Effect of inclusion of blue-green algae meal on growth and accumulation of microcystins in gibel carp (Carassius auratus gibelio)

Six isonitrogenous (crude protein content: 38%) and isoenergetic (gross energy content: 17 kJ g(-1)) diets were formulated to investigate the effects of inclusion of blue-green algae meal on gibel carp (Carassius auratus gibelio). In each diet, 15% of the protein was supplied by fishmeal; the remainder was supplied by soybean meal and blue-green algae meal. Diet 1 was used as control with no blue-green algae meal whereas the content in diets 2-6 was 15.15, 29.79, 44.69, 59.58 and 74.48%, respectively. Each diet was fed to five groups of gibel carp for 12 weeks in a flow-through system. Final body weight and specific growth rate (SGR) of fish fed diet 5 were significantly lower than the control diet (P < 0.05). Mortality of gibel carp increased with increase in algae meal inclusion (P < 0.05), but there was no significant difference between fish fed diets 3-6 (P > 0.05). Feed conversion efficiency (FCE) decreased with the increase in algae meal inclusion (P < 0.05). Fish-fed diet 6 showed the highest feeding rate (P < 0.05), while there were no significant differences among the other groups (P > 0.05). Apparent digestibility coefficient of dry matter, protein, and energy decreased with increasing algae meal inclusion in the diets (P < 0.05). Aspartate aminotransferase (GOT) activity in the liver was not significantly different among groups (P > 0.05). Liver alanine aminotransferase (GPT) activity of fish-fed diets 4, 5 and 6 was significantly lower than the control diet (diet 1; P < 0.05). Microcystins in the muscle, liver, gallbladder, and spleen increased with increasing algae inclusion (P < 0.05).

Inhibition of progesterone receptor activity in recombinant yeast by soot from fossil fuel combustion emissions and air particulate materials

Numerous environmental pollutants have been detected for estrogenic activity by interacting with the estrogen receptor, but little information is available about their interactions with the progesterone receptor. In this study, emission samples generated by fossil fuel combustion (FFC) and air particulate material (APM) collected from an urban location near a traffic line in a big city of China were evaluated to interact with the human progesterone receptor (hPR) signaling pathway by examining their ability to interact with the activity of hPR expressed in yeast. The results showed that the soot of a petroleum-fired vehicle possessed the most potent anti-progesteronic activity, that of coal-fired stove and diesel fired agrimotor emissions took the second place, and soot samples of coal-fired heating work and electric power station had lesser progesterone inhibition activity. The anti-progesteronic activity of APM was between that of soot from petroleum-fired vehicle and soot from coal-fired establishments and diesel fired agrimotor. Since there was no other large pollution source near the APM sampling sites, the endocrine disrupters were most likely from vehicle emissions, tire attrition and house heating sources. The correlation analysis showed that a strong relationship existed between estrogenic activity and anti-progesteronic activity in emissions of fossil fuel combustion. The discoveries that some environmental pollutants with estrogenic activity can also inhibit OR activity indicate that further studies are required to investigate potential mechanisms for the reported estrogenic activities of these pollutants. (c) 2005 Elsevier B.V. All rights reserved.

Discharges and sediments as sources of extracellular alkaline phosphatase in a shallow Chinese eutrophic lake

Total alkaline phosphatase activity (APA) and soluble reactive phosphorus (SRP) concentrations were measured in municipal wastewater, and a shallow Chinese freshwater lake receiving it. Activities of Dissolved alkaline phosphatase ( ADAP) in overlying and interstitial water were also analyzed monthly at three sites for several years. The lake was enriched with SRP and alkaline phosphatase by discharge of the wastewater, indicating that the inclusion of APA for estimating water pollution was reasonable. Annual data showed that APA in coarser fraction was significantly higher at the site receiving more wastewaters, both in surface and overlying water, suggesting that resuspension of enzyme most likely occurred in the basin heavily discharged. ADAP was an order of magnitude higher in the wastewater than those in lake waters, and was generally higher in interstitial water, a feature more striking at the site receiving more discharges. Besides, it was irrespectively inhibited by Na2WO4, L-cysteine and EDTA-Na, but stimulated by Cu2+, Zn2+, CTAB and Triton X-100 in interstitial, overlying and surface waters. This similarity of responding patterns to the stressors indicated an analogy between dissolved alkaline phosphatase in water column and that in interstitial water, supporting the hypothesis that the polluted sediments act as source of dissolved alkaline phosphatase in eutrophic lakes.

