107 research outputs found

    Modified locus equations categorize stop place in a perceptually realistic time frame

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    This is the publisher's version, also available electronically from http://scitation.aip.org/content/asa/journal/jasa/131/6/10.1121/1.4722169.Slope and y-intercepts of locus equations have previously been shown to successfully classify place of articulation for English voiced stop consonants when derived from measurements at vowel onset and vowel midpoint. However, listeners are capable of identifying English voiced stops when less than 30 ms of vowel is presented. The present results show that modified locus equation measurements made within the first several pitch periods of a vowel following an English voiced stop were also successful at classifying place of articulation, consistent with the amount of vocalic information necessary for perceptual identification of English voiced stops /b d g/

    Computational Model Prediction and Biological Validation Using Simplified Mixed Field Exposures for the Development of a GCR Reference Field

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    The yield of chromosomal aberrations has been shown to increase in the lymphocytes of astronauts after long-duration missions of several months in space. Chromosome exchanges, especially translocations, are positively correlated with many cancers and are therefore a potential biomarker of cancer risk associated with radiation exposure. Although extensive studies have been carried out on the induction of chromosomal aberrations by low- and high-LET radiation in human lymphocytes, fibroblasts, and epithelial cells exposed in vitro, there is a lack of data on chromosome aberrations induced by low dose-rate chronic exposure and mixed field beams such as those expected in space. Chromosome aberration studies at NSRL will provide the biological validation needed to extend the computational models over a broader range of experimental conditions (more complicated mixed fields leading up to the galactic cosmic rays (GCR) simulator), helping to reduce uncertainties in radiation quality effects and dose-rate dependence in cancer risk models. These models can then be used to answer some of the open questions regarding requirements for a full GCR reference field, including particle type and number, energy, dose rate, and delivery order. In this study, we designed a simplified mixed field beam with a combination of proton, helium, oxygen, and iron ions with shielding or proton, helium, oxygen, and titanium without shielding. Human fibroblasts cells were irradiated with these mixed field beam as well as each single beam with acute and chronic dose rate, and chromosome aberrations (CA) were measured with 3-color fluorescent in situ hybridization (FISH) chromosome painting methods. Frequency and type of CA induced with acute dose rate and chronic dose rates with single and mixed field beam will be discussed. A computational chromosome and radiation-induced DNA damage model, BDSTRACKS (Biological Damage by Stochastic Tracks), was updated to simulate various types of CA induced by acute exposures of the mixed field beams used for the experiments. The chromosomes were simulated by a polymer random walk algorithm with restrictions to their respective domains in the nucleus [1]. The stochastic dose to the nucleus was calculated with the code RITRACKS [2]. Irradiation of a target volume by a mixed field of ions was implemented within RITRACKs, and the fields of ions can be delivered over specific periods of time, allowing the simulation of dose-rate effects. Similarly, particles of various types and energies extracted from a pre-calculated spectra of galactic cosmic rays (GCR) can be used in RITRACKS. The number and spatial location of DSBs (DNA double-strand breaks) were calculated in BDSTRACKS using the simulated chromosomes and local (voxel) dose. Assuming that DSBs led to chromosome breaks, and simulating the rejoining of damaged chromosomes occurring during repair, BDSTRACKS produces the yield of various types of chromosome aberrations as a function of time (only final yields are presented). A comparison between experimental and simulation results will be shown

    Multifocal electroretinogram and Optical Coherence tomography spectral-domain in arc welding macular injury: a case report

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    <p>Abstract</p> <p>Background</p> <p>the purpose of this study was to report a binocular photic retinal injury induced by plasma arc welding and the follow-up after treatment with vitamin supplements for a month. In our study, we used different diagnostic tools such as fluorescein angiography (FA), optical coherence tomography (OCT) and multifocal electroretinogram (mfERG).</p> <p>Case presentation</p> <p>in the first visit after five days from arc welding injury in the left eye (LE) the visual acuity was 0.9 and 1.0 in the right eye (RE). FA was normal in both eyes. OCT in the left eye showed normal profile and normal reflectivity and one month later, a hyperreflectivity appeared in the external limiting membrane (ELM). The mfERG signal in the LE was 102.30 nV/deg2 five days after the injury and 112.62 nV/deg2 after one month and in the RE respectively 142.70 nV/deg2 and 159.46 nV/deg2.</p> <p>Conclusions</p> <p>in cases of retinal photo injury it is important for the ophthalmologist to evaluate tests such as OCT and the mfERG in the diagnosis and follow-up of the patient because the recovery of visual acuity cannot exclude the persistence of phototoxic damage charged to the complex inner-outer segment of photoreceptors.</p

    Toxicological aspects of the use of phenolic compounds in disease prevention

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    The consumption of a diet low in fat and enhanced by fruits and vegetables, especially rich in phenolic compounds, may reduce risks of many civilization diseases. The use of traditional medicines, mainly derived from plant sources, has become an attractive segment in the management of many lifestyle diseases. Concerning the application of dietary supplements (based on phenolic compounds) in common practice, the ongoing debate over possible adverse effects of certain nutrients and dosage levels is of great importance. Since dietary supplements are not classified as drugs, their potential toxicities and interactions have not been thoroughly evaluated. First, this review will introduce phenolic compounds as natural substances beneficial for human health. Second, the potential dual mode of action of flavonoids will be outlined. Third, potential deleterious impacts of phenolic compounds utilization will be discussed: pro-oxidant and estrogenic activities, cancerogenic potential, cytotoxic effects, apoptosis induction and flavonoid-drug interaction. Finally, future trends within the research field will be indicated

    Medulloblastoma in childhood: revisiting intrathecal therapy in infants and children

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    Silk Roads ", a highway of migrations in Eurasia. New prospects from bioarcheology and paleoecology

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    Silk Roads connected China, Far East, Middle East and Europe during several millennia. Besides goods and material, people, animal and plants were constantly moving along a large geographic space that is Eurasia. This information can be found in European, Arab, Persian and Chinese historical sources as well as archaeological investigations. In fact, bioarcheological and paleoecological studies in Central Asia (including archaeozoology, archaeobotany, paleogenetics) published during the last decades have refined our understanding about the trajectories of diffusion of human communities along with several botanical and faunal taxa (including parasites, fruits, domestic pigs, chicken, camels and horses) and how these have impacted the peopling of Central Asia as well as its economies and landscapes. These “biological” mobilities and connectivity in Eurasia together with the spread of technologies and know-hows are partly at the origin of the emergence of the globalization. Climate change (particularly during the Holocene), on varying time scales, and the various phases of aridification or, on the contrary, humidification of Central Asia, are also at the heart of studies that attempt to measure the impact on human and non-human migrations and on interactions between nomads and sedentary people (sharing and conflict over water resources; development of new agricultural and livestock practices, etc.). Furthermore, studies focus on the modalities of diffusion of migratory movements, within crossroads zones (oases) or along land and river routes. In-turn, the development of continental-scale "biological" mobilities have also risen new ecological challenges and risks for territories (erosion of the biodiversity, overuse of water, desertification, etc.) and communities (e.g. traditional knowledge losses) at the local scale.https://prospectives21.sciencesconf.org/browse/session?sessionid=6385
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