Visualization of Chiral Electronic Structure and Anomalous Optical Response in a Material with Chiral Charge Density Waves.

Chiral materials have attracted significant research interests as they exhibit intriguing physical properties, such as chiral optical response, spin-momentum locking, and chiral induced spin selectivity. Recently, layered transition metal dichalcogenide 1T-TaS_{2} has been found to host a chiral charge density wave (CDW) order. Nevertheless, the physical consequences of the chiral order, for example, in electronic structures and the optical properties, are yet to be explored. Here, we report the spectroscopic visualization of an emergent chiral electronic band structure in the CDW phase, characterized by windmill-shaped Fermi surfaces. We uncover a remarkable chirality-dependent circularly polarized Raman response due to the salient in-plane chiral symmetry of CDW, although the ordinary circular dichroism vanishes. Chiral Fermi surfaces and anomalous Raman responses coincide with the CDW transition, proving their lattice origin. Our Letter paves a path to manipulate the chiral electronic and optical properties in two-dimensional materials and explore applications in polarization optics and spintronics.

[Comparative analysis on amenable mortality with main non-communicable diseases in urban and rural areas in China, 2010 and 2017].

Objective: To analyze the composition and differences of amenable mortality in urban and rural areas in China, 2010 and 2017. Methods: With the national mortality rates in 2010 and 2017 calculated by the National Bureau of Statistics and the National Health Commission as the reference, the underreporting rate from diseases was adjusted in combination with the cause-of-death surveillance data published by the Chinese Center for Disease Control and Prevention, and Center for Health Statistics and Information, National Health Commission. Age-standardized mortality was calculated by using a direct method based on the population census in 2010. Differences of the mortality in two years were compared, and the proportion of amenable mortality of different diseases in the total amenable mortality was calculated. Results: In 2010 and 2017, the age-standardized total mortality of non-communicable diseases was 536.4/100 000 and 493.6/100 000, respectively. The age-standardized amenable mortality rates were 107.6/100 000 and 96.0/100 000, respectively. Compared with 2010, the mortality of four major non-communicable diseases declined in 2017. The fastest declined amenable mortality was in with an average annual growth rate of -5.6%, followed by chronic respiratory diseases (-2.5%). Among the 11 subdivided non-communicable diseases, the age-standardized mortality of hypertension, chronic rheumatic heart disease and cerebrovascular disease declined, with an average annual growth rate of -6.7%, -5.8% and -3.0%, respectively. The proportion of amenable mortality from cerebrovascular disease was the highest among the 11 subdivided non-communicable diseases in 2010 and 2017, from 52.4% to 47.2%, followed by ischemic heart disease with an increase from 27.4% to 34.5%. Conclusion: Compared with that in 2010, the amenable mortality of non-communicable chronic diseases in urban and rural areas in China declined in 2017, of which cerebrovascular disease and ischemic heart disease account for more than 80%.

Single Dirac cone topological surface state and unusual thermoelectric property of compounds from a new topological insulator family.

Angle resolved photoemission spectroscopy study on TlBiTe2 and TlBiSe2 from a thallium-based ternary chalcogenides family revealed a single surface Dirac cone at the center of the Brillouin zone for both compounds. For TlBiSe2, the large bulk gap (∼200 meV) makes it a topological insulator with better mechanical properties than the previous binary 3D topological insualtor family. For TlBiTe2, the observed negative bulk gap indicates it as a semimetal, instead of a narrow-gap semiconductor as conventionally believed; this semimetality naturally explains its mysteriously small thermoelectric figure of merit comparing to other compounds in the family. Finally, the unique band structures of TlBiTe2 also suggest it as a candidate for topological superconductors.

Topological Lifshitz transitions and Fermi arc manipulation in Weyl semimetal NbAs.

