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The biomass of a secondary evergreen and deciduous broad-leaved mixed forest was comprehensively inventoried in a permanent 2 ha plot in southwestern China. Biomass models, sub-sampling, soil pit method, and published data were utilized to determine the biomass of all components. Results showed that the total biomass of the forest was 158.1 Mg ha; the total biomass included the major aboveground (137.7 Mg ha) and belowground (20.3 Mg ha) biomass components of vascular plants as well as the minor biomass components of bryophytes (0.078 Mg ha) and lichens (0.043 Mg ha). The necromass was 17.6 Mg ha and included woody debris (9.0 Mg ha) and litter (8.6 Mg ha). The spatial pattern of the aboveground biomass was determined by the spatial distribution of dominant trees with large diameter, tall height, and dense wood. The belowground biomass differed in terms of root diameter and decreased with increasing soil depth. The belowground biomass in each soil pit in local habitats was not related to the spatial distribution of woody plants and soil pit depth. The karst forest presented lower biomass compared than the nonkarst forests in the subtropical zone. Biomass carbon in the karst terrains would increase substantially if degraded karst vegetation could be successfully restored to the forest. Comprehensive site-based biomass inventory of karst vegetation will contribute not only to provide data for benchmarking global and regional vegetation and carbon models but also for regional carbon inventory and vegetation restoration.â1â1â1â1â1â1â1â1

In view of problem that current switched reluctance drive systems are lack of friendly human machine interface to display running state of the system and set given parameters, the paper proposed a design scheme of human machine interface of switched reluctance drive system based on simplified ModBus communication protocol. It gave general structure of the switched reluctance drive system, and introduced design of serial communication circuit and communication program in the human machine interface. Debugging result shows that the human machine interface runs stably and realizes functions of friendly display and online parameters modification for the switched reluctance drive system.

Peony seed oil has been known to have a high value for health due to the high content of unsaturated fatty acid. However, few studies have investigated which factors impact the oil quality and composition of seeds in the traditional mining cultivation area. In the present study, the investigation was conducted in 30 cultural field sites. Significantly negative relationships were found between Cu content in soils or leaves and linoleic and unsaturated fatty acids. Further tests revealed that Cu evidently accumulated in leaves. This demonstrated Cu content in soils was the important factor that influenced linoleic acid content and unsaturated fatty acid content. Such proposition must be considered when cultivating groups of plant toward expanding oil production. [ABSTRACT FROM AUTHOR]

In order to localize the main organic site of alkaline toxicity to plants, the injury of NaCl or NaHCO3 to tobacco (Nicotiana tabacum L.) seedlings was compared. The results showed that the injury effect of alkaline stress on tobacco were much stronger than salt stress, with respect to growth retardation, photosynthetic inhibition, and ionic unbalance. The root/shoot ratio, transpiration rate, and Na+ accumulation in the leaves were lower than other. Further investigation of the root ultrastructure showed that the endoplasmic reticulum and nuclear membrane were not visible or absent, while more small vacuoles and mitochondria with dilated or absent cristae were observed under the 100 mM NaHCO3 stress. These results indicate that under alkaline conditions, the endomembrane system of root cells is directly and seriously damaged. This possibly causes the failure of water absorption and ion compartmentalization. [ABSTRACT FROM AUTHOR]

The failure of normal excitation or freewheeling often occurs when power converter is damaged. The fault type was then analyzed in an asymmetric half-bridge converter, applied to a 12/8 switched reluctance drive (SRD). The analytical solution of the phase winding current was obtained by formula derivation under normal and fault conditions. Detailed discussions were presented about the amplitude changes of the DC bus current and its digital analysis results under different work conditions. The short-circuit and open-circuit fault detect method of transistors was also proposed, which was connected to the voltage pulse width modulation ( PWM) signals and the DC bus current. A model was used to build the pattern of the power converter of SRD system and the simulation has been implemented with mat-lab. The short-circuit and open-circuit fault simulation result of transistors are agreement with the theoretical analysis results. The detect method can identify the fault phase and determine the fault type. As a result,it has been proved that the method is effective. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the feasibility and effect of mesenchymal stem cells (MSCs)-poly (lactic-co-glycolic acid) (PLGA) scaffold as transplant in repair of skin damage., Methods: MSCs were isolated from the bone marrow of femur of a one-month-old New Zealand rabbit, cultured, and labeled with diamidino-phenyl-indole (DAPI). Porous foam scaffolds were made with PLGA. MSCs of 2 - 3 passages were seeded on the scaffolds. Fluorescence microscopy and scanning electron microscopy were used to observe the growth of the MSCs. Six pieces of skin 2 cm x 2 cm in size were cut from the backs of five 5-month-old new Zealand rabbits and then 4 pieces of MSCs- PLGA scaffolds and 2 pieces of porous foam PLGA scaffolds of the size similar to these of the cut skin were transplanted to the skin wounds. The wound healing was observed. Five days after the operation, samples of newly-grown skin were taken to undergo HE staining, VG staining, and microscopy. Immunofluorescence histochemistry was used to detect the cytokeratin AE1/AE3., Results: Scanning electron microscopy showed that holes were distributed evenly on the surface of and inside the porous foam PLGA scaffolds Fluorescence microscopy and scanning electron microscopy showed that the MSCs grew well on the porous foam PLGA scaffolds and the number of MSCs increased gradually. Animal experiment showed that with the degradation of the polymer scaffolds the wounds were gradually covered by newly grown skin similar to the normal skin. Immunofluorescence histochemistry showed fluorescence positive cells in the stratum corneum and follicles. The wounds transplanted only with porous foam PLGA scaffolds formed new skin too, however, in the dermis of the new skin only thickened fibrous scars and a few follicles were seen., Conclusion: The compound of MSCs-PLGA polymer is effective in wound healing.