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.

Responses of Portulaca oleracea Linn. to selenium exposure.

The present study was investigated to evaluate the uptake and accumulation of selenium (Se) by the stem cuttings of Portulaca oleracea L. grown in alfisol amended with various concentrations of Se. P. oleracea accumulated a maximum of 63.4 µg g(-1) dry weight in a short growth period of 42 days. The order of accumulation of Se among the plant parts was leaves (31.5 µg g(-1)) > stems (16.4 µg g(-1)) > roots (15.5 µg g(-1)). The accumulation potential was fourfold higher than the plant available concentration of 15.2 µg g(-1) of Se g(-1) of soil (diethylenetriaminepentaacetic acid extracted). Although the plant was able to accumulate Se in their tissues, increase in Se concentrations in soil caused a concentration-dependent decrease in the growth rate of plants (regeneration of leaves, number of leaves, number of roots, root length, stem length and biomass).

Selected enzyme activities of urban heavy metal-polluted soils in the presence and absence of an oligochaete, Lampito mauritii (Kinberg).

Soils samples collected from five different areas (S1-S5) around electroplating industries in the city of Coimbatore were analysed for the activities of selected enzymes (cellulase, phosphatase, amylase, urease, and invertase) in the presence and absence of the earthworm Lampito mauritii (Kinberg). Heavy metal analysis of soils showed that chromium (<504 mg/kg) and copper (<28.1mg/kg) contents were much higher than cadmium (<10.60 mg/kg) except in S5, where cadmium (10.6 mg/kg) was higher than the copper. Except for phosphatase, the activities of all enzymes increased with increasing period of incubation under laboratory conditions, both with and without earthworms. The results of the three-way ANOVA (effect of three factors- worms-with and without addition, soil and incubation time), however, showed that there was no significant difference between enzyme activities (with and without earthworm) and soil and incubation time for amylase and urease activity. Further, no significant difference was found between soils for cellulase activity and between all the above factors for urease activity. The results concluded that though the earthworms died at the end of the incubation period, the resultant increase or decrease in the enzymatic activity may be attributed to the metabolic activities of the worms during their lifetime in the experimental container. Also, the worms after death may have provided suitable substrate for the growth of the microorganisms thereby influencing enzyme activity.

Inverse associations between long-term weight change and serum concentrations of persistent organic pollutants.

There is emerging evidence that persistent organic pollutants (POPs) can increase the risk of various chronic diseases. As POPs mainly bioaccumulate in adipose tissue, weight change can affect serum concentrations of POPs. However, there are few population-based studies on effects of long-term weight change on serum concentrations of POPs. We examined associations between self-reported weight change over 1 year and 10 years and serum concentrations of seven POPs in 1099 adults aged ≥ 40. Serum concentrations of most POPs were higher in those with long-term weight loss, whereas they were lower in those with long-term weight gain. Adjusted correlation coefficients of each POP with weight change for 10 years were -0.23 (P < 0.01) for trans-nonachlor, -0.16 (P < 0.01) for p,p'-dichlorodiphenyldichloroethylene, and -0.21 (P < 0.01) for ß-hexachlorocyclohexane, -0.16 (P < 0.01) for PCB169, -0.20 (P < 0.01) for PCB180 and -0.17 (P < 0.01) for 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin. Weight change for 1 year showed similar but weaker associations, compared with those of long-term weight changes. Although both beneficial health effects after weight loss and harmful health effects after weight gain are generally expected, changes in serum concentrations of POPs in relation to weight change may act on health in directions opposite to what we expect with weight change.

Strong associations between low-dose organochlorine pesticides and type 2 diabetes in Korea.

Low-dose organochlorine (OC) pesticides have recently been associated with type 2 diabetes in several non-Asian general populations. As there is currently epidemic type 2 diabetes in Asia, we investigated the associations between OC pesticides and type 2 diabetes in Koreans. Among subjects who participated in a community-based health survey, we randomly selected 40 diabetic patients and 40 normal controls. Ten OC pesticides (beta-hexachlorocyclohexane, hexachlorobenzene, heptachlor epoxide, p,p'-DDE, p,p'-DDD, p,p'-DDT, o,p'-DDT, oxychlordane, trans-nonachlor, and mirex) detectable in >or=70% of controls were analyzed in relation to diabetes. Most OC pesticides showed strong associations with type 2 diabetes after adjusting for age, sex, BMI, alcohol consumption, and cigarette smoking. Compared with subjects in the lowest tertile of each OC pesticide, adjusted odds ratios (ORs) in the 3rd tertile ranged from 3.1 (95% CI 0.8-12.1) for heptachlor epoxide to 26.0 (95% CI 1.3-517.4) for oxychlordane. In the case of chemicals belonging to the DDT family, adjusted ORs in the 3rd tertile were in the range of 10.6 (95% CI 1.3-84.9) for p,p'-DDT to 12.7 (95% CI 1.9-83.7) for p,p'-DDE. In this exploratory study with small sample, low-dose background exposure to OC pesticides was strongly associated with prevalent type 2 diabetes in Koreans even though absolute concentrations of OC pesticides were no higher than in other populations. Asians may be more susceptible to adverse effects of OC pesticides than other races.