Surface Fermi arcs (SFAs), the unique open Fermi-surfaces (FSs) discovered recently in topological Weyl semimetals (TWSs), are unlike closed FSs in conventional materials and can give rise to many exotic phenomena, such as anomalous SFA-mediated quantum oscillations, chiral magnetic effects, three-dimensional quantum Hall effect, non-local voltage generation and anomalous electromagnetic wave transmission. Here, by using in-situ surface decoration, we demonstrate successful manipulation of the shape, size and even the connections of SFAs in a model TWS, NbAs, and observe their evolution that leads to an unusual topological Lifshitz transition not caused by the change of the carrier concentration. The phase transition teleports the SFAs between different parts of the surface Brillouin zone. Despite the dramatic surface evolution, the existence of SFAs is robust and each SFA remains tied to a pair of Weyl points of opposite chirality, as dictated by the bulk topology.

[Application of nasolabial fold wrapped perforator flap in one-stage repairof nasal alar full-thickness defects after tumor resection].

Objective:To explore the application of nasolabial fold wrapped perforator flap in one-stage repair of nasal alar full-thickness defects after external nasal tumor resection.Method:Fifteen csaes of alar full-thickness defects after external nasal tumor resection were repaired with the nasolabial fold wrapped perforator flaps in a one-stage procedure. We detected the blood vessel distribution and exit of the blood vessel with Doppler Ultrasonography before these surgeries，and designed the nasolabial fold wrapped perforator flap according to the area and size of nasal alar defects． The flap with reasonable thickness was able to repair the both sides of defect after being trimmed properly. Meanwhile，the flap could be folded to form a local flap covered or lined with skin. We rotated and transferred the flap to repair nasal alar defect． Result:All the flaps survived and all donor sites healed primarily．After 3 to 36 months of follow-up,the color，texture and thickness of the flaps was similar to those of recipient sites．The scar in donor site was minor．There was little scab skin in the nasal cavity. The cosmetic results was satisfactory. Conclusion:The nasolabial fold wrapped perforator flap has the advantages of reliable blood supply,long pedicle flap,proper thickness,outside the skin and the inner lining. The cosmetic appearance of nose is satisfactory.There was little scab skin in the nasal cavity. Also the sensory function of the external nose was retained. The nasolabial fold wrapped perforator flap technique provides an ideal reconstructive option for the nasal alar full-thickness defect repair at one-stage after tumor resection.

Signature of type-II Weyl semimetal phase in MoTe2.

Topological Weyl semimetal (TWS), a new state of quantum matter, has sparked enormous research interest recently. Possessing unique Weyl fermions in the bulk and Fermi arcs on the surface, TWSs offer a rare platform for realizing many exotic physical phenomena. TWSs can be classified into type-I that respect Lorentz symmetry and type-II that do not. Here, we directly visualize the electronic structure of MoTe2, a recently proposed type-II TWS. Using angle-resolved photoemission spectroscopy (ARPES), we unravel the unique surface Fermi arcs, in good agreement with our ab initio calculations that have nontrivial topological nature. Our work not only leads to new understandings of the unusual properties discovered in this family of compounds, but also allows for the further exploration of exotic properties and practical applications of type-II TWSs, as well as the interplay between superconductivity (MoTe2 was discovered to be superconducting recently) and their topological order.

Magnetic and superconducting phase diagram of the half-Heusler topological semimetal HoPdBi.

We report a study of the magnetic and electronic properties of the non-centrosymmetric half-Heusler antiferromagnet HoPdBi (TN = 2.0 K). Magnetotransport measurements show HoPdBi has a semimetallic behavior with a carrier concentration n = 3.7 × 10(18) cm(-3) extracted from the Shubnikov-de Haas effect. The magnetic phase diagram in the field-temperature plane has been determined by transport, magnetization, and thermal expansion measurements: magnetic order is suppressed at BM ~ 3.6 T for T --> 0. Superconductivity with Tc ~ 1.9 K is found in the antiferromagnetic phase. Ac-susceptibility measurements provide solid evidence for bulk superconductivity below Tc = 0.75 K with a screening signal close to a volume fraction of 100%. The upper critical field shows an unusual linear temperature variation with Bc2(T --> 0) = 1.1 T. We also report electronic structure calculations that classify HoPdBi as a new topological semimetal, with a non-trivial band inversion of 0.25 eV.