Search

Color rendering index (CRI) and luminous efficacy (LE) are two key performance factors of white LEDs (WLED). While most recent works in optics focus on methodology to improve these factors, little attention has been dedicated to chemical composition of materials. This paper studies the effect of Sr2.41F2.59B20.03O74.8:Eu0.12,Sm0.048 phosphor (SrSm), in terms of concentration and particle size on CRI and LE of 8500 K - WLEDs. Importantly, the molar mass of the componential ions in SrSm are calculated to shed light on the connection between the chemical composition of the material of interest and the performance of WLEDs. Results show that CRI can be improved to a value of around 86 by boosting red-light components in WLEDs, for all 3 major configurations: conformal, in-cup, and remote phosphor. CRI value tends to decrease with larger size of particles, while LE value goes in the reverse direction. On the other hand, both CRI and LE appear to be reduced at higher concentration of SrSm. This light attenuation is analyzed by using the Lambert-Beer law and Mie-scattering theory.

At the present time, color homogeneity and luminous flux are the two essentials utilized to appraise high-quality phosphor-converted LEDs (pcLEDs). In this paper, we present the search for the optimal selection among scattering enhancement particles (SEPs) to apply to improve these essentials for pcLEDs having correlated color temperature of 8500 K. The interested contenders include CaCO3, CaF2, SiO2, and TiO2. Each of them is added to yellow phosphor compounding (Y3Al5O12:Ce3+). Firstly, the LightTools program is employed to do the optical simulations. Secondly, the obtained results are verified and analyzed based on Mie scattering theory. The scattering computation of SEPs includes the scattering coefficients, the anisotropic scattering, the reduced scattering and the scattering amplitudes at 455 and 595 nm. It is observed that TiO2 particles provide the highest color homogeneity among the SEPs but the luminous flux reduces significantly as its concentration increases. By using CaCO3 particles, ...

Laser thermochemical recording is a flexible method for direct writing the binary planar structures (for instance, diffractive optical elements) by a local laser-induced oxidation of thin metal films. Unfortunately, due to excess of influencing parameters, search for regimes of high-resoluted recording could be complicated. The presented article proposes the way to analyze the hard-to-reach regimes of laser recording by modeling them with more convenient regimes (with different geometric and/or thermochemical parameters) based on their physical similarity.

To evaluate the safety, tolerability, pharmacokinetics, and dose-limiting toxicities of a single intravitreal (IVT) injection of PF-04523655, a 19-nucleotide, O-methyl stabilized, double-stranded small interfering ribonucleic acid targeting the RTP801 gene in patients with neovascular age-related macular degeneration (AMD).Prospective, phase 1, clinical multicentre trial, enrolled 27 patients with neovascular AMD unresponsive to prior treatment and best corrected visual acuity (BCVA) ≤ 20/200 in the study eye in stratum 1: (dose-escalating, open-label: 50 to 3000 μg of PF-04523655) and 27 patients who had potential to benefit from therapy and BCVA of ≤ 20/100 and ≥ 20/800 in stratum 2 (parallel, masked study of 1000, 1500, 2250, and 3000 μg of PF-04523655). The primary outcome was safety and tolerability assessment as well as pharmacokinetic profiling following a single IVT injection of PF-04523655.Doses of PF-04523655 ≥ 400 μg were generally detectable in the plasma at 1, 4, and 24 h post-injection. And all doses were below the lowest level of quantification by day 14. A single IVT injection of 50 to 3000 μg of PF-045237655 was generally safe and well tolerated over 24 months. There were no dose-limiting toxicities.A single IVT injection of PF-0523655 ≤ 3000 μg seems safe and well tolerated in eyes with neovascular AMD.

Aim There is evidence that interaction between angiotensin II type 1 receptor A1166C gene polymorphism and angio-tensin I-converting enzyme Insertion/Deletion gene variation might have an effect on the risk of myocardial infarction. The study was carried out in a population of 2244 male Caucasians, whose coronary anatomy was defined by means of coronary angiography. We analysed the relationship, on the risk of ischaemic heart disease, of angiotensin II type 1 receptor A1166C gene variation, not only to myocardial infarction but also to coronary artery disease, and its potential interaction with angio-tensin I-converting enzyme Insertion/Deletion gene polymorphism. Methods and Results No association was detected between angiotensin II type 1 receptor A1166C gene polymorphism and coronary artery disease. Similarly, there was no link to myocardial infarction, either in the total population or in low risk groups. In addition, most importantly, we found no interaction between angiotensin II type 1 receptor A1166C gene variation and angiotensin I-converting Insertion/Deletion polymorphism, either in connection with the risk of coronary artery disease or myocardial infarction. Conclusion This angiotensin II type 1 receptor A1166C gene variation is not associated with any detectable increase in risk of ischaemic heart disease. The findings of the present study do not suggest that, as regards risk of coronary artery disease and myocardial infarction, there is interaction between gene polymorphism and angiotensin I-converting enzyme Insertion/Deletion gene variation. The European Society of Cardiology

