Range Of Ethanol Concentrations Research Articles

Wide-range ethanol sensor based on a spray-deposited nanostructured ZnO and Sn–doped ZnO films

This study compares the performance of a highly sensitive ethanol sensor incorporating a zinc oxide (ZnO) nanostructured film with that of (1–3) % tin-doped zinc oxide (Sn–ZnO) nanostructured films across a wide range of ethanol concentrations from 0.5 to 400 ppm. X-ray diffraction analysis confirms the polycrystalline structure of Sn–ZnO films, with a significant (002) plane orientation. Notably, Sn doping reduces the optical bandgap from 3.28 eV (ZnO) to 2.41 eV (3% Sn–ZnO). Ethanol vapor sensing experiments reveal that the 2% Sn–ZnO film operates at a lower temperature of 220 °C compared to the ZnO film (290 °C). Particularly, the 2% Sn–ZnO film exhibits rapid and strong responses to low ethanol concentrations (0.5–100 ppm) at this temperature. Response values of 2.22 ± 0.01 and 17.66 ± 0.08 with response times of 11 ± 1 and 15 ± 1 s are achieved at ethanol concentrations of 0.5 and 400 ppm, respectively. Conversely, the ZnO film performs better at higher ethanol concentrations (150–400 ppm). These findings advance gas sensing mechanisms in ZnO and Sn–ZnO films, with implications for future advancements in gas sensor technology.

The analytical performance of Saccharomyces cerevisiae and Bacillus megaterium microbial consortium as recognition element in ethanol biosensor

Abstract. Nurdiani, Iswantini D, Nurhidayat N, Wahyuni WT, Kartono A. 2023. The analytical performance of Saccharomyces cerevisiae and Bacillus megaterium microbial consortium as recognition element in ethanol biosensor. Biodiversitas 24: 5928-5936. Alcohol, particularly ethanol, is commonly found in human food and plays a significant role in degenerative diseases and disability. Accurate measurement of alcohol in food products is essential to ensure adherence to the Muslim halal rule. However, existing alcohol biosensor that relies on a single microbe has limitations in measuring a wide range of ethanol concentrations. To address this issue, a microbial consortium is needed to expand the measurable range. Therefore, this study aimed to develop an innovative biosensor to widen the range of measured ethanol concentrations based on the microbial consortium of Saccharomyces cerevisiae YSAPMI.2 and Bacillus megaterium BSAPMI.1. The performance of the biosensor was evaluated using the cyclic voltammetry method. The results showed that the linear range, linearity, coefficient of determination, sensitivity, and response time, were 0.02-6.0%, 0.9968, 0.9936, 83.157 µA (%)-1, and 11 seconds. The LoD ??and LoQ theoretical values ??of the method obtained in the ethanol oxidation reaction were 0.060% and 0.182%, respectively. The confirmatory test for the LoD value of 0.01% yielded a positive response, while the confirmed LoQ value of 0.02% showed good precision and accuracy. The biosensor had precise %RSD values of 0.568, 1.338, and 4.632% for the high, medium, and low ethanol concentrations, respectively. The accuracy reflected as the recovery percentage was in the range of 90.27-111.07%. The biosensor was relatively specific and had no interferences with common ethanol compounds including methanol, sodium chloride, formic acid, and glucose. The stability obtained with biofilm showed a better result reaching 88% in 70 days. Based on the result, this microbial consortium biosensor could widen the range of measured ethanol concentrations and should be further developed to create a prototype for an accurate and practical analysis.

Marangoni effect on hydrodynamics and mass transfer behavior in an internal loop airlift reactor under elevated pressure

AbstractThe Marangoni effect on the hydrodynamics and mass transfer was studied in an internal loop airlift reactor with the addition of ethanol under elevated pressure. The overall gas holdup αg increased by ~10% and the gas–liquid volumetric mass‐transfer coefficient kla increased by ~20% on average for each one bar increase in pressure. When the mole fraction of ethanol xE increased from 0 to 0.012, αg increased by ~110% and kla increased by ~50%. However, when xE increased from 0.012 to 0.11, αg decreased by ~40% and kla decreased by ~25%. This volcano‐shaped relationship between both hydrodynamics and mass transfer behavior and ethanol concentration was determined by the Marangoni effect. Semi‐empirical correlations of αg and kla were proposed by including the Marangoni effect in a wide range of ethanol concentration and operating conditions. These correlations gave good predictions of αg and kla compared with extensive experimental data in the literature.

