Search results for "Integument"
showing 10 items of 754 documents
Characterization and osteogenic activity of a silicatein/biosilica-coated chitosan-graft-polycaprolactone.
2014
Several attempts have been made in the past to fabricate hybrid materials that display the complementary properties of the polyester polycaprolactone (PCL) and the polysaccharide chitosan (CHS) for application in the field of bone regeneration and tissue engineering. However, such composites generally have no osteogenic activity per se. Here we report the synthesis of a chitosan-graft-polycaprolactone (CHS-g-PCL) and its subsequent characterization, including crystallinity, chemical structure and thermal stability. Upon surface-functionalization of CHS-g-PCL with osteogenic biosilica via the surface-immobilized enzyme silicatein, protein adsorption, surface morphology and wettability were a…
Snapshot RGB mapping of skin melanin and hemoglobin.
2015
The concept of snapshot red-green-blue (RGB) multispectral imaging was applied for skin chromophore mapping. Three monochromatic spectral images have been extracted from a single RGB image dataset at simultaneous illumination of skin by 473-, 532-, and 659-nm laser lines. The spectral images were further transformed into distribution maps of skin melanin, oxyhemoglobin, and deoxyhemoglobin, related to pigmented and vascular skin malformations. The performance and clinical potential of the proposed technique are discussed
Unmixing of human skin optical reflectance maps by Non-negative Matrix Factorization algorithm
2013
International audience; We present in this paper the decomposition of human skin absorption spectra with a Non-negative Matrix Factorization method. In doing so, we are able to quantify the relative proportion of the main chromophores present in the epidermis and the dermis. We present experimental results showing that we obtain a good estimate of melanin and hemoglobin concentrations. Our approach has been validated by analyzing the human skin absorption spectra in areas of healthy skin and areas affected by melasma on eight patients.
ZnS Ultrathin interfacial layers for optimizing carrier management in Sb2S3-based photovoltaics
2021
Antimony chalcogenides represent a family of materials of low toxicity and relative abundance, with a high potential for future sustainable solar energy conversion technology. However, solar cells based on antimony chalcogenides present open-circuit voltage losses that limit their efficiencies. These losses are attributed to several recombination mechanisms, with interfacial recombination being considered as one of the dominant processes. In this work, we exploit atomic layer deposition (ALD) to grow a series of ultrathin ZnS interfacial layers at the TiO2/Sb2S3 interface to mitigate interfacial recombination and to increase the carrier lifetime. ALD allows for very accurate control over th…
Impurity analyses of silicon wafers from different manufacturing routes and their impact on LID of finished solar cells
2013
Summarizes the measurements of impurity concentrations in directionally solidified silicon ingots from different feedstocks. The substitutional Carbon and interstitial Oxygen are measured on as-sawn wafers using FTIR. Active iron concentration is mapped on a-Si:H passivated wafers. It is observed that these impurities present in Elkem Solar Grade Silicon (ESS™) concentrations are comparable to the standard polysilicon which are in the acceptable ranges for silicon for solar industry. The measured LID of the finished solar cells is also comparable.
Irradiance Dependent Temperature Coefficients for MC Solar Cells from Elkem Solar Grade Silicon in Comparison with Reference Polysilicon
2014
Abstract An increase in sun intensity enhances the output power of the solar cells, but at the same time the rise of cell temperature affects its electrical performance negatively. The present authors have made a comparative study on temperature coefficients at various irradiances of multicrystalline solar cells made from the standard Siemens process and from material produced by a metallurgical route – the Elkem Solar Silicon (ESS®) process. Such temperature coefficients measured while exposed to various irradiance levels are essential to build a better understanding and prediction of field performance of solar cells manufactured from various feedstock types. In the current experiment, the…
UV-induced Degradation Study of Multicrystalline Silicon Solar Cells Made from Different Silicon Materials
2013
Abstract The effect of ultraviolet-induced degradation (UV-ID) on solar cells made from two different solar grade materials has been compared. By using identical wafer and cell production units, effects originating in the two materials; solar grade produced by the Elkem Solar method (ESS™) was compared to standard polysilicon solar cells. Silicon wafers were selected precisely from similar positions from respective silicon bricks to process identical standard solar cells. The quantum efficiency maps at particular laser wavelengths and IV parameters of all solar cells were measured before and after UV-ID to visualize defects sites in the solar cells and to observe the extent of degradation. …
Role of TiO2 in Highly Efficient Solar Cells
2021
Titanium dioxide (TiO2) is a naturally occurring oxide of titanium. It has a wide range of applications. It has three metastable phases, which can be synthesized easily by chemical routes. Usage of TiO2 in thin-film solar cells has gained much attention in increasing the performance of the cell. The objectives are to harvest the freely available earth’s energy and to gain expertise in yielding a maximum conversion efficiency. Various strategies are employed to face the challenges in improving the efficiency of solar cells. This study provides a broad view of the usage of different forms of TiO2 layers, like nanochannel, porous, nanotubes, and mesoporous layers, in enhancing electron injecti…
Modelling of Reflectance Spectra of Skin Phototypes III
2011
In dermatology, study of human skin colour is related to skin phototype (SPT) in which the Fitzpatrick's scale is the most used skin photo type classification. Assessment of skin response to UV for various reasons plays an important role in dermatology. This is however not easy to be performed because of two reasons. Firstly, skin areas may have different skin tone resulting in different reflectance spectra and secondly, different modalities may produce different reflectance spectra. We hypothesize that the underlying pattern of reflectance spectra must be similar regardless of the modalities use and the skin areas where it is obtained, for a particular person. An observational clinical stu…
Effect of diamond microdermabrasion on oily skin: a case report
2018
Background: The history of microdermabrasion dates back to ancient Egypt. The first treatment in Europe occurred in 1985 and has since become a popular method of exfoliation of the superficial layers of skin. Microdermabrasion is an effective method of taking care of the skin of the face and body, bringing about immediate effects in the treatment of deep scars and stretch marks. Aim of the study: To determine the effectiveness of diamond microdermabrasion on a person with hyperuricemia of the sebaceous glands. Materials and methods: Based on interviews, a case analysis, and the impact of diamond microdermabrasion on the structure of the skin’s surface, the level of hydration, oiliness and e…