Understanding tribological behavior of complex gel systems for personal care applications using surrogate skin and their bulk rheology

Creams and lotions based on oil-in-water emulsions with polymers are commonly used to treat dry skin conditions. Since the accumulation of traditional surfactants on the skin can promote irritation, an alternative is the use of hydrogenated phosphatidylcholine (HPC), a type of phospholipid that can form a lipid lamellar structure similar to the stratum corneum, the outermost layer of the epidermis which acts as a skin barrier. This research aims to investigate the effect of composition on the rheological and tribological characteristics in systems with HPC as surfactant and to find relationships between rheological and tribological properties to help predicting sensory perception of emulsions for skincare applications. For tribology experiments we used a ball-on-disk configuration to obtain friction curves using different disk materials to mimic the skin surface (PDMS and artificial skin, Bioskin™), while for bulk rheology studies we used dynamic and steady shear experiments. We examine how the addition of different amounts of HPC and polymers with different hydrophobicity affects friction and lubrication regimes from the tribological standpoint and the viscoelasticity, yield stress, and gel formation from the rheological standpoint. The bulk rheology shows that the studied systems are shear thinning and have gel-like behavior. The effect of each component was investigated by going from a simple system (polymer and water) to the more complex system. Systems containing a hydrophobically modified polyacrylic acid lightly crosslinked showed lower yield stresses and lower moduli than systems with carbomer type polymer. Analogous experiments were carried out in tribology. In the range of entrainment speed investigated, the friction coefficients in the boundary regime were lower for diluted systems containing the hydrophobically modified polymer than for systems containing the carbomer type polymer. The Stribeck curves obtained for each of the systems are compared for different polymer types and related to the bulk rheology results to obtain physical insights into these complex systems

Ultralight, reusable biopolymer aerogels: Formation mechanisms to applications in selective fluid sorption and oil spill remediation

Highly porous (99.7 %), ultra-light (4.3 mg/ml) and mechanically robust cellulose ester aerogels with tailored hydrophobicity are synthesized. The aerogels achieve maximum compression strain of 92 % without failure and reach a compressive stress of 350 kPa, which is 100 times higher than that reported for cellulosic aerogels. In its native, unmodified state, the aerogels are hydrophilic and display unprecedented water uptake (45-90 g/g) while affording wet strength. Further adjustment of the aerogels towards hydrophobicity and oleophilicity via chemical vapor deposition with an organo-silane species reveal them to exhibit high oil retention (20-30 g/g aerogel) while maintaining mechanical integrity for fast oil cleanup from aqueous media under marine conditions. The modified aerogels are reusable and durable as they retain their hydrophobicity for months under ambient conditions. The Zisman and Fowkes theoretical frameworks are used to identify the selectiveness of the aerogel and establish a criterion for separation of various non-polar fluids from water media

Self supporting Nanodiamond gels: Elucidating colloidal interactions through rheology

While ND represents a promising class of nanofiller due to its high surface area, superior mechanical strength, optical transparency, tailorable surface functionality and biocompatibility, much remains unknown about the behavior of ND dispersions and their responses to various processing conditions. We hypothesize that controlling interactions in ND dispersions will lead to highly functional systems with tunable modulus and shear response. Steady and dynamic rheology techniques are thus employed to systematically investigate nanodiamonds dispersed in model polar and non-polar media and examine the microstructure and concomitant rheological behavior. We find that low concentrations of ND form gels almost instantaneously in a non-polar media, the strength of which follow a power-law behavior. In contrast, ND’s in polar media show a time-dependent behavior with the modulus increasing with time. We attribute the difference in behavior to variations in inter-particle interactions as well as the interaction of the ND with the media. Large steady and oscillatory strains are applied to ND colloidal gels to investigate the role of shear in gel microstructure breakdown and recovery. For colloidal gels in non-polar medium, the incomplete recovery of elastic modulus at high strain amplitudes indicates dominance of particle-particle interactions; however, in polar media the complete recovery of elastic modulus even at high strain amplitudes indicates dominance of particle-solvent interactions. These results taken together provide a platform to develop self-supporting gels with tunable properties in terms of ND concentration, and solvent ty

