[FTIR spectrum and detoxication of extracellular polymeric substances secreted by microorganism].

In order to explore the effect of extracelluar polymeric substances (EPS) on resistance and removal of heavy metals, the production of EPS, secreted by cadmium-resistant strain (SCSE425-7) and cadmium-removal strain (SCSE709-6) was investigated combined with Fourier transform infrared spectroscopy (FTIR). The results showed that the high resistance to cadmium of strain SCSE425-7 was related to the high production of soluble EPS, whereas SCSE709-6 secreted more insoluble EPS resulting in better cadmium removal performance. It was indicated that soluble extracellular carbohydrates may help the bacteria to enhance resistance to Cd2+, and insoluble EPS could contribute to Cd2+ removal effectively. The FTIR spectra showed that the peaks of amide and carboxyl were main functional groups for Cd2+ adsorption.

[FTIR spectrum and coagulation enhancement of exopolysaccharide secreted by an Antarctica bacterium Pseudoalteromona sp. Bsi20310].

Bsi20310 exopolysaccharide (Bsi20310 EPS) was secreted by a bacteria named Pseudoalteromonas sp. Bsi20310, isolated from Antarctic Sea ice. Crude Bsi20310 EPS was prepared by precipitation of the culture solution with ethanol, with proteins removed by using chloroform and butanol preparatorily. The results showed that Bsi20310 EPS improved the FeCl3 coagulation performance on synthetic water-soluble dye reactive red X-3B dyeing wastewater, obviously. The optimum coagulation enhancement of Bsi20310 EPS expressed by decolorization rate is from 16% to 84%, at pH near 10, Fe(III) concentration of 0. 98 mmol x L(-1) and Bsi20310 EPS concentration of 150 mg x L(-1), respectively. Fourier transform infrared spectroscopy (FTIR) was used to investigate the functional groups of Bsi20310 EPS, Fe(III)-Bsi20310 EPS floc and Fe(III)-Bsi20310 EPS-reactive red X-3B floc. The spectra showed that Bsi20310 EPS contained a large number of functional groups such as -OH, -COOH and glycosidic bond. Some certain functional groups of Bsi20310 EPS changed being combined with Fe(III) hydrolysate. For instance, narrow peaks at 3429 and 1650 cm(-1) became wide; the peak at 2 921 cm(-1) weakened or disappeared; the peak at 1242 cm(-1) red-shifted slightly; peaks in the region of 1151-1038 cm(-1) became single and sharp, etc. The change in spectra indicated that -OH, -OOH and glycosidic bond might be the main functional groups. The study suggested a bright prospect of Bsi20310 EPS performing as an approach to safe and effective microbial coagulation enhancement.

On-line optical determination of floc size of Fe(III) coagulants.

This study investigated the floc aggregation, average floc size, floc size variance and floc growth velocity when ferric chloride (FeCl3) and polyferric chloride (PFC) were used to treat the simulated water samples. The factors including coagulant dose, ionic strength and solution pH, which affect the floc aggregation, were studied. Experiments were carried out in a bench-scale reactor using photometric dispersion analyzer (PDA). Results showed that there were great differences between the floc aggregation of PFC and FeCl3. The average floc size and floc growth velocity of PFC were much larger than those of FeCl3. Compared with FeCl3, PFC gave a better coagulation performance in wider range of pH, dosage and ionic strength. It was also found that the coagulation efficiency of PFC did not depend on average floc size but on floc growth velocity.

A physiology-based seizure detection system for multichannel EEG.

BACKGROUND: Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. Electroencephalogram (EEG) signals play a critical role in the diagnosis of epilepsy. Multichannel EEGs contain more information than do single-channel EEGs. Automatic detection algorithms for spikes or seizures have traditionally been implemented on single-channel EEG, and algorithms for multichannel EEG are unavailable. METHODOLOGY: This study proposes a physiology-based detection system for epileptic seizures that uses multichannel EEG signals. The proposed technique was tested on two EEG data sets acquired from 18 patients. Both unipolar and bipolar EEG signals were analyzed. We employed sample entropy (SampEn), statistical values, and concepts used in clinical neurophysiology (e.g., phase reversals and potential fields of a bipolar EEG) to extract the features. We further tested the performance of a genetic algorithm cascaded with a support vector machine and post-classification spike matching. PRINCIPAL FINDINGS: We obtained 86.69% spike detection and 99.77% seizure detection for Data Set I. The detection system was further validated using the model trained by Data Set I on Data Set II. The system again showed high performance, with 91.18% detection of spikes and 99.22% seizure detection. CONCLUSION: We report a de novo EEG classification system for seizure and spike detection on multichannel EEG that includes physiology-based knowledge to enhance the performance of this type of system.

