添加剂对石膏创花板性能的影响   总被引：1，自引：0，他引：1  

邓玉和  古野毅 《林产工业》1998,(2)

研究表明：在石膏刨花板生产中,添加０．５％～１％的缓凝剂－硼砂可延长石膏的初凝而对板的物理力学性能不产生明显影响,相反对其静曲强度和弹性模量等有一定的改进;添加５％～１５％的水泥对板的物理力学性能均有所改进,特别是吸水厚度膨胀率;水泥用量１０％时,对板的性能改进最明显;水泥和硼砂同时使用无不良影响。  相似文献   

Properties of curved laminated veneer lumber made from fast-growing species with radiofrequency heating for use in furniture     

Zhi-Hui Wu  Takeshi Furuno  Bin-Yuan Zhang 《Journal of Wood Science》1998,44(4):275-281

Curved laminated veneer lumber (LVL) is manufactured from glue-coated pieces of rotary-cut veneers assembled and pressed between molds. In this study, curved LVLs were produced from two fast-growing wood species such as massion pine (Pinus massoniana Lamb.) and poplar (Populus euramericana CV. I.) for use in furniture. In addition to the applicability of the two wood species used, the optimum technological conditions of curved LVL production with radiofrequency (RF) heating and the physical and mechanical properties of curved LVL were investigated. The results are as follows: (1) Curved LVL made from massion pine and fast-growing poplar shows excellent mechanical properties. These fast-growing wood species are suitable for curved LVL being used as furniture structural members. (2) The mechanical properties of curved LVL are affected by frequency, voltage, RF application time, and moisture content, with the RF application time and moisture content having more important effects on the mechanical properties than the frequency and the voltage. (3) The mechanical properties of curved LVL increase with a linear increase in the density of curved LVL.The abstract of this study was presented at the 9th Annual Meeting of the Chugoku Shikoku Branch of the Japan Wood Research Society, Tottori, October 4, 1997  相似文献   

Voltage-dependent modulation of the neuronal nicotinic acetylcholine receptor-channel by cartap     

Keiichi Nagata  Tomoko Ikeda  Toshio Shono 《Pest management science》1999,55(4):452-456

Nicotinic acetylcholine receptor-channels (AChR) are believed to be the target site of cartap. In order to clarify the mechanisms of the cartap interaction with nicotinic AChRs, single-channel patch clamp experiments were performed using rat clonal phaeochromocytoma (PC12) cells. Cartap increased the short closures occurring during single-channel openings induced by acetylcholine (ACh). Thus, when co-applied with acetylcholine, cartap markedly shortened the open time associated with bursts. These effects were voltage-dependent, being more prominent at negative voltages. These results strongly suggest that cartap acts as an open channel blocker at the neuronal nicotinic AChR. © 1999 Society of Chemical Industry  相似文献   

Interactions of picrodendrins and related terpenoids with ionotropic GABA receptors of mammals and insects     

Yoshihisa Ozoe  Miki Akamatsu  Taizo Higata  Izumi Ikeda  Kazuo Mochida  Kazuo Koike  Taichi Ohmoto  Tamotsu Nikaido 《Pest management science》1999,55(6):665-666

Different structural features govern the interaction of picrodendrins and related terpenoids with rat and with housefly GABA receptors. This supports previous studies which suggest that there are significant differences between the structures of the binding sites in these two receptors.  相似文献   

Survey of tumorigenic sensitivity in 6-month rasH2-Tg mice studies compared with 2-year rodent assays     

Shigeru Hisada  Kenjiro Tsubota  Kenji Inoue  Hisaharu Yamada  Takanori Ikeda  Frank D. Sistare 《Journal of toxicologic pathology》2022,35(1):53

The pharmacokinetic endpoint of a 25-fold increase in human exposure is one of the specified criteria for high-dose selection for 2-year carcinogenicity studies in rodents according to ICH S1C(R2). However, this criterion is not universally accepted for 6-month carcinogenicity tests in rasH2-Tg mice. To evaluate an appropriate multiple for rasH2-Tg mice, we evaluated data for 53 compounds across five categories of rasH2-Tg mouse-positive [(1) genotoxic and (2) non-genotoxic] carcinogens and rasH2-Tg mouse-negative [(3) non-genotoxic carcinogens with clear or uncertain human relevance; (4) non-genotoxic rodent-specific carcinogens; and (5) non-carcinogens], and surveyed their tumorigenic activities and high doses in rasH2-Tg mice and 2-year rodent models. Our survey indicated that area under the curve (AUC) margins (AMs) or body surface area-adjusted dose ratios (DRs) of tumorigenesis in rasH2-Tg mice to the maximum recommended human dose (MRHD) were 0.05- to 5.2-fold in 6 category (1) compounds with small differences between models and 0.2- to 47-fold in 7 category (2) including three 2-year rat study-negative compounds. Among all 53 compounds, including 40 compounds of the rasH2-Tg mouse-negative category (3), (4), and (5), no histopathologic risk factors for rodent neoplasia were induced only at doses above 50-fold AM or DR in rasH2-Tg mice except for two compounds, which induced hyperplasia and had no relationship with the tumors observed in the rasH2-Tg mouse or 2-year rodent studies. From the results of these surveys, we confirmed that exceeding a high dose level of 50-fold AM in rasH2-Tg mouse carcinogenicity studies does not appear to be of value.  相似文献   

