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311.
Shinobu Honzawa Naoyuki Takahashi Takayuki Sugiura Midori A. Arai Shigeaki Kato 《Tetrahedron》2009,65(34):7135-7145
Vitamin D3 analogues have been developed for a mutant vitamin D receptor (VDR), Arg274Leu. The mutant VDR has a mutation at Arg274, which forms an important hydrogen bond with 1α-OH of 1α,25-dihydroxyvitamin D3 to anchor the ligand tightly in the VDR ligand binding pocket. Stereoselective synthesis of the A-ring part of the novel vitamin D analogue, 2α-(3-hydroxypropyl)-1α-methyl-25-hydroxyvitamin D3 (4), from d-galactose was accomplished with the key steps of the introduction of the methyl and allyl groups to the chiral building blocks. The new analogue 4 is ca. 7.3-fold more active than the natural hormone 1α,25-dihydroxyvitamin D3 (1). 相似文献
312.
The present Letter considers amplitude death in a pair of oscillators coupled by a time-varying delay connection. A linear stability analysis is used to derive the boundary curves for amplitude death in a connection parameters space. The delay time can be arbitrarily long for certain amplitude of delay variation and coupling strength. A simple systematic procedure for designing such variation and strength is provided. The theoretical results are verified by a numerical simulation. 相似文献
313.
Masakazu Nakamura Hirokazu Ohguri Naoyuki Goto Hiroshi Tomii Mingsheng Xu Takashi Miyamoto Ryousuke Matsubara Noboru Ohashi Masaaki Sakai Kazuhiro Kudo 《Applied Physics A: Materials Science & Processing》2009,95(1):73-80
Extrinsic factors to disturb the carrier transport in pentacene field-effect transistors (FETs), as a representative of the
high-mobility organic FETs (OFETs), have been comprehensively analyzed by using atomic-force-microscope potentiometry (AFMP),
microscopic four-point-probe field-effect transistor (MFPP-FET) measurement, and other techniques. In the first part, by mainly
using AFMP as a powerful tool to reveal the potential distribution in working OFETs, we show how and how much the formation
of source/drain electrodes influences the apparent field-effect mobility both for top- and bottom-contact configurations.
In the second part, we show the influence of irregular grain structures and regular grain boundaries. The films grown both
at very low and high temperature ranges contain distinctive insulating parts, which make the apparent mobility very low. Within
the moderate growth temperature range, the intrinsic field-effect mobility obtained by MFPP-FET measurement is proportional
to the average grain size. This behavior is well explained by the polycrystalline model with the diffusion theory. According
to the observations in this work, it is obvious that these extrinsic limiting factors must be carefully excluded to discuss
the intrinsic mechanism of the carrier transport in OFETs. 相似文献
314.
Sasaki Y Miyamoto T Hidaka Y Satoh H Takuma N Sengoku K Sugimori H Inaoka T Aburano T 《Magnetic resonance imaging》2006,24(2):201-203
A 24-year-old woman (Gravida I, Para I) at estimated 32 weeks of pregnancy was referred to our department for evaluation of a suspected fetal gastroschisis. Ultrasound scan revealed multiple loops of dilated bowel outside the fetal abdomen and absence of membrane surrounding the herniated loops of the intestines. Three-dimensional (3D) magnetic resonance imaging was performed to obtain more information on the bowel both outside and inside the abdomen. Images were constructed with T1-weighted fat-suppressed 3D fast low-angle shot sequences using a maximum intensity projection algorithm. The 3D images made possible the realization of fetal bowel conditions with greater definition and accuracy. 相似文献
315.
316.
Takagi N 《The Journal of the Acoustical Society of America》2002,111(6):2887-2896
Eight monolingual Japanese listeners were trained to identify English /r/ and /l/ by using 560 training tokens produced by ten talkers in three positions (200 word initial, 200 consonant cluster, and 160 intervocalic tokens). Their baseline performance and transfer of learning were measured using 200 word initial and 200 consonant cluster tokens produced by additional ten talkers. Long-term training (15 days) with feedback indeed increased sensitivity to the nontraining tokens, but tremendous individual differences were found in terms of initial and final sensitivity and response bias. Even after training, however, there remained some tokens for each subject that were misidentified at a level significantly below chance, suggesting that truly nativelike identification of /r/ and /l/ may never be achieved by adult Japanese learners of English. 相似文献
317.
Toda J Sakagami M Goan Y Simakata M Saitoh T Horiguchi Y Sano T 《Chemical & pharmaceutical bulletin》2000,48(12):1854-1861
The thionium ions 10 generated by Pummerer reaction of N-aryl-N-methyl-3-(phenylsulfinyl)propionamides 4 caused not only an electrophilic cyclization reaction producing 2-quinolones 8, but also the formation of the vinyl sulfides 5 and 6 in favor of the latter reaction. On the other hand, the treatment of the vinyl sulfides 5 and 6 with p-toluenesulfonic acid induced cyclization to afford the 2-quinolones 8 in excellent to moderate yields, depending on the electronic properties of the aromatic ring, thus providing a convenient method for the synthesis of methoxy-2-quinolones. 相似文献
318.
The acetone-sensitized photocycloaddition of 6-chloro-1,3-dimethyluracil to alkenes affords directly 1,2-dihydrocyclobuta[]pyrimidine-4,6 (3H, 5H)-diones 1-chloro-2,4-dimethyl-2,4-diazabichyclo[4.2.0]octa-3,5-diones. 相似文献
319.
We investigate storage capacity of two types of fully connected layered neural networks with sparse coding when binary patterns are embedded into the networks by a Hebbian learning rule. One of them is a layered network, in which a transfer function of even layers is different from that of odd layers. The other is a layered network with intra-layer connections, in which the transfer function of inter-layer is different from that of intra-layer, and inter-layered neurons and intra-layered neurons are updated alternately. We derive recursion relations for order parameters by means of the signal-to-noise ratio method, and then apply the self-control threshold method proposed by Dominguez and Bollé to both layered networks with monotonic transfer functions. We find that a critical value C of storage capacity is about 0.11|a ln a|−1 (a1) for both layered networks, where a is a neuronal activity. It turns out that the basin of attraction is larger for both layered networks when the self-control threshold method is applied. 相似文献
320.
Morita and Chen's scheme of generalizing the coherent potential approximation in which the diagonal and off-diagonal randomness are included, is applied to the calculation of the electronic density of states for the linear random binary alloy. The result obtained in the three-site coherent potential approximation is reported. 相似文献