RESUMEN
BACKGROUND: The Office of Naval Research (ONR) organized a STEM Challenge initiative to explore how intelligent tutoring systems (ITSs) can be developed in a reasonable amount of time to help students learn STEM topics. This competitive initiative sponsored four teams that separately developed systems that covered topics in mathematics, electronics, and dynamical systems. After the teams shared their progress at the conclusion of an 18-month period, the ONR decided to fund a joint applied project in the Navy that integrated those systems on the subject matter of electronic circuits. The University of Memphis took the lead in integrating these systems in an intelligent tutoring system called ElectronixTutor. This article describes the architecture of ElectronixTutor, the learning resources that feed into it, and the empirical findings that support the effectiveness of its constituent ITS learning resources. RESULTS: A fully integrated ElectronixTutor was developed that included several intelligent learning resources (AutoTutor, Dragoon, LearnForm, ASSISTments, BEETLE-II) as well as texts and videos. The architecture includes a student model that has (a) a common set of knowledge components on electronic circuits to which individual learning resources contribute and (b) a record of student performance on the knowledge components as well as a set of cognitive and non-cognitive attributes. There is a recommender system that uses the student model to guide the student on a small set of sensible next steps in their training. The individual components of ElectronixTutor have shown learning gains in previous decades of research. CONCLUSIONS: The ElectronixTutor system successfully combines multiple empirically based components into one system to teach a STEM topic (electronics) to students. A prototype of this intelligent tutoring system has been developed and is currently being tested. ElectronixTutor is unique in its assembling a group of well-tested intelligent tutoring systems into a single integrated learning environment.
RESUMEN
Rodent-borne hantaviruses cause hemorrhagic fever with renal syndrome (HFRS) in the old world and hantavirus cardio-pulmonary syndrome (HCPS) in the new. Most cases of HCPS in North America are caused by Sin Nombre Virus (SNV). Current viral detection technologies depend upon the identification of anti-viral antibodies in patient serum. Detection of viral antigen may facilitate earlier detection of the pathogen. We describe here the characterization of two single-chain Fv antibodies (scFvs), selected from a large naïve phage antibody library, which are capable of identifying the Sin Nombre Virus nucleocapsid protein (SNV-N), with no cross reactivity with the nucleocapsid protein from other hantaviruses. The utility of such selected scFvs was increased by the creation of an scFv-alkaline phosphatase fusion protein which was able to directly detect virally produced material without the need for additional reagents.
Asunto(s)
Anticuerpos Antivirales/inmunología , Síndrome Pulmonar por Hantavirus/inmunología , Región Variable de Inmunoglobulina/inmunología , Proteínas de la Nucleocápside/inmunología , Virus Sin Nombre/inmunología , Fosfatasa Alcalina/genética , Fosfatasa Alcalina/inmunología , Animales , Anticuerpos Antivirales/genética , Afinidad de Anticuerpos , Especificidad de Anticuerpos , Chlorocebus aethiops , Clonación Molecular , Reacciones Cruzadas , Ensayo de Inmunoadsorción Enzimática , Síndrome Pulmonar por Hantavirus/diagnóstico , Región Variable de Inmunoglobulina/genética , Proteínas de la Nucleocápside/análisis , Proteínas de la Nucleocápside/genética , Biblioteca de Péptidos , Proteínas Recombinantes de Fusión/inmunología , Proteínas Recombinantes/inmunología , Virus Sin Nombre/genética , Células VeroRESUMEN
Molecules of N-(4'-iodophenylsulfonyl)-4-nitroaniline, 4-O2NC6H4NHSO2C6H4I-4' (1), are linked by three-centre I...O2N interactions into chains and these chains are linked into a three-dimensional framework by C-H...O hydrogen bonds. In the isomeric N-(4'-nitrophenylsulfonyl)-4-iodoaniline, 4-IC6H4NHSO2C6H4NO2-4' (2), the chains generated by the I...O2N interactions are again linked into a three-dimensional framework by C-H...O hydrogen bonds. Molecules of N,N-bis(3'-nitrophenylsulfonyl)-4-iodoaniline, 4-IC6H4N(SO2C6H4NO(2)-3')2 (3), lie across twofold rotation axes in space group C2/c and they are linked into chains by paired I.O=S interactions: these chains are linked into sheets by a C-H...O hydrogen bond, and the sheets are linked into a three-dimensional framework by aromatic pi... stacking interactions. In N-(4'-iodophenylsulfonyl)-3-nitroaniline, 3-O2NC6H4NHSO2C6H4I-4' (4), there are R2(2)(8) rings formed by hard N-H...O=S hydrogen bonds and R2(2)(24) rings formed by two-centre I.nitro interactions, which together generate a chain of fused rings: the combination of a C-H...O hydrogen bond and aromatic pi...pi stacking interactions links the chains into sheets. Molecules of N-(4'-iodophenylsulfonyl)-4-methyl-2-nitroaniline, 4-CH3-2-O2NC6H3NHSO2C6H4I-4' (5), are linked by N-H...O=S and C-H...O(nitro) hydrogen bonds into a chain containing alternating R2(2)(8) and R2(2)(10) rings, but there are no I...O interactions of either type. There are two molecules in the asymmetric unit of N-(4'-iodophenylsulfonyl)-2-nitroaniline, 2-O2NC6H4NHSO2C6H4I-4' (6), and the combination of an I...O=S interaction and a hard N-H...O(nitro) hydrogen bond links the two types of molecule to form a cyclic, centrosymmetric four-component aggregate. C-H...O hydrogen bonds link these four-molecule aggregates to form a molecular ladder. Comparisons are made with structures retrieved from the Cambridge Structural Database.
