[Spatial-temporal variations of vegetation coverage and its driving force in Inner Mongolia grassland, China]. / å† è’™å¤è‰åŽŸåŒºæ¤è¢«è¦†ç›–åº¦æ—¶ç©ºæ¼”å˜åŠå ¶é©±åŠ¨åŠ›.

Inner Mongolia grassland is rich in natural vegetation and mineral resources. Based on Landsat5/7/8 NDVI data, we used pixel binary model to invert vegetation coverage of Inner Mongolia grassland area, investigated the stability, spatial distribution, and future evolution trend of vegetation coverage by using Sen+MK and Hurst index, and analyzed the driving factors of the spatial differentiation of vegetation coverage by the optimal parameters-based geographical detector. The results showed that vegetation coverage of Inner Mongolia grassland showed an increasing trend from 2006 to 2020, and the overall spatial pattern was high in the east and low in the west, mainly with great fluctuation. The regions with slight or obvious improvement characteristics (64.8%) were much more than those with slight or severe degradation characteristics (23.2%). Compared with that in the past 15 years, the proportion of degraded vegetation in the future is expected to increase to 36.6%. The central part of Xilin Gol League and Wulanqab in the central grassland area, the western part of Hulunbuir and Erdos in the eastern grassland area, and Wuhai in the western grassland area were at the risk of degradation, which should be paid more attention. Precipitation was the dominant factor of spatial differentiation in Inner Mongolia grassland, while soil type, land use, and air temperature had the most significant synergistic effect.

[Understory plant diversity and soil physicochemical properties of Pinus tabuliformis artificial water conservation forests in the upper reaches of Miyun Reservoir, China]. / å¯†äº‘æ°´åº“ä¸Šæ¸¸æ²¹æ¾äººå·¥æ°´æºæ¶µå »æž—æž—ä¸‹æ¤ç‰©å¤šæ ·æ€§ä¸ŽåœŸå£¤ç†åŒ–ç‰¹æ€§.

We examined the characteristics of understory plant diversity and physicochemical properties and analyzed the correlation between understory plant diversity and soil factors across four Pinus tabuliformis artificial water conservation forests (P. tabuliformis × Larix gmelinii plantation, P. tabuliformis × Quercus mongolica plantation, P. tabuliformis × Armeniaca sibirica plantation, and P. tabuliformis plantation) in Fengning County, upstream of Miyun reservoir. The results showed that the composition and structure of understory community of the four forests were significantly different. The understory community in the P. tabuliformis × A. sibirica plantation was the richest in species composition, with Spiraea salicifolia, Ostryopsis davidiana, and Carex lanceolata as the main dominant species. In terms of species richness, Simpson index, Shannon diversity index, and Pielou index, plant diversity in the P. tabuliformis × A. sibirica plantation was the highest. Species diversity in the shrub layer and the herb layer was the highest in the P. tabuliformis × Q. mongolica plantation and the P. tabuliformis × Q. mongolica plantation, respectively. All physical and chemical indicators except total phosphorus differed significantly among the four forests. Soil physical and chemical properties of the P. tabuliformis × A. sibirica plantation were the best overall, and that in the P. tabuliformis × Q. mongolica plantation was the worst. Soil capillary porosity, pH, and organic matter were the main factors affecting species diversity in the shrub layer, while soil pH and capillary moisture capacity were the main factors affecting plant species diversity in the herb layer. The construction of P. tabuliformis × A. sibirica plantation was more conducive to increasing the diversity of understory plants and promoting soil improvement. Soil pH, organic matter, capillary porosity, and capillary moisture capacity were the dominant soil factors affecting the diversity of understory plants in the study area.

[Characteristics and Source Apportionment of Dustfall Pollution in the Coal Mine Area and Surrounding Areas of Wuhai City in Spring].

