4,141 research outputs found
Object-oriented construction of a multigrid electronic-structure code with Fortran 90
We describe the object-oriented implementation of a higher-order
finite-difference density-functional code in Fortran 90. Object-oriented models
of grid and related objects are constructed and employed for the implementation
of an efficient one-way multigrid method we have recently proposed for the
density-functional electronic-structure calculations. Detailed analysis of
performance and strategy of the one-way multigrid scheme will be presented.Comment: 24 pages, 6 figures, to appear in Comput. Phys. Com
Tgif1 Counterbalances The Activity Of Core Pluripotency Factors In Mouse Embryonic Stem Cells
Core pluripotency factors, such as Oct4, Sox2, and Nanog, play important roles in maintaining embryonic stem cell (ESC) identity by autoregulatory feedforward loops. Nevertheless, the mechanism that provides precise control of the levels of the ESC core factors without indefinite amplification has remained elusive. Here, we report the direct repression of core pluripotency factors by Tgif1, a previously known terminal repressor of TGF beta/activin/nodal signaling. Overexpression of Tgif1 reduces the levels of ESC core factors, whereas its depletion leads to the induction of the pluripotency factors. We confirm the existence of physical associations between Tgif1 and Oct4, Nanog, and HDAC1/2 and further show the level of Tgif1 is not significantly altered by treatment with an activator/inhibitor of the TGF beta/activin/nodal signaling. Collectively, our findings establish Tgif1 as an integral member of the core regulatory circuitry of mouse ESCs that counterbalances the levels of the core pluripotency factors in a TGF beta/activin/nodal-independent manner.Cancer Prevention Research Institute of Texas (CPRIT) R1106Molecular Bioscience
Estimation of an Examinee's Ability in the Web-Based Computerized Adaptive Testing Program IRT-CAT
We developed a program to estimate an examinee s ability in order to provide freely available access to a web-based computerized adaptive testing (CAT) program. We used PHP and Java Script as the program languages, PostgresSQL as the database management system on an Apache web server and Linux as the operating system. A system which allows for user input and searching within inputted items and creates tests was constructed. We performed an ability estimation on each test based on a Rasch model and 2- or 3-parametric logistic models. Our system provides an algorithm for a web-based CAT, replacing previous personal computer-based ones, and makes it possible to estimate an examinee's ability immediately at the end of test
Optimization of coupling between photonic crystal resonator and curved microfiber
The evanescent coupling from a photonic crystal resonator to a micron-thick
optical fiber is investigated in detail by using a 3D-FDTD method. Properly
designed photonic crystal cavity and taper structures are proposed, and optimal
operating conditions are found to enhance the coupling strength while
suppressing other cavity losses including the coupling to the slab propagating
mode and to the higher-order fiber mode. In simulation, the coupling into the
fundamental fiber mode is discriminated from other cavity losses by spatial and
parity filtering of the FDTD results. The coupling efficiency of more than 80%
into the fundamental fiber mode together with a total Q factor of 5,200 is
achieved for the fiber diameter of 1.0 um and the air gap of 200 nm between the
fiber and the cavity.Comment: 6 pages, 6 figure
Superconducting transition of a two-dimensional Josephson junction array in weak magnetic fields
The superconducting transition of a two-dimensional (2D) Josephson junction
array exposed to weak magnetic fields has been studied experimentally.
