the machine under unsteady conditions for a large guide vane opening angle. The present paper investigates the benefits of nearly closed guide vanes during the transition. Results are compared between the two different angles as well as between simulation and measurement.

Nonimaging Optical Illumination System

DOEpatents

Winston, Roland

1994-02-22

A nonimaging illumination or concentration optical device. An optical device is provided having a light source, a light reflecting surface with an opening and positioned partially around the light source which is opposite the opening of the light reflecting surface. The light reflecting surface is disposed to produce a substantially uniform intensity output with the reflecting surface defined in terms of a radius vector R.sub.i in conjunction with an angle .phi..sub.i between R.sub.i, a direction from the source and an angle .theta..sub.i between direct forward illumination and the light ray reflected once from the reflecting surface. R.sub.i varies as the exponential of tan (.phi..sub.i -.theta..sub.i)/2 integrated over .phi..sub.i.

Effectiveness Using Circular Fibre Steel Flap Gate As a Control Structure Towards the Hydraulic Characteristics in Open Channel

NASA Astrophysics Data System (ADS)

Adib, M. R. M.; Amirza, A. R. M.; Wardah, T.; Junaidah, A.

2016-07-01

Hydraulic control gate structure plays an important role in regulating the flow of water in river, canal or water reservoir. One of the most appropriate structures in term of resolving the problem of flood occured is the construction of circular fibre steel flap gate. Therefore, an experiment has been conducted by using an open channel model at laboratory. In this case, hydraulic jump and backwater were the method to determined the hydraulic characteristics of circular fibre steel flap gate in an open channel model. From the experiment, the opening angle of flap gate can receive discharges with the highest flow rate of 0.035 m3/s with opening angle was 47°. The type of jump that occurs at the slope of 1/200 for a distance of 5.0 m is a standing jump or undulating wave. The height of the backwater can be identified based on the differences of specific force which is specific force before jump, F1 and specific force after jump, F2 from the formation of backwater. Based on the research conducted, the tendency of incident backwater wave occurred was high in every distance of water control location from water inlet is flap slope and the slope of 1/300 which is 0.84 m/s and 0.75 m/s of celerity in open channel model.

3D model of fault and fissures structure of the Kovdor Baddeleyite-Apatite-Magnetite Deposit (NE of the Fennoscandian Shield)

NASA Astrophysics Data System (ADS)

Zhirov, Dmitry; Klimov, Sergey

2015-04-01

The Kovdor baddeleyite-apatite-magnetite deposit (KBAMD) is represented by a large vertical ore body and is located in the southwestern part of the Kovdor ultramafic-alkaline central-type intrusion. The intrusion represents a concentrically zoned complex of rocks with an oval shape in plan, and straight zoning, which complies with the injection and displacement of each of further magma phases from the center towards the periphery. The operation of the deposit in open pits started in 1962, and nowadays, it has produced over 500,000,000 tons of ore. This is one of the largest open pits in the Kola region, which is ca. 2 km long, 1.8 km wide, and over 400 m deep. Regular structural studies has been carried out since late 1970. A unique massif of spatial data has been accumulated so far to include over 25,000 measurements of fissures and faults from the surface, ca. 20,000 measurements of fissures in the oriented drill core (over 18 km) etc. Using this data base the 3D model of fault and fissures structure was designed. The analysis of one has resulted in the identification of a series of laws and features, which are necessary to be taken into account when designing a deep open pit and mining is carried out. These are mainly aspects concerning the origin, kinematics, mechanics and ratio of spatial extension of various fault systems, variation of their parameters at deep horizons, features of a modern stress field in the country rocks, etc. The 3D model has allowed to divide the whole fracture / fissure systems of the massif rocks into 2 large groups: prototectonic system of joints, including cracks of 'liquid magmatic (carbonatite stage) contraction genesis', and newly formed faults due to the superimposed tectonic stages. With regard to the deposit scale, these are characterized as intraformational and transformational, respectively. Each group shows a set (an assemblage) of fault systems with unique features and signs, as well as regular interconnections. The prototectonic assemblage of fissures includes the following main systems: 2-3 subsystems Rd of radial with angle of dip within 65-90° (median at 78°), two subsystems S of a circular subvertical (tangential, crossing Rd) with angle of dip within 60-90° (74°), and two diagonal-conic ones: a centriclinal C dipping towards the center of the intrusion at angles of 25-55° (43°), and a periclinal P dipping from the center of the intrusion at angles of 5-35° (18°). The system of subhorizontal joints L (angle of dip within 0-12°) at deep horizons is insignificantly manifested. All the prototectonic systems are regularly interrelated, and vary asymuthal features according to the law of axial symmetry (when moving around the vertical axis of symmetry passed through the geometric center of the carbonatite intrusion). The superimposed tectonics of post-ore stages forms a few large faults and systems of rupture discontinuities. A few (up to 3) variously oriented displacements are documented in the field on kinematic features (slide furrows, oriented cleavages). They were used for reconstruction of stresses and tectonic evolution. The superimposed tectonic faulting has heterogeneous (local) distribution in the rocks of the deposit, and slight predictability of main parameters. This study was supported by the Russian Scientific Fund (project nos. 14-17-00751).

Factors influencing the effective spray cone angle of pressure-swirl atomizers

NASA Astrophysics Data System (ADS)

Chen, S. K.; Lefebvre, A. H.; Rollbuhler, J.

