Oils Colored with Wood-Staining Fungal Pigments : Color Loss, Oxidation, and Structural Breakdown

Wood-staining fungal pigments have potential uses as colorants for wood and textiles. Traditionally, organic solvents have been used as carriers for these pigments. However, other environmentally-friendly and more readily available carriers must be found. Natural oils have the potential to carry these pigments but have demonstrated color loss over relatively short periods of time, possibly due to oxidation and/or polymerization of both the oils and pigments. The current study examined therapeutic and food grade oils (instead of finishing oils) for their potential to carry draconin red, the pigment from Scytalidium cuboideum. To track color loss over time for treated and untreated pigmented oils, a colorimeter and the CIE2000 L*a*b* color space were used. It was determined that hemp oil was a potential carrier for draconin red, as were flax seed oil and cold-pressed linseed oil when treated with β-carotene as the pigment did not degrade over time in these oils. FTIR analysis was used to determine if oxidation was occurring in the oils and if changes in draconin red could be tracked. Based on the FTIR analysis, oxidation was not likely the cause of color loss in the pigmented oils and the pigment could not be distinguished from the oils in the IR spectra. Finally, SEM was employed to determine if crystal degradation was contributing to color loss. The SEM analysis indicated, surprisingly, that the crystals of draconin red formed rather than degraded over time, so crystal breakdown was also not likely the cause of color loss. Further in-depth chemical studies are needed to determine the mechanism of color loss in pigmented natural oils

A comparative analysis of extracted fungal pigments and commercially available dyes for colorizing textiles

With the resurgence in the interest of using natural textile dyes, a solution must be found that will overcome the limitations of traditional natural dyes. This solution must also be safer for both humankind and the environment than are synthetic dyes. This study compares the colorfastness of commercially available synthetic and natural dyes to wood-staining fungal pigments on both unmordanted and mordanted fabrics. Colorfastness to rinsing, washing, perspiration, and crocking were tested using AATCC standard test methods. A modification of the AATCC standard test method for colorfastness to light was developed using a QUV Accelerated Weathering Tester. Colorfastness was determined using statistical analyses of overall color changes as determined by color readings taken with a colorimeter and using the CIE L*a*b* color space. Results indicate that the wood-staining fungal pigments, especially xylindein, show good potential as a competitor to both synthetic and natural dyes. There are, however, some limitations, such as color intensity and consistency of performance, which still need to be researched and overcome

Mechanical Color Reading of Wood-Staining Fungal Pigment Textile Dyes: An Alternative Method for Determining Colorfastness

Colorfastness to washing and crocking (color loss due to rubbing) are essential qualities for any dye/fabric combination that will be used for garments or upholstery. In this study, colorfastness to washing and crocking of fabrics dyed with wood-staining fungal pigments was compared to colorfastness of commercial dyes using an alternative mechanical testing method. Overall, wood-staining fungal pigments out performed commercial dyes for colorfastness to washing and wet and dry crocking. Xylindein was the most colorfast dye. Draconin red yielded inconsistent results, and the yellow pigment required a mordant to achieve any colorfastness. This study showed that the mechanical color reading method, along with statistical analysis, provided an objective, repeatable gauge of colorfastness, although visual inspection is also needed for practical purposes

Comparing Colorfastness to Light of Wood-Staining Fungal Pigments and Commercial Dyes: An Alternative Light Test Method for Color Fastness

Colorfastness to light is an essential quality for textiles exposed to sunlight for a significant length of time. In this study, the colorfastness (specifically to light) of fabrics dyed with wood-staining (spalting) fungal pigments was compared to the colorfastness of commercial dyes. A short-duration immersion dying method without heat was used to minimize both water and energy usage. Both mordanted and unmordanted fabrics were tested and compared for colorfastness. Additionally, a new method of testing for colorfastness to light was developed. Results indicate that the wood-staining fungal pigments demonstrate superior colorfastness to light over commercial dyes when the employed dyeing method is used. Additionally, the colorfastness to light testing method developed using the L-2 Blue Wool Standard and QUV Accelerated Weathering Machine is a viable alternative to current standard colorfastness to light testing methods

Stability of the Fungal Pigment from Scytalidium cuboideum Carried in Food-Grade Natural Oils

Wood-staining fungal pigments have shown potential use as colorants for wood and textiles, with organic solvents as the pigment carrier. Natural oils have been suggested as an environmentally friendly and more available carrier; however, oils promoted color degradation. The current study examined the mechanism of said degradation and tested therapeutic and food-grade oils (instead of finishing oils) for their potential to carry draconin red, the pigment from Scytalidium cuboideum, without color loss over time. FTIR analysis from finishing oils indicated that oxidation was not likely the cause of color loss as the pigment could not be distinguished from the oils in the IR spectra. SEM was employed to determine if crystal degradation was contributing to color loss and indicated, surprisingly, that the crystals of draconin red formed rather than degraded over time. This suggested crystal breakdown was also not likely the cause of color loss. The pigment did not show degradation in hemp oil, flaxseed oil, and cold-pressed linseed oil when treated with β-carotene. Further in-depth chemical studies are needed to determine the mechanism of color loss in pigmented natural oils; however, food-grade oils appear to be a promising alternative to carry draconin red, without degradation of the color

Timing of Intubation in Coronavirus Disease 2019: A Study of Ventilator Mechanics, Imaging, Findings, and Outcomes

Objectives:. Determine the variation in outcomes and respiratory mechanics between the subjects who are intubated earlier versus later in their coronavirus disease 2019 course. Design:. Retrospective cohort study. Setting:. Northwestern Memorial Hospital ICUs. Patients:. All patients intubated for coronavirus disease 2019 between March 2020 and June 2020. Interventions:. Patients were stratified by time to intubation: 30 subjects were intubated 4–24 hours after presentation and 24 subjects were intubated 5–10 days after presentation. Baseline characteristics, hospitalization, ventilator mechanics, and outcomes were extracted and analyzed. Ten clinically available CT scans were manually reviewed to identify evidence of pulmonary vascular thrombosis and intussusceptive angiogenesis. Measurements and Main Results:. Median time from symptom onset to intubation was significantly different between the early and late intubation cohorts, with the latter being intubated later in the course of their illness (7.9 vs 11.8 d; p = 0.04). The early intubation cohort had a lower mortality rate than the late intubation cohort (6% vs 30%, p < 0.001) without significantly different respiratory mechanics at the time of intubation. The late intubation cohort was noted to have higher dead space ratio (0.40 vs 0.52; p = 0.03). On review of CT scans, the late intubation cohort also had more dilated peripheral segments on imaging (two segments vs five segments). Conclusions:. The question as to whether delaying intubation is beneficial or harmful for patients with coronavirus disease 2019-induced hypoxemic respiratory failure has yet to be answered. As our approaches to coronavirus disease 2019 continue to evolve, the decision of timing of intubation remains paramount. Although noninvasive ventilation may allow for delaying intubation, it is possible that there are downstream effects of delayed intubation that should be considered, including the potential for pulmonary vascular thrombosis and intussusceptive angiogenesis with delayed intubation