Glycerol Research Articles

Enhancing Healing of Infected Wounds with Glycerin‐Modified Sodium Alginate/Silk Sericin Composite Film Functionalized with Polygonatum sibiricum Polysaccharide‐Capped Silver Nanoparticles

AbstractA sodium alginate/silk sericin (SA/SS) film was modified with glycerin (GI) and Polygonatum sibiricum polysaccharide@silver nanoparticles (PSP@AgNPs) to create a SA/SS/GI/PSP@AgNP composite film with antibacterial and antioxidant properties. The physicochemical properties of the SA/SS/GI/PSP@AgNP composite film were analyzed, and its cytocompatibility, antioxidant activity, and antibacterial properties were investigated. The optimum conditions for the preparation of the SA/SS/GI/PSP@AgNP composite film were 2 % SA, 2 % SS, 20 % GI, and 40 μg/mL of PSP@AgNPs. The addition of GI improved the surface smoothness of the composite films, while the presence of PSP@AgNPs did not significantly alter it. Spectroscopic characterization demonstrated that GI and PSP@AgNPs were physically bound to SA/SS. Approximately 53 % of the PSP@AgNP was released from the SA/SS/GI/PSP@AgNP composite film over 24 h of soaking in aqueous solution. The resulting leaching solution did not cause hemolysis or cytotoxicity, indicating its biocompatibility. Additionally, the SA/SS/GI/PSP@AgNP composite film exhibited strong antioxidant and antibacterial properties, and it promoted healing of mouse wounds infected with Staphylococcus aureus.

Energy storage application of plasticized biopolymer blend electrolyte doped with ammonium nitrate as H+ provider

Recently, proton-conducting electrolytes for energy storage purposes attracted the focus of many research groups as possible alternatives for Li-based energy storage applications. Natural polymers offer a promising solution to counter the environmental impact of synthetic polymers. In this work proton conducting CS:POZ based natural polymer electrolytes were plasticized with glycerol (GL) to improve the ion conductivity and increase the free ion percentage. The films of CS:POZ:NH4NO3 electrolyte were prepared using the casting technique. The plasticizers were changed from 9 to 36 wt%. The FTIR method revealed ion interaction among polymer, salt, and plasticizer. The deconvolution of FTIR band associated with NO3 anion was used to calculate the ion transport parameters (ITPs). It was found that the free ion contour area was enhanced by increasing plasticizer concentration. The EIS plot fitted with equivalent circuit elements was used to determine the DC conductivity and ITPs. The dominancy of ion species was examined using TNM measurement. The safety region for energy storage device (ESD) application was found from the LSV examination. The activated carbon was used to manufacture the electrodes for ESD application. The cyclic voltammetry (CV) investigation found that the capacitances of the ESD influenced by scan rates.

An experimental investigation of PG/VG pyrolysis combined with molecular dynamics

Propylene glycol (PG) and vegetable glycerin (VG) are common ingredients used in the preparation of various products, and notably in e-cigarette liquids. In this work, we investigated the generation of light gases from the pyrolysis of PG, VG and their mixtures. ReaxFF-MD was used to study the elementary reactions involved in the pyrolysis of PG/VG mixtures of 50/50 and 30/70 percent by volume. Main reactions included dehydration, dehydrogenation and C-C bond cleavage. In addition, we focused on the elementary reactions that form the light gases: C2 hydrocarbons, CO, CO2, and H2. Kinetic rates of PG and VG decomposition, and the Arrhenius parameters, were calculated, with errors as low as 1% with respect to pure PG and VG kinetic rate constants. Furthermore, experimental results were obtained by conducting pyrolysis experiments on PG, VG and their mixtures, in a continuous flow tube reactor at reaction temperatures ranging between 550°C and 850°C. The main gas products were predominantly CO, CH4, C2H4, in addition to C2H6, C2H2, H2, and CO2. Gas product concentrations increased with temperature except for ethane, which underwent further decomposition, as expected from the elementary reactions. Liquid mixtures proved to produce more products due to reactions taking place between the different pyrolysis products obtained from PG and VG, as shown by ReaxFF-MD simulations.