1992-01-01

The spray cone angles produced by several simplex pressure-swirl nozzles are examined using three liquids whose viscosities range from 0.001 to 0.012 kg/ms (1 to 12 cp). Measurements of both the visible spray cone angle and the effective spray cone angle are carried out over wide ranges of injection pressure and for five different values of the discharge orifice length/diameter ratio. The influence of the number of swirl chamber feed slots on spray cone angle is also examined. The results show that the spray cone angle widens with increase in injection pressure but is reduced by increases in liquid viscosity and/or discharge orifice length/diameter ratio. Variation in the number of swirl chamber feed slots between one and three has little effect on the effective spray cone angle.

Nanospheres with a smectic hydrophobic core and an amorphous PEG hydrophilic shell: structural changes and implications for drug delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murthy, N. Sanjeeva; Zhang, Zheng; Borsadia, Siddharth

The structural changes in nanospheres with a crystalline core and an amorphous diffuse shell were investigated by small-angle neutron scattering (SANS), small-, medium-, and wide-angle X-ray scattering (SAXS, MAXS and WAXS), and differential scanning calorimetry (DSC).

Effects of wind velocity and slope on flame properties

Treesearch

David R. Weise; Gregory S. Biging

1996-01-01

Abstract: The combined effects of wind velocity and percent slope on flame length and angle were measured in an open-topped, tilting wind tunnel by burning fuel beds composed of vertical birch sticks and aspen excelsior. Mean flame length ranged from 0.08 to 1.69 m; 0.25 m was the maximum observed flame length for most backing fires. Flame angle ranged from -46o to 50o...

Signature of non-isotropic distribution of stellar rotation inclination angles in the Praesepe cluster

NASA Astrophysics Data System (ADS)

Kovacs, Geza

2018-04-01

The distribution of the stellar rotation axes of 113 main sequence stars in the open cluster Praesepe are examined by using current photometric rotation periods, spectroscopic rotation velocities, and estimated stellar radii. Three different samples of stellar rotation data on spotted stars from the Galactic field and two independent samples of planetary hosts are used as control samples to support the consistency of the analysis. Considering the high completeness of the Praesepe sample and the behavior of the control samples, we find that the main sequence F - K stars in this cluster are susceptible to rotational axis alignment. Using a cone model, the most likely inclination angle is 76° ± 14° with a half opening angle of 47° ± 24°. Non-isotropic distribution of the inclination angles is preferred over the isotropic distribution, except if the rotation velocities used in this work are systematically overestimated. We found no indication of this being the case on the basis of the currently available data. Data are only available at the CDS, together with the other two compiled datasets used in this paper, via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/L2

Bone morphotypes of the varus and valgus knee.

PubMed

Thienpont, E; Schwab, P E; Cornu, O; Bellemans, J; Victor, J

2017-03-01

Coronal deformity correction with total knee arthroplasty (TKA) is an important feature in the treatment of osteoarthritis (OA). The hypothesis of this study was that bone morphology would be different in varus and valgus deformity, both before osteoarthritis development as well as during and after the disease process of OA. Retrospective study with measurements on preoperative and postoperative full leg standing radiographs of 96 patients who underwent TKA. The included patients were selected for this study because they had an OA knee on one side and a non-arthritic knee on the contralateral side presenting the same type of alignment as the to-be-operated knee (varus or valgus alignment on both sides). The control group of 46 subjects was a group of patients with neutral mechanical alignment who presented for ligamentous problems. A single observer measured mechanical alignment, anatomical alignment, anatomical-mechanical femoral angle and intra-articular bone morphology parameters with an accuracy of 1°. Varus OA group has less distal femoral valgus (mLDFA 89°) than control group (87°) and valgus OA group (mLDFA 85°). Varus OA group has same varus obliquity as control group (MPTA 87°) but more than valgus OA group (MPTA 90°). Joint Line Congruency Angle (JLCA) is 3°open on lateral side in varus and medially open in valgus OA group (2°). The non-arthritic valgus group presents a constitutional mechanical valgus of 184° Hip-Knee-Ankle (HKA) angle. Varus deformity in OA as measured with an HKA angle (HKA) <177° is a combination of distal femoral wear, tibial varus obliquity and lateral joint line opening. Valgus deformity in OA with an HKA > 183° is a combination of femoral distal joint line obliquity and wear combined with medial opening due to medial collateral ligament stretching. The clinical importance of bone morphotype analysis is that it shows the intra-articular potential of alignment correction when mechanical axis cuts are performed. Bone morphology in varus and valgus deformity is different before and after osteoarthritis. Perpendicular cuts to mechanical axes do not necessarily lead to neutral mechanical axis. Constitutional mechanical valgus was observed as 184° HKA angle before the development of OA. Level IV study.

Relationship Between Anterior Lamina Cribrosa Surface Tilt and Glaucoma Development in Myopic Eyes.

PubMed

Lee, Eun Jung; Han, Jong Chul; Kee, Changwon

2017-05-01

To evaluate the anterior lamina cribrosa (LC) surface tilt angle in myopic eyes and associate it with glaucoma development. In this retrospective study, medical records of myopic patients referred for glaucoma examination from July 1, 2012 to March 30, 2016 were reviewed. Comprehensive ophthalmic examination including spectral-domain optical coherence tomography were performed. We measured the angle of anterior LC surface tilt against Bruch's membrane opening from optical coherence tomography images at the center of the clinical optic disc margin. In horizontal and vertical sections, the angles were defined as α and β, respectively. Patients were grouped according to the presence of glaucomatous damage and factors including optic nerve head morphologic parameters and LC tilt angles were compared between the 2 groups. Among 138 patients originally enrolled, 102 patients were finally analyzed. One eye from 1 patient was randomly chosen. Fifty-five eyes had glaucoma and 47 were normal. The degree of myopia and all optic nerve head morphologic parameters were not significantly different between the 2 groups. However, |α| and |β| were significantly larger in the glaucoma group (all P<0.001), and significances were maintained in multivariate analysis (P<0.001). Larger anterior LC surface tilt angles were related to the presence of glaucoma in normal-pressure myopic eyes. Angulation of the LC against Bruch's membrane opening plane might be associated with increased glaucoma susceptibility in myopic eyes. Further investigations are warranted before clinical utilization of LC tilt as glaucoma susceptibility biomarker.

