Seasonally related effects on natural organic matter characteristics from source to tap in Korea.

In this study, natural organic matter (NOM) characteristics were investigated over three years of monthly monitoring to determine the effect of seasonal variations on NOM levels from source to tap. Liquid chromatography with organic carbon detection (LC-OCD) was used to determine NOM characteristics and the level of reduction of biodegradable dissolved organic carbon (BDOC). The average dissolved organic matter concentration in the source water (Lake Paldang, Korea) was not significantly different between summer and winter. However, the distribution of NOM components, such as biopolymers, building blocks, low molecular weight (MW) neutrals and acids, identified by LC-OCD, varied seasonally. While high MW NOM was preferentially removed by coagulation/sedimentation/rapid sand filtration (CSR), no seasonal effects were observed on the removal of high MW NOM. CSR and biological activated carbon (BAC) filtration showed a better efficiency of BDOC removal in winter and summer, respectively. High concentrations of chlorine used in the treatment plants in summer resulted in 10% higher DOC concentrations during disinfection. Overall NOM removal efficiencies from source to tap were 45% and 35% for summer and winter, respectively. Principal component analysis also indicated that seasonal variations (principal component 1) showed the strongest positive correlation with the overall performance of water treatment. The long-term monitoring of drinking water treatment processes showed that seasonal variations were important factors affecting NOM characteristics during water treatment.

Clinical characterization and molecular classification of 12 Korean patients with pseudohypoparathyroidism and pseudopseudohypoparathyroidism.

CONTEXT: Pseudohypoparathyroidism (PHP) is defined as resistance toward parathyroid hormones. PHP and pseudopseudohypoparathyroidism (PPHP) are rare disorders resulting from genetic and epigenetic aberrations within or upstream of the GNAS locus. This study investigated the clinical characteristics and performed a molecular analysis of PHP and PPHP. METHODS: A total of 12 patients with (P)PHP from 11 unrelated families (4 with PHP-Ia, 6 with PHP-Ib, and 2 with PPHP) were characterized using both clinical and molecular methods. Clinical features included the presenting symptoms, Albright hereditary osteodystrophy features, and resistance to hormones. Comprehensive analysis of the GNAS and STX16 loci was undertaken to investigate the molecular defects underlying (P)PHP. RESULTS: All PHP-Ib patients displayed hypocalcemic symptoms. All PHP-Ia patients showed resistance toward TSH, in addition to PTH. In most patients with PHP, when the diagnosis of PHP was first established, hypocalcemia and hyperphosphatemia were associated with a significant increase in serum PTH levels. One patient with PHP-Ia was diagnosed with growth hormone deficiency and showed a good response to human recombinant growth hormone therapy. 6 patients with PHP-Ia and PPHP showed 5 different mutations in the GNAS gene. 5 patients with PHP-Ib displayed a loss of differentially methylated region (DMR) imprints of the maternal GNAS. One PHP-Ib patient showed a de novo microdeletion in STX16 and a loss of methylation of exon A/B on the maternal allele. No patients revealed paternal disomy among 4 patients with PHP-Ib. CONCLUSIONS: Identification of the molecular causes of PHP and PPHP explains their distinctive clinical features and enables confirmation of the diagnosis and exact genetic counseling.

IgE-mediated anaphylaxis and allergic reactions to idursulfase in patients with Hunter syndrome.

BACKGROUND: Enzyme replacement therapy (ERT) with recombinant human idursulfase is effective for the treatment of Hunter syndrome, mucopolysaccharidosis (MPS) type II. However, various adverse events can occur by the infusion of idursulfase. The purpose was to evaluate the occurrence of infusion-related allergic reactions, including anaphylaxis, to idursulfase in patients with MPS II receiving ERT and to elucidate its possible mechanism. METHODS: A total of 34 patients with MPS II were enrolled to receive ERT with Elaprase(®) at a dose of 0.5 mg/kg intravenously once a week. Information regarding the symptoms, frequency, and timing of anaphylaxis during treatment was analyzed. Presence of anti-idursulfase IgE antibody was assessed by skin prick test (SPT) and enzyme-linked immunosorbent assay (ELISA). Western blotting was performed to confirm the reaction between idursulfase and specific IgE. RESULTS: Three patients (8.8%) showed anaphylaxis by infusion of idursulfase. No deaths occurred during the study. Anti-idursulfase IgE antibody was detected by SPT and ELISA. Immunoblotting with patients' sera and Elaprase(®) showed a single band of specific IgE binding to the protein around 70 kD, and idursulfase did not display amino acid sequence homology to known allergens. SPT with idursulfase demonstrated positive results in all patients with anaphylaxis. However, we failed to reveal any risk factors for the development of infusion-related immediate-type allergic reactions. CONCLUSIONS: Anaphylaxis related to infusion of idursulfase is mediated by anti-idursulfase IgE antibody, which might be produced by de novo synthesis. SPT is useful in predicting the occurrence of anti-idursulfase IgE-mediated anaphylaxis during infusion.

