First-Principles Study of χ3-Borophene as a Candidate for Gas Sensing and the Removal of Harmful Gases.

The potential application of borophene as a sensing material for gas-sensing devices is investigated in this work. We utilize density functional theory (DFT) to systematically study the adsorption mechanism and sensing performance of χ3-borophene to search for high-sensitivity sensors for minor pollutant gases. We compare the results to those for two Pmmn borophenes. The first-principles calculations are used to analyze the sensing performance of the three different borophenes (2 Pmmn borophene, 8 Pmmn borophene, and χ3-borophene) on five leading harmful gases (CO, NH3, SO2, H2S, and NO2). The adsorption configuration, adsorption energy, and electronic properties of χ3-borophene are investigated. Our results indicate that the mechanism of adsorption on χ3-borophene is chemisorption for NO2 and physisorption for SO2 and H2S. The mode of adsorption of CO and NH3 on χ3-borophene can be both physisorption and chemisorption, depending on the initially selected sites. Analyses of the charge transfer and density of states show that χ3-borophene is selective toward the adsorption of harmful gases and that N and O atoms form covalent bonds when chemisorbed on the surface of χ3-borophene. An interesting phenomenon is that when 8 Pmmn borophene adsorbs SO2, the gas molecules are dismembered and strongly adsorb on the surface of 8 Pmmn borophene, which provides a way of generating O2 while adsorbing harmful substances. Overall, the results of this work demonstrate the potential applications of borophene as a sensing material for harmful gas sensing or removal.

Arsenene as a promising sensor for the detection of H2S: a first-principles study.

To explore the feasibility of arsenene in detecting H2S gas, we employ the density-functional theory to investigate the geometry, electronic structure and magnetic properties of defected and doped arsenene. Point defects do not appreciably improve the sensing performance of arsenene due to small adsorption energies and charge transfer. The doping of transition metals (Ti, V, Cr, Mn, Co and Ni) introduces magnetic moments and narrows the band gap of arsenene. Transition metal (TM) dopants can enhance the interaction between H2S and a modified arsenene substrate. Adsorption energies and charge transfers increase significantly, and the adsorption converts to chemisorption. After adsorption, the Ti and Cr-doped system's band gap change is twice that of the pristine and defective arsenene. The adsorption of H2S changes the system properties of two TM-doped arsenenes: Ti-doped arsenene transforms from semiconductor to half-metal, and Ni-doped arsenene transforms from half-metal to conductor. Electrical signals can be observed in this process to detect H2S molecules. Our calculations show that doping improves the detecting performance of arsenene to H2S molecules more efficiently than defects. Our results indicate that arsenene has a promising future in developing H2S gas sensors.

Distributed Formation Control: Asymptotic Stabilization Results Under Local Noisy Information.

This paper studies the relative-position-based reference-frame-free formation control in the plane for discrete-time multiagent systems under both measurement and communication noises. To achieve the desired formation, a robust distributed orientation estimate algorithm and a robust distributed formation control law are designed. The main idea of our method is to use the historical measurement information to get unbiased estimates and use the stochastic approximation method to inhibit the noise. Under mild assumptions on the measurement/communication noises and agents' initial orientation angles, we show that a common reference frame can be asymptotically shared by all agents and the desired formation can be asymptotically stabilized almost surely under the designed distributed control law, if and only if the magnitude of the bearing measurement noise is less than ( π / 4) , the communication and distance sensing topology is rooted and the corresponding bearing sensing topology is connected. Simulations are conducted to verify the correctness and effectiveness of our orientation estimate algorithm and formation control law.

Abinukitrine A, a unique 17,18-cyclolanostane triterpenoid from Abies nukiangensis.

Abinukitrine A (1), a novel triterpenoid, was isolated from Abies nukiangensis. Comprehensive spectroscopic analysis revealed that 1 is the first example of 17,18-cyclolanostane bearing a unique 6/6/6/5/3 ring system. Its absolute configuration was unequivocally assigned by Cu-Kα X-ray single-crystallography. Compound 1 showed a potent anti-hepatitis C virus (HCV) effect.

[Clinical analysis of retinoic acid syndrome developed in 11 patients with acute promyelocytic leukemia].

To explore the clinical features, risk factors an d treatment of retinoic acid syndrome (RAS) in patients with acute promyelocytic leukemia (APL) treated with retinoic acid, the clinical and laboratory data of 11 APL patients with RAS were retrospectively analysed. The results showed that earlier and more common symptoms of RAS were successively dyspnea (11/11), fever (10/11) and hydrothorax (6/11). Higher WBC count (> or = 15.0 x 10(9)/L) in the course of treatment of all-trans retinoic acid susceptible to develop RAS (9/11). The RAS patients were treated with dexamethasone without discontinuing the treatment of retinoic acid, complete remission was achieved in 10 cases and one patient died from disseminated intravascular coagulation. It is concluded that the identification and dexamethasone treatment of RAS in earlier period are extremely important for obtaining better clinical curative effect, and it does not influence therapeutic effect of continuing application of retinoic acid.