398 resultados para Humphrey, Alecia


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Drug dissolution and release characteristics from freeze-dried wafers and solvent-cast films prepared from sodium carboxymethylcellulose (CMC) have been investigated to determine the mechanisms of drug release from the two systems. The formulations were prepared by freeze-drying (wafers) or drying in air (films), the hydrated gel of the polymer containing paracetamol as a model soluble drug. Scanning electron microscopy (SEM) was used to examine differences between the physical structure of the wafers and films. Dissolution studies were performed using an exchange cell and drug release was measured by UV spectroscopy at 242 nm. The effects of drug loading, polymer content and amount of glycerol (films) on the release characteristics of paracetamol were investigated. The release profiles of paracetamol from the wafers and films were also compared. A digital camera was used to observe the times to complete hydration and dissolution of the wafers containing different amounts of CMC and how that impacts on drug release rates. Both formulations showed sustained type drug release that was modelled by the Korsmeyer–Peppas equation. Changes in the concentration of drug and glycerol (films) did not significantly alter the rate of drug release while increasing polymer content significantly decreased the rate of drug release from both formulations. The results show that the rate of paracetamol release was faster from the wafers than the corresponding films due to differences in their physical structures. The wafers which formed a porous network, hydrated faster than the more dense and continuous, (non-porous) sheet-like structure of the films.

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Solvent-cast films from three polymers, carboxymethylcellulose (CMC), sodium alginate (SA), and xanthan gum, were prepared by drying the polymeric gels in air. Three methods, (a) passive hydration, (b) vortex hydration with heating, and (c) cold hydration, were investigated to determine the most effective means of preparing gels for each of the three polymers. Different drying conditions [relative humidity - RH (6-52%) and temperature (3-45 degrees C)] were investigated to determine the effect of drying rate on the films prepared by drying the polymeric gels. The tensile properties of the CMC films were determined by stretching dumbbell-shaped films to breaking point, using a Texture Analyser. Glycerol was used as a plasticizer, and its effects on the drying rate, physical appearance, and tensile properties of the resulting films were investigated. Vortex hydration with heating was the method of choice for preparing gels of SA and CMC, and cold hydration for xanthan gels. Drying rates increased with low glycerol content, high temperature, and low relative humidity. The residual water content of the films increased with increasing glycerol content and high relative humidity and decreased at higher temperatures. Generally, temperature affected the drying rate to a greater extent than relative humidity. Glycerol significantly affected the toughness (increased) and rigidity (decreased) of CMC films. CMC films prepared at 45 degrees C and 6% RH produced suitable films at the fastest rate while films containing equal quantities of glycerol and CMC possessed an ideal balance between flexibility and rigidity.

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A substantial amount of the 'critical mass' of digital data available to scholarship contains place-names, and it is now recognised that spatial and temporal data points, including place-names, are a vital part of the e-research infrastructure that supports the use, re-use and advanced analysis of data using ICT tools and methods. Place-names can also be linked semantically to contribute to the web of data, and to enrich content through linking existing data, and identifying new collections for digitization to strategically enhance existing digital collections. However, existing e-projects rely on modern gazetteers limiting them to the modern and the near-contemporary. This workshop explored how to further integrate the wealth of historical place-name scholarship, and the resulting digital resources generated within UK academia, so enabling integration of local knowledge over much longer periods.

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Purpose: The authors estimated the retinal nerve fiber layer height (RNFLH) measurements in patients with glaucoma compared with those in age-matched healthy subjects as obtained by the laser scanning tomography and assessed the relationship between RNFLH measurements and optic and visual field status. Methods: Parameters of optic nerve head topography and RNFLH were evaluated in 125 eyes of 21 healthy subjects and 104 patients with glaucoma using the Heidelberg Retina Tomograph ([HRT] Heidelberg Engineering GmbH, Heidelberg, Germany) for the entire disc area and for the superior 70°(50°temporal and 20°nasal to the vertical midline) and inferior 70°sectors of the optic disc. The mean deviation of the visual field, as determined by the Humphrey program 24-2 (Humphrey Instruments, Inc., San Leonardo, CA, U.S.A) was calculated in the entire field and in the superior and inferior Bjerrum area. Result: Retinal nerve fiber layer height parameters (mean RNFLH and RNFL cross-sectional area) were decreased significantly in patients with glaucoma compared with healthy individuals. Retinal nerve fiber layer height parameters was correlated strongly with rim volume, rim area, and cup/disc area ratio. Of the various topography measures, retinal nerve fiber layer (RNFL) parameters and cup/disc area ratio showed the strongest correlation with visual field mean deviation in patients with glaucoma. Conclusion: Retinal nerve fiber layer height measures were reduced substantially in patients with glaucoma compared with age-matched healthy subjects. Retinal nerve fiber layer height was correlated strongly with topographic optic disc parameters and visual field changes in patients with glaucoma.