Butanol as a major product during ethanol and acetate chain elongation.

Chain elongation is a relevant bioprocess in support of a circular economy as it can use a variety of organic feedstocks for production of valuable short and medium chain carboxylates, such as butyrate (C4), caproate (C6), and caprylate (C8). Alcohols, including the biofuel, butanol (C4), can also be generated in chain elongation but the bioreactor conditions that favor butanol production are mainly unknown. In this study we investigated production of butanol (and its precursor butyrate) during ethanol and acetate chain elongation. We used semi-batch bioreactors (0.16L serum bottles) fed with a range of ethanol concentrations (100-800mM C), a constant concentration of acetate (50mM C), and an initial total gas pressure of ∼112kPa. We showed that the butanol concentration was positively correlated with the ethanol concentration provided (up to 400mM C ethanol) and to chain elongation activity, which produced H2 and further increased the total gas pressure. In bioreactors fed with 400mM C ethanol and 50mM C acetate, a concentration of 114.96 ± 9.26mM C butanol (∼2.13gL-1) was achieved after five semi-batch cycles at a total pressure of ∼170kPa and H2 partial pressure of ∼67kPa. Bioreactors with 400mM C ethanol and 50mM C acetate also yielded a butanol to butyrate molar ratio of 1:1. At the beginning of cycle 8, the total gas pressure was intentionally decreased to ∼112kPa to test the dependency of butanol production on total pressure and H2 partial pressure. The reduction in total pressure decreased the molar ratio of butanol to butyrate to 1:2 and jolted H2 production out of an apparent stall. Clostridium kluyveri (previously shown to produce butyrate and butanol) and Alistipes (previously linked with butyrate production) were abundant amplicon sequence variants in the bioreactors during the experimental phases, suggesting the microbiome was resilient against changes in bioreactor conditions. The results from this study clearly demonstrate the potential of ethanol and acetate-based chain elongation to yield butanol as a major product. This study also supports the dependency of butanol production on limiting acetate and on high total gas and H2 partial pressures.

Room temperature ethanol sensor based on ZnO nanoparticles modified by WSe2 nanosheets

Ethanol gas sensors have been widely applied in food safety, biomedicine, and fuel processing. However, most ethanol sensors need to be operated at high temperature. The development of room temperature ethanol sensors with low cost and high sensitivity is still a challenge. Here, a low-cost room temperature ethanol gas sensor is realized by connecting interdigital electrodes (IDEs) coated with ZnO/WSe2 nanocomposite film in series with a quartz crystal resonator (QCR). The change in ethanol gas concentration can be converted into a frequency shift of the quartz resonator to generate a quasi-digital signal through the sensor. Compared with pure ZnO IDEs-SQCR sensor, the sensitivity of ZnO/WSe2 IDEs-SQCR sensor (4.87 Hz/ppm) has been significantly improved in ethanol concentration range of 0–400 ppm. This is mainly attributed to the introduction of WSe2 with good conductivity, which not only enables the composite to have a special layered three-dimensional structure conducive to the adsorption and diffusion of gas molecules, but also puts the resistance of the composite in a more sensitive tuning range. The proposed sensor can be fabricated on a printed circuit board (PCB) so as to reduce the cost of mass production.

Novel Corrugated Long Period Grating Surface Balloon-Shaped Heterocore-Structured Plastic Optical Fibre Sensor for Microalgal Bioethanol Production.

