Self-powered broadband, high-detectivity and ultrafast photodetectors based on Pd-MoS2/Si heterojunctions.

In this work, a self-powered photodetector device is fabricated through the integration of a palladium-doped molybdenum disulfide thin film on silicon (Pd-MoS2/Si). The substitution of host Mo atoms with Pd dopants in the MoS2 film is revealed by structural and chemical analysis techniques. Due to the incorporation of Pd atoms into the MoS2 films, the photovoltaic characteristics of the fabricated Pd-MoS2/Si device were enhanced largely, promoting its application as a self-powered photodetector operated at zero bias voltage. The obtained results further show that the device is highly sensitive to broadband wavelengths from ultraviolet to near-infrared light (300-1100 nm). In particular, the Pd-MoS2/Si photodetector shows an ultra-high detectivity of ∼10(14) Jones (Jones = cm Hz(1/2) W(-1)), a responsivity of ∼654.0 mA W(-1), and an ultrafast response speed of ∼2.1 µs. The present work opens new avenues for developing high-performance photodetectors for optical communications and imaging techniques as well as optoelectronic circuits.

High-performance n-MoS2/i-SiO2/p-Si heterojunction solar cells.

A solar cell based on the n-MoS2/i-SiO2/p-Si heterojunction is fabricated. The device exhibits a high power-conversion efficiency of 4.5% due to the incorporation of a nano-scale SiO2 buffer into the MoS2/Si interface. The present device architectures are envisaged as potentially valuable candidates for high-performance photovoltaic devices.

Surface plasmon resonance and field enhancement in #-shaped gold wires metamaterial.

A #-shaped gold wires metamaterial is designed for surface enhanced Raman spectroscopy (SERS) and sensing. The tunability of surface plasmon resonance (SPR) excitations, hotspots distribution, localized field enhancement and sensitivity of the structure are investigated. In contrast to most metamaterial, the #-shaped structure exhibits two pronounced SPRs that are insensitive to the polarization of excitation light. Pure electromagnetic Raman enhancement factors of about 10(6) are achieved on the symmetrically distributed field hotspots. It is possible to break the usable wavelength range of conventional gold SERS substrates via higher order excitations of the #-shaped metamaterial. In addition, the sensitivity and the figure of merits are found to be comparable or even higher than those of conventional SERS substrates. All these factors together with the high reproducibility nature of metamaterial and its simple planer structure suggest that this structure is very promising for surface enhanced spectroscopy and sensing applications.

Extra- and intra-cellular ice formation of red seabream (Pagrus major) embryos at different cooling rates.

The ice crystal formation is assumed as the most lethal factor for the failure of fish embryo cryopreservation and intracellular ice formation (IIF) plays a central role in cell injury during cooling. The objectives were to observe the morphological changes of red seabream (Pagrus major) embryo during the cooling-thawing process, and to examine the effect of cryoprotectant and cooling rate on the temperatures of oil globule ice formation (T(OIF)), extra-cellular ice formation (T(EIF)) and intracellular ice formation (T(IIF)) using cryomicroscope. After thawing, the morphological changes of embryos were observed and recorded by the video attachment and monitor under the microscope. During the cooling process, three representative phenomena were observed: oil globule gradually turned bright firstly, then the whole field of view flashed and the embryo blackened. Cooling rate affect the temperature of both extra- and intra-cellular ice formations. T(EIF) and T(IIF) at high cooling rate were much lower than that at low cooling rate. And the value of T(EIF)-T(IIF) increased from 0.45 to 11.11 degrees C with the increase of cooling rate from 3 to130 degrees C/min. Taken together, our results suggested that high cooling rate with proper cryoprotectant would be a good option for red seabream embryo cryopreservation.

SPP-associated dual left-handed bands and field enhancement in metal-dielectric-metal metamaterial perforated by asymmetric cross hole arrays.

Dual-band left-handed transmissions in the near infrared frequencies through the metal-dielectric-metal metamaterial perforated with an array of asymmetric cross holes are demonstrated. It is shown that the left-handed bands originate from the SPP-associated magnetic response excited by different polarized light and their frequencies can be tuned by the arm's length or width of the cross-gaps. The structures are further optimized at 1.064 microm laser light excitation for elucidating the mechanism and possible application in surface enhanced Raman spectroscopy in sandwiched architectures. This study provides valuable information for the design of compact optical devices with dual left-handed bands in a single structure and may also pave the way toward stable and reproducible substrate design for surface enhanced Raman spectroscopy.

Effect of cryoprotectants on hatching rate of red seabream (Pagrus major) embryos.

The objectives were to investigate the effect of cryoprotectants on the hatching rate of red seabream embryos. Heart-beat embryos were immersed in: five permeable cryoprotectants, dimethyl sulfoxide (DMSO), glycerol (Gly), methanol (MeOH), 1,2-propylene glycol (PG), and ethylene glycol (EG), in concentrations of 5-30% for 10, 30, or 60 min; and two non-permeable cryoprotectants: polyvinylpyrrolidone (PVP), and sucrose (in concentrations of 5-20% for 10 or 30 min). The embryos were then washed and incubated in filtered seawater until hatching occurred. The hatching rate of the embryos treated with permeable cryoprotectants decreased (P<0.05) with increased concentration and duration of exposure. In addition, PG was the least toxic permeable cryoprotectant, followed by DMSO and EG, whereas Gly and MeOH were the most toxic. At a concentration of 15% and 30 min exposure, the hatching rate of the embryos immersed in PG was 93.3+/-7.0% (mean+/-S.D.), however, in DMSO, EG, Gly, and MeOH, it was 82.7+/-10.4, 22.0+/-5.7, 0.0+/-0.0, and 0.0+/-0.0%, respectively. Hatching rate of embryos treated with PVP decreased (P<0.05) with the increase of concentration and exposure time, whereas for embryos treated with sucrose, there was no significant decrease in comparison with the control at the concentrations used.

