Modification of Klein's wet ashing procedure for determination of mercury

An investigation of the use of HCl in Klein's method (25.108-25.115) to prevent loss of mercury during wet digestion resulted in consistently good recoveries from jowar and fish samples. Recoveries for the modified method ranged from 90.9 to 97.0% compared with 14.4 to 35.5% for the original method.     

Experimental challenge models for Johne's disease: a review and proposed international guidelines

An international committee of Johne's disease (JD) researchers was convened to develop guidelines for JD challenge studies in multiple animal species. The intent was to develop and propose international standard guidelines for models based on animal species that would gain acceptance worldwide. Parameters essential for the development of long-term and short-term infection models were outlined and harmonized to provide a "best fit" JD challenge model for cattle, goats, sheep, cervids, and mice. These models will be useful to study host-pathogen interactions, host immunity at the local and systemic level, and for evaluating vaccine candidates and therapeutics. The consensus guidelines herein list by animal species strains of Mycobacterium avium subsp. paratuberculosis used, challenge dose, dose frequency, age of challenge, route of challenge, preparation of inoculum, experimental animal selection, quality control, minimal experimental endpoints and other parameters.     

Similarities and differences of the spheroidal microstructure in Vertisols from Turkey and Israel

Vertisols formed on different parent materials from Turkey (Aslanpınarı and Begde soil series) and Israel (Akko soil series) were studied for their microstructure. The Aslanpınarı and Begde soils showed similar spheroidal microstructural development in the ABss horizons, whereas the spheres of Akko differed by being smaller and lacking granostriation. Micromorphometric analyses of the three soils revealed similar pore characteristics within and between the aggregates of the ABss horizons. Presence of the spheroidal microstructural units and increase of palygorskite and vermiculite in the ABss horizon of the Be de soil, which is in contrast with increasing smectite in the Aslanpınarı and Akko soils, links with an increase in the structural stability index and an increase in the hydraulic conductivity.     

Assessment of surface and sub-surface waterlogged areas in irrigation command areas of Bihar state using remote sensing and GIS

Satellite remote sensing coupled with Geographical Information Systems (GIS) offers an excellent alternative to conventional mapping techniques in monitoring and mapping of surface and sub-surface waterlogged areas. In the present study, pre-monsoon and post-monsoon surface waterlogged areas were delineated in all the 132 irrigation command areas of the Bihar State, India using Indian Remote Sensing (IRS-1D) Linear Imaging Self Scanning Sensor (LISS-III) data acquired during the period 2002–2003. Normalized Difference Water Index (NDWI) was used primarily to delineate surface waterlogged areas. Perennial waterlogged and seasonal waterlogged areas were identified for the study area by integrating the waterlogged areas derived for both the pre- and post-monsoon seasons under GIS environment. Results show that the total surface waterlogged area in Bihar is 628 × 10³ ha, which is 10.57% of command area (5939 × 10³ ha) and spread over 132 command areas. Perennial surface inundation covers 2.95% of the waterlogged area in all the command areas. Maximum waterlogged area is observed in Gandak command (212 × 10³ ha) followed by Eastern Kosi irrigation scheme (116 × 10³ ha) and Sone modernization scheme (82 × 10³ ha), respectively. Further, waterlogged areas induced by rise in groundwater level were also assessed spatially under GIS environment using the ground water level data pertaining to pre- and post-monsoon seasons of the year 2002–2003 which were spread all over the study area. The analysis of pre- and post-monsoon groundwater levels indicates that the area under non-critical category during pre-monsoon period was reduced from 4287 × 10³ ha (72.72% of command) to 1391 × 10³ ha (23.42%) in the post-monsoon. Area under most critical category during post-monsoon period increased from 0.083 × 10³ ha of command area in pre-monsoon period to 50 × 10³ ha. The study demonstrates utility of integration of remote sensing and GIS techniques for assessment of waterlogged areas particularly in regions where waterlogging conditions occur both due to excessive irrigation and accumulation of rain and floodwaters.     

