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421.
Semiconductor Nanowires: Tunable Quantum Confinement in Ultrathin,Optically Active Semiconductor Nanowires Via Reverse‐Reaction Growth (Adv. Mater. 13/2015) 下载免费PDF全文
422.
Esra Altun Mehmet Onur Aydogdu Fatma Koc Maryam Crabbe‐Mann Francis Brako Rupy Kaur‐Matharu Gunes Ozen Serap Erdem Kuruca Ursula Edirisinghe Oguzhan Gunduz Mohan Edirisinghe 《大分子材料与工程》2018,303(3)
Bacterial cellulose (BC) is a very promising biological material. However, at present its utilization is limited by difficulties in shape forming it. In this Communication, it is shown how this can be overcome by blending it with poly(methylmethacrylate) (PMMA) polymer. BC:PMMA fibers are produced by pressurized gyration of blended BC:PMMA solutions. Subsequently, BC:PMMA bandage‐like scaffolds are generated with different blends. The products are investigated to determine their morphological and chemical features. Cell culture and proliferation tests are performed to obtain information on biocompatibility of the scaffolds. 相似文献
423.
Kiichi Suzuki Masato Kato Takeo Sunaoshi Hiroki Uno Ursula Carvajal-Nunez Andrew T. Nelson Kenneth J. McClellan 《Journal of the American Ceramic Society》2019,102(4):1994-2008
The thermal and mechanical properties of cerium dioxide (CeO2) were assessed using a range of experimental techniques. The oxygen potential of CeO2 was measured by the thermogravimetric technique, and a numerical fit for the oxygen potential of CeO2 is derived based on defect chemistry. Mechanical properties of CeO2 were obtained using sound velocity measurement, resonant ultrasound spectroscopy and nanoindentation. The obtained mechanical properties of CeO2 are then used to evaluate the Debye temperature and Grüneisen constant. The heat capacity and thermal conductivity of CeO2 were also calculated using the Debye temperature and the Grüneisen constant. Finally, the thermal conductivity was calculated based upon laser flash analysis measurements performed on pellets fabricated using a range of feedstock purities to resolve discrepancies in the existing literature. 相似文献
424.
Xuan Hoan Vu Ursula Bentrup Michael Hunger Ralph Kraehnert Udo Armbruster Andreas Martin 《Journal of Materials Science》2014,49(16):5676-5689
Nanosized-ZSM-5/SBA-15 analog composites (ZSC) were successfully synthesized in a two-step process from zeolite seed solutions containing intact ZSM-5 nanocrystals (nano-ZSM-5) by high-temperature synthesis in mild acidic media (200 °C, pH 3.5). The ZSC solids exhibit domains of nano-ZSM-5 blended homogeneously with highly condensed, well-ordered mesoporous SBA-15 analogs containing zeolite building units. The content of nano-ZSM-5 phase and SBA-15 analog phase can be controlled by a single synthesis parameter, i.e., the precrystallization time of the initially formed zeolite seed solution. Compared to conventional Al-SBA-15, the acidic properties, particularly the surface density of strong Brønsted acid sites, of the ZSC are significantly improved while its micro-/mesostructures are well maintained even upon steaming at 800 °C for 24 h. The catalytic activity of the ZSC solids compared to that of commercial ZSM-5 and Al-SBA-15 samples was evaluated in the gas phase cracking of cumene and 1,3,5-tri-isopropylbenzene (TIPB) as probe reactions. The results show that the ZSC materials are effective for the conversion of both cumene and TIPB due to the increased density of the Brønsted acid sites with high accessibility provided by well-dispersed nano-ZSM-5 in the mesoporous SBA-15 analog matrix. 相似文献
425.
Ursula R. Kattner 《Journal of Phase Equilibria and Diffusion》2013,34(6):437-437
426.
Nicola Erdsack Guido Dehnhardt Martin Witt Andreas Wree Ursula Siebert Wolf Hanke 《Journal of the Royal Society Interface》2015,12(104)
Vertebrate surface structures, including mammalian skin and hair structures, have undergone various modifications during evolution in accordance with functional specializations. Harbour seals rely on their vibrissal system for orientation and foraging. To maintain tactile sensitivity even at low temperatures, the vibrissal follicles are heated up intensely, which could cause severe heat loss to the environment. We analysed skin samples of different body parts of harbour seals, and expected to see higher hair densities at the vibrissal pads as a way to reduce heat loss. In addition to significantly higher hair densities around the vibrissae than on the rest of the body, we show a unique fur structure of hair bundles consisting of broad guard hairs along with hairs of a new type, smaller than guard hairs but broader than underhairs, which we defined as ‘intermediate hairs’. This fur composition has not been reported for any mammal so far and may serve for thermal insulation as well as drag reduction. Furthermore, we describe a scale-like skin structure that also presumably plays a role in drag reduction. 相似文献
427.
