bluuebunny/crossref_metadata_2025_split huggingface dataset:
Second neoplasms in pediatric patients with primary central nervous system tumors
Authors: Broniscer Alberto , Ke Weiming , Fuller Christine E. , Wu Jianrong , Gajjar Amar , Kun Larry E. 
Published: April 2004

AbstractBACKGROUNDDetails on second neoplasms (SNs) following pediatric central nervous system (CNS) tumors are scant, because of the rarity of such SNs. The goal of the current study was to investigate and characterize these rare SNs.METHODSThe authors reviewed clinical and treatment data on all institutional patients age < 22 years at diagnosis of a primary CNS tumor who developed any type of SN. Patients with neurofibromatosis type 1 were excluded. Cumulative incidence rates were estimated, and putative risk factors were analyzed.RESULTSThe SNs investigated in the current study included 10 gliomas (42%), 5 meningiomas (21%), 2 desmoid tumors, 2 myelodysplastic syndromes, 2 basal cell carcinomas, 1 leukemia, 1 malignant fibrous histiocytoma, and 1 thyroid carcinoma. Twenty‐one patients had previously received radiotherapy, and 12 patients had received chemotherapy. The SN was related to a genetic cause in 7 patients (29%). Eleven patients died of their SNs, including 8 patients with glioma and 2 patients with myelodysplastic syndromes. The estimated 15‐year cumulative incidence rate for malignant SNs was 4%. Children with choroid plexus tumors had an estimated 10‐year cumulative incidence rate of 20.2%; 2 of those patients had germline TP53 mutations. Age ≤ 2 years was a significant risk factor (P = 0.016) for development of an SN only when patients with genetic conditions were included in the analysis. No significant difference in the estimated cumulative incidence of SNs was found among patients who had received different types of therapy.CONCLUSIONSThe risk of lethal SNs after pediatric CNS tumors is small. Young patients and patients with choroid plexus tumors appear to have an increased risk of SNs that is associated with genetic factors. Cancer 2004. © 2004 American Cancer Society.
Multicomponent Ionic Complexes of Cobalt(II) Tetraphenylporphyrin with C60 Fullerides − Transition from the σ‐Bonded [(CoIITPP)·(C60−)] Anion to Nonbonded CoIITPP and C60·− Components
Authors: Konarev Dmitri V. , Neretin Ivan S. , Saito Gunzi , Slovokhotov Yury L. , Otsuka Akihiro , Lyubovskaya Rimma N. 
Published: April 2004

AbstractNew multicomponent ionic complexes containing [(Cation+)·(C60−)] fullerides and neutral CoIITPP molecules were obtained [the cations are Cs+ (1), tetramethylammonium (CH3)4N+ (2) and N‐methylpyridinium N‐MePy+ (3)]. The crystal structure of 1 determined from single‐crystal X‐ray diffraction analysis contains chains of alternating CoIITPP and C60·− units with voids accommodating solvated [(Cs+)·(C6H5CN)1.64]·CH3CN counter cations. Relatively long Co···C distances between CoIITPP and C60·− in 1 (2.55−3.05 Å) indicate the absence of noticeable bonding of CoIITPP and C60·−. This is consistent with the EPR spectrum of 1, which manifests two EPR signals with g = 2.0009 and 2.4982 attributable to C60·− and CoIITPP, respectively. In contrast to 1, complexes 2 and 3 contain EPR‐silent, σ‐bonded [(CoIITPP)·(C60−)] anions. The influence of the size of counter cations on the stability of σ‐bonded [(CoIITPP)·(C60−)] anions in ionic [(Cation+)·(CoIITPP)·(C60−)] complexes is analyzed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
[CuI(im)]∞: Is this Air‐Stable Copper(I) Imidazolate (8210)‐Net Polymer the Species Responsible for the Corrosion‐Inhibiting Properties of Imidazole with Copper Metal?
Authors: Tian Yun‐Qi , Xu Hai‐Jun , Weng Lin‐Hong , Chen Zhen‐Xia , Zhao Dong‐Yuan , You Xiao‐Zeng 
Published: April 2004

