479 research outputs found
Photorefractive incoherent-to-coherent optical converter
Photorefractive materials have been extensively used in
recent years as real-time recording media for optical holography.(^1,2) One prospective application of real-time holography is in the area of optical information processing; for example, the correlation between two mutually incoherent images has recently been demonstrated in real time in a four-wave mixing
geometry. (^3) Often, however, the information to be processed exists only in incoherent form. High performance spatial light modulators(^4) are thus necessary in many optical information processing systems to convert incoherent images to coherent replicas for subsequent processing. We report in this Communication the successful demonstration of real-time incoherent-to-coherent images transduction through the use of holographic recording in photorefractive crystals. Several possible configurations and experimental results are presented
Comparative Analysis Of Zebrafish And Planarian Model Systems For Developmental Neurotoxicity Screens Using An 87-Compound Library
There is a clear need to establish and validate new methodologies to more quickly and efficiently screen chemicals for potential toxic effects, particularly on development. The emergence of alternative animal systems for rapid toxicology screens presents valuable opportunities to evaluate how systems complement each other. In this article, we compare a chemical library of 87-compounds in two such systems, developing zebrafish and freshwater planarians, by screening for developmental neurotoxic effects. We show that the systems’ toxicological profiles are complementary to each other, with zebrafish yielding more detailed morphological endpoints and planarians more behavioral endpoints. Overall, zebrafish was more sensitive to this chemical library, yielding 86/87 hits, compared to 50/87 hits in planarians. The difference in sensitivity could not be attributed to molecular weight, Log Kow or the bioconcentration factor. Of the 87 chemicals, 28 had previously been evaluated in mammalian developmental neuro- (DNT), neuro- or developmental toxicity studies. Of the 28, 20 were hits in the planarian, and 27 were hits in zebrafish. Eighteen of the 28 had previously been identified as DNT hits in mammals and were highly associated with activity in zebrafish and planarian behavioral assays in this study. Only 1 chemical (out of 28) was a false negative in both zebrafish and planarian systems. Differences in endpoint coverage and system sensitivity illustrate the value of a dual systems approach to rapidly query a large chemical-bioactivity space and provide weight-of-evidence for prioritization of chemicals for further testing
Новий навчальний посібник “Україна в міжнародних організаціях”
Рецензія на посібник: Макар Ю. І. Україна в міжнародних організаціях : навч. посібник /
Ю. І. Макар, Б. П. Гдичинський, В. Ю. Макар, С. Д. Попик, Н. Ю. Ротар ; за ред. Ю. І. Макара. – Чернівці : Прут, 2009. – 880 с
High speed techniques for synthetic aperture radar image formation
One possible approach to high speed synthetic aperture radar signal reconstruction involves the utilization of two dimensional real time spatial light modulators as recyclable replacements for photographic film in the input transducer plane of a modified synthetic aperture radar (SAR) coherent optical processor. Leading candidate spatial light modulators include modified Pockels readout optical modulators (PROM), charge coupled devices (CCD) addressed liquid crystal light valves, and CCD addressed membrane light modulators. The fundamental physical limitations affecting SAR processor performance characteristics of such real time devices are under investigation. Current research on PROM is focused on the effects of device operatonal mode, device constitutive parameters, electro-optic crystal orientation, writing wavelength, frame rate/data overwrite/presuming, erasure completeness, and image retention on the overall quality of SAR image formation. Both modulated laser scanning and intensified CRT temporal to spatial input approaches are being examined
Early quantitative coronary angiography of saphenous vein grafts for coronary artery bypass grafting harvested by means of open versus endoscopic saphenectomy: a prospective randomized trial
AbstractObjectiveEndoscopic saphenectomy is associated with a decreased incidence of wound complications without an increase in histologic trauma or endothelial dysfunction in published reports. Concern remains about the patency of saphenous vein grafts harvested endoscopically and the development of early intimal hyperplasia. The purpose of this study was to compare early quantitative coronary analysis of saphenous vein grafts used for coronary artery bypass grafting harvested with the open versus endoscopic techniques.MethodsForty patients undergoing primary coronary artery bypass grafting surgery with at least 1 saphenous vein graft were randomized preoperatively to open versus endoscopic saphenectomy with bipolar cauterization of side branches. Quantitative