Hysteresis resulting in forestry heat storage underestimation: A case study of plantation forestry in northern China.

Heat storage (Q) is an important component of the near-surface energy balance, and has been increasingly considered in recent energy balance studies. Studies have revealed that the hysteresis of heat storage was always been ignored, which leaded to the underestimation of heat storage proportion in energy balance. So, for further understanding the role of hysteresis effect in forestry heat storage, an observation experiment of heat storage in forestry of Pinus sylvestris var. mongolica Litv forestry - a common species in northern China - was conducted. Heat storage in the atmosphere beneath canopy, in the canopy biomass, and in the soil above a soil heat-flow plate were monitored continuously, to determine the distribution of stored heat, and solar radiation was simultaneously monitored to verify the hysteresis of heat storage versus radiation. Seasonal variations were separately analyzed to further clarify phenological effect on hysteresis. Correlation relationship was tested of lag time and underestimated energy versus climatic factors and physiological characteristics, for clarifying the reasons that resulting in hysteresis differences under different experimental day. The main results were as follows: (1) Hysteresis exists in heat storage and the lag time was 3.79 h in our study area; (2) The evaluation of hysteresis is crucial to avoid an underestimation of heat storage. Correction of lag time increases the heat storage proportion in R from 3.78% to 8.48%; (3) Increasing of air temperature and humility daily differences will enhance the underestimated energy. High radiation condition will weak the underestimation on heat storage and short the lag time. Soil moisture and leaf area index were not effect energy hysteresis significantly in sandy vegetation. Climatic factors were the main reason that resulting in the differences of hysteresis. This study helps to improve understanding energy transmitting in canopy and offering a new view in solving surface energy imbalance.

Application of Boundary Layer Displacement Thickness in Wind Erosion Protection Evaluation: Case Study of a Salix psammophila Sand Barrier.

Since the establishment of blown sand physics, surface roughness has been widely used in current research to indicate the ability of a surface to resist wind erosion and to evaluate the windproof effect of protective measures. However, since the calculation of surface roughness can result in different values and its applicability is poor, there are disadvantages to its use. Therefore, it is proposed that the boundary layer displacement thickness should be used rather than roughness as an indicator to solve such problems. To analyze the new indicator's accuracy and applicability when evaluating the effect of protective measures, a wind tunnel simulation experiment on a typical mechanical protection measure commonly used for sand control in China was conducted. Indicators of roughness and boundary layer displacement thickness were compared in evaluating the windproof performance of a Salix psammophila sand barrier of differing heights, side lengths, and porosities. The wind speed acceleration rate and effective protection area, which can directly reflect the protective effect of a sand barrier, were analyzed as evaluation criteria. The results show that roughness can only reflect the influence of height on the windbreak effect of sand barriers, whereas the boundary layer displacement thickness accurately showed the influence of height, side length, and porosity on the windproof effect of the sand barriers. Compared with roughness, the boundary layer displacement thickness was more strongly correlated with the effective protection area. Therefore, the boundary layer displacement thickness, rather than roughness, should be used as a new indicator when evaluating the windproof effect of protective measures.

Effect of Straw Checkerboards on Wind Proofing, Sand Fixation, and Ecological Restoration in Shifting Sandy Land.

Due to their simple layout and adaptability to various environments, straw checkerboards are widely used to control windblown sand in China. To fully understand the wind proofing and sand-fixing benefits of different board specifications, and to determine the restorative effects of straw checkerboard, we tested different sizes of checkerboard, determined their performance as a windbreak and in trapping shifting sand, and constructed models based on wind tunnel tests, enabling the wind speed flow field to be analysed. We also sampled the soil in areas where straw checkerboards had been established for several years and analysed the trends in soil physical and chemical properties over time. We found that all sizes of straw checkerboard effectively reduced the wind speed near the surface and formed a protected area, with the best protective effect achieved for a one-meter board. All sizes of straw checkerboard effectively intercepted windblown sand to form surface accumulation, with the one-meter board again showing the best performance. The use of a straw checkerboard also effectively improved the physical and chemical properties of soil and promoted ecological restoration. These results indicate that straw checkerboards are a low-cost engineering measure that could play an important role in desertification control and the ecological restoration of sandy land ecosystems.

How the Plant Temperature Links to the Air Temperature in the Desert Plant Artemisia ordosica.