AbstractAn air‐stable two‐dimensional (2D) copper(I) imidazolate polymer, [CuI(im)]∞ (1), with a d10‐d10 interaction, was synthesized solvothermally and structurally characterized by X‐ray crystallography: a = 8.069(2), b = 8.068(2), c = 13.425(3) Å, β = 99.414(3)°, monoclinic, C2/c. This is the first example of an air‐stable copper(I) imidazolate polymer that may play a significant role in the corrosion‐inhibition mechanism of imidazole (or its derivatives) with copper metal. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Scale‐up of catalytic wet oxidation under moderate conditions
Authors: Harf Julien , Hug Andreas , Vogel Frédéaric , Von Rohr Philipp Rudolf 
Published: April 2004

AbstractThe Catalytic Wet Oxidation with pure oxygen is a suitable treatment process for the degradation of organic matter in ivastewaters and sludges. The applied moderate reaction conditions lead only to a partial oxidation of the organics. Therefore the resulting process water has to be purified in a biological treatment plant. In this study, experimental data collected during the wet oxidation of phenol and sewage sludge in a laboratory batch reactor as well as in a pilot plant are presented. A generalized kinetic model combined with a residence time analysis allows to predict accurately the degradation of organic matter in the pilot plant. The wet oxidation of wastewaters and sewage sludge was realized in one single plant concept. Treating suspended or diluted organic wastes produces a highly biodegradable process water containing low molecular oxidation products. Tlje investigated Catalytic Wet Oxidation of sewage sludge generates a residual solid complying with the European quality standards of disposal concerning leachability and organic content. Due to its low capital and operating costs, the Catalytic Wet Oxidation process constitutes an acceptable alternative to incineration for the disposal of sludges.
Pervaporation of pharmaceutical waste streams and synthetic mixtures using water selective membranes
Authors: Shah D. , Bhattacharyya D. , Ghorpade A. , Mangum W. 
Published: April 2004

AbstractThe separation characteristics of binary mixtures and complex pharmaceutical wastes were studied using commercial water selective pervaporation membranes. Various synthetic alcohol‐water (plus salt in some cases) systems and actual waste were utilized for this investigation. The total flux (at 60°C)for the ethanol‐water system decreased from 1.26 to 0.05 ty/m2/hrasthe feed ethanol concentration increased from 35 to 97 wt %. The separation factor (water/ethanol) was found to increase by about 100 times for the same range of concentration. The water/isopmpanol selectivity was found to be considerably higher than the water/ethanol selectivity. The total flux (at 60°C)for the isopropanol‐water system varied from 0.85 to 0.48 kg/m2/hras the feed isopropanol concentration was increased from 35 to 70 wt %. The effect of the presence of salt in the feed on the pervaporation separation was also studied. There was a noticeable effect only at high concentrations of salt in the alcohol‐water feed. Both the total flux and the membrane selectivity were observed to decrease at high salt concentrations. Pervaporation can be used for the volume reduction of pharmaceutical wastes. Pervaporation experiments were performed on a complex pharmaceutical “waste A” at two different temperatures. The total flux (0.9 kg/m2/hr) at 60°C for the waste was observed to be six times the total flux at 28°C whereas the TOC (total organic carbon) reduction factor (7.9) at 60°C was found to 2.5 times that at 28°C. A 87 % removal of the TOC and COD of the waste stream was observed. Pervaporation, using water selective membrane, was also performed on a dilute “Waste B” and only 40 % TOC/COD removal was obtained. Based on the experimental results and operating cost calculations, it can be concluded that pervaporation is indeed an attractive strategy for the volume reduction and for simultaneous reduction of organic concentration in the permeate stream.
Treatability studies of groundwater contaminated with bis(2‐cloroethyl) ether
Authors: Huang Frank Y. C. , Li K. Y. , Liu C. C. 
Published: April 2004

