Ultrafast carrier relaxation dynamics in fluorescent carbon nanodots is investigated by femtosecond transient absorption spectra at different pH environments so as to understand the mechanism of fluorescence for the first time. Utilizing multi-wavelength global analysis to fit the measured signal via a sequential model, four different relaxation channels are found, which are attributed to electron-electron scattering and surface state trapping, optical phonon scattering, acoustic phonon scattering and electron-hole recombination respectively. The results reveal that the surface states are mainly composed of different oxygen-containing functional groups (epoxy, carbonyl and carboxyl) and carbon atoms on the edge of the carbon backbone and can effectively trap a large number of photo-excited electrons. The deprotonation of carboxyl groups at high pH will change the distribution of π electron cloud density between the carbon backbone and surface states and consequently, compared with the excited electrons in the acidic and neutral environments, those in the alkaline environment can be more easily trapped by the surface within 1 ps, thereby giving rise to stronger fluorescence emission.

We theoretically investigated the generation progress of high-order harmonics utilizing Bohmian trajectories, which are calculated from the accurate numerical wave function. It is found that the harmonic emission spectrum from atoms in an intense laser field calculated by Bohmian trajectories agrees well with that found by numerically solving the time-dependent Schrödinger equation. Through the analysis of the dynamic behavior of Bohmian trajectories, we investigated the ionization process, the acceleration of the ionized electron in the laser field, and its recollision with the parent ion in the progress. Furthermore, the individual behavior and the coherent contribution of these trajectories to the harmonic emission are discussed.

Objective:Pretreatment of myoinositol is a very new method that was evaluated in multiple small studies to manage poor ovarian response in assisted reproduction. This study was to determine the efficacy of myoinositol supplement in infertile women undergoing ovulation induction for intracytoplasmic sperm injection (ICSI) or in vitro fertilization embryo transfer (IVF-ET).Methods:A meta-analysis and systematic review of published articles evaluating the efficacy of myo-inositol in patients undergoing ovulation induction for ICSI or IVF-ET was performed.Results:Seven trials with 935 women were included. Myoinositol supplement was associated with significantly improved clinical pregnancy rate [95% confidence interval (CI), 1.04–1.96; P = .03] and abortion rate (95% CI, 0.08–0.50; P = .0006). Meanwhile, Grade 1 embryos proportion (95% CI, 1.10–2.74; P = .02), germinal vescicle and degenerated oocytes retrieved (95% CI, 0.11–0.86; P = .02), and total amount of ovulation drugs (95% CI, –591.69 to –210.39; P = .001) were also improved in favor of myo-inositol. There were no significant difference in total oocytes retrieved, MII stage oocytes retrieved, stimulation days, and E2 peak level.Conclusions:Myoinositol supplement increase clinical pregnancy rate in infertile women undergoing ovulation induction for ICSI or IVF-ET. It may improve the quality of embryos, and reduce the unsuitable oocytes and required amount of stimulation drugs.