A novel long period grating (LPG) inscribed balloon-shaped heterocore-structured plastic optical fibre (POF) sensor is described and experimentally demonstrated for real-time measurement of the ultra-low concentrations of ethanol in microalgal bioethanol production applications. The heterocore structure is established by coupling a 250 μm core diameter POF between two 1000 μm diameter POFs, thus representing a large core-small core-large core configuration. Before coupling as a heterocore structure, the sensing region or small core fibre (SCF; i.e., 250 μm POF) is modified by polishing, LPG inscription, and macro bending into a balloon shape to enhance the sensitivity of the sensor. The sensor was characterized for ethanol-water solutions in the ethanol concentration ranges of 20 to 80 %v/v, 1 to 10 %v/v, 0.1 to 1 %v/v, and 0.00633 to 0.0633 %v/v demonstrating a maximum sensitivity of 3 × 106 %/RIU, a resolution of 7.9 × 10-6 RIU, and a limit of detection (LOD) of 9.7 × 10-6 RIU. The experimental results are included for the intended application of bioethanol production using microalgae. The characterization was performed in the ultra-low-level ethanol concentration range, i.e., 0.00633 to 0.03165 %v/v, that is present in real culturing and production conditions, e.g., ethanol-producing blue-green microalgae mixtures. The sensor demonstrated a maximum sensitivity of 210,632.8 %T/%v/v (or 5 × 106 %/RIU as referenced from the RI values of ethanol-water solutions), resolution of 2 × 10-4%v/v (or 9.4 × 10-6 RIU), and LOD of 4.9 × 10-4%v/v (or 2.3 × 10-5 RIU). Additionally, the response and recovery times of the sensor were investigated in the case of measurement in the air and the ethanol-microalgae mixtures. The experimentally verified, extremely high sensitivity and resolution and very low LOD corresponding to the initial rate of bioethanol production using microalgae of this sensor design, combined with ease of fabrication, low cost, and wide measurement range, makes it a promising candidate to be incorporated into the bioethanol production industry as a real-time sensing solution as well as in other ethanol sensing and/or RI sensing applications.

In-situ oriented Sc-Co3O4 nanowire arrays for highly efficient ethanol detection

Improving the response of gas sensors has always been a hot research topic. Due to their unique electronic energy level structure, the compositing rare-earth (RE) element materials display unique properties in many fields such as catalysis, luminescence, and energy conversion. Along these lines, combining materials with the RE element of scandium (Sc) is considered a new method to optimize the performance of sensors based on the employment of ZIF-67 derived Co3O4 nanowire arrays. In this work, the Sc element was uniformly distributed on the surface of the Co3O4 nanowires, which were grown by enforcing hydrothermal and chemical bath-based methods. Based on the 30 % Sc composite Co3O4 nanowire array, the sensors show a maximum response of 32–100 ppm ethanol at a lower operating temperature (110 °C). The variation of the response was small range even after 35 days. Interestingly, the extracted response has increased more than three times that of the pure Co3O4 nanowire array devices. In addition, we tested the ethanol concentration range of 10–500 ppm and showed good performance. The gas-sensing properties of the sensors were systematically tested towards volatile organic compounds, including ethanol, acetone, methanol, etc. Based on the 30 % Sc composite Co3O4 nanowire array, the sensors still exhibit excellent selectivity to ethanol. The enhanced sensing performance is attributed to the strong catalytic effect of Sc and the modification of the surface morphology of Co3O4 by Sc. Our work provides an effective and promising method for improving the ethanol sensing performance of the ZIF-67 derived Co3O4 nanowires at low-temperature values.

Coarse-Grained Molecular Dynamics Simulations of Paclitaxel-Loaded Polymeric Micelles.

