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ACS Sustainable Chemistry & Engineering May 2024Herein we address the efficiency of the CO sorption of ionic liquids (IL) with hydrogen bond donors (e.g., glycols) added as viscosity modifiers and the impact of...
Herein we address the efficiency of the CO sorption of ionic liquids (IL) with hydrogen bond donors (e.g., glycols) added as viscosity modifiers and the impact of encapsulating them to limit sorbent evaporation under conditions for the direct air capture of CO. Ethylene glycol, propylene glycol, 1,3-propanediol, and diethylene glycol were added to three different ILs: 1-ethyl-3-methylimidazolium 2-cyanopyrrolide ([EMIM][2-CNpyr]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF]), and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF]). Incorporation of the glycols decreased viscosity by an average of 51% compared to bulk IL. After encapsulation of the liquid mixtures using a soft template approach, thermogravimetric analysis revealed average reductions in volatility of 36 and 40% compared to the unencapsulated liquid mixtures, based on 1 h isothermal experiments at 25 and 55 °C, respectively. The encapsulated mixtures of [EMIM][2-CNpyr]/1,3-propanediol and [EMIM][2-CNpyr]/diethylene glycol exhibited the lowest volatility (0.0019 and 0.0002 mmol/h at 25 °C, respectively) and were further evaluated as CO absorption/desorption materials. Based on the capacity determined from breakthrough measurements, [EMIM][2-CNpyr]/1,3-propanediol had a lower transport limited absorption rate for CO sorption compared to [EMIM][2-CNpyr]/diethylene glycol with 0.08 and 0.03 mol CO/kg sorbent, respectively; however, [EMIM][2-CNpyr]/diethylene glycol capsules exhibited higher absorptions capacity at ∼500 ppm of CO (0.66 compared to 0.47 mol of CO/kg sorbent for [EMIM][2-CNpyr]/1,3-propanediol). These results show that glycols can be used to not only reduce IL viscosity while increasing physisorption sites for CO sorption, but also that encapsulation can be utilized to mitigate evaporation of volatile viscosity modifiers.
PubMed: 38783843
DOI: 10.1021/acssuschemeng.4c01265 -
Contact Dermatitis May 2024Chemical hair relaxers are widely utilized by black women, yet little research exists on the allergens present in these products.
BACKGROUND
Chemical hair relaxers are widely utilized by black women, yet little research exists on the allergens present in these products.
OBJECTIVE
This study aims to investigate allergen prevalence in the most popular chemical hair relaxers.
METHODS
We analysed 41 products from five major retailers, identifying allergens through ingredient lists and comparing them to the 2020 American Contact Dermatitis Group Core allergen series.
RESULTS
The most common contact allergens in chemical relaxers include propylene glycol, cetyl steryl alcohol, fragrance, D/L-a-tocopherol, tea tree oil and cocamidopropyl betaine.
CONCLUSION
Understanding allergen exposure in products used by individuals with textured hair is needed for managing contact dermatitis in diverse populations. This analysis underscores the presence of potential allergens in hair relaxers, emphasizing the importance of dermatologists' awareness and patient scrutiny of ingredient lists.
PubMed: 38783163
DOI: 10.1111/cod.14583 -
Journal of the American Society For... Jun 2024We investigated the applicability of proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) for quantitative analysis of mixtures comprising glycerin,...
We investigated the applicability of proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) for quantitative analysis of mixtures comprising glycerin, acetol, glycidol, acetaldehyde, acetone, and propylene glycol. While PTR-TOF-MS offers real-time simultaneous determination, the method selectivity is limited when analyzing compounds with identical elemental compositions or when labile compounds present in the mixture produce fragments that generate overlapping ions with other matrix components. In this study, we observed significant fragmentation of glycerin, acetol, glycidol, and propylene glycol during protonation via hydronium ions (HO). Nevertheless, specific ions generated by glycerin (/ 93.055) and propylene glycol (/ 77.060) enabled their selective detection. To thoroughly investigate the selectivity of the method, various mixtures containing both isotope-labeled and unlabeled compounds were utilized. The experimental findings demonstrated that when samples contained high levels of glycerin, it was not feasible to perform time-resolved analysis in HO mode for acetaldehyde, acetol, and glycidol. To overcome the observed selectivity limitations associated with the HO reagent ions, alternative ionization modes were investigated. The ammonium ion mode proved appropriate for analyzing propylene glycol (/ 94.086) and acetone (/ 76.076) mixtures. Concerning the nitric oxide mode, specific / were identified for acetaldehyde (/ 43.018), acetone (/ 88.039), glycidol (/ 73.028), and propylene glycol (/ 75.044). It was concluded that considering the presence of multiple product ions and the potential influence of other compounds, it is crucial to conduct a thorough selectivity assessment when employing PTR-TOF-MS as the sole method for analyzing compounds in complex matrices of unknown composition.
