The role of signaling pathways including the mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinase (PI3K) during viral infection has gained much recent attention. Our laboratory reported on an important regulatory role for extracellular signal-regulated kinases (ERK1/2), subfamily members of the MAPKs, during coxsackievirus B3 (CVB3) infection. However, the role of the PI3K pathway in CVB3 infection has not been well characterized. CVB3 is the most common known viral infectant of heart muscle that directly injures and kills infected cardiac myocytes during the myocarditic process. In the present study, we investi-

Understanding mulching influences on nitrogen (N) activities in soil is important for developing N management strategies in dryland. A 3 year field experiment was conducted in the Loess Plateau of China to investigate the effects of mulching, N fertilizer application rate and plant density on winter wheat yield, N uptake by wheat and residual soil nitrate in a winter wheat-fallow system. The split plot design included four mulching methods (CK, no mulch; SM, straw mulch; FM, plastic film mulch; CM, combined mulch with plastic film and straw) as main plot treatments. Three N fertilizer rates (N0, 0 kg N ha -1 ; N120, 120 kg N ha -1 ; N240, 240 kg N ha -1 ) were sub-plot treatments and two wheat sowing densities (LD, low density, seeding rate = 180 kg ha -1 ; HD, high density, seeding rate = 225 kg ha -1 ) were sub-subplot treatments. The results showed that wheat yield, N uptake, and N use efficiency (NUE) were higher for FM and CM compared to CK. However, soil nitrate-N contents in the 0-200 cm soil profile were also higher for FM and CM compared to CK after the 3 year experiment. Wheat grain yields were higher for SM compared to CK only when high levels of nitrogen or high planting density were applied. Mulching did not have a significant effect on wheat yield, nitrogen uptake and NUE when soil water content at planting was much high. Wheat yield, N uptake, and residual nitrate in 0-200 cm were significantly higher for N240 compared to N120 and N0. Wheat yield and N uptake were also significantly higher for HD compared to LD. When 0 or 120 kg N ha -1 was applied, HD had more residual nitrate than LD while the reverse was true when 240 kg N ha -1 was applied. After 3 years, residual nitrate-N in 0-200 cm soil averaged 170 kg ha -1 , which was equivalent to *40% of the total N uptake by wheat in the three growing seasons.

A series of methane adsorption-desorption isotherm experiments on anthracite of No. 3 Sihe coal mine were conducted at 20˚C, 25˚C, 30˚C, 35˚C and 40˚C respectively. Based on Clausius-Clapeyron equation, isosteric heat of adsorption and maximum heat of adsorption has been calculated. These calculations indicate that the maximum heat of adsorption in process of elevated pressure (adsorption) and lowered stress (desorption) is 23.31 KJ/mol and 24.02 KJ/mol, so it belongs to physical adsorption. However, the latter is higher than the former. From the point of view of thermodynamics, in the adsorption-desorption equilibrium system, dropping pressure alone does not lead to desorption, but it improves adsorption of water vapor molecules on the surface of the coal pores. The adsorption heat of water vapor molecules is greater than 40 KJ/mol, so the methane on the surface of coal pores will be easily replaced by water vapor, and the desorption of methane occurs eventually. Thus, the gas production in coalbed methane well by pressure reduction is consistent with the negative pressure for gas extraction.