Plant temperature (Tp) is an important indicator of plant health. To determine the dynamics of plant temperature and self-cooling ability of the plant, we measured Tp in Artemisia ordosica in July, in the Mu Us Desert of Northwest China. Related factors were also monitored to investigate their effects on Tp, including environmental factors, such as air temperature (Ta), relative humidity, wind speed; and physiological factors, such as leaf water potential, sap flow, and water content. The results indicate that: 1) Tp generally changes in conjunction with Ta mainly, and varies with height and among the plant organs. Tp in the young branches is most constant, while it is the most sensitive in the leaves. 2) Correlations between Tp and environmental factors show that Tp is affected mainly by Ta. 3) The self-cooling ability of the plant was effective by midday, with Tp being lower than Ta. 4) Increasing sap flow and leaf water potential showed that transpiration formed part of the mechanism that supported self-cooling. Increased in water conductance and specific heat at midday may be additional factors that contribute to plant cooling ability. Therefore, our results confirmed plant self-cooling ability. The response to high temperatures is regulated by both transpiration speed and an increase in stem water conductance. This study provides quantitative data for plant management in terms of temperature control. Moreover, our findings will assist species selection with taking plant temperature as an index.

Different toxic effect of hemin on primary cultured neurons, astrocytes and brain capillary endothelial cells / 中华神经医学杂志

Objective To investigate the toxic effect of hemin on primary cultured neurons,astrocytes,and brain capillary endothelial cells (BCECs),and the damage effect of hemin with different concentrations on the above cells. Methods (1) Primary cultured neurons,astrocytes and BCECs from the cortex of rats were exposed to different doses of hemin for 2 h,and continue culture of these cells for 24 to 96 h after withdrawing hemin was performed; the cellular morphology was examined under phase-contrast microscope; cellular survival rate was measured with Alama blue staining; and the releasing rate of lactate dehydrogenasing (LDH) was detected with regular biochemical method. (2) Primary cultured cells were exposed to different doses of hemin for 2 h,and continue culture of the cells for 4 h was performed after washing out the hemin; and then,concentrated formic acid was employed to dissociate the cells, and heme content in dissociated cells was measured with spectrophotometer. (3) Primary cultured cells was exposed to different doses ofhemin for 30,60 and 120 min,respectively,and continue culture of the cells for 4 h was performed after washing out hemin; and then,intracellular Fe3+was examined with Prussian blue staining. Results (1) Cultured neurons were injured by a low dose ofhemin (5 mmol/L) with a decreased survival rate by 40.2％ and an increased LDH releasing rate by 22.2％; and the pathological changes of cellular morphology were severe after 24 h of exposure to hemin.Following the increased doses ofhemin and time of post-exposure,the cellular death and LDH releasing were increased,and the morphological changes of cells were much severe. (2) The low and medium doses of hemin (5 mmol/L and 25 mmol/L) did not induce cellular death, LDH releasing and morphological changes in astrocytes; and a high dose ofhemin (50 mmol/L) could induce a death rate of astrocytes decreasing by 52.4％, a LDH releasing rate increasing by 31％ and obvious morphological changes of astrocytes; however, the injured astrocytes could regenerate fluent cellular monolayer 96 h after exposing to high dose of hemin treatment.(3) Hemin with either low or high dose did not induce any changes in cellular survival,LDH releasing and cellular morphology of BCECs.(4) The heme content in cultured neurons was significantly higher than that in astrocytes and BCECs after hemin treatment for 2 h.(5) The blue Fe3+ stained granules appeared in neurons as early as 30 min after neurons being exposed to hemin, and Fe3+ stained positive cells in neurons were significantly higher than those in astrocytes and BCECs at any dose ofhemin and any time point ofhemin treatment. Conclusion Hemin is highly toxic to neurons, but it can only injure astrocytes at a high dose and it can not induce direct damage in BCECs; free hemin could rapidly enter and accumulate in neurons,but less accumulate in astrocytes and not accumulate in BCECs.

Effect of Shuganlipi decoction on Th1/Th2 cytokines in patients with chronic hepatitis B / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of Shuganlipi decoction on Th1/Th2 cytokines, liver function and HBV replication in patients with chronic hepatitis B (CHB).</p><p><b>METHODS</b>Eighty-six confirmed CHB cases were randomly divided into control group (n=42) and experimental group (n=44) for treatment with routine western medication and additional treatment with Shuganlipi decoction, respectively. The production of IFN-γ, IL-2, IL-6, IL-10 and liver function, HBV DNA, and HBeAg were detected in all the patients.</p><p><b>RESULTS</b>The total response rate to the treatment was significantly higher in the experimental group than in the control group (78.13% vs 57.14%, P<0.01). ALT, AST, TBIL and ALB were all improved obviously in the two groups after the treatments (P<0.01). In terms of ALT and ALB, the experimental group showed more obvious improvement than the control group(P<0.05). The treatments also resulted in significant increases of IFN-γ and IL-2 levels and reductions of IL-6 and IL-10 levels in the two groups (P<0.01).</p><p><b>CONCLUSION</b>Shuganlipi decoction can improve the liver function and activity of Th1/Th2 cytokines to promote the clearance of liver cell HBV infection.</p>