Changes in plasma thyroid hormones and cortisol levels in crucian carp (Carassius auratus) exposed to the extracted microcystins

The endocrine response of crucian carp injected intraperitoneally with extracted microcystins (MC) was investigated in this study. Fish were injected intraperitoneally either with 0.75% NaCl (control) and Microcystis extract corresponding to 150 and 600 mu g microcystins per kg body weight. The plasma levels of triiodothyronine (T-3), thyroxine (T-4), free triiodothyronine (FT3), free thyroxine (FT4), and cortisol were determined at 0, 1, 3, 12, 24. and 48 h post-administration of MC-containing extract. Treated fish displayed abnormal behaviors, Such as a startle response and disoriented swimming, as well as changes in ventilation rates. Plasma cortisol concentrations of fish in both dose groups significantly increased after administration of extracted MC and remained high throughout the experiment, which suggested that MC elicited a stress response in treated fish. The profiles of cortisol changes in treated fish appeared to be dose dependent, indicating that fish in the high dose group experienced greater MC-incluced disturbance. Mortality occurred after 12 h in the high dose group. Plasma levels of T-4, T-3, FT4, and FT3 did not vary significantly between the control fish. In contrast to this, fish exposed to MC-containing extract showed significant declines in T-3, FT4, and FT3 levels in a dose-depenclent manner throughout the experiment. Plasma T4 levels, however, did not vary significantly in the low dose group, whereas they decreased significantly it 48 h post injection in the high dose group. This study demonstrates that administration of microcystins-containing extract causes a stress response and reduces the plasma levels of thyroid hormones in crucian carp. These results illustrate that microcystins exerted potent effects on the endocrine system of crucian carp, through activating their hypothalamus-pituitary- interrenal axis and disturbing thyroid function. (c) 2008 Elsevier Ltd. All rights reserved.

Plasma biochemical responses of the omnivorous crucian carp (Carassius auratus) to crude cyanobacterial extracts

Healthy crucian carp (Carassius auratus) were treated by intraperitoneal (i.p.) injection of crude cyanobacterial extracts at two doses, 50 and 200 mu g MC-LR equiv kg(-1) BW. High mortality (100%) was observed within 60 h post injection in the high-dose group. In the treated fish, activities of four plasma enzymes, alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH), all showed substantial increases, with both dose and time-dependent effects. These increases of enzyme activity indicate severe impairment occurred in the liver of crucian carp over time. Plasma concentrations of energy-related biomolecules including glucose (GLU), cholesterol (CHO), triglyceride (TG), and total protein (TP) showed marked changes in the high-dose group, possibly a nutritional imbalance correlated with the liver injury caused by intraperitoneal exposure to crude cyanobacterial extracts.

Quantitative Determination of Microcystins in Rat Plasma by LC-ESI Tandem MS

A rapid and sensitive method was developed and validated for the determination of MCYST (microcystin)-RR, -LR, and [Dha(7)] MCYST-LR in rat plasma by liquid chromatography-tandem mass spectrometry. The analytes were extracted from rat plasma by protein precipitation, followed by solid-phase extraction. Liquid chromatography with electrospray ionization mass spectrometry, operating in selected reaction monitoring (SRM) mode, was used to quantify MCYST-RR, -LR, and [Dha(7)] MCYST-LR in rat plasma. The recoveries for each analyte in rat plasma ranged from 70.8 to 88.7%. The calibration curve was linear within the range from 0.005 to 1.25 mu g mL(-1). The limit of detection were 1.4, 1.0, 0.6 ng mL(-1) for MCYST-RR, -LR, and [Dha(7)] MCYST-LR. The overall precision was determined on three different days. The values for within- and between-day precision in rat plasma were within 15%. This method was applied to the identification and quantification of microcystins in rat plasma with acute exposure of microcystins via intravenous injection.

