1,741 research outputs found
Development and characterization of scaffolds for 3D cell culture
No full textIn recent years the study of three-dimensional (3D) cell culture has undergone a progressive development. The 3D models have shown characteristics more similar to the overall conditions in vivo with respect to 2D cultures (Hutmacher DW., 2001). The 3D approach decreases the gap between cell culture system and the cellular physiology, helping to understand better various cell functions such as proliferation, adhesion, viability, morphology, microenvironment, and response to drugs. Compared to 2D cultivation, the cells in 3D are completely different in terms of morphology, signaling, and microenvironmental metabolism (Astashkina A et al., 2014). The scaffold provides the support necessary for the cells to attach, proliferate, and maintain their differentiated function. As a drawback, the structural characteristics of 3D scaffolds make their characterization quite complex.
In my project a new hydrogel scaffold (HS) has been produced and several methods have been modified and/or developed for characterizing its cell compatibility, porosity, mechanical and optical properties and molecular diffusion.
The first condition that has been verified was that the absence of toxicity for the cell types used and the capacity of the scaffolds to promote cell adhesion and growth for a period suitable for biological tests.
Different cell lines have been evaluated, like human endothelial vascular cell line (HECV), human keratinocyte cell line (NCTC), human fibroblast cell line and human liver carcinoma cell line. HECV and NCTC have been cultured in 3D for more than 30 days.
The porosity of the lyophilized scaffold has been calculated by liquid displacement method, using acetonitrile as the displacement liquid, and resulted to be higher than 95%.
The mechanical properties of the HS have been analysed and Young’s Modulus (YM) and yield strength (YS) were evaluated in dried state and in liquid immersion. The YM of HS ranges from 15 to 120 kPa, and the YS ranges from 3 to 21 kPa.
The transparency of HS has been easily evaluated by UV-VIS transmittance study and by observing letters printed on a paper sheet placed under the scaffold completely immersed in PBS, measuring the sharpness of the typographical sign, with respect to a reference read through a PBS solution.
The molecular diffusion through the scaffold has been evaluated using Franz diffusion cells at 37 °C, with metformin hydrochloride as diffusing molecule. The diffusion coefficient D was calculated, its value being approx. 1.2×10-9 m2/s
Author's reply to comment on ""Biological removal of polychlorinated dibenzo-p-dioxins from incinerator fly ash by sphingomonas wittichii RW1"" by Rolf U. Halden
No full textX111sciescopu
Spatial variation of scale effects of specific sediment yield in Zhujiang (Pearl River) basin
No full textThe scale effects of Area-Specific sediment yield (Ys) are studied for Zhujiang basin and its four sub-basins. Considering the entire Zhujiang basin, there is no apparent relation between Ys and contributing area (A(d)) for stations when A(d) is less than 100,000 km(2), while there is an upper envelope outline of Ys. For the stations with A(d) larger than 100,000 km(2) mainly located on the middle and lower reaches, there is a negative relation of Ys to A(d). Considering the four sub-basins of Zhujiang basin, three kinds of relations between Ys and A(d) are established: (1) Ys increases with A(d) for the sub-basin of the upper reach; (2) Ys increases with A(d) then declines for the two sub-basins of the middle reaches; (3) Ys decreases with Ad for the sub-basin of the lower reaches. The Ys-A(d) relation is further investigated using the spatial variation of hill slopes, the Land Use and Land Cover (LULC), and the bed slopes. Finally, to remove the effect of A(d) and to make Ys comparable across scales, the scaled Ys calculation equations are given for both linear and non-linear relations between Ys and A(d) first. And then the Ys are scaled to the standard units of 1000 km(2)and 10,000 km(2). Using Kriging method, the Ys maps are created under GIS platform where high Ys centers are outlined, and the spatial patterns of Ys are compared for the two standard unit Ys maps. (C) 2013 Elsevier Ltd and INQUA. All rights reserved
FOURIER TRANSFORM MICROWAVE SPECTROSCOPY OF SCS (X), YS (X) AND VS (X)
No full textAuthor Institution: Department of Chemistry and Steward Observatory, University of Arizona, Tucson, AZ 85721Pure rotational spectra of three transition-metal monosulfides, ScS, YS, and VS, have been recorded using Fourier transform microwave spectroscopy (FTWM) in the range 10-40 GHz. These molecules are all free radicals and have been synthesized in a mixture of HS gas with metal vapor, obtained by laser ablation of a metal rod. In the case of ScS and VS, a discharge was necessary to successfully produce the molecules. For YS, the N=10, 21, 32 and 43 rotational transitions have been recorded. For ScS and VS, the N=10, N=21 and N=32 have been obtained. Vanadium, scandium and yttrium hyperfine structures were resolved for these species. Rotational, fine structure and hyperfine coupling constants have been determined for all three radicals. This works completes the high-resolution pure rotational measurements of 3d transition-metal monosulfides, and provides the most accurate values of the hyperfine parameters for these molecules to date. Bond lengths and spectroscopic parameters will be presented
