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The high-rate aerobic decomposition of food wastes in a slurry bioreactor has been proved as an effective method for the treatment of food wastes. However, experimental evaluation of bioreactor performance on the decomposition of food wastes was found to be a time-consuming procedure. In this study, the decomposition of carbon was closely correlated with oxygen consumption that could be easily calculated from the time variation of dissolved oxygen. From this observation, a prompt and simple method for indirect estimation of decomposition performance was developed. Using the empirical model, the effects of initial concentration of food wastes and aeration rate were successfully estimated and the decomposition performance of the slurry bioreactor could be indirectly estimated by monitoring the time variation of dissolved oxygen.

Microbial oxidation of ferrous iron may be available alternative method of producing ferric iron, which is a reagent used for removal of H2S from biogas. In this study, a submerged membrane bioreactor (MBR) system was employed to oxidize ferrous iron to ferric iron. In the submerged MBR system, we could keep high concentration of iron-oxidizing bacteria and high oxidation rate of ferrous iron. There was membrane fouling caused by chemical precipitates such as K-jarosite and ferric phosphate. However, a strong acidity (pH 1.75) of solution and low ferrous iron concentration (below 3000 mg/l) significantly reduced the fouling of membrane module during the bioreactor operation. A fouled membrane module could be easily regenerated with a 1 M of sulfuric acid solution. In conclusion, the submerged MBR could be used for high-density culture of iron-oxidizing bacteria and for continuous ferrous iron oxidation. As far as our knowledge concerns, this is the first study on the application of a submerged MBR to high acidic conditions (below pH 2).

Microbial oxidation of ferrous iron may be available alternative method of producing ferric sulphate, which is a reagent used for removal of H 2 S from biogas. For practical use of this process, this study evaluated some of the most efficient bioreactor systems for continuous ferrous iron oxidation by iron-oxidizing bacteria. Performances of various bioreactor systems were compared based on the ferrous iron oxidation efficiency according to the stepwise increase of hydraulic loading rates and ease of operation. A submerged-membrane bioreactor and immobilized bioreactor systems were used to increase the cell concentration. In the immobilized bioreactor system, various support media such as a granular activated carbon, polyurethane foam and honeycomb-type ceramics were tested with respect to the cell immobilizing performance. To improve the stability of biofilm, airlift-type immobilized bioreactor system was also developed. In this study, both the membrane bioreactor system and the immobilized bioreactor system using polyurethane foam achieved very good performance of biological ferrous iron oxidation. However, in consideration of economical and operational aspects, the immobilized bioreactor using polyurethane foam is the most practical and efficient system for indirect H 2 S removal using iron-oxidizing bacteria.

金沢大学理工研究域機械工学系, Wastewater from electroplating plants contains several valuable metallic ions such as iron, nickel, and zinc. In general, neutralization followed by sedimentation has been used for the treatment of electroplating wastewater because of low treatment cost and high stability of treated water quality. However, this method results in the production of large amounts of heavy metal sludge that may cause secondary pollution and additional cost. In addition, the recovery of valuable metallic contents from the wastewater sludge has not been technically feasible. It would be highly desirable economically as well as environmentally if a metal recovery process from the wastewater is developed. In the present work, we developed a biological process for metal recovery from electroplating wastewater. Wastewater from electroplating plants contains iron in the form of ferrous ion together with other metal ions. To add economic value to the chemical sludge, iron should be separated from other metals such as nickel and zinc in the wastewater. The iron could be separated from the mixture of metal ions in wastewater by using biological oxidation of ferrous ion into ferric ion followed by stepwise chemical precipitation with hydroxide ion since ferric ion begins to precipitate around pH 4 while ferrous ion precipitates around pH 7 similarly to the other metal ions (nickel and zinc). To improve the biological oxidation, an immobilized bioreactor using polyurethane foam as support media was developed. The bioreactor system showed a very good performance and worked stably over a long period of time. © 2005 American Chemical Society.

When synthetic wastewater containing Cr(VI) was placed in contact with the dead fungal biomass of Aspergillus niger, the Cr(VI) was completely removed from aqueous solution, whereas Cr(III), which was not initially present, appeared in aqueous solution. Desorption and X-ray photoelectron spectroscopy (XPS) studies showed that most of the Cr bound on the biomass was in trivalent form. These results indicated that the main mechanism of Cr(VI) removal was a redox reaction between Cr(VI) and the dead fungal biomass, which is quite different from previously reported mechanisms. The influences of contact time, pH, Cr(VI) concentration, biomass concentration and temperature on Cr(VI) removal were also evaluated. The Cr(VI) removal rate increased with a decrease in pH and with increases in Cr(VI) concentration, biomass concentration and temperature. Although removal kinetics was dependent on the experimental conditions, Cr(VI) was completely removed in the aqueous solution. In conclusion, a new mechanism of Cr(VI) removal by the dead fungal biomass has been proposed. From a practical viewpoint, this abundant and inexpensive dead fungal biomass has potential application in the conversion of toxic Cr(VI) into less toxic or nontoxic Cr(III).

Biomass of the brown seaweed Ecklonia removed both cationic Cr(III) and anionic Cr(VI). The Cr(III) was removed through an ion-exchange mechanism; the Cr(VI) was removed through a redox reaction with the biomass. Among the various pretreatments for developing an efficient biomass, thermal treatment was used in this study. After thermal treatment, the biomass characteristics were investigated using SEM, BET, FTIR, potentiometric titration, and solution analysis. The Cr(III)/Cr(VI) removal performance of the biomass was also examined. The thermal treatment altered the physical and chemical properties of the biomass. The carboxyl groups present in the biomass were decreased to 76% by thermal treatment, but the intraparticular mass transfer resistance increased. These effects of thermal treatment on the biomass reduced the adsorption rate and efficiency of Cr(III) but made the biomass stronger as a Cr(VI) reductant, resulting in an increase in the Cr(VI) reduction rate and the Cr(VI) reducing capacity of the biomass. Therefore, the thermal treatment has to be selectively adopted according to Cr(III) and Cr(VI) concentrations, since it simultaneously reduces and enhances the Cr(III) and Cr(VI) removals, respectively.

