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PubMed1992

Constrained least-squares estimation of surface curvature and dioptric power from meridional measurements.

A dioptric power or surface curvature may be presumed or known to be of some particular type, for example spherical, or astigmatic and with a particular nearest equivalent sphere. Such knowledge or presumption represents a constraint on the power or curvature. This paper shows how meridional measurements can be used to obtain least-squares estimates of surface curvature or dioptric power under the constraint.

Mathematics↗
PubMed2005

[Soft X-ray reflectometer with laser produced plasma source].

A soft X-ray reflectometor with laser-produced plasma source developed in the authorial lab is presented for the measurements of efficiencies of gratings, transmission of filter and reflectance of multilayer coatings. The reflectometer is composed of a soft X-ray laser-produced plasma source, a grazing incidence monochromator with a constant deviation angle, a vacuum chamber, a sample table, a photo-electronic unit and a computer controlling unit. The working wavelength is from 8 to 30 nm and the maximum sample size is 130 mm long by 120 mm wide by 120 mm high. In order to test the performances of the reflectometer, the reflectivity of multilayer coatings was obtained by using this device. The measured results agree well with the theoretical calculation. The reproducibility of measured reflectance is +/-0.6%.

Algorithms↗
PubMed2005

[Synthesis and character of megastigmatrienone].

In this synthetic route, the raw materials are obtained easily and the conditions of reactions are smoothly. The products in some main procedures of the route have high yieds. This synthetic route is a new way of the compound, there hasn't been reported anywhere. It needs further studies to be practically applied. According to this synthetic routes, the authors studied technolygical conditions of the reactions of every step. Some products are analyzed by refractive index, IR, HNMR, and MS and confirmed its structure.

Biological Products↗
PubMed2005

[New biconcave prism contact lens for vitreous surgery in gas-filled eyes].

PURPOSE: To obtain a surgical contact lens with adequate operative field in vitreous surgery of gas-filled eyes. METHODS: We designed a new biconcave prism contact lens for gas-filled eyes by improving the material and the design of the lens (prism angle, radius and area of front concave of the lens). The operative field was calculated by a simulation using the ray tracing method for cases of simultaneous phaco-vitrectomy surgery, vitrectomy of pseudophakic eyes, and vitrectomy without phaco-surgery. For this study, a prototype of the newly designed lens was made and used for vitrectomy of gas-filled eyes. RESULTS: The calculated operative field was about 47 degrees (central angle) for vitrectomy of pseudophakic eyes and vitrectomy without phaco-surgery. In cases of simultaneous phaco-vitrectomy surgery, the operative field can be varied continuously from 47 to 145 degrees (central angle) by adjusting the viscoelastic material in the anterior chamber. Appropriate visual field, good binocular vision, and visibility of the peripheral region were obtained in the vitrectomy of gas-filled eyes. CONCLUSION: The newlydesigned contact lens is useful for viewing the fundus during the vitrectomy of gas-filled eyes.

Air↗
PubMedDate not supplied

Simultaneous determination of chlorinated bacteriostats in cosmetic and pharmaceutical products.

A high-performance liquid chromatography method has been developed for simultaneous determination of triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) and triclocarban (3,4,4'-trichlorocarbanilide) in cosmetic and pharmaceutical products. The two compounds could be separated on a Nucleosil C(18) column and eluted with acetonitrile and water (70:30, v/v) as the mobile phase and detected with a differential refractive index detector. The retention times of triclosan and triclocarban were 5.81 and 2.99 min, respectively. The results obtained were in good agreement with those obtained by a differential pulse voltammetric method.

Anti-Infective Agents, Local↗
PubMedDate not supplied

Spatial and angular distribution of light incident on coatings using Mie-scattering Monte Carlo simulations.

We show the results of Mie-scattering Monte Carlo models developed to simulate the optical properties of light incident on particle-containing coatings. The model accommodates mixtures of particles with different sizes and complex refractive indices, enabling the simulation of formulations, including pigments. The simulation tracks trajectories of photons as they propagate through the turbid medium, calculating both angular and spatial light intensity distributions. Scalar quantities such as total transmission and reflection, and haze and diffuse reflectance, are also calculated.

Computer Simulation↗
PubMedDate not supplied

Hemp-seed and olive oils: their stability against oxidation and use in O/W emulsions.

Hemp-seed oil has several positive effects on the skin: thanks to its unsaturated fatty acid (PUFA) content it alleviates skin problems such as dryness and those related to the aging process. We present a comparative study of hemp-seed and olive oils, determining some physicochemical indices and evaluating their stability against oxidation. The peroxide value of hemp-seed oil was below 20, the threshold limit for edible oils. Hemp-seed oil was less stable against peroxidation than olive oil, but MDA and MONO assays showed its stability to be above expectations. The chlorophyll contained in extra virgin olive oil had a higher photostability than that contained in hemp-seed oil, possibly due to the larger amount of antioxidant in the olive oil. A certain amount of Vitamin E was found in hemp-seed oil. Since quality analyses indicated that hemp-seed oil is relatively stable, emulsions were prepared with the two oils, and their stability and rheological characteristics were tested. Some of the resulting gel-emulsions were suitable for spraying on the skin.