Interleukin-13/-4-induced oxidative stress contributes to death of hippocampal neurons in aß1-42-treated hippocampus in vivo.

AIMS: The present study examined whether Aß(1-42) can induce endogenous expression of interleukin-13 (IL-13) or (IL-4) within activated microglia in the rat hippocampus in vivo. We further investigated whether these cytokines mediate ROS/RNS generation through activation of NADPH oxidase and/or inducible nitric oxide synthase (iNOS), and thus contribute to the degeneration of hippocampal neurons in vivo. RESULTS: Here, we show that IL-13 and IL-4, endogenously expressed in Aß(1-42)-activated microglia in hippocampus in vivo, contribute to degeneration of hippocampal neurons in vivo. Neutralization of IL-13 and IL-4 protected hippocampal neurons in vivo against neurotoxicity by inhibiting activation of microglial NADPH oxidase and iNOS, resulting in attenuation of ROS generation and oxidative damage of protein, lipid and DNA. INNOVATION: To our knowledge, this is the first study to demonstrate the possible involvement of endogenously expressed IL-13 and/or IL-4 in activated microglia after Aß(1-42) injection in the degeneration of hippocampal neurons in vivo. The current findings suggest that the deleterious effects of microglia-derived endogenous IL-13 and/or IL-4 are involved in oxidative stress-mediated neurodegenerative diseases, such as AD. CONCLUSION: We carefully hypothesize that IL-13 and IL-4, well-known as anti-inflammatory cytokines might serve as neurotoxic mediators by enhancing microglia-derived oxidative stress in Aß(1-42)-treated hippocampus in vivo.

Neural progenitors generated from the mesenchymal stem cells of first-trimester human placenta matured in the hypoxic-ischemic rat brain and mediated restoration of locomotor activity.

Term placenta is a great reservoir of mesenchymal stem cells (MSCs), however, the potential of the earlier placenta is largely unknown. In this report, we established 17 MSC lines from 19 first-trimester human placenta (fPMSC). fPMSC proliferated for 90-150 days in vitro and by enhanced cellular interaction, fPMSC differentiated into nestin-expressing neural progenitor cells (fPMSC-NP), accompanied by inductions of immature neuron-specific genes. Therapeutic effect of the fPMSC-NP was tested in the animal model of hypoxia-ischemia (HI) which was devastating to dopaminergic neurons and to locomotor activity. Improvement of motor activity was evident as early as 2 weeks after transplantation of the fPMSC-NP into bilateral striatum and became indistinguishable from that of the age-matched normal animals by 8 weeks but no spontaneous recovery was observed in the control-grafted animals. Immunohistochemical analyses revealed that the implanted fPMSC-NP matured into ectodermal cells including the tyrosine hydroxylase (TH)-expressing neurons in the recipient striatum. So, the improved motor behavior was likely due to the dopaminergic differentiation of the implanted fPMSC-NP in the dopaminergic-denervated host brain. Based on this result, we propose that progenitors may be more advantageous than the terminally differentiated cells for the purpose of cell replacement therapies since the progenitors are easily obtainable and are expected to be more pliable to the new environment.

Low power consumption and high sensitivity carbon monoxide gas sensor using indium oxide nanowire.

