[Differences in spatial distribution of medicinal plant resources in Yinshan region of Inner Mongolia].

Yinshan Mountains stands on the southern edge of the Inner Mongolia Plateau, which stretches 1 200 km from east to west and 50 to 100 km from north to south. The rich and varied topographic environment of the Yinshan Mountains has created a variety of vegetation floras, which also makes the species of medicinal plant resources in this area unevenly distributed. Therefore, studying the spatial distribution difference of medicinal plant resources among various banners, counties, and districts in the Yinshan area is of great significance to formulate the protection policy and promote the industry development of medicinal plant. This study is based on the fourth national survey of traditional Chinese medicine resources in Inner Mongolia, regarding the results of the third national survey of traditional Chinese medicine resources. The species of medicinal plant resources in the Yinshan area around 31 banners, counties and districts were counted in detail. Then, using exploratory spatial data analysis(ESDA), trend surface analysis, spatial autocorrelation, geographical detector and other geostatistical analysis methods to analyze the differences in the spatial distribution of medicinal plant resources of the Yinshan area in Inner Mongolia. After discussing and analyzing the experimental results to account for the reasons for the overall trend of change and the degree of aggregation, the author further put forward relevant constructive suggestions. The results show that the areas with the most abundant and concentrated distribution of medicinal plant resources in the Yinshan area are located in Guyang county, Shiguai District of Baotou city, Tutou right banner, and Tuoketuo county; the higher richness and concentrated distribution of medicinal plant resources is in Wulate front banner, Wulate middle banner, Wulate back banner; areas with relatively low abundance and concentrated distribution of medicinal plant resources located in Qingshan district of Baotou city, Saihan district and Yuquan district of Hohhot city; areas with the lowest abundance and concentrated distribution of medicinal plant resources are located in Xincheng district and Huimin district of Hohhot city. It can be concluded that the horizontal distribution difference of multiple ecological factors, the special wetland environment of the river, the vertical difference of elevation, the farmland and other factors have an important influence on the richness of the medicinal plant resources species.

Sodium pheophorbide a has photoactivated fungicidal activity against Pestalotiopsis neglecta.

Sodium pheophorbide a (SPA) is a natural photosensitizer. To explore its antifungal activity and mechanism, we studied its inhibitory effects on spore germination and mycelial growth of Pestalotiopsis neglecta. We used sorbitol, 2-thiobarbituric acid (TBA) and electron microscopy to determine its effects on cell wall integrity, cell membrane lipid peroxidation and mycelial morphology. Finally, the effects of SPA on enzyme activity in mycelia were determined. The results showed that SPA effectively inhibited spore germination and mycelial growth of P. neglecta under light conditions (4000 lx, 24 h). Scanning electron microscopy (SEM) revealed that SPA treatment resulted in a roughened, twisted and knotted mycelial surface and abnormal mycelial growth. SPA influenced cell wall integrity, and the content of MDA, a cell membrane lipid peroxidation product was significantly increased (P < 0.05). SPA also significantly inhibited SOD, POD and PG activity, but enhanced PPO activity (P < 0.05). In conclusion, SPA may have potential to become a biological pesticide.

The excitation mechanism of btp2 Ir(acac) in CBP host.

Whether bis(2-(2'-benzo[4,5-α]thienyl)pyridinato-N,C3')iridium(acetylacetonate) (btp2 Ir(acac)) emission comes from carrier trapping and/or energy transfer, when doped in the 4,4'-bis(N-carbazolyl)biphenyl (CBP) host in organic light-emitting devices, is not clear; therefore, the btp2 Ir(acac) emission in CBP hosts was studied. In the red-doped device, both N,N'-bis(1-naphthyl)-N,N'-diphenyl-1.1'-bipheny1-4-4'-diamine (NPB) and (1,1'-biphenyl-4'-oxy)bis(8-hydroxy-2-methylquinolinato)-aluminum (BAlq) emission appeared, which illustrated that CBP excitons cannot be formed at two emissive layer (EML) interfaces in the device. In the co-doped devices, NPB and BAlq emissions disappear and 1,4-bis[2-(3-N-ethylcarbazoryl)vinyl]benzene (BCzVB) emission appears, illustrating the formation of CBP excitons at two EML interfaces in these devices. The reason for this difference was analyzed and it was found that holes in the NPB layer could be made directly into the CBP host in the EML interface of the red-doped device. In contrast, holes were injected into CBP host via the btp2 Ir(acac)/BCzVB dopants in the co-doped devices, which facilitated hole injection from the NPB layer to the EML, leading to the formation of CBP excitons at two EML interfaces in the co-doped devices. Therefore, btp2 Ir(acac) emission was caused by carrier trapping in the red-doped device, while, in the co-doped devices, it resulted from both carrier trapping and energy transfer from the CBP. Furthermore, it was revealed that the carrier trapping mechanism is less efficient than the energy transfer mechanism for btp2 Ir(acac) excitation in co-doped devices. In summary, our results clarified the excitation mechanism of btp2 Ir(acac) in the CBP host.

Eu2+ -induced enhancement of defect luminescence of ZnS.

The Eu2+ -induced enhancement of defect luminescence of ZnS was studied in this work. While photoluminescence (PL) spectra exhibited 460 nm and 520 nm emissions in both ZnS and ZnS:Eu nanophosphors, different excitation characteristics were shown in their photoluminescence excitation (PLE) spectra. In ZnS nanophosphors, there was no excitation signal in the PLE spectra at the excitation wavelength λex  > 337 nm (the bandgap energy 3.68 eV of ZnS); while in ZnS:Eu nanophosphors, two excitation bands appeared that were centered at 365 nm and 410 nm. Compared with ZnS nanophosphors, the 520 nm emission in the PL spectra was relatively enhanced in ZnS:Eu nanophosphors and, furthermore, in ZnS:Eu nanophosphors the 460 nm and 520 nm emissions increased more than 10 times in intensity. The reasons for these differences were analyzed. It is believed that the absorption of Eu2+ intra-ion transition and subsequent energy transfer to sulfur vacancy, led to the relative enhancement of the 520 nm emission in ZnS:Eu nanophosphors. In addition, more importantly, Eu2+ acceptor-bound excitons are formed in ZnS:Eu nanophosphors and their excited levels serve as the intermediate state of electronic relaxation, which decreases non-radiative electronic relaxation and thus increases the intensity of the 460 nm and 520 nm emission dramatically. In summary, the results in this work indicate a new mechanism for the enhancement of defect luminescence of ZnS in Eu2+ -doped ZnS nanophosphors. Copyright © 2016 John Wiley & Sons, Ltd.