Application of blockchain technology in the shipping industry
No full textAuthor name used in this publication: 鄢然Author name used in this publication: 王帅安Author name used in this publication: 周煜圣Title in simplified Chinese: 区块链技术在航运业的应用综述202306 bcwwVersion of RecordOthersNational Natural Science Foundation of China;PublishedVoR allowe
The Daily Menu of Miners’ Families of Donbass in 1965 – 1985 ys
No full textУ статті розглядається повсякденне харчування шахтарських родин Донбасу у 1965 – 1985 роках. Автор
акцентує увагу на особливих традиціях організації харчування у шахтарських родинах порівняно з іншими
типами сімей. Дослідження базується на неопублікованих архівних документах, статистичних даних та
матеріалах усної історії.В статье рассматривается повседневное питание шахтерских семей Донбасса в 1965 – 1985 годах. Автор
акцентирует внимание на особенных традициях организации питания в шахтерских семьях по сравнению
с другими типами семей. Исследование базируется на неопубликованных архивных документах, статисти-
ческих данных и материалах устной истории.Questions of a food and consumption of foodstuffs are studied insufficiently carefully in modern historical
science. But it’s one of the basic indicators of standard of well-being of the population. The author describes and
characterizes the most popular and favorite dishes in miners’ families, and the traditions of behaviour at the
table. In addition, the special attention is received to dependence of food from the standard of financial support
of miners’ families, and also from specificity of a miner’s trade. The author also focuses attention on special
traditions of meals in miners’ families as compared with other types of families, and notices negative tendencies
in a daily food, such as regular use of alcoholic beverages. The research is based on the unpublished archive
documents, the statistical data and materials of verbal history. The article is a part of more wider research
devoted to daily life of miners’ families of Donbass in 1965 – 1985 ys
Optimal design of simulation experiments with nearly saturated queues
Full text linkSimulation Models;Interpolation;Queueing Network;Extrapolation
The Daily Menu of Miners’ Families of Donbass in 1965 – 1985 ys
No full textУ статті розглядається повсякденне харчування шахтарських родин Донбасу у 1965 – 1985 роках. Автор
акцентує увагу на особливих традиціях організації харчування у шахтарських родинах порівняно з іншими
типами сімей. Дослідження базується на неопублікованих архівних документах, статистичних даних та
матеріалах усної історії.В статье рассматривается повседневное питание шахтерских семей Донбасса в 1965 – 1985 годах. Автор
акцентирует внимание на особенных традициях организации питания в шахтерских семьях по сравнению
с другими типами семей. Исследование базируется на неопубликованных архивных документах, статисти-
ческих данных и материалах устной истории.Questions of a food and consumption of foodstuffs are studied insufficiently carefully in modern historical
science. But it’s one of the basic indicators of standard of well-being of the population. The author describes and
characterizes the most popular and favorite dishes in miners’ families, and the traditions of behaviour at the
table. In addition, the special attention is received to dependence of food from the standard of financial support
of miners’ families, and also from specificity of a miner’s trade. The author also focuses attention on special
traditions of meals in miners’ families as compared with other types of families, and notices negative tendencies
in a daily food, such as regular use of alcoholic beverages. The research is based on the unpublished archive
documents, the statistical data and materials of verbal history. The article is a part of more wider research
devoted to daily life of miners’ families of Donbass in 1965 – 1985 ys
The fatigue life estimation of notched specimens under random loading
Full text linkThe LY12-cz aluminium alloy sheet specimens with a central hole were tested under constant amplitude loading, Rayleigh narrow band random loading and a typical fighter broad band random loading. The fatigue life was estimated by means of the nominal stress and the Miner's rule. The stress cycles were distinguished by the rainflow count, range count and peak value count, respectively. The comparison between the estimated results and the test results was made. The effects of random loading sequence and small load cycles on fatigue life were also studied
- …