A continuous manufacturing technology based on coaxial turbulent jet in coflow was previously developed to produce paclitaxel-loaded polymeric micelles. Herein, coarse-grained molecular dynamics (CG-MD) simulations were implemented to better understand the effect of the material attributes (i.e., the drug-polymer ratio and the ethanol concentration) and process parameters (i.e., temperature) on the self-assembly process of polymeric micelles as well as to provide molecular details on micelle instability. An all-atom (AA) poly (ethylene glycol)-poly (lactic acid) (PEG-PLA) polymer model was developed as the reference for parameterizing a coarse-grained (CG) model, and the AA polymer model was further validated with experimental glass transition temperature (Tg). The model transferability was verified by comparing structural properties between the AA and CG models. The CG model was further validated with experimental data, including micelle particle size measurements and drug encapsulation efficiency. Furthermore, the encapsulation of paclitaxel into the polymeric micelles was included in the simulations, taking into consideration the interactions between the paclitaxel and the polymers. The results from various points of view demonstrated a strong dependence of the shape of the micelles on the drug encapsulation, with micelles transitioning from spherical to ellipsoidal structures with an increasing paclitaxel amount. Simulation data were also used to identify the critical aggregation number (i.e., the number of polymer and drug molecules required for transition from one shape to another). Improved micellar structural stability was found with a larger micellar size and less solvent accessibility. Lastly, an evaluation was performed on the micellar dissociation free energy using a steered molecular dynamics simulation over a range of temperatures and ethanol concentrations. These simulations revealed that at higher ethanol and temperature conditions, micelles become destabilized, resulting in greater paclitaxel release. The increased drug release was determined to originate from the solvation of the hydrophobic core, which promoted micellar swelling and an associated reduction in hydrophobic interactions, leading to a loosely packed micellar structure.

Embedded Transdermal Alcohol Detection via a Finger Using SnO2 Gas Sensors.

In this paper, we report the fabrication and characterization of a portable transdermal alcohol sensing device via a human finger, using tin dioxide (SnO2) chemoresistive gas sensors. Compared to conventional detectors, this non-invasive technique allowed us the continuous monitoring of alcohol with low cost and simple fabrication process. The sensing layers used in this work were fabricated by using the reactive radio frequency (RF) magnetron sputtering technique. Their structure and morphology were investigated by means of X-ray spectroscopy (XRD) and scanning electron microscopy (SEM), respectively. The results indicated that the annealing time has an important impact on the sensor sensitivity. Before performing the transdermal measurements, the sensors were exposed to a wide range of ethanol concentrations and the results displayed good responses with high sensitivity, stability, and a rapid detection time. Moreover, against high relative humidity (50% and 70%), the sensors remained resistant by showing a slight change in their gas sensing performances. A volunteer (an adult researcher from our volunteer group) drank 50 mL of tequila in order to realize the transdermal alcohol monitoring. Fifteen minutes later, the volunteer’s skin started to evacuate alcohol and the sensor resistance began to decline. Simultaneously, breath alcohol measurements were attained using a DRAGER 6820 certified breathalyzer. The results demonstrated a clear correlation between the alcohol concentration in the blood, breath, and via perspiration, which validated the embedded transdermal alcohol device reported in this work.

Mutual influence of ethanol and surfactin on their wetting and adhesion properties

The measurements of the contact angle of aqueous solution of ethanol and surfactin mixture in the whole range of ethanol concentration on PTFE, PMMA and quartz were made at changing ethanol concentration and constant of surfactin and vice versa. Based on the obtained results, the Young-Dupre and van Oss et al. equations, the intermolecular interactions parameter between the solution and solid phases was determined and used to explain the possibility to form the ethanol and surfactin mixed layer beyond the solution drop settled on the PMMA and/or quartz surface. This layer pressure and that at the PMMA-solution, the quartz-solution interface was determined using the Young-Dupre and van Oss et al. equations and applied for the ethanol and surfactin Frumkin isotherm adsorption determination. The Gibbs adsorption isotherm was also determined. The ethanol and surfactin Gibbs and Frumkin isotherms at the solid-solution, solid-air interfaces were compared to those at the solution-air one. From these isotherms of surfactin and ethanol adsorption at three interfaces, the slope of the linear dependence between the adhesion and surface tension was explained. The Gibbs isotherm was applied for determination of the Gibbs standard free energy of ethanol and surfactin adsorption at the solid-air and solid-water interfaces.