Chemically assisted handmade enucleation of porcine oocytes.

The purpose of our work was to find an efficient and reliable chemically assisted procedure for enucleation of porcine oocytes connected to the handmade cloning (HMC) technique without the potentially harmful chromatin staining and ultraviolet (UV) irradiation for cytoplast selection. After 41-42 h in vitro maturation, porcine oocytes were incubated with 0.4 microg/mL demecolcine for 45 min. Subsequently, the cumulus cells were removed and zonae pellucidae were partially digested. Oocytes with extrusion cones or oocytes only with polar body (PB) were subjected to oriented bisection. Less than half of the cytoplasm with the extrusion cone or adjacent to the PB was removed with a microblade. The remaining putative cytoplasts, containing the major part of the cytoplasm, were used as recipients for reconstruction with porcine fetal fibroblasts as nuclear donors. The overall efficiency achieved with chemically assisted enucleation was higher compared to oriented bisection without demecolcine incubation (90 +/- 3% vs. 81 +/- 4%, respectively; mean +/- absolute deviation [AD]). Reconstructed and activated embryos were cultured in vitro for 7 days. Fusion, cleavage and blastocyst rates were 87 +/- 7%, 97 +/- 6%, and 28 +/- 9%, respectively. These rates are at least as good as those achieved with normal HMC (81 +/- 4%, 87 +/- 8%, and 21 +/- 9%, respectively). For traditional, micromanipulator-based cloning, fusion and blastocyst rates were similar (81 +/- 10% and 21 +/- 6%, respectively), but the cleavage rate was lower (69 +/- 9%). In conclusion, chemically assisted handmade enucleation seems to be a simpler and potentially superior alternative to more conventional methods used for somatic cell nuclear transfer in pigs.

Model for the effective thermal conductivity of carbon nanotube composites.

We present a novel model of the effective thermal conductivity for carbon nanotube composites by incorporating the interface thermal resistance with an average polarization theory. The dependence of the effective thermal conductivity on nanotube length, diameter, concentration, and interface thermal resistance has been taken care of simultaneously in our treatment. The model predicts that the large length of the carbon nanotubes embedded plays a key role in the thermal conductivity enhancement, while the large interface thermal resistance across the nanotube-matrix interface causes a significant degradation. Interestingly, the model predicts that the nanotube diameter has a very small effect on the thermal conductivity enhancement of the nanotube composites. In addition, the model predicts that the thermal conductivity enhancement of nanotube composites increases rapidly with decreasing the thermal conductivity of the matrix and increases with increasing the thermal conductivity of the carbon nanotube. Predictions from the novel model are in excellent agreement with the experimentally observed values of the effective thermal conductivity of carbon nanotube nanofluids which the classical models have not been able to explain.

[QTL dissection of panicle number per plant and spikelet number per panicle in rice (Oryza sativa L.)].

The genetic mechanism underlying panicle number per plant (PN), spikelet number per panicle (SNP) and its related traits in rice was analysed using 292 F13 RILs from the cross of Lemont/Teqing and a complete linkage map with 272 molecular markers. The RILs showed tremendous transgressive segregation for all traits studied. The weak negative correlation between PN and SNP was observed. Fifty-one QTLs and 45 epistatic QTL pairs affecting these traits were identified, collectively explaining over 60% of the total variation of individual traits. Almost all SNP-QTLs were attributable to one or more of its contributing components. Branching number traits had greater contributions to SNP than length traits, in which the first had twice as many QTLs mapped in the same or near regions with SNP as the latter. Only two PN-QTLs were mapped in the near regions with those of related traits of SNP, suggesting a reasonable recombination between PN and SNP would be available by marker-assisted selection (MAS). Some major QTLs including QPn4 for panicle number, QPbn3a, QPbn3b and QPbl4 for panicle branching and length would be of great value in MAS. It was discussed that a new high-yielding panicle type was resulted from reasonably deploying for QTLs of panicle traits by MAS.

[Introduction of wide spectrum rice bacterial blight resistance gene Xa21 into two-line genic male sterile rice variety Pei'ai 64S].

Agrobacterium-mediated transformation of two-line genic male sterile Indica rice variety Pei'ai 64S was conducted using a cloned gene, Xa21, as the foreign gene and mature embryo calli as the recipients. A total of 46 transgenic plants had been obtained. The PCR analysis and Southern blotting showed the integration of Xa21 gene into the genome the transgenic plants. Results of inoculation with philippine race 6 of Xanthomonas oryzae pv. oryzae indicated that most of transgenic plants obtained high resistance to rice bacterial blight disease (Xoo). Analyses of T1 plants of the tested transgenic lines showed that integrated Xa21 gene could be steadily inherited and segregated in a 3:1 ratio.