Hematological and plasma biochemical responses of crucian carp (Carassius auratus) to intraperitoneal injection of extracted microcystins with the possible mechanisms of anemia

Alterations in hematological indices such as decreases in blood cell counts (RBC), hematocrit (Ht) and hemoglobin (Hb) concentrations are key symptoms of anemia. However, few experiments were conducted to examine changes in hematological indices of fish exposed to microcystins that are believed to be fatal to circulatory systems of vertebrates. An acute toxicological experiment was designed to study hematological changes of crucian carp injected intraperitoneally (i.p.) with extracted microcystins at two doses, 50 and 200 mu g MC-LReqkg(-1) body weight. After being i.p. injected with microcystins, the fish exhibited behavioral abnormity. There were significant decreases in RBC in the high-dose group, and in Ht and Hb concentrations in both dose groups, while erythrocte sedimentation rate (ESR) significantly increased, indicating the appearance of normocytic anemia. There were no prominent changes in the three red cell indices, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH,), and mean corpuscular hemoglobin concentration (MCHC). Increases in blood urea nitrogen (BUN) and creatinine (CR) in both dose groups suggest the occurrence of kidney impairment. Alteration in blood indices was reversible at the low dose group. Conclusively, anemia induced by kidney impairment was a key factor to cause abnormity of swimming behaviors and high mortality of crucian carp. (c) 2007 Elsevier Ltd. All rights reserved.

Thermal shock resistance of air plasma sprayed thermal barrier coatings

The spallation resistance of an air plasma sprayed (APS) thermal barrier coating (TBC) to cool-down/reheat is evaluated for a pre-existing delamination crack. The delamination emanates from a vertical crack through the coating and resides at the interface between coating and underlying thermally grown oxide layer (TGO). The coating progressively sinters during engine operation, and this leads to a depth-dependent increase in modulus. Following high temperature exposure, the coating is subjected to a cooling/reheating cycle representative of engine shut-down and start-up. The interfacial stress intensity factors are calculated for the delamination crack over this thermal cycle and are compared with the mode-dependent fracture toughness of the interface between sintered APS and TGO. The study reveals the role played by microstructural evolution during sintering in dictating the spallation life of the thermal barrier coating, and also describes a test method for the measurement of delamination toughness of a thin coating. © 2014 Elsevier Ltd.

High rate deposition of microcrystalline silicon films by high-pressure radio frequency plasma enhanced chemical vapor deposition (PECVD)

Hydrogenated microcrystalline silicon (mu c-Si:H) thin films were prepared by high-pressure radio-frequency (13.56 MHz) plasma enhanced chemical vapor deposition (rf-PECVD) with a screened plasma. The deposition rate and crystallinity varying with the deposition pressure, rf power, hydrogen dilution ratio and electrodes distance were systematically studied. By optimizing the deposition parameters the device quality mu c-Si:H films have been achieved with a high deposition rate of 7.8 angstrom/s at a high pressure. The V-oc of 560 mV and the FF of 0.70 have been achieved for a single-junction mu c-Si:H p-i-n solar cell at a deposition rate of 7.8 angstrom/s.

Evolution of structural defects in SiOx films fabricated by electron cyclotron resonance plasma chemical vapour deposition upon annealing treatment

We study the structural defects in the SiOx film prepared by electron cyclotron resonance plasma chemical vapour deposition and annealing recovery evolution. The photoluminescence property is observed in the as-deposited and annealed samples. [-SiO3](2-) defects are the luminescence centres of the ultraviolet photoluminescence (PL) from the Fourier transform infrared spectroscopy and PL measurements. [-SiO3](2-) is observed by positron annihilation spectroscopy, and this defect can make the S parameters increase. After 1000 degrees C annealing, [-SiO3](2-) defects still exist in the films.

Enhancement of conductivity and transmittance of ZnO films by post hydrogen plasma treatment

We studied the effects of hydrogen plasma treatment on the electrical and optical properties of ZnO films deposited by radio frequency magnetron sputtering. It is found that the ZnO H film is highly transparent with the average transmittance of 92% in the visible range. Both carrier concentration and mobility are increased after hydrogen plasma treatment, correspondingly, the resistivity of the ZnO H films achieves the order of 10(-3) cm. We suggest that the incorporated hydrogen not only passivates most of the defects and/or acceptors present, but also introduces shallow donor states such as the V-O-H complex and the interstitial hydrogen H-i. Moreover, the annealing data indicate that H-i is unstable in ZnO, while the V-O-H complex remains stable on the whole at 400 degrees C, and the latter diffuses out when the annealing temperature increases to 500 degrees C. These results make ZnO H more attractive for future applications as transparent conducting electrodes.