The protonated waste biomass of Corynebacterium glutamicum discharged from an industrial lysine fermentation plant was used for the removal of Reactive Orange 16 (RO16). The maximum sorption capaci...

A new type of biomass, protonated brown seaweed Ecklonia sp., was used for the removal of Cr(VI). When synthetic wastewater containing Cr(VI) was placed in contact with the biomass, the Cr(VI) was completely reduced to Cr(III). The converted Cr(III) appeared in the solution phase or was partly bound to the biomass. The Cr(VI) removal efficiency was always 100% in the pH range of this study (pH 1 to approximately 5). Furthermore, the Cr(VI) reduction was independent of the Cr(III) concentration, the reaction product, suggesting that the reaction was an irreversible process under our conditions. Proton ions were consumed in the ratio of 1.15 +/- 0.02 mol of protons/mol of Cr(VI), and the rate of Cr(VI) reduction increased with decreasing the pH. An optimum pH existed for the removal efficiency of total chromium (Cr(VI) plus Cr(III)), but this increased with contact time, eventually reaching approximately pH 4 when the reaction was complete. The electrons required for the Cr(VI) reduction also caused the oxidation of the organic compounds in the biomass. One gram of the biomass could reduce 4.49 +/- 0.12 mmol of Cr(VI). From a practical viewpoint, the abundant and inexpensive Ecklonia biomass could be used for the conversion of toxic Cr(VI) into less toxic or nontoxic Cr(III).

The effects of a nonionic surfactant (Triton X-100) and a metabolic inducer (salicylate) were investigated in order to enhance the biodegradation rate of phenanthrene in soil slurry systems. The addition of salicylate reduced the time for the complete degradation of phenanthrene up to about 3 times (12.9 mg/L-d) even at highly concentrated soils of 650 mg/kg. The inducer was beneficial not only by increasing metabolic activity of existing cells, but also by increasing cell mass since it was utilized as an additional carbon source. The fraction of fast growing bacteria in total with salicylate addition was much higher compared to that without salicylate. The addition of Triton X-100 ranging from 0 to 10 g/L increased the apparent solubility of phenanthrene in soil slurry, but significantly inhibited the phenanthrene degradation in both slurry and pure liquid systems without any inhibition to cell growth. The phenanthrene degradation was inhibited much more with increasing the surfactant concentration. The inhibition by surfactant addition might be due to the prevention of bacterial adhesion to phenanthrene sorbed to soil and/or decrease of micellar-phase bioavailability

An oxide film etched in a magnetically-enhanced CHF3/CF4 plasma has been modeled using neural networks. The etch process was characterized with a 24−1 factorial experiment. The experimental factors and ranges include 20–80 sccm CHF3 flow rate, 10–40 sccm CF4 flow rate, 300–800 W radio frequency (RF) power, and 50–200 mTorr pressure. Radicals (F, CF1, and CF2) measured with optical emission spectroscopy were related to etch responses. In the experiments conducted, increases in etch rate generally corresponded to decreases in nonuniformity. Etch nonuniformity was strongly dependent on RF power. The relative significance of polymer deposition and ion bombardment was separated and explained. The root-mean-squared prediction errors are 174 A/min and 0.425% for etch rate and etch nonuniformity models, respectively.

Metal biosorption behavior of raw seaweed S. filipendula in ten consecutive sorption-desorption cycles has been investigated in a packed-bed flow-through column during a continuous removal of copper from a 35mg/L aqueous solution at pH 5. The elutant used was a 1% (w/v) CaCl2/HCl-solution at pH 3. The sorption and desorption was carried out for an average of 85 and 15h, respectively, representing more than 41 days of continuous use of the biosorbent. The weight loss of biomass after this time was 21.6%. The Cu-biosorption capacity of the biomass, based on the initial dry weight, remained relatively constant at approximately 38 mg Cu/g. Loss of sorption performance was indicated by a shortening breakthrough time and a broadening mass-transfer zone. The column service time, considered up to 1 mg Cu/L in the effluent, decreased continuously from 25.4 h for the first to 12.7 h for the last cycle. The critical bed length, representing the mass-transfer zone, increased almost linearly from 28 to 34cm. "Life-factors" for S. filipendula were found to be 0.0008h(-1) for the breakthrough time and 0.008cm/h for the critical bed length, using an exponential decay and linear fitting functions, respectively. Regeneration with CaCl2/HCl at pH 3 provided elution efficiencies up to 100%. Maximum concentration factors were determined to be in the range 16-44, a decreasing tendency was observed with an increasing exposure time.

We report a case of congenital lacrimal sac fistula located on the temporal side of the lateral canthus. A systemically healthy 1-year-old girl came to the outpatient clinic with a complaint of tearing on the temporal side of the right lateral canthus since birth. On examination, a small orifice was found in the skin on the temporal side of the lateral canthus. There was no evidence of inflammation or swelling within the opening. Surgeons carried out an operation under general anesthesia. They passed a probe through the lacrimal orifice and advanced it toward the lacrimal sac. Next, they introduced saline to the inferior punctum and found that it drained to the lateral fistula. The lower lid stretched as the dissected fistula was pulled. After the operation, the patient was free of the symptom. This paper is to report a case of congenital lacrimal sac fistula located on the temporal side of the lateral canthus.

