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The beneficial effect of supplementing culture medium with melatonin has been reported during in vitro embryo development of species such as mouse, bovine and porcine. However, the effect of melatonin on mouse somatic cell nuclear transfer remains unknown. In this study, we assessed the effects of various concentrations of melatonin (10−6 to 10−12 M) on the in vitro development of mouse somatic cell nuclear transfer embryos for 96 h. Embryos cultured without melatonin were used as control. There was no significant difference in cleavage rates between the groups supplemented with melatonin, dimethyl sulphoxide (DMSO) and the control. The rate of development to blastocyst stage was significantly higher in the group supplemented with 10−12 M melatonin compared with the control group (P < 0.05). Thus, our data demonstrated that adding melatonin to pre-implantation mouse nuclear-transferred embryos can accelerate blastocyst formation.
The presence of piscivorous fish has a significant effect on the structure of fish
assemblages. Exotic, piscivorous largemouth bass (Micropterus salmoides)
have been introduced to a number of Japanese farm ponds that were originally characterized
by a high level of biodiversity. We evaluated the effects of exotic bass on the structure
of the fish assemblage following their introduction into the farm ponds. We collected fish
and measured environmental conditions in 14 ponds of northeastern Japan. The species
richness of pond-dwelling fish assemblages was negatively correlated with the relative
abundance of exotic bass. In addition, the relative abundance of lentic cyprinid species
(e.g., Rhodeus ocellatus ocellatus, Pseudorasbora parva
and Carassius sp.) was negatively correlated with the relative
abundance of exotic bass. The abundance of these species was also influenced by
environmental factors, including transparency and/or coverage of aquatic vegetation,
likely related to their influence on the predatory efficiency of exotic bass. Our results
suggest that the structure of fish assemblages in farm ponds with exotic piscivorous fish
was influenced by both biotic (i.e., predation) and abiotic factors and that some
environmental factors mediate the effects of exotic bass on fish species richness and
Melatonin secreted from the mammalian pineal gland is a free-radical scavenger that protects tissues from cell damage. The present study examined the effects of addition of melatonin to the culture medium on the developmental potential of parthenogenetic and somatic cell nuclear-transferred (SCNT) porcine oocytes. Supplementation of the maturation medium with melatonin did not increase the maturation rate, the proportion of oocytes that cleaved and developed into blastocysts after parthenogenetic activation, or the blastocyst cell number compared to controls. When 10−7 M melatonin was added to the culture medium, the proportion of parthenogenetic oocytes that developed to the 2-cell and 4-cell stages was significantly higher than that of controls. The potential of melatonin-treated oocytes to develop into blastocysts was high but not significantly different from that of controls. The addition of 10−7 M melatonin to the culture medium did not increase the preimplantation development of SCNT oocytes. Melatonin treatment significantly reduced the levels of reactive oxygen species in 4-cell parthenogenetic and SCNT embryos, but did not reduce the proportion of apoptotic cells in parthenogenetic and SCNT blastocysts. Although the results indicated that parthenogenetic and SCNT melatonin -treated embryos had significantly lower levels of reactive oxygen species than controls, the potential of melatonin-treated embryos to develop into blastocysts was not significantly higher than that of controls, in contrast to previous reports. The beneficial effects of melatonin on the developmental potential of oocytes might depend on the culture conditions.
Somatic cell nuclear-transferred (SCNT) oocytes have a high potential for development in vitro, but a large proportion of embryos that are transferred to recipients is aborted before parturition. The precise mechanism for the high abortion rate is unknown, but abnormal placenta formation is frequently observed in SCNT-cloned pregnancies. The present study examined the effects of treating the recipients with cyclosporin A (CsA), an immunoprotectant, on the proportion of fetuses resulting from SCNT-cloned pregnancies. Cloned embryos developed from enucleated oocytes and receiving cumulus cells from F1 (C57BL/6 × DBA, H-2b/d) females were transferred to outbred ICR (in which the H-2 complex was not fixed) recipient females. Each recipient received an intraperitoneal injection of CsA or vehicle. Compared with vehicle, administration of CsA to recipients on day 4.5 of pregnancy significantly increased the proportion of fetuses observed on day 10.5. The proportion of fetuses at day 18.5 of pregnancy in recipients receiving CsA treatment was slightly higher than that in controls. This study is the first to report that CsA administration increases the proportion of fetuses resulting from SCNT-cloned pregnancies.
