In this paper, we introduce the notion of toric special weak Fano manifolds, which have only special primitive crepant contractions. We study their structure, and in particular completely classify ...smooth toric special weak Fano $4$-folds. As a result, we can confirm that almost every smooth toric special weak Fano $4$-fold is a weakened Fano manifold, that is, a weak Fano manifold which can be deformed to a Fano manifold. KCI Citation Count: 0
The Sea of Japan back-arc system provides an exceptional opportunity to study a virtually intact continent-ocean back-arc system in which recent tectonic inversion has exposed entire sequences of ...back-arc structure on land. Moreover, Japan's dense seismic/geodetic-monitoring networks, deployed country-wide, as well as moveable pools of ocean bottom seismometers, provide a rich data set through which to investigate deep back-arc structure. Earlier investigations have produced an initial understanding of back-arc opening: timing, structural evolution, temporal/spatial patterns of magmatic activity. Many questions remain, among them, the mechanism of back-arc opening (pull-apart or trench-rollback), the dynamics of interacting plates (location of the Philippine Sea plate with time), the origin of the anomalously thick Japan Sea ocean crust, and possible influences of far-field forces (India-Asia collision). Given existing high-resolution geophysical data sets and extensive on-land exposures of back-arc sequences and structures, the Sea of Japan back-arc is a promising context in which to address both local and more universal questions of how back-arc systems evolve. Here we review the tectonic setting and geological evolution of the Sea of Japan, based our own and others' work, and briefly discuss outstanding questions that invite further investigation.
•The Sea of Japan back-arc is a virtually intact continent-ocean back-arc system.•Entire sequences of back-arc structure exposed on land by recent tectonic inversion•Substantial geophysical data archive from earthquake hazard mitigation efforts.•Studies integrating geological and geophysical data sets are ongoing.•Earlier studies clarified aspects of back-arc evolution, fundamental questions remain.
The adsorptive separation of C2H2 and CO2 via porous materials is nontrivial due to the close similarities of their boiling points and kinetic diameters. In this work, we describe a new flexible ...porous coordination polymer (PCP) Mn(bdc)(dpe) (H2bdc = 1,4-benzenedicarboxylic acid, dpe = 1,2-di(4-pyridyl)ethylene) having zero-dimensional pores, which shows an adsorbate discriminatory gate effect. The compound shows gate opening type abrupt adsorption for C2H2 but not for CO2, leading to an appreciable selective adsorption of CO2 over C2H2 at near ambient temperature (273 K). The origin of this unique selectivity, as unveiled by in situ adsorption-X-ray diffraction experiments and density functional theory calculations, is due to vastly different orientations between the phenylene ring of bdc and each gas in the nanopores. The structural change by photochemical transformation of this PCP via 2 + 2 photodimerization leads to the removal of inverse CO2/C2H2 selectivity, verifying the mechanism of the guest discriminatory gate effect.
Membrane‐type matrix metalloproteinase‐1 (MT1‐MMP) mediates cleavage of not only MMP‐2/gelatinase A for activation, but also a variety of substrates including type I collagen (reviewed in Cancer Sci ...2005; 96: 212–7). MMP‐2 activation involves tissue inhibitor of MMP (TIMP)‐2 as a bridging molecule between MT1‐MMP and pro‐MMP‐2. Thus, net activity of MT1‐MMP and MMP‐2 is regulated in a complex manner depending on TIMP‐2 concentration. During invasive growth of tumor cells in type I collagen matrix, MT1‐MMP initiates denaturation of collagen into gelatin, which is subsequently digested further by MMP‐2 adjacent to MT1‐MMP. Coordinate action of MT1‐MMP and MMP‐2 may facilitate pericellular proteolysis, and enhance not only tumor invasion/migration but also cell growth. Tetraspanins as binding proteins of MT1‐MMP regulate MT1‐MMP subcellular localization and compartmentalization, leading to efficient MMP‐2 activation and proteolysis coupled with cellular function.
