Liquid paraffin

About: Liquid paraffin is a research topic. Over the lifetime, 6185 publications have been published within this topic receiving 52956 citations.

An evaluation of dermoscopy fluids and application techniques.

Abstract: SummaryBackground Dermoscopy, a noninvasive technique used to help physicians better visualize pigmented skin lesions, is becoming widely used by dermatologists. Yet despite its popularity, to our knowledge basic aspects such as the best immersion fluid (IF) to use and proper procedures for applying the IF and dermatoscope have never been the subject of a systematic investigation. Objectives To determine the best techniques for application of IF and the dermatoscope; to discover which IF results in the least amount of air inclusions; to determine which IF provides the best image quality. Methods and materials This study was divided into three phases. Phase I examined several techniques of taking digital dermoscopic photographs in an attempt to eliminate air bubbles. Phase II tested seven IFs to analyse quantitatively the number of air inclusions for each IF. Phase III investigated these same IFs to judge the image quality for each. Results Phase I: in our hands, the best technique to apply an IF is to use an eyedropper and place the IF directly onto the skin in combination with a ‘roll-on technique’: the dermatoscope's edge is placed on the skin first and is then rotated until the glass plate lies flat against the skin. Phase II: the alcoholic IF resulted in the least amount of air bubble inclusions (70% ethanol, 90% isopropanol and alcoholic disinfectant), while liquid paraffin (a mineral oil) resulted in the most air bubbles. Phase III: dermoscopic structures were equally clear with alcohols and liquid paraffin, but slightly blurry with ultrasound gel and water. Conclusions Although 90% isopropanol performed slightly better in terms of air inclusions, we prefer to use 70% ethanol in most circumstances because it has the advantage of being odourless, unlike its counterpart. Additionally, ethanol will not stain clothing, does not crystallize on the dermatoscope, disinfects and evaporates immediately (does not need to be wiped off). For certain local considerations, such as dermoscopy on mucosa or the nail, we prefer to use ultrasound gel because it will not flow.

Properties and Sensing Performance of All-Dielectric Metasurface THz Absorbers

Abstract: We have designed, fabricated, and experimentally verified highly sensitive all-dielectric metasurface THz absorbers (AMTAs) device in the terahertz (THz) frequency range. By designing different structures of the resonant, different types of absorber, which have perfect absorption can be realized. The proposed AMTA with simplified designs is demonstrated by single-layer all-silicon array. Furthermore, the simulated results of absorption frequency changes under different refractive index demonstrate that the proposed AMTAs can act as refractive index sensors in the biochemical application, such as detection of liquid paraffin, cancer cells, and ethanol. Also, experiments of detecting different concentrations of 2, 4-Dichlorophenoxyacetic acid (2, 4-D) have demonstrated that the proposed absorbers have great potential to improve the performance in biological and chemical sensing. These results show that the AMTAs can be used as sensors, which can detect the presence of trace pesticides and residues of some chemicals in adsorption analyses, among other practical applications.

Synthesis of two-dimensional single-crystal berzelianite nanosheets and nanoplates with near-infrared optical absorption

Abstract: The solar cell industry requires convenient and inexpensive fabrication of semiconductor nanostructures as highly efficient absorptive layers with low-cost, environmentally benign, heavy-metal-free (i.e., free from Hg, Cd, and Pb) and suitable band gap near 1 eV features. In this paper, we demonstrate the synthesis of two-dimensional single-crystal berzelianite (Cu2−xSe) nanosheets (in-plane diameter-to-thickness ratio ∼100) and nanoplates (in-plane diameter-to-thickness ratio ∼10) via a simple, “green” and environmentally benign method of injecting Cu(I)-complex precursor into Se-solution in paraffin liquid. Unlike the previous syntheses of binary chalcogenide nanostructures such as CdSe, the current strategy for berzelianite synthesis does not use expensive and toxic phosphine ligands such as trioctylphosphine (TOP). The products were characterized by a range of methods, such as X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and selected area electron diffraction, revealing that the products have the cubic phase and high-quality single-crystal two-dimensional nanostructure. UV-Vis-NIR absorption spectroscopy reveals that the nanosheets and nanoplates show obvious absorption onsets at 0.89 eV and 0.80 eV, respectively, and strong optical absorption peak at 1.70 eV and 1.62 eV, covering the whole red range of the solar spectrum. The present study opens a new avenue to “green” and low-cost controllable synthesis of binary chalcogenides with technological applications in solar energy conversion and also in a wide range of photonic devices operating in the near-infrared.