coronary angiography was performed a mean of 3 months (range, 1-9 months) after the operation.ResultsThere was no statistically significant difference in the patency rates of internal thoracic artery grafts between the open and endoscopic groups and no statistically significant difference in the patency rates of saphenous vein grafts between both groups (85.2% vs 84.4%, P = .991). Quantitative coronary angiography showed no difference in graft stenosis (≥50% of the internal diameter of the graft) in the body of the saphenous vein grafts in the open versus endoscopic saphenectomy groups (3.7% vs 0%, P = .280).ConclusionAngiographic appearance and patency rates of saphenous vein grafts harvested with the endoscopic technique are similar to those of saphenous vein grafts harvested with the open technique. These results support the use of endoscopic saphenectomy because of the known lower incidence of wound and infectious complications and superior functional results
Key Issues in the Modes of Action and Effects of Trichloroethylene Metabolites for Liver and Kidney Tumorigenesis
Trichloroethylene (TCE) exposure has been associated with increased risk of liver and kidney cancer in both laboratory animal and epidemiologic studies. The U.S. Environmental Protection Agency 2001 draft TCE risk assessment concluded that it is difficult to determine which TCE metabolites may be responsible for these effects, the key events involved in their modes of action (MOAs), and the relevance of these MOAs to humans. In this article, which is part of a mini-monograph on key issues in the health risk assessment of TCE, we present a review of recently published scientific literature examining the effects of TCE metabolites in the context of the preceding questions. Studies of the TCE metabolites dichloroacetic acid (DCA), trichloroacetic acid (TCA), and chloral hydrate suggest that both DCA and TCA are involved in TCE-induced liver tumorigenesis and that many DCA effects are consistent with conditions that increase the risk of liver cancer in humans. Studies of S-(1,2-dichlorovinyl)-l-cysteine have revealed a number of different possible cell signaling effects that may be related to kidney tumorigenesis at lower concentrations than those leading to cytotoxicity. Recent studies of trichloroethanol exploring an alternative hypothesis for kidney tumorigenesis have failed to establish the formation of formate as a key event for TCE-induced kidney tumors. Overall, although MOAs and key events for TCE-induced liver and kidney tumors have yet to be definitively established, these results support the likelihood that toxicity is due to multiple metabolites through several MOAs, none of which appear to be irrelevant to humans
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Aerobic Bioremediation of PAH Contaminated Soil Results in Increased Genotoxicity and Developmental Toxicity
This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Chemical Society and can be found at: https://doi.org/10.1021/acs.est.5b00499The formation of more polar and toxic polycyclic aromatic hydrocarbon (PAH)
transformation products is one of the concerns associated with the bioremediation of PAH-contaminated soils. Soil contaminated with coal tar (pre-bioremediation) from a former
manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (post-bioremediation) and extracted using pressurized liquid extraction. The soil extracts were
fractionated, based on polarity, and analyzed for 88 PAHs (unsubstituted, oxygenated, nitrated,
and heterocyclic PAHs). The PAH concentrations in the soil tested, post-bioremediation, were
lower than their regulatory maximum allowable concentrations (MACs), with the exception of
the higher molecular weight PAHs (BaA, BkF, BbF, BaP, and IcdP), most of which did not
undergo significant biodegradation. The soil extract fractions were tested for genotoxicity using the DT40 chicken lymphocyte bioassay and developmental toxicity using the embryonic
zebrafish (Danio rerio) bioassay. A statistically significant increase in genotoxicity was
measured in the unfractionated soil extract, as well as in four polar soil extract fractions, post-bioremediation (p < 0.05). In addition, a statistically significant increase in developmental
toxicity was measured in one polar soil extract fraction, post-bioremediation (p < 0.05). A series
of morphological abnormalities, including peculiar caudal fin malformations and
hyperpigmentation in the tail, were measured in several soil extract fractions in embryonic
zebrafish, both pre- and post-bioremediation. The increased toxicity measured post-bioremediation is not likely due to the 88 PAHs measured in this study (including quinones), because most were not present in the toxic polar fractions and/or because their concentrations did not increase post-bioremediation. However, the increased toxicity measured post-bioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs (PHE, 1MPHE, 2MPHE, PRY, BaA, and FLA) that were most degraded
External validation of a predictive model of survival after cytoreductive nephrectomy for metastatic renal cell carcinoma.