In this paper, micro gas sensor was fabricated using indium oxide nanowire for effective gas detection and monitoring system. Indium oxide nanowire was grown using thermal CVD, and their structural properties were examined by the SEM, XRD and TEM. The electric properties for microdropped indium oxide nanowire device were measured, and gas response characteristics were examined for CO gas. Sensors showed high sensitivity and stability for CO gas. And with below 20 mw power consumption, 5 ppm CO could be detected.

High sensitive NO2 gas sensor with low power consumption using selectively grown ZnO nanorods.

The noble gas sensor using multiple ZnO nanorods was fabricated with CMOS compatible process and sol-gel growth method on selective area and gas response characteristics to NO2 gas of the sensor device were investigated. We confirmed the sensors had high sensitive response denoted by the sensitivity of several tens for NO2 gas sensing and also showed pretty low power consumption close to 20 mW even though the recovery of resistance come up to almost the initial value.

Hydrogenotrophic denitrification in a packed bed reactor: effects of hydrogen-to-water flow rate ratio.

Hydrogen dissolution and hydrogenotrophic denitrification performance were investigated in a lab-scale packed bed reactor (PBR) by varying the hydrogen flow rate and hydraulic retention time (HRT). The denitrification performance was enhanced by increasing the hydrogen flow rate and HRT as a result of high dissolved hydrogen concentration (0.39mg/L) and utilization efficiencies (79%). In this study, the hydrogen-to-water flow rate ratio (Q(g)/Q(w)) was found to be a new operating factor representing the two parameters of hydrogen flow rate and HRT. Hydrogen dissolution and denitrification efficiency were nonlinearly and linearly correlated with the Q(g)/Q(w), respectively. Based on its excellent linear correlation with denitrification efficiency, Q(g)/Q(w) should be greater than 2.3 to meet the WHO's guideline of nitrate nitrogen for drinking water. This study demonstrates that Q(g)/Q(w) is a simple and robust factor to optimize hydrogen-sparged bioreactors for hydrogenotrophic denitrification.

The extracellular signal-regulated kinase pathway contributes to the control of behavioral excitement.

The extracellular signal-regulated kinase (ERK) pathway mediates neuronal plasticity in the CNS. The mood stabilizers lithium and valproate activate the ERK pathway in prefrontal cortex and hippocampus and potentiate ERK pathway-mediated neurite growth, neuronal survival and hippocampal neurogenesis. Here, we examined the role of the ERK pathway in behavioral plasticity related to facets of bipolar disorder. Mice with ERK1 ablation acquired reduced phosphorylation of RSK1, an ERK substrate, in prefrontal cortex and striatum, but not in hippocampus or cerebellum, indicating the ablation-induced brain region-specific ERK signaling deficits. ERK1 ablation produced a behavioral excitement profile similar to that induced by psychostimulants. The profile is characterized by hyperactivity, enhanced goal-directed activity and increased pleasure-related activity with potential harmful consequence. ERK1-ablated mice were hyperactive in multiple tests and resistant to behavioral despair in the forced swim test. These mice displayed more home-cage voluntary wheel running activities, rearings in a large arena and open-arm visits in an elevated plus maze. Treatments with valproate and olanzapine, but not lithium reduced baseline activities in ERK1-ablated mice. All three treatments attenuated amphetamine-induced hyperactivity in ablated mice. These data indicate a profound involvement of ERK1 signaling in behavioral excitement and in the behavioral action of antimanic agents. The extent to which ERK pathway perturbation contributes to the susceptibility, mood switch mechanism(s) and symptom pathophysiology of bipolar disorder requires further investigation. Whether there is a shared mechanism through which mood stabilizers produce their clinical actions on mood, thought and behavioral symptoms of mania also requires further investigation.

Electrical characterization of ZnO single nanowire device for chemical sensor application.

Vertically well-aligned high quality ZnO nanowires were grown on GaN epilayer on c-plane sapphire via a vapor-liquid-solid (VLS) process by introducing an Au thin film (3 nm) as a catalyst. ZnO single nanowire device was ingenuously fabricated by combining conventional optical lithography and high resolution electron beam lithography and its current-voltage characteristics were measured with doing the post process to acquire reproducible performance as a chemical gas sensor. And its temperature dependent current-voltage characteristics were measured to investigate temperature dependant electrical transport. The ZnO nanowire device showed slightly non-ohmic current-voltage characteristics which may be due to back-to-back configuration of the diodes with the insulating contact barriers and showed an relatively small activation energy of 0.2 eV. To test our device as a chemical sensor, the NO2 gas response was reported at the elevated temperature.

