104 research outputs found
ОБРАЗОВАНИЕ ЧАСТИЦ «ЧЕРНОГО» ЗОЛОТА ПРИ ЛАЗЕРНОЙ АБЛЯЦИИ НАНОСЕКУНДНЫМ ИЗЛУЧЕНИЕМ ЧЕТВЕРТОЙ ГАРМОНИКИ YAG:ND-ЛАЗЕРА
The research results of UV 266 nm gold ablation are presented. It is shown that the deposit structure on the surface around ablation pits sharply depends on a pit depth. As the pit depth is increased, gold micro- and nanoparticles acquire a more developed surface structure and the surface around the pits gets deep black color – “black” gold appears. Some features and possible mechanisms of forming “black” gold structures at ablation over the 266 nm powerful nanosecond laser radiation range are also considered.Представлены результаты исследования абляции золота УФ-излучением 266 нм. Показано, что структура депозита на поверхности вокруг абляционных лунок зависит от их глубины. При увеличении глубины лунки осажденные микро- и наночастицы золота приобретают более развитую поверхностную структуру, при этом поверхность вокруг лунок становится насыщенного черного цвета – появляется «черное» золото. Также рассмотрены некоторые особенности и возможные механизмы формирования структур «черного» золота при абляции мощным наносекундным лазерным излучением с длиной волны 266 нм
SPEAR: The Next Generation GFDL Modeling System for Seasonal to Multidecadal Prediction and Projection
We document the development and simulation characteristics of the next generation modeling system for seasonal to decadal prediction and projection at the Geophysical Fluid Dynamics Laboratory (GFDL). SPEAR (Seamless System for Prediction and EArth System Research) is built from component models recently developed at GFDL—the AM4 atmosphere model, MOM6 ocean code, LM4 land model, and SIS2 sea ice model. The SPEAR models are specifically designed with attributes needed for a prediction model for seasonal to decadal time scales, including the ability to run large ensembles of simulations with available computational resources. For computational speed SPEAR uses a coarse ocean resolution of approximately 1.0° (with tropical refinement). SPEAR can use differing atmospheric horizontal resolutions ranging from 1° to 0.25°. The higher atmospheric resolution facilitates improved simulation of regional climate and extremes. SPEAR is built from the same components as the GFDL CM4 and ESM4 models but with design choices geared toward seasonal to multidecadal physical climate prediction and projection. We document simulation characteristics for the time mean climate, aspects of internal variability, and the response to both idealized and realistic radiative forcing change. We describe in greater detail one focus of the model development process that was motivated by the importance of the Southern Ocean to the global climate system. We present sensitivity tests that document the influence of the Antarctic surface heat budget on Southern Ocean ventilation and deep global ocean circulation. These findings were also useful in the development processes for the GFDL CM4 and ESM4 models
ОЦЕНКА ЭФФЕКТИВНОГО КОЭФФИЦИЕНТА ПОГЛОЩЕНИЯ РОГОВИЦЫ ГЛАЗА НА ДЛИНЕ ВОЛНЫ 213 НМ ИЗ АБЛЯЦИОННЫХ ИЗМЕРЕНИЙ
It is shown experimentally that a cornea represents a 213 nm UV inhomogeneous material both at depth and around a surface in relation to UV effective absorption coefficient and local laser depth ablation rate, which should be taken into account for a more exact planning of a profile of removed cornea collagen material during eye vision correction. Экспериментально показано, что роговица глаза для УФ-излучения (213 нм) представляет собой неоднородный материал как по глубине, так и вдоль поверхности, в отношении эффективного коэффициента поглощения и локальной скорости абляционного удаления материала роговицы, что необходимо учитывать для более точного планирования профиля удаляемого коллагена роговицы при операциях коррекции зрения.