The study aims to identify the association between the baseline retinal vascular calibre and visual outcome of patients with diabetic macular oedema (DMO) treated with intravitreal ranibizumab.The 1-M field (as defined in the ETDRS study) of the digital colour fundus photographs of DMO patients who had been treated primarily with ranibizumab in a clinical trial was assessed. Of the 84 patients, 25 had gradable retinal photographs that could be subjected to analyses by the Interactive Vessel Analysis (IVAN) software at baseline. The average retinal vascular calibre of the six largest venules (CRVE) and the six largest arterioles (CRAE) in the peripapillary area (0.5 and 1 disc diameter from the optic disc margin) was measured. The relationship between CRVE and CRAE at baseline and the change in visual acuity at month 12 was assessed using the Mann-Whitney U test.Ten eyes from 10 patients who had shown an improvement of ≥2 lines of best corrected visual acuity (BCVA) at month 12 had a wider baseline CRVE (248.3±24.5 μm) compared with the 15 eyes from 15 patients who did not show the improvement of ≥2 lines (226.6±44.8 μm, P0.05). The baseline CRAE did not differ significantly in these patients (156.1±22.7 vs 142±17.5 μm, P=0.17).A wider baseline retinal venular calibre may be a predictor of better visual outcome in DMO eyes treated with ranibizumab. Further prospective studies with a larger sample size and a broader range of disease severity and visual acuity are needed to confirm this finding.

Patients with diabetic retinopathy (DR) may experience a reduction in retinal oxygen saturation (SO2). Close monitoring with a fundus ophthalmoscope can help in the prediction of the progression of disease. In this paper we present a noninvasive instrument based on structured illumination aimed at measuring the retina optical properties including oxygen saturation. The instrument uses two wavelngths one in the NIR and one visible, a fast acquisition camera, and a splitter system that allows for contemporaneous collection of images at two different wavelengths. This scheme greatly reduces eye movement artifacts. Structured illumination was achieved in two different ways, firstly several binary illumination masks fabricated using laser micro-machining were used, a near-sinusoidal projection pattern is ultimately achieved at the image plane by appropriate positioning of the binary masks. Secondarily a sinusoidal pattern printed on a thin plastic sheet was positioned at image plane of a fundus ophthalmoscope. The system was calibrated using optical phantoms of known optical properties as well as an eye phantom that included a 150μm capillary vessel containing different concentrations of oxygenated and deoxygenated hemoglobin.

This article discusses the role of home assessment and environmental modification in reducing the risk of falls and helping older adults and persons with disabilities live in the community. This article reviews the research on the efficacy of home environmental assessment and modification. Researchers agree that integrated risk-management programs that emphasize on multiple interventions, including professional home-hazard assessment, along with home modifications are most effective for improving function and reducing falls. Important steps for implementing home modifications for persons at risk of falling are discussed, including exploring fall-risk factors and the effects of home modifications, identifying what changes are needed through home assessments, identifying sources of payment, and finding qualified installers and products.

We present the development of setup composed of a retinal oximeter and a blood velocimeter implemented on a regular fundus ophthalmoscope. The oximeter part can acquire nine wavelength-dependent sub-images of the patient fundus in a single snapshot. The fundus image is projected on a large format CCD by an array of nine lenses and wavelength selection is provided by a filter array. Higher wavelength images help establishing melanin absorption, which is further extrapolated to shorter wavelength and subtracted from the absorption images. The remaining shorter wavelength subimages are used measure the oxygen saturation in the retina by fitting oxy- and deoxy-hemoglobin absorption curves. The setup was calibrated with optical phantoms of know optical properties. The velocimeter part of the setup relies on following clusters of erythrocytes to assess the velocity of blood.

Objectives: To assess direct effects of self-rated vision, home modifications, and limb functioning, and moderating effects of self-rated vision on change in functioning of upper and lower limbs on fall risk in older adults. Method: Logistic regression was used to analyze 2004 and 2006 waves of the Health and Retirement Study. Results: Effects of self-rated vision and home modifications in predicting falls decreased after controlling functioning in upper and lower extremities. Declines/gains in functioning across short periods of time superseded self-rated vision in predicting falls. No evidence was found for a moderating effect of vision status on limb functioning. Discussion: Poor self-rated vision may not be a good indicator of fall risk in older adults. Thus, for older adults with visual impairments, preserving residual limb functioning through exercise and activity has the important potential to reduce fall risk in addition to improving muscle and bone strength as well as improving balance and gait.