Factors affecting the astaxanthin production by a unicellular green alga, Haematococcus pluvialis UTEX 16, were evaluated with sequential fractional factorial design. To simulate an actual production mode, a two-stage process was adapted for astaxanthin production: the alga was first cultivated under vegetative growth conditions, and then astaxanthin production was induced by applying various induction methods. A high dose of irradiation was most effective for the production of astaxanthin both in weight (mg/g) and in cellular (pg/cell) contents. A combination of nitrogen deficiency and acetate addition also significantly increased the astaxanthin content of cells on a dry weight basis. Meanwhile, the acetate addition alone increased only the cellular content of astaxanthin. Although the addition of ferrous ion alone had a negative effect on the weight content of astaxanthin, simultaneous addition of ferrous ion and acetate was effective for increasing the cellular content of astaxanthin.

A novel list-based threshold-accepting (LBTA) algorithm is proposed for solving the zero-wait (ZW) scheduling problem. The LBTA algorithm belongs to the class of threshold-accepting algorithms, but the acceptance probability decreases based on a list that is rejuvenated and adapted according to the topology of the solution space of the problem. A probabilistic steepest optimization strategy was adapted to search the solution space effectively. The effectiveness of the LBTA method is illustrated through case studies from scheduling literature which were formulated as mixed-integer linear programming and mixed-integer nonlinear programming models. The performance of the LBTA algorithm is also compared with that of the simulated annealing (SA) algorithm for a large number of various problem sizes. The proposed algorithm gives optimal solutions for small- to moderate-size ZW scheduling problems within a very short time and shows much superior computational performance compared to SA for large-size problems.

A new yeast strain capable of degrading free and metallocyanides was isolated from coke-plant wastewater. The isolated strain designated MCN2 was identified as Cryptococcus humicolus by 26S rDNA sequencing and phylogenetic analysis. During growth of the isolate with KCN as a sole nitrogen source, formamide and formic acid were found as transient intermediates by [(13)C]nuclear magnetic resonance analysis and ammonia accumulated as a final product in the culture medium. The strain MCN2 could degrade high concentrations of tetracyanonickelate (II) (K(2)Ni(CN)(4), TCN) up to 65 mM CN within 60 h when a sufficient amount of glucose was supplied as a carbon source. The maximal degradation rate of TCN was 2.5 mM CN h(-1) at the initial concentration of 51 mM CN.

Nisin was incorporated into binder solutions of acrylic polymer and vinyl acetate-ethylene co-polymer, and then coated on to paper. Diffusive migration of incorporated nisin and the antimicrobial activity of the polymer coatings were investigated in order to understand the way of controlling nisin migration and the extent of microbial suppression by the coated paper. Vinyl acetate–ethylene co-polymer exhibited a faster rate and higher degree of migration into aqueous food simulant solutions compared to acrylic polymer, and also exhibited a higher degree of suppression against Micrococcus flavus ATCC 10240 inoculated into the microbial medium. Addition of NaCl, sugar and citric acid to water significantly reduced the rate of diffusion of nisin in the case of acrylic polymer, while only slight change was observed due to the additive for vinyl acetate-ethylene co-polymer. The simulant type slightly affected the equilibrated migration level of nisin. When the nisin-incorporated coatings were in contact with pasteurized milk and orange juice at 10°C, significant suppression of total aerobic bacteria and yeasts was observed without any noticeable difference between the two types of coatings. Copyright © 2002 John Wiley & Sons, Ltd.

This study characterizes an oxide etching process in a magnetically enhanced reactive ion etching (MERIE) reactor with a CHF 3 /CF 4 gas chemistry. We use a statistical 2 4-1 experimental design plus one center point to characterize the relationships between the process factors and etch responses. The factors that we varied in the design include RF power, pressure, and gas composition, and the modeled etch responses were the etch rate, etch selectivity to TiN, and uniformity. The developed models produced 3D response plots. Etching of SiO 2 mainly depends on F density and ion bombardment. SiO 2 etch selectivity to TiN sensitively depends on the F density in the plasma and the effects of ion bombardment. The process conditions for a high etch selectivity are a 03 to 0.5 CF 4 flow ratio and a -600 V to -650 V DC bias voltage according to the process pressure in our experiment. Etching uniformity was improved with an increase in the CF 4 flow ratio in the gas mixture, an increase in the source power, and a higher pressure. Our characterization of via etching in a CHF 3 /CF 4 MERIE using neural networks was successful, economical, and effective. The results provide highly valuable information about etching mechanisms and optimum etching conditions.

Acremonium strictum, capable of degrading 7.4 g thiocyanate l−1, was isolated from wastewater condensate from coke-oven gas. Ammonia and sulfate were the final products from thiocyanate degradation with a stoichiometric ratio of near 1:1. The highest degradation activity was at pH 6. Although the degradation rate started to be inhibited above 4 g thiocyanate l−1, thiocyanate was completely degraded up to 7.4 g l−1 within 85 h in shake-flask cultures. The degradation of thiocyanate was inhibited by phenol above 625 mg l−1, by cyanide above 16 mg l−1, and by nitrite above 100 mg l−1. However, ammonia and nitrate had negligible inhibition on thiocyanate degradation up to 3 g l−1 and 1.5 g l−1, respectively.

