scholarly journals Fabrication of Second Skin from Keratin and Melanin

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2568
Author(s):  
Chen Nowogrodski ◽  
Ido Simon ◽  
Shlomo Magdassi ◽  
Oded Shoseyov
Keyword(s):  
Mechanical Properties ◽  
High Resolution ◽  
Human Skin ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Light Transmittance ◽  
Fabrication Method ◽  
Melanin Content ◽  
Toxic Materials ◽  
High Resolution Images

Second skin is a topically applied, skin-conforming material that mimics human skin properties and bears potential cosmetic and e-skin applications. To successfully integrate with natural skin, characteristics such as color and skin features must be matched. In this work, we prepared bio-based skin-like films from cross-linked keratin/melanin films (KMFs), using a simple fabrication method and non-toxic materials. The films retained their stability in aqueous solutions, showed skin-like mechanical properties, and were homogenous and handleable, with non-granular surfaces and a notable cross-linked structure as determined by attenuated total reflection (ATR). In addition, the combination of keratin and melanin allowed for adjustable tones similar to those of natural human skin. Furthermore, KMFs showed light transmittance and UV-blocking (up to 99%) as a function of melanin content. Finally, keratin/melanin ink (KMI) was used to inkjet-print high-resolution images with natural skin pigmented features. The KMFs and KMI may offer advanced solutions as e-skin or cosmetics platforms.

scholarly journals Critical Factors for In Vivo Measurements of Human Skin by Terahertz Attenuated Total Reflection Spectroscopy

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4256
Author(s):  
Lixia Wang ◽  
Sayon Guilavogui ◽  
Henghui Yin ◽  
Yiping Wu ◽  
Xiaofei Zang ◽  
...  
Keyword(s):  
Human Skin ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Deep Penetration ◽  
Reference Spectrum ◽  
Critical Factors ◽  
Contact Duration ◽  
In Vivo Measurements ◽  
Different Types

Attenuated total reflection (ATR) geometry is a suitable choice for in vivo measurements of human skin due to the deep penetration of the field into the sample and since it makes it easy to measure the reference spectrum. On the other hand, there are several critical factors that may affect the terahertz (THz) response in these kinds of experiments. Here, we analyse in detail the influence of the following factors: the contact positions between the thumb and the prism, the contact pressure, the contact duration, and the materials of the prism. Furthermore, we use the THz-ATR technology to evaluate different types of handcream and also establish the theoretical model to investigate the reflectivity after interacting with the skin. The results agree well with experimental ones. Our analysis makes it clear the importance of controlling the above factors during measurements to enable reliable THz response and results which, in turn, may be used to monitor water motion in human skin and to predict possible diseases.

scholarly journals Comparison of Multilayer Transparent Wood and Single Layer Transparent Wood With the Same Thickness

2021 ◽  
Vol 8 ◽  
Author(s):  
Yan Wu ◽  
Yajing Wang ◽  
Feng Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Mechanical Strength ◽  
Light Transmission ◽  
Single Layer ◽  
Attenuated Total Reflection ◽  
Raw Material ◽  
Light Transmittance ◽  
Sodium Chlorite ◽  
Water Contact

In this paper, poplar was used as raw material, sodium chlorite was used to delignify it in acidic environment, and then epoxy resin was vacuum impregnated in the delignified wood template to prepare transparent wood. Moreover, in order to imitate the lamination method of plywood, the multilayer transparent wood was prepared by means of staggered vertical lamination. The purpose of this paper is to study the physical and chemical properties of multilayer transparent wood, and to explore the application potential of multilayer transparent wood as a new material by comparing with single layer transparent wood with the same thickness. The weight of wood components in the transparent wood prepared in this experiment accounts for about 30–45% of the weight of composite materials. Scanning electron microscopy (SEM) measurements, Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) characterization, weight gain measurements, UV transmittance measurements, color difference measurements, water contact angle measurements and mechanical properties measurements were used to study. The results showed that as the thickness of the transparent wood increased, the cracks between the resin and the wood cell wall increased, and the interface showed an uneven state. In the case of the same thickness, the multilayer transparent wood was made by laminating transparent wood sheets, with fewer internal cracks and smooth interfaces. Its light transmittance is better than single layer transparent wood. Moreover, compared with single layer transparent wood with the same thickness, the lightness of multilayer transparent wood decreased, and tended to yellow and red. Due to the removal of lignin, the tensile strength of transparent wood decreased during the preparation process. However, it can be seen from the mechanical strength test that the tensile strength of multilayer transparent wood is much higher than that of single layer transparent wood. To a certain extent, multilayer transparent wood can improve the mechanical strength of transparent wood. To conclude, multilayer transparent wood is a kind of natural transparent material with large thickness, good light transmission and excellent mechanical properties, and it has a good development prospect.

scholarly journals Photopatterning of PDMS Films: Challenging the Reaction between Benzophenone and Silicone Functional Groups

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2027
Author(s):  
Arthur Stricher ◽  
Renaud G. Rinaldi ◽  
Laurent Chazeau ◽  
François Ganachaud
Keyword(s):  
Mechanical Properties ◽  
Nuclear Magnetic Resonance ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Size Exclusion ◽  
Reaction Pathways ◽  
Aromatic Solvent ◽  
Exclusion Chromatography ◽  
Simplified Procedure

Direct photopatterning of PDMS (Polydimethylsiloxane) through benzophenone photo-inhibition has received great interest in recent years. Indeed, the simplicity and versatility of this technique allows for easy processing of micro-canals, or local control of PDMS mechanical properties. Surprisingly, however, the chemical reactions between silicone hydride and/or silicone vinyl groups and benzophenone have only been assessed through qualitative methods (e.g., Attenuated total reflection fourier transform infrared). In this communication, the previously proposed reaction pathways are challenged, using nuclear magnetic resonance (NMR) spectroscopy and size exclusion chromatography (SEC) monitoring. A different mechanism depicting the role of benzophenone irradiation on the polyaddition reaction of silicone formulations is proposed, and a simplified procedure involving aromatic solvent is finally disclosed.