Development of a laminar burning velocity empirical correlation for combustion of iso-octane/ethanol blends in air

This study presents the first demonstration of Marshall and Hinton’s empirical correlation for laminar burning velocity (LBV) applied to iso-octane/ethanol blends. The “Oxford” correlation is first validated for neat iso-octane and ethanol combustion against the outputs of three different chemical kinetics mechanisms and experimental data from the literature. The effects of three different mixing rules, simple energy fraction, modified Le Châtelier, and modified version of the more complex mixing law of Hirasawa, on the predicted LBVs of iso-octane/ethanol blends are evaluated. The modified Le Châtelier mixing law is used with the Oxford correlation to predict blend LBVs at various temperature and pressure conditions. The results are validated against previously unpublished data for iso-octane/ethanol binary fuels at elevated temperature and pressure (up to 10 bar) both from this group, and from the earlier experimental studies of Varea et al. (CORIA) and Broustail et al. (PRISME). The Oxford correlation is shown to perform well across a wide range of temperature and pressure conditions (respectively 298–640 K and 1–10 bar) for the single component fuels. Used in conjunction with a modified Le Châtelier mixing law, the LBVs predicted by the correlation provide an excellent match to the available experimental data across the full range of ethanol concentrations examined (25, 50, and 75% v/v).

Колебательная спектроскопия тонких пленок конденсатов смеси этанола с инертным газом

It is known that by changing the concentration in an inert medium, it is possible to form clusters of various sizes of any substance by condensing them on a cold substrate from the gas phase. Traditionally, such systems are presented by molecular cryocrystals. This paper demonstrates the results of IR spectro­metric studies of cryovacuum condensates of ethanol mixture with nitrogen. The main task of this study is to explain the complex, most often, ambiguous behavior of thin films of ethanol cryovacuum conden­sates in the process of its co­condensation with nitrogen. For this purpose, vibrational spectroscopy of cryodeposited thin films of “ethanol in nitrogen” mixtures in various concentration ratios was performed. The objects of research are thin films of cryocondensates of ethanol mixture with inert gas (N2). The sam­ples were condensed at the temperature T = 16 K. The pressure of the gas phase of the mixture during cryocondensation was kept at P = 10­5 Torr. The range of ethanol concentrations in the mixtures varied from 3% to 90%. The spectral range of measurements was considered in 400­-4200 1/cm. It is assumed that the change in the concentration of ethanol in the mixture leads to the formation of various cluster compositions of ethanol molecules dissolved in an inert medium.

A novel colorimetric indicator for ethanol detection in preserved baby mangoes

A colorimetric indicator cube for use in smart packaging was designed and fabricated to detect ethanol produced by microbial fermentation in preserved baby mangoes. The presence and level of ethanol was indicated by color variations of the indicator cube, which consists of porous melamine foam (MF) that entraps an indicator solution of potassium dichromate and sulfuric acid. Within the packaging, the cube sits behind a gas-permeable membrane. The morphological structure of MF was studied by digital microscope and X-ray fluorescence analysis. In the optimal condition, the indicator cube exhibited distinct color changes from yellow to brown, green and blue over an ethanol concentration range from 0.25% to 5.0%. Color changes were clearly visible to the naked eye. The repeatability of the ethanol indicator cube was good and storage stability was maintained for up to 19 and 74 days at room and refrigeration temperatures, respectively. The smart packaging was applied to detect ethanol in preserved baby mangoes at different storage times.

Rheological properties of cellulosic thickeners in hydro-alcoholic media: The science behind the formulation of hand sanitizer gels

Cellulosic-based thickeners are commonly used in the preparation of hydro-alcoholic hand sanitisers. Yet, little is known about the behaviour of these polymeric dispersions in hydro-alcoholic mixtures. Here, we studied the dispersion ability and rheology of hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose and sodium carboxymethyl cellulose in water–ethanol mixtures. Hydroxypropyl cellulose formed transparent dispersions across the entire range of ethanol concentrations, while a critical ethanol concentration (CEC), above which dispersions became turbid, was found for all the other polymers. At and below the CEC, all the rheological parameters followed a bell-like shape profile as a function of ethanol concentration. Moreover, the molecular weight and degree of substitution of the polymers influenced the rheological properties. The CEC and rheological behaviour of the dispersions were both dependent on the ethanol/polymer and water/polymer interactions. As hand disinfectants should contain 60–95% ethanol, polymers of higher CEC, such as hydroxypropyl cellulose and hydroxypropyl methylcellulose, are recommended.

