2,611 research outputs found
Ab initio calculation of the anomalous Hall conductivity by Wannier interpolation
The intrinsic anomalous Hall effect in ferromagnets depends on subtle
spin-orbit-induced effects in the electronic structure, and recent ab-initio
studies found that it was necessary to sample the Brillouin zone at millions of
k-points to converge the calculation. We present an efficient first-principles
approach for computing the anomalous Hall conductivity. We start out by
performing a conventional electronic-structure calculation including spin-orbit
coupling on a uniform and relatively coarse k-point mesh. From the resulting
Bloch states, maximally-localized Wannier functions are constructed which
reproduce the ab-initio states up to the Fermi level. The Hamiltonian and
position-operator matrix elements, needed to represent the energy bands and
Berry curvatures, are then set up between the Wannier orbitals. This completes
the first stage of the calculation, whereby the low-energy ab-initio problem is
transformed into an effective tight-binding form. The second stage only
involves Fourier transforms and unitary transformations of the small matrices
set up in the first stage. With these inexpensive operations, the quantities of
interest are interpolated onto a dense k-point mesh and used to evaluate the
anomalous Hall conductivity as a Brillouin zone integral. The present scheme,
which also avoids the cumbersome summation over all unoccupied states in the
Kubo formula, is applied to bcc Fe, giving excellent agreement with
conventional, less efficient first-principles calculations. Remarkably, we find
that more than 99% of the effect can be recovered by keeping a set of terms
depending only on the Hamiltonian matrix elements, not on matrix elements of
the position operator.Comment: 16 pages, 7 figure
Rapid and Deep Remission Induced by Blinatumomab for CD19-Positive Chronic Myeloid Leukemia in Lymphoid Blast Phase
In summary, we show rapid and deep remission induced by blinatumomab in CD19(+) blast phase CML. Clinicians may consider the use of bispecific T-cell engager therapy as a bridge to transplant. Additional studies are needed before expanding the US Food and Drug Administration indication of blinatumomab to include lymphoid blast phase CML
Systematic screens of proteins binding to synthetic microRNA precursors
We describe a new, broadly applicable methodology for screening in parallel interactions of RNA-binding proteins (RBPs) with large numbers of microRNA (miRNA) precursors and for determining their affinities in native form in the presence of cellular factors. The assays aim at identifying pre-miRNAs that are potentially affected by the selected RBP during their biogenesis. The assays are carried out in microtiter plates and use chemiluminescent readouts. Detection of bound RBPs is achieved by protein or tag-specific antibodies allowing crude cell lysates to be used as a source of RBP. We selected 70 pre-miRNAs with phylogenetically conserved loop regions and 25 precursors of other well-characterized miRNAs for chemical synthesis in 3′-biotinylated form. An equivalent set in unmodified form served as inhibitors in affinity determinations. By testing three RBPs known to regulate miRNA biogenesis on this set of pre-miRNAs, we demonstrate that Lin28 and hnRNP A1 from cell lysates or as recombinant protein domains recognize preferentially precursors of the let-7 family, and that KSRP binds strongly to pre-miR-1-
Leucine Rich α-2 Glycoprotein: A Novel Neutrophil Granule Protein and Modulator of Myelopoiesis
Leucine-rich α2 glycoprotein (LRG1), a serum protein produced by hepatocytes, has been implicated in angiogenesis and tumor promotion. Our laboratory previously reported the expression of LRG1 in murine myeloid cell lines undergoing neutrophilic granulocyte differentiation. However, the presence of LRG1 in primary human neutrophils and a role for LRG1 in regulation of hematopoiesis have not been previously described. Here we show that LRG1 is packaged into the granule compartment of human neutrophils and secreted upon neutrophil activation to modulate the microenvironment. Using immunofluorescence microscopy and direct biochemical measurements, we demonstrate that LRG1 is present in the peroxidase-negative granules of human neutrophils. Exocytosis assays indicate that LRG1 is differentially glycosylated in neutrophils, and co-released with the secondary granule protein lactoferrin. Like LRG1 purified from human serum, LRG1 secreted from activated neutrophils also binds cytochrome c. We also show that LRG1 antagonizes the inhibitory effects of TGFβ1 on colony growth of human CD34+ cells and myeloid progenitors. Collectively, these data invoke an additional role for neutrophils in innate immunity that has not previously been reported, and suggest a novel mechanism whereby neutrophils may modulate the microenvironment via extracellular release of LRG1
Urologic practice patterns of pediatricians: a survey from a large multisite pediatric care center
