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This study investigated the effect of the flavonoid-based compound isorhamnetin (ISO) on maturation and developmental competence in oxidative stress-exposed porcine oocytes in vitro. Treatment with 2 μM ISO (2 ISO) increases the developmental rate of oxidative stress-exposed porcine oocytes during in vitro maturation (IVM). The glutathione level and mRNA expression of antioxidant-related genes (NFE2L2 and SOD2) were increased in the 2 ISO-treated group, whereas the reactive oxygen species level was decreased. Treatment with 2 ISO increased mRNA expression of a cumulus cell expansion-related gene (SHAS2) and improved chromosomal alignment. mRNA expression of maternal genes (CCNB1, MOS, BMP15 and GDF9) and mitogen activated protein kinase (MAPK) activity were increased in the 2 ISO-treated group. The total cell number per blastocyst and percentage of apoptotic cells were increased and decreased in the 2 ISO-treated group, respectively. Treatment with 2 ISO increased mRNA expression of development-related genes (SOX2, NANOG, and POU5F1) and anti-apoptotic genes (BCL2L1 and BIRC5) and decreased that of pro-apoptotic genes (CASP3 and FAS). These results demonstrate that 2 ISO improves the quality of porcine oocytes by protecting them against oxidative stress during IVM and enhances subsequent embryo development in vitro. Therefore, we propose that ISO is a useful supplement for IVM of porcine oocytes.
Our previous studies have already revealed that β-cryptoxanthin (BCX), hesperetin (HES), and icariin (ICA) antioxidants are effective for in vitro maturation (IVM) of porcine oocytes. In this study, we investigated which of BCX, HES, or ICA was more effective for IVM of porcine oocytes. The antioxidant properties were assessed with aged porcine oocytes and embryos by comparing 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH), reducing power, and H2O2 scavenging activity assays. The chemical assay results demonstrated that BCX had a greater DPPH scavenging activity and reducing power than HES and ICA, compared with controls. However, the H2O2 scavenging activity of the antioxidants was similar when tested at the optimal concentrations of 1 μM BCX (BCX-1), 100 μM HES (HES-100), and 5 μM ICA (ICA-5). The biological assay results showed that BCX-1 treatment was more effective in inducing a significant reduction in reactive oxygen species (ROS), improving glutathione levels, and increasing the expression of antioxidant genes. In addition, BCX-1 inhibited apoptosis by increasing the expression of anti-apoptotic genes and decreasing pro-apoptotic genes in porcine parthenogenetic blastocysts. BCX-1 also significantly increased the blastocyst formation rate compared with the ageing control group, HES-100 and ICA-5. This study demonstrates that damage from ROS produced during oocyte ageing can be prevented by supplementing antioxidants into the IVM medium, and BCX may be a potential candidate to improve assisted reproductive technologies.
Two challenges exist in laser-assisted atom probe tomography (APT). First, a drastic decline in mass-resolving power is caused, not only by laser-induced thermal effects on the APT tips of bulk oxide materials, but also the associated asymmetric evaporation behavior; second, the field evaporation mechanisms of bulk oxide tips under laser illumination are still unclear due to the complex relations between laser pulse and oxide materials. In this study, both phenomena were investigated by depositing Ni- and Co-capping layers onto the bulk LaAlO3 tips, and using stepwise APT analysis with transmission electron microscopy (TEM) observation of the tip shapes. By employing the metallic capping, the heating at the surface of the oxide tips during APT analysis became more symmetrical, thereby enabling a high mass-resolving power in the mass spectrum. In addition, the stepwise microscopy technique visualized tip shape evolution during APT analysis, thereby accounting for evaporation sequences at the tip surface. The combination of “capping” and “stepwise APT with TEM,” is applicable to any nonconductors; it provides a direct observation of tip shape evolution, allows determination of the field evaporation strength of oxides, and facilitates understanding of the effects of ultrafast laser illumination on an oxide tip.
We present a rapid and sensitive surface acoustic wave (SAW) immunosensor that utilizes gold staining as a signal enhancement method. A sandwich immunoassay was performed on sensing area of the SAW sensor, which could specifically capture and detect cardiac markers (cardiac troponin I (cTnI), creatine kinase (CK)-MB, and myoglobin). The analytes in human serum were captured on gold nanoparticles (AuNPs) that were conjugated in advance with detection antibodies. Introduction of these complexes to the capture antibody-immobilized sensor surface resulted in a classic AuNP-based sandwich immunoassay format that has been used for signal amplification. In order to achieve further signal enhancement, a gold staining method was performed, which demonstrated that it is possible to obtain gold staining-mediated signal augmentation on a mass-sensitive device. The sensor response due to gold staining varied as a function of cardiac marker concentration.