The objectives of this study were to investigate the effect of operating temperature on volatile fatty acids (VFAs) production from microalgal biomass, and to clarify the relationships between VFAs accumulation at different temperatures and the corresponding bacterial communities. The VFA yields were 0.10±0.017, 0.12±0.008, and 0.34±0.009 g/g VS at 35, 45, and 55 °C, respectively. The proportion of acetic acid decreased from 85.6% to 65.8% as operating temperature increased, whereas that of propionic acid increased from near 0% to 15.5% and that of iso-valeric acid remained relatively stable (10.2-11.2%). Bacterial communities at different operating temperatures consisted mostly of the phyla Proteobacteria, Bacteroidetes, and Firmicutes, which can degrade organic compounds effectively. Bacillus sp. was more predominant at 55 °C than at mesophilic temperatures, suggesting that this microorganism contributed significantly to the higher hydrolysis rate and VFA yield at this operating temperature.

A combined mesophilic anaerobic–thermophilic aerobic process was used to treat high-strength food wastewater in this study. During the experimental period, most of solid residue from the mesophilic anaerobic reactor (R1) was separated by centrifugation and introduced into the thermophilic aerobic reactor (R2) for further digestion. Then, thermophilic aerobically-digested sludge was reintroduced into R1 to enhance reactor performance. The combined process was operated with two different Runs: Run I with hydraulic retention time (HRT) = 40 d (corresponding OLR = 3.5 kg COD/m 3 d) and Run II with HRT = 20 d (corresponding OLR = 7 kg COD/m 3 ). For a comparison, a single-stage mesophilic anaerobic reactor (R3) was operated concurrently with same OLRs and HRTs as the combined process. During the overall digestion, all reactors showed high stability without pH control. The combined process demonstrated significantly higher organic matter removal efficiencies (over 90%) of TS, VS and COD and methane production than did R3. Quantitative real-time PCR (qPCR) results indicated that higher populations of both bacteria and archaea were maintained in R1 than in R3. Pyrosequencing analysis revealed relatively high abundance of phylum Actinobacteria in both R1 and R2, and a predominance of phyla Synergistetes and Firmicutes in R3 during Run II. Furthermore, R1 and R2 shared genera ( Prevotella , Aminobacterium , Geobacillus and Unclassified Actinobacteria ), which suggests synergy between mesophilic anaerobic digestion and thermophilic aerobic digestion. For archaea, in R1 methanogenic archaea shifted from genus Methanosaeta to Methanosarcina , whereas genera Methanosaeta , Methanobacterium and Methanoculleus were predominant in R3. The results demonstrated dynamics of key microbial populations that were highly consistent with an enhanced reactor performance of the combined process.

Effective HPLC-DAD and HPLC-ESI-MS/MS methods have been developed for the analysis of eight benzo[c]phenanthridine alkaloids (sanguinarine, chelirubine, macarpine, chelerythrine, dihydrosanguinarine, dihydrochelirubine, dihydromacarpine and dihydrochelerythrine), which are important metabolites in Eschscholtzia californica cell culture. By adopting a ternary gradient pump system, the dihydro-form alkaloids hardly separable from each other could be successfully separated, and all the target alkaloids could be simultaneously quantified with the LOD values of 0.01–0.79 μg/mL and the LOQ values of 0.03–3.59 μg/mL. This HPLC-DAD method was further confirmed by HPLC-ESI-MS/MS system in multiple reaction monitoring mode. Each separated HPLC peak was identified as the target alkaloid, showing its relevant ionized molecule and selected fragment ion. By applying the established method, alkaloid production during the E. californica cell culture could be successfully monitored and some valuable information on its metabolism could be deduced.

To investigate clinical features of infectious endophthalmitis over five years in a South Korean population.Medical records of consecutive patients diagnosed with infectious endophthalmitis at eight institutions located in Gyeongsangnam-do and Pusan city between January 1, 2004 and July 31, 2010 were reviewed.A total of 197 patients were diagnosed and treated. An average of 30.0 infectious endophthalmitis per year was developed. The annual incidence rate of postoperative endophthalmitis during 2006~2009 was 0.037%. The ratios of male to female and right to left were 50.2%: 49.8 % and 54.8%: 43.2%, respectively. Eighth decade and spring were the peak age (36.6%) and season (32.0%) to develop the infectious endophthalmitis. The most common past history in systemic disease was hypertension (40.4%), followed by diabetes (23.4%). Cataract operation (60.4%) was the most common cause, among which most of them was uneventful phacoemulsification (95.9%). Corneal laceration (51.6%) and liver abscess (42.9%) were the most common causes of traumatic and endogenous endophthalmitis, respectively. The percentages of patients with initial and final visual acuity less than counting fingers were 62.6% and 35.2%, respectively. Treatment with vitrectomy with or without intravitreal antibiotics injection was administered to 72.6% of patients, while 17.3% received intravitreal antibiotics only.Our study revealed that the development of infectious endophthalmitis was related with seasonal variation and increased during our study period. Pars plana vitrectomy was preferred for the treatment of infectious endophthalmitis in South Korea.

The present study characterizes the effects of resveratrol (Res) on vascular endothelial growth factor (VEGF) secretion in retinal pigment epithelial (RPE) cells. ARPE-19 cells were treated with CoCl2, a hypoxia mimetic agent. CoCl2 treatment increased protein levels of hypoxia inducible factor-1α (HIF-1α) and CXC-chemokine receptor 4 (CXCR4), and secretion of VEGF. To confirm the effects of Res on VEGF secretion, the human umbilical vein endothelial cell tube formation assay was performed with conditioned medium from Res-treated ARPE-19 cells. The well-known antioxidant Res effectively blocked these effects and reduced phosphorylation of nuclear factor (NF)-κB, an upstream activator of CXCR4. Furthermore, Res also suppressed VEGF secretion induced by SDF-1, a ligand of CXCR4. Conditioned medium from Res-treated ARPE-19 cells clearly suppressed tube formation compared with hypoxia-treated conditioned medium. The results demonstrated that Res inhibited the hypoxia mimetic CoCl2-induced expression of VEGF in ARPE-19 cells. Res suppressed CXCR4 expression through decreased phosphorylation of NF-κB, resulting in downregulation of VEGF secretion.

