Thermophilic treatment by anaerobic granular sludge as an effective approach to accelerate the electron transfer and improve the reductive decolorization of azo dyes in bioreactors

The effects of temperature, hydraulic retention time (HRT), and the redox mediator, anthraquinone-2,6-disulfonate (AQDS), on electron transfer and subsequent reductive decolorization of dyes from textile wastewater was assessed in mesophilic and thermophilic anaerobic bioreactors. The results clearly show that compared to mesophilic anaerobic treatment, thermophilic treatment at 55 degrees C is an effective approach for increasing the electron transfer capacity in bioreactors, and thus improving the decolorization rates. At an HRT of 2.5 h and in the absence of AQDS, the color removal was 5.3-fold higher at 55 degrees C compared to 30 degrees C. Furthermore, similar decolorizations were found at 55 degrees C between the AQDS-free and AQDS-supplemented reactors, whereas a significant difference (up to 3.6-fold) on dye reduction occurred at 30 degrees C.

Enhancing the electron transfer capacity and subsequent color removal in bioreactors by applying thermophilic anaerobic treatment and redox mediators

The effect of temperature, hydraulic retention time (HRT) and the redox mediator anthraquinone-2,6-disulfonate (AQDS), on electron transfer and subsequent color removal from textile wastewater was assessed in mesophilic and thermophilic anaerobic bioreactors. The results clearly show that compared with mesophilic anaerobic treatment, thermophilic treatment at 55 degrees C is an effective approach for increasing the electron transfer capacity in bioreactors, and thus improving the decolorization rates. Furthermore, similar color removals were found at 55 degrees C between the AQDS-free and AQDS-supplemented reactors, whereas a significant difference (up to 3.6-fold) on decolorization rates occurred at 30 degrees C. For instance, at an HRT of 2.5 h and in the absence of AQDS, the color removal was 5.3-fold higher at 55 degrees C compared with 30 degrees C. The impact of a mix of mediators with different redox potentials on the decolorization rate was investigated with both industrial textile wastewater and the azo dye Reactive Red 2 (RR2). Color removal of RR2 in the presence of anthraquinone-2-sulfonate (AQS) (standard redox potential E(0)' of -225 mV) was 3.8-fold and 2.3-fold higher at 30 degrees C and 55 degrees C, respectively, than the values found in the absence of AQS. Furthermore, when the mediators 1,4-benzoquinone (BQ) (E(0)' of +280 mV), and AQS were incubated together, there was no improvement on the decolorization rates compared with the bottles solely supplemented with AQS. Results imply that the use of mixed redox mediators with positive and negative E(0)' under anaerobic conditions is not an efficient approach to improve color removal in textile wastewaters.

Anatomical structures in the Leksell pallidotomy target

OBJECTIVE

Because interruption of pallidal outflow signals by pallidotomy is believed to play an important role in the motor improvement in Parkinson's disease, the anatomical relationship of the two major pallidofugal tracts, namely the ansa lenticularis (AL) and the fasciculus lenticularis (FL) to the Leksell pallidotomy target (LPT) were studied.

METHODS

Magnetic resonance (MR) scans of 20 patients with Parkinson's disease were studied. The scans were obtained in the inversion recovery and fast spin echo sequences and viewed in the reverse video mode.

RESULTS

The pallidofugal tracts appeared as bands of high intensity on MR scan. FL was wide and extended from the posterior half of the globus pallidus interna (GPi) medially into the internal capsule. AL was narrow, parallel and posterior to the anterior commissure, parallel to and 3 mm above the optic tract, and just beneath the FL. The part of the FL immediately lateral to the internal capsule overlapped the lateral end of the AL. The center of this overlapping area was termed the 'operlapping point' (OP). In all cases, the OP was within the range of LPT.

CONCLUSION

It is concluded that the structures in the LPT are FL and AL; and therefore, this procedure could also be known as 'fasciculoansatomy'.

Impairments in route negotiation through a maze after dorsolateral frontal, inferior parietal or premotor lesions in cynomolgus monkeys

Ten cynomolgus monkeys were trained to follow a fixed route through a whole-body maze consisting of 3 X 3 matrix of 9 compartments, all with interconnecting doors. Two monkeys learned to use proprioceptive guidance such that they tended to produce the same sequence of movements even if they entered the maze by a different door. They were not impaired by bilateral lesions to inferior parietal cortex (Area 7a/PG). The rest used non-proprioceptive guidance relying on external cues in the environment, probably outside the maze. These were impaired by bilateral lesions of either dorsolateral frontal or posterior parietal cortex. At least 3 different strategies may be used for route negotiation. Postoperative comparisons of the frontal and parietal groups on the effects of rearranging the external cues and on learning a new route through the maze suggested that the groups were differentially impaired in the use of different strategies. In a subsequent study, bilateral lesions to premotor cortex (Area 6) resulted in an impaired ability to follow a route using either proprioceptive or external cues.