Electrothermal adsorption and desorption of volatile organic compounds on activated carbon fiber cloth.

Adsorption is an effective means to selectively remove volatile organic compounds (VOCs) from industrial gas streams and is particularly of use for gas streams that exhibit highly variable daily concentrations of VOCs. Adsorption of such gas streams by activated carbon fiber cloths (ACFCs) and subsequent controlled desorption can provide gas streams of well-defined concentration that can then be more efficiently treated by biofiltration than streams exhibiting large variability in concentration. In this study, we passed VOC-containing gas through an ACFC vessel for adsorption and then desorption in a concentration-controlled manner via electrothermal heating. Set-point concentrations (40-900 ppm(v)) and superficial gas velocity (6.3-9.9 m/s) were controlled by a data acquisition and control system. The results of the average VOC desorption, desorption factor and VOC in-and-out ratio were calculated and compared for various gas set-point concentrations and superficial gas velocities. Our results reveal that desorption is strongly dependent on the set-point concentration and that the VOC desorption rate can be successfully equalized and controlled via an electrothermal adsorption system.

Adsorption and destruction of PCDD/Fs using surface-functionalized activated carbons.

Activated carbon adsorbs polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) from gas streams but can simultaneously generate PCDD/Fs via de novo synthesis, increasing an already serious disposal problem for the spent sorbent. To increase activated carbon's PCDD/F sorption capacity and lifetime while reducing the impact of hazardous waste, it is beneficial to develop carbon-based sorbents that simultaneously destroy PCDD/Fs while adsorbing the toxic chemicals from gas streams. In this work, hydrogen-treated and surface-functionalized (i.e., oxygen, bromine, nitrogen, and sulfur) activated carbons are tested in a bench-scale reactor as adsorbents for PCDD/Fs. All tested carbons adsorb PCDD/F efficiently, with international toxic equivalent removal efficiencies exceeding 99% and mass removal efficiencies exceeding 98% for all but one tested material. Hydrogen-treated materials caused negligible destruction and possible generation of PCDD/Fs, with total mass balances between 100% and 107%. All tested surface-functionalized carbons, regardless of functionality, destroyed PCDD/Fs, with total mass balances between 73% and 96%. Free radicals on the carbon surface provided by different functional groups may contribute to PCDD/F destruction, as has been hypothesized in the literature. Surface-functionalized materials preferentially destroyed higher-order (more chlorine) congeners, supporting a dechlorination mechanism as opposed to oxidation. Carbons impregnated with sulfur are particularly effective at destroying PCDD/Fs, with destruction efficiency improving with increasing sulfur content to as high as 27%. This is relevant because sulfur-treated carbons are used for mercury adsorption, increasing the possibility of multi-pollutant control.

The accuracy of diagnosing neuropsychiatric systemic lupus erythematosus in a series of 49 hospitalized patients.

OBJECTIVE: Neuropsychiatric manifestations in patients with systemic lupus erythematosus (SLE) originate from immune-mediated disease (primary neuropsychiatric SLE) or from other pathogenetic mechanisms indirectly related to SLE (secondary neuropsychiatric SLE). The objective of this study is to describe the clinical practice of diagnosing NP-SLE and to assess how often the diagnosis of primary NP-SLE is changed to secondary NP-SLE and vice versa during the follow-up period in a large series of hospitalized SLE patients. MATERIALS AND METHODS: Data was collected by means of retrospective evaluation of the charts of 191 SLE patients admitted during the period 1986 to 1995. RESULTS: Of 191 admitted SLE patients, 49 had developed neuropsychiatric signs and symptoms. At admission 30 patients were classified as having primary NP-SLE and 19 patients secondary NP-SLE. During follow-up the diagnosis was changed to primary NP-SLE in 2 patients initially diagnosed as suffering from secondary NP-SLE, and in two patients from primary to secondary NP-SLE. Seizures, cognitive deterioration, psychosis and organic brain syndrome were the most frequent manifestations in primary NP-SLE, whereas in secondary NP-SLE headache, seizures, paresis and organic brain syndrome prevailed. 47% of the primary NP-SLE patients were re-admitted to hospital because of recurrent neuropsychiatric manifestations within 4.5 years, while 10% died due to primary NP-SLE. The prognosis of secondary NP-SLE was dependent on the diagnosis. CONCLUSION: In the large majority of patients the initial diagnosis of primary or secondary NP-SLE made upon their admittance to hospital is confirmed during the long-term follow-up.

