133 research outputs found
Visible light-driven dye-sensitized photocatalytic hydrogen production by porphyrin and its cyclic dimer and trimer: effect of multi-pyridyl-anchoring groups on photocatalytic activity and stability
The monomer, dimer, and trimer of 5,15-diphenyl-10,20-di(pyridin-4-yl)porphyrin are used to investigate the multianchoring effect on TiO2 for visible light-driven photocatalytic hydrogen production in a water medium. Further, the porphyrin trimer is prepared and analyzed by nuclear magnetic resonance (NMR) spectroscopy, absorption spectroscopy, electrochemical voltammetry, fast atom bombardment (FAB) mass spectroscopy, and density functional theory (DFT) computation. The results of this study indicate that the peak intensities of the absorption spectra increase as the number of porphyrin units increases, while changes could be barely observed in the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gaps. The porphyrin dimer in a 1 wt % Pt-loaded TiO2 powder photocatalyst system exhibited optimal hydrogen production performance in a stable state over a period of 80 h and at a superior rate of 1023 μmol·g–1·h–1. Further, the stability of the photocatalytic system was systematically investigated using films containing dyes on 1 wt % Pt-loaded TiO2/FTO. For a film containing the dimer, almost no change was observed in the hydrogen-bond coordination mode of the dimer and the photocurrent during the photocatalytic reaction. However, the photocurrents of the monomer and trimer were altered during visible light irradiation without altering the coordination mode, indicating that the arrangements and orientations of the porphyrins on TiO2 surfaces were altered. These results indicate that the presence of multiple anchoring groups enhance the stability of the photocatalytic system and the rate of hydrogen production
Craniocervical junction abnormalities with atlantoaxial subluxation caused by ventral subluxation of C2 in a dog
Craniocervical junction abnormalities with atlantoaxial subluxation caused by ventral subluxation of C2 were diagnosed in a 6-month-old female Pomeranian with tetraplegia as a clinical sign. Lateral survey radiography of the neck with flexion revealed atlantoaxial subluxation with ventral subluxation of C2. Computed tomography revealed absence of dens and atlanto-occipital overlapping. Magnetic resonance imaging showed compression of the spinal cord and indentation of caudal cerebellum. The diagnosis was Chiari-like malformation, atlantoaxial subluxation with ventral displacement of C2, atlanto-occipital overlapping, and syringomyelia. The dog underwent foramen magnum decompression, dorsal laminectomy of C1, and ventral fixation of the atlantoaxial joint. Soon after the operation, voluntary movements of the legs were recovered. Finally, the dog could stand and walk without assistance. The dog had complicated malformations at the craniocervical junction but foramen magnum decompression and dorsal laminectomy for Chiari-like malformation, and ventral fixation for atlantoaxial subluxation resulted in an excellent clinical outcome.Keywords: Atlantoaxial subluxation, Atlanto-occipital overlapping, Chiari-like malformation, Craniocervical junction abnormalities, Foramen magnum decompression
Dynamic organization of chromatin domains revealed by super-resolution live-dell imaging
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here by permission of Cell Press for personal use, not for redistribution. The definitive version was published in Molecular Cell 67 (2017): 282-293, doi:10.1016/j.molcel.2017.06.018.The eukaryotic genome is organized within cells as chromatin. For proper information
output, higher-order chromatin structures can be regulated dynamically. How such
structures form and behave in various cellular processes remains unclear. Here, by
combining super-resolution imaging (photoactivated localization microscopy, PALM)
and single nucleosome tracking, we developed a nuclear imaging system to visualize the
higher-order structures along with their dynamics in live mammalian cells. We
demonstrated that nucleosomes form compact domains with a peak diameter of ~160
nm and move coherently in live cells. The heterochromatin-rich regions showed more
domains and less movement. With cell differentiation, the domains became more
apparent, with reduced dynamics. Furthermore, various perturbation experiments
indicated that they are organized by a combination of factors, including cohesin and
nucleosome–nucleosome interactions. Notably, we observed the domains during mitosis,
suggesting that they act as building blocks of chromosomes and may serve as
information units throughout the cell cycle.This work
was supported by MEXT and JSPS grants (23115005 and 16H04746, respectively) and
a JST CREST grant (JPMJCR15G2).2018-07-1
Environmental Load Evaluation of Reuse Parts for Automobiles
Abstract Reuse parts are parts removed from scrap automobiles that can be still used. In general, reuse parts reduce not only the cost for replacement of failed parts but also the environmental load. This study quantitatively evaluates environmental loads, such as the amount of CO2 emission during the production of brand new parts, in order to quantify the beneficial effect of the reuse parts. The amount of CO2 emission can be calculated from the power consumption and operating time of each tool and machine employed. Reuse parts generate 0.62 kg of CO2 per automobile when produced, which corresponds to 1,212 kg per year. However, the amount of CO2 emitted from scrapping automobiles without producing new replacement parts is 3,063 kg per year. Therefore, the production of replacement parts emits three times less CO2 than scrapping
Nonclosure technique with saline-coupled bipolar electrocautery in management of the cut surface after distal pancreatectomy
金沢大学医学部附属病院肝胆膵・移植外科 Background/Purpose: Management of the pancreatic remnant after distal pancreatectomy is still debated, the most serious complication is development of a pancreatic fistula. We developed a nonclosure technique with saline-coupled bipolar electrocautery for preventing fistula formation after distal pancreatectomy as an alternative to traditional stump closure methods. Methods: The distinguishing feature of this technique is nonclosure of the stump, relying instead upon dependable ligation of the main pancreatic duct and sealing of the cut surface by shrinkage accomplished by low-temperature coagulation using saline-coupled bipolar electrocautery. A recent addition has been intraoperative stenting of the remnant pancreatic duct. Results: To date we have used the nonclosure technique in 40 cases, among which 5 (12.5%) developed fistulas: 4 in the nonstenting subgroup (14.8%) and 1 in the stenting subgroup (7.7%). According to a recent classification, 4 fistulas were considered grade A; 1, grade B; and 0, grade C. The grade B patient did not undergo stenting. Conclusion: Our preliminary experience should prompt more widespread evaluation of the nonclosure technique. © Springer Japan 2008
Single nucleosome imaging reveals loose genome chromatin networks via active RNA polymerase II.
© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nagashima, R., Hibino, K., Ashwin, S. S., Babokhov, M., Fujishiro, S., Imai, R., Nozaki, T., Tamura, S., Tani, T., Kimura, H., Shribak, M., Kanemaki, M. T., Sasai, M., & Maeshima, K. Single nucleosome imaging reveals loose genome chromatin networks via active RNA polymerase II. Journal of Cell Biology, 218(5), (2019):1511-1530, doi:10.1083/jcb.201811090.Although chromatin organization and dynamics play a critical role in gene transcription, how they interplay remains unclear.
To approach this issue, we investigated genome-wide chromatin behavior under various transcriptional conditions in living
human cells using single-nucleosome imaging. While transcription by RNA polymerase II (RNAPII) is generally thought to
need more open and dynamic chromatin, surprisingly, we found that active RNAPII globally constrains chromatin movements.
RNAPII inhibition or its rapid depletion released the chromatin constraints and increased chromatin dynamics. Perturbation
experiments of P-TEFb clusters, which are associated with active RNAPII, had similar results. Furthermore, chromatin
mobility also increased in resting G0 cells and UV-irradiated cells, which are transcriptionally less active. Our results
demonstrated that chromatin is globally stabilized by loose connections through active RNAPII, which is compatible with
models of classical transcription factories or liquid droplet formation of transcription-related factors. Together with our
computational modeling, we propose the existence of loose chromatin domain networks for various intra-/interchromosomal
contacts via active RNAPII clusters/droplets.We thank Dr. Y. Hiromi, Dr. S. Hirose, Dr. H. Seino, and Dr. S. Ide for critical reading of this manuscript. We thank Dr. S. Ide, Dr. D. Kaida, Dr. T. Nagai, Dr. V. Doye, Dr. G. Felsenfeld, and Dr. K. Horie for valuable help and materials. We also thank the Maeshima laboratory members for helpful discussions and support.
R. Imai and T. Nozaki are Japan Society for the Promotion of Science Fellows. R. Nagashima was supported by 2017 SOKENDAI Short-Stay Study Abroad Program. This work was supported by a Japan Society for the Promotion of Science grant (16H04746), Takeda Science Foundation, RIKEN Pioneering Project, a Japan Science and Technology Agency Core Research for Evolutional Science and Technology grant (JPMJCR15G2), a National Institute of General Medical Sciences grant (R01-GM101701), and National Institute of Genetics JOINT (2016-A2 (6))
Molecular database for classifying Shorea species (Dipterocarpaceae) and techniques for checking the legitimacy of timber and wood products
The extent of tropical forest has been declining, due to over-exploitation and illegal logging activities. Large quantities of unlawfully extracted timber and other wood products have been exported, mainly to developed countries. As part of the export monitoring effort, we have developed methods for extracting and analyzing DNA from wood products, such as veneers and sawn timbers made from dipterocarps, in order to identify the species from which they originated. We have also developed a chloroplast DNA database for classifying Shorea species, which are both ecologically and commercially important canopy tree species in the forests of Southeast Asia. We are able to determine the candidate species of wood samples, based on DNA sequences and anatomical data. The methods for analyzing DNA from dipterocarp wood products may have strong deterrent effects on international trade of illegitimate dipterocarp products. However, the method for analyzing DNA from wood is not perfect for all wood products and need for more improvement, especially for plywood sample. Consequently, there may be benefits for the conservation of tropical forests in Southeast Asia. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10265-010-0348-z) contains supplementary material, which is available to authorized users
Management of postoperative hemorrhage associated with factor VIII inhibitor: report of a case
This report presents a case that was successfully treated for acquired factor VIII inhibitor after extensive visceral surgery. A 71-year-old male who underwent surgery for bile duct cancer had active bleeding in the abdominal drainage tube on postoperative day (POD) 5, and prolonged activated partial thromboplastin time (aPTT) was detected (83.1 s) on POD 7. An extensive coagulation work-up revealed factor VIII deficiency (1 %), and a diagnosis of an acquired factor VIII deficiency was established when a factor VIII inhibitor of 8 Bethesda units was demonstrated. The patient was treated with activated prothrombin complex concentrate (aPCCs) and bloody discharge was stopped within 3 days. Inhibitor elimination was started using prednisolone on POD 20; rituximab, was administered on POD 74 and 81. Factor VIII inhibitor had disappeared by POD 124, and factor VIII (72 %) and aPTT recovered to 45.9 s. This case report demonstrated the efficacy of aPCCs and rituximab in the treatment of acquired hemophilia associated with visceral surgery. © 2012 Springer
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