Recent developments of capillary electrophoresis in seawater analysis.

Recent applications of capillary electrophoresis (CE) to the determination of various seawater analytes are critically examined, with the aim to reveal method's state-of-the-art and possible future research trends in the area. Given highly developed separation and detection methodology, emphasis is given to the most advantageous sample preconcentration strategies used to evolve the method's practical utility, particularly to low-level analytes. Analytical performance of CE applied to seawater analysis is illustrated with a selection of real-world applications published from 2006, from which it appears that the primary developmental tendency is presently confined to a transit from inorganic to organic seawater analytes.

Dementia with Lewy bodies can be well-differentiated from Alzheimer's disease by measurement of brain acetylcholinesterase activity-a [11C]MP4A PET study.

OBJECTIVE: To investigate the diagnostic performance of brain acetylcholinesterase (AChE) activity measurement using N-[(11) C]-methyl-4-piperidyl acetate (MP4A) and PET in patients with dementia with Lewy bodies (DLB) and Alzheimer's disease (AD). METHODS: Participants were 14 DLB patients, 25 AD patients and 18 age-matched healthy controls (HC). All subjects underwent PET scans and MP4A to measure regional brain AChE activity. We performed anatomical standardization of each brain image, and k3 values, an index of AChE activity, in each voxel were estimated by nonlinear least squares analysis. Volumes of interest (VOIs) were identified on parametric k3 images in frontal, temporal, parietal and occipital cortices, and in anterior and posterior cingulate gyri (ACG and PCG). In each VOI, the differential diagnostic performance between AD and DLB of k3 values was assessed by area under the curve (AUC) of the receiver-operating characteristic. Voxel-based statistical analyses were also performed. RESULTS: Mean cortical AChE activities in AD patients (-8.2% compared with normal mean) and DLB patients (-27.8%) were lower than HCs (p < 0.05, p < 0.001, respectively). There was a significant difference in mean cortical AChE activities between AD and DLB patients (p < 0.001). All regional brain AChE activities of defined VOIs except ACG were able to well discriminate DLB from AD, and notably performance was the most significant in PCG (AUC = 0.989, 95% CI: 0.965-1.000). CONCLUSIONS: Brain cholinergic deficit is consistently prominent in DLB compared with AD. PET measurement of brain AChE activity may be useful for the differential diagnosis between DLB and AD.

Enhanced removal of sodium salts supported by in-situ catalyst synthesis in a supercritical water oxidation process.

For practical applications of supercritical water oxidation to wastewater treatment, the deposition of inorganic salts in supercritical phase must be controlled to prevent a reactor from clogging. This study investigated enhanced removal of sodium salts with titanium particles, serving as a salt trapper and a catalyst precursor, and sodium recovery by sub-critical water. When Na(2)CO(3) was tested as a model salt, sodium removal efficiency was higher than theoretically maximum efficiency defined by Na(2)CO(3) solubility. The enhanced sodium removal resulted from in-situ synthesis of sodium titanate, which could catalyse acetic acid oxidation. The kinetics of sodium removal was described well by a diffusion mass-transfer model combined with a power law-type rate model of sodium titanate synthesis. Titanium particles showed positive effect on sodium removal in the case of NaOH, Na(2)SO(4) and Na(3)PO(4). However, they had negligible effect for NaCl and negative effect for Na(2)CrO(4), respectively. More than 99% of trapped sodium was recovered by sub-critical water except for Na(2)CrO(4). In contrast, sodium recovery efficiency remained less than 50% in the case of Na(2)CrO(4). Reused titanium particles showed the same performance for enhanced sodium removal. Enhanced salt removal supported by in-situ catalyst synthesis has great potential to enable both salt removal control and catalytic oxidation.

Mapping of brain acetylcholinesterase alterations in Lewy body disease by PET.

