What difference does a thiophene make? Evaluation of a 4,4′-bis(thiophene) functionalised 2,2′-bipyridyl copper(I) complex in a dye-sensitized solar cell

AbstractThe synthesis of a 4,4′-bis(2-thienyl-5-carboxylic acid) functionalised 2,2′-bipyridine ligand and corresponding copper(I) complex is described and its application in a dye-sensitized solar cell (DSSC) is studied. The positioning of the thiophene groups appears favourable from DFT analysis and a best efficiency of 1.41% was obtained with this dye, for a 0.3 cm2 cell area DSSC. Two absorbance bands are observed in the electronic absorption spectrum of the copper(I) complex at 316 nm and 506 nm, with ε values of 50,000 M−1 cm−1 and 9030 M−1 cm−1, respectively. Cyclic voltammetry and electrochemical impedance spectroscopy are also used to provide a detailed analysis of the dye and assess its functionality in a DSSC

Exploring the biographies of prospective science teachers: evolving perspectives on diversity and equity

textScience as a body of knowledge holds a highly regarded place in society. In recent years, science education has been the object of national scrutiny as the result of assessment data that indicates that the scientific literacy of students in the United States is marginal as compared to other advanced nations around the world. Students of color have been especially targeted due to the historical underrepresentation of this group in the sciences. Specifically access to a rigorous science curriculum and qualified teachers has been implicated in improving the chances of traditionally underserved students to participate and achieve in science. The aim of this study was to explore the perspectives (i.e., the beliefs, knowledge, and experiences) of prospective secondary science teachers regarding a science for all reform agenda. Constructivist, critical, and feminist methodologies were used to elicit prospective teachers’ views of equity in science teaching and learning as they described their experiences as science learners and prospective science teachers. The topic of multicultural science education served as a context for focus group conversations. Analysis of conversations revealed that participants’ lived experiences as learners and teachers-in-the-making shape their views of science and science education, their views of issues of diversity in teaching and learning, and their views of the organizational features of schooling. A dialogic relational perspective (DRP) model that attends to biography is proposed as a means for considering the roles of teacher, student, and science in relationship to the goals of science for all. The model is presented and discussed in the context of equity pedagogy for science teacher preparation and development.Science and Mathematics Educatio

Report of 2014 focus group interviews with CUES students

Brief summary of findings from focus group interviews of CUES students, covering the three main elements of the project: spatial visualization, enhanced tutoring and the engineering summer math institute.This work was supported by the National Science Foundation through grant NSF-131750

Plasma sex hormones and post reproductive period in the green frog. Rana esculenta complex.

The plasmatic profiles of androgens, estradiol, and progesterone, together with gonads and SSC modifications, have been followed, throughout the post-reproductive period in two Rana esculenta populations, inhabiting, respectively, a mountain poud (Colfiorito) and a sea level lagoon (Lesina). Testosterone and progesterone progressively decrease in the blood until July, while estradiol shows, in both sexes, an increase in the same month. Testosterone depletion accounts for thumb pad atrophy in the male and probably, in both sexes, for the summer interruption of sexual behavior. The estradiol increase could be linked to the induction of vitellogenin synthesis by the liver or, alternatively, could act through negative feed-back on the brain centers involved in GnRF synthesis and therefore it could be responsible for an inhibition of LH release and, in turn, of androgen synthesis/secretion by the gonads. The last function can be framed in the endocrine regulation of the so-called “refractory period” which interrupts the breeding during the summer. The hematic level of progesterone is higher during the ovulation period and this is consistent with the role assigned to the hormone, i.e., the induction of jelly release from oviductal glands. The hormonal trends in the blood of the two frog populations are very similar, although some differences exist in the levels of testosterone and progesterone