Cellulose Extraction From Green Algae, Ulva Ohnoi, and Its Application to PVA‐Based Antibacterial Composite Films Incorporated With Zinc Oxide Nanoparticles

ABSTRACTCellulose was successfully extracted from green algae (Ulva ohnoi) by chemical treatments. The contents of holocellulose and α‐cellulose significantly increased from 37.6% and 3.3% to 82.5% and 63.3%, respectively, after whole extraction treatments. The extracted cellulose (EC) was mixed to polyvinyl alcohol (PVA) to prepare EC/PVA composite films with polyethylene glycol (PEG) or glycerol (GLY) as a plasticizer. The EC/3%PVA composite film showed the highest tensile strength of 54.42 MPa because of the high PVA content. Adding GLY steeply increased the elongation of the EC/3%PVA film from 3.12% to 126.76%, but adding PEG slightly decreased to 2.63%. The EC/1%PVA/PEG composite film showed the highest visible light transmittance of 84.47%, while the addition of zinc oxide nanoparticles (ZnO‐NPs) significantly improved UV‐blocking properties. In addition, the incorporation of ZnO‐NPs on the EC/PVA‐based composite films showed excellent antibacterial activity against six Gram‐positive and Gram‐negative bacteria.

Fate of inhaled electronic nicotine delivery systems (ENDS) puff constituents in the human respiratory tract

Published research on the fate of a puff from electronic nicotine delivery systems (ENDS) in the lungs is limited; more information would better inform human exposure and potential adverse outcomes from ENDS use. An ENDS puff is a mixture of multiple constituents in droplet and vapor form, including propylene glycol, vegetable glycerin, nicotine, water, and flavor chemicals. Understanding the complexity of the puff aids in developing mechanistic models that can account for the physical, physiological, and thermodynamic processes of the puff while traveling and depositing in lung airways. Previously, we developed a mathematical model to predict deposition and uptake of ENDS constituents in the oral cavity. In this study, we formulated the model for lung airways to extend to the entire respiratory tract and made adjustments to mechanisms such as phase change and nicotine protonation to study effects on droplet pH and nicotine evaporation. We conducted model simulations for two representative inhalation profiles relevant to ENDS users: mouth-to-lung and direct-to-lung inhalation. Simulation results showed that vapor uptake during ENDS use was the primary mechanism of the overall tissue dose for higher vapor pressure constituents. Nicotine protonation was unaffected by the ratio of propylene glycol to vegetable glycerin but changes to vanillin molarity impacted droplet pH and free nicotine fraction. The largest uptake and deposition occurred in the deep lung, where constituents more efficiently reach the arterial blood. Predicted total respiratory tract retention of higher vapor pressure constituents such as nicotine, propylene glycol, and benzaldehyde were 94–95%, whereas retention of lower volatility constituents such as vegetable glycerin and vanillin was 82–83%. Results also indicated regional uptake differences for the constituents evaluated in the two inhalation scenarios. Predictions from the ENDS deposition model can be linked to physiologically based pharmacokinetic (PBPK) models to determine the fate of puff constituents such as nicotine in other tissues and organs of the body and provides further basis for evaluating flavor chemicals and puff constituents based on user-specific exposure characteristics as well as internal dose to inform risk assessment of ENDS.

Fabrication of 3D-Printed Hydrocortisone Triple Pulsatile Tablet Using Fused Deposition Modelling Technology.

Hydrocortisone (HC) is the optimal drug for adolescents diagnosed with congenital adrenal hyperplasia (CAH). Because traditional dosage regimens HC are inconvenient, our study used fused deposition modeling (FDM) three-dimensional (3D) printing technology to solve the problems caused by traditional preparations. First, we designed a core-shell structure tablet with an inner instant release component and an outer delayed release shell. The instant release component was Kollicoat IR: glycerol (GLY): HC = 76.5:13.5:10. Then, we used Affinisol® HPMC 15LV to realize delayed release. Furthermore, we investigated the relationship between the thickness of the delayed release shell and the delayed release time, and an equation was derived through binomial regression analysis. Based on that equation, a novel triple pulsatile tablet with an innovative structure was devised. The tablet was divided into three components, and the drug was released multiple times at different times. The dose and release rate of the tablets can be adjusted by modifying the infill rate of the printing model. The results indicated that the triple pulsatile tablet exhibited desirable release behavior in vitro. Moreover, the physicochemical properties of the drug, excipients, filaments, and tablets were characterized. All these results indicate that the FDM 3D printing method is a convenient technique for producing preparations with intricate structures.

