780 research outputs found

    YY1 negatively regulates mouse myelin proteolipid protein (Plp1) gene expression in oligodendroglial cells

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    YY1 (Yin and Yang 1) is a multifunctional, ubiquitously expressed, zinc finger protein that can act as a transcriptional activator, repressor, or initiator element binding protein. Previous studies have shown that YY1 modulates the activity of reporter genes driven by the myelin PLP (proteolipid protein) (PLP1/Plp1) promoter. However, it is known that Plp1 intron 1 DNA contains regulatory elements that are required for the dramatic increase in gene activity, coincident with the active myelination period of CNS (central nervous system) development. The intron in mouse contains multiple prospective YY1 target sites including one within a positive regulatory module called the ASE (anti-silencer/enhancer) element. Results presented here demonstrate that YY1 has a negative effect on the activity of a Plp1-lacZ fusion gene [PLP(+)Z] in an immature oligodendroglial cell line (Oli-neu) that is mediated through sequences present in Plp1 intron 1 DNA. Yet YY1 does not bind to its alleged site in the ASE (even though the protein is capable of recognizing a target site in the promoter), indicating that the down-regulation of PLP(+)Z activity by YY1 in Oli-neu cells does not occur through a direct interaction of YY1 with the ASE sequence. Previous studies with Yy1 conditional knockout mice have demonstrated that YY1 is essential for the differentiation of oligodendrocyte progenitors. Nevertheless, the current study suggests that YY1 functions as a repressor (not an activator) of Plp1 gene expression in immature oligodendrocytes. Perhaps YY1 functions to keep the levels of PLP in check in immature cells before vast quantities of the protein are needed in mature myelinating oligodendrocytes

    Predatory Publishing: What You Don’t Know CAN Hurt You

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    Predatory publishers recruit faculty and graduate students to publish in their seemingly high quality journals that frequently lack peer review, charge fees, and have poor reputations. Tenure-track nursing faculty with publishing expectations may be especially vulnerable to the inviting emails received from predatory publishers. Nurse educators should collaborate with their health sciences librarians to identify and implement strategies to combat predatory publishers in nursing education and research

    Tunable magnetic exchange interactions in manganese-doped inverted core/shell ZnSe/CdSe nanocrystals

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    Magnetic doping of semiconductor nanostructures is actively pursued for applications in magnetic memory and spin-based electronics. Central to these efforts is a drive to control the interaction strength between carriers (electrons and holes) and the embedded magnetic atoms. In this respect, colloidal nanocrystal heterostructures provide great flexibility via growth-controlled `engineering' of electron and hole wavefunctions within individual nanocrystals. Here we demonstrate a widely tunable magnetic sp-d exchange interaction between electron-hole excitations (excitons) and paramagnetic manganese ions using `inverted' core-shell nanocrystals composed of Mn-doped ZnSe cores overcoated with undoped shells of narrower-gap CdSe. Magnetic circular dichroism studies reveal giant Zeeman spin splittings of the band-edge exciton that, surprisingly, are tunable in both magnitude and sign. Effective exciton g-factors are controllably tuned from -200 to +30 solely by increasing the CdSe shell thickness, demonstrating that strong quantum confinement and wavefunction engineering in heterostructured nanocrystal materials can be utilized to manipulate carrier-Mn wavefunction overlap and the sp-d exchange parameters themselves.Comment: To appear in Nature Materials; 18 pages, 4 figures + Supp. Inf

    Quantum Gravity: General Introduction and Recent Developments

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    I briefly review the current status of quantum gravity. After giving some general motivations for the need of such a theory, I discuss the main approaches in quantizing general relativity: Covariant approaches (perturbation theory, effective theory, and path integrals) and canonical approaches (quantum geometrodynamics, loop quantum gravity). I then address quantum gravitational aspects of string theory. This is followed by a discussion of black holes and quantum cosmology. I end with some remarks on the observational status of quantum gravity.Comment: 21 pages, 6 figures, invited contribution for "Annalen der Physik", v2: minor corrections, additional reference

    Metabolomics demonstrates divergent responses of two Eucalyptus species to water stress

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    Past studies of water stress in Eucalyptus spp. generally highlighted the role of fewer than five “important” metabolites, whereas recent metabolomic studies on other genera have shown tens of compounds are affected. There are currently no metabolite profiling data for responses of stress-tolerant species to water stress. We used GC–MS metabolite profiling to examine the response of leaf metabolites to a long (2 month) and severe (ιpredawn < −2 MPa) water stress in two species of the perennial tree genus Eucalyptus (the mesic Eucalyptus pauciflora and the semi-arid Eucalyptus dumosa). Polar metabolites in leaves were analysed by GC–MS and inorganic ions by capillary electrophoresis. Pressure–volume curves and metabolite measurements showed that water stress led to more negative osmotic potential and increased total osmotically active solutes in leaves of both species. Water stress affected around 30–40% of measured metabolites in E. dumosa and 10–15% in E. pauciflora. There were many metabolites that were affected in E. dumosa but not E. pauciflora, and some that had opposite responses in the two species. For example, in E. dumosa there were increases in five acyclic sugar alcohols and four low-abundance carbohydrates that were unaffected by water stress in E. pauciflora. Re-watering increased osmotic potential and decreased total osmotically active solutes in E. pauciflora, whereas in E. dumosa re-watering led to further decreases in osmotic potential and increases in total osmotically active solutes. This experiment has added several extra dimensions to previous targeted analyses of water stress responses in Eucalyptus, and highlights that even species that are closely related (e.g. congeners) may respond differently to water stress and re-waterin

    Developing a Standard Set of Patient-centred Outcomes for Adult Oral Health - An International, Cross-disciplinary Consensus.

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    OBJECTIVE: To develop a minimum Adult Oral Health Standard Set (AOHSS) for use in clinical practice, research, advocacy and population health. MATERIALS AND METHODS: An international oral health working group (OHWG) was established, of patient advocates, researchers, clinicians and public health experts to develop an AOHSS. PubMed was searched for oral health clinical and patient-reported measures and case-mix variables related to caries and periodontal disease. The selected patient-reported outcome measures focused on general oral health, and oral health-related quality of life tools. A consensus was reached via Delphi with parallel consultation of subject matter content experts. Finally, comments and input were elicited from oral health stakeholders globally, including patients/consumers. RESULTS: The literature search yielded 1,453 results. After inclusion/exclusion criteria, 959 abstracts generated potential outcomes and case-mix variables. Delphi rounds resulted in a consensus-based selection of 80 individual items capturing 31 outcome and case-mix concepts. Global reviews generated 347 responses from 87 countries, and the patient/consumer validation survey elicited 129 responses. This AOHSS includes 25 items directed towards patients (including demographics, the impact of their oral health on oral function, a record of pain and oral hygiene practices, and financial implications of care) and items for clinicians to complete, including medical history, a record of caries and periodontal disease activity, and types of dental treatment delivered. CONCLUSION: In conclusion, utilising a robust methodology, a standardised core set of oral health outcome measures for adults, with a particular emphasis on caries and periodontal disease, was developed
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