Poly(olefin sulfone)s

In this chapter, we introduce poly(olefin sulfone)s and review the recent progress on the photoinduced depolymerization of poly(olefin sulfone)s as well as their applications. Poly(olefin sulfone)s combined with photobase generators (PBGs) are depolymerized upon irradiation with light. A poly(olefin sulfone) is a 1:1 alternating copolymer of olefin monomer and sulfur dioxide in which the protons on the carbons adjacent to the sulfonyl groups can be readily abstracted by a base. This removal leads to a depolymerization chain reaction, resulting in incorporation of a photobase generating chromophore that can undergo a photoinduced unzipping reaction. During this reaction, the original olefin monomer and sulfur dioxide are regenerated from the primary chain of the poly(olefin sulfone). The photoinduced depolymerization of poly(olefin sulfone)s has been investigated for a wide variety of applications, including stereolithography, printable microcircuit fabrication, and removable adhesives

The Photorefractive Effect in Liquid Crystals

This chapter summarizes the state of the art of research regarding photorefractive liquid crystals. Photorefractive effect is of interest because it can be used to obtain dynamic holograms, based on interference between dual laser beams within a liquid crystal to generate a refractive index grating. This technique can be employed in numerous diffraction optics applications, such as optical amplifiers, phase-conjugate wave generators, 3D displays, novelty filters, and optical tomography. The photorefractive effect in liquid crystals is especially pronounced, and both ferroelectric and nematic liquid crystals have been researched for this purpose, with the former showing special promise in practical applications. As an example, ferroelectric liquid crystals have been found to readily produce a refractive index grating in conjunction with a significant gain and a formation time of 900 ms

Requirement of the 3′-UTR-dependent suppression of DAZL in oocytes for pre-implantation mouse development

<div><p>Functional oocytes are produced through complex molecular and cellular processes. In particular, the contribution of post-transcriptional gene regulation mediated by RNA-binding proteins (RBPs) is crucial for controlling proper gene expression during this process. DAZL (deleted in azoospermia-like) is one of the RBPs required for the sexual differentiation of primordial germ cells and for the progression of meiosis in ovulated oocytes. However, the involvement of DAZL in the development of follicular oocytes is still unknown. Here, we show that <i>Dazl</i> is translationally suppressed in a 3′-UTR-dependent manner in follicular oocytes, and this suppression is required for normal pre-implantation development. We found that suppression of DAZL occurred in postnatal oocytes concomitant with the formation of primordial follicles, whereas <i>Dazl</i> mRNA was continuously expressed throughout oocyte development, raising the possibility that DAZL is dispensable for the survival and growth of follicular oocytes. Indeed, follicular oocyte-specific knockout of <i>Dazl</i> resulted in the production of normal number of pups. On the other hand, genetically modified female mice that overexpress DAZL produced fewer numbers of pups than the control due to defective pre-implantation development. Our data suggest that post-transcriptional suppression of DAZL in oocytes is an important mechanism controlling gene expression in the development of functional oocytes.</p></div

Molecular Design for Preparation of Hexagonal-Ordered Porous Films Based on Side-Chain-Type Liquid-Crystalline Star Polymer

Fabrication of regularly porous films by the breath-figure method has attracted much attention. The simple, low-cost technique uses the condensation of water droplets to produce these structures, but the phenomenon itself is complex, requiring control over many interacting parameters that change throughout the process. Developing a unified understanding for the molecular design of polymers to prepare ordered porous films is challenging, but required for further advancements. In this article, the effects of the chemical structure of polymers in the breath-figure technique were systematically explored using side-chain-type liquid-crystalline star polymers. The formation of porous films was affected by the structure of the polymers. Although the entire film surface of poly­(11-[4-(4-cyanobiphenyl)­oxy]­undecyl methacrylate) (<b>P11CB</b>) had a hexagonal ordered porous structure over a certain <i>M</i>_n value, regularly arranged holes did not easily form in poly­(methyl methacrylate) (<b>PMMA</b>), even though the main chain of <b>PMMA</b> is similar to that of <b>P11CB</b>. A comparison of <b>P11CB</b> and poly­(11-[(1,1′-biphenyl)-4-yloxy]­undecyl methacrylate) (<b>P11B</b>) (<b>P11CB</b> without cyano groups) showed that the local polar groups in hydrophobic polymers promoted the formation of ordered porous films. No holes were formed in poly­(4-cyanobiphenyl methacrylate) (<b>P0CB</b>) (<b>P11CB</b> without alkyl spacers) films due to its hydrophilicity. The introduction of alkyl chains in <b>P0CB</b> allowed the preparation of honeycomb-structured films by increasing the internal tension. However, alkyl chains in the side chain alone did not result in a porous structure, as in the case of poly­(undecyl methacrylate) (<b>P11</b>). Aromatic rings are also required to increase the <i>T</i>_g and improve film formability. In the present study, suitable molecular designs of polymers were found, specifically hydrophobic polymers with local polar groups, to form a regularly porous structure. Development of clear guidelines for the molecular design of polymers is the subject of our current research, which will enable the fabrication of porous films using various functional polymers