A protonated form of a layered perovskite was prepared from an Aurivillius phase Bi2SrNaNb3O12via acid treatments, and the effect of the type of mineral acids was investigated. The treatment with HX (X = Cl, Br, I) resulted in the formation of a protonated form H1.8[Sr0.8Bi0.2NaNb3O10], while no reactions were observed for HNO3 and H2SO4 under the present experimental conditions. All the products obtained by HX-treatments exhibited layered structures and the structures of the perovskite-like slabs were preserved.
Improvement of electrical properties by heat treatment with high-pressure H2O vapor was discussed for 7.4×1017cm−3 phosphorus-doped pulsed laser crystallized silicon films. The analysis of the electrical conductivity resulted in that 1.3×106-Pa-H2O vapor annealing at 270°C for 3 h reduced the density of defect states from 5.5 ×1018 cm−3(as crystallized) to 5.0×1017 cm−3 for tail states and from 1.0×1018 cm−3(as crystallized) to 3.0×1017 cm−3 for deep level defect states. The potential barrier height at grain boundaries decreased from 0.34 eV (as crystallized) to 0.05 eV by the heat treatment. The combination of oxygen plasma with high-pressure H2O vapor annealing effectively reduced the densities of defect tail sates as well as deep level defect states. It achieved a high performance of thin film transistors with a threshold voltage of 1.3 V and an effective mobility of 160 cm2/Vs.
Fully radioactive waste glass of HLLW generated in Tokai Reprocessing Plant was produced by using a small Joule-heated ceramic melter at the Chemical Processing Facility (CPF), Tokai Works, PNC, Japan. Static leach tests using the glass were carried out in doubly distilled water for a period of up to three months at 30°C and 90 °C. Gamma spectrometry was performed to measure 134Cs, 137Cs and 60Co in the leachates. After the chemical separation of Cs isotopes in the leachates, it was newly possible to measure 125Sb, 144Ce, 154Eu and 155Eu. Alpha spectrometry was performed to measure 239Pu+240Pu, 241Am and 244Cm in the leachates. Adsorption of the actinides on the wall of the leach vessel was recognized in all cases. Leaching behavior of the measured radionuclides were evaluated by considering mass balance of the radionuclides which were leached.
A considerable range in alteration rates of basaltic glasses in various environments has been reported in previous studies. However, these studies paid only cursory attention to the environmental conditions under which the glass had been altered. In this study, the alteration of basaltic glasses was investigated and the environmental conditions and the alteration rate were discussed. Two sample ages were represented: 280 years and 2800 years. Basaltic glasses and their alteration layers were analyzed by electron probe microanalyzer (EPMA) and the thickness of the alteration layers were measured by scanning electron microscope (SEM). The ground water collected near the sampling point of Zunazawa Scoria and the pore water of both samples were analyzed. The alteration temperature and flow rate of water are estimated to be about 13t and 0.2 1/cm2/y respectively on the basis of meteorological data. The alteration layers of young aged basaltic glasses in freshwater conditions are similar to those of leached borosilicate glasses. The alteration rates of these basaltic glasses are estimated to be several um/1000y. The elemental concentrations in the ground water can be roughly explained as the result of leaching of the glasses.
We report on the synthesis of β-FeSi2 bulk materials using Horizontal Gradient Freeze (HGF) method. Chunk and powder FeSi2 or high-purity Fe (4N) and Si (9N) were used as starting materials. Three values (1:2, 2:5 and 1:3) of the Fe:Si ratio were selected in the very narrow α and β ranges of the equilibrium phase diagram. Samples were melted between 1300°C and 1500°C in high purity graphite crucibles covered with boron nitride. After cooling, the samples were kept at 800°C and 900°C during 66 to 100 hours, leading to transformation from α to β phase. Cooling rate and annealing time were taken as the two main parameters to optimize the growth conditions. Principal structural characterization was made by X-ray diffraction (XRD). Correlation with stoichiometry was achieved using the results of Rutherford Backscattering Spectroscopy (RBS) and Electron Probe X-Ray Micro Analysis (EPXMA). The samples obtained from 1:2 ratio exhibited mainly β phase while the 2:5 ratio specimens revealed almost α phase structure. The samples prepared with 1:3 ratio was found as a mixture of α and β phases under Si-rich conditions.