Open-field arena boundary is a primary object of exploration for Drosophila

PubMed Central

Soibam, Benjamin; Mann, Monica; Liu, Lingzhi; Tran, Jessica; Lobaina, Milena; Kang, Yuan Yuan; Gunaratne, Gemunu H; Pletcher, Scott; Roman, Gregg

2012-01-01

Drosophila adults, when placed into a novel open-field arena, initially exhibit an elevated level of activity followed by a reduced stable level of spontaneous activity and spend a majority of time near the arena edge, executing motions along the walls. In order to determine the environmental features that are responsible for the initial high activity and wall-following behavior exhibited during exploration, we examined wild-type and visually impaired mutants in arenas with different vertical surfaces. These experiments support the conclusion that the wall-following behavior of Drosophila is best characterized by a preference for the arena boundary, and not thigmotaxis or centrophobicity. In circular arenas, Drosophila mostly move in trajectories with low turn angles. Since the boundary preference could derive from highly linear trajectories, we further developed a simulation program to model the effects of turn angle on the boundary preference. In an hourglass-shaped arena with convex-angled walls that forced a straight versus wall-following choice, the simulation with constrained turn angles predicted general movement across a central gap, whereas Drosophila tend to follow the wall. Hence, low turn angled movement does not drive the boundary preference. Lastly, visually impaired Drosophila demonstrate a defect in attenuation of the elevated initial activity. Interestingly, the visually impaired w1118 activity decay defect can be rescued by increasing the contrast of the arena's edge, suggesting that the activity decay relies on visual detection of the boundary. The arena boundary is, therefore, a primary object of exploration for Drosophila. PMID:22574279

Wideband metamaterial array with polarization-independent and wide incident angle for harvesting ambient electromagnetic energy and wireless power transfer

NASA Astrophysics Data System (ADS)

Zhong, Hui-Teng; Yang, Xue-Xia; Song, Xing-Tang; Guo, Zhen-Yue; Yu, Fan

2017-11-01

In this work, we introduced the design, demonstration, and discussion of a wideband metamaterial array with polarization-independent and wide-angle for harvesting ambient electromagnetic (EM) energy and wireless power transfer. The array consists of unit cells with one square ring and four metal bars. In comparison to the published metamaterial arrays for harvesting EM energy or wireless transfer, this design had the wide operation bandwidth with the HPBW (Half Power Band Width) of 110% (6.2 GHz-21.4 GHz), which overcomes the narrow-band operation induced by the resonance characteristic of the metamaterial. On the normal incidence, the simulated maximum harvesting efficiency was 96% and the HPBW was 110% for the random polarization wave. As the incident angle increases to 45°, the maximum efficiency remained higher than 88% and the HPBW remained higher than 83% for the random polarization wave. Furthermore, the experimental verification of the designed metamaterial array was conducted, and the measured results were in reasonable agreement with the simulated ones.

Scalable, "Dip-and-Dry" Fabrication of a Wide-Angle Plasmonic Selective Absorber for High-Efficiency Solar-Thermal Energy Conversion.

PubMed

Mandal, Jyotirmoy; Wang, Derek; Overvig, Adam C; Shi, Norman N; Paley, Daniel; Zangiabadi, Amirali; Cheng, Qian; Barmak, Katayun; Yu, Nanfang; Yang, Yuan

2017-11-01

A galvanic-displacement-reaction-based, room-temperature "dip-and-dry" technique is demonstrated for fabricating selectively solar-absorbing plasmonic-nanoparticle-coated foils (PNFs). The technique, which allows for facile tuning of the PNFs' spectral reflectance to suit different radiative and thermal environments, yields PNFs which exhibit excellent, wide-angle solar absorptance (0.96 at 15°, to 0.97 at 35°, to 0.79 at 80°), and low hemispherical thermal emittance (0.10) without the aid of antireflection coatings. The thermal emittance is on par with those of notable selective solar absorbers (SSAs) in the literature, while the wide-angle solar absorptance surpasses those of previously reported SSAs with comparable optical selectivities. In addition, the PNFs show promising mechanical and thermal stabilities at temperatures of up to 200 °C. Along with the performance of the PNFs, the simplicity, inexpensiveness, and environmental friendliness of the "dip-and-dry" technique makes it an appealing alternative to current methods for fabricating selective solar absorbers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wide angle reflection effects on the uncertainty in layered models travel times tomography

NASA Astrophysics Data System (ADS)

Majdanski, Mariusz; Bialas, Sebastian; Trzeciak, Maciej; Gaczyński, Edward; Maksym, Andrzej

2015-04-01

Multi-phase layered model traveltimes tomography inversions can be realised in several ways depending on the inversion path. Inverting the shape of the boundaries based on reflection data and the velocity field based on refractions could be done jointly or sequentially. We analyse an optimal inversion path based on the uncertainty analysis of the final models. Additionally, we propose to use post critical wide-angle reflections in tomographic inversions for more reliable results especially in the deeper parts of each layer. We focus on the effects of using hard to pick post critical reflections on the final model uncertainty. Our study is performed using data collected during standard vibroseis and explosive sources seismic reflection experiment focused on shale gas reservoir characterisation realised by Polish Oil and Gas Company. Our data were gathered by a standalone single component stations deployed along the whole length of the 20 km long profile, resulting in significantly longer offsets. Our piggy back recordings resulted in good quality wide angle refraction and reflection recordings clearly observable up to the offsets of 12 km.

