Bilingualism, Language Proficiency, and Learning to Read in Two Writing Systems.

Two hundred and four 5- and 6-year-olds who were monolingual English-, bilingual English-Chinese-, or Chinese-speaking children beginning to learn English (2nd-language learners) were compared on phonological awareness and word decoding tasks in English and Chinese. Phonological awareness developed in response to language exposure and instruction but, once established, transferred across languages for both bilinguals and 2nd-language learners. In contrast, decoding ability developed separately for each language as a function of proficiency and instruction in that language and did not transfer to the other language. Therefore, there was no overall effect of bilingualism on learning to read: Performance depended on the structure of the language, proficiency in that language, and instructional experiences with that writing system. These results point to the importance of evaluating the features of the languages and instructional context in which children become biliterate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

D-Peptide and D-Protein Technology: Recent Advances,Challenges, and Opportunities**

Total chemical protein synthesis provides access to entire D-protein enantiomers enabling unique applications in molecular biology, structural biology, and bioactive compound discovery. Key enzymes involved in the central dogma of molecular biology have been prepared in their D-enantiomeric forms facilitating the development of mirror-image life. Crystallization of a racemic mixture of L- and D-protein enantiomers provides access to high-resolution X-ray structures of polypeptides. Additionally, D-enantiomers of protein drug targets can be used in mirror-image phage display allowing discovery of non-proteolytic D-peptide ligands as lead candidates. This review discusses the unique applications of D-proteins including the synthetic challenges and opportunities.     

Magnetic Polaron States in Photoluminescent Carbon Dots Enable Hydrogen Peroxide Photoproduction (Small 32/2023)

Photoactivation of aspartic acid-based carbon dots (Asp-CDs) induces the generation of spin-separated species, including electron/hole (e⁻/h⁺) polarons and spin-coupled triplet states, as uniquely confirmed by the light-induced electron paramagnetic resonance spectroscopy. The relative population of the e⁻/h⁺ pairs and triplet species depends on the solvent polarity, featuring a substantial stabilization of the triplet state in a non-polar environment (benzene). The electronic properties of the photoexcited Asp-CDs emerge from their spatial organization being interpreted as multi-layer assemblies containing a hydrophobic carbonaceous core and a hydrophilic oxygen and nitrogen functionalized surface. The system properties are dissected theoretically by density functional theory in combination with molecular dynamics simulations on quasi-spherical assemblies of size-variant flakelike model systems, revealing the importance of size dependence and interlayer effects. The formation of the spin-separated states in Asp-CDs enables the photoproduction of hydrogen peroxide (H₂O₂) from water and water/2-propanol mixture via a water oxidation reaction.     

Spatio-Temporal Photoactivation of Cytotoxic Proteins

Protein therapeutics offer exquisite selectivity in targeting cellular processes and behaviors, but are rarely used against non-cell surface targets due to their poor cellular uptake. While cell-penetrating peptides can be used to deliver recombinant proteins to the cytosol, it is generally difficult to selectively deliver active proteins to target cells. Here, we report a recombinantly produced, intracellular protein delivery and targeting platform that uses a photocaged intein to regulate the spatio-temporal activation of protein activity in selected cells upon irradiation with light. The platform was successfully demonstrated for two cytotoxic proteins to selectively kill cancer cells after photoactivation of intein splicing. This platform can generically be applied to any protein whose activity can be disrupted by a fused intein, allowing it to underpin a wide variety of future protein therapeutics.