Biobased and environmental-friendly polylactones provide a solution to the increasing crisis of fossilsourced products. Ring-opening polymerization (ROP) of ε-decalactone (DL) catalyzed by lanthanum tris(2,6-di-tert-butyl-4-methylphenolate) [La(OAr) 3 ] and lanthanum tris-(borohydride) [La(BH 4 ) 3 (THF) 3 ] is reported for the first time in this paper. Both of them exhibit good activities producing poly(ε-decalactone) (PDL) with molecular weight (MW) up to 26.4 kg/mol and polydispersity index (PDI) as low as 1.10. PLLA-b-PDL-b-PEG-b-PDL-b-PLLA pentablock copolymers with predictable MWs and relatively narrow PDIs (1.19−1.28) are synthesized by sequential ROP of DL and Llactide (LLA) catalyzed by La(OAr) 3 in the presence of poly(ethylene glycol) (PEG). Chain extension reactions of the obtained pentablock copolymers are carried out using L-lysine diisocyanate (LDI) to produce multiblock copolymers with relatively high MW. The thermal behaviors studied by DSC and DMA measurements indicate that PDL is completely amorphous under ambient temperature and the copolymers with two T g s suggest microphase separation of hard and soft domains. We employ tensile tests to assess mechanical properties and find excellent elongation up to 723% of the chain-extended samples. Considering the biorenewable resource of DL and LLA, a novel, biobased, biodegradable, and biocompatible elastomer is successfully synthesized.

Visible light communication (VLC) is an advanced and high-efficiency wireless communication technology. As one of the most important light sources in VLC, conventional white light emitting diode (WLED) based on Y₃Al₅O₁₂:Ce³⁺ (YAG:Ce) phosphor limits the system transmitting rate severely due to its narrow modulation bandwidth. Considering the short fluorescent lifetime of quantum dots (QDs), QD-LEDs with wide modulation bandwidths were designed here to improve the transmitting rate of VLC. CdSe/ZnS core/shell QDs and related luminescent microspheres (LMS) were implemented as light conversion materials for the QD-LEDs. Compared with conventional phosphor WLED, the proposed QD-LED and QD-WLED reached maximum improvement on modulation bandwidth at 74.19% and 67.75% respectively. Furthermore, mathematical modeling of smearing was analyzed to establish the relationship between fluorescent lifetime and modulation bandwidth. Our findings will provide an effective solution of white LEDs for high speed VLC.

Meiotic recombination ensures accurate homologous chromosome segregation during meiosis and generates novel allelic combinations among gametes. During meiosis, DNA double strand breaks (DSBs) are generated to facilitate recombination. To maintain genome integrity, meiotic DSBs must be repaired using appropriate DNA templates. Although the DNA damage response protein kinase Ataxia-telangiectasia mutated (ATM) has been shown to be involved in meiotic recombination in Arabidopsis , its mechanistic role is still unclear. In this study, we performed cytological analysis in Arabidopsis atm mutant, we show that there are fewer γH2AX foci, but more RAD51 and DMC1 foci on atm meiotic chromosomes. Furthermore, we observed an increase in meiotic Type I crossovers (COs) in atm. Our genetic analysis shows that the meiotic phenotype of atm rad51 double mutants is similar to the rad51 single mutant. Whereas, the atm dmc1 double mutant has a more severe chromosome fragmentation phenotype compared to both single mutants, suggesting that ATM functions in concert with RAD51, but in parallel to DMC1. Lastly, we show that atm asy1 double mutants also have more severe meiotic recombination defects. These data lead us to propose a model wherein ATM promotes RAD51-mediated meiotic DSB repair by inter-sister-chromatid (IS) recombination in Arabidopsis .

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Transition metal dichalcogenide (TMD) quantum dots (QDs) with defects have attracted interesting chemistry due to the contribution of vacancies to their unique optical, physical, catalytic, and electrical properties. Engineering defined defects into molybdenum sulfide (MoS2) QDs is challenging. Herein, by applying a mild biomineralization‐assisted bottom‐up strategy, blue photoluminescent MoS2 QDs (B‐QDs) with a high density of defects are fabricated. The two‐stage synthesis begins with a bottom‐up synthesis of original MoS2 QDs (O‐QDs) through chemical reactions of Mo and sulfide ions, followed by alkaline etching that creates high sulfur‐vacancy defects to eventually form B‐QDs. Alkaline etching significantly increases the photoluminescence (PL) and photo‐oxidation. An increase in defect density is shown to bring about increased active sites and decreased bandgap energy; which is further validated with density functional theory calculations. There is strengthened binding affinity between QDs and O2 due to lower gap energy (∆EST) between S1 and T1, accompanied with improved intersystem crossing (ISC) efficiency. Lowered gap energy contributes to assist e−–h+ pair formation and the strengthened binding affinity between QDs and 3O2. Defect engineering unravels another dimension of material properties control and can bring fresh new applications to otherwise well characterized TMD nanomaterials.