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In old subjects, the effect on visual performance of the interaction between the spectral power distribution of street lamps and the different types of intraocular lenses (IOLs) is unknown. Contrast threshold (CT) and reaction time (RT) were analysed in off-axis vision at mesopic illumination conditions provided by high-pressure sodium and metal-halide lamps, using a Maxwellian view optical system. Four groups of subjects participated: 10 young subjects, 20 elderly subjects with cataracts and the same subjects after cataract surgery were divided into two groups, 10 subjects implanted with a blue light-filtering and 10 subjects with a non-blue light-filtering IOL (NBIOL). Age-related cataract impairs detection and reaction capabilities; tasks that are nevertheless improved after surgery. The type of lamp does not affect both tasks in the case of the blue light-filtering IOL group, but it does in the NBIOL group. When comparing the two lenses, no detrimental effect of the blue light filter is observed in both tasks. In conclusion, at representative night-driving conditions, the spectral power distribution of the street lamp does not have a clinically relevant effect on visual tasks such as CT and visual RT in pseudophakic subjects, regardless of the type of IOL implanted. [ABSTRACT FROM AUTHOR]

The increasing replacement of traditional lamps by LED technology opens the door to research into visual performance under their multiple possible spectral power distributions. The correlated color temperature and S/P-ratio are considered parameters characterizing the spectrum of a light source. The lack of firm conclusions motivates the analysis in this work of the influence of LED spectrum, which is defined by the correlated color temperature and S/P-ratio, on a representative night-driving task, visual reaction time. A two-channel and four primaries photostimulator was used as set-up for measuring reaction time in off-axis vision, at mesopic illumination conditions and for a range of stimulus contrasts. The experimental conditions included a wide range of correlated color temperatures, ranging from 1870 to 6350 K, and different S/P-ratios for the same temperature. A total of 16 young subjects participated in the experiments. The results show significant shorter reaction times for those conditions in which the spectrum has greater short-wavelength content. This is corroborated by the greater stimulation of rods and S-cones obtained in the calculation of their excitation level. However, the definition of the spectrum using the correlated color temperature and S/P-ratio does not equally define the results obtained. For the same temperature, a higher S/P-ratio provides lower reaction time values, but for the same S/P ratio reaction time is independent of the temperature. LED light sources with high short-wavelength content provide faster response on the basis of a greater excitation of rods and S-cones. The S/P-ratio is the best parameter to justify the effect of spectrum on reaction time, as considers the spectral sensitivity of the visual system in its calculation. [ABSTRACT FROM AUTHOR]

The purpose of this work is to analyze the interaction between the spectral transmittance of old-aged subjects, before and after cataract surgery and blue light-filtering intraocular lens implantation, and the spectral power distribution of common street lamps, under conditions typical of nighttime driving. We analyzed contrast threshold and visual reaction time in off-axis vision at different mesopic illumination conditions provided by high-pressure sodium and metal halide lamps. Three groups of subjects with different spectral transmittances participated: young subjects as control group, old-aged subjects with senile cataracts and the same subjects after cataract surgery and blue light-filtering IOL implantation. A clear interaction appears between the spectral power distribution and the spectral transmittance, depending on the visual task. Transparent ocular media allow benefiting from the greater short-wavelength content of the halide lamp. However, cataracts increase contrast threshold and visual reaction time values and also affects how the spectral power distribution influences these visual tasks. After surgery and intraocular lens implantation, visual performance improves for both lamps and the blue light-filter seems to influence spectral transmittance, which affects visual performance under light provided by greater short-wavelength content lamps. Cataract surgery is responsible for an improvement in contrast threshold and visual reaction time tasks, though blue light-filtering of the intraocular lens seems to prevent the visual system from benefiting from lamps with greater emission at short wavelengths. [ABSTRACT FROM AUTHOR]

The model of artificial intelligence DENTOMO, which allows automated deciphering the CT in maxillofacial area, was developed and implemented in practical dentistry. The presented model is based on two convolutional neural networks, includes a database and knowledge base, harmonized with SNOMED Clinical Terms is a systematically organized computer processable collection of medical terms providing codes, terms, synonyms and definitions used in clinical documentation and reporting. The developed model automatically decodes cone beam CT images, identifies and classifies the anatomical structures of the human dental system, and reveals the pathological processes and their dynamics in dentistry system. This model generates the medical reports automatically. Testing of DENTOMO model demonstrated a reasonable effectiveness in deciphering the CT of dental system. The developed technology allows computerizing and objectifying interpretation of CT of the dental system. [ABSTRACT FROM AUTHOR]

This work discusses the relative significance of optical and neural mechanisms in letter contrast sensitivity under different conditions of environmental lighting. A study was carried out on 26 eyes with normal ocular health. Sixteen lighting conditions were obtained by combining different test luminances (from 10 cd/m2 to 600 cd/m2) and surround luminances (from 1 cd/m2 to 600 cd/m2). The results reveal a significant influence of optical factors (pupil size variations and glare effects) on contrast sensitivity when surround luminance changes, and a dominance of neural effects when test luminance changes. Furthermore, test size and illumination conditions are identified for which letter threshold contrasts are not sensitive to surround luminance changes. [ABSTRACT FROM PUBLISHER]