Correction of Baseline Drifts due to the Pressure Changes between Attenuated Total Reflection Prism and Human Skin for Noninvasive Blood Glucose Sensing with Fourier Transform Infrared Spectroscopy

2011 ◽  
Vol 345 ◽  
pp. 119-123
Author(s):  
Dong Min Wang ◽  
Qi Peng Lu ◽  
Li Jun Yao
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Human Skin ◽  
Linear Regression Analysis ◽  
Fourier Transform Infrared ◽  
Glucose Sensing ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Pressure Changes

.For noninvasive blood sensing with attenuated total reflection (ATR)-Fourier Transform infrared spectroscopy(FTIR), the baseline of spectra human skin will drift because of the exitence of pressure changes between ATR prism and human skin . To correct the baseline drifts ,In the paper, the fingertips spectra in mid-infrared were recorded under the special conditions. A line equation was calculated using the last 14 spectra coupled with the linear regression analysis between the absorbance spectra at the 1035cm-1and the 950cm-1. And the corrected absorption intensities, after the removal of the baseline drifts, can be applied for the quantification of glucose concentrations in blood easily with the given method in the paper.

FeXIV Line Emission Polarization of the July 11, 1991 Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 541-547
Author(s):  
J. Sýkora ◽  
J. Rybák ◽  
P. Ambrož
Keyword(s):  
High Resolution ◽  
Solar Corona ◽  
Emission Line ◽  
Solar Eclipse ◽  
White Light ◽  
Preliminary Analysis ◽  
Line Emission ◽  
Total Solar Eclipse ◽  
Degree Of Polarization ◽  
High Resolution Images

AbstractHigh resolution images, obtained during July 11, 1991 total solar eclipse, allowed us to estimate the degree of solar corona polarization in the light of FeXIV 530.3 nm emission line and in the white light, as well. Very preliminary analysis reveals remarkable differences in the degree of polarization for both sets of data, particularly as for level of polarization and its distribution around the Sun’s limb.

Remarks on the application of backscattered electron imaging (BEI) to the scanning electron microscopy (SEM) of biological structures

1983 ◽  
Vol 41 ◽  
pp. 484-487
Author(s):  
Etienne de Harven
Keyword(s):  
High Resolution ◽  
Incident Beam ◽  
Spot Size ◽  
Primary Electron ◽  
Critical Point Drying ◽  
Cell Shapes ◽  
High Resolution Images ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
Scanning Electron

Biological ultrastructures have been extensively studied with the scanning electron microscope (SEM) for the past 12 years mainly because this instrument offers accurate and reproducible high resolution images of cell shapes, provided the cells are dried in ways which will spare them the damage which would be caused by air drying. This can be achieved by several techniques among which the critical point drying technique of T. Anderson has been, by far, the most reproducibly successful. Many biologists, however, have been interpreting SEM micrographs in terms of an exclusive secondary electron imaging (SEI) process in which the resolution is primarily limited by the spot size of the primary incident beam. in fact, this is not the case since it appears that high resolution, even on uncoated samples, is probably compromised by the emission of secondary electrons of much more complex origin.When an incident primary electron beam interacts with the surface of most biological samples, a large percentage of the electrons penetrate below the surface of the exposed cells.

Field Emission SEM Equipped With Noise Compensator

1973 ◽  
Vol 31 ◽  
pp. 302-303
Author(s):  
S. Saito ◽  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Contrast ◽  
Probe Current ◽  
High Resolution Images ◽  
Scanning Electron

Field emission scanning electron microscope (FESEM) features extremely high resolution images, and offers many valuable information. But, for a specimen which gives low contrast images, lateral stripes appear in images. These stripes are resulted from signal fluctuations caused by probe current noises. In order to obtain good images without stripes, the fluctuations should be less than 1%, especially for low contrast images. For this purpose, the authors realized a noise compensator, and applied this to the FESEM.Fig. 1 shows an outline of FESEM equipped with a noise compensator. Two apertures are provided gust under the field emission gun.

Low-Loss Images in a Stem/Tem Microscope

1976 ◽  
Vol 34 ◽  
pp. 496-497 ◽  
Author(s):  
David C. Joy ◽  
Dennis M. Maher
Keyword(s):  
High Resolution ◽  
Surface Topography ◽  
Beam Direction ◽  
Low Loss ◽  
Specimen Holder ◽  
Glancing Angle ◽  
High Resolution Images ◽  
Set Up ◽  
Conventional Manner ◽  
Objective Type

High-resolution images of the surface topography of solid specimens can be obtained using the low-loss technique of Wells. If the specimen is placed inside a lens of the condenser/objective type, then it has been shown that the lens itself can be used to collect and filter the low-loss electrons. Since the probeforming lenses in TEM instruments fitted with scanning attachments are of this type, low-loss imaging should be possible.High-resolution, low-loss images have been obtained in a JEOL JEM 100B fitted with a scanning attachment and a thermal, fieldemission gun. No modifications were made to the instrument, but a wedge-shaped, specimen holder was made to fit the side-entry, goniometer stage. Thus the specimen is oriented initially at a glancing angle of about 30° to the beam direction. The instrument is set up in the conventional manner for STEM operation with all the lenses, including the projector, excited.

Sign in / Sign up

Export Citation Format

Share Document