No abstract

Introducing self-assembly strategies into the construction of catalysts has been proven to have great advantages in asymmetric catalysis. We constructed two chiral metalla-triangles by highly efficient coordination-driven self-assembly from a chiral 3,3′-dipyridyl-substituted BINOL donor. They were successfully applied in asymmetric conjugate addition of a series of α,β-unsaturated ketones with trans-styrylboronic acids. The use of these metalla-triangles as supramolecular catalysts is obviously conducive to the enhancement of catalytic activity and stereoselectivity in the presented addition reactions. Under induction of the chiral metalla-triangles, an array of α,β-enones were converted to chiral γ,δ-unsaturated ketones in medium to quantitative yields (40–98%) with high enantioselectivities (87–96% ee).

Eggs of Pelodiscus sinensis were incubated under one fluctuating and four constant temperatures, and hatchlings from different incubation temperatures were maintained under identical conditions to assess the effects of incubation temperature on sexual phenotype and hatchling growth. The incubation length decreased as temperature increased, but it did not differ between sexes within each temperature treatment. Hatching success was higher at intermediate temperatures (28 • C, 30 • C and the fluctuating temperature regime) than at low (24 • C) and high (34 • C) temperatures. The sex ratio of hatchlings did not differ from equality within each temperature treatment. Thus, our data support previous work that P. sinensis does not have temperature-dependent sex determination, and add evidence for the prediction that turtles within the Trionychidae have genotypic sex determination exclusively. Incubation temperature affected hatchling mass, with hatchlings from intermediate incubation temperatures being heavier than those from low (24 • C) and high (34 • C) incubation temperatures. Hatching size was not a predictor of post-hatching growth. Incubation temperature affected hatchling growth, with hatchlings from 24 • C overall growing faster than did hatchlings from higher incubation temperatures. The influence of incubation temperature on hatchling growth was well buffered within the range of constant temperatures from 28 • C to 34 • C. Fluctuating incubation temperatures augmented male growth but reduced female growth, as female embryos were more vulnerable to extremely high temperatures.

Stem cell research provides promising strategies in improving healthcare for human beings. As a noninvasively obtained and easy-to-culture cell resource with relatively low expense, urine-derived stem cells have special advantages. They have been extensively studied on its proliferation ability and differentiation potential and were being reprogrammed to model diseases during the last decade. In this review, we intend to summarize the latest progress on the research of urine-derived stem cells for its broad application mainly in regenerative medicine and disease modeling, as well as in what is challenging currently. This minireview will highlight the potential application of urine-derived stem cells and provides possible direction of further research in the future.

Achieving higher sensitivity is an earnest purpose for precision metrology. As a response to this goal, the weak value amplification approach has been developed for measuring ultra-small physical effects, realizing sensitivity that had never been reached before. Encouraged by the successes, many efforts have been devoted to obtain ultimate sensitivity of weak value amplification. However, the benefit would be easily compromised in practice, because the cost of significant reduction on signal intensity leads to an ultra-low signal-to-noise ratio. In this work, we bridge this gap by proposing an alternative weak value amplification approach, which provides sensitivity several orders of magnitude higher than the standard approach while being compatible with practical imperfections. In the proof-of-principle experiment of measuring longitudinal phase change in time-domain, sensitivity up to 5 × 10 −4 attosecond is exemplified. Our approach can be applied to measure other small parameters with extremely high sensitivity, providing a new method for future precision metrology.

Autophagy is essential for the maintenance of cellular homeostasis and its dysfunction has been linked to various diseases. Autophagy is a membrane driven process and tightly regulated by membrane-associated proteins. Here, we summarized membrane lipid composition, and membrane-associated proteins relevant to autophagy from a spatiotemporal perspective. In particular, we focused on three important membrane remodeling processes in autophagy, lipid transfer for phagophore elongation, membrane scission for phagophore closure, and autophagosome-lysosome membrane fusion. We discussed the significance of the discoveries in this field and possible avenues to follow for future studies. Finally, we summarized the membrane-associated biochemical techniques and assays used to study membrane properties, with a discussion of their applications in autophagy.

Weak measurement is a novel technique for parameter estimation with higher precision. In this paper we develop a general theory for the parameter estimation based on weak measurement technique with arbitrary postselection. The previous weak value amplification model and the joint weak measurement model are two special cases in our theory. Applying the developed theory, the time-delay estimation is investigated in both theory and experiment. Experimental results shows that when the time-delay is ultra small, the joint weak measurement scheme outperforms the weak value amplification scheme, and is robust against not only the misalignment errors but also the wavelength-dependence of the optical components. These results are consistent with the theoretical predictions that has not been verified by any experiment before.

Development of sustainable routes for synthesizing aluminophosphate-based zeolites are very important because of their wide applications. As a typical sustainable route, solvent-free synthesis of zeolites not only decreases polluted wastes but also increases product yields. Systematic solvent-free syntheses of hierarchically porous aluminophosphate-based zeolites with AEL and AFI structures is presented. XRD patterns and SEM images show that these samples have high crystallinity. N2 sorption isotherm tests show that these samples are hierarchically porous, and their surface areas are comparable with those of corresponding zeolites from hydrothermal route. Chosen as an example, catalytic oxidation of ethylbenzene with O2 shows that cobalt substituted APO-11 from the solvent-free route (S-CoAPO-11) is more active than conventional CoAPO-11 from hydrothermal route owing to the sample hierarchical porosity.