Cooling dynamics of droplets exposed to solid surface freezing and vitrification

Solid surface freezing or vitrification (SSF/SSV) can be done by depositing droplets of a sample, e.g., cells in a preservation solution, onto a pre-cooled metal surface. It is used to achieve higher cooling rates and concomitant higher cryosurvival rates compared to immersion of samples into liquid nitrogen. In this study, numerical simulations of SSF/SSV were conducted by modeling the cooling dynamics of droplets of cryoprotective agent (CPA) solutions. It was assumed that deposited droplets attain a cylindrical bottom part and half-ellipsoidal shaped upper part. Material properties for heat transfer simulations including density, heat capacity and thermal conductivity were obtained from the literature and extrapolated using polynomial fitting. The impact of CPA type, i.e., glycerol (GLY) and dimethyl sulfoxide (DMSO), CPA concentration, and droplet size on the cooling dynamics was simulated at different CPA mass fractions at temperatures ranging from −196 to 25 °C. Simulations show that glycerol solutions cool faster compared to DMSO solutions, and cooling rates increase with decreasing CPA concentration. However, we note that material property data for GLY and DMSO solutions were obtained in different temperature and concentration ranges under different conditions, which complicated making an accurate comparison. Experimental studies show that samples that freeze have a delayed cooling response early on, whereas equilibration times are similar compared to samples that vitrify. Finally, as proof of concept, droplets of human red blood cells (RBCs) were cryopreserved using SSV/SSF comparing the effect of GLY and DMSO on cryopreservation outcome. At 20% (w/w), similar hemolysis rates were found for GLY and DMSO, whereas at 40%, GLY outperformed DMSO.

E-Cigarette Exposure Alters Neuroinflammation Gene and Protein Expression in a Murine Model: Insights from Perinatally Exposed Offspring and Post-Birth Mothers.

The use of E-cigarettes, often considered a safer alternative to traditional smoking, has been associated with high rates of cellular toxicity, genetic alterations, and inflammation. Neuroinflammatory impacts of cigarette smoking during pregnancy have been associated with increased risks of adverse childhood health outcomes; however, it is still relatively unknown if the same propensity is conferred on offspring by maternal vaping during gestation. Results from our previous mouse inhalation studies suggest such a connection. In this earlier study, pregnant C57BL/6 mice were exposed daily to inhaled E-cig aerosols (i.e., propylene glycol and vegetable glycerin, [PG/VG]), with or without nicotine (16 mg/mL) by whole-body inhalation throughout gestation (3 h/d; 5 d/week; total ~3-week) and continuing postnatally from post-natal day (PND) 4-21. As neuroinflammation is involved in the dysregulation of glucose homeostasis and weight gain, this study aimed to explore genes associated with these pathways in 1-mo.-old offspring (equivalent in humans to 12-18 years of age). Results in the offspring demonstrated a significant increase in glucose metabolism protein levels in both treatment groups compared to filtered air controls. Gene expression analysis in the hypothalamus of 1 mo. old offspring exposed perinatally to E-cig aerosols, with and without nicotine, revealed significantly increased gene expression changes in multiple genes associated with neuroinflammation. In a second proof-of-principal parallel study employing the same experimental design, we shifted our focus to the hippocampus of the postpartum mothers. We targeted the mRNA levels of several neurotrophic factors (NTFs) indicative of neuroinflammation. While there were suggestive changes in mRNA expression in this study, levels failed to reach statistical significance. These studies highlight the need for ongoing research on E-cig-induced alterations in neuroinflammatory pathways.

