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排序方式: 共有413条查询结果,搜索用时 46 毫秒
381.
Giulia Torrieri Imran Iqbal Flavia Fontana Virpi Talman Heidi Liljenbäck Andriana Putri Wail Nammas Johan Rajander Xiang Guo-Li Philip S. Low Tambet Teesalu Anne Roivainen Jouni Hirvonen Heikki Ruskoaho Vimalkumar Balasubramanian Antti Saraste Hélder A. Santos 《Advanced functional materials》2023,33(34):2303658
Myocardial infarction (MI) is the leading cause of death worldwide. However, current therapies are unable to restore the function of the injured myocardium. Advanced approaches, such as stimulation of cardiomyocyte (CM) proliferation are promising, but suffer from poor pharmacokinetics and possible systemic adverse effects. Nanomedicines can be a solution to the above-mentioned drawbacks. However, targeting the cardiac tissue still represents a challenge. Herein, a MI-selective precision nanosystem is developed, that relies on the heart targeting properties of atrial natriuretic peptide (ANP) and lin-TT1 peptide-mediated hitchhiking on M2-like macrophages. The system based on pH-responsive putrescine-modified acetalated dextran (Putre-AcDEX) nanoparticles, shows biocompatibility with cultured cardiac cells, and ANP receptor-dependent interaction with CMs. Moreover, treatment with nanoparticles (NPs) loaded with two pleiotropic cellular self-renewal promoting compounds, CHIR99021 and SB203580, induces a 4-fold increase in bromodeoxyuridine (BrdU) incorporation in primary cardiomyocytes compared to control. In vivo studies confirm that M2-like macrophages targeting by lin-TT1 peptide enhances the heart targeting of ANP. In addition, NP administration does not alter the immunological profile of blood and spleen, showing the short-term safety of the developed system in vivo. Overall, the study results in the development of a peptide-guided precision nanosystem for delivery of therapeutic compounds to the infarcted heart. 相似文献
382.
Noora Ristolainen Ulla Hippi Jukka Seppl Antti Nyknen Janne Ruokolainen 《Polymer Engineering and Science》2005,45(12):1568-1575
Montmorillonite is a promising substitute for aluminum trihydroxide in flame‐retardant polypropylene/aluminum trihydroxide (PP/ATH) composites. Study was made of the partial substitution of organoclay for ATH in PP/ATH composites. The total concentration of filler was kept at 30 wt%. The composites were compatibilized with two types of compatibilizer: commercial maleic anhydride functionalized polypropylene (PP‐g‐MA) and hydroxyl‐functionalized polypropylene (PP‐co‐OH) prepared with metallocene catalyst. The effect of compatibilization on the morphology was studied by the transmission electron microscopy and the scanning electron microscopy. Mechanical properties were characterized by tensile and impact measurements, and flammability properties with a cone calorimeter. Addition of compatibilizer and stearic acid (SA) treatment of the ATH particles contributed to the dispersion of the fillers. Both compatibilizers produced organoclay with exfoliated structure and improved adhesion between the fillers and the matrix. Toughness improved and decomposition and flammability were reduced. POLYM. ENG. SCI. 45:1568–1575, 2005. © 2005 Society of Plastics Engineers 相似文献
383.
Veli-Matti Tiainen Antti Soininen Esa Alakoski Yrjö T. Konttinen 《Diamond and Related Materials》2008,17(12):2071-2074
With filtered pulsed arc discharge (FPAD) method it is possible to achieve very high adhesion of high quality diamond-like carbon (DLC). Here we explain this high adhesion with the oxide reduction and consequent carbide formation and ion mixing of the substrate when exposed to high temperature carbon plasma ions. The use of intensive high energy (> 2 keV) carbon plasma is the only practical method to achieve ultimate adhesion of DLC. With this unique method presented, the adhesion properties and the substrate interface electron spectroscopy for chemical analysis (ESCA) spectra of DLC coatings are independent of the pre-treatment of silicon substrates. High adhesion and proper selection of substrate enables to deposit thick DLC coatings (> 10 μm). We also show how the DLC deposition system can be improved and simplified. 相似文献
384.