To study the concentration levels, pollution characteristics of each functional area, and sources of pollutants of the dust heavy metals Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Ni, Pb, Sb, Ti, V, and Zn in spring in Wuhai, 43 groups of dust samples were collected from different locations within the city from March to June 2018. The heavy metal mass concentration was then measured using an inductively coupled plasma optical emission spectrometer (ICP-OES). The results showed that:①The average contents of As, Cd, Cu, Pb, Cr, Ni, Sb, and Zn were 408.78, 1.97, 27.40, 38.93, 45.97, 25.41, 2.71, and 277.76 mg·kg-1, respectively, which were higher than the background values of the element soil. ②Only 5 of the 18 elements had significant differences in individual intervals, and the 18 elements had similar enrichment characteristics in 5 functional areas. This meant that the heavy metal pollution of dustfall in various functional areas of Wuhai was similar. ③As, Cd, Cr, and Pb elements were key pollution factors, and their comprehensive pollution indexes were 3.332, 2.622, 1.369, and 0.523, respectively, with As and Cd as primary factors. ④Through the analysis of pollution sources, it was found that in the Wuhai area the atmospheric dustfall was mainly caused by industrial emissions, coal burning, traffic dust, and coal mining and transportation. Factor analysis and multiple linear regression showed that coal was the main source of Cd pollution, with coal mining and transportation and industrial emissions accounting for 77.58% and 22.42%, respectively. The sources of As were complex, with 18.99% from industrial emissions, 15.87% from coal burning, and 6.79% from unknown sources.

[Spatial variability of surface soil nutrients in the landslide area of Beichuan County, South- west China, after 5 · 12 Wenchuan Earthquake].

Based on grid sampling and laboratory analysis, spatial variability of surface soil nutrients was analyzed with GS⁺ and other statistics methods on the landslide area of Fenghuang Mountain, Leigu Town, Beichuan County. The results showed that except for high variability of available phosphorus, other soil nutrients exhibited moderate variability. The ratios of nugget to sill of the soil available phosphorus and soil organic carbon were 27.9% and 28.8%, respectively, showing moderate spatial correlation, while the ratios of nugget to sill of the total nitrogen (20.0%), total phosphorus (24.3%), total potassium (11.1%), available nitrogen (11.2%), and available potassium (22.7%) suggested strong spatial correlation. The total phosphorus had the maximum range (1232.7 m), followed by available nitrogen (541.27 m), total nitrogen (468.35 m), total potassium (136.0 m), available potassium (128.7 m), available phosphorus (116.6 m), and soil organic carbon (93.5 m). Soil nutrients had no significant variation with the increase of altitude, but gradually increased from the landslide area, the transition area, to the little-impacted area. The total and available phosphorus contents of the landslide area decreased by 10.3% and 79.7% compared to that of the little-impacted area, respectively. The soil nutrient contents in the transition area accounted for 31.1%-87.2% of that of the little-impacted area, with the nant reason for the spatial variability of surface soil nutrients.

[Effect of heme oxugenase-1 on delayed xenograft rejection: experiment of guinea pig-to-rat liver xenotransplantation].

OBJECTIVE: To investigate the effects and mechanism of heme oxygenase-1 (HO-1) in liver xenotransplantation and mechanism thereof. METHODS: Thirty male guinea-pigs used as donors were injected intravenously with cobra venom factor (CVF) and then randomly divided into 3 groups 24 hours after: Group A injected intraperineally with NaCl, Group B injected intraperineally with cobalt-protoporphyrin (CoPP), heme oxygenase-1 inducer, and Group C injected intraperineally with CoPP and zinc protoporphyrin (ZnPP), HO-1 inhibitor zinc before their livers were harvested. Thirty male SD rats used as recipients underwent the above-mentioned treatment 24 hours before receiving the xenografts. Five pairs of guinea pigs and rats in each group underwent collection of blood and liver tissues 3 hours after the recovery of blood perfusion in the transplanted livers for detection of serum enzymes by biochemical methods and expression of HO-1 mRNA and protein in the transplanted livers by RT-PCR and Western blotting respectively. The other 5 pairs in each group were used to observe the survival time. RESULTS: The survival time of Group B was 15.5 h +/- 3.8 h, significantly longer than those of Group A (7.3 h +/- 2.1 h) and Group C (6.7 h +/- 2.9 h, both P < 0.01). The values of ALT and LDH of Group B were significantly lower than those of Group A and C (all P < 0.05). HOI-1 mRNA expression was not detected or only expressed in trace amount in the livers of normal guinea pigs, expressed in a small amount in the transplanted livers of Group A. The expression of HO-1 mRNA and that of HO-1 protein in the transplanted livers of Group B were significantly higher than those of Group A (both P < 0.01), and the expression of HO-1 mRNA and that of HO-1 protein in the transplanted livers of Group C were not significantly different from those of Group A (both P > 0.05). Remarkable NF-kB band was detected in Groups A and C, and only weak NF-kB band was seen in Group B. The E-selectin expression was significantly lower in the transplanted livers of Group B than in those of Group A and C (both P < 0.05). CONCLUSION: HO-1 delays the occurrence of delayed xenograft rejection in liver xenotransplantation. This effect depends, at least in part, on HO-1-mediated inhibition of endothelium activation in xenografts.