OBJECTIVE: To characterize brain cholinergic deficits in Parkinson disease (PD), PD with dementia (PDD), and dementia with Lewy bodies (DLB). METHODS: Participants included 18 patients with PD, 21 patients with PDD/DLB, and 26 healthy controls. The PD group consisted of nine patients with early PD, each with a disease duration of less than 3 years, five of whom were de novo PD patients, and nine patients with advanced PD, each with a disease duration greater than or equal to 3 years. The PDD/DLB group consisted of 10 patients with PDD and 11 patients with DLB. All subjects underwent PET scans with N-[11C]-methyl-4-piperidyl acetate to measure brain acetylcholinesterase (AChE) activity. Brain AChE activity levels were estimated voxel-by-voxel in a three-compartment analysis using the arterial input function, and compared among our subject groups through both voxel-based analysis using the statistical parametric mapping software SPM5 and volume-of-interest analysis. RESULTS: Among patients with PD, AChE activity was significantly decreased in the cerebral cortex and especially in the medial occipital cortex (% reduction compared with the normal mean = -12%) (false discovery rate-corrected p value <0.01). Patients with PDD/DLB, however, had even lower AChE activity in the cerebral cortex (% reduction = -27%) (p < 0.01). There was no significant difference between early PD and advanced PD groups or between DLB and PDD groups in the amount by which regional AChE activity in the brain was reduced. CONCLUSIONS: Brain cholinergic dysfunction occurs in the cerebral cortex, especially in the medial occipital cortex. It begins in early Parkinson disease, and is more widespread and profound in both Parkinson disease with dementia and dementia with Lewy bodies.

Simultaneous removal of nitrate and pesticides from groundwater using a methane-fed membrane biofilm reactor.

Nitrate and pesticide contaminated ground- and surface-waters have been found around the world as a result of the use of these compounds in agricultural activities. In this study we investigated a biological treatment method to simultaneously remove nitrate and pesticides from contaminated water. Methane was supplied as the sole source of carbon to the microbial culture. A methane-fed membrane biofilm reactor (M-MBfR) was developed in which the methane was supplied through hollow-fiber membranes to a biofilm growing on the membrane surface. A methane-oxidizing culture enriched from activated sludge was used as inoculum for the experiments. Removal of nitrate and the four pesticides atrazine, aldicarb, alachlor, and malathion was examined both in suspended culture and in the M-MBfR. The maximum denitrification rate with suspended culture was 36.8 mg N gVSS(-1) d(-1). With the M-MBfR setup, a hydraulic retention time of approximately one hour was required to completely remove an incoming nitrate concentration of about 20 mg NO3-N l(-1). The microbial culture could remove three of the pesticides (aldicarb, alachlor, and malathion). However, no atrazine removal was observed. The removal rates of both nitrate and pesticides were similar in suspended culture and in membrane-attached biofilm.

Behaviors of physiologically active bacteria in water environment and chlorine disinfection.

Direct microscopic methods using several fluorescent staining were applied to estimate the proportion of physiologically active bacteria in the water environment and evaluate the efficacy of disinfection with chlorine. 4',6-diamidino-2-phenylindole (DAPI) was used to determine total bacterial numbers, and 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) was chosen for direct detection of respiring bacteria. BacLight kit was used to assess bacterial membrane integrity. Bacteria with growth potential were enumerated using the DVC method and microcolony technique. The total bacterial number in river was 8 x 10(6)-3 x 10(10) cells/mL, and colony forming units on R2A medium were 1 x 10(4)-4 x 10(5) cfu/mL. In the case of wastewater treatment plant, 1-10% of total bacterial cells could form colonies. Physiologically active bacteria in river and wastewater treatment plant determined by fluorescent staining were much higher than those obtained by plate counting. The effect of chlorine on the physiological viability of Escherichia coli was also investigated. Microscopic viable bacteria were even more chlorine resistant than culturable bacteria. The inactivation rate coefficients of direct viable bacteria were one-second to third those of culturable bacteria.

A membrane biofilm reactor achieves aerobic methane oxidation coupled to denitrification (AME-D) with high efficiency.