Aim:The aim of the study was to assess the safety and bioactivity of a single intravitreal injection of vascular endothelial growth factor (VEGF) Trap-Eye in subjects with diabetic macular oedema (DMO).Methods:Five subjects with DMO, foveal thickness ⩾250 μm measured by optical coherence tomography (OCT), and best-corrected visual acuity (BCVA) between 20/40 and 20/320, were enrolled. Each participant received a single intravitreal injection of 4.0 mg of VEGF Trap-Eye followed by a 6-week observation period. Outcome measures included safety and biological activity, including changes in BCVA and excess retinal thickness assessed by OCT.Results:Injections of VEGF Trap-Eye were well tolerated with no ocular toxicity. One patient had an unrelated serious adverse event: hospitalisation for cellulitis of the left foot 27 days after injection of VEGF Trap-Eye. Median baseline BCVA was 36 ETDRS letters read at 4 m (not ETDRS visual acuity score; Snellen equivalent: 20/50) and median baseline excess central 1 mm foveal thickness (FTH) was 108 μm. At 4 weeks after injection, the median excess FTH was 59 μm and the median improvement in BCVA was nine letters. At 6 weeks after injection, four of the five patients showed improvement in excess FTH (median 74 μm; 31% reduction from baseline, p = 0.0625) and four of the five showed improvement in BCVA (median improvement of three letters).Conclusions:A single intravitreal injection of 4.0 mg of VEGF Trap-Eye was well tolerated and preliminary evidence of bioactivity was detected. These findings support additional studies investigating multiple injections of VEGF Trap-Eye in patients with DMO.

In completion of oil and gas wells, zonal isolation requires proper cement placement with adequate bonding to the casing and formation. To achieve a successful cementing operation, the cement slurry should be properly designed to enable effective displacement of the drilling fluid from the annulus between the casing and wellbore. This is a complex process, involving displacement of viscoplastic fluids in eccentric annuli. The rheology, flow rate, and interfacial mixing of these fluids have direct impact on the displacement efficiency. Reliable computational modeling of the dynamics of the displacement process is beneficial to properly perform pre‐job design and post‐job analysis of the cementing operation. Furthermore, experimental data are also used to validate numerical predictions. This paper presents a flow visualization study using a helical flow device with adjustable annular eccentricity and rotation of the inner cylinder. Displacement experiments were conducted with a variety of non‐Newtonian fluids to simulate the cement slurry—drilling mud displacement process.

Straight vegetable oils provide cleaner burning and renewable alternatives to diesel fuels, but their inherently high viscosities compared to diesel are undesirable for diesel engines. Lowering the viscosity can be achieved by either increasing the temperature of the oil or by blending it with diesel fuel, or both. In this work the viscosity of diesel fuel and vegetable oil mixtures at differing compositions is measured as a function of temperature to determine a viscosity‐temperature‐composition relationship for use in design and optimization of heating and fuel injection systems. The oils used are olive, soybean, canola and peanut oils which are commercially available. All samples tested between 20°C and 80°C exhibit time‐independent Newtonian behaviour. A modified Arrhenius relationship has been developed to predict the viscosity of the mixtures as functions of temperature and composition.

Bevacizumab (Avastin, Genentech) is a recombinant humanised, full length, anti-VEGF monoclonal antibody that binds all isoforms of VEGF-A. It has been shown to prolong survival of patients with advanced colon cancer when combined with 5-fluorouracil.1 In this report, we describe the effect of bevacizumab in two patients with choroidal neovascularisation (CNV) secondary to pathological myopia, which was refractory to other treatment. ### Patient 1 AM is a 36 year old white man who was diagnosed with subfoveal CNV caused by pathological myopia (right eye = −11.50 D, left eye = −11.50 D) in his left eye in September 2002 for which he received three photodynamic therapy (PDT) treatments. He developed subfoveal CNV in his right eye in June 2003 and received one PDT treatment combined with an intravitreous injection of 4 mg of triamcinolone acetonide. In May 2004, he presented with recurrent subfoveal CNV in his right eye and refused PDT. Off-label use of bevacizumab was discussed and after informed consent, the patient decided to proceed. Just before treatment in July 2004, best corrected visual acuity (VA) was 20/40 in the right eye and 20/25 in the left eye. There was a ring of hyperpigmentation centred on the fovea with a surrounding ring of subretinal blood and substantial subretinal fluid in the right eye (fig 1A). An optical coherence tomography (OCT) scan through the centre of the fovea confirmed the presence of extensive subretinal fluid (fig 1B, asterisks) with subretinal tissue in the centre of the fovea (arrowheads). An OCT map showed severe thickening and subretinal fluid throughout the centre of the macula (foveal thickness 510 μm, macular volume 9.29 mm3). In the left eye, there were pigmentary changes and no subretinal blood or fluid (foveal thickness, 201 μm). In the right eye, the early phase of a fluorescein angiography (FA) …

Techniques for measuring the fundamental flow properties of as-mined Victorian brown coal suspensions are developed. Flow properties are presented for Morwell, Yallourn and Loy Yang coals as a function of concentration for fixed particle size distribution. Even at the relatively low solids concentration of 20 to 30 percent by weight, the suspensions exhibit complex non-Newtonian characteristics. Generally at high concentration, the suspensions are thixotropic with a shear rate dependent viscosity and exhibit a yield stress. The inherent thixotropy of the coals can be exploited and it is technically but perhaps not economically feasible to transport the as-mined coals in a pipeline. The power requirement to pump the coals in a pipeline is found to be 10 to 30 times that required to pump black coal in the Black Mesa pipeline in the U.S.A. The differences in the rheological properties of the three coals is related to the surface properties of the coal particle — expressed in terms of carboxylate and inorganic cation content, and to differences in the pore volume of the coals. The flow characteristics of one coal can be converted to that of another simply by varying either the carboxylate or ionic content of the suspension.