[Mechanisms of purified cobra venom factor in preventing hyperacute rejection following discordant liver xenotransplantation in rats].

OBJECTIVE: To investigate the mechanisms of purified cobra venom factor (CVF) in preventing hyperacute rejection (HAR) and prolonging recipient survival following discordant liver xenotransplantation in rats. METHODS: All animals were divided into two groups, group I (n = 20), unmodified recipients as control; group II (n = 20), xenograft recipients were treated with 50 microg/kg CVF i.v. on day-1. The pathologic changes of liver were observed and TNF-alpha of blood serum was detected. RESULTS: Recipient survival after CVF treatment is significantly prolonged compared with unmodified recipients (1.8 +/- 0.6 vs.7.4 +/- 2.1 h, P < 0.01). Histologically, widespread thrombosis, interstitial haemorrhage, C3 deposits on sinusoids and central veins characterized xenografts of the control group. Xenografts of the CVF group showed endothelium swelling and cellular infiltrate, no deposit of C3 was detected. CONCLUSION: Purified CVF can prevent guinea pig-to-rat liver xenografts from HAR and extend recipient survival. Preconditioning with CVF, guinea pig-to-rat combination is a useful life-supporting model to explore further mechanisms of discordant liver xenotransplantation.

[Effects of human plasminogen Kringle 5 gene therapy on pancreatic cancer].

OBJECTIVE: To investigate the effects of transfection of human plasminogen Kringle 5 gene on pancreatic cancer. METHODS: Human pancreatic cancer cells of the line PC-3 were cultured. Recombinant plasmid RINGLE 5 containing human plasminogen Kringle 5 cDNA was transfected into the PC-3 cells mediated by lipodectAMINE. RT-PCR was used to detect the expression of Kringle 5. Another 2 groups of PC3 cells: PC3 cells cultured in pure culture medium and those transfected with blank plasmids were used as controls. MTT method was used to draw the growth curves of cells. Immunohistochemistry was used to detect the expression of Kringle 5. Flow cytometry was used to observe the cell cycle and apoptosis. The morphology of cells was observed by transmission electron microscopy. Human umbilical vein endothelial cells ECV304 at logarithmic growth phase were cultured and the supernatants of the 3 groups of PC3 cells were added into the culture fluid respectively. MTT method was used to detect the absorbance and draw the growth curves. Twenty-one BALB/c nude mice were randomly divided into 3 groups of 7 mice to be inoculated with these 3 different PC3 cells. The appearance and size of tumor were observed continuously. RESULTS: Kringle 5 was expressed in the PC3 cells transfected with Kringle 5. The proliferation in the PC3 cells transfected with Kringle 5 became significantly lower compared with the other groups of PC3 cells 3 or 7 days respectively after transfection (P = 0.045 or P = 0.038). Four days after the addition of the different kinds of supernatant the ECV304 cells grew significantly slower in the Kringle 5 group than in the other 2 groups (P = 0.041). Immunohistochemistry showed high expression of Kringle 5 protein in the PC3 cells transfected with Kringle 5 and very weak expression in other 2 groups. The apoptotic indices of the PC3 cells, PC3/PUCKRINGLE 5 cells, and PC3/Kringle 5 cells were 6.6% +/- 1.3%, 7.3% +/- 0.9%, and 12.1% +/- 2.3% respectively (P = 0.045). The S stage change rates of the PC3 cells, PC3/PUCKRINGLE 5cells, and PC3/Kringle 5 cells were 33.3% +/- 3.7%, 19.4% +/- 2.4%, and 7.4% +/- 3.3% respectively. Transmission electron microscopy showed significant apoptosis in the PC3 cells transfected with Kringle 5 gene. Since the 5th week after inoculation the tumor grew significantly slower in the Kringle 5 group than in the other 2 groups (P = 0.032). Since the 7th week the tumor growth remarkably slowed down (P = 0.05). CONCLUSION: PC3 cell successfully transfected with K5 gene can potently inhibits endothelial cell proliferation and the growth of pancreatic cancer in nude mouse. The study provides a promise for the anti-angiogenesis gene therapy in vivo.