AbstractThe groundwater aquifer underneath a chemical manufacturing plant in Southeast Texas has been contaminated with the leachate from its landfill. There are 17 major chlorinated hydrocarbon contaminants found in the groundwater with concentrations ranging from 1 ppm to 1200 ppm. An air‐stripping unit followed by a thermal catalytic oxidation unit is currently operating on‐site to remove all of the chlorinated compounds from the contaminated groundwater. One of the contaminants, bis(2‐chloroethyl)ether (DCEE), has a fairly low Henry's Law constant; therefore, a high airflow rate is employed in the stripping unit to improve the overall stripping efficiency. Nevertheless, the treated groundwater still contains a fair amount of DCEE.An UV‐peroxidation reactor is set up to study its feasibility for oxidizing DCEE. The treatability data indicate that DCEE at a concentration of 200 ppm can be oxidized effectively in the presence of H2O2. and the effective UV wavelengths lie between 200 and 280 nm. No noticeable reduction of the oxidation rate is observed at low temperature (∼11°C). Apparent oxidation rate equations of DCEE are determined and several process design parameters are discussed.
A mathematical model of an isothermal, flue gas desulforization, copper oxide moving‐bed reactor
Authors: Enick Robert , Gale Tom , Klara Julianne , Jones James 
Published: April 2004

AbstractAn analytical model of an isothermal flue gas desulfurization moving‐bed reactor has been developed. The governing equations can be applied to any moving bed reactor system with pseudo‐first order gas phase kinetics. The average concentrations of SO2 in the effluent gas and CuO in the exiting sorbent are provided by explicit equations. The performance of the moving bed reactor can be predicted with these two simple expressions, thereby eliminating the need for numerical simulators that model the reactor as an array of interconnected microreactors. This analytical model is in agreement with an analytical model developed by Science Applications International Corporation (SAIC). Eight sets of experimental results from DOE's pilot‐scale Life‐Cycle‐Test‐System desulfurization reactor were compared with predictions from both models. No adjustable parameters were used to optimize the fit of the data. The isothermal model underestimated the effluent concentration of SO2 by an average value of 13‐2%, and underestimated the change in composition by 0.066%.
Nitrification of high strength ammonium wastewater in an aerated submerged fixed bed
Authors: Charmot‐Charbonnel Marie‐Louise , Herment Sandrine , Roche Nicolas , Prost Christian 
Published: April 2004

AbstractThe submerged fixed bed offers several advantages for the nitrification process because of its high stability, its compactness, the high applicable volumetric loadings and the very good distribution of the wastewater on the whole biofilm in the reactor. The objectives of this study were to evaluate the performances of this process and the optimal C:N (organic carbon : ammonium‐nitrogen) ratio for the treatment of high strength ammonium wastewaters (0.2 to 5 kg NH4+‐N.m−3). The experiments had been performed with a laboratory‐scale aerated submerged fixed bed, fed by a synthetic substrate (loading rates (Bv) = 0.1 to 2.6 kg NH4+‐N. m−3.d−1). It was found that the best ammonium reduction (72 %) is obtained for a C:N ratio of 1.7 (inlet concentration = 4 kg NH4+‐N.m−3, Bv = 1.9 kg NH4+‐N.m−3.d−1). The COD (Chemical Oxygen Demand) reduction was very good whatever the applied volumetric loading. The nitrification process was stopped when ammonium‐N concentration exceeded 5 kg.m−3 (Bv = 2.6 kg NH4+‐N. m−3.d−1).
Elimination of alkanes from off‐gases using biotrickling filters containing two liquid phases
Authors: Van Groenestijn Johan W. , Lake Mike E. 
Published: April 2004

AbstractBiological techniques are highly cost‐effective for the treatment of off‐gases containing low concentrations of pollutants (< 5 g/m3). They may also be attractive for the elimination of higher concentrations of explosive hydrocarbons (when compared to incineration). Conventional techniques such as biofilters have low elimination capacities for hydrophobic compounds caused by a poor mass transfer from the gas to the aqueous phase.To overcome solubility problems, a novel biotrickling filter was developed and is characterized by the use of an organic solvent. In such a biotrickling filter, a mixture of an organic solvent and water is continuously trickled over a packed bed, while the polluted gas passes counter‐current to the liquid. The microorganisms exist on the packing material and in the circulating liquid. The alkanes are absorbed in the oil phase of the liquid, transfer red to the microorganisms and biodegraded.Laboratory‐scale experiments at 201 scale with hexane as a model pollutant and silicon oil as a solvent revealed that a 90% elimination efficiency can be reached at a volumetric loading rate of 100g hexane per m3 filterbed per hour. The influent gas contained 10 g hexane per m3 and had a temperature of 29°C.The method described in this paper can be a cost‐effective way to treat gases containing hexane, other alkanes or other strongly hydrophobic compounds. Biological co‐oxidation of other biodegradable pollutants from the gas is to be expected.
Evaluation of a two‐stage biofilter for treatment of POTW waste air
Authors: Chitwood Derek E. , Devinny Joseph S. , Edward Reynolds F. 
Published: April 2004

