SEARCH · PubMed Health

Results for “Color”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,153 records · Page 64Linked to original sources

PubMed1998

Assessment of left ventricular dyssynergy by color kinesis.

Color kinesis is a new echocardiographic technique based on acoustic quantification. It has been developed to facilitate the ability to identify contraction abnormalities and has been incorporated into a commercially available ultrasound imaging system. The potential of this technique to improve the qualitative and quantitative assessment of wall motion abnormalities is described. Evaluation of color-encoded images allows detection of decreased amplitude of endocardial motion in abnormally contracting segments as well as a shorter time of endocardial excursion in segments with severely decreased motion. Compared with off-line quantitative studies, color kinesis has the advantage to be used on-line, without time-consuming manual tracing of endocardial boundaries. In addition, a single end-systolic color image contains the entire picture of spatial and temporal contraction and can be digitally stored and retrieved. In patients with proven coronary artery disease, color kinesis had a sensitivity of 88%, a specificity of 77%, and an overall accuracy of 86% in identifying the presence of segmental dysfunction. The practical application of color kinesis might be to improve our ability to distinguish normal from hypokinesis, something that has always been difficult in clinical echocardiography. Segmental analysis of color kinesis images allows objective detection of dobutamine-induced regional wall motion abnormalities in agreement with conventional visual interpretation of the corresponding 2-dimensional views. A method for objective assessment of wall dynamics during dobutamine stress echocardiography would be of particular clinical value, because these images are even more difficult to interpret than conventional echocardiograms. Quantitative assessment of diastolic function may allow objective evaluation of segmental relaxation abnormalities, especially under conditions of pharmacologic stress testing. Acquisition of color kinesis images during dobutamine stress echocardiography, both transthoracic and transesophageal, may facilitate the assessment of hybernating but viable myocardium and enhance the sensitivity in the detection of coronary artery disease.

Echocardiography, Doppler, Color↗

PubMed1999

Dobutamine stress echocardiography at 7.5 mg/kg/min using color tissue Doppler imaging M-mode safely predicts reversible dysfunction early after reperfusion in patients with acute myocardial infarction.

Dobutamine stress echocardiography (DSE) is widely used to predict reversible left ventricular dysfunction, but evaluation by this method is subjective. The recently developed color tissue Doppler imaging (TDI) M-mode may permit objective and quantitative assessment of changes in wall motion induced by DSE. We tested the hypothesis that this new method can detect sensitively reversible dysfunction in the post-myocardial infarction setting. DSE with color TDI M-mode and conventional DSE were performed to predict reversible dysfunction in 53 patients at a mean of 3 days after infarction using 7.5 and 10 microg/kg/min of dobutamine. Follow-up regular echocardiography (4 weeks later) was used as the reference technique to define reversible dysfunction segments. To predict reversible dysfunction segments, the standard segmental wall motion score change on conventional DSE and the ratio of the segmental wall velocity difference at rest versus stress (7.5 and 10 microg/kg/ min) on DSE with color TDI M-mode (7.5-TDI-M and 10-TDI-M, respectively) were used. With 7.5 microg/kg/min of dobutamine, the sensitivity for predicting reversible dysfunction using color TDI M-mode (7.5-TDI-M) was significantly higher than that of conventional DSE (89% vs 73%, p <0.05) whereas specificities and predictive values were almost identical. With a 10-microg/kg/min dose, color TDI-M mode (10-TDI-M) and conventional DSE were not significantly different in predicting reversible dysfunction. With use of color TDI-M mode, regional wall motion during DSE was analyzed objectively and quantitatively. Moreover, combined TDI-M and conventional data were slightly superior to either mode alone. There were no arrhythmias during 7.5 microg/kg/min of dobutamine, but 9 arrhythmias occurred during the 10-microg/kg/min dose in patients with acute myocardial infarction. In conclusion, color TDI M-mode permits objective and quantitative assessment of regional ventricular wall motion and gives additional information for detecting reversible dysfunction in DSE. Improvement of sensitivity at a lower dose of dobutamine with color TDI-M mode may increase the safety of DSE in the post-myocardial infarction setting.