Metal-induced low temperature (≤ 550 °C) crystallization of a-Si1-xGex (0 ≤ × ≤ 1 ) layers on SiO2 films has been investigated. For low Ge fractions below 20 %, Ge-doping enhanced plane growth was observed. This realized strain-free poly-Si0.8Ge0.2 films with large grains (18 μm). On the other hand, dendrite growth was dominant for intermediate Ge fractions with 40–60 %. Directions and widths of dendrites became straight and narrow with decreasing annealing temperature. As a result, very sharp needlelike crystals (width: 0.05 μm, length: 10 μm) were obtained at the optimized growth conditions (x: 0.4, annealing: 450 °C, 20 h). These new polycrystalline SiGe films on insulators should be used for the advanced system-in-displays and novel one-dimensional wires.
Ion beam stimulated solid phase crystallization of a-Si1-xGex (0 ≤ x ≤ 1) on SiO2 has been investigated. The critical temperature to cause crystal nucleation can be successfully decreased by 150 °C for a-Si1-xGex with all Ge fractions (0 - 100 %) by using ion stimulation. As a result, crystal growth below the softening temperature (∼ 500 °C) of glass substrates was achieved for samples with Ge fractions exceeding 50 %. This method combined with Ge doping and ion stimulation will be a powerful tool to fabricate poly-SiGe TFTs on low cost glass substrates.
We review our capacitor technology using (Ba,Sr)TiO3 (BST) as a capacitor dielectric for dynamic random access memory (DRAM) application. Among a number of issues for BST capacitor process integration in DRAM cells, two important technologies are discussed. As an electrode technology, we propose All PErovskite Capacitor (APEC) technology, in which conducting perovskite oxide of SrRuO3 (SRO) is used as capacitor electrodes. For chemical vapor deposition (CVD) of BST, we propose In-situ Multi-Step (IMS) process, which is a sequential repetition of low temperature deposition of ultra thin BST film and crystallization in the same chamber. By using APEC technology and IMS CVD process of BST, we can simultaneously achieve good electrical characteristics (low leakage current and high permittivity) and good step coverage. The combination of APEC technology and IMS CVD process of BST is a promising BST capacitor process technology for future DRAMs.
The effects of Ge layer insertion on the solid-phase crystallization (SPC) of a-Si on SiO2 have been investigated. Three types of sample structures, i.e., (a) a-Si/a-Ge/a-Si/SiO2, (b) a-Si/a-Ge/SiO2, and (c) SiO2/a-Ge/a-Si/SiO2, were prepared and annealed at 600°C. For the structure (a) with a thin (∼ 5 nm) Ge layer, Ge atoms completely diffused into a-Si, and SPC was not enhanced. On the other hand, for the structure (a) with Ge layers thicker than 10 nm, Ge atoms were localized at the initial position. Such a localization of Ge atoms was remarkable for the structures (b) and (c) even for samples with thin Ge layers. For samples with Ge localization, significant enhancement of SPC of a-Si was observed. These results indicated that crystal nucleation was initiated in the inserted Ge layers, and then propagated into a-Si. The Ge layer insertion can be employed for positioning of crystal nucleation in SPC of a-Si.
We studied X-ray Fourier transform holography using separated holography-mask and sample geometry. The method was successfully applied to the imaging of the magnetic nanostructure using soft X-ray in addition to the cross-sectional imaging of Cu interconnect lines using hard X-ray.
We examined the optimal conditions for somatic cell nuclear transfer (SCNT) in the rat. First, we examined the effect of preincubation time before activation on SCNT rat oocytes produced in the presence of MG132 with regard to spindle formation and the potential to develop into blastocysts. The spindles of SCNT oocytes continued to elongate with an increase in the culture duration and, in approximately half of oocytes, the chromosomes were distributed along the spindles at 120 min after incubation. Such abnormal spindle formation in SCNT oocytes is a possible reason for the low developmental potential of SCNT rat oocytes. To inhibit the formation of abnormal spindle formation, we examined secondly the developmental potential of rat SCNT oocytes that had been preincubated with nocodazole and demecolcine instead of MG132. The developmental rates in SCNT oocytes, however, were decreased. For successful rat somatic cell cloning, two steps might be required: (1) to culture the somatic cell nuclei for a sufficient time in MII oocyte cytoplasm to enhance nuclear reprogramming; and (2) to induce normal spindle formation with normal chromosomal construction.
