Tsuyoshi Sekitani, Yoshiaki Noguchi, Ute Zschieschang, Hagen Klauk, Takao Someya.
PNAS 105, 4976-4980 (2008) | doi:10.1073/pnas.0708340105
A major obstacle to the development of organic transistors for large-area sensor, display, and circuit applications is the fundamental compromise between manufacturing efficiency, transistor performance, and power consumption. In the past, improving the manufacturing efficiency through the use of printing techniques has inevitably resulted in significantly lower performance and increased power consumption, while attempts to improve performance or reduce power have led to higher process temperatures and increased manufacturing cost. Here, we lift this fundamental limitation by demonstrating subfemtoliter inkjet printing to define metal contacts with single-micrometer resolution on the surface of high-mobility organic semiconductors to create high-performance p-channel and n-channel transistors and low-power complementary circuits. The transistors employ an ultrathin low-temperature gate dielectric based on a self-assembled monolayer that allows transistors and circuits on rigid and flexible substrates to operate with very low voltages.# インクジェット技術でそこまで小さな有機半導体が作れるとは…
# 元々博士課程に入っても必ず学位が取れるわけもなく、博士をとったって儲かるわけじゃなし
# 自然淘汰の数と考えたらいいんじゃないの？
I. Mahboob, H. Yamaguchi.
Nature Nanotechnology, Advance online publication | doi:10.1038/nnano.2008.84
The Parametron was first proposed as a logic-processing system almost 50 years ago. In this approach the two stable phases of an excited harmonic oscillator provide the basis for logic operations. Computer architectures based on LC oscillators were developed for this approach, but high power consumption and difficulties with integration meant that the Parametron was rendered obsolete by the transistor. Here we propose an approach to mechanical logic based on nanoelectromechanical systems that is a variation on the Parametron architecture and, as a first step towards a possible nanomechanical computer, we demonstrate both bit storage and bit flip operations.# やるな、NTT
# こういうふうに、昔は実用化できなかった技術をナノレベルで甦らせるプロジェクトってのも面白くない？
# ニュースソース行き当たらず…
# まさに温故知新…しかし、こういう知見が得られても対策が一向に講じられない現実…
# こういうことって、東大だけじゃなくて国のレベルですべきなんじゃないの？
# 「タコは八本、イカは十本」ってのが通用しません
Toshiaki Watanabe, Yasushi Totoki, Atsushi Toyoda, Masahiro Kaneda, Satomi Kuramochi-Miyagawa, Yayoi Obata, Hatsune Chiba, Yuji Kohara, Tomohiro Kono, Toru Nakano, M. Azim Surani, Yoshiyuki Sakaki, Hiroyuki Sasaki.
Nature, Advance online publication | doi:10.1038/nature06908
RNA interference (RNAi) is a mechanism by which double-stranded RNAs (dsRNAs) suppress specific transcripts in a sequence-dependent manner. dsRNAs are processed by Dicer to 21–24-nucleotide small interfering RNAs (siRNAs) and then incorporated into the argonaute (Ago) proteins. Gene regulation by endogenous siRNAs has been observed only in organisms possessing RNA-dependent RNA polymerase (RdRP). In mammals, where no RdRP activity has been found, biogenesis and function of endogenous siRNAs remain largely unknown. Here we show, using mouse oocytes, that endogenous siRNAs are derived from naturally occurring dsRNAs and have roles in the regulation of gene expression. By means of deep sequencing, we identify a large number of both ~25–27-nucleotide Piwi-interacting RNAs (piRNAs) and ~21-nucleotide siRNAs corresponding to messenger RNAs or retrotransposons in growing oocytes. piRNAs are bound to Mili and have a role in the regulation of retrotransposons. siRNAs are exclusively mapped to retrotransposons or other genomic regions that produce transcripts capable of forming dsRNA structures. Inverted repeat structures, bidirectional transcription and antisense transcripts from various loci are sources of the dsRNAs. Some precursor transcripts of siRNAs are derived from expressed pseudogenes, indicating that one role of pseudogenes is to adjust the level of the founding source mRNA through RNAi. Loss of Dicer or Ago2 results in decreased levels of siRNAs and increased levels of retrotransposon and protein-coding transcripts complementary to the siRNAs. Thus, the RNAi pathway regulates both protein-coding transcripts and retrotransposons in mouse oocytes. Our results reveal a role for endogenous siRNAs in mammalian oocytes and show that organisms lacking RdRP activity can produce functional endogenous siRNAs from naturally occurring dsRNAs.# peudogeneが重要であることはもはや疑いのない事実です
# う～ん、そんな画像見せられてもなぁ…
# うつかぁ…医者かぁ…どうもなぁ…