The Activity of Comet 67P/Churyumov-Gerasimenko as Seen by Rosetta/OSIRIS

NASA Astrophysics Data System (ADS)

Sierks, H.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Rickman, H.; Koschny, D.

2015-12-01

The Rosetta mission of the European Space Agency arrived on August 6, 2014, at the target comet 67P/Churyumov-Gerasimenko. OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) is the scientific imaging system onboard Rosetta. OSIRIS consists of a Narrow Angle Camera (NAC) for the nucleus surface and dust studies and a Wide Angle Camera (WAC) for the wide field gas and dust coma investigations. OSIRIS observed the coma and the nucleus of comet 67P/C-G during approach, arrival, and landing of PHILAE. OSIRIS continued comet monitoring and mapping of surface and activity in 2015 with close fly-bys with high resolution and remote, wide angle observations. The scientific results reveal a nucleus with two lobes and varied morphology. Active regions are located at steep cliffs and collapsed pits which form collimated gas jets. Dust is accelerated by the gas, forming bright jet filaments and the large scale, diffuse coma of the comet. We will present activity and surface changes observed in the Northern and Southern hemisphere and around perihelion passage.

A brittle-ductile high- and low-angle fault related to the Kea extensional detachment (W Cyclades., Greece)

NASA Astrophysics Data System (ADS)

Rockenschaub, M.; Grasemann, B.; Iglseder, C.; Rice, A. H. N.; Schneider, D.; Zamolyi, A.

2010-05-01

Roll-back of the African Plate within the Eurasian-African collision zone since the Oligocene/Miocene led to extension in the Cyclades along low-angle normal fault zones and exhumation of rocks from near the brittle-ductile transition zone. On the island of Kea (W Cyclades), which represents such a crustal scale low-angle fault zone with top-to-SSW kinematics, remote sensing analysis of brittle fault lineaments in the Pissis area (W Kea) demonstrates two dominant strike directions: ca. NE-SW and NW-SE. From the north of Pisses southwards, the angle between the two main fault directions changes gradually from a rhombohedral geometry (ca. 50°/130° angle between faults, with the acute angle facing westwards) to an orthogonal geometry. The aim of this study is the development of this fault system. We investigate, if this fault system is related to the Miocene extension or if it is related to a later overprinting event (e.g. the opening of the Corinth) Field observations revealed that the investigated lineaments are high-angle (50-90° dip) brittle/ductile conjugate, faults. Due to the lack of marker layers offsets could only rarely be estimated. Locally centimetre thick marble layers in the greenschists suggest a displacement gradient along the faults with a maximum offset of less than 60 cm. Large displacement gradients are associated with a pronounced ductile fault drag in the host rocks. In some instances, high-angle normal faults were observed to link kinematically with low-angle, top-to-SSW brittle/ductile shear bands. Both the high- and the low-angle faults have a component of ductile shear, which is overprinted by brittle deformation mechanisms. In thin-section, polyphase mode-2 cracks are filled mainly with calcite and quartz (ultra)cataclasites, sometimes followed by further opening with fluid-related iron-rich carbonate (ankeritic) precipitation. CL analysis reveals several generations of cements, indicating multiple phases of cataclastic deformation and fluid infiltration. Ar/Ar white mica data from Pisses constrain ductile deformation to ca. 20 Ma. Since the high-angle faults show a continuum from ductile to brittle deformation, the Ar/Ar cooling ages suggest that faulting must have occurred in the Miocene. Consequently the high-angle faulting was genetically related to the SSW-directed low-angle extensional event and does not represent a later overprint related to a different kinematic event.

Optical and thermal simulation for wide acceptance angle CPV module

NASA Astrophysics Data System (ADS)

Ahmad, Nawwar; Ota, Yasuyuki; Araki, Kenji; Lee, Kan-Hua; Yamaguchi, Masafumi; Nishioka, Kensuke

2017-09-01

Concentrator photovoltaic (CPV) technology has the potential to decrease the cost of systems in the near future by using less expensive optical elements in the system which replace the receiving surface aperture and concentrate the sunlight onto small solar cells. One of the main concerns of CPV is the need for high precision tracking system and the relation to the acceptance angle. In this paper, we proposed a CPV module with concentration ratio larger than 100 times and wide acceptance angle. An optical simulation for the module with S-TIM2 glass as a lens material was conducted to estimate the optical performance of the module. Thermal and electrical simulation was also conducted using COMSOL Multiphysics and SPICE respectively to evaluate the working temperature and electrical characteristics of the multijunction solar cell under concentration conditions.

Generalized weighted ratio method for accurate turbidity measurement over a wide range.

