Acido solfidrico nella letteratura internazionale

The reporting of ammonia (NH) and hydrogen sulfide (HS) emissions from dairies to the federal government depends on the magnitude of the emissions. However, little is known about their daily NH and HS emissions and what influences those emissions. Emissions of NH and HS from two manure storage basins at a 4400-head western free-stall dairy were measured intermittently over 2 yr. Each basin went through stages of filling, drying, and then removal of the manure during the study period. Emissions were determined using backward Lagrangian Stochastic and vertical radial plume methods. Ammonia emissions ranged from 35 to 59 kg d in one basin and from 86 to 90 kg d in a second basin, corresponding to a range of 7 to 19 g d head. Basin NH emissions were highest during initial filling and when the manure was removed. Mean HS emissions ranged from 5 to 22 kg d (1.1-4.6 g d head). Basin HS emissions were highest when the basin was filling. Crusting of the basin surface reduced NH but not HS emissions. The cessation of basin filling reduced HS but not NH emissions. Air temperature and wind conditions were correlated with NH emissions. Barometric pressure decreases were correlated with episodic HS emissions. The variability in emissions with stage of manure handling and storage and meteorological conditions indicates that determining the maximum daily emissions and the annual emissions from such waste basins requires consideration of each stage in conjunction with the climatic conditions during the stage (27) Duan XC, Guo R, Liu SY, Xiao L, Xue HM, Guo Q, et al. Gene transfer of cystathionine beta-synthase into RVLM increases hydrogen sulfide-mediated suppression of sympathetic outflow via KATP channel in normotensive rats. Am J Physiol Heart Circ Physiol 2015 Jan 16;ajpheart. Abstract: Hydrogen sulfide (H2S) has been shown to have a sympathoinhibitory effect in the rostral ventrolateral medulla (RVLM). The present study examined the function of cystathionine-beta-synthase (CBS)/H2S system in the RVLM which plays a crucial role in the control of blood pressure and sympathetic nerve activity. Adenovirus vectors encoding CBS (AdCBS) or enhanced green fl uorescent protein (AdEGFP) were transfected into the RVLM in normotensive rats. Identical microinjection of AdCBS into the RVLM had no effect on systolic blood pressure and heart rate (HR) in conscious rats. Acute experiments were performed at day 7 after gene transfer in anesthetized rats. Microinjection of the CBS inhibitors, hydroxylamine (HA) or amino-oxyacetate, into the RVLM produced an increase in the renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP) and HR. There was a potentiation of the increases in RSNA, MAP, and HR due to the CBS inhibitors in AdCBS injected rats compared to AdEGFP injected rats. Pretreatment with pinacidil, a KATP channel activator, abolished the effects of HA in two groups. Microinjection of glibenclamide, a KATP channel blocker, produced increases in RSNA, MAP, and HR in AdCBS injected rats. No changes in behavior were observed in AdEGFP injected rats. Furthermore, Western blot analysis indicated an increase in the expression of SUR2 and Kir6.1 in AdCBS injected rats. These results suggest that the increase in KATP channels in the RVLM may be responsible for the greater sympathetic out fl ow and pressor effect of HA in AdCBS injected rats compared to AdEGFP injected rats (28) Liu Y, Wu C, Zhou X, Zhu DZ, Shi H. Sulfide elimination by intermittent nitrate dosing in sewer sediments. J Environ Sci (China) 2015 Jan 1;27:259-65. Abstract: The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards, and requires expensive programs for its prevention. The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments. The study was carried out based on lab-scale experiments and batch tests using real sewer sediments. The intermittent nitrate dosing mode and the optimal control condition were investigated. The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment. The oxidation-reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S (nitrate/sulfide) ratio with slight excess nitrate is necessary for