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81.
K. Itatani K. Koizumi F. S. Howell A. Kishioka M. Kinoshita 《Journal of Materials Science》1989,24(7):2603-2609
The agglomeration process of MgO powder derived from Mg (OH)2 was investigated at fixed temperatures of 600, 800, 900 and 1200° C; these temperatures were chosen as representative of four regions, i.e. below 600° C, 650 to 850° C, 850 to 1050°C and 1050 to 1200° C previously reported. At 600° C, coherent crystallites coalesced within the heating time of 60 min; on further heating till 300 min, the primary particles which consisted of crystallites grew rapidly. The original Mg (OH)2 framework or pseudomorphs, composed of minute crystallites and primary particles, still remained in the powder. At 800° C, the pseudomorphs had disintegrated into fragments. The crystallite growth and primary particle growth were accelerated with increasing the heating times beyond 60 min. At 900° C, a further fragmentation of agglomerates occurred with increasing the heating times; the crystallite and primary particle growth in fragments brought about the pore coalescence. At 1200° C, the crystallite and primary particle growth proceeded with the coarsening of pores; on heating beyond 240 min, the crystallites and primary particles grew rapidly due to the entrapment of pores within them. 相似文献
82.
Masashi Takahashi Shin-Ichi Goto Kazuhisa Mori Izumi Mataga 《Frontiers of Materials Science in China》2008,2(4):437-440
The purpose of this study is to clarify the difference of histology and elemental composition of the cervical enamels among
the human permanent teeth. The reground surfaces at the cervical enamels of them were observed under scanning electron microscopy
(SEM). The contents of seven elements were analyzed quantitatively with electron probe microanalyzer (EPMA). The widths of
the rod sections at the cervical enamels were larger than those at the cuspal enamels. The rod sections at the mesial cervical
enamels in the incisors were more obscure and more decayed by acid solution than those in the premolars and molars. The calcium
and phosphorus contents of the cervical enamels were significantly lower than those of the cuspal enamels. The carbon content
of the cervical enamels was significantly higher than that of the cuspal enamels. The calcium and phosphorus contents of the
cervical enamels were the significantly highest in the premolars. The carbon and sodium contents of the cervical enamels were
significantly highest in the premolars. It is thought that the calcification level is lower, while the content of organic
matter is higher at the cervical enamels than those at the cuspal enamels. It is considered that the sodium causes high calcification. 相似文献
83.
The effect of voluntary exercise on maximal oxygen uptake (VO2 max) was studied in young female Fischer 344 rats. After 10 weeks of wheel-running training, the absolute VO2 max and VO2 max relative to body mass increased without a decline in body mass. The running speed eliciting VO2 max, heart and soleus muscle mass, and succinate dehydrogenase (SDH) activity in the soleus muscle also increased. These results suggest that voluntary exercise is an effective means of increasing the aerobic exercise capacity of young female Fischer 344 rats. 相似文献
84.
We have developed a technology for a robot that uses an indoor navigation system based on visual methods to provide the required
autonomy. For robots to run autonomously, it is extremely important that they are able to recognize the surrounding environment
and their current location. Because it was not necessary to use plural external world sensors, we built a navigation system
in our test environment that reduced the burden of information processing mainly by using sight information from a monocular
camera. In addition, we used only natural landmarks such as walls, because we assumed that the environment was a human one.
In this article we discuss and explain two modules: a self-position recognition system and an obstacle recognition system.
In both systems, the recognition is based on image processing of the sight information provided by the robot’s camera. In
addition, in order to provide autonomy for the robot, we use an encoder and information from a two-dimensional space map given
beforehand. Here, we explain the navigation system that integrates these two modules. We applied this system to a robot in
an indoor environment and evaluated its performance, and in a discussion of our experimental results we consider the resulting
problems. 相似文献
85.
[This corrects the article on p. 1930 in vol. 11, PMID: 20480050.]. 相似文献
86.
Yamamoto T Mukai K Yamashita H Kubota M Fukuda S Kurimoto M Tsujisaka Y 《Journal of Bioscience and Bioengineering》2005,100(2):212-215
Random mutation by error-prone PCR was introduced into kojibiose phosphorylase from Thermoanaerobacter brockii ATCC35047. One thermostable mutant enzyme, D513N, was isolated. The D513N mutant enzyme showed an optimum temperature of 67.5-70 degrees C (the wild type, 65 degrees C), and thermostability up to 67.5 degrees C (the wild type, up to 60 degrees C). The half-lives of D513N were estimated to be 135 h at 60 degrees C, 110 min at 70 degrees C and 6 min at 75 degrees C, respectively. They were about 1.6-fold, 7-fold and 6-fold longer than those of the wild-type enzyme, respectively. 相似文献
87.