Hakkarainen T Schramm A Tukiainen A Ahorinta R Toikkanen L Guina M 《Nanoscale research letters》2010,5(12):1892-1896
We report the use of partially relaxed tensile as well as compressively strained GaInP layers for lateral ordering of InAs
quantum dots with the aid of misfit dislocation networks. The strained layers and the InAs QDs were characterized by means
of atomic force microscopy, scanning electron microscopy, and X-ray reciprocal space mapping. The QD-ordering properties of
compressive GaInP are found to be very similar with respect to the use of compressive GaInAs, while a significantly stronger
ordering of QDs was observed on tensile GaInP. Furthermore, we observed a change of the major type of dislocation in GaInP
layers as the growth temperature was modified. 相似文献
385.
386.
Heli Jantunen Risto Rautioaho Antti Uusimäki Seppo Leppävuori 《Journal of the American Ceramic Society》2000,83(11):2855-2857
A low-temperature cofired ceramic (LTCC) composition for radio-frequency purposes was accomplished without prior glass preparation. In this process, the formulation was made by mixing the glass-forming oxides (ZnO, SiO2 , and B2 O3 ) with the commercial microwave ceramic MgTiO3 –CaTiO3 . The sintering, microstructure, and microwave properties were compared to a formulation with exactly the same composition, but a conventional production route, including glass preparation. The novel preparation route resulted in improved firing properties of the mixture. Also, the densities, porosities, and phases of the samples were almost the same as those of the conventional samples, but the phase fractions were different. Finally, this preparation route produced better dielectric values. 相似文献
387.
Koikkalainen J Tölli T Lauerma K Antila K Mattila E Lilja M Lötjönen J 《IEEE transactions on medical imaging》2008,27(11):1643-1654
388.
Kimmo Kaunisto Heidi Vahasalo Vladimir Chukharev Nikolai V. Tkachenko Paola Vivo Marja Niemi Antti Tolkki Alexander Efimov Helge Lemmetyinen 《Thin solid films》2009,517(9):2988-21049
Efficient photoinduced interlayer electron transfer from a phthalocyanine derivative, ZnPH4, to porphyrin cation of a porphyrin-fullerene donor-acceptor dyad was demonstrated by using time-resolved photovoltage technique. Multicomponent thin films with desired layer arrangements were constructed by the Langmuir-Blodgett and spin-coating methods in order to study charge transfer in solid state. As a contradiction to the photovoltage experiments, the dyad monolayer in the film structure did not enhance the current amplitude in electrochemical photocurrent measurements. This is associated with a weak electronic interaction between fullerene and aqueous electrolyte, reducing the photocurrent generation. The use of poly(3-hexylthiophene) as a hole conducting layer was shown to improve photocurrent yield of the device by forming efficient heterojunction together with the ZnPH4 layer. 相似文献
389.
We study theoretically the light-scattering efficiency of paper coatings made of starch acetate pigments. For the light-scattering code we use a discrete dipole approximation method. The coating layer is assumed to consists of roughly equal-sized spherical pigments packed either at a packing density of 50% (large cylindrical slabs) or at 37% or 57% (large spheres). Because the scanning electron microscope images of starch acetate samples show either a particulate or a porous structure, we model the coatings in two complementary ways. The material can be either inside the constituent spheres (particulate case) or outside of those (cheeselike, porous medium). For the packing of our spheres we use either a simulated annealing or a dropping code. We can estimate, among other things, that the ideal sphere diameter is in the range 0.25-0.4 microm. 相似文献
390.
Antti H. Niemi 《International journal for numerical methods in engineering》2010,81(4):485-512
A four‐node shell finite element of arbitrary quadrilateral shape is developed and applied to the solution of static and vibration problems. The element incorporates five generalized degrees of freedom per node, namely the three displacements of the curved middle surface and the two rotations of its normal vector. The stiffness properties of the element are defined using isoparametric principles in a local co‐ordinate system with axes approximately parallel to the edges of the element. The formulation is based on a modern, refined variant of the shallow shell models found from the classical books on shell theory. In addition, the bending behavior of the element is improved with numerical modifications, which include mixed interpolation of the membrane and transverse shear strains. The numerical experiments show that the element is able to compete in accuracy with the highly reputable bilinear elements of the commercial codes ABAQUS and ADINA. The new formulation even outperforms its commercial rivals in problems with strong layers such as vibration problems or problems with concentrated loads. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献