Terri Von Hoven

Biased Experimental Fineness and Maturity Results

In an earlier paper, we developed models and performed computer simulations to understand the variability in coefficients of determination (R2) between fineness and maturity, micronaire and fineness, and micronaire and maturity of cotton. We subsequently concentrated on derivation and testing of several diagnostic models to enhance the R2 and provide information about the analytical quality (accuracy) of the results. We then introduced modeling of biased fineness and maturity results. Error functions were derived based on micronaire values, specifically, Lords micronaire model. This paper demonstrates testing of a key diagnostic model on two different sample sets of 21 cottons. The results from one sample set — analyzed on the fineness and maturity tester — fit the model. Results from the other sample set — analyzed on both the advanced fiber information system (AFIS) A-2 and AFISPRO — demonstrate a lack of fit to the diagnostic model. This lack of fit is due to bias in the AFIS fineness and maturity measurements compared to the more traditional Lords micronaire model. As a consequence of the bias, the dynamic range of the AFIS raw data for both fineness and maturity is very narrow. Results are confirmed by image analysis.

Preliminary evidence of oxidation in standard oven drying of cotton: attenuated total reflectance/Fourier transform infrared spectroscopy, colorimetry, and particulate matter formation:

Currently, oven drying in air is often utilized to generate the percentage of moisture in cotton fibers. Karl Fischer Titration, another method for cotton moisture measurement, has been compared to the oven drying method. The percentage of moisture as generated by the oven method tracks those of Karl Fischer Titration, but there are differences between the two. In fact, a bias exists in the measured moisture loss employing the standard oven drying method. In addition, the moisture data collected via Karl Fischer Titration demonstrates smaller variances than those data collected in the oven. The aim of this study is to determine what is causing those differences. In the current report, particulate matter formation and browning of oven-treated cotton samples have been observed, suggesting visible indirect evidence that cotton oxidation may be occurring. It is noteworthy that three types of oxidation processes may be occurring during the current study: heating in air, scouring and bleaching, and periodate-driven processes. The first two oxidative processes yield non-specific products, whereas the periodate-driven oxidative products are well-defined in the literature. Thus, a method was needed to gain direct evidence for this postulated cotton oxidation that may be contributing to the bias in the standard oven drying method used to calculate moisture loss in cotton. Thus, this preliminary study employed Attenuated Total Reflectance/Fourier Transform Infrared spectroscopy to determine if direct evidence for oxidation can be observed for oven-treated cotton samples.

Modeling Biased Fineness and Maturity Results

In an earlier paper, our classical models study included simulations to explain the variability in coefficients of determination (R2) between fineness and maturity, micronaire and fineness, and micronaire and maturity of cotton. Subsequently, we emphasized the derivation and testing of three diagnostic models to enhance the R2 and provide information about the analytical quality (accuracy) of the results. In this paper, the theory of biased fineness and maturity measures is introduced and effects on the relationships with micronaire are simulated. Error functions based on Lords micronaire model are derived to express biased results relative to the unbiased values. The simulations include three case studies in order of increasing complexity: bias varies linearly with micronaire, bias is nonlinear with micronaire, and random error is added to the bias. Classical and diagnostic model plots of the simulated unbiased and biased data are presented in detail to readily determine differences in the relationships.

Effects of Mechanical Cleaning on Cotton Fibers: Part III: Effects of Card Wire Condition on White Specks

Combinations of gin and mill cleaning sequences have been studied to determine the best way to clean both smooth-leaf and hairy-leaf cottons. The two varieties were subjected to four different levels of lint cleaning at the gin, followed by nine different mill cleaning sequences, for a total of thirty-six samples. All samples were tested for fiber properties (Part II), yarn strength, and fabric strength and appearance. The yarn and fabric properties are reported in this paper. In the middle of the study, the card wire was damaged and subsequently replaced, which presented the opportunity to determine the impact of the card wires condition on white specks. In addition, image analysis of the fabric samples by Optimas detected the percent white, the percentage of the area of white specks in a specified area of fabric. Because of the variability of white specks, a larger sample size was needed than was available for the mill samples, so only trends can be reported for the mill samples. In general, the more aggressive the cleaning, the higher the percent white. When comparing the effect of ginning, each additional lint cleaner produced an increase in percent white for the worn card wire. The new card wire decreased the percent white overall as compared to the worn card wire. The new card wire samples with three lint cleanings had a significantly higher white speck level than zero, one, or two lint cleaners. Similarly, the harsher the mill cleaning, the higher the percent white. The hairy-leaf variety produced percent white values similar to those for the smooth-leaf cotton for both the old and new card wires. Thus, when confronted with the possibility of a white speck problem, minimal gin cleaning and less aggressive mill cleaning are recommended.

Hydrogen Peroxide Generation of Copper/Ascorbate Formulations on Cotton: Effect on Antibacterial and Fibroblast Activity for Wound Healing Application

Greige cotton (unbleached cotton) is an intact plant fiber that retains much of the outer cotton fiber layers. These layers contain pectin, peroxidases, and trace metals that are associated with hydrogen peroxide (H2O2) generation during cotton fiber development. When greige cotton is subjected to a nonwoven hydroentanglement process, components of the outer cotton fiber layers are retained. When hydrated, this fabric can generate H2O2 (5–50 micromolar). This range has been characterized as inducing accelerated wound healing associated with enhanced cell signaling and the proliferation of cells vital to wound restoration. On the other hand, H2O2 levels above 50 micromolar have been associated with bacteriostatic activity. Here, we report the preparation and hydrogen peroxide activity of copper/ascorbate formulations, both as adsorbed and in situ synthesized analogs on cotton. The cooper/ascorbate-cotton formulations were designed with the goal of modulating hydrogen peroxide levels within functional ranges beneficial to wound healing. The cotton/copper formulation analogs were prepared on nonwoven unbleached cotton and characterized with cotton impregnation titers of 3–14 mg copper per gram of cotton. The copper/ascorbate cotton analog formulations were characterized spectroscopically, and the copper titer was quantified with ICP analysis and probed for peroxide production through assessment with Amplex Red. All analogs demonstrated antibacterial activity. Notably, the treatment of unbleached cotton with low levels of ascorbate (~2 mg/g cotton) resulted in a 99 percent reduction in Klebsiella pneumoniae and Staphylococcus aureus. In situ synthesized copper/ascorbate nanoparticles retained activity and did not leach out upon prolonged suspension in an aqueous environment. An assessment of H2O2 effects on fibroblast proliferation are discussed in light of the copper/cotton analogs and wound healing.