Topics: Mass Spectrometry; Volatile Organic Compounds; Electronic Nicotine Delivery Systems; Nicotiana; Propylene Glycol; Acetaldehyde; Acetone; Glycerol; Hot Temperature; Epoxy Compounds; Propanols
PubMed: 38780179
DOI: 10.1021/jasms.4c00062 -
F1000Research 2024Curcumin, known for its anti-inflammatory properties, was selected for the developing consumer friendly film forming spray that offers precise delivery of curcumin and...
BACKGROUND
Curcumin, known for its anti-inflammatory properties, was selected for the developing consumer friendly film forming spray that offers precise delivery of curcumin and and improves patient adherence.
METHODS
An optimized film-forming solution was prepared by dissolving curcumin (1%), Eudragit RLPO (5%), propylene glycol (1%), and camphor (0.5%) in ethanol: acetone (20:80) as the solvent. The solution was filled in a spray container which contained 70% solutions and 30% petroleum gas. characterization was performed.
RESULTS
Potential anti-inflammatory phytoconstituents were extracted from the PubChem database and prepared as ligands, along with receptor molecules (nsp10-nsp16), for molecular docking using Autodock Vina. The docking study showed the lowest binding energy of -8.2 kcal/mol indicates better binding affinities. The optimized formulation consisted of ethanol:acetone (20:80) as the solvent, Eudragit RLPO (5%) as the polymer, propylene glycol (1%) as the plasticizer, and camphor oil (0.5%) as the penetration enhancer. The optimized formulation exhibited pH of 5.8 ± 0.01, low viscosity, low film formation time (19.54 ± 0.78 sec), high drug content (8.243 ± 0.43 mg/mL), and extended drug permeation (85.08 ± 0.09%) for nine hours. Consequently, the formulation was incorporated into a container using 30% liquefied petroleum gas, delivering 0.293 ± 0.08 mL per actuation, containing 1.53 ± 0.07 mg of the drug. The film-forming spray exhibited higher cumulative drug permeation (83.94 ± 0.34%) than the marketed cream formulation and pure drug solution after 9 h, with an enhancement ratio of 14. Notably, the film-forming spray exhibited no skin irritation and remained stable for over three months.
CONCLUSIONS
The developed curcumin film-forming system is promising as a carrier for wound management because of its convenient administration and transport attributes. Further studies are required to validate its efficacy in wound management.
Topics: Curcumin; Humans; Administration, Topical; Molecular Docking Simulation; Skin Absorption
PubMed: 38779313
DOI: 10.12688/f1000research.142860.1 -
Chemical Research in Toxicology Jun 2024Electronic (e-) cigarette formulations containing nicotine salts from a range of organic acid conjugates and pH values have dominated the commercial market. The acids in...
Electronic (e-) cigarette formulations containing nicotine salts from a range of organic acid conjugates and pH values have dominated the commercial market. The acids in the nicotine salt formulations may alter the redox environment in e-cigarettes, impacting free radical formation in e-cigarette aerosol. Here, the generation of aerosol mass and free radicals from a fourth-generation e-cigarette device was evaluated at 2 wt % nicotine salts (pH 7, 30:70 mixture propylene glycol to vegetable glycerin) across eight organic acids used in e-liquids: benzoic acid (BA), salicylic acid (SLA), lactic acid (LA), levulinic acid (LVA), succinic acid (SA), malic acid (MA), tartaric acid (TA), and citric acid (CA). Furthermore, 2 wt % BA nicotine salts were studied at the following nicotine to acid ratios: 1:2 (pH 4), 1:1 (pH 7), and 2:1 (pH 8), in comparison with freebase nicotine (pH 10). Radical yields were quantified by spin-trapping and electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra of free radicals in the nicotine salt aerosol matched those generated from the Fenton reaction, which are primarily hydroxyl (OH) radicals and other reactive oxygen species (ROS). Although the aerosol mass formation was not significantly different for most of the tested nicotine salts and acid concentrations, notable ROS yields were observed only from BA, CA, and TA under the study conditions. The e-liquids with SLA, LA, LVA, SA, and MA produced less ROS than the 2 wt % freebase nicotine e-liquid, suggesting that organic acids may play dual roles in the production and scavenging of ROS. For BA nicotine salts, it was found that the ROS yield increased with a higher acid concentration (or a lower nicotine to acid ratio). The observation that BA nicotine salts produce the highest ROS yield in aerosol generated from a fourth-generation vape device, which increases with acid concentration, has important implications for ROS-mediated health outcomes that may be relevant to consumers, manufacturers, and regulatory agencies.