Compostable lignin grafted poly(ε-caprolactone) polyurethane biomedical materials: Shape memory, foaming capabilities, and biocompatibility

Biodegradable shape memory poly(e-caprolactone) (PCL)-based polyurethane (PU) have garnered substantial attention in biomedical applications, due to their unique properties that can recover their original shapes when exposed to temperature stimulus close to body temperature (∼35 °C). This study entails an in situ one-pot synthesis of a compostable shape memory PU system that uses PCL as soft chain segments, 1,4-butanediol (BDO) and glycerol (GLY) as chain extenders, which was then grafted with lignin hard segment and/or crosslinking nodes. The addition of renewable and sustainable lignin not only enhanced the mechanical properties of the PU, but also improved the resulting shape memory effects by increasing the shape fixing and recovery ratio. In PCL system containing BDO (PCL-BDO), 5 wt% lignin loading yields shape fixity and shape recovery ratios of 93.2 % and 81.4 %, respectively. Similarly, 5 wt% lignin in PCL systems containing GLY (PCL-GLY exhibited high shape fixity (64.4 %) and shape recovery ratio (81.4 %), respectively. Rheological characterizations showed strong evidence that the melt strength of both the PCL-BDO and PCL-GLY increased with the presence of lignin, which directly improved the physical foaming capabilities of PCL-based PU. The biocompatibility assessment also showed that the developed shape memory PCL-lignin based PU were not cytotoxic and capable of supporting cell adhesion and cell growth.

Nicotine, Humectants, and Tobacco-Specific Nitrosamines (TSNAs) in IQOS Heated Tobacco Products (HTPs): A Cross-Country Study.

Heated Tobacco Products (HTPs) purport to reduce exposure to tobacco-related toxicants compared to combustible cigarettes. This cross-sectional study examined the content of nicotine, two humectants (propylene glycol (PG) and vegetable glycerin (VG)), and four tobacco-specific nitrosamines (TSNAs: NNN, NNK, NAT, and NAB) in the tobacco filler of a popular HTP brand (IQOS). Non-menthol and menthol IQOS sticks were purchased from nine countries between 2017 and 2020 and were classified into two versions ("Bold" and "Light") using Philip Morris's flavor descriptors. The average nicotine concentration was 4.7 ± 0.5 mg/stick, and the highest nicotine concentration was found in products from Japan (5.1 ± 0.2 mg/stick). VG was the dominant humectant found in all sticks, with an average concentration of (31.5 ± 2.3 mg/stick). NNN, NNK, and NAT were substantially higher in the "Bold" sticks than the "Light" sticks. Significant differences between countries for TSNAs were also observed: the NAT and NAB contents were the highest in the "Light" products from Canada (192.5 ± 24.1 and 22.9 ± 1.0 ng/stick, respectively); the NNK concentration was the highest in the "Bold" products from Poland (64.8 ± 7.9 ng/stick); and the highest NNN concentrations were observed in the "Bold" products from South Africa (488.9 ± 26.7 ng/stick). As NNN and NNK are known human carcinogens, and as humectants like PG and VG can degrade into toxic carbonyl compounds upon heating, monitoring the concentration of these chemicals in HTPs is important for protecting users' health and ensuring compliance with regulations.

Toxicological Aspects Associated with Consumption from Electronic Nicotine Delivery System (ENDS): Focus on Heavy Metals Exposure and Cancer Risk.

Tobacco smoking remains one of the leading causes of premature death worldwide. Electronic Nicotine Delivery Systems (ENDSs) are proposed as a tool for smoking cessation. In the last few years, a growing number of different types of ENDSs were launched onto the market. Despite the manufacturing differences, ENDSs can be classified as "liquid e-cigarettes" (e-cigs) equipped with an atomizer that vaporizes a liquid composed of vegetable glycerin (VG), polypropylene glycol (PG), and nicotine, with the possible addition of flavorings; otherwise, the "heated tobacco products" (HTPs) heat tobacco sticks through contact with an electronic heating metal element. The presence of some metals in the heating systems, as well as in solder joints, involves the possibility that heavy metal ions can move from these components to the liquid, or they can be adsorbed into the tobacco stick from the heating blade in the case of HTPs. Recent evidence has indicated the presence of heavy metals in the refill liquids and in the mainstream such as arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), and lead (Pb). The present review discusses the toxicological aspects associated with the exposition of heavy metals by consumption from ENDSs, focusing on metal carcinogenesis risk.