The influence of lighting of different spectral power distribution on letter contrast sensitivity has been studied. The different spectral power distributions were obtained by filtering or dimming tungsten halogen lamps. Measurements were made on 20 young and healthy individuals (25 eyes) whose monocular contrast sensitivities were measured with a natural pupil. Sixteen combinations of test and surround luminance with high or low correlated colour temperatures were studied in such a way that the influence of test luminance, surround luminance or colour temperature of both visual fields could be independently studied. Both test luminance and surround luminance influenced contrast sensitivity but correlated colour temperature did not. [ABSTRACT FROM AUTHOR]

An analytical method for the determination of aflatoxin B 1 in a tiger nut-based soft drinks named ‘horchata’ is described. The method is based on an immunoaffinity clean-up, followed by HPLC separation and fluorescence detection after electrochemical post-column derivatization. The detection limit ( S / N ?=?3) and the quantification limit ( S / N ?=?10) were 0.02 and 0.06?µg?kg -1 , respectively. The mean recovery at a level of 2?µg?l -1 was 88% ( n ?=?6) and the coefficient of variation was 9%. The method was applied to conduct a small market survey for a beverage named ‘horchata’ that is frequently consumed by parts of the population in Southern Europe. Twenty-two samples from Spanish and Belgian supermarkets were analysed. As a result, only one sample was found to contain aflatoxin B 1 at the limit of quantitation of the method. [ABSTRACT FROM AUTHOR]

An overview of liquid chromatographic methods, mainly employing fluorescence detection together with sample pre-treatment methods, is presented for the determination of the toxic group of fumonisin mycotoxins in various matrices. [ABSTRACT FROM AUTHOR]

The importance in experimental diabetic retinopathy of prostacyclin and nitric oxide (NO), as well as the possible effect of acetylsalicylic acid (ASA), are well known. To investigate the effect of two doses of aspirin in the prevention of retinal ischemia in streptozotocin-diabetic rats, we compared nondiabetic rats and diabetic rats after 1, 2 and 3 months of diabetes, and diabetic rats treated with 2 mg or 10 mg ASA/kg per day p.o. from the first day of diabetes. The parameters determined after 1, 2 and 3 months of development were platelet aggregation, thromboxane B2 (TxB2) production, 6-keto-prostaglandin F1α (stable metabolite of prostacyclin), NO, plasma nitrites/nitrates, and percentage retinal surface occupied by horseradish peroxidase (HRP)-permeable vessels. In diabetic rats platelet aggregation and thromboxane concentration were increased, and prostacyclin, NO and area occupied by HRP-permeable vessels were decreased. Acetylsalicylic acid reduced platelet aggregation, and lowered thromboxane production by 82%–99%. Prostacyclin production was inhibited by 92%–95% with 10 mg ASA/kg per day, and by 8%–20% with 2 mg ASA/kg per day. In diabetic rats NO production increased after 2 and 3 months of treatment to levels seen in nondiabetic rats. The reduction in HRP-permeable retinal surface decreased from a maximum of 87% in DR to 51% after treatment with 2 mg ASA/kg per day, and to 62% after 10 mg ASA/kg per day. We conclude that ASA (2 mg/kg per day and 10 mg/kg per day) increased NO production in streptozotocin-diabetic rats and reduced the degree of retinal ischemia. [ABSTRACT FROM AUTHOR]

Plasma levels of 8-methoxypsoralen (8-MOP) were determined by high-pressure liquid chromatography in 19 patients with psoriasis who were receiving bath-PUVA treatment, at different time points after the psoralen bath. The levels of 8-MOP varied between <5ng/ml (lower limit of detection) and 34 ng/ml, and we found a relationship between the plasma psoralen levels and the severity of the disease. [ABSTRACT FROM AUTHOR]

AIMS: To evaluate ibuprofen population pharmacokinetics in a large series of data collected in children with cystic fibrosis (CF) treated with high doses of ibuprofen (59 patients; 2-18 years), and to identify the main causes responsible for the considerable interindividual variability in ibuprofen serum levels. METHODS: Blood samples were collected during routine clinical care; serum ibuprofen concentrations were determined by HPLC. Fitting of the concentration/time data to a one compartment kinetic population model was performed by a non-linear mixed effect regression method. RESULTS: Body weight, dose, and ibuprofen dosage form (lysinate salt or the free acid form), for elimination clearance (CL/F); and body weight, dose, and fasting status for the apparent distribution volume (Vd/F) proved to be the covariates with influence in the model. The four factors identified helped to explain part of the interindividual variability observed, but the remaining unexplained variability made therapeutic drug monitoring absolutely essential. [ABSTRACT FROM AUTHOR]