Models of classroom assessment for course-based research experiences

Course-based research pedagogy involves positioning students as contributors to authentic research projects as part of an engaging educational experience that promotes their learning and persistence in science. To develop a model for assessing and grading students engaged in this type of learning experience, the assessment aims and practices of a community of experienced course-based research instructors were collected and analyzed. This approach defines four aims of course-based research assessment—(1) Assessing Laboratory Work and Scientific Thinking; (2) Evaluating Mastery of Concepts, Quantitative Thinking and Skills; (3) Appraising Forms of Scientific Communication; and (4) Metacognition of Learning—along with a set of practices for each aim. These aims and practices of assessment were then integrated with previously developed models of course-based research instruction to reveal an assessment program in which instructors provide extensive feedback to support productive student engagement in research while grading those aspects of research that are necessary for the student to succeed. Assessment conducted in this way delicately balances the need to facilitate students’ ongoing research with the requirement of a final grade without undercutting the important aims of a CRE education

Diagnostic and follow-up performance of serological tests for different forms/courses of alveolar echinococcosis

Diagnosis of alveolar echinococcosis (AE) is predominantly based on imaging procedures combined with immunodiagnostic testing. In the present study, we retrospectively analyzed the performance of four serological tests (EgHF-ELISA, Em2-ELISA, recEm18-ELISA and Em-Immunoblotting) for initial diagnosis and subsequent monitoring of AE patients. Overall, 101 AE patients were included, grouped according to treatment options and immune status as follows: (A) curative surgical treatment (n = 45 patients), (B) non-radical or palliative surgical treatment (n = 11), (C) benzimidazoles only (n = 20), (D) immunocompromised with radical surgical treatment (n = 11), (E) immunocompromised with benzimidazoles only (n = 4), and finally a group of 10 AE patients (F) that were considered to present so-called "abortive" lesions. Initial (i.e. pretreatment) ELISA-based diagnosis for patients in groups A to E revealed overall diagnostic sensitivities of 95% for EgHF, 86% for Em2, and 80% for recEm18, respectively. Comparatively, the diagnostic sensitivity of Em-Immunoblotting was higher with an overall value of 98%. In group F, only Em-Immunoblotting had an excellent diagnostic sensitivity (100%), whereas the ELISAs had poor sensitivities of 30% (EgHF- and Em2-ELISA) or even 0% (recEm18-ELISA). Serological monitoring of AE patients showed a clear association between a curative development of disease (induced either by surgery or benzimidazole medication) and a negativization in the ELISAs. This effect was most pronounced for the recEm18-ELISA, where 56% negativized following diagnosis/treatment, as compared to 36% for the EgHF-ELISA, and 37% for the Em2-ELISA, respectively. After radical surgery, the mean time until negativization in the recEm18-ELISA was 2.4 years (SD 1.6). This was significantly shorter than the mean 3.9 years (SD 2.5) in those AE patients with non-radical, palliative surgery or ABZ treatment who were able to negativize during the study period (p = 0.048). Conclusively, Em-Immunoblotting appears as the most sensitive test to diagnose active as well as inactive ("abortive") AE-cases. The inclusion of the ELISAs completes the initial diagnostic picture and offers valuable additional information. Conversely, recEm18-ELISA appears as the currently best serological tool to monitor a regressive and putatively curative course of AE in treated patients

Comparative assessment of ELISAs using recombinant saposin-like protein 2 and recombinant cathepsin L-1 from Fasciola hepatica for the serodiagnosis of human Fasciolosis.

Two recombinant Fasciola hepatica antigens, saposin-like protein-2 (recSAP2) and cathepsin L-1 (recCL1), were assessed individually and in combination in enzyme-linked immunosorbent assays (ELISA) for the specific serodiagnosis of human fasciolosis in areas of low endemicity as encountered in Central Europe. Antibody detection was conducted using ProteinA/ProteinG (PAG) conjugated to alkaline phosphatase. Test characteristics as well as agreement with results from an ELISA using excretory-secretory products (FhES) from adult stage liver flukes was assessed by receiver operator characteristic (ROC) analysis, specificity, sensitivity, Youdens J and overall accuracy. Cross-reactivity was assessed using three different groups of serum samples from healthy individuals (n=20), patients with other parasitic infections (n=87) and patients with malignancies (n=121). The best combined diagnostic results for recombinant antigens were obtained using the recSAP2-ELISA (87% sensitivity, 99% specificity and 97% overall accuracy) employing the threshold (cut-off) to discriminate between positive and negative reactions that maximized Youdens J. The findings showed that recSAP2-ELISA can be used for the routine serodiagnosis of chronic fasciolosis in clinical laboratories; the use of the PAG-conjugate offers the opportunity to employ, for example, rabbit hyperimmune serum for the standardization of positive controls

Multi-Graph ROC curve showing the empirical value for sensitivity (red), specificity (blue), overall accuracy (green) and Youdens J (violet) as a function of the cutoff value, exemplified in function of the recSAP2-ELISA selected as best operating ELISA among the four assays investigated.

<p>The blue line indicates the cutoff (0.084) at which the overall test performance turned out to be optimal.</p

Western blot analyses of recSAP2-antigen.

<p>Arrow indicates the 15 Mr size of the revealed recombinant and affinity-purified protein. Western blot findings concerning six different sera from fascioliosis patients with different FhES-ELISA-αhuIgG-AP antibody levels (see text).</p

Degree of cross-reactivity found with the four antigens assessed by ELISA, and based upon a discrimination between positive versus negative reaction (Youdens J max), yielding thus a relative specificity index with regard to cross-reactive parasitic disease sera.

<p>ntot = total number of sera tested; npos = number of positive sera.</p

Dot plot showing the distribution of A_{405 nm} values (y-axis) for the four antigens/ELISAs and for the four groups of sera tested (Fh-infection; healthy blood donors; cancer-patients, sera from patients with other parasitoses).

<p>The dotted lines indicate the respective Youndens J max values as shown in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002860#pntd-0002860-t002" target="_blank">Tab. 2</a> and used as threshold discriminating between positive and negative serology.</p

Selected cutoff values (*) for which the maximized accuracy criterion (diagnostic sensitivity, diagnostic specificity, overall agreement and combined SE and SP (Youdens J)) was achieved; the table includes also the ROC AUC for the four different <i>Fasciola</i>-ELISAs.

<p>Selected cutoff values (*) for which the maximized accuracy criterion (diagnostic sensitivity, diagnostic specificity, overall agreement and combined SE and SP (Youdens J)) was achieved; the table includes also the ROC AUC for the four different <i>Fasciola</i>-ELISAs.</p

Empirical ROC curves for the four antigens/ELISAs tested.

<p>Empirical ROC curves for the four antigens/ELISAs tested.</p