Chemical Composition of Electronic Vaping Products From School Grounds in California.

The use of electronic vaping products (EVPs) containing nicotine, marijuana, and/or other substances remains prominent among youth; with EVPs containing nicotine being the most commonly used tobacco product among youth since 2014. However, a detailed understanding of the chemical composition of these products is limited. From February 25th to March 15th, 2019, a total of 576 EVPs, including 233 e-cigarette devices (with 43 disposable vape pens) and 343 e-liquid cartridges/pods/bottled e-liquids, were found or confiscated from a convenience sample of 16 public high schools in California. Liquids inside 251 vape pens and cartridges/pods/bottled e-liquids were analyzed using a gas chromatography/mass spectrometry (GC/MS). For comparison, new JUUL pods, the most commonly used e-cigarette among youth during 2018-2019, with different flavorings and nicotine content were purchased and analyzed. For e-cigarette cartridges/pods/bottled e-liquids, nicotine was detected in 204 of 208 (98.1%) samples. Propylene glycol and vegetable glycerin were dominant solvents in nicotine-containing EVPs. Among 43 disposable vape pen devices, cannabinoids such as tetrahydrocannabinol (THC) or cannabidiol (CBD) were identified in 39 of 43 (90.1%) samples, of which three contained both nicotine and THC. Differences in chemical compositions were observed between confiscated or collected JUULs and purchased JUULs. Measured nicotine was inconsistent with labels on some confiscated or collected bottled e-liquids. EVPs from 16 participating schools were found to widely contain substances with known adverse health effects among youth, including nicotine and cannabinoids. There was inconsistency between labeled and measured nicotine on the products from schools. This study measured the main chemical compositions of EVPs found at 16 California public high schools. Continued efforts are warranted, including at the school-level, to educate, prevent, and reduce youth use of EVPs.

Solvothermal synthesis of bismuth-based halide perovskites: Investigating the influence of alcohol solvents on photocatalytic performance

Our study explores the effect of different solvents on the synthesis of bismuth-based halide perovskite (BHP) crystals with distinct morphologies. BHP crystals were successfully synthesized using various alcohol solvents, including ethanol (EtOH), butanol (BuOH), ethylene glycol (EG), glycerol (GL), and without the use of alcohol solvents. The choice of solvent acted a crucial role in shaping the nucleation and growth of BHP crystals, as it affected key solvent characteristics, including dielectric constant, ion-coordination, and atomic chain length. The resulting BHP crystals exhibited varying geometrical and structural features, which, in turn, significantly impacted their photophysical properties and photocatalytic activity for the degradation of organic pollutants under visible light irradiation. The introduction of EtOH into the synthesis process led to larger crystallite sizes and an increased adsorption of oxygen molecules on BHP, thereby enhancing the separation of photo-excited electrons and holes. Consequently, the photodegradation efficiency of rhodamine B achieved an impressive 99.6% after 30 min of irradiation. The degradation rate of tetracycline hydrochloride over BHP photocalysts followed this order: mesoporous structure with strong agglomeration of particles (EtOH) > irregular agglomerates composed of spherical particles (BuOH) > irregular clusters of sheets (EG) > thick plates (GL) > flower-like agglomerates (without the use of an alcohol solvent). Our evaluation considered changes in morphological characteristics, surface properties, and photon absorption capacities of the BHP crystalline structures. This study provides valuable insights into the role of various alcohol solvents in tailoring the structure and improving the photocatalytic performance of BHP photocatalyst synthesized through the solvothermal route.

Development of Antioxidant and Antimicrobial Membranes Based on Functionalized and Crosslinked Chitosan for Tissue Regeneration.

