Association between hyperhomocysteinemia and stroke with atherosclerosis and small artery occlusion depends on homocysteine metabolism-related vitamin levels in Chinese patients with normal renal function.

This study was conducted to investigate the role of different homocysteine metabolism-related vitamin (HMRV) levels in the correlation between hyperhomocysteinemia (HHCY) and ischemic stroke (IS) subtypes. Three hundred and forty-eight IS patients manifesting different vascular subtypes were subclassified on the basis of HMRV deficiencies. Correlation between HHCY and IS subtypes was investigated in all the subgroups. In this study, HHCY was significantly correlated with the IS subtypes in large artery atherosclerosis (OR 1.126, 95%CI: 1.051 ~ 1.206, P = 0.001) and small artery occlusion (OR 1.105, 95%CI: 1.023 ~ 1.193, P = 0.012). Subgroup analysis revealed a correlation between HHCY and IS subgroup (OR 1.201, 1.178, 95%CI: 1.081 ~ 1.334, 1.058 ~ 1.313, P = 0.001, P = 0.003, respectively) in HMRV deficiency, but not significantly with the IS subgroup in normal HMRV levels. Serum vitamin B12 concentrations are inversely correlated with both IS subtypes in HMRV deficiency subgroups (OR 0.992, 0.995, 95%CI: 0.987 ~ 0.996, 0.991 ~ 0.999, P < 0.001, P = 0.007, respectively), which may contribute to HHCY incidence in these populations. The correlation between HHCY and IS subtypes is affected by HMRV levels in this case-control study. Our findings are helpful to understand the inconsistency in prior homocysteine studies. Serum vitamin B12 levels may play a critical role in HHCY incidence in this Chinese population.Cerebrovascular disease has emerged as the leading cause of disability and mortality in both urban and rural areas of China (Neurology branch of Chinese Medical Association 2015). Ischemic stroke (IS) constitutes 60% to 80% of all cerebrovascular disease (Neurology branch of Chinese Medical Association 2014). Among a variety of risk factors, hyperhomocysteinemia (HHCY) has been closely correlated with IS due to intracranial small-vessel disease and extracranial large-artery disease (Selhub et al. 1995; Eikelboom et al. 2000; Alvarez et al. 2012; Jeon et al. 2014). However, the failure to lower homocysteine (HCY) via homocysteine metabolism-related vitamin (HMRV, including folic acid and vitamin B12 but not vitamin B6 in this study) supplementation to reduce stroke morbidity questions the role of HCY as a risk factor for stroke (Lonn et al. 2006; Hankey et al. 2010). Theoretically, HMRV supplementation merely lowers the incidence of stroke induced by HHCY resulting from HMRV deficiency, whereas HHCY-induced stroke concomitant with normal HMRV levels may be refractory to treatment. The correlation between HCY varying with HMRV levels and IS subtypes is still unclear. In this study, we investigated the impact of variation in HMRV levels on the correlation between HHCY and IS subtypes in 348 acute IS patients with large and small vessel diseases. We sought to determine the factors underlying the conflicting results associated with lowering HCY by HMRV supplementation to reduce stroke incidence.

[Response of Soil Respiration to Extreme Precipitation in Semi-arid Regions].

Evaluating the response of soil microbial respiration to extreme precipitation event is significant for a better understanding about the influence of the change of precipitation regime on soil carbon cycling under global warming. A simulated experiment of extreme precipitations was conducted during the rainy season (July-September 2015) in the Changwu State Key Agro-Ecological Station, Shaanxi, China. The treatments consisted of three total precipitations in rainy season (600 mm, 300 mm, and 150 mm) and two precipitation regimes (10 mm, 150 mm; P10, P150). Soil microbial respiration varied differently in the same single rainfall event among three precipitations. The variation coefficient of soil microbial respiration under 600 mm total precipitation was 36% (P150) and 33% (P10), and 28% and 22% under 300 mm total precipitation, 43% and 29% under 150 mm total precipitation. Under 600 mm total precipitation, the cumulative soil microbial respiration under P150 was 20% less than that under P10; however, the cumulative soil respiration of P150 under 150 mm total precipitation was 22% more than that under P10; and there was no significant difference between P10 and P150 under 300 mm total precipitation. Therefore, the duration in soil water stress must be considered to estimate soil microbial respirations under extreme precipitations.

[Variation of Soil CO2 Flux and Environmental Factors Across Erosion-Deposition Sites Under Simulation Experiment].

The CO2 flux from soil is an important component of global carbon cycle, and a small variation of soil CO2 flux can prominently influence atmospheric CO2 concentration and soil organic carbon stock. Soil erosion significantly influences soil CO2 emission. However, the process of soil CO2 flux during soil erosion and soil deposition remains uncertain. At the present study, a simulated experiment on soil erosion and deposition was conducted at Changwu State Key Agro-Ecological Station, Shaanxi, China. From July to September in 2014 and 2015, soil CO2 flux was periodically measured using an automated CO2 flux system LI-8100 (LI-COR, Lincoln, NE, USA) and soil temperature and moisture were collected by series data collection system of soil temperature and soil moisture (EM50, DECAGON, USA). The measurement frequency of soil CO2 flux was once a week during 09:00 and 11:00. Soil temperature and soil moisture of 10 cm topsoil were measured continuously (at an interval of 30 minutes) during the experiment. At the same time, runoff and sediment were collected as well in each rain event, and then SOC content in sediment was measured. The results showed that soil CO2 flux between erosion and deposition sites had a significant difference (P<0.05), and soil CO2 flux at deposition site [mean value 1.38 µmol·(m2·s)-1] was 31% higher than that of soil CO2 flux at deposition site [1.05 µmol·(m2·s)-1], while temperature sensitivity at deposition site (Q10:8.14) was 3 times as high as that at erosion site (2.34). Soil moisture at deposition site was 19% higher than that at erosion site (P<0.05). Soil temperature was slightly higher at erosion site. The average SOC content (7.26 g·kg-1) increased by 6% in the sediment compared with the initial SOC content (6.83 g·kg-1). Soil moisture and SOC redistribution across erosion and deposition sites were influencing factors for soil CO2 flux under erosional environment. In conclusion, soil CO2 flux showed a significant variation at erosion site and deposition site. Changes in soil moisture and SOC contributed much to the difference in soil CO2 flux across erosion and deposition sites.

