Etching-Assisted Ablation of the UV-Transparent Fluoropolymer CYTOP Using Various Laser Pulse Widths and Subsequent Microfluidic Applications.

This work demonstrated the surface microfabrication of the UV-transparent fluoropolymer CYTOP (perfluoro 1-butenyl vinyl ether), by etching-assisted ablation using lasers with different pulse widths. In previous studies, we developed a technique for CYTOP microfluidic fabrication using laser ablation followed by etching and annealing. However, this technique was not suitable for some industrial applications due to the requirement for prolonged etching of the irradiated areas. The present work developed a faster etching-assisted ablation method in which the laser ablation of CYTOP took place in fluorinated etching solvent and investigated into the fabrication mechanism of ablated craters obtained from various pulse width lasers. The mechanism study revealed that the efficient CYTOP microfabrication can be achieved with a longer pulse width laser using this technique. Therefore, the rapid, high-quality surface microfabrication of CYTOP was demonstrated using a conventional nanosecond laser. Additionally, Microfluidic systems were produced on a CYTOP substrate via the new etching-assisted laser ablation process followed by annealing within 1 h, which is faster than the prior work of the microfluidic chip fabrication. Subsequently, CYTOP and polydimethylsiloxane substrates were bonded to create a 3D microfluidic chip that allowed for a clear microscopic image of the fluid boundary.

An ab initio study of nuclear volume effects for isotope fractionations using two-component relativistic methods.

We investigate the accuracy of two-component Douglas-Kroll-Hess (DKH) methods in calculations of the nuclear volume term (≡ lnK(nv)) in the isotope fractionation coefficient. lnK(nv) is a main term in the chemical equilibrium constant for isotope exchange reactions in heavy element. Previous work based on the four-component method reasonably reproduced experimental lnK(nv) values of uranium isotope exchange. In this work, we compared uranium reaction lnK(nv) values obtained from the two-component and four-component methods. We find that both higher-order relativistic interactions and spin-orbit interactions are essential for quantitative description of lnK(nv). The best alternative is the infinite-order Douglas-Kroll-Hess method with infinite-order spin-orbit interactions for the one-electron term and atomic-mean-field spin-same-orbit interaction for the two-electron term (IODKH-IOSO-MFSO). This approach provides almost equivalent results for the four-component method, while being 30 times faster. The IODKH-IOSO-MFSO methodology should pave the way toward computing larger and more general molecules beyond the four-component method limits.

Analysis of ammonia toxicity in landfill leachates.

Toxicity identification evaluation (TIE) phase I manipulations and toxicity test with D. magna were conducted on leachates from an industrial waste landfill site in Japan. Physicochemical analysis detected heavy metals at concentrations insufficient to account for the observed acute toxicity. The graduated pH and aeration manipulations identified the prominent toxicity of ammonia. Based on joint toxicity with additive effects of unionized ammonia and ammonium ions, the unionized ammonia toxicity (LC50,NH3(aq)) was calculated as 3.3 ppm, and the toxicity of ammonium ions (LC50,NH4 (+) ) was calculated as 222 ppm. Then, the contribution of ammonia toxicity in the landfill leachate toxicity was calculated as 58.7 vol% of the total toxicity in the landfill leachate. Other specific toxicants masked by ammonia's toxicity were detected. Contribution rate of the toxicants other than by ammonia was 41.3 vol% of the total toxicity of the landfill leachate.

Expression pattern of the coparyl diphosphate synthase gene in developing rice anthers.

Rice anthers contain high concentrations of gibberellins A(4) and A(7). To understand their physiological roles, we examined the site of their biosynthesis by analyzing the expression pattern of a gene (OsCPS) encoding coparyl diphosphate synthase in developing rice flowers. Expression was apparent in the anthers 1-2 days before flowering, and CPS mRNA accumulated in the maturing pollen.

Regulation and a conserved intron sequence of liguleless3/4 knox class-I homeobox genes in grasses.

The nine class-I maize (Zea mays L.) knox genes are putative transcription factors normally expressed in shoot apices, but not in leaves. knotted1 (kn1) seems to function in shoot apical meristem maintenance, and rough sheath1 (rs1)-like genes may act in internode elongation. The function of liguleless3 (lg3)-type genes is still unknown. Here, we characterized lg3 as well as the two most closely related genes liguleless4a (lg4a, formerly knox11) and liguleless4b (lg4b, formerly knox5). We termed this subclass of knox genes lg3/4 genes. We studied the expression patterns of lg3/4 genes and compared their sequences. We obtained knockout mutants of lg3 by finding Mu transposon insertions into exons. Our results show that lg3 was not essential for plant development, and that lg4a and lg4b were likely to encode the redundant function. In addition, lg4a but not lg4b was ectopically expressed in the Lg4-O mutant, suggesting that this mutant was affected at the lg4a locus. We found that the lg3 gene was unique among knox genes as it was co-induced in the leaves of leaf mutants that ectopically expressed knox genes in the leaves. The leaf phenotype expressed in the dominant Rs1-O mutant was not altered when lg3 function was removed using the knockout. Genomic sequence comparisons of lg3, lg4a and lg4b from maize and the two homologous genes, osh6 and osh71, from rice revealed a 14-bp phylogenetic footprint in intron II. This sequence was conserved in nucleotide composition, position and polarity in the lg3/4 genes of divergent grasses representing six Gramineae subfamilies. In an independent experiment, this same conserved sequence was found in a yeast reverse one-hybrid screen for putative binding sites of the LG3 homeodomain protein. Distribution of this 14-bp sequence was examined within the public rice database. The possible function of this sequence in regulation of lg3/4 genes is discussed.

The rice pyruvate decarboxylase 3 gene, which lacks introns, is transcribed in mature pollen.

The rice pyruvate decarboxylase 3 gene (PDC3), which has no introns, was previously postulated to be a pseudogene because no PDC3 mRNA had been detected, even under anaerobic conditions. However, in this study, it was found that rice PDC3 transcripts accumulated in panicles after heading. Within anthers obtained from the panicles, PDC3 was shown to be transcribed in mature pollen by in situ hybridization. These results suggest that the rice PDC3 is a functional gene. Its product may play a role in aerobic alcoholic fermentation in mature pollen.