We present a versatile and facile route for highly sensitive detection of
analytes through coupling the enlargement of gold nanoparticles (Au NPs)
with fluorescence decrease. The fluorescence intensity of dye molecules
(e.g., fluorescein or rhodamine B) significantly decreased with the
increasing concentration of reducing agents, such as hydrogen peroxide and
hydroquinone. The sensitivity for the detection of reducing agents was much
higher than other detection methods based on the absorbance measurement of
enlarged gold nanoparticles or quantum dot-enzyme hybridization. We could
successfully detect acetylthiocholine with the detection limit of several nM
orders, using an enzymatic reaction by acetylcholinesterase, a key route for
the detection of toxic organophosphate compounds. The fluorescence
decreasing approach described in this work requires only a simple addition
of fluorescence dye to the reaction solution without any chemical
modification. The strategy of fluorescence decrease coupled with
nanoparticle growth will be applied on the fluorescent substrate to develop
detection templates for highly sensitive optical biosensor.
Electron tomography and high-resolution transmission electron microscopy were used to characterize the unique 3-dimensional (3D) structures of twinned Zn3P2 (tetragonal) and InAs (zinc blende) nanowires synthesized by the vapor transport method. The Zn3P2 nanowires adopt a unique superlattice structure that consists of twinned octahedral slice segments having alternating orientations along the axial  direction of a pseudocubic unit cell. The apices of the octahedral slice segment are indexed as six equivalent <112> directions at the  zone axis. At each 30 degrees turn, the straight and zigzagged morphologies appear repeatedly at the <112> and <011> zone axes, respectively. The 3D structure of the twinned Zn3P2 nanowires is virtually the same as that of the twinned InAs nanowires. In addition, we analyzed the 3D structure of zigzagged CdO (rock salt) nanowires and found that they include hexahedral segments, whose six apices are matched to the <011> directions, linked along the  axial direction. We also analyzed the unique 3D structure of rutile TiO2 (tetragonal) nanobelts; at each 90 degree turn, the straight morphology appears repeatedly, while the in-between twisted form appears at the  zone axis. We suggest that the TiO2 nanobelts consist of twinned octahedral slices whose six apices are indexed by the <011>/<001> directions with the axial  direction.
Metal organic deposition (MOD) is one of the attractive processes for coated conductor applications because it is a non-vacuum cost-effective process. Many research groups have successfully fabricated high-JC YBCO coated conductor on the RABiTS and IBAD-YSZ or GZO template with the MOD process. Reports on MOD-processed YBCO coated conductors prepared on the IBAD-MgO template, however, are hardly found. The precursor solution was coated on the CeO2 capped IBAD-MgO template using the slot-die coating method, calcined at a temperature of 550oC, and fired at high temperatures for 2 h 30 min in a reduced oxygen atmosphere. Optimal processing resulted in YBCO coated conductors exhibiting JC value of 0.75 MA/cm2 at 77 K in self-field. The JC values of YBCO coated conductors were found very sensitive to their microstructure, critical temperature, and in-plane texture.
Residual ion implantation damage at source/drain junctions of excimer laser annealed polycrystalline silicon (poly-Si) thin film transistor (TFT) was investigated by high-resolution transmission electron microscopy (HR-TEM). Cross-sectional TEM observation showed that XeCl excimer laser (λ=308 nm) energy decreased considerably at the source/drain junctions of top-gated poly-Si TFT due to laser beam diffraction at the gate electrode edges and that the silicon layer amorphized by ion implantation, was not completely annealed at the juncions. The HR-TEM observation showed severe lattice disorder at the junctions of poly-Si TFT.
A new self-aligned poly-Si TFT has been fabricated by employing a photoresist backside exposure technique. A pre-patterned aluminum (Al) layer on a-Si film not only induces the lateral grain growth (∼1.6 μm) in excimer laser crystallization but also implements the selfalignment of the gate region with the lateral grain region. Photoresist backside exposure through poly-Si film has been successfully performed because crystallized poly-Si has a fairly high UV transmittance. A self-aligned poly-Si TFT with a single grain boundary within the 2 μm channel was successfully fabricated and high on/off current ratio (∼107) was obtained.
The electrical and mechanical properties in indium-tin-oxide films deposited on polymer substrate were examined. The materials of substrates are polyethersulfone(PES), polycarbonate(PC), polyethylene terephthalate(PET) which have gas barrier layer and anti-glare coating for plastic-based devices. The experiments were performed by rf-magnetron sputtering using a special instrument and buffer layers. Therefore, we obtained a very flat polymer substrate deposited ITO film and investigated the effects of buffer layers, in addition to the instrument. Moreover, the influences of an oxygen partial pressure and post-deposition annealing in ITO films deposited on polymer substrates were clarified. X-ray diffraction observation, measurement of electrical property, and optical microscope observation were performed for the investigation of micro-structure and electro-mechanical properties. They indicated that as-deposited ITO thin films are amorphous and become quasi-crystalline after adjustment of oxygen partial pressure and thermal annealing above 180 °C. As the results, we obtained 20-25 Ω/ of ITO films with a good transmittance (above 80%) under 0.2 % oxygen contents and vacuum annealing. Furthermore, using organic buffer layer, we obtained ITO films which have rather high electrical resistance (40-45 Ω/ ) but have improved optical (more than 85%) and mechanical characteristics compared to the counterparts.