Aerosol particle and organic vapor concentrations at industrial work sites in Malaysia.

The objective of this study was to establish baseline data about air pollutants potentially related to nasopharyngeal carcinoma (NPC) in the Federal Territory and Selangor, Malaysia. During 1991-1993, ambient air quality was monitored at 42 work sites representing ten industrial sectors: adhesive manufacturing, foundries, latex processing, metalworking, plywood/veneer milling, ricemilling, rubber tire manufacturing, sawmilling, shoemaking, and textile related industries. At each work site, aerosol particle size distributions and concentrations of formaldehyde, benzene, toluene, isopropyl alcohol, and furfural were measured. Mean aerosol particle concentrations ranged from 61 micrograms/m3 in foundries to 5,578 micrograms/m3 in ricemills, with five industries (adhesives, metalworking, ricemilling, sawmilling, and shoemaking) exceeding the US EPA 24-hr ambient air standard for PM-10. Formaldehyde concentrations exceeded the threshold limit value (TLV) in adhesives factories. Other vapours and elements measured were well below TLVs.

Modeling effective diffusivity of volatile organic compounds in activated carbon fiber.

Volatile organic compounds (VOCs) comprise 67% of total hazardous air pollutants (HAPs) that are emitted by major industrial point sources into the U.S. atmosphere (1). Adsorption by activated carbon fiber (ACF) has been recognized as one of the feasible regenerative control processes to separate and recover VOCs for reuse. Characteristics of VOCs transport in ACFs are required to efficiently design ACF sorption systems. However, extensive resources are spent experimentally obtaining transient sorption data to design adsorption systems. As an alternative, this work develops a new model that predicts effective diffusivities of VOCs into ACFs. The diffusion process is modeled as Knudsen transport into the ACF open pore spaces coupled with activated surface diffusion on the ACF's internal surface area. Temperature and Darken's factors are included in the surface diffusion model to provide corrections for thermodynamic state and deviation from Fick's Law, respectively. Depth of the adsorption potential well is considered as the product of the heat of adsorption of a reference VOC, an adsorption similarity factor, and a surface diffusion energy factor. Introduction of the adsorption similarity factor in the effective diffusivity model is a new concept providing a means to predict effective diffusivity of similar adsorption systems from a reference system. Experimental data from a short length column are used to determine effective diffusivity of acetone in ACF. Results from this diffusivity model are compared to experimental values for the acetone/ACF system to describe the degree of closure between modeled and experimental results.

Effects of sulfur impregnation temperature on the properties and mercury adsorption capacities of activated carbon fibers (ACFs).

Laboratory studies were conducted to determine the role of sulfur functional groups and micropore surface area of carbon-based adsorbents on the adsorption of Hg0 from simulated coal combustion flue gases. In this study, raw activated carbon fibers that are microporous (ACF-20) were impregnated with elemental sulfur between 250 and 650 degrees C. The resulting samples were saturated with respect to sulfur content. Total sulfur content of the sulfur impregnated ACF samples decreased with increasing impregnation temperatures from 250 and 500 degrees C and then remained constant to 650 degrees C. Results from sulfur K-edge X-ray absorption near-edge structure (S-XANES) spectroscopy showed that sulfur impregnated on the ACF samples was in both elemental and organic forms. As sulfur impregnation temperature increased, however, the relative amounts of elemental sulfur decreased with a concomitant increase in the amount of organic sulfur. Thermal analyses and mass spectrometry revealed that sulfur functional groups formed at higher impregnation temperatures were more thermally stable. In general, sulfur impregnation decreased surface area and increased equilibrium Hg0 adsorption capacity when compared to the raw ACF sample. The ACF sample treated with sulfur at 400 degrees C had a surface area of only 94 m2/g compared to the raw ACF sample's surface area of 1971 m2/g, but at least 86% of this sample's surface area existed as micropores and it had the largest equilibrium Hg0 adsorption capacities (2211-11,343 micrograms/g). Such a result indicates that 400 degrees C is potentially an optimal sulfur impregnation temperature for this ACF. Sulfur impregnated on the ACF that was treated at 400 degrees C was in both elemental and organic forms. Thermal analyses and CS2 extraction tests suggested that elemental sulfur was the main form of sulfur affecting the Hg0 adsorption capacity. These findings indicate that both the presence of elemental sulfur on the adsorbent and a microporous structure are important properties for improving the performance of carbon-based adsorbents for the removal of Hg0 from coal combustion flue gases.