Cannabis↗
PubMedDate not supplied

Refractive index matching and clear emulsions.

Refractive index (RI) matching is a unique way of making clear emulsions to meet market trends. However, RI matching has not been sufficiently investigated in terms of physical principles and methodologies. Snell's law (n2 sin r2= n1 sin r1) is applicable to cosmetic emulsions. When oil phase and water phase have equal RI (n2 = n1) values, light will not bend as it strikes obliquely at the emulsion interface. Instead, light is transmitted through the emulsion without refraction, which produces clarity. Theoretical RI values in solution can be calculated with summation of the product of the weight percentage and refractive index of each ingredient (RI(mix) = [W1 x n1 + W2 x n2 + W3 x n3 + + Wn x nn]Wtau). Oil-phase RI values are normally at 1.4 or higher. Glycols are used to adjust the water phase RI, since they typically have larger RI values than water. Noticeable deviations from calculated RI values are seen in experimentally prepared solutions. Three basic deviation types are observed: negative, positive, and slightly negative or positive, which can occur in glycol aqueous solutions at different concentrations. The deviations are attributed to changes in molecular interaction between molecules in solution, which can lead to changes in specific gravity. Negative RI deviation corresponds to a decrease in specific gravity, and positive RI deviation corresponds to an increase in specific gravity. RI values will deviate from calculated values since an increase or decrease in specific gravity leads to a change in optical density.

Cosmetics↗
PubMedDate not supplied

A new, heavier-than-water silicone oil: a solution of perfluorohexyloctane in polydimethylsiloxane.

PURPOSE: To pre p a re and explore new solutions of semifluorinated alkane in silicone oil, which have a specific gravity slightly higher than silicone oil and vitreous fluid (referred to in the following as heavier-than-water silicone oils (HWSs), and to investigate, in vitro, whether HWSs can be used to plug retina holes, while allowing dehydration of the subretinal space. METHODS: HWS solutions were pre p a red with silicone oil 5000 and perfluorohexyloctane (F6H8). The stability was investigated under different conditions. The viscosity was determined by means of a capillary viscometer. The surface and interface tension were measured using the ring method. RESULTS: HWSs are insoluble in an aqueous medium. Densiron(R)68 (HWS 1.06) is a transparent homogeneous liquid which is slightly heavier (1.06 g/cm3) than water and has a refractive index close to that of vitreous liquid. Densiron68 (HWS 1.06) has a low viscosity (1480 mPas) and interface tension (40.82 mN/m), making it an effective tamponade in the surgical treatment of an inferior detached retina. In addition, the interfaces between Densiron68 and other perfluorocarbon liquids are clearly visible. However, the interface layer between Densiron68 and water is not clear. Finally, all HWSs are stable over the long term at ambient temperatures, as well as physically and thermally resistant. CONCLUSIONS. Due to its physiochemical properties, Densiron68 could meet the requirements for a heavier-than-water tamponade.

Adult↗
PubMed2005

[Study of photocatalytic performance of TiO2 membrane for oleic acid by FTIR-ATR technique].

The TiO2 membranes were prepared on glass, ceramic tile and aluminum pieces by Sol-Gel and PVD methods. A fast and exact evaluation on the photocatalytic self-cleaning performance of the membrane materials was achieved by FTIR-ATR technique using oleic acid which was laid on the surface of the membrane. The hydrophilic property of the samples was also determined by the contact angle with water. The results showed that both the TiO2 membrane prepared on glass by the Sol-Gel and PVD methods displayed good photo-induced hydrophilic property and degradation activity of oleic acid, and no difference in hydrophilic property, but the former was a little superior to the latter in photocatalytic activity. The photocatalytic conversion of oleic acid on the TiO2/glass, TiO2/ceramic tile and TiO2 aluminum piece were 92%, 85% and 46%, respectively after illumination 3.5 h, showing a distinct effect of support material property on TiO2 photocatalytic performance. The results suggested that the photocatalytic activity of TiO2 membrane coated on insulator support was higher than that coated on conductor support.

Adsorption↗
PubMed2005

[Studies on relics conservation by diffuse reflectance spectroscopy].

A diffuse reflectance spectroscopic method was developed to investigate relics conservation with a self-made fiber optics reflectance spectrophotometer. With this technique (1) identifying pigments on the color relics was done by comparing the shapes of reflectance spectra and the positions of reflectance peaks or first derivative peaks with those of related standard pigments; (2) changes of surface states of metals were monitored. From the investigation on the reflectance spectra of copper and its rust product, we can easily get some information about the metal surface, so diffuse reflectance spectroscopy shows special function in the research on metal surface; (3) the diffuse reflectance spectroscopic characteristics of the materials used in protection and restoration of cultural heritages were studied, which can help us choose proper protecting and restoring materials. From our studies it was verified that diffuse reflectance spectroscopy is a quick, simple and non-destructive analytical technique. The study makes diffuse reflectance spectroscopy a new means for relic protection, and opens a new application area for diffuse reflectance spectroscopy as well.

Coloring Agents↗
PubMed2005

Ray tracing analysis of overlapping objects in refraction contrast imaging.

