1,206 research outputs found

    Ultrasound imaging in teaching cardiac physiology.

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    This laboratory session provides hands-on experience for students to visualize the beating human heart with ultrasound imaging. Simple views are obtained from which students can directly measure important cardiac dimensions in systole and diastole. This allows students to derive, from first principles, important measures of cardiac function, such as stroke volume, ejection fraction, and cardiac output. By repeating the measurements from a subject after a brief exercise period, an increase in stroke volume and ejection fraction are easily demonstrable, potentially with or without an increase in left ventricular end-diastolic volume (which indicates preload). Thus, factors that affect cardiac performance can readily be discussed. This activity may be performed as a practical demonstration and visualized using an overhead projector or networked computers, concentrating on using the ultrasound images to teach basic physiological principles. This has proved to be highly popular with students, who reported a significant improvement in their understanding of Frank-Starling's law of the heart with ultrasound imaging. </jats:p

    Why, what, and how? case study on law, risk, and decision making as necessary themes in built environment teaching

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    The paper considers (and defends) the necessity of including legal studies as a core part of built environment undergraduate and postgraduate curricula. The writer reflects upon his own experience as a lawyer working alongside and advising built environment professionals in complex land remediation and site safety management situations in the United Kingdom and explains how themes of liability, risk, and decision making can be integrated into a practical simulation in order to underpin more traditional lecture-based law teaching. Through reflection upon the writer's experiments with simulation-based teaching, the paper suggests some innovations that may better orientate law teaching to engage these themes and, thereby, enhance the relevance of law studies to the future needs of built environment professionals in practice.</p

    Gal4 turnover and transcription activation

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    Growing evidence supports the notion that proteasome-mediated destruction of transcriptional activators can be intimately coupled to their function. Recently, Nalley et al. challenged this view by reporting that the prototypical yeast activator Gal4 does not dynamically associate with chromatin, but rather 'locks in' to stable promoter complexes that are resistant to competition. Here we present evidence that the assay used to reach this conclusion is unsuitable, and that promoter-bound, active Gal4 is indeed susceptible to competition in vivo. Our data challenge the key evidence that Nalley et al. used to reach their conclusion, and indicate that Gal4 functions in vivo within the context of dynamic promoter complexes

    Flower senescence in composite flowers, can understanding how dahlia florets senesce help to increase dahlia vase life?

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    The dahlia is popular as an ornamental garden plant in the UK, however, its value as a cut flower has been undermined by its short vase life. The vase life of dahlias is often no more than 5 days, whereas 10-14 days are required by the cut flower industry due to the supply chain involved in transporting cut flowers from growers to retailers, sufficient time in store, and still guaranteeing 5 days vase life to a consumer. The current study has considered ethylene sensitivity and how phytohormones interact with one another during the senescence process. In conjunction with these traditional methods, RNA sequencing and de novo assembly of the dahlia transcriptome in the cultivar 'Sylvia' has been carried out, resulting in an assembly of over 20,000 genes, many of which change in expression during floret senescence

    Deepening democracy within Ireland's social partnership

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    Ireland's social partnership process, now under attack from a number of quarters, has repeatedly been charged with being 'undemocratic' in that it undermines the sovereign position of elected political representatives, with key policy formulation and decision-making taking place in fora outside the institutions of representative democracy. These critiques echo those against new forms of networked governance more globally. A key question therefore is how (and if) democracy may be deepened within social partnership or its potential successor(s). This article addresses this question by employing a post-liberal democratic framework to examine social partnership in practice, and by drawing lessons from another partnership process, Malawi's PRSP. Drawing from Malawi's experience, it is argued that democracy can be deepened within social partnership when governance deliberations and negotiations are conducted under conditions of vibrant public debate and genuine perspective-based representation, and when the communicative and discursive norms are widened to allow for such representation