DAZL expression is suppressed in postnatal oocytes.

<p>(<b>A</b>) RT-qPCR analysis for <i>Dazl</i> in wild-type (WT) female gonads at E12.5 (n = 4), E15.5 (n = 3), P0 (n = 3), 1 week (1W) (n = 3), and 2 weeks (2W) (n = 3). <i>Mvh</i> (also known as <i>Ddx4</i>) was used as a normalizer because this gene is continuously expressed in germ cells from E12.5 to secondary follicles [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007436#pgen.1007436.ref024" target="_blank">24</a>]. The vertical axis represents relative expression level of <i>Dazl</i> to <i>Mvh</i>. Error bars represent S.D. (<b>B</b>) Western blotting analysis for DAZL from E12.5 to 2W ovaries. Two bands representing DAZL were detected. As the molecular weight of DAZL is estimated to be 33KDa, the lower band corresponds with this. However, both bands disappear in <i>Dazl</i> knockout ovaries [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007436#pgen.1007436.ref025" target="_blank">25</a>], indicating that both two bands are DAZL signals. Quantification of western data is shown below. The vertical axis represents relative DAZL expression level normalized by MVH. (<b>C</b>) Immunofluorescence analysis for DAZL (green) and FOXL2 (magenta) from E18.5 to P2, and 1W ovaries. White arrowheads indicate cystic oocytes, and yellow arrowheads indicate primordial follicles. Open arrowheads indicate oocytes showing weaker DAZL expression. Scale bar, 30μm.</p

Defective pre-implantation development is a cause of the litter size reduction.

<p>(<b>A</b>) PAS staining of control, <i>Dazl</i> 3F, and <i>Dazl 3F;Flp</i> ovaries at 5 weeks after birth. PrF, PF, SF, and AF are same as in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007436#pgen.1007436.g002" target="_blank">Fig 2C</a>. Scale bars, 100μm. (<b>B</b>) Follicle counting analysis for control (n = 15), <i>Dazl 3F</i> (n = 6), and <i>Dazl 3F;Flp</i> (n = 6) using ovarian sections at 5 weeks after birth. Error bars represent S.D. ns, no significant difference among control, <i>Dazl 3F</i>, and <i>Dazl 3F;Flp</i>. (<b>C</b>) The average number of ovulated eggs from control (n = 15), <i>Dazl 3F</i> (n = 7), and <i>Dazl 3F;Flp</i> (n = 7) females. Error bars, S.D. ns, no significant difference among control, <i>Dazl 3F</i>, and <i>Dazl 3F;Flp</i> (Tukey HSD test). (<b>D</b>) Analysis of pre-implantation development in BAC transgenic females. (Left) E3.5 embryos from control, <i>Dazl 3F</i>, and <i>Dazl 3F;Flp</i> females. Yellow arrowheads indicate abnormal embryos. Scale bars, 100μm. (Right) Proportion of embryos that developed to each stage up to blastocysts. Embryos collected from pregnant females at E3.5 were counted. Delayed embryos were cultured for an additional two days and ones that reached the blastocyst stage were added. Control (n = 75), <i>Dazl 3F</i> (n = 69) and <i>Dazl 3F;Flp</i> (n = 56).</p