Compensatory growth in hybrid tilapia, Oreochromis mossambicus x O-niloticus, reared in seawater

Hybrid tilapia weighing 4.34 +/- 0.03 g (mean +/- SE) were reared in seawater at 23.8 to 27.0 degrees C for 8 weeks. The control group was fed to satiation twice a day throughout the experiment. The other three groups were deprived of feed for 1, 2, and 4 weeks, respectively, and then fed to satiation during the refeeding period. At the end of the experiment, fish deprived for 1 week had similar body weights to the controls, whereas fish deprived for 2 and 4 weeks had significantly lower body weights than the controls. During the refeeding period, size-adjusted feed intakes and specific growth rates were significantly higher in deprived fish than in the controls, indicating some compensatory responses in these fish. Feed intake and growth rate upon refeeding were higher the longer the duration of deprivation. No significant differences were found in digestibility, feed efficiency or protein and energy retention efficiency between the deprived and control fish during refeeding, suggesting that hyperphagia was the mechanism responsible for increased growth rates during compensatory growth. During refeeding, relative gains in protein, lipid and ash, as proportions of total body weight gain, did not differ significantly among treatment groups. (C) 2000 Elsevier Science B.V. All rights reserved.

Fabrication of ZnO and its enhancement of charge injection and transport in hybrid organic/inorganic light emitting devices

ZnO nanocrystals were synthesized by hydrolysis in methanol. X-ray diffraction and photoluminescence spectra confirm that good crystallized ZnO nanoparticles were formed. Utilizing those ZnO nanoparticles and poly [2- methoxy-5 - (3',7'-dimethyloctyloxy)- 1,4-phenylenevinylene] (MDMO-PPV), light emitting devices with indium tin oxide (ITO)/poly(3,4-oxyethyleneoxy-thiophene):poly(styrene sulfonate) (PEDOT:PSS)/ ZnO:MDMO-PPV/Al and ITO/PEDOT:PSS/MDMO-PPV/Al structures were fabricated. Electrolummescence (EL) spectra reveal that EL yield of hybrid MDMO-PPV and ZnO nanocrystals devices increased greatly as compared with pristine MDMO-PPV devices. The current-voltage characteristics indicate that addition of ZnO nanocrystals can facilitate electrical injection and charge transport. The decreased energy barrier to electron injection is responsible for the increased efficiency of electron injection. (c) 2007 Elsevier B.V. All rights reserved.

The wave function evolution of an exciton in a bilayer system: Turning on a static in-plane electric field

The time evolution of the ground state wave function of an exciton in an ideal bilayer system is investigated within the framework of the effective-mass approximation. All of the moduli squared of the ground state wave functions evolve with time as cosine functions after an in-plane electric field is applied to the bilayer system. The variation amplitude and period of the modulus squared of the ground state wave function increase with the in-plane electric field F-r for a fixed in-plane relative coordinate r and fixed separation d between the electron and hole layers. Moreover, the variation amplitude and period of the modulus squared of the ground state wave function increase with the separation d for a fixed r and fixed in-plane electric field. Additionally, the modulus squared of the ground state wave function decreases as r increases at a given time t for fixed values of d and F-r. (c) 2007 American Institute of Physics.

Tunable spin transport in magnetic-electric superlattice

We study the spin-dependent electron transport in a special magnetic-electric superlattice periodically modulated by parallel ferromagnetic metal stripes and Schottky normal-metal stripes. The results show that, the spin-polarized current can be well controllable by modulating the magnetic strength of the ferromagnetic stripes or the voltage applied to the Schottky normal-metal stripes. It is obvious that, to the system of the magnetic superlattice, the polarized current can be enhanced by the magnetic strength of ferromagnetic stripes. Nevertheless, it is found that, for the magnetic-electric superlattice, the polarized current can also be remarkably advanced by the voltage applied to the Schottky normal-metal stripes. These results may indicate a useable approach for tunable spintronic devices. (c) 2006 Elsevier B.V. All rights reserved.

High gain in hybrid transistors with BAlq(3)/Alq(3) isotype heterostructure emitter

We report the fabrication of permeable metal-base transistors based on bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-biphenyl-4-olato) aluminum (BAlq(3))/tri(8-hydroxyquinoline) aluminum (Alq(3)) isotype heterostructure as emitter layer. In this transistor, n-Si was used as the collector, LiF/Al as the emitter electrode, and Au/Al bilayer metal as the base. We show that the leakage current is greatly reduced in Al/n-Si/Au/Al/BAlq(3)/Alq(3)/LiF/Al devices with respect to Al/n-Si/Au/Al/Alq(3)/LiF/Al devices due to the utilization of BAlq(3)/Alq(3) isotype heterostructure emitter, leading to high common-base and common-emitter current gains at low driving voltages.

High gain in hybrid transistors with vanadium oxide/tris(8-hydroxyquinoline) aluminum emitter

We report the electrical characterization of hybrid permeable-base transistors with tris(8-hydroxyquinoline) aluminum as emitter layer. These transistors were constructed presenting an Al/n-Si/Au/Alq(3)/V2O5/Al structure. We investigate the influence of the V2O5 layer thickness and demonstrate that these devices present high common-base and common-emitter current gain, and can be operated at very low driving voltages, lower than 1 V, in both, common-base and common-emitter modes.