Ozone treatment of wastewater sludge for reduction and stabilization.

Ozonation was applied to wastewater sludge for reduction and stabilization. Ozone was found to be very effective at reducing sludge and producing a useful carbon source. An ozone dose of 0.3 g/gDS fulfilled the criteria for the disinfection of class A type biosolids. The sludge treated with 0.5 gO(3)/gDS produced no hydrogen sulfide for a month at 29 degrees C. Ozonation resulted in low pH conditions, which might facilitate the mobilization of heavy metals from sludge. The results of a geotechnical investigation proved that the residuals of ozone-treated sludge did not meet the required properties required for landfill cover without the addition of quick lime.

Fate of effluent organic matter (EfOM) and natural organic matter (NOM) through riverbank filtration.

Understanding the fate of effluent organic matter (EfOM) and natural organic matter (NOM) through riverbank filtration is essential to assess the impact of wastewater effluent on the post treatment requirements of riverbank filtrates. Furthermore, their fate during drinking water treatment can significantly determine the process design. The objective of this study was to characterise bulk organic matter which consists of EfOM and NOM during riverbank filtration using a suite of innovative analytical tools. Wastewater effluent-derived surface water and surface water were used as source waters in experiments with soil columns. Results showed the preferential removal of non-humic substances (i.e. biopolymers) from wastewater effluent-derived surface water. The bulk organic matter characteristics of wastewater effluent-derived surface water and surface water were similar after 5 m soil passage in laboratory column experiment. Humic-like organic matter in surface water and wastewater effluent-derived surface water persisted through the soil passage. More than 50% of total dissolved organic carbon (DOC) removal with significant reduction of dissolved oxygen (DO) was observed in the top 50 cm of the soil columns for both surface water and wastewater effluent-derived surface water. This was due to biodegradation by soil biomass which was determined by adenosine triphosphate (ATP) concentrations and heterotrophic plate counts. High concentrations of ATP in the first few centimeters of infiltration surface reflect the highest microbial activity which correlates with the extent of DOC reduction. Good correlation of DOC removal with DO and biomass development was observed in the soil columns.

Evidence for the involvement of the kainate receptor subunit GluR6 (GRIK2) in mediating behavioral displays related to behavioral symptoms of mania.

The glutamate receptor 6 (GluR6 or GRIK2, one of the kainate receptors) gene resides in a genetic linkage region (6q21) associated with bipolar disorder (BPD), but its function in affective regulation is unknown. Compared with wild-type (WT) and GluR5 knockout (KO) mice, GluR6 KO mice were more active in multiple tests and super responsive to amphetamine. In a battery of specific tests, GluR6 KO mice also exhibited less anxious or more risk-taking type behavior and less despair-type manifestations, and they also had more aggressive displays. Chronic treatment with lithium, a classic antimanic mood stabilizer, reduced hyperactivity, aggressive displays and some risk-taking type behavior in GluR6 KO mice. Hippocampal and prefrontal cortical membrane levels of GluR5 and KA-2 receptors were decreased in GluR6 KO mice, and chronic lithium treatment did not affect these decreases. The membrane levels of other glutamatergic receptors were not significantly altered by GluR6 ablation or chronic lithium treatment. Together, these biochemical and behavioral results suggest a unique role for GluR6 in controlling abnormalities related to the behavioral symptoms of mania, such as hyperactivity or psychomotor agitation, aggressiveness, driven or increased goal-directed pursuits, risk taking and supersensitivity to psychostimulants. Whether GluR6 perturbation is involved in the mood elevation or thought disturbance of mania and the cyclicity of BPD are unknown. The molecular mechanism underlying the behavioral effects of lithium in GluR6 KO mice remains to be elucidated.

Growth of carbon nanotubes on fully processed silicon-on-insulator CMOS substrates.

