Podcasts about colorimetric

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.14.095778v1?rss=1 Authors: Amano, K., Xiao, K., Wuerger, S., Meyer, G. Abstract: The main ingredient of sunless tanning products is dihydroxyacetone (DHA). DHA reacts with the protein and amino acid composition in the surface layers of the skin, producing melanoidins, which changes the skin colour, imitating natural skin tan caused by melanin. The purpose of this study was to characterise DHA-induced skin colour changes and to test whether we can predict the outcome of DHA application on skin tone changes. To assess the DHA-induced skin colour shift quantitatively, colorimetric and spectral measurements of the inner forearm were obtained before, four hours and 24 hours after application of a 7.5% concentration DHA gel in the experimental group ( n =100). In a control group ( n =60), the same measurements were obtained on both the inner forearm (infrequently sun-exposed) and the outer forearm (frequently sun-exposed); the difference between these two areas was defined as the naturally occurring tan. Skin colour shifts caused by DHA tanning and by natural tanning were compared in terms of lightness ( L *), redness ( a *) and yellowness ( b *) in the standard CIELAB colour space. Naturalness of the DHA-induced skin tan was evaluated by comparing the trajectory of the skin chromaticity distribution in ( L *, b *) space with that of naturally occurring skin tan. Twenty-four hours after DHA application, approximately 20% of the skin colour samples became excessively yellow, with chromaticities outside the natural range in ( L *, b *) space. A principal component analysis was used to characterise the tanning pathway. Skin colour induced by DHA was predicted by using a multiple regression on the chromaticities and skin properties of the original skin colour with a median error of less than 2 {Delta}E. We conclude that the control of both, the magnitude as well the direction of the colour shift is a critical factor to achieve a natural appearance. Copy rights belong to original authors. Visit the link for more info

Ron Ellis, Chair of Idealliance Print Properties & Colorimetric Council and leading global brand consultant joins Idealliance CEO Tim Baechle to talk passionately about Idealliance’s focus on global collaboration and service to others as the critical cornerstones of our work around the world. Continuing with the work that has come out of PPC that is utilized across the globe, the work that is currently being done within PPC, the tremendously brilliant global contributors who give their time in service to further this incredible industry, and an invitation to the world to join, it is in service and collaboration that Idealliance exists and is Powering the Supply Chain®. Guests: Tim Baechle, CEO, Idealliance & Ron Ellis, Chair, Idealliance PPC. GAMUT is produced and published by Idealliance - become a member today and join us in creating the future of our industry. Learn more about Idealliance Certification Programs such as: G7®, BrandQ®, Color Management Professional® and Print Planning & Estimating Professional®. This episode of GAMUT is brought you by Konica-Minolta. Support the show (https://www.idealliance.org/idealliance-membership)

Esko’s Mark Samworth demystifies seven-color process printing for flexography, offset, and digital. A leading patent holder in a variety of technologies including expanded gamut printing, Mark provides insight into the value, history, and future of this technology through his experience and current work in developing standards and specifications through Idealliance’s Print Properties & Colorimetric Council Extended Color Gamut Global Technical Subcommittee. Guest: Mark Samworth, Color Specialist at Esko. GAMUT is produced and published by Idealliance - become a member today and join us in creating the future of our industry. Learn more about Idealliance Certification Programs such as: G7®, BrandQ®, Color Management Professional® and Print Planning & Estimating Professional®. This episode of GAMUT is brought you by Konica-Minolta. Support the show (https://www.idealliance.org/idealliance-membership)