Topics: Electronic Nicotine Delivery Systems; Nicotine; Free Radicals; Vaping; Salts; Solutions; Benzoic Acid; Levulinic Acids; Malates
PubMed: 38778043
DOI: 10.1021/acs.chemrestox.4c00065 -
Journal of Medical Entomology May 2024Propylene glycol (PG) demonstrates greater efficacy than other sugar polyols. However, the attributes it confers for toxicity and possible co-formulation with other...
Fatally impaired glucose digestion by propylene glycol in Aedes aegypti (Diptera: Culicidae) and co-formulation with terpenoids for enhancing attractive toxic sugar baits.
Propylene glycol (PG) demonstrates greater efficacy than other sugar polyols. However, the attributes it confers for toxicity and possible co-formulation with other ingredients are unknown. To evaluate this, α-glucosidase and glucose oxidase reactions were performed in Aedes aegypti (L.) (Diptera: Culicidae) to categorize if PG behaves similarly to prior studied sugar alcohols. A combination of no-choice and choice assays was used to determine effective ratios of PG and sucrose, competitiveness against a control of 10% sucrose, and whether mosquitoes recovered from PG consumption. The final trials included β-cyclodextrin encapsulated cinnamon leaf oil, clove stem oil, patchouli oil, garlic oil, cedarwood oil, and papaya seed oil formulated with 5% sucrose + 5% PG. PG functioned as a linear competitive inhibitor of α-glucosidase. The efficacy of PG was synergized by co-ingestion with equivalent ratios of sucrose. Unlike the high diuretic response to other sugar alcohols, PG resulted in diminished excretion regardless of being co-formulated with sucrose or terpenoids. PG is not especially competitive against unadulterated sugar meals but is likewise not clearly repellent. Although mosquitoes did not recover from ingestion of the glycol meals, there was no indication that mortality would continue to accumulate once the treatments were removed. Of the terpenoids tested, cinnamon and patchouli caused ~50% or less mortality; garlic, cedarwood, and clove caused 80-90% mortality; and papaya seed caused 100% mortality, exceeding all other test groups and the formulation blank. PG is a useful supporting ingredient in attractive toxic sugar bait formulations with flexibility in formulation.
PubMed: 38767975
DOI: 10.1093/jme/tjae068 -
BioRxiv : the Preprint Server For... May 2024Adolescent drug exposure has been associated with more severe mental health outcomes related to substance abuse and anxiety disorders. The aim of the present study was...
Adolescent drug exposure has been associated with more severe mental health outcomes related to substance abuse and anxiety disorders. The aim of the present study was to contrast the long-term effects of repeated heroin vapor inhalation during adolescence with similar heroin exposure in adulthood. Groups of female Wistar rats underwent twice daily 30-minute sessions of heroin or propylene glycol (control) vapor inhalation from postnatal days (PND) 36-45 or PND 85-94, respectively. Nociception was assessed after vapor inhalation sessions and forty days later, for the Adolescent-Exposed and Adult-Exposed groups. Anxiety-like behavior was assessed with an elevated plus-maze (EPM) and spatial learning was assessed with a Barnes maze. Acute effects of naloxone (0.3 mg/kg, i.p.) and heroin (0.5 and 1.0 mg/kg, s.c.) on thermal nociception were determined on PND 140/189 and PND 149/198, respectively. Repeated heroin vapor inhalation produced anti-nociceptive tolerance across sessions in both adolescent and adult rats, with the adolescents exhibiting more complete tolerance. Heroin vapor inhalation produced anxiolytic effects, regardless of age of exposure. There were no effects of heroin on spatial learning. Naloxone produced acute hyperalgesia in all but the Adolescent-Exposed heroin group, and heroin anti-nociception was blunted in both heroin-exposed groups at the highest heroin dose. Repeated heroin vapor inhalation can produce lasting effects on nociception and anxiety-like behavior that persist for months after the exposure. Importantly, these findings suggest that adolescent exposure to heroin vapor produces specific effects on nociception that are not observed when exposure occurs in adulthood.
