1,501 research outputs found

    Hydrothermal Growth of Heterogeneous Single Crystals for Solid State Laser Applications

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    Disclosed are heterogeneous crystals for use in a laser cavity and methods of forming the crystals. A crystal can be a monolithic crystal containing regions that are based upon the same host material but differ from one another according to some material feature such that they can perform various functions related to lasing. Disclosed methods include hydrothermal growth techniques for the growth of differing epitaxial layers on a host. A host material can be doped in one region with a suitable active lasing ion and can be formed with another region that is undoped and can act as an endcap, a waveguide cladding layer, or a substrate to provide strength and/or contact to a heat sink. Regions can be formed with controlled thickness in conjunction. Following formation, a heterogeneous crystal can be cut, polished and coated with mirror films at each end for use in a laser cavity

    Served Through Service: Undergraduate Students’ Experiences in Community Engaged Learning at a Catholic and Marianist University

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    Students participating in sustained community service at an urban Catholic and Marianist university were volunteer informants in this qualitative exploration of the meaning they make of their service experiences. A PhD student research team (nine members) interviewed fourteen undergraduate students (eleven of whom were seniors). Findings were organized as themes constructed within three domains: background, experience, and meaning. Within “background,” students who had prior work in faith-based service before college deepened their meaning of service. Within “experience,” there were social and cultural dynamics of navigating on and off campus life, including the roles students played as well as the challenge of time management. Within “meaning,” building relationships was central to community service. Students built strong personal relationships with and deep commitments to city residents; the meaning of their own identities grew and developed. Experiencing the roots of social injustice led students both to confirm and to reconsider their life vocations

    Served Through Service: Undergraduate Students’ Experiences in Community Engaged Learning at a Catholic and Marianist University

    Get PDF
    Students participating in sustained community service at an urban Catholic and Marianist university were volunteer informants in this qualitative exploration of the meaning they make of their service experiences. A PhD student research team (nine members) interviewed fourteen undergraduate students (eleven of whom were seniors). Findings were organized as themes constructed within three domains: background, experience, and meaning. Within “background,” students who had prior work in faith-based service before college deepened their meaning of service. Within “experience,” there were social and cultural dynamics of navigating on and off campus life, including the roles students played as well as the challenge of time management. Within “meaning,” building relationships was central to community service. Students built strong personal relationships with and deep commitments to city residents; the meaning of their own identities grew and developed. Experiencing the roots of social injustice led students both to confirm and to reconsider their life vocations. Estudiantes que participaban en servicios continuados a la comunidad en una universidad católica marianista urbana participaron como encuestados voluntarios de esta exploración cualitativa del significado que le dan a sus experiencias de servicio. Un equipo de investigación de estudiantes (nueve) de doctorado entrevistaron a catorce estudiantes de licenciatura (de los cuales 10 eran de último curso). Los resultados se organizaron en temas englobados en tres dominios: antecedentes, experiencia y significado. En “antecedentes”, los estudiantes que habían realizado trabajo previo en servicios religiosos antes de la universidad profundizaron su significado de servicio. Dentro de “experiencia”, hubo dinámicas sociales y culturales que navegaban dentro y fuera de la vida en el campus, desde el papel de los estudiantes hasta el reto de la gestión del tiempo. En “significado”, la construcción de relaciones resultó central para los servicios a la comunidad. Los estudiantes cultivaron fuertes relaciones personales y compromisos profundos con los residentes de la ciudad. El significado de su propia identidad creció y se desarrolló. Experimentar las raíces de la injusticia social orientó a los estudiantes a confirmar y reconsiderar su vocación y elección de vida. Palabras clave: servicio, aprendizaje a través del servicio, aprendizaje-servicio, aprendizaje comprometido con la comunidad, liderazgo estudiantil, estudiante de licenciatur