Noncovalent functionalization of multiwalled carbon nanotubes: Application in hybrid nanostructures

We developed a reproducible, noncovalent strategy to functionalize multiwalled carbon nanotubes (MWNTs) via embedding nanotubes in polysiloxane shells. (3-Aminopropyl)triethoxysilane molecules adsorbed to the nanotube surfaces via hydrophobic interactions are polymerized simply by acid catalysis and form a thin polysiloxane layer. On the basis of the embedded MWNTs, negatively charged gold nanoparticles are anchored to the nanotube surfaces via electrostatic interactions between the protonated amino groups and the gold nanoparticles. Furthermore, these gold nanoparticles can further grow and magnify along the nanotubes through heating in HAuCl4 aqueous solution at 100 degrees C; as a result these nanoparticles are joined to form continuous gold nanowires with MWNTS acting as templates.

Analysis of micro-failure behaviors in hybrid fiber model composites

Micro-failure modes and statistical fragment lengths in the hybrid fiber and non-hybrid reference composites in the uniaxial tension were investigated. Similiar to the reference experiments, fibers in hybrid strong interface/medium interface fiber composites display a decrease in aspect ratio and an increase in interfacial shear stress (IFSS) with the increase of inter-fiber spacing. While for the fibers with weak interfaces in the hybrid strong interface/weak interface fiber composites, the aspect ratio increases and IFSS decreases with enlargement of inter-fiber spacing, which is contrary to other systems. Finite element numerical analysis was used to interpret the special phenomena.

Luminescence properties of lanthanide complexes doped in hybrid material from tetraethoxysilane and 3-glycidyioxyropyl-trimethoxysilane

Hybrid materials, containing in-situ synthesized lanthanide complexes with intense green light, have been prepared via sol-gel process. The luminescence properties and the decay times of as-synthesized samples were investigated. The excitation spectrum of the samples indicates the formation of complexes between terbium (III) and P-Sulfosalicylic acid. The hybrid materials that contain in-situ synthesized terbium complexes exhibit the characteristic emission bands of the rare earth ions. In addition, the effect of concentration of terbium on the luminescence properties as well as the thermal stability were also studied.

Crystallization behavior of PCL in hybrid confined environment

Poly(epsilon -caprolactone) (PCL) and silica (SiO2) organic-inorganic hybrid materials have been synthesized by the sol-gel method. The crystallization behavior of PCL in silica networks has been investigated using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The degree of PCL crystallinity in PCL/SiO2 hybrid networks reduces with increase of SiO2. PCL is in an amorphous state when the concentration of PCL is lower than 40wt% in the hybrid system. The melting point of PCL in the networks is lower than, but close to that of pure PCL. WAXD and SEM results show that the crystalline behavior of PCL in PCL/SiO2 hybrid system is strictly confined. (C) 2001 Elsevier Science Ltd. All rights reserved.

In vivo inhibition of elevated myocardial beta-adrenergic receptor kinase activity in hybrid transgenic mice restores normal beta-adrenergic signaling and function.

BACKGROUND: The clinical syndrome of heart failure (HF) is characterized by an impaired cardiac beta-adrenergic receptor (betaAR) system, which is critical in the regulation of myocardial function. Expression of the betaAR kinase (betaARK1), which phosphorylates and uncouples betaARs, is elevated in human HF; this likely contributes to the abnormal betaAR responsiveness that occurs with beta-agonist administration. We previously showed that transgenic mice with increased myocardial betaARK1 expression had impaired cardiac function in vivo and that inhibiting endogenous betaARK1 activity in the heart led to enhanced myocardial function. METHODS AND RESULTS: We created hybrid transgenic mice with cardiac-specific concomitant overexpression of both betaARK1 and an inhibitor of betaARK1 activity to study the feasibility and functional consequences of the inhibition of elevated betaARK1 activity similar to that present in human HF. Transgenic mice with myocardial overexpression of betaARK1 (3 to 5-fold) have a blunted in vivo contractile response to isoproterenol when compared with non-transgenic control mice. In the hybrid transgenic mice, although myocardial betaARK1 levels remained elevated due to transgene expression, in vitro betaARK1 activity returned to control levels and the percentage of betaARs in the high-affinity state increased to normal wild-type levels. Furthermore, the in vivo left ventricular contractile response to betaAR stimulation was restored to normal in the hybrid double-transgenic mice. CONCLUSIONS: Novel hybrid transgenic mice can be created with concomitant cardiac-specific overexpression of 2 independent transgenes with opposing actions. Elevated myocardial betaARK1 in transgenic mouse hearts (to levels seen in human HF) can be inhibited in vivo by a peptide that can prevent agonist-stimulated desensitization of cardiac betaARs. This may represent a novel strategy to improve myocardial function in the setting of compromised heart function.