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31.
Transfer of solar radiation in the combined atmosphere and ocean system is evaluated by the matrix operator method. Derivation of the reflection and transmission matrices required for applying the matrix method is discussed introducing the shadowing effect of light by the ocean waves. Spectral and total radiation fields just above and below the ocean surface, as well as the top of the atmosphere, are numerically calculated using several optical models of the atmosphere, ocean, and wind roughened ocean surface. Dependencies of radiance and flux reflectivity on the wind velocity and optical property of the ocean body are discussed in detail.  相似文献   
32.
We introduce a property of forcing notions, called the anti-, which comes from Aronszajn trees. This property canonically defines a new chain condition stronger than the countable chain condition, which is called the property .In this paper, we investigate the property . For example, we show that a forcing notion with the property does not add random reals. We prove that it is consistent that every forcing notion with the property has precaliber 1 and for forcing notions with the property fails. This negatively answers a part of one of the classical problems about implications between fragments of .  相似文献   
33.
A new class of ferroelectric coordination‐based polymers has been developed by the self‐assembly of lipophilic zinc porphyrin ( ZnP ) and ditopic bridging ligands. The ligands contain dipolar benzothiadiazole or fluorobenzene units, which are axially coordinated to ZnP with the dipole moments oriented perpendicular to the coordination axes. The coordination‐based polymers show ferroelectric characteristics in the liquid crystalline state, as revealed by distinctive hysteresis in the polarization–electric field (PE) loops and inversion current peaks in current–voltage (IV) loops. The observed ferroelectric properties are explainable by flip–flop rotation of the dipolar axle ligands induced by the applied electric field, as demonstrated by the positive‐up–negative‐down (PUND) measurements. The present system provides a new operating principle in supramolecular ferroelectrics.  相似文献   
34.
Pyrrole-imidazole polyamide (PIP) is a nuclease-resistant novel compound that inhibits gene expression through binding to the minor groove of DNA. Human aurora kinase-A (AURKA) and -B (AURKB) are important regulators in mitosis during the cell cycle. In this study, two specific PIPs (PIP-A and PIP-B) targeting AURKA and AURKB promoter regions were designed and synthesized, and their biological effects were investigated by several in vitro assays. PIP-A and PIP-B significantly inhibited the promoter activities, mRNA expression, and protein levels of AURKA and AURKB, respectively, in a concentration-dependent manner. Moreover, 1:1 combination treatment with both PIPs demonstrated prominent antiproliferative synergy (CI value [ED(50)] = 0.256) to HeLa cells as a result of inducing apoptosis-mediated severe catastrophe of cell-cycle progression. The novel synthesized PIP-A and PIP-B are potent and specific gene-silencing agents for AURKA and AURKB.  相似文献   
35.
We present the synthesis and structure of various protein nanotubes comprised of an alternate layer-by-layer (LbL) assembly using a polycation as an electrostatic glue. The nanotubes were fabricated by sequential LbL depositions of positively charged polycations and negatively charged proteins into a porous polycarbonate (PC) membrane, followed by release of the cylindrical core by quick dissolution of the template with CH(2)Cl(2). This procedure provides a variety of protein nanotubes without interlayer cross-linking. The three-cycle depositions of poly-L-arginine (PLA) and human serum albumin (HSA, M(w)=66.5 kDa) into the porous PC template (pore diameter, D(p)=400 nm) yielded well-defined (PLA/HSA)(3) nanotubes with an outer diameter of 419+/-29 nm and a wall thickness of 46+/-8 nm, revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. The outer diameter of the tubules can be controlled by the pore size of the template (200-800 nm), whereas the wall thickness is always constant, independent of the D(p) value. The (PEI/HSA)(3) (PEI: polyethylenimine) nanotubes showed a slightly thin wall of 39+/-5 nm. CD spectra of the multilayered (PEI/HSA)(n) film on a flat quartz plate suggested that the secondary structure of HSA between the polycations was almost the same as that in aqueous solution. The three-cycle LbL depositions of PLA and ferritin (M(w)=460 kDa) or myoglobin (Mb, M(w)=1.7 kDa) into the porous PC membrane also gave cylindrical hollow structures. The wall thickness of the (PLA/ferritin)(3) and (PLA/Mb)(3) nanotubes were 55+/-5 nm and 31+/-4 nm; it depends on the globular size of the protein (ferritin>HSA>Mb). The individual ferritin molecule was clearly seen in the tubular walls by SEM and TEM measurements.  相似文献   
36.
37.