Balancing the amounts of enzymes is one of the important factors to achieve optimum performance of a designed metabolic pathway. However, the random mutagenesis approach is impractical since it requires searching an unnecessarily large number of variants and often results in searching a narrow range of expression levels which are out of optimal level. Here, we developed a predictive combinatorial design method, called UTR Library Designer, which systematically searches a large combinatorial space of expression levels. It accomplishes this by designing synthetic translation initiation region of mRNAs in a predictive way based on a thermodynamic model and genetic algorithm. Using this approach, we successfully enhanced lysine and hydrogen production in Escherichia coli. Our method significantly reduced the number of variants to be explored for covering large combinatorial space and efficiently enhanced pathway efficiency, thereby facilitating future efforts in metabolic engineering and synthetic biology.

We report that the Fano resonance of self-collimated beams can be achieved in a two-dimensional photonic crystal by introducing a Fano resonator that is composed of zigzag line defects. An asymmetric Fano line shape in a transmission spectrum is generated by the interference between radiated light beams from the resonator and self-collimated beams that directly pass through the resonator without resonance. It is shown that the Fano profile increases in sharpness as the number of zigzag line defects increases because the phase values of the radiated light beams change more rapidly when the number of defects increases. The Fano resonance of self-collimated beams could provide an efficient approach to manipulate light propagation and increase the possibility of application of self-collimated beams. (C) 2014 Optical Society of America

SummaryThe effects of pentachlorophenol (PCP) and 2-chlorophenol (2CP) on white rot fungi,Abortiporus biennis, Cerrena unicolor, Gloeophyllum odoratum, andTrametes versicolorwere investigated. With the exception ofC. unicolorandA. biennis, concentrations of PCP higher than 50 ppm inhibited fungal growth completely. However, extreme concentrations of PCP (500 ppm) caused a 61% increase in growth ofC. unicolorcompared to the control culture within 14 days. When initial PCP concentrations were 50 ppmA. biennisandC. unicolorachieved, respectively, 87% and 78% of chlorophenol transformation within 3 days. However, when 2,5-dimethylaniline (0.2mM) was added to theC. unicolorculture, 98% of PCP transformation was achieved after one hour. Under the same conditions,A. biennistransformed 44% of PCP. Both chlorophenols are completely removed, when laccase activity reaches its maximum. In conclusion, among the four fungi investigated,C. unicolorandA. Bienniswere very effective in transforming PCP and 2-CP. This biotransformation was greatly intensified by 2,5-dimethylaniline and accompanied by an increase in laccase activity.

An online monitoring and controlling system was developed for controlling external carbon addition in the biological nitrogen removal (BNR) process of a coke-plant wastewater treatment plant. Two control regimes, on-off control and feed-forward control, were applied and their performances were compared under normal and abnormal nitrate (NO - 3 -N) input conditions. The water quality of the final effluent was stably controlled under normal nitrate input conditions by using the on-off control algorithm that is connected to the effluent nitrate concentration. However, unexpected nitrite accumulation was observed under abnormal nitrate input conditions (i.e., sudden increase of nitrate concentration), resulting from chemical oxygen demand (COD) limitations during denitrification. On the contrary, the feed-forward control algorithm more reliably controlled external carbon addition even under abnormal nitrate input conditions. The input COD/NO - 3 -N was controlled between 3.55 and 3.62 during the operational period when the feed-forward algorithm was applied. Through trial and error, the optimum value of COD/NO - 3 -N for denitrification was determined to be 3.59 in separate experiments.

Carbon metabolism of activated sludge performing enhanced biological phosphorus removal (EBPR) was investigated in a sequencing batch reactor (SBR), where glucose and acetate were supplied as carbon sources. There have been reports that EBPR often failed because of outgrowth of G-bacteria, which are able to use glycogen (or glucose) alone instead of glycogen and polyphosphate as an internal energy storage pool for the anaerobic uptake and storage of acetate. However, in this experiment, complete EBPR was achieved without proliferation of G-bacteria despite the supply of glucose in addition to the acetate. Additional one-cycle SBR operation was carried out to investigate the detailed metabolism of glucose and acetate. Acetate-using, phosphorus-accumulating organisms (PAOs) could use glucose as a source for the anaerobic polyhydroxyalkanoate (PHA) synthesis from acetate. However, glucose and acetate were metabolized separately through independent metabolic pathways by respective microorganisms: acetate-using PAOs, lactate-producing organisms (LPOs), and lactate-using PAOs. Glucose was rapidly converted to lactic acid by LPOs before acetate-using PAOs used the glucose as an energy source for the anaerobic PHA synthesis from acetate and the lactateusing PAOs anaerobically synthesized PHA from lactate at the expense of polyphosphate. The EBPR was accomplished by acetate-using PAOs and lactate-using PAOs independently when glucose acetate were supplied together.