ObjectiveTo evaluate the practice patterns of pediatricians as they relate to common urologic concerns.Materials and methodsAn anonymous 15-question survey was created and distributed to all pediatricians at our institution, a large multisite care center. This study was deemed exempt by the institutional review board.Results55 of the 122 (45%) providers queried responded. 93% of the participants were female, and 7.3% were male. 55% recommended testicular self-examination at adolescence, while 39% did not recommend at any age. 78% stated that they were “Fairly confident” in the exam for undescended testicle (UTD). One-third referred patients with UDT to a subspecialist upon recognition at birth, 13% at 3 months of age, and 28% at 6 months of age. 10% reported obtaining a VCUG after the first febrile urinary tract infection (UTI), 26% after the second, and 36% only if there were abnormal findings on renal ultrasound. 28% of providers reported that they refer to pediatric urology after the initial febrile UTI. 19% provided antibiotics for UTI symptoms alone with negative urinalysis and urine culture.ConclusionsDespite established guidelines, practice patterns varied among pediatricians. Pediatricians typically followed the AAP's guidelines regarding VCUGs (62%), with only a few adhering to urologic recommendations (9%). Despite the consistency between AAP and AUA guidelines regarding the age at which to refer a patient for cryptorchidism, about 70% of practitioners referred patients too early or too late. Harmonized, consolidated guidelines between pediatricians and pediatric urologists would improve patient care and efficiency of the healthcare system
A System for Performing High Throughput Assays of Synaptic Function
Unbiased, high-throughput screening has proven invaluable for dissecting complex biological processes. Application of this general approach to synaptic function would have a major impact on neuroscience research and drug discovery. However, existing techniques for studying synaptic physiology are labor intensive and low-throughput. Here, we describe a new high-throughput technology for performing assays of synaptic function in primary neurons cultured in microtiter plates. We show that this system can perform 96 synaptic vesicle cycling assays in parallel with high sensitivity, precision, uniformity, and reproducibility and can detect modulators of presynaptic function. By screening libraries of pharmacologically defined compounds on rat forebrain cultures, we have used this system to identify novel effects of compounds on specific aspects of presynaptic function. As a system for unbiased compound as well as genomic screening, this technology has significant applications for basic neuroscience research and for the discovery of novel, mechanism-based treatments for central nervous system disorders
Correction to: EGFR/Ras-induced CCL20 production modulates the tumour microenvironment
The article ‘EGFR/Ras-induced CCL20 production modulates the tumour microenvironment’, written by Andreas Hippe, Stephan Alexander Braun, Péter Oláh, Peter Arne Gerber, Anne Schorr, Stephan Seeliger, Stephanie Holtz, Katharina Jannasch, Andor Pivarcsi, Bettina Buhren, Holger Schrumpf, Andreas Kislat, Erich Bünemann, Martin Steinhoff, Jens Fischer, Sérgio A. Lira, Petra Boukamp, Peter Hevezi, Nikolas Hendrik Stoecklein, Thomas Hoffmann, Frauke Alves, Jonathan Sleeman, Thomas Bauer, Jörg Klufa, Nicole Amberg, Maria Sibilia, Albert Zlotnik, Anja Müller- Homey and Bernhard Homey, was originally published electronically on the publisher’s internet portal on 30 June 2020 without open access. With the author(s)’ decision to opt for Open Choice the copyright of the article changed on 16 September 2021 to © The Author(s) 2021 and the article is forthwith distributed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/ licenses/by/4.0/. Open Access funding enabled and organized by Projekt DEAL
NetMets: software for quantifying and visualizing errors in biological network segmentation
One of the major goals in biomedical image processing is accurate segmentation of networks embedded in volumetric data sets. Biological networks are composed of a meshwork of thin filaments that span large volumes of tissue. Examples of these structures include neurons and microvasculature, which can take the form of both hierarchical trees and fully connected networks, depending on the imaging modality and resolution. Network function depends on both the geometric structure and connectivity. Therefore, there is considerable demand for algorithms that segment biological networks embedded in three-dimensional data. While a large number of tracking and segmentation algorithms have been published, most of these do not generalize well across data sets. One of the major reasons for the lack of general-purpose algorithms is the limited availability of metrics that can be used to quantitatively compare their effectiveness against a pre-constructed ground-truth. In this paper, we propose a robust metric for measuring and visualizing the differences between network models. Our algorithm takes into account both geometry and connectivity to measure network similarity. These metrics are then mapped back onto an explicit model for visualization
COVID-19 Convalescent Plasma Therapy Decreases Inflammatory Cytokines: A Randomized Controlled Trial
This study examined the role that cytokines may have played in the beneficial outcomes found when outpatient individuals infected with SARS-CoV-2 were transfused with COVID-19 convalescent plasma (CCP) early in their infection. We found that the pro-inflammatory cytokine IL-6 decreased significantly faster in patients treated early with CCP. Participants with COVID-19 treated with CCP later in the infection did not have the same effect. This decrease in IL-6 levels after early CCP treatment suggests a possible role of inflammation in COVID-19 progression. The evidence of IL-6 involvement brings insight into the possible mechanisms involved in CCP treatment mitigating SARS-CoV-2 severity
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