Angioplasty, Balloon, Coronary↗

PubMed1985

Visual half-field presentations of incongruent color-words reveal mirror-reversal of language lateralization in dextral and sinistral subjects.

Two experiments are reported concerning identification of left and right hemisphere dominance for language in dextral and sinistral subjects. A visual half-field (VHF) incongruent color-words paradigm was used. Color-words written in incongruent colors were presented either to the right or left half-field. Subjects were instructed to report the color, ignoring the color-word. Vocal reaction time (VRT) and frequency of errors were measured. Twenty dextral adult males were tested in Experiment 1. Results showed significantly more errors and a trend towards longer VRT:s when the words were presented in the right half-field, i.e. initially to the left hemisphere. No differences between half-fields were observed to color-stripes serving as control-stimuli. The results were followed up in Experiment 2 with a preselected sinistral group. All subjects in the sinistral group had revealed a left-ear-advantage (LEA) in a previous dichotic listening test, i.e. right hemisphere language dominance. The results from the VHF inconguent color-words test showed a reverse pattern of responding compared to the dextral group, i.e. more errors and longer VRTs when the color-words were initially presented to the right hemisphere.

Adult↗

PubMed2002

Determining eight colorants in milk beverages by capillary electrophoresis.

Milk beverages are popular because of their high nutritional value, and milk products that are enhanced with various fruit flavors are especially in high demand in Asia. Colorants are usually added to fruit flavored milk in order to increase its attraction and appearance, therefore, the detection and measurement of colorants in this type of beverage are relatively important for health issue reasons. Carminic acid, a natural colorant, along with tartrazine, Fast green FCF, Brilliant blue FCF, Allura Red AC, Indigo carmine, Sunset yellow FCF, and New coccine, which are seven different synthetic food colorants, are commonly used as food additives, therefore, this study would focus on the development of an analytical method for the detection of these common colorants in milk beverages. A high efficiency capillary electrophoresis separation method was finished by a pH 10.0 running buffer containing 7.0 mM beta-cyclodextrin, and the eight colorants were separated with baseline resolution within 9 min. In order to reduce the matrix interference resulting from the constituents of milk, a suitable polyamide column solid-phase extraction (SPE) was also investigated for milk sample pretreatment. The combination of the simple SPE pretreatment and the fast separation method of capillary electrophoresis, was able to determine successfully without matrix interference the content of these colorant additives in commercial milk beverages. The recoveries of the eight food colorants in milk beverages were better than 85% and the detection limits were also lower than 0.5 microg/ml by the developed method.

Ammonia↗

PubMed2000

Color and translucency of in vivo natural central incisors.

STATEMENT OF PROBLEM: The range of shades in shade guides is not consistent with natural teeth, and there is no information on the color and translucency of the natural tooth for all age groups. Therefore, it is important to obtain a database of the characteristics of the natural tooth from a wide age group. PURPOSE: This study obtained information on color and translucency of natural teeth for all age groups, and attempted to clarify the difference of the color and translucency between natural teeth and VITA Lumin Vacuum shade guide. MATERIAL AND METHODS: Natural central incisors of 87 subjects (42 men and 45 women; age range from 13 to 84 years) and 16 shades of VITA Lumin Vacuum shade guide were evaluated. Color and translucency of 5 sites, each 1.0 mm in diameter, on the surfaces of individual teeth were measured for L*, a*, and b*, using a color computer according to CIELAB color spaces. RESULTS: At the center site, negative correlation was found between age and L*, with positive correlation between age and b*. Both a* and b* of the natural tooth increased when moving in the direction of the cervical site, but translucency decreased in the direction of the root. The a* value for the natural tooth was significantly higher than those for VITA Lumin Vacuum shade guide. CONCLUSION: This study found that the older the subject, the darker and more yellow the color at the center site of the natural tooth. Both reddish and yellowish colors of natural teeth tend to increase from the incisal to cervical, whereas translucency decreases. Red-green chromaticity of VITA Lumin Vacuum shade guide was not distributed to cover the natural tooth.

Adolescent↗

PubMed1995

Color changes in dry-pigmented maxillofacial elastomer resulting from ultraviolet light exposure.