Application of energy-filtering electron microscopy (EFEM) for analysis of hydrogen peroxide and lignin in epidermal walls of cucumber leaves triggered by acibenzolar-S-methyl treatment prior to inoculation with Colletotrichum orbiculare     

P. Park  T. Kurihara  M. Nita  K. Ikeda  K. Inoue  H. Ishii 《Plant pathology》2019,68(9):1624-1634

Hydrogen peroxide (H₂O₂) and lignin induced by acibenzolar-S-methyl (ASM) during the expression of systemic acquired resistance (SAR) of cucumber plants against the fungus Colletotrichum orbiculare was analysed with electron microscopy and energy-filtering electron microscopy (EFEM). ASM pretreatment consistently led to the blockage of appressorial penetration pegs into leaves at early stages after inoculation, whereas the fungus was able to grow into the vascular tissue after distilled water pretreatment. The blocked pegs, seen frequently at epidermal pectin layers in leaves of ASM-treated plants, were surrounded by abundant electron-dense amorphous material and dots. These were identified as lignin, based on their appearance and high reactivity with KMnO₄. Lignin first appeared as an amorphous material at pectin layers, and then as dots in some areas of the material. The results showed that ASM caused SAR in leaves via faster formation of lignin within 1 day after inoculation. After CeCl₃ treatment to detect H₂O₂, H₂O₂-reactive products (cerium perhydroxides) were seen near ASM-induced lignin formation sites in pectin layers. EFEM analysis showed that Ce and O were located at the same sites as the lignin dots, suggesting that lignin was associated with sources of H₂O₂ generation. The results indicate that the faster H₂O₂ generation and lignification induced by ASM were the potential causes of SAR.  相似文献   

Optimum dietary taurine level in casein-based diet for juvenile red sea bream Pagrus major     

Hiroyuki Matsunari  Takeshi Yamamoto  Shin-Kwon Kim  Takanobu Goto  Toshio Takeuchi 《Fisheries Science》2008,74(2):347-353

ABSTRACT:   This study was conducted to investigate the effect of dietary taurine and cholyltaurine (C-tau) on growth and body composition of juvenile red sea bream Pagrus major . Semi-purified casein-based diets supplemented with 0 (control diet), 0.1, 0.3, 0.5 and 0.7% taurine and 0.5% C-tau were fed to red sea bream (average body weight 4.7 g) for 6 weeks at 20°C. The growth and feed efficiency were the lowest in fish fed the control diet. Taurine supplementation improved the growth and feed efficiency of fish dose-dependently, and the taurine requirement was estimated as 0.52% in terms of optimizing growth and 0.48% in terms of optimizing feed efficiency. Taurine content in the whole body and liver increased with the dietary taurine level. Supplemental C-tau at the 0.5% level had limited effects on the growth and no effect on body taurine, biliary bile salt and liver fat contents. From these results it can be inferred that the optimal dietary taurine requirement of juvenile red sea bream is 0.5% on a dry weight basis, and that the supplementation of taurine in the diet not only improves the growth but also increases hepatic lipid levels of red sea bream juveniles.  相似文献   

Stomach contents of an Indo-Pacific bottlenose dolphin stranded in Amakusa,western Kyushu,Japan     

Takeshi Yamazaki  Sen -Ichi Oda  Miki Shirakihara 《Fisheries Science》2008,74(5):1195-1197

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Characterization and expression of Saprospira cytoplasmic fibril protein (SCFP) gene from algicidal Saprospira spp. strains     

Takeshi Yoshikawa  Miyuki Nakahara  Ayano Tabata  Shingo Kokumai  Go Furusawa  Taizo Sakata 《Fisheries Science》2008,74(5):1109-1117

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Quality prediction of Japanese green tea using pyrolyzer coupled GC/MS based metabolic fingerprinting     

Pongsuwan W  Bamba T  Yonetani T  Kobayashi A  Fukusaki E 《Journal of agricultural and food chemistry》2008,56(3):744-750

A couple between pyrolyzer and gas chromatography/mass spectrometry (GC/MS) has allowed a fast, simple, and low-cost approach to evaluate a quality of Japanese green tea without any sample preparation or derivatization techniques. Using our method, errors from sample preparation could be avoided since raw samples were directly extracted through the extreme heat of the pyrolyzer. In addition, undesired reactions from expensive derivatizing agents, which are commonly needed to treat the samples before analyzing with GC/MS, could be omitted. In order to illustrate the efficiency of this technique, a set of green tea samples from the Tea contest in 2005 in the Kansai area were used. Projection to latent structure by means of partial least squares (PLS) along with orthogonal signal correction (OSC) was selected to explain the relation between green tea's metabolite profiling and its quality. The quality of the model was validated by testing and comparing the predictive ability to the respective model.  相似文献