PubMed

Liu, Hongbo; Yang, Ping; Song, Hong; Guo, Yilu; Zhan, Shuyue; Huang, Hui; Wang, Hangzhou; Tao, Bangyi; Mu, Quanquan; Xu, Jing; Li, Dejun; Chen, Ying

2015-12-14

Turbidity measurement is important for water quality assessment, food safety, medicine, ocean monitoring, etc. In this paper, a method that accurately estimates the turbidity over a wide range is proposed, where the turbidity of the sample is represented as a weighted ratio of the scattered light intensities at a series of angles. An improvement in the accuracy is achieved by expanding the structure of the ratio function, thus adding more flexibility to the turbidity-intensity fitting. Experiments have been carried out with an 850 nm laser and a power meter fixed on a turntable to measure the light intensity at different angles. The results show that the relative estimation error of the proposed method is 0.58% on average for a four-angle intensity combination for all test samples with a turbidity ranging from 160 NTU to 4000 NTU.

Large-angle cosmic microwave background anisotropies in an open universe

NASA Technical Reports Server (NTRS)

Kamionkowski, Marc; Spergel, David N.

1994-01-01

If the universe is open, scales larger than the curvature scale may be probed by observation of large-angle fluctuations in the cosmic microwave background (CMB). We consider primordial adiabatic perturbations and discuss power spectra that are power laws in volume, wavelength, and eigenvalue of the Laplace operator. Such spectra may have arisen if, for example, the universe underwent a period of `frustated' inflation. The resulting large-angle anisotropies of the CMB are computed. The amplitude generally increases as Omega is decreased but decreases as h is increased. Interestingly enough, for all three Ansaetze, anisotropies on angular scales larger than the curvature scale are suppressed relative to the anisotropies on scales smaller than the curvature scale, but cosmic variance makes discrimination between various models difficult. Models with 0.2 approximately less than Omega h approximately less than 0.3 appear compatible with CMB fluctuations detected by Cosmic Background Explorer Satellite (COBE) and the Tenerife experiment and with the amplitude and spectrum of fluctuations of galaxy counts in the APM, CfA, and 1.2 Jy IRAS surveys. COBE normalization for these models yields sigma(sub 8) approximately = 0.5 - 0.7. Models with smaller values of Omega h when normalized to COBE require bias factors in excess of 2 to be compatible with the observed galaxy counts on the 8/h Mpc scale. Requiring that the age of the universe exceed 10 Gyr implies that Omega approximately greater than 0.25, while requiring that from the last-scattering term in the Sachs-Wolfe formula, large-angle anisotropies come primarily from the decay of potential fluctuations at z approximately less than 1/Omega. Thus, if the universe is open, COBE has been detecting temperature fluctuations produced at moderate redshift rather than at z approximately 1300.

Seismic structure of western Mediterranean back-arc basins and rifted margins - constraints from the Algerian-Balearic and Tyrrhenian Basins

NASA Astrophysics Data System (ADS)

Grevemeyer, Ingo; Ranero, Cesar; Sallares, Valenti; Prada, Manel; Booth-Rea, Guillermo; Gallart, Josep; Zitellini, Nevio

2017-04-01

The Western Mediterranean Sea is a natural laboratory to study the processes of continental extension, rifting and back-arc spreading in a convergent setting caused by rollback of fragmented subducting oceanic slabs during the latest phase of consumption of the Tethys ocean, leading to rapid extension in areas characterized by a constant convergence of the African and European Plates since Cretaceous time. Opening of the Algerian-Balearic Basin was governed by a southward and westward retreating slab 21 to 18 Myr and 18 to15 Myr ago, respectively. Opening of the Tyrrhenian Basin was controlled by the retreating Calabrian slab 6 to 2 Myr ago. Yet, little is known about the structure of the rifted margins, back-arc extension and spreading. Here we present results from three onshore/offshore seismic refraction and wide-angle lines and two offshore lines sampling passive continental margins of southeastern Spain and to the south of the Balearic promontory and the structure of the Tyrrhenian Basin to the north of Sicily. Seismic refraction and wide-angle data were acquired in the Algerian-Balearc Basin during a cruise of the German research vessel Meteor in September of 2006 and in the Tyrrhenian Sea aboard the Spanish research vessel Sarmiento de Gamboa in July of 2015. All profiles sampled both continental crust of the margins surrounding the basins and extend roughly 100 km into the Algerian-Balearic and the Tyrrhenian Basins, yielding constraints on the nature of the crust covering the seafloor in the basins and adjacent margins. Crust in the Algerian-Balearic basin is roughly 5-6 km thick and the seismic velocity structure mimics normal oceanic crust with the exception that lower crustal velocity is <6.8 km/s, clearly slower than lower crust sampled in the Pacific Basin. The seismic Moho in the Algerian-Balearic Basin occurs at 11 km below sea level, reaching >24 km under SE Spain and the Balearic Islands, displaying typical features and structure of continental crust. Offshore Sicily, continental crust reaches 22 km. However, the Tyrrhenian Basin indicates a lithosphere with velocities increasing continuously from 3 km/s to 7.5 km/s, mimicking features attributed to un-roofed and hence serpentinized mantle. Therefore, even though the opening of both basins was controlled by slab rollback, the resulting structures of the basins indicate striking differences. It is interesting to note that the continent/ocean transition zone of the margins did not show any evidence for high velocity lower crustal rocks, in contrast to what has been sampled in Western Pacific arc/back-arc systems.

Accuracy of percutaneous pedicle screws for thoracic and lumbar spine fractures compared with open technique.