Five dry pigments and one maxillofacial elastomer were evaluated for color changes (delta E) resulting from prolonged exposure to two types of ultraviolet light. The elastomer, pigments, and pigmented elastomers were subjected to each ultraviolet light source for 400, 600, and 1800 hours, and delta E color shifts were determined. The unpigmented elastomer underwent minimally perceptible color change after 600 hours of exposure to both types of ultraviolet light. Two pigments underwent substantial color change after 400 hours, whereas the remaining three pigments remained color stable after 1800 hours. It was concluded that for the materials tested, early color changes in a prosthesis may be the result of degradation of certain ultraviolet light-susceptible pigments, whereas longer term color shifts may be caused by color changes within the elastomer.

Analysis of Variance↗

PubMed1998

Color stability of dental composites as a function of shade.

STATEMENT OF PROBLEM: The selection of shade of composites for restorative applications may have a significant effect on color degradation through environmental exposure. PURPOSE: This study characterized the color changes in composites as a function of shade through environmental effects such as ultraviolet light exposure. MATERIAL AND METHODS: Five shades of two composites were subjected to ultraviolet light exposure at 37 degrees C for 24 hours after initial storage for 24 hours in distilled water at 37 degrees C. The lightness and chromaticity values of color were measured both before and after ultraviolet light exposure with a Minolta Chromameter. The total color change as well as changes in the lightness and chromaticity values were measured in the CIE L*a*b* scale and analyzed to monitor color degradation, if any. RESULTS: Color degradation was a significant function of shade and occurred primarily as an increase in yellowness. Color changes increased with the lightness of the shade in both composite systems. CONCLUSION: The lighter shades of composites were likely to be subject to higher color degradation through environmental effects of ultraviolet light exposure.

Analysis of Variance↗

PubMed1999

Color stability of facial silicone prosthetic polymers after outdoor weathering.

STATEMENT OF PROBLEM: Color deterioration of silicone prosthetic elastomers affects the life expectancy of facial prostheses in a service environment. PURPOSE: This study investigated the color stability of 3 nonpigmented silicone elastomers (Silskin 2000, Elastosil M3500, Ideal) exposed to outdoor weathering for 1 year. MATERIAL AND METHODS: A tristimulus colorimeter was used to evaluate the color differences (DeltaE*) of the silicone elastomers every 2 months. Ten disk-shaped specimens for each material were tested. Data were analyzed with a repeated measures ANOVA and Student-Newman-Keuls test at a significance level of alpha = .05. RESULTS: All silicone elastomers showed visually detectable, mean color differences (DeltaE* > 2.0), that ranged from 2.13 to 3.98. Silskin 2000 showed greater color differences (P <.05) compared with Elastosil M3500 and Ideal, which showed similar behavior (P >.05). CONCLUSION: Outdoor exposure of silicone facial elastomers for 1 year resulted in visually detectable color differences. Duration of exposure and silicone elastomer were significant factors that affected color stability. Silskin 2000 was significantly less color stable than Elastosil M3500 and Ideal, which were not statistically significantly different from each other.

Analysis of Variance↗

PubMed2004

Color stability of provisional prosthodontic materials.

STATEMENT OF PROBLEM: Discoloration of provisional prosthodontic materials may result in patient dissatisfaction and additional expense for replacement. PURPOSE: The purpose of this study was to determine the color stability of 5 provisional prosthodontic materials before and after immersion in distilled water or coffee for 20 days or exposure to ultraviolet (UV) light for 24 hours. MATERIAL AND METHODS: A total of 105 disc-shaped specimens (20+/-0.1 mm by 1+/-0.05 mm) were fabricated with 5 provisional prosthodontic materials: polyethyl methacrylate resins (Trim II), polymethyl methacrylate resins (Duralay; Alike), and bis-acryl methacrylate resin (Luxatemp; Integrity), according to manufacturers' instructions (n=21). Seven specimens of each material were randomly selected and immersed individually in distilled water (60 degrees C) or coffee (37 degrees C) for 20 days or exposed to UV irradiation for 24 hours, respectively. Color was measured as CIE L*a*b* with a colorimeter before and after the immersion or UV exposure. Color change (Delta E) was calculated and data were analyzed with 1-way ANOVA and the Tukey multiple comparisons test (alpha=.05). RESULTS: For specimens immersed in water, the color change of bis-acryl-methacrylate-based provisional materials (Integrity and Luxatemp) was significantly less than that of 3 methyl/ethyl methacrylate-based provisional materials (Trim II, Alike, and Duralay) (P<.002). After immersion in coffee, the 3 methyl/ethyl methacrylate-based provisional materials exhibited significantly less color change compared to the 2 bis-acryl methacrylate-based provisional materials (P<.0001). After ultraviolet irradiation, 2 bis-acryl methacrylate-based provisional materials showed significantly less color change than any of the 3 methyl/ethyl methacrylate-based provisional materials (P<.0001). CONCLUSION: Luxatemp and Integrity (bis-acryl-methacrylate-based resins) demonstrated acceptable color stability and were the most color-stable provisional prosthodontic materials tested compared to the methyl/ethyl methacrylate-based resins.