This paper describes the growth of Carbon Nanotubes (CNTs) both aligned and non-aligned on fully processed CMOS substrates containing high temperature tungsten metallization. While the growth method has been demonstrated in fabricating CNT gas sensitive layers for high temperatures SOI CMOS sensors, it can be employed in a variety of applications which require the use of CNTs or other nanomaterials with CMOS electronics. In our experiments we have grown CNTs both on SOI CMOS substrates and SOI CMOS microhotplates (suspended on membranes formed by post-CMOS deep RIE etching). The fully processed SOI substrates contain CMOS devices and circuits and additionally, some wafers contained high current LDMOSFETs and bipolar structures such as Lateral Insulated Gate Bipolar Transistors. All these devices were used as test structures to investigate the effect of additional post-CMOS processing such as CNT growth, membrane formation, high temperature annealing, etc. Electrical characterisation of the devices with CNTs were performed along with SEM and Raman spectroscopy. The CNTs were grown both at low and high temperatures, the former being compatible with Aluminium metallization while the latter being possible through the use of the high temperature CMOS metallization (Tungsten). In both cases we have found that there is no change in the electrical behaviour of the CMOS devices, circuits or the high current devices. A slight degradation of the thermal performance of the CMOS microhotplates was observed due to the extra heat dissipation path created by the CNT layers, but this is expected as CNTs exhibit a high thermal conductance. In addition we also observed that in the case of high temperature CNT growth a slight degradation in the manufacturing yield was observed. This is especially the case where large area membranes with a diameter in excess of 500 microns are used.

A high filtration system with synthetic permeable media for wastewater reclamation.

A novel filtration process with synthetic permeable media was investigated for secondary effluent reclamation. Polyurethane was chosen as the filter medium among three tested media. Compressibility and up-flow velocity were changed to determine the optimum operation for the system. An equation was introduced to express the relationship between the removal efficiency and up-flow velocity. In a pilot study, the synthetic medium filtration with compression showed very stable effluent quality without clogging trouble, though the system operated with three times higher filtration rate and much longer backwashing interval than conventional systems.

Chromosome aberration and lipid peroxidation in chromium-exposed workers.

Chromosome aberration frequency and lipid peroxidation levels were analyzed to investigate their efficacy as biological markers for monitoring the genotoxicity and oxidative damage in Korean chromium (Cr)-exposed workers. Fifty-one Cr-exposed workers and 31 age-matched controls in ten chrome-plating plants were sampled. The Cr level was measured in the workers' blood and urine, and in the ambient air at the workplaces. The conventional Giemsa staining method and fluorescence in situ hybridization (FISH) technique were used for chromosome aberration analysis. Spectrum green whole chromosome paint specific for chromosome 4 was used in the FISH procedure. As for lipid peroxidation, malondialdehyde (MDA) was measured in the blood plasma as thiobarbituric acid-reactive substances (TBARS). The blood Cr concentration was statistically correlated with both the frequency of chromatid exchange and the total frequency of chromosome/chromatid breaks and exchanges, as detected by the Giemsa staining. Meanwhile, the frequency of translocation, as detected by the FISH technique, was significantly higher in the Cr-exposed workers than in the controls and it correlated with the blood Cr concentration. Although the concentration of MDA, the metabolite of lipid peroxidation, in the exposed workers was higher than that of the controls, no statistically significant correlation between the MDA level and the blood or urine Cr levels was observed. Accordingly, the genotoxicity and oxidative damage (plasma lipid peroxidation) in the Korean Cr-exposed workers were consequential at quite low exposure levels, plus chromosome rearrangement, especially translocation, was clearly evident as a biological response marker for Cr exposure based on a significant positive correlation between the translocations detected by FISH and the Cr in the blood.

Ozonation of wastewater sludge for reduction and recycling.

An ozone treatment system was introduced as an alternative method for municipal sludge treatment and disposal. A pilot-scale facility was built to investigate the feasibility of the ozonation for sludge reduction and recycle. The system consists of three main parts; advanced wastewater treatment, sludge ozone treatment and belt press dewatering. Ozonation of wastewater sludge resulted in mass reduction by mineralization as well as volume reduction by improvement of dewatering characteristics. The supernatant of the ozonated sludge, consisting of solubilized organics and micro-particles, proved to be an effective carbon source for denitrification. A simple economic assessment reveals that the ozonation process can be more economical than incineration for sludge treatment and disposal at small- and medium-sized wastewater treatment plants.