    Placental adaptations in growth restriction

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    The placenta is the primary interface between the fetus and mother and plays an important role in maintaining fetal development and growth by facilitating the transfer of substrates and participating in modulating the maternal immune response to prevent immunological rejection of the conceptus. The major substrates required for fetal growth include oxygen, glucose, amino acids and fatty acids, and their transport processes depend on morphological characteristics of the placenta, such as placental size, morphology, blood flow and vascularity. Other factors including insulin-like growth factors, apoptosis, autophagy and glucocorticoid exposure also affect placental growth and substrate transport capacity. Intrauterine growth restriction (IUGR) is often a consequence of insufficiency, and is associated with a high incidence of perinatal morbidity and mortality, as well as increased risk of cardiovascular and metabolic diseases in later life. Several different experimental methods have been used to induce placental insufficiency and IUGR in animal models and a range of factors that regulate placental growth and substrate transport capacity have been demonstrated. While no model system completely recapitulates human IUGR, these animal models allow us to carefully dissect cellular and molecular mechanisms to improve our understanding and facilitate development of therapeutic interventions

    The importance of quantum decoherence in brain processes

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    Based on a calculation of neural decoherence rates, we argue that that the degrees of freedom of the human brain that relate to cognitive processes should be thought of as a classical rather than quantum system, i.e., that there is nothing fundamentally wrong with the current classical approach to neural network simulations. We find that the decoherence timescales ~10^{-13}-10^{-20} seconds are typically much shorter than the relevant dynamical timescales (~0.001-0.1 seconds), both for regular neuron firing and for kink-like polarization excitations in microtubules. This conclusion disagrees with suggestions by Penrose and others that the brain acts as a quantum computer, and that quantum coherence is related to consciousness in a fundamental way.Comment: Minor changes to match accepted PRE version. 15 pages with 5 figs included. Color figures and links at http://www.physics.upenn.edu/~max/brain.html or from [email protected]. Physical Review E, in pres

    Gene expression allelic imbalance in ovine brown adipose tissue impacts energy homeostasis

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    Heritable trait variation within a population of organisms is largely governed by DNA variations that impact gene transcription and protein function. Identifying genetic variants that affect complex functional traits is a primary aim of population genetics studies, especially in the context of human disease and agricultural production traits. The identification of alleles directly altering mRNA expression and thereby biological function is challenging due to difficulty in isolating direct effects of cis-acting genetic variations from indirect trans-acting genetic effects. Allele specific gene expression or allelic imbalance in gene expression (AI) occurring at heterozygous loci provides an opportunity to identify genes directly impacted by cis-acting genetic variants as indirect trans-acting effects equally impact the expression of both alleles. However, the identification of genes showing AI in the context of the expression of all genes remains a challenge due to a variety of technical and statistical issues. The current study focuses on the discovery of genes showing AI using single nucleotide polymorphisms as allelic reporters. By developing a computational and statistical process that addressed multiple analytical challenges, we ranked 5,809 genes for evidence of AI using RNA-Seq data derived from brown adipose tissue samples from a cohort of late gestation fetal lambs and then identified a conservative subgroup of 1,293 genes. Thus, AI was extensive, representing approximately 25% of the tested genes. Genes associated with AI were enriched for multiple Gene Ontology (GO) terms relating to lipid metabolism, mitochondrial function and the extracellular matrix. These functions suggest that cis-acting genetic variations causing AI in the population are preferentially impacting genes involved in energy homeostasis and tissue remodelling. These functions may contribute to production traits likely to be under genetic selection in the population.Shila Ghazanfar, Tony Vuocolo, Janna L. Morrison, Lisa M. Nicholas, Isabella C. McMillen, Jean Y. H. Yang, ... et al

    Lrp1 is essential for lethal Rift Valley fever hepatic disease in mice

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    Rift Valley fever virus (RVFV) is an emerging arbovirus found in Africa. While RVFV is pantropic and infects many cells and tissues, viral replication and necrosis within the liver play a critical role in mediating severe disease. The low-density lipoprotein receptor-related protein 1 (Lrp1) is a recently identified host factor for cellular entry and infection by RVFV. The biological significance of Lrp1, including its role in hepatic disease in vivo, however, remains to be determined. Because Lrp1 has a high expression level in hepatocytes, we developed a mouse model in which Lrp1 is specifically deleted in hepatocytes to test how the absence of liver Lrp1 expression affects RVF pathogenesis. Mice lacking Lrp1 expression in hepatocytes showed minimal RVFV replication in the liver, longer time to death, and altered clinical signs toward neurological disease. In contrast, RVFV infection levels in other tissues showed no difference between the two genotypes. Therefore, Lrp1 is essential for RVF hepatic disease in mice

    The periconceptional environment and cardiovascular disease: does in vitro embryo culture and transfer influence cardiovascular development and health?