Alejandro Majali-Martinez Ursula Weiss-Fuchs Heidi Miedl Desiree Forstner Julia Bandres-Meriz Denise Hoch Josip Djelmis Marina Ivanisevic Ursula Hiden Martin Gauster Gernot Desoye 《International journal of molecular sciences》2021,22(20)
Type 1 diabetes mellitus (T1DM) is associated with reduced fetal growth in early pregnancy, but a contributing role of the placenta has remained elusive. Thus, we investigated whether T1DM alters placental development in the first trimester. Using a protein array, the level of 60 cell-cycle-related proteins was determined in human first trimester placental tissue (gestational week 5–11) from control (n = 11) and T1DM pregnancies (n = 12). Primary trophoblasts (gestational week 7–12, n = 32) were incubated in the absence (control) or presence of hyperglycemia (25 mM D-glucose) and hyperosmolarity (5.5 mM D-glucose + 19.5 mM D-mannitol). We quantified the number of viable and dead trophoblasts (CASY Counter) and assessed cell cycle distribution (FACS) and trophoblast invasion using a transwell assay. T1DM was associated with a significant (p < 0.05) downregulation of Ki67 (−26%), chk1 (−25%), and p73 (−26%). The number of viable trophoblasts was reduced under hyperglycemia (−23%) and hyperosmolarity (−18%), whereas trophoblast invasion was increased only under hyperglycemia (+6%). Trophoblast cell death and cell cycle distribution remained unaffected. Collectively, our data demonstrate that hyperglycemia decreases trophoblast proliferation as a potential contributing factor to the reduced placental growth in T1DM in vivo. 相似文献
428.
Maia Segura-Wang Bertrand Grenier Suzana Ilic Ursula Ruczizka Maximiliane Dippel Moritz Bünger Matthias Hackl Veronika Nagl 《International journal of molecular sciences》2021,22(21)
Deoxynivalenol (DON), a frequent mycotoxin worldwide, impairs human and animal health. The response of microRNAs, small non-coding RNAs, to DON has been scarcely investigated, but holds remarkable potential for biomarker applications. Hence, we aimed to investigate DON-induced changes in the microRNA expression in porcine liver, jejunum and serum by combining targeted and untargeted analyses. Piglets received uncontaminated feed or feed containing 900 µg/kg and 2500 µg/kg DON for four weeks, followed by a wash-out period. In tissue, only slight changes in microRNA expression were detected, with ssc-miR-10b being downregulated in liver of DON-exposed piglets. In serum, several microRNAs were differentially expressed upon DON exposure, four of which were validated by qPCR (ssc-miR-16, ssc-miR-128, ssc-miR-451, ssc-miR-205). The serum microRNA response to DON increased over time and declined after removal of contaminated diets. Receiver operating curve analyses for individual microRNAs were significant, and a combination of the four microRNAs increased the predictive capacity for DON exposure. Predicted microRNA target genes showed enrichment of several pathways including PIK3-AKT, Wnt/β-catenin, and adherens junctions. This study gives, for the first time, a comprehensive view of the porcine microRNA response to DON, providing a basis for future research on microRNAs as biomarkers for mycotoxins. 相似文献
429.
A fractal texture analysis technique was applied to bread crumb digital images. Fractal dimensions obtained from several methods
(fractional Brownian motion, frequency domain, relative differential box-counting, morphological fractal, mass fractal and
random walks methods) were investigated in order to determine their capability to accurately describe the surface roughness
of bread crumb images or the visual appearance of bread crumb in meaningful terms. A total of 500 bread crumb images of different
porosity and grain quality were analysed. It was found that bread crumb appearance could be effectively quantified by the
fractal dimension of its digital image. Correlations of fractal dimensions with mean cell area, standard deviation of cell
area and void fraction were variable for the fractal methods. While the mass fractal method measured better crumb heterogeneity,
other methods quantified coarseness, cell–cell wall ruggedness and cell wall tortuosity. A vector comprising fractal dimensions
would objectively depict crumb grain and would allow comparisons between different bread crumb images. 相似文献
430.
Riana Jordão Barrozo Heinemann Jorge Herman Behrens & Ursula Maria Lanfer-Marquez 《International Journal of Food Science & Technology》2006,41(6):627-634
Despite nutritional claims and other advantages that parboiled rice possesses, its consumption is still low in Brazil mainly because of the local preference for milled rice. In the first part of this study, the acceptability of five commercial brands of parboiled and milled rice was assessed by 100 consumers and similar acceptance levels were observed, evidencing that consumers might not reject parboiled rice for its sensory properties. In the second part, 286 consumers were surveyed about their eating habits and attitude towards rice, focusing especially the nutritional value, sensory and convenience aspects of parboiled rice. In the survey 35% of the respondents were unaware of parboiled rice. Cluster analysis performed on data grouped consumers in one segment with positive attitude and in two other segments with negative attitude towards parboiled rice. Segmentation was mainly because of negative beliefs about the sensory characteristics of the product, although its nutritional claims were unknown to most respondents, revealing the need of marketing efforts focused on informing consumers the health benefits and convenience of eating parboiled rice. 相似文献