Raw-appearing Restructured fish models made with Sodium alginate or Microbial transglutaminase and effect of chilled storage
Myeloperoxidase modulates human platelet aggregation via actin cytoskeleton reorganization and store-operated calcium entry
Summary
Myeloperoxidase (MPO) is a heme-containing enzyme released from activated leukocytes into the extracellular space during inflammation. Its main function is the production of hypohalous acids that are potent oxidants. MPO can also modulate cell signaling and inflammatory responses independently of its enzymatic activity. Because MPO is regarded as an important risk factor for cardiovascular diseases associated with increased platelet activity, we studied the effects of MPO on human platelet functional properties. Laser scanning confocal microscopy was used to reveal carbohydrate-independent MPO binding to human platelet membrane. Adding MPO to platelets did not activate their aggregation under basal conditions (without agonist). In contrast, MPO augmented agonist-induced platelet aggregation, which was not prevented by MPO enzymatic activity inhibitors. It was found that exposure of platelets to MPO leads to actin cytoskeleton reorganization and an increase in their elasticity. Furthermore, MPO evoked a rise in cytosolic Ca2+ through enhancement of store-operated Ca2+ entry (SOCE). Together, these findings indicate that MPO is not a direct agonist but rather a mediator that binds to human platelets, induces actin cytoskeleton reorganization and affects the mechanical stiffness of human platelets, resulting in potentiating SOCE and agonist-induced human platelet aggregation. Therefore, an increased activity of platelets in vascular disease can, at least partly, be provided by MPO elevated concentrations
Chromium-containing organometallic self-organized materials for nanophotonics
Novel non-linear optical polymeric film-producing nanocomposites based on bis(arene)chromium complexes incorporated into CN-containing matrices have been developed. Measurements by the spectrally resolved two-beam coupling method with a femtosecond range of pulse widths (central wavelength 795-800 nm) confirmed that the test composites exhibited a significant cubic nonlinear optical susceptibility of the ultra-fast electronic type. An open aperture Z-scan of the polymer film at 1550 nm showed a value of 9 × 10¿19 cm3 W¿2 for the three-photon absorption coefficient. The electro-optical measurements of the polymer composite showed a high electro-optical response (r33.n3 = 4.245 pm V¿1 at modulation frequency 210 Hz and poling DC voltage 2.16 V). A significant enhancement of the signals with a decrease in modulation frequency was observed consistent with an essential contribution of orientation effects to the electro-optical response. The measurements in the absence of external electrical fields showed a natural anisotropy resulting from self-organization taking place during the film formation process as confirmed by electron diffraction studies. A single Cr-C distance was found in the EXAFS data refinement, showing that the arene rings are parallel and symmetric as in bis(benzene) chromium
Synthetic, structural, and spectroscopic studies of sterically crowded tin-chalcogen acenaphthenes
The work in this project was supported by the Engineering and Physical Sciences Research Council (EPSRC) and EaStCHEM.A series of sterically encumbered peri-substituted acenaphthenes have been prepared containing chalcogen and tin moieties at the close 5,6-positions (Acenap[SnPh3][ER], Acenap = acenaphthene-5,6-diyl, ER = SPh (1), SePh (2), TePh (3), SEt (4); Acenap[SnPh2Cl][EPh], E = S (5), Se (6); Acenap[SnBu2Cl][ER], ER = SPh(7), SePh (8), SEt (9)). Two geminally bis(peri-substituted) derivatives ({Acenap[SPh2]}2SnX2, X = Cl (10), Ph (11)) have also been prepared, along with the bromo–sulfur derivative Acenap(Br)(SEt) (15). All 11 chalcogen–tin compounds align a Sn–CPh/Sn–Cl bond along the mean acenaphthene plane and position a chalcogen lone pair in close proximity to the electropositive tin center, promoting the formation of a weakly attractive intramolecular donor–acceptor E···Sn–CPh/E···Sn–Cl 3c-4e type interaction. The extent of E→Sn bonding was investigated by X-ray crystallography and solution-state NMR and was found to be more prevalent in triorganotin chlorides 5–9 in comparison with triphenyltin derivatives 1–4. The increased Lewis acidity of the tin center resulting from coordination of a highly electronegative chlorine atom was found to greatly enhance the lp(E)−σ*(Sn–Y) donor–acceptor 3c-4e type interaction, with substantially shorter E–Sn peri distances observed in the solid state for triorganotin chlorides 5–9 (∼75% ∑rvdW) and significant 1J(119Sn,77Se) spin–spin coupling constants (SSCCs) observed for 6 (163 Hz) and 8 (143 Hz) in comparison to that for the triphenyltin derivative 2 (68 Hz). Similar observations were observed for geminally bis(peri-substituted) derivatives 10 and 11.PostprintPeer reviewe
PREDICTION OF THE QUALITY OF SOME TURKISH WHEAT GENOTYPES BY ELECTROPHORETIC SEPARATION OF PROTEIN FRACTIONS
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