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Purpose: To compare two fast threshold strategies of visual field assessment; SITA Fast (HSF) and Tendency Orientated Perimetry (TOP), in detecting visual field loss in patients with glaucoma. Methods: Seventy-six glaucoma, ocular hypertensive and normal patients had HSF and TOP performed in random order. Quantitative comparisons for the global visual field indices - mean deviation and defect (MD) for HSF and TOP, and pattern standard deviation (PSD) for HSF and loss variance (LV) for TOP - were made using correlation coefficients. Humphrey global parameters were converted to Octopus equivalents, and method comparison analysis was used to determine agreement between the two strategies. Test duration times were compared using t-test. Sensitivity and specificity for these two algorithms were determined according to predetermined criteria. Results: High correlation coefficient values were obtained for MD measurements between HSF and TOP (r=-0.89, P

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Aims. To examine the antioxidant and anti-inflammatory effects of pomegranate polyphenols in obese patients with type 2 diabetes (T2DM) (n = 8) and in healthy nondiabetic controls (n = 9). Methods. Participants received 2 capsules of pomegranate polyphenols (POMx, 1 capsule = 753?mg polyphenols) daily for 4 weeks. Blood draws and anthropometrics were performed at baseline and at 4 weeks of the study. Results. Pomegranate polyphenols in healthy controls and in T2DM patients did not significantly affect body weight and blood pressure, glucose and lipids. Among clinical safety profiles, serum electrolytes, renal function tests, and hematological profiles were not significantly affected by POMx supplementation. However, aspartate aminotransferase (AST) showed a significant increase in healthy controls, while alanine aminotransferase (ALT) was significantly decreased in T2DM patients at 4 weeks (P <0.05), though values remained within the normal ranges. Among the biomarkers of lipid oxidation and inflammation, oxidized LDL and serum C-reactive protein (CRP) did not differ at 4 weeks in either group, while pomegranate polyphenols significantly decreased malondialdehyde (MDA) and hydroxynonenal (HNE) only in the diabetic group versus baseline (P <0.05). Conclusions. POMx reduces lipid peroxidation in patients with T2DM, but with no effects in healthy controls, and specifically modulates liver enzymes in diabetic and nondiabetic subjects. Larger clinical trials are merited.

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The energy transfer by stimulated Brillouin backscatter from a long pump pulse (15 ps) to a short seed pulse (1 ps)has been investigated in a proof-of-principle demonstration experiment. The two pulses were both amplified in differentbeamlines of a Nd:glass laser system, had a central wavelength of 1054 nm and a spectral bandwidth of 2 nm, and crossedeach other in an underdense plasma in a counter-propagating geometry, off-set by 10◦. It is shown that the energy transferand the wavelength of the generated Brillouin peak depend on the plasma density, the intensity of the laser pulses, and thecompetition between two-plasmon decay and stimulated Raman scatter instabilities. The highest obtained energy transferfrom pump to probe pulse is 2.5%, at a plasma density of 0.17ncr, and this energy transfer increases significantly withplasma density. Therefore, our results suggest that much higher efficiencies can be obtained when higher densities (above0.25ncr) are used.

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A 94 GHz waveguide Rotman lens is described which can be used to implement an amplitude comparison monopulse RADAR. In transmit mode, adjacent dual beam ports are excited with equal amplitude and phase to form a sum radiation pattern, and in receive mode, the outputs of the beam port pairs are combined using magic tees to provide a sum and a difference signal which can be used to calculate an angular error estimate for target acquisition and tracking. This approach provides an amplitude comparison monopulse system which can be scanned in azimuth and which has a low component count, with no requirement for phase shift circuitry in the array feed lines, making it suitable for mm-wave frequencies. A 12 input (beam ports), 12 output (array ports) lens is designed using CST Microwave Studio, and the predicted results are presented.

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A prototype scotopic sensitivity machine was used to evaluate pupillary and visual thresholds for 295 Indonesian children aged 1-5 y, most of whom were initially vitamin A-deficient. Subjects were tested 6 and 9 mo after receiving a high dose of vitamin A. A group of 136 older children was tested at 6 mo after dosing; all subjects underwent testing at 9 mo. After testing at 9 mo, children randomly received either a second high dose of vitamin A or placebo and were tested a final time 2 wk later. Children with abnormal pupillary thresholds had significantly higher relative dose responses (RDRs) (P < 0.01) and significantly lower serum retinol values (P = 0.05) than did normal children. The mean pupillary threshold rose (eg, retinal sensitivity fell) as vitamin A status deteriorated between 6 and 9 mo after initial dosing, and was significantly different from a group of normal American children tested previously (P < 0.001). After placebo-controlled dosing, the decline in pupillary and visual thresholds (rise in retinal sensitivity) was significant for children receiving vitamin A but not for children receiving placebo.

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OBJECTIVES:

To compare methods to estimate the incidence of visual field progression used by 3 large randomized trials of glaucoma treatment by applying these methods to a common data set of annually obtained visual field measurements of patients with glaucoma followed up for an average of 6 years.

METHODS:

The methods used by the Advanced Glaucoma Intervention Study (AGIS), the Collaborative Initial Glaucoma Treatment Study (CIGTS), and the Early Manifest Glaucoma Treatment study (EMGT) were applied to 67 eyes of 56 patients with glaucoma enrolled in a 10-year natural history study of glaucoma using Program 30-2 of the Humphrey Field Analyzer (Humphrey Instruments, San Leandro, Calif). The incidence of apparent visual field progression was estimated for each method. Extent of agreement between the methods was calculated, and time to apparent progression was compared.

RESULTS:

The proportion of patients progressing was 11%, 22%, and 23% with AGIS, CIGTS, and EMGT methods, respectively. Clinical assessment identified 23% of patients who progressed, but only half of these were also identified by CIGTS or EMGT methods. The CIGTS and the EMGT had comparable incidence rates, but only half of those identified by 1 method were also identified by the other.

CONCLUSIONS:

The EMGT and CIGTS methods produced rates of apparent progression that were twice those of the AGIS method. Although EMGT, CIGTS, and clinical assessment rates were comparable, they did not identify the same patients as having had field progression.