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Fenton's reagent in its conventional form, although effective for contaminant treatment, is impractical from an in-situ field application perspective due to low pH requirements (i.e., pH 3-4), and limited reagent mobility when introduced into the subsurface. Modified Fenton's processes that use chelated-iron catalysts and stabilized hydrogen peroxide have been developed with the goal of promoting effective in-situ field application under native pH conditions (i.e., pH 5-7), while extending the longevity of hydrogen peroxide. Laboratory experiments conducted in soil columns packed with organic soil to compare modified Fenton's catalysts with conventional catalysts (acidified iron [II]) indicated superior mobility and sorption characteristics for modified Fenton's catalysts. Furthermore, the acidic pH of a conventional catalyst was buffered to the native soil range, leading to increased iron precipitation/adsorption following permeation through the soil column. The chelates present within the modified Fenton's catalyst showed greater affinity toward iron compared with the native soil and, hence, minimized iron loss through adsorption during the permeation process even at pH 5-7. Field effectiveness of the modified Fenton's process was demonstrated at a former dry-cleaning facility located in northeast Florida. Preliminary laboratory-scale experiments were conducted on soil-slurry and groundwater samples to test the process efficacy for remediation of chlorinated solvents. Based on successful experimental results that indicated a 94 percent (soil slurry) to 99 percent (groundwater) reduction of cis-1,2-DCE, PCE, and TCE, a field-scale treatment program was initiated utilizing a plurality of dual-zone direct push injection points installed in a grid fashion throughout the site. Results of treatment indicated a 72 percent reduction in total chlorinated contamination detected in the site groundwater following the first injection event; the reduction increased to 90 percent following the second injection event. © 2002 Wiley Periodicals Inc.

Understanding crop responses to climate is essential to cope with anticipated changes in temperature and precipitation. We investigated the climate–crop yield relationship and the impact of historical climate on yields of rice, maize and wheat in the Koshi basin of Nepal. The results show significant impact of growing season temperature and precipitation on crop production in the region. Rice, maize and wheat cultivated at altitudes below 1,100, 1,350 and 1,700 m amsl (above mean sea level), respectively, suffer from stress due to higher temperatures particularly during flowering and yield formation stages. Responses of crop yields to a unitary increment in growing season mean temperature vary from −6 to 16 %, −4 to 11 % and −12 to 3 % for rice, maize and wheat, respectively, depending on the location and elevation in the basin. In most parts of the basin, we observe warming trends in growing season mean temperatures of rice, maize and wheat over the last few decades with clear evidence of negative impacts on yields. However, at some high-elevation areas, positive impacts of warming are also observed on rice and maize yields. If the observed trends in temperature continue in future, the impact is likely to be mostly negative on crop production in the basin. However, crop production may gain from the warming at relatively higher altitudes provided other conditions, e.g., water availability, soil fertility, are favorable.

Laboratory, pilot, and full-scale experiments were used to evaluate and optimize the ISOTECSM remedial process at a warehousing facility in Union, New Jersey. Based on modified Fenton's oxidative chemistry, the ISOTECSM process uses a proprietary catalytic agent that delays formation of reactive hydroxyl radicals. This allows adequate dispersion of the hydroxyl radicals, which is an oxidizing agent, throughout a contaminant plume. Ground-water at the site was contaminated with high levels of gasoline and waste oil constituents, principally BTEX and MTBE. Bench scale microcosm studies were used to evaluate the appropriate site-specific stoichiometric relationships between catalyst, stabilizers, and oxidizers; the effect of contaminant type and concentration; and the pH optima. Based on results of the laboratory studies, a pilot-scale study was performed at the site. One injection point for catalyst, stabilizers, and oxidant was installed in the contaminated zone at the site, with one hydraulically connected downgradient well used for monitoring. A single treatment of the reagents in the optimal stoichiometry determined from the laboratory study was injected in-situ over a period of three days. A 98.5 percent reduction in volatile organics was observed in the area treated, with the radial extent of treatment estimated to be approximately 20 feet, based on the presence of hydroxyl radicals detected in hydraulically connected areas and at the surface. The full-scale process employed six injection points and three treatment cycles over a three-month period. Subsequent to treatment, contaminant levels were either nondetectable or were reduced to below applicable New Jersey groundwater standards, with regulatory closure on the site achieved in less than one year.

A series of soil columns was used to investigate the depth of Fenton-like reactions provided by the surface application of catalyzed hydrogen peroxide. Initial experiments examined the effect of fo...

Osteomyelitis of the jaws was relatively common before the era of antibiotic therapy and preventive and restorative dentistry. Osteomyelitis is an acute or chronic inflammatory process that can involve cortical and trabecular aspects of bone or bone marrow. Cranial bones are infrequently involved, but spreading of inflammation with involvement of surrounding structures represents important risk, such as cerebral abscess, encephalitis, or meningitis. The mandible is more commonly involved than the maxilla. Dentogenic infections cause 38% of mandibular and 25% of maxillary involvement. Involvement of zygoma is very rare. Factors like viral fevers, malnutrition, malaria, anemia,tobacco chewing, immunodeficiency, osteopetrosis, Paget’s disease of bone, and florid cemento-osseous dysplasia (FCOD) result in decreased vascularity of the affected bone, predisposing to the development of osteomyelitis. We present a case of osteomyelitis of left maxilla and zygoma with oroantral fistula in an immunocompetent adult male caused by dentogenic infection. The complete resolution of infection was gained with surgical treatment using nasal endoscope and antibiotic therapy. The aims of this paper are to illustrate diagnostic patterns, to report radiographic findings and surgical treatment using nasal endoscope in a case of osteomyelitis of maxilla and zygoma. The prognosis and cosmetic results are discussed.

Laboratory, pilot, and full-scale experiments were used to evaluate and optimize the ISOTECSM remedial process at a warehousing facility in Union, N. J. Based on modified Fenton’s oxidative chemistry, the ISOTEC SM process uses a proprietary catalytic agent which delays formation of reactive hydroxyl radicals. This allows adequate dispersion of the hydroxyl radicals, which is an oxidizing agent, throughout a contaminant plume. Groundwater at the site was contaminated with high levels of gasoline and waste oil constituents, principallybenzene, toluene, ethylebenzene, xylenes (BTEX) andmethyl-t-butylether (MTBE). Bench scale microcosm studies were used to evaluate the appropriate site-specific stoichiometric relationships between catalyst, stabilizers, and oxidizers; the effect of contaminant type and concentration; and the pH optima. Based on results of the laboratory studies, a pilot-scale study was performed at the site. One injection point for catalyst, stabilizers, and oxidant was installed in the contaminated zone at the site, with one hydraulically connected downgradient well used for monitoring. A single treatment of the reagents in the optimal stoichiometry determined from the laboratory study was injected in situ over a period of three days. A 98.5% reduction in volatile organics was observed in the area treated, with the radial extent of treatment estimated to be approximately 20 feet, based on the presence of hydroxyl radicals detected in hydraulically connected areas and at the surface. The full-scale process employed six injection points and three treatment cycles over a three month period. Subsequent to treatment, contaminant levels were either non-detectable or were reduced to below applicable New site. ISOTEC’s treatment activities were completed over several days within a six month period, with the case closed in under a year from start to finish.