409 research outputs found
Renormalization of the tunnel splitting in a rotating nanomagnet
We study spin tunneling in a magnetic nanoparticle with biaxial anisotropy
that is free to rotate about its anisotropy axis. Exact instanton of the
coupled equations of motion is found that connects degenerate classical energy
minima. We show that mechanical freedom of the particle renormalizes magnetic
anisotropy and increases the tunnel splitting.Comment: 4 pages, 3 figure
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Glucocorticoid-Induced TNF Receptor Family-Related Protein Ligand is Requisite for Optimal Functioning of Regulatory CD4+ T Cells
Glucocorticoid-induced tumor necrosis factor receptor family-related protein (TNFRSF18, CD357) is constitutively expressed on regulatory T cells (Tregs) and is inducible on effector T cells. In this report, we examine the role of glucocorticoid-induced TNF receptor family-related protein ligand (GITR-L), which is expressed by antigen presenting cells, on the development and expansion of Tregs. We found that GITR-L is dispensable for the development of naturally occurring FoxP3+ Treg cells in the thymus. However, the expansion of Treg in GITR-L−/− mice is impaired after injection of the dendritic cells (DCs) inducing factor Flt3 ligand. Furthermore, DCs from the liver of GITR-L−/− mice were less efficient in inducing proliferation of antigen-specific Treg cells in vitro than the same cells from WT littermates. Upon gene transfer of ovalbumin into hepatocytes of GITR-L−/−FoxP3(GFP) reporter mice using adeno-associated virus (AAV8-OVA) the number of antigen-specific Treg in liver and spleen is reduced. The reduced number of Tregs resulted in an increase in the number of ovalbumin specific CD8+ T effector cells. This is highly significant because proliferation of antigen-specific CD8+ cells itself is dependent on the presence of GITR-L, as shown by in vitro experiments and by adoptive transfers into GITR-L−/−Rag−/− and Rag−/− mice that had received AAV8-OVA. Surprisingly, administering αCD3 significantly reduced the numbers of FoxP3+ Treg cells in the liver and spleen of GITR-L−/− but not WT mice. Because soluble Fc-GITR-L partially rescues αCD3 induced in vitro depletion of the CD103+ subset of FoxP3+CD4+ Treg cells, we conclude that expression of GITR-L by antigen presenting cells is requisite for optimal Treg-mediated regulation of immune responses including those in response during gene transfer
The rarely heard voice: students with moderate general learning disability speak of their experiences in mainstream schools
Magnetic resonance (MR) imaging of vascular malformations
Vascular malformations pose a diagnostic and therapeutic challenge due to the broad differential diagnosis as well as common utilization of inadequate or inaccurate classification systems among healthcare providers. Therapeutic approaches to these lesions vary based on the type, size, and extent of the vascular anomaly, necessitating accurate diagnosis and classification. Magnetic resonance (MR) imaging (MRI) is an effective modality for classifying vascular anomalies due to its ability to delineate the extent and anatomic relationship of the malformation to adjacent structures. In addition to anatomical mapping, the complete evaluation of vascular anomalies includes hemodynamic characterization. Dynamic time-resolved contrast-enhanced MR angiography provides information regarding hemodynamics of vascular anomalies, differentiating high- and low-flow vascular malformations. Radiologists must identify the MRI features of vascular malformations for better diagnosis and classification
Isogonal non-crystallographic periodic graphs based on knotted sodalite cages
This work considers non-crystallographic periodic nets obtained from multiple identical copies of an underlying crystallographic net by adding or flipping edges so that the result is connected. Such a structure is called a `ladder' net here because the 1-periodic net shaped like an ordinary (infinite) ladder is a particularly simple example. It is shown how ladder nets with no added edges between layers can be generated from tangled polyhedra. These are simply related to the zeolite nets SOD, LTA and FAU. They are analyzed using new extensions of algorithms in the program Systre that allow unambiguous identification of locally stable ladder nets
Validation and robustness testing of a HPLC method for the determination of avermectins and moxidectin in animal liver samples using an alumina column clean-up
peer-reviewedA multi-residue method has been developed for the quantitative determination of moxidectin, abamectin, doramectin and ivermectin in liver samples, with capability for qualitative identification of the presence of eprinomectin. Liver samples are extracted with isooctane, followed by clean-up on alumina-N solid phase extraction (SPE) cartridges. Extracts are derivatised and determined by high-performance liquid chromatography (HPLC) with fluorescence detection. The method was validated using bovine liver fortified at levels of 4 and 20 μg kg−1 with the drugs. The mean recovery from bovine liver ranged between 90 and 96%. The intra and inter-assay variations showed RSD typically of <5% and <10%, respectively. The procedure was applied also to ovine and porcine liver, giving similar results. A robustness study, carried out on the alumina clean-up step, indicated that the step is relatively insensitive to method changes. However, significant differences overall were found for the type of alumina and/or commercial SPE cartridge used. The limit of quantitation of the method is 2 μg kg−1 (ppb)
