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Multiple Exposures (multiple + exposure)
Selected AbstractsExposure Fusion: A Simple and Practical Alternative to High Dynamic Range PhotographyCOMPUTER GRAPHICS FORUM, Issue 1 2009T. Mertens I.4.8 [Image Processing]: Scene Analysis , Photometry, Sensor Fusion Abstract We propose a technique for fusing a bracketed exposure sequence into a high quality image, without converting to High dynamic range (HDR) first. Skipping the physically based HDR assembly step simplifies the acquisition pipeline. This avoids camera response curve calibration and is computationally efficient. It also allows for including flash images in the sequence. Our technique blends multiple exposures, guided by simple quality measures like saturation and contrast. This is done in a multiresolution fashion to account for the brightness variation in the sequence. The resulting image quality is comparable to existing tone mapping operators. [source] Intermittent exposure to low-concentration paraphenylenediamine can be equivalent to single, higher-dose exposureCONTACT DERMATITIS, Issue 5 2007Jonathan M. L. White Hair dye allergy is an important and increasingly common cause of allergic contact dermatitis. The role of repeated exposure in elicitation of allergy has not previously been extensively studied. We have therefore compared elicitation between single and intermittent exposure to paraphenylenediamine (PPD). 23 subjects known to be allergic to PPD from positive patch tests were exposed to 0.3% and 0.03% PPD, both in petrolatum and water, for 5 min at the same site every day for up to 8 D. In the same subjects, single exposures were also performed at different sites, from 5 to 40 min. Other experiments exposed rat skin to radiolabelled PPD as one-off application or multiple exposures. There were 8 reactions in the cumulative exposure site using 0.3% PPD in aqueous solution. In 7 of these, there was an exact correlation with reaction to the cumulative time needed for repeat exposures to elicit a reaction and the time needed for a reaction to the single exposure. There were no reactions to 0.03% PPD in water or pet under either type of exposure condition. There was also a positive correlation between grade of original reaction in clinic (+++, ++, +) and appearance/intensity of elicitation reactions. In the animal study, cumulative time and single exposure time sites correlated with regards to retention of radiolabelled substance within the skin. This study therefore demonstrates for the first time that, over the time period tested, the allergenic component of PPD accumulates in the skin. Hence, intermittent exposure to lower concentrations of PPD may be equivalent to higher concentration, one-off exposure. [source] Effects of carbaryl on green frog (Rana clamitans) tadpoles: Timing of exposure versus multiple exposuresENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2003Michelle D. Boone Abstract The majority of studies on pesticide impacts have evaluated the effects of single exposures. However, multiple exposures to a pesticide may be more prevalent. The objective of our study was to determine how multiple exposures versus single exposure at different times during development affected survival to metamorphosis, tadpole survival, tadpole mass, and tadpole developmental stage of green frog (Rana clamitans) tadpoles reared at low and high density in outdoor cattle tank ponds. Tadpoles were exposed to carbaryl zero, one, two, or three times at 14-d intervals. We applied single doses of carbaryl at one of three times, specifically during early, mid, or late development. Overall, we found that multiple exposures had a greater impact than single exposures during development. More individuals reached metamorphosis in ponds exposed to multiple doses of carbaryl compared with controls, indicating that the presence of carbaryl stimulated metamorphosis. The presence of carbaryl in the aquatic environment also resulted in more developed tadpoles compared with controls. Tadpoles in control ponds did not reach metamorphosis and were less developed than individuals exposed to carbaryl; this effect indicates that, under ideal conditions, green frogs could overwinter in ponds so that greater size could be attained before metamorphosis in the following spring or summer. Our study demonstrated the importance of including realistic application procedures when evaluating the effects of a pesticide and that multiple exposures to a short-lived pesticide are more likely to affect an amphibian population. [source] Evidence of occult HCV genotypes in haemophilic individuals with unapparent HCV mixed infectionsHAEMOPHILIA, Issue 4 2008C. PARODI Summary., Individuals with haemophilia who received non heat-treated factor concentrates were likely to undergo multiple exposures to the hepatitis C virus (HCV). Therefore, HCV mixed-genotype infections might be more frequent in these patients than in the general population. Their prevalence is extremely variable in similar groups of patients tested by different assays due to the fact that currently available genotyping techniques are not suitable to detect multiple HCV genotypes in a viral population. As an HCV viral reservoir, the peripheral blood mononuclear cell (PBMC) might harbor viral variants distinct from the genotypes detected in plasma. We investigated the presence of HCV genotypes in a group of chronically infected haemophilic patients in the PBMC compartment using a non-stimulated cell culture system that allows the detection of the HCV genome in culture supernatants. We compared them to the HCV genotypes found in plasma samples. Cell culture experiments performed with PBMC demonstrated the presence of additional HCV genotypes that were undetected in the corresponding plasma samples with the same genotyping technique. Although mixed infections at HCV genotype level became evident in 5.6% of the patients (16/288), the culture methodology increased the number of HCV infections with multiple genotypes to 62.5% (10/16) (P < 0.0001). Once more, the role of mononuclear cells as HCV viral reservoirs is emphasized. Considering minor strains could influence the outcome of treatment, detection of covert HCV mixed-genotype infections might be essential for choosing the adequate therapeutic regimen. [source] Reformulated BeneFix®: efficacy and safety in previously treated patients with moderately severe to severe haemophilia BHAEMOPHILIA, Issue 3 