Anti-kindling effect of Ginkgo biloba leaf extract and L-carnitine in the pentylenetetrazol model of epilepsy

Environmental Science and Pollution Research - Epilepsy is one of the most common serious brain disorders, affecting about 1% of the population all over the world. Ginkgo biloba extract (GbE) and...     

Microbial degradation of livestock-generated ammonia using biofilters at typical ambient temperatures

The purpose of this research was to neutralize livestock-generated ammonia by using biofilters packed with inexpensive inorganic and organic packing material combined with multicultural microbial load at typical ambient temperatures. Peat and inorganic supporting materials were used as biofiltration matrix packed in a perfusion column through which gas was transfused. Results show the ammonia removal significantly fell in between 99 and 100% when ammonia concentration of 200 ppmv was used at different gas flow rates ranged from 0.030 to 0.060 m3 h(-1) at a fluctuating room temperature of 27.5 +/- 4.5 C (Mean +/- SD). Under these conditions, the emission concentration of ammonia that is liberated after biofiltration is less than 1 ppmv (0.707 mg m(-3)) over the period of our study, suggesting the usage of low-cost biofiltration systems for long-term function is effective at wider ranges of temperature fluctuations. The maximum (100%) ammonia removal efficiency was obtained in this biofilter was having an elimination capacity of 2.217 g m(-3) h(-1). This biofilter had high nitrification efficiencies and hence controlled ammonia levels with the reduced backpressure. The response of this biofilter to shut down and start up operation showed that the biofilm has a superior stability.     

Effects of storage method and duration on the toxicity of marine sediments to embryos of Crassostrea gigas oysters

The objective of laboratory sediment bioassays is to estimate in situ toxicity. This goal is difficult to achieve, as one of the main limitations of sediment toxicity tests is disruption of sediment geochemistry during sampling, handling and preservation. The effects of storage on the estimation of marine sediment toxicity to Crassostrea gigas embryos and larvae were investigated. Three storage methods and four storage periods were compared with three different sediment types contaminated by heavy metals, polycyclic aromatic hydrocarbons (PAHs) and both contaminants. Freezing and freeze-drying considerably increased the toxicity of decanted sediments and their elutriates as compared to the toxicity obtained with fresh sediments. Concerning the elutriates, the toxicity found with frozen and freeze-dried sediments was correlated with DOC, ammonia and PAH contents. However, the toxicity of fresh sediments kept at 4 degrees C increased with increasing duration of storage and was also correlated with the amount of ammonia in the elutriates.     

Sorption and oxic degradation of the explosive CL-20 during transport in subsurface sediments

The abiotic sorption and oxic degradation processes that control the fate of the explosive CL-20, Hexanitrohexaazaisowurtzitane, in the subsurface environment were investigated to determine the potential for vadose and groundwater contamination. Sorption of aqueous CL-20 is relatively small (K(d) = 0.02-3.83 cm3 g(-1) for 7 sediments and 12 minerals), which results in only slight retardation relative to water movement. Thus, CL-20 could move quickly through unsaturated and saturated sediments of comparable composition to groundwater, similar to the subsurface behavior of RDX. CL-20 sorption was mainly to mineral surfaces of the sediments, and the resulting isotherm was nonlinear. CL-20 abiotically degrades in oxic environments at slow rates (i.e., 10s to 100s of hours) with a wide variety of minerals, but at fast rates (i.e., minutes) in the presence of 2:1 phyllosilicate clays (hectorite, montmorillonite, nontronite), micas (biotite, illite), and specific oxides (MnO2 and the ferrous-ferric iron oxide magnetite). High concentrations of surface ferrous iron in a dithionite reduced sediment degraded CL-20 the fastest (half-life < 0.05 h), but 2:1 clays containing no structural or adsorbed ferrous iron (hectorite) could also quickly degrade CL-20 (half-life < 0.2 h). CL-20 degradation rates were slower in natural sediments (half-life 3-800 h) compared to minerals. Sediments with slow degradation rates and small sorption would exhibit the highest potential for deep subsurface migration. Products of CL-20 oxic degradation included three high molecular weight compounds and anions (nitrite and formate). The 2-3.5 moles of nitrite produced suggest CL-20 nitro-groups are degraded, and the amount of formate produced (0.2-1.2 moles) suggests the CL-20 cage structure is broken in some sediments. Identification of further degradation products and CL-20 mineralization rates is needed to fully assess the impact of these CL-20 transformation rates on the risk of CL-20 (and degradation product) subsurface movement.     

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