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Objective Isopropyl p-toluenesulfonate ( IPTS) is a potentially genotoxic by-product formed during the esterification of palm oil-based palmitic and palm kernel oil-based myristic acid with isopropanol to produce isopropyl palmitate or isopropyl myristate. There are no methods described for the analysis of IPTS in cosmetic products. In this work, we have established a simple, precise and accurate method to determine the presence and level of IPTS in various finished cosmetic products which contain palm-based esters in their formulations. Methods An Agilent 1200 series high-performance liquid chromatography ( HPLC) unit using a diode-array detector ( DAD) has been employed and optimized to detect IPTS in cosmetic products. For the separation, a reverse-phase Hypersil Gold C8 column (5 μm, 4.6 mm i.d. 250 mm) 5 mM tetrabutylammonium phosphate buffer 50 : 50, (v/v) solution in acetonitrile as mobile phase, in isocratic mode and a flow rate of 0.8 mL min−1 were used. A second method using a gas chromatography/mass selective detector GC- MSD was also developed to confirm the IPTS identity in the cosmetic products. Results Recoveries of IPTS from cosmetic matrices such as a lotion, cleansing milk and a cream ranged from 94.0% to 101.1% with <5% relative standard deviation (% RSD) showing good accuracy and repeatability of the method. The six-point calibration curves (determined over the range 0.5-50 μg mL−1) have a correlation coefficient of 0.9999 (based on HPLC peak area) and 0.9998 (based on HPLC peak height). The intra- and interday precisions (measured by the % RSD) of the method were <2% and <5%, respectively, indicating that the developed method is reliable, precise and reproducible. The detection and quantification limit of the method were found to be 0.5 μg mL−1 and 1.6 μg mL−1, respectively. Analyses of 83 commercial cosmetics showed no presence of IPTS. Conclusions The validation data indicated that this method was suitable for the quantitative analysis of IPTS in commercial cosmetics. This method is applicable for analyses of trace levels of IPTS in cosmetics and has the advantage of using only simple sample preparation steps. [ABSTRACT FROM AUTHOR]

Synopsis A simple and rapid gas chromatography ( GC) method with flame ionization detector was developed for detection of isopropyl para-toluenesulphonate ( IPTS) in palm-based isopropyl palmitate ( IPP) and isopropyl myristate ( IPM). The method involved spiking the IPP/ IPM samples with IPTS and directly injecting the spiked samples into GC without undergoing clean-up steps. The calibration curves for IPTS showed good linearity with coefficient correlation of 0.9999 for six-point calibration from 0.5 to 50 μg mL−1 and 0.9996 for six-point calibration from 0.5 to 200 μg mL−1. IPTS recoveries from IPP were 98.6-103.5% with relative standard deviation ( RSD) of 0.40-2.80%, whereas recoveries from IPM were 97.0-107.2% with RSD of 0.42-4.21%. The identity of IPTS recovered from the isopropyl esters was confirmed by a GC-mass spectrometer detector. The method was successfully applied to the analyses of IPTS in commercial samples. It was found that there were IPTS in the range of 34.8-1303.0 μg g−1 in the palm-based esters for some of the samples analysed. [ABSTRACT FROM AUTHOR]

The article discusses the findings of a study to modify the surface electrical conductivity of poly(ethylene terephthalate) (PET) through titanium plasma immersion. It proposes the use of ion implantation and deposition technique, and demonstrates the Mott hopping model for derivation of conductivity curve as a temperature function. The research confirms evidence of conductivity degradation and an aging effect of the PET after plasma immersion ion implantation.

Presents a one-compartment pharmacokinetic mathematical model to guide factor VIII replacement therapy during active hemorrhage in patients with hemophilia A. Rate of decrease in plasma factor VIII concentrations; Loss of factor VIII through blood loss; Metabolism and elimination of factor VIII.

Surface Young's modulus ( E), hardness ( H), and yield strength ( Y) of zirconia films deposited on Si substrate by filtered cathodic vacuum arc (FCVA) under different oxygen flow rate were studied by nano-indentation measurement and finite element modeling. Identified by X-ray diffraction, the structure of the films evolves from amorphous to monoclinic, and then to amorphous, with oxygen flow rate increasing from 10 to 80 standard cubic centimeters per minute, which affects the mechanical properties of the films. It is found that the elastic–perfect-plastic constitutive model is successfully applied to the films with amorphous structure; however inadequate for the monoclinic ZrO2, indicating that dislocation-related plasticity possibly occurs during nano-indentation. [ABSTRACT FROM AUTHOR]

Background: Major society guidelines recommend the fibrosis-4 index (FIB-4) as the initial step to risk stratifying people with metabolic dysfunction-associated steatotic liver disease (MASLD). We aimed to evaluate the proportion of people with MASLD-related hepatocellular carcinoma (HCC) and a low FIB-4., Methods: This cohort study included 613 consecutive adults (33% female) diagnosed with MASLD-related HCC from January 2008 to August 2023 at seven international centres in Australia, India, Japan, South Korea, Singapore and the United States. The primary objective was to determine the proportion of participants with a low FIB-4, defined as FIB-4 < 1.3, or < 2 if age > 65 years, in people without cirrhosis., Results: The mean (±SD) age and body mass index were 71 (±11) years and 27 (±7) kg/m 2 , respectively. Overall, 235 participants (38%) did not have known cirrhosis. The median FIB-4 was 3.90 (IQR 2.42-6.42). A total of 78 participants (13%) had a low FIB-4. Among participants without known cirrhosis (n = 235), 62 participants (26%) had a low FIB-4. Participants with a low FIB-4 had larger median total tumour diameter (p < 0.001) and lower median serum alpha-fetoprotein (p = 0.005), compared to participants without a low FIB-4. Cirrhosis was associated with lower odds of low FIB-4, but not other factors such as male sex, type 2 diabetes, or obesity., Conclusion: More than a quarter of those with MASLD-related HCC without cirrhosis have a low FIB-4. The proposed clinical care pathways may not identify these people for further evaluation., (© 2024 John Wiley & Sons Ltd.)