scholarly journals Cationic Fluorescent Nanogel Thermometers based on Thermoresponsive Poly(N-isopropylacrylamide) and Environment-Sensitive Benzofurazan

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1305 ◽  
Author(s):  
Teruyuki Hayashi ◽  
Kyoko Kawamoto ◽  
Noriko Inada ◽  
Seiichi Uchiyama
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Change ◽  
Culture Medium ◽  
Fluorescence Enhancement ◽  
Carcinoma Cells ◽  
Temperature Dependent ◽  
Medium Temperature ◽  
Mild Conditions ◽  
Transmission Electron

Cationic nanogels of N-isopropylacrylamide (NIPAM), including NIPAM-based cationic fluorescent nanogel thermometers, were synthesized with a cationic radical initiator previously developed in our laboratory. These cationic nanogels were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential measurements and fluorescence spectroscopy, as summarized in the temperature-dependent fluorescence response based on the structural change in polyNIPAM units in aqueous solutions. Cellular experiments using HeLa (human epithelial carcinoma) cells demonstrated that NIPAM-based cationic fluorescent nanogel thermometers can spontaneously enter the cells under mild conditions (at 25 °C for 20 min) and can show significant fluorescence enhancement without cytotoxicity with increasing culture medium temperature. The combination of the ability to enter cells and non-cytotoxicity is the most important advantage of cationic fluorescent nanogel thermometers compared with other types of fluorescent polymeric thermometers, i.e., anionic nanogel thermometers and cationic/anionic linear polymeric thermometers.

scholarly journals Encapsulation of Fullerenes: A Versatile Approach for the Confinement and Release of Materials Within Open-Ended Multiwalled Carbon Nanotubes

2021 ◽  
Vol 9 ◽  
Author(s):  
Stefania Sandoval ◽  
Gerard Tobias
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Inorganic Material ◽  
Single Step ◽  
The Other ◽  
Multiwalled Carbon ◽  
Mild Conditions ◽  
Transmission Electron

We have employed fullerenes as versatile agents to “cork” the open tips of multiwalled carbon nanotubes (MWCNTs), and as promoting species for the release of the inorganic material filled within the nanotubes’ cavities. High Z element compounds, namely, PbI2, ZnI2, and CeI3, were chosen to easily determine the presence of the filler inside the hosting nanotubes by transmission electron microscopy (TEM). Fullerenes can isolate inorganic nanostructures confined within the hollow cavities of MWCNTs, which allows the removal of the external material remnant after the filling. Otherwise, taking advantage of the affinity of fullerenes with selected solvents, we have confirmed the ability of the C60 molecules to promote the displacement of the inorganic guest from the host. We propose two different strategies to trigger the release, employing vapor and liquid phase treatments. The first protocol involves annealing filled MWCNTs in presence of fullerenes (to obtain C60PbI2@MWCNTs) and the subsequent washing of the sample in ethanol under mild conditions. On the other hand, the simultaneous introduction of the C60 molecules and the liberation of the guest are produced by a single step wet procedure; the latter being potentially useful when materials that are not stable at high temperatures are employed for filling.

scholarly journals In Situ Investigations on Stress and Microstructure Evolution in Polycrystalline Ti(C,N)/α-Al2O3 CVD Coatings under Thermal Cycling Loads

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 158
Author(s):  
José García ◽  
Maiara Moreno ◽  
Wei Wan ◽  
Daniel Apel ◽  
Haroldo Pinto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Cycling ◽  
Microstructure Evolution ◽  
Temperature Dependent ◽  
Alumina Layer ◽  
Stress Behavior ◽  
Transmission Electron ◽  
Α Al2o3

The stress behavior and the associated microstructure evolution of industrial Ti(C,N)/α-Al2O3 coatings subjected to thermal cycling are investigated by in situ energy dispersive synchrotron X-ray diffraction and transmission electron microscopy. Temperature-dependent stresses and changes in microstructural parameters (domain size and microstrain) are analyzed by in situ measurements at different temperatures between 25 and 800 °C, both in the heating up and cooling down step, including several thermal cycles. Transmission electron microscopy is used to evaluate defects before and after the thermal treatment. The introduction of high compressive stresses in α-Al2O3 by top-blasting is connected to a high defect density at the basal planes of the alumina layer. The stress relaxation of the alumina layer at high temperatures is associated with a successive annihilation of defects until a reversible temperature-dependent stress condition is set. Top-blasting does not change the initial microstructure and residual stress of the Ti(C,N) layer. Ti(C,N) shows a cyclic stress behavior associated with the heat treatment and an elastic deformation behavior in the temperature range investigated.

Scanning and Transmission Electron Microscopy of Isolated Cells of Hydra littoralis

1972 ◽  
Vol 30 ◽  
pp. 160-161 ◽  
Author(s):  
Jane A. Westfall ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Osmium Tetroxide ◽  
Culture Medium ◽  
Sensory Cells ◽  
Isolated Cells ◽  
Sem And Tem ◽  
Transmission Electron ◽  
Cacodylate Buffer ◽  
Calcium And Magnesium Ions

Using scanning and transmission electron microscopy (SEM and TEM), we observed batteries of 20-30 nematocytes, cnidoblasts, sensory cells, and other neurons invaginated within epitheliomuscular cells of Hydra. In an attempt to determine how the cells were structurally interrelated, we isolated cells of Hydra littoralis for further study by SEM and TEM.To isolate cells, 30 Hydra littoralis were placed for 30 minutes in a P19 culture medium modified by omitting calcium and magnesium ions, adding 20% sucrose and stabilizing at pH 7.2 with sodium phosphate, then pipetted gently to free the epithelial cells from the mesoglea. Glutaraldehyde was added to make a 5% solution and the cells were fixed 1 hour at 0-4°C, centrifuged 10 minutes at 1000 X g, resuspended in cacodylate buffer twice, and placed 2 hours in 4% osmium tetroxide at 0-4°C.

Synthesis of Nanoporous Rutile Nanocrystals under Mild Conditions

2015 ◽  
Vol 1721 ◽  
Author(s):  
Kairat Sabyrov ◽  
Virany M. Yuwono ◽  
R. Lee Penn
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Complex Structure ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Cryogenic Transmission Electron Microscopy ◽  
Mild Conditions ◽  
Transmission Electron ◽  
Oriented Aggregation

ABSTRACTSingle-crystalline rutile with porous and complex structure can be produced by tuning reaction conditions so as to maintain low titania solubility. X-ray diffraction, high-resolution transmission electron microscopy, and cryogenic transmission electron microscopy results are consistent with the hypothesis that oriented aggregation of anatase crystals precedes rutile nucleation and growth from anatase nanocrystal interfaces. The product rutile retains morphological and microstructure features consistent with an aggregation-based phase transformation because coarsening, or monomer-by-monomer growth, is suppressed under these conditions of low titania solubility.

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