INTRODUCTION: Recent trials have emphasized the importance of a precise patient selection for cytoreductive nephrectomy (CN). In 2013, a nomogram was developed for pre- and postoperative prediction of the probability of death (PoD) after CN in patients with metastatic renal cell carcinoma. To date, the single-institutional nomogram which included mostly patients from the cytokine era has not been externally validated. Our objective is to validate the predictive model in contemporary patients in the targeted therapy era. METHODS: Multi-institutional European and North American data from patients who underwent CN between 2006 and 2013 were used for external validation. Variables evaluated included preoperative serum albumin and lactate dehydrogenase levels, intraoperative blood transfusions (yes/no) and postoperative pathologic stage (primary tumour and nodes). In addition, patient characteristics and MSKCC risk factors were collected. Using the original calibration indices and quantiles of the distribution of predictions, Kaplan-Meier estimates and calibration plots of observed versus predicted PoD were calculated. For the preoperative model a decision curve analysis (DCA) was performed. RESULTS: Of 1108 patients [median OS of 27 months (95% CI 24.6-29.4)], 536 and 469 patients had full data for the validation of the pre- and postoperative models, respectively. The AUC for the pre- and postoperative model was 0.68 (95% CI 0.62-0.74) and 0.73 (95% CI 0.68-0.78), respectively. In the DCA the preoperative model performs well within threshold survival probabilities of 20-50%. Most important limitation was the retrospective collection of this external validation dataset. CONCLUSIONS: In this external validation, the pre- and postoperative nomograms predicting PoD following CN were well calibrated. Although performance of the preoperative nomogram was lower than in the internal validation, it retains the ability to predict early death after CN
Antidepressants use during pregnancy and child psychomotor, cognitive and language development at 2 years of age—Results from the 3D Cohort Study
Introduction: Approximately 5.5% of pregnant women take antidepressants. Studies on prenatal exposure to antidepressants reported no association with child cognition, and inconsistent results with motor function and language development. A limitation has been the failure to adjust for prenatal maternal distress.Objectives: Assess the associations between prenatal exposure to antidepressants and child development at age two, while adjusting for maternal depressive symptoms and stress during pregnancy. Explore indirect effects through birth complications and consider sex-specific associations.Methods: This is an ancillary study of the 3D (Design Develop, Discover) Study initiated during pregnancy. Data on antidepressants were collected through medication logs spanning the entire pregnancy. Depressive symptoms and stress were assessed during pregnancy by self-reported questionnaires, motor and cognitive development with the Bayley Scales of Infant and Toddler Development (BSID-III), and language development with the MacArthur Communicative Development Inventories at age 2. Multiple linear regressions were used to assess the associations between exposure and developmental outcomes. Mediation models were used to assess indirect effects. Interaction terms were introduced to assess sex-specific associations.Results: 1,489 mother-child dyads were included, of whom 61 (4.1%) reported prenatal antidepressant use. Prenatal exposure was negatively associated with motor development (B = −0.91, 95% CI -1.73, −0.09 for fine motor, B = −0.89, 95% CI -1.81, 0.02 for gross motor), but not with cognitive (B = −0.53, 95% CI -1.82, 0.72) and language (B = 4.13, 95% CI -3.72, 11.89) development. Adjusting for maternal prenatal distress only slightly modified these associations. No indirect effect or differential effect according to child sex were found.Conclusion: This study supports evidence of a negative association between prenatal exposure to antidepressants and motor development at age two, after adjusting for maternal distress, but the effect size remains very small, with about only one BSID-III point lower in average
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