Tissue engineering is an interdisciplinary field that develops new methods to enhance the regeneration of damaged tissues, including those of wounds. Polymer systems containing bioactive molecules can play an important role in accelerating tissue regeneration, mitigating inflammation process, and fighting bacterial infection. Chitosan (CS) has attracted much attention regarding its use in wound healing system fabrication thanks to its biocompatibility, biodegradability, and the presence of functional groups in its structure. In this work, bioactive chitosan-based membranes were obtained by both chemical and physical modifications of the polymer with glycidyl methacrylate and glycerol (GLY), respectively. The most suitable GLY concentration to obtain wound healing systems with good elongation at break, a good water vapor transmission rate (WVTR), and good wettability values was 20% (w/w). Afterwards, the membranes were crosslinked with different concentrations of ethylene glycol dimethacrylate (EGDMA). By using a concentration of 0.05 mM EGDMA, membranes with a contact angle and WVTR values suitable for the application were obtained. To make the system bioactive, 3,4-dihydrocinnamic acid (HCAF) was introduced into the membranes, either by imbibition or chemical reaction, using laccase as a catalyst. Thermal and mechanical analyses confirmed the formation of a cohesive network, which limited the plasticizing effect of GLY, particularly when HCAF was chemically bound. The HCAF-imbibed membrane showed a good antioxidant and antimicrobial activity, highlighting the potential of this system for the treatment of wound healing.

In vitro toxicological evaluation of aerosols generated by a 4th generation vaping device using nicotine salts in an air-liquid interface system

BackgroundElectronic cigarettes (EC) have gained popularity, especially among young people, with the introduction of fourth-generation devices based on e-liquids containing nicotine salts that promise a smoother vaping experience than freebase nicotine. However, the toxicological effects of nicotine salts are still largely unknown, and the chemical diversity of e-liquids limits the comparison between different studies to determine the contribution of each compound to the cytotoxicity of EC aerosols. Therefore, the aim of this study was to evaluate the toxicological profile of controlled composition e-liquid aerosols to accurately determine the effects of each ingredient based on exposure at the air-liquid interface.MethodsHuman lung epithelial cells (A549) were exposed to undiluted aerosols of controlled composition e-liquids containing various ratios of propylene glycol (PG)/vegetable glycerin (VG) solvents, freebase nicotine, organic acids, nicotine salts, and flavoured commercial e-liquids. Exposure of 20 puffs was performed at the air-liquid interface following a standard vaping regimen. Toxicological outcomes, including cytotoxicity, inflammation, and oxidative stress, were assessed 24 h after exposure.ResultsPG/VG aerosols elicited a strong cytotoxic response characterised by a 50% decrease in cell viability and a 200% increase in lactate dehydrogenase (LDH) production, but had no effects on inflammation and oxidative stress. These effects occurred only at a ratio of 70/30 PG/VG, suggesting that PG is the major contributor to aerosol cytotoxicity. Both freebase nicotine and organic acids had no greater effect on cell viability and LDH release than at a 70/30 PG/VG ratio, but significantly increased inflammation and oxidative stress. Interestingly, the protonated form of nicotine in salt showed a stronger proinflammatory effect than the freebase nicotine form, while benzoic acid-based nicotine salts also induced significant oxidative stress. Flavoured commercial e-liquids was found to be cytotoxic at a threshold dose of ≈ 330 µg/cm².ConclusionOur results showed that aerosols of e-liquids consisting only of PG/VG solvents can cause severe cytotoxicity depending on the concentration of PG, while nicotine salts elicit a stronger pro-inflammatory response than freebase nicotine. Overall, aerosols from fourth-generation devices can cause different toxicological effects, the nature of which depends on the chemical composition of the e-liquid.

Complete thermal characterization of liquids by front photopyroelectric configuration using the reference sample method

We explored the use of the front photopyroelectric (FPPE) configuration and the reference sample method to determine the thermal properties of liquid samples such as extra virgin olive oil and aqueous glycerol (GL), ethylene glycol (EG), and sodium chloride (NaCl) solutions. The thermal diffusivity (α) and thermal conductivity (k) were determined from photopyroelectric phase and amplitude signals, respectively, using water as a reference. The thermal effusivity (e) and volumetric heat capacity (ρc) were also determined based upon both obtained thermal properties. All thermal properties of GL and EG in aqueous solutions decrease as their volume fraction increases at an average rate of 5% for concentrations higher than 20% and between 23% and 10% for concentrations less than 20%. The Matvienko and Mandelis’ model for α and our proposed expression for ρc described this trend with a reliable approximation to the experimental data with R 2 about 0.97 and 0.99, respectively. Moreover, the frequency of a specific angle is proportional to α as established by the theory for the phase signal for thermally thick samples. In the case of aqueous NaCl solutions, the α and k values were slightly below 4.6% and 3% from water values reported at room temperature. The proposed method allows the simultaneous determination of α and k by using only the FPPE configuration with test and reference liquid samples, reducing time and uncertainties from the use of more than one experimental setup, and providing the complete thermal characterization.