We simulated refraction contrast imaging in overlapping objects using the ray tracing method. The easiest case, in which two columnar objects (blood vessels) with a density of 1.0 [g/cm3], run at right angles in air, was calculated. For absorption, we performed simulation using the Snell law adapted to the object's boundary. A pair of bright and dark spot results from the interference of refracted X-rays where the blood vessels crossed. This has the possibility of increasing the visibility of the image.

Angiography↗
PubMed2005

Proteomic changes in bovine heart mitochondria with age: using a novel technique for organelle separation and enrichment.

Separation and enrichment of organelles from complex biological mixtures are important for proteomic analysis. Two widely used current standard techniques to isolate individual organelles include differential and density-gradient centrifugation. Although these techniques have proven useful for processing small volumes of sample, multiple rounds of centrifugation are required when performing a large-scale purification. In this report, we have introduced a novel technique: continuous-flow ultracentrifugation using a sucrose gradient to separate, accumulate, and highly enrich bovine heart mitochondria in one step. To demonstrate the advantage of the technique, mitochondrial proteins from two different bovine hearts (3-8 mo and 18-30 mo old) were examined. For each age group, 100 g of bovine heart tissue were homogenized by a blending procedure. After removal of the nuclei, the entire remaining homogenate was loaded onto a proteomics continuous-flow ultracentrifuge to separate and enrich the organelles. Fractions were collected and mitochondria-enriched fractions were identified by Western blot analysis. To study the protein profile changes with aging in the mitochondrial proteome, the mitochondria-enriched fractions were applied to two-dimensional gel electrophoresis. The resulting two-dimensional PAGE gels were subsequently analyzed by image analysis software to identify proteins unique to each age group and proteins with at least twofold differences in protein expression. These proteins were then digested with trypsin and identified by mass spectrometer. Significant differences in the protein profiles of the two differently aged mitochondria preparations were found. The continuous-flow ultracentrifugation technique was demonstrated to be a powerful tool for separation and enrichment of organelles and their sub-types.

Aging↗
PubMed2005

Biomolecular interactions by Surface Plasmon Resonance technology.

The Surface Plasmon Resonance (SPR) technique makes it possible to measure biomolecular interactions in real-time with a high degree of sensitivity and without the need of label. The information obtained is both qualitative and quantitative and it is possible to obtain the kinetic parameters of the interaction. This new technology has been used to study a diverse set of interaction partners of biological interest, such as protein-protein, protein-lipids, protein- nucleic acids or protein and low molecular weight molecules such as drugs, substrates and cofactors. In addition to basic biomedical research, the SPR biosensor has recently been used in food analysis, proteomics, immunogenicity and drug discovery.

Animals↗
PubMed2005

[Accuracy of the SRK II, SRK/T, Holladay and Hoffer Q IOL power calculation formulas in hyperopic patients after phacoemulsification].

PURPOSE: Comparison of the SRK II, SRK/T, Holladay and Hoffer Q formulas accuracy, in calculating IOL power in hyperopic patients. MATERIAL AND METHODS: 34 eyes of 22 hyperopic patients, 15 women and 7 men, at the age from 19 to 85 years old, after phacoemulsification with PCIOL implantation, operated between 1998 and 2004 were analysed retrospectively. The power of IOL was calculated using the SRK/T formula and ranged from 28.5 to 35.0 D. The axial length ranged from 19.6 mm to 21.99 mm. The obtained refraction was measured with autorefractometer from 9 days to 37 month after operation, mean 6 month. In addition, the theoretical target refraction for the implanted IOL was calculated using the SRK II, Holladay and Hoffer Q formulas and the differences between the target and obtained refraction for all the formulas were compared. RESULTS: The best accuracy of IOL power calculation was obtained with the Hoffer Q formula. The Holladay, SRK/T and SRK II formulas gave worse results respectively. CONCLUSIONS: For the purpose of IOL power calculation in hyperopic patients the Hoffer Q or Holladay formula should be chosen from those mentioned above. Nevertheless, miscalculation exceeding 3D also happens in case of using them. The use of SRK II and SRK/T is not recommended. To improve the results other formulas utilising precise measurements of the anterior segment should be applied. If it is impossible then attention should be paid to improving traditional biometry measurements.

Adult↗
PubMed2005

[Coherent oscillations of the molecular state of protein in live cells].

The paper describes results of experimental studies of changes in the refractive index of the live cell (human erythrocyte) substance. The measurements were carried out using automated interference microscope. Oscillations of the refractive index were detected with the amplitude 5-10% and period 1 x 10(3)-3 x 10(3). In other words, oscillations with a near one hour period is equal to 10-45 min. It is supposed that these oscillations may result from coherent changes in the state of protein molecules.

Erythrocytes↗
PubMed2006

[Principles and applications of overpressured-layer chromatography].

The principles and applications of overpressured-layer chromatography (OPLC) are reviewed. The instrument and the operation modes of OPLC are introduced, followed by a description of the influence factors of OPLC and how to solve typical problems during the use of OPLC. In addition, the typical applications of OPLC are also summarized.

Chromatography↗