Analysis of Variance↗

PubMed2000

Is a "color effect" demonstrated for hair analysis of carbamazepine?

Psillakis et al. have reported on the concentration of carbamazepine recovered from hair samples collected from patients receiving this anti-seizure medication under medical supervision and determined that their was a high correlation between dose and quantitation of recovered analyte. The analyte was identified by two techniques, FPIA (Abbott TDx) and HPLC and the correlation was high for both procedures. In the literature on hair analysis some have suggested that analyte concentration in hair is critically dependent on hair color. In reporting their data Psillakis et al. reported the hair color of each patient but made no attempt to analyze their results in relation to color. This article performs a secondary analysis of the Psillakis et al. data in order to determine whether there is a hair color effect discernible in the recovery of carbamazepine from hair. Analysis of this data set for both the FPIA and HPLC by one-way analysis of variance fails to identify a color effect at p = .05. Weighting the data for per-patient dosage values fails to discern a color effect. Examination of all possible two-color comparisons also fails to identify a statistically significant effect for any subset of combinations. These data suggest that carbamazepine does not exhibit a color effect when using either FPIA or HPLC assay methods.

Adolescent↗

PubMed1998

The contribution of color to visual memory in X-chromosome-linked dichromats.

We used a recognition memory paradigm to assess the visual memory of X-chromosome-linked dichromats for color images of natural scenes. The performance of 17 protanopes and 14 deuteranopes, who lack the second (red-green opponent) subsystem of color vision, but retain the primordial (yellow-blue opponent) subsystem, was compared with that of 36 color normal observers. During the presentation phase, 48 images of natural scenes were displayed on a CRT for durations between 50 and 1000 msec. Each image was followed by a random noise mask. Half of the images were presented in color and half in black and white. In the subsequent query phase, the same 48 images were intermixed with 48 new images and the subjects had to indicate which of the images they had already seen during the presentation phase. We find that the performance of the color normal observers increases with exposure duration. However, they perform 5-10% better for colored than for black and white images, even at exposure durations as short as 50 msec. Surprisingly, performance is not impaired for the dichromats, whose recognition performance is also better for colored than for black and white images. We conclude either that X-chromosome-linked dichromats may be able to compensate for their reduced chromatic information range when viewing complex natural scenes or that the chromatic information in most natural scenes, for the durations tested, is sufficiently represented by the surviving primordial color subsystem.

Adult↗

PubMed2001

Regulating colored textile wastewater by 3/31 wavelength ADMI methods in Taiwan.

The wastewater from textile dyeing facilities is difficult to treat satisfactorily because of high compositional variability and high color intensity. To reduce colored effluents discharged into watercourses, the government of Taiwan adopted the Effluent True Color Standard in 1998. The true color discharge limit is 400 American Dye Manufactures Institute (ADMI) units. The adopted analytical method is the ADMI Tristimulus Filter Method (3 wavelength (WL) method), and the 31 WL ADMI method might be also adopted as an alternative for color value measurement. The refractory nature of textile dyes and the introduction of this new regulation present an environmental challenge to the Taiwanese textile industry. The main objectives of this study were to (1) evaluate the efficacy of current wastewater treatment systems for controlling the colored textile wastewater discharges, and (2) evaluate the correlations between 3 and 31 WL ADMI methods. Ten representative textile wastewater treatment facilities employing biological and chemical coagulation treatment technologies were selected to perform a 10-consecutive-day effluent sampling and analysis. Results show that a significant difference between 3 and 31 ADMI methods was observed. These two ADMI methods cannot be substituted for each other, and the discharge standard should be determined based on the selected testing method. Investigation results also suggest that the commonly used wastewater treatment technology (biological + chemical coagulation) fails to effectively remove dye from the colored textile wastewater. Sodium hypochlorite (NaOCl) addition was applied by most facilities as the temporary post-polishment step to comply with the color discharge standard.