Chemical Analysis and Biological Activities of Salvia lavandulifolia Vahl. Essential Oil

Genus Salvia is one of important genera belonging to family lamiaceae. Most of reported biological activities of Salvia usually attributed to its volatile oil. The chemical composition of essential oil from Salvia lavandulifolia was analyzed by GC/MS. A total of sixty seven components were identified in the oil of S. lavandulifolia representing 95.78% of the total oil. β-caryophyllene (11.87%), spathulenol (8.13%), neomenthol (7.75%), pulegone (6.97%), hexadecanoic acid (6.85%), germacrene-D (5.70%), bicyclogermacrene (4.53%), caryophyllene oxide (3.97%) and humulene (3.29%) were found to be the major constituents. The oil showed no antimicrobial and antileishmanial activities in a concentration up to 200 and20 µg/mL, respectively. It displayed a weak antimalarial activity (47 % inhibition) against P. flaciparium.The oil exhibited anti-inflammatory activity adopting iNOS inhibition assay with IC50of 30 µg/mL, but there is no cytotoxicity demonstrated by the oil at tested concentration of 100 µg/mL. Keywords: S. lavandulifolia, essential oil, antimalaria, antimicrobial, antiinflammtory, anticancer

Gene expression of inflammatory markers in adipose tissue between obese women with polycystic ovary and normal obese women

OBJECTIVE: The pathogenesis of polycystic ovary syndrome (PCOS), a common endocrine disease and metabolic disturbance, is still unknown. The aim of the study was to investigate whether patients with PCOS display increased expression of inflammatory markers in adipose tissue. PATIENTS AND METHODS: Two groups of women were investigated, those diagnosed with PCOS (n = 8) and age and BMI-matched normal women (n = 12). Their age was between 20-45 years and all subjects were apparently healthy and did not take any medications. Adipose tissue levels of mRNA of inflammatory markers were determined by use of real-time PCR. RESULTS: There were no differences between obese patients and obese PCOS in levels of adipocytokines. CONCLUSIONS: There were no effects of PCOS on the expression of any of the adipocytokines genes measured in subcutaneous adipose tissue

Excess androgen production in subcutaneous adipose tissue of women with polycystic ovarian syndrome

© 2019 Society for Endocrinology Published by Bioscientifica Ltd. The purpose of this study was to investigate androgen production and the role of insulin and LH in its regulation in subcutaneous adipose tissue (SAT) of women with polycystic ovarian syndrome (PCOS). Protein and mRNA expression of androgen synthesis enzymes (cytochrome P450 17A1 (CYP17A1) and aldo-keto reductase 1C3 (AKR1C3)) were measured in SAT biopsies from women with PCOS, diagnosed according to the Rotterdam criteria (n = 15) and healthy controls (n = 15). Cultured mature adipocytes (differentiated from SAT biopsies) were treated with insulin ± phosphoinositol-3-kinase inhibitor (LY294002) or LH ± insulin. CYP17A1 and AKR1C3 mRNA expression and testosterone concentrations were measured in treated and untreated adipocyte cultures. AKR1C3 mRNA was significantly (P < 0.001) greater in PCOS vs non-PCOS SAT, but CYP17A1 was not significantly different between the two groups. AKR1C3 and CYP17A1 protein expression was not significantly different in PCOS vs non-PCOS SAT. In untreated adipocyte cultures, CYP17A1, AKR1C3 and testosterone levels were significantly higher in the PCOS vs the non-PCOS groups. Addition of insulin increased AKR1C3 mRNA and testosterone levels, but not CYP17A1 mRNA in non-PCOS with no effect on PCOS adipocytes. The stimulatory effects of insulin were not inhibited by LY294002. Addition of LH increased CYP17A1, AKR1C3 and testosterone in non-PCOS adipocytes with no effect in PCOS adipocytes. In conclusion, SAT of women with PCOS produces excess androgen, which may contribute to PCOS-related hyperandrogenaemia. This SAT androgen excess is independent of obesity and is not directly stimulated by inulin or LH