“Sniffing” Toxic Methanol in Laced Beverages By a Fully-Integrated and Portable Analyzer

Introduction In July 2019, more than 20 people died in Costa Rica due to methanol-tainted alcohol of registered and unregistered brands [1]. Similar outbreaks have been reported in India [2] (95 deaths, February 2019), Iran [3] (768 cases, 2018) or Cambodia [4] (237 cases, 2018). In fact, 5400 intoxications and 1500 deaths were reported due to methanol-tainted alcohol within the last two years [5]. Apparently, cheap methanol is intentionally added to alcoholic beverages to increase their potency and profit. In the human body, methanol is converted to formaldehyde and formic acid, which can interfere with the human metabolism leading to blindness or even death [6]. Therefore, handheld analyzers or sensors to screen beverages are urgently needed to prevent such intoxication. These could be applied by tourist or even first responders.However, compact gas sensors either suffer from insufficient detection limit (legal limit of 0.09 vol% in fruit distilled spirits [7]), cannot distinguish methanol from the chemically similar ethanol present at much higher concentration or have not been validated with real beverages. Here, we present a stand-alone, inexpensive and miniaturized analyzer for screening of potential safety hazards in beverages [8] that can be applied even for hand sanitizers. Method The handheld device consists of a printed circuit board with integrated microcontroller and circuitry to operate metal-oxide gas sensors (Figure 1a). A miniaturized pump (12 g) is used to guide the sample through a sorption filter for analyte pre-separation to a highly sensitive and flame-made Pd-doped SnO2 sensor [9]. The sample was obtained from the headspace above liquors. The device was calibrated with laboratory mixtures containing methanol and ethanol in ultra-pure water at concentrations ranging from 0.01 – 10 vol% and 5 – 80 vol%, respectively. Subsequently, the device was tested with real beverages including beer, sake, Baileys, Arrack, pear spirit and Stroh rum. The drinks were chosen to cover a wide range of ethanol concentrations (5 – 80 vol%) and flavors that might interfere with the detector. The methanol concentration of the pure drinks was determined by liquid chromatography. To generate higher methanol concentrations, the pure beverages were spiked with methanol up to 10 vol%. Results and Conclusions In laboratory mixtures, methanol (1 vol%) and ethanol (5 vol%) passed through the separation column with retention times of 1.6 and 5.3 min, respectively, that can be detected subsequently (thus selectively) by the Pd-doped SnO2 sensor. Thereby, the effective separation of methanol and ethanol is crucial. This was evaluated by comparing the retention time of methanol to the breakthrough time of ethanol. For methanol, the retention time ranged from 1.25 – 1.5 min depending on concentration, from 0.01 to 10 vol%. Importantly, the breakthrough time of ethanol was always larger than 2.2 min. This enabled reliable and simultaneous detection of methanol and ethanol, even at their lowest and highest concentrations, respectively.For all alcoholic beverages, no interference originating from the different flavors was observed on the methanol and ethanol quantification. Most importantly, the device predicted methanol and ethanol with average error of 21.9 and 13.4% (with respect to the actual concentration), when tested in 43 pure and methanol spiked beverages (Figure 1b). Also, the performance was reproducible and stable for at least 107 days. As a result, the validated device could readily be applied by laymen (e.g. tourists) or first responders to screen beverages for toxic methanol and prevent severe health damage.