Chemistry Techniques, Analytical↗

PubMed2003

Using gray-scale and two different techniques of color Doppler sonography to detect prostate cancer.

OBJECTIVES: To correlate the findings of prostate color Doppler sonography (CDS) with those of site-specific transrectal ultrasound-guided core biopsy; to evaluate the significance of two different color presets in detecting prostate cancer compared with gray-scale transrectal ultrasonography; and to compare the accuracy of conventional gray-scale transrectal ultrasound (CGS)-guided biopsy with CDS-guided biopsy. METHODS: Seventy patients were enrolled in this prospective study. CDS was performed before biopsy. Two color presets were used: CDS-1 (high sensitivity) and CDS-2 (high specificity). The color flow was graded on a scale from 0 to 2+. At the completion of the color grading, color maps were constructed. In each case, CDS-guided biopsy was performed followed by CGS-guided biopsy (six sextant biopsies and focal lesional biopsies). RESULTS: The cancer detection rate was 33%, 31%, and 27% for CGS-guided biopsy, CDS-1, and CDS-2, respectively. CDS-1 was more sensitive than CDS-2 (81% versus 60%) but both presets had similar specificities (79% versus 82%). CGS-guided biopsy yielded a sensitivity of 90%, a specificity of 38%, and a positive and negative predictive value of 34% and 83%, respectively. A biopsy strategy combining hypoechoicity with increased color flow increased the specificity to 97%, positive predictive value to 68%, and negative predictive value to 84%, but its sensitivity was low (18%). CONCLUSIONS: Our experience suggests that low-velocity, high-sensitivity color is superior to all other CDS settings. The presence of focal peripheral zone hypervascularity at CDS is associated with a high likelihood of prostate cancer. However, only a combination of CDS guidance with six sextant biopsies may achieve maximal sensitivity and specificity.

Aged↗

PubMed2003

Color stability and hardness in dental composites after accelerated aging.

OBJECTIVES: To investigate the color and microhardness changes of five chemically- and five light-curing composites as a function of accelerated aging from light exposure. MATERIALS AND METHODS: From each material five composite specimens were embedded in epoxy resin prior to determining the Knoop microhardness of the surface. For analyzing the color DeltaE*=f((L*a*b*)) with a spectrophotometer, three discs per composite were prepared. After measuring the baseline for hardness and color the same specimens were exposed to a xenon arc light and water in a Weather-Ometer machine for a total radiant energy of 150 kJ/m2 and 122 h. The microhardness and the color were again determined following the aging treatment. RESULTS: Each material showed a significant increase in hardness after aging treatment (p<0.05). Comparing the hardness changes (in %) of the light-cured materials with the chemically cured materials, no significant difference could be found. Perceptible color differences could be observed for all the materials. Three brands showed small differences with DeltaE*=1.6-2.2, while four composites had DeltaE* ranging from 6.2 to 15.5. A significant correlation between hardness values and color changes could not be established. CLINICAL SIGNIFICANCE: The findings suggest that, since light-curable materials showed significantly more resistance to color changes after accelerated aging by light and water than chemically-cured materials, they may be more esthetically acceptable. Color changes were not correlated with surface hardness changes of the materials after aging.

Analysis of Variance↗

PubMed2004

Influence of illuminating and viewing aperture size on the color of dental resin composites.