To facilitate nuclear reprogramming, somatic cells or somatic cell nuclear-transferred (SCNT) oocytes have been treated with the histone deacetylase inhibitor trichostatin A (TSA), or the DNA methyltransferase inhibitor, 5-aza-2′-deoxycytidine (5-aza-dC), to relax epigenetic marks of differentiated somatic cells. TSA-treated SCNT oocytes have increased developmental potential, but the optimal treatment period is unknown. Reduced methylation levels in somatic cells have no positive effect on SCNT oocytes, but the treatment of SCNT embryos with 5-aza-dC has not been investigated. We examined the effect of TSA treatment duration on the developmental potential of mouse SCNT oocytes and the effect of 5-aza-dC treatment on their in vitro and in vivo developmental potential. To determine the effects of TSA treatment duration, nuclear-transferred (NT) oocytes were cultured for 0 to 26 h with 100 nM TSA. SCNT oocytes treated with TSA for 8 to 12 h had the higher rate of development to blastocysts and full-term fetuses were obtained after treatment for 8 to 12 h. When oocytes were treated for 14 h and 26 h, blastocyst rates were significantly decreased and fetuses were not obtained. To examine the effect of 5-aza-dC, 2-cell stage SCNT embryos were cultured with 10 or 100 nM 5-aza-dC for 48 h to the morula stage and transferred. The potential of embryos treated with 5-aza-dC to develop into blastocysts was decreased and no fetuses were obtained after transfer. The findings demonstrated that long-term TSA treatment of SCNT mouse oocytes and treatment with 5-aza-dC inhibit the potential to develop into blastocysts and to fetuses after transfer.
Generally, epiglottic cysts have been treated by the puncture technique or surgical resection. However, these techniques can result in accidental injury to the cyst wall. As a result, the contents of the cyst may spread throughout the larynx, trachea and pharyngeal cavity. The ideal treatment would involve complete resection without cyst perforation. We use a completely different approach for the resection of epiglottic cysts, with successful results, which we term the advanced phono-ultra-microsurgical technique. One difference between this method and previous techniques of surgical epiglottic cyst resection is that the cyst is sealed off before resection in order to prevent rupture and spread of its contents. To enable this, we have developed a special device to facilitate suturing of the vocal fold epithelium, utilising a knot-pusher. This suturing technique allows complete removal of epiglottic cysts. Our technique allows optimal prevention of cyst rupture and spread of contents.
This study aimed to estimate the effectiveness of a full digital, high definition video system for laryngeal observations.
A newly available, full digital, high definition video camera and high definition video monitor were used. With an endoscopic adaptor and rigid telescope, laryngoscopy and stroboscopy were performed on patients with various kinds of laryngeal lesions.
All laryngeal lesions were observed and recorded by the full digital, high definition video camera without incident. The image quality for laryngoscopy and stroboscopy was far superior to that of a conventional video system, including video-endoscopy. Even tiny structures or lesions could clearly be visualised on the monitor. The still image obtained from the full digital, high definition video camera was 1920 × 1080 pixels and was comparable to that obtained from a still camera.
Full digital, high definition video cameras are now commonplace products and can easily be applied to patients with laryngeal disorders. They provide superior laryngeal images, compared with conventional video systems. Furthermore, high definition video systems are cheaper than proprietary medical video systems. We consider our system to represent an accessible technique of gaining superior laryngeal observation in otolaryngological clinics.
We introduce here an easy but effective method for detailed observation of the larynx and hypopharynx. During the endoscopic observation, the patient's head is turned to one side. Anatomical structures on the same side of the endolarynx, such as the laryngeal ventricle and inferior surface of the vocal fold, are easily observed. In addition, observation of the opposite side of the hypopharynx also becomes easier. Such head turning is also useful in patients with an oblique larynx, in whom the epiglottis obstructs insertion of the endoscope. This is a simple but very effective technique for laryngeal and hypopharyngeal observation.