Time-dependent hormesis transfer from five high-frequency personal care product components to mixtures

There is potential for personal care products (PCPs) components and mixtures to induce hormesis. How hormesis is related to time and transmitted from components to mixtures are not clear. In this paper, we conducted determination of components in 16 PCP products and then ran frequent itemset mining on the component data. Five high-frequency components (HFCs), betaine (BET), 1,3-butanediol (BUT), ethylenediaminetetraacetic acid disodium salt (EDTA), glycerol (GLO), and phenoxyethanol (POE), and 14 mixtures were identified. For each mixture system, one mixture ray with the actual mixture ratios in the products was selected. Time-dependent microplate toxicity analysis was used to test the luminescence inhibition toxicity of five HFCs and 14 mixture rays to Vibrio qinghaiensis sp.-Q67 at 12 concentration gradients and eight exposure times. It is showed that BET, EDTA, POE, and 13 mixture rays containing at least one J-type component showed time-dependent hormesis. Characteristic parameters used to describe hormesis revealed that the absolute value of the maximum stimulatory effect (|Emin|) generally increased with time. Notably, mixtures composed of POE and S-type components showed greater |Emin| than POE alone at the same time. Importantly, the maximum stimulatory effective concentration, NOEC/the zero effective concentration point, and EC50 remained relatively stable. Nine hormesis transmission phenomena were observed in different mixture rays. While all mixtures primarily exhibited additive action, varying degrees of synergism and antagonism were noted in binary mixtures, with no strong synergism or antagonism observed in ternary and quaternary mixtures. These findings offer valuable insights for the screening of HFCs and their mixtures, as well as the study of hormesis transmission in personal care products.

Strong and anti-freezing alginate-based hydrogel with humidity response and wide-temperature-range strain sensing ability

To get strong and anti-freezing hydrogel with multiple contact and non-contact sensing performance, a facial method is proposed in this work using multiple physical bonding crosslinking and glycerol (GL) immersing strategy. The obtained hydrogels show a tensile stress at break of 5.4 MPa, an elongation at break of 1420 %, and a compression strength of 12.2 MPa at 80 % strain. Additionally, benefiting from the GL immersing the hydrogel shows superior anti-freezing (no ice formation at −60 °C) and water retention ability (water loss less than 17 % after storing at 50 °C for 7 h). Furthermore, the volume resistance of hydrogels exhibits excellent responses against humidity, temperature, strain, and stress. The variation of the resistance against temperature can be well described by the Arrhenius equation with an activation energy of 501.3 meV, verifying a band-gap dominated diffusion hopping conductive mechanism of the hydrogel. The sufficient humidity and temperature responses make the hydrogel applicable as a non-contact sensor, and the wide temperature strain sensing (−40 to 50 °C) and stress sensing capability ensures that the hydrogel can be used as a contact sensor, ensuring that the hydrogel can be used as perfect flexible sensor for monitoring human motion and physiological signals.

Tobacco-derived and tobacco-free nicotine cause differential inflammatory cell influx and MMP-9 in mouse lung

