Excitonic optical properties in monolayer SnP_(2)S_(6)

Quantum confinement effect and reduced dielectric screening in two-dimensional(2D)dramatically enhance theelectron-hole interactions.In this work,we use many-body perturbation theory and Bethe-Salpeter equation(BSE)toinvestigate the electronic and excitonic optical properties of monolayer SnP_(2)S_(6).Our findings reveal that the excitoniceffect dominates the optical absorption spectra in the visible light range,and the lowest-energy exciton X0 in monolayerSnP_(2)S_(6)is optically bright with the binding energy of 0.87 eV and the radiative lifetime of~10^(-11)s,which is highly advantageousto the photo-luminescence.Most importantly,the absence of optically forbidden states below the bright statesX0 would give rise to a high quantum efficiency of 2D SnP_(2)S_(6).We also find that applied biaxial strain can further shortenthe radiative lifetime of the bright states.These results imply that 2D SnP_(2)S_(6)is a promising candidate for the optoelectronicdevices.

Strain tunable excitonic optical properties in monolayer Ga_(2)O_(3)

Two-dimensional(2D)Ga_(2)O_(3)has been confirmed to be a stable structure with five atomic layer thickness configuration.In this work,we study the quasi-particle electronic band structures and then access the excitonic optical properties through solving the Bethe-Salpeter equation(BSE).The results reveal that the exciton dominates the optical absorption in the visible light region with the binding energy as large as~1.0 eV,which is highly stable at room temperature.Importantly,both the dominant absorption P_(1)and P_(2)peaks are optically bright without dark exciton between them,and thus is favorable for luminescence process.The calculated radiative lifetime of the lowest-energy exciton is 2.0×10^(-11)s at 0 K.Furthermore,the radiative lifetime under+4%tensile strain is one order of magnitude shorter than that of the strainfree case,while it is less insensitive under the compressive strain.Our findings set the stage for future theoretical and experimental investigation on monolayer Ga_(2)O_(3).

Neuroprotective effect of bispectral index-guided fast-track anesthesia using sevoflurane combined with dexmedetomidine for intracranial aneurysm embolization

Dexmedetomidine has sedative, anxiolytic, analgesic, anti-sympathetic, and anti-shivering effects. Dexmedetomidine might be effective in combination with sevoflurane for anesthesia, but prospective randomized controlled clinical trials with which to verify this hypothesis are lacking. In total, 120 patients who underwent embolization of an intracranial aneurysm were recruited from Anhui Provincial Hospital and Renmin Hospital of Wuhan University of China and randomly allocated to two groups. After intraoperative administration of 2% to 3% sevoflurane inhalation, one group of patients received pump-controlled intravenous injection of 1.0 ~tg/kg dexmedetomidine for 15 minutes followed by maintenance with 0.3 ~tg/kg/h until the end of surgery; the other group of patients only underwent pump-controlled infusion of saline. Bispectral index monitoring revealed that dexmedetomidine-assisted anesthesia can shorten the recovery time of spon- taneous breathing, time to eye opening, and time to laryngeal mask removal. Before anesthetic induction and immediately after laryngeal mask airway removal, the glucose and lactate levels were low, the S100~ and neuron-specific enolase levels were low, the perioperative blood pressure and heart rate were stable, and postoperative delirium was minimal. These findings indicate that dexmedetomidine can effectively assist sevoflurane for anesthesia during surgical embolization of intracranial aneurysms, shorten the time to consciousness and extubation, reduce the stress response and energy metabolism, stabilize hemodynamic parameters, and reduce adverse reactions, thereby reducing the damage to the central nervous system. This trial was registered at the Chinese Clinical Trial Registry （http：//www.chictr.org. cn/） （registration number： ChiCTR-IPR- 16008113）.

Altering elastic-plastic mechanical response of a series of isostructural metal-organic complex crystals

The mechanically compliant single crystals have attracted massive attention.However,the related reports on the single crystals composed of metal-organic complexes remain scarce.In this study,we synthesized a series of isostructural single crystals of Zn^(Ⅱ) complexes that manifest mechanical bending in response to external stress.In these crystals,the mechanical responses can be shifted between elastic bending and plastic bending by the control of the intermolecular interactions through a rational structural modification in the substituent group of pyridine ligands.As the molecular reorientation corresponding to ligand variation elongates the interfacial distance between molecular slip planes,and the structural disorder of ligands disperses the interplanar intermolecular interactions,the shift from elastic bending to plastic bending of the metal-organic complex-based single crystal was realized.The different mechanical responses of single crystals were comprehensively investigated both experimentally and theoretically.