Introduction: Human mesenchymal stem cells (hMSC) are easily obtainable from bone mar-row and possess the ability to differentiate into osteoblasts. Therefore, they have been sug-gested as a suitable source for bone regeneration. HMSC are equipped with a variety of in-tegrins that mediate essential cell-matrix interactions. Collagen I represent approximately 90% of the bone protein content. Cell attachment to collagen I is mediated by three members of the integrin receptor family named a1b1, a2b1 and a11b1 integrins. The main aim of this doctoral thesis was to investigate the basal expression of those integrins in hMSC and to func-tionally analyze the knockdown effect of a single collagen I-binding integrin on hMSC behav-ior in vitro. Materials and methods: HMSC were cultured on collagen I-coated surface. A lentiviral trans-fer of a1-, a2- and a11-specific shRNA was applied for downregulation of the corresponding integrin mRNA. Quantitative PCR and western blot analysis were used to assess the basal ex-pression, knockdown efficiency and integrin compensation. Colorimetric adhesion assay was used for estimation of the extent of cells attachment. HMSC spreading and migration was ob-served by time lapse experiments. JC-1 staining was used for investigation of the initiation of apoptosis. Results: Quantitative PCR were used to assess the basal expression of collagen I-binding integrins in three hMSC donors. We found that these integrins are differently expressed as integrin a11 had the highest and integrin a2 the lowest expression. Next, we applied lentiviral delivery of target-specific short hairpin RNA (shRNA) in order to knockdown each of the collagen I-binding integrins and compared them to the hMSC transduced with a sequence against a non-human gene abbreviated as shRNA control. We achieved significant downregulation (> 80%) of the collagen I-binding integrin mRNA and protein. Subsequently to the transduction, we did not noticed pronounce morphological cell changes, however, a clear decrease of a2- and a11-knockdown hMSC numbers was observed during cultivation. Using a quantitative adhesion assay, we estimated that 120 min after plating only 30% of integrin a11-deficent cells were able to attach to collagen I. In contrast, at the same time point, 70% of integrin a2-knockdown hMSC were attached while integrin a1- and shRNA control hMSC have already reached 100% cell adhesion. Furthermore, a time lapse-based investigation showed that integrin a1- and shRNA control hMSC need approximately 35 min to fully spread on collagen I. In contrast, integrin a2- and a11-knockdown hMSC took approximately double more time for spreading in comparison to shRNA control hMSC. Additionally, we analyzed the migration capability of the four different hMSC lines. The average path which integrin a1- and shRNA control hMSC passed was approximately 170 µm with mean speed of 11.5 µm/h. In parallel integrin a2 and a11-deficient hMSC migrated to a distance of approximately 70 µm with a velocity of 5 µm/h. Since it was observed a lost of a2- and a11-deficient hMSC, next we performed JC-1 staining that visualizes mitochondrial leakage, a hallmark of apoptosis. The majority of integrin a2- and a11-knockdown hMSC exhibited mitochondrial leakage whereas integrin a1- and shRNA control hMSC showed intact mitochondria. Finally, we used quantitative PCR to investigate whether there were compensatory effects between the three integrin receptors. We detect that knockdown of integrin a1 led to upregulation of a2 and a11. Similarly, when integrin a2 was downregulated, integrin a1 and a11 expression increased. Interestingly, knockdown of integrin a11 caused only a slight increase in integrin a1 but not in a2 expression. We also observed that upon osteogenic stimulation, integrin a2 and a11-deficient hMSC further reduced in number and did not mineralize the matrix even on a single cell level. Moreover, our preliminary investigation in hMSC-derived from osteoporosis suffering patients showed a tremendous downregulation of integrin a2. Conclusions: Our results strongly suggested that integrins a2b1 and a11b1 mediate an indis-pensible signaling for hMSC. Once these receptors were ablated from cell surface, hMSC re-duced their spreading, adhesion, migration and survival rates. Our integrin knockdown mod-els can be used for further investigations and understanding of the integrins a2b1 and a11b1 importance and signaling in hMSC and hOB since we observed a strong downregulation of integrin a2 expression in osteoporosis.

The reporter gene for beta -galactosidase is frequently used to determine the efficiency of gene transfer in arteries. However, blood is often present in arterial explants and may compromise the results by the presence of hemoglobin. The light absorption of hemoglobin is similar to the absorption of several colorimetric products of the commonly used beta -galactosidase substrates, including o-nitrophenyl-beta -D-galactopyranoside (ONPG) and chlorophenol red galactopyranoside (CPRG), This may result in false-positive measurements of beta -galactosidase enzyme activity. The aim of this investigation was to determine the most appropriate method for quantification of beta -galactosidase activity in the presence of blood. Colorimetric substrates (ONPG, CPRG) or the chemiluminescent Galacton-Plus substrate were used, and light absorption was measured at different concentrations of erythrocyte extract. Among the beta -galactosidase substrates tested, CPRG was the most appropriate, allowing detection of enzyme activity at concentrations as low as 0.05 mU, independent of blood contamination. Addition of reducer stabilized enzyme activity for at least 5 h. Endogenous beta -galactosidase activity was evaluated and used to correct results. CPRG substrate, in combination with the reducer agent mercaptoethanol, was found to be the optimal reagent for quantifying beta -galactosidase activity in the presence of blood after nonviral in vivo reporter gene transfection, even with a relatively low transfer efficiency. Copyright (C) 2000 S. Karger AG, Basel.