Top 50 highly cited articles on dual energy computed tomography (DECT) in abdominal radiology : a bibliometric analysis
This study aims to identify the 50 most highly cited articles on dual energy computed tomography (DECT) in abdominal radiology. Thomson Reuters Web of Science All Databases was queried without year or language restriction. Only original research articles with a primary focus on abdominal radiology using DECT were selected. Review articles, meta-analyses, and studies without human subjects were excluded. Fifty articles with the highest average yearly citation were identified. These articles were published between 2007 and 2017 in 12 journals, with the most in Radiology (12 articles). Articles had a median of 7 authors, with all first authors but one primarily affiliated to radiology departments. The United States of America produced the most articles (16), followed by Germany (13 articles), and China (7 articles). Most studies used Dual Source DECT technology (35 articles), followed by Rapid Kilovoltage Switching (14 articles), and Sequential Scanning (1 article). The top three scanned organs were the liver (24%), kidney (16%), and urinary tract (15%). The most commonly studied pathology was urinary calculi (28%), renal lesion/tumor (23%), and hepatic lesion/tumor (20%). Our study identifies intellectual milestones in the applications of DECT in abdominal radiology. The diversity of the articles reflects on the characteristics and quality of the most influential publications related to DECT
Life in a Fishbowl: The evolution of the communication center as a sustainable component of institutional culture
In 2015, Kathleen Turner offered several benefits of Communication Center research and mentioned areas for future study. Turner (2015) believes that communication center directors would benefit from research that crosses institutional boundaries and contexts. Further, it is important that communication center directors demonstrate what clients have gained from the center. We must continue to recognize that “clients” are multi-faceted and our communication center spaces serve students, faculty, staff, administrators and the institution. Thus, this manuscript will, as Turner (2015) pleaded, help others think through how to “enhance their communication centers with clients, colleagues, and communities” (p. 3). Ultimately, it is important for center staff, as well as affiliated faculty and administrators, to concern ourselves with how the center integrates itself as part of the institution’s culture
Life in a Fishbowl: Student perception data for long-term center sustainability
Communication center directors, staff and tutors must continually analyze student perception of the center space in order to promote long-term campus viability. Thus, this manuscript addresses perceptions of communication center liberal arts students at a small, southern private university. Through surveys, students were asked how they utilize the communication center space, what projects they worked on as communication center participants, and improvement for the future. The measure for this study included a survey with questions that addressed Fishbowl use, technology or furniture use in the Fishbowl, the feedback process on student projects, and Fishbowl improvements. Situated learning theory is presented as a theoretical framework for communication center success and collaborative learning.
Development and optimisation of an improved derivatisation procedure for the determination of avermectins and milbemycins in bovine liver
peer-reviewedA robust procedure has been developed to overcome the instability problems experienced with the fluorescent
derivative of eprinomectin. The procedure involves addition of acetic acid, together with the typical reagents
methylimidazole and trifluoroacetic anhydride, to produce a fluorescent molecule that can be determined by high
performance liquid chromatography (HPLC) with fluorescence detection. Derivatisation is completed in 30 min at
65 °C. This derivatisation procedure was shown to be suitable, also, for the related compounds, moxidectin,
abamectin, doramectin and ivermectin. A multi-residue method for these compounds in bovine liver has been
developed using the derivatisation procedure. Samples are extracted with acetonitrile; followed by clean-up on
deactivated alumina and C18 solid phase extraction (SPE) cartridges. The method was validated using bovine liver
fortified at levels of 4 and 20 mg kg21 with the drugs. The mean recovery ranged between 73 and 97%. The intraand inter-assay variations showed relative standard deviations typically of < 6% and < 14%, respectively. The
limit of quantitation of the method is 2 mg kg21
(ppb)
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