Forensic pilot application of rehydrating solutions on human cadaveric skin: what are the effects on hemorrhagic infiltrates?

The microscopic evaluation of hemorrhagic infiltrates is crucial in forensic diagnostics, but it proves challenging in corificated and mummified cadavers. In these cases, pre-treatment with rehydrating solutions is recommended, although their effects on the hemorrhagic infiltrate are not well understood. In this pilot study, we microscopically investigated the effect of two different rehydrating solutions-Sandison's solution and fabric softener-on well-preserved human cadaveric skin samples taken from areas affected by an ecchymotic lesion, comparing them with direct fixation in formalin. Specifically, we examined the topographic distribution of the hemorrhagic infiltrate in each layer of the skin by assigning a semi-quantitative score, conducted mutual comparisons, and performed statistical analysis. Histologically, compared to direct fixation in formalin, a slight and statistically non-significant reduction in the hemorrhagic infiltrate was observed in samples pre-treated with fabric softener. On the other hand, a more pronounced and statistically significant decrease in scores was observed in samples pre-treated with Sandison's solution. This effect is likely due to the fact that Sandison's solution, due to its components, exerts an osmotic effect, partially inducing osmotic lysis of red blood cells. Overall, extensive areas of hemorrhagic infiltrates were preserved, although to a lesser extent, while smaller foci were markedly reduced, sometimes even disappearing. The findings suggest that Sandison's solution has a detrimental effect on cutaneous hemorrhagic infiltrates, emphasizing the importance of being cautious and conducting dual sampling, using both formalin and a rehydrating solution, for forensic examination of mummified or corificated skin samples.

Technical note: A comparison between rehydrating solutions in the pretreatment of mummified and corified skin for forensic microscopic examination.

Microscopic examination of mummified or corified skin may be of extreme importance for forensic purposes. However, standard histological samples in these cases are low-end, and preparation is burdened by several problems and so are diagnostic results: an improvement of these types of specimens is therefore advantageous. This study aims to identify the best performing rehydration solution among a fabric softener, a body lotion, and Sandison's rehydrating solution. Samples of skin undergoing mummification or corification were collected from 25 corpses and each sample was divided into 4 fragments: one of these fragments was directly fixated in 4% formalin, one was previously treated with a tissue softener, another one was previously treated with a body lotion, and the last one was treated with Sandison's solution. After 72 h, the pretreated samples were post-fixated in 4% formalin and then prepared for standard histological examination staining the histological slides with hematoxylin-eosin and Masson's trichrome. At the microscopic examination, samples directly fixated in formalin were characterized by usual marked structural alterations and altered stainability, typical of such dry tissues. Vice versa, those previously treated appeared to be better-preserved even though with different improvement levels: body lotion made a medium-low-grade restoration of the tissues, and fabric softener a high-grade restoration, while Sandison's rehydrating solution produced an optimal grade restoration. Sandison's rehydrating solution was confirmed to be the best rehydrating substance for mummified and corified skin. Fabric softener could be, however, considered a valid substitute, being productive of high-grade microscopic yield.

Elucidation of Softening Mechanism in Rinse Cycle Fabric Softeners. Part 1: Effect of Hydrogen Bonding.

Most softening agents, such as rinse cycle fabric softeners, used by consumers at home contain cationic surfactants that have two long alkyl chains as their main component. The softening mechanism on fibers, especially cotton, has not yet been scientifically established, despite the market prevalence of fabric softeners for decades. One explanation for the softening effect is that the friction between fibers is reduced. According to this explanation, the fiber surfaces are coated by layers of alkyl chains. Because of the low coefficient of friction between alkyl chain layers of low surface energy, the fibers easily slide against one another yielding softer cotton clothing. However, no direct scientific evidence exists to prove the validity of this explanation. The softening mechanism of cotton yarn is discussed in this paper. Bending force values of cotton yarn treated with several concentrations of softener are measured by bend testing, and cotton and polyester yarns are compared. Results indicate that increases in cotton yarn hardness after natural drying are caused by cross-linking among inner fibers aided by bound water. This type of bound water has been known to exist even after 2 days of drying at 25 °C and 60 % relative humidity. Yarn dried in vacuo is soft, similar to that treated with softener. Thus, some of the softening effect caused by fabric softeners on cotton can be attributed to the prevention of cross-linking by bound water between cotton fibers.

Elucidation of Softening Mechanism in Rinse-Cycle Fabric Softeners. Part 2: Uneven Adsorption-The Key Phenomenon to the Effect of Fabric Softeners.