To understand the possibilities and limitations of the treatment of concentrated nitrate in wastewater, a space-saving biofilm process was introduced to investigate how efficiently concentrated nitrate was utilized in a biofilm process. Lab-scale submerged biofilters stuffed with plastic pall-ring media were developed for the treatment of wastewater containing high nitrate concentration. Two identical biofilters were operated at 2 and 4 hr media HRT in parallel and the concentration of nitrate in the influent was increased stepwise from 50 to 3000 mg-N/L. The concentration of NOx in the effluent was measured at various volumetric loading rates that were proportional to influent nitrate concentrations. There was a critical point for volumetric loading rate (9 kg NO3–N/m3/day) distinguishing the biofilter performances. At the volumetric loading rate below this critical point, the effluent NOx concentration was maintained steadily in spite of the drastic change in the loading rates. However, the effluent NOx concentration severely fluctuated for the small change when the loading rate was higher than the critical point. It was found that the reactor performance was closely related with the biomass concentration (g-dw/ring) in the biofilters.

This work develops and utilizes a non-steady-state model for evaluating the interactions between sorption and biodegradation of hydrophobic organic compounds in soil-slurry systems. The model includes sorption/desorption of a target compound, its utilization by microorganisms as a primary substrate existing in the dissolved phase, and/or the sorbed phase in biomass and soil, oxygen transfer, and oxygen utilization as an electron acceptor. Biodegradation tests with phenanthrene were conducted in liquid and soil-slurry systems. The soil-slurry tests were performed with very different mass transfer rates: fast mass transfer in a flask test at 150 rpm, and slow mass transfer in a roller-bottle test at 2 rpm. The results of liquid tests indicate that biodegradation of the soil-soluble organic fraction did not significantly enhance the biodegradation rate. In the slurry tests, phenanthrene was degraded more rapidly than in liquid tests, but at a similar rate in both slurry systems. Modeling analyses with several hypotheses indicate that a model without biodegradation of compound sorbed to the soil was not able to account for the rapid degradation of phenanthrene, particularly in the roller-bottle slurry test. The model with sorbed-phase biodegradation and the same biokinetic parameters, but unique mass transfer coefficients, simulated the experimental data in both slurry tests most successfully. Reduced mass transfer resistance to bacteria attached to the soil is the most likely phenomenon accounting for rapid sorbed-phase biodegradation.

Alzheimer’s disease is the most common type of dementia and is characterized by a progressive decline in cognitive function due to damage or disease in the brain beyond what may be ex-pected from normal aging. The oldest hypothesis for AD su-ggests that the disease occurs due to reduced biosynthesis of the neurotransmitter acetylcholine. In view of this, several clinical studies

Electron microscopic analysis was used to analyse the morphological characteristics of microbial sludge performing enhanced biological phosphorus removal (EBPR) in an anaerobic/aerobic sequencing batch reactor (SBR) fed with glucose as the sole carbon source. The amounts of phosphate release and uptake during the SBR cycle gradually increased with operation time and complete EBPR was achieved after about 90 days. Scanning electron microscopy (SEM) showed that the initial sludge inoculated into the SBR consisted of various microorganisms such as coccus-, rod- and bacillus-shaped bacteria, but after extended operation (more than 650 days) perpendicular cuboidal bacteria of eight coccus-shaped cells dominated the microbial sludge in the SBR reactor. The cell size of the cuboidal bacteria was about 0.7 μm in diameter. In the sludge, coccus- and rod-shaped bacteria also existed but at much lower frequency. Transmission electron microscopy (TEM) also revealed that the cuboidal bacteria dominated the sludge, but they did not contain polyphosphate granules or glycogen inclusions. The rod-shaped bacteria did not contain polyphosphate granules or glycogen inclusions either. Only coccus-shaped bacteria with a diameter of about 1.2 μm contained small black polyphosphate granules and a large white inclusion. Based on previously proposed metabolic pathways and electron microscopic results, it was inferred that the dominating cuboidal bacteria were lactic acid producing organisms (LPO) and the coccus-shaped bacteria were lactate-using phosphorus accumulating organisms (PAO).

A bioreactor incorporating a slurry-phase reaction was developed for high-rate decomposition of food wastes with an ultimate goal of complete decomposition leaving minimal residue of food wastes when compared to conventional food waste treatment producing composts. In this slurry-phase decomposition, suspended solids in the reactor disappeared with a maximum rate of 7.9 g dry weight dm −3 day −1 . The changes in dissolved oxygen concentration and pH were closely related to the decomposition of food wastes. The concentrations of nitrate and phosphate in the liquid phase also gradually decreased and disappeared completely at the end of five days of operation. Approximately 82% of carbonaceous compounds in the initial food wastes were decomposed during this 5-day operation. Long-term operation of slurry-phase bioreactors with daily addition of fresh food wastes was successfully carried out for 46 days.

Metabolism of enhanced biological phosphorus removal (EBPR) in an anaerobic/aerobic sequencing batch reactor (SBR) was investigated when glucose was supplied as a sole carbon source. There have been several reports claiming that the EBPR could not be accomplished with glucose feed as a carbon source due to the dominating growth of so-called ''G-bacteria'' which do not accumulate polyphosphate and take up glucose without ortho-phosphate release under anaerobic condition. However, in our work, high EBPR could be achieved even with the use of glucose as a sole carbon source following completely diAerent mechanisms from previous reports. Glucose disappearance and glycogen accumulation rapidly occurred, which coincided with other reports. But the release of ortho-phosphate and synthesis of poly 3-hydoxy alkanoic acids (PHAs) were related to total organic carbon (TOC) concentration rather than glucose concentration. The fate of glucose in anaerobic/aerobic stages was investigated by supplying all 13 C-labelled glucose at the beginning of anaerobic stage which was traced by 13 C-NMR spectroscopy. Results showed that the EBPR with glucose supply was accomplished at least by two kinds of microbial populations, a lactic acid producing organism (LPO) and a polyphosphate accumulating organism (PAO). During the anaerobic stage, about 0.42-C mmol of PHAs was synthesized from 1 C-mmol of glucose while 0.12 P- mmol of phosphate was released at pH 6.9. The amount of phosphate release was proportional to the pH value. The amount of PHAs synthesized was less than the amount of glucose added since glucose was converted to the other storage compound (inferred as lactic acid polymer) by the LPO in addition to the PHAs by PAO. During the aerobic phase, PHAs and storage compounds in cells were metabolized and phosphate uptake occurred. In this work, a probable metabolic pathway of PHA synthesis and phosphorus removal was proposed in a SBR supplied with glucose as a sole carbon source. # 2000 Elsevier Science Ltd. All rights reserved

