Chiral Transfer of Linear Polysiloxane with Preferred-Handed Helical Conformation.

We report the preparation of chiral silica using a linear polysiloxane main chain with a preferred-handed helical structure as the template. Poly(methylvinyl siloxane) (PMVS) with a cysteine derivative side chain designated as PMVS-Cys was prepared using anionic polymerization and an ene-thiol reaction. PMVS-Cys forms a helical conformation in both solution and film via hydrogen bonding between amide groups at side chains. The helical structure remains during the calcination process, resulting in silica with helical structure. The silica with a helical structure shows optical activity.

Optimized aeration strategies for nitrogen removal efficiency: application of end gas recirculation aeration in the fixed bed biofilm reactor.

Aeration strategy played an important role in reactor performance. In this study, when superficial upflow air velocity (SAV) decreased from 0.16 to 0.08 cm s-1, low dissolved oxygen concentration (DO) of 2.0 mg L-1 occurred in reactor. The required depth for anoxic microenvironment in biofilm decreased from 902.3 to 525.9 µm, which enhanced the growth of denitrifying bacteria and total nitrogen (TN) removal efficiency. However, decreasing aeration intensity resulted in insufficient hydraulic shear stress, which led to weak biofilm matrix structure. Mass biofilm detachment and reactor deterioration then occurred after 87 days of operation. An end gas recirculation aeration strategy was proposed to separately manipulate DO and aeration intensity. Low DO and high aeration intensity were simultaneously achieved, which enhanced the metabolism of denitrifying bacteria (such as Flavobacterium sp., Pseudorhodobacter sp., and Dok59 sp.) and EPS-producing bacteria (such as Zoogloea sp. and Rhodobacter sp.). Consequently, high TN removal performance (82.1 ± 2.7%) and stable biofilm structure were achieved.

Forecasting of oil-spill trajectories by using SCHISM and X-band radar.

In this study, we propose a two-step strategy for tracking oil-spill trajectories. First, an X-band radar is established to monitor oil spills. Accordingly, we propose a radar image-processing technique for identifying the oil slicks from the nautical radar images. Second, we apply the SCHISM to determine the water surface elevations and currents at the event site and obtain the trajectories of the oil slicks using a Lagrangian particle-tracking method incorporated in the SCHISM. An oil-spill event caused by the container ship T. S. Taipei is used as a case study for testing the capability of the proposed oil-tracking strategy. The SCHISM simulation results for the fouled coastline obtained using the wind data from a nearby data buoy agree quite well with those obtained from field observations. However, the predicted fouled coastline based on the forecasted wind data is unsatisfactory. The reasons for the unsatisfactory prediction are discussed and revealed.

Steroid hormones (17beta-estradiol and hydrocortisone) upregulate hepatocyte nuclear factor (HNF)-3beta and insulin-like growth factors I and II expression in the gonads of tilapia (Oreochromis mossambicus) in vitro.

Hepatocyte nuclear factors (HNF-1alpha, -1beta and -3beta) and insulin-like growth factors (IGF-I and -II), which are involved in liver-specific gene expression, metabolism, development and cell growth, have been found in the gonads of tilapia (Oreochromis mossambicus). However, the functions of these factors and how they interact within the gonads of bony fish are not understood. In the present study, we provided experimental evidence that the expression of HNF-3beta in the gonads of tilapia, but not HNF-1alpha and -1beta, was affected in vitro by 17beta-estradiol and hydrocortisone. Immunohistochemical staining confirmed that tilapia HNF-3beta was mainly found in the nuclei of hepatocytes, the follicular granulosa cells of the ovaries, and the interstitial cells of the testes of adult tilapia. Further data were gathered at various steroid concentrations (0.1, 1, 10, 100, and 1000 nM) over various culture intervals (6, 12, 18, 24, 30, and 36 h) and subjected to semi-quantitative RT-PCR analysis. The expression of downstream genes (IGF-I and -II) followed the same temporal patterns as HNF-3beta, albeit at decreased levels for 30 and 36 h culture intervals. Both hormones upregulated HNF-3beta mRNA expression at concentrations of 0.1-10 nM, and reached optimal physiological concentrations for induction of IGFs at 1-10 nM. The identity of the PCR fragments was concurrently verified by sequencing and PCR-Southern hybridization. We inferred that HNF-3beta and IGFs may play a regulatory role in tilapia gonads during oocyte maturation and spermatogenesis.