Optimization of fermentation conditions and rheological properties of exopolysaccharide produced by deep-sea bacterium Zunongwangia profunda SM-A87.

Zunongwangia profunda SM-A87 isolated from deep-sea sediment can secrete large quantity of exopolysaccharide (EPS). Response surface methodology was applied to optimize the culture conditions for EPS production. Single-factor experiment showed that lactose was the best carbon source. Based on the Plackett-Burman design, lactose, peptone and temperature were selected as significant variables, which were further optimized by the steepest ascent (descent) method and central composite design. The optimal culture conditions for EPS production and broth viscosity were determined as 32.21 g/L lactose, 8.87 g/L peptone and an incubation temperature of 9.8°C. Under these conditions, the maximum EPS yield and broth viscosity were 8.90 g/L and 6551 mPa•s, respectively, which is the first report of such high yield of EPS from a marine bacterium. The aqueous solution of the EPS displayed high viscosity, interesting shearing thinning property and great tolerance to high temperature, a wide range of pH, and high salinity.

[Biosorption of Pb2+ and Cu2+ by an exopolysaccharide from the deep-sea psychrophilic bacterium Pseudoalteromonas sp. SM9913].

Biosorption of Pb2+ and Cu2+ by exopolysaccharide (EPS) from the deep-sea psychrophilic bacterium Pseudoalteromonas sp. SM9913 was investigated. The influence of EPS dosage, pH, equilibrium time and coexisted-ions on adsorption property and the adsorption isotherm of this EPS were studied. The results show that the equilibrium adsorption capacity (Qe) decreases with the increase of EPS dosage. The optimum pH for the adsorption of Pb2+ is 4.5-5.5, and for the adsorption of Cu2+ is 4.5-6.0. The adsorption equilibrium of Cu2+ onto the EPS is attained within 90 min, while the Pb2+ adsorption equilibrium time is 180 min. Qe of Pb2+ decreases with the addition of coexisted-ions such as Ca2+, Mg2+, Na+ and K+. Addition of Ca2+, Mg2+ also decreases the Qe of Cu2+, but low dosage of Na+ and tested dosage of K+ increase the Qe of Cu2+. Both Freundlich and Dubinin-Radushkevich isotherm equations could well describe the thermodynamics process of Pb2+ and Cu2+ adsorbed onto the EPS. The maximum adsorption capacity of the EPS determined by Dubinin-Radushkevich isotherm equation for Pb2+ and Cu2+ are 243.3 mg/g (10 degrees C) and 36.7 mg/g (40 degrees C), respectively. IR analysis demonstrates that the group of C--O--C, acetyl and hydroxyl of polysaccharide are the main functional groups for binding metal ions.

Color removal from dye-containing wastewater by magnesium chloride.

Color removal by MgCl(2) when treating synthetic waste containing pure dyes was studied. The color removal efficiency of MgCl(2)/Ca(OH)(2) was compared with that of Al(2)(SO(4))(3), polyaluminum chloride (PAC) and FeSO(4)/Ca(OH)(2). The mechanism of color removal by MgCl(2) was also investigated. The experimental results show that the color removal efficiency of MgCl(2) is related to the type of dye and depends on the pH of the waste and the dosage of the coagulants used. Treatment of waste containing reactive dye or dispersed dye with MgCl(2) yielded an optimum color removal ratio when the pH of the solution was equal to or above 12.0. For both the reactive and dispersed dye waste, MgCl(2)/Ca(OH)(2) was shown to be superior to MgCl(2)/NaOH, Al(2)(SO(4))(3), PAC and FeSO(4)/Ca(OH)(2) for color removal. A magnesium hydroxide precipitate formed at pH values greater than 12.0, which provided a large adsorptive surface area and a positive electrostatic surface charge, enabling it to remove the dyes through charge neutralization and an adsorptive coagulating mechanism. So, the MgCl(2)/Ca(OH)(2) system is a viable alternative to some of the more conventional forms of chemical treatment, especially for treating actual textile waste with high natural pH.