CuInS₂ quantum dots encapsulated in ZnS shells have emerged as less-toxic alternatives to cadmium-based nanoparticles. A well-established synthesis route for hydrophobic CIS/ZnS core/shell QDs has been developed using dodecanethiol as a ligand, solvent and source of sulfur, although the transfer of these nanoparticles into the aqueous phase still proves to be non-trivial. In this study we demonstrate that coating CIS/ZnS with an amphipol, poly(maleic anhydride-alt-1-tetradecene), 3-(dimethylamino)-1-propylamine derivative is an effective method to disperse CIS/ZnS QDs in the aqueous environment. The polymer-coated QDs display good colloidal stability over a wide pH range and low sensitivity to the presence of various metal salts, except Cu²⁺ for which some sensitivity is observed. Cytotoxic effects were tested in HaCat cells and compared to thioglycolic acid modified CdTe/ZnS QDs. Neither CdTe nor CIS QDs decreased viability until above 10 μg mL⁻¹ in a WST-1 assay. By also assessing the toxicity of the PMAL-d polymer it is clear that remaining toxicity of the CIS/ZnS QDs is predominately due to the polymer coating rather than the QD core. Interestingly, MTT assays seem to artificially exaggerate cytotoxicity of the QDs, which we ascribe to the QDs interfering with the MTT or formazan crystals.

We report observation of highly-segregated compositional domains within CuInS ₂ quantum dots, showing the origin of their emission-mediating In _Cu defect.

For the past five decades, the majority of science education has adhered to a pedagogical philosophy which contends that issues in the acquisition and expression of target scientific narratives by learners stem from the existence of “incorrect beliefs” called misconceptions. According to this philosophy, misconceptions must be identified, possibly as early as in childhood, and eradicated with specific interventions to allow the proper scientific knowledge to be acquired. Despite much effort cataloging misconceptions and their associated interventions in different disciplines and sub-branches of these disciplines, misconceptions get still regularly diagnosed in a wide academic population ranging from school pupils to teachers in training, and even experts. In addition to this potential lack of efficacy, the present article puts forward three lines of argument making the case against the adoption of a science pedagogy based on a belief-change strategy in learners. The suggested lines of argument rely on ethical, epistemic, and professional considerations. It is then argued that adopting a pedagogical philosophy based on representational pluralism, in opposition to holding a single “true” scientific story, can both address the three points of concern aforementioned, but also allow learners to bypass misconceptions when making judgements based on their scientific knowledge. Possible applications in physics education are presented.

Statistical Hypothesis Testing (SHT) is a class of inference methods whereby one makes use of empirical data to test a hypothesis and often emit a judgment about whether to reject it or not. In this paper, we focus on the logical aspect of this strategy, which is largely independent of the adopted school of thought, at least within the various frequentist approaches. We identify SHT as taking the form of an unsound argument from Modus Tollens in classical logic, and, in order to rescue SHT from this difficulty, we propose that it can instead be grounded in t-norm based fuzzy logics. We reformulate the frequentists’ SHT logic by making use of a fuzzy extension of Modus Tollens to develop a model of truth valuation for its premises. Importantly, we show that it is possible to preserve the soundness of Modus Tollens by exploring the various conventions involved with constructing fuzzy negations and fuzzy implications (namely, the S and R conventions). We find that under the S convention, it is possible to conduct the Modus Tollens inference argument using Zadeh’s compositional extension and any possible t-norm. Under the R convention we find that this is not necessarily the case, but that by mixing R-implication with S-negation we can salvage the product t-norm, for example. In conclusion, we have shown that fuzzy logic is a legitimate framework to discuss and address the difficulties plaguing frequentist interpretations of SHT.