Resistance measurements reveal a superconducting-resistive phase boundary in
serious disagreement with the theoretical and numerical expectations. Critical
scaling analyses of the characteristics indicate contrary to the
expectations that the superconducting-to-resistive transition in weak magnetic
fields is associated with a melting transition of magnetic-field-induced
vortices directly from a pinned-solid phase to a liquid phase. The expected
depinning transition of vortices from a pinned-solid phase to an intermediate
floating-solid phase was not observed. We discuss effects of the
disorder-induced random pinning potential on phase transitions of vortices in a
2D Josephson junction array.Comment: 9 pages, 7 figures (EPS+JPG format), RevTeX
Current status of the predicted satellite imagery generation in NMSC/KMA
Póster presentado en: 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019
CD9 may contribute to the survival of human germinal center B cells by facilitating the interaction with follicular dendritic cells
AbstractThe germinal center (GC) is a dynamic microenvironment where antigen (Ag)-activated B cells rapidly expand and differentiate, generating plasma cells (PC) that produce high-affinity antibodies. Precise regulation of survival and proliferation of Ag-activated B cells within the GC is crucial for humoral immune responses. The follicular dendritic cells (FDC) are the specialized stromal cells in the GC that prevent apoptosis of GC-B cells. Recently, we reported that human GC-B cells consist of CD9+ and CD9− populations and that it is the CD9+ cells that are committed to the PC lineage. In this study, we investigated the functional role of CD9 on GC-B cells. Tonsillar tissue section staining revealed that in vivo CD9+ GC-B cells localized in the light zone FDC area. Consistent this, in vitro CD9+ GC-B cells survived better than CD9− GC-B cells in the presence of HK cells, an FDC line, in a cell–cell contact-dependent manner. The frozen tonsillar tissue section binding assay showed that CD9+ GC-B cells bound to the GC area of tonsillar tissues significantly more than the CD9− GC-B cells did and that the binding was significantly inhibited by neutralizing anti-integrin β1 antibody. Furthermore, CD9+ cells bound to soluble VCAM-1 more than CD9− cells did, resulting in activation and stabilization of the active epitope of integrin β1. All together, our data suggest that CD9 on GC-B cells contributes to survival by strengthening their binding to FDC through the VLA4/VCAM-1 axis
SSASS: Semi-Supervised Approach for Stenosis Segmentation
Coronary artery stenosis is a critical health risk, and its precise
identification in Coronary Angiography (CAG) can significantly aid medical
practitioners in accurately evaluating the severity of a patient's condition.
The complexity of coronary artery structures combined with the inherent noise
in X-ray images poses a considerable challenge to this task. To tackle these
obstacles, we introduce a semi-supervised approach for cardiovascular stenosis
segmentation. Our strategy begins with data augmentation, specifically tailored
to replicate the structural characteristics of coronary arteries. We then apply
a pseudo-label-based semi-supervised learning technique that leverages the data
generated through our augmentation process. Impressively, our approach
demonstrated an exceptional performance in the Automatic Region-based Coronary
Artery Disease diagnostics using x-ray angiography imagEs (ARCADE) Stenosis
Detection Algorithm challenge by utilizing a single model instead of relying on
an ensemble of multiple models. This success emphasizes our method's capability
and efficiency in providing an automated solution for accurately assessing
stenosis severity from medical imaging data.Comment: MICCAI 2023 Conference ARCADE Challeng
MPSeg : Multi-Phase strategy for coronary artery Segmentation
Accurate segmentation of coronary arteries is a pivotal process in assessing
cardiovascular diseases. However, the intricate structure of the cardiovascular
system presents significant challenges for automatic segmentation, especially
when utilizing methodologies like the SYNTAX Score, which relies extensively on
detailed structural information for precise risk stratification. To address
these difficulties and cater to this need, we present MPSeg, an innovative
multi-phase strategy designed for coronary artery segmentation. Our approach
specifically accommodates these structural complexities and adheres to the
principles of the SYNTAX Score. Initially, our method segregates vessels into
two categories based on their unique morphological characteristics: Left
Coronary Artery (LCA) and Right Coronary Artery (RCA). Specialized ensemble
models are then deployed for each category to execute the challenging
segmentation task. Due to LCA's higher complexity over RCA, a refinement model
is utilized to scrutinize and correct initial class predictions on segmented
areas. Notably, our approach demonstrated exceptional effectiveness when
evaluated in the Automatic Region-based Coronary Artery Disease diagnostics
using x-ray angiography imagEs (ARCADE) Segmentation Detection Algorithm
challenge at MICCAI 2023.Comment: MICCAI 2023 Conference ARCADE Challeng
- …