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Analysis of Biological Samples with Charged-Particle Accelerators
Published in Zeev B. Alfassi, Max Peisach, Elemental Analysis by Particle Accelerators, 2020
The sample is analyzed directly either as a thick target or a thin-layer target on a backing material. In a few cases, the samples are prepared as thin self-supporting targets only 3 to 5 mm in diameter.60,61 The majority of sample preparation methods have been developed for thin targets. Several of them involve the direct analysis of the biological or medical materials with a minimum of physical manipulation to prepare the target. In general, however, ideal targets would be flat and homogeneous both areally and in depth. When the final sample is to be mounted on a backing material, the backing material itself would be very thin to minimize the bremsstrahlung background and the heat loss in the target. In order to eliminate the background of characteristic X-rays, it should be entirely free from elements heavier than oxygen. It should be resistant to chemical attack, mechanical failure, heat damage, and radiation damage. Moreover, it should be inexpensive and readily available. Table 7 shows some materials which have been used as backing materials. Formvar is clear and very thin, but is the most fragile in the listed materials. Kapton is commercially available and has an excellent heat resistance. Polyvinylchloride contains some impurities and chlorine is a serious interfering element. Mylar is easily available, has very little impurities, is quite resistant to heat, and has a good physical and chemical strength. As it is very hydrophobic, an aqueous sample pipetted on the surface can be dried into a small point. When the backing film is used, its impurities must be checked continuously by preanalyzing as blank tests.
Effect of a new modified polyamidoamine dendrimer biomimetic system on the mineralization of type I collagen fibrils: an in vitro study
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Fangfang Xie, Jindong Long, Jing Yang, Hejia Qin, Xuandong Lin, Wenxia Chen
Lyophilized type I collagen powder derived from calf skin (Advanced BioMatrix, San Diego, CA, USA) was dissolved in 0.02 M hydrochloric acid, containing 2 μL/mL phenol red, overnight at 4 °C to obtain a collagen solution. Then, 64 μL of the solution was placed on an inert polyethylene substrate in a Petri dish and a 400-mesh carbon-coated and formvar-coated Ni transmission electron microscope grid (Zhongxing-Bairui, Beijing, China) was placed on top of each droplet. A dish containing 25% ammonium hydroxide solution (v/v) was placed in the Petri dish. Then, the Petri dish was incubated at 37 °C inside the humidity chamber until the collagen solution was neutralized with ammonia vapor. Once neutralization of the collagen solution by ammonia vapor was evident from the color change of the pH indicator, the ammonium hydroxide solution was removed. The collagen solution was left to gel by further incubation at 37 °C for 24–48 h. Cross-linking of the reconstituted collagen fibrils was performed by allowing the collagen-coated grids to float upside down in 0.3 M 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/0.06 M N-hydroxysuccinimide (Shanghai yuanye Bio-Technology, Shanghai, China) for 4 h [11,17]. The collagen-coated grids were used for subsequent experiments, after confirmation of recombinant collagen fibrils using transmission electron microscopy (TEM).
Pretreatment of bio-oil with ion exchange resin to improve fuel quality and reduce char during hydrodeoxygenation upgrading with Pt/C
Published in Environmental Technology, 2021
Shinyoung Oh, In-Gyu Choi, Joon Weon Choi
The morphology of the solid acid catalyst (amberlyst 36, used in the pretreatment) was investigated by FE-SEM (field-emission scanning electron microscopy, SIGMA). The metal catalysts (Pt/C, used in second-stage hydrodeoxygenation) were mounted on a carbon- and formvar-coated grid and observed using EF-TEM (energy-filtering transmission electron microscope, LIBRA 120) at an accelerating voltage of 120 kV.
A Facile Route to Synthesize Gold Prisms Up to Micrometer Scale Based on Slow Reduction Methods
Published in Journal of Dispersion Science and Technology, 2011
Aizhen Liu, Yingwen Cheng, Fang Tian, Wei Pan, Shaoxin Huang, Xingli Feng, Houyi Ma
The samples for scanning electron microscope (SEM) measurements were prepared either by directly dipping the Formvar-coated copper grids into the solutions to deposit the gold particles on them, followed by naturally evaporating the solvent, or by spontaneous deposition of gold nanostructures on the glass slides.