(Cancer Sci 2010; 101: 843–847)
An artificial receptor for proMMP‐9 was created by fusing tissue inhibitor of MMP‐1 (TIMP‐1) with type II transmembrane mosaic serine protease (MSP‐T1). Expression of MSP‐T1 in 293T cells induced ...binding of proMMP‐9, which was processed by MMP‐2 activated by membrane type 1 MMP (MT1‐MMP). HT1080 cells transfected with the MSP‐T1 gene produced activated MMP‐9 in collagen gel, and addition of proMMP‐2 to the culture augmented it, which resulted in intensive collagen digestion. These cells metastasized into chick embryonic liver more than control cells. Treatment of HT1080 cells with concanavalin A in the presence of exogenous proMMP‐2 induced activation of not only proMMP‐2 but also proMMP‐9. Knockdown of MT1‐MMP or TIMP‐2 expression with siRNA suppressed activation of both proMMP‐2 and proMMP‐9. Transfection of TIMP‐1 siRNA suppressed cell binding and activation of proMMP‐9, but not proMMP‐2 activation. Knockdown of a disintegrin and metalloproteinase 10 (ADAM10) expression reduced cell binding and processing of proMMP‐9. These results suggest that proMMP‐9, which binds to a receptor complex containing TIMP‐1 and ADAM10, is activated by the MT1‐MMP/MMP‐2 axis, and MMP‐9 thus activated stimulates cellular proteolysis and metastasis.
ProMMP‐9 which binds to a receptor complex containing TIMP‐1 and ADAM10 is activated by MT1‐MMP/MMP‐2 axis. MMP‐9 thus activated stimulates cellular proteolysis and metastasis.
Carbon monoxide (CO) produced in many large-scale industrial oxidation processes is difficult to separate from nitrogen (N₂), and afterward, CO is further oxidized to carbon dioxide. Here, we report ...a soft nanoporous crystalline material that selectively adsorbs CO with adaptable pores, and we present crystallographic evidence that CO molecules can coordinate with copper(II) ions. The unprecedented high selectivity was achieved by the synergetic effect of the local interaction between CO and accessible metal sites and a global transformation of the framework. This transformable crystalline material realized the separation of CO from mixtures with N₂, a gas that is the most competitive to CO. The dynamic and efficient molecular trapping and releasing system is reminiscent of sophisticated biological systems such as heme proteins.
In this review, we summarize the methods of sample introduction into a gas chromatograph. For volatile organic compounds, headspace measurements and purge-trap methods have been used traditionally. ...Recently, the trapped headspace method has been used in water quality testing. In addition, various solid-state adsorption methods have been developed, including a method in which the adsorbent is placed inside a needle, while new adsorbents and their applications have also been introduced.
We herein report the divergent and convergent synthesis of coordination star polymers (CSP) by using metal–organic polyhedrons (MOPs) as a multifunctional core. For the divergent route, copper-based ...great rhombicuboctahedral MOPs decorated with dithiobenzoate or trithioester chain transfer groups at the periphery were designed. Subsequent reversible addition–fragmentation chain transfer (RAFT) polymerization of monomers mediated by the MOPs gave star polymers, in which 24 polymeric arms were grafted from the MOP core. On the other hand, the convergent route provided identical CSP architectures by simple mixing of a macroligand and copper ions. Isophthalic acid-terminated polymers (so-called macroligands) immediately formed the corresponding CSPs through a coordination reaction with copper(II) ions. This convergent route enabled us to obtain miktoarm CSPs with tunable chain compositions through ligand mixing alone. This powerful method allows instant access to a wide variety of multicomponent star polymers that conventionally have required highly skilled and multistep syntheses. MOP-core CSPs are a new class of star polymer that can offer a design strategy for highly processable porous soft materials by using coordination nanocages as a building component.
Photochromic molecules have shown much promise as molecular components of stimuli-responsive materials, but despite recent achievements in various photoresponsive materials, quantitative conversion ...in photochemical reactions in solids is hampered by the lack of intrinsic structural flexibility available to release stress and strain upon photochemical events. This issue remains one of the challenges in developing solid-state photoresponsive materials. Here, we report a strategy to realize photoresponsive crystalline materials showing quantitative reversible photochemical reactions upon ultraviolet and visible light irradiation by introducing structural flexibility into crystalline porous frameworks with a twofold interpenetration composed of a diarylethene-based ligand. The structural flexibility of the porous framework enables highly efficient photochemical electrocyclization in a single-crystal-to-single-crystal manner. CO
sorption on the porous crystal at 195 K is reversibly modulated by light irradiation, and coincident X-ray powder diffraction/sorption measurements clearly demonstrate the flexible nature of the twofold interpenetrated frameworks.Organizing photochromic molecules into 3D networks is a key strategy to access photoresponsive materials, but framework rigidity typically limits conversion efficiency. Here, the authors exploit a flexible metal-organic framework to achieve quantitative and reversible photoisomerization in a porous crystalline solid.
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