Sun Yat-sen University

About: Sun Yat-sen University is a education organization based out in Guangzhou, Guangdong, China. It is known for research contribution in the topics: Population & Cancer. The organization has 115149 authors who have published 113763 publications receiving 2286465 citations. The organization is also known as: Zhongshan University & SYSU.

Cationic Surfactant-Type Electrolyte Additive Enables Three-Dimensional Dendrite-Free Zinc Anode for Stable Zinc-Ion Batteries

Abstract: Zn metal has been considered as a promising anode material for rechargeable aqueous metal-ion batteries. However, the propensity of dendrite growth during plating restricts its practical applicatio...

Safety of Nanoparticles in Medicine.

Abstract: Nanomedicine involves the use of nanoparticles for therapeutic and diagnostic purposes. During the past two decades, a growing number of nanomedicines have received regulatory approval and many more show promise for future clinical translation. In this context, it is important to evaluate the safety of nanoparticles in order to achieve biocompatibility and desired activity. However, it is unwarranted to make generalized statements regarding the safety of nanoparticles, since the field of nanomedicine comprises a multitude of different manufactured nanoparticles made from various materials. Indeed, several nanotherapeutics that are currently approved, such as Doxil and Abraxane, exhibit fewer side effects than their small molecule counterparts, while other nanoparticles (e.g. metallic and carbon-based particles) tend to display toxicity. However, the hazardous nature of certain nanomedicines could be exploited for the ablation of diseased tissue, if selective targeting can be achieved. This review discusses the mechanisms for molecular, cellular, organ, and immune system toxicity, which can be observed with a subset of nanoparticles. Strategies for improving the safety of nanoparticles by surface modification and pretreatment with immunomodulators are also discussed. Additionally, important considerations for nanoparticle safety assessment are reviewed. In regards to clinical application, stricter regulations for the approval of nanomedicines might not be required. Rather, safety evaluation assays should be adjusted to be more appropriate for engineered nanoparticles.

Telomere lengthening early in development.

Abstract: Stem cells and cancer cells maintain telomere length mostly through telomerase. Telomerase activity is high in male germ line and stem cells, but is low or absent in mature oocytes and cleavage stage embryos, and then high again in blastocysts. How early embryos reset telomere length remains poorly understood. Here, we show that oocytes actually have shorter telomeres than somatic cells, but their telomeres lengthen remarkably during early cleavage development. Moreover, parthenogenetically activated oocytes also lengthen their telomeres, thus the capacity to elongate telomeres must reside within oocytes themselves. Notably, telomeres also elongate in the early cleavage embryos of telomerase-null mice, demonstrating that telomerase is unlikely to be responsible for the abrupt lengthening of telomeres in these cells. Coincident with telomere lengthening, extensive telomere sister-chromatid exchange (T-SCE) and colocalization of the DNA recombination proteins Rad50 and TRF1 were observed in early cleavage embryos. Both T-SCE and DNA recombination proteins decrease in blastocyst stage embryos, whereas telomerase activity increases and telomeres elongate only slowly. We suggest that telomeres lengthen during the early cleavage cycles following fertilization through a recombination-based mechanism, and that from the blastocyst stage onwards, telomerase only maintains the telomere length established by this alternative mechanism.

Statistical Tests for Detecting Positive Selection by Utilizing High-Frequency Variants

Abstract: By comparing the low-, intermediate-, and high-frequency parts of the frequency spectrum, we gain information on the evolutionary forces that influence the pattern of polymorphism in population samples We emphasize the high-frequency variants on which positive selection and negative (background) selection exhibit different effects We propose a new estimator of θ (the product of effective population size and neutral mutation rate), θ L , which is sensitive to the changes in high-frequency variants The new θ L allows us to revise Fay and Wu's H -test by normalization To complement the existing statistics (the H -test and Tajima's D -test), we propose a new test, E , which relies on the difference between θ L and Watterson's θW We show that this test is most powerful in detecting the recovery phase after the loss of genetic diversity, which includes the postselective sweep phase The sensitivities of these tests to (or robustness against) background selection and demographic changes are also considered Overall, D and H in combination can be most effective in detecting positive selection while being insensitive to other perturbations We thus propose a joint test, referred to as the DH test Simulations indicate that DH is indeed sensitive primarily to directional selection and no other driving forces

High-Q Quasibound States in the Continuum for Nonlinear Metasurfaces.

Abstract: Sharp electromagnetic resonances play an essential role in physics in general and optics in particular. The last decades have witnessed the successful developments of high-quality ($Q$) resonances in microcavities operating below the light line, which however is fundamentally challenging to access from free space. Alternatively, metasurface-based bound states in the continuum (BICs) offer a complementary solution of creating high-$Q$ resonances in devices operating above the light line, yet the experimentally demonstrated $Q$ factors under normal excitations are still limited. Here, we present the realizations of quasi-BIC under normal excitation with a record $Q$ factor up to 18 511 by engineering the symmetry properties and the number of the unit cells in all-dielectric metasurface platforms. The high-$Q$ quasi-BICs exhibit exceptionally high conversion efficiency for the third harmonic generation and even enable the second harmonic generation in Si metasurfaces. Such ultrasharp resonances achieved in this work may immediately boost the performances of BICs in a plethora of fundamental research and device applications, e.g., cavity QED, biosensing, nanolasing, and quantum light generations.