82 research outputs found

    The Effects of UV Exposure on the Antioxidant Enzyme Systems of Anemones

    Get PDF
    Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) which are housekeeping enzymes protect cells from harmful side effects of reactive oxygen species (ROS). Anemonia sulcata var. smaragdina andAnemonia rustica are widely distributed along the Turkish coastlines of Aegean Sea. Recent studies showed that the environmental stresses such as elevated temperature, ultraviolet light, pathogen infection and decreased salinity might cause well known bleaching effects in Anemonia species. The effect of UV-light on antioxidant enzyme activities such as SOD, CAT, GSH-Px, protein levels and secondary pigments were determined in A. sulcata var. smaragdina and A. rustica. SOD, CAT, GSH-Px activities, protein levels and secondary pigments of these morphotypes were observed in both tentacles and columns separately. According to studies on bleaching, the elevated UV radiation may cause this bleaching event as a stress factor. However, in the present study no bleaching event was observed in anemone samples even they are exposed to 5 hours UV-exposure. Moreover, UV exposure did not change antioxidant systems remarkably. However, many investigations are still needed for obtaining the complete picture of the effects of UV-light on cellular pathways of cnidarian–algal symbiosis

    Detection of subclinical keratoconus using biometric parameters

    Get PDF
    The validation of innovative methodologies for diagnosing keratoconus in its earliest stages is of major interest in ophthalmology. So far, subclinical keratoconus diagnosis has been made by combining several clinical criteria that allowed the definition of indices and decision trees, which proved to be valuable diagnostic tools. However, further improvements need to be made in order to reduce the risk of ectasia in patients who undergo corneal refractive surgery. The purpose of this work is to report a new subclinical keratoconus detection method based in the analysis of certain biometric parameters extracted from a custom 3D corneal model. This retrospective study includes two groups: the first composed of 67 patients with healthy eyes and normal vision, and the second composed of 24 patients with subclinical keratoconus and normal vision as well. The proposed detection method generates a 3D custom corneal model using computer-aided graphic design (CAGD) tools and corneal surfaces’ data provided by a corneal tomographer. Defined bio-geometric parameters are then derived from the model, and statistically analysed to detect any minimal corneal deformation. The metric which showed the highest area under the receiver-operator curve (ROC) was the posterior apex deviation. This new method detected differences between healthy and sub-clinical keratoconus corneas by using abnormal corneal topography and normal spectacle corrected vision, enabling an integrated tool that facilitates an easier diagnosis and follow-up of keratoconus.This publication has been carried out in the framework of the Thematic Network for Co-Operative Research in Health (RETICS) reference number RD16/0008/0012 financed by the Carlos III Health Institute-General Subdirection of Networks and Cooperative Investigation Centers (R&D&I National Plan 2013–2016) and the European Regional Development Fund (FEDER)

    Improving precision for detecting change in the shape of the cornea in patients with keratoconus

    Get PDF
    To investigate a method for precision analysis to discriminate true corneal change from measurement imprecision in keratoconus (KC). Thirty patients with KC and 30 healthy controls were included. Coefficients of repeatability and limits of agreement (LOA) were compared using multiple measurements for inter-observer and inter-device agreement with the Pentacam HR, Orbscan IIz, and Tomey Casia SS-1000. Correlation of repeated measurements was evaluated using a linear mixed effect model (also called random effect model). A formula was derived for the theoretical expected change in precision and compared with measured change. Correlation between measurements from the same eye was small (R = 0.13). The 99.73% LOA (3 SD) of the mean of three measurements, provided better precision than 95% LOA (2 SD) of single cut-off values as expected from statistical theory for uncorrelated measurements for evidence of a significant change in corneal shape in patients with keratoconus. This enabled the determination of cut-off values for the detection of true change in corneal shape. The mean of three repeated measurements will provide better precision when there is minimal correlation. Three (rather than two) standard deviations provides a precise estimate of the LOA within or between observers and can be used as a reliable measure for identifying stage-independent corneal shape changes (progression) in keratoconus

    Effects of Glyphosate and its Formulation, Roundup, on Reproduction in Zebrafish (Danio rerio)

    Get PDF
    This is an open access article that is freely available in ORE or from the publisher's web site. Please cite the published version.Copyright © 2014 American Chemical SocietyRoundup and its active ingredient glyphosate are among the most widely used herbicides worldwide and may contaminate surface waters. Research suggests both Roundup and glyphosate induce oxidative stress in fish and may also cause reproductive toxicity in mammalian systems. We aimed to investigate the reproductive effects of Roundup and glyphosate in fish and the potential associated mechanisms of toxicity. To do this, we conducted a 21-day exposure of breeding zebrafish (Danio rerio) to 0.01, 0.5, and 10 mg/L (glyphosate acid equivalent) Roundup and 10 mg/L glyphosate. 10 mg/L glyphosate reduced egg production but not fertilization rate in breeding colonies. Both 10 mg/L Roundup and glyphosate increased early stage embryo mortalities and premature hatching. However, exposure during embryogenesis alone did not increase embryo mortality, suggesting that this effect was caused primarily by exposure during gametogenesis. Transcript profiling of the gonads revealed 10 mg/L Roundup and glyphosate induced changes in the expression of cyp19a1 and esr1 in the ovary and hsd3b2, cat, and sod1 in the testis. Our results demonstrate that these chemicals cause reproductive toxicity in zebrafish, although only at high concentrations unlikely to occur in the environment, and likely mechanisms of toxicity include disruption of the steroidogenic biosynthesis pathway and oxidative stress.Natural Environment Research Counci