Enhancement of field emission of the ZnO film by the reduced work function and the increased conductivity via hydrogen plasma treatment

The ZnO films deposited by magnetron sputtering were treated by H/O plasma. It is found that the field emission (FE) characteristics of the ZnO film are considerably improved after H-plasma treatment and slightly deteriorated after O-plasma treatment. The improvement of FE characteristics is attributed to the reduced work function and the increased conductivity of the ZnO H films. Conductive atomic force microscopy was employed to investigate the effect of the plasma treatment on the nanoscale conductivity of ZnO, these findings correlate well with the FE data and facilitate a clearer description of electron emission from the ZnO H films.

Inductively coupled plasma etching in fabrication of 2D InP-based photonic crystals

The authors developed an inductively coupled plasma etching process for the fabrication of hole-type photonic crystals in InP. The etching was performed at 70 degrees C using BCl3/Cl-2 chemistries. A high etch rate of 1.4 mu m/min was obtained for 200 nm diameter holes. The process also yields nearly cylindrical hole shape with a 10.8 aspect ratio and more than 85 degrees straightness of the smooth sidewall. Surface-emitting photonic crystal laser and edge emitting one were demonstrated in the experiments.

Bulge testing and fracture properties of plasma-enhanced chemical vapor deposited silicon nitride thin films

The mechanical properties and fracture behavior of silicon nitride (SiNx) thin film fabricated by plasma-enhanced chemical vapor deposition is reported. Plane-strain moduli, prestresses, and fracture strengths of silicon nitride thin film; deposited both oil a bare Si substrate and oil a thermally oxidized Si substrate were extracted using bulge testing combined with a refined load-deflection model of long rectangular membranes. The plane-strain modu i and prestresses of SiNx thin films have little dependence on the substrates, that is, for the bare Si substrate, they are 133 +/- 19 GPa and 178 +/- 22 MPa, respectively, while for the thermally oxidized substrate, they are 140 +/- 26 Gila and 194 +/- 34 MPa, respectively. However, the fracture strength values of SiNx films grown on the two substrates are quite different, i.e., 1.53 +/- 0.33 Gila and 3.08 +/- 0.79 GPa for the bare Si substrate a A the oxidized Si substrate, respectively. The reference stresses were computed by integrating the local stress of the membrane at the fracture over the edge, Surface, and volume of the specimens and fitted with the Weibull distribution function. For SiNx thin film produced oil the bare Si Substrate, the Volume integration gave a significantly better agreement between data and model, implying that the volume flaws re the dominant fracture origin. For SiNx thin film grown on the oxidized Si substrate, the fit quality of surface and edge integration was significantly better than the Volume integration, and the dominant surface and edge flaws could be caused by buffered HF attacking the SiNx layer during SiO2 removal. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.

Amorphous silicon carbide films prepared by H-2 diluted silane-methane plasma

This paper reports on the preparation and characterization of hydrogenated amorphous silicon carbide films prepared by H-2 diluted silane-methane plasma. Carbon-rich a-SiC:H film with band gap of up to 3.3 eV has been achieved. IR and UV Vis spectra were employed to characterize the chemical bonding and optical properties of as-prepared films. It is shown that hydrogen dilution is crucial in obtaining these wide band gap carbon-rich films. Raman and PL measurements were performed to probe the microstructure and photoelectronic properties of these films before and after annealing. Films with intermediate carbon concentration seem more defective and exhibit stronger photoluminescence and subband absorption than others. Films with different compositions exhibit different annealing behaviours. For silicon rich and carbon rich films, high temperature annealing results in the formation of silicon crystallites and graphite clusters, respectively. (C) 2003 Elsevier B.V. All rights reserved.

High speed 2x2 optical switch in silicon-on-insulator based on plasma dispersion effect

Based on free carrier plasma dispersion effect, a 2 x 2 optical switch is fabricated in a silicon-on-insulator substrate by inductively coupled-plasma technology and ion implantation. The device has a Mach-Zehnder interferometer structure, in which two directional couplers serve as the power splitter and combiner. The switch presents an insertion loss of 3.04 dB and a response time of 496 ns.

Boron-doped silicon nanowires grown by plasma-enhanced chemical vapor deposition

Boron-doped ( B-doped) silicon nanowires have been successfully synthesized by plasma-enhanced chemical vapor deposition (PECVD) at 440degreesC using silane as the Si source, diborane( B2H6) as the dopant gas and An as the catalyst. It is desirable to extend this technique to the growth of silicon nanowire pn junctions because PECVD enables immense chemical reactivity.