Differing estrogen activities in the organic phase of air particulate matter collected during sunny and foggy weather in a Chinese city detected by a recombinant yeast bioassay

Total air suspended particles (PM 100) collected from an urban location near a traffic line in Wuhan, China, were examined for estrogen using a recombinant yeast bioassay. Wuhan, located at the central part of China, is the fourth biggest city in China with 7 million populations. Today, Wuhan has developed into the biggest city and the largest traveling center of central China, becoming one of the important bases of industry, education and research. Wuhan is right at the confluent point of Yangzi River, the third longest river in the world, and its largest distributary Hanjiang, with mountains and more than 100 takes in downtown area. Therefore, by its unique landscape, Wuhan has formed clear four seasons with relatively long winter and summer and short spring and autumn. Foggy weather usually happen in early spring. The yeast line used in this assay stably expresses human estrogen receptor-alpha. Weak but clear estrogenic activities were detected in the organic phase of crude extracts of air particle materials (APM) in both sunny and foggy weather by 0.19-0.79 mug E2/gPM(100) which were statistically significantly elevated relative to the blank control responding from 20% to 50% of the maximum E2 response, and the estrogenic activity was much higher in foggy weather than in sunny weather. The estrogenic activities in the sub-fractions from chromatographic separation of APM sampled in foggy days were also determined. The results indicated that the responses of the fractions were obviously higher than the crude extracts. Since there is no other large pollution source nearby, the estrogenic material was most likely from vehicle emissions, house heating sources and oil fumes of house cooking. The GC/MS analysis of the PM100 collected under foggy weather showed that there were many phenol derivatives, oxy-PAHs and resin acids which have been reported as environmental estrogens. These results of the analysis of estrogenic potency in sunny and foggy weather in a subtropical city of China indicate that further studies are required to investigate the actual risks for the associated health and atmospheric system. (C) 2004 Elsevier Ltd. All rights reserved.

Quantitative structure-property relationships for octanol-air partition coefficients of polychlorinated naphthalenes, chlorobenzenes and p,p '-DDT

The octanol-air partition coefficient (K-OA) is a key descriptor of chemicals partitioning between the atmosphere and environmental organic phases. Quantitative structure-property relationships (QSPR) are necessary to model and predict KOA from molecular structures. Based on 12 quantum chemical descriptors computed by the PM3 Hamiltonian, using partial least squares (PLS) analysis, a QSPR model for logarithms of K-OA to base 10 (log K-OA) for polychlorinated naphthalenes (PCNs), chlorobenzenes and p,p'-DDT was obtained. The cross-validated Q(cum)(2) value of the model is 0.973, indicating a good predictive ability of the model. The main factors governing log K-OA of the PCNs, chlorobenzenes, and p,p'-DDT are, in order of decreasing importance, molecular size and molecular ability of donating/accepting electrons to participate in intermolecular interactions. The intermolecular dispersive interactions play a leading role in governing log K-OA. The more chlorines in PCN and chlorobenzene molecules, the greater the log K-OA values. Increasing E-LUMO (the energy of the lowest unoccupied molecular orbital) of the molecules leads to decreasing log K-OA values, implying possible intermolecular interactions between the molecules under study and octanol molecules. (C) 2002 Elsevier Science Ltd. All rights reserved.

Quantitative relationships between molecular structures, environmental temperatures and octanol-air partition coefficients of PCDD/Fs

A concise quantitative model that incorporates information on both environmental temperature M and molecular structures, for logarithm of octanol-air partition coefficient (K-OA) to base 10 (logK(OA)) of PCDDs, was developed. Partial least squares (PLS) analysis together with 14 quantum chemical descriptors were used to develop the quantitative relationships between structures, environmental temperatures and properties (QRSETP) model. It has been validated that the obtained QRSETP model can be used to predict logK(OA) of other PCDDs. Molecular size, environmental temperature (T), q(+) (the most positive net atomic charge on hydrogen or chlorine atoms in PCDD molecules) and E-LUMO (the energy of the lowest unoccupied molecular orbital) are main factors governing logK(OA) of PCDD/Fs under study. The intermolecular dispersive interactions and thus the size of the molecules play a leading role in governing logK(OA). The more chlorines in PCDD molecules, the greater the logK(OA) values. Increasing E-LUMO values of the molecules leads to decreasing logK(OA) values, implying possible intermolecular interactions between the molecules under study and octanol molecules. Greater q(+) values results in greater intermolecular electrostatic repulsive interactions between PCDD and octanol molecules and smaller logK(OA) values. (C) 2002 Elsevier Science B.V. All rights reserved.

Quantitative structure-property relationships for octanol-air partition coefficients of polychlorinated biphenyls

Based on nine quantum chemical descriptors computed by PM3 Hamiltonian, using partial least squares analysis, a significant quantitative structure-property relationship for the logarithm of octanol-air partition coefficients (log K-OA) of polychlorinated biphenyls (PCBs) was obtained. The cross-validated Q(cum)(2) value of the model is 0.962, indicating a good predictive ability. The intermolecular dispersive interactions and thus the size of the PCB molecules play a key role in governing log K-OA. The greater the size of PCB molecules, the greater the log K-OA values. Increasing E-LUMO (the energy of the lowest unoccupied molecular orbital) values of the PCBs leads to decreasing log K-OA values, indicating possible interactions between PCB and octanol molecules. Increasing Q(Cl)(+) (the most positive net atomic charges on a chlorine atom) and Q(C)(-) (the largest negative net atomic charge on a carbon atom) values of PCBs results in decreasing log K-OA values, implying possible intermolecular electrostatic interactions between octanol and PCB molecules. (C) 2002 Elsevier Science Ltd. All rights reserved.