We investigated the actual factor determining the softening effect of a fabric softener. The adsorption area of the softener on model cotton cloths and yarns was identified using bromophenol blue. There was almost no softener at the cross-points of the yarns in the cloth samples or in the inner part of the yarns. The softening performance was better when there was less softener at the cross-points of the yarns than when the yarns were evenly covered by the softener. Thus we conclude that the presence of softener at the cross-points of yarns is not a vital factor in the softening effect. In addition, more softener was found on the outer part of the yarn than the inner part, indicating gradation in the adsorption pattern of the softener. Thus, we propose that more softener is adsorbed on the exposed part of the yarn in a cloth, and the formation of a hydrogen-bonding network containing bound water is inhibited, thus softening the outer part of the yarn. However, the presence of a small amount of softener in the inner part of the yarn preserves the hydrogen-bonding network. Favorable elasticity, or bounce, of the yarns and cloth is realized when an appropriate amount of softener is used. Excess softener would reach the inner part of the yarn, reducing the diameter of the core part of the yarn, making the cloth appear wilted.

Triethanolamine-based esterquat in sediments: New analytical method, environmental occurrence, and homologue composition.

The cationic surfactant triethanolamine-based esterquat (TEAQ) is a main ingredient in commercial fabric softeners and is produced and used in large quantities. However, little information is available for its occurrence in the environment, particularly in sediments. Here, we developed an analytical method for quantifying TEAQ in sediment and investigated TEAQ contamination in Japanese river and lake sediments. In our analytical method, TEAQ concentrations were measured by liquid chromatography-tandem mass spectrometry using a polymer-based size-exclusion column, which resulted in excellent peak shapes. TEAQ was detected at significant levels in procedural blanks, resulting in a method limit of detection in the sediment of 8.9-97 µg/kg-dry for TEAQ monoesters and 0.6-24 µg/kg-dry for TEAQ diesters. TEAQ was detected in 22 out of 26 sediment samples, with the sum of all homologue concentrations being up to 1340 µg/kg-dry. The concentration of TEAQ in sediments was high at locations where the concentrations of benzalkoniums and the organic carbon content were also high. TEAQ was detected in 8 out of 14 commercial fabric softeners at concentrations of 1.7-7.4 wt%. TEAQ homologues containing only saturated fatty acids accounted for 83 ± 5% of the total TEAQ in the sediments, whereas those with unsaturated fatty acids accounted for 71 ± 14% of the total TEAQ in a commercial technical mixture and the softener products. The results of this study will be useful for the environmental risk assessment of esterquats.

Development of a rapid screening method utilizing 2D LC for effect-directed analysis in the identification of environmental toxicants.

Effect-directed analysis (EDA) is a crucial tool in environmental toxicology, effectively integrating toxicity testing with chemical analysis. The conventional EDA approach, however, presents challenges such as significant solvent consumption, extended analysis time, labor intensity, and potential contamination risks. In response, we introduce an innovative alternative to the conventional EDA. This method utilizes the MTT bioassay and online two-dimensional liquid chromatography (2D LC) coupled with high-resolution mass spectrometry (HR-MS), significantly reducing the fractionation steps and leveraging the enhanced sensitivity of the bioassay and automated chemical analysis. In the chemical analysis phase, a switching valve interface is employed for comprehensive analysis. We tested the performance of both the conventional and our online 2D LC-based methods using a household product. Both methods identified the same number of toxicants in the sample. Our alternative EDA is 22.5 times faster than the conventional method, fully automated, and substantially reduces solvent consumption. This novel approach offers ease, cost-effectiveness, and represents a paradigm shift in EDA methodologies. By integrating a sensitive bioassay with online 2D LC, it not only enhances efficiency but also addresses the challenges associated with traditional methods, marking a significant advancement in environmental toxicology research.

Electrokinetic investigation of deposition of cationic fabric softener vesicles on anionic porous cotton fabrics.

HYPOTHESIS: Colloidal deposition on porous substrates is a complex process influenced by both, (i) characteristics of colloidal permeation into porous substrates, and (ii) mechanism of colloidal deposition on solid surfaces. Such processes are quintessential to action of products such as hair conditioners and fabric softeners where the substrates to be treated are porous. The performance of these formulations is linked with the distribution of deposited colloids across porous substrates i.e. whether deposition is localized near substrate periphery, or deposition is homogeneously distributed. EXPERIMENTS: In this work, we investigate the deposition of cationic vesicles, commonly used in fabric softeners, on anionic porous cotton yarns via spectrophotometric measurement of adsorption density of vesicles on yarns and electrokinetic measurement of cotton yarn apparent zeta potentials. Under the employed conditions, cotton yarn apparent zeta potentials are sensitive predominantly to external yarn surfaces. Therefore, these measurements can distinguish between deposition on external and internal yarn surfaces. FINDINGS: The phase behavior of lipid bilayers constituting the vesicles is identified as an important governing factor with solid-gel vesicles depositing more near yarn periphery, and liquid-crystalline vesicles depositing more uniformly throughout the yarns. Bulk electrical conductivity also influences the distribution of deposited vesicles. The results are explained with the help of a newly proposed theory.