Perception of Aqueous Ethanol Binary Mixtures Containing Alcohol-Relevant Taste and Chemesthetic Stimuli

Ethanol is a complex stimulus that elicits multiple gustatory and chemesthetic sensations. Alcoholic beverages also contain other tastants that impact flavour. Here, we sought to characterize the binary interactions between ethanol and four stimuli representing the dominant orosensations elicited in alcoholic beverages: fructose (sweet), quinine (bitter), tartaric acid (sour) and aluminium sulphate (astringent). Female participants were screened for thermal taste status to determine whether the heightened orosensory responsiveness of thermal tasters (n = 21–22) compared to thermal non-tasters (n = 13–15) extends to these binary mixtures. Participants rated the intensity of five orosensations in binary solutions of ethanol (5%, 13%, 23%) and a tastant (low, medium, high). For each tastant, 3-way ANOVAs determined which factors impacted orosensory ratings. Burning/tingling increased as ethanol concentration increased in all four binary mixture types and was not impacted by the concentration of other stimuli. In contrast, bitterness increased with ethanol concentration, and decreased with increasing fructose concentration. Sourness tended to be reduced as ethanol concentration increased, although astringency intensity decreased with increasing concentration of fructose. Overall, thermal tasters tended to be more responsive than thermal non-tasters. These results provide insights into how the taste and chemesthetic profiles of alcoholic beverages across a wide range of ethanol concentrations can be manipulated by changing their composition.

Vapor-phase modulated sphere-like In2O3@N-C complexes for improving gas sensitivity

Sensitivity is a challenging issue for most gas sensors in detecting volatile organic compounds (VOCs). In this study, an alternative ethanol chemosensor based on In2O3@N-C nanospheres (NSs) was synthesized successfully through a simple vapor-phase method. The In2O3@N-C NSs structure, morphology and chemical states were characterized by XRD, SEM, TEM (HRTEM), XPS, and PL measurements. The gas sensor based on In2O3@N-C NSs showed high sensitivity for a wide range of ethanol concentrations (0.5–200 ppm). The N-C shell increased the concentration of oxygen vacancies, thereby increasing the number of active sites as verified by XPS and PL. We investigated the effect of the N–C shell on gas sensitivity. Compared with the pure In2O3 sensor, the In2O3@N-C NS sensor exhibited significantly enhanced sensing performance toward ethanol with a response to 100 ppm ethanol was approximately 145, at least seven times higher than the other gases and two times higher than the pure In2O3 NS sensor (83). As the relative humidity increased, the sensor sensitivity decreased. However, even under a high humidity environment of 70%, the response of the In2O3@N-C NS sensor was still above 20. Our results indicated that In2O3@N-C NSs are prospective candidates for ethanol gas sensor fabrication.

Bifacial biological effects of ethanol: acetaldehyde production by oral Streptococcus species and the antibacterial effects of ethanol against these bacteria

ABSTRACT Background:Many previous studies have focused on the acetaldehyde produced from ethanol by oral bacteria as a risk factor for oral cancer. Most of these studies involved low ethanol concentrations (ca. 10 mM), but oral bacteria are exposed to a wide range of ethanol concentrations (100–10,000 mM) when alcoholic beverages are consumed. In contrast, ethanol is widely used at high concentrations (> 5,000 mM) as an antiseptic/disinfectant, suggesting that ethanol has bifacial biological effects; i.e. it acts as both a metabolic substrate for bacterial acetaldehyde production and an antimicrobial agent. Materials and methods:We examined the acetaldehyde production from ethanol by oral streptococci and the effects of ethanol exposure on the growth and viability of these bacteria at a wide range of ethanol concentrations (10–10,000 mM). Results:Acetaldehyde production was the highest at an ethanol concentration of 2,000 mM (2.1–48-fold higher than that seen at an ethanol concentration of 10 mM). Bacterial growth was inhibited by > 1,000 mM of ethanol, and the bacteria did not seem viable in the presence of > 5,000 mM of ethanol, although they still produced acetaldehyde. Conclusion:Ethanol has bifacial biological effects, and the concentration ranges of these effects overlap.