PubMed

Paredes, Igor; Panero, Irene; Cepeda, Santiago; Castaño-Leon, Ana M; Jimenez-Roldan, Luis; Perez-Nuñez, Ángel; Alén, Jose A; Lagares, Alfonso

2018-06-14

This study aimed to compare the accuracy of screw placement between open pedicle screw fixation and percutaneous pedicle screw fixation (MIS) for the treatment of thoracolumbar spine fractures (TSF). Forty-nine patients with acute TSF who were treated with transpedicular screw fixation from January 2013 to December 2016 were retrospectively reviewed. The patients were divided into Open and MIS groups. Laminectomy was performed in either group if needed. The accuracy of the screw placement, the evolution of the Cobb sagital angle postoperatively and at 12-month follow up and the neurological status were recorded. AO type of fracture and TLICS score were also recorded. Mean age was 42 years old. Mean TLICS score was 6,29 and 5,96 for open and MIS groups respectively. Twenty five MIS and 24 open surgeries were performed, and 350 (175 in each group) screws were inserted (7,14 per patient). Twenty-four and 13 screws were considered ̈out ̈ in the open and MIS groups respectively (Odds ratio 1,98. 0,97-4,03 p=0,056). The Cobb sagittal angle went from 13,3o to 4,5o and from 14,9o to 8,2o in the Open and MIS groups respectively (both p<0,0001). Loss of correction at 12-month follow up was 3,2o and 4,2o for the open and MIS groups respectively. No neurological worsening was observed. For the treatment of acute thoracolumbar fractures, the MIS technique seems to achieve similar results to the open technique in relation to neurological improvement and deformity correction, while placing the screws more accurately.

Optimal Control of Airfoil Flow Separation using Fluidic Excitation

NASA Astrophysics Data System (ADS)

Shahrabi, Arireza F.

This thesis deals with the control of flow separation around a symmetric airfoils with the aid of multiple synthetic jet actuators (SJAs). CFD simulation methods have been implemented to uncover the flow separation regimes and associated properties such as frequencies and momentum ratio. In the first part of the study, the SJA was studied thoroughly. Large Eddy Simulations (LES) were performed for one individual cavity; the time history of SJA of the outlet velocity profile and the net momentum imparted to the flow were analyzed. The studied SJA is asymmetrical and operates with the aid of a piezoelectric (PZT) ceramic circular plate actuator. A three-dimensional mesh for the computational domain of the SJA and the surrounding volume was developed and was used to evaluate the details of the airflow conditions inside the SJA as well as at the outlet. The vibration of the PZT ceramic actuator was used as a boundary condition in the computational model to drive the SJA. Particular attention was given to developing a predictive model of the SJA outlet velocity. Results showed that the SJA velocity output is correlated to the PZT ceramic plate vibration, especially for the first frequency mode. SJAs are a particular class of zero net mass flux (ZNMF) fluidic devices with net imparted momentum to the flow. The net momentum imparted to the flow in the separated region is such that positive enhancement during AFC operations is achieved. Flows around the NACA 0015 airfoil were simulated for a range of operating conditions. Attention was given to the active open and closed loop control solutions for an airfoil with SJA at different angles of attack and flap angles. A large number of simulations using RANS & LES models were performed to study the effects of the momentum ratio (Cμ) in the range of 0 to 11% and of the non-dimensional frequency, F+, in the range of 0 to 2 for the control of flow separation at a practical angle of attack and flap angle. The optimum value of Cμ as well as F+ were evaluated and discussed. The computational model predictions showed good agreement with the experimental data. It was observed that different angles of attack and flap angles have different requirements for the minimum value of the momentum coefficient, Cμ, in order for the SJA to be effective for control of separation. It was also found that the variation of F + noticeably affects the lift and drag forces acting on the airfoil. The optimum values of parameters during open loop control simulations have been applied in order to introduce the optimal open loop control outcome. An innovative approach has been implemented to formulate optimal frequencies and momentum ratios of vortex shedding which depends on angle of attack and static pressure of the separation zone in the upper chord. Optimal open loop results have been compared with the optimal closed loop results. Cumulative case studies in the matter of angle of attacks, flap angles, Re, Cμ and F+ provide a convincing collection of evidence to the following conclusion. An improvement of a direct closed loop control was demonstrated, and an analytical formula describing the properties of a separated flow and vortex shedding was proposed. Best AFC solutions are offered by providing optimal frequencies and momentum ratios at a variety of flow conditions.

Open-Access Electronic Textbooks: An Overview

ERIC Educational Resources Information Center

Ovadia, Steven

2011-01-01

Given the challenging economic climate in the United States, many academics are looking to open-access electronic textbooks as a way to provide students with traditional textbook content at a more financially advantageous price. Open access refers to "the free and widely available information throughout the World Wide Web. Once an article's…

The effect of transverse crack upon parametric instability of a rotor-bearing system with an asymmetric disk

NASA Astrophysics Data System (ADS)

Han, Qinkai; Chu, Fulei

2012-12-01

It is well known that either the asymmetric disk or transverse crack brings parametric inertia (or stiffness) excitation to the rotor-bearing system. When both of them appear in a rotor system, the parametric instability behaviors have not gained sufficient attentions. Thus, the effect of transverse crack upon parametric instability of a rotor-bearing system with an asymmetric disk is studied. First, the finite element equations of motion are established for the asymmetric rotor system. Both the open and breathing transverse cracks are taken into account in the model. Then, the discrete state transition matrix (DSTM) method is introduced for numerically acquiring the instability regions. Based upon these, some computations for a practical asymmetric rotor system with open or breathing transverse crack are conducted, respectively. Variations of the primary and combination instability regions induced by the asymmetric disk with the crack depth are observed, and the effect of the orientation angle between the crack and asymmetric disk on various instability regions are discussed in detail. It is shown that for the asymmetric angle around 0, the existence of transverse (either open or breathing) crack has attenuation effect upon the instability regions. Under certain crack depth, the instability regions could be vanished by the transverse crack. When the asymmetric angle is around π/2, increasing the crack depth would enhance the instability regions.

