35 research outputs found
Discriminatory Analysis of Discharged Gas and Heavy Oils in the Sea
Gas and heavy oils discharged into the sea were discriminated using gas chromatography-mass spectrometry (GC-MS), gas chromatography (GC-FID) and infrared spectroscopy (FT-IR). The GC-MS focused on the determination of the biomarkers, such as hopanes, norhopanes and triaromatic steranes, which were detected from heavy oil, but were hardly observed from gas oil. The discriminative analysis using GC-FID of the methylnaphthalenes showed a discrimination with a ratio of ((2-methylnaphthalene)+(1-methylnaphthalene))/tridecane. The ratios for the gas oils were less than 1.0, but those for the heavy oils were 1.0 or higher. These oils were distinguished in comparison to the FT-IR data from three peaks at 811, 742 and 723 cm-1 which were assigned to the CH bending modes for 2 and 4 hydrogens and a methylene framework, respectively. The order for the heavy oil was 723 < 742 < 811 cm-1, while that for the gas oil was 742 < 811< 723 cm-1. Moreover, the absorption intensity at 1603 cm-1 for the heavy oil was higher than that for the gas oil. An absorption at 475 cm-1 (out-of-plane ring vibration) was also observed for the heavy oil, but not for the gas oil. In combination of the GC results with the FT-IR, 2-methylnaphthalene and 1-methylnaphthalene were contained in greater amounts in the heavy oil than in the gas oil, which were derived from the light cycle oil. Thus, the heavy oils discharged from ships and drifted on the seashore were discriminated from the original heavy oils and the gas oils.Key words: Heavy oil, Gas oil, Identification, Methylnaphthalene, Hopan
Novel method to rescue a lethal phenotype through integration of target gene onto the X-chromosome.
The loss-of-function mutations of serine protease inhibitor, Kazal type 1 (SPINK1) gene are associated with human chronic pancreatitis, but the underlying mechanisms remain unknown. We previously reported that mice lacking Spink3, the murine homologue of human SPINK1, die perinatally due to massive pancreatic acinar cell death, precluding investigation of the effects of SPINK1 deficiency. To circumvent perinatal lethality, we have developed a novel method to integrate human SPINK1 gene on the X chromosome using Cre-loxP technology and thus generated transgenic mice termed "X-SPINK1". Consistent with the fact that one of the two X chromosomes is randomly inactivated, X-SPINK1 mice exhibit mosaic pattern of SPINK1 expression. Crossing of X-SPINK1 mice with Spink3+/- mice rescued perinatal lethality, but the resulting Spink3-/-;XXSPINK1 mice developed spontaneous pancreatitis characterized by chronic inflammation and fibrosis. The results show that mice lacking a gene essential for cell survival can be rescued by expressing this gene on the X chromosome. The Spink3-/-;XXSPINK1 mice, in which this method has been applied to partially restore SPINK1 function, present a novel genetic model of chronic pancreatitis
Safety of fondaparinux to prevent venous thromboembolism in Japanese patients undergoing colorectal cancer surgery: a multicenter study
Cellulose nanofiber paper as an ultra flexible nonvolatile memory
On the development of flexible electronics, a highly flexible nonvolatile memory, which is an important circuit component for the portability, is necessary. However, the flexibility of existing nonvolatile memory has been limited, e.g. the smallest radius into which can be bent has been millimeters range, due to the difficulty in maintaining memory properties while bending. Here we propose the ultra flexible resistive nonvolatile memory using Ag-decorated cellulose nanofiber paper (CNP). The Ag-decorated CNP devices showed the stable nonvolatile memory effects with 6 orders of ON/OFF resistance ratio and the small standard deviation of switching voltage distribution. The memory performance of CNP devices can be maintained without any degradation when being bent down to the radius of 350 μm, which is the smallest value compared to those of existing any flexible nonvolatile memories. Thus the present device using abundant and mechanically flexible CNP offers a highly flexible nonvolatile memory for portable flexible electronics.Nagashima, K., Koga, H., Celano, U. et al. Cellulose Nanofiber Paper as an Ultra Flexible Nonvolatile Memory. Sci Rep 4, 5532 (2014). https://doi.org/10.1038/srep05532
Nanostructures Integrated with a Nanochannel for Slowing Down DNA Translocation Velocity for Nanopore Sequencing
Nanoscale Size-Selective Deposition of Nanowires by Micrometer Scale Hydrophilic Patterns
Controlling the post-growth assembly of nanowires is an important challenge in the development of functional bottom-up devices. Although various methods have been developed for the controlled assembly of nanowires, it is still a challenging issue to align selectively heterogeneous nanowires at desired spatial positions on the substrate. Here we report a size selective deposition and sequential alignment of nanowires by utilizing micrometer scale hydrophilic/hydrophobic patterned substrate. Nanowires dispersed within oil were preferentially deposited only at a water/oil interface onto the hydrophilic patterns. The diameter size of deposited nanowires was strongly limited by the width of hydrophilic patterns, exhibiting the nanoscale size selectivity of nanowires deposited onto micrometer scale hydrophilic patterns. Such size selectivity was due to the nanoscale height variation of a water layer formed onto the micrometer scale hydrophilic patterns. We successfully demonstrated the sequential alignment of different sized nanowires on the same substrate by applying this size selective phenomenon. D esigning the post-growth assembly of nanowires on the substrate offers a fascinating way to explore novel functional nanoscale devices. In general, such assembling processes of nanowires can be performed at relatively low temperatures , which are much lower than typical nanowire growth temperatures This study proposes a size selective deposition technique and sequential alignment of nanowires by utilizing micrometer scale hydrophilic/hydrophobic patterned substrate. We utilized nanowires dispersed within oil, which were preferentially deposited only at a water/oil interface onto the hydrophilic patterns. We found the nanoscale size selectivity of nanowires deposited onto micrometer scale hydrophilic patterns. This nanoscale size selectivity by micrometer scale patterns can be extended to the sequential alignment of different sized nanowires on the same substrate. Result
Identifying DNA methylation in a nanochannel
DNA methylation is a stable epigenetic modification, which is well known to be involved in gene expression regulation. In general, however, analyzing DNA methylation requires rather time consuming processes (24–96 h) via DNA replication and protein modification. Here we demonstrate a methodology to analyze DNA methylation at a single DNA molecule level without any protein modifications by measuring the contracted length and relaxation time of DNA within a nanochannel. Our methodology is based on the fact that methylation makes DNA molecules stiffer, resulting in a longer contracted length and a longer relaxation time (a slower contraction rate). The present methodology offers a promising way to identify DNA methylation without any protein modification at a single DNA molecule level within 2 h