China
Africa
Explore chapters and articles related to this topic
Industrial Applications
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
When ions of sufficient electronic energy loss traverse a dielectric film or foil, they alter the chemical bonding along their nominally straight path within the material. A suitable etchant can quickly dissolve these so-;called latent tracks leaving holes of small diameter (~10 nm) but long length – several µm. By continuing the etching process gradually, increase of the diameter reproducibly and uniformly is achieved (Felter et al. 2005). The trackable medium can be applied as a uniform film onto large substrates. The small, monodisperse holes produced by this track etching can be used in conjunction with additional thin-film processing to create functional structures attached to the substrate. For example, Lawrence Livermore National Laboratory and Candescent Technologies Corporation (CTC) co-developed a process to make arrays of gated field emitters (~100 nm diameter electron guns) for CTC's Thin CRT™ displays, which have been fabricated to diagonal dimensions >13 in. (Felter et al. 2005).
Skin Perforation and Solid Microneedles
Published in Boris Stoeber, Raja K Sivamani, Howard I. Maibach, Microneedling in Clinical Practice, 2020
Michael L Crichton, Mark Kendall
Manufacturing from silicon makes use of either dry or wet etching of crystalline silicon wafers. This starts by defining a mask that is deposited on the surface, often using photolithography, which defines the areas for either anisotropic or isotropic etching. Wet etching is considered a simpler manufacturing process, as isotropic etching erodes material with orientation to the crystal structure of the material. This will give microneedle shapes that are generally blunter than dry etching (20). Dry etching, similar to that used in the microelectronic industry, can perform both anisotropic etching (etching vertically downward to make high aspect ratios) and isotropic etching (removal in all directions simultaneously). This approach can give some high-aspect-ratio structures with very sharp tips (sub-micron) (21, 22).
Freeze Fracture in Lung Research
Published in Joan Gil, Models of Lung Disease, 2020
Freeze etching is a specialized ultrastructural technique in which frozen samples are fractured under vacuum with or without subsequent partial sublimation of the surrounding ice (etching). The exposed surface is then replicated with a heavy metal, usually platinum. To strengthen the replica, a layer of carbon is further evaporated onto the surface. The underlying sample is removed by soaking in sodium hypochlorite or a strong acid and the resulting surface replica is mounted on a copper grid and viewed in the electron microscope. The steps involved in freeze etching are briefly outlined below. For greater detail, the reader is referred to the monograph edited by Rash and Hudson (1979).
Streptococcus mutans levels in patients who received orthodontic brackets bonded using probiotic impregnated resin composite – a randomized clinical trial
Published in Biomaterial Investigations in Dentistry, 2023
Krishnaraj Rajaram, Poornima R. Jnaneshwar, Azmina Idaayath, Ravi Kannan
Prior to bonding of the brackets, moisture control was achieved by a saliva ejector and cheek retractor, and to improve isolation, cotton rolls were placed in the sulcus. Etching was performed with 37% orthophosphoric acid (Eazetch, Anabond Steadman Pharma Research (P) Ltd) applied for 20 s. Teeth were then rinsed for 15 s and dried with compressed air. After application of primer (Orthofix, Anabond Steadman Pharma Research (P) Ltd), probiotic impregnated composite was used to bond each bracket in the experimental group and light-cured conventional resin composite (Orthofix, Anabond Steadman Pharma Research (P) Ltd) was used in the control group. Photopolymerisation was performed using an LED curing unit(Ivoclar Bluephase N MC). The polymerization time was 40 s, 20 s for each of the mesial and distal aspect.
Dentine biomodification by sulphonamides pre-treatment: bond strength, proteolytic inhibition, and antimicrobial activity
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Maristela Barbosa Portela, Caroliny Mello Barboza, Eduardo Moreira da Silva, Daniel Clemente de Moraes, Renata Antoun Simão, Clara Ribeiro de Souza, Verônica da Silva Cardoso, Antônio Ferreira-Pereira, Alane Beatriz Vermelho, Claudiu T. Supuran
Since adhesion requires intimate contact between the adhesive material and the substrate, the dentine surface’s wetting process directly influences the adhesive interface’s quality. The degree of propagation of a liquid over a surface is the measure of wettability, which can be quantified by determining the contact angle15. For the use of conventional adhesive systems, whether simplified or not, acid etching dissolves the smear layer, which is removed by subsequent washing, allowing direct contact of the adhesive with demineralised dentine and, as a result, better surface wettability15. Given the above, a treatment after acid etching would negatively affect the contact angle. Therefore, considering the different dentine treatments evaluated, the SULFA1 and SULFA2 groups led to contact angles statistically equal to the CTR group, suggesting that the treatment with these inhibitors could not change the penetration of the adhesive and the formation of the hybrid layer. Thus, the first hypothesis was entirely accepted since sulphonamide derivatives did not influence dentine wettability. These results may be associated with the presence of -NH endings in the SULFA1 and SULFA2 groups, which allow the interaction with the water molecules present in the demineralised dentine through hydrogen bonds49, in addition to interacting with the hydrophilic endings of the adhesive monomers, allowing a better wettability on the substrate pre-treated with the derivatives.
The most promising microneedle device: present and future of hyaluronic acid microneedle patch
Published in Drug Delivery, 2022
Huizhi Kang, Zhuo Zuo, Ru Lin, Muzi Yao, Yang Han, Jing Han
It is worth mentioning that the preparation of HA MNP is very time-consuming. This is the main reason to limit the large-scale use of HA MNP. Preparation methods such as micro-molding, laser cutting, photolithography (Lee et al., 2010), and wet and dry etching (Roh et al., 2022) have now been developed. But industrial production requires a more simple method. Recently, 3 D printing has been introduced as a powerful MNP fabrication strategy. Ouyang et al. (Ouyang et al., 2020) investigated bio-inks represented by MeHA, which can meet the physicochemical requirements of printing and provide an ideal environment for encapsulating cells. Petta D et al. summarized the recent research progress of HA-containing bio-inks for 3 D printing (Petta et al., 2020), giving us a lot of inspiration for choosing the right bio-ink to prepare HA MNP. We hope that in the future, we can find the perfect bio-inks for HA MNP printing.