Hormetic effects of alcohol in an astroglial cellular model and its proteomics signature

AbstractBackgroundHormesis or the adaptive stress response is a biphasic dose response to a factor which has a beneficial effect on cells or an organism at low doses while having a toxic effect at higher doses (1). Alcohol has been considered both a cause and protective factor for dementia (2) and arguably has a biphasic effect on brain cells. This study evaluated the dose‐ response relationship of ethanol on astrocytes in vitro, considering the importance of astrocytes in the support, maintenance and repair of neurons and the blood brain barrier (3). Cellular proteomics was performed to examine likely mechanisms underlying the effect.MethodsAn astrocyte cell line (U‐251) was used, incubating cells with increasing concentrations of ethanol. Cell viability and toxicity were evaluated by MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) and LDH (Lactate Dehydrogenase) Assay assays respectively. Proteomic profiling was performed (LC‐MS/MS) to assess differential protein expression in response to ethanol in the hormetic range, and at different timepoints after exposure (12 and 24hrs).ResultsAt low concentrations (0.1% to 1%) ethanol was stimulatory to U‐251 cell growth, and at high doses (5% to 20%) toxic effects were observed, demonstrating a biphasic curve in response to ethanol (Figure 1 & 2). Proteomic evaluation using cells exposed to hormetic doses of ethanol showed significant upregulation of proteins involved in DNA repair and cellular response to stress and DNA damage functions at 12 hours (Figure 3), while at 24 hours protein expression changes mostly related to apoptosis and regulation of reactive oxygen species (Figure 4).ConclusionThese results show that at low doses ethanol has a hormetic effect on the U‐251 astrocyte cell line, and a biphasic dose response curve is observed across the full ethanol concentration range. Proteomics profiling suggests that mechanisms of cellular protection within the hormetic range include upregulation of stress response proteins, DNA protection and factors which promote cell growth.

Ethanol in Combination with Oxidative Stress Significantly Impacts Mycobacterial Physiology.

Here, we investigate the mycobacterial response to the combined stress of an organic oxidant (cumene hydroperoxide [CHP]) and a solvent (ethanol). To understand the interaction between the two stressors, we treated Mycobacterium smegmatis cells to a range of ethanol concentrations (2.5% to 10% [vol/vol]) in combination with a subinhibitory concentration of 1 mM CHP. It was observed that the presence of CHP increases the efficacy of ethanol in inducing rapid cell death. The data further suggest that ethanol reacts with the alkoxy radicals to produce ethanol-derived peroxides. These radicals induce significant membrane damage and lead to cell lysis. The ethanol-derived radicals were primarily recognized by the cells as organic radicals, as was evident by the differential upregulation of the ohr-ohrR genes that function in cells treated with the combination of ethanol and CHP. The role of organic peroxide reductase, Ohr, was further confirmed by the significantly higher sensitivity of the deletion mutant to CHP and the combined stress treatment of CHP and ethanol. Moreover, we also observed the sigma factor σB to be important for the cells treated with ethanol alone as well as the aforementioned combination. A ΔsigB mutant strain had significantly higher susceptibility to the stress conditions. This finding was correlated with the σB-dependent transcriptional regulation of ohr and ohrR In summary, our data indicate that the combination of low levels of ethanol and organic peroxides induce ethanol-derived organic radicals that lead to significant oxidative stress on the cells in a concentration-dependent manner.IMPORTANCE Bacterial response to a combination of stresses can be unexpected and very different compared with that of an individual stress treatment. This study explores the physiological and transcriptional response of mycobacteria in response to the combinatorial treatment of an oxidant with the commonly used solvent ethanol. The presence of a subinhibitory concentration of organic peroxide increases the effectiveness of ethanol by inducing reactive peroxides that destroy the membrane integrity of cells in a significantly short time span. Our work elucidates a mechanism of targeting the complex mycobacterial membrane, which is its primary source of intrinsic resistance. Furthermore, it also demonstrates the importance of exploring the effect of various stress conditions on inducing bacterial clearance.