Association between serum concentrations of persistent organic pollutants and prevalence of newly diagnosed hypertension: results from the National Health and Nutrition Examination Survey 1999-2002.

Epidemiological studies have suggested a link between exposure to persistent organic pollutants (POPs) and hypertension. Cross-sectional associations of serum POP concentrations with the prevalence of newly diagnosed hypertension were investigated in 524 adult participants aged >/=40 years in the National Health and Nutrition Examination Survey 1999-2002. Twenty-one POPs (three polychlorinated dibenzo-p-dioxins (PCDDs), three polychlorinated dibenzofurans (PCDFs), five dioxin-like polychlorinated biphenyls (PCBs), six dioxin-unlike PCBs and four organochlorine (OC) pesticides) were selected because they were detectable in > or =60% of participants. Serum concentrations of PCDDs and PCDFs were associated with prevalent but newly diagnosed hypertension among women, but not among men. Across quartiles of the sum of category numbers of the three PCDDs and the three PCDFs, adjusted odds ratios in women were 1.0, 4.2 (95% confidence interval (CI): 1.0-17.1), 4.5 (1.0-19.9) and 5.0 (1.2-21.5) (P for trend=0.08) and 1.0, 2.6 (0.8-9.0), 5.9 (1.7-20.0) and 4.2 (1.3-14.3) (P for trend=0.01), respectively. On the other hand, PCBs tended toward positive association with hypertension only among men. Adjusted odds ratios in men in the highest quartiles of the sum of category numbers of the dioxin-like and non-dioxin-like PCBs were 2.3 (0.8-6.6) and 2.8 (0.9-8.5) (P for trend=0.11 or 0.04), respectively. OC pesticides were not clearly associated with hypertension in either gender. Hypertension had gender-specific associations with serum concentrations of some POPs. Considering the common presence of exposure to POPs in the general population, these findings need to be clarified in prospective studies.

Growth effects of botulinum toxin type A injected into masseter muscle on a developing rat mandible.

OBJECTIVES: Botulinum toxin type A (BTX-A) reduces the muscular contractions by temporarily inhibiting the release of acetylcholine at the neuromuscular junction. The purpose of this study was to investigate the effects of the BTX-A injected into the masseter muscle of a developing rat mandible. MATERIALS AND METHODS: Four-week-old male (no. 80) Sprague-Dawley rats were divided into four groups: control group, saline group, BTX-A group and baseline control group. Rats of baseline group were sacrificed at 0 day to provide baseline values of the mandibular measurements. The masseter muscle of rats in the saline and the BTX-A group were administered with saline and BTX-A solutions respectively. Experimental animals were sacrificed after 4 weeks. RESULTS: The BTX-A group demonstrated smaller mandibular dimension compared with the other groups (P < 0.05). Their condylar cartilages showed increased apoptosis at the proliferation stage of the reserve zone and masseter muscle fibers demonstrated atrophic changes. CONCLUSIONS: The result demonstrated BTX-A influence on inhibitory action of the developing mandible because of apoptosis at the proliferation stage of the reserve zone of the condylar cartilage in developing rat mandible.

Ethylbenzene removal in a multiple-stage biofilter.

In practice, biofilters are often conceived as entire, single-unit systems. However, the activity of a biofilter varies greatly over its depth. For a given period, each stage of the biofilter dominates ethylbenzene removal. Ethylbenzene was continuously removed in a mixed-medium biofilter. The overall removal efficiency of the ethylbenzene ranged from 70% to greater than 99%. In the upflow biofilter, the most dominant ethylbenzene degrading stage shifted consecutively from the bottom to the top of the reactor. Average water content throughout the biofilter media was relatively consistent. However, the water content of each stage fluctuated dramatically and was correlated with the ethylbenzene removal rate. Without any water addition, the biofilter was operated for 62 days above the target removal efficiency of 80%. A 9-month slow-release fertilizer, mixed with composting media, was an effective way to eliminate the nutrient deficiency in the biofilter operation.

Testosterone 5 alpha-reductase inhibitors, menaquinone 7 produced by a Bacillus and phenazine methosulfate.

Menaquinone 7 (MW: 649, C46H64O2), a natural electron acceptor for steroid ring A dehydrogenations, produced by Bacillus sp. SNU-299, was isolated as a rat prostate testosterone 5 alpha-reductase inhibitor with an IC50 value of 4.0 x 10(-5) M from the cultured broth. Phylloquinone was as active as the purified microbial metabolite with an IC50 value of 6.6 x 10(-4) M. On the basis of this evidence, the inhibitory activities of electron carriers, menadione, phenazine methosulfate, and 2,6-dichlorophenolindophenol, for rat prostate testosterone 5 alpha-reductase were tested, and the IC50 values were 3.1 x 10(-6) M, 4.9 x 10(-8) M, 8.9 x 10(-5) M, respectively. A product of the 5 alpha-reductase enzyme reaction and an electron and proton carrier, NADP+, inhibited the 5 alpha-reduction by rat prostate testosterone 5 alpha-reductase with an IC50 value of 9.2 x 10(-5) M. However, the inhibition effect of a proton carrier, carbonylcyanide-m-chlorophenylhydrazone, for rat prostate testosterone 5 alpha-reductase was substantially inactive.