OBJECTIVES: The objective was to evaluate the difference in the color of dental resin composites by the illuminating and viewing aperture sizes. The influences of the color measuring geometry, standard illumination and surface roughness on the color were also determined. METHODS: Color of five brands of resin composites of A2 shade was measured after-polymerization and after-polishing. Color was measured according to the CIE L(*)a(*)b(*) color scale with the SCE and SCI geometry under the CIE standard illumination of A and D65. The illuminating/viewing aperture sizes were 11 mm/8 mm (8 mm) and 3 mm/3 mm (3 mm). RESULTS: Regardless of the measuring geometry, CIE L(*), a(*) and b(*) values measured at 3 mm were lower than those at 8 mm. Changes in L(*), a(*) and b(*) values by the difference in the aperture size were 17.22-21.32, 3.43-6.64 and 13.82-16.81, respectively, and the color difference (DeltaE(*)) was 16.23-27.87 with the SCE geometry. Regardless of the aperture size, DeltaE(*) values caused by polishing measured with the SCE were significantly higher than those with the SCI. SIGNIFICANCE: Aperture size, measuring geometry and surface conditions of specimen should be considered when comparing the result of color measurement.

Colorimetry↗

PubMed1997

Color distribution of three regions of extracted human teeth.

OBJECTIVES: Knowledge of human tooth color and its distribution are critical to the understanding of shade matching in esthetic dentistry. The color of human teeth shows a gradation from the gingival to the incisal region. There have been many reports in the literature on the distribution of color in teeth, but not in the CIE 1976 L*a*b* system. This study was conducted to determine the color distribution in three regions in a sample of human teeth and express the results in Munsell notation, CIE 1976 L*a*b* and CIE delta E* color differences. The hypothesis of this research was that it is possible to detect significant differences in the color parameters of the three distinct regions in teeth. METHODS: All of the teeth used in this study were extracted, cleaned and stored in artificial saliva. Prior to measurement, the teeth were removed from the solution and mounted in a holder to ensure consistent measurements. Spectral data were collected using a GE recording spectrophotometer, CIE chromaticity coordinates calculated using CIE illuminant C and 1931 observer data, and conversions made to L*, a*, b* and Munsell notation. The results were analyzed by ANOVA and Scheffé's multiple comparisons test. RESULTS: The mean L*, a*, b*s were 72.6, 1.5, 18.4 for gingival, 72.4, 1.2, 16.2 for middle, and 71.4, 0.9, 12.8 for incisal. Average Munsell parameters were 1.2 Y 7.1/2.7 for gingival, 1.3 Y 7.1/2.4 for middle, and 1.4 Y 7.0/1.9 for incisal. The mean CIE delta E* between the gingival and incisal regions of the 95 teeth showed a clinically significant difference of 8.2. SIGNIFICANCE: The distribution of color was identified for three regions of the tooth. A statistical analysis determined that there are statistically significant color differences between the regions, and these differences are also clinically significant. This information is beneficial when esthetic restorations are required.

Adolescent↗

PubMed1992

Color vision in honeybees.

Theoretical and experimental investigations of the color vision system in honeybees are reviewed. Grassmann's model and receptor models of color vision are discussed with respect to the problem of color difference. A recent analysis of the bee's color opponent coding system is presented in brief. Predictions for the spectral sensitivity of color opponent coding neurons derived directly from the color opponent coding (COC) model and predictions for the Bezold-Brücke color shift and the spectral discrimination function derived from the model via color difference formula are presented. The predictions are compared with electrophysiological data and with choice proportions of behavioral experiments, respectively.

Animals↗

PubMed1984

Color perimetry of glaucomatous visual field defects.

A color video tangent screen has been devised, using microcomputer control of a video display to produce colored perimetric test objects matched in luminance to a white surround at 10-foot lamberts . Perimetric isopters for varying degrees of color saturation were determined by kinetic perimetry. This form of color perimetry was used to examine one eye of each of 40 patients with open-angle glaucoma as well as 20 glaucoma-suspect patients. For the first 23 eyes with manifest glaucomatous visual field defects, a masked comparison was made between the results of color perimetry and conventional perimetry with a Goldmann perimeter. For these 23 eyes, color perimetry did as well as luminance perimetry in 14, was less sensitive in 2, and was more sensitive in 7. All defects that were detectable by conventional perimetry were successfully demonstrated by the color method. Such defects often appeared to be greater in extent when mapped by the color method as compared to conventional luminance perimetry.

Aged↗