In this study, the quality of thin film diode (TFD) as a switching device for active-matrix liquid-crystal-displays (AM-LCDs) was enhanced by low temperature annealing conditions with high reliability and good electrical properties. Device was composed with Ta as bottom electrode, anodic Ta2O5 as insulator layer and top electrode. Two types of material such as Ti and Cr were evaluated as a top electrode of the TFD device to optimize the symmetry of current-voltage characteristic curve, respectively. The annealing was done at low temperature conditions below 350°C. The low temperature annealing improved the TFD device with nearly perfect symmetry under high electric field.
In this paper, we show that the absolute value of the signature of the 2-parallel version of a link is less than or equal to the nullity of it and show that the signature, nullity, and Minkowski units of the 2-parallel version of a certain class of links are always equal to 0, 2, and 1 respectively.
We have proposed and fabricated a new poly-Si TFT that employs selectively doped regions between the source and drain in order to reduce leakage current without the sacrifice of the on current. In the proposed poly-Si TFTs, the selectively doped regions where doping concentration is identical to that of source/drain, reduce the effective channel length during the on state. Under the off state, the selectively doped regions may reduce the lateral electric field induced in the depletion region near drain so that the leakage current reduces considerably. The experimental data of the proposed TFT shows that it has the high on-current, low leakage current and low threshold voltage when compared with conventional TFT. The fabrication steps for the proposed TFT are reduced because ion-implantation for source/drain and selectively doped regions is performed simultaneously prior to an excimer laser irradiation. It should be noted that, in the proposed TFT, only one excimer laser annealing is required while two excimer laser annealing steps are required in conventional TFT.
We propose new poly-Si TFT's with selectively doped region in the center of channel in order to reduce large leakage current. In proposed TFT's, the selectively doped region redistributes total induced electric field in the channel. For VGS<0, VDS> 0 in the n-channel proposed TFT's, most of the high electric field applies in the depletion regions which exist the drain/undoped region and undoped region/selectively doped region which faces to the source. Comparing with conventional TFT's, the electric field induced near the drain junction reduces to about 1/2, therefore, electron-hole pairs generated in drain junction are considerably reduced. Furthermore, the ON-current of proposed TFT's is the same or slightly lower than that of conventional ones. Consequently, the experimental data show the considerable improvement of the ON/OFF current ratio.
A novel method to control the recrystallization depth of amorphous silicon (a-Si) film during the excimer laser annealing (ELA) is proposed in order to preserve a-Si that is useful for fabrication of poly-Si TFT with a-Si offset in the channel. A XeCl excimer laser beam is irradiated on a triple film structure of a-Si thin native silicon oxide (~20Å)/thick a-Si layer. Only the upper a-Si film is recrystallized by the laser beam irradiation, whereas the lower thick a-Si film remains amorphous because the thin native silicon oxide layer stops the grain growth of the poly-crystalline silicon (poly-Si). So that the thin oxide film sharply divides the upper poly-Si from the lower a-Si.
Excimer laser annealing method employing artificial nucleation seed is proposed to increase the grain size of polycrystalline silicon(poly-Si). We utilize Si component incorporated in aluminum(Al)-sputtering source for the nucleation seed. Si clusters which are to be used as nucleation seed are successfully formed on the substrate by deposition and etch-back of Si-incorporated Al layer. Irradiation of excimer laser on amorphous silicon(a-Si) film deposited on the substrate prepared by our method results in enlargement of poly-Si grains, compared with conventional laser recrystallization. Poly-Si thin film transistor also shows much improved electrical perfbrmance which directly reflects the quality of poly-Si film recrystallized by our method.
The new laser annealing technique to control the surface morphology and microstructure of poly-Si film is proposed. Compared with the conventional laser annealing technique where the laser beam is irradiated on the whole area of active layer, our new method make the laser beam transmitted locally onto the active amorphous silicon (a-Si) layer. Using the masking window in grid shape, the active layer is recrystallized in the lattice shape during the laser irradiation. By the optical microscope and scanning electron microscopy (SEM), we observed the orderly pattern, which consists of amorphous and poly-Si regions. In our new poly-Si film, the rough surface morphology, which is shown in conventional sample, could not be found. Furthermore we fabricated a poly-Si TFT utilizing the active poly-Si film recrystallized by our new method. The new poly-Si TFT showed much higher ON current than the conventional poly-Si TFT, although the leakage current is relatively high. The excellent ON characteristics may be attributed to the uniform surface morphology. After hydrogenation, the electrical characteristics of our new polySi TFT was improved considerably and this device may be applied successfully to the active matrix liquid crystal displays (AMLCD's).
There have been many reports on the low temperature crystallization of amorphous silicon films by introducing a trace amount of metal impurity for low temperature poly-Si TFTs applications. MIC (Metal Induced Crystallization) uses various metals, to lower crystallization temperature. In this study, a new crystallization method called FALC (Field Aided Lateral Crystallization) in which an electric field is applied during the crystallization was explored. Among possible alloying elements with Si, Ni and Al were selected to compare the effects of these impurities on the FALC.
A trace of Ni lowered the crystallization temperature of a-Si down to 5001C and induced lateral crystal growth along the electric field into the metal free region. But Al exhibited no such effect. A new crystallization method, FALC, showed considerably enhanced speed of lateral crystallization and a strong preferred orientation in crystallized Si-films.
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