    Artemin, a Novel Member of the GDNF Ligand Family, Supports Peripheral and Central Neurons and Signals through the GFRα3–RET Receptor Complex

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    AbstractThe glial cell line–derived neurotrophic factor (GDNF) ligands (GDNF, Neurturin [NTN], and Persephin [PSP]) signal through a multicomponent receptor system composed of a high-affinity binding component (GFRα1–GFRα4) and a common signaling component (RET). Here, we report the identification of Artemin, a novel member of the GDNF family, and demonstrate that it is the ligand for the former orphan receptor GFRα3–RET. Artemin is a survival factor for sensory and sympathetic neurons in culture, and its expression pattern suggests that it also influences these neurons in vivo. Artemin can also activate the GFRα1–RET complex and supports the survival of dopaminergic midbrain neurons in culture, indicating that like GDNF (GFRα1–RET) and NTN (GFRα2–RET), Artemin has a preferred receptor (GFRα3–RET) but that alternative receptor interactions also occur

    A compendium and functional characterization of mammalian genes involved in adaptation to Arctic or Antarctic environments

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    Many mammals are well adapted to surviving in extremely cold environments. These species have likely accumulated genetic changes that help them efficiently cope with low temperatures. It is not known whether the same genes related to cold adaptation in one species would be under selection in another species. The aims of this study therefore were: to create a compendium of mammalian genes related to adaptations to a low temperature environment; to identify genes related to cold tolerance that have been subjected to independent positive selection in several species; to determine promising candidate genes/pathways/organs for further empirical research on cold adaptation in mammals

    A Conditional Yeast E1 Mutant Blocks the Ubiquitin–Proteasome Pathway and Reveals a Role for Ubiquitin Conjugates in Targeting Rad23 to the Proteasome

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    E1 ubiquitin activating enzyme catalyzes the initial step in all ubiquitin-dependent processes. We report the isolation of uba1-204, a temperature-sensitive allele of the essential Saccharomyces cerevisiae E1 gene, UBA1. Uba1-204 cells exhibit dramatic inhibition of the ubiquitin–proteasome system, resulting in rapid depletion of cellular ubiquitin conjugates and stabilization of multiple substrates. We have employed the tight phenotype of this mutant to investigate the role ubiquitin conjugates play in the dynamic interaction of the UbL/UBA adaptor proteins Rad23 and Dsk2 with the proteasome. Although proteasomes purified from mutant cells are intact and proteolytically active, they are depleted of ubiquitin conjugates, Rad23, and Dsk2. Binding of Rad23 to these proteasomes in vitro is enhanced by addition of either free or substrate-linked ubiquitin chains. Moreover, association of Rad23 with proteasomes in mutant and wild-type cells is improved upon stabilizing ubiquitin conjugates with proteasome inhibitor. We propose that recognition of polyubiquitin chains by Rad23 promotes its shuttling to the proteasome in vivo

    A genome-wide scan for common alleles affecting risk for autism

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    Although autism spectrum disorders (ASDs) have a substantial genetic basis, most of the known genetic risk has been traced to rare variants, principally copy number variants (CNVs). To identify common risk variation, the Autism Genome Project (AGP) Consortium genotyped 1558 rigorously defined ASD families for 1 million single-nucleotide polymorphisms (SNPs) and analyzed these SNP genotypes for association with ASD. In one of four primary association analyses, the association signal for marker rs4141463, located within MACROD2, crossed the genome-wide association significance threshold of P < 5 × 10−8. When a smaller replication sample was analyzed, the risk allele at rs4141463 was again over-transmitted; yet, consistent with the winner's curse, its effect size in the replication sample was much smaller; and, for the combined samples, the association signal barely fell below the P < 5 × 10−8 threshold. Exploratory analyses of phenotypic subtypes yielded no significant associations after correction for multiple testing. They did, however, yield strong signals within several genes, KIAA0564, PLD5, POU6F2, ST8SIA2 and TAF1C
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