Materials with large birefringence (Δn) are highly needed by fiber-optic isolators, whereas crystals showing strong second-order harmonic generation (SHG) are the key component for all-solid-state laser devices. Cyanurate constructed by the planar π-conjugated ring (C 3 N 3 O 3 , CY) is a class of fascinating materials exhibiting not only very large Δn (larger than that of calcite) but also strong SHG (2 times that of β-BaB 2 O 4 , BBO). Here, we report five new cyanurates (I−V) and their single-crystal structures; among them, II realizes a Δn = 0.4, the maximum in the cyanurate family, and IV realizes a d 33 = 6.69 pm/V, one of the highest values in the cyanurate family. We discover a dependence between Δn and the coplanarity of the CY rings that is explicitly described by a Boltzmann function, in which the coplanarity is defined by the dihedral angle (γ) between the CY plane and the principal optical axes XY plane. II realizes the maximum Δn due to its zero γ that indicates perfect coplanarity. Such a Δn−γ dependence also allows the Δn prediction of cyanurates. Furthermore, we uncover that the SHG intensity of cyanurates increases monotonically as the angle (θ) between the maximum hyperpolarizability (β max ) vector and the crystal 2 1 polar axis decreases. We predict the d ij to extend well beyond such a value and to maximize at θ = 0°. Our results have significant implications for the future rational design and discovery of highperformance materials of π-conjugated and other related systems.

We herein report a novel semiorganic NLO material, (C 5 H 6 ON) + (H 2 PO 4 ) − , 4HPP, showing promising excellent properties in the important solar-blind UV region where LAP and its deuterated form DLAP are the only commercialized semiorganic materials. For the first time, the 4-hydroxypyridine (4HP + , (C 5 H 6 ON) + ) cation is identified as NLO active and how to eliminate the dipole−dipole interaction to avoid the unwanted center-symmetry-trap caused by the polar-induced susceptibility is well demonstrated. Remarkably, 4HPP exhibits competitive and even better properties compared with LAP that include better thermal stability (decomposition at 166 vs 112 °C of LAP); wider transparency range (0.26−1.50 μm); very strong SHG response (3 × KDP); a suitable large birefringence (Δn cal = 0.25 vs 0.075 of LAP); and a high laser-induced damage threshold (2.2 × KDP). Firstprinciples calculations show that the π-conjugated organic (4HP) + cation governs the optical anisotropy, whereas the synergy of the organic and inorganic moieties dominates the SHG process. Our discovery points out a new path for the rational design of high performance semiorganic materials that require an acentric structure.

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Objective To study the effect of the establishment of a Chest Pain Center (CPC) on the treatment delay of ST-elevation myocardial infarction (STEMI) patients and the influencing factors of treatment delay in a large hospital in China. Methods The study subjects are 318 STEMI patients admitted between August 2016 and July 2019 to a large general hospital in Henan, China. Data were extracted from the electronic medical records after removing personal identifiable information. The interrupted time series regression was used to analyze the treatment delay of patients before and after the CPC establishment. Results After the CPC establishment, the patients’ pre-hospital and in-hospital treatment delays were significantly reduced. SO-to-FMC (Symptom Onset to First Medical Contact time) decreased by 49.237 min and D-to-B (Door to Balloon time) decreased by 21.931 min immediately after the CPC establishment. In addition, SO-to-FMC delay is significantly correlated with age, occupation, nocturnal onset, and the way to hospital. D-to-B delay is significantly associated with time from initial diagnosis to informed consent of percutaneous coronary intervention (PCI), catheterization lab activation time, and time for PCI informed consent. Conclusion The CPC significantly reduced the treatment delay of STEMI patients undergoing PCI.