Methane would potentially be an inexpensive, widely available electron donor for denitrification of wastewaters poor in organics. Currently, no methanotrophic microbe is known to denitrify. However, aerobic methane oxidation coupled to denitrification (AME-D) has been observed in several laboratory studies. In the AME-D process, aerobic methanotrophs oxidise methane and release organic metabolites and lysis products, which are used by coexisting denitrifiers as electron donors for denitrification. Due to the presence of oxygen, the denitrification efficiency in terms of methane-to-nitrate consumption is usually low. To improve this efficiency the use of a membrane biofilm reactor was investigated. The denitrification efficiency of an AME-D culture in (1) a suspended growth reactor, and (2) a membrane biofilm reactor was studied. The methane-to-nitrate consumption ratio for the suspended culture was 8.7. For the membrane-attached culture the ratio was 2.2. The results clearly indicated that the membrane-attached biofilm was superior to the suspended culture in terms of denitrification efficiency. This study showed that for practical application of the AME-D process, focus should be placed on development of a biofilm reactor.

Photosynthetic bacteria pond system with infra-red transmitting filter for the treatment and recovery of organic carbon from industrial wastewater.

A photosynthetic bacteria pond system was applied to the treatment of food industrial wastewater and recovery of carbon in the form of purple non-sulphur bacterial (PnSB) cell. The effect of infra-red transmitting filter on the selection of microbial groups in the system was investigated. It was found that more than 90% of organic removal could be achieved when the system was operated at HRT of 3 to 10 days, even though some fluctuations were observed at lower HRT. Infra-red transmitting filter could suppress the growth of microalgae in the system and allow the purple non-sulphur to grow in the system. Nevertheless, they could be outgrown by sulphate-reducing bacteria at higher organic loading rates. The growth of purple sulphur bacteria associated with sulphate reducing bacteria was also observed. ORP is a crucial operating factor to control the system under micro-anaerobic conditions which is preferred to the growth of purple non-sulphur bacteria.

Estimation of biologic gasification potential of arsenic from contaminated natural soil by enumeration of arsenic methylating bacteria.

Volatile arsenic species are found in gases released from natural environments as a result of natural ambient-temperature biomethylation of arsenic conducted by yeast, fungi, and bacteria. This process is part of arsenic transport in the arsenic geocycle. It is important to determine the flux of gasified arsenic released by microorganisms to determine the quantitative flux of arsenic cycle clearly and also to understand the effect of microorganisms on the transport and distribution of arsenic in the contaminated environment. In this study, biologic gasification potential of natural soil was determined by enumeration of arsenic methylating bacteria (AsMB). Enumeration of AsMB was conducted for 10 contaminated sites in Bangladesh where AsMB concentration varies from 0.2 x 10(4) to 7.8 x 10(4) most probable number (MPN) kg(-1) dry soil. The specific gasification rate of arsenic by microorganisms was estimated as 1.8 x 10(-7) microg As MPN(-1) d(-1) by incubation of soil in a laboratory soil column setup. Natural biologic gasification potential of arsenic was then calculated by multiplying the specific rate by the number of AsMB in different soils. The attempt of this study is a fundamental step in determining the volatilization flux of arsenic from land surface contributed by microorganisms.

Evaluation of a long-term operation of a submerged nanofiltration membrane bioreactor (NF MBR) for advanced wastewater treatment.

Nanofiltration (NF) is considered as one of the most promising separation technologies to obtain a very good-quality permeate in water and wastewater treatment. A submerged NF membrane bioreactor (NF MBR) using polyamide membranes was tested for a long-term operation and the performance of the NF MBR was compared with that of a microfiltration MBR (MF MBR). Total organic carbon (TOC) concentration in the permeate of the NF MBR ranged from 0.5 to 2.0 mg/L, whereas that of the MF MBR showed an average of 5 mg/L. This could be explained by the tightness of the NF membrane. Although the concentration of organic matter in the supernatant of the NF MBR was higher than that in the permeate due to high rejection by the NF membrane, the NF MBR showed excellent treatment efficiency and satisfactory operational stability for a long-term operation.

Comparison of treatment efficiency of submerged nanofiltration membrane bioreactors using cellulose triacetate and polyamide membrane.