Exclusion of candidate genes from the chromosome 1q juvenile glaucoma region and mapping of the peripheral cannabis receptor gene (CNR2) to chromosome 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sunden, S.L.F.; Nichols, B.E.; Alward, W.L.M.

Juvenile onset primary open angle glaucoma has been mapped by linkage to 1q21-q31. Several candidate genes were evaluated in the same family used to identify the primary linkage. Atrionatriuretic peptide receptor A (NPR1) and laminin C1 (LAMC1) have been previously mapped to this region and could putatively play a role in the pathogenesis of glaucoma. A third gene, the peripheral cannabis receptor (CNR2) was not initially mapped in humans but was a candidate because of the relief that cannabis affords some patients with primary open angle glaucoma. Microsatellites associated with NPR1 and LAMC1 revealed multiple recombinations in affected members ofmore » this pedigree. CNR2 was shown to be on chromosome 1 by PCR amplification of a 150 bp fragment of the 3{prime} untranslated region in monochromosomal somatic cell hybrids (NIGMS panel No. 2). These primers also revealed a two allele single strand conformation polymorphism which showed multiple recombinants with juvenile onset primary open angle glaucoma in large pedigrees, segregating this disorder. The marker was then mapped to 1p34-p36 by linkage, with the most likely location between liver alkaline phosphatase (ALPL) and alpha-L-1 fucosidase (FUCA1).« less

Application of Bayes' to the prediction of referral decisions made by specialist optometrists in relation to chronic open angle glaucoma.

PubMed

Gurney, J C; Ansari, E; Harle, D; O'Kane, N; Sagar, R V; Dunne, M C M

2018-02-09

To determine the accuracy of a Bayesian learning scheme (Bayes') applied to the prediction of clinical decisions made by specialist optometrists in relation to the referral refinement of chronic open angle glaucoma. This cross-sectional observational study involved collection of data from the worst affected or right eyes of a consecutive sample of cases (n = 1,006) referred into the West Kent Clinical Commissioning Group Community Ophthalmology Team (COT) by high street optometrists. Multilevel classification of each case was based on race, sex, age, family history of chronic open angle glaucoma, reason for referral, Goldmann Applanation Tonometry (intraocular pressure and interocular asymmetry), optic nerve head assessment (vertical size, cup disc ratio and interocular asymmetry), central corneal thickness and visual field analysis (Hodapp-Parrish-Anderson classification). Randomised stratified tenfold cross-validation was applied to determine the accuracy of Bayes' by comparing its output to the clinical decisions of three COT specialist optometrists; namely, the decision to discharge, follow-up or refer each case. Outcomes of cross-validation, expressed as means and standard deviations, showed that the accuracy of Bayes' was high (95%, 2.0%) but that it falsely discharged (3.4%, 1.6%) or referred (3.1%, 1.5%) some cases. The results indicate that Bayes' has the potential to augment the decisions of specialist optometrists.

Anterior Chamber Angle Shape Analysis and Classification of Glaucoma in SS-OCT Images.

PubMed

Ni Ni, Soe; Tian, J; Marziliano, Pina; Wong, Hong-Tym

2014-01-01

Optical coherence tomography is a high resolution, rapid, and noninvasive diagnostic tool for angle closure glaucoma. In this paper, we present a new strategy for the classification of the angle closure glaucoma using morphological shape analysis of the iridocorneal angle. The angle structure configuration is quantified by the following six features: (1) mean of the continuous measurement of the angle opening distance; (2) area of the trapezoidal profile of the iridocorneal angle centered at Schwalbe's line; (3) mean of the iris curvature from the extracted iris image; (4) complex shape descriptor, fractal dimension, to quantify the complexity, or changes of iridocorneal angle; (5) ellipticity moment shape descriptor; and (6) triangularity moment shape descriptor. Then, the fuzzy k nearest neighbor (fkNN) classifier is utilized for classification of angle closure glaucoma. Two hundred and sixty-four swept source optical coherence tomography (SS-OCT) images from 148 patients were analyzed in this study. From the experimental results, the fkNN reveals the best classification accuracy (99.11 ± 0.76%) and AUC (0.98 ± 0.012) with the combination of fractal dimension and biometric parameters. It showed that the proposed approach has promising potential to become a computer aided diagnostic tool for angle closure glaucoma (ACG) disease.

Scanning electron microscopy of the trabecular meshwork: understanding the pathogenesis of primary angle closure glaucoma.

PubMed

Sihota, Ramanjit; Goyal, Amita; Kaur, Jasbir; Gupta, Viney; Nag, Tapas C

2012-01-01

To study ultrastructural changes of the trabecular meshwork in acute and chronic primary angle closure glaucoma (PACG) and primary open angle glaucoma (POAG) eyes by scanning electron microscopy. Twenty-one trabecular meshwork surgical specimens from consecutive glaucomatous eyes after a trabeculectomy and five postmortem corneoscleral specimens were fixed immediately in Karnovsky solution. The tissues were washed in 0.1 M phosphate buffer saline, post-fixed in 1% osmium tetraoxide, dehydrated in acetone series (30-100%), dried and mounted. Normal trabecular tissue showed well-defined, thin, cylindrical uveal trabecular beams with many large spaces, overlying flatter corneoscleral beams and numerous smaller spaces. In acute PACG eyes, the trabecular meshwork showed grossly swollen, irregular trabecular endothelial cells with intercellular and occasional basal separation with few spaces. Numerous activated macrophages, leucocytes and amorphous debris were present. Chronic PACG eyes had a few, thickened posterior uveal trabecular beams visible. A homogenous deposit covered the anterior uveal trabeculae and spaces. Converging, fan-shaped trabecular beam configuration corresponded to gonioscopic areas of peripheral anterior synechiae. In POAG eyes, anterior uveal trabecular beams were thin and strap-like, while those posteriorly were wide, with a homogenous deposit covering and bridging intertrabecular spaces, especially posteriorly. Underlying corneoscleral trabecular layers and spaces were visualized in some areas. In acute PACG a marked edema of the endothelium probably contributes for the acute and marked intraocular pressure (IOP) elevation. Chronically raised IOP in chronic PACG and POAG probably results, at least in part, from decreased aqueous outflow secondary to widening and fusion of adjacent trabecular beams, together with the homogenous deposit enmeshing trabecular beams and spaces.

