Li Ho Tseng

Developmental exposure to decabrominated diphenyl ether (BDE‐209): Effects on sperm oxidative stress and chromatin dna damage in mouse offspring

Polybrominated diphenyl ethers (PBDEs) are used as brominated flame retardants and have been found in human milk in recent years. This study investigates whether prenatal exposure to decabrominated diphenyl ether (BDE‐209) induces sperm dysfunction in male offspring. Pregnant CD‐1 mice were gavaged once daily with corn oil (control), 10, 500, and 1500 mg kg−1 body weight of BDE‐209 from day 0 of gestation to day 17. The outcomes of male reproductive parameters were assessed on postnatal day 71. Anogenital distance, sperm‐head abnormalities, and testicular histopathology were significantly affected in male offspring prenatally exposed to 1500 mg kg−1. Significant increases in the tendency for sperm DNA denaturation (αT) induction and the DNA fragmentation index (DFI) were found in those exposed to 10, 500, and 1500 mg kg−1 (P < 0.05). We observed a significant increase of sperm hydrogen peroxide (H2O2) generation in the 10 and 1500 mg/kg/day groups compared to the control group (P < 0.05). Although our findings suggested that the mechanisms underlying BDE‐209‐induced sperm DNA damage and H2O2 generation might not be represented as a dose‐response relationship, we found that the greater the excess production of sperm H2O2, the greater the sperm αT (r = 0.65, P = 0.0155) and DFI (r = 0.53, P = 0.002). In conclusion, developmental exposure to BDE‐209 induced sperm‐head abnormality, oxidative stress, chromatin DNA damage, and testicular histopathological changes. These findings suggest that BDE‐209‐induced male reproductive effects might involve the formation of sperm H2O2 which attacks nucleic acids via H2O2 generation.

An EEG Investigation of the Impact of Noise on Attention

During the past two decades, most researchers employed a questionnaire to characterize the effect of noise on psychosomatic responses. Developments in physiological techniques offer a non-invasive method for recording brain activity with electroencephalography (EEG). This method for assessing the impact of noise on attention is growing in popularity. The aim of this study was to investigate brain activity changes in response to noise exposure during attention-demanding tasks by using EEG power and phase coherence estimation. We hypothesized that brain rhythms could be affected by environmental stimuli and would be reflected in the EEG power and phase coherence. Nineteen healthy right-handed university students (mean age = 21.5 ± 2.0 years) participated in this study. The experiment comprised recording EEG data for participants in the following steps: rest with eyes closed (< 50 dBA), rest with eyes open, listening in a noisy environment (85 dBA), performance on an attention-demanding task in a quiet environment (< 50 dBA), and performance on an attention-demanding task in a noisy environment (85 dBA). Significant differences were observed between stages, and the participants performed more effectively in the quiet environment, where they showed higher rates of correct responses (p <.05). From the assessment of the EEG power and phase coherence estimation, the study demonstrated the following: (1) Alpha-2 (10-13 Hz) power and phase coherence decreased when participants shifted from closed eyes to open eyes, while theta power increased. (2) In contrast, during the noise exposure phase, whether during an attention-demanding task or not, beta (13-30 Hz) phase coherence decreased in the brain, but theta phase coherence was not affected compared to the results in the quiet environment. We suggest that the high frequency of neural synchronization is relevant for cognitive performance, and that participants at risk for selective attention are affected by noise exposure.

Nitrogen and Phosphorus Removal and Biomass Production by the Green Microalgae in Piggery Wastewater

Use of microalgae to remove inorganic nutrients from wastewater and their great potential for low-cost biomass production is gaining attraction. The effect of piggery wastewater content, aeration rate, cultivation temperature, and light intensity on nitrogen and phosphorus removal and biomass production were studied by using a Box-Behnken experimental design under full factorial methodology. Under experimental conditions considered cultures with aeration increased the ammonium and orthophosphate removal efficiency up to an average of 65.3±17 % and 51±7.2 %, respectively and an increase of biomass productivity ranging from 20.8±11 mg/L.d to 52.3±5.5 mg/L.d. The aeration rate was the most important factor influencing the nutrients removal and biomass production.

Seasonal Variations of Heavy Metals in the Bivalve’s mollusks from Ta-Peng Bay Lagoon in Southwestern Taiwan

Ta-Peng Bay lagoon in southwestern coast of Taiwan belonging to a shallow, productive, coastal lagoon was heavily polluted by the effluent of agriculture from fisheries and domestic sewage. This area provided a plentiful bivalves mollusks for regional market, including Anadara antiquate, Katelysia hiantina, Perna viridis and Anomalocardia squamosa. For understanding correlation between heavy metals existed in aquatic product and variation of heavy metal varied with season, during Dec., 2005- Sep., 2006, six heavy metals, such as Cu, Zn, Pb, Ni, Cr and Cd were analyzed by an air-acetylene flame / Graphite Atomizer atomic absorption spectrophotometer. The variations of different heavy metals existed in aquatic product in season were evaluated using multivariate analysis. Results show that the mean concentration of heavy metal in soft tissues for six aquatic products, Cd species had the lowest value than the others, and Cu and Zn were significantly higher than the other elements. The relationships of all heavy metal species in seasonal variations showed significant dependence. High concentrations of heavy metals were observed in winter. The negative correlation coefficient (p < 0.05) between heavy metals content and season variations statistically revealed decreased with season series for Ni, Pb, and Cr. An interesting finding that Cd bioaccumulation among the species had a significant discrepancy was observed. It means that bivalves mollusks could be develped as a potetial tool for monitoring Cd species.

Effects of Chlorine Dioxide on the Bioactivity of Planktonic and Attached Bacteria Grown in Annular Reactor System

Annular reactor; Epifluorescent microscope; Adenosine triphosphate(ATP)；Chlorine dioxide; Abstract: The artificial solution, including organic molecular weight cut-off less than 5 K added indigenous bacteria taken from biofilter conducted in bench-scale experiment, was drawn by peristaltic pump pumped into Annular Reactor system (ARs) with flow rate 20 mL/min and rotating velocity of 134 rpm. ARs could reach stable at the operational time of 40 hrs. Then, chlorine dioxide was added into ARs to keep system consisting of three chlorine dioxide dosages , including 0.5, 1.0 and 1.5 mg-ClO2 as Cl2/L. Live-Dead microorganisms in this research were measured using both kinds of dye, such as CTC (5-cyano-2,3-diolyl tetrazolium chloride) and DAPI (4’,6-Diamidino-2-phenylindole dihydrochloride), observed under fluorescence microscopy having G-2A filter (EX 510-560 nm, DM 575, BA 590 nm) for CTC, and UV-2A (UV-2A (EX 330-380 nm, DM 400 nm, BA 420 NM) for DAPI. Of course, the measurement of ATP (Adenosine triphosphate) was used as another parameter to evaluate the bacterial activity. Current data shows that when initial chlorine dioxide of 0.2 mg-ClO2asCl2 /L could not effectively control the bacterial cells, especially that the remaining dosage decreased to zero at longer reaction time. In contrast with low chlorine dioxide dosage, 1.0-1.5 mg-ClO2asCl2 /L could not only control the planktonic bacteria but also inhibit the growth of respiring cell attached on the slide. Parameter using Dead-Live cells and ATP to express bacterial activity could show the similar performance while chlorine dioxide was applied into ARs.