Using separable non-negative matrix factorization techniques for the analysis of time-resolved Raman spectra

The key challenge of time-resolved Raman spectroscopy is the identification of the constituent species and the analysis of the kinetics of the underlying reaction network. In this work we present an integral approach that allows for determining both the component spectra and the rate constants simultaneously from a series of vibrational spectra. It is based on an algorithm for non-negative matrix factorization which is applied to the experimental data set following a few pre-processing steps. As a prerequisite for physically unambiguous solutions, each component spectrum must include one vibrational band that does not significantly interfere with vibrational bands of other species. The approach is applied to synthetic "experimental" spectra derived from model systems comprising a set of species with component spectra differing with respect to their degree of spectral interferences and signal-to-noise ratios. In each case, the species involved are connected via monomolecular reaction pathways. The potential and limitations of the approach for recovering the respective rate constants and component spectra are discussed

Communicative learning outcomes and world language edTPA: Characteristics of high-scoring portfolios

Teacher accountability continues to be at the forefront of educational policy in the United States, with the current focus on the Outcomes of K-12 teaching and teacher education (Cochran-Smith 2000). edTPA, a high-stakes assessment used in many states to make licensure or certification decisions, purports to measure those content-specific outcomes. This study investigated pre-service Spanish teachers’ performance on the World Language edTPA as it relates to planning for instruction in a communicative context. Specifically, the ave highest scoring edTPA portfolios from two large world language teacher education programs were examined, with a focus on their alignment with communicative language teaching approaches and Gronlund’s (2004) criteria for articulating student learning outcomes. Results showed serious discrepancies among the candidates’ learning outcomes, communicative language teaching approaches, and the spirit of the World Language edTPA. This research has implications for teacher preparation and professional development of beginning language teachers

Concepts in bio-molecular spectroscopy: vibrational case studies on metalloenzymes

Spectroscopic techniques play a major role in the elucidation of structure-function relationships of biological macromolecules. Here we describe an integrated approach for bio-molecular spectroscopy that takes into account the special characteristics of such compounds. The underlying fundamental concepts will be exemplarily illustrated by means of selected case studies on biocatalysts, namely hydrogenase and superoxide reductase. The treatise will be concluded with an overview of challenges and future prospects, laying emphasis on functional dynamics, in vivo studies, and computational spectroscopy.DFG, EXC 314, Unifying Concepts in Catalysi

Re-examining teacher candidate performance on world language edTPA as a consequential assessment

Used by almost 800 educator preparation programs in more than 40 states and the District of Columbia, edTPA seeks to measure content-specific outcomes of beginning teachers as a high-stakes assessment. Many states also use edTPA to inform teacher licensure or certification decisions, making the assessment consequential for individual teacher candidates. The present study focuses on teacher candidates’ performance on the World Language edTPA, targeting two world language teacher education programs since the assessment became consequential for licensure in their respective states. It then compares findings to those of a previous study of the same programs’ World Language edTPA performance (Hildebrandt & Swanson, 2014) from before the assessment became consequential for teacher licensure decisions in 2015 in [State X] and [State Y]. Programmatic changes were implemented after initial inspection of the data and results from such curricular changes are discussed in terms of local impact. Additionally, national trends are identified and discussed. Findings demonstrate serious issues regarding this assessment of beginning teacher effectiveness as related to World Language teaching and learning. This research has implications for teacher preparation programs and other educational stakeholders alike

World Language Teacher Candidate Performance on edTPA: An Exploratory Study

Federal and state legislation continues to promote teacher accountability in the United States. The new edTPA, a subject-specific teacher performance assessment, is purported to measure beginning teacher readiness and is being pilot tested and implemented for licensure and certification decisions across the country. In this exploratory quantitative study, the researchers examined edTPA scores of 21 world language teacher candidates from two teacher preparation programs and compared those results to the cut scores for the states of Washington and New York. Results indicated that participants performed best in the planning section and were most challenged by the assessment section. This research has implications for teacher certification candidates, world language teacher preparation programs, policy makers, and other stakeholders

Surface enhanced resonance Raman detection of a catalytic intermediate of DyP-type peroxidase

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.We report herein the vibrational spectroscopic characterisation of a catalytic intermediate formed by the reaction of H2O2 with DyP-type peroxidase immobilised on a biocompatible coated metal support. The SERR spectroscopic approach is of general applicability to other peroxidases which form relatively stable catalytic intermediates.DFG, EXC 314, Unifying Concepts in Catalysi

Efficient Interpretation of Tandem Mass Tags in Top-Down Proteomics

Mass spectrometry is the major analytical tool for the identification and quantification of proteins in biological samples. In so-called top-down proteomics, separation and mass spectrometric analysis is performed at the level of intact proteins, without preparatory digestion steps. It has been shown that the tandem mass tag (TMT) labeling technology, which is often used for quantification based on digested proteins (bottom-up studies), can be applied in top-down proteomics as well. This, however, leads to a complex interpretation problem, where we need to annotate measured peaks with their respective generating protein, the number of charges, and the a priori unknown number of TMT-groups attached to this protein. In this work, we give an algorithm for the efficient enumeration of all valid annotations that fulfill available experimental constraints. Applying the algorithm to real-world data, we show that the annotation problem can indeed be efficiently solved. However, our experiments also demonstrate that reliable annotation in complex mixtures requires at least partial sequence information and high mass accuracy and resolution to go beyond the proof-of-concept stage

Surface enhanced vibrational spectroscopic evidence for an alternative DNA-independent redox activation of endonuclease III

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Surface enhanced vibrational spectro-electrochemistry of endonuclease III provides direct evidence that the [4Fe-4S] cluster is responsible for the enzyme redox activity, and that this process is not exclusively DNA-mediated, as currently proposed. We report the first surface enhanced resonance Raman spectrum of a [4Fe-4S](2+) cluster containing enzyme.DFG, EXC 314, Unifying Concepts in Catalysi