Neutron-proton effective mass splitting in neutron-rich matter at normal density from analyzing nucleon-nucleus scattering data within an isospin dependent optical model

The neutron-proton effective $k$-mass splitting in asymmetric nucleonic matter of isospin asymmetry $\delta$ and normal density is found to be $m^{*}_{n-p}\equiv(m^{*}_{n}-m^{*}_{p})/m=(0.41 \pm0.15)\delta$ from analyzing globally 1088 sets of reaction and angular differential cross sections of proton elastic scattering on 130 targets with beam energies from 0.783 MeV to 200 MeV, and 1161 sets of data of neutron elastic scattering on 104 targets with beam energies from 0.05 MeV to 200 MeV within an isospin dependent non-relativistic optical potential model. It sets a useful reference for testing model predictions on the momentum dependence of the nucleon isovector potential necessary for understanding novel structures and reactions of rare isotopes.Comment: Published version, Physics Letters B743 (2015) 40

Expanding accessibility of diagnostics through miniaturized technologies

There is a disproportionate burden of disease (measured in daily-adjusted life years, or DALYs) in low-income countries. Much of this disparity is due to infectious diseases: 53% of DALYs in Africa are due to infectious diseases, compared with only 3% in the American continents. This disparity is largely due to differences in electrical and transport infrastructure as well as access to skilled personnel and monetary resources. Current diagnostic solutions are primarily designed for high-resource settings and therefore these solutions cannot be easily translated to a lower-resource setting. In order to tackle this health disparity, new solutions must be designed specifically for a lower-resource setting. In this dissertation, we take a translational approach to engineering appropriate diagnostics for resource-limited settings. First, we develop a handheld smartphone accessory to perform an assay similar to enzyme-linked immunosorbent assay (ELISA), traditionally a laboratory-based test. In 15 minutes, it provides an objective diagnostic readout important for minimal training, while using an average of 1.6mW of power and costing only $34. We further develop the device to provide a quantitative hemoglobin measurement simultaneously with an HIV immunoassay, for use in antenatal care screening. The multiplexing two assay types that are clinically relevant has the potential to streamline workflow. While specifications can be demonstrated in the laboratory, the true test of the device must be performed in the field. We brought our smartphone accessory to three health centers in Kigali, Rwanda to be used by healthcare workers with no prior experience in ELISA. After a short 30 minute training, the healthcare workers were able to obtain diagnostic results comparable to other immunoassays run under field conditions. With a simple and user-friendly design, we sought to further expand the usage of our device as a self-testing device, having patients test themselves. Lastly, we explore manufacturable thermoplastics as a material for a microfluidic diagnostic for nucleic acid detection. The sum of this work aims to gain insight into methods of design, testing, and implementation of translational design

Probing nuclear symmetry energy at high densities using pion, kaon, eta and photon productions in heavy-ion collisions

The high-density behavior of nuclear symmetry energy is among the most uncertain properties of dense neutron-rich matter. Its accurate determination has significant ramifications in understanding not only the reaction dynamics of heavy-ion reactions especially those induced by radioactive beams but also many interesting phenomena in astrophysics, such as the explosion mechanism of supernova and the properties of neutron stars. The heavy-ion physics community has devoted much effort during the last few years to constrain the high-density symmetry using various probes. In particular, the pion-/pion+ ratio has been most extensively studied both theoretically and experimentally. All models have consistently predicted qualitatively that the pion-/pion+ ratio is a sensitive probe of the high-density symmetry energy especially with beam energies near the pion production threshold. However, the predicted values of the pion-/pion+ ratio are still quite model dependent mostly because of the complexity of modeling pion production and reabsorption dynamics in heavy-ion collisions, leading to currently still controversial conclusions regarding the high-density behavior of nuclear symmetry energy from comparing various model calculations with available experimental data. As more pion-/pion+ data become available and a deeper understanding about the pion dynamics in heavy-ion reactions is obtained, more penetrating probes, such as the kaon+/kaon0 ratio, eta meson and high energy photons are also being investigated or planned at several facilities. Here, we review some of our recent contributions to the community effort of constraining the high-density behavior of nuclear symmetry energy in heavy-ion collisions. In addition, the status of some worldwide experiments for studying the high-density symmetry energy, including the HIRFL-CSR external target experiment (CEE) are briefly introduced.Comment: 10 pages, 10 figures, Contribution to the Topical Issue on Nuclear Symmetry Energy in EPJA Special Volum

Bis(4-cyano-1-methyl­pyridinium) bis­(1,2-dicyano­ethene-1,2-dithiol­ato-κ2 S,S′)cuprate(II)

The title ion-pair compound, (C7H7N2)2[Cu(C4N2S2)2], was obtained by the direct reaction of CuCl2·2H2O, disodium maleonitrile­dithiol­ate (Na2mnt) and 4-cyano-1-methyl­pyridinium iodide. The anion and one pyridinium cation lie entirely on a mirror plane, whereas for the other cation, a crystallographic mirror plane runs through the N and para-C atoms of the pyridine ring, the methyl C atom, and the cyano group. In the crystal, ions are linked into a three-dimensional network by C—H⋯N hydrogen bonds

High-efficient screening method for identification of key genes in breast cancer through microarray and bioinformatics

Background/Aim: The aim of the present study was to identify key pathways and genes in breast cancer and develop a new method for screening key genes with abnormal expression based on bioinformatics. Materials and Methods: Three microarray datasets GSE21422, GSE42568 and GSE45827 were downloaded from the Gene Expression Omnibus (GEO) database and differentially expressed genes (DEGs) were analyzed using GEO2R. The gene ontology (GO) and pathway enrichment analysis were established through DAVID database. The protein–protein interaction (PPI) network was performed through the Search Tool for the Retrieval of Interacting Genes (STRING) database and managed by Cytoscape. The overall survival (OS) analysis of the 4 genes including AURKA, CDH1, CDK1 and PPARG that had higher degrees in this network was uncovered Kaplan-Meier analysis. Results: A total of 811 DEGs were identified in breast cancer, which were enriched in biological processes, including cell cycle, mitosis, vessel development and lipid metabolic. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the up-regulated DEGs were particularly involved in cell cycle, progesterone-mediated oocyte maturation and leukocyte transendothelial migration, while the down-regulated DEGs were mainly involved in regulation of lipolysis, fatty acid degradation and glycerolipid metabolism. Through PPI network analysis, 14 hub genes were identified. Among them, the high expression of AURKA, CDH1 and CDK1 were associated with worse OS of breast cancer patients; while the high expression of PPARG was linked with better OS. Conclusion: The present study identified key pathways and genes involved in breast cancer which are potential molecular targets for breast cancer treatment and diagnosis