This study evaluates the performance of nanofiltration membrane bioreactor (NF MBR) systems using cellulose triacetate (CA) and polyamide (PA) membranes. The results indicated that both NF membranes could produce high quality permeate in the submerged NF MBR system. In addition, hollow fiber CA membranes exhibited the capability of higher permeate productivity than PA membranes. However, to obtain high quality permeate for a long-term operation, CA membranes should be maintained using an appropriate method, such as chlorine disinfection, in order to control the membrane biodegradation. The results demonstrated that PA membranes were capable of producing higher quality permeate for a long period than CA membranes. In order to enhance the practicability of PA membranes in submerged NF MBR systems, it is required that the membranes should have the lowest possible intrinsic salt rejection.

The amygdala and Alzheimer's disease: positron emission tomographic study of the cholinergic system.

The primary transmitter deficit is cholinergic in Alzheimer's disease (AD), and the amygdala receives a major cholinergic projection from the nucleus basalis of Meynert (Ch4), which may play an important role in the retention of affective conditioning and/or memory consolidation. We measured brain acetylcholinesterase (AChE) activity in 54 patients with AD and in 22 normal controls by positron emission tomography and N-[(11)C]methylpiperidin-4-yl acetate to characterize the cholinergic pathology in AD. The k(3) values were calculated as an index of AChE activity in a three-compartment model analysis using the metabolite-corrected arterial input function. The k(3) values were highly significantly reduced by 20% in the cerebral neocortex (P <0.0001 in the two-tailed t test), 14% in the hippocampus (P <0.001), and 33% in the amygdala (P <0.0001) in AD patients compared with normal controls. The k(3) values were significantly correlated with the Mini-Mental State Examination scores in both the cerebral cortex (P <0.001) and the amygdala (P <0.05) in AD patients, supporting the cholinergic hypothesis of cognitive dysfuncion in AD. Further studies are required, however, to elucidate the specific role of the cholinergic deficit in the amygdala in the emotional and behavioral symptoms in AD.

Survival of Salmonella spp. in a simulated acid-phase anaerobic digester treating sewage sludge.

The presence of pathogenic microorganisms in municipal waste sludge may create a serious outbreak of water borne diseases if the sludge is used for agricultural purpose. An attempt to decrease the number of pathogenic microorganisms, Salmonella spp. using a simulated acid-phase anaerobic digester was tested in a laboratory-scale batch experiment. Reduction of Salmonella spp. was demonstrated in a mixture of sludge and organic acid, simulating an acid digester of a two-phase anaerobic digestion process. A high concentration of organic acid at a pH value of 5.5-6.0 prevents a decrease in Salmonella spp. concentration. Almost complete destruction of Salmonella spp. is observed within two days if the pH value is maintained below 5.5.

Survival of Salmonella spp. in a simulated acid-phase anaerobic digester treating sewage sludge.

The presence of pathogenic microorganisms in municipal waste sludge may create a serious outbreak of water borne diseases if the sludge is used for agricultural purpose. An attempt to decrease the number of pathogenic microorganisms, Salmonella spp. using a simulated acid-phase anaerobic digester was tested in a laboratory-scale batch experiment. Reduction of Salmonella spp. was demonstrated in a mixture of sludge and organic acid, simulating an acid digester of a two-phase anaerobic digestion process. A high concentration of organic acid at a pH value of 5.5-6.0 prevents a decrease in Salmonella spp. concentration. Almost complete destruction of Salmonella spp. is observed within two days if the pH value is maintained below 5.5.

Isolation and examination of copper removing bacteria from activated sludge culture.

Experiments were carried out to isolate metal removing bacteria from activated sludge culture and test the metal removal capability of isolated bacteria. Two concentrations of copper solution (CuCl2) used to select the copper-tolerance level of each isolate were 0.05 mM and 2.5 mM. Experimental data showed that isolates could be obtained by using non-selective medium (NSM) in the presence of copper. The isolates were displayed on agar plates with diverse colonial morphological characteristics. A maximum uptake of 81 mg/g dry cell mass was observed at an initial copper concentration of 50 mg/l. The minimum uptake was 9 mg/g dry cell mass. Copper uptake efficiency by isolates from NSM with 0.5 mM CuCl2 was significantly different with those from NSM with 2.5 mM CuCl2.