In monitoring and controlling wastewater treatment processes, on-line information of nutrient dynamics is very important. However, these variables are determined with a significant time delay. Although the final effluent quality can be analyzed after this delay, it is often too late to make proper adjustments. In this paper, a neural network approach, a software sensor, was proposed to overcome this problem. Software sensor refers to a modeling approach inferring hard-to-measure process variables from other on-line measurable process variables. A bench-scale sequentially-operated batch reactor (SBR) used for advanced wastewater treatment (BOD plus nutrient removal) was employed to develop the neural network model. In order to improve the network performance, the structure of neural network was arranged in such a way of reflecting the change of operational conditions within a cycle. Real-time estimation of PO43−, NO3−, and NH4+ concentrations was successfully carried out with the on-line information of the SBR system only.

A laboratory-scale drum bioreactor system was used to study engineering aspects of soil bioremediation. Polycyclic aromatic hydrocarbons (PAHs) were chosen as contaminants in soil. In the operation of the reactor, different mixing strategies were applied according to the size of soil without separate washing of sand. The effect of the water content of the soil mixture on solid mixing time and phenanthrene degradation rate was of particular interest. At 20% water content, which was below the saturation level, the mixing efficiency of soil and the degradation rate of phenanthrene was lower than those at 30% or 40% water content. Optimal water content was variable according to the soil texture. The drum bioreactor was operated under optimal water content and PAH concentration (fluorene, phenanthrene, anthracene, pyrene) and microbial numbers were measured in each soil phase (sediment and suspension). Over 95% of PAHs with three or four rings (fluorene, phenanthrene, anthracene, pyrene) were degraded at 270 mg kg−1 soil within 20 days. The degradation rate of PAHs in the suspension phase was higher than that in sediment phase. © 1999 Society of Chemical Industry

After etching Al-Cu alloy films using SiCl4/Cl_2/He/CHF3 mixed gas plasma, the corrosion phenomenon at the grain boundary of the etched surface and a passivation layer on the etched surface with an SF6 plasma treatment subsequent to the etching were studied. In Al-Cu alloy system, corrosion occurs rapidly on the etched surface by residual chlorine atoms, and it occurs dominantly at the grain boundaries rather than the crystalline surfaces. To prevent corrosion, the SF6 gas plasma treatment subsequent to etching was carried out. The passivation layer is composed of fluorine-related compounds on the etched Al-Cu surface after the SF6 treatment, and it suppresses effectively corrosion on the surface as the SF6 treatment pressure increases. Corrosion could be suppressed successfully with the SF6 treatment at a total pressure of 300 mTorr. To investigate the reason why corrosion could be suppressed with the SF6 treatment, behaviors of chlorine and fluorine were studied by various analysis techniques. It was also found that the residual chlorine incorporated at the grain boundary of the etched surface accelerated corrosion and could not be removed after the SF6 plasma treatment.

To determine the roles of the murine interleukin-8 receptor homolog (mIL-8Rh, neutrophil chemokine CXC receptor 2) and macrophage inflammatory protein-1alpha (MIP-1alpha, a CC chemokine) in two eye inflammation models: endotoxin-induced uveitis (EIU) and immune complex-induced uveitis (reverse passive Arthus reaction (RPAR) uveitis).For the EIU model, 250 ng E.coli endotoxin was injected into the vitreous of mIL-8Rh-/- mice or heterozygous littermate mIL-8Rh+/- controls and into MIP-1alpha-/- mice or congenic MIP-1alpha+/+ controls. Eyes were harvested after 24 h for histologic characterization of infiltrating cells and IL-6 bioassays. For the RPAR model, mouse antiserum against human serum albumin (HSA) was injected into the vitreous of mIL-8Rh-/-, mIL-8Rh+/-, MIP-1alpha-/-, and MIP-1alpha+/+ mice. Twenty-four hours later, animals were challenged with intravenous HSA. Eyes were harvested after 4 h for analysis.RPAR resulted in the deposition of immune complexes at the ciliary area and iris with the subsequent development of uveitis. Genetic deficiency of mIL-8Rh reduced the median number of infiltrating cells in EIU by 63% (p0.01) but had no effect on RPAR-induced inflammation. In the EIU model, macrophages comprised a much higher percentage (45%) of infiltrating cells in mice lacking mIL-8Rh than in controls (17%). Loss of the MIP-1alpha gene had no apparent effect on RPAR uveitis and a 39% reduction of infiltrating cells in EIU that was not statistically significant. IL-6 activity in aqueous humor was much less in mice with RPAR uveitis than in those with EIU. Neither gene deletion had a significant impact on IL-6 levels in either disease model.Chemokines acting via mIL-8Rh have a significant role in the induction of neutrophil infiltration during EIU but not during RPAR uveitis. MIP-1alpha is not critical for either EIU or RPAR-induced uveitis. The differential dependence on IL-8-like chemokines is in accord with the two forms ofuveitis having different etiologies and, therefore, potentially different optimal therapies.