BackgroundElectronic nicotine delivery systems (ENDS) or electronic cigarettes (e-cigarettes) aerosolize an e-liquid composed of propylene glycol (PG) and vegetable glycerin (VG) as humectants, flavoring chemicals, and nicotine. Nicotine naturally occurs in two isomers R- and S-nicotine, with tobacco-derived nicotine (TDN) composed of S-nicotine, and tobacco-free/synthetic nicotine (TFN) composed of a racemic mixture of R- and S-nicotine. Currently, there is limited knowledge of the potential differences in the toxicity of TFN versus TDN. We hypothesized that exposure of TFN and TDN salts to C57BL/6J mice would result in a differential response in lung inflammation and protease/ antiprotease imbalance.MethodsFive-week-old male and female C57BL/6J mice were exposed to air, PG/VG, PG/VG with TFN salts (TFN), or PG/VG with TDN salts (TDN) by nose-only exposure. Lung inflammatory cell counts, cytokine/chemokine levels, and matrix metalloproteinase (MMP) protein abundance and activity levels were determined by flow cytometry, ELISA, immunoblotting, and gel zymography, respectively.ResultsExposure to the humectants (PG/VG) alone increased cytokine levels- IL-6, KC, and MCP-1 in the BALF and KC levels in lung homogenate of exposed mice. While no change was observed in the cytokine levels in lung homogenate of TDN aerosol exposed mice, exposure to TFN aerosols resulted in an increase in KC levels in the lungs of these mice compared to air controls. Interestingly, exposure to TDN aerosols increased MMP-9 protein abundance in the lungs of female mice, while exposure to TFN aerosol showed no change. The metabolism of nicotine or the clearance of cotinine for TFN exposure may differ from that for TDN.ConclusionExposure to humectants, PG/VG alone, induces an inflammatory response in C57BL/6J mice. TFN and TDN salts show distinct changes in inflammatory responses and lung proteases on acute exposures. These data suggest variable toxicological profiles of the two forms of nicotine in vivo. Future work is thus warranted to delineate the harmful effects of synthetic/natural nicotine with humectants to determine the potential toxicological risks for users.

The combination of propylene glycol and vegetable glycerin e-cigarette aerosols induces airway inflammation and mucus hyperconcentration

Despite concerns over their safety, e-cigarettes (e-cigs) remain a popular tobacco product. Although nicotine and flavors found in e-cig liquids (e-liquids) can cause harm in the airways, whether the delivery vehicles propylene glycol (PG) and vegetable glycerin (VG) are innocuous when inhaled remains unclear. Here, we investigated the effects of e-cig aerosols generated from e-liquid containing only PG/VG on airway inflammation and mucociliary function in primary human bronchial epithelial cells (HBEC) and sheep. Primary HBEC were cultured at the air–liquid interface (ALI) and exposed to e-cig aerosols of 50%/50% v/v PG/VG. Ion channel conductance, ciliary beat frequency, and the expression of inflammatory markers, cell type-specific markers, and the major mucins MUC5AC and MUC5B were evaluated after seven days of exposure. Sheep were exposed to e-cig aerosols of PG/VG for five days and mucus concentration and matrix metalloproteinase-9 (MMP-9) activity were measured from airway secretions. Seven-day exposure of HBEC to e-cig aerosols of PG/VG caused a significant reduction in the activities of apical ion channels important for mucus hydration, including the cystic fibrosis transmembrane conductance regulator (CFTR) and large conductance, Ca2+-activated, and voltage-dependent K+ (BK) channels. PG/VG aerosols significantly increased the mRNA expression of the inflammatory markers interleukin-6 (IL6), IL8, and MMP9, as well as MUC5AC. The increase in MUC5AC mRNA expression correlated with increased immunostaining of MUC5AC protein in PG/VG-exposed HBEC. On the other hand, PG/VG aerosols reduced MUC5B expression leading overall to higher MUC5AC/MUC5B ratios in exposed HBEC. Other cell type-specific markers, including forkhead box protein J1 (FOXJ1), keratin 5 (KRT5), and secretoglobin family 1A member 1 (SCGB1A1) mRNAs, as well as overall ciliation, were significantly reduced by PG/VG exposure. Finally, PG/VG aerosols increased MMP-9 activity and caused mucus hyperconcentration in sheep in vivo. E-cig aerosols of PG/VG induce airway inflammation, increase MUC5AC expression, and cause dysfunction of ion channels important for mucus hydration in HBEC in vitro. Furthermore, PG/VG aerosols increase MMP-9 activity and mucus concentration in sheep in vivo. Collectively, these data show that e-cig aerosols containing PG/VG are likely to be harmful in the airways.