Pedogenic and palaeoclimatic evidence from an Eemian calcrete in north‐western Sardinia (Italy)

A multidisciplinary approach was followed to study the pedogenic and palaeoclimatic information preserved in a buried palaeosol belonging to a Late Quaternary succession located along the bay of Alghero (north‐western Sardinia). The bay is dominated by a 5‐km long sandy beach‐ridge system backing an N‐S oriented lagoon system (Calich). The succession studied is characterized by basal shallow marine deposits, followed by clayey lagoon sediments and colluvial strata and capped by a relatively thick aeolianite. The research was based on pedological and sedimentological analyses, supported by optically stimulated luminescence (OSL) dating and by an in‐depth micro‐morphological study. Three main climatic pulses were highlighted during the Eemian. A wet period, with intense carbonate leaching occurred at the very beginning of the Eemian interglacial followed by very dry climatic conditions. This dry phase was long and arid enough to allow the formation of a thick calcrete hardpan, a typical feature of semi‐arid environments. The hardpan is dated at about 120 ka (kilo annum) and this dry event is tentatively associated with the late Eemian arid pulse (LEAP). The last phase of the Eemian recorded the restoration of a wetter climate. Finally, the succession indicated that even in a cooler environment, the central Mediterranean most probably maintained temperate conditions at least until the end of the MIS 5c (about 95 ka; early Würm).     

Mixed-phase oxide catalyst based on Mn-mullite (Sm, Gd)Mn2O5 for NO oxidation in diesel exhaust

Oxidation of nitric oxide (NO) for subsequent efficient reduction in selective catalytic reduction or lean NO(x) trap devices continues to be a challenge in diesel engines because of the low efficiency and high cost of the currently used platinum (Pt)-based catalysts. We show that mixed-phase oxide materials based on Mn-mullite (Sm, Gd)Mn(2)O(5) are an efficient substitute for the current commercial Pt-based catalysts. Under laboratory-simulated diesel exhaust conditions, this mixed-phase oxide material was superior to Pt in terms of cost, thermal durability, and catalytic activity for NO oxidation. This oxide material is active at temperatures as low as 120°C with conversion maxima of ~45% higher than that achieved with Pt. Density functional theory and diffuse reflectance infrared Fourier transform spectroscopy provide insights into the NO-to-NO(2) reaction mechanism on catalytically active Mn-Mn sites via the intermediate nitrate species.     

Reverse phase liquid chromatographic determination of some food additives

Liquid chromatographic methods are described for the separation and determination of non-nutritive sweeteners, namely, acesulfame, aspartame, saccharin, and dulcin; preservatives such as benzoic acid and p-hydroxybenzoic acid; and caffeine and vanillin in ready-to-serve beverages, ice candy, ice cream, squash beverage, tomato sauce, and dry beverage mix samples. These additives are separated on a muBondapak C18 column using methanol-acetic acid-water (20 + 5 + 75) as mobile phase and detected by UV absorption at 254 nm. Caffeine, vanillin, dulcin, and benzoic acid can be analyzed quickly by using a mobile phase of methanol-acetic acid-water (35 + 5 + 60). Aspartame can be separated in the presence of caffeine and vanillin by using the mobile phase pH 3 acetate buffer-methanol (95 + 5). Retention factors and minimum detectable limits are described. The percentage error and the percent relative standard deviation for 6 replicate samples ranged from 0.3 to 2.8 and from 1.64 to 3.60, respectively. Recovery of additives added to the foods named and analyzed by the direct method and by extraction ranged from 98.0 to 100.6% and from 91.6 to 101.8%, respectively. The proposed LC techniques are simple, rapid, and advantageous because all the additives can be detected in a single step, which makes it useful for the routine analysis of various food products.     

Shape and intraporosity of topsoil aggregates under maquis and pasture in the Mediteranean region

The clearing of Mediterranean maquis along with the creation of new pasture land has been an important factor of soil and land degradation in the Mediterranean region. The present research compared soil aggregates and their intraporosity in paired pasture/maquis plots in central E Sardinia (Italy), to study the impact of land use change on soil structure. Undisturbed surface horizons were sampled for thin‐section analysis. Aggregate shape was compared and intraporosity was studied for representative aggregates at different depths. Furthermore, the interaction of root activity and grazing under pasture and maquis cover was discussed. The outcomes revealed a complex interplay of trampling and root activity effects. A decrease (–44%) in total voids (regular pores), along with higher aggregate regularity, was observed under pasture in the 0–2 cm layer, and an increase (+261%) in 50–100 μm planar (elongated) pores was determined in the 2–4 cm layer, suggesting a possible surface compaction due to trampling and an increased subsurface fine root activity by the grassland vegetation.