12,974 research outputs found

    Temperature and light requirements for growth of two diatom species (Bacillariophyceae) isolated from an Arctic macroalga

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    In the present study, two abundant epiphyticdiatom taxa were isolated from the assimilation hairs ofthe brown macroalga Chordaria flagelliformis collected inthe Arctic Kongsfjorden (Spitsbergen, Norway), establishedas unialgal cultures and their growth rates determinedunder controlled photon fluence rate andtemperature conditions. Using morphological (light andscanning electron microscopy) and SSU rRNA gene databoth isolates (ROS D99 and ROS D125) were identifiedas members of a FragilariaSynedropsis clade. Themolecular data of ROS D99 and ROS D125 were notidentical to any other published sequence. While ROSD99 has been identified as Fragilaria barbararum mainlydue to the SEM characteristics, ROS D125 could not bedefinitely identified although morphological data speakfor Fragilaria striatula. Both diatom species showedsimilar growth rates at all temperatures and photon fluencerates tested. They grew well between 0 and 15Cwithoptimum temperatures of 1214C, but did not survive20C. Therefore, compared to Antarctic diatoms bothtaxa from Kongsfjorden can be characterised as eurythermalorganisms. Increasing photon fluence rates between2 and 15 lmol m2 s1 were accompanied with analmost twofold increase in growth rates, but photon fluencerates >15 lmol m2 s1 did not further enhancegrowth pointing to low light requirements. From thesedata optimum, minimum and maximum photon fluencerates and temperatures for growth can be assessed indicatingthat both diatoms are well acclimated to the fluctuatingenvironmental conditions in the Arctic habitat

    Triple Bars and Complex Central Structures in Disk Galaxies

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    We present an analysis of ground-based and HST images of three early-type barred galaxies. The first, NGC 2681, may be the clearest example yet of a galaxy with three concentric bars. The two other galaxies were previously suggested as triple-barred. Our analysis shows that while NGC 3945 is probably double-barred, NGC 4371 has only one bar; but both have intriguing central structures. NGC 3945 has a large, extremely bright disk inside its primary bar, with patchy dust lanes, a faint nuclear ring or pseudo-ring within the disk, and an apparent secondary bar crossing the ring. NGC 4371 has a bright nuclear ring only marginally bluer than the surrounding bulge and bar. There is no evidence for significant dust or star formation in either of these nuclear rings. The presence of stellar nuclear rings suggests that the centers of these galaxies are dynamically cool and disklike.Comment: LaTeX: 6 pages, 3 figures, uses emulateapj.sty. Accepted by Astrophysical Journal Letters. Version with full-resolution figures available at: http://www.astro.wisc.edu/~erwin/research

    Alcohol-Induced Histone Acetylation Reveals a Gene Network Involved in Alcohol Tolerance

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    Alfredo Ghezzi, Harish R. Krishnan, Linda Lew, Francisco J. Prado III, Darryl S. Ong, Nigel S. Atkinson, Section of Neurobiology and Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, United States of AmericaSustained or repeated exposure to sedating drugs, such as alcohol, triggers homeostatic adaptations in the brain that lead to the development of drug tolerance and dependence. These adaptations involve long-term changes in the transcription of drug-responsive genes as well as an epigenetic restructuring of chromosomal regions that is thought to signal and maintain the altered transcriptional state. Alcohol-induced epigenetic changes have been shown to be important in the long-term adaptation that leads to alcohol tolerance and dependence endophenotypes. A major constraint impeding progress is that alcohol produces a surfeit of changes in gene expression, most of which may not make any meaningful contribution to the ethanol response under study. Here we used a novel genomic epigenetic approach to find genes relevant for functional alcohol tolerance by exploiting the commonalities of two chemically distinct alcohols. In Drosophila melanogaster, ethanol and benzyl alcohol induce mutual cross-tolerance, indicating that they share a common mechanism for producing tolerance. We surveyed the genome-wide changes in histone acetylation that occur in response to these drugs. Each drug induces modifications in a large number of genes. The genes that respond similarly to either treatment, however, represent a subgroup enriched for genes important for the common tolerance response. Genes were functionally tested for behavioral tolerance to the sedative effects of ethanol and benzyl alcohol using mutant and inducible RNAi stocks. We identified a network of genes that are essential for the development of tolerance to sedation by alcohol.This work was supported by National Institute of Health grant R01 AA018037 to NSA (http://www.nih.gov/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.NeuroscienceWaggoner Center for Alcohol and Addiction ResearchEmail: [email protected] (AG)Email: [email protected] (NSA

    Physical therapy and deep brain stimulation in Parkinson’s Disease: Protocol for a pilot randomized controlled trial

