Auslander--Reiten theory in extriangulated categories

The notion of an extriangulated category gives a unification of existing theories in exact or abelian categories and in triangulated categories. In this article, we develop Auslander--Reiten theory for extriangulated categories. This unifies Auslander--Reiten theories developed in exact categories and triangulated categories independently. We give two different sets of sufficient conditions on the extriangulated category so that existence of almost-split extensions becomes equivalent to that of an Auslander--Reiten--Serre duality. We also show that existence of almost-split extensions is preserved under taking relative extriangulated categories, ideal quotients, and extension-closed subcategories. Moreover, we prove that the stable category $\underline{\mathscr{C}}$ of an extriangulated category $\mathscr{C}$ is a $\tau$-category if $\mathscr{C}$ has almost split extensions and source morphisms. This gives various consequences on $\underline{\mathscr{C}}$, including Igusa--Todorov's Radical Layers Theorem. In particular, the associated completely graded category of $\underline{\mathscr{C}}$ is equivalent to the complete mesh category of the Auslander-Reiten species of $\underline{\mathscr{C}}$.Comment: Revised, 40 pages. Section 6 and 7 adde

Inauguration of the Master Course in Tropical Medicine at Nagasaki University:a milestone in tropical medical education in Japan.

We now live in a world where the threat of emerging and re-emerging infectious diseases crosses continental and national borders. In recognition of this trend the world realizes the importance of nurturing expertise in the control of infectious diseases based on sound knowledge, experience, and evidence. The introduction of a Master of Tropical Medicine course at the Graduate School of Biomedical Sciences in Nagasaki University, Japan is expected to provide a whole new opportunity for eager doctors to acquire necessary knowledge and skills to combat the world-wide burden of infectious diseases

Auslander--Reiten theory in extriangulated categories

The notion of an extriangulated category gives a unification of existing theories in exact or abelian categories and in triangulated categories. In this article, we demonstrate it for Auslander-Reiten theory. We give two different sets of sufficient conditions on the extriangulated category so that existence of almost-split extensions becomes equivalent to that of an Auslander-Reiten-Serre duality

A 750-MHz Electronically Tunable Resonator Using Microstrip Line Couplers for Electron Paramagnetic Resonance Imaging of a Mouse Tumor-Bearing Leg

Objective: The purpose of this work was to develop an electronically tunable resonator operating at 750 MHz for continuous-wave electron paramagnetic resonance (CW-EPR) imaging of a mouse tumor-bearing leg. Methods: The resonator had a multi-coil parallel-gap structure with a sample space of 16 mm in diameter and 20 mm in length. Microstrip line couplers were used in conjunction with varactor diodes to enable resonance frequency adjustment and to reduce the nonlinear effects of the varactor diodes. The resonator was modeled by the finite-element method and a microwave circuit simulation was performed to clarify its radiofrequency characteristics. Results: A tunable resonator was evaluated in terms of its resonance frequency, tunable frequency band, and conversion efficiency of the RF magnetic field. The developed resonator provided a tunable frequency band of 4 MHz at a central frequency of 747 MHz and a conversion efficiency of 34 mu T/W-1/2. To demonstrate the application of this tunable resonator to EPR imaging, three-dimensional EPR images of a sample solution and a mouse tumor-bearing leg were obtained. Conclusion: The developed tunable resonator satisfied our initial requirements for in vivo EPR imaging and may be able to be further improved using the present finite-element and circuit models if any problems arise during future practical applications. Significance: This work may help to promote EPR imaging of tumor-bearing mice in cancer-related studies

Process Development of a CRF₁ Receptor Antagonist Based on the Selective Chlorination of a Benzimidazolone via Chlorine Migration

A practical synthesis of 4-chloro-2-(2,4-dichloro-6-methylphenoxy)-1-methyl-7-(pentan-3-yl)-1<i>H</i>-benzo­[<i>d</i>]­imidazole <b>1</b>, a novel corticotropin-releasing factor 1 (CRF₁) receptor antagonist, has been developed. The key chemical transformations were (1) a novel regioselective chlorination at the 4-position of a benzimidazolone intermediate with 1,3,5-trichloro-1,3,5-triazinane-2,4,6-trione in the presence of sodium tertiary butoxide via a chlorine migration mechanism (<i>N</i>-3 to <i>C</i>-4) and (2) a one-pot, three-step dehydroxylation sequence (dehydration, isomerization, and hydrogenation) of a benzylic tertiary alcohol in the presence of <i>p</i>-toluenesulfonic acid and a Pd catalyst. The endgame was also optimized for quality and yield improvement. The chromatography-free six-step process starting from a commercially available material afforded <b>1</b> in 35% overall yield and greater than 99% purity

Electron Paramagnetic Resonance Implemented with Multiple Harmonic Detections Successfully Maps Extracellular pH In Vivo

Extracellular acidification indicates a metabolic shift in cancer cells and is, along with tissue hypoxia, a hallmark of tumor malignancy. Thus, non-invasive mapping of extracellular pH (pHe) is essential for researchers to understand the tumor microenvironment and to monitor tumor response to metabolism-targeting drugs. While electron paramagnetic resonance (EPR) has been successfully used to map pHe in mouse xenograft models, this method is not sensitive enough to map pHe with a moderate amount of exogenous pH-sensitive probes. Here, we show that a modified EPR system achieves twofold higher sensitivity by using the multiple harmonic detection (MHD) method and improves the robustness of pHe mapping in mouse xenograft models. Our results demonstrate that treatment of a mouse xenograft model of human-derived pancreatic ductal adenocarcinoma cells with the carbonic anhydrase IX (CAIX) inhibitor U-104 delays tumor growth with a concurrent tendency toward further extracellular acidification. We anticipate that EPR-based pHe mapping can be expanded to monitor the response of other metabolism-targeting drugs. Furthermore, pHe monitoring can also be used for the development of improved metabolism-targeting cancer treatments