Kinetic analysis of [(11)C]MP4A using a high-radioactivity brain region that represents an integrated input function for measurement of cerebral acetylcholinesterase activity without arterial blood sampling.

N -[(11)C]methylpiperidin-4-yl acetate ([(11)C]MP4A) is an acetylcholine analog. It has been used successfully for the quantitative measurement of acetylcholinesterase (AChE) activity in the human brain with positron emission tomography (PET). [(11)C]MP4A is specifically hydrolyzed by AChE in the brain to a hydrophilic metabolite, which is irreversibly trapped locally in the brain. The authors propose a new method of kinetic analysis of brain AChE activity by PET without arterial blood sampling, that is, reference tissue-based linear least squares (RLS) analysis. In this method, cerebellum or striatum is used as a reference tissue. These regions, because of their high AChE activity, act as a biologic integrator of plasma input function during PET scanning, when regional metabolic rates of [(11)C]MP4A through AChE (k(3); an AChE index) are calculated by using Blomqvist's linear least squares analysis. Computer simulation studies showed that RLS analysis yielded k(3) with almost the same accuracy as the standard nonlinear least squares (NLS) analysis in brain regions with low (such as neocortex and hippocampus) and moderately high (thalamus) k(3) values. The authors then applied these methods to [(11) C]MP4A PET data in 12 healthy subjects and 26 patients with Alzheimer disease (AD) using the cerebellum as the reference region. There was a highly significant linear correlation in regional k(3) estimates between RLS and NLS analyses (456 cerebral regions, [RLS k(3) ] = 0.98 x [NLS k(3) ], r = 0.92, P < 0.001). Significant reductions were observed in k(3) estimates of frontal, temporal, parietal, occipital, and sensorimotor cerebral neocortices (P < 0.001, single-tailed t-test), and hippocampus (P = 0.012) in patients with AD as compared with controls when using RLS analysis. Mean reductions (19.6%) in these 6 regions by RLS were almost the same as those by NLS analysis (20.5%). The sensitivity of RLS analysis for detecting cortical regions with abnormally low k 3 in the 26 patients with AD (138 of 312 regions, 44%) was somewhat less than NLS analysis (52%), but was greater than shape analysis (33%), another method of [(11)C]MP4A kinetic analysis without blood sampling. The authors conclude that RLS analysis is practical and useful for routine analysis of clinical [(11)C]MP4A studies.

High-throughput characterization for organic pollutants in environmental waters using a capillary electrophoresis chip.

To evaluate organic pollution in water, we did preliminarily studies on high-throughput characterization of organic pollution in water using microchip-based capillary electrophoresis (CE) with laseer-induced fluorescence (LIF) detection. The applied voltage was investigated to control the gated valve injection and CE separation for conventional cross type microchips using a self-made personal computer (PC)-based controller as the voltage supply. We obtained high-throughput data for the reproducible separation of fluorescein isothiocyanate (FITC)-labeled river-water samples using a zwitter-ion based buffer solution to avoid adsorption of the labeled sample onto the channel of a microchip made from quartz glass. We used real samples from the Hino River that flows into Lake Biwa, from ten sampling points and obtained several reproducible peaks in different separation patterns for each sample within 2 min. We successfully demonstrated high-throughput characterization of dissolved organic carbon (DOC) in environmental water using the microchip.

Isolation of copper-binding proteins from activated sludge culture.

Six copper-binding microbial proteins were isolated from activated sludge cultures grown on media containing copper at various concentrations. Molecular weights among isolated proteins were ranged from 1.3k to 1 74k dalton. Isolated proteins were compared for their copper binding capabilities. Proteins isolated from cultures grown in the presence of copper in the growth media exhibited higher copper binding capabilities than those isolated from the culture grown in the absence of copper. The highest metal uptake of 61.23 (mol copper/mol protein) was observed by a protein isolated from a culture grown with copper at a concentration of 0.25 mM. This isolated protein (CBP2) had a molecular weight of 24k dalton. Other protein exhibited copper binding capability of 4.8-32.5 (mol copper/mol protein).