Differences in bioaccumulation and transfer ability between tributyltin and triphenyltin from parental female to offspring in viviparous surfperch Ditrema temmincki

To examine the risk of transgenerational transfer of organotin compounds (OTs) in fish, tributyltin (TBT) and triphenyltin (TPT) compounds and their breakdown products were determined in both parental females and offspring of viviparous surfperch Ditrema temmincki collected from Japanese coastal waters. TBT concentrations (Mean ± SD) in the offspring (34 ± 5.7 ng Sn g−1 wet wt) were significantly higher (10–17 times) than in the parental females (2.8 ± 1.0 ng Sn g−1 wet wt). In the offspring, TBT was the predominant butyltin compound (82 ± 1.6% ∑BTs = TBT + DBT + MBT), and represented a greater proportion than in the parental females (51 ± 9.3% as TBT). TPT concentrations were significantly lower than TBT, and the ratio of TPT in parental females, relative to offspring, was different from TBT. TPT concentrations in the offspring (0.8 ± 0.3 ng Sn g−1 wet wt) were almost identical to those in the parental females (1.0 ± 0.5 ng Sn g−1 wet wt). TPT was the predominant phenyltin (∑PTs = TPT + DPT + MPT) in both offspring (73 ± 12% as TPT) and parental females (72 ± 18% as TPT). Results suggest that the transfer rate of TBT from parent to offspring could be much faster than its degradation rate in the offspring, accounting for higher accumulation of TBT in the latter. In contrast, the transfer rate of TPT is slower than its biodegradation, leading to a lower concentration of TPT in the offspring. It is therefore likely that the offspring might be at a higher risk from TBT than the parental females during their early growth stage in ovary in the viviparous surfperch whereas exposure to TPT is comparable in both generations

Conveyance Test by Oscillation and Rotation to a Permanent Magnet Repulsive-Type Conveyor

Various applications of a single-axis controlled repulsive-type magnetic bearing have been proposed earlier. However, most conventional systems are equipped with a set of passive magnetic bearings and an active magnetic bearing. In this paper a new repulsive-type conveyor system with many passive magnetic bearing pairs is proposed. This system enables an easy rotation with negligible friction and soft conveyance by radial stiffness between the rotor and the stator permanent magnets. This paper also reports a conveyance test using ellipse motion of each shaft

Effects of tributyltin on the chlorophyll contents of marine microalga Tetraselmis tetrathele, Nannochloropsis oculata and Dunaliella sp

Three species of marine microalga Tetraselmis tetrathele, Nannochloropsis oculata and Dunaliella sp., the important phyto-plankton in many hatcheries, were used in an acute toxicity test of TBT with emphasis on the chlorophyll a and b contents. After a very short exposure time of three concentrations of TBT, 0.1, 0.5 and 1μgl^, the three species of algae showed different responses. The chlorophyll a and b contents of T. tetrathele in all treatments were higher than those in controls, even be doubled in 1μgl^ of TBT. N. oculata and Dunaliella had a slightly higher chlorophyll a and b contents in the lowest TBT concentration tested (0.1μgl^) than those in control, but as the TBT concentration increased their chlorophyll contents decreased. Three levels of TBT tested are within the range of the no observable effect concentration (NOEC) for T. tetrathele, while the lowest observable effect concentrations (LOEC) for N. oculata and Dunaliella are between 0.1 to 0.5μgl^. Among the three species, N. oculata has a highest sensitivity towards TBT

Effects of triphenyltin exposure on the red alga Eucheuma denticulatum

Toxic effects of triphenyltin (TPT) on the marine alga Eucheuma denticulatum obtained from Nain Island, North Sulawesi, Indonesia have been examined in laboratory condition. The algal samples were first acclimated in laboratory prepared seawater for three days. The algae were then divided into 12 culture chambers for treatments with different concentrations of TPT between 5-30 μgl^ with 5μgl^ interval, and in another container for control. After two-week experimentation, some samples of algae were obtained from each chamber for histopathological examination. The aniline blue stained tissue of alga E. denticulatum showed that at all TPT concentration tested, the cortex had morphological changes, even almost disappeared at higher concentration (>20μgl^). The medullary cells of alga exposed to 5-15μgl^ have been decreasing in size compared to those in control. Cell walls of some medullary cells have damaged at 20μgl^ and totally lysed in all cells of alga exposed to 25 and 30μgl^. The pattern of zonatedly dividing tetrasporangium had not occurred anymore in alga exposed to TPT even at the lowest tested concentration (5μgl^) and had totally damaged in higher concentrations, such as that of 20μgl^. The tetraspores in tetrasporangium seem to be fused or shrinkage, no more dividing process occurred as in control. Therefore, reproductive cells of alga is more sensitive than somatic cells, indicating that no further development of alga will occur in aquatic environment contaminated even with unlethal TPT levels

The effect of non-uniform magnetization of permanent magnets on the performance of a repulsive type magnetic bearing system

A permanent magnet bearing (MB) system utilizing the repulsive forces operating between the stator and rotor permanent magnet for levitation and radial control has been fabricated in our laboratory, The consistency of the permanent magnet magnetization effects the continuous steady-state and dynamic performance of the system. Since both the magnets are repelling each other, there will be demagnetization of the magnetization of the permanent magnet. Due to demagnetization or ageing or manufacturing asymmetry, the field distribution may not be uniform along the periphery of the magnet. In this paper the effect of this magnetization non-uniformity on the performances of the bearing system has been studied

Thrombomodulin expression in colorectal carcinoma is protective and correlates with survival

Thrombomodulin (TM) is an endothelial receptor that exhibits anticoagulant, antifibrinolytic and anti-inflammatory activity by inhibiting thrombin and cellular adhesion. In this study, the expression and significance of TM was examined in primary colorectal cancer and its prognostic implications explored. TM immunostaining was performed on formalin-fixed, paraffin-embedded tissue sections, from primary lesions of 200 patients with colorectal carcinoma. Institutional Ethical approval was granted and clinical data retrieved from patients' records. All normal colonic tissue expressed TM on endothelial cells. TM tumour cell expression was demonstrated in 53 (26.5%) cases and 147 (73.5%) showed no neoplastic cell staining. On univariate and multivariate analysis TM expression on tumour cells correlated significantly with tumour stage, differentiation, Jass score and 5 year survival. TM expression decreases as overall stage and tumour size increase (P=0.03). In all, 91% TM positive tumours were well differentiated and 85% of TM negative tumours were poorly differentiated (P<0.01). Five year survival rates of patients with positive and negative TM expression were 71 and 41%, respectively. Survival rate was poorer in those patients who were TM negative compared with those who were positive (P<0.01). A total of 101 (50.5%) of the cases were node negative. In this group, 5 year survival rates of patients with positive and negative TM expression were 87.5 and 37.8%, respectively, demonstrating a poorer survival rate for those who are node negative and TM negative at the time of surgery (P<0.001). This study demonstrates that loss of TM is a key indicator in tumour biology and prognosis