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    Abstract Background Subthalamic nucleus deep brain stimulation (STN-DBS) reduces tremor, muscle stiffness, and bradykinesia in people with Parkinson’s Disease (PD). Walking speed, known to be reduced in PD, typically improves after surgery; however, other important aspects of gait may not improve. Furthermore, balance may worsen and falls may increase after STN-DBS. Thus, interventions to improve balance and gait could reduce morbidity and improve quality of life following STN-DBS. Physical therapy (PT) effectively improves balance and gait in people with PD, but studies on the effects of PT have not been extended to those treated with STN-DBS. As such, the efficacy, safety, and feasibility of PT in this population remain to be determined. The purpose of this pilot study is to address these unmet needs. We hypothesize that PT designed to target balance and gait impairment will be effective, safe, and feasible in this population. Methods/design Participants with PD treated with STN-DBS will be randomly assigned to either a PT or control group. Participants assigned to PT will complete an 8-week, twice-weekly PT program consisting of exercises designed to improve balance and gait. Control group participants will receive the current standard of care following STN-DBS, which does not include prescription of PT. The primary aim is to assess preliminary efficacy of PT on balance (Balance Evaluation Systems Test). A secondary aim is to assess efficacy of PT on gait (GAITRite instrumented walkway). Participants will be assessed OFF medication/OFF stimulation and ON medication/ON stimulation at baseline and at 8 and 12 weeks after baseline. Adverse events will be measured over the duration of the study, and adherence to PT will be measured to determine feasibility. Discussion To our knowledge, this will be the first study to explore the preliminary efficacy, safety, and feasibility of PT for individuals with PD with STN-DBS. If the study suggests potential efficacy, then this would justify larger trials to test effectiveness and safety of PT for those with PD with STN-DBS. Trial registration NCT03181282 (clinicaltrials.gov). Registered on 7 June 2017

    In vitro and in vivo studies of the trypanocidal properties of WRR-483 against Trypanosoma cruzi.

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    BackgroundCruzain, the major cysteine protease of Trypanosoma cruzi, is an essential enzyme for the parasite life cycle and has been validated as a viable target to treat Chagas' disease. As a proof-of-concept, K11777, a potent inhibitor of cruzain, was found to effectively eliminate T. cruzi infection and is currently a clinical candidate for treatment of Chagas' disease.Methodology/principal findingsWRR-483, an analog of K11777, was synthesized and evaluated as an inhibitor of cruzain and against T. cruzi proliferation in cell culture. This compound demonstrates good potency against cruzain with sensitivity to pH conditions and high efficacy in the cell culture assay. Furthermore, WRR-483 also eradicates parasite infection in a mouse model of acute Chagas' disease. To determine the atomic-level details of the inhibitor interacting with cruzain, a 1.5 A crystal structure of the protease in complex with WRR-483 was solved. The structure illustrates that WRR-483 binds covalently to the active site cysteine of the protease in a similar manner as other vinyl sulfone-based inhibitors. Details of the critical interactions within the specificity binding pocket are also reported.ConclusionsWe demonstrate that WRR-483 is an effective cysteine protease inhibitor with trypanocidal activity in cell culture and animal model with comparable efficacy to K11777. Crystallographic evidence confirms that the mode of action is by targeting the active site of cruzain. Taken together, these results suggest that WRR-483 has potential to be developed as a treatment for Chagas' disease

    Effectiveness of prenatal teaching on prevention of breast engorgement

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    Background: Breast engorgement is a major issue in the early postpartum period under the influence of hormonal shift and increase milk production. The purpose of this study was to evaluate the prevention, recognition and management of breast engorgement.Methods: Quasi Experimental, quantitative study conducted in AIMS, Kochi among sixty mothers by Convenience sampling technique. The design used was pre-test post-test control group design. A semi structured knowledge questionnaire, Bristol Breastfeeding Assessment Tool and an Observational checklist were used to collect the data. Prenatal teaching provided to the Experimental group.Results: The mean pre-test knowledge level of control group was 9.83 and the post-test knowledge was 10.03. In the Experimental group, the mean pre-test level was 10.20 and the post-test level is 20.76. The ‘t’ value of control group was 0.71 and that of Experimental group was 12.83 which was highly significant at 0.001 level. There was a significant increase in knowledge score in Experimental group. Comparing the breastfeeding practices regarding positioning and attachment in both groups, showed a significant difference at the level of 0.001 but other two aspects, sucking and swallowing were not significant. Comparing the incidence, 13.3% mothers reported in experimental group whereas 63.3% in the control group, which showed a remarkable decrease in the incidence of breast engorgement in the former group.Conclusions: The prenatal teaching was effective in improving the health of mothers as well as practices of breastfeeding and it helped in reduction of the incidence of breast engorgement

    Penerapan Strategi Pembelajaran Aktif Kartu Arisan untuk Meningkatkan Prestasi Belajar Siswa pada Pokok Bahasan Koloid di Kelas XI IPA SMA Negeri 9 Pekanbaru

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    Active learning strategy of arisan card to improve student learning achievement in class XI IPA SMAN 9 Pekanbaru has done. The research is a kind of experiment research with pretest-posttest design. The samples of this research were the students of group XI IPA3 as the experimental group and students of group XI IPA1 as the control group. Experimental group is a group that is applied to active learning strategy of arisan card while the control group was not. Strategy of arisan card is a strategy that uses the principles of arisan, where there is a question card and an answer card . Cards are in the matter of the roll to be drawn and the card answers have been given to students in groups randomly. Data analysis technique used is the t-test. Based on data analysis of data obtained tcount> ttable is 3,22>1.67, means that the application of active learning strategy of arisan card can improve student learning achievement on the topic of colloid in class XI IPA SMAN 9 Pekanbaru. The category improvement of student achievement at experiment group was high category with N-gain normalized is 0,80
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