Reduction of sludge by ozone treatment and production of carbon source for denitrification.

The feasibility of ozone treatment of municipal sludge for sludge reduction and carbon source production has been investigated. Significant accumulation of solubilized organics and unsettlable micro-solids (UMS) was observed at relatively low ozone dosages while mineralization became dominant at higher dosages. Batch denitrification experiments showed that the solubilized organics and the UMS could be utilized as carbon sources for nitrogen removal. In terms of overall sludge reduction, 54% reduction of the total sludge mass could be achieved by ozone treatment at 0.2 g-O3/g-MLSS.

Acetate injection into anaerobic settled sludge for biological P-removal in an intermittently aerated reactor.

Injecting acetate into the sludge layer during the settling and decanting periods was adopted to enhance phosphorus release inside the sludge layer during those periods and phosphorus uptake during the subsequent aeration period in a KIST Intermittently Decanted Extended Aeration (KIDEA) process. The relationship among nitrification, denitrification and phosphorus removal was investigated in detail and analyzed with a qualitative floc model. Dependencies of nitrification on the maximum DO level during the aerobic phase and phosphorus release on residual nitrate concentration during the settling phase were significant. High degree of nitrification resulted that phosphorus release inside the sludge layer was significantly interfered with nitrate due to the limitation of available acetate and the carbon sources from influent. Such limitation was related to the primary utilization of organic substance for denitrification in the outer layer of the floc and the retarded mass transfer into the inner layer of the floc. Nevertheless, effects of acetate injection on both denitrification and phosphorus release during the settling phase were significant. Denitrification rate after acetate injection was two times as high as that before acetate injection, and phosphorus release reached about 14 mg PO4(3-)-P/g MLVSS/hr during the decanting phase after the termination of denitrification inside the sludge layer. Extremely low level of maximum DO (around 0.5 mg/L) during the aerobic phase may inhibited nitrification, considerably, and thus nearly no nitrate was present. However, the absence of nitrate increased when the phosphorus release rate was reached up to 33 mg PO4(3-)-P/g MLVSS/hr during the settling and decanting phase, and nearly all phosphorus was taken up during subsequent aerobic phase. Since the sludge layer could function as a blocking layer, phosphorus concentrations in the supernatant was not influenced by the released phosphorus inside the sludge layer during the settling and decanting period. Phosphorus removal was directly (for uptake) and indirectly (for release) dependent on the median and maximum DO concentration during the aerobic phase, and those optimal values may exist within the range from 0.2 to 0.6 mg/L and 0.4 to 1.2 mg/L, respectively.

Lung fibrosis in Sprague-Dawley rats, induced by exposure to manual metal arc-stainless steel welding fumes.

To investigate the disease process of pneumoconiosis induced by welding-fume exposure, a lung fibrosis model was established by building a stainless steel arc welding fume generation system and exposing male Sprague-Dawley rats for 90 days. The rats were exposed to welding fumes with concentrations of 57-67 mg/m3 (low dose) and 105-118 mg/m3 (high dose) total suspended particulates for 2 h per day in an inhalation chamber for 90 days. The concentrations of the main metals, Fe, Mn, Cr, and Ni, were measured in the welding fumes, plus the gaseous compounds, including nitrous gases and ozone, were monitored. During the exposure period, the animals were sacrificed after the initial 2-h exposure and after 15, 30, 60, and 90 days. Histopathological examinations were conducted on the animals' upper respiratory tract, including the nasal pathway and conducting airway, plus the gas exchange region, including the alveolar ducts, alveolar sacs, and alveoli. When compared to the control group, the lung weights did not increase significantly in the low-dose group, yet in the high-dose group there was a significant increase from day 15 to day 90. The histopathological examination combined with fibrosis-specific staining (Masson's trichrome) indicated that the lungs in the low-dose group did not exhibit any progressive fibrotic changes. Whereas, the lungs in the high-dose group exhibited early delicate fibrosis from day 15, which progressed into the perivascular and peribronchiolar regions by day 30. Interstitial fibrosis appeared at day 60 and became prominent by day 90, along with the additional appearance of pleural fibrosis. Accordingly, it would appear that a significant dose of welding-fume exposure was required to induce lung fibrosis.