Evidence of central nervous system damage in patients with neuropsychiatric systemic lupus erythematosus, demonstrated by magnetization transfer imaging.

OBJECTIVE: The clinical symptoms of neuropsychiatric systemic lupus erythematosus (NPSLE) are usually reversible, but whether the associated brain damage is also reversible is still a matter of debate. Since magnetization transfer imaging (MTI) is more sensitive than conventional magnetic resonance imaging (MRI) in demonstrating brain damage, it has become a useful tool in the detection and quantification of diffuse brain disorders such as multiple sclerosis. In this study, MTI was applied to investigate whether central nervous system (CNS) damage is present in patients with a history of NPSLE. METHODS: Eleven female patients with a history of NPSLE and no previous or concurrent primary neurologic or psychiatric disease (ages 17-49 years), 11 female patients with SLE without a history of NPSLE (non-NPSLE; ages 15-51 years), and 10 healthy female controls (ages 17-47 years) underwent MTI. From these MTI scans, quantitative data on the uniformity of the brain parenchyma and atrophy were derived. RESULTS: One NPSLE and 1 non-NPSLE patient were excluded from this study due to infarctions detected with conventional MRI. MTI measures normalized for intracranial volume, reflecting abnormalities of the brain parenchyma as well as atrophy, were lower (P < 0.001) in the NPSLE group than in both control groups. A higher (P < 0.005) mean ratio of cerebrospinal fluid to intracranial volume, indicative of atrophy, was present in the NPSLE group compared with either the non-NPSLE patients or healthy controls. Still, the MTI measures solely reflecting uniformity of the brain parenchyma (normalized for brain volume) were also significantly (P < 0.001) lower in the NPSLE patients than in both control groups. CONCLUSION: This study demonstrates that using MTI, CNS damage can be demonstrated in patients with a history of NPSLE. MTI might, therefore, be an alternative and sensitive tool to detect brain injury in NPSLE, and might also be useful in studying the natural history of the disease.

Female sex hormones at the onset of systemic lupus erythematosus affect survival.

Female sex hormones affect susceptibility to systemic lupus erythematosus (SLE). To determine the effect of female sex hormones at onset of SLE on the survival of these patients, a retrospective survey was performed. The charts of 168 female SLE patients were evaluated to study the disease course, in particular the presence and kind of SLE criteria. Patients were classified as either belonging to the 'high female sex hormone at onset (HH)' or 'low female sex hormone at onset (LH)' group according to age at diagnosis. The statistics of the Dutch population, matched for age, were used to control for differences in life expectancy in these groups. A Cox regression model revealed that the relative mortality risk of HH patients vs HH controls was 4.2 times higher than the relative mortality risk of LH patients compared to LH controls. No differences in the frequency of SLE criteria between HH and LH patients were found that could explain the observed difference in mortality risk.

Association of global brain damage and clinical functioning in neuropsychiatric systemic lupus erythematosus.

OBJECTIVE: To investigate the relationship between quantitative estimates of global brain damage based on magnetization transfer imaging (MTI) and cerebral functioning, as measured by neurologic, psychiatric, and cognitive assessments, as well as disease duration in patients with a history of neuropsychiatric systemic lupus erythematosus (NPSLE). METHODS: In a clinically heterogeneous group of 24 female patients (age range 19-65 years, mean age 35 years) with a history of NPSLE, the correlation values of several volumetric MTI measures and an estimate of cerebral atrophy, neurologic functioning (Kurtzke's Expanded Disability Status Scale [EDSS]), psychiatric functioning (the Hospital Anxiety and Depression Scale [HADS]), and cognitive functioning (cognitive impairment score [CIS] derived from the revised Wechsler Adult Intelligence Scale), as well as several measures of disease duration were assessed using Pearson's correlation coefficient. RESULTS: Quantitative volumetric estimates of global brain damage based on MTI and a measure of global brain atrophy correlated significantly with the EDSS, HADS, and CIS scores. No significant correlation was found between the quantitative estimates of global brain damage and the measures of disease duration. CONCLUSION: The results of this study demonstrate that volumetric MTI parameters and cerebral atrophy reflect functionally relevant brain damage in patients with NPSLE. Furthermore, the absence of a linear relationship between disease duration and results of volumetric MTI measures and atrophy suggests a complicated pattern of accumulating brain damage in patients with NPSLE.