Fujita J Yamane Y Fukuda H Kizaki Y Wakabayashi S Shigeta S Suzuki O Ono K 《Journal of Bioscience and Bioengineering》2003,95(4):348-353
We identified three types of acid phosphatase (ACP-I, ACP-II, and ACP-III) produced by Aspergillus oryzae in a submerged culture using only phytic acid as the phosphorous substrate. The optimum pH for the activities of the three enzymes was in the range of 4.5 to 5.5. Analysis of the substrate specificities of these enzymes revealed that ACP-I and ACP-III were acid phosphatases, and ACP-II was a phytase. These enzymes were produced during different periods of mycelial growth: ACP-II was produced during the early phase of cultivation (around 24 h), and ACP-I was produced between 24 to 72 h. ACP-III was detected after the production of ACP-I and ACP-II had ceased. The release of phosphate from phytic acid was expected to be due to the cooperative hydrolysis of these enzymes. 相似文献
88.
Sugimoto K Nomura K Nishimura T Kiso T Sugimoto K Kuriki T 《Journal of Bioscience and Bioengineering》2005,99(3):272-276
Alpha-arbutin is a tyrosinase inhibitor. We synthesized alpha-arbutin-alpha-glycosides by the transglycosylation reaction of cyclomaltodextrin glucanotransferase from Bacillus macerans using alpha-arbutin and starch as acceptor and donor molecules, respectively. We isolated and characterized two major products from the reaction mixture. The structural analyses using 13C- and 1H-NMR spectroscopy proved that they were 4-hydroxyphenyl alpha-maltoside (alpha-Ab-alpha-G1) and 4-hydroxyphenyl alpha-maltotrioside (alpha-Ab-alpha-G2). Both alpha-Ab-alpha-G1 and alpha-Ab-alpha-G2 exhibited competitive-type inhibition on human tyrosinase as alpha-arbutin does. Their K(i) values were calculated to be 0.6 mM and 2.8 mM, respectively, which is slightly and significantly higher than that of alpha-arbutin (0.2 mM). 相似文献
89.
Ayaka Koma Shunichi Asai Chikashi Minemura Sachi Oshima Takashi Kinoshita Naoko Kikkawa Keiichi Koshizuka Shogo Moriya Atsushi Kasamatsu Toyoyuki Hanazawa Katsuhiro Uzawa Naohiko Seki 《International journal of molecular sciences》2021,22(18)
We newly generated an RNA-sequencing-based microRNA (miRNA) expression signature of head and neck squamous cell carcinoma (HNSCC). Analysis of the signature revealed that both strands of some miRNAs, including miR-139-5p (the guide strand) and miR-139-3p (the passenger strand) of miR-139, were downregulated in HNSCC tissues. Analysis of The Cancer Genome Atlas confirmed the low expression levels of miR-139 in HNSCC. Ectopic expression of these miRNAs attenuated the characteristics of cancer cell aggressiveness (e.g., cell proliferation, migration, and invasion). Our in silico analyses revealed a total of 28 putative targets regulated by pre-miR-139 (miR-139-5p and miR-139-3p) in HNSCC cells. Of these, the GNA12 (guanine nucleotide-binding protein subunit alpha-12) and OLR1 (oxidized low-density lipoprotein receptor 1) expression levels were identified as independent factors that predicted patient survival according to multivariate Cox regression analyses (p = 0.0018 and p = 0.0104, respectively). Direct regulation of GNA12 and OLR1 by miR-139-3p in HNSCC cells was confirmed through luciferase reporter assays. Moreover, overexpression of GNA12 and OLR1 was detected in clinical specimens of HNSCC through immunostaining. The involvement of miR-139-3p (the passenger strand) in the oncogenesis of HNSCC is a new concept in cancer biology. Our miRNA-based strategy will increase knowledge on the molecular pathogenesis of HNSCC. 相似文献
90.
A. Maeda K. Kinoshita Y. Inoue H. Kitano T. Nishizaki T. Sato K. Shibata N. Kobayashi 《Journal of Low Temperature Physics》2003,131(5-6):969-973
We investigated the microwave surface impedance in Zn doped YBa2Cu3O
y
. For low Zn concentrations, crossover frequency
p
and viscosity of vortex do not change significantly (at maximum, factor of 2). This is in sharp contrast to the dramatic change in the zero-field quasiparticle scattering time. The robust nature of viscosity on the impurity doping suggests that the quasiparticle scattering time in the vortex core is determined by a different mechanism from that outside the core. 相似文献