Strain Induced One-Dimensional Landau-Level Quantization in Corrugated Graphene

Theoretical research has predicted that ripples of graphene generates effective gauge field on its low energy electronic structure and could lead to zero-energy flat bands, which are the analog of Landau levels in real magnetic fields. Here we demonstrate, using a combination of scanning tunneling microscopy and tight-binding approximation, that the zero-energy Landau levels with vanishing Fermi velocities will form when the effective pseudomagnetic flux per ripple is larger than the flux quantum. Our analysis indicates that the effective gauge field of the ripples results in zero-energy flat bands in one direction but not in another. The Fermi velocities in the perpendicular direction of the ripples are not renormalized at all. The condition to generate the ripples is also discussed according to classical thin-film elasticity theory.Comment: 4 figures, Phys. Rev.

ELM of ELM-WD: An extremely low mass hot donor star discovered in LAMOST survey

The Extremely Low Mass White Dwarfs (ELM WDs) and pre-ELM WDs are helium core white dwarfs with mass $<\sim 0.3M_{\odot}$. They are formed in close binaries and have lost over half of their initial masses via Common Envelope (CE) ejection or stable Roche Lobe Over Flow (RLOF). Both evolution simulations and observations show that a lower mass limit for ELM WDs exists at $\approx0.14M_{\odot}$. Here we report the discovery of an extremely low mass ELM WD, ID70904216 in LAMOST survey, that may be lower than the ELM WD mass limit. Based on LAMOST and P200 spectroscopic observations, ID70904216 shows orbital period $P_{orb} =$ 0.219658 days and radial velocity semi-amplitude $K1=317.33km/s$, which gives the mass function of 0.73$M_{\odot}$, indicating the companion is a compact star. The low resolution spectra shows a F type star with $T_{\rm eff} \sim 7361K$ without emission features. The temperature is consistent with that derived from SED fitting($7440K$) and multi-color light curve solution($7400K$). The optical light curves, in ZTF g, r and i bands and Catalina V band, show ellipsoidal variability with amplitudes $\approx30\%$, suggesting that the visible companion is heavily tidal distorted. Combining with the distance from Gaia survey, the WD code modeling estimates that the mass of the visible star is $M1=0.08^{+0.06}_{-0.03}M_{\odot}$, and the mass of the invisible star is $M2=0.94^{+0.45}_{-0.10}M_{\odot}$. The radius of the visible donor is $R=0.29\pm0.01R_{\odot}$. The inclination angle is constrained between 60$^{\circ}$ and 90$^{\circ}$. The observations indicate the system is a pre-ELM WD + WD/NS binary system with an extremely low mass hot donor below the $0.14M_{\odot}$ theoretical limit.Comment: 16 pages, 10 figure

Study of pharmacokinetics and tissue distribution of liposomal brucine for dermal administration

Bai-Can Yang1, Zhi-Feng Chu1, Sha Zhu1, Li-Jun Wang1, Yu-Hong Feng1, Feng-Hua Li1, Chang-Sheng Liu2, Yuan Yuan21Pharmacy Department of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People&amp;rsquo;s Republic of China; 2Key Laboratory for Ultrafine Materials of Ministry of Education, and Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People&amp;rsquo;s Republic of ChinaObjective: To evaluate the pharmacokinetics and tissue distribution of liposomal brucine (LB) for dermal application.Methods: Pharmacokinetics and tissue distribution were studied by in vivo animal testing. High performance liquid chromatography (HPLC) was used to detect the concentration of brucine in rats&amp;rsquo; skin, plasma and various tissues.Results: After dermal administration, LB was absorbed rapidly in the skin and could be detected after 0.5 hours. After 36 hours, levels were too low to be detected. In plasma, levels were also too low to be detected after 36 hours. The concentration of LB reached 50% of the maximum in all tissues except the brain, peaking after 1.5 hours but still detectable after 12 hours.Conclusion: The concentration of LB was high in skin at the application site. LB was quickly absorbed into tissues through the blood circulation and widely distributed throughout the whole body. There was no obvious toxicity and LB did not readily accumulate in tissues and organs. It showed local potency but low overall systemic toxicity.Keywords: liposomal brucine, dermal administration, pharmacokinetics, tissue distributio

Effect of total flavones of buckwheat flowers and leaves on protein tyrosine phosphatase 1B expression in type 2 diabetic rats

The total flavone content was obtained from flowers and leaf of buckwheat (Fagopyrum esculentum Moench) by heating reflux method. The effects of the total flavone extract on the protein tyrosine phosphatase 1B (PTP1B) expression in type 2 diabetic rats were evaluated by immunofluorescence, western blotting and real-time quantitative PCR. The results suggested that the total flavone fraction from buckwheat flowers and leaves can significantly decrease the PTP1B expression in liver.Colegio de Farmacéuticos de la Provincia de Buenos Aire