    Comparative effect of interactive mobiles (clickers) and communicative approach on the learning outcomes of the educationally disadvantaged Nigerian pupils in ESL classrooms

    Get PDF
    Effective teaching that promotes learners’ active engagement and the development of communicative proficiency has been a challenge to teachers of English as a second language (ESL). Previous research on second language (L2) teaching has shown that L2 learners improve better in communicative skills when they are actively engaged, participate in communicative tasks that facilitate interaction and are provided with the opportunity to use the target language in the classroom. This study focuses on improving ESL learners’ learning outcomes in remotely-located primary schools in Nigeria. The study aimed to test whether the introduction of Personal Response System (PRS) and communicative approach can improve pupils’ English-language communicative competences and their attitudes towards English learning. Specifically, this study examined the extent to which significant differences exist in pupils’ communicative competence performance scores and learning gains based on teachers’ use of a communicative approach, PRS and lecture methods in the ESL classroom. Furthermore, the research also attempted to find out whether pupils’ attitudes towards the learning of English would significantly differ based on teaching strategy. Attitudes of pupils and teachers towards the interventions were also investigated. A pre-test and post-test non-randomised control group design was adopted in this study. Some qualitative data were also collected to augment the quantitative main data. Ninety nine pupils from three intact classes in different schools in Ijebu-North local government, Ogun-State, Nigeria were assigned to two experimental groups and one control group. In addition to the traditional use of textbooks, one of the experimental groups was taught using communicative activities, while the second experimental group experienced communicative tasks blended with the use of a personal response system. The control group received the conventional classroom instruction (lecture method), including the use of the English language textbook. In order to provide answers to the research questions and the hypothesis of this study, English Language Listening Tests and English Language Speaking Tests, Pupils’ Attitude to English Language Lesson Questionnaire, Pupils’ Attitude to Clickers’ Questionnaire and Pupils’ Attitude to Communicative Approach Questionnaire were administered at the pre-and post-test stages of the research. These instruments were also complemented with data from classroom observation, video recording of the instructional process, and audio-recorded interviews with the teachers and selected pupils in the experimental groups. The results indicate that the two experimental groups showed greater improvement in communicative competence than did the control group; but the PRS group improved more than the communicative approach group both in listening and speaking skills development. Moreover, pupils’ learning gains were statistically different, with the PRS group having the highest gain scores above the communicative approach group, while the control group did not experience increased learning gains. The results also reveal pupils’ mixed-reactions with respect to their attitudes toward the English language lesson and the interventions. Teachers’ attitudes toward the interventions were in the positive direction

    cGMP-Dependent Protein Kinase Type I Is Implicated in the Regulation of the Timing and Quality of Sleep and Wakefulness

    Get PDF
    Many effects of nitric oxide (NO) are mediated by the activation of guanylyl cyclases and subsequent production of the second messenger cyclic guanosine-3â€Č,5â€Č-monophosphate (cGMP). cGMP activates cGMP-dependent protein kinases (PRKGs), which can therefore be considered downstream effectors of NO signaling. Since NO is thought to be involved in the regulation of both sleep and circadian rhythms, we analyzed these two processes in mice deficient for cGMP-dependent protein kinase type I (PRKG1) in the brain. Prkg1 mutant mice showed a strikingly altered distribution of sleep and wakefulness over the 24 hours of a day as well as reductions in rapid-eye-movement sleep (REMS) duration and in non-REM sleep (NREMS) consolidation, and their ability to sustain waking episodes was compromised. Furthermore, they displayed a drastic decrease in electroencephalogram (EEG) power in the delta frequency range (1–4 Hz) under baseline conditions, which could be normalized after sleep deprivation. In line with the re-distribution of sleep and wakefulness, the analysis of wheel-running and drinking activity revealed more rest bouts during the activity phase and a higher percentage of daytime activity in mutant animals. No changes were observed in internal period length and phase-shifting properties of the circadian clock while chi-squared periodogram amplitude was significantly reduced, hinting at a less robust oscillator. These results indicate that PRKG1 might be involved in the stabilization and output strength of the circadian oscillator in mice. Moreover, PRKG1 deficiency results in an aberrant pattern, and consequently a reduced quality, of sleep and wakefulness, possibly due to a decreased wake-promoting output of the circadian system impinging upon sleep
    • 

    corecore