2007T. LAMBERT Summary. BeneFix®, the only recombinant factor IX (FIX), has been reformulated. The reformulation involves a change in diluent and allows for more concentrated infusions of recombinant FIX. A double-blind, randomized, pharmacokinetic (PK) crossover study demonstrated that reformulated BeneFix was bioequivalent to original BeneFix and follow-up PK evaluation after 6 months of treatment demonstrated the PK stability of reformulated BeneFix after multiple exposures. Favourable efficacy and safety profiles, consistent with those already well-established for original BeneFix, were observed: 81.1% of haemorrhages resolved with only a single infusion; 85.3% of initial treatment response ratings were Excellent or Good; more than half of the subjects using reformulated BeneFix for routine prophylaxis (11 of 17, 64.7%) had no spontaneous haemorrhages during their 6,12 month course of prophylactic treatment, with an overall spontaneous bleeding rate of 0.72 year,1; and for the single surgical procedure (knee washing), treatment was rated Useful. In addition, there was no FIX inhibitor development, allergic-type manifestations, or thrombogenic complications with more than 1100 infusions (nearly 5.2 million IUs) administered in this trial. All efficacy and safety outcomes from this study were achieved with more concentrated recombinant protein infusions than that possible with original BeneFix, and utilization of the 2000 IU per vial dosage strength, newly introduced with the reformulated product, was high (>62%). The reformulation of BeneFix allows smaller delivery volumes and an increased choice of dosage strengths without altering the PK properties (including incremental recovery and half-life) or the established efficacy and safety profile of recombinant FIX. [source] Avoidable burden of disease: conceptual and methodological issues in substance abuse epidemiologyINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 4 2006Jürgen Rehm Abstract Determining the proportion of avoidable disease burden attributable to substance use is important for both policy development and intervention implementation. Current epidemiological theory has in principle provided a method to estimate avoidable burden of disease and the available statistical tools can provide first rough estimates. The method described in this paper, and its statistical procedures, are exemplified to estimate avoidable burden of tobacco-related disease in Canada. However, further effort is needed to find solutions in the methodological details, namely exposure measurement, risk factor multidimensionality, estimation of changes in exposure distribution over time, and estimation of risk relationships from multiple exposures changing over time with multiple endpoints (causal webs). The impetus to begin refining methods to obtain better starting points for estimating avoidable burden of disease is obvious and should be carried through in order to see real changes through evidence-based policy and intervention. Copyright © 2006 John Wiley & Sons, Ltd. [source] Attributable fractions for partitioning risk and evaluating disease prevention: a practical guideTHE CLINICAL RESPIRATORY JOURNAL, Issue 2008Geir E. Eide Abstract Introduction:, The attributable fraction (AF) is used for quantifying the fraction of diseased ascribable to one or more exposures. The methodology and software for its estimation has undergone a considerable development during the last decades. Objectives:, To introduce methods for: (i) apportioning excess risk to multiple exposures, groups of exposures and subpopulations; (ii) graphical description; and (iii) survival data. Results:, Adjusted, sequential and average AFs are reasonable measures obtainable with standard software. The latter two both sum up to the combined AF for a set of exposures. The average AFs are independent of the exposures' ordering. For an ordered, preventive strategy, scaled sample space cubes illustrate the effects on the risk of disease from stepwise exposure removal. Pie charts illustrate the portions of the total risk ascribed to different exposures or risk-profiles. Attributable hazard fraction, AF before time t, and AF within study incorporate time to disease and interventions. Conclusions:, The practice of crude calculations of AFs in epidemiology should be abandoned. Further development of methods for AFs with survival data and possibly linking it to causal modelling is of interest. Please cite this paper as: Eide GE. Attributable fractions for partitioning risk and evaluating disease prevention: a practical guide. The Clinical Respiratory Journal 2008; 2: 92,103. [source] MotherSafe: Review of three years of counselling by an Australian teratology Information ServiceAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 2 2009Joy Marie LIM Background: MotherSafe was established in January 2000 at the Royal Hospital for Women as Australia's first ,purpose-built' Teratogen Information Service and since then has received over 75 000 calls regarding exposures during pregnancy and lactation. Aim: To describe the patterns of use of MotherSafe over a three-year period. Methods: Retrospective descriptive epidemiological study using data from the database established at MotherSafe. Records from all the calls logged at MotherSafe between January 2005 and December 2007 were analysed to determine total number of calls, demographic characteristics of callers, including age, caller category and postcode, reason for call, source of referral and type of exposure. Results: A total of 47 138 calls were recorded to the MotherSafe service from January 2005 to December 2007. The majority of calls were regarding exposures in pregnancy (55%) and breast-feeding (38%). Average age of patients was 32.3 years. Of the calls made, 81.9% (38 485 of 46 968) were by consumers (the pregnant or lactating woman herself or a relative). The most common primary exposure categories were: over-the-counter medications (11.3%), psychotropic medication (9.0%), herbal or vitamin products (8.2%), antibiotics (7.0%), gastrointestinal medications (6.8%) and topical products (6.6%). Forty per cent of callers enquired about multiple exposures. Conclusions: The utilisation of MotherSafe by consumers and general practitioners continues to increase, reflecting the strong demand for a teratogen counselling service that provides high-quality, evidence-based information on exposures during pregnancy and lactation. [source] | ||||||||||