AbstractRecent efforts have been made to reduce releases of air toxics and smog precursors from wastewater treatment plants. Hydrgen sulfide is commonly the primary odor and is an important target for removal. Its oxidation, however, generates sulfuric acid and sometimes elemental sulfur, which can create substantial operational problems for biofilters. Declining pH may inhibit the organisms that degrade compounds other than hydrogen sulfide and may hasten aging of organic Biofilter media. A two‐stage biofilter has been designed and installed at the Ojai Valley Sanitary District wastewater treatment plant. The first stage is an enclosed system with a medium of small, inert, porous stones. It is called an acid gas biofilter. The second stage is a section of a traditional open biofilter filled with wood chips. The acid gas biofilter effectively removed H2S and volatile organic compounds while causing much lower headloss than traditional biofilters. However, considerable flow heterogeneity in both the acid gas biofilter and the wood chip biofilter was observed. The two‐stage system presumably will have a longer bed life because the first stage bed is inert and because the second stage is protected from acidification by removal of H2S in the first stage.
A supported polymeric liquid membrane process for removal of carboxylic acids from a waste stream
Authors: Ho Sa V. 
Published: April 2004

AbstractThe re m oval or elimination of organic residues from aqueous waste streams represents a major need in the chemical industry. We have developed a new class of membrane called “supported polymeric liquid membranes” that are capable of removing and concentrating low molecular weight organic compounds from dilute aqueous solutions, especially those that also contain high concentrations of inorganic salts. Attractive features of this membrane process include the ability to recover the contaminants in concentrated form for either recycle or more economical disposal, low pressure (ambient) operation, simple scale‐up using commercial hollow fiber modules, and ease of in‐situ regeneration of the polymeric liquid. The process has shown treatment feasibility for several types of aqueous waste streams. This paper describes the laboratory development activities for treating a waste stream containing a dilute mixture of C2–C6 carboxylic acids and nitric acid.
AIChE offers technological insights to the public policy debate on global climate change
Authors: Gushee David E. 
Published: April 2004

AbstractGlobal climate change has been a major issue on the national political agenda since 1988. Several Committees on Capitol Hill conducted hearings concerning the heat waves then searing the nation. Testimony by several well‐regarded scientists at those hearings that “we ain't seen nothing yet” led to impressive headlines in the national media. Since then, unusually high temperatures, a succession of forecasts of serious negative impacts from the projected continued warming, and well‐publicized Congressional hearings led to the creation of the United Nation's Framework Convention on Climate Change (FCCC) and its Kyoto Protocol. As a result, climate change is on just about every technology organization's agenda.In 1996, the American Institute of Chemical Engineers joined the list of organizations formally responding to the issue. The Government Relations Committee (GRC) formed a Task Force on Climate Change, made up of Institute members active in a number of aspects of the issue area. The charge to the Task Force: Look for opportunities for the Institute to contribute to the public policy debate on the issue and frame position papers accordingly.The first major conclusion of the Task Force was that AIChE is not in a position to state whether or not global climate change is a real public policy problem. However, to the extent that the public policy process treats climate change as an issue, the Institute is well positioned to comment on the technical merits of proposed policy responses. The Task Force recommended this posture to the GRC, which agreed.
Enhanced scrubbing of chlorinated compounds from air streams
Authors: Johnson Jodi , Parker Wayne , Kennedy Kevin 
Published: April 2004