Detection of cerebral involvement in patients with active neuropsychiatric systemic lupus erythematosus by the use of volumetric magnetization transfer imaging.

OBJECTIVE: To determine whether volumetric magnetization transfer imaging (MTI) histogram analysis can detect abnormalities in patients with active neuropsychiatric systemic lupus erythematosus (NPSLE) and to compare the MTI findings in patients with active NPSLE, chronic NPSLE, and multiple sclerosis (MS), as well as in normal control subjects. METHODS: Eight female and 1 male patient with active nonthromboembolic NPSLE (mean +/- SD age 39 +/- 9 years), 10 female patients with chronic NPSLE (age 33 +/- 11 years), 10 female patients with SLE and no history of NPSLE (non-NPSLE; age 34 +/- 11 years), 10 female patients with inactive MS (age 41 +/- 6 years), and 10 healthy control subjects (age 33 +/- 11 years) underwent MTL. Using the MTI scans, histograms were composed from which we derived a variety of parameters that quantitatively reflect the uniformity of the brain parenchyma as well as the ratio of cerebrospinal fluid to intracranial volume, which reflects atrophy. RESULTS: The magnetization transfer ratio (MTR) histograms in the non-NPSLE group and the healthy control group were similar, whereas those in the chronic NPSLE and MS groups were flatter. There was also flattening of the histograms in the active NPSLE group, but with a shift toward higher MTRs. CONCLUSION: Our results indicate that volumetric MTI analysis detects cerebral changes in the active phase of NPSLE. The abnormalities in the brain parenchyma of patients with chronic NPSLE produced MTI values that were the same as those in patients with inactive MS. MTI values in the active phase of NPSLE differed from those in the chronic phase, which might reflect the presence of inflammation. These preliminary results suggest that MTI might provide evidence for the presence of active NPSLE. MTI might also prove to be a valuable technique for monitoring treatment trials.

Childhood-onset Systemic Lupus Erythematosus: clinical presentation and prognosis in 31 patients.

OBJECTIVE: To determine the clinical features at onset, the disease course, and prognostic factors in children with SLE. METHODS: The medical records of 31 patients with childhood-onset SLE were reviewed. Signs and symptoms at onset and during the course of the disease were documented as well as survival and SLICC/ACR damage index. The disease course was compared to 135 consecutive adult-onset SLE patients. RESULTS: Childhood-onset SLE most frequently presented with fatigue, arthritis, fever, weight loss, and malar rash. During follow-up, the frequency of the presence of malar rash, anemia, leukocytopenia, and anti-dsDNA antibodies was significantly higher in childhood-onset than in adult-onset patients. Mean SLICC/ACR damage index was 2.6 after 4.7 years of follow-up. The presence of arthritis, anemia, and seizures at the onset of disease resulted in a 2.6 to 3.9 times higher chance of a severe disease course. CONCLUSION: Patients with childhood-onset SLE suffer from substantial morbidity. Arthritis, anemia, and seizures at onset may be indicators of poor prognosis.

Neuropsychiatric systemic lupus erythematosus is associated with imbalance in interleukin 10 promoter haplotypes.