Martian Low-Altitude Magnetic Topology Deduced from MAVEN/SWEA Observations

NASA Astrophysics Data System (ADS)

Xu, S.; Mitchell, D. L.; Liemohn, M. W.; Fang, X.; Ma, Y.; Luhmann, J. G.; Brain, D. A.; Steckiewicz, M.; Mazelle, C. X.; Connerney, J. E. P.; Jakosky, B. M.

2016-12-01

The Mars Atmosphere and Volatile Evolution (MAVEN) mission is the first to make comprehensive plasma and magnetic field measurements down to 150 km altitude over wide ranges of solar zenith angle, local time, longitude, and latitude. The Magnetometer (MAG) and the Solar Wind Electron Analyzer (SWEA) measure the magnetic field vector and the energy-angle distribution of superthermal (3-4600 eV) electrons along the spacecraft trajectory. This study presents pitch angle-resolved electron energy spectra, which we use to infer the plasma source regions sampled by the magnetic field line at large distances from the spacecraft, and in particular whether one or both ends of the magnetic field line have access to the day-side ionosphere. This is a key piece of information for deducing Martian magnetic topology. In the northern hemisphere at altitudes below 400 km, we find that magnetic field lines typically have both ends embedded in the collisional ionosphere, forming loops that connect distant regions on both the day and night hemispheres. This implies that this low-altitude region is dominated by closed crustal magnetic field lines, as opposed to the draped interplanetary magnetic field (IMF), which is prevalent at higher altitudes. Closed loops straddling the terminator allow transport of superthermal photoelectrons to the night hemisphere, which provides a source of ionization to support Mars' patchy night-side ionosphere. This study can also identify "open" field lines, with one end embedded in the ionosphere and the other end connected to the solar wind. This topology provides a conduit for ion outflow from the day-side ionosphere as well as precipitation of (possibly energized) solar wind electrons onto the atmosphere, which can also produce ionospheric patches and possibly auroral emissions.

Wicket gate trailing-edge blowing: A method for improving off-design hydroturbine performance by adjusting the runner inlet swirl angle

NASA Astrophysics Data System (ADS)

Lewis, B. J.; Cimbala, J. M.; Wouden, A. M.

2014-03-01

At their best efficiency point (BEP), hydroturbines operate at very high efficiency. However, with the ever-increasing penetration of alternative electricity generation, it has become common to operate hydroturbines at off-design conditions in order to maintain stability in the electric power grid. This paper demonstrates a method for improving hydroturbine performance during off-design operation by injecting water through slots at the trailing edges of the wicket gates. The injected water causes a change in bulk flow direction at the inlet of the runner. This change in flow angle from the wicket gate trailing-edge jets provides the capability of independently varying the flow rate and swirl angle through the runner, which in current designs are both determined by the wicket gate opening angle. When properly tuned, altering the flow angle results in a significant improvement in turbine efficiency during off-design operation.

Evaluation of eyes with relative pupillary block by indentation ultrasound biomicroscopy gonioscopy.

PubMed

Matsunaga, Koichi; Ito, Kunio; Esaki, Koji; Sugimoto, Kota; Sano, Toru; Miura, Katsuya; Sasoh, Mikio; Uji, Yukitaka

2004-03-01

To investigate changes in anterior chamber angle configuration with indentation ultrasound biomicroscopy gonioscopy of relative pupillary block (RPB). Cross-sectional study. This study included 26 eyes of 26 patients with RPB. We determined angle opening distance 500 and angle recess area using indentation ultrasound biomicroscopy gonioscopy and compared a small-sized standard eye cup with a new eye cup with an area for inducing pressure. Indentation ultrasound biomicroscopy images documented concavity of the iris in eyes with RPB. Both the new and the small standard eye cups widened the anterior chamber angle significantly (P <.0001) without causing corneal damage. Angle changes were significantly greater for the new eye cup design. Indentation ultrasound biomicroscopy gonioscopy is a useful technique for observation and diagnosis of RPB. Using a small standard or the newly designed eye cup, the procedure can be performed easily and without causing corneal damage.

The effect of finite geometry on the three-dimensional transfer of solar irradiance in clouds

NASA Technical Reports Server (NTRS)

Davies, R.

1978-01-01

Results are presented for a Monte Carlo model applied to a wide range of cloud widths and heights, and for an analytical model restricted in its application to cuboidally shaped clouds whose length, breadth, and depth may be varied independently; the clouds must be internally homogeneous with respect to their intrinsic radiative properties. Comparative results from the Monte Carlo method and the derived analytical model are presented for a wide range of cloud sizes, with special emphasis on the effects of varying the single scatter albedo, the solar zenith angle, and the scattering phase angle.