Selection and ultrastructural observation of a high-CO2-requiring mutant of cyanobacterium Synechococcus sp PCC7942

A high-CO2-requiring mutant of Synechococcus sp. PCC7942 las been isolated after chemical mutagenesis of ethyl methane sulphonate (EMS). It was able to grow at 4% CO2, but not under ambient CO2. The initial screening of the mutant showed that the genetic reversion rate was about 10(-7) and death occurred 2 -3 days after being transferred from 4% CO2 to the ambient air. Its photosynthetic dependence on external dissolved inorganic carbon was higher than that of the wild type cells, but its carbonic anhydrase activity was comparatively low. In the ultrastructural level, various types of aberrant carboxysomes appeared in the mutant cells: rod-shaped carboxysomes, irregular carboxysomes and the "empty-inclusion carboxysomes" with increasing number of glycogen granules surrounding the thylakoids. All these alterations indicated that the mutant was defective in utilizing the external CO2. The induction of carboxysomes by lower levels of CO2 and the biogenesis of carboxysomes are herein discussed.

Proposal of an Ultracompact Triplexer Using Photonic Crystal Waveguide with an Air Holes Array

We propose an ultracompact triplexer based on a shift of the cutoff frequency of the fundamental mode in a planar photonic crystal waveguide (PCW) with a triangular lattice of air holes. The shift is realized by modifying the radii of the border holes adjacent to the PCW core. Some defect holes are introduced to control the beam propagation. The numerical results obtained by the finite-difference time-domain method show that the presented triplexer can separate three specific wavelengths, i.e. 1310, 1490 and 1550 nm with the extinction ratios higher than - 18 dB. The designed device with a size as compact as 12 mu m x 6.5 mu m is feasible for the practical application, and can be utilized in the system of fiber to the home.

Fabrication of nanoscale metallic air-bridges by introducing a SiO2 sacrificial layer

A new method to fabricate nanoscale metallic air-bridges has been investigated. The pillar patterns of the air-bridge were defined on a SiO2, sacrificial layer by electron-beam lithography combined with inductively coupled plasma etching. Thereafter, the span (suspended part between the pillars) patterns were defined with a second electron-beam exposure on a PMMA/PMMA-MAA resist system. The fabrication process was completed by subsequent metal electron-beam evaporation, lift-off in acetone, and removal of the sacrificial layer in a buffered hydrofluoric (HF) solution. Air-bridges with two different geometries (line-shaped and cross-shaped) were studied in detail. The narrowest width of the air-bridges was around 200 nm, and the typical length of the air-bridges was 2-5 mu m. The advantages of our method are the simplicity of carrying out electron-beam exposure with good reproducibility and the capability of more accurate control of the pillar sizes and shapes of the air-bridge. (C) 2007 Elsevier Ltd. All rights reserved.

Sterilization system for air purifier by combining ultraviolet light emitting diodes with TiO2

BACKGROUND: Ultraviolet light emitting diodes (UV LEDs) were used as a light source in TiO2 photocatalysis because of their many advantages, such as, long life, safety, low pollution, etc. In this experiment, a light source panel was successfully fabricated with UV LEDs, the light intensities of which were relatively uniform.

Determining of the delay time for a heating ventilating and air-conditioning plant using two weighted neural network approach

This paper presents an two weighted neural network approach to determine the delay time for a heating, ventilating and air-conditioning (HVAC) plan to respond to control actions. The two weighted neural network is a fully connected four-layer network. An acceleration technique was used to improve the General Delta Rule for the learning process. Experimental data for heating and cooling modes were used with both the two weighted neural network and a traditional mathematical method to determine the delay time. The results show that two weighted neural networks can be used effectively determining the delay time for AVAC systems.

Optical interleaver based on directional coupler in a 2D photonic crystal slab with triangular lattice of air holes

A small-size optical interleaver based on directional coupler in a 2D photonic crystal slab with triangular lattice of air holes is designed and theoretically simulated using plane wave expansion and finite-difference time-domain method. The interleaver is formed by two parallel and identical photonic crystal slab waveguides which are separated by three rows of air holes. The coupling region is designed below the light line to avoid vertical radiation. The simulated results show that the coupling coefficient is increased and the final length of the interleaver is decreased by enlarging the radius of the middle row of air holes. The transmission properties are analyzed after the interleaver's structure is optimized, and around 100 GHz channel spacing can be got when the length of the interleaver is chosen as 40.5 mu m. (c) 2006 Elsevier B.V. All rights reserved.