OBJECTIVE: To investigate the association of interleukin 10 (IL10) promoter polymorphisms and neuropsychiatric manifestations of systemic lupus erythematosus (SLE). METHODS: IL10 haplotypes of 11 healthy volunteers were cloned to confirm that in the Dutch population, only the three common haplotypes (-1082/-819/-592) GCC, ACC and ATA exist. The IL10 promoter polymorphisms of 92 SLE patients and 162 healthy controls were determined. The medical records of the SLE patients were screened for the presence of neuropsychiatric involvement. RESULTS: All cloned haplotypes were either GCC, ACC or ATA. Forty two SLE patients had suffered from neuropsychiatric manifestations (NP-SLE). In NP-SLE patients, the frequency of the ATA haplotype is 30% versus 18% in the controls and 17% in the non-NP-SLE group (odds ratios 1.9, p = 0.02, and 2.1, p = 0.04, respectively), whereas the GCC haplotype frequency is lower in the NP-SLE group compared with controls and non-NP-SLE patients (40% versus 55% and 61%, odds ratios 0.6, p = 0.02 and 0.4 p = 0.006). The odds ratio for the presence of NP-SLE is inversely proportional to the number of GCC haplotypes per genotype when the NP-SLE group is compared with non-NP-SLE patients. CONCLUSIONS: The IL10 locus is associated with neuropsychiatric manifestations in SLE. This suggests that IL10 is implicated in the immunopathogenesis of neuropsychiatric manifestations in SLE.

TNF-308A and HLA-DR3 alleles contribute independently to susceptibility to systemic lupus erythematosus.

OBJECTIVE: To evaluate the respective contributions of tumor necrosis factor (TNF) promoter polymorphisms and HLA-DR alleles to susceptibility to systemic lupus erythematosus (SLE). METHODS: TNF-238G/A and 308G/A promoter polymorphisms and HLA-DRB1 alleles were determined in 99 consecutive Caucasian SLE patients and 177 Caucasian controls. Standard and Mantel-Haenszel odds ratios were calculated to assess the magnitude of the susceptibility factors. The presence or absence of the SLE classification criteria was determined and correlated with the TNF promoter and HLA-DRB1 genotypes. RESULTS: The frequency of the TNF-308A/A and 308G/A genotypes was significantly higher in SLE patients (odds ratio 5.0). Conversely, TNF-238G/A and 238A/A genotypes were equally prevalent in SLE patients and controls. The HLA-DR3 specificity (DRBI*0301 allele) was significantly more prevalent in the SLE population (odds ratio 4.4). Stratification to correct for interdependence of the 2 loci confirmed the association of both TNF-308A and HLA-DR3 with SLE (Mantel-Haenszel odds ratio 3.2 and 2.4, respectively). No correlation was found between TNF promoter and HLA-DRB1 genotypes and any SLE classification criterion or disease manifestation. CONCLUSION: TNF-308A and HLA-DR3 alleles are independent susceptibility factors for SLE.

Effect of folic or folinic acid supplementation on the toxicity and efficacy of methotrexate in rheumatoid arthritis: a forty-eight week, multicenter, randomized, double-blind, placebo-controlled study.

OBJECTIVE: To study the effect of folates on discontinuation of methotrexate (MTX) as single-drug antirheumatic treatment due to toxicity, to determine which type of adverse events are reduced, to study the effects on the efficacy of MTX, and to compare folic with folinic acid supplementation in a 48-week, randomized, double-blind, placebo-controlled trial. METHODS: Patients with active RA (n = 434) were randomly assigned to receive MTX plus either placebo, folic acid (1 mg/day), or folinic acid (2.5 mg/week). The initial MTX dosage was 7.5 mg/week; dosage increases were allowed up to a maximum of 25 mg/week for insufficient responses. Folate dosages were doubled once the dosage of MTX reached 15 mg/week. The primary end point was MTX withdrawal because of adverse events. Secondary end points were the MTX dosage and parameters of efficacy and toxicity of MTX. RESULTS: Toxicity-related discontinuation of MTX occurred in 38% of the placebo group, 17% of the folic acid group, and 12% of the folinic acid group. These between-group differences were explained by a decreased incidence of elevated liver enzyme levels in the folate supplementation groups. No between-group differences were found in the frequency of other adverse events or in the duration of adverse events. Parameters of disease activity improved equally in all groups. Mean dosages of MTX at the end of the study were lower in the placebo group (14.5 mg/week) than in the folic and folinic acid groups (18.0 and 16.4 mg/week, respectively). CONCLUSION: Both folate supplementation regimens reduced the incidence of elevated liver enzyme levels during MTX therapy, and as a consequence, MTX was discontinued less frequently in these patients. Folates seem to have no effect on the incidence, severity, and duration of other adverse events, including gastrointestinal and mucosal side effects. Slightly higher dosages of MTX were prescribed to obtain similar improvement in disease activity in the folate supplementation groups.