Small Angle X-ray Scattering and Electron Spin Resonance Spectroscopy Study on Fragrance Infused Cationic Vesicles Modeling Scent-Releasing Fabric Softeners.

Industrially relevant systems for household and personal-care products often involve a large number of components. Such multiple component formulations are indispensable and effective for functionalization of the products, but may simultaneously provide more complex structural features compared to those in ideal systems comprising a smaller number of highly pure substances. Using cryogenic transmission electron microscopy (cryo-TEM), small angle X-ray scattering (SAXS), and electron spin resonance (ESR) spectroscopy, we have investigated effects of fragrance-incorporation into cationic vesicles on their bilayer structures and membrane-membrane interactions. Cationic vesicles were prepared from TEQ surfactant, whose major component was di(alkyl fatty ester) quaternary ammonium methosulfate, and fragrance components, l-menthol, linalool, and d-limonene, were infused into the vesicle membranes to model scent-releasing fabric softeners. The cryo-TEM images confirm formation of multilamellar vesicles (MLVs). Generalized indirect Fourier transformation (GIFT) analysis of the SAXS intensities based on the modified Caillé structure factor model reveals that incorporation of a more hydrophobic fragrance component leads to a more pronounced increase of the surface separation (water layer thickness). Furthermore, the fragrance-infused systems show longer-range order of the bilayer correlations and enhanced undulation fluctuation of the membranes than those in the TEQ alone system. The spin-label ESR results indicate different restricted molecular motions in the TEQ bilayers depending on the labeled position and their marked changes upon addition of the fragrance components, suggesting different mixing schemes and solubilization positions of the fragrance molecules in the TEQ bilayers. The present data have demonstrated how the infused fragrance molecules having different hydrophobicity and molecular architectures into the cationic vesicles affect the membrane structures and the intermembrane interactions, which may provide useful information for precisely controlling a fragrance-releasing property.

Intact deposition of cationic vesicles on anionic cellulose fibers: Role of vesicle size, polydispersity, and substrate roughness studied via streaming potential measurements.

HYPOTHESIS: Understanding the mechanism of intact vesicle deposition on solid surfaces is important for effective utilization of vesicles as active ingredient carriers in applications such as drug delivery and fabric softening. In this study, the deposition of large (davg=12µm) and small (davg=0.27µm) cationic vesicles of ditallowethylester dimethylammonium chloride (DEEDMAC) on smooth and rough anionic cellulose fibers is investigated. EXPERIMENTS: The deposition process is studied quantitatively using streaming potential measurements and spectrophotometric determination of DEEDMAC concentrations. Natural and regenerated cellulose fibers, namely cotton and viscose, having rough and smooth surfaces, respectively, are used as adsorbents. Equilibrium deposition data and profiles of substrate streaming potential variation with deposition are used to gain insights into the fate of vesicles upon deposition and the deposition mechanism. FINDINGS: Intact deposition of DEEDMAC vesicles is ascertained based on streaming potential variation with deposition in the form of characteristic saturating profiles which symbolize particle-like deposition. The same is also confirmed by confocal fluorescence microscopy. Substrate roughness is found to considerably influence the deposition mechanism which, in a novel application of electrokinetic methods, is elucidated via streaming potential measurements.

Candida and Fusarium species known as opportunistic human pathogens from customer-accessible parts of residential washing machines.

Energy constraints have altered consumer practice regarding the use of household washing machines. Washing machines were developed that use lower washing temperatures, smaller amounts of water and biodegradable detergents. These conditions may favour the enrichment of opportunistic human pathogenic fungi. We focused on the isolation of fungi from two user-accessible parts of washing machines that often contain microbial biofilms: drawers for detergents and rubber door seals. Out of 70 residential washing machines sampled in Slovenia, 79% were positive for fungi. In total, 72 strains belonging to 12 genera and 26 species were isolated. Among these, members of the Fusarium oxysporum and Fusarium solani species complexes, Candida parapsilosis and Exophiala phaeomuriformis represented 44% of fungi detected. These species are known as opportunistic human pathogens and can cause skin, nail or eye infections also in healthy humans. A machine learning analysis revealed that presence of detergents and softeners followed by washing temperature, represent most critical factors for fungal colonization. Three washing machines with persisting malodour that resulted in bad smelling laundry were analysed for the presence of fungi and bacteria. In these cases, fungi were isolated in low numbers (7.5 %), while bacteria Micrococcus luteus, Pseudomonas aeruginosa, and Sphingomonas species prevailed.