Cover Picture     
The cover picture shows how protein matrices can regulate the spatial arrangement and orientation of a heme-based donor (Zn-heme: ZnPP)-sensitizer (Ru2+(bpy)3)-acceptor (cyclic viologen: BXV4+) triad. A U-shape conformation of the triad without protein matrix changes into a triangle arrangement by incorporation into apocytochrome b562 (Cyt-b562), or into a further extended conformation by apomyoglobin (Mb) matrix. The electron transfer pathways and the lifetimes of the photoinduced charge-separated states were remarkably affected by the protein wrapping effect.  相似文献   
38.
Bolaamphiphilic tetraresorcinolporphyrins with eight long side chains (octopusporphyrins) and their metal complexes form monolayered assemblies in bulk aqueous solution. The nano-structure, the photoinduced electron transfers and the O2 coordination of these octopusporphyrin assemblies are described. In the micellar fibers of 1a and 1b, a unique spherical arrangement of eight methyl groups on both sides of the porphyrin ring plane provides hydrophobic porphyrin centers which align in a string of pearls. Exciton calculations indicated a tilt stacking porphyrins arrangement with a separation of 11 Å. These fibers fluoresced strongly; electron transfer reaction was therefore observed between the porphyrin center and hydrophobic quenchers as well as hydrophilic quenchers. The fibers were also active as photocatalysts in the reduction of dimethylviologen by triethanolamine. Octopusporphyrins with different metal centers can also produce fibrous aggregates, for example, H2P/Zn(II)P and Zn(II)P/Fe(III)P couples. The fluorescence quenching of Zn(II)P in the Zn(II)P/Fe(III)P hybrid fibers can be ascribed to the intermolecular electron transfer within the fibers. In H2P/Zn(II)P couple, excitation energy transfer from excited Zn1*P to H2P occurred after photoexcitation. Octopusporphyrin with four dialkylglycerophosphocholine groups on both sides of the ring plane ( 2b ) forms spherical unilamellar vesicles. Based on cryomicroscopy, a white line was observed with a diameter of 15 Å in the middle of the membrane which are obviously a porphyrin layer with low molecular packing. The octopusheme ( 2c ) vesicles prepared in a similar manner with 20-fold excess molar coexistence of 1-dodecyl-2-methylimidazole (DMIm) can bind and release oxygen reversibly at 25°C. Moreover, water-soluble octopusporphyrin ( 3a ) produced fluorescent and non-fluorescent monolayer assemblies by anion exchange of the head groups, e.g. 3a with sodium perchlorate showed planar sheets. An exciton calculation is consistent with a two-dimensional arrangement with porphyrin separations of 25.6 and 17.4 Å in the x- and y-directions, respectively. External addition of negatively charged electron acceptors, naphtoquinone sulfonate and anthraquinone sulfonate, led to partial quenching of the fluorescence of the central porphyrin layer. The results have been evaluated using equations derived for this special quenching. © 1998 John Wiley & Sons, Ltd.  相似文献   
39.
This paper describes the synthesis of protein microtube motors having a urease interior surface and highlights their nonbubble‐propelled behavior driven by enzymatic reaction (urea→NH3 and CO2). The precursor microtubes were prepared by layer‐by‐layer assembly using a track‐etched microporous polycarbonate membrane. Immobilization of a urease on the internal wall was accomplished using avidin–biotin interaction. The tubules swam smoothly in an aqueous media containing a physiological concentration of urea. Each tubule was rotating laterally while moving forward. It is remarkable that the microtubes were digested completely by proteases, demonstrating perfect biodegradability.  相似文献   
40.
A highly sensitive determination method was established for catecholamines (norepinephrine (NE), epinephrine, and dopamine) with high-performance liquid chromatography-peroxyoxalate chemiluminescence reaction detection. In this study, the method was applied to mouse plasma, and it was determined that only 10 μl of mouse plasma was necessary for the selective and reproducible determination of catecholamines. Studies were then conducted in acute cardiovascular effects of sodium nitroprusside, nicardipine, captopril (angiotensin-converting enzyme (ACE) inhibitor), candesartan, and olmesartan (type 1 angiotensin receptor antagonists (AT1 antagonists)) by this method. Sodium nitroprusside and nicardipine elevated plasma NE concentrations significantly, whereas the ACE inhibitor and the AT1 antagonists did not change plasma NE concentrations in anesthetized mice. These results suggested that angiotensin II-induced augmentation may be mainly carried through the central baroreflex pathway.  相似文献   
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