PubMed: 38765990
DOI: 10.1101/2024.05.06.592492 -
Neuropsychological Rehabilitation May 2024Systematic exposure to odours (olfactory training, OT) is a method of smell loss treatment. Due to olfactory system projections to prefrontal brain areas, OT has been...
Systematic exposure to odours (olfactory training, OT) is a method of smell loss treatment. Due to olfactory system projections to prefrontal brain areas, OT has been hypothesized to enhance cognitive functions, but its effects have been studied predominantly in adults. This study tested OT effects on working memory (WM), i.e., the ability to store and manipulate information for a short time, in healthy children aged 6-9 years. We expected OT to improve olfactory WM and establish cross-modal transfer to visual and auditory WM. Participants performed 12 weeks of bi-daily OT with either 4 odours (lemon, eucalyptus, rose, cloves; OT group) or odourless propylene glycol (placebo group). Pre- and post-training, participants' WM was measured utilizing odours (olfactory WM) or pictures (visual WM) and a word-span task (auditory WM). 84 children (40 girls) completed the study. The analyses revealed no changes in the WM performance following OT. The olfactory WM task was the most difficult for children, highlighting the need to include olfactory-related tasks in educational programmes to improve children's odour knowledge and memory, just as they learn about sounds and pictures. Further neuroimaging research is needed to fully understand the impact of OT on cognitive functions in children.
PubMed: 38762780
DOI: 10.1080/09602011.2024.2343484 -
Journal of the American College of... Jun 2024Propylene glycol (PG) is a diol (a double alcohol) that is commonly used as a food additive to preserve shelf life and enhance flavors, texture, and appearance. Although...
Propylene glycol (PG) is a diol (a double alcohol) that is commonly used as a food additive to preserve shelf life and enhance flavors, texture, and appearance. Although PG makes up only a small percentage of cornstarch, ingestion of large doses can cause lactic acidosis leading to hyperosmolarity, high anion gap metabolic acidosis (HAGMA), and a sepsis-like syndrome. A 17-year-old female presented to our emergency department (ED) with chronic chest pain, dyspnea, nausea, and vomiting. Laboratory testing showed an elevated anion gap of 18 mEq/L with no osmolar gap. Toxicology screening was negative. Twelve hours after ED arrival, she admitted to consuming one box of cornstarch daily for the past 6 months. She was admitted to the intensive care unit (ICU) with multisystem organ failure due to propylene glycol toxicity. After empiric treatment with fomepizole and continuous renal replacement therapy, her clinical status gradually improved. This case highlights the importance of obtaining a thorough dietary history in patients with suspected toxicities, especially when laboratory values demonstrate an unexplained HAGMA and/or lactic acidosis. Prompt recognition and therapeutic intervention with fomepizole, a potent inhibitor of alcohol dehydrogenase, is essential in reducing life-threatening sequelae following toxic alcohol ingestions.
PubMed: 38756767
DOI: 10.1002/emp2.13188 -
Chembiochem : a European Journal of... May 2024Natural and pure p-coumaric acid has valuable applications, and it can be produced via bioprocessing. However, fermentation processes have so far been unable to provide...
Natural and pure p-coumaric acid has valuable applications, and it can be produced via bioprocessing. However, fermentation processes have so far been unable to provide sufficient production metrics, while a biocatalytic process decoupling growth and production historically showed much promise. This biocatalytic process is revisited in order to tackle product inhibition of the key enzyme tyrosine ammonia lyase. In situ product removal is proposed as a possible solution, and a polymer/salt aqueous two-phase system is identified as a suitable system for extraction of p-coumaric acid from an alkaline solution, with a partition coefficient of up to 13. However, a 10 % salt solution was found to reduce tyrosine ammonia lyase activity by 19 %, leading to the need for a more dilute system. The cloud points of two aqueous two-phase systems at 40 °C and pH 10 were found to be 3.8 % salt and 9.5 % polymer, and a 5 % potassium phosphate and 12.5 % poly(ethylene glycol-ran-propylene glycol) mW~2500 system was selected for in situ product removal. An immobilized tyrosine ammonia lyase biocatalyst in this aqueous two-phase system produced up to 33 g/L p-coumaric acid within 24 hours, a 1.9-fold improvement compared to biocatalysis without in situ product removal.
PubMed: 38742869
DOI: 10.1002/cbic.202400178