[Changes of Soil Organic Carbon and Its Influencing Factors of Apple Orchards and Black Locusts in the Small Watershed of Loess Plateau, China].

Orchard and black locust are two typical plants for comprehensive control in the small watershed of land uses in Loess area. The analysis of soil carbon sequestration function changes of growing two plants is important to gain a deep understanding of soil carbon cycle process and its influencing factors of terrestrial ecosystems under the condition of small watershed comprehensive control. The experiment was conducted in the Changwu State Key Agro-Ecological Station, Shanxi, China. SOC, TN, fine root biomass and litter amount were determined at different age apple orchards and black locusts on the slope land of Wangdonggou watershed to study the variation characteristics of soil organic carbon and its influencing factors under two measurements. The results showed that: (1) SOC and TN contents in apple orchards significantly decreased with the increased age, whereas those in black locust showed an increased tendency with the age increased. Compared with the adjacent cropland,the SOC and TN contents in year 3, year 8, year 12 and year 18 apple orchards were decreased 3. 26%, 10. 54%, 18. 08%, 22. 55% and - 8. 08%, - 0. 48%, 4. 97%, 16. 91%, respectively. However,SOC and TN contents increased 5. 31%, 32. 36%, 44. 13% and 2. 49%, 15. 75%, 24. 22%, in year 12, year 18 and year 25 black locusts, respectively. (2) The fine root biomass in year 3, year 8, year 12, and year 18 apple orchards were about 25. 97% 66. 23%, 85. 71% and 96. 10% of the adjacent cropland, respectively; and the litter amounts were all 0 g . m-2. However, compared with adjacent cropland, The fine root biomass in year 12, year 18 and year 25 black locusts were increased 23. 53%, 79. 41%, 157. 35%, respectively; and the litter input rates were 194, 298 , 433 g . (m2 . a) -1, respectively. (3) The difference of organic matter input was the major factor which drove the variability of soil carbon sequestration function of apple orchard and black locust ecosystems.

[Effects of Nitrogen Fertilization on Soil Respiration and Temperature Sensitivity in Spring Maize Field in Semi-Arid Regions on Loess Plateau].

Understanding the effects of nitrogen fertilization on soil respiration rate and its temperature sensitivity (Q10) is of critical importance to predict the variability of soil respiration in cropland. A field experiment was established in a rain-fed spring maize cropland (Zea mays L. ) in the State Key Agro-Ecological Experimental Station in the Loess Plateau in Changwu County, Shaanxi Province, China. The experiment comprised of two treatments: no N-fertilizer application ( CK) and N-fertilizer application with 160 kg N · hm(-2) (N). Soil respiration rate, soil temperature, soil moisture, yields, aboveground biomass and root biomass were measured in two continuous spring maize growing seasons from April 2013 to September 2014. The cumulative soil CO2 emissions were increased by 35% in 2013 and 54% in 2014 in N treatment as compared to CK treatment. Though nitrogen fertilization significantly increased the cumulative soil CO2 emissions (P < 0.05), it did decrease evidently the temperature sensitivity of soil respiration (P < 0.05) . The Q10 values in N treatment were decreased by 27% and 17% compared with CK treatment in 2013 and 2014, respectively. Nitrogen fertilization significantly increased the maize yields, aboveground biomass and root biomass (P < 0.05). Root biomasses in N treatment were 32% and 123% greater than those in CK treatment of 2013 and 2014, respectively. Nitrogen fertilization had no marked influence on soil temperature or moisture. Root biomass was a critical biotical factor for variation of soil respiration under nitrogen fertilization.

[Effects of different culture conditions on main chemical compositions of Anoectochilus roxburghii].

OBJECTIVE: To investigate the effects of different culture conditions on the main chemical compositions of Anoectochilus roxburghii, so as to determine the optimum culture conditions and provide theoretical support for large-scale production of Anoectochilus roxburghii. METHODS: The light qualities, photoperiods and induction periods were changed to regulate the main chemical compositions of Anoectochilus roxburghii. RESULTS: The contents of total flavonoids, quercetin, isorhamnetin and kaempferol in blue light were higher than that in yellow light, the worst was under red light. There was the highest total flavonoids, kaempferol and isorhamnetin content in photoperiod of 14 h/d. After one month inoculation, the total flavonoids, quercetin, isorhamnetin and kaempferol contents were the highest. CONCLUSION: The results show that the optimum culture condition is: inducted 15 days with blue light inoculated one month later at the photoperiod of 14 h/d.