Reconciling aging and slip state evolutions from laboratory-derived canons of rate-and-state friction

The aging law and the slip law are two representative evolution laws of the rate- and state-dependent friction (RSF) law, based on canonical behaviors in three types of laboratory experiments: slide-hold-slide (SHS), velocity-step (VS), and steady-state (SS) tests. The aging law explains the SHS canon but contradicts the VS canon, and vice versa for the slip law. The later proposed composite law, which switches these two laws according to the slip rate $V$, explains both canons but contradicts the SS canon. The present study constructs evolution laws satisfying all three canons throughout the range of variables where experiments have confirmed the canons. By recompiling the three canons, we have derived constraints on the evolution law and find that the evolution rates in the strengthening phases of the SHS and VS canons are so different that complete reconciliation throughout the entire range of variables is mathematically impossible. However, for the limited range of variables probed by experiments so far, we have found that the SHS and VS canons can be reconciled without violating the SS canon by switching the evolution function according to $\Omega$, the ratio of the state $\theta$ to its steady-state value $\theta_{\rm SS}$ for the instantaneous slip rate. We could generally show that, as long as the state evolution rate $\dot \theta$ depends only on the instantaneous values of $V$ and $\theta$, simultaneous reproduction of the three canons, throughout the experimentally confirmed range, requires the aging-law-like evolution for $\Omega$ sufficiently below a threshold $\beta$ and the slip-law-like evolution for $\Omega$ sufficiently above $\beta$. The validity of the canons in existing experiments suggests $\beta \lesssim 0.01$.Comment: 90pages, 13 figure

Exploring the Base of the Volcano: A Case Study of an Active Stratovolcano, Mt. Zao, NE Japan

It is very important to explore the base of large volcanoes because older volcanoes with distinct petrological characteristics are sometimes hidden behind them. Such older volcanoes provide keys to investigate the change of magma genesis and tectonic setting during geological time. We newly found an older volcano in southern part of Zao volcano, located in Japan. We have investigated in detail the eruptive products outcropping in its southern part and found that some eruptive rocks with peculiar features form a new stratovolcano which is different from Zao volcano. We call this newly found volcano, the Hiyamizuyama volcano. We have performed K-Ar dating on the representative rocks, obtaining an old age of approximately 1.45 My. The rocks are calcalkaline andesites to dacites, having distinct chemical compositional features with respect to any other calcalkaline rock of the stages 2–6 of Zao volcano. Megacrystals and plutonic intrusions represent a distinct character of the eruptive rocks of the Hiyamizuyama volcano. The finding of this older volcano is also important in order to consider the long-term temporal variation of volcanism and magmatism in the northeastern sector of Japan

SAM-dependent enzyme-catalysed pericyclic reactions in natural product biosynthesis.

Pericyclic reactions-which proceed in a concerted fashion through a cyclic transition state-are among the most powerful synthetic transformations used to make multiple regioselective and stereoselective carbon-carbon bonds. They have been widely applied to the synthesis of biologically active complex natural products containing contiguous stereogenic carbon centres. Despite the prominence of pericyclic reactions in total synthesis, only three naturally existing enzymatic examples (the intramolecular Diels-Alder reaction, and the Cope and the Claisen rearrangements) have been characterized. Here we report a versatile S-adenosyl-l-methionine (SAM)-dependent enzyme, LepI, that can catalyse stereoselective dehydration followed by three pericyclic transformations: intramolecular Diels-Alder and hetero-Diels-Alder reactions via a single ambimodal transition state, and a retro-Claisen rearrangement. Together, these transformations lead to the formation of the dihydropyran core of the fungal natural product, leporin. Combined in vitro enzymatic characterization and computational studies provide insight into how LepI regulates these bifurcating biosynthetic reaction pathways by using SAM as the cofactor. These pathways converge to the desired biosynthetic end product via the (SAM-dependent) retro-Claisen rearrangement catalysed by LepI. We expect that more pericyclic biosynthetic enzymatic transformations remain to be discovered in naturally occurring enzyme 'toolboxes'. The new role of the versatile cofactor SAM is likely to be found in other examples of enzyme catalysis

サン イチ ドクリツ ウンドウ ニオケル ドクリツ センゲン ノ テンカイ ト ソノ イギ ヘイジョウ ニオケル イチ ジレイ ヨリ

This　year　marks　the　centennial　of　the　annexation　of　Korea　by Japan　and　the　91st　anniversary　of　the　incipience　of　the　March　First Movement．　Nonetheless，　there　is　a　relative　paucity　of　research　in Japan　into　Japanese－Korean　relations　during　this　era． 　　　More　specifically，　so　far　there　has　been　little　comprehensive research　into　the　Korean　Declaration　of　Independence　Using　primary sources　in　the　context　of　the　March　First　Movement． 　　　The　present　paper　focuses　oll　the　Declaration　itself　against　the backdrop　of　the　March　First　Movement，　and　explores　how　it　came　to be　drafted　and　spread　throughout　the　country．　The　significance　of　the Declaration　is　explored　by　examining　how　one　Japanese　person obtained　and　stored　it　in　Pyongyang． 　　　It　is　the　author’s　opinion　that　this　examination　of　the　Declaration of　Independence　as　a　historical　document　provides　a　new　perspective　on the　March　First　Movement．　Needless　to　say，　this　study　in　itself　does not　make　a　case　for　a　major　change　in　views　of　the　March　First Movement　or　of　the　Declaration’s　signatories　as‘‘traitors”，　but　it　does pose　questions　worthy　of　further　examination

9-Hydroxyellipticine inhibits telomerase activity in human pancreatic cancer cells

AbstractThere is increasing interest in identifying potent inhibitors of telomerase because the enzyme plays a crucial role in the development of cellular immortality and carcinogenesis. We hypothesized that 9-hydroxyellipticine (9-HE), an antitumor alkaloid, would inhibit telomerase activity because the drug has a unique mechanism of inhibiting phosphorylation of mutant p53 protein via inhibition of protein kinases, thereby restoring wild-type p53 function. This study was conducted to examine the effect of 9-HE on telomerase activity in human pancreatic cancer cells with differing p53 gene status. 9-HE treatment at relatively high concentrations resulted in rapid, complete inhibition of telomerase activity, irrespective of the p53 status. We conclude that 9-HE may exert a strong inhibitory effect on telomerase activity possibly through inhibition of protein kinases rather than through restoration of functional wild-type p53

The Ionized Stellar Wind in Vela X-1 During Eclipse

We present a first analysis of a high resolution X-ray spectrum of the ionized stellar wind of Vela X-1 during eclipse. The data were obtained with the High Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory. The spectrum is resolved into emission lines with fluxes between 0.02 and 1.04x10^4 ph/cm^2/s. We identify lines from a variety of charge states, including fluorescence lines from cold material, a warm photoionized wind. We can exclude signatures from collisionally ionized plasmas. For the first time we identify fluorescence lines from L-shell ions from lower Z elements. We also detect radiative recombination continua from a kT = 10 eV (1.2 x 10^5 K) photoionized optically thin gas. The fluorescence line fluxes infer the existence of optically thick and clumped matter within or outside the warm photoionized plasma.Comment: 4 pages, 2 figures, accepted by ApJ letter