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    Assisted Reproductive Technologies (ARTs) have revolutionised reproductive medicine; however, reports assessing the effects of ARTs have raised concerns about the immediate and long-term health outcomes of the children conceived through ARTs. ARTs include manipulations during the periconceptional period, which coincides with an environmentally sensitive period of gamete/embryo development and as such may alter cardiovascular development and health of the offspring in postnatal life. In order to identify the association between ARTs and cardiovascular health outcomes, it is important to understand the events that occur during the periconceptional period and how they are affected by procedures involved in ARTs. This review will highlight the emerging evidence implicating adverse cardiovascular outcomes before and after birth in offspring conceived through ARTs in both human and animal studies. In addition, it will identify the potential underlying causes and molecular mechanisms responsible for the congenital and adult cardiovascular dysfunctions in offspring whom were conceived through ARTs.Monalisa Padhee, Song Zhang, Shervi Lie, Kimberley C. Wang, Kimberley J. Botting, I. Caroline McMillen, Severence M. MacLaughlin and Janna L. Morriso

    Exposure to rosiglitazone, a PPAR-gamma agonist, in late gestation reduces the abundance of factors regulating cardiac metabolism and cardiomyocyte size in the sheep fetus

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    It is unknown whether cardiomyocyte hypertrophy and the transition to fatty acid oxidation as the main source of energy after birth is dependent on the maturation of the cardiomyocytes' metabolic system, or on the limitation of substrate availability before birth. This study aimed to investigate whether intrafetal administration of a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, rosiglitazone, during late gestation can stimulate the expression of factors regulating cardiac growth and metabolism in preparation for birth, and the consequences of cardiac contractility in the fetal sheep at ∼140 days gestation. The mRNA expression and protein abundance of key factors regulating growth and metabolism were quantified using quantitative RT-PCR and Western blot analysis, respectively. Cardiac contractility was determined by measuring the Ca(2+) sensitivity and maximum Ca(2+)-activated force of skinned cardiomyocyte bundles. Rosiglitazone-treated fetuses had a lower cardiac abundance of insulin-signaling molecules, including insulin receptor-β, insulin receptor substrate-1 (IRS-1), phospho-IRS-1 (Tyr-895), phosphatidylinositol 3-kinase (PI3K) regulatory subunit p85, PI3K catalytic subunit p110α, phospho-3-phosphoinositide-dependent protein kinase 1 (Ser-241), protein kinase B (Akt-1), phospho-Akt (Ser-273), PKCζ, phospho-PKCζ(Thr-410), Akt substrate 160 kDa (AS160), phospho-AS160 (Thr-642), and glucose transporter type-4. Additionally, cardiac abundance of regulators of fatty acid β-oxidation, including adiponectin receptor 1, AMPKα, phospho-AMPKα (Thr-172), phospho-acetyl CoA carboxylase (Ser-79), carnitine palmitoyltransferase-1, and PGC-1α was lower in the rosiglitazone-treated group. Rosiglitazone administration also resulted in a decrease in cardiomyocyte size. Rosiglitazone administration in the late-gestation sheep fetus resulted in a decreased abundance of factors regulating cardiac glucose uptake, fatty acid β-oxidation, and cardiomyocyte size. These findings suggest that activation of PPAR-γ using rosiglitazone does not promote the maturation of cardiomyocytes; rather, it may decrease cardiac metabolism and compromise cardiac health later in life.Shervi Lie, Melisa Hui, I. Caroline McMillen, Beverly S. Muhlhausler, Giuseppe S. Posterino, Stacey L. Dunn, Kimberley C. Wang, Kimberley J. Botting, Janna L. Morriso
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