Characterization of Diesel-Hydrogen Peroxide Fuel Blend

In the present work, the outcome of Hydrogen peroxide–diesel fuel blends on the physicochemical properties and kinetic study has been studied. A various blends of diesel-hydrogen peroxide ranging from 5% hydrogen peroxide (H2O2), up to 15% by volume in several fuel blends were experimentally investigated and compared with standard diesel fuel. A new emulsifier has been developed for obtaining better emulsion between diesel and hydrogen peroxide. According to ASTM Standard for fuel tests, the results showed that hydrogen peroxide is capable of enhancing the diesel fuel properties. This is due to the presence of additional oxygen atom within the H2O2 molecule which can enhance the combustion process and ultimately affecting the exhaust emission. Keywords:ASTM test, diesel, hydrogen peroxide, physicochemical properties

The role of oxidative stress in antipsychotics induced ovarian toxicity

This study tested the hypothesis that oxidative stress could be an underlying mechanism for APs-induced ovarian cytotoxicity and reproductive dysfunction. Rat ovarian theca interstitial cells (TICs) were isolated and treated with four APs [chlorpromazine (CPZ), haloperidol (HAL), risperidone (RIS) and clozapine (CLZ)]. MTT assay was used to test the effects of these antipsychotics on TICs viability and to estimate their 50% inhibitory concentrations (IC50s). The effects of APs (IC50s and 1 μM concentrations) on the activities of caspases-3, -8 and -9, reactive oxygen species (ROS) production, total intracellular glutathione and lipid peroxidation (LPO) in TICs were assessed. The effect of antioxidants (reduced glutathione (GSH) and quercetin) on the APs-induced cytotoxicity on TICs was investigated. MTT assay showed all APs to reduce TICs viability. CPZ, HAL and CLZ significantly increased the activity of caspases-3, -8 and -9 (P < 0.0001, < 0.0001 and < 0.01, respectively). All APs at IC50s significantly (P < 0.0001) increased ROS production, decreased total intracellular glutathione and increased LPO. MTT assay in the presence of antioxidants (reduced GSH (5 mM) or quercetin (50 mM)) showed each antioxidant to significantly inhibit the effects of APs at their IC50s on TICs viability. In conclusion, oxidative stress seems to be a possible mechanism for APs-induced ovarian and reproductive toxicity

Insights into patient preferences for elective surgery during the COVID-19 pandemic.

AIMS: To investigate factors that contribute to patient decisions regarding attendance for arthroplasty during the COVID-19 pandemic. METHODS: A postal questionnaire was distributed to patients on the waiting list for hip or knee arthroplasty in a single tertiary centre within the UK. Patient factors that may have influenced the decision to attend for arthroplasty, global quality of life (QoL) (EuroQol five-dimension three-level (EQ-5D-3L)), and joint-specific QoL (Oxford Hip or Knee Score) were assessed. Patients were asked at which 'COVID-alert' level they would be willing to attend an NHS and a "COVID-light" hospital for arthroplasty. Independent predictors were assessed using multivariate logistic regression. RESULTS: Of 540 distributed questionnaires, 400 (74.1%; 236 awaiting hip arthroplasty, 164 awaiting knee arthroplasty) complete responses were received and included. Less than half (48.2%) were willing to attend for hip or knee arthroplasty while a UK COVID-19 epidemic was in circulation (COVID-alert levels 3 to 5). Patients with worse joint-specific QoL had a preference to proceed with surgery at COVID-alert levels 3 to 5 compared to levels 1 and 2 (hip arthroplasty odds ratio (OR) 1.54 (95% confidence interval (CI) 1.45 to 1.63); knee arthroplasty OR 1.16 (1.07 to 1.26)). The odds of patients with worse joint-specific QoL being willing to attend for surgery at COVID-alert levels 3 to 5 increased further if surgery in a private, "COVID-light" hospital was available (hip arthroplasty OR 3.50 (95% CI 3.26 to 3.71); knee arthroplasty OR 1.41 (95% CI 1.29 to 1.53). CONCLUSION: Patient decisions surrounding elective surgery have been influenced by the global COVID-19 pandemic, highlighting the importance of patient involvement in ensuring optimized provision of elective surgery during these challenging times. Cite this article: Bone Jt Open 2021;2(4):261-270