AbstractThis paper addresses an investigation of mass transfer issues associated with an innovative hybrid process to treat air streams containing chlorinated organics. Three target compounds [dichloromethane (DCM), carbon tetrachloride (CT) and tetra chloroethylene (PCE)] we re evaluated to assess a range of chemical and physical properties.Vegetable oil was found to be an effective scrubbing solution in removing the target compounds from the air streams and was employed in continuous flow tests of a bench‐scale countercurrent packed co lumn. Removal efficiencies approached 90% for all three target compounds with gas‐liquid flow ratios less than 200.A gas‐liquid mass transfer model was developed and compared to the existing Onda correlations, to characterize mass transfer under various operating conditions when water and vegetable oil were employed as scrubbing solutions. It was found that the Onda correlations did not fit the experimental data of vegetable oil very well. The existing Onda correlations we re modified by assuming that the gas phase resistance was controlling mass transfer.In order to enhance mass transfer from the oil phase to an aqueous phase a liquid‐liquid contacting reactor was proposed. The results of the liquid‐liquid reactor suggested that mass transfer could be achieved for compounds that were not highly hydrophobic.
Recovery of sulfur from sour acid gas: A review of the technology
Authors: Eow John S. 
Published: April 2004

AbstractThe modified Claus process is the major technology for the recovery of elemental sulfur from H2S and SO2. A number of commercial technologies for the recovery of sulfur from acid gases are also highlighted here. A Claus tail‐gas clean‐up treatment is essential to give high sulfur recovery efficiency from sour acid gases. Generally, the existing tail‐gas clean‐up technologies can be classified into two groups: those that attain 99% overall sulfur recovery efficiency, and those that achieve 99.9% efficiency, including the sulfur recovered in the Claus unit. These processes are the Amoco's Cold Bed Adsorption (CBA), the SNPA/Lurgi Sulfreen, the IFP, the SCOT, the Beavon, and the Wellman‐Lord processes. The SCOT process is generally the most reliable and flexible technology. Process comparisons are also summarized in terms of the sulfur recovery efficiency, hazards and disadvantages, reliability and advantages, plant capacity and ecological impacts. Several changes and new trends are also highlighted here, such as the introduction of non‐permselective catalytic membrane reactors for the Claus reaction, and the in situ adsorption of water inside the Claus catalytic reactor. The successful utilization of H2S by converting it to sulfur and H2 attains the triple objectives of waste minimization, resource utilization, and environmental pollution reduction. Photochemical and plasmochemical methods are still in the development stage. Application of electrochemical technology to H2S requires further development. Research for an optimum porous catalyst structure is ongoing for obtaining a relation of micropores and macropores which would provide effective conversion of H2S and SO2.
Investigation of a novel jet deflector to avoid slag accumulation around secondary air jets in incinerators and boilers
Authors: Reynolds G. K. , Goh Yoke R. , Sharifi V. Nasserzadeh , Swithenbank Jim 
Published: April 2004

AbstractA major problem in the operation of incinerators is the build‐up of slag on the walls in the throat region of the plant between the furnace chamber and the radiation shaft. This slag can accumulate to a thickness of about one meter, with a weight of several tonnes. This accumulation reduces the availability of the plant, and poses a safety problem, since injury can occur when the material is removed by pneumatic drills during maintenance operations. The excessive downtime, labor, and other economic costs of the slag removal can be minimized by developing a novel, no‐moving‐part jet deflector that can prevent or minimize the accumulation of slag around the jets. The jet deflector was developed and designed by understanding the fundamental principles of the fluid and particle dynamics around the high‐speed jet.Two small‐scale laboratory rigs were constructed for this study. The first rig was a wind tunnel specially designed to minimize the turbulent intensity at the main flow inlet. The second was a combustion rig fitted with an ash/burner injection system, a mobile phone networked particle monitor, and a removable refractory panel onto which the jet and deflector were fitted. An extensive series of laboratory experiments were carried out on both rigs. In parallel with the laboratory investigation, computational fluid dynamic (CFD) analysis of the flow field around the jet and deflector under the same experimental conditions were also conducted. Optimization work on the deflector design was also carried out. Fully optimized jet deflectors were then manufactured and tested in a UK municipal waste incinerator plant. Visual inspections of the jets before and after the deflectors were fitted showed a very significant reduction in the slag formation.