Purpose To report a case of an acute onset of delayed postoperative endophthalmitis that was caused by Sphingomonas paucimobilis. Methods This case demonstrates an acute onset of delayed postoperative endophthalmitis at 3 months after uneventful cataract extraction and posterior chamber intraocular lens implantation. We performed vitrectomy, intraocular lens and capsular bag removal, and intravitreal antibiotics injection. On the smear stains from the aspirated vitreous humor, gram-negative bacilli were detected and S. paucimobilis was found in culture. Results At three months after vitrectomy, the best corrected visual acuity was 20/300. Fundus examination showed mild pale color of optic disc and macular degeneration. Conclusions Vitrectomy with intravitreal ceftazidime injection had contributed to the favorable result in case of an acute onset of delayed postoperatire endophthalmitis caused by S. paucimobilis.

A bench-scale airlift submerged bio-lm reactor was developed to test the possibility of nitri-cation of the -nal effluent discharged from a wastewater treatment process of a steel-making plant with an aim of reusing it as irrigation water. Despite the Nuctuation of ammonia concentration in the wastewater (55E 90 mg dm~3), the ammonia was completely converted to nitrate in the NH 3 -N hydraulic retention time of 8 h. When decreasing the hydraulic retention time further down to 4 h, the nitri-cation efficiency decreased to 67E9%. However, the nitri-cation efficiency could be signi-cantly enhanced by increasing the airNow rate due to an increase in both of the oxygen transfer rate and liquid circulation rate. At the aeration rate of 4 dm3 min~1 and the hydraulic retention time of 4 h, the nitri-cation efficiency was as high as 92E6% and the nitri-cation rate was 34E 6m g dm~3 bed h~1. 1998 Society of Chemical Industry NH 3 -N ( J. Chem. T echnol. Biotechnol. 73, 162E168 (1998)

Coke plant wastewater containing high concentrations of ammonia and toxic compounds such as phenol and cyanide was treated using a biological nitrogen removal (BNR) system comprising carbon removal, nitrification, and denitrification stages. The objective of this study was to investigate the feasibility of complete ammonia removal from the coke plant wastewater using a sequential BNR process with external carbon addition. Sodium acetate was introduced as an external carbon source to the denitrification stage after oxidation of phenol and other carbonaceous compounds in the carbon-removal stage. The efficiency of denitrification was strongly affected by the loading rate of the external carbon source, and its optimal rate was determined based on the ratio of chemical oxygen demand to nitrate- and nitrite-nitrogen (COD:NO{sub x}-N) of the denitrification stage. The overall removal efficiency of major soluble pollutants in the wastewater was greater than 95% in the BNR system. When a step input of phenol was introduced to check the stability of the overall system, the nitrification was markedly inhibited because of the incomplete degradation of phenol in the carbon-removal stage. However, after this brief inhibition, the nitrification stage recovered to its normal efficiency within 18 days.

After etching Al–Cu alloy films on Si using a SiCl4/Cl2/He/CHF3 plasma, a corrosion phenomenon on the metal surface was studied. In the Al–Cu alloy system, corrosion occurs rapidly on the etched surface by residual chlorine atoms. To prevent the corrosion, an SF6 plasma treatment subsequent to etching has been carried out. A passivation layer is formed by fluorine-related compounds on the etched Al–Cu surface after the SF6 treatment, and the layer effectively suppresses the corrosion on the surface as the SF6 treatment pressure increases. The corrosion could be successfully suppressed with the SF6 treatment at a total pressure of 300 mTorr.

Corrosion effects following the etching of Al(Cu 1%) using a SiCl 4 /Cl 2 /He/CHF 3 gas plasma have been evaluated. The phenomenon has been studied using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Auger electron spectroscopy (AES). It was found with SEM that the surface of Al(Cu 1%) was mainly corroded at the grain boundary. Using AES point analysis, the cause of selective corrosion at the grain boundary of Al(Cu 1%) has been investigated. The fluorine (F) and chlorine (Cl) on the etched Al(Cu 1%) have been analyzed with AES. The results showed that the contents of F and Cl on the post-SF 6 treated Al(Cu 1%) were different at each of the analyzed positions such as the grain boundaries and crystalline regions. This seems to result from the imperfect crystalline structure of Al(Cu 1%) grain boundaries. The effects of subsequent in situ SF 6 . plasma treatment on the etched Al(Cu 1%) has been also examined using XPS. It was also confirmed that F has passivated the Cl compounds. The AES and XPS results imply that Cl incorporated at the grain boundaries of the polycrystalline Al(Cu 1%) film accelerated the corrosion and could not be easily removed by subsequent SF 6 plasma treatment.

Crab shell particles (Protunus trituberculatus) and activated carbon (Norit 0,8 SUPRA) were used as packing materials in a fixed-bed column. When 1 g crab shell was added in a column packed with 10 g activated carbon, breakthrough occurred at 1500 bed volumes as compared to 380 bed volumes for 10 g activated carbon only. The addition of crab shell particles into an activated carbon column resulted in an increased uptake of lead. The dramatic improvement might be attributed to an increase in and OH− available for binding lead. From the results of SEM, XRD, and FT-IR analyses, the major mechanism of lead removal was based on dissolution of CaCO3 in the crab shell followed by precipitation of Pb3(CO3)2(OH)